Title of Invention

RECORDING INK, INK MEDIA SET, AND INK CARTRIDGE

Abstract A recording ink containing: a solid component containing a colorant, and a resin, and being solid in ink at 25 C, a liquid component having a boiling point higher than that of water and being liquid in ink at 25 C, and water, wherein the total amount of the solid component contained in the recording ink is equal to 8.5% by mass or higher and less than 15% by mass, a ratio (A/B) of the total amount of a water-soluble organic solvent (A), which is contained in the liquid component and has a high-boiling point of 280 C or higher (A), to the total amount of the solid component (B) contained in the recording ink is 1.1 to 2.5, and a ratio (C/B) of the total amount of the liquid component (C) in the recording ink to the total amount of the solid component (B) in the recording ink is 1.85 to 3.10.
Full Text DESCRIPTION
RECORDING INK. INK MEDIA SET. INK CARTRIDGE. INK RECORDED
MATTER. INKJET RECORDING APPARATUS. AND INKJET RECORDING
METHOD
Technical Field
The present invention relates to a recording ink suitably used for inkjet
recording, an ink media set using the recording ink, an ink cartridge, an ink recorded
matter, an inkjet recording apparatus, and an inkjet recording method.
Background Art
Inkjet recording methods are methods of printing by jetting ink droplets to
make them adhere on a recording medium such as paper. As inks used in the inkjet
recording methods, generally, a solution or dispersion liquid is used in which various
colorants such as dyes and pigments are dissolved or dispersed in water or a mixture
of water and a high-boiling point organic solvent, and to maintain moisture retention,
a large amount of a wetting agent composed of a high-boiling point organic solvent
is further contained therein. Such a wetting agent composed of a high-boiling point
organic solvent contributes to prevention of drying of nozzle ports because of its
low-volatility (evaporativity) and water-retention ability. When such an ink is used
for recording on paper having high-ink permeation, for example, with regular paper,
however, the wetting agent contained in the ink is hardly volatile, resulting in
frequent ink strike through.
Meanwhile, when a conventional ink containing a large amount of wetting
agent is used for recording on paper which has low liquid absorbability such as offset
printing coated paper (hereinafter, may be referred to as "coated paper"), ink beading
and ink bleeding are liable to occur in portions with a large amount of the ink, such
as solid parts, due to its low-permeation rate of the ink provided on a surface of the
coated paper thereinto, it takes some time to dry a recorded image because the
wetting agent is hardly likely to evaporate, causing offset smear due to spurs, smear
during conveyance, and paper stain and/or paper-sticking at paper stacked section in
a paper-feed unit, etc. Thus, such a conventional ink is inappropriate in practical
use.
In order to solve the problems, it has been desired to provide an inkjet
recording method that allows ink bleeding to hardly occur even with the use of
printing coated paper, allows ink to dry quickly, allows for high-image density and
high-image quality even when an ink is printed on regular paper, and allows nozzle
clogging to hardly occur even during long-time stoppage of printing operation.
For example, Patent Literature 1 proposes an inkjet ink containing an
extremely small amount of a wetting agent. According to the proposal, it is possible
to obtain high-quality image with high-image density without substantially causing
ink strike through even when regular paper is used. However, in this proposal, no
resin is contained in the ink, and particularly when a pigment ink is used, the fixing
ability of image is poor. Further, improvements in drying rate of ink when the ink is
printed on offset coated paper are not disclosed nor suggested in the proposal.
Patent Literature 2 proposes a quick-drying dye ink. In Examples of this
proposal, however, the amount of a wetting agent is contained 6 times the amount of
a colorant used with no addition of resin; high-quality paper is used, and printing

coated paper, which extremely hardly absorbs liquid, is not intended for use.
Patent Literature 3 proposes a quick-drying ink relating to inkjet recording
based on energization heat generation. However, the ink provided in this proposal
contains a large amount of electrolyte with no addition of resin, the fixing ability of
image is poor, and an ink-flying method is employed which is essentially different
from piezo-type inkjet method.
Further, each of Patent Literature 4 and Patent Literature 5 proposes a
combination of a micro-capsulated pigment and printing paper. However, in these
proposals, the inks have generally used ink compositions. Thus, in order to improve
the drying properties thereof, heating by microwave energy is required.
Patent Literature 6 proposes an ink containing wax fine particles and resin
fine particles. In this proposal, the wax fine particles are used in place of a wetting
agent, in terms of capability of imparting moisture retention. However, the wax fine
particles having moisture retention tend to be poor in fixing property and dryness.
Patent Literature 7 proposes an ink containing a resin emulsion, a polymer
dispersant and a pigment. The ink provided in this proposal contains a small amount
of a wetting agent, but the total dissolved solid content is low. Therefore, sufficient
image density and sufficient color-development may not be obtained.
Patent Literature 8 proposes as an ink suitable for non-porous recording
media, such as film, an ink resin emulsion which contains an aqueous liquid vehicle
with an acid function polymer colloid particle dispersed therein, and a pigment
colorant in which polymer molecules are bonded to each other, and proposes an ink
containing a polymer dispersant and a pigment. In the Examples of this proposal, a
high-boiling point wetting agent (water-soluble organic solvent) is contained about
3.5 times the solid component, and in drying process of image recorded with the ink
by leaving it under normal environments, it becomes necessary to heat and dry the
ink by means of a heat gun due to its slow drying.
Further, Patent Literature 9 describes a pigment ink in order to
simultaneously achieve two opposed objects of an object of preventing nozzle
clogging and another object of quick drying of ink on a recording medium after
recorded. In the pigment ink, the amount of glycerine contained (X), which is
effective in preventing nozzle clogging, and the amount of isopropanol contained
(Y), used as a high-volatile solvent, which is effective in drying a recoded image, are
specified within the ranges, 1 This technique does not disclose a recording ink allowing for obtaining highly sharp
images that are close in quality to recorded matters produced by commercial printing
or printed matters for publication without substantially causing ink beading and
without any problems with the drying rate of ink even when the ink is printed on
printing coated paper which has low liquid absorbability, in view of adjustments of
the ratio of three components of the colorant amount, the amount of solid contents
and the amount of the water-soluble organic solvent having a high-boiling point of
280°C or higher, besides additive amounts, and the contents. Patent Literature 10
discloses an inkjet ink in which a difference in weight ratio between nonvolatile
components contained in a recording liquid (including resin and wax) and coloring
material components falls in the range of from 0.1 to 10 at 25°C for the purpose of
improving the image density when printed on non-coated paper and improving
abrasion resistance of printed matters. Patent Literature 11 discloses an ink
containing as essential components a dye and a solvent for dissolving the dye and
further containing a fluorochemical surfactant for exhibiting quick-drying properties
by decreasing the surface tension of the ink so as to improve the wettability of the
ink to a target recording medium and a large amount of an organic solvent for
improving solubility of the fluorochemical surfactant in the ink, and described that
the surface tension of the ink at 25°C and the ink viscosity thereof at 20°C are
reduced to improve the frequency responsiveness of discharge ink by making
uniform dispersibility of the components in the ink responsive to high-speed
printing, thereby ejecting small droplets of ink. Patent Literature 12 describes an ink
in which a pigment and a micro emulsion are contained in an aqueous medium, the
micro emulsion has an average particle diameter of 50 nm or less, the amount of the
micro emulsion contained is 0.5% by mass to 10% by mass based on the total mass
of the ink, and with the use of the ink, the density of printed matters, when printed
on non-coated paper, is increased, thereby improving abrasion resistance of the
printed matters. However, these proposals do not disclose a technique allowing for
obtaining highly sharp images that are close in quality to recorded matters produced
by commercial printing or printed matters for publication without substantially
causing ink beading and without any problems with the drying rate of ink even when
printed on printing coated paper which has low liquid absorbability, in view of
adjustments of the ratio of three components of the colorant amount, the amount of
solid contents and the amount of the water-soluble organic solvent having a high-
boiling point of 280°C or higher, besides additive amounts, and the contents.
Thus, it has not been intended to apply such conventional inkjet recording
inks to recording media which have low-liquid absorbability, like printing coated
paper such as offset printing coated paper, and in the conventional inkjet recording

media, such a technique has not yet been developed that reduces the amount of a
liquid component(s) (primarily, wetting agent) which has a boiling point higher than
that of water and is liquid in ink, with focusing on the ratio with the amount of solid
components in the ink to thereby improve the permeation property of the ink, and
determines the amount of the liquid component(s) so as to fall in the range where
troubles such as a change in the orbit of the ejected ink (ejection curve) and non-
ejection of ink during printing or during short-time stoppage of printing operation,
and nozzle clogging during long-time stoppage of printing operation can be avoided.
D D Patent Literature 1 Japanese Patent Application Laid-Open (JP-A) No.
2004-115551
Patent Literature 2 Japanese Patent Appliczation Publication (JP-B) No.
60-34992
Patent Literature 3 Japanese Patent Application Laid-Open (JP-A) No. 8-
109343
Patent Literature 4 Japanese Patent Application Laid-Open (JP-A) No.
20O2-67473
Patent Literture 5 Japanese Patent Application Laid-Open (JP-A) No.
20O2-69346
Patent Literature 6 Japanese Patent Application Laid-Open (JP-A) No.
20O2-301857
Patent Literature 7 Japanese Patent Application Laid-Open (JP-A) No. 6-
171072
Patent Literature 8 Japanese Patent Application Laid-Open (JP-A) No.
2005-220352

Patent Literature 9 Japanese Patent Application Laid-Open (JP-A) No.
2003-201427
Patent Literature 10 Japanese Patent Application Laid-Open (JP-A) No. 07-
2923O2
Patent Literture 11 Japanese Patent Application Laid-Open (JP-A) No. 05-
230409
Patent Literature 12 Japanese Patent Application Laid-Open (JP-A) No. 04-
018462
Disclosure of Invention
The present invention is provided in view of the present situation in the art
and aims to solve the aforementioned various problems in the prior art and to
achieve the following objects. Specifically, the present invention aims to provide a
recording ink allowing for obtaining highly sharp images that are close in quality to
recorded matters produced by commercial printing or printed matters for publication
without substantially causing ink beading and without any problems with ink drying
rate of ink even when printed on printing coated paper which has low liquid
absorbability; an ink media set using the recording ink; an ink cartridge, ink
recording matters; an inkjet recording apparatus that allows for preventing a change
in the orbit of the ejected ink (otherwise referred to as "ejection curve") and non-
ejection of ink during printing or during short-time stoppage of printing operation,
and also allows nozzle clogging to hardly occur even during long-time stoppage of
printing operation; and an inkjet recording method.
The present invention is basd on the findings made by the present inventors,
and means for solving the above-mentioned problems are as follows:
A recording ink containing:
a solid component containing a colorant and a resin, and being solid in ink
at 25°C,
a liquid component having a boiling point higher than that of water and
being liquid in ink at 25°C, and
water,
wherein the total amount of the solid component contained in the
recording ink is equal to 8.5% by mass or higher and less than 15% by mass, a ratio
(A/B) of the total amount of a water-soluble organic solvent (A), which is contained
in the liquid component and has a high-boiling point of 280°C or higher (A), to the
total amount of the solid component (B) contained in the recording ink is 1.1 to 2.5,
and a ratio (C/B) of the total amount of the liquid component (C) in the recording ink
to the total amount of the solid component (B) in the recording ink is 1.85 to 3.10.
The recording ink according to the item , wherein the liquid
component contains a wetting agent, and the wetting agent is at least one selected
from glycerine, 1,3-butanediol, 3-methyl-l,3-butanediol, 2-pyrrolidone, and N-
methyl-2-pyrrolidone.
The recording ink according to any one of the items and ,
wherein the liquid component contains a penetrant, and the penetrant is a polyol
compound having 8 to 11 carbon atoms.
The recording ink according to any one of the items to >, wherein the liquid component contains a surfactant, and the surfactant contains a

fluorochemical surfactant.
The recording ink according to any one of the items to >, wherein the resin contains resin fine particles.
The recording ink according to the item , wherein the resin
fine particles contain an acrylic silicone resin, and the acrylic silicone resin has a
glass transition temperature of 25°C or lower.
The recording ink according to any one of the items to >, wherein the resin fine particles have a volume average particle diameter of 10 nm
to 1,000 nm in a resin emulsion.
The recording ink according to any one of the items to >, wherein the colorant is a polymer emulsion pigment in which a water-insoluble or
substantially water-insoluble coloring material is contained in polymer fine particles.
The recording ink according to any one of the items to ,
wherein the colorant is a pigment which has an anionic hydrophilic group on its
surface.
The recording ink according to any one of the items to >, having a surface tension of 35mN/m or lower at 25°C.
An ink media set containing:
the recording ink according to any one of the items to , and
a recording medium having a support and a coating layer applied onto at
least one surface of the support,
wherein the amount of pure water transferred to the recording medium for
a contact period of 100 ms measured by a dynamic scanning absorptometer is 2 mL/
m2 to 35 raL/m2, and the amount of pure water transferred to the recording medium

for a contact period of 400 ms is 3 mL/m2 to 40 mL/m2.
An ink cartridge including:
a container to accommodate the recording ink according to any one of the
items to.
An inkjet recording method containing:
jetting the recording ink according to any one of the items to
onto a recording medium so as to record an image on the recording medium, by
applying a stimulus to the recording ink.
The inkjet recording method according to the item ,
wherein the recording medium has a support and a coating layer applied onto at least
one surface of the support,
wherein the amount of pure water transferred to the recording medium for
a contact period of 100 ms measured by a dynamic scanning absorptometer is 2 mL/
m2 to 35 mL/m2, and the amount of pure water transferred to the recording medium
for a contact period of 400 ms is 3 mL/m2 to 40 mL/m2.
The inkjet recording method according to any one of the items 13 > and , wherein the stimulus is at lest one selected from heat, pressure,
vibration and light.
The inkjet recording method according to any one of the items 13 > to , wherein an inkjet head for jetting the ink has an ink repellent layer on
its plate surface where ink ejection ports are formed.
The inkjet recording method according to the item ,
wherein the ink repellent layer contains any one of a fluorine-based material and a
silicone-based material.

The inkjet recording method according to any one of the items 16 > and , wherein the ink repellent layer has a surface roughness (Ra) of 0.2
µm or less.
The inkjet recording method according to any one of the items 16 > to , wherein near ink ejection ports of the inkjet head, the cross-section
area of each of the ink ejection ports measured at a plane, which is perpendicular to a
center line of each of the ink ejection ports, gradually becomes larger with distance
from the surface of a plate base.
The inkjet recording method according to any one of the items 16 > to , wherein the ink repellent layer has a thickness of 0.1 nm or more.
The inkjet recording method according to any one of the items 16 > to , wherein the ink repellent layer has a critical surface tension of 5 mN/
m to 40 mN/m.
An inkjet recording apparatus including:
an ink jetting unit configured to jet a recording ink onto a recording
medium so as to record an image on the recording medium, by applying a stimulus
to the recording ink.
The inkjet recording apparatus according to the item ,
wherein the stimulus is at least one selected from heat, pressure, vibration and light.
An ink recorded matter including:
an image formed on a recording medium, with the use of the recording ink
according to any one of the items to .
The ink recorded matter according to the item , wherein
the recording medium has a support and a coating layer applied onto at least one

surface of the support, the amount of pure water transferred to the recording medium
for a contact period of 100 ms measured by a dynamic scanning absorptometer is 2
mL/ra2 to 35 mL/m2, and the amount of pure water transferred to the recording
medium for a contact period of 400 ms is 3 mL/m2 to 40 mL/m2.
A recording ink of the present invention contains a solid component
containing a colorant and a resin and being solid in ink at 25°C, a liquid component
having a boiling point higher than that of water and being liquid in ink at 25°C, and
water. By setting a ratio (A/B) of the total amount of a water-soluble organic solvent
having a high-boiling point of 280°C or higher (A) contained in the liquid
component to the total amount of the solid component (B) contained in the recording
ink to a value within the range of from 1.1 to 2.5, it is possible to provide an inkjet
recording apparatus that allows nozzle clogging to hardly occur even during long-
time stroppage of printing operation, and an inkjet recording method. By setting a
ratio (C/B) of the total amount of the liquid component (C) in the recording ink to
the total amount of the solid component (B) in the recording ink to a value within the
range of from 1.85 to 3.10, it is possible to provide an inkjet recording apparatus that
allows ink bleeding to hardly occur even with the use of printing coated paper which
has low-liquid absorbability, allows for obtaining highly sharp images that are close
in quality to recorded matters produced by commercial printing or printed matters
for publication without substantially causing any problems with the drying rate and
without substantially causing a change in the orbit of the ejected ink (otherwise
referred to as "ejection curve") and non-ejection of ink during printing or during
short-time stoppage of printing operation.
Further, by setting the total amount of the solid component in the recording
ink to a value within the range of from 8.5% by mass to less than 15% by mass, it is
possible to reduce the additive amount of the liquid component necessary for
preventing nozzle clogging, making it possible for ink bleeding to hardly occur as
well as to possible to further increase the drying rate.
The main constituent of the liquid component having a boiling point
higher than that of water and being liquid in ink at 25°C is a so-called wetting agent,
however, when a conventional ink containing a large amount of wetting agent is used
on printing coated paper such as offset printing coated paper, it results in occurrence
of ink bleeding caused by insufficient ink absorbability and slow drying. According
to the following Lucas-Washburn's equation, which is a basic equation for
calculating the permeation constant of liquid into a porous material, it is known that
a permeation distance "h" is proportional to one-half root of a time length "t" and
minus one-half root of a viscosity tj.
H = (R-ytcose/2Ti)1/2
However, in the equation, "h" represents a permeation distance, "t"
represents a time length required for permeation, "R" represents a thin hole diameter,
"0" represents a contact angle, and "tj" represents a dynamic viscosity.
This equation shows that when a recording medium is set, a time length
required for absorption of a same quantity of liquid is proportional to the viscosity of
the liquid and is inversely proportional to the surface tension of the liquid and cos0.
When the surface tension of an ink is not changed, there is a means of reducing the
ink viscosity (to be exact, the viscosity of the liquid component in the ink).
In this case, the ink viscosity varies depending on the amount of a wetting
agent used, and thus it is considered that the amount of the wetting agent is reduced
within a reasonable range where the ink viscosity can be lowered. However, when
the amount of the wetting agent is excessively reduced to the level where the
function of the wetting agent cannot be sufficiently exhibited, the following troubles
are liable to occur. The direction of ink ejection shifts (ejection curve or
displacement of dropping position of ink droplets), non-ejectoin of ink occurs due to
nozzle clogging during long-time stoppage of printing operation, and so on.
Meanwhile, the main constituent of the solid component in the ink is a
colorant and a resin to be contained in the ink for improving the fixing ability. The
main roll of the wetting agent in the ink is to prevent aggregation of the solid
component and adhesion thereof onto a nozzle plate.
In an ink which adheres on a nozzle plate, the moisture content is reduced
primarily due to evaporation of water with a lapse of time, however, a wetting agent
having a high-boiling point and a small amount of water remain, and this makes it
possible to prevent aggregation and contact of a particulate solid component in the
ink, and thus the binding of the solid component can be prevented.
In an ink dropped on a recording medium, a liquid component is removed
from the vicinity of the surface of the recording medium because of permeation of
the liquid component into the medium. The main constituents of the liquid
component of the ink are water and a wetting agent. Even when a wetting agent
having high-viscosity is used as the wetting agent, and the amount of the wetting
agent used is small, the viscosity of the liquid component (containing water) is low.
Therefore, water and the wetting agent are removed from the vicinity of the surface

of the recording medium without separating each other, the solid content (a pigment
and a resin as a fixing agent) of the ink remains in image area on the surface of the
recording medium, a slight amount of the wetting agent remains, and thus sufficient
fixing property can be exhibited.
Similarly to the required amount of a binder resin to the solid component
in the ink, it is considered that the required amount of the liquid component
(primarily, a wetting agent) having a boiling point higher than that of water, in the
ink and being liquid in ink at 25°C and used for preventing the binding of the solid
component is substantially proportional to the additive amount of the solid
component in the ink. In this way, when the amount of the solid component is small,
the required amount of the liquid component becomes small, and when the amount
of the solid component is large, the required amount of the liquid component
becomes large.
Therefore, the recording ink of the present invention contains a solid
component containing a colorant and a resin and being solid in ink at 25°C, a liquid
component having a boiling point higher than that of water and being liquid in ink at
25°C and water, wherein the total amount of the solid component contained in the
recording ink is within the range of from 8.5% by mass to less than 15% by mass; a
ratio (A/B) of the total amount of a water-soluble organic solvent having a high-
boiling point of 280°C or higher (A) contained in the liquid component to the total
amount of the solid component (B) contained in the recording ink is set to a value
within the range of from 1.1 to 2.5; and a ratio (C/B) of the total amount of the liquid
component (C) in the recording ink to the total amount of the solid component (B) in
the recording ink to a value within the range of from 1.85 to 3.10. By setting the

value of the ratio (C/B) within the range, it is possible to obtain highly sharp images
that are close in quality to recorded matters produced by commercial printing or
printed matters for publication without substantially causing beading and without
any problems with the drying rate of ink even when printed on printing coated paper
which has low liquid absorbability.
An ink cartridge of the present invention includes a container to
accommodate the recording ink of the present invention. The ink cartridge is
suitably used in printers and the like base on inkjet recording system. When the ink
accommodated in the ink cartridge is used and an image etc. is printed on printing
coated paper having low liquid absorbability, it is possible to increase the drying rate
of the ink and to record highly sharp images that are close in quality to recorded
matters produced by commercial printing or printed matters for publication.
An inkjet recording apparatus of the present invention includes at least an
ink jetting unit configured to jet the recording ink of the present invention so as to
record an image, by applying energy to the ink. In the inkjet recording apparatus, the
ink jetting unit applies energy to the recording ink of the present invention and jets
the recording ink so as to record an image. As a result, when the recording ink is
printed on printing coated paper which has low liquid absorbability, it is possible to
increase the drying rate of the ink and to obtain highly sharp images that are close in
quality to recorded matters produced by commercial printing or printed matters for
publication.
An inkjet recording method of the present invention includes at least
jetting the recording ink of the present invention so as to record an image by
applying energy to the ink. In the ink jetting step of the inkjet recording method, the

recording ink of the present invention is jetted by applying energy to the recording
ink so as to record an image. As a result, when the recording ink is printed on
printing coated paper which has low liquid absorbability, it is possible to increase the
drying rate of recorded image and to obtain highly sharp images that are close in
.quality to recorded matters produced by commercial printing or printed matters for
publication.
When the inkjet recording method of the present invention is employed,
nozzle clogging is least likely to occur even during long-time stoppage of printing
operation.
The phrase "long-time stoppage" means that a nozzle is left intact in a state
where its nozzle section is capped with a capping unit and stopped for a day or
longer time.
An ink media set of the present invention includes the recording ink of the
present invention, and a recording medium which has a support and a coating layer
i on at least one surface of the support, wherein the amount of pure water transferred
to the recording medium for a contact time of 100 ms measured by a dynamic
scanning liquid absorptometer is 2 mL/m2 to 35 mL/m2, and the amount of pure
water transferred to the recording medium for a contact time of 400 ms is 3 mL/m2 to
40 mL/m2.
In the ink media set of the present invention, the recording ink of the
present invention is combined with a recording medium in which the transfer amount
of pure water is within the predetermined range, whereby an image having glossiness
and high-uniformity of density can be recorded without causing beading in solid
portions.

An ink recorded matter of the present invention has an image that is
formed on a recording medium by the use of the recording ink of the present
invention. When the recording ink is printed on a substantially smooth printing
paper having low liquid absorbability, the drying rate is increased, and a highly sharp
image that is close in quality to recorded matters produced by commercial printing or
printed matters for publication can be held on the recording medium as the ink
recorded matter of the present invention.
In the present invention, "beading" means a phenomenon where in inkjet
recording, during a time span from the time when a first ink droplet is dropped on a
surface of a recording medium until the next ink droplet is dropped on the surface,
the first droplet cannot be sufficiently absorbed into the recording medium and
remains in a liquid state on the surface of the recording medium, part of the droplet
remained is then mixed with droplets dropped thereafter, and a colorant in the ink
(organic pigment, etc.) partially becomes a mass, resulting in nonuniform density. In
recently generally used printers, this phenomenon has relationship to the amount of
ink absorbed to a recording medium for a relatively short period of contact time up
to 100 ms at the latest. For instance, in a green image portion, the beading level
varies depending upon the amount of a yellow (Y) ink (or a cyan (C) ink) absorbed
into a recording medium (transfer amount) during the time span from the time when
the yellow (Y) ink (or the cyan (C) ink) is dropped on a surface of the recording
medium until the C ink (or the Y ink) is dropped on the surface of the recording
medium. Beading is likely to occur in secondary colors of green, red, and blue,
however, when the amount of the ink absorbed into a recording medium is small, ink
beading may occur in primary colors of cyan, magenta, yellow, and black.

The present invention can solve various conventional problems and
provide a recording ink allowing for obtaining recorded matters produced by
commercial printing or printed matters for publication without substantially causing
ink beading and without any problems with the ink drying rate of image recorded
> with ink even when printed on printing coated paper which has low liquid
absorbability; an ink media set using the recording ink, an ink cartridge, ink recorded
matters, an inkjet recording apparatus that allows nozzle clogging to hardly occur
even during long-time stoppage of printing operation, and an inkjet recording
method.
Brief Description of Drawing
FIG. 1 is a schematic diagram showing one example of an ink cartridge of
the present invention.
FIG. 2 is a schematic diagram exemplarily showing the ink cartridge
shown in FIG. 1 with the inclusion of a case.
FIG. 3 is a schematic explanatory view showing one example of an inkjet
recording apparatus of the present invention.
FIG. 4 is a schematic explanatory view exemplarily showing the internal
f
structure of the inkjet recording apparatus shown in FIG. 3.
FIG. 5 is a schematic enlarged view exemplarily showing an inkjet head of
the present invention.
FIG. 6 is a schematic view showing rows of nozzles on an inkjet head of
the present invention.
FIG. 7 is an exploded perspective view showing a liquid supply device in
an inkjet recording apparatus of the present invention.
FIG. 8 is an enlarged exploded perspective view of the liquid supply
device shown in FIG. 7.
FIG. 9 is an explanatory side view showing a sub tank.
FIG. 10A is a schematic cross-sectional view separated at an A-A line
shown in FIG. 9.
FIG. 10B is another schematic cross-sectional view separated at an A-A
line shown in FIG. 9.
FIG. 11 is a top view of units for maintaining an inkjet printer of the
present invention.
FIG. 12 is a schematic explanatory view showing one example of units for
maintaining an inkjet printer of the present invention.
FIG. 13 is a schematic cross-sectional view showing one example of a
nozzle plate for an inkjet head of the present invention.
FIG. 14A is a schematic explanatory view showing another example of a
nozzle plate for an inkjet head of the present invention.
FIG. 14B is a schematic explanatory view showing still another example
of a nozzle plate for an inkjet head of the present invention.
FIG. 14C is a schematic explanatory view showing still yet another
example of a nozzle plate for an inkjet head of the present invention.
FIG. 15A is a schematic explanatory view showing nozzle plates for inkjet
heads, for comparison.
FIG. 15B is a schematic explanatory view showing nozzle plates for inkjet
heads, for comparison.
FIG. 15C is a schematic explanatory view showing nozzle plates for inkjet
heads, for comparison.
FIG. 16 is a view showing a state where a silicone resin is applied to a
nozzle plate surface using a dispenser to form an ink-repellency layer.
FIG. 17A is a view showing a relation between a coating port at the tip of a
needle of the present invention and the coating width of a nozzle plate to be coated.
FIG. 17B is a view showing a relation between a coating port at the tip of a
commonly used needle and the coating width of a nozzle plate to be coated.
FIG. 18 is a diagram showing coating operation using a dispenser.
FIG. 19 is a diagram showing a state where an ink repellency layer
composed of silicone resin is formed up to a desired depth of an inner wall of a
nozzle.
FIG. 20 is a view showing one example of an inkjet head of the present
invention, and showing a state where a nozzle hole is formed by excimer laser
processing.
FIG. 21 is a view showing a structure of an excimer laser processor used
for processing nozzle holes.
FIG. 22 A is a view showing a base of a nozzle-forming component in a
nozzle plate preparing step in a method of producing an inkjet head.
FIG. 22B is a view showing a step of forming an SiO2 thin layer on a
surface of a resin film.
FIG. 22C is a view showing a step of applying a fluorine-based water
repellant onto the SiO2 thin film.
FIG. 22D is a view showing a step of leaving the water repellency layer in
the air after evaporation thereof.
FIG. 22E is a view showing a step of affixing an adhesive tape to the water
repellency layer.
FIG. 22F is a view showing a step of processing a nozzle hole.
FIG. 23 is a view showing the outline of an apparatus used when an inkjet
head is manufactured by a method for producing an inkjet head of the present
invention.
Best Mode for Carrying Out the Invnetion
(Recording Ink)
A recording ink of the present invention contains at least a solid
component containing a colorant and a resin and being solid in ink at 25°C and a
liquid component having a boiling point higher than that of water and being liquid in
ink at 25°C, and water and further contains other components in accordance with the
necessity.
9
In the recording ink of the present invention, the total amount of the solid
component contained in the recording ink is within the range of from 8.5% by mass
to less than 15% by mass, more preferably within the range of 9% by mass to 14%
by mass, and particularly preferably within the range of 10% by mass to 12% by
mass.
By setting the total amount of the solid component contained in the
recording ink to less than 15% by mass, it is possible to reduce the additive amount
of the liquid component required for preventing nozzle clogging, and thus it allows
ink beading to hardly occur and the drying rate of recorded image can be further
improved.
When the total amount of the solid component contained in the recording
ink is more than 15% by mass, the amount of the liquid component (primarily,
wetting agent) having a boiling point higher than that of water and being liquid in
ink at 25°C and required for preventing nozzle clogging becomes large, and thus the
amount of the wetting agent remained in recorded image areas in the vicinity of the
surface of the recording medium becomes large, and the drying rate becomes slow.
This prevents binding of the solid component itself (a pigment and a resin as a fixing
agent per se) and binding between the solid component and the recording medium,
resulting in a degradation in fixing ability. In the meanwhile, when the total amount
of the solid component contained in the recording ink is less than 8.5% by mass, the
amount of the liquid component including water contained in the ink is large, and
therefore, unfavorably, the drying rate becomes slow, and cockling and curling are
liable to occur on the recording medium.
The ratio (A/B) of the total amount of a water-soluble organic solvent
having a high-boiling point of 280°C or higher (A) contained in the liquid
component to the total amount of the solid component (B) contained in the recording
ink is set to a value within the range of 1.1 to 2.5, preferably within the range of 1.2
to 2.0, and more preferably within the range of 1.4 to 1.8. By setting the value of the
ratio (A/B) to 1.1 to 2.5, it is possible to provide an inkjet recording apparatus and an

inkjet recording method each of which allows nozzle clogging to hardly occur even
during long-time stoppage of printing operation (the long-time reliability is
improved). When the ratio (A/B) is less than 1.1, nozzle clogging is likely to occur
during long-time stoppage of printing operation, and even when actions for
maintenance and recovery are carried out, the problem with nozzle clogging may not
be sometimes resolved.
When the ratio (A/B) is more than 2.5, the ink absorbability (permeability)
and the drying property of image degrade, and the fixing ability (abrasion resistance)
degrades.
The ratio (C/B) of the total amount of the liquid component (C) in the
recording ink to the total amount of the solid component (B) in the recording ink is
set to a value within the range of from 1.85 to 3.10, and more preferably within the
range of from 1.90 to 2.60. By setting the value of the ratio (C/B) to 1.85 to 3.10, it
is possible to provide an inkjet recording apparatus and an inkjet recording method
that allow for obtaining highly sharp images that are close in quality to recorded
matters produced by commercial printing or printed matters for publication without
substantially causing ink beading and without any problems with ink drying rate
even when printed on printing coated paper which has low liquid absorbability, and
without causing a change in the orbit of the ejected ink (otherwise, referred to as
"ejection curve") and non-ejection of ink during printing or during short-time
stoppage of printing operation (the short-term reliability is improved). When the
ratio (C/B) is less than 1.85, a change in the orbit of ejected ink (otherwise, referred
to as "ejection curve") is likely to occur during printing or during short-time
stoppage of printing operation, although the drying rate of the ink is increased.

When the ratio (C/B) is more than 3.10, ink beading is likely to occur due to a
degradation in permeability of the ink, and the drying rate of recorded image
becomes slow, resulting in a degradation in fixing ability (abrasion resistance).
in ink at 25°C >
As the liquid component having a boiling point higher than that of water
and being liquid in ink at 25°C, the most part of the liquid component is a wetting
agent having a high boiling point, and further, ink property controlling agents, such
as penetrant and surfactant, also belong to the liquid component.
The ratio of the total amount of the liquid component having a boiling
point higher than that of water and being liquid in ink at 25°C to the total amount of
the solid component in the recording ink is 1.85 to 3.10. The smaller the amount of
the liquid component having a boiling point higher than that of water and being
liquid in ink at 25°C, the shorter the drying rate of the ink becomes, however, to
prevent a change in the orbit of ejected ink (also referred to as "ejection curve") and
non-ejection of ink during printing or during short-time stoppage of printing
operation, attributable to an increase in the ink viscosity caused by drying of ink in
the vicinity of a nozzle, more strict control will be required.
Further, with the use of an ink less containing the total amount of the
liquid component having a boiling point higher than that of water and being liquid in
ink at 25°C in the recording ink, the drying of recorded images quickly proceeds
even when recorded on paper that hardly absorbs liquid, such as coated paper for
offset printing, and it is possible to obtain images with high-glossiness and less
conspicuity of beading.

When the total amount of the liquid component having a boiling point
higher than that of water and being liquid in ink at 25°C contained in the recording
ink is more than 33% by mass, the drying rate of recorded image on printing coated
paper such as offset printing coated paper lowers, and ink strike-through may
frequently occur when printed on regular paper. However, the smaller the amount of
the liquid component having a boiling point higher than that of water and being
liquid in ink at 25°C contained in the liquid component, the more the drying rate is
increased.
Note that in the liquid component having a boiling point higher than that
of water and being liquid in ink at 25°C, a wetting agent having a boiling point
higher than that of water is contained, and a penetrant and a surfactant, if they have a
boiling point higher than that of water and are liquid in ink at 25°C, are contained.
In short, it aims to improve the permeability (absorbability) and the drying property
of the ink so as to prevent the occurrence of beading and to shorten the drying rate
even when printed on paper having low liquid absorbability like printing coated
paper by reducing the amount of liquid which is more hardly dry than water as much
as possible.
- Wetting agent (water-soluble organic solvent and solid wetting agent) -
A wetting agent typified by the liquid component having a boiling point
higher than that of water and being liquid in ink at 25°C is not particularly limited
and may be suitably selected in accordance with the intended use, as long as it is
liquid in ink at 25°C. Examples thereof include polyhydric alcohols, polyhydric
alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic
compounds, amides, amines, sulfur-containing compounds, propylene carbonates,
and ethylene carbonates. These may be used alone or in combination.
Examples of the polyhydric alcohols include ethylene glycol, diethylene
glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 2,3-
butanediol, 1,4-butanediol, 3-methyl- 1,3-butanediol, 1,5-pentanediol, 1,6-
hexanediol, 2-methyl-2,4-pentanediol, tetraethylene glycol, polyethylene glycol,
glycerine, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, andpetriol.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol
monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl
ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether,
triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol
monobutyl ether, triethylene glycol isobutyl ether, tetraethylene glycol monomethyl
ether, propylene glycol monoethyle ether, dipropylene glycol monobutyl ether,
tripropylene glycol monomethyl ether, and tripropylene glycol monobutyl ether.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol
monophenyl ether, and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compounds include N-
methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-
dimethylimidazolidinone, and e-caprolactam.
Examples of the amides include formamide, N-methylformamide, and
N,N-dimethylformamide.
Examples of the amines include monoethanol amine, diethanolamine,
triethanolamine, monoethylamine, diethylamine, and triethylamine.

Examples of the sulfur-containing compounds include dimethylsulfoxide,
sulforan, thiodiethanol, and thiodiglycol.
Among these, from the perspective of the jetting stability of ink, glycerine,
2-pyrrolidone, diethylene glycol, thiodiethanol, polyethylene glycol, triethylene
glycol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentanediol, N-methyl-2-
pyrrolidone, 1,3-butanediol, 3-methyl-l,3-butanediol are preferable. Of these,
glycerine, 1,3-butanediol, 3-methyl- 1,3-butanediol, 2-pyrrolidone, and N-methyl-2-
pyrrolidone are particularly preferable.
In order to prevent such troubles with a change in the direction of ink
ejected during printing (ejection curve or displacement of dropping position of ink
droplets), non-ejection of ink due to nozzle clogging during long-time stoppage and
the like, it is preferable that the liquid component having a boiling point higher than
that of water and being liquid in ink at 25°C be contained in a large amount in the
ink, however, in particular, to prevent the occurrence of non-ejection due to nozzle
clogging during long-time stoppage, it is preferable that the rate (A/B) of the total
amount of the water-soluble organic solvent having a high-boiling point of 280°C or
higher (A) to the total amount of the solid component (B) in the recording ink be 1.1
to 2.5. As the water-soluble organic solvent having a high-boiling point, glycerin is
particularly preferable because it has a high-boiling point (290°C), hardly evaporates
and has a high equilibrium moisture regain in low-humidity environment.
Note that in the present invention, the boiling point is a boiling point
measured under a normal atmospheric pressure of 760 mmHg (1,013.3 hPa).
Examples of the solid wetting agent include sugars, sugar alcohols,
hyaluronic acid salts, trimethylolpropane, and 1,2,6-hexanetriol.

By setting the ratio of the total amount of the liquid component having a
higher boiling point and being liquid in ink at 25°C, containing a wetting agent as
the main constituent, to the total amount of the solid component in the recording ink
to a value within the range of from 1.85 to 3.10, the drying rate can be increased. As
^constituents being liquid in ink at 25°C other than water and wetting agents, which
are further added in accordance with die necessity, there are the following penetrant
and surfactant. Note that the phrase "being liquid in ink at 25°C" means that it is
liquid in an ink placed under the conditions of normal temperature and normal
pressure (25°C, 1 atmosphere). However, when the additive amount of constituents
) other than wetting agent is small and when the total amount of the liquid component
having a boiling point higher than that of water and being liquid in ink at 25°C
approximates the use amount of the wetting agent, it makes no difference.
- Penetrant -
The amount of the penetrant is calculated with the inclusion of it in the
> amount of the liquid component having a higher boiling point and being liquid in ink
at 25°C, provided that the penetrant has a higher boiling point than that of water and
being liquid in ink at 25°C.
For the penetrant, a polyol compound having 8 to 11 carbon atoms or a
glycol ether compound is used. At least any one of the polyol compound and the
i glycol ether compound has effect of accelerating the penetration to paper and
preventing the occurrence of ink bleeding and is a partially aqueous compound
having a solubility of 0.1% by mass to 4.5% by mass in water at 25°C.
Examples of the polyol compound having 8 to 11 carbon atoms include 2-
ethyl-l,3-hexanediol, and 2,2,4-trimetyl-l,3-pentanediol.

Examples of the glycol ether compound include polyhydric alcohol alkyl
ether compounds, and polyhydric alcohol aryl ether compounds.
Examples of the polyhydric alcohol alkyl ether compounds include
ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol
> monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl
ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.
Examples of the polyhydric alcohol aryl ether compounds include ethylene
glycol monophenyl ether, and ethylene glycol monobenzyl ether.
The amount of the penetrant as the liquid component having a boiling
i point higher than that of water and being liquid in ink at 25°C contained in the
recording ink is preferably 0% by mass to 10% by mass, and more preferably 0.5%
by mass to 5% by mass.
- Surfactant -
The surfactant is added in accordance with the necessity as described
above, and is calculated with the inclusion of it in the amount of the liquid
component having a higher boiling point and being liquid in ink at 25°C, provided
that the surfactant has a higher boiling point than that of water and is liquid in ink at
25°C.
The surfactant is not particularly limited and may be suitably selected from
among surfactants that will not impair the dispersion stability, in view of the
combination of the type of colorant, wetting agent and penetrant etc. used, in
accordance with the intended use. However, when printed on printing paper, it is
preferable to use a surfactant having low surface tension and high leveling property,
and at least one selected from silicone surfactants and fluorochemical surfactants is
preferable. Of these, fluorochemical surfactants are particularly preferable.
As the fluorochemical surfactant, the number of fluorine-substituted
carbon atoms is preferably 2 to 16, and more preferably 4 to 16. When the number
of fluorine-substituted carbon atoms is less than 2, the effect of fluorine may not be
obtained, and when the number exceeds 16, it may cause a problem with storage
stability of the ink.
Examples of the fluorochemical surfactants include perfluoroalkyl sulfonic
compounds, perfluoroalkyl carboxylic compounds, perfluoroalkyl phosphoric ester
compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether
polymer compounds having perfluoroalkyl ether group at side chains thereof. Of
these, polyoxyalkylene ether polymer compounds having perfluoroalkyl ether group
at side chains thereof are particularly preferable because they are free of foaming
property.
Examples of the perfluoroalkyl sulfonic compounds include perfluoroalkyl
sulfonic acids, and perfluoroalkyl sulfonic acid salts.
Examples of the perfluoroalkyl carboxylic compounds include
perfluoroalkyl carboxylic acids, and perfluoroalkyl carboxylic acid salts.
Examples of the perfluoroalkyl phosphoric ester compounds include
perfluoroalkyl phosphoric esters, and salts of perfluoroalkyl phosphoric acid.
Examples of the polyoxyalkylene ether polymer compound having
perfluoroalkyl ether group at side chains thereof include polyoxyalkylene ether
polymers having perfluoroalkyl ether group at side chains thereof, sulfate ester salts
of polyoxyalkylene ether polymers having perfluoroalkyl ether group at side chains

thereof, and salts of polyoxyalkylene ether polymers having perfluoroalkyl ether
group at side chains thereof.
Examples of counterions of salts of the fluorochemical surfactants include
Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, and NH(CH2CH2OH)3.
> For the fluorochemical surfactant, suitably synthesized one or a
commercially available product may be used.
Examples of the commercially available fluorochemical surfactant include
SURFLON S-lll, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all
manufactured by Asahi Glass Co.); FRORARD FC-93, FC-95, FC-98, FC-129, FC-
i 135, FC-170C, FC-430, and FC-431 (all manufactured by Sumitomo 3M Ltd.);
MEGAFAC F-470, F-1405, and F-474 (all manufactured by Dainippon Ink and
Chemicals, Inc.); ZONYL TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300
and UR (all manufactured by DuPont); FT-110, FT-250, FT-251, FT-400S, FT-150,
and FT-400SW (all manufactured by Neos Co.), and PF-151N (manufactured by
Omnova Co., Ltd.). Among these, FT-110, FT-250, FT-251, FT-400S, FT-150, and
FT-400SW manufactured by Neos Co. and PF-151N manufactured by Omnova Co.,
Ltd. are particularly preferable.
As specific examples of the fluorochemical surfactant, compounds
represented by the following structural formula are preferred.
(1) Anionic fluorochemical surfactant
In the structural formula, Rf represents a mixture of fluorine-containing
hydrophobic groups represented by the following structural formulas; A represents

-SO3X, -COOX or -PO3X (X is a counter anion, and specific examples thereof are
hydrogen atom, Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2 or
NH(CH2CH2OH)3.
In the structural formula, Rf' represents a fluorine-containing group
represented by the following structural formula; X is the same as described above in
meaning; n is an integer of 1 or 2; and m is an integer of 2 - n.

In the structural formula, n is an integer of 3 to 10. D

In the structural formula, each of Rf' and X is the same as described above
»
in meaning.

In the structural formula, each of Rf' and X is the same as described above
in meaning.
(2) Nonionic fluolechemical surfactant


In the structural formula, Rf is the same as described above in meaning;
and n is an integer of 5 to 20.

In the structural formula, Rf' is the same as described above in meaning;
and n is an integer of 1 to 40.
(3) Amphoteric surfactant

In the structural formula, Rf is the same as described above in meaning.
) (4) Oligomer type fluorochemical surfactant
In the structural formula, Rf" represents a fluorine-contaiinng group
represented by the following structural formula; n is an integer of 0 to 10; and X is
the same as described above in meaning.

In the structural formula, n is an integer of 1 to 4.
D In the structural formula, Rf" is the same as described above in meaning;
is an integer of 0 to 10; m is an integer of 0 to 10; and n is an integer of 0 to 10.
In the structural formula, each of R1 and R3 represents a hydrogen atom or
a fluorine-containing group; each of R2 and R4 represents a fluorine-containing
group; each of m, n, p, q, and r represents an integer; it should be noted that the
fluorine-containing groups in R1 to R4 are the same as those described in (2) or (4).
The silicone surfactant is not particularly limited and may be suitably
selected in accordance with the intended use, however, the one that has a high pH but
is not decomposed is preferable. Examples thereof include side-chain-modified
polydimethylsiloxane, both-ends modified polydimethylsiloxane, one-end modified
polydimethylsiloxane, and side-chain/both-ends modified polydimethylsiloxane. A
silicone surfactant having any of a polyoxyethylene group, a polyoxyethylene
polyoxypropylene group as a modified group is particularly preferable because it
exhibits favorable properties as an aqueous surfactant.
For the silicone surfactant, suitably synthesized one or commercial product
may be used. Such commercial products are readily available from BYK Chemie

Japan, Shin-Etsu Chemical Co., Ltd., DOW CORNING TORAY SILICONE CO.,
LTD., and Shin-Etsu Silicone Corp.
The polyether-modified silicone surfactant is not particularly limited and
may be suitably selected in accordance with the intended use. Examples thereof
include compounds in which a polyalkylene oxide structure represented by the
following structural formula is introduced to Si-bonded side chains of
dimethylpolysiloxane.
In the structural formula, each of m, n, a, and b is an integer; and each of R
and R' represents an alkyl group or an alkylene group.
For the polyether-modified silicone compound, suitably synthesized one or
a commercial product may be used. Examples of the commercially available product
include KF-618, KF-642 and KF643 (all manufactured by Shin-Etsu Chemical Co.,
Ltd.).
Besides the fiuorochemical surfactants and the silicone surfactants, anionic
surfactants, nonionic surfactants, and amphoteric surfactants may be used as well.
Examples of the anionic surfactants include polyoxyethylene alkylether
acetate salts, dodecylbenzene sulfonic acid salts, succinic acid ester sulfonic acid
salts, lauryl salts, and salts of polyoxyethylene alkyl ether sulfates.
Examples of the nonionic surfactants include acetylene glycol surfactants,
polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene
alkyl esters, and polyoxyethylene sorbitan fatty acid ester.
Examples of the acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-
decin-4,7-diol, 3,6-dimethyl-4-octine-3,6-diol, and 3,5-dimethyl-l-hexine-3-ol.
Examples of commercial products of the acetylene glycol surfactant include
SURFINOL 104, 82, 465, 485, and TG produced by Air Products Co., Ltd.
Examples of the amphoteric surfactant include laurylamino propionic acid
salts, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethyl betaine,
lauryldimethylamine oxide, myristildimethylamine oxide, stearyldimethylamine
oxide, dihydroxyethyllaurylamine oxide, polyoxyethylene coconut oil
alkyldimethylamine oxide, dimethylalkyl (coconut) betaine, and
dimethyl laury lbetaine.
For these surfactants, commercial products are readily available from
Nikko Chemicals Co., Ltd., NIHON EMULSION Co., Ltd., NIPPON SHOKUBAI
CO., LTD., Toho Chemical Industry Co., Ltd., Kao Corp., Adeka Co., Ltd., Lion
Corporation, Aoki Oil Industrial Co., Ltd., and Sanyo Chemical Industries, Ltd.
The surfactants are not particularly limited to those disclosed above, and
they may be used alone or in combination. Even when such a surfactant cannot be
readily dissolved in recording ink as singularly used, it can be dissolved and be
present stably therein when mixed with other surfactants.
Of these surfactants, those represented by any one of the following
Structural Formulas (1) to (5) are preferably used.
D R1-0-(CH2CH20 D h-R2 D D Structural Formula (1)

In Structural Formula (1), R1 represents an alkyl group that may be
branched, having from 6 to 14 carbon atoms or a perfluoroalkyl group that may be
branched, having from 6 to 14 carbon atoms; R2 represents a hydrogen atom or an
alkyl group that may be branched, having from 1 to 4 carbon atoms; and h is an
> integer of 5 to 20.
D R'-COCKCHzCHzOV-ien Structural Formula (2)
In Structural Formula (2), R1 represents an alkyl group that may be
branched, having from 6 to 14 carbon atoms; R2 represents a hydrogen atom or an
alkyl group that may be branched, having from 1 to 4 carbon atoms; and h is an
integer of 5 to 20.
In Structural Formula (3), R3 represents a hydrocarbon group, for example,
an alkyl group that may be branched, having from 6 to 14 carbon atoms is
exemplified; and k is an integer of 5 to 20.
CH3
R4_o_ (CH2CH20) L- (CH2CH20) p-H Structural Formula (4)
In Structural Formula (4), R4 represents a hydrocarbon group such as an
alkyl group that may be branched, having from 6 to 14 carbon atoms; L is an integer
of 5 to 10; p is an integer of 5 to 20; propylene glycol chain(s) and ethylene glycol
chain(s) may be polymerized in block or at random.
In Structural Formula (5), each of q and r is an integer of 5 to 20.
The amount of the surfactant contained in the recording ink is preferably
0.01% by mass to 3.0% by mass, and more preferably 0.5% by mass to 2% by mass.
However, the total amount of the liquid component having a boiling point higher
than that of water and being liquid in ink at 25°C is 20% by mass or less and more
preferably 15% by mass or less. When the amount of the surfactant is less than
0.01% by mass, the effect of adding the surfactant may sometimes be impaired, and
when more than 3.0% by mass, the permeation property of the ink to a recording
medium becomes higher than necessary, which may lead to a degradation in image
density and the occurrence of ink strike-through.

The total amount of the resin component contained in the solid component
is preferably 40% by mass or more and 95% by mass or less to the solid component
containing a colorant and a resin and being solid in ink at 25°C. When the amount
of the resin component is less than 40% by mass, the fixing ability and the glossiness
of the colorant may be degraded. Meanwhile, to increase the image density to some
extent, 5% by mass or more of the colorant is necessary to the total amount of the
solid component.

The reason why the amount of the resin component is large in the solid
component in this way is to improve the fixing ability, the image sharpness and the
glossiness.
Here, the resin component is a polymeric solid component other than
colorant molecules having color-developing groups, and includes resins that wrap
around the colorant and/or make the colorant dispersed. Further, the resin
component also includes a resin emulsion that is added when necessary.
It should be noted that the phrase "being solid in ink at 25°C" means that it
is solid in an ink placed under the conditions of normal temperature and normal
pressure (25°C, 1 atmosphere), the environment used in common inkjet printing.
- Resin -
The resin is not particularly limited and may be suitably selected in
accordance with the intended use as long as it is solid in ink at 25°, however, it is
preferably resin fine particles from the perspective that a large amount of resin can
be added.
For the resin fine particles, resin fine particles being present as a resin
emulsion, in a state of being dispersed in water as a continued phase are used in
production of ink. The resin emulsion may contain a dispersant such as surfactant
when necessary.
The amount of resin fine particles as the component having a dispersed
phase (the amount of resin fine particles contained in the resin emulsion solution: it
is not the amount of resin fine particles in a produced recording ink) is preferably
10% by mass to 70% by mass.
For the particle diameter of the resin fine particles, in view of being used
particularly in an inkjet recording apparatus, the volume average particle diameter
thereof is preferably 10 nm to 1,000 nm, and more preferably 100 run to 300 nm.
This particle diameter is a particle diameter in a resin emulsion, however, in the case
of being in a stable recording ink, it makes no difference between the particle
diameter in a resin emulsion and the particle diameter in a recording ink. The larger
the volume average particle diameter, the more the additive amount of the emulsion
can be increased. When the volume average particle diameter is smaller than 100
nm, the additive amount of the emulsion may not sometimes be increased, and when
the volume average particle diameter is larger than 300 nm, the reliability may
sometimes degrade. However, a resin emulsion having a particle diameter outside
the range may be possibly used. This is general tendency and does not depend upon
the type of emulsion.
The volume average particle diameter can be measured using, for example,
a particle size analyzer (MICROTRACK MODEL UPA9340, manufactured by
NIKKISO CO., LTD.).
Specifically, an emulsion aqueous solution was diluted to within the
optimum range for signal level, and the transparency was set to "Yes", and the
following provisional conditions were set: refractive index-1.49; partial density:
1.19; spherical particles-Yes; and medium-water. Herein, the volume average
particle diameter was set to a value of 50%.
The resin fine particles with the dispersed phase are not particularly
limited and may be suitably selected in accordance with the intended use. Examples
thereof include urethane resins, polyester resins, acrylic resins, vinyl acetate resins,

styrene resins, butadiene resins, styrene-butadiene resins, vinyl chloride resins,
acrylic styrene resins, and acrylic silicone resins.
For the resin emulsion, suitably synthesized one or a commercially
available product may be used.
Examples of the commercially available resin emulsions are MICROGEL
E-10O2 and E-50O2 (styrene-acrylic resin emulsion, manufactured by Nippon Paint
Co., Ltd.), BONCOAT 4001 (acrylic resin emulsion, manufactured by Dainippon Ink
and Chemicals, Inc.), BONCOAT 5454 (styrene-acrylic resin emulsion,
manufactured by Dainippon Ink and Chemicals, Inc.), SAE-1014 (styrene-acrylic
resin emulsion, manufactured by Nippon Zeon Company Limited), CYBINOL SK-
200 (acrylic resin emulsion, manufactured by Saiden Chemical Co., Ltd.), PRIMAL
AC-22 and AC-61 (acrylic resin emulsion, manufactured by Rohm & Haas Japan
K.K.), NANOCRYL SBCX-2821 and 3689 (acrylic silicone resin emulsion,
manufactured by Toyo Ink Mfg. Co., Ltd.), and #3070 (methyl methacrylate polymer
resin emulsion, manufactured by Mikuni Color Ltd.). Of these, acrylic silicone
emulsions are particularly preferable from the viewpoint of its excellence in fixing
ability.
The glass transition temperature of the resin component in the acrylic
silicone emulsion is preferably 25°C or lower,
and more preferably 0°C or lower. When the glass transition temperature is higher
than 25°C, the resin itself becomes brittle, resulting in a cause of degradation in
fixing ability. Particularly when used on printing paper having smooth surface and
hardly absorbs water, the fixing ability may possibly degrade. However, a resin
component having a glass transition temperature of 25°C or higher may be possibly
used.
Here, the glass transition temperature can be measured using, for example,
a differential scanning calorimeter (manufactured by Rigaku Denki Co., Ltd.).
Specifically, a resin film sample piece obtained by drying a resin emulsion aqueous
solution at normal temperature was heated from a temperature near -50°C, and the
glass transition temperature was determined based on a temperature at which the
resin film sample piece had an uneven portion.
- Colorant -
The colorant is not particularly limited as long as it is solid in an ink at
25°, and any of pigment and dye can be suitably used.
When a pigment is used as the colorant, an ink with excellence in light
resistance can be obtained. The pigment is not particularly limited, and commonly
pigments used for inkjet recording are used. For example, the following pigments
are preferably used:
(1) pigment having a hydrophilic group on its surface
(2) polymer emulsion pigment containing a water-insoluble or substantially water-
insoluble coloring material in a polymer fine particle
(3) microcapsulated pigment in which a pigment is covered with a resin having a
hydrophilic group
The pigment (1) is a pigment whose surface is modified so that at least one
hydrophilic group is bonded to the surface directly or via other atomic group. For
the surface modification, a method of chemically bonding a specific functional group
(functional groups such as sulfone group and carboxyl group) to the surface, a

method of subjecting the surface to a wet-process oxidation treatment using at least
any one of a hypohalous acid and salt thereof, or the like may be used. Among these
pigments, an embodiment is particularly preferable in which a carboxyl group is
bonded to the surface of the pigment and the pigment is dispersed in water. Since
the surface of the pigment is modified and a carboxyl group is bonded thereto in this
way, the dispersion stability is improved. Besides, high-quality image print can be
obtained and the water resistance of printed recording medium is further improved.
Since an ink according to this embodiment is excellent in
re-dispersibility, it allows for performing excellent printing with simple cleaning
operation, without causing the occurrence of nozzle clogging even when printing
operation is stopped for a long time and the moisture content of the ink near
nozzles of an inkjet head evaporates.
The volume average particle diameter of the self-dispersible type
pigment in ink is preferably 0.01 |im to 0.16 |im.
For example, as a self-dispersible type carbon black, those having
ionicity are preferable, and anionicly charged ones and cationicly charged ones are
more suitable.
Examples of the anionic hydrophilic group are -COOM-, -SO3M-,
-PO3HM-, -PO3M2-, -SO2NH2-, and -SO NHCOR (M represents any one of a
hydrogen atom, an alkaline metal, ammonium, and organic ammonium; R represents
any one of an alkyl group having 1 to 12 carbon atoms, a phenyl group that may
have a substituent, and a naphthyl group that may have a substituent). Among these
pigments, a color pigment with -COOM- and/or -SO3M- bonded to a surface of the
color pigment is preferably used.

For "M" in the hydrophilic group as the alkaline metal, lithium, and
potassium are exemplified. For "M" in the hydrophilic group as the organic
ammonium, monomethyl to trimethyl ammoniums, monoethyl to triethyl
ammoniums, and monomethanol to trimethanol ammoniums are exemplified. With
respect to the method of obtaining the anionicly charged color pigment, as a method
of introducing -COONa to a surface of a color pigment, for example, a method of
subjecting the color pigment to an oxidation treatment with hypochlorous soda;
julfonation method, and a method of reacting with diazonium salt are exemplified.
For the cationic hydrophilic group, quaternary ammonium group is
preferable, the following quaternary ammonium groups are more preferable. In the
jresent invention, a compound with any one of these groups is bonded to a surface
of carbon black is suitably used as a coloring material.
A method of producing a cationic self-dispersible type carbon black with a
hydrophilic group bonded to the surface thereof is not particularly limited and may

be suitably selected in accordance with the intended use. For example, as a method
of bonding an N-ethylpyridyl group represented by the following Structural Formula
to the surface of the carbon black, a method of treating carbon black with 3-amino-
N-ethylpyridium bromide is exemplified.

The hydrophilic group may be bonded to the surface of the carbon black
via other atomic group. Examples of the other atomic group include alkyl groups
having 1 to 12 carbon atoms, phenyl groups that may have a substituent or naphthyl
groups that may have a substitutent. Specific example of the case where the
hydrophilic group is bonded to the surface of carbon black via other atomic group
are -C2H4COOM (M represents an alkaline metal or a quaternary ammonium),
-PhSC^M (Ph represents a phenyl group, M represents an alkaline metal or a
quaternary ammonium), and -CsHioNrV.
For the pigment (2), the polymer emulsion containing a coloring material
means at least any one of a polymer emulsion with a pigment included in polymer
fine particles and a polymer emulsion in which a pigment is adsorbed to the surface
of polymer fine particles. Examples thereof include those described in Japanese
Patent Application Laid-Open (JP-A) No. 2001-139849.
In this case, all the pigment particles are not necessarily included in or
adsorbed to polymer fine particles, and the pigment may be dispersed in the
emulsion within the range where the effects of the present invention are not
impaired.
The phrase "water-insoluble or substantially water-insoluble" means that
10 parts by mass or more of the coloring material are not dissolved to 100 parts by
mass of water at 20°C. The word "dissolved" means that separation of the coloring
material and/or sedimentation of the coloring material is not visually observed on the
surface layer of the aqueous solution or the bottom layer thereof.
The polymer constituting the polymer emulsion is not particularly limited
and may be suitably selected in accordance with the intended use. Examples of the
polymer include vinyl polymers, polyester polymers, polyurethane polymers, and
polymers disclosed in Japanese Patent Application Laid-Open (JP-A) Nos. 2000-
53897 and 2001-139849. Of these, vinyl polymers, and polyester polymers are
particularly preferable.
The volume average particle diameter of polymer fine particles (colorant
fine particles) containing the coloring material in the ink is preferably 0.01 u,m to
0.16 µm.
When the pigment (2) is used, an ink which is excellent in light resistance
and fixing ability can be obtained.
In the pigment (3), a pigment is dispersed in water by covering the
pigment with a hydrophilic water-insoluble resin to make a resin layer on the surface
of the pigment have hydrophilic properties. Examples thereof include those
i described in Japanese Patent Application Laid-Open (JP-A) No. 20O2-67473.
When the pigment (3) is used, an ink which is excellent in light resistance
and fixing ability can be obtained.
It is considered that the pigments (2) and (3) are similar to each other in
terms that a pigment and a resin are integrated into one compound. Any one of the
pigments (2) and (3) can be suitably used in the present invention.
When any of the pigments (1), (2), and (3) is made to have an ink
composition ratio according to the present invention, the improvements in drying
and high-color tone property are remarkably exhibited.
The color-developing component of the colorant is not particularly limited
and may be suitably selected in accordance with the intended use. For example, the
color-developing component may be any of an inorganic pigment and an organic
pigment.
Examples of the inorganic pigment include titanium oxide, iron oxide,
calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium
red, chrome yellow, and carbon black. Of these, carbon black etc. are preferable.
Examples of the carbon black are those produced by known methods such as the
contact method, furnace method, thermal method.
Examples of the organic pigment include azo pigments, polycyclic
pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Of
these, azo pigments and polycyclic pigments are more preferable. Examples of the
«
azo pigments include azo lake, insoluble azo pigments, condensed azo pigments, and
chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine
pigments, perylene pigments, perinone pigments, anthraquinone pigments,
quinacridone pigments, dioxadine pigments, indigo pigments, thioindigo pigments,
isoindolinone pigments, and quinophthalone pigments. Examples of the dye chelates
include basic dye type chelates, acidic dye type chelates.

The color of the pigment is not particularly limited and may be suitably
selected in accordance with the intended use. For example, pigments for black color,
and pigment for color ink are exemplified. These pigments may be used alone or in
combination.
Examples of the pigments for black color include carbon black (C.I.
Pigment Black 7) such as furnace black, lamp black, and channel black; metal
pigments such as copper and iron (C.I. Pigment Black 11), titanium oxide, etc.; and
organic pigments such as aniline black (C.I. Pigment Black 1).
As the pigments for color ink, examples of yellow color pigments include
C.I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 23,
24, 34, 35, 37, and 42 (yellow iron oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 95
97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 150, and 153.
Examples of magenta color pigments include C.I. Pigment Red 1, 2, 3, 5,
17, 22 (Brilliant Fast Scarlet), 23, 31, 38, 48:2 (Permanent Red 2B (Ba)), 48:2
(Permanent Red 2B (Ca)), 48:3 (Permanent Red 2B (Sr)), 48:4 (Permanent Red 2B
(Mn)), 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81
(Rhodamine 6GLake), 83, 88, 92, 101 (colcothar), 104, 105, 106, 108 (cadmium
red) 112, 114, 122 (dimethyl quinacridone), 123, 146, 149, 166, 168, 170, 172, 177,
178, 179, 185, 190, 193, 209, and 219.
Examples of cyan color pigments include C.I. Pigment Blue 1,2, 15
(copper phthalocyanine blue R), 15:1, 15:2, 15:3 (phthalocyanine blue G), 15:4, 15:6
(phthalocyanine blue E), 16, 17:1, 56, 60, and 63.
Further, examples of neutral color pigments such as red, green blue colors
include C.I. Pigment Red 177, 194, 224; C.I. Pigment Orange 43; C.I. Pigment
Violet 3, 19, 23, 37; and C.I. Pigment Green 7, and 36.
When a dye is used as the colorant, an ink which is excellent in color tone
can be obtained. Examples of the dye include oil-soluble dyes, and dispersed dyes.
In the recording ink, it is preferable that the resin component be 40% by
mass to 95% by mass to the total amount of the solid component (for example, the
total amount of a resin and a colorant used). Therefore, the amount of the colorant
contained in the solid component is preferably 60% by mass or less. In the resin
component based on the calculation at this point, the amount of resin covering the
colorant used is also included. More specifically, the total amount of the resin
components including resins covering the colorant used is 40% by mass or more
among the total solid component that is equal to the amount of resin plus the amount
of the colorant.
The other components are not particularly limited and may be suitably
selected in accordance with the necessity. Examples thereof include antifoaming
agent, antiseptic/antifungal agent, anti-corrosive agent, pH adjuster, specific
resistivity adjuster, antioxidant, ultraviolet absorber, oxygen absorbent, light
*
stabilizer, and viscosity adjuster.
The antifoaming agent is not particularly limited and may be suitably
selected in accordance with the intended use. For example, silicone antifoaming
agents, polyether antifoaming agents, fatty acid ester antifoaming agents are
preferably exemplified. These antifoaming agents may be used alone or in
combination. Of these, silicone antifoaming agents are preferable in terms of the
excellence in foam breaking effect.
Examples of the silicone antifoaming agents include oil type silicone
antifoaming agents, compound type silicone antifoaming agents, self-emulsified type
. silicone antifoaming agents, emulsion type silicone antifoaming agents, and
modified silicone antifoaming agents. Examples of the modified silicone
antifoaming agents include amino-modified silicone antifoaming agents, carbinol-
modified silicone antifoaming agents, methacryl-modified silicone antifoaming
agents, polyether-modified silicone antifoaming agents, alkyl-modified silicone
antifoaming agents, fatty acid ester-modified silicone antifoaming agents, and
alkylene oxide-modified silicone antifoaming agents. Of these, self-emulsified
silicone antifoaming agents, and emulsion-type silicone antifoaming agents etc. are
preferable in view of the use thereof in the recording ink, which is an aqueous
medium.
For the antifoaming agent, a commercially available product may be used.
Examples of the commercial product include silicone antifoaming agents
manufactured by Shin-Etsu Silicone Corp. (KS508, KS531, KM72, KM85, etc.);
silicone antifoaming agents manufactured by DOW CORNING TORAY SILICONE
CO., LTD. (Q2-3183A, SH5510, etc.); silicone antifoaming agents manufactured by
Nippon Unicar Co., Ltd. (SAG30, etc.); and antifoaming agents manufactured by
Asahi Denka Co., Ltd. (ADECANATE series, etc.).
The amount of the antifoaming agent contained in the recording ink is not
particularly limited and may be suitably selected in accordance with the intended
use. For example, it is preferably 0.001% by mass to 3% by mass, and more
preferably 0.05% by mass to 0.5% by mass.
Examples of the antiseptic/antifungal agent include 1,2-
benzoisothiazoline-3-on, dehydrosodium acetate, sodium sorbate, 2-pyridinethiol-l-
j sodium oxide, sodium benzoate, and sodium pentachlorophenol.
Examples of the specific resistivity adjuster include mineral salts, for
example, by adding an alkaline metal halide or ammonium halide (such as lithium
chloride, ammonium chloride, sodium chloride) to the ink composition, it is possible
to prepare a recording liquid used in an inkjet recording method where a recording
) ink is charged.
The pH adjuster is not particularly limited, and an arbitrarily selected
material can be used as long as the pH can be adjusted to 7 or higher without
adversely affecting the ink prepared. Examples thereof include amines such as
diethanol amine, triethanol amine; hydroxides of alkaline metal elements such as
> lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonates of
alkaline metals such as ammonium hydroxide, quaternary ammonium hydroxide,
quaternary phosphonium hydroxide, lithium carbonate, sodium carbonate, and
potassium carbonate; and aminopropanediol derivatives.
The aminopropanediol derivative is a water-soluble organic basic
) compound, and examples thereof include l-amino-2,3-propanediol, 1-methylamino-
2,3-propanediol, 2-amino-2-methyl-1,3-propanediol, and 2-amino-2-ethy 1-1,3-
propanediol.
Examples of the anti-corrosive agent include acid sulfite salts, sodium
thiosulfates, ammon thioglycolates, diisopropyl ammonium nitrites, pentaerythritol
tetranitrates, and dicyclohexyl ammonium nitrites.
Examples of the antioxidant include phenol antioxidants (including
> hindered phenol antioxidants), amine antioxidants, sulfur antioxidants, and
phosphate antioxidants.
Examples of the phenol antioxidants (including hindered phenol
antioxidants) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol,
stearyl-p-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis(4-
)methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-
butylidenebis(3-metnyl-6-tert-butylphenol), 3,9-bis[l,l-dimethyl-2[|3-(3-tert-butyl-4-
hydroxy-5-methylphenyl) propionyloxy]ethyl]2,4,8,10-tetra-oxaspiro[5,5]undecane,
1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-
tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene, and tetrakis[methylene-3-(3',5'-di-
tert-butyl-4'-hydroxyphenyl)propionate]methane.
Examples of the amine antioxidants include phenyl-|3-naphthylamine, a-
naphthylamine, N,N'-di-sec-butyl-p-phenylenediamine, phenothiazine, N,N'-
diphenyl-p-phenylenediamine, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol,
2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2'-methylenebis(4-methyl-
6-tert-buthylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-
methyl-6-tert-butylphenol), tetrakis[methylene-3(3,5-di-tert-butyl-4-
dihydroxyphenyl) propionate] methane, and l,l,3-tris(2-methyl-4-hydroxy-5-tert-
butylphenyl) butane.
Examples of the sulfur antioxidants include dilauryl-3,3'-thiodipropyonate,
distearylthiodipropyonate, laurylstearylthiodipropyonate, dimyristyl 3,3'-
thiodipropyonate, distearyl ß,ß'-thiodipropyonate, 2-mercaptobenzoimidazole, and
dilauryl sulfide.
Examples of the phosphate antioxidants include triphenyl phosphide,
octadecyl phosphide, triisodecyl phosphide, trilauryl trithiophosphide, and
trisnonylphenylphosphide.
Examples of the ultraviolet absorbers include benzophenone ultraviolet
absorbers, benzotriazole ultraviolet absorbers, salicylate ultraviolet absorbers,
cyanoacrylate ultraviolet absorbers, and nickel complex salt ultraviolet absorbers.
Examples of the benzophenone ultraviolet absorbers include 2-hydroxy-4-
n-octoxybenzophenone, 2-hydroxy-4-n-dedecyloxybenzophenone, 2,4-
dihydroxybenzophenoene, 2-hydroxy-4-methoxybenzophenone, and 2,2',4,4'-
tetrahydroxybenzophenone.
Examples of the benzotriazole ultraviolet absorbers include 2-(2'-hydroxy-
5-tert-octylphenyl) benzotriazole, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-
(2'-hydroxy-4'-octoxyphenyl) benzotriazole, and 2-(2'-hydroxy-3'-tert-butyl-5'-
methylphenyl)-5-
chlorobenzotriazole.
Examples of the salicylate ultraviolet abosorbers include phenylsalicylate,
p-tert-butylphenylsalicylate, and p-octylphenylsalicylate.
Examples of the cyanoacrylate ultraviolet absorbers include ethyl-2-cyano-
3,3'-diphenylacrylate, methyl-2-cyano-3-methyl-3-(p-methoxyphenyl) acrylate, and
butyl-2-cyano-3-methyl-3-(p-methoxyphenyl) acrylate.

Examples of the nickel complex salt ultraviolet absorbers include
nickelbis(octylphenyl) sulfide, 2,2'-thiobis(4-tert-octylphelate)-n-butylaminenickel
(II), 2,2'-thiobis(4-tert-octylphelate)-2-ethylhexylaminenickel (II), and 2,2'-
thiobis(4-tert-octylphelate) triethanolaminenickel (II).
The recording ink of the present invention is produced by dispersing or
dissolving in an aqueous medium a solid component containing a colorant and a
resin and being solid in ink at 25°C, and a liquid component having a boiling point
higher than that of water and being liquid in ink at 25°C, water and other
components in accordance with the necessity, and further agitating and mixing these
components when necessary. It should be noted that the colorant and the resin are
preliminarily dissolved or dispersed in water to prepare a solution or dispersion
liquid, and the solution or dispersion liquid is used. The dispersion treatment can be
carried out by means of a sand mill, homogenizer, ball mill, paint shaker, ultrasonic
dispersing device, or the like. The agitation/mixing can be carried out by means of
an agitator using common stirring blades, a magnetic stirrer, a high-speed dispersing
device, or the like.
- Measurement method of solid component amount and liquid component amount -
The amount of the solid component that is solid in ink at 25°C and the
amount of the liquid component that is liquid in ink at 25°C can be measured by
calculation, provided that the formulation of the ink has been known. When the
formulation of the ink is unclear, the amounts thereof can be measured, for example,
by separating only the solid component from the ink. For example, an ink sample is
centrifugalized at 500,000 G or higher at room temperature (25°C) for 24 hours to
precipitate a solid component in the ink sample, thereby the separation between solid

phase and liquid phase can be achieved. Further, depending on the type of colorant
and the type of the water-dispersible resin used, the solid-liquid separation can be
done by a salting-out method or an agglomeration method using a solvent, and the
solid component separeated out is then dried for use in measurement,
i When a pigment is used as the colorant, the ratio between the colorant and
the resin can be determined based on the reduction rate of the mass obtained by a
thermal mass analysis. During the measurement, to prevent the resin and the
pigment from burning, the temperature of the ink sample is increased to 500°C at an
increasing rate of 10°C/min under an inert gas atmosphere, and then a change in
mass is measured. Since a slight amount of moisture content and wetting agent
component still remains in the solid matter after the separation between solid phase
and liquid phase, the mass of the solid matter determined at a temperature of 200°C
where almost all the moisture content and wetting agent has evaporated is defined as
the total mass of the solid matter, the mass of the solid matter determined at a
temperature of 500°C where a large amount of the resin has thermally decomposed
and evaporated is defined as the mass of the pigment, and the ratio between the mass
of the pigment and the mass of the resin can be measured based upon the following
mathematical expression.
Mass of pigment/(total mass of solid matter - mass of pigment)
Further, when a certain pigment with low heat resistance such as azo
pigment is used, the pigment has thermally decomposed by the time the temperature
reaches 500°C, and thus it is difficult to measure the amount of the pigment.
However, the amount of the pigment can be measured by making the resin
component dissolved in a solvent to extract the solid matter from the solvent. Based

on the mass of the ink sample before/after the extraction, the rate of the amount of
the pigment contained in the solid matter is determined, and the total mass of the
solid matter is determined by a thermal mass analysis. Thereafter, the mass of the
pigment in the solid matter can be measured by the use of the expression, the mass of
the ink sample is multiplied by the rate of the amount of the pigment.
When the molecular structure of the colorant used is clearly determined,
the amount of the solid content of the colorant can be measured by the following
manner. When a pigment or a dye is used as a colorant, the amount of the solid
content of the colorant can be measured by a nuclear magnetic resonance analysis
(NMR). When an inorganic pigment with heavy metal atom contained in its
molecular frame, a metal-containing organic pigment, or metal-containing dye is
used as a colorant, the amount of the solid content of the colorant can be measured
by a fluorescent X-ray analysis.
The qualitative analysis and quantitative analysis on a liquid component
can be carried out by gas chromatography analyses (GC, BC-AED, etc.).
Physical properties of the recording ink of the present invention are not
particularly limited and may be suitably selected in accordance with the intended
use. For example, the viscosity, surface tension, pH etc. are preferably within the
following ranges.
The viscosity of the recording ink is preferably 10 mPa-s or less at 25°C,
and more preferably 7 mPa-s or less at 25°C. When the viscosity is higher than 10
mPa-s, it may become difficult to ensure the ejection stability, and the drying
property may degrade. However, such an ink having high-viscosity may be possibly
used depending upon the structure of the inkjet head.

The surface tension of the recording ink at 25°C is preferably 35 mN/m or
lower, and more preferably 30 mN/m or lower. When the surface tension is higher
than 35 mN/m, ink leveling is least likely to take place on a recording medium,
leading to longer time required for drying.
The recording ink preferably has a pH of 7 to 10.
The color of the recording ink of the present invention is not particularly
limited and may be suitably selected in accordance with the intended use. For
example, yellow, magenta, cyan, black are exemplified. When recording is
performed using two or more colors of them in combination, a multi-color image can
be recorded, and when recording is performed using all of these colors as an ink set,
a full-color image can be recorded.
The recording ink of the present invention can be suitably used in printers
each equipped with an inkjet head such as a so-called "piezo-type inkjet head" in
which a vibrating plate constituting the wall surface of an ink flow passage is
deflected by using an piezoelectric element as a pressure generating unit that is
configured to pressurize an ink contained in an ink flow passage, the volume inside
the ink flow passage is changed to thereby eject ink droplets (see Japanese Patent
Application Laid-Open (JP-A) No. 2-51734); a so-called "thermal-type inkjet head"
in which an ink is heated with a thermal energy in an ink flow passage using a heat
generating resistor to generate gas bubbles (see Japanese Patent Application Laid-
Open (JP-A) No. 61-59911); and a so-called "electrostatic type inkjet head" in which
a vibrating plate constituting the wall surface of an ink flow passage is placed at a
position opposed to electrodes, the volume inside the ink flow passage is changed by
deflecting the vibrating plate by an electrostatic force generated between the

vibrating plate and the electrodes to thereby eject ink droplets (see Japanese Patent
Application Laid-Open (JP-A) No. 6-71882).
The recording ink of the present invention can be suitably used in various
fields, and can be suitably used in image recording apparatuses (printers, etc.) based
upon inkjet recording method. For example, the recording ink can be used in
printers etc. having a function of heating paper to be recorded and the recording ink
at a temperature of 50°C to 200°C during printing or before/after printing to thereby
accelerate fixing of print to the paper, and can be particularly suitably used in the
following ink cartridge, ink recorded matter, inkjet recording apparatus, and inkjet
recording method of the present invention.
(Ink cartridge)
The ink cartridge of the present invention has a container to accommodate
the recording ink of the present invention and futher has other members suitably
selected in accordance with the necessity.
The container is not particularly limited, and the shape, structure, size,
material and the like may be suitably selected in accordance with the intended use.
For example, a container having at least an ink bag formed of an aluminum laminate
film, a resin film, etc. is preferably exemplified.
Hereinafter, the ink cartridge will be described with reference to FIGS. 1
and 2. FIG. 1 is a diagram showing one example of an ink cartridge 10 according to
the present invention, and FIG. 2 is a diagram exemplarily showing the ink cartridge
shown in FIG. 1 with the inclusion of a case (exterior case).
The ink cartridge 10 is, as shown in FIG. 1, filled with an ink from an ink
inlet port 42 to an ink bag 41, the gas contained therein is evacuated, and the ink

inlet port 42 is closed by heat sealing. During the use of the ink, the ink bag 41 is
pricked at an ink ejection port 43 composed of a rubber member with a needle
provided on the main body of a printer, thereby supplying the ink to the printer.
The ink bag 41 is formed of a wrapping member such as aluminum
laminate film allowing for free air permeability. The ink bag 41 is, as shown in FIG.
2, housed in a cartridge case 44 that is usually made of plastic and is detachably
mounted to various types of inkjet recording apparatuses.
(Inkjet recording apparatus and inkjet recording method)
The inkjet recording apparatus of the present invention has at least an ink
jetting unit, and further has other units suitably selected in accordance with the
necessity, for example, a stimulus generating unit, a controlling unit, and the like.
The inkjet recording method of the present invention includes at least an
ink jetting step, and further includes other steps suitably selected in accordance with
the necessity, for example, a stimulus generating step, a controlling step, and the
like.
The inkjet recording method of the present invention can be suitably
carried out by the inkjet recording apparatus of the present invention. The ink jetting
step can be suitably carried out by the ink jetting unit. The other steps can be
»
suitably carried out by the other units.
- Ink jetting step and ink jetting unit -
The ink jetting step is a step of forming an image by applying a stimulus to
the recording ink of the present invention so as to jet the recording ink.
The ink jetting unit is a unit configured to jet the recording ink of the
present invention by applying a stimulus to the recording ink so as to form an image.

The ink jetting unit is not particularly limited and may be suitably selected in
accordance with the intended use. For example, as the ink jetting unit, various types
of recording heads (ink ejection heads) are exemplified. In particular, an ink jetting
unit having a head provided with a plurality of nozzle rows and a sub tank to house a
> liquid supplied from a liquid storage tank and to supply the liquid to the head, is
preferable.
The sub tank preferably has a negative pressure generating unit configured
to generate a negative pressure in the sub tank, an air releasing unit configured to
release air in the sub tank, and a detecting unit configured to detect the presence or
i absence of ink depending on a difference in electric resistivity.
The stimulus can be generated by, for example, the stimulus generating
unit. The stimulus is not particularly limited and may be suitably selected in
accordance with the intended use. Examples thereof include heat (temperature),
pressure, vibration, and light. These may be used alone or in combination. Of these,
i heat, and pressure are preferred.
Examples of the stimulus generating unit include heater, pressurizer,
piezoelectric element, vibration generating device, ultrasonic oscillator, and light.
Specifically, as the stimulus generating unit, the following are exemplified: a
»
piezoelectric actuator such as a piezoelectric element; a thermal actuator that uses a
thermoelectric conversion element such as heat-generating resistor and employs
phase transition caused by film boiling of a liquid; a shape memory alloy actuator
that uses a metal phase transition caused by temperature variations, or an
electrostatic actuator using electrostatic forces.
An aspect of the jetting of the recording ink is not particularly limited and
varies depending on the type of the stimulus. For example, when the stimulus is
"heat", there is a method in which the recording ink in the recording head is given
heat energy in accordance with a recording signal by the use of a thermal head, for
example, to generate air bubbles in the recording ink by the heat energy, thereby the
recording ink is ejected and jetted as liquid droplets from nozzle holes of the
recording head. When the stimulus is "pressure", there is a method in which a
voltage is applied to a piezoelectric element which is bonded at a place called
pressure chamber in the ink flow passage in a recording head, thereby the
piezoelectric element bends, the inner volume of the pressure chamber is reduced,
thereby the recording ink is ejected and jetted as liquid droplets from nozzle holes of
the recording head.
The method of jetting a recording ink by applying a voltage to a
piezoelectric element is preferred. The piezo method is advantageous in jetting an
ink containing resin components, and is an effective method which causes less
nozzle clogging particularly when an ink containing less amount of wetting agent is
used.
Further, in order to prevent nozzles from coming off, it is preferable that a
piezoelectric element be applied with a voltage having an intensity by which the ink
is not ejected, and the operation of scanning the recording head be performed
without ejecting an ink from the recording head. Further, it is preferable that the
operation of ejecting ink droplets in an ink reservoir be performed before the
recording head has performed idle scanning operation for one page.
Further, the ink jetting unit preferably has a scraping-off unit configured to
scrape off an ink that adheres on an idle ejection receiver. As the scraping-off unit,
any one of a wiper and a cutter is preferable.
The controlling unit is not particularly limited and may be suitably
selected in accordance with the intended use, as long as it is capable of controlling
the operations of the units described above. Examples of the controlling unit include
instruments such as a sequencer and computer.
Here, it is preferable that in the ink jetting unit, on a plate surface of the
inkjet head for jetting an ink, with ink ejection ports provided thereon, an ink
repellent layer be provided.
The surface roughness (Ra) of the ink repellent layer is preferably 0.2 urn
or less. By adjusting the surface roughness (Ra) of the ink repellent layer to 0.2 µm
or less, unwiped portions can be reduced.
FIGS. 13, 14A to 14C are cross-sectional views of a nozzle plate
used in the present invention.
In this embodiment, a nozzle plate 232, which serves as a plate base of an
inkjet head, is produced by an Ni electrocasting. On a surface of the nozzle plate
232, an ink repellent layer 231 is formed, which is a silicone resin film having a
thickness of 1 angstrom (0.1 nm) or more. The surface roughness (Ra) of the ink
repellent layer 231 is preferably 0.2 µm or less, and the thickness of the ink repellent
layer 231 is preferably 0.1 µm or more, and more preferably 0.5 µm or more.
When the inkjet head is filled with an ink, as shown in FIG. 14C, a
meniscus (liquid surface) P is formed at a boundary portion between the ink repellent
layer 231 formed of a silicone resin film and the nozzle plate 232.

The ink ejection ports are formed on the inkjet head such that the cross-
section area of each of the ink ejection ports measured at a plane, which is
perpendicular to a center line of each of the ink ejection ports in the ink repellent
layer formed near each of ink ejection ports on the plate surface on which a plurality
>of the ink ejection ports (nozzles) for ejecting ink are provided, gradually becomes
larger with distance from the surface of the plate base.
The shape of of the ink repellent layer near each of the ink ejection ports is
preferably a rounded surface. Further, it is preferable that the curvature radius of a
curved line of the ink repellent layer near each of the ink ejection ports, measured at
a plane including the center line of each of the ink ejection ports, be larger than the
thickness of the ink repellent layer.
Further, it is preferable that a curved line of the ink repellent layer, formed
from the outside edge of each of the ink ejection ports of the ink repellent layer to a
portion near each of the ink ejection ports at a cross-section as a plane including the
center line of each of the ink ejection ports be a substantially circular-arc curved line,
and the curvature radius of the circular arc be larger than the thickness of the ink
repellent layer.
Furthermore, it is preferable that a tangent line of the ink repellent layer
that passes the outside edge of each of the ink ejection ports of the ink repellent
layer, at the cross-section as a plane including the center line of each of the ink
ejection ports be formed with an angle less than 90 degrees with respect to the
surface of the nozzle member including the outside edge thereof.
Ports of the nozzle plate 232 are provided such that a cross-section thereof
measured at a plane perpendicular to the center line represented with an alternate

long and short dash line in FIGS. 14Ato 14C is substantially circular, centering on
the center line. Further, the ink repellent layer 231 formed on the ink ejection
surface of the nozzle plate 232 is formed such that the cross-sectional area of each of
the ports (each of the openings) measured at a plane perpendicular to the center line
gradually becomes larger with distance from the nozzle plate 232.
More specifically, as shown in FIG. 14A, in each of the ports of the ink
repellent layer 231, a curved line formed from the outside edge of one port (here,
each of the ports is explained as one port for convenience) in the nozzle plate 232 to
a portion near the port is formed in a round shape with a curvature radius "r". The
curvature radius r is preferably larger than the thickness "d" of the ink repellent layer
231 other than the vicinity of the port.
The thickness d is a thickness of portions of the ink repellent layer 231
other than the round portion of the port on the ink repellent layer 231, and the
thickness d is preferably the maximum thickness of the ink repellent layer.
In this way, the edge of the port provided on the ink repellent layer 231,
which communicates with the port of the nozzle plate 232, is formed with a smooth
curved line having no pointed portions. This configuration makes it possible to
avoid such troubles that the ink repellent layer 231 delaminates from the nozzle plate
232 even when the injection head is wiped with a wiper formed of a material such as
rubber is caught on such pointed portions.
Further, as shown in FIG. 14B, it is preferable that a tangent line formed so
as to pass the outside edge of each of the ink ejection ports on the ink repellent layer
231 at the cross-section as a plane including the center line of one port (each of the
ink ejection ports) of the nozzle plate 232 be formed with an angle 0 less than 90

degrees with respect to the surface of the nozzle plate 232 including the outside edge
of the port of the nozzle 232, which communicates with the outside edge of the port.
By providing an angle 0 of less than 90 degrees between the tangent line at
the outside edge of the port of the ink repellent layer 231 and the surface of the
i nozzle plate 232, it is possible to stably form a meniscus (liquid surface) P at the
boundary portion between the ink repellent layer 231 and the nozzle plate 232 and to
significantly reduce the possibility of forming the meniscus P at other positions. As
a result, a meniscus-formed surface can be made stable, and thus excellent ink-
jetting stability can be obtained when an image is formed with an image forming
i apparatus using the inkjet head equipped with the nozzle plate 232.
As the silicone resin used in this embodiment, a liquid silicone resin of
room-temperature-curable type is preferable, and a liquid silicone resin associated
with hydrolysis reaction is more preferable. In the Examples to be described
hereinbelow, a silicone resin SR2411 manufactured by DOW CORNING TORAY
, SILICONE CO., LTD. was used.
Table 1 described below shows the edge shape formed from the outside
edge of one port of nozzle plate 232 to a portion near the edge of the port, and
evaluation results as to ink residue build up around the nozzle, edge delamination,
and ink-jetting stability.
(Table 1
The results shown in Table 1 demonstrated that the use of an inkjet head in
which the shape of an edge portion in an ink repellent layer 231 (near the outside
edge of a port) with the inclusion of substantially-pointed portions caused ink
residue build up around the nozzle and edge delamination after being wiped.
The use of an inkjet head having a round port edge caused no ink residue.
In comparison, the use of an inkjet head having an angle of r 15A caused partial edge delamination, and when an inkjet head having 6 > 90° as
shown in FIG. 15B was used, the jetting of ink droplets was unstable.
Further, as shown in FIG. 15C, when an inkjet head having r inkjet head having 0 > 90° was used, there may be a case where a meniscus (liquid
surface) P is formed at the boundary portion between an ink repellent layer 231 and a
nozzle plate 232, and there may be a case where a meniscus Q is formed at a
protrusion toward the center of the port in an ink repellent layer 231' (a portion at
which the cross-sectional area perpendicular to the center line of the port becomes
the smallest). For this reason, there is a possibility that the ink-jetting stability varies
when an image is recorded in an inkjet recording apparatus using an inkjet head
including the nozzle plate 232.
Next, the method of producing a nozzle member for an inkjet head *
according to the above-noted embodiment.
FIG. 16 is a view showing a structure of an inkjet head in which a silicone
resin is applied to a nozzle plate surface using a dispenser 234 according to this
embodiment to form an ink-repellency layer 231.
Specifically, on the ink ejection side surface of a nozzle 232 produced by
an Ni electrocasting, the dispenser 234 for applying a silicone solution is placed, and
by performing scanning operation with the dispenser 234 while ejecting silicone
from the tip of a needle 235 so that a nozzle plate 232 and the tip of the needle 235
i are kept at a predetermined interval, it was possible to selectively form a silicone
resin film on the ink ejection surface of the nozzle plate 232 as illustrated in FIG. 13
and FIGS. 14Ato 14C.
For the silicone resin used in this embodiment, a liquid silicone resin of
room-temperature-curable type SR2411 (viscosity: 10 mPa-s manufactured by DOW
CORNING TORAY SILICONE CO., LTD.) was ued. However, a slight amount of
silicone flow into nozzle holes and onto the back surface of the nozzle plate was
observed. The silicone resin film selectively formed in this way had a thickness of
1.2 jim and a surface roughness (Ra) of 0.18 |im.
In the coating hole of the tip of the needle 235 according to this
embodiment, a width (coating width) required for coating a target of the nozzle plate
232, is ensured, as shown in FIG. 17A. With this configuration, the entire surface of
a coating target can be completely coated by just moving a dispenser (not shown)
once in a coating direction.
In other words, the moving direction of the dispenser required for the
coating operation can be set to only one direction, and this configuration makes it
possible to cut out the need of changing the moving direction of the dispenser and of
moving it in an opposite direction.
Here, the tip of a common needle 235 is far narrower than the coating
width required for coating a nozzle plate 232, which is a coating target, and

therefore, in order to complete coating of the entire surface of the coating target,
there is a need to change the moving direction of the dispenser by 90° for coating
operation and to move the dispenser in plural directions such as in an opposite
direction. Therefore, there has been a difficulty in uniformly coating the entire
> surface of a coating target.
According to this embodiment, the width of the coating hole of the tip of
the needle 235 is ensured by only the coating width, i.e., a width required for coating
the nozzle plate 232. This configuration makes it possible to uniform the thickness
of a coating solution throughout the surface of a coating target and to obtain precise
) surface finishing.
FIG. 18 is a diagram showing coating operation using a dispenser 234
according to this embodiment. The basic configuration is similar to that shown in
FIG. 11, however, a nozzle plate surface is coated with silicone while the dispenser
jetting a gas 236 from a nozzle hole (port) of the nozzle plate 232. The gas 236 may
ibe suitably selected from various gases as long as the gas is least likely to chemically
react with the silicone used for coating. For example, it may be air. By coating a
nozzle plate surface while jetting the gas 236 from the nozzle hole(s) in this way, a
silicone resin film can be formed on only portions of the nozzle plate surface except
for the nozzle hole(s) on the nozzle plate 232.
When a similar silicone resin is made to proceed to a predetermined depth
by applying the silicone resin without jetting the gas 236 as mentioned above and
thereafter the gas 236 is jetted from the nozzle 232, an ink repellent layer composed
of the silicone resin can be formed to the predetermined depth of the nozzle wall (for
example, to the depth of several micro meters or so). That is, in addition to the ink

repellent layer 231 formed on the ink ejection surface side, a thin ink repellent layer
23 la (an ink repellent layer formed on the inner wall of a port) can be formed to the
predetermined depth from the outside edge of a port of the nozzle plate 232.
The ink repellent layer 231 formed thus on the nozzle plate is wiped using
an EPDM rubber (rubber hardness: 50 degrees). As a result, the ink repellent layer
231 could keep excellent ink repellency even when wiped 1,000 times. Further, a
nozzle member with such an ink repellent layer formed thereon was soaked in an ink
at 70°C for 14 days. Thereafter, the ink repellency on a same level as that in the
initial stage could be maintained.
FIG. 20 is a view showing one example of an inkjet head of the present
invention, and showing a state where a nozzle hole is formed by excimer laser
processing. A nozzle plate 243 is prepared by bonding a resin component 221 and a
high-stiffness component 225 with a thermoplastic adhesive 226. On a surface of the
resin component, on which the high-stiffness component 225 is not formed, an SiCh
thin layer, a thin layer 222, and a fluorine-based water-repellent layer 223 are formed
in this order. A nozzle hole 244 having a desired diameter is formed on the resin
component 221, and on the high-stiffness component 225, a nozzle-communicating
port 227 that communicates with the nozzle hole 244 is formed. The SiO2 thin layer
222 is formed by application of a relatively small amount of heat, i.e, by a method
allowing for forming a layer at a temperature within the range where the resin
component is not thermally affected. Specifically, sputtering, ion beam evaporation,
ion plating, CVD (Chemical Vapor Deposition), and P-CVD (Plasma-Chemical
Vapor Deposition) etc. are suitably employed.
It is advantageous in terms of process step time and material cost to make
the SiO2 thin layer 222 have a required minimum thickness with which the
adhesiveness can be ensured. This is because when the SiO2 thin layer 222 is thickly
formed, it will cause some trouble in nozzle hole processing with the use of an
excimer laser. Specifically, even when the resin component 221 is neatly processed
in the form of a nozzle hole, part of the SiO2 thin layer 222 cannot be satisfactorily
processed, leaving unprocessed portions. Thus, it can be said that the thickness
range of 1 angstrom to 300 angstroms (0.1 nm to 30 nm) is suitable as a thickness
range where the adhesiveness thereof can be ensured and no unprocessed portion of
the SiO2 thin layer 222 is left at the time of processing with an excimer laser. The
thickness range of 10 angstroms to 100 angstroms (1 nm to 10 nm) is more suitable.
In the experimental results, the adhesiveness between the SiO2 thin layer 222 and the
resin component 221 was satisfactory, and there was no problem with processed
results with the use of excimer laser even when the thickness of the SiO2 thin layer
was 30 angstroms (3 nm). When the thickness was set to 300 angstroms (30 nm),
unprocessed portions were slightly observed, but this was in the usable range; and
when the thickness was set to be thicker than 300 angstroms (30 nm), significantly
large unprocessed portions occurred, and nozzle deformation which was on the level
where no practical use is expected was observed.
For the material of the ink repellent layer, any materials can be used, as
long as it is a water-shedding material. Specific examples thereof include fluorine-
based water-repellent materials and silicone-based water-repellent materials.
With respect to the fluorine-based water-repellent materials, various
materials have been known. Herein, required water-repellency is obtained by

depositing a mixture (product name: OPTOOL DSX, manufactured by Daikin
Industries, Ltd) of a perfluoropolyoxetane with a modified perfluoropolyoxetane so
as to be a thickness of 1 angstrom to 30 angstroms (0.1 nm to 3 nm). In the
experimental results, even when the thickness of the OPTOOL DSX was set to 10
angstroms, 20 angstroms, and 30 angstroms, there was no difference found in the
water repellency, and wiping durability. Therefore, in view of cost, the thickness of
the ink repellent layer is more preferably 1 angstrom to 20 angstroms (0.1 nm to 2
nm). However, from the perspective of reliability, although it depends on an ink
used, the properties of the inkjet head may be maintained for a long time with the use
of a thickly formed water-repellent layer. Thus, in this case, it is preferable that the
thickness be set to 100 angstroms to 200 angstroms (10 nm to 20 nm). Further, on
the surface of the fluorine-based water repellent layer 223, an adhesive tape 224 is
affixed, the adhesive tape 224 is obtained by applying a resin film with an adhesive
material and serves as an auxiliary function at the time of processing with an
i excimer laser. A silicone-based water repellent material can be used as well.
It is preferable that the silicone-based water repellent material be a liquid
silicone resin of room temperature curable type or an elastomer; and any one of the
materials be applied onto a surface of a base, and then left in the air at room
«
temperature so as to be hardened by polymerization, thereby forming an ink repellent
i film (layer) .
The silicone-based water repellent material may also be a liquid silicone
resin of heat curable type or an elastomer; and an ink repellent film (layer) may be
formed by applying any one of the materials onto a surface of a base, and heating the
material so as to be cured.

Further, the silicone-based water repellent material may also be a liquid
silicone resin of ultraviolet curable type or an elastomer; and an ink repellent film
(layer) may be formed by applying any one of the materials onto a surface of a base,
and irradiating the material with an ultraviolet ray so as to be cured.
It is preferable that the viscosity of the silicone-based water repellent
material be 1,000 cp (centipoise) or less.
FIG. 21 is a view showing a structure of an excimer laser processor used
for processing nozzle holes. An excimer laser beam 82 emitted from a laser
oscillator 81 is reflected by mirrors 83, 85, and 88 so as to be led to a processing
table 90. In the optical path the laser beam 82 reaches the processing table 90, a
beam expander 84, a mask 86, a field lens 87, and an image forming optical system
89 are arranged at predetermined positions so that an optimum beam reaches a
process target. The process target (nozzle plate) 91 is placed on the processing table
90 and is to be exposed to the laser beam 82. The processing table 90 is an XYZ
table, which has been widely known, and is configured such that the process target
91 can be moved to a desired position if necessary so as to be exposed to a laser
beam. Here, the laser is explained with utilization of an excimer laser, however,
various types of lasers can be used, as long as it is an ultraviolet laser having a short
wavelength, which allows for abrasion processing.
FIGS. 22A to 22F are views showing production steps for producing a
nozzle plate in the production method of an inkjet head of the present invention.
FIG. 22A shows a base of a nozzle-forming component. Here, as a resin
film 221, a polyimide film, CAPTON (product name), which is free of particles,
produced by Dupont Co. is used, for example. In ordinary polyimide films, particles

such as SiC>2 (silica) are added in view of handleability (slipperiness) in apparatuses
for handling roll films. When nozzle hole processing is carried out with the use of
excimer laser, processability with excimer laser of SiO2 (silica) particles was poor,
and nozzle deformation may be caused. For this reason, in the present invention, a
i film with no addition of SiO2 (silica) particles is used. As a base material for nozzle
plate, a polyimide film, UPILEX manufactured by Ube Industries, Ltd. may be used.
Since particles contained in UPILEX are very fine and do not cause troubles in
processing, the film can be directly used.
FIG. 22B is a view showing a step of forming an SiO2 thin layer 222 on a
i surface of a resin film 221. The SiO2 thin layer 222 is suitably formed by sputtering
in a vacuum chamber, and the thickness thereof is preferably about 1 angstrom to
300 angstroms (0.1 nm to 30 nm). In this embodiment, the SiO2 thin layer 222 is
formed so as to have a thickness of 10 angstroms to 100 angstroms (1 nm to 10 nm).
In the sputtering method, firstly Si is sputtered, and then O2 ion is applied to the Si
i surface, and an SiO2 film (layer) is formed. By the use of this method, the
adhesiveness of the SiO2 layer to the resin film 221 is improved, a homogenous and
dense film can be obtained, and it is more effective in improving the wiping
durability of a water repellent layer.

FIG. 22C is a view showing a step of applying a fluorine-based water
repellant 223a onto the SiO2 thin layer. For the coating method, spin-coater, roll-
coater, screen printing, spray coater can be used, however, a film deposition by
vacuum evaporation is more effective because the adhesiveness of the water
repellent layer can be improved. By forming the SiO2 thin layer 222 in the step of
FIG. 22B, and carrying out the vacuum evaporation in the same vacuum chamber

with leaving the workpiece as it is, further favorable effect can be obtained.
Conventionally, after forming an SiO2 thin layer 222, the workpiece has been taken
out once from a vacuum chamber. Thus, it is considered that the adhesiveness is
impaired due to adhesion of impurities to the surface of the SiO2 thin layer. For the
fluorine-based water repellent material, various materials have been known,
however, in this embodiment, as a fluorine amorphous compound,
perfluoropolyoxetane, modified perfluoropolyoxetane or a mixture thereof is used.
The use of any one of these makes it possible to obtain necessary water repellency.
Note that "OPTOOL DSX" manufactured by Daikin Industries, Ltd. may be referred
to as "alkoxysilane terminal -modified perfluoropolyether".
FIG. 22D is a view showing a step of leaving the water repellency layer in
the air after evaporation thereof. In this step, the fluorine-based water repellant 223a
and the SiO2 thin layer 222 are chemically bonded each other via moisture content in
the air, thereby forming a fluorine-based water repellent layer 223.
FIG. 22E is a view showing a step of affixing an adhesive tape 224 to the
water repellency layer. At this point in time, it is necessary to affix the tape 224 so
as not to induce air bubbles. This is because a nozzle hole which is holed at a
position where air bubbles exist tends to degrade in quality due to extraneous matter
induced during processing.
FIG. 22F is a view showing a step of processing a nozzle hole 244. In this
step, an excimer laser is applied to the workpiece from the polyimide film 221 side
to thereby form the nozzle hole 244. After processing the nozzle hole 244, the
adhesive tape 224 is pealed off. Here, description on a high-stiffness component 225
used for improving the stiffness (rigidity) of the nozzle plate 243, which has been

explained in FIG. 20, is omitted. If the high-stiffness component 225 is used in these
process steps, it is advisable to form it between the step shown in FIG. 22D and the
step shown in FIG. 22E.
FIG. 23 is a view showing the outline of an apparatus used when an inkjet
head is manufactured by a method for producing an inkjet head of the present
invention.
This apparatus is manufactured according to a process method called
"Metamode process", which has been developed by OCLI (Optical Coating
Laboratory Inc.) in U.S. and has been used in production of reflection preventive
films and anti-fouling films for display. As shown in FIG. 23, at four locations
around a drum 210, an Si sputter 2O2 serving as a station, an O2 ion gun 203, an Nb
sputter 204, and an OPTOOL deposition 205 are arranged, and all of them are in a
chamber for vacuum deposition. Firstly, Si is sputtered by the Si sputter 2O2. Then,
O2 ions are applied to the Si by the use of the O2 ion gun 203 to produce SiO2.
Subsequently, Nb and OPTOOL DSX are respectively suitably deposited by the Nb
sputter 204 and the OPTOOL deposition 205. When a reflection preventive film is
produced, layers of Nb and SiO2 with a necessary number are stucked in a
predetermined thickness and then deposited. In the present invention, the function of
»
reflection preventive film is not necessary. Therefore, Nb is unnecessary, and it is
necessary only to deposit one SiO2 layer and one OPTOOL DSX layer. As described
above, by using this apparatus, it is possible to carry out vacuum evaporation of
OPTOOL DSX in the same vacuum chamber without moving the workpiece after
forming the SiO2 thin layer 122 in the vacuum chamber.
The critical surface tension of the ink repellent layer is preferably 5 mN/m
to 40 mN/m, and more preferably 5 mN/m to 30 mN/m. When the critical surface
tension is higher than 40 mN/m, an ink becomes excessively wet to the nozzle plate
in the long-time use, and thus when printing operation is repeatedly carried out, ink
ejection curve and abnormal particulation may occur, and when the critical surface
tension is higher than 40 mN/m, an ink becomes excessively wet to the nozzle plate
from the initial stage of printing operation, and therefore ink ejection curve and
abnormal particulation may occur.
Actually, each of ink repellent materials shown in Table 2 was applied onto
i an aluminum base, and the applied material was heated, dried, and thereby a nozzle
plate provided with an ink repellent layer was produced. The critical surface tension
of the ink repellent layer was measured. Table 2 shows the measurement results.
The critical surface tension can be measured by Zisman method.
Specifically, a liquid whose surface tension has been known is dropped on an ink
i repellent layer, a contact angle 6 thereof is measured, the surface tension of the
liquid is polotted along x axis, and cos 9 is plotted along y axis. As a result, a
decreasing straight line can be obtained (Zisman Plot). A surface tension obtained
when Y is equal to 1 (0 = 0) on the straight line can be calculated as a critical surface
tension yc. Besides the Zisman method, the critical surface tension can be calculated
by Fowkes method, Owens and Wendt method, or Van Oss method.
Similarly to the above-mentioned method for producing an inkjet head, an
inkjet head was produced using the the ink repellent layer-provided nozzle plate. A
cyan ink stated below was used in the inkjet head, and the ink was jetted. The ink
jetting process was videographed and observed. As a result, it was confirmed that

the ink was normally participated when any of the nozzle plates produced was used,
and there was no problem with the ejection stability. Table 2 shows the test results.

In a vessel, 20.0% by mass of copper phthalocyanine pigment-containing
polymer fine particle dispersion, 23.0% by mass of 3-methyl-l,3-butadiol, 8.0% by
mass of glycerine, 2.0% by mass of 2-ethyl-l,3-hexanediol, 2.5% by mass of FS-300
(produced by DuPont Co.) as a fluorochemical surfactant, 0.2% by mass of
PROXEL LV (produced by Avecia) as an antiseptic/antifungal agent, 0.5% by mass
of 2-amino-2-ethyl-l,3-propanediol, and an appropriate amount of ion exchange
water were added so that the total amount thereof was 100% by mass. Thereafter,
the mixture was filtered through a membrane filter having an average pore diameter
of 0.8 \ym. Through the above process, a cyan ink was produced.
Hereinafter, one aspect of performing the ink-jet recording method of
• the present invention by the ink-jet recording apparatus of the present invention will
be explained with reference to the drawings. FIG. 3 is a schematic explanatory view
showing one example of an inkjet recording apparatus of the present invention. The
ink-jet recording apparatus in FIG. 3 includes an apparatus main body 1, a paper
feed tray 2 for feeding paper that is loaded thereon into the apparatus main body 1, a
paper discharge tray 3 for storing paper which has been loaded into the apparatus
main body 1 and on which images have been recorded (formed), and an ink cartridge
loading section 6. An operation unit 7 composed of operation keys, a display and the
like is placed on the upper surface of the ink cartridge loading section 6. The ink
> cartridge loading section 6 has a front cover 8 capable of opening and closing to
attach and detach an ink cartridge 10. It should be noted that the reference numeral 5
denotes an upper cover, and the reference numeral 4 denotes the front side.
In the apparatus main body 1, as shown in FIGS. 4 and 5, a carriage 13 is
freely slidably held in the main scanning direction (indicated by the arrow A in FIG.
) 5) by a guide rod 11, which is a guide member laterally passed between left and right
side plates (not shown), and a stay 12; and the carriage 13 is moved for scanning in
the direction indicated by the arrow A in FIG. 5 by a main scanning motor (not
depicted).
A recording head 14 composed of four ink-jet recording heads which eject
i recording ink droplets of yellow (Y), cyan (C), magenta (M) and black (Bk) is
installed in the carriage 13 such that a plurality of ink ejection outlets are aligned in
the direction intersecting the main scanning direction and that the ink droplet
ejection direction faces downward.
For each of the ink-jet recording heads composing the recording head 14,
lit is possible to use, for example, a head provided with any of the following actuators
as a energy-generating unit for ejecting a recording ink: a piezoelectric actuator such
as a piezoelectric element, a thermal actuator that uses a thermoelectric conversion
element such as an exothermic resistive element and utilizes phase change caused by
film boiling of a liquid, a shape-memory-alloy actuator that utilizes metal phase

change caused by temperature change, and an electrostatic actuator that utilizes
electrostatic force.
Also, the carriage 13 incorporates sub tanks 15 of each color for supplying
the inks of each color to the recording head 14. Each sub tank 15 is supplied and
replenished with the recording ink from the ink cartridge 10 loaded into the ink
cartridge loading section 6 shown in FIG. 3, via a recording ink supply tube (not
shown).
Meanwhile, as a paper feed unit for feeding sheets of paper 22 loaded on a
paper loading section (pressure plate) 21 of the paper feed tray 2, there are provided
a half-moon roller (paper feed roller 23) which feeds the sheets of paper 22 one by
one from the paper loading section 21, and a separation pad 24 which faces the paper
feed roller 23 and is formed of a material with a large friction coefficient. This
separation pad 24 is biased toward the paper feed roller 23 side.
As a conveyance unit for conveying the paper 22, which has been fed from
this paper feed unit, under the recording head 14, there are provided a conveyance
belt 31 for conveying the paper 22 in the conveyance direction (indicated by the
arrow B in FIG. 5) by means of electrostatic adsorption; a counter roller 32 for
conveying the paper 22, which is sent from the paper feed unit via a guide 25, such
that the paper 22 is sandwiched between the counter roller 32 and the conveyance
belt 31; a conveyance guide 33 for making the paper 22, which is sent upward in the
substantially vertical direction, change its direction by approximately 90° and thusly
correspond with the conveyance belt 31; and an end pressurizing roller 35 biased
toward the conveyance belt 31 side by a pressing member 34. Also, there is
provided a charging roller 36 as a charging unit for charging the surface of the

conveyance belt 31.
The conveyance belt 31 is an endless belt and is capable of moving in
circles in the belt conveyance direction, spanned between a conveyance roller 37 and
a tension roller 38. On the back of the conveyance belt 31, a guide member 77 is
placed correspondingly to a region where printing is carried out by the recording
head 14. Additionally, as a paper discharge unit for discharging the paper 22 on
which images or the like have been recorded by the recording head 14, there are
provided a separation pawl 51 for separating the paper 22 from the conveyance belt
31, a paper discharge roller 52 and a paper discharge small roller 53, with the paper
discharge tray 3 being placed below the paper discharge roller 52.
A double-sided paper feed unit 61 is mounted on a rear surface portion of
the apparatus main body 1 in a freely detachable manner. The double-sided paper
feed unit 61 takes in the paper 22 returned by rotation of the conveyance belt 31 in
the opposite direction and reverses it, then refeeds it between the counter roller 32
and the conveyance belt 31. Additionally, a manual paper feed unit 62 is provided
on an upper surface of the double-sided paper feed unit 61.
In the ink jet recording apparatus 1, the paper 22 is separated one by one
and fed from the paper feed unit, the paper 22, which is fed upward in the
substantially vertical direction, is guided by the guide 25, and conveyed such that the
paper 22 is sandwiched between the conveyance belt 31 and the counter roller 32.
The distal end of the paper is guided by the conveyance guide 33 and pressed against
the conveyance belt 31 by end pressurizing roller 35, and the conveyance direction
thereof is changed by approximately 90°.
At this point in time, the conveyance belt 31 is charged by the charging
roller 36, and the paper 22 is conveyed by the conveyance belt 31 by means of

electrostatic adsorption. By driving the recording head 14 according to the image
signal, while moving the carriage 13, ink droplets are ejected from the recording
head 14 to record information, data or an image for one line on the paper 22 which
remains stationary, and then the paper 22 is conveyed a predetermined distance for
irecording the next line. On receipt of a recording completion signal or such a signal
as indicates that the rear end of the paper 22 has reached the recording region,
recording operation is finished, and the paper 22 is discharged onto the paper
discharge tray 3.
Once the amount of recording ink remaining in the sub tanks 15 has been
detected as too small, a required amount of recording ink is supplied from the ink
cartridge 10 into the sub tanks 15.
It should be noted that although the ink-jet recording method of the present
invention has been explained referring to an example in which it is applied to a
serial-type (shuttle-type) ink-jet recording apparatus where a carriage performs
scanning, the ink-jet recording method of the present invention can also be applied to
line-type ink-jet recording apparatuses provided with line-type heads.
The recording head 14, which is named generically a plural recording
heads) is composed, for example, as shown in FIG. 6, of a liquid droplet ejection
head 14a and a liquid droplet ejection head b. The liquid droplet ejection head 14a
has a nozzle column 14yn composed of a plurality of nozzles N that eject yellow (Y)
ink droplets and a nozzle column 14mn composed of a plurality of nozzles N that
eject magenta (M) ink droplets. The liquid droplet ejection head b has a nozzle
column 14cn composed of a plurality of nozzles N that eject cyan (C) ink droplets
and a nozzle column 14kn composed of a plurality of nozzles N that eject black (Bk)
ink droplets.
It should be noted that FIG. 6 illustrates an example that two color inks are
supplied from two different sub tanks to one recording head, i.e., four color inks of
yellow (Y), magenta (M), cyan (C), and black (Bk) are supplied from four different
sub tanks to two recording heads, thereby allowing for four-color printing. However,
the following configuration may be employed: four recording heads each having two
nozzle columns are prepared, and each different-color sub tank is allocated to each of
the four recording heads, in other words, with the use of four recording heads each
having two nozzle columns and four sub tanks, thereby allowing for four-color
printing of four color inks of yellow (Y), magenta (M), cyan (C), and black (Bk).
The example shown in FIG. 6 depicts an inkjet printer (IPSIO G505,
manufactured by Richo Company Ltd.) where nozzles ejecting different color inks
are arranged in columns on one recording head.
In an inkjet printer (IPSIO G707, manufactured by Richo Company Ltd.),
which is not illustrated in the drawings, four recording heads having the same
structure as above are provided, and each color inks of yellow ink, magenta, cyan
and black is supplied to each of the four recording heads.
It is possible to prevent a nozzle section from coming off by performing
idle scanning, in which a piezoelectric element is applied with a voltage having an
intensity by which the ink is not ejected, and to prevent nozzles from coming off by
frequently performing so-called idle ejection, in which ink droplets are ejected in an
ink reservoir. It is preferable to perform idle ejection of ink droplets once during a
time for printing at least one page.
For each of the ink-jet recording heads composing the recording head 14,
it is possible to use, for example, a head provided with any of the following actuators
as a energy-generating unit for ejecting a recording ink: a piezoelectric actuator such
as a piezoelectric element, a thermal actuator that uses a thermoelectric conversion
element such as an exothermic resistive element and utilizes phase change caused by
film boiling of a liquid, a shape-memory-alloy actuator that utilizes metal phase
change caused by temperature change, and an electrostatic actuator that utilizes
electrostatic force. It should be noted that in Examples, which will be described
hereinbelow, inkjet recording heads each using a piezoelectric actuator (a
piezoelectric element) as an energy generation unit are employed.
The carriage 13 incorporates a sub tank 15 (when the color inks are
differentiated from each other, reference numerals 15y, 15m, 15c and 15k are used so
as to correspond to each of the nozzle columns), which is a container for supplying
the inks of each color to each nozzle columns of 14yn, 14mn, 14cn and 14kn of the
recording head 14. Each of the sub tanks 15 is replenished and supplied with each of
the color inks from the main tank (ink cartridge) 10 which houses each of the color
inks (when the color inks are differentiated from each other, reference numerals lOy,
10m, 10c and 10k are used so as to correspond to each of the nozzle columns) via
ink supply tubes 16. Specifically, the main tank 10 houses the inks of each color of
yellow (Y), cyan (C), magenta (M), and black (Bk), however, the main tank 10k
accommodates a much larger amount of ink than in the main tanks lOy, 10m and 10c
which accommodate the color inks other than black color ink.
Hereinafter, the details of an ink supply device being a liquid supply
device in the above-noted recording apparatus will be explained with reference to
FIGS. 7 to 9. FIG. 7 is an exploded perspective view showing a liquid supply

device. FIG. 8 is an enlarged exploded perspective view of the liquid supply device
shown in FIG. 7. FIG. 9 is an explanatory side view showing one of the sub tanks.
The ink supply device is composed of subtanks 15 which are liquid supply
containers for supplying inks to the recording head 14 (14a, 14b) with being installed
to the carriage 13, as described above, and main tanks (ink cartridges) 10 for
supplying and replenishing the sub tanks 15 with the inks via supply tubes 16.
In one of the sub tanks 15, to a container main body (case main body) 101
forming an ink housing 100 for housing an ink, a film component having flexibility
(flexible film component) 102 for sealing an opening (one face of the subtank 15) of
the ink housing 100 is affixed with an adhesive or by welding. Further, inside of the
ink housing 100, a spring 103, which is an elastic component for biasing the film
component 102 outward, is provided between the case main body 101 and the film
component 102.
The film component 102 may have a single layer structure, however, as
shown in FIG. 10A, may have a two-layer structure where a first layer 102a and a
second layer 102b composed of different types of materials are laminated, for
example, it may have a laminate structure where film components of polyethylene
and nylon are laminated, or as shown in FIG. 10B, it may have a structure where a
»
silica deposition layer 102c is formed as the first layer 102a. With such a structure,
the liquid resistance to ink can be assuredly ensured. Also, the inclusion of a silica
deposition layer in the film component 102 makes it possible to improve the liquid
resistance to ink to be housed.
The thickness of the film component 102 is preferably 10 µm to 100 µm.
When the thickness is less than 10 µm, damage attributable to deterioration with

time is like to occur, and when the thickness is more than 100 (im, the flexibility
thereof degrades and it may be difficult to efficiently generate negative pressure.
On the film component 102, a bulge 102a being a convex along the spring
103 is formed, and a reinforcing member 104 is further affixed to the exterior surface
of the film component 102, corresponding to the bulge portion. By providing the
convex on the flexible film component 102, the elastic component (spring) 103 can
be held in a stable manner. In this case, it is possible to readily form a convex on the
flexible film component 102 by forming a convex on a sheet film component.
Further, to the case main body 101, an ink introduction path section 111 is
provided to supply ink, and a connection unit 112 for connecting the ink introduction
path section 111 to the ink supply tube 16, which is connected to the ink cartridge 10,
is detachably mounted.
Between the ink cartridge 10 and the sub tank 15, a liquid sending pump as
described below is provided so as to pressure-send the ink from the ink cartridge 10
to the sub tank 15.
Further, a connecting member 113 is attached to the downside of the case
main body 101 so as to supply the ink from the ink housing 100 to the recording
head 14. On the connecting member 113, an ink supply paths 114 are formed from
the recording head 14, and a filter 115 is provided between the connecting member
113 and the ink housing 100.
In addition, the upper part of the case main body 101, an air flow passage
121 for discharging air from the ink housing 100 is formed. The air flow passage
121 includes an inlet flow passage part 122 whose port faces the ink housing 100 and
a flow passage part 123 (referred to as "orthogonal flow passage part") led from the

the inlet flow passage part 122. The air flow passage 121 is communicated with an
air release hole 131 provided to the case main body 101 at the downstream side, and
at the place downstream the air release hole 131, in a state of use, a storage section
126 is formed in continuation of the air release hole 131.
In the air release hole 131, an air release valve mechanism 132 for
switching between a sealed state and an air released state of inside the sub tank 15 is
provided. The air release valve mechanism 132 is structured such that a valve seat
134, a ball 135 serving as a valving element and a spring 136 for biasing the ball 135
toward the valve seat 134 are housed in a holder 133.
Hereinafter, the function of the storage section 126 will be explained.
When the main body of the liquid supply device is tilted or swung, an ink is highly
likely to intrude into the air flow passage 121. Then, the storage section 126 is
structured such that the ink entered from the air flow passage 121 can be stored
therein, thereby preventing the air release valve mechanism 132 from causing
defective operation. For example, even when the liquid supply device is dropped
during transportation and ink intrudes into the air flow passage, the ink is to intrude
into the air release hole 131 and into the air release valve mechanism 132 configured
to open and close the air release hole 131 and to set therein.
»
On the top of the case main body 101, two detection electrodes 141 and
142 for detecting that the amount of ink remaining in the sub-tanks 15 has been too
small (this state is called "ink near-end") are mounted. A conduction state between
the detection electrodes 141 and 142 changes depending on a difference between a
state where both the detection electrodes 141 and 142 are soaked in an ink and a
state where at least one of them is not soaked in the ink, thereby the state of "ink
near-end" can be detected.
The inkjet recording apparatus of the present invention is, as shown in
FIGS. 11 and 12, equipped with a nozzle condition maintenance/recovery
mechanism (hereinafter, may be referred to as "sub-system") 71 which maintains and
recovers the nozzle condition of the recording head 14 and is placed in a non-
printing area, which is one side (or both sides) of the scanning direction of the
carriage 13. FIG. 11 is a top view of the condition maintenance/recovery
mechanism, and FIG. 12 is a schematic explanatory view showing one example of
units for maintaining the inkjet recording apparatus. The sub-system 71 is equipped
with capping member 72A and 72B for capping each of nozzle surfaces of recording
heads 14a and 14b, a wiper blade for wiping the nozzle surfaces. An idle ejection
receiver is provided between the capping members 72A and the wiper blade 73 at the
time when an ink is ejected. The idle ejection receiver is structured so that ink is
ejected therein and flows downstream to a waste liquid tank. Because ink is likely to
adhere to the place where ink is ejected, a wiper is provided so as to automatically
scrape off adhered ink.
Hereinbelow, the condition maintenance/recovery mechanism 71 relating
i
to the inkjet recording apparatus of the present invention will be further described in
detail.
As shown in FIGS. 11 and 12, when a motor 231 normally rotates, a pump
gear 233, an intermediate gear 234, an intermediate gear 235 and an intermediate
gear 236 are driven to rotate, and a tube pump 220 is activated to suck the inside of
the rightmost cap (on the side of recording area) which is connected with the pump

220 and a tube 219. Gears other than those mentioned above are not activated
because a one-direction clutch 237 as an operating thereof is disconnected.
When the motor 231 rotates in a reverse direction, the one-direction clutch
_237 is connected, functions connected from the motor to a cam shaft rotate,
i Although the tube pump 220 rotates in a reverse direction, it is configured so that it
is not actuated as a pump.
To a cum shaft 221, a carriage lock-cum 227, cap-cums 222B and 222A, a
wiper cum 224, a wiper cleaner cum 228 and a home position sensor cum 241 are
mounted so as to integrally rotate.
i A carriage lock 215 is biased upward (in the locking direction) by a
compression spring (not shown). The carriage lock 215 is moved up and down by a
carriage lock arm 217 that makes contact with the cum surface of the carriage lock-
cum 227.
Caps 72A and 72B and a cap holder 212A are moved up and down by the
. cap-cums 222a and 222B.
A wiper 73 is moved up and down by the wiper cum 224.
A wiper cleaner 218 is biased in a direction away from the wiper 73 by a
spring and moves in the wiping direction by the wiper cleaner cum 228. The wiper
*
73 descends down while being sandwiched by the wiper cleaner 218 and the idle
ejection receiver, thereby the ink adhering to the wiper 73 is scraped off into the idle
ejection receiver.
To the main body of the condition maintenance/recovery unit, a sensor
(photo-interruptor/not shown) is fixed, and the unit is configured such that when the
caps come to the lowest end by the home position sensor cum 241, an HP lever is

made to work, the sensor is in an open state to thereby detect the home position of a
motor (except for the motor of the pump).
When the power source is on, the caps 72A and 72B are moved up and
down irrespective of the positions of the cap holders 212Aand 212B (the positions
are not detected until the movement starts), the home positions of the caps 72A and
72B are detected (during ascending), subsequently, they move a predetermined
distance toward the lowest end. Thereafter, the carriage moves left and right to
detect the positions of the caps, then comes back to the place where the caps are
positioned, and then capped.
As the sequential order of the motor when it rotates in the reverse
direction, the caps ascend (the carriage lock ascends at a substantially same timing),
the caps descend (the carriage lock descends at a substantially same timing), the
home position sensor is opened, the wipe ascends, the wiper cleaner starts its
operation (to press the wiper against the idle ejection receiver), the wiper descends
initial position. The series of the operations are repeated.
The inkjet recording apparatus and the inkjet recording method of the
present invention can be used in various fileds of recording based on inkjet recording
method, and can be particularly suitably used, for example, in inkjet recording
i printers, facsimiles, copiers, printer/facsimile/copier complex apparatuses.
(Ink Media Set)
An ink media set of the present invention includes the recording ink of the
present invention and a recording medium and further includes other components in
accordance with the necessity.


The recording medium has a support, and a coating layer applied onto at
least one surface of the support and further has other layers in accordance with the
necessity.
In the recording medium, the amount of purified water transferred to the
recording medium for a contact period of 100 ms measured by a dynamic scanning
absorptometer is 2 mL/m2 to 35 mL/m2, and more preferably 2 mL/m2 to 10 mL/m2.
When the amount of pure water transferred to the recording medium for a
contact period of 100 ms is too small, ink beading is likely to occur, and the transfer
amount is too large, the ink dot diameter after recorded may become too smaller than
the desired dot diameter.
The amount of pure water transferred to the recording medium for a
contact period of 400 ms measured by a dynamic scanning absorptometer is 3 mL/m2
to 40 mL/m2, and more preferably 3 mL/m2 to 10 mL/m2.
When the transfer amount for a contact period of 400 ms is too small, spur
trace is likely to occur, and the transfer amount is too large, the glossiness of image
portions that have been dried is liable to degrade.
Here, the dynamic scanning absorptometer (DSA, Japan TAPPI Journal,
«
vol. 48, May 1994, pp. 88-92, Shigenori Kuga) is an apparatus which can precisely
measure the amount of liquid absorbed in a very short period of time. The dynamic
scanning absorptometer automatically conducts the measurement by a method in
which the rate of liquid absorption is directly read on the basis of the transfer of a
meniscus in a capillary, a sample is shaped like a disc, a liquid absorption head is
spirally moved for scanning on the sample, the scanning rate is automatically

changed in accordance with a preset pattern, and measurement is repeated according
to the required number of points per sample. A head for supplying liquid to a paper
sample is connected to the capillary via a Teflon (trademark) tube, and the position
of the meniscus in the capillary is automatically read by an optical sensor.
Specifically, the amount of purified water transferred was measured using a dynamic
scanning absorptometer (K350 series, type D, manufactured by Kyowaseiko
Corporation). The transfer amount for a contact period of 100ms and the transfer
amount for a contact period of 400ms can be calculated by means of interpolation
based upon the measurement values of the transfer amounts at contact periods close
to the above-mentioned contact periods.
- Support -
The support is not particularly limited and may be suitably selected in
accordance with the intended use. Examples thereof include paper made mainly
from wood fiber, and sheet-like materials such as unwoven fabrics made mainly
from wood fiber and synthetic fiber.
The paper is not particularly limited and may be suitably selected from
known materials in accordance with the intended use. For instance, wood pulp or
recycled pulp is used therefor. Examples of the wood pulp include leaf bleached
kraft pulp (LBKP), needle bleached kraft pulp (NBKP), NBSP, LBSP, GP and TMP.
Examples of the raw material for the recycled pulp include articles shown
in the "Used Paper Standard Quality Specification List" released by Paper Recycling
Promotion Center, such as high-quality white paper, white paper with lines and
marks, cream-colored paper, card, medium-quality white paper, low-quality white
paper, simili paper, white-colored paper, Kent paper, white art paper, medium-quality

colored paper, low-quality colored paper, newspaper and magazine. Specific
examples thereof include used paperboards and used papers of the following papers:
printer papers such as uncoated computer paper, thermosensitive paper and pressure-
sensitive paper that are related to information; OA (office automation) related papers
such as paper for PPC (plain paper copier); coated papers such as art paper, coated
paper, finely'coated paper and matte paper; and uncoated papers such as high-quality
paper, high color quality paper, notebook, letter paper, packing paper, fancy paper,
medium-quality paper, newspaper, woody paper, super wrapping paper, simili paper,
pure white roll paper and milk carton. More specific examples thereof include
i chemical pulp paper and high-yield pulp-containing paper. Each of these may be
used alone or in combination.
The recycled pulp is generally produced by a combination of the following
four steps.
(1) Defibration: used paper is treated with mechanical force and chemicals
i using a pulper and thusly fiberized, and printing ink is separated from the fiber.
(2) Dust removal: foreign matter (plastic, etc.) and dust contained in the used
paper is removed by a screen, a cleaner or the like.
(3) Ink removal: the printing ink that has been separated from the fiber using a
surfactant is removed from the system by a flotation method or washing method.
i(4) Bleaching: the whiteness of the fiber is enhanced utilizing oxidation or
reduction.
When the recycled pulp is mixed with other pulp, it is desirable that the
mixture ratio of the recycled pulp in the whole pulp be 40% or less so as to prevent
curl after recording.

For an internally added filler used in the support, a conventionally known
pigment as a white pigment is used, for instance. Examples of the white pigment
include white inorganic pigments such as light calcium carbonate, heavy calcium
carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc
oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous
earth, calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide,
alumina, lithopone, zeolite, magnesium carbonate and magnesium hydroxide; and
organic pigments such as styrene-based plastic pigments, acrylic plastic pigments,
polyethylene, microcapsules, urea resins and melamine resins. Each of these may be
used alone or in combination.
Examples of an internally added sizing agent used in producing the
support include neutral rosin sizing agents used in neutral papermaking, alkenyl
succinic anhydrides (ASA), alkyl ketene dimers (AKD) and petroleum resin sizing
agents. Among these, neutral rosin sizing agents and alkenyl succinic anhydrides are
particularly suitable. Although any of the alkyl ketene dimers only needs to be
added in small amounts due to its strong sizing effect, it may be unfavorable in terms
of conveyance at the time of ink-jet recording because the friction coefficient of a
recording paper (medium) surface decreases and the surface easily becomes slippery.
»
- Coating Layer -
The coating layer includes a pigment and a binder, and further includes a
surfactant and other components in accordance with the necessity.
For the pigment, an inorganic pigment or a combination of an inorganic
pigment and an organic pigment can be used.
Examples of the inorganic pigment include kaolin, talc, heavy calcium

carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white,
magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide,
magnesium hydroxide, zinc hydroxide and chlorites. Among these, kaolin is
particularly preferable in that it is superior in gloss developing property and makes it
possible to yield a texture which approximates that of paper for offset printing.
Examples of the kaolin include delaminated kaolin, calcined kaolin, and
engineered kaolin produced by surface modification or the like. In view of gloss
developing property, it is desirable that 50% by mass or more of the whole kaolin be
occupied by kaolin having a particle size distribution in which 80% by mass or more
of the particles are 2jim or less in diameter.
The amount of the kaolin added is preferably 50 parts by mass or more
based on 100 parts by mass of the binder. When the amount is less than 50 parts by
mass, sufficient effectiveness may not be obtained with respect to glossiness.
Although the maximum value of the amount is not particularly limited, it is desirable
in terms of coating suitability that the amount be 90 parts by mass or less, in view of
the kaolin's fluidity, especially thickening properties in the presence of high shearing
force.
Examples of the organic pigment include water-soluble dispersions
containing styrene-acrylic copolymer particles, styrene-butadiene copolymer
particles, polystyrene particles, polyethylene particles, etc. Each of these organic
pigments may be used in combination.
The amount of the organic pigment added is preferably 2 parts by mass to
20 parts by mass based on 100 parts by mass of the whole pigment of the coating
layer. The organic pigment is superior in gloss developing property and smaller in

specific gravity than an inorganic pigment, thereby making it possible to obtain a
coating layer which is bulky, highly glossy and excellent in surface coating property.
When the amount is less than 2 parts by mass, such effects cannot be obtained.
When it is greater than 20 parts by mass, the fluidity of a coating solution degrades,
which leads to decrease in coating operationality and which is economically
unfavorable as well.
Examples of the form of the organic pigment include dense type, hollow
type and doughnut type. However, in light of a balance among the gloss developing
property, the surface coating property, and the fluidity of the coating solution, it is
desirable that the average particle diameter be 0.2 (im to 3.0 jim, and it is further
desirable to employ a hollow type with a void ratio of 40% or more.
For the binder, an aqueous resin is preferably used.
For the aqueous resin, at least either a water-soluble resin or a water-
dispersible resin can be suitably used. The water-soluble resin is not particularly
limited and may be suitably selected in accordance with the intended use. Examples
thereof include polyvinyl alcohol and modified products of polyvinyl alcohol such as
anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol and acetal-
modified polyvinyl alcohol; polyurethane; polyvinylpyrrolidone and modified
»
products of polyvinylpyrrolidone such as copolymers of polyvinylpyrrolidone and
vinyl acetate, copolymers of vinylpyrrolidone and dimethylaminoethyl methacrylate,
copolymers of quaternized vinylpyrrolidone and dimethylaminoethyl methacrylate
and copolymers of vinylpyrrolidone and methacrylamide propyl trimethyl
ammonium chloride; celluloses such as carboxymethyl cellulose, hydroxyethyl
cellulose and hydroxypropyl cellulose; modified products of cellulose such as

cationated hydroxyethyl cellulose; synthetic resins such as polyester, polyacrylic
acid (ester), melamine resins, modified products thereof, and copolymers of
polyester and polyurethane; and poly(meth)acrylic acid, poly(meth)acrylamide,
oxidized starch, phosphoric acid-esterified starch, self-modifying starch, cationated
starch, various types of modified starch, polyethylene oxide, sodium polyacrylate
and sodium alginate. Each of these may be used alone or in combination.
Among these, polyvinyl alcohol, cation-modified polyvinyl alcohol,
acetal-modified polyvinyl alcohol, polyester, polyurethane, copolymers of polyester
and polyurethane, and the like are particularly preferable in terms of ink absorption.
The water-dispersible resin is not particularly limited and may be suitably
selected in accordance with the intended use. Examples thereof include polyvinyl
acetate, ethylene-vinyl acetate copolymers, polystyrene, styrene-(meth)acrylic acid
ester copolymers, (meth)acrylic acid ester polymers, vinyl acetate-(meth)acrylic acid
(ester) copolymers, styrene-butadiene copolymers, ethylene-propylene copolymers,
polyvinyl ethers and silicone-acrylic copolymers. Also, the water-dispersible resin
may contain a crosslinking agent such as methylolated melamine, methylolated urea,
methylolated hydroxypropylene urea or isocyanate or may be a copolymer with self-
crosslinking ability that includes N-methylolacrylamide or other unit. A plurality of
these aqueous resins can be used at the same time.
The amount of the aqueous resin added is preferably 2 parts by mass to
100 parts by mass, more preferably 3 parts by mass to 50 parts by mass, based on
100 parts by mass of the pigment. The amount of the aqueous resin added is
determined such that the liquid absorption properties of the recording medium are
within a desired range.

When a water-dispersible colorant is used as the colorant, a cationic
organic compound is not necessarily required, and a cationic organic compound is
not particularly limited and may be suitably selected in accordance with the intended
use. Examples thereof include monomers, oligomers and polymers of primary to
tertiary amines that form insoluble salts by reacting with functional groups such as
sulfonic acid group, carboxyl group and amino group in direct dye or acid dye
present in water-soluble ink; and monomers, oligomers and polymers of quaternary
ammonium salts. Among these, oligomers and polymers are preferable.
Examples of the cationic organic compound include dimethylamine-
epichlorhydrin polycondensates, dimethylamine-ammonia-epichlorhydrin
condensates, poly(trimethylaminoethyl methacrylate-methylsulfate), diallylamine
hydrochloride-acrylamide copolymers, poly(diallylamine hydrochloride-sulfur
dioxide), polyallylamine hydrochloride, poly(allylamine hydrochloride-diallylamine
hydrochloride), acrylamide-diallylamine copolymers, polyvinylamine copolymers,
dicyandiamide, dicyandiamide-ammonium chloride-urea-formaldehyde condensates,
polyalkylene polyamine-dicyandiamide ammonium salt condensates,
dimethyldiallylammonium chloride, polydiallylmethylamine hydrochloride,
poly(diallyldimethylammonium chloride), poly(diallyldimethylammonium chloride-
?
sulfur dioxide), poly(diallyldimethylammonium chloride-diallylamine hydrochloride
derivatives), acrylamide-diallyldimethylammonium chloride copolymers, acrylate-
acrylamide-diallylamine hydrochloride copolymers, polyethylenimine, ethylenimine
derivatives such as acrylamine polymers, and modified products of polyethylenimine
alkylene oxides. Each of these may be used alone or in combination.
Among these, any one of low-molecular cationic organic compounds such

as dimethylamine-epichlorhydrin polycondensates and polyallylamine hydrochloride
and any one of relatively high-molecular cationic organic compounds such as
poly(diallyldimethylammonium chloride) are preferably combined together. The
combination makes it possible to increase image density more than in the case of
independent use and further reduce feathering.
The cation equivalent of the cationic organic compound measured in
accordance with a colloid titration method (using potassium polyvinyl sulfate and
toluidine blue) is preferably 3meq/g to 8meq/g. When the cation equivalent is in this
range, a favorable result can be obtained with respect to the range of the amount of
the cationic organic compound dried and attached.
Here, in the measurement of the cation equivalent in accordance with the
colloid titration method, the cationic organic compound is diluted with distilled
water such that the solid content stands at 0.1% by mass, and pH adjustment is not
made.
The amount of the cationic organic compound dried and attached is
preferably 0.3g/m2 to 2.0g/m2. When the amount of the cationic organic compound
dried and attached is less than 0.3g/m2, such effects as sufficient increase in image
density and reduction in feathering may not be obtained.
The surfactant is not particularly limited and may be suitably selected in
accordance with the intended use, and any one of an anionic surfactant, a cationic
surfactant, an amphoteric surfactant and a nonionic surfactant can be used therefor.
Among these, a nonionic surfactant is particularly preferable. By addition of the
surfactant, the water resistance of images improves, image density increases, and
bleeding can be reduced.

Examples of the nonionic surfactant include higher alcohol ethylene oxide
adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts,
polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine
ethylene oxide adducts, fatty acid amide ethylene oxide adducts, ethylene oxide
adducts of fats, polypropylene glycol ethylene oxide adducts, fatty acid esters of
glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan,
fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, and fatty acid amides
of alkanolamines. Each of these may be used alone or in combination.
The polyhydric alcohols are not particularly limited and may be suitably
selected in accordance with the intended use. Examples thereof include glycerol,
trimethylolpropane, pentaerythrite, sorbitol and sucrose. As to the ethylene oxide
adducts, ones in which an alkylene oxide, for example propylene oxide or butylene
oxide, is substituted for part of ethylene oxide to such an extent that their water
solubility can be maintained are also effective. The substitution ratio is preferably
150% or less. The HLB (hydrophile-lipophile balance) of the nonionic surfactant is
preferably 4 to 15, more preferably 7 to 13.
The amount of the surfactant added is preferably 0 parts by mass to 10
parts by mass, more preferably 0.1 parts by mass to 1.0 part by mass, based on 100
»
parts by mass of the cationic organic compound.
Further, other components may be added to the coating layer in accordance
with the necessity, to such an extent that the object and effects of the present
invention are not impaired. Examples of the other components include additives
such as alumina powder, a pH adjuster, an antiseptic agent and an antioxidant.
The method for forming the coating layer is not particularly limited and

may be suitably selected in accordance with the intended use. For instance, a
method in which the support is impregnated or coated with a coating layer solution
can be employed. The method of impregnating or coating the support with the
coating layer solution is not particularly limited and may be suitably selected in
accordance with the intended use. For instance, the impregnation or the coating can
be carried out using a coating machine such as a conventional size press, gate roll
size press, film transfer size press, blade coater, rod coater, air knife coater, curtain
coater or the like. Among these, in view of cost, the support is preferably
impregnated or coated with the coating layer solution using a conventional size
press, gate roll size press, film transfer size press, etc. installed in a papermaking
machine, and finished using an on-machine coater.
The amount of the coating layer solution applied is not particularly limited
and may be suitably selected in accordance with the intended use. It is preferably
0.5g/m2 to 20g/m2, more preferably lg/m2 to 15g/m2, as a solid content.
If necessary, the coating layer solution may be dried after the impregnation
or the coating, in which case the drying temperature is not particularly limited and
may be suitably selected in accordance with the intended use, however, the range of
approximately 100°C to 250°C is preferable.
The recording medium may further include a back layer formed on the
back surface of the support, and other layers formed between the support and the
coating layer and between the support and the back layer. It is also possible to
provide a protective layer on the coating layer. Each of these layers may be
composed of a single layer or a plurality of layers.
Commercially available coated paper for offset printing, commercially
available coated paper for gravure printing, or the like may be used for the recording
medium, besides media for ink-jet recording, provided that its liquid absorption
properties are within the above-mentioned ranges of the present invention.
(Ink Recorded Matter)
An ink recorded matter on which an image, information or data is recorded
by means of the inkjet recording apparatus and the inkjet recording method of the
present invention is an ink recorded matter of the present invention. The ink
recorded matter has an image that has been formed on a recording medium using the
recording ink of the present invention.
The recording medium is not particularly limited and may be suitably
selected in accordance with the intended use. Examples thereof include regular
paper, coated paper for printing, glossy paper, specific paper, fabrics, films, and OHP
sheets. These may be used alone or in combination. Among these recording media,
at least any one of regular paper and coated paper for printing is preferable.
Regular papers are advantageous in their inexpensiveness. Coat papers for
printing are advantageous in that they are relatively inexpensive as compared to
glossy papers and can give a smooth and glossy image, but the drying property
thereof is poor and it has been difficult to use with a commonly used ink. However,
the drying property of coated paper has become able to improve by using the
recording ink of the present invention.
The coated papers for printing are recording media each of which has a
support and a coating layer applied onto at least one surface of the support, in which
the amount of pure water transferred to the recording medium for a contact period of

100 ms measured by a dynamic scanning absorptometer is 2 mL/m2 to 35 mL/m2,
and the amount of pure water transferred to the recording medium for a contact
period of 400 ms is 3 mL/m2 to 40 mL/m2. These transfer amounts are low as
compared to those of commercially available conventional inkjet papers. In other
words, the liquid absorbability of the coated paper for printing is lower than those of
the conventional inkjet papers.
Of these coated papers for printing, it is particularly effective to to use the
recording ink of the present invention on a recording medium which has a relatively
high liquid absorbability. Specifically, the amount of pure water transferred to the
recording medium for a contact period of 100 ms measured by a dynamic scanning
absorptometer is 7 mL/m2 to 20 mL/m2, and the amount of pure water transferred to
the recording medium for a contact period of 400 ms is 9 mL/m2 to 30 mL/m2.
When the transfer amount of a liquid for a contact period of 100 ms is
lower than the above noted range, ink beading is likely to occur, and when the
transfer amount is higher than the above noted range, the ink dot diameter after
recorded may become too smaller than the desired dot diameter. The transfer
amount of liquid for a contact period of 400 ms is lower than the above noted range,
spur trace is likely to occur due to insufficient drying property, and the glossiness of
image portions that have been dried is liable to degrade. Note that these phenomena
relates to the drying time, and the recording ink of the present invention in which the
amount of the liquid component having a high boiling point is within an appropriate
range can exhibit an effect in improving the drying property to some extent even
when recorded on paper of which the transfer amount of a liquid is lower than the
above noted range. These papers having low liquid absorbability are commercially
available as coated paper for gravure printing.
The ink recorded matters have high image quality, cause less ink bleeding,
are excellent in stability with time, and can be suitably used for various applications,
as documents with various printed letters (characters) or images recorded on their
surfaces thereof.
Examples
Hereinafter, the present invention will be further described in detail
referring to specific Examples, however, the present invention is not limited to the
disclosed Examples. On the contrary, the present invention is intended to cover
various modifications and equivalent arrangements included within the spirit and
scope of the appended claims. »
(Production Example 1)
- Preparation of Polymer Solution A -
The inside atmosphere of a 1L flask equipped with a mechanical stirrer, a
thermometer, a nitrogen gas inlet tube, a reflux tube, and a dropping funnel was
sufficiently substituted with a nitrogen gas. Thereafter, 11.2g of styrene, 2.8g of
acrylic acid, 12.0g of lauryl methacrylate, 4.0g of polyethylene glycol methacrylate,
4.0g of a styrene macromer (product name: AS-6, produced by TOAGOSEI CO.,
LTD.), 0.4g of mercapto ethanol were added to the flask, mixed and then the
temperature of the mixture was raised to 65°C.
Next, a mixed solution of 100.8g of styrene, 25.2g of acrylic acid, 108.Og
of lauryl methacrylate, 36.Og of polyethylene glycol methacrylate, 60.Og of

hydroxylethyl methacrylate, 36.Og of a styrene macromer (product name: AS-6,
produced by TOAGOSEI CO., LTD.), 3.6g of mercapto ethanol, 2.4g of azobis-
methylvaleronitrile, and 18g of methylethylketone was delivered by drops into the
flask in 2.5 hours. After the dropping, a mixed solution of 0.8g of azobis-methyl
valeronitrile and 18g of methylethylketone was delivered by drops into the flask in
0.5 hours. The mixture in the flask was aged at 65°C for 1 hour, and then 0.8g of
azobis-methyl valeronitrile was added thereto, and the mixture was further aged for 1
hour. Upon completion of the reaction, 364g of methylethylketone was added to the
flask, thereby preparing 800g of a polymer solution A with a concentration of 50%
by mass.
(Production Example 1-1)
- Production of copper phthalocyanine pigment-containing polymer fine particle
dispersion -*
Next, 46g of the thus obtained polymer solution A, 33g of a copper
phthalocyanine pigment, 13.6g of 1 mol/L potassium hydroxide, 20g of
methylethylketone, and 13.6g of ion exchange water were sufficiently stirred and
then kneaded using a roll mill to thereby obtain a paste. The obtained paste was
placed in 200g of pure water, sufficiently stirred, and then methylethylketone and
water contained therein were distilled away by the use of an evaporator. Thereafter,
glycerine was added to the reaction product, thereby producing a copper
phthalocyanine pigment-containing polymer fine particle dispersion of Production
Example 1-1 containing 10.9% by mass of pigment, 7.5% by mass of resin (solid
content 18.4% by mass) and 9.1% by mass of glycerine.
(Production Example 1-2)

- Production of aqueous dispersion of Magenta pigment
polymer fine particles -
An aqueous dispersion of magenta pigment polymer fine particles of
Production Example 1 -2 was produced in a manner similar to the process of
Production Example 1-1, except that C.I. Pigment Red 122 was used in place of the
copper phthalocyanine pigment. The aqueous dispersion of magenta pigment
polymer fine particles of Production Example 1-2 contained 13.6% by mass of
pigment, 4.5% by mass of resin (solid content: 18.1% by mass), and 9.1% by mass
of glycerine.
(Production Example 1-3)
- Production of aqueous dispersion of Yellow pigment polymer fine particles -
An aqueous dispersion of yellow pigment polymer fine particles of
Production Example 1-3 was produced in a manner similar to the process of
Production Example 1-1, except that C.I. Pigment Yellow 74 was used in place of the
copper phthalocyanine pigment. The aqueous dispersion of yellow pigment polymer
fine particles of Production Example 1-3 contained 10.9% by mass of pigment, 7.5%
by mass of resin (solid content: 18.4% by mass), and 9.1% by mass of glycerine.
(Production Example 2)
- Preparation of surface treated black pigment dispersion liquid -
Ninety grams of a carbon black having a CTAB specific surface area of
150 m2/g, a DBP oil absorption of 100 mL/lOOg was added to 3,000 mL of 2.5 N
sodium sulfate, and the components were oxidatively-treated by stirring at 60°C and
300rpm for 10 hours so as to react each other. The reaction liquid was filtered, the
filtered-out carbon black was neutralized with a sodium hydroxide solution and then

subjected to ultrafiltration. The obtained carbon black was washed with water, dried,
and then dispersed in pure water so as to contain 20% by mass of pigment (solid
content: 20% by mass), thereby producing a surface treated black pigment dispersion
liquid of Production Example 2.
(Production Example 3)
- Preparation of acrylic silicone fine particle dispersion B -
The inside atmosphere of a 1L flask equipped with a mechanical stirrer, a
thermometer, a nitrogen gas inlet tube, a reflux tube, and a dropping funnel was
sufficiently substituted with a nitrogen gas. Thereafter, 8.0g of LATEMUL S-180
(reactive emulsifier having unsaturated carbon atoms, produced by Kao
Corporation), and 350g of ion exchange water were added to the flask, mixed, and
then the temperature of the mixture was raised to 65°C. After raising the
temperature, 3.0g of t-butylperoxobenzoate serving as a reaction initiator, and l.Og
of sodium isoascorbate were added thereto, and five minutes later, 45g of methyl
methacrylate, 160g of ethylhexyl methacrylate, 5g of acrylic acid, 45g of butyl
methacrylate, 30g of cyclohexyl methacrylate, 15g of vinyltriethoxysilane, 8.0g of
LATEMUL S-180 (reactive emulsifier having unsaturated carbon atoms, produced
by Kao Corporation), and 340g of ion exchange water were mixed. Then the
mixture was delivered by drops into the flask in 3 hours. Thereafter, the mixture was
heated and aged at 80°C for 2 hours, then cooled to normal temperature, and the pH
of the reaction product was adjusted with sodium hydroxide to 7 to 8. The ethanol
contained therein was distilled away by the use of an evaporator, and the moisture
content was adjusted, thereby producing 730g of an acrylic silicone fine particle
dispersion B solution of Production Example 3, which had a solid content of 40% by

mass.
(Example 1)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 µm, thereby producing a
recording ink.

• copper phthalocyanine pigment-contianing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
*
• glycerine as a wetting agent..................11.17% by mass
• 1,3 butanediol as a wetting agent......... 13.95% by mass
• 2-ethyl-1,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)

.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 30.90% by mass. These
constituents correspond to a liquid component having a boiling point higher than that
of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to a
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 30.90/11.62, i.e. 2.66.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)

was (11.17 + 2.78)/11.62, i.e. 1.20.
Note that the resin component used herein includes the resin used from the
copper phthalocyanine pigment-containing polymer fine particle dispersion, and the
same applies to the following Examples and Comparative Examples.
(Example 2)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 ujn, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
»
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion poinf)]....... .................................15%
by mass
• glycerine as a wetting agent..................11.17% by mass
• 1,3 butanediol as a wetting agent...........9.78% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass

• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 26.73% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.30.

Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
(Example 3)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 (im, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
«
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................13.49% by mass
• 1,3 butanediol as a wetting agent...........7.46% by mass
• 2-ethyl-1,3-hexanediol as a penetrant.........2% by mass

• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 26.73% by mass. These
constituents correspond to the liquid component having a boiling point higher than*
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.30.

Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.40.
(Example 4)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 |im, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (Inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................26.27% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective

ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine which was
used as a wetting agent being liquid at normal temperature (25°C), 2-ethyl-l,3-
i hexanediol used as a penetrant being liquid at normal temperature (25°C) and the
surfactant contained was 32.05% by mass. These constituents correspond to the
liquid component having a boiling point higher than that of water and being liquid in
ink. The amount of a colorant being solid at normal temperature (25 °C)
i contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.76.
Further, a ratio (A/B) of the total amount of the water-soluble organic

solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 2.50.
(Example 5)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 (im, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................10.00% by mass
• 1,3 butanediol as a wetting agent..........10.95% by mass
• 2-ethyl-1,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective

ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 26.73% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink. ,
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-contianing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
¦*
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.30.
Further, a ratio (A/B) of the total amount of the water-soluble organic

solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.10.
(Example 6)
i - Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 |im, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
• 29.20% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................8%
by mass
• glycerine as a wetting agent.................7.62% by mass
• 1,3 butanediol as a wetting agent..........6.43% by mass
• 2-ethyl-1,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective

ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 19.71% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink. ?
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.18% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
5.39% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 8.57%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.30.
Further, a ratio (A/B) of the total amount of the water-soluble organic

solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
(Example 7)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 |im, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................11.17% by mass
• 1,3 butanediol as a wetting agent..........4.55% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective

ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 21.50% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in inki
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 1.85.
Further, a ratio (A/B) of the total amount of the water-soluble organic

solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
(Example 8)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 µm, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
¦ 30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................11.17% by mass
• 1,3 butanediol as a wetting agent..........19.07% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective

ingredient: 40% by mass)...............2.5% by mass
• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 36.O2% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 3.10.
Further, a ratio (A/B) of the total amount of the water-soluble organic

solvent having a high boiling point of 280°C or higher (A) (in this Example,
glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
(Comparative Example 1)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 fim, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........................................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (Inflexion point)].........................................15%
by mass
• glycerine as a wetting agent................29.76% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass

• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine which was
used as a wetting agent being liquid at normal temperature (25°C), 2-ethyl-1,3-
hexanediol used as a penetrant being liquid at normal temperature (25°C) and the
surfactant contained was 35.54% by mass. These constituents correspond to the
liquid component having a boiling point higher than that of water and being liquid in
ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-contianing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25 °C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.80.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,

glycerine) in the liquid component to the total amount of the solid component (B)
was 3.06.
(Comparative Example 2)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 Jim, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water]..................................................*......................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent..................4.77% by mass
• 1,3 butanediol as a wetting agent..........16.18% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass

• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
.Chemical Co., Ltd.)........................0.1%by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 26.73% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.30.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,

glycerine) in the liquid component to the total amount of the solid component (B)
was 0.65.
(Comparative Example 3)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 µm, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].....................................-....................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................15%
by mass
• glycerine as a wetting agent............... 10.00% by mass
• 1,3 butanediol as a wetting agent..........21.40% by mass
• 2-ethyl-1,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass

• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 37.18% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
it
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 3.20.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,

glycerine) in the liquid component to the total amount of the solid component (B)
was 1.10.
(Comparative Example 4)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 ujti, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].......................<..................................................> 28.00% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C (inflexion point)].........................................5%
*
by mass
• glycerine as a wetting agent............... 6.03% by mass
• 1,3 butanediol as a wetting agent..........6.43% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass

• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 18.01% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25°C)
contained in the ink composition was 3.05% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
4.10% by mass. Thus, the total amount of the colorant and the resin component
»
contained in the ink composition was 7.15%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 2.52.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,

glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
(Comparative Example 5)
- Production of Recording Ink -
An ink composition having the following formulation was prepared. After
the pH of the composition was adjusted, the composition was filtered through a
membrane filter having an average pore diameter of 5 urn, thereby producing a
recording ink.

• copper phthalocyanine pigment-containing polymer fine particle
dispersion of Production Example 1-1 [pigment: 10.9% by mass, resin: 7.5% by
mass (solid content: 18.4% by mass), glycerine: 9.1% by mass, and rest of the
content thereof: water].........\...............................................................
30.55% by mass
• acrylic silicone emulsion of Production Example 3 [solid content: 40%
by mass, rest of the content thereof: water; volume average particle diameter: 150
nm, glass transition temperature of resin component: -15°C (initial rise of
differential thermal) -6°C inflexion point)].........................................15%
by mass
• glycerine as a wetting agent............... 11.17% by mass
• 1,3 butanediol as a wetting agent..........3.39% by mass
• 2-ethyl-l,3-hexanediol as a penetrant.........2% by mass
• fluorochemical surfactant (FS-300, produced by DuPont Co., effective
ingredient: 40% by mass)...............2.5% by mass

• antiseptic/antifungal agent (PROXEL LV (produced by Avecia)
.............................................................0.05% by mass
• pH adjuster (triethanol amine)...............0.3% by mass
• silicone emulsion antifoaming agent (KM-72F, produced by Shin-Etsu
Chemical Co., Ltd.)........................0.1% by mass
• water..................rest of the amount of the composition
In the above ink composition, the total amount of glycerine and 1,3
butanediol each of which was used as a wetting agent being liquid at normal
temperature (25°C), 2-ethyl-l,3-hexanediol used as a penetrant being liquid at
normal temperature (25°C) and the surfactant contained was 20.34% by mass. These
constituents correspond to the liquid component having a boiling point higher than
that of water and being liquid in ink.
The amount of a colorant being solid at normal temperature (25 °C) ¦ contained in the ink composition was 3.33% by mass.
The total amount of the resin component composed of a resin used from
the copper phthalocyanine pigment-containing polymer fine particle dispersion and a
resin used from the acrylic silicone emulsion, contained in the ink composition was
8.29% by mass. Thus, the total amount of the colorant and the resin component
contained in the ink composition was 11.62%. These constituents correspond to the
solid component being solid in ink at 25°C. Thus, a ratio (C/B) of the total amount
of the liquid component (C) contained in the recording ink to the total amount of the
solid component (B) contained in the recording ink was 1.75.
Further, a ratio (A/B) of the total amount of the water-soluble organic
solvent having a high boiling point of 280°C or higher (A) (in this Example,

glycerine) in the liquid component to the total amount of the solid component (B)
was 1.20.
Next, the surface tension, pH and viscosity of the recording inks obtained
in each of Examples 1 to 8 and Comparative Examples 1 to 5 were measured as
described below. Table 3 shows the measurement results.

The pH of each of the recording inks was measured at 23°C by means of a
pH meter (Model HM3A, manufactured by Toa Denpa Kogyo K.K.).

The viscosity of each of the recording inks was measured using a
viscometer (Model RE500, manufactured by TOKI SANGYO CO., LTD.) using a
cone 34xR24, at 180 rpm, at the timing of 3 minutes later of the start of the
measurement, at a temperature of 25°C.

The surface tension of each of the recording inks is a static surface tension
measured by a surface tension measuring device (CBVP-Z, manufactured by Kyowa
Interface Science Co., Ltd.), with the use of a platinum plate at a temperature of
Next, an inkjet printing test was carried out according to the following
manner using each of the recording inks of Examples 1 to 8 and Comparative
Examples 1 to 5.
i
Each of the recording inks obtained was jet-printed using an inkjet printer
(GX5000, manufactured by Ricoh Company Ltd.). On a nozzle plate surface of the
inkjet printer, a silicone resin film (room temperature-curable silicone resin, SR2411,
produced by DOW CORNING TORAY SILICONE CO., LTD.) was provided, the
i thickness of the resin film was 1.2 |im, the surface roughness (Ra) was 0.18 (im, and
the critical surface tenstion was 21.6 mN/m. The inkjet printing was carried out at a
temperature of 23°C, a relative humidity of 50%, with the use of high-grade regular
paper/fine mode. The drive waveform of an inkjet head was adjusted so that the
amount of each ink ejected became constant.
As a recording medium, the after-mentioned coated paper for gravure
printing was used. The amount of pure water transferred to the paper for gravure
printing (to the recording medium) measured by a dynamic scanning absorptometer
for a contact time of 100 ms was 8.5 mL/m2, and the amount of pure water
transferred to the recording medium measured by a dynamic scanning absorptometer

for a contact time of 400 ms was 14.8 mL/m2. The transfer amount of pure water
was measured at 23°C and 50%RH.

Hydroxyether derived from potato starch (SOLVICOTE 100, produced by
Avebe Inc.) was gelatinized to prepare a starch solution with a concentration of 13%,
and a no-sized, acid-free pressed paper having a basis weight of 76g/m2 and an ash
content of 13% was coated with the starch solution of 60°C on both sides thereof
using a transfer-type roll coater so that the amount of the solid content adhered was
0.3g/m2. This size-pressed paper was dried, followed by a super-calender treatment
in which the front surface and back surface of the size-pressed paper were coated
with a coating solution by means of a blade coater to form a coat layer so that the
dried solid content for each of the coat layers was 12g/m2. The coating solution was
prepared-so that 2 parts of starch (MS-4600, produced by Nihon Shokuhin Kako Co.,
Ltd.) and 7 parts of a latex (L-1457, produced by Asahi Kasei Corporation) with 100
parts of a pigment.
Subsequently, beading, image drying property, ejection stability in inkjet
printing test, and inkjet printing test results after long-time stoppage of printing
operation of each of obtained image prints were evaluated in accordance with the
following manner. Table 4 shows the evaluation results.

The presence or absence of beading in a cyan or green-color solid image
portion was visually observed and evaluated based on the following criteria.
[Evaluation criteria]
A: No beading occurred, and thus a uniform print was obtained.

B: A slight tendency of beading was observed.
C: The occurrence of beading was clearly observed.
D: The occurrence of beading in a considerable amount of beading was
observed.
E: The occurrence of beading in a substantial amount was observed.

A cyan-color solid image of 12 cm square was printed, and 10 seconds
later, a filter paper was applied to the solid image portion, and the amount of the
cyan ink transferred to the filter paper was evaluated based on the following levels of
the drying property.
[Level of Drying Property]
Level 1 .....A large amount of the ink was transferred to a filter paper.
Level 2.....A relatively large amount of the ink was transferred to a filter
paper.
Level 3......A small amount of the ink was transferred to a filter paper.
Level 4.....A slightly amount of the ink was transferred to a filter paper
when observed closely.
Level 5......The ink was not transferred at all to a filter paper.
test (evaluation of short-term reliability) >
Under the environment of a temperature of 25°C and a relative humidity of
20%, each of the recording inks of Examples and Comparative Examples was set at
an inkjet printer (GX5000, manufactured by Ricoh Company Ltd.) and then the
intermittent ejection stability of each of the inks was evaluated. Firstly, a nozzle

check pattern was recorded, and it was confirmed that no nozzle clogging was
caused. Then, an idle scanning operation of the carriage was executed without
ejecting the ink for 30 seconds. After that, the ink was dropped and printed on an
inkjet matte coated paper while jetting 20 droplets of the ink from each of all
nozzles, and then a recovery operation was carried out (purged 50 droplets). A series
of the above operations was repeated 10 times, thereby evaluating the ejection
stability of each of the recording inks. Enlarged photographs of dots formed by 20
droplets, in particular, a dot formed by a first droplet dropped, were taken during
printing. The obtained photographs were visually observed, and the jetting state
(presence or absence of ejected ink, inkjet direction) was evaluated based on the
following criteria.
[Criteria for judgment in evaluation of inkjet direction of dot formed by first droplet]
A.....There was no change in the orbit of the ejected ink and nozzles were
arranged in a row.
B.....The orbit of the ejected ink slightly changed, and a dot formed by a
first droplet did not overlap a dot formed by a secondarily dropped droplet.
C......A dot formed by a first droplet crossed the line of a dot formed by
a secondarily dropped droplet.
D......No ejected ink was found.
i nozzle clogging) >
Under the environment of a temperature of 25°C and a relative humidity of
20%, each of the recording inks of Examples and Comparative Examples was set at
an inkjet printer (GX5000, manufactured by Ricoh Company Ltd.) and it was

confirmed that no nozzle clogging was caused. Thereafter, the inkjet recording head
was uncapped by pulling down a cap unit (in a state where nozzles were likely to
dry, acceleration test), and then the nozzles were left intact for 24 hours. Thereafter,
a nozzle check pattern was recorded, and the extent of nozzle clogging was
determined and evaluated based on the following criteria.
[Evaluation Criteria]
A: There was no nozzle clogging (non-ejection of ink) observed.
B: Nozzle clogging was observed in one nozzle to less than 10 nozzles.
C: Nozzle clogging was observed in ten nozzles to less than 30 nozzles.
D: Nozzle clogging was observed in 30 nozzles to less than 100 nozzles.
E: Nozzle clogging was observed in 100 or more nozzles.
When the recording ink of Comparative Example 4 was used, abrasion and
cockling were observed on the filter paper surface.
The results shown in Table 4 demonstrate that the use of each of the
recording inks of Examples 1 to 8 made it possible to obtain printed images hardly
causing color stain (ink stain) even when grazed within one minute after being
printed, without substantially causing problems with drying time, and also made it
possible to obtain printed images having image shrpness and quality close to those of
printed matters.
Industrial Applicability
A recording ink of the present invention allows for obtaining a high quality
image that is close in quality to recorded matters produced by commercial printing
and printed matters, without substantially causing problems with drying time.
Therefore, the recording ink can be suitably used in ink media sets, ink cartridges,
ink recorded matters, inkjet recording apparatuses, and inkjet recording methods.
An inkjet recording apparatus and an inkjet recording method of the
present invention can be used in various fields of recording based on inkjet recording
method, and can be particularly suitably used, for example, in inkjet recording
printers, facsimiles, copiers, printer/facsimile/copier complex apparatuses.
CLAIMS
1. A recording ink comprising:
a solid component containing a colorant and a resin, and being solid in ink
at 25°C,
a liquid component having a boiling point higher than that of water and
being liquid in ink at 25 °C, and
water,
wherein the total amount of the solid component contained in the
recording ink is equal to 8.5% by mass or higher and less than 15% by mass, a ratio
(A/B) of the total amount of a water-soluble organic solvent (A), which is contained
in the liquid component and has a high-boiling point of 280°C or higher (A), to the
total amount of the solid component (B) contained in the recording ink is 1.1 to 2.5,
and a ratio (C/B) of the total amount of the liquid component (C) in the recording ink
to the total amount of the solid component (B) in the recording ink is 1.85 to 3.10.
2. The recording ink according to claim 1, wherein the liquid component
comprises a wetting agent, and the wetting agent is at least one selected from
glycerine, 1,3-butanediol, 3-methyl-l,3-butanediol, 2-pyrrolidone, and N-methyl-2-
pyrrolidone.
3. The recording ink according to any one of claims 1 and 2, wherein the
liquid component comprises a penetrant, and the penetrant is a polyol compound
having 8 to 11 carbon atoms.

4. The recording ink according to any one of claims 1 to 3, wherein the liquid
component comprises a surfactant, and the surfactant comprises a fluorochemical
surfactant.
5. The recording ink according to any one of claims 1 to 4, wherein the resin
comprises resin fine particles.
6. The recording ink according to claim 5, wherein the resin fine particles
comprise an acrylic silicone resin, and the acrylic silicone resin has a glass transition
temperature of 25°C or lower.
7. The recording ink according to any one of claims 5 to 6, wherein the resin
fine particles have a volume average particle diameter of 10 nm to 1,000 nm in a
resin emulsion.
8. The recording ink according to any one of claims 1 to 7, wherein the
colorant is a polymer emulsion pigment in which a water-insoluble or substantially
water-insoluble coloring material is contained in polymer fine particles.
9. The recording ink according to any one of claims 1 to 8, wherein the colorant is a
pigment which has an anionic hydrophilic group on its surface.
10. The recording ink according to any one of claims 1 to 9, having a surface
tension of 35mN/m or lower at 25°C.
11. An ink media set comprising:
the recording ink according to any one of claims 1 to 10, and
a recording medium having a support and a coating layer applied onto at
least one surface of the support,
wherein the amount of pure water transferred to the recording medium for
a contact period of 100 ms measured by a dynamic scanning absorptometer is 2 mL/
m2 to 35 mL/m2, and the amount of pure water transferred to the recording medium
for a contact period of 400 ms is 3 mL/m2 to 40 mL/m2.
12. An ink cartridge comprising:
a container to accommodate the recording ink according to any one of
claims 1 to 10.


A recording ink containing: a solid component containing a colorant, and a resin, and being solid in ink at 25 C, a
liquid component having a boiling point higher than that of water and being liquid in ink at 25 C, and water, wherein the total amount
of the solid component contained in the recording ink is equal to 8.5% by mass or higher and less than 15% by mass, a ratio (A/B)
of the total amount of a water-soluble organic solvent (A), which is contained in the liquid component and has a high-boiling point
of 280 C or higher (A), to the total amount of the solid component (B) contained in the recording ink is 1.1 to 2.5, and a ratio (C/B)
of the total amount of the liquid component (C) in the recording ink to the total amount of the solid component (B) in the recording
ink is 1.85 to 3.10.

Documents:

357-KOLNP-2010-(08-10-2014)-CLAIMS.pdf

357-KOLNP-2010-(08-10-2014)-CORRESPONDENCE.pdf

357-KOLNP-2010-(08-10-2014)-FORM-13.pdf

357-KOLNP-2010-(08-10-2014)-PA.pdf

357-KOLNP-2010-(13-11-2014)-CORRESPONDENCE.pdf

357-KOLNP-2010-(13-11-2014)-OTHERS.pdf

357-KOLNP-2010-(13-12-2013)-CORRESPONDENCE.pdf

357-KOLNP-2010-(13-12-2013)-FORM-3.pdf

357-KOLNP-2010-(19-03-2013)-CORRESPONDENCE.pdf

357-KOLNP-2010-(19-03-2013)-FORM 3.pdf

357-KOLNP-2010-(22-11-2013)-ABSTRACT.pdf

357-KOLNP-2010-(22-11-2013)-ANNEXURE TO FORM 3.pdf

357-KOLNP-2010-(22-11-2013)-CLAIMS.pdf

357-KOLNP-2010-(22-11-2013)-CORRESPONDENCE.pdf

357-KOLNP-2010-(22-11-2013)-DESCRIPTION (COMPLETE).pdf

357-KOLNP-2010-(22-11-2013)-DRAWINGS.pdf

357-KOLNP-2010-(22-11-2013)-FORM-2.pdf

357-KOLNP-2010-(22-11-2013)-OTHERS.pdf

357-KOLNP-2010-(22-11-2013)-PETITION UNDER RULE 137.pdf

357-KOLNP-2010-(24-06-2014)-CORRESPONDENCE.pdf

357-KOLNP-2010-(24-06-2014)-FORM-1.pdf

357-KOLNP-2010-(24-06-2014)-FORM-2.pdf

357-kolnp-2010-abstract.pdf

357-KOLNP-2010-ASSIGNMENT.pdf

357-kolnp-2010-claims.pdf

357-KOLNP-2010-CORRESPONDENCE.1.1.pdf

357-kolnp-2010-correspondence.pdf

357-kolnp-2010-description (complete).pdf

357-kolnp-2010-drawings.pdf

357-kolnp-2010-form 1.pdf

357-KOLNP-2010-FORM 18.pdf

357-kolnp-2010-form 2.pdf

357-KOLNP-2010-FORM 3.1.1.pdf

357-kolnp-2010-form 3.pdf

357-kolnp-2010-form 5.pdf

357-kolnp-2010-gpa.pdf

357-kolnp-2010-international publication.pdf

357-kolnp-2010-pct priority document notification.pdf

357-kolnp-2010-pct request form.pdf

357-kolnp-2010-specification.pdf

abstract-357-kolnp-2010.jpg


Patent Number 263988
Indian Patent Application Number 357/KOLNP/2010
PG Journal Number 49/2014
Publication Date 05-Dec-2014
Grant Date 28-Nov-2014
Date of Filing 29-Jan-2010
Name of Patentee RICOH COMPANY, LTD.
Applicant Address 3-6, NAKAMAGOME 1-CHOME, OHTA-KU, TOKYO, 1438555, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 MOROHOSHI, NAOYA 319-514, ASHITAKA, NUMAZU-SHI, SHIZUOKA, 4100001, JAPAN
2 NAMBA, MICHIHIKO 770-63, YABE-CHO, TOTSUKA-KU, YOKOHAMA-SHI, KANAGAWA, 2440002, JAPAN
PCT International Classification Number B41J2/01; B41M5/00; B41M5/50
PCT International Application Number PCT/JP2008/066926
PCT International Filing date 2008-09-12
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2007-238669 2007-09-14 Japan