Title of Invention

INK-JET RECORDING INK, INK-JET RECORDING INK SET, INK-JET RECORDING INK MEDIA SET,INK CARTRIDGE , INK-JET RECORDING METHOD AND INK-JET RECORDING APPARATUS

Abstract An ink-jet recording ink including water, a water-soluble organic solvent, a pigment as a colorant (B), and at least one fluorochemical surfactant selected from compounds represented by Structural Formula (1) below, Structural Formula (1) where R1 denotes any one of a hydrogen atom, an alkyl group and a perfluoroalkyl group, R2 denotes any one of a hydrogen atom, an alkyl group and a fluorine-containing group, Rf denotes a fluorine-containing group, and m and n each denote an integer of 1 or greater.
Full Text

DESCRIPTION
INK-JET RECORDING INK, INK-JET RECORDING INK SET,
INK-JET RECORDING INK MEDIA SET, INK CARTRIDGE,
INK-JET RECORDING METHOD AND INK-JET RECORDING
APPARATUS
Technical Field
The present invention relates to an ink-jet recording ink,
an ink-jet recording ink set, an ink-jet recording ink media set,
an ink cartridge, an ink-jet recording method and an ink-jet
recording apparatus which are superior in increasing image
density, improving color development and reducing color bleeding
on plain paper, and which are capable of recording high-quality
images that are comparable with those produced by commercial
printing such as offset printing, when the ink-jet recording ink of
the present invention is combined with a specific recording
medium.
Background Art
Ink-jet recording is known as a superior recording method
that is not much affected by the types of recorded materials.
Recording apparatuses, recording methods, recording materials
and the like based upon ink-jet recording have been actively
studied and developed. Hitherto, inks containing aqueous dyes


composed mainly of water have been most commonly used for
ink-jet recording inks. The inks are still most commonly used in
present-day ink-jet recording because they have many such
advantages as follows coloring materials high in absorption
coefficient and also high in color purity can be easily obtained to
prepare them, the inks can be easily made multicolored so as to
widen color exhibiting ranges, the inks' long-term storage
stability and the inks' stability against heat can be secured, and
most notably inks capable of reducing the occurrence of kogation
can he produced.
However, since the dye inks are disadvantageous in terms
of weatherability and water resistance, studies on pigment inks
that contain pigments instead of aqueous dyes have been
remarkable in recent years, and pigment inks are put on the
market these days. Unfortunately though, pigment inks still
remain more problematic than dye inks in color-developing
ability and stability;, and along with the improvements in
techniques for increasing image quality, particularly in relation
to printers for office automation, pigment inks have been
required to exhibit printing quality, hues, color saturation,
glossiness, storage stability and the like on plain paper that are
comparable with those exhibited by dye inks.
Additionally, in general, magenta inks and cyan inks used
particularly as pigment inks contain C. I. Pigment Red 122 and C.


I. Pigment Blue lo-"3 respectively, and thus pigment inks have
color reproducing ranges that are different from those of dye inks.
Also, in order to reduce hue errors, toning is often carried out, in
which case the color saturation inevitably decreases, thereby
causing a problem with printing quality.
Meanwhile, in order to change hues without depending
upon toning, pigments themselves are improved as well. For
instance, Patent Literature 1 proposes a cyan pigment having a
hue in the same color gamut as that of a cyan dye, by employing a
phthalocyanine pigment with a specific crystal structure!
however, not all requirements are satisfied, as there are problems
concerning costs, etc.
There are many other proposals including the proposal of
Patent Literature 2, which discloses an ink set wherein a pigment
is used for a coloring material for a black ink, whereas dyes are
used for coloring materials for yellow, magenta and cyan inks.
However, pigment-containing inks which have satisfactory
printing properties on plain paper have not yet been obtained in
reality.
Additionally, as an ink set including a black ink and color
inks, Patent Literature 3 discloses an ink set including a black
ink that contains a self-dispersible carbon black as a coloring
material, and color inks that contain coloring materials, wherein
the coloring material for the black ink and the coloring materials


for the color inks have opposite polarities. Further, patent
Literature 4 discloses an ink set including inks in which
colorant-containing resins are dispersed, wherein the inks have
different ionicities. However, as to printed matter produced
using these ink sets, although bleeding on boundaries between
colors can be reduced, other printing properties on plain paper
still remain unsatisfactory.
Meanwhile, as a low surface-tension aqueous pigment ink
with stable ejection properties and improved wettability, for
instance, Patent Literature 5 proposes an ink-jet printing ink
containing a water-soluble organic solvent, a colorant, water and
a perfluoroalkyl sulfonate. Additionally, as described in Patent
Literature 6 to Patent Literature 8, there are some proposals of
ink compositions for which fluorochemical surfactants are used.
However, all these proposals present such a problem that in the
case where pigments are used for colorants, the colorants are
inferior in dispersion stability, fixation on recording media and
color-developing ability. Also, in general, low surface-tension
aqueous inks with improved wettability (including the inks of
Patent Literature 5 to Patent Literature 8) present such a
drawback that fluorochemical surfactants used in the inks cause
the inks to foam greatly, and thus there are very serious effects
on the ink feeding capability and the ejection stability of nozzles.
As for media, conventional ink-jet paper, particularly


ink-jet glossy media, can be classified into swellable media and
void-type media; these days, void-type media, which are superior
in ink drying rate, are more popular. As these void-type media,
media each incorporating an ink-absorbing layer that has voids
through which ink is to be supplied onto a substrate, and also
incorporating, if necessary, a porous glossy layer are most
commonly used. As disclosed in Patent Literature 9 and Patent
Literature 10, each of such void-type media can be obtained as
follows-* a coating solution in which silica or an alumina hydrate
is dispersed is applied onto a substrate in one or more layers; and,
if necessary, a glossy layer containing a large amount of colloidal
silica is applied over the layer(s). Paper of this type is designed,
with importance being placed on its compatibility with dye inks
that are most commonly used at present, and the paper is already
widely used as ink-jet paper, particularly as glossy paper. Use
of the paper makes it possible to obtain very high definition
output with high glossiness; on the other hand, since materials
for the paper are very expensive and processes of producing the
paper are complicated, the production costs of the paper are far
higher than those of ordinary glossy coated paper for commercial
printing. Thus, the use of the paper tends to be limited to cases
where high-definition output such as photographic output is
needed; and in reality the paper is difficult to use in the field of
commercial printing where a great deal of output is required at


low costs, for example in the production of handbills, catalogues,
pamphlets, etc. These days, for the sake of higher image quality,
the number of colors of inks used in printing tends to be increased,
and the required ink absorbability tends to be increased as well.
To increase the ink absorbability of media, it is reasonable to
increase the thickness of ink receiving layers (coat layers);
however, the thicker they are, the more expensive the materials
therefor are, which leads to a rise in the unit prices of the media.
For pigments that form the ink-absorbing layers (receiving
layers), it is necessary to use materials which are small in
refractive index and have low concealing properties, in other
words which are capable of keeping the transparency of the layers
high and which absorb large amounts of oil (have large specific
surface areas). Thus, in reality, there is no choice but to use
large amounts of expensive low refractive-index, high
oil-absorbing pigments such as silica or alumina hydrates, as
opposed to inexpensive white pigments such as calcium carbonate
and kaolin. Specifically, this is because if pigments having low
transparency and high concealing properties are used for the
ink-absorbing layers, coloring materials in inks that have soaked
into the ink-absorbing layers are concealed by these pigments
having high concealing properties, thereby causing a reduction in
density. In fact, when paper which contains a pigment having
high concealing properties is subjected to ink-jet printing with a


dye ink, density is derived only from a coloring material present
in the vicinity of a surface layer of the paper, no matter now
increased the amount of ink to be applied is; thus, the density is
low as a whole, and an image with little contrast is produced.
Meanwhile, when a material which absorbs only a small amount
of oil is used, ink absorption is insufficient, and thus beading
easily arises.
Accordingly, these days, attempts to achieve a favorable
balance between the refractive index and the whiteness are made
by using fine organic particles having a small refractive index, as
disclosed in Patent Literature 11; however, the fine organic
particles, too, are high in production cost, and so it is still
difficult to obtain inexpensive ink receiving paper which is
compatible with dye inks.
As for the design concept for long-term storage stability of
images produced, since dye molecules themselves are not highly
resistant to ultraviolet rays or ozone, such a method is most
commonly employed that a dye is made to soak into an ink
receiving layer of a medium as deeply as possible so as to
minimize the effects of the air and ultraviolet rays, and the dye is
protected with an antioxidant or stabilizer previously added into
an image receiving layer of the medium. Accordingly, by using a
large amount of ink in which the concentration of a coloring
material is relatively low, deep penetration of the ink is secured


(ensured) and Image storage stability is maintained.
Consequently, the amount of ink necessary to output images
thereby increases, which not only makes it difficult to
miniaturize cartridges but also raises printing costs.
Judging from the above-mentioned points, in ink-jet
recording, it is very difficult to provide inexpensive ink-jet paper
and a printing method which are capable of high-definition
output.
Meanwhile, in recent years, note has been taken of
pigment inks for ink-jet recording. Since pigments are insoluble
in water, pigment inks in which pigments are formed as fine
particles and dispersed in solvents are generally used. As
pigment inks for ink-jet recording, however, pigment inks in
which pigments are dispersed in water are most commonly used
in view of safety, etc. Generally, aqueous pigment inks easily
cause flocculation or precipitation of pigment particles in
comparison with dye inks; in order for the long-term, storage
stability of the aqueous pigment inks to be comparable with that
of dye inks, various dispersion conditions and additives are
necessary; also, dispersion stabilizers cause kogation; thus, the
aqueous pigment inks are difficult to use with thermal heads, and
also there is such a drawback that many of them contain coloring
materials which are narrower in color exhibiting range than dyes.
Nevertheless, the aqueous pigment inks have been attracting


more and more attention for their printing quality, such as their
capability of obtaining high black density, and for their storage
stability and water resistance after recording. Ink-jet printers
using the pigment inks are deemed able to approximate the
texture of printed matter to that of printed matter produced by
commercial printing because the coloring materials contained in
the pigment inks are similar to those contained in ordinary
commercial printing inks; however, when coated paper for
commercial printing is actually printed with images or the like
using conventional pigment inks, the pigment inks do not dry as
quickly as they should, and thus the images or the like bleed, or
pigments are not fixed at all after dried, for example;
consequently, as in related art, the ink-jet printers are only
suitable for printing onto media which have high ink-absorbing
properties, such as plain paper and ink-jet paper. This is
because the design concept concerning the formation of ink-jet
images is no different from the concept in the case where dye inks
are used; specifically, the pigments as coloring materials are
merely viewed as dyes having high light resistance, and
characteristics of the pigment inks are not considered at all.
Patent Literature 12 and Patent Literature 13 each
disclose an image recording method employing an ink-jet
recording method in which pigment inks are applied onto
inexpensive general-purpose paper for commercial printing, not


ink-jet paper. However, the image recording method presents
the following problems; the inks are attached in large amounts to
the inexpensive general-purpose paper for commercial printing,
which necessitates spending a great deal of time in drying the
inks; moreover, in this state where the inks are excessively-
attached to the printing paper surface, the inks having different
colors become adjacent to one another before being absorbed into
the printing paper, and thus bleeding between the different colors
easily arises.
Patent Literature 14 discloses a method in which in order
to produce a color proof using an ink-jet printer, a precoating
solution having a function of flocculating a pigment is attached
onto a recording medium before printing is performed by the
ink-jet printer. However, this method is problematic in that the
process of attaching the precoating solution makes operation
complicated, and also in that when the precoating solution is
attached onto the recording medium, the amount of water
attached per unit area of the recording medium is large, which
easily causes troubles in conveying the recording medium, such
as curling and cockling.
[Patent Literature l] Japanese Patent Application
Laid-Open (JP-A) No. 2000-17207
[Patent Literature 2] JP-A No. 2000-239590
[Patent Literature 3] JP-A No. 10-140064


[Patent Literature 4] JP-A No. 2000-191972
[Patent Literature 5] JP-A No. 57-90070
[Patent Literature 6] JP-A No. 04-211478
[Patent Literature 7] JP-A No. 05-263029
[Patent Literature 8] JP-A No. 06-200200
[Patent Literature 9] JP-A No. 2005-212327
[Patent Literature 10] JP-A No. 11-078225
[Patent Literature 11] JP-A No. 2003-025717
[Patent Literature 12] JP-A No. 2002-67473
[Patent Literature 13] JP-A No. 2002-69346
[Patent Literature 14] JPA No. 2003-211819.
Disclosure of Invention
In light of the above-mentioned practical situations, the
present invention is designed to achieve the following aim.
Specifically, an object of the present invention is to provide
an ink-jet recording ink, an ink-jet recording ink set, an ink-jet
recording ink media set, an ink cartridge, an ink-jet recording
method and an ink-jet recording apparatus, wherein a
combination of a fluorochemical surfactant having a specific
structure and a pigment serving as a colorant on plain paper
makes it possible to increase image density, improve color
development and reduce color bleeding on the plain paper; a
combination of the ink-jet pigment ink and an ink-jet recording


medium shown in the present invention makes it possible to
obtain printed matter which is inexpensive, excellent in quality,
superior in density, glossiness and image reliability and
comparable with commercial printed matter; and it is possible to
secure superior reliability in terms of ejection stability, storage
stability and the like.
The above-mentioned aim can be achieved by the present
invention explained below.
(1) An ink-jet recording ink including water, a water-soluble
organic solvent, a pigment as a colorant (B), and at least one
fluorochemical surfactant selected from compounds represented
by Structural Formula (l) below,

Structural Formula (1)
where R1 denotes any one of a hydrogen atom, an alkyl
group and a perfluoroalkyl group, R2 denotes any one of a
hydrogen atom, an alkyl group and a fluorine-containing group,
Rf denotes a fluorine-containing group, and m and n each denote

an integer of 1 or greater.
(2) The ink-jet recording ink according to (1), further
including a water-dispersible resin (A), wherein the
water-soluble organic solvent is at least one selected from the
group consisting of glycerin, trimethylolpropane, ethylene glycol,
diethylene glycol, triethylene glycol, propylene glycol,
dipropylene glycol, tripropylene glycol, 1,3_butanediol,
2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol,
1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-hexanediol,
2-pyrrolidone, N-methyl-2-pyrrolidone,
N-hydroxyethyl-2-pyrrolidone, tetramethylurea and urea.
(3) The ink-jet recording ink according to (2), wherein the
water-dispersible resin (A) contains at least one resin emulsion
selected from the group consisting of an anionic self-emulsifiable
ether-based polyurethane resin emulsion and an acrylic-silicone
resin emulsion.
(4) An ink-jet recording ink including water, a water-soluble
organic solvent, a water-dispersible resin (A), a pigment as a
colorant (B), and at least one fluorochemical surfactant selected
from compounds represented by Structural Formula (1) below,
wherein the ink-jet recording ink has a surface tension of
20mN/m to 35mN/m at 25°C and a viscosity of 5mPas or greater
at 25°C, wherein the total amount of the water-dispersible resin
(A) and the colorant (B) present in the ink-jet recording ink is 5%


by mass to 40% by mass, and a mass ratio (A)/(B) of the
water-dispersible resin (A) to the colorant (B) is in the range of
0.5 to 4, and wherein the ink-jet recording ink is suitable for
ink-jet recording on an ink-jet recording medium for pigment ink,
which includes a support containing cellulose pulp, and one or
more barrier layers on one or both surfaces of the support, with
the one or more barrier layers containing 30% by mass or more of
an inorganic pigment that is different from an alumina hydrate
and that has a refractive index of 1.5 or greater, and containing
10% by mass or less of a pigment that has a refractive index of
less than 1.5,

Structural Formula (1)
where R1 denotes any one of a hydrogen atom, an alkyl
group and a perfluoroalkyl group, R2 denotes any one of a
hydrogen atom, an alkyl group and a fluorine-containing group,
Rf denotes a fluorine-containing group, and m and n each denote .
an integer of 1 or greater.
(5) An ink-jet recording ink media set including the ink-jet

recording' ink according to any one of (2) to (4), and an ink-jet
recording medium for pigment ink, which includes a support
containing cellulose pulp, and one or more barrier layers on one
or both surfaces of the support, with the one or more barrier
layers containing 30% by mass or more of an inorganic pigment
that is different from an alumina hydrate and that has a
refractive index of 1.5 or greater, and containing 10% by mass or
less of a pigment that has a refractive index of less than 1.5.
(6) An ink-jet recording ink set including a black ink, and
color inks, wherein each of the black ink and the color inks is the
ink-jet recording ink according to any one of (1) to (4).
(7) The ink-jet recording ink according to (4), wherein the one
or more barrier layers have a thickness of 10p.m. or less.
(8) An ink cartridge including a container to house the ink-jet
recording ink according to any one of (1) to (4).

(9) An ink-jet recording method including performing
recording with the use of the ink-jet recording ink media set
according to (5), wherein the amount of the ink-jet recording ink
attached onto the recording medium is 15g/m2 or less.
(10) The ink-jet recording method according to (9), further
including jetting the ink-jet recording ink so as to form an image
on the recording medium, by applying a stimulus to the ink-jet
recording ink.
(11) The ink-jet recording method according to (10), wherein


the stimulus is at least one selected from heat, pressure,
vibration and light.
(12) An ink-jet recording apparatus including an ink jetting
unit configured to jet the ink-jet recording ink according to any
one of (2) to (4) toward an ink-jet recording medium for pigment
ink and perform printing such that the amount of the ink-jet
recording ink attached onto the recording medium is 15g/m2 or
less, wherein the ink-jet recording ink, the ink-jet recording
medium and an ink cartridge are installed in the ink-jet
recording apparatus, wherein the ink-jet recording medium,
includes a support containing cellulose pulp, and one or more
barrier layers on one or both surfaces of the support, with the one
or more barrier layers containing 30% by mass or more of an
inorganic pigment that is different from an alumina hydrate and
that has a refractive index of 1.5 or greater, and containing 10%
by mass or less of a pigment that has a refractive index of less
than 1.5, and wherein the ink cartridge houses the ink-jet
recording ink.
(13) An ink-jet recording apparatus including a recording head,
and a unit configured to reverse paper and thereby enable
double-sided printing, wherein the ink-jet recording ink
according to any one of (1) to (4) is ejected as droplets from the
recording head so as to record an image on the paper.
According to the present invention, problems in related art


can be solved, and the following can be provided- an ink-jet
recording ink, an ink-jet recording ink set, an ink-jet recording
ink media set, an ink cartridge, an ink-jet recording method and
an ink-jet recording apparatus, wherein a combination of a
fluorochemical surfactant having a specific structure and a
pigment serving as a colorant on plain paper makes it possible to
increase image density, improve color development and reduce
color bleeding on the plain paper; a combination of the ink-jet
pigment ink and an ink-jet recording medium shown in the
present invention makes it possible to obtain printed matter
which is inexpensive, excellent in quality, superior in density,
glossiness and image reliability and comparable with commercial
printed matter; and it is possible to reduce beading and secure
superior reliability in terms of ejection stability, storage stability
and the like.
Brief Description of Drawings
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 of FIG. 1 with the inclusion of a case (outer covering).
FIG. 3 is an explanatory perspective view exemplarily
showing an ink-jet recording apparatus of the present invention
when a cover provided at an ink cartridge loading section is open.


FIG. 4 is a schematic structural diagram, for explaining the
overall structure of an ink-jet recording apparatus of the present
invention.
FIG. 5 is a schematic enlarged view showing one example
of an ink-jet head of the present invention.
FIG. 6 is an enlarged view showing elements of one
example of an ink-jet head of the present invention.
FIG. 7 is an enlarged cross-sectional view showing main
parts of one example of an ink-jet head of the present invention.
Best Mode for Carrying Out the Invention
The following explains in detail an ink-jet recording ink,
an ink-jet recording ink set, an ink-jet recording ink media set,
an ink cartridge, an ink-jet recording method and an ink-jet
recording apparatus of the present invention.
As a result of carrying out a series of earnest examinations
to achieve the aim of increasing image density, improving color
development and reducing color bleeding on plain paper, the
present inventors have found that since an ink-jet recording ink
of the present invention includes a pigment as a colorant and is
combined with a fluorochemical surfactant having a specific
structure, the ink-jet recording ink has head ejection stability
and is excellent in increasing image density, improving color
development and reducing color bleeding on plain paper. As to


the foregoing, it is inferred that when included in the ink, the
fluorochemical surfactant for use in the present invention gives
the ink great wettability, makes ink components other than the
colorant quickly penetrate into the plain paper after ink droplets
have come into contact with the plain paper, and makes the
colorant remain on the paper surface, thereby yielding an
increase in image density; also, it is inferred that since the ink's
great wettability produces a strong effect of making the colorant
remain uniformly on the plain paper, the uniformity of a solid
image portion or the like improves, thereby yielding an
improvement in color development. Additionally, it is inferred
that the uniform penetration of the ink components other than
the colorant into the plain paper promotes uniform fixation of the
colorant and reduces bleeding between colors. Further, it has
been found that this fluorochemical surfactant is, due to its
structure, superior in leveling ability at the gas-liquid interface,
very effective in preventing foaming of the ink, and superior in.
supplying the ink to a head, and has a great effect on ejection
stability in high-speed printing, etc.
As to fluorochemical surfactants in general, there has been
concern over their safety and effects on the environment (e.g.
accumulation of PFOS or PFOA in the human body) in recent
years, and the effects are viewed as an environmental problem.
However, the fluorochemical surfactant used in the present


invention is accepted by United States Environmental Protection
Agency (EPA) as safe for the environment, and so the
fluorochemical surfactant can be suitably used in terms of safety
as well. The amount of at least one fluorochemical surfactant
selected from compounds represented by Structural Formula (1)
above, in the ink-jet recording ink is preferably 0.01% by mass to
10% by mass, more preferably 0.1% by mass to 5% by mass.
When the amount is less than 0.01% by mass, there is no
remarkable effect on improvement in color development in terms
of image quality. When the amount is greater than 10% by mass,
there is an adverse effect on dispersion of the pigment serving as
a colorant in the ink, which lowers dispersion stability and
causes thickening of the ink and flocculation of particles, and
thus there is an adverse effect on the storage stability of the ink.
[Recording Media]
Next, recording media will be explained.
Generally, ink-jet coated paper (an ink-jet medium) for
realizing a high-quality image is designed such that an ink
receiving layer (coat layer) formed of an inorganic pigment is
present on or near a base surface, and an image is formed as the
ink receiving layer itself absorbs ink (or ink penetrates into the
ink receiving layer). This is deeply related to the fact that
ink-jet recording technologies have been developed based upon
dye inks.


In essence, dyes are color-developing substances that are
supposed to penetrate into substances with affinity and to bond
with them (covalent bond, ionic bond or van der Waals bond),
whereas pigments have no (or little) bonding force and need to be
bonded by adhesives (binders). Therefore, in the case of ink-jet
recording using dye ink, ink receiving layer material is, in effect,
dyed. This fact has prompted technological concepts, for
example an idea of dyeing an ink receiving layer as uniformly as
possible or dyeing ink receiving layer material as much as
possible using ink-jet ink; in order to obtain high-density,
high-quality images, techniques for soaking ink-jet ink deeper
into ink receiving layers, techniques for combining ink-jet ink
and ink receiving layer material as firmly as possible, and
techniques for achieving a favorable balance between ink
absorbability and color-developing ability have been developed.
As described above, the most common method for
producing present-day ink-jet paper includes forming an
ink-absorbing layer which is porous and highly transparent,' to
realize this method, it is necessary to primarily use a material
having a low refractive index and a large specific surface area,
and in reality the ink-jet paper inevitably depends upon an
expensive material such as silica or an alumina hydrate and an
elaborate production method. It goes without saying that
printing costs are very high, and application of the ink-jet paper


to mass printing, etc. is difficult.
As a result of carrying out earnest studies on a lower-cost
ink-jet recording method in light of the foregoing, the present
inventors have devised a low-cost image forming method based
upon a novel design concept, realized by combining a highly
penetrative pigment ink and a medium having low ink-absorbing
properties, as opposed to a conventional medium.
Specifically, the present inventors have found that a
favorable balance between sufficient image density and drying
capability can be achieved with a small amount of ink in the
following manner; by conducting printing onto a recording
medium whose ink-absorbing properties (ink penetration
properties) have been reduced so as to prevent a pigment as a
coloring material in the ink from soaking into the recording
medium as much as possible, using a small amount of extremely
penetrative pigment ink, only a solvent (water and an organic
solvent) that is a component of the ink is selectively soaked into a
support, and only the coloring material (pigment) in the ink is
made to remain efficiently on the medium surface.
The recording medium having reduced ink-absorbing
properties in the present invention can be realized by providing
(for example applying) a layer for preventing pigment
penetration (barrier layer) on a support composed mainly of
cellulose pulp, in other words on a paper substrate. By


approximating the appearance of this barrier layer to that of
printing paper, it is even possible to obtain printed matter which
is similar in quality to ordinary commercial printed matter. It
has been found that by limiting the pore size, diameter, thickness,
etc. of the barrier layer, the ink penetration properties (barrier
properties) can be reduced to a desired level.
In order to promote separation of the pigment and the ink
solvent in the ink, the thickness of the barrier layer needs to be
less than or equal to a predetermined thickness; specifically, the
thickness of the barrier layer needs to be 10µm or less, preferably
5µm or less. When the thickness is greater than lOum,
penetration of the ink solvent takes a long time, beading,
bleeding and the like easily arise, causing the image quality to
lower, and degradation of drying capability easily causes offset
and the like. Also, since it is necessary to make the barrier
layer thin and therefore to prevent offset (a phenomenon in which
the color of a coloring material printed on one side of paper can
also be seen from the other side) of the coloring material, for
example, an inorganic pigment having a high refractive index and
high concealing properties needs to be contained in large
amounts in the barrier layer, as opposed to a conventional ink"jet
medium; specifically, it is necessary for the barrier layer to
contain 30% by mass or more of the inorganic pigment having a
refractive index of 1.5 or greater. Silica, a material that has a


low refractive index and low concealing properties and that is
used for conventional ink-jet media, may be contained in the
barrier layer; however, if a highly transparent pigment is
contained in large amounts in the barrier layer, offset intensifies
and the cost increases; therefore, it is necessary for the amount of
silica to be 10% by mass or less. Thus, by using a material
having a high refractive index as a white pigment that forms the
barrier layer, offset can be reduced even when the barrier layer is
made thin, and the cost can be further lowered.
Additionally, some alumina hydrates can be used as
pigments having high refractive indices; however, if a material
which absorbs too much oil such as an alumina hydrate is
contained in large amounts in the barrier layer, the ink solvent
does not easily move from the barrier layer to the substrate. An
alumina hydrate having absorbed a large amount of solvent is not
desirable in the present invention because when stored for a long
period of time, it induces discoloration and image bleeding
related to migration of a pigment.
The function necessary for the barrier layer in the present
invention is to separate the pigment and the solvent in the ink
from each other and make only the solvent penetrate into the
substrate. In order for that to take place, it is desirable that the
barrier layer have small holes (pores). If the barrier layer has
no pores whatsoever, penetration of solvent components of the ink


takes place slowly, thereby easily causing a phenomenon in which
the ink does not dry. Conversely, if pores are too large in
diameter, or the number of pores is too large, the function of
separating the pigment and the solvent in the ink from each other
degrades, the image density decreases, and the pigment which is
present on the medium surface after printing migrates into the
medium with time, causing a change in color. Therefore, it is
necessary for the pores to be 1µm or less in diameter, and the
pores preferably occupy 40% or less of the medium surface in
area.
The pore diameter and the area of the pores with respect to
the area of the medium surface can be measured through surface
observation in accordance with SEM. The pore diameter and the
area ratio can be calculated by binarizing an image of a pore
portion base upon a photograph of the surface. In the present
invention, the field-emission scanning electron microscopes
JSM-7400F (manufactured by JEOL Ltd.) and FE-SEM S-4200
(manufactured by Hitachi, Ltd.) are used as SEMs, and
POPIMAGING (ver. 3.51) (manufactured by Digital being kids Co.,
Ltd.) is used for image processing.
[Ink]
A pigment ink essential for the present invention is
required to be extremely penetrative; at 25°C, the pigment ink
has a surface tension of 20mN/m to 35mN/m, preferably 23mN/m


to 33mN/m, more preferably 25mN/m to 30mN/m. Also, at 25°C,
the pigment ink has a viscosity of 5mPa-s or greater, preferably
5mPa-s to 15mPa-s, more preferably 5mPas to 10mPa-s. As for a
surfactant used in the present invention, one or more
fluorochemical surfactants each having a specific structure are
contained in the ink. The total amount of a water-dispersible
resin (A) and a colorant (B) present in the ink is preferably 5% by
mass to 40% by mass, and the mass ratio (A)/(B) of the
water-dispersible resin (A) to the colorant (B) is preferably in the
range of 0.5 to 4, more preferably in the range of 1 to 2.5.
The following explains components of the ink essential for
the present invention.
The recording ink of the present invention includes water,
a water-soluble organic solvent, a pigment as a colorant, and a
fluorochemical surfactant having a specific chemical structure,
and further includes other components in accordance with the
necessity.
For the fluorochemical surfactant having the specific
chemical structure, at least one selected from compounds
represented by Structural Formula (1) below is used.



Structural Formula (1)
(In Structural Formula (1), R1 denotes any one of a hydrogen
atom, an alkyl group and a perfluoroalkyl group, R2 denotes any
one of a hydrogen atom, an alkyl group and a fluorine -containing
group, Rf denotes a fluorine-containing group, and m and n each
denote an integer of 1 or greater.)
In Structural Formula (1), Rf denotes a
fluorine-containing group, particularly preferably a
perfluoroalkyl group.
The perfluoroalkyl group is preferably a perfluoroalkyl
group having 1 to 10 carbon atoms, more preferably a
perfluoroalkyl group having 1 to 4 carbon atoms in view of safety,
and examples thereof include -CF3, -CF2CF3, -CF2CF2CF3 and
-CF2CF2CF2CF3, with particular preference being given to -CF3
and -CF2CF3. Each of R1 and R2 may be a hydrogen atom, an
alkyl group such as methyl group, ethyl group, propyl group or
butyl group, or a fluorine-containing group such as -CF3,
-CF2CF3, -CF2CF2CF3 or -CF2CF2CF2CF3, with particular

preference being given to -CF3 and -CF2CF3 in terms of
improvement in image quality. As to m and n, it is desirable
that m be an integer of 6 to 25 and n be an integer of 1 to 10, and
it is more desirable that m be an integer of 10 to 22 and n be an
integer of 4 to 8 in terms of tbe dispersion stability of the pigment
as a colorant and tbe storage stability of the ink.
Such a fluorochemical surfactant is different in structure
from fluorochemical surfactants (each of which is a
fluorochemical surfactant having ammonium base sulfonates or
hydroxy groups at both terminals of a main chain) described in
PCT/US2006/029862 and US2007/0088101 A; examples of such a
fluorochemical surfactant include POLYFOX PF-151N and
AT-1202 produced by OMNOVA Solutions Inc., which can be
effectively used in the present invention.
Also as to the ink of the present invention, the mass ratio
of the colorant (B) to the water-dispersible resin (A) is reduced
and at least one type of fluorochemical surfactant having a
specific structure is contained as a surfactant in the ink so as to
improve the wettability and penetrability of the ink; uniformity
of coloring material on paper is produced; and at least one
selected from an anionic self-emulsifiable ether-based
polyurethane resin emulsion and an acrylic-silicone resin
emulsion is contained in the water-dispersible resin (A); thus,
printed matter capable of being firmly fixed onto an inexpensive


medium, of the present invention and comparable with
commercial printed matter can be achieved by a combination of
the ink and the medium.
For the water-dispersible resin (A) able to be used in the
present invention, at least one selected from a polyurethane resin
emulsion and an acrylic-silicone resin emulsion, or a combination
thereof is suitable. Also, the water-dispersible resin (A) is
present as an O/W emulsion when used as a raw material in
preparation of the ink or after the ink has been prepared.
When at least one selected from a polyurethane resin
emulsion and an acrylic-silicone resin emulsion is used, the
emulsion/emulsions is/are present in the ink by a total of 1% by
mass to 40% by mass, preferably a total of 1% by mass to 20% by
mass.
Polyurethane resin emulsions are classified into emulsions
produced by emulsifying ordinary polyurethane resins that are
relatively hydrophilic with the external use of emulsifiers, and
self-emulsifiable emulsions in which functional groups serving as
emulsifiers are introduced into resins themselves by
copolymerization or the like. In terms of a combination of the
water-dispersible resin (A) and the pigment, etc. able to be used
in the ink of the present invention, it is anionic self-emulsifiable
polyurethane resin emulsions that are always superior in
dispersion stability. In the case where an anionic


self-emulsifiable polyurethane resin emulsion is used, it is
desirable that the polyurethane resin be based upon an ether
rather than a polyester or polycarbonate in terms of the fixation
and dispersion stability of the pigment. For some unknown
reason, in many cases, polyurethane resins that are not based
upon ethers have little resistance to solvent and thus easily cause
flocculation of particles and a rise in ink viscosity when ink is
stored at high temperatures.
The ether polyurethane resin emulsion has an average
particle diameter of 300nm or less, preferably 100nm or less,
more preferably 80nm or less. In particular, by reducing its
average particle diameter to 100nm or less, it is possible to
improve the reliability of an ink-jet printer, for example ink
ejection stability after the ink-jet printer has been left unused for
a long period of time.
The glass transition temperature of the ether
polyurethane resin emulsion is preferably in the range of -50°C
to 150°C, more preferably in the range of -10°C to 100°C. For
some unknown reason, when the glass transition temperature is
higher than 150°C, the ether polyurethane resin emulsion is hard
like glass with respect to its film forming properties, but a
printed portion, formed as particles of the pigment and the ether
polyurethane resin emulsion simultaneously come into contact
with an image support, has unexpectedly little abrasion


resistance; when the glass transition temperature is 150°C or
lower, the ether polyurethane resin emulsion is soft like rubber
with respect to its film forming properties, but a printed portion
is superior in abrasion resistance. Meanwhile, when the glass
transition temperature is lower than -50°C, the film is too soft
and a printed portion is inferior in abrasion resistance. Thus, it
has been found that when there is no difference in the amount of
the ether polyurethane xesin emulsion added, the range of -50°C
to 150°C is suitable for its glass transition temperature in terms
of the abrasion resistance of printed matter. Additionally, the
glass transition temperature of the resin mentioned in the
present invention can be measured in accordance with either DSC
(differential scanning calorimetry) or TMA (thermo-mechanical
analysis).
The minimum film forming temperature of the ether
polyurethane resin emulsion is preferably lower than or equal to
room temperature, more preferably lower than or equal to 25°C.
When the ether polyurethane resin emulsion is formed into a film
at a temperature which is lower than or equal to room
temperature, particularly at a temperature which is lower than
or equal to 25°C, it is favorable because binding of paper fiber
automatically proceeds without the need to heat, dry, etc. an
image support where an image has been formed.
Here, the "minimum film forming temperature (MFT)" is


defined as the minimum temperature at which a continuous
transparent film is formed, when aqueous emulsion particles
obtained by dispersing ether polyurethane resin emulsion
particles into water are thinly cast onto a metal plate made of
aluminum or the like and the temperature is increased.
Next, acrylic-silicone resin emulsions able to be used in
the present invention will be described.
The acrylic-silicone resin emulsion of the present
invention is a silicone-modified acrylic resin emulsion which can
be obtained by polymerizing an acrylic monomer and a silane
compound in the presence of an emulsifier.
Examples of the acrylic monomer include acrylic acid ester
monomers such as methyl acrylate, ethyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, acryloyl
morpholine and N,N'-dimethylaminoethyl acrylate; methacrylic
acid ester monomers such as methyl methacrylate, ethyl
methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate,
2-hydroxyethyl methacrylate and N.N'-dimethylaminoethyl
methacrylate," amide acrylates such as N-methylolacrylamide and
methoxymethylacrylamide; and carboxylic acid-containing
monomers such as maleic acid, fumaric acid, itaconic acid, acrylic
acid and methacrylic acid.
Examples of the emulsifier of the present invention
include alkylbenzenesulfonic acids and salts thereof,


dialkylsulfosuccinic acid esters and salts thereof,
alkylnaphthalenesulfonic acids and salts thereof, formalin
condensates of alkylnaphthalene sulfonates, higher fatty acid
salts, sulfonates of higher fatty acid esters,
polyoxypropylene-polyoxyethylene condensates of
ethylene diamine, sorbitan fatty acid esters and salts thereof,
aromatic/aliphatic phosphoric acid esters and salts thereof,
dodecylbenzene sulfonates, dodecyl sulfates, lauryl sulfates,
dialkylsulfosuccinic acid salts, polyoxyethylene alkylphenyl ether
sulfates, polyoxyethylene alkylpropenylphenyl ether sulfates,
alkylphenyl ether disulfonates, polyoxyethylene alky 1 phosphates,
polyoxyethylene alkyl ether acetates, polyoxyethylene lanolin
alcohol ethers, polyoxyethylene lanolin fatty acid esters, lauryl
alcohol ethoxylates, lauryl ether sulfates, lauryl ether phosphoric
acid esters, sorbitan fatty acid esters, fatty acid diethanol amides
and formalin condensates of naphthalene sulfonic acid. Here,
examples of the salts include sodium and ammonium.
Also, as the emulsifier of the present invention, a reactive
emulsifier having an unsaturated double bond may be used as
well. Examples of the reactive emulsifier include ADEKA
REASOAP SE, NE and PP (produced by Asahi Denka Co., Ltd.),
LATEMUL S-180 (produced by Kao Corporation), ELEMINOL
JS-2 and B,S-30 (produced by Sanyo Chemical Industries, Ltd.)
and AQUALON RN-20 (produced by Dai-Ichi Kogyo Seiyaku Co.,


Ltd.).
Examples of the silane compound include
tetramethoxysilane, methyltrimethoxysilane,
dimethyldimethoxysilane, phenyltrimethoxysilane,
diphenyldimethoxysilane, tetraethoxysilane,
methyltriethoxysilane, dimethyldiethoxysilane,
phenyltriethoxysilane, diphenyldiethoxysilane,
hexyltrimethoxysilane, hexyltriethoxysilane,
decyltrimethoxysilane and trifluoropropyltrimethoxysilane.
Also, monomers generally known as silane coupling agents
may be used as well, and examples thereof include
vinyltrichlorsilane, vinyltrimethoxysilane, vinyltriethoxysilane,
p -styryltrimethoxysilane,
3-methacryloxypropylmethyldimethoxysilane,
3-methacryloxypropyltrimethoxy silane,
3-methacryloxypropylmethyldiethoxysilane,
3-methacryloxypropyltriethoxysilane,
3-acryloxypropyltrimethoxysilane,
N-2(aminoethyl)3-aminopropylmethyldimethoxysilane,
N-2(aminoethyl)3-aminopropyltrimethoxysilane,
N-2(aminoethyl)3-aminopropyltriethoxysilane,
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine,
N-phenyl-3-aminopropyltriraethoxysilane, hydrochlorides of


3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane,
3-mercaptopropylmethyldimethoxysilane,
3-mercaptopropyltrimethoxysilane,
bis(triethoxysilylpropyl)tetrasulfide and
3-isocyanatepropyltriethoxysilane.
In the present invention, the term "hydrolyzable silyl
group" denotes a silyl group which contains a hydrolyzable group,
and examples of the hydrolyzable group include alkoxy groups,
mercapto groups, halogen groups, amide groups, acetoxy group,
amino groups and isopropenoxy group.
A silyl group hydrolyzes into a silanol group, and the
silanol group dehydrates and condenses to yield a siloxane bond.
In the silicone-modified acrylic resin used for the ink of the
present invention, it is desirable that the hydrolyzable silyl
group hydrolyze as a result of polymerization reaction and finally
disappear. If the hydrolyzable silyl group remains, it is not
favorable because of degradation of the storage stability of the
ink that has been prepared.
Fine particles of the silicone-modified acrylic resin
preferably have an average diameter of 10nm to 300nm, more
preferably 40nm to 200nm. When the ink is synthesized such
that the average particle diameter is less than 10nm, the
viscosity of the resin emulsion increases, and thus it is difficult to


yield an ink viscosity which enables a printer to eject the ink.
When the average particle diameter is greater than 300nm, the
particles clog a nozzle of the printer, and thus ejection failure
arises.
The amount of silicone derived from the silicone-modified
acrylic resin, contained in the ink of the present invention is
preferably in the range of 100ppm to 400ppm. When the amount
of silicone is less than 100ppm, it is impossible to obtain a coating
film superior in abrasion resistance or marker resistance. When
the amount of silicone is greater than 400ppm, there is an
increase in hydrophobic property and a decrease in the stability
of the silicone in the aqueous ink.
The minimum film forming temperature of the
silicone-modified acrylic resin used in the ink of the present
invention is preferably 20°C or lower. When the minimum film
forming temperature is higher than 20°C, sufficient fixation of
the ink on a printing medium cannot be yielded. In other words,
if a printed portion is scratched or marked with a marker, for
example, the pigment becomes separated from the printed portion,
thus smearing the printing medium.
Next, the following provides an explanation of why the
total amount of the water-dispersible resin (A) and the colorant
(B) of the present invention present in the ink is 5% by mass to
50% by mass, and the mass ratio (A)/(B) of the water-dispersible


resin. (A) to the colorant (B) is in the range of 0.5 to 4.
Printed matter capable of being firmly fixed onto the
inexpensive medium in the present invention and comparable
with commercial printed matter can be achieved by a combination
of the ink and the medium described in the present invention," as
for important factors concerning the ink in the present invention,
it has been found in the present invention thatthe total solid
content of the water-dispersible resin (A) and the colorant (B) in
the ink and the ratio of the water-dispersible resin (A) to the
colorant (B) are necessary factors in achieving the object.
Specifically, the total solid content of the water-dispersible
resin (A) and the colorant (B) in the ink needs to be 5% by mass to
40% by mass. When the total solid content is less than 5% by
mass, the ink is not sufficiently fixed onto the medium used in
the present invention, for example. When the total solid content
is greater than 40% by mass, the ink viscosity becomes so high
that there is an adverse effect on the reliability of the ink in
terms of ink ejection stability and the like. Additionally, the
total solid content is preferably 5% by mass to 20% by mass. A
pigment that contains resin in a dispersed manner or that is
coated with resin can also be used depending upon the type of a
coloring material described below, in which case a resin
dispersant or the coating resin, and the water-dispersible resin
(A) are added together as the resin solid content (A).


As for the fact that the mass ratio (A)/(B) of the
water-dispersible resin. (A) to the colorant (B) is in the range of
0.5 to 4, when the mass ratio is less than 0.5, the ink is not
sufficiently fixed onto the medium used in the present invention,
for example; when the mass ratio is greater than 4, the
concentration of the coloring material is so low with respect to
that of the resin that there are degradations of image quality
such as a decrease in image density and a reduction in image
uniformity. For this reason, in view of the medium used in the
present invention, important factors concerning the ink used in
the present invention are that the total amount of the
water-dispersible resin (A) and the colorant (B) in the ink is 5%
by mass to 40% by mass, and that the mass ratio (A)/(B) of the
water-dispersible resin (A) to the colorant (B) is in the range of
0.5 to 4. It is more desirable that the mass ratio be in the range
of 1 to 2.5 in terms of image quality.
Next, components constituting the ink of the present
invention, and compositions thereof will be described.
Specific examples of the water-soluble organic solvent
include the following compounds.
polyhydric alcohols such as ethylene glycol, diethylene
glycol, triethylene glycol, propylene glycol, dipropylene glycol,
tripropylene glycol, tetraethylene glycol, polyethylene glycol,
polypropylene glycol, 1,3-butanediol, 3-methyl-1,3-butanediol,


2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol,
2-methyl-2,4-pentanediol, petriol and
3-methoxy-3-methyl-1-butanediol;
polyhydric alcohol alkyl ethers such as ethylene glycol
monoethyl ether, ethylene glycol monobutyl ether, diethylene
glycol m'onomethyl ether, diethylene glycol monoethyl ether,
diethylene glycol monobutyl ether, tetraethylene glycol
monomethyl ether and propylene glycol monoethyl ether;
polyhydric alcohol aryl ethers such as ethylene glycol
monophenyl ether, ethylene glycol monobenzyl ether, dipropylene
glycol monobutyl ether, tripropylene glycol monobutyl ether,
diethylene glycol isobutyl ether, triethylene glycol isobutyl ether
and diethylene glycol isopropyl ether;
nitrogen-containing heterocyclic compounds such as
2-pyrrolidone, N-methyl-2-pyrrolidone,
N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone,
s-caprolactam and y-butyrolactone;
amides such as N-methylformamide and
N,N-dimethylformamide;
amines such as monoethanolamine, diethanolamine,
triethanolamine, monoethylamine, diethylamine and
triethylamine;
sulfur-containing compounds such as dimethyl sulfoxide,


sulfolane, thodiethanol and thiodiglycol; and
propylene carbonate and ethylene carbonate.
Among these organic solvents, particular preference is
given to glycerin, ethylene glycol, diethylene glycol, triethylene
glycol, propylene glycol, dipropylene glycol, tripropylene glycol,
1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol,
tetraethylene glycol, 1,6-hexanediol, 2-methyl-2,4-pentanediol,
polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol,
thiodiglycol, 2-pyrrolidone, N-methyl-2-pyrrolidone,
N-hydroxyethyl-2-pyrrolidone and
1,3-dimethyl-2-imidazolidinone. These compounds make it
possible to obtain excellent effects with respect to solubility and
prevention of ejection failure caused by moisture evaporation.
The pigment ink essential for the present invention
includes at least water, a colorant in the form of particles, a
fixative for the colorant, and a water-soluble organic solvent, also
includes a wetting agent and a surfactant, and further includes
other components in accordance with the necessity.
As to the object of the present invention, a fluorochemical
surfactant having a specific structure is used as the surfactant,
the mass ratio of the colorant (B) to the water-dispersible resin
(A) is lowered, and at least one selected from an anionic
self-emulsifiable ether-based polyurethane resin emulsion and an
acrylic-silicone resin emulsion is contained in the


water-dispersible resin; thus, printed matter capable of being
firmly fixed onto the inexpensive medium of the present
invention and comparable with commercial printed matter can be
achieved by a combination of the ink and the medium.
Examples of the colorant (B) include dyes such as
water-soluble dyes, oil-soluble dyes and disperse dyes, and the
pigment. Oil-soluble dyes and disperse dyes are preferable in
terms of adsorption and encapsulation, while the pigment is
preferable in terms of the light resistance of images obtained.
It is desirable that each of the dyes dissolve in an organic
solvent, e.g. a ketone-based solvent, at a rate of 2g/l or greater,
more desirably at a rate of 20g/l to 600g/l, in view of the fact that
the dyes can be efficiently encapsulated in fine polymer particles.
The colorant (B) used in the present invention will be
explained below.
Examples of the pigment used in the present invention
include the following; as a black pigment, carbon black." as color
pigments, anthraquinone, phthalocyanine blue, phthalocyanine
green, diazo, monoazo, pyranthron, perylene, heterocyclic yellow,
quinacridone and (thio)indigoid. Typical examples of
phthalocyanine blue include copper phthalocyanine blue and
derivatives thereof (Pigment Blue 15). Typical examples of
quinacridone include Pigment Orange 48, Pigment Orange 49,
Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment


Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19
and Pigment Violet 42. Typical examples of anthraquinone
include Pigment Red 43, Pigment Red 194 (perinone red),
Pigment Red 216 (brominated pyranthron red) and Pigment Red
226 (pyranthron red). Typical examples of pyrelyne include
Pigment Red 123 (vermillion), Pigment Red 149 (scarlet),
Pigment Red 179 (maroon), Pigment Red 190 (red), Pigment
Violet, Pigment Red 189 (yellow shade red) and Pigment Red 224.
Typical examples of thioindigoid include Pigment Red 86,
Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red
198, Pigment Violet 36 and Pigment Violet 38. Typical examples
of heterocyclic yellow include Pigment Yellow 117 and Pigment
Yellow 138. Other suitable examples of coloring pigments are
described in "The Colour Index, third ed., The Society of Dyers
and Colourists, 1982", for instance.
For the pigment in the ink of the present invention, it is
possible to use a pigment that is provided with at least one
hydrophilic group, which is bonded to the pigment surface
directly or via other atomic group, and that can therefore be
stably dispersed without using a dispersant. The pigment of the
present invention provided with a hydrophilic group, which is
introduced onto the pigment surface, preferably has ionic
properties, and an anionically charged pigment or a cationically
charged pigment is suitable for the pigment.


Examples of anionic hydrophilic groups include -COOM,
-SO3M, -PO3HM, -PO3M2, -SO2NH2 and -SO2NHCOR (in these
formulae, M denotes a hydrogen atom, an alkali metal,
ammonium or an organic ammonium, and R denotes an alkyl
group having 1 to 12 carbon atoms, a phenyl group that may have
a substituent, or a naphthyl group that may have a substituent).
In the present invention, among these, use of—COOM and —SO3M,
each of which is bonded to the pigment surface, is particularly
preferable. Examples of methods for obtaining an anionically
charged pigment include a method of oxidizing a pigment with
sodium hypochlorite, a method utilizing sulfonation, and a
method of making a pigment and a diazonium salt react together;
however, it should be noted that the present invention may
employ other methods.
As the hydrophilic group bonded to the surface of the
cationically charged pigment, a quaternary ammonium group can
be used, for instance. Ideally, a.pigment provided with at least
one of the following quaternary ammonium groups, which is
bonded to the pigment surface, is used as the pigment.
As to the pigment used in the ink of the present invention,
a pigment dispersion in which the pigment is dispersed in an
aqueous medium by a dispersant can also be used. Suitable
examples of the dispersant include known dispersants used in
preparing pigment dispersion solutions; specifically, the suitable


examples include the following compounds.
Polyacrylic acid, polymethacrylic acid, acrylic
acid-acrylonitrile copolymers, vinyl acetate-acrylic acid ester
copolymers, acrylic acid-acrylic acid alkyl ester copolymers,
styrene-acrylic acid copolymers, styrene-methacrylic acid
copolymers, styrene-acrylic acid-acrylic acid alkyl ester
copolymers, styrene-methacrylic acid-acrylic acid alkyl ester
copolymers, styrene-crmethylstyrene-acrylic acid copolymers,
styrene-crmethylstyrene-acrylic acid copolymers-acrylic acid
alkyl ester copolymers, styrene-maleic acid copolymers,
vinylnaphthalene-maleic acid copolymers, vinyl acetate-ethylene
copolymers, vinyl acetate-fatty acid vinyl ethylene copolymers,
vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic
acid copolymers and vinyl acetate-acrylic acid copolymers.
A nonionic dispersant or an anionic dispersant used to
disperse the pigment may be suitably selected according to the
type of the pigment or the ink formulation." examples of the
nonionic dispersant include polyoxyethylene alkyl ethers such as
polyoxyethylene lauryl ether, polyoxyethylene myristyl ether,
polyoxy ethylene cetyl ether, polyoxyethylene stearyl ether and
polyoxyethylene oleyl ether; polyoxyethylene alkylphenyl ethers
such as polyoxyethylene octylphenyl ether and polyoxyethylene
nonylphenyl ether; polyoxyethylene crnaphthyl ether,
polyoxyethylene p-naphthyl ether, polyoxyethylene


monostyrylphenyl ether, polyoxyethylene distyrylphenyl ether,
polyoxyethylene alkylnaphthyl ether, polyoxyethylene
monostyrylnaphthyl ether, polyoxyethylene distyrylnaphthyl
ether, and polyoxyethylene-polyoxypropylene block copolymers.
Also, it is possible to use dispersants produced by replacing part
of the polyoxyethylene of these dispersants with
polyoxypropylene, and dispersants produced by condensing
aromatic ring-containing compounds such as polyoxyethylene
alkylphenyl ethers, using formalin or the like.
The HLB of the nonionic dispersant is preferably in the
range of 12 to 19.5, more preferably in the range of 13 to 19.
When the HLB is less than 12, the dispersant is not compatible
with the dispersion medium, and thus the dispersion stability
tends to degrade. When the HLB is greater than 19.5, the
dispersant does not easily adsorb to the pigment, and thus the
dispersion stability tends to degrade in this case as well.
It is particularly desirable that the nonionic dispersant be
selected from compounds represented by Structural Formula (2)
below. By dispersing the pigment with the use of any of these
compounds, the average particle diameter of the pigment becomes
small, and the particle size distribution can be made narrower.
The polymerization degree n of the ethylene oxide moiety in
Structural Formula (2) given below is preferably in the range of
20 to 200, more preferably in the range of 25 to 60. In the case


where a is less than 20, the dispersion stability lowers, the
average particle diameter of the pigment becomes large, and the
color saturation of images tends to decrease. In the case where
n is greater than 200, the viscosity of the pigment dispersion
becomes high, the ink viscosity becomes high as well when an ink
has been prepared, and printing based upon an ink-jet recording
method tends to become difficult to achieve.

Structural Formula (2)
(In Structural Formula (2), E denotes an alkyl group having 1 to
20 carbon atoms, m denotes an integer of 0 to 7, and n denotes an
integer of 20 to 200.)
Examples of the alkyl group include methyl group, ethyl
group, n-propyl group, i-propyl group, n-butyl group, i-butyl
group, t-butyl group, n-pentyl group, i-pentyl group, n-hexyl
group, i-hexyl group, n-heptyl group, i-heptyl group, n-octyl
group, i-octyl group, n-nonyl group, i-nonyl group, n-decyl group,
i-decyl group, n-undecyl group, i-undecyl group, n-dodecyl group,
i-dodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl

group, cyclohexyl group, cycloheptyl group and cyclooctyl group.
Examples of the anionic dispersant include
polyoxyethylene alkyl ether sulfates, polyoxyethylene
alkylphenyl ether sulfates, polyoxyethylene monostyrylphenyl
ether sulfates, polyoxyethylene distyrylphenyl ether sulfates,
polyoxyethylene alkyl ether phosphates, polyoxyethylene
alkylphenyl ether phosphates, polyoxyethylene monostyrylphenyl
ether phosphates, polyoxyethylene distyrylphenyl ether
phosphates, polyoxyethylene alkyl ether carhoxylates,
polyoxyethylene alkylphenyl ether carhoxylates, polyoxyethylene
monostyrylphenyl ether carhoxylates, polyoxyethylene
distyrylphenyl ether carhoxylates, formalin condensates of
naphthalene sulfonates, formalin condensates of melanin
sulfonates, dialkylsulfosuccinic acid ester salts, disodium alkyl
sulfosuccinates, disodium polyoxyethylene alkylsulfosuccinates,
alkylsulfoacetates, α-olefin sulfonates, alkyl henzene sulfonates,
alkyl naphthalene sulfonates, alkyl sulfonates, N-acylamino acid
salts, acylated dipeptides and soaps. Among these, particular
preference is given to sulfates and phosphates of polyoxyethylene
alkyl ethers, polyoxyethylene alkylphenyl ethers and
polyoxyethylene distyrylphenyl ethers.
The amount of the dispersant added preferably equals 10%
by mass to 50% by mass of the amount of the pigment. When the
amount of the dispersant added equals less than 10% by mass of


the amount of the pigment, the storage stability of the pigment
dispersion and the ink lowers, or dispersion takes a great deal of
time. When the amount of the dispersant added equals more
than 50% by mass of the amount of the pigment, the ink viscosity
becomes too high, and thus the ejection stability tends to lower.
Further, for the colorant (B), a resin-coated colorant can
also he suitably used as explained below.
The resin-coated colorant is made of a polymer emulsion in
which fine polymer particles contain a coloring material which is
insoluble or sparingly soluble in water. In the present
specification, the expression "fine polymer particles contain a
coloring material" means either or both of a state in which the
coloring material is encapsulated in the fine polymer particles,
and a state in which the coloring material is adsorbed on the
surface of the fine polymer particles. In this case, it is not that
all of the coloring material included in the ink of the present
invention needs to be encapsulated in or adsorbed on the fine
polymer particles but that the coloring material may be dispersed
in the emulsion to such an extent that the effects of the present
invention are not impaired. The coloring material is not
particularly limited and may be suitably selected in accordance
with the intended use, as long as it is insoluble or sparingly
soluble in water and can be adsorbed by the polymer. In the
present specification, the expression "insoluble or sparingly


soluble in water" means that not more than 10 parts by mass of
the coloring material dissolves in 100 parts by mass of water at
20°C, whereas the term "dissolve" means that neither division
nor sedimentation of the coloring material is confirmed at the
surface layer or bottom layer of the aqueous solution by visual
observation. Examples of the coloring material include dyes
such as oil-soluble dyes and disperse dyes, and the pigment.
Oil-soluble dyes and disperse dyes are preferable in terms of
adsorption and encapsulation, while the pigment is preferable in
terms of the light resistance of images obtained.
It is desirable that the colorant of the present invention
dissolve in an organic solvent, e.g. a ketone-based solvent, at a
rate of 2g/l or greater, more desirably at a rate of 20g/l to 600g/l,
in view of the fact that the colorant can be efficiently
encapsulated in fine polymer particles. Examples of the polymer
constituting the polymer emulsion include vinyl-based polymers,
polyester-based polymers and polyurethane-based polymers.
Among these, particular preference is given to vinyl-based
polymers and polyester-based polymers, specifically the polymers
disclosed in JP-A Nos. 2000-53897 and 2001-139849. The
amount of the colorant is preferably 10 parts by mass to 200 parts
by mass, more preferably 25 parts by mass to 150 parts by mass,
per 100 parts by mass of the polymer. The fine polymer particles
containing the colorant preferably have an average diameter of


0.16µm or less in the ink.
The amount of the fine polymer particles contained in the
recording ink is preferably 8% by mass to 20% by mass, more
preferably 8% by mass to 12% by mass, as a solid content.
As the colorant used in the present invention, the pigment
is most favorable. Meanwhile, for the resin-coated colorant, a
dye can be used as well. The following shows a set of examples
of water-soluble dyes. It is desirable that those superior in
water resistance and light resistance be used.
Specific examples of the dyes include acid dyes and food
dyes such as C.I. Acid Yellow 17, 23, 42, 44, 79 and 142; C.I. Acid
Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106,
111, 114, 115, 134, 186, 249, 254 and 289; C.I. Acid Blue 9, 29, 45,
92 and 249; C.I. Acid Black 1, 2, 7, 24, 26 and 94; C.I. Food Yellow
3 and 4; C.I. Food Red 7, 9 and 14; and C.I. Food Black 1 and 2.
Specific examples of the dyes include direct dyes such as
C.I. Direct Yellow 1, 12, 24, 26, 33, 44, 50, 86, 120, 132, 142 and
144; C.I. Direct Red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89,
225 and 227; C.I. Direct Orange 26, 29, 62 and 102; C.I. Direct
Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199 and
202; and C.I. Direct Black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77,
154, 168 and 171.
Specific examples of the dyes include basic dyes such as
C.I. Basic Yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32,


36, 40, 41, 45, 49, 51, 53, 63, 64, 65, 67, 70, 73, 77, 87 and 91; C.L
Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46,
49, 51, 52, 54, 59, 68, 69, 70, 73, 78, 82, 102, 104, 109 and 112; CI.
Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67,
69, 75, 77, 78, 89, 92, 93, 105, 117, 120, 122, 124, 129, 137, 141,
147 and 155; and C.I. Basic Black 2 and 8.
Specific examples of the dyes include reactive dyes such as
C.I. Reactive Black 3, 4, 7, 11, 12 and 17; C.I. Reactive Yellow 1, 5,
11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65 and 67; C.I. Reactive
Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96 and 97;
and C.I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80 and
95.
In the present invention, use of a surfactant, notably the
fluorochemical surfactant having a specific structure, makes it
possible to improve the wettability and penetrability of the ink to
recording paper. Fluorochemical surfactants are generally
known to have high foaming properties, and inks containing those
fluorochemical surfactants easily foam in many cases, causing
adverse effects on the ink feeding capability and the ink ejection
stability." however, the fluorochemical surfactant having a
specific structure in the present invention is reduced in foaming
property, superior in ink feeding capability and ink ejection
stability and excellent in safety, and makes it possible to yield
high color-developing properties and uniformity of a coloring


material on the ink-jet recording medium, used in. the present
patent and reduce beading greatly, and thus excellent images can
be obtained. Although details as to why its effectiveness can be
obtained are not known, it is inferred that the fluorochemical
surfactant having a specific structure in the present invention is,
due to its structure, superior in leveling ability, highly effective
in making uniform the surface tension at the gas-liquid interface,
and therefore superior in antifoaming ability, and that the
leveling ability has an effect of evenly dispersing the coloring
material and evenly enlarging image element diameters in a wet
manner on the ink-jet recording medium, which enables beading
to be greatly reduced, thereby making it possible to provide an
ink-jet recording ink, an ink-jet recording ink set, an ink-jet
recording ink media set, an ink cartridge, an ink-jet recording
method and an ink-jet recording apparatus, wherein a
combination of the ink-jet pigment ink and the ink-jet recording
medium shown in the present invention makes it possible to
obtain printed matter which is inexpensive, excellent in quality,
superior in density, glossiness and image reliability and
comparable with commercial printed matter, and it is possible to
secure superior reliability in terms of ejection stability, storage
stability and the like.
In addition to the fluorochemical surfactant represented
by Structural Formula (1) in the present invention, any of the


following fluorochemical surfactants can be used: perfluoroalkyl
sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl
phosphoric acid esters, perfluoroalkyl ethylene oxide adducts,
perfluoroalkyl betaine, perfluoroalkyl amine oxide compounds
and the like. Examples of those which are commercially
available as fluorine-based compounds, easily obtainable and
able to be used in the present invention include SURFLON S-lll,
S-112, S-113, S121, S131, S132, S-141, S-145 and S-386 (produced
by Asahi Glass Co., Ltd.), FLUORAD FC-93, F095, FC-98,
FC-129, FC-135, FC-170C, FO430, FC-431 and FC-4430
(produced by Sumitomo 3M Limited), MEGAFAC F-470, F-1405
and F474 (produced by Dainippon Ink And Chemicals,
Incorporated), ZONYL FS-300, FSN, FSN-100 and FSO (produced
by E. I. du Pont de Nemours and Company), and EFTOP EF-351,
352, 801 and 802 (produced by JEMCO Inc.). Among these,
particular preference is given to ZONYL FS-300, FSN, FSN-100
and FSO (produced by E. I. du Pont de Nemours and Company),
which are excellent in reliability and improving color
development.
Examples of surfactants able to be used in addition to the
above-mentioned fluorochemical surfactants include interfacial
polyoxyethylene alkyl ether acetates, dialkyl sulfosuccinates,
polyoxyethylene alkyl esters, polyoxyethylene alkylphenyl ethers,
polyoxyethylene-polyoxypropylene block copolymers,


polyoxyetnylene alkyl esters, polyoxyethylene sorbitan fatty acid
esters and acetylene glycol-based surfactants. More specifically,
as to anionic surfactants, use of a polyoxyetnylene alkyl ether
acetate and/or a dialkyl sulfosuccinate having a branched alkyl
chain whose carbon chain has 5 to 7 carbon atoms makes it
possible to improve the wettability of the ink to plain paper.
Note that any of these surfactants can be stably present in the
ink of the present invention without disturbing the dispersed
state of ingredients. The amount of any of these other
surfactants added is preferably in the range of 0.0001% by mass
to 5% by mass, and is preferably in the range of 0.01 to 0.5 (as an
active solid content mass ratio) per 1 of the surfactant in
Structural Formula (1).
A polyol having 7 to 11 carbon atoms, used as a penetrant
in the present invention, can be any one of 2-ethyl-1,3-hexanediol
and 2,2,4-trimethyl-1,3"pentanediol, for example. The amount
of the polyol added is preferably in the range of 0.1% by mass to
20% by mass, more preferably in the range of 0.5% by mass to
10% by mass. When the amount is smaller than or equal to the
lower limit, the penetrability of the ink to paper degrades;
therefore, the paper may be smeared when conveyed, as recorded
matter is possibly scratched by a roller, or the paper may be
smeared when reversed for double-sided printing, as the ink is
possibly attached to a conveyance belt, and thus it is impossible


to secure sufficient adaptability to high-speed printing or
double-sided printing-. When the amount is greater than or
equal to the upper limit, there may be an increase in printing dot
diameter, thereby possibly causing the line width of
letters/characters to increase, or causing the image clarity to
decrease.
Examples of additives include an antifungal agent, an
antirust agent and a pH adjuster.
Use of l,2-benzisothiazolin-3-one as an antifungal agent
makes it possible to provide an ink capable of securing reliability
in terms of storage stability, ejection stability and the like, and
superior in antifungal effect. Especially when combined with
the wetting agent of the present invention, the antifungal agent
can be sufficiently effective even if its amount is deemed too
small in related art to reduce the generation of germs or fungi;
thus, by reducing the amount of the antifungal agent added, it
becomes possible to prevent such phenomena as flocculation of
particles and thickening of ink, and so the performance of the ink
can be maintained for a long period of time. As an active
ingredient amount, the amount of 1,2-benzisothiazolin-3-one
added is preferably 0.01 parts by mass to 0.04 parts by mass in
relation to the total amount of the ink. In the case where the
amount is less than 0.01 parts by mass, there is a slight reduction
in antifungal property. In the case where the amount is 0.04


parts by mass or greater, flocculation of particles arises or the ink
viscosity increases by 50% to 100% in comparison with the initial
ink viscosity, when the ink is stored for a long period of time (e.g.
for two years at room temperature, or for one to three months at a
temperature of 50°C to 60°C), for example; hence, there is a
problem with the long-term storage stability of the ink, and the
initial printing performance cannot be maintained.
For the pH adjuster, any substance may be used as long as
it can adjust the pH to 7 or greater without having an adverse
effect on the ink to be prepared.
Examples of the pH adjuster include amines such as
diethanolamine and triethanolamine; hydroxides of alkali metals
such as lithium hydroxide, sodium hydroxide and potassium
hydroxide; ammonium hydroxide, hydroxides of quaternary
ammonium, and hydroxides of quaternary phosphonium;
carbonates of alkali metals such as lithium carbonate, sodium
carbonate and potassium carbonate; and aminopropanediol
derivatives. Aminopropanediol derivatives are water-soluble
organic basic compounds, and examples thereof include
l-amino-2,3-propanediol, l-methylamino-2,3-propanediol,
2-amino-2-methyl-1,3-propanediol and
2-amino-2-ethyl-1,3-propanediol, with particular preference
being given to 2-araino-2-ethyl"1,3-propanediol.
Examples of the antirust agent include acid sulfites,


sodium thiosulfate, ammonium thiodiglycolate,
diisopropylammonium nitrite, pentaerythritol tetranitrate and
dicyclohexylammonium nitrite.
Also, a water-soluble ultraviolet absorber, a water-soluble
infrared absorber or the like may be added to the antirust agent
in accordance with the intended use.
[Ink-jet Recording]
In the present invention, the total amount of the ink needs
to be strictly controlled in order to secure drying properties of the
ink as well as to prevent the coloring material (pigment) in the
ink from soaking into a medium and efficiently make the coloring
material present in the vicinity of the medium surface." if a large
amount of ink is used as in conventional ink-jet recording, the
pigment in the ink possibly penetrates into the medium along
with the ink solvent because the pigment separating ability of a
barrier layer becomes insufficient for the large amount of ink, or
there is possibly a great problem with the ink drying capability
because solvent components of the ink may not penetrate into the
medium as quickly as they should. It has turned out that in
view of the barrier layer performing its function, the total
amount of ink is 15g/m2 at the most, preferably 12g/m2 or less.
The ink amount can be easily adjusted by controlling the amount
of the penetrant (EHD) and the amount of the fluorochemical
surfactant, etc. Also, by reducing the total amount of ink


necessary for printing-, it is possible to make the capacity of an
ink cartridge smaller than in a conventional ink-jet printer and
thus to make an apparatus compact. Additionally, when an ink
cartridge having a size similar to that of a conventional ink
cartridge is used, the rate at which the ink cartridge is replaced
can be reduced, and thus printing becomes possible at a lower
cost. Basically, the smaller the total amount of ink is, the
greater the pigment separating ability of the barrier layer is;
however, if the total amount of ink is too small, there is such a
drawback that the image dot diameter becomes too small after
printing, so that it is desirable to set the total amount of ink
within the above-mentioned range in accordance with a desired
image.
In the present invention, the total amount of ink is
measured in accordance with a weight method. Specifically, a
5cmx20cm rectangle is printed onto a sheet of TYPE 6200
(produced by Ricoh Company, Ltd.), which is PPC paper, then the
weight of the printed sheet is measured immediately after the
printing, the weight of the sheet before the printing is subtracted
from the measured weight, and the obtained value is multiplied
by 100 so as to serve as the total amount of ink.
The highly penetrative ink of the present invention can
also be used for printing onto a conventional void-type ink-jet
medium. It should, however, be noted that since the ink


absorption rate is far higher than in the case where the ink is
used for printing onto the recording medium of the present
invention, the solvent penetrates into the void-type ink-jet
medium before dots spread in a wet manner, after ink droplets
have come into contact with the medium surface, and thus the dot
diameter becomes small. Consequently, the image density easily
decreases, and particles become easier to notice in an image.
Thus, production of a high-quality image requires printing which
is higher in resolution than printing onto the recording medium
of the present invention, thereby leading to a decrease in printing
speed and an increase in ink consumption. Hence, it is desirable
to use the recording medium of the present invention.
[Recording Media]
Examples of the inorganic pigment contained in the
barrier layer in the present invention include magnesium
carbonate, talc, kaolin, illite, clay, calcium carbonate, calcium
sulfite, titanium white, magnesium carbonate and titanium
dioxide. Use of a pigment with a relatively high refractive index
among these pigments makes it possible to reduce the thickness
of the barrier layer. In terms of cost, use of calcium carbonate or
kaolin is preferable. These pigments may be used in
combination as long as the effects of the present invention are not
impaired; also, these pigments may be combined with other
pigments not included in the above-mentioned examples. Kaolin


is preferable in that it is superior in gloss developing property
and mates 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 properties, 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
2µm or less in diameter. The amount of the kaolin contained is
preferably 50 parts by mass or more. When the amount is less
than 50 parts by mass, sufficient effectiveness may not be
obtained with respect to glossiness.
Although the upper limit of the amount of the kaolin
contained is not particularly limited, it is further desirable in
terms of coating suitability that the amount be less than 90 parts
by mass, in view of the kaolin's fluidity, especially thickening
properties in the presence of high shearing force.
These pigments that have high refractive indices may be
used in combination with silica and/or organic pigments that
have low refractive indices. Examples of the organic pigments
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 with two or more.


The organic pigments are superior in. gloss developing property
and smaller in specific gravity than the inorganic pigments,
thereby making it possible to obtain coating layers which are
bulky, highly glossy and excellent in surface coating property.
When the amount of any of the organic pigments added is less
than 2 parts by mass, such effects cannot be obtained. When the
amount thereof is greater than 5 parts by mass, ink
strike-through is liable to arise, and also the cost will rise, which
is economically unfavorable. Examples of the forms of the
organic pigments include dense type, hollow type and doughnut
type; in light of a balance among the gloss developing property,
the surface coating property, and the fluidity of coating solution,
it is desirable that the organic pigments be in the range of 0.2µm
to 3.0µm in average particle diameter, and it is further desirable
to employ a hollow-type organic pigment having a void ratio of
40% or more.
The binder of the layer for preventing pigment penetration
(barrier layer) used in the present invention is not particularly
limited as long as it firmly adheres to the pigment and base paper
that constitute the barrier layer and it is made of an aqueous
resin, an emulsion or the like which does not cause blocking.
Examples of the aqueous binder include polyvinyl alcohol;
starches such as starch oxide, esterified starch, enzyme-modified
starch and cationated starch; cellulose derivatives such as casein,


soya bean proteins, carboxy methyl cellulose and hydroxyethyl
cellulose; and styrene-acrylic copolymer resins,
isobutylene-maleic anhydride copolymer resins, acrylic emulsions,
vinyl acetate emulsions, vinylidene chloride emulsions, polyester
emulsions, styrene-butadiene copolymer latex and
acrylonitrile'butadiene copolymer latex. Among these, use of
starches or styrene-butadiene copolymer latex is preferable in
terms of cost. The styrene-butadiene copolymer latex contains
styrene and butadiene as monomers, and these monomers may be
copolymerized with other monomers according to the necessity, or
the styrene-butadiene copolymer latex may be copolymer latex
commonly used for paper coating, in which the copolymer has
been modified by chemical reaction. Typical examples of the
other monomers include vinyl-based monomers such as acrylic
acid, methacrylic acid, altyl esters of (meth)acrylic acid,
acrylonitrile, maleic acid, fumaric acid and vinyl acetate. Also,
the styrene-butadiene copolymer latex may contain a
cross-linking 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. Each of these may be used
alone or in combination with two or more.
The amount of the aqueous binder added into the barrier
layer in the present invention is preferably 50% by mass to 70%


by mass, more preferably 55% by mass to 60% by mass, in relation
to the total coating layer solid content. When the amount is
smaller than the lower limit, the barrier layer is deficient in
adhesion, and thus there is concern that the strength of the ink
receiving layer might decrease, the internal bonding strength
might decrease, and detachment of particles might arise.
Further, other components may be added to the barrier
layer of the present invention 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
auxiliary agents contained in pigments for ordinary coated paper,
such as a dispersant, a thickener, a water retention agent, an
antifoaming agent and a water resistant additive; and additives
such as a pH adjuster, an antiseptic agent, an antioxidant and a
cationic organic compound.
A surfactant used in the barrier layer is not particularly
limited and may be suitably selected in accordance with the
intended use. For the surfactant, any one of an anionic
surfactant, a cationic surfactant, an amphoteric surfactant and a
nonionic surfactant may be used, with particular preference
being given to a nonionic surfactant.
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 with two or more.
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 50% or
less. The HLB (hydrophile-lipophile balance) of the nonionic
surfactant is preferably 4 to 15, more preferably 7 to 13.
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 of the cationic organic compound include
dimethylamine-epichlorhydrin polycondensates,
dimethylamine-ammonia-epichlorhydrin condensates,


poly(trimethylaminoethyl methacrylate-methylsulfate),
diallylamine hydrochloride-acrylamide copolymers,
poly (diallylamine bydrochloride-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),
polyCdiallyldimethylammonium chloride-sulfur dioxide),
poly(diallyldimethylammonium chloride-diallylamine
hydrochloride derivatives),
acrylaraide-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 with
two or more.
The support used in the present invention is produced by
mixing together chemical pulp, mechanical pulp, recycled pulp
and the like with an arbitrary ratio, and the raw materials to
which an internally added sizing agent, a yield improver, a paper


strength increasing agent and the like nave been added in
accordance with the necessity are made into paper using, for
example, a fourdrinier former, a gap-type twin-wire former, or a
hybrid former in which a posterior portion of a fourdrinier section
is composed of twin wires.
The pulp used in the support of the present invention may
contain a virgin chemical pulp (CP), for example one produced by
chemically treating a wood material such as leaf bleached kraft
pulp, needle bleached kraft pulp, leaf unbleached kraft pulp,
needle unbleached kraft pulp, leaf bleached sulfite pulp, needle
bleached sulfite pulp, leaf unbleached sulfite pulp or needle
unbleached sulfite pulp, or other fiber raw material; and a virgin
mechanical pulp (MP), for example one produced by mechanically
treating a wood material such as ground, pulp, chemiground pulp,
chemimechanical pulp or semi-chemical pulp, or other fiber raw
materiaL
Also, recycled pulp may be used as well, and 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 chemical pulp paper and high-yield
pulp-containing paper. Each of these may be used alone or in
combination with two or more.
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 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.
(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 a filler able to be used in the support of the present
invention, use of calcium carbonate is effective, and the following
materials may be additionally used: inorganic fillers exemplified
by silicates such as kaolin, fired clay, pyrophyllite, sericite and
talc; and organic pigments such as satin white, barium sulfate,
calcium sulfate, zinc sulfide, plastic pigments and urea resins.
The internally added sizing agent used in the support of
the present invention is not particularly limited and may be
suitably selected from known internally added sizing agents used
for ink-jet recording paper. Suitable examples of the internally
added sizing agent include rosin emulsion sizing agents.
Examples of the 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 the alkyl ketene dimers can be


added in small amounts due to their strong sizing effects, they
may be unfavorable in terras of paper conveyance at the time of
ink-jet recording because the friction coefficient of the recording
paper (medium) surface decreases and thus the surface easily
becomes slippery.
The amount of the internally added sizing agent used is
preferably 0.1 parts by mass to 0.7 parts by mass per 100 parts by
mass of bone-dry pulp; however, the amount is not limited
thereto.
For the internally added filler in the support, a pigment
which is conventionally known 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 with two or
more.



The method for providing the barrier layer over the
support of the present invention by coating is not particularly
limited. For instance, it is possible to utilize a method of
directly coating a support with a barrier layer, a method in which
a barrier layer that has been applied onto another base material
is transferred onto original paper, or a method of applying a
barrier layer in the form of a mist, using a spray or the like.
Examples of the method of directly coating a support with a
barrier layer include film transfer methods such as roll coater
method, air knife coater method, gate roll coater method, size
pressing, Symsizer method, and rod metalling size press coater
method; and blade coater methods such as fountain method and
roll application.
The barrier layer can be dried using a hot-air drying oven
or a thermal drum, for instance. Further, the barrier layer may
be subjected to a surface-finishing process using a calendering
device (supercalender, soft calender, gloss calender, etc.) so as to
flatten its surface or increase the strength of its surface.
The barrier layer of the present invention can be provided
by coating, as described above; in addition, as a result of carrying
out an earnest study, the present inventors have found that the
barrier layer of the present invention can also be produced by
polishing the surface of existing coated paper for printing. It is
inferred that this is possible because the thickness of the coat


layer is reduced by the polishing to the thickness shown in the
present invention, a resin layer present on the outermost surface
is shaved, which makes pores appear, and thus a layer
functioning as a barrier layer is obtained.
The existing coated paper for printing denotes coated
paper used for commercial printing exemplified by offset printing,
gravure printing, etc., and examples thereof include art paper
(A0, A1), A2 coated paper, A3 coated paper, B2 coated paper, light
coated paper and finely coated paper.
The following shows examples of the coated paper as
specific products. Examples thereof as art paper include OK
KINFUJI N, OK KINFUJI-R40N, SA KINFUJI N, SATIN
KINFUJI N, SATIN KINFUJI-R40N, ULTRA-SATIN KINFUJI N,
ULTRA-OK KINFUJI N and KINFUJI SINGLE SIDE (produced
by Oji paper Co., Ltd.); NPi SPECIAL ART, NPi SUPER ART, NPi
SUPER DULL and NPi DULL ART (produced by Nippon Paper
Group, Inc.); UTRILLO SUPER ART, UTRILLO SUPER DULL
and UTRILLO PREMIUM (produced by Daio Paper Corporation);
HIGH-GRADE ART A, SPECIAL MITSUBISHI ART, SUPER MAT
ART A and HIGH-GRADE DULL ART A (produced by Mitsubishi
Paper Mills Limited); and RAICHO SUPER ART N, RAICHO
SUPER ART MN, RAICHO SPECIAL ART and RAICHO DULL
ART N (produced by Chuetsu Pulp & Paper Co., Ltd.).
Examples thereof as A2 coated paper include OK TOP


COAT + (PLUS), OK TOP COAT S, OK CASABLANCA, OK
CASABLANCA V, OK TRINITY, OK TRINITY NAVI, NEW AGE,
NEW AGE W, OK TOP COAT MATT N, OK ROYAL COAT, OK TOP
COAT DULL, Z COAT, OK KASAHIME, OK KASAO, OK KASAO
SATIN, OK TOP COAT +, OK NON-WRINKLE, OK COAT V, OK
COAT N GREEN 100, OK MATT COAT GREEN 100, NEW AGE
GREEN 100 and Z COAT GREEN 100 (produced by Oji paper Co.,
Ltd.); AURORA COAT, SHIRAOI MATT, IMPERIAL MATT,
SILVER DIAMOND, RECYCLE COAT 100 and CYCLE MATT 100
(produced by Nippon Paper Group, Inc.); µ COAT, µ WHITE, µ-
MATT and WHITE µ MATT (produced by Hokuetsu Paper Mills,
Ltd.); RAICHO COAT N, REGINA RAICHO COAT 100, RAICHO
MATT COAT N and REGINA RAICHO MATT 100 (produced by
Chuetsu Pulp & Paper Co., Ltd.); and PEARL COAT, WHITE
PEARL COAT N, NEW V MATT, WHITE NEW V MATT, PEARL
COAT REW, WHITE PEARL COAT NREW, NEW V MATT REW
and WHITE NEW V MATT REW (produced by Mitsubishi Paper
Mills Limited).
Examples thereof as A3 coated (light coated) paper include
OK COAT L, ROYAL COAT L, OK COAT LR, OK WHITE L, OK
ROYAL COAT LR, OK COAT L GREEN 100 and OK MATT COAT
L GREEN 100 (produced by Oji paper Co., Ltd.); EASTER DX,
RECYCLE COAT L100, AURORA L, RECYCLE MATT L100 and
ENERGY WHITE (produced by Nippon Paper Group, Inc.);


UTRILLO COAT L and MATISSE COAT (produced by Daio Paper
Corporation); HIGH-ALPHA, ALPHA MATT, (N) KINMARI L and
KINMARI HiL (produced by Hokuetsu Paper Mills, Ltd.); N
PEARL COAT L, N PEARL COAT LREW and SWING MATT REW
(produced by Mitsubishi Paper Mills Limited); and SUPER
EMINE, EMINE and SHATON (produced by Chuetsu Pulp &
Paper Co., Ltd.).
Examples thereof as B2 coated (medium-quality coated)
paper include OK MEDIUM-QUALITY COAT, '(F) MCOP, OK
ASTRO GLOSS, OK ASTRO DULL and OK ASTRO MATT
(produced by Oji paper Co., Ltd.); and KING O (produced by
Nippon Paper Group, Inc.).
Examples thereof as finely coated paper include OK
ROYAL LIGHT S GREEN 100, OK EVER LIGHT COAT, OK EVER
LIGHT R, OK EVER GREEN, CLEAN HIT MG, OK FINE
COATING SUPER ECO G, ECO GREEN DULL, OK FINE
COATING MATT ECO G100, OK STAR LIGHT COAT, OK SOFT .
ROYAL, OK BRIGHT, CLEAN HIT G, YAMAYURI BRIGHT,
YAMAYURI BRIGHT G, OK AQUA-LIGHT COAT, OK ROYAL
LIGHT S GREEN 100, OK BRIGHT (Rough And Glossy), SNOW
MATT, SNOW MATT DX, OK KASAHIME and OK KASAYURI
(produced by Oji paper Co., Ltd.); PYRENE DX, PEGASUS
HYPER 8, AURORA S, ANDES DX, SUPER ANDES DX, SPACE
DX, SEINE DX, SPECIAL GRAVURE DX, PEGASUS, SILVER


PEGASUS, PEGASUS HARMONY, GREENLAND DX100, SUPER
GREENLAND DX100, ENERGY SOFT, ENERGY
LIGHT and EE HENRY (produced by Nippon Paper Group, Inc.);
KANT EXCEL, EXCEL SUPER B, EXCEL SUPER C, KANT
EXCEL BARU, UTRILLO EXCEL, HEINE EXCEL and DANTE
EXCEL (produced by Daio Paper Corporation); COSMO ACE
(produced by Nippon Daishowa Paperboard Co,. Ltd.);
SEMI-UPPER L, HIGH BETA, HIGH GAMMA, SHIROMARI L,
HUMMING, WHITE HUMMING, SEMI-UPPER HIL and
SHIROMARI HIL (produced by Hokuetsu Paper Mills, Ltd.);
RUBY LIGHT HREW, PEARL SOFT and RUBY LIGHT H
(produced by Mitsubishi Paper Mills Limited); Shaton, Ariso and
Smash (produced by Chuetsu Pulp & Paper Co., Ltd.); and Star
Cherry and Cherry Super (produced by Marusumi Paper Co.,
Ltd.).
As seen in many documents, a coat layer of ordinary
commercial printing paper is formulated so as to contain a binder
(resin, emulsion, starch, etc.) by approximately 10 parts by mass
to 15 parts by mass per 100 parts by mass of an inorganic pigment
(kaolin, calcium carbonate, etc.). Here, when the manner in
which the pigment is present in the coat layer, and further, the
concentration gradient of the pigment in the coat layer are taken
into consideration, the following can be regarded as possible: (1)
formation of a clear layer or the like on the outermost surface of a


coating film, as often seen in the case of paint, etc.; (2)
penetration of binder components into original paper, which, may
cause the tipper and lower layers to have asymmetrical
concentration distributions. As to (1), it has been found that
matters related to (1) are scarcely discussed in documents
(documents concerning the glossiness, etc. of coated paper) in the
relevant field. It is inferred that since the ratio of resin to other
components in the coat layer is lower than the ratio of resin to
other components in ordinary paint or the like, and the amount of
the resin in the coat layer is not large enough for the resin to be
deposited on the surface, anything like a clear layer does not
easily form.
In meetings aimed at exchanging technical opinions with
experts engaged in producing commercial coated paper, many of
them are found to have a technological concept that a binder
should have a function of providing strength to such an extent
that a layer can be prevented from peeling off at the time of
printing or particles can be prevented from detaching at the time
of cutting; also, perhaps the production of coated paper is liable
to become troublesome, as the amount of resin increases;
accordingly, in the case of this type of paper, some hope to add a
binder as little as possible.
As to (2), it is actually said that as the resin in the coating
solution penetrates into the original paper, there arises a


phenomenon in which the proportion of the resin in a coating
layer becomes lower (than the proportion of the resin in the
coating solution) or a layer is formed at the interface between the
coating layer and the original paper; however, an example of
creation of a gradient in the layer itself has not yet been
confirmed (even in documents). Nevertheless, formation of a
resin-rich layer at the interface between the coating layer and the
original paper is possible, in which case lower parts of the layer
have higher resin concentrations.
Examples of the method for polishing the outermost layer
of the coated paper include, but are not limited to, a method of
polishing with the use of sandpaper or wrapping paper, a method
of polishing with the use of a wire brush, a method of polishing
with the use of a polishing roller or an endless polishing belt, and
a method of polishing with the use of a sandblast.
In producing the coated paper, the polishing may be
carried out by arbitrarily providing a polishing process
immediately after drying, before or after calendering, or in a
process subsequent to coating, such as a slit process or packing
process; alternatively, a user may carry out the polishing before
printing, using a polishing device. Also, the polishing device
may be installed in a printer so as to perform polishing each time
printing is conducted.
As to the polishing, the whole surface of paper may be


polished, or only an area to be subjected to ink-jet printing may
be selectively polished.
For instance, the following paper usage is possible- the
above-mentioned ordinary printing paper is subjected to offset
printing or gravure printing in advance, then only an area which
requires ink-jet printing is polished, and the area is printed with
images, letters/characters, etc.
According to this method, hybrid printing, which has
conventionally been performed using paper suitahle for both
ink-jet printing and ordinary printing, can also be performed
using the above-mentioned ordinary printing paper, and thus it
becomes possible for ordinary printing and ink-jet printing to
employ paper in common. Also, this method enables printing of
an address, etc. by ink-jet printing, which has been deemed
difficult to achieve in ordinary printing.
Additionally, the polishing device may be installed in a
unit of the printer, or may be independently prepared as a
separate unit.
Specially made coated paper can be substituted for the
medium of the present invention, as long as it satisfies the
requirements of the present invention. In particular, coated
paper in which the air permeability of a coat layer itself is high
can be used. Examples of the coated paper in which the air
permeability of a coat layer is high include some coated paper for


electronic photographs, and coated paper for gravure printing.
Specific examples thereof include POD GLOSS COAT (produced
by Oji paper Co., Ltd.), FL GRAVURE (produced by Nippon Paper
Group, Inc.), and ACE (produced by Nippon Paper Group, Inc.).
These products include coat layers having large numbers of pores,
and so any of these products can be used as the medium including
the barrier layer of the present invention.
The ink included in the ink media set of the present
invention can be suitably used for printers equipped with ink-jet
heads of any type, including the piezo type in which ink droplets
are ejected by deforming a diaphragm that forms a wall surface of
an ink flow path, with the use of a piezoelectric element as a
pressure generating unit that pressurizes ink in the ink flow path,
and thusly changing the volume of the ink flow path (refer to
JP-A No. 02-51734); the thermal type in which bubbles are
generated by heating ink in an ink flow path with the use of an
exothermic resistive element (refer to JP-ANo. 61-59911); and
the electrostatic type in which ink droplets are ejected by placing
a diaphragm and an electrode, which form a wall surface of an ink
flow path, to face each other, then deforming the diaphragm by
electrostatic force generated between the diaphragm and the
electrode, and thusly changing the volume of the ink flow path
(refer to JP-A No. 06-71882).
As described above, the recording medium in the ink media


set is used in combination with the ink in the ink media set. The
combination of the recording medium and the ink can be suitably
used in various fields, notably in image recording apparatuses
(printers) based upon ink-jet recording; for instance, the
combination of the recording medium and the ink can be
particularly suitably used for an ink cartridge, ink recorded
matter, an ink-jet recording apparatus and an ink-jet recording
method of the present invention described below.
[Ink Cartridge]
An ink cartridge of the present invention includes a
container to house the ink included in the ink media set of the
present invention, and further includes other members, etc.
suitably selected in accordance with the necessity.
The container is not particularly limited, and the shape,
structure, size, material and the like thereof may be suitably
selected in accordance with the intended use. Suitable examples
thereof include a container having an ink bag or the like formed
of an aluminum laminated film, resin film, etc.
Next, the ink cartridge will be explained with reference to
FIGS. 1 and 2. Here, FIG. 1 is a diagram showing one example
of the ink cartridge of the present invention, and FIG. 2 is a
diagram exemplarily showing the ink cartridge of FIG. 1 with the
inclusion of a case (outer covering).
In respect of an ink cartridge (200), as shown in FIG. 1, the


ink of the present invention is supplied from, an ink inlet (242)
into an ink bag (241), and the ink inlet (242) is closed by means of
fusion bonding after air is discharged. When the ink cartridge is
used, an ink ejection outlet (243) made of a rubber material is
pricked with a needle of an apparatus main body, and the ink is
thus supplied to the apparatus.
The ink bag (241) is formed of an air-impermeable packing
material such as an aluminum laminated film. As shown in FIG.
2, this ink bag (241) is normally housed in a plastic cartridge case
(244) and detachably mounted on a variety of ink-jet recording
apparatuses.
The ink cartridge of the present invention houses the ink
included in the ink media set of the present invention and can be
detachably mounted on a variety of ink-jet recording apparatuses.
It is particularly desirable that the ink cartridge be detachably
mounted on an ink-jet recording apparatus of the present
invention described below.
[Ink-jet Recording Method and Ink-jet Recording Apparatus]
An ink-jet recording apparatus of the present invention
includes at least an ink jetting unit, and further includes other
units suitably selected in accordance with the necessity, such as a
stimulus generating unit and a controlling unit.
An ink-jet 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, such as a
stimulus generating step and a controlling step.
The ink-jet recording method of the present invention can
be suitably performed by the ink-jet recording apparatus of the
present invention, and the ink jetting step can be suitably
performed by the ink jetting unit. Also, the other steps can be
suitably performed by the other units.
The ink jetting step is a step of jetting the ink included in
the ink media set of the present invention so as to record an
image on the recording medium included in the ink media set, by
applying a stimulus to the ink.
The ink jetting unit is a unit configured to jet the ink
included in the ink media set of the present invention so as to
record an image on the recording medium included in the ink
media set, by applying a stimulus to the ink. The ink jetting
unit is not particularly limited, and examples thereof include
nozzles for ejecting ink. .
In the present invention, at least part of a liquid chamber,
a fluid resistance unit, a diaphragm and a nozzle member of an
ink-jet head is preferably formed of a material containing at least
either silicone or nickel.
Also, the diameter of the ink-jet nozzle is preferably 30µm
or less, more preferably 1µm to 20µm.
Additionally, sub-tanks for supplying ink onto the ink-jet


head are preferably provided such, that the sub-tanks are
replenished with ink from the ink cartridge via a supply tube.
Further, in the ink-jet recording method of the present
invention, the maximum amount of the ink attached onto the
recording medium is preferably 8g/m2 to 20g/m2 at a resolution of
300dpi or higher.
The stimulus can, for example, be generated by the
stimulus generating unit, and the stimulus is not particularly
limited and may be suitably selected in accordance with the
intended use. Examples thereof include heat, pressure,
vibration and light. Each of these may be used alone or in
combination with two or more. Among these, heat and pressure
are suitable.
Examples of the stimulus generating unit include heaters,
pressurizers, piezoelectric elements, vibration generators,
ultrasonic oscillators and lights. Specific examples thereof
include 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.
The manner in which the ink included in the ink media set


jets is not particularly limited and varies according to the type or
the like of the stimulus. In the case where the stimulus is "heat",
there is, for example, a method in which thermal energy
corresponding to a recording signal is given to the ink in a
recording head, using a thermal head or the like, hubbies are
generated in the ink by the thermal energy, and the ink is ejected
as droplets from nozzle holes of the recording head by the
pressure of the bubbles. Meanwhile, in the case where the
stimulus is "pressure", there is, for example, a method in which
by applying voltage to a piezoelectric element bonded to a site
called a pressure chamber that lies in an ink flow path in a
recording head, the piezoelectric element bends, the volume of
the pressure chamber decreases, and thus the ink is ejected as
droplets from nozzle holes of the recording head.
It is desirable that the ink droplets jetted be, for example,
lpl to 40pl in size, 5m/s to 20m/s in ejection velocity, 1kHz or
greater in drive frequency and 300dpi or greater in resolution.
The controlling unit is not particularly limited and may be
suitably selected in accordance with the intended use, as long as
it can control operations of the aforementioned units. Examples
thereof include apparatuses such as a sequencer and a computer.
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. The ink-jet recording apparatus in FIG. 3 includes an
apparatus main body (101), a paper feed tray (102) for feeding
paper that is loaded thereon into the apparatus main body (101),
a paper discharge tray (103) for storing paper which has been
loaded into the apparatus main body (101) and on which images
have been recorded (formed), and an ink cartridge loading section
(104). An operation unit (105) composed of operation keys, a
display and the like is placed on the upper surface of the ink
cartridge loading section (104). The ink cartridge loading
section (104) has a front cover (115) capable of opening and
closing to attach and detach an ink cartridge (200).
In FIGS. 3 and 4, (111) denotes an upper cover of the
ink-jet recording apparatus, and (112) denotes a front surface of
the ink-jet recording apparatus.
In the apparatus main body (101), as shown in FIGS. 4 and
5, a carriage (133) is freely slidably held in the main scanning
direction by a guide rod (131), which is a guide member laterally
passed between left and right side plates (not shown), and a stay
(132)." and the carriage (133) is moved for scanning in the
direction indicated by the arrow A in FIG. 5 by a main scanning
motor (not shown). The belt moves in the direction indicated by
the arrow B in FIG. 5 to convey paper.
A recording head (134) composed of four ink-jet recording
heads which eject ink droplets of yellow (Y), cyan (C), magenta


(M) and black (Bk) is installed in the carriage (133) 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 (134), it is possible to use, for example, a head
provided with any of the following actuators as a
energy-generating unit for ejecting 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 (133) incorporates sub-tanks (135) of
each color for supplying inks of each color to the recording head
(134). Each sub-tank (135) is supplied and replenished with the
ink included in the ink media set of the present invention from
the ink cartridge (200) of the present invention loaded into the
ink cartridge loading section (104), via an ink supply tube (not
shown).
Meanwhile, as a paper feed unit for feeding sheets of paper
(142) loaded on a paper loading section (pressure plate) (141) of
the paper feed tray (102), there are provided a half-moon roller


(paper feed roller (143)) which, feeds the sheets of paper (142) one
by one from the paper loading section (141), and a separation pad
(144) which faces the paper feed roller (143) and is formed of a
material with a large friction coefficient. This separation pad
(144) is biased toward the paper feed roller (143) side.
As a conveyance unit for conveying the paper (142), which
has been fed from this paper feed unit, under the recording head
(134), there are provided a conveyance belt (151) for conveying
the paper (142) by means of electrostatic adsorption; a counter
roller (152) for conveying the paper (142), which is sent from the
paper feed unit via a guide (145), such that the paper (142) is
sandwiched between the counter roller (152) and the conveyance
belt (151); a conveyance guide (153) for making the paper (142),
which is sent upward in the substantially vertical direction,
change its direction by approximately 90° and thusly correspond
with the conveyance belt (151); and an end pressurizing roller
(155) biased toward the conveyance belt (151) side by a pressing
member (154). Also, there is provided a charging roller (156) as
a charging unit for charging the surface of the conveyance belt
(151).
The conveyance belt (151) is an endless belt and is capable
of moving in circles in the belt conveyance direction, passed
between a conveyance roller (157) and a tension roller (158).
The conveyance belt (151) has, for example, a surface layer


serving as a paper adsorbing surface, that is formed of a resinous
material such, as an ethylene-tetrafluoroethylene copolymer
(ETFE) having a thickness of approximately 40µm for which
resistance control has not been conducted, and a back layer
(intermediate resistance layer, ground layer) that is formed of the
same material as this surface layer, for which resistance control
has been conducted using carbon. On the back of the conveyance
belt (151), a guide member (161) is placed correspondingly to a
region where printing is carried out by the recording head (134).
Additionally, as a paper discharge unit for discharging the paper
(142) on which images or the like have been recorded by the
recording head (134), there are provided a separation pawl (171)
for separating the paper (142) from the conveyance belt (151), a
paper discharge roller (172) and a paper discharge small roller
(173), with the paper discharge tray (103) being placed below the
paper discharge roller (172).
A double-sided paper feed unit.(l8l) is mounted on a rear
surface portion of the apparatus main body (101) in a freely
detachable manner. The double-sided paper feed unit (181)
takes in the paper (142) returned by rotation of the conveyance
belt (151) in the opposite direction and reverses it, then refeeds it
between the counter roller (152) and the conveyance belt (l5l).
Additionally, a manual paper feed unit (182) is provided on an
upper surface of the double-sided paper feed unit (181).


In this ink-jet recording apparatus, the sheets of paper
(142) are fed one by one from the paper feed unit, and the paper
(142) fed upward in the substantially vertical direction is guided
by the guide (145) and conveyed between the conveyance belt
(151) and the counter roller (152). Further, the conveyance
direction of the paper (142) is changed by approximately 90°, as
an end of the paper (142) is guided by the conveyance guide (153)
and pressed onto the conveyance belt (151) by the end
pressurizing roller (155).
On this occasion, the conveyance belt (151) is charged by
the charging roller (156), and the paper (142) is electrostatically
adsorbed onto the conveyance belt (151) and thusly conveyed.
Here, by driving the recording head (134) according to an image
signal while moving the carriage (133), ink droplets are ejected
onto the paper (142) having stopped so as to carry out recording
for one line, and after the paper (142) is conveyed by a
predetermined distance, recording for the next line is carried out.
On receipt of a recording completion signal or such a signal as
indicates that the rear end of the paper (142) has reached the
recording region, recording operation is finished, and the paper
(142) is discharged onto the paper discharge tray (103).
Once the amount of ink remaining in the sub-tanks (135)
has been detected as too small, a required amount of ink is
supplied from the ink cartridge (200) into the sub-tanks (135).


As to this ink-jet recording apparatus, when ink in the ink
cartridge (200) of the present invention has been used up, it is
possible to replace only an ink bag inside the ink cartridge (200)
by dismantling the housing of the ink cartridge (200). Also, even
when the ink cartridge (200) is longitudinally placed and employs
a front-loading structure, it is possible to supply ink stably.
Therefore, even when the apparatus main body (101) is installed
with little space over it, for example when the apparatus main
body (101) is stored in a rack or when an object is placed over the
apparatus main body (101), it is possible to replace the ink
cartridge (200) with ease.
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.
Also, the ink-jet recording apparatus and the ink-jet
recording method of the present invention can be applied to a
variety of types of recording based upon ink-jet recording systems.
For example, they can be particularly suitably applied to ink-jet
recording printers, facsimile apparatuses, copiers,
printer/fax/copier complex machines, and so forth.


The following explains an ink-jet head to which the
present invention is applied.
FIG. 6 is an enlarged view showing elements of an ink-jet
head to which the present invention has been applied, and FIG. 7
is an enlarged cross-sectional view showing main parts of the
ink-jet head with respect to the channel-to-channel direction.
This ink-jet head is composed of a frame (10) provided with
an ink supply port (not shown) (which supplies ink in the
direction from the surface toward the back in FIG. 6 (toward the
back surface of paper)) and an indentation serving as a common
liquid chamber (12); a flow path plate (20) including a fluid
resistance section (21), an indentation serving as a pressurized
liquid chamber (22), and a communicating port (23)
communicated with a nozzle (31); a nozzle plate (30) forming the
nozzle (31); a diaphragm (60) provided with a diaphragm
protrusion (61), a diaphragm part (62) and an ink flow-in port
(63); a laminated piezoelectric element (50) joined to the
diaphragm (60) with an adhesive layer (70) placed in between;
and a base (40) on which the laminated piezoelectric element (50)
is fixed. The base (40) is made of a barium titanate-based
ceramic and joined to the laminated piezoelectric element (50)
that is arranged in two rows.
In the laminated piezoelectric element (50), piezoelectric
layers (51), which are formed of lead zirconate titanate (PZT) and


each, one of which is 10µm to 50µm in thickness, and internal
electrode layers (52), which are formed of silver-palladium (AgPd)
and each one of which is several micrometers in thickness, are
alternately deposited on top of one another. The internal
electrode layers (52) are connected to external electrodes (53), at
their ends on both sides.
The laminated piezoelectric element (50) is formed into the
shape of comb teeth by half-cut dicing, in which drive parts (56)
and support parts (non-drive parts) (57) are alternately disposed
(FIG. 7).
The length of the outer end of one of the two external
electrodes (53) (which is contiguous to the ends of the internal
electrode layers (52) on one side in the direction of the surface or
the back in FIG. 6 (the back surface of paper)) is limited by
cutting or the like so as to be divided by half-cut dicing, and
divided pieces serve as individual electrodes (54). The other of
the two external electrodes (53) is not divided by dicing but
electrically continuous, serving as a common electrode (55).
An FPC (80) is welded to the individual electrodes (54) of
the drive parts. With an electrode layer provided at an end of
the laminated piezoelectric element, the common electrode (55) is
joined to a Gnd electrode of the FPC (80) in a twisted manner.
On the FPC (80), a driver IC (not shown) is mounted, which
controls application of drive voltage to the drive parts (56).


The diaphragm (60) is equipped with, the diaphragm part
(62) formed as a thin film," the island-like convex portion (island
part) (61) which is formed at the center of this diaphragm part
(62) and joined to the drive parts (56) of the laminated
piezoelectric element (50); a thick film portion including a beam
joined to the support parts (not shown); and an opening serving
as the ink flow-in port (63), formed by combining two Ni-plated
films produced by electroforming. The diaphragm portion has a
thickness of 3p.m. and a width of 35µm (with respect to one side).
By patterning the adhesive layer (70) including a gap
material, the island-like diaphragm protrusion (6l) of the
diaphragm (60) is bonded to the drive parts (56) of the laminated
piezoelectric element (50), and the diaphragm (60) is bonded to
the frame (10).
As to the flow path plate (20), the following members are
patterned by etching with the use of a silicon single-crystal
substrate: the fluid resistance section (21); the indentation
serving as the pressurized liquid chamber (22); and a
through-hole serving as the communicating port (23), placed in a
position corresponding to the nozzle (31).
The portions that remain unetched serve as partitions (24)
of the pressurized liquid chamber (22). Additionally, this head
is provided with a portion where the etching width is small to
serve as the fluid resistance section (21).


A nozzle plate (30) is formed of a metal material, for
example an Ni-plated film produced by electroforming, and a
large number of nozzles (31), which are minute ejection outlets
for jetting ink droplets, are formed therein. The internal shape
(inner shape) of each of these nozzles (31) is similar to the shape
of a horn (which may otherwise be a substantially columnar
shape or a substantially conical and trapezoidal shape). Also,
the diameter of each of these nozzles (31) is approximately 20urn
to 35µm as a diameter on the side where ink droplets exit.
Additionally, the nozzle pitch in each row is 150dpi.
An ink ejection surface (on the nozzle surface side) of the
nozzle plate (30) is provided with a water-repellent layer (not
shown) which has been subjected to water-repellent surface
treatment. High image quality is obtained through stabilization
of the droplet shape and jetting properties of ink by providing a
water-repellent film selected in accordance with the ink
properties, which is produced by PTFE-Ni eutectoid plating,
electrodeposition of a fluorine resin, vapor deposition coating of
an evaporable fluorine resin (such as a fluorinated pitch), baking
of a silicone resin and a fluorine resin after application of solvent,
etc. For instance, as to the fluorine resin among these, although
a variety of materials are known as fluorine resins, superior
water repellency can be obtained by subjecting a modified
perfluoropolyoxetane (product name: OPTOOL DSX, produced by


Daikin Industries, Ltd.) to vapor deposition so as to have a
thickness of 30A to 100A.
The frame (10) including the ink supply port and the
indentation serving as the common liquid chamber (12) is
produced by molding a resin.
As to the ink-jet head with such a structure, by applying a
drive waveform (a pulse voltage of 10V to 50V) to the drive parts
(56) correspondingly to a recording signal, displacement of the
lamination direction is generated in the drive parts (56), there is
an increase in pressure as the pressurized liquid chamber (22) is
pressurized, and thus ink droplets are ejected from the nozzle
(31) formed in the nozzle plate (30).
Thereafter, once ejection of ink droplets is over, the ink
pressure in the pressurized liquid chamber (22) lowers, and
negative pressure is generated in the pressurized liquid chamber
(22) due to inertia of the flow of ink and a drive pulse discharge
process, which is followed by an ink supply step. On this
occasion, the ink supplied from an ink tank flows into the
common liquid chamber (12), passes from the common liquid
chamber (12) through the fluid resistance section (21) via the ink
flowin port (63) and then is supplied into the pressurized liquid
chamber (22).
The fluid resistance section (21) is effective in reducing
residual pressure vibrations after ink ejection; conversely, it


serves as a resistance to refilling effected by surface tension. By
suitably selecting the fluid resistance section, it becomes possible
to balance reduction in residual pressure and refill time and to
shorten the time spent in shifting to an ink droplet ejecting
operation that follows (the driving cycle).
In FIGS. 6 and 7, 90 denotes an ink-repellent layer.
Examples
The following explains Examples of the present invention;
however, it should be noted that the present invention is not
confined to these Examples in any way.
Preparation Example 1 (Surface-treated carbon black pigment
dispersion solution)
Into 3,000mL of 2.5N sodium sulfate solution, 90g of
carbon black having a CTAB specific surface area of 150ra2/g and
a DBP oil absorption of 100mL/100g was added, then the mixture
was stirred at a temperature of 60°C and a rotational speed of
300rpm and subjected to reaction for 10hr, and the carbon black
was thus oxidized. This reaction solution was filtered, then the
carbon black which had been filtered out was neutralized with a
sodium hydroxide solution and subjected to ultrafiltration.
The carbon black obtained was washed with water and
dried, then dispersed into purified water such that its amount
was 20% by mass.


Preparation Example 2 (Surface-treated yellow pigment
dispersion solution)
As a yellow pigment, a pigment was produced by
plasma-treating C. I. Pigment Yellow 128 at a low temperature
and introducing a carboxylic acid group. This pigment was
dispersed into ion-exchange water, then the solution was
demineralized and condensed using an ultrafiltration membrane,
and a yellow pigment dispersion solution having a pigment
concentration of 15% was thus obtained.
Preparation Example 3 (Preparation of surface-treated
magenta pigment)
A surface-modified magenta pigment was prepared in
accordance with the procedure of Preparation Example 2, using
Pigment Red 122 instead of C. I. Pigment Yellow 128. As in the
above-mentioned example, a surface-modified coloring pigment
obtained was easily dispersed in an aqueous medium when
stirred, then the solution was demineralized and condensed using
an ultrafiltration membrane, and a magenta pigment dispersion
solution having a pigment concentration of 15% was thus
obtained.
Preparation Example 4 (Preparation of surface-treated
cyan pigment)
A surface-modified cyan pigment was prepared in
accordance with the procedure of Preparation Example 2, using C.


I. Pigment Cyan 15:3 instead of C. I. Pigment Yellow 128. As in
the above-mentioned example, a surface-modified coloring
pigment obtained was easily dispersed in an aqueous medium
when stirred, then the solution was demineralized and condensed
using an ultrafiltration membrane, and a cyan pigment
dispersion solution having a pigment concentration of 15% was
thus obtained.
Synthesis Example 1 (Preparation of polymer dispersion
solution)
The atmosphere, inside a 1L flask equipped with a
mechanical stirrer, a thermometer, a nitrogen gas introducing
pipe, a reflux condenser and a dripping funnel was adequately
replaced by nitrogen gas, then 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.) and 0.4g of mercaptoethanol were
placed, and the temperature was raised to 65°C. Next, a mixed
solution of 100.8g of styrene, 25.2g of acrylic acid, 108.0g of
lauryl methacrylate, 36.0g of polyethylene glycol methacrylate,
60-0g of hydroxyethyl methacrylate, 36.0g of a styrene macromer
(product name: AS-6 produced by Toagosei Co., Ltd.), 3.6g of
mercaptoethanol, 2.4g of azobisdimethylvaleronitrile and 18g of
methyl ethyl ketone was poured dropwise into the flask in 2.5hr.
After the dropping of the mixed solution.had finished, a mixed


solution of 0.8g of azobisdimethylvaleroaitrile and 18g of methyl
ethyl ketone was applied dropwise into the flask in 0.5hr. The
ingredients were aged at 65CC for 1hr, then 0.8g of
azobismethylvaleronitrile was added, and further, the
ingredients were aged for 1hr. After reaction had finished, 364g
of methyl ethyl ketone was added into the flask, and 800g of a
polymer solution having a concentration of 50% by mass was thus
obtained.
Preparation Example 5 (Preparation of fine polymer
particle dispersion containing phthalocyanine pigment)
After sufficiently stirring 28g of the polymer solution
produced in Synthesis Example 1, 26g of a phthalocyanine
pigment, 13.6g of lmol/L potassium hydroxide solution, 20g of
methyl ethyl ketone and 30g of ion-exchange water, the
ingredients were kneaded using a three-roll mill. The paste
obtained was put into 200g of ion-exchange water, and the
solution was sufficiently stirred; thereafter, the methyl ethyl
ketone and the water were removed by distillation using an
evaporator, and a cyan fine polymer particle dispersion was thus
obtained.
Preparation Example 6 (Preparation of fine polymer
particle dispersion containing dimethyl quinacridone pigment)
A magenta fine polymer particle dispersion was obtained
in a manner similar to Preparation Example 5, except that the


phthalocyanine pigment was changed to Pigment Red 122.
Preparation Example 7 (Preparation of fine polymer
particle dispersion containing monoazo yellow pigment)
A yellow fine polymer particle dispersion was obtained in a
manner similar to Preparation Example 5, except that the
phthalocyanine pigment was changed to Pigment Yellow 74.
Preparation Example 8 (Preparation of fine polymer
particle dispersion containing carbon black pigment)
A black fine polymer particle dispersion was obtained in a
manner similar to Preparation Example 5, except that the
phthalocyanine pigment was changed to carbon black.
Preparation Example 9 (Preparation of phthalocyanine
pigment dispersion)
A mixture was prepared by mixing 150g of C. I. Pigment
Cyan 15:3, 110g of a polyoxyethylene β-naphthyl ether as a
pigment dispersant represented by Structural Formula (2) shown
below (R: alkyl group, m=4, n=40), 2g of Pionin A-51-B (produced
by Takemoto Oil & Fat Co., Ltd.) and 738g of distilled water, then
this mixture was predispersed and subsequently dispersed in a
circulated manner for 20hr using a disc-type bead mill (Model
KDL, manufactured by Shiumaru Enterprises Corporation;
media: 0.3mm zirconia balls), and a phthalocyanine pigment
dispersion was thus obtained.



Structural Formula (2)
(In Structural Formula (2), R denotes an alkyl group having 1 to
20 carbon atoms, m denotes an integer of 0 to 7, and n denotes an
integer of 20 to 200.)
Preparation Example 10 (Preparation of dimethyl
quinacridone pigment dispersion)
A dimethyl quinacridone pigment dispersion was obtained
in a manner similar to Preparation Example 9, except that the C.
I. Pigment Cyan 15:3 was changed to C. I. Pigment Red 122.
Preparation Example 11 (Preparation of monoazo yellow
pigment dispersion)
A monoazo yellow pigment dispersion was obtained in a
manner similar to Preparation Example 9, except that the C. I.
Pigment Cyan 15:3 was changed to C. I. Pigment Yellow 74.
The following shows a synthesis example of an
acrylic-silicone resin emulsion among components able to be
contained in the water-dispersible resin (A) used in the present
invention.
Synthesis Example 2 (Synthesis 1 of silicone-modified acrylic

resin fine particles not containing reactive silyl group)
The atmosphere inside a flask equipped with a mechanical
stirrer, a thermometer, a nitrogen gas introducing pipe, a reflux
condenser and a dripping funnel was adequately replaced by "
nitrogen gas, then 10g of AQUALON RN-20 (produced by Dai-Ichi
Kogyo Seiyaku Co., Ltd.), Ig of potassium persulfate and 286g of
purified water were placed, and the temperature was raised to
65°C. Next, a mixed solution containing 150g of methyl
methacrylate, 100g of 2-ethylhexyl acrylate, 20g of acrylic acid,
20g of vinyltriethoxysilane, lOg of AQUALON RN-20, 4g of
potassium persulfate and 398.3g of purified water was poured
dropwise into the flask in 2.5hr. The ingredients were heated
and aged at 80°C for 3hr then cooled, and the pH was adjusted to
7 to 8, using potassium hydroxide. Finally, ethanol which had
been formed in the reaction process was evaporated. The
particle diameter of the resin, measured using MICROTRACK
UPA, was. 130nm. The minimum film forming temperature
(MFT) was 0°C.
Synthesis Example 3 (Synthesis 2 of silicone-modified
acrylic resin fine particles not containing reactive silyl group)
The atmosphere inside a flask equipped with a mechanical
stirrer, a thermometer, a nitrogen gas introducing pipe, a reflux
condenser and a dripping funnel was adequately replaced by
nitrogen gas, then 10 g of AQUALON RN-20 (produced by Dai-Ichi


Kogyo Seiyaku Co., Ltd.), lg of potassium persulfate and 286g of
purified water were placed, and the temperature was raised to
65°C. Next, a mixed solution containing 150g of methyl
methacrylate, lOOg of 2-ethylhexyl acrylate, 20g of acrylic acid,
40g of hexyltrimethoxysilane, lOg of AQUALON RN-20, 4g of
potassium persulfate and 398.3g of purified water was poured
dropwise into the flask in 3hr. The ingredients were heated and
aged at 80°C for 3hr then cooled, and the pH was adjusted to 7 to
8, using potassium hydroxide. Finally, ethanol which had been
formed in the reaction process was evaporated. The particle
diameter of the resin, measured using MICROTRACK UPA, was
148nm. The minimum film forming temperature (MFT) was 0°C.
Synthesis Example 4 (Synthesis of silicone-modified
acrylic resin fine particles containing reactive silyl group)
Silicone-modified acrylic resin fine particles containing a
reactive silyl group were synthesized in accordance with
Examples described in JP-A 06-157861.
The atmosphere inside a flask equipped with a mechanical
stirrer, a thermometer, a nitrogen gas introducing pipe, a reflux
condenser and a dripping funnel was adequately replaced by
nitrogen gas, then lOOg of purified water, 3g of sodium
dodecylbenzenesulfonate and lg of polyethylene glycol
nonylphenyl ether were placed, with the addition of lg of
ammonium persulfate and 0.2g of sodium hydrogen sulfite, and


the temperature was raised to 60°C. Next, 30g of butyl acrylate,
40g of methyl methacrylate, 19g of butyl methacrylate, 10g of
vinylsilanetriol potassium salt and lg of
3-methacxyloxypropylmethyldimethoxysilane were poured
dropwise into the flask in 3hr. On this occasion, the solution for
polymerization reaction was polymerized, as its pH was adjusted
to 7 using ammonia aqueous solution. The particle diameter of
the resin, measured using MICROTEACK UPA, was 160nm.
The following explains Examples and Comparative
Examples of the present invention; however, it should be noted
that the present invention is not confined to these Examples and
Comparative Examples. It should also be noted that the
amounts of components mentioned in Examples are based upon
mass.
Ink compositions according to the following formulations
were prepared, and they were each mixed into a lithium
hydroxide 1.0% aqueous solution.such that their pH values
became 9. Thereafter, the solutions were filtered using a
membrane filter of 0.8µm in average pore diameter, and ink
compositions were thus obtained.
The following explains the present invention more
specifically by means of Ink Production Examples; however, it
should be noted that the present invention is not confined to
these Ink Production Examples. It should also be noted that the


amounts (%) of components mentioned below are based upon
mass.
(Ink Production Example 1) Black ink 1
The carbon black produced in Preparation Example 1
8.5% (as a solid content)
1,3-butanediol 15%
Glycerin 15%
2-pyrrolidone 2%
The compound represented by Structural Formula (1)
shown below (R1: CH3, R2: H, Rf: C2F6, m: 16, n: 6) 1%
2-ethyM,3-he:xanediol 2%
A total of 100% was made by addition of ion-exchange
water.

Structural Formula (1)
(In Structural Formula (1), R1 denotes any one of a hydrogen
atom, an alkyl group and a perfluoroalkyl group, R2 denotes any
one of a hydrogen atom, an alkyl group and a fluorine-containing
group, Rf denotes a fluorine-containing group, and m and n each

denote an integer of 1 or greater.)
(Ink Production Example 2) Yellow ink 1
The yellow pigment dispersion solution produced in
Preparation Example 2 5.5% (as a solid content)
1,3-butane diol 20%
Glycerin 20%
2-pyrrolidone 1%
The compound represented by Structural Formula (1)
shown above (R1: CH3, E2: H, Rf- C2F5, m- 16, n: 6) 1%
2,2,4-trimethyl-1,3-pentanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 3) Magenta ink 1
The magenta pigment dispersion solution produced in
Preparation Example 3 7.5% (as a solid content)
Triethylene glycol isobutyl ether 2%
Glycerin 20%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 16, n: 6) 1%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 4) Cyan ink 1
The cyan pigment dispersion solution produced in


Preparation Example 4 5.5% (as a solid content)
3-methyl-1,3-butanediol 15%
Glycerin 20%
The compound represented by Structural Formula (1)
shown above (B1= CH3, R2: H, Rf: C2F5, m: 16, n: 6) 1%
2-ethyl-13-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 5) Cyan ink 2
The cyan pigment dispersion solution produced in
Preparation Example 5 5% (as a solid content)
1,6-hexanediol 20%
Glycerin 15%
The compound represented by Structural Formula (1)
shown above (R1- CF3, R2: H, Rf: CF3, m= 20, n: 4) 0.5%
S-386 (produced by Asahi Glass Co., Ltd.) 0.3%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 6) Magenta ink 2
The magenta pigment dispersion solution produced in
Preparation Example 6 7.5% (as a solid content)
Dipropylene glycol 15%
Glycerin 20%


The compound represented by Structural Formula (1)
shown above (R1: CF3, R2: H, Rf: CF3, m: 20, n: 4) 0.5%
FSN-100 (produced by E. I. du Pont de Nemours and
Company) 0.5%
2-ethyl-1,3-h.exanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 7) Yellow ink 2
The yellow pigment dispersion solution produced in
Preparation Example 7 5% (as a solid content)
2-methyl-2,4-pentanediol 10%
Glycerin 20%
The compound represented by Structural Formula (1)
shown above (R1: CF3, R2: H, Rf: CF3, m: 20, n: 4) 1.5%
2,2,4-trimethyl-1,3-pentanediol 1%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 8) Black ink 2
The black pigment dispersion solution produced in
Preparation Example 8 8% (as a solid content)
1,6-hexanediol 20%
Glycerin 12%
The compound represented by Structural Formula (1)
shown above (R1= CF3; R2: H, Rf: CF3, m.: 20, n: 4) 1.5%


2-ethyM,3-hexanediol 2.5%
A total of 100% was made by addition of ion-exchange
■water.
(Comparative Production Example 1) Comparative pigment black
ink 1
A black ink was obtained in a manner similar to Ink
Production Example 1, except that ECTD-3NEX (an anionic
surfactant, produced by Nikko Chemicals Co., Ltd.) was used
instead of the compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rfs: C2F5, m: 16, n- 6).
(Comparative Production Example 2) Comparative pigment
yellow ink 1
A yellow ink was obtained in a manner similar to Ink
Production Example 2, except that ECTD-6NEX (an anionic
surfactant, produced by Nikko Chemicals Co., Ltd.) was used
instead of the compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 16, n: 6).
(Comparative Production Example 3) Comparative pigment
magenta ink 1
A magenta ink was obtained in a manner similar to Ink
Production Example 3, except that DISPANOL TOC (a nonionic
surfactant, produced by Nippon Oil & Fats Co., Ltd.) was used
instead of the compound represented by Structural Formula (1)
shown above (R1= CH3, B2: H, Rf: C2F5, m: 16, n: 6).


(Comparative Production Example 4) Comparative pigment cyan
inkl
A cyan ink was obtained in a manner similar to Ink
Production Example 4, except that DISPANOL TOC (a nonionic
surfactant, produced by Nippon Oil & Fats Co., Ltd.) was used
instead of the compound represented by Structural Formula (1)
shown above (R1- CH3, R2: H, Rf: C2F5, m: 16, n= 6).
The following explains the ink compositions, as the inks of
Ink Production Examples and Comparative Production Examples
of the present invention are shown in Table 1.
The surface tension and viscosity of each ink are shown in
Table 1.
The surface tension of each ink was measured using
CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. The
viscosity of each ink was measured using the R-type viscometer
RC-500 manufactured by TOKI SANGYO CO., LTD.



Next, ink sets of Examples 1 and 2 and Comparative
Example 1 are shown in Table 2.



(Printer Used for Printing)
Printing was carried out on sheets of the following plain
paper, using the printer in FIGS. 3 and 4 explained in detail in
the present invention.
(Paper Used for Printing)
As paper for the printing test, MY PAPER (produced by
NBS Ricoh Co., Ltd.) was used.
As to a printing pattern, printing was carried out using the
inks of black, yellow, magenta and cyan of the present invention
at a duty of 100%.
As to printing conditions, the recording density was 300dpi,
and one-pass printing was employed.
After printed images had been dried, the images were
holistically examined for bleeding on boundaries between each
two colors combined together, image bleeding and image density
by visual observation and by a reflective color spectrophotometric
colorimetry •densitometer (manufactured by X-Rite, Inc.), and the
images were judged in accordance with the following evaluation
criteria.
(1) Clarity of image (feathering and color bleeding)
Evaluation Criteria
A: all sheets of paper exhibited clear printing without
bleeding
B: bleeding in the form of beards was seen on some sheets


of paper (recycled paper)
C: bleeding in the form of beards was seen on all sheets of
paper
D: bleeding arose to such, an extent that outlines of
letters/characters were unclear
(2) Image density
The optical densities of solid image portions of each color
after printing were measured using X-RITE 932. The evaluation
results are shown in Table 3.

(Ink Production Example 9) Black ink 3
The carbon black produced in Preparation Example 1
8% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 2
4% (as a solid content)

3-methyM,3-butanediol 8%
Glycerin 10%
2-pyrrolidone 2%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf- C2F5, m: 16, n: 6) 0.5%
2,2,4-trimethyl-1,3-pentanediol 1.5%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 10) Yellow ink 3
The yellow pigment dispersion solution produced in
Preparation Example 2 5% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 1
10% (as a solid content)
1,3-butanediol 10%
Glycerin 10%
2-pyrrolidone 1%
The compound represented by Structural Formula (1)
shown above (R1= CH3, R2: H, Rf C2F5, m: 16, n: 6) 1%
2,2,4-trimethyM,3-pentanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 11) Magenta ink 3
The magenta pigment dispersion solution produced in
Preparation Example 3 6% (as a solid content)


The acrylic-silieone xesin emulsion of Synthesis Example 3
15% (as a solid content)
Triethylene glycol isobutyl ether 2%
Glycerin 15%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 16, n- 6) 1%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 12) Cyan ink 3
The cyan pigment dispersion solution produced in
Preparation Example 4 4% (as a solid content)
The acrylic-silieone resin emulsion of Synthesis Example 4
15% (as a solid content)
3-methyM,3-butanediol 10%
Glycerin 10%
The compound represented by Structural.Formula (1)
shown above (R1: CH3, R2: H, Rf C2F5, m: 16, n: 6) 0.5%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 13) Cyan ink 4
The cyan pigment dispersion solution produced in
Preparation Example 5 3.5% (as a solid content)


The acrylic-silicone resin emulsion of Synthesis Example 1
10% (as a solid content)
1,6-hexanediol 20%
Glycerin 8%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 10) 1.5%
FS-300 (produced by E. I. du Pont de Nemours and
Company) 0.3%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 14) Magenta ink 4
The magenta pigment dispersion solution produced in
Preparation Example 6 5% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 1
10% (as a solid content)
Dipropylene glycol 15%
Glycerin 15%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F6, m: 20, n: 10) 1.5%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 15) Yellow ink 4


The yellow pigment dispersion solution produced in
Preparation Example 7 4% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 3
15% (as a solid content)
2-methyl-2,4-pentanediol 10%
Glycerin 10%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 10) 1.5%
2,2,4-trimethyl-1,3-pentanediol 1%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 16) Black ink 4
The black pigment dispersion solution produced in
Preparation Example 8
8% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 2
12% (as a solid content)
1,6-hexanediol 20%
Glycerin 8%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 10) 1.5%
2-ethyM,3-hexanediol 2.5%
A total of 100% was made by addition of ion-exchange
water.


(Ink Production Example 17) Cyan ink 5
The cyan pigment dispersion solution produced in
Preparation Example 9 4% (as a solid content)
W'5025 (urethane resin emulsion, produced by Mitsui
Takeda Chemicals, Inc.) 14% (as a solid content)
1,3-butane diol 20%
Glycerin 8%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 6) 1.5%
2-ethyl-1,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 18) Magenta ink 5
The magenta pigment dispersion solution produced in
Preparation Example 10 7% (as a solid content)
W-5661 (urethane resin emulsion, produced by Mitsui
Takeda Chemicals, Inc.) 10% (as a solid content)
1,5-pentanediol 15%
Glycerin 15%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 6) 1.5%
2-ethyM,3-hexanediol 2%
A total of 100% was made by addition of ion-exchange
water.


(Ink Production Example 19) Yellow ink 5
The yellow pigment dispersion solution produced in
Preparation Example 11 6% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 3
15% (as a solid content)
2-methyl-2,4-pentanediol 10%
Glycerin 10%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 6) 1.5%
2,2,4-trimethyl-1,3-pentanediol 3%
A total of 100% was made by addition of ion-exchange
water.
(Ink Production Example 20) Black ink 5
The black pigment dispersion solution produced in
Preparation Example 1
7% (as a solid content)
The acrylic-silicone resin emulsion of Synthesis Example 2
14% (as a solid content)
l,6hexanediol 10%
Glycerin 10%
The compound represented by Structural Formula (1)
shown above (R1: CH3, R2: H, Rf: C2F5, m: 20, n: 6) 1.5%
2-ethyl-1,3-hexanediol 2.5%
A total of 100% was made by addition of ion-exchange


water.
- Preparation of Comparative Pigment Ink -
(Comparative Production Examples 5 to 8)
(Comparative Production Example 5) Comparative pigment cyan
ink 2
A cyan ink was obtained in a manner similar to Ink
Production Example 17, except that W-5025 was not used.
(Comparative Production Example 6) Comparative pigment
magenta ink 2
A magenta ink was obtained in a manner similar to Ink
Production Example 18, except that W-5661 was not used.
(Comparative Production Example 7) Comparative pigment
yellow ink 2
A yellow ink was obtained in a manner similar to Ink
Production Example 15, except that the acrylic-silicone resin
emulsion of Synthesis Example 3 was not used.
(Comparative Production Example 8) Comparative pigment black
ink 2
A black ink was obtained in a manner similar to Ink
Production Example 16, except that the acrylic-silicone resin
emulsion of Synthesis Example 2 was not used.
- Preparation of Dye Ink -
(Comparative Production Examples 9 to 12)
The following components were mixed together and


sufficiently stirred so as to dissolve, then the mixtures were
filtered under pressure, using FLUOEOPORE FILTER (product
name: manufactured by Sumitomo Electric Industries, Ltd)
having a pore size of 0.45µm, and a dye ink set was thus
prepared.
Dye ink Composition:
(Dyes)
Comparative Production Example 9: Yellow; C.I. Direct
Yellow 86
Comparative Production Example 10: Cyan; C.I. Direct
Blue 199
Comparative Production Example 11: Magenta," C.I. Acid
Red 285
Comparative Production Example 12: Black; C.I. Direct
Black 154
(Ink formulation)
Each of the above-mentioned dyes 4%
Glycerin 10%
Diethylene glycol 5%
Tetramethylurea 5%
F-470 (produced by Dainippon Ink And Chemicals,
Incorporated) 1%
A total of 100% was made by addition of ion-exchange
water.


The following explains the ink compositions, as the inks of
Ink Production Examples and Comparative Production Examples
of the present invention are shown in Table 4.
The surface tension and viscosity of each ink, and the mass
ratio (A)/(B) of each water-dispersible resin (A) to each colorant
(B) are shown in Table 4.
The surface tension of each ink was measured using
CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. The
viscosity of each ink was measured using the R-type viscometer
RC-500 manufactured by TOKI SANGYO CO., LTD.



Next, ink sets of Examples 3 to 9 and Comparative
Examples 2 and 3 are shown in Table 5.



Next, production of original paper (media) will be
explained below.

(Original Paper Production. Example 1) —Production of Support 1—
LBKP 71.23%
NBKP 17.81%
Light calcium carbonate (product name: TP-121, produced by
OEUTAMAKOGYO CO., LTD.) 8.90%
Aluminum sulfate 0.89%
Amphoteric starch (product name: CATO 3210, produced by-
Nippon NSC Ltd.) 0.89%
Neutral rosin sizing agent (product name' NEUSIZE M-10,
produced by Harima Chemicals, Inc.) 0.27%
Yield improver (product name: NR-11LS, produced by HYMO Co.,
Ltd.) 0.01%
A 0.3% slurry containing the components shown above was
made into paper using a fourdrinier machine, the paper was
subjected to machine calendering, and a support 1 having a basis
weight of 79g/m2 was thus produced. Additionally, in a size
pressing process in the papermaking step, a starch oxide aqueous
solution was applied onto the paper at a rate of 1.0g/m2 as a solid
content per side.
(Paper Example 1)
A coating solution having a solid content concentration of


60% was prepared by adding the following- compounds and water
to the support 1 produced in Original Paper Production Example
i: 70 parts of kaolin (1.6 in refractive index, ULTRAWHITE 90
(produced by Engelhard Corporation)) as a pigment, in which
particles that are 2um or less in diameter occupy 97% of all
particles; 30 parts of heavy calcium carbonate (1.6 in refractive
index, CALSHITEG BRILLIANT-15 (produced by Shiraishi Kogyo
Kaisha, Ltd.)) having an average particle diameter of 1.1 µm; 8
parts of styrene-butadiene copolymer emulsion as an adhesive,
having a glass transition temperature (Tg) of-5°C; 1 part of
phosphoric acid-esterified starch; and 0.5 parts of calcium
stearate as an auxiliary agent.
This coating solution was applied onto both surfaces of the
original paper using a blade coater such that the coating layer
thickness was lum per side, and dried with hot air, then the
original paper with this coating solution was subjected to a
supercalendering process, and "recording paper 1" of the present
invention was thus obtained.
Printing was carried out on sheets of this recording paper
1 as a recording medium at an image resolution of 600dpi, with
the ink compositions and the ink sets shown in Tables 1 and 2,
using a 300dpi drop on-demand experimental printer having
nozzles with a nozzle resolution of 384. The amount of ink
attached onto the recording paper 1 was controlled, as the


maximum droplet size was set at 18pl and the total amount of a
secondary color was limited to 140%. When solid images and
letters/characters were printed on a sheet of the recording paper
1, the total amount of ink attached thereto was controlled so as
not to exceed 15g/m2 per area of 300 dots x 300 dots. The quality
and reliability of the images obtained were evaluated. The
results are shown in Table 3. Those evaluated as D are not
suitable as ink-jet images.
(Paper Example 2)
Ink-jet recording was carried out in a manner similar to
Paper Example 1, except that the coating layer thickness was
changed to 10µm per side and "recording paper 2" was thus
obtained.
(Paper Example 3)
Ink-jet recording was carried out in a manner similar to
Paper Example 2, except that the inorganic pigment contained in
the coating solution was changed to 100 parts (as a solid content)
of TA-100 (anatase-type titanium oxide, 2.5 in refractive index,
produced by Fuji Titanium Industry Co., Ltd.) and "recording
paper 3" was thus obtained.
(Paper Example 4)
Ink-jet recording was carried out in a manner similar to
Paper Example 1, except that the inorganic pigment contained in
the coating solution was changed to 100 parts of TP-221 (light


calcium carbonate, 1,6 (1.59) in refractive index, produced by
OKUTAMA KOGYO CO., LTD.), the coating layer thickness was
changed to 5µm per side and "recording paper 4" was thus
obtained.
(Paper Example 5)
Ink-jet recording was carried out in a manner similar to
Paper Example 1, except that the coated paper SPACE DX for
gravure printing (which contains kaolin (1.6 in refractive index)
and calcium carbonate (1.6 in refractive index); produced by
Nippon Paper Group, Inc.) was used (as "recording paper 5") for
the recording medium.
(Paper Example 6)
Ink-jet recording was carried out in a manner similar to
Paper Example 1, except that the coated paper POD GLOSS for
electronic photographs (which contains kaolin (1.6 in refractive
index) and calcium carbonate (1.6 in refractive index); produced
by Oji paper Co., Ltd.) was used (as "recording paper 6") for the
recording medium.
(Paper Example 7)
Ink-jet recording was carried out in a manner similar to
Paper Example 5, except that the surface of the coated paper POD
GLOSS for electronic photographs (which contains kaolin (1.6 in
refractive index) and calcium carbonate (1.6 in refractive index);
produced by Oji paper Co., Ltd.) was polished 20 times with


wrapping paper such that the coating layer thickness was 5.1p.m.
per side, and this paper was used (as "recording paper 7") for the
recording medium.
As to the media of Paper Examples 1 to 7, as a result of
binarizing the observation images with the use of FE-SEM S-4200
manufactured by Hitachi, Ltd., it was confirmed that pores were
lµm or less in diameter, the pores occupied 40% or less of the
media surface in area, which was measured based upon the areas
of pores that occupied the images, and thus all these Paper
Examples satisfied the requirements concerning the pores in the
barrier layers.
The following explains the evaluation items and
evaluation methods concerning Examples and Comparative
Examples shown in Table 5.
(Evaluation Item and Measuring Method Therefor)
(1) Image Quality
1. Ink strike-through
Portions of sheets of paper on the opposite side to green
solid image portions of Examples and Comparative Examples
were measured for image density, and the values obtained by
subtracting the densities of background portions from the
respective image densities were defined as ink strike-through
densities. The images were evaluated in accordance with the
following evaluation criteria, utilizing these ink strike-through


densities and judgment based upon visual observation.
[Evaluation criteria]
A: the ink strike-through density was 0.1 or less, and
uniform printing was yielded without even causing minor ink
strike-through
B: the ink strike-through density was 0.15 or less, and
uniform printing was yielded without even causing minor ink
strike -through
C: the ink strike-through density was 0.15 or less, but
occurrence of minor ink strike-through was confirmed
D: occurrence of serious ink strike-through was confirmed
2. Beading
Green solid image portions of Examples and Comparative
Examples were each visually observed for the extent of beading
and evaluated in accordance with the following evaluation
criteria.
[Evaluation Criteria 1]
5: uniform printing was yielded without causing beading
4: occurrence of slight beading was confirmed, but it was
not at all noticeable
3: occurrence of beading was confirmed, but it does not
impair the image quality
2: occurrence of beading was clearly confirmed
1: occurrence of serious beading was confirmed


[Evaluation Criteria 2]
A: beading > 4.0 rated according to Evaluation Criteria 1
B: 3.0 rated according to Evaluation Criteria 1 4.0 rated according to Evaluation Criteria 1
C: 2.0 rated according to Evaluation Criteria 1 3.0 rated according to Evaluation Criteria 1
D: beading 3. Evaluation of image density
Magenta solid image portions of Examples and
Comparative Examples were measured for optical density, using
X-RITE 932, and evaluated in accordance with the following
evaluation criteria.
[Evaluation Criteria]
A: 1.6 or greater in magenta image density
B: 1.3 or greater in magenta image density
C: 1.0 or greater in magenta image density
D: less than 1.0 in magenta image density
4. Evaluation of glossiness
Image portions of Examples and Comparative Examples
were visually observed for the extent of glossiness and evaluated
in accordance with the following evaluation criteria.
[Evaluation Criteria]
A: high glossiness was confirmed
B: glossiness was confirmed


C: glossiness was slightly confirmed
D: glossiness was not confirmed
(2) Image Reliability

Images of black, cyan, magenta, yellow, red, green and
blue in the shape of squares each having a size of 3cmx3cm were
formed and used for evaluation. Twenty four hours after the
squares had been printed onto sheets of paper, a white cotton
cloth (JISL 0803, Cotton No. 3) stuck onto a friction member with
a two-sided adhesive tape (#4016, t=1.6; produced by Sumitomo
3M Limited) was rubbed back and forth five times against each
square using a clock meter (Model CM-1), then the density of the
coloring material attached to the cotton cloth was measured
using a spectrophotometric colorimetry densitometer (Model-938,
manufactured by X-Rite, Inc.).
[Evaluation Criteria]
A: less than 0.05 in the density of the coloring material
attached to the cotton cloth
B: 0.05 or greater, and less than 0.1 in the density of the
coloring material attached to the cotton cloth
D: 0.1 or greater in the density of the coloring material
attached to the cotton cloth
The evaluation results are shown in Table 6.




CLAIMS
1. An ink-jet recording ink comprising:
water,
a water-soluble organic solvent,
a pigment as a colorant (B), and at least one
fluorocheroical surfactant selected from compounds represented
by Structural Formula (1) below,

Structural Formula (1)
where R1 denotes any one of a hydrogen atom, an alkyl
group and a perfluoroalkyl group, R2 denotes any one of a
hydrogen atom, an alkyl group and a fluorine-containing group,
Rf denotes a fluorine-containing group, and m. and n each denote
an integer of 1 or greater.
2. The ink-jet recording ink according to claim 1, further
comprising a water-dispersible resin (A),
wherein the water-soluble organic solvent is at least one

selected from the group consisting of glycerin,
trimethylolpropane, ethylene glycol, diethylene glycol,
triethylene glycol, propylene glycol, dipropylene glycol,
txipropylene glycol, 1,3-butanediol, 2,3-butanediol,
1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol,
1,6-hexanediol, 2-methyl-2,4-hexanediol, 2-pyxrolidone,
N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone,
tetramethylurea and urea.
3. The ink-jet recording ink according to claim 2, wherein the
water-dispersible resin (A) contains at least one resin emulsion
selected from the group consisting of an anionic self-emulsifiable
ether-based polyurethane resin emulsion and an acrylic-silicone
resin emulsion.
4. An ink-jet recording ink comprising:
water,
a water-soluble organic solvent,
a water-dispersible resin (A),
a pigment as a colorant (B), and
at least one fluorochemical surfactant selected from,
compounds represented by Structural Formula (1) below,
wherein the ink-jet recording ink has a surface tension of
20mN/m to 35mN/m at 25°C and a viscosity of 5mPa-s or greater


at 25°C,
wherein the total amount of the water-dispersible resin (A)
and the colorant (B) present in the ink-jet recording ink is 5% by-
mass to 40% by mass, and a mass ratio (A)/(B) of the
water-dispersible resin (A) to the colorant (B) is in the range of
0.5 to 4, and
wherein the ink-jet recording ink is suitable for ink-jet
recording on an ink-jet recording medium for pigment ink, which
includes a support containing cellulose pulp, and one or more
barrier layers on one or both surfaces of the support, with the one
or more barrier layers containing 30% by mass or more of an
inorganic pigment that is different from an alumina hydrate and
that has a refractive index of 1.5 or greater, and containing 10%
by mass or less of a pigment that has a refractive index of less
than 1.5,

Structural Formula (1)
where R1 denotes any one of a hydrogen atom, an alkyl
group and a perfluoroalkyl group, R2 denotes any one of a

hydrogen atom, an alkyl group and a fluorine-containing group,
Rf denotes a fluorine-containing group, and m and n each, denote
an integer of 1 or greater.
5. An ink-jet recording ink media set comprising:
the ink-jet recording ink according to any one of claims 2 to
4, and
an ink-jet recording medium for pigment ink, .which
comprises a support containing cellulose pulp, and one or more
barrier layers on one or both surfaces of the support, with the one
or more barrier layers containing 30% by mass or more of an
inorganic pigment that is different from an alumina hydrate and
that has a refractive index of 1.5 or greater, and containing 10%
by mass or less of a pigment that has a refractive index of less
than 1.5.
6. An ink-jet recording ink set comprising:
a black ink, and
color inks,
wherein each of the black ink and the color inks is the
ink-jet recording ink according to any one of claims 1 to 4.
7. The ink-jet recording ink according to claim 4, wherein the
one or more barrier layers have a thickness of 10µm or less.


8. An ink cartridge comprising:
a container to house the ink-jet recording ink according to
any one of claims 1 to 4.
9. An ink-jet recording method comprising:
performing recording with the use of the ink-jet recording
ink media set according to claim 5,
wherein the amount of the ink-jet recording ink attached
onto the recording medium is 15g/m2 or less.
10. The ink-jet recording method according to claim 9, further
comprising jetting the ink-jet recording ink so as to form an
image on the recording medium, by applying a stimulus to the
ink-jet recording ink.
11. The ink-jet recording method according to claim 10, •
wherein the stimulus is at least one selected from heat, pressure,
vibration and light.
12. An ink-jet recording apparatus comprising:
an ink jetting unit configured to jet the ink-jet recording
ink according to any one of claims 2 to 4 toward an ink-jet
recording medium for pigment ink and perform printing such that


the amount of the ink-jet recording ink attached onto the
recording medium is 15g/m2 or less,
wherein the ink-jet recording ink, the ink-jet recording
medium and an ink cartridge are installed in the ink-jet
recording apparatus,
wherein the ink-jet recording medium comprises a support
containing cellulose pulp, and one or more barrier layers on one
or both surfaces of the support, with the one or more harrier
layers containing 30% by mass or more of an inorganic pigment
that is different from an alumina hydrate and that has a
refractive index of 1.5 or greater, and containing 10% by mass or
less of a pigment that has a refractive index of less than 1.5, and
wherein the ink cartridge houses the ink-jet recording ink.
13. An ink-jet recording apparatus comprising:
a recording head, and
a unit configured to reverse paper and thereby enable
double-sided printing,
wherein the ink-jet recording ink according to any one of
claims 1 to 4 is ejected as droplets from the recording head so as
to record an image on the paper.


An ink-jet recording ink
including water, a water-soluble organic
solvent, a pigment as a colorant (B), and
at least one fluorochemical surfactant
selected from compounds represented by
Structural Formula (1) below, Structural
Formula (1) where R1 denotes any one
of a hydrogen atom, an alkyl group and a
perfluoroalkyl group, R2 denotes any one
of a hydrogen atom, an alkyl group and
a fluorine-containing group, Rf denotes a
fluorine-containing group, and m and n each
denote an integer of 1 or greater.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=zofaSxVzFDKqObvi2nJnvw==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 271923
Indian Patent Application Number 2309/KOLNP/2010
PG Journal Number 11/2016
Publication Date 11-Mar-2016
Grant Date 10-Mar-2016
Date of Filing 24-Jun-2010
Name of Patentee RICOH COMPANY, LIMITED
Applicant Address 3-6, NAKAMAGOME 1-CHOME, OHTA-KU, TOKYO 1438555, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 NAMBA, MICHIHIKO 770-63, YABE-CHO, TOTSUKA-KU, YOKOHAMA-SHI, KANAGAWA, 2440002 JAPAN
2 MOROHOSHI, NAOYA 319-514, ASHITAKA, NUMAZU-SHI, SHIZUOKA 4100001, JAPAN
3 OHSHIMA, TOHRU LUPINUS 202, 1-7-29, HAYASHI, ATSUGI-SHI, KANGAWA 2430816, JAPAN
4 GOTOH, AKIHIKO BON MAISON HONATSUGI 701 3-14-8, NAKA-CHO, ATSUGI-SHI, KANAGAWA 2430018, JAPAN
5 NAGAI, KIYOFUMI FINE HILL VILLAGE 102, 2212-1, NARUSE, MACHIDA-SHI, TOKYO 194004, JAPAN
PCT International Classification Number C09D 11/00
PCT International Application Number PCT/JP2008/073675
PCT International Filing date 2008-12-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2007-334122 2007-12-26 Japan