Title of Invention

A TONER COMPOSITION CONTAINING POSITIVELY CHARGEABLE MODIFIED PIGMENTS

Abstract A toner composition is disclosed which contains modified pigment particles having attached organic groups and styrenic polymer-based resin particles. The organic groups which are attached to the pigment particles are positively chargeable. Developer compositions containing the toner compositions of the present invention and methods of imaging are also described which use the toner compositions of the present invention.
Full Text TONERS CONTAINING POSITIVELY CHARGE
BACKGROUND OF THE INVENTION FIELD OF THE INVENTION
The present invention relates to toner and developer compositions containing positively chargeable modified pigments. DISCUSSTON OF THE RELATED ART
Electrophotographic processes and image-forming apparatus are widespread nowadays. Particularly, aspects of the xerographic process are set forth in R.M. Schaffert "Electrography", the Focal Press, London & N.Y., enlarged and revised edition, 1975. In electrophotography, an image comprising an electrostatic field pattern (also .referred to as an electrostatic latent image), usually of nonuniform strength, is formed on an insulative surface of an electrophotographic element. The insulative surface comprises a photoconductive layer and an electrically conductive substrate. The electrostatic latent image may be formed by imagewisc photo-induced dissipation of the strength of portions of an electrostatic field of uniform strength previously formed on the insulative surface. Typically, the electrostatic latent image is then visualized by contacting the latent image with an oppositely charged toner powder generally containing a colorant. This process of visualization of a latent image is known as development, and the composition containing the dry toner powder is known as the developer. The toned image is then transferred onto a transfer medium such as paper and fixed thereon by

Development of a latent electrostatic image requires that a charge be developed on the toner particles prior to their deposition on the latent image, and that this charge be opposite to the charge of the latent image. All components of a toner, including binder resin, colorants, charge control agents, waxes and the like, can influence the development of charge on the toner particles. The influence of the colorants on the charging behavior of toner compositions is seldom considered, as there are few known methods to change and control the natural charging behavior of colorants such as carbon black. Thus an unmet need in dry toner technology is for pigments which have certain unique and predictable tribocharging properties.
One approach to meeting this need is to surface-modify known pigments to enhance or change their natural tribocharging properties. For example, Japanese Patent Application Hei 311991]-197961 relates to surface treatment of carbon blacks with amine-funciional silane coupling agents which can, to some extent, overcome the natural tendency of carbon blacks to tribocharge negatively, which makes the carbon blacks more useful as pigments in positive-charging toners. However, it is believed that for such treatments to be effective, the silane coupling agents must form a covalent bond to the surface of the carbon black. The chemical groups believed to be present on the surface of normal carbon black are oxygen-containing groups. Silane coupling agents can form covalent bonds with these groups. Such groups are normally present on the surface of carbon black at low and poorly-controlled levels, making such treatment with silane coupling agents of limited scope and value.

SUMMARY OF THE INVENTION
A feature of the present invention is to provide alternative additives which impart or assist in imparting a positive charge to the toner particles in toner and developer compositions.
Another feature of the present invention is to provide a colorant for use in toner and developer compositions.
Additional features and advantages of the present invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of Ihe elements and combinations particularly pointed out in the written description and appended claims.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention relates to a"toner composition which includes styrenic polymer-based resin particles and modified pigment particles which have at least one organic group attached to the pigment particles, wherein the organic group is positively chargeable.
The present invention also relates to a developer composition which includes carrier particles and the toner composition described above.
In addition, the present invention further relates to a method of imaging which includes the steps of formulating an electrostatic latent image on a negatively charged photoconductive imaging member, effecting the development thereof with a toner composition which includes styrenic polymer-based resin particles and modified pigment particles having attached an organic group that is positively chargeable, and thereafter transferring the developed image onto a suitable substrate.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph (Q/M vs Roll Mill Time) showing the tribocharging behavior of dry powders, including a toner of the present invention, using a standard carrier.
Figure 2 is a graph (Q/M vs Roll Mill Time) showing the tribocharging behavior
of dry powders, including a toner of the present invention, using a positive carrier.
Figure 3 is a graph (Q/M vs Roll Mill Time) showing the tribocharging behavior of dry powders, including a toner of the present invention, using a standard carrier.
Figure 4 is a graph (Q/M vs Roll Mill Time) showing the tribocharging behavior of dry powders, including a toner of the present invention, using a positive carrier.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to toner and developer compositions which include modified pigment particles having atlached at least one organic group that is positively chargeable, and styrenic polymer-based resin particles.
The pigment particles that are modified can be carbon black, cyan, magenta, yellow, blue, green, brown, violet, red, or mixtures thereof. Suitable pigments are pigment particles capable of being modified with attachment of at least one organic group that is positively chargeable. Carbon black is the preferred pigment and examples include, but are not limited to, commercially available forms of carbon black, such as Regal® carbon black from Cabot Corporation. Pigments which may be capable of being modified are described, for instance, in U.S. Patent Nos. 5,484,675; 5,571,654;

5,275,900; and EP 0 723 206 Al, all incorporated in their entirety by reference herein.
As the pigment for black toner compositions, carbon black pigments alone or in combination with blue, green, magnetite or black dyes can be used.
The modified pigment has at least one organic group attached to the pigment particles and the organic group is positively chargeable. The organic group can be attached to the pigment in varying amounts, i.e., low to high amounts, thus allowing fine control over charge modification. The organic group that is attached to the pigment particles can be any group which permits the modified pigment to be positively chargeable once incorporated into the toner or developer composition. Preferably, the organic group comprises an aromatic group or a C1-C20 alkyl group, wherein either group can be substituted or unsubslituted. It is also preferred that the aromatic group or C1-C20 alkyl group is directly attached to the pigment particles. Preferred groups of positively chargeable organic groups are nitrogen containing or phosphorus containing organic groups.
Preferred positive chargeable organic groups have the general structures:

wherein Q represents the elements nitrogen or phosphorus; X represents a counterion such as NO,", Cl", Br", ArSCV, CoCl4, benzoate, and the like - or can be a counterion described in U.S. Patent No. 5,645,967, incorporated in its entirety herein by reference; R1 represents an alkylene group or an arylene group attached to the pigment; and R2, R3, and R4. which may be the same or different, each represent an alkyl group or an aryl

group. Two or more of the R groups can form one or more aliphatic and/or aromatic ringfs), such as QR2R3R4 can form a pyridinium structure and R, can be phenylcne. The ring can include one or more hetero elements. Preferably, the alkylene or alkyl group is a C1-C10 alkylene or alkyl group and the arylene or aryl group is a C6-C20 arylene or aryl group. For the purposes of this invention, aryl and arylene groups include hetemaryl and heteroarylene groups, respectively.
Other preferred organic groups that can be attached to the pigment particles include, but are not limited to the following:





in which Ar represents an aromatic group and Ar1 represents ait aromatic group. The aromatic group includes, but is not limited to, unsaturated cyclic hydrocarbons containing one or more rings. The aromatic group may be substituted or unsubsrituted. Aromatic groups include aryl groups {forexample, phenyl, naphthyl, anthracenyl, and the like), and heteroaryl groups (imidazolyl, pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, iriazinyl, indolyl, and the lite).

A combination of organic groups such as an organic group comprising a pyridyl group and an organic group comprising a quaternary ammonium group can be used.
As described earlier, one or more organic groups can be attached lo the pigment. Also, a modified pigment with untreated pigments), such as conventional carbon black, can be used in the toner composition. Further, two or more modified pigments, each having a different organic group attached to the pigment, can be used. In addition, any combination of the above can be used in the toner compositions of the present invention.
As shown in the examples, various loading levels of the pigment and treatment levels can be used. Certain modified pigments are preferably used at lower levels, while other modified pigments are preferably used at higher levels in the toner compositions.
The following discussion is with reference to the modification of the preferred pigment, carbon black. However, modified pigments other than carbon black can be similarly prepared. The modified carbon black may be prepared preferably by reacting carbon with a diazonium salt in a liquid reaction medium to attach at least one organic group to the surface of the carbon. The diazonium salt may contain the organic group to be attached to the carbon. A diazonium salt is an organic compound having one or more diazonium groups. Preferred reaction media include water, any medium containing water, and any medium containing alcohol. Water is the most preferred medium. Examples of modified carbon black and various preferred methods for their preparation are described in U.S. patent application serial no. 08/356,660 entitled "Reaction of Carbon Black with Diazonium Salts, Resultant Carbon Black Products and Their Uses," filed December 15, 1994 and its continuation-in-part application, U.S. patent application serial no. 08/572,525, filed December 14, 1995, U.S. Patent No. 5,554,739 entitled

"Reaction of Carbon Materials With Diazonium Salts and Resultant Carbon Products " WO 96/18696 and WO 96/18688, all incorporated herein by reference.
In the preferred preparation of the above modified carbon black, the diazonium salt need only be sufficiently stable to allow reaction with the carbon. Thus, that reaction can be carried out with some diazonium salts otherwise considered to be unstable and subject to decomposition. Some decomposition processes may compete with the reaction between the carbon and the diazonium salt and may reduce the total number of organic groups attached to the carbon. Further, the reaction may be carried out at elevated temperatures where many diazonium salts may be susceptible to decomposition. Elevated temperatures may also advantageously increase the solubility of the diazonium salt in the reaction medium and improve its handling during the process. However, elevated temperatures may result in some loss of the diazonium salt due to other decomposition processes. The diazonium salts may be prepared insim. It is preferred that the modified carbon black of the present invention contain no by-products or unattached salts.
With respect to suitable toner resins for use in the toner and developer compositions of the present invention, a styrenic polymer-based is used, such as a styrenated acrylic resin. Examples of preferred styrenic polymer-based resins include, but are not limited to, homopolymers and copolymers of styrene and its derivatives such as: polystyrene; poly-p-cholorostyrene; polyvinyltoluene; styrene-p-chlorostyrene copolymer; and styrenc-vinyltoluene copolymer; copolymers of styrene and acrylic acid esters such as: styrencmethylacrylate copolymer; styrene-ethylacrylate copolymer; and styrene-n-butyl acrylate copolymer, copolymers of styrene and methacrylic acid esters such as: sryrenc-methyl methacrylate copolymer; styrene-cthyl methaciylate copolymer; sryrene-n-butyi methacrylate copolymer; and multi-component copolymers of styrene, acrylic acid

ester and methacrylic acid esters; copolymers of styrenc and other vinyl monomers such
as: styrene-acrylonitrile copolymer, styrene-methyl ether copolymer; styrene-butadienee copolymer; sryrene-vjnyl methyl ketone copolymer; styrene-acrylonitriteindenc copolymer; styrene maleic acid ester copolymer; and the like. These binder resins may be used singly or in combination. Generally, resins particularly suitable for use in xerographic toner manufacturing have a melting point (ring and ball method) in the range of 100°C to 135°C and have a glass transition temperature (Tg) greater than about 60°C. Examples of styrenic polymer-based resin particles and suitable amounts can also be found in U.S. Patent Nos. 5,278,018; 5,510,221; 5,275,900; 5,571,654; 5,484,575; and EP 0 270 066 Al, all incorporated in their entirety by reference herein.
Generally, the modified pigment of the present invention, alone or with other pigments, is present in total amounts of from about 1% by weight to about 30% by weight of the toner or developer composition. The amount of pigment present in the toner composition is preferably from about 0,1 to about 12 wt parts per 100 wt parts of resin. However, lesser or greater amounts of the modified pigment may be used. Also, generally, the toner resin is present in amounts of from about 60% by weight to about 99% by weight of the toner or developer composition.
Optional external additives may also be mixed or blended with the toner compositions of the present invention including carrier additives; additional positive or negative charge controlling agents such as quaternary ammonium salts, pyridinum salts, sulfates, phosphates, and carboxylates; flow aid additives; silicone oils; waxes such as commercially available polypropylenes and polyethylenes; magnetite; and other known additives. Generally, these additives arc present In amounts of from about 0.05% by weight to about 30% by weight, however, lesser or greater amounts of the additives may

be selected depending on the particular system and desired properties. Specific examples of additives and amounts are also described in the patents and the European patent application mentioned above and incorporated herein by reference.
The toner compositions can be prepared by a number of known methods, such as admixing and heating the resin, the modified pigment particles, optional charge enhancing additives and other additives in conventional melt extrusion devices and related equipment. Other methods include spray drying and the like. Compounding of the modified pigment and other ingredients with the resin is generally followed by mechanical attrition and classification to provide toner particles having a desired particle size and particle size distribution. Conventional equipment for dry blending of powders may be used for mixing or blending the modified pigment particles with the resin. Again, conventional methods of preparing toner and developer compositions can be used and arc described in the patents and European application described above and incorporated herein by reference.
In more detail, the toner material can be prepared by dry blending the binder resin with all other ingredients, including the pigment, and then melt-extruding in a high shear mixer to form a homogeneously mixed mass. During this process the components are held at a temperature above the melting point of the binder resin, and those components that are insoluble in the resin arc ground so that their average particle si2c is reduced. This homogeneously mixed mass is then allowed to cool and solidify, after which it is pre-ground to an average particle size of about 100 microns. This material is then further subjected to particle size reduction until its average particle size meets the size range specification required for classification. A variety of classifying techniques may be used. The preferred type is an air classification type. By this method, particles in the ground

material which arc too large or too small are segregated from the portion of the material
which is of the desired particle size range.
The toner composition of the present invention may be used alone in monocomponcnt developers or may be mixed with suitable carrier particles to form dual component developers. The carrier vehicles which can be used to form dual component developer compositions can be selected from various materials. Such materials typically include carrier core particles and core particles overcoated with a thin layer of film-forming resin to help establish the correct triboelectric relationship and charge level with the toner employed. Suitable carriers for two component toner compositions include iron powder, glass beads, crystals of inorganic salts, ferrite powder, nickel powder, all of which are typically coated with resin coating such as an epoxy or fluorocarbon resin. Examples of carrier particles and coatings that can be used and are described in the patents and European application described above and incorporated herein by reference.
, The present invention is further directed to a method of imaging which includes formulating an electrostatic latent image on a negatively charged photoconductive imaging member, affecting the development thereof with toner composition comprising resin particles and modified pigment particles, and thereafter transferring the developed image onto a suitable substrate. Conventional methods of imaging can be used, such as shown in the patents and European patent application described above.
The present invention will be further clarified by the following examples which are intended to be purely exemplary of the present invention.

EXAMPLES
.Example 1 Preparation of a modified carijon black product
A solution of 2.83 g of sodium nitrite in about 100 g of water was added slowly to a mixture of 200 g of carbon black, 3.95 g of concentrated HC1, 4.48 g of p-phenylenediamine and I.8L of water that was stirring at about 70"=C. The carbon black, Rcgal*330 carbon black, had a surface area of 94 mVg and a DBPA of 65 mL/lOOg. After stirring for about two hours, the mixture was allowed to stand overnight. The aqueous layer was decanted, and the remainder of the material was dried at 70°C. The product had attached C6R4NH2 groups.
Example 2 Preparation of a modified carbon black product
A solution of 2.84 g of sodium nitrite in about 100 g of water was added slowly to a mixture of 200 g of carbon black, 3.94 g of concentrated HC1, 2.22 g of p-phenylenediamine, 4,34 g of 4-aminophenylpyridinium chloride and 1.8 L of water that was stirring at about 70°C. The carbon black, Rcgal®330 carbon black, had a surface area of 94 mVg and a DBPA of 65 mL/100g. After stirring for two hours, the mixture was allowed lo stand overnight. The aqueous layer was decanted, and the remainder of the material was dried at 70oC. The product had attached C6H4NH2 and C6H4NC5H5 Cl" groups.

Example 3 (Comparative) Preparation of a, toner
A black toner powder was prepared by the conventional technique of melt-mixing, extruding, pre-grinding, jetrailling and classifying. Thus, 8 wt% of Regal®330 carbon black (unmodified) (available from Cabot Corporation, Boston, Massachusetts) was dry blended with 92 wt% of Dialec 1601 styrenated acrylic polymer (available from Polytribo Inc, Bristol, Pennsylvania) and melt-extruded in a B&P 19-millimetcr extruder (available from B&P Process Equipment & Systems, LLC, Saginaw, Michigan) operating in a typical screw and paddle configuration ■ The resulting carbon black/polymer product was pre-ground in a Kiups Mini Blender, then jetmilled and classified using a Majac A-12 and mini-grinder to form a black toner powder having an average particle size of about 13 microns, as determined using a Coulter Multisizer Particle Size Analyzer. This toner is referred to as Sample 2 in Table 1 of Example 5.
Developer compositions were prepared by mixing the toner composition described above either with a positive charging fenite powder, or a standard ferrite powder (both available from Powdertech, Inc., Valparaiso, Indiana), in an amount sufficient to yield a 2.0 wt9S loading.
Tribocharge measurements were made by tumble blending the above developer compositions (toner plus carrier) in stainless steel vessels on a roll mill. At blending times of 15 minutes, 30 minutes, 45 minutes, and 60 minutes, a small sample of the developer composition was removed and its charge-to-mass ratio (Q/M) was determined by the Faraday cage tribo blow-off method using a Vertex T-150 tribocharge tester (available from Vertex, Inc., Yukon, Pennsylvania).

Preparation of a Tony
A black toner powder was prepared by the conventional technique of melt-irdxing, extruding, pre-grinding, jetmilling and classifying. Thus 8 wt% of the modified carbon black prepared in Example 1 was dry blended with 92 wt% of Dialec J601 styrenaled acrylic polymer (available from Polytribo Inc, Bristol, Pennsylvania) and melt-extruded in a B&P 19-miliimcter extruder (available from B&P Process Equipment &. Systems, LLC, Saginaw, Michigan) operating in a typical screw and paddle configuration. The resulting carbon black/polymer product was pre-ground in a Krups Mini Blender, then jctmilled and classified using a Majac A-12 and mini-grinder to form a black loner powder having an average particle size of about 12 microns, as determined using a Coulter Multisizer Particle Size Analyzer. This toner is referred to as Sample 3 in Table 1 of Example 5.
Developer compositions were prepared by mixing the toner composition described above either with a positive charging ferrite powder, or a standard ferrite powder (both available from Powdertcch, Inc., Valparaiso, Indiana), in an amount sufficient to yield a 2.0 wt% loading.
Tribocharge measurements were made by tumble blending die above developer compositions (toner plus carrier) in stainless steel vessels on a roll mill. At blending times of 15 minutes, 30 minutes, 45 minutes, and 60 minutes, a small sample of the developer composition was removed and its charge-to-mass ratio (Q/M) was determined by the Faraday cage tribo blow-off method using a Vertex T-150 tribocharge tester (available from Vertex, Inc., Yukon, Pennsylvania).
The results of tribocharge testing of Sample 3 using a standard ferrite carrier are presented in Figure 1. Also in Figure 1 are shown for comparative purposes the

tribocharging behavior of a pseudo toner containing a jet-milled Dialec 1601 resin which was combined with a standard fenite. carrier in an amount to yield a 2.0 wt.% loading (Sample 1) and the loner of Example 3 combined with a standard ferrite carrier in an amount to yield a 2.0 wt.% loading. After IS minutes the charge on Sample 1 was strongly negative at about -20 microcoulombs/g, and was slightly more negative after 60 minutes. In comparison the charges at 15 minutes on Samples 2 and 3 were more than 15 micTocoulombs/g more positive and were nearly equal. After 60 minutes, however, the charge on sample 2 (confining unmodified Kegal*330) became more negative by more than 12 microcoulombs/g while the charge on Sample 3 (containing the modified carbon black from Example 1) decreased by less than 3 microcoulombs/g.
The results of tribochaxge testing of Sample 3 using a positive fenite carrier are presented in Figure 2. Also in Figure 2 are shown for comparative purposes the tribocharging behavior of a pseudo toner containing a jetmilled Dialec 1601 resin (Sample 1) which was combined with a positive fenite carrier in an amount to yield a 2.0 wt.% loading and the toner of Example 3 combined with a positive ferrite carrier in an amount to yield a 2.0 wt.% loading. {Sample 2). After 15 minutes the charge on Sample 1 was strongly negative, while by comparison the charge on Sample 2 was more positive by 20 microcoulombs/g, and the charge on Sample 3 was more positive by 30 microcoulombs/g. After 60 minutes the charge on Sample 2 (containing unmodified Regal°330) became more negative by about 10 microcoulombs/g, while the charge on Sample 3 (containing the modified carbon black from Example 1) actually became slightly more positive, by less than 3 microcoulombs/g.

Example 5 Preparation of a Toner
A black toner powder was prepared by the conventional technique of melt-mixing,
extruding, prc-grinding, jetmilring and classifying. Thus, 8 wt% of the modified carbon black prepared in Example 2 was diy blended with 92 wt% of Dialec 1601 styrcnated acrylic polymer (available from Potytribo Inc, Bristol, Pennsylvania) and melt-extruded in a B&P 19-millimeter extruder (available from B&P Process Equipment and Systems, LLC, Saginaw, Michigan) operating in a typical screw and paddle configuration. The resulting carbon black/polymer product was prc-ground in a Knips Mini Blender, then jetmilled and classified using a Majac A-12 and mini-grinder to form a black toner powder having an average particle size of about 12 microns, as determined using a Coulter Multisizer Particle Size Analyzer. This toner is referred to as Sample 4 in Table 1 of Example 5.
Developer compositions were prepared by mixing the toner composition described above either with a positive charging ferritc powder, or a standard ferrite powder (both available from Powdertcch, Inc., Valparaiso, Indiana), in an amount sufficient to yield a 2.0 wt% loading.
Tribocharge measurements were made by tumble blending the above developer compositions (toner plus carrier) in stainless steel vessels on a roll mill. At blending times of 15 minutes, 30 minutes, 45 minutes and, 60 minutes, a small sample of the developer composition was removed and its chargc-to-mass ratio (Q/M) was determined by the Faraday cage tribe blow-off method using a Vertex T-150 tribocharge tester (available from Vertex, Inc., Yukon, Pennsylvania).

The results of tribocharge testing of Sample 4 against a standard ferrite carrier
are presented in Figure 3. Also in Figure 3 are shown for comparative purposes the
tribocharging behavior of a pseudo toner containing a jet-milled Diaiec 1601 resin
(Sample 1) which was combined with a standard ferrite carrier in an amount to yield a 2.0
wt.% loading and the toner of Example 3 (Sample 2) which was combined with a
standard ferrite carrier in an amount to yield a 2.0 wt. % loading. After 15 minutes the
charge on Sample 1 was strongly negative at about -20 microcoulombs/g and was slightly
more negative at 60 minutes. In comparison, the charge at 15 minutes on Sample 2 was
more than 15 microcoulombs/g more positive, and the charge on Sample 4 was more than
25 microcoulombs/g more positive. After 60 minutes, however, the charge on sample 2
(containing unmodified Regal®330) became more negative by more than 12
microcoulombs/g while die charge on Sample 4 (containing the modified carbon black
from Example 2) decreased by less than 3 microcoulombs/g.
The results of tribocharge testing of Sample 4 against a positive ferrite carrier arc
presented in Figure 4. Also in Figure 4 are shown for comparative purposes the
Iribocharging behavior of a pseudo toner containing a jet-milled Dialec 1601 resin
(Sample 1) which was combined with a positive ferrite carrier in an amount to uield a 2.0
wt. % loading and the toner of Example 3 (Sample 2) which was combined with a positive
ferrite carrier in an amount to yield a 2,0 wt-% loading. After 15 minutes the charge on
Sample 1 is strongly negative at about -30 microcoulombs/g and is slightly more negative
at 60 minutes. In comparison the charge at 15 minutes on Sample 2 was more positive by
about 20 microcoulombs/g, and the charge on Sample 4 was more positive by 45
microcoulombs/g. After 60 minutes the charge on Sample 2 (containing unmodified
Regal®330) became more negative by about 10 microcoulombs/g, while the charge on

Sample 4 (containing the modified carbon black from Example 2) remains at about the same positive level of +15 roicrocoulombs/g.

Example 6 Preparation of a carbon black product
Silver nitrite (7.7 part?) was added to a solution of 11.8 parts of N-methyl-3-aminopyridinium iodide in about 50 parts of water. After stirring for one hour, the mixture was filtered and the precipitate was washed with abottt 100 parts of water. The liquids were combined to give a solution of N-methyl-3-aminopyridinium nitrite.
A pelletuer was charged with 500 parts of a carbon black with a surface area of 94 m:/g and a DBPA of 65 mL/100g and 5.6 parts of phenylencdiamine. The pelletizer was run at about 400 rpm for about 30 sec. The N-methyl-3-aminopyridimum nitrite solution was added while the pelletizer was mixing, and mixing was continued for two minutes at 400 rpm. The pelletizer speed was increased to 700 rpm, and a solution of 9.1 parts concentrated HN03 in 50 parts water, 25 parts water, a solution of 3.6 parts NaNO, in 50 parts water, and then 30 parts water were added successively with two minutes following each addition. The


resulting product was dried under vacuum at 55 "C. The product had attached C6H4NH2 and C5H4NCH3+ NO3groups.
Example 7 Preparation of a carbon black product
A solution of 2.1 g of nitric acid in 30 g of water was gradually added to a suspension of 19.5 g of N-(4-aminophenyl)pyridinium nitrite, 200 g of carbon black and I L of water that was stirring at about 65 X. The carbon black had a surface area of 94 m3/g andaDBPA of 65 mL/100g. After stirring for an additional 50 min, the product was dried in an over at 76 "C. The product had attached C5H5NC5H5NO3 groups.
Bitample 8 Preparation of a carbon black product
A pelletizer was charged with 500 parts of a carbon black with a surface area of 94 m3/g and a DBPA of 65 mL/100g, 2.9 parts of p-phenylcnediamine and 5.2 parts of N-(4-aminophenyI)pyridinium chloride. The pelletizer was run at about 400 rpm for about two min. As the pelletizer continued to run, a solution of 5.0 parts concentrated HC1 in about 125 parts water, about 25 parts water, a solution of 3.6 parts of NaNO2in aboutl25 parts of water and about 25 parts of water were added in succession. Mixing was continued at 700 rpm for an additional six minurcs. The resulting product was dried at 65 "C The product had attached C6H,NH2 and C6H4NC5K/ Cl groups.

Example _9_ Preparation of a carbon black product
A peiietizer was charged with 400 parts of a carbon black with a surface area ; 94 mVg and a DBPA of 65 mL/100g and 7.6 parts of 3-aminopyridine. The felletizer was run at about 200 rpm for about one min. A solution of 7.2 parts of ancentratcd nitric acid in about 50 parti of water was heated to about 55 eC and then dded to the peiietizer while it was mixing at 400 rpm. The mixing was continued or about one minute. As the peiietizer continued to run, a solution of 5.7 parts of NaNO2 in about 50 parts of water at 60 "C was added followed by 100 parts of 65 "C valer. The resulting product was dried under vacuum at 70 "C. The product had itlached C5H4N groups.
Example 10 Preparation of a carbon black product
A peiietizer was charged with 800 parts of a carbon black with a surface area of 94 nr7g and a DBPA of 65 mL/100g and 30 parts of 4"aminoacctanilide. The peiietizer was run at about 400 rpm for about one min. The peiietizer speed was increased to 700 rpm and a solution of 19.S parts concentrated HC1 in about 165 parts water, about 55 parts water, a solution of 13.9 parts of NaN02 in about 165 parts of water, and about 130 parts of water were added in succession with one to two minutes after each addition. The resulting material was boiled in 3.5 L of 5M HC1 overnight, cooled and filtered. After washing three times with 3.5 L of water, once with 4L of ethanoi and once with 5L of water, the product was dried under vacuum. The product had attached C5H4NH3 Cl groups.

Example 3 J Preparation and evaluation of a toner
The carbon black product of Example 6 was incorporated into a pseudo toner
and evaluated using the method of Example 4. After rolling for 60 minutes with a
positive carrier, a toner incorporating the carbon black product of Example 6 had a
tribocharge of 16 µC/g. A control toner that had Regal 330 carbon black
incorporated in it gave a tribocharge of 1 µC/g against the same carrier.
Example 12 Preparation and evaluation of Toner.1;
Black toners were prepared by the conventional technique of melt-mixing, extruding, pregrinding, jetmilling and classifying. Thus, 8 parts of carbon black and 92 parts of Dialec 1601 styrenated acrylic polymer were melt extruded with a Werner and Pfleidercr ZSK-30 twin screw extruder. The resulting black/polymer product was granulated in a Kayncss mini granulator, and then jermiJled and classified using a Hosokawa Alpine AFG Model 100 mill to form a black toner powder having an average particle- size of about 8 microns, as determined using a Coulter Multisizer II
Developer compositions were prepared by mixing the toner composition with a positive charging (Type 13) carrier available from Vertex in an amount sufficient to yield a 2.0 wt% loading. Tribocharge measurements were made by tumble blending the developer compositions (toner plus carrier) in glass vessels on a roll mill. After blending for 60 minutes, a small sample of the developer composition was removed and its charge to mass ratio (Q/M) was determined by the Faraday cage blow off

method using a Vertex T-150 tribocharge tester. The results shown below indicate that the samples charged more positively than the control.

Example 13 Preparation and evaluation of toners
The carbon black product of Example 9 and Regal 330 carbon black were incorporated into toners using the method of Example 12 using blends of the two carbons. The total carbon content was 4 parts and the resin coutent was 96 parts. These results show that the toners containing the carbon black product of Example 9 charged more positively than the toner containing only the control black.

Example.14 Preparation of a carbon black product
Silver nitrite (7,7 parts) was added to a solution of 13,9 parts of 4-aminophenyltri methyl-ammonium iodide in 40 parts of water. After stirring for three hours, the mixture was filtered and the precipitate was washed with 60 parts of

water. The liquids were combined to give a solution of 4-arninophenyltrimethylammonium nitrite.
A pelletizer was charged with 500 parts of a carbon black with a surface area
of 94 m3/g and a DBPA of 65 mL/100g and 5.6 parts of phenylenediamine. The pelletizer was run at about 400 rpm for about 30 sec. The 4-aminophenyltrimethyiamrnonium nitrite solution was added while the pelletizer was mixing, and mixing was continued for two minutes at 400 rpm. The pelletizer speed was increased to 700 rpm, and a solution of 9.1 parts concentrated HNO3 in 75 parts water, 30 parts water, a solution of 3.6 parts NaNO2 in 75 parts water, and then 30 parts water were added successively with two minutes following each addition. The resulting product was dried under vacuum at 55 "C. The product had attached CSH,NR: and C^NCCHOJ* NO; groups.
The carbon black product of this Example was incorporated into a pseudo loner and evaluated using the method of Example 4. After rolling for 60 minutes with a positive carrier, a toner incorporating the carbon black product of this Example had a tribocharge of 2 ^C/g. A control toner that had Regal 330 carbon black incorporated in it gave a tribocharge of 1 pC/g against the same carrier.
Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following ciaims.


WE CLAIM:
1. A toner composition containing positively chargeable modified pigments comprising a) styrenic polymer-based resin particles and b) modified pigment particles having attached at least one organic group wherein said organic group is positively chargeable and comprises at least one aromatic group or a C1-C20 alkyl group attached to the pigment particles, wherein said organic group has the formula:

or said organic group is -C5H4N, -C6H4NH2, -C5H4(NC5H5)+X" or both wherein Q represents the elements nitrogen or phosphorus; X represents a counterion; R1, represents an alkylene group or an arylene group attached to the pigment; and R2, R3, and R4, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
The toner composition as claimed in claim 1, wherein said organic group has the formula:

wherein Q represents the elements nitrogen or phosphorus; R1 represents an alkylene group or an arylene group attached to the pigment; and R2 and R3, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.

3. The toner composition as claimed in claim 1, wherein said organic group has
the formula:

wherein Q represents the elements nitrogen or phosphorus; X represents a counterion; R1, represents an alkylene group or an arylene group attached to the pigment; and R2r R.3, and R4, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
4. The toner composition as claimed in claim 1, wherein a modified pigment particle having attached -C5H4N(CH3)+X" or -C5H4(NC5H5)+X, wherein X" is a counterion group.
5. The toner composition as claimed in claim 1, wherein it comprises modified pigment particles having attached -C2H4NH2 groups.
6. The toner composition as claimed in claim 1, wherein said organic group comprises a pyridyl group.
7. The toner composition as claimed in claim 1, wherein the counterion is CI", N03- Br-, or ArS03".
8. The toner composition as claimed in claim 1, wherein said organic group comprises a pyridyl group and a modified pigment particle having attached an organic group comprising a quaternary ammonium group.

9. The toner composition as claimed in claim 1, wherein said organic group is -C6H4NH2, -C6H4(NC5H5)+X" or both, where X" is a counterion.
10. The toner composition as claimed in claim 1, wherein said aromatic or C1-20 alkyl group is directly attached to said pigment.
11. A method of imaging comprising the step of formulating an electrostatic latent image on a negatively charged photoconductive imaging member, developing the image formed with a toner composition as claimed in claim 1, and transferring the developed image onto a substrate.
12. The method as claimed in claim 11, wherein said organic group has the
formula:

wherein Q represents the elements nitrogen or phosphorus; R1 represents an alkylene group or an arylene group attached to the pigment; and K2 and R3, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
13. The method as claimed in claim II, wherein said organic group has the
formula:


wherein Q represents the elements nitrogen or phosphorus; X represents a counterion; R1, represents an alkylene group or an arylene group attached to the pigment; and R2, R3, and R4, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
14. The method claimed in claim 11, wherein said organic group is -C6H4NH2, -C6H4(NC5H5)+X" or both, where X is a counterion.
15. The method as claimed in claim 11, wherein said aromatic or Q-zo alkyl group is directly attached to said pigment.
16. A developer composition comprising a toner composition as claimed in claim 1 and carrier particles.
17. The developer composition as claimed in claim 16, wherein said organic group has the formula:

wherein Q represents the elements nitrogen or phosphorus; R] represents an alkylene group or an arylene group attached to the pigment; and R2 and R3, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
18. The developer composition as claimed in claim 16, wherein said organic group
has the formula:


wherein Q represents the elements nitrogen or phosphorus; X represents a counterion; R1 represents an alkylene group or an arylene group attached to the pigment; and R2, R3, and R4, which may be the same or different, each represent an alkyl group or an aryl group or form a ring.
19. A developer composition comprising the toner composition as claimed in claim
6 and carrier particles.
20. The developer composition as claimed in claim 16, wherein the counterion is
C1-, N03", Br", or ArS0321. The developer composition as claimed in claim 10, wherein said organic group
is -QH4NH2, -C6H4(NC5H5)+X" or both, where X" is a counterion.
22. The developer composition as claimed in claim 16, wherein said aromatic or
C1-20 alkyl group is directly attached to said pigment.

Documents:

1628-mas-98 abstract.pdf

1628-mas-98 assignment.pdf

1628-mas-98 claims-duplicate.pdf

1628-mas-98 claims.pdf

1628-mas-98 correspondence-others.pdf

1628-mas-98 correspondence-po.pdf

1628-mas-98 description (complete)-duplicate.pdf

1628-mas-98 description (complete).pdf

1628-mas-98 drawings.pdf

1628-mas-98 form-19.pdf

1628-mas-98 form-2.pdf

1628-mas-98 form-26.pdf

1628-mas-98 form-4.pdf

1628-mas-98 form-6.pdf

1628-mas-98 others.pdf

1628-mas-98 petition.pdf


Patent Number 217250
Indian Patent Application Number 1628/MAS/1998
PG Journal Number 21/2008
Publication Date 23-May-2008
Grant Date 26-Mar-2008
Date of Filing 21-Jul-1998
Name of Patentee CABOT CORPORATION
Applicant Address 75 STATE STREET, BOSTON, MASSACHUSETTS 02109-1806,
Inventors:
# Inventor's Name Inventor's Address
1 CHARLES B LITTLE 3922 ENGLEWOOD DRIVE, CHAMPAIGN, ILLINOIS 61821,
2 JAMES A BELMONT 8 CONANT STREET, ACTON, MASSACHUSETTS 01720,
PCT International Classification Number G03G 9/09
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 08/897,446 1997-07-22 U.S.A.