MX2007013425A - Toner for reduced photoreceptor wear rate - Google Patents

Abstract

An electrophotographic image forming apparatus comprising a photoreceptor, a conductive magnetic brush development system, and a housing in association with the conductive magnetic brush development system for a developer comprising a toner composition having emulsion/aggregation toner particles comprising a gel latex, a high Tg latex, a wax, and a colorant, wherein the wear rate of the photoreceptor is improved.

Description

ORGANIC PIGMENT FOR REDUCED PHOTORRECEPTOR WEAR RATE FIELD OF THE INVENTION Disclosed herein is a developing system having a photoreceptor and an organic emulsion / aggregation pigment comprising a gel latex, a high Tg latex, a wax, and a dye, where the organic pigment particles improve the wear rates of a photoreceptor in a development system.

BACKGROUND OF THE INVENTION U.S. Patent Publication No. 2006-0121384, which is incorporated herein by reference in its entirety, discloses organic pigment compositions and processes, or organic aggregation pigment processes in the emulsion, for preparing compositions of organic pigment comprising a substantially free crosslinking resin, a crosslinked resin, a wax and a dye. U.S. Patent Application No. 11 / 272,720 by Patel et al, which is incorporated herein by reference in its entirety, is directed to organic pigment compositions and processes, such as organic pigment processes of aggregation in the emulsion, for preparing organic pigment compositions comprising a resin Ref. 185448 non-crosslinked high molecular weight such as having a weight average molecular weight of at least 50,000, a wax, and a dye. It is still desirable to improve the components and design parameters of organic pigment EA that can reduce the wear rate of the photoreceptor and provide an increase in photoreceptor life.

SUMMARY OF THE INVENTION In embodiments, an electrophotographic image forming apparatus is disclosed comprising a photoreceptor, a conductive magnetic brush developing system, and a housing in association with the conductive magnetic brush developing system for a developer comprising a organic pigment composition having organic pigment particles in emulsion / aggregation comprising a latex gel, a high Tg latex, a wax and a dye, where the gel latex is present in an amount of about 3 weight percent up to about 30 weight percent of the organic pigment composition, in high Tg latex is present in an amount of about 50 weight percent up to about 95 weight percent of the organic pigment composition, the wax is present in an amount of about 2 weight percent up to about 40 percent in The weight of the organic pigment composition and the colorant is present in an amount of about 1 weight percent to about 25 weight percent of the organic pigment composition. In further embodiments, a developer comprising a support and an organic pigment in the emulsion / aggregation is described, wherein the organic pigment comprises a latex gel, a latex of high Tg, a wax, a dye, and where the latex gel is present in an amount of about 3 weight percent to about 30 weight percent of the organic pigment, in high Tg latex is present in an amount of about 50 weight percent to about 95 weight percent of the organic pigment , the wax is present in an amount of about 2 weight percent to about 40 percent of the organic pigment, and the dye is present in an amount of about 1 weight percent to about 25 weight percent of the organic pigment. In still further embodiments, a method of printing an image based on organic pigment, comprising charging a photoreceptor to a uniform potential, exposing the surface of the photoreceptor charged to a light image to record a latent electrostatic image on the surface of the photoreceptor is described. , reveal the latent electrostatic image by putting the developer in contact with the latent electrostatic image to expose an image, transferring the image to a substrate to form an image based on organic pigment, and fusing the image based on organic pigment to the substrate, where the developer comprises an organic pigment in the emulsion / aggregation having a latex of gel, a latex of Tg high, a wax and a dye, where the residual organic pigment is removed from the photoreceptor with a cleaning device, and where the photoreceptor wear rate is about -0.004 μm / Kcycles to about -0.018 μm / Kcycles.

DETAILED DESCRIPTION OF THE INVENTION Generally, the electrophotographic printing process includes charging a photoconductive member to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive surface is exposed to a luminous image of, for example, a scanning laser beam, a LED source, etc., or an original document being reproduced. This records a latent electrostatic image on the photoconductive surface of the photoreceptor. After the latent electrostatic image is recorded on the photoconductive surface, the latent image is revealed putting the developer comprised of organic pigment in contact with it. Commonly used are two component and one component developer materials. A typical two-component developer material comprises magnetic carriers or carriers having organic pigment particles that adhere triboelectrically thereto. A single component developer material typically comprises organic pigment particles. The organic pigment particles are attracted to the latent image by forming an image of organic pigment powder on the photoconductive surface. The image of organic pigment powder is subsequently transferred to a substrate, such as paper or a copy sheet finally, the organic pigment powder image is heated to permanently merge it to the copy sheet in the image configuration. In a known way to reveal the latent image on the photoreceptor is through the use of one or more magnetic brushes. See, for example, U.S. Patent Nos. 5,416,566, 5,345,298, 4,155,329 and 3,981,272, each of which is incorporated herein by reference in its entirety. In embodiments, the conductive magnetic brush (CMB) developers can be selected by hybrid hop development, developed without hybrid cleaning, and similar processes, refer to U.S. Patent Nos. 4,868,600; 5,010,367; 5,031,570; 5,119,147; 5,144,371 5,172,170; 5,300,992; 5,311,258; 5,212,037; 4,984,019 5,032,872; 5,134,442; 5,153,647; 5,153,648; 5,206,693 5,245,392; 5,253,016, the descriptions of which are fully incorporated herein by reference in their entirety. The aforementioned developers, which may contain a negatively charged organic pigment, are suitable for use with laser or LED printers, discharge area developing with layered flexible photoconductive image forming members, see US Pat. No. 4,265,990, description of which is hereby incorporated herein by reference, and members forming organic photoconductive images with a photogenerating layer and a load carrying layer on a drum, xerography of light lenses, developing of charged area on, for example, photoconductive members inorganics such as selenium, alloys, selenium, such as selenium, arsenic, tellurium, hydrogenated amorphous silicon, xerography of three levels, refer to US Patents Nos. 4,847,655; 4,771,314; 4,833,504; 4,868,608; 4,901,114; 5,061,969; 4,948,686 and 5,171,653, the descriptions of which are fully incorporated herein by reference, full color xerography, and the like. Other members photoconductors of suitable images include an aluminum-based drum photoreceptor. In embodiments, the developers can be selected for image and print forming systems, with conductive magnetic brush developer as illustrated, for example, in U.S. Patent No. 4,678,734, the disclosure of which is hereby incorporated by reference, and where it is allowed in modalities with high development levels, revealed for the substantially complete mentalization of the photoreceptor image potential, revealed low levels of image potentials and greater background suppression. As explained above, a CMB developer can be used in several systems, for example, a hybrid hopping system (HJD) or a development system without hybrid cleaning (HSD). In a HJD system, the development roller, better known as the donor roller, is driven by two development fields (potentials through an air gap). The first field is the ac jump field which is used for the generation of an organic pigment cloud and has a typical potential of 2.6 k volts from peak to peak at a frequency of 3.25 kHz. The second field is the CD development field which is used to control the amount of organic pigment mass revealed on the photoreceptor. Is It is desirable to eliminate the cd field and use the ac field duty cycle to control the mass of organic pigment to be developed on the photoreceptor. The HSD technology reveals the organic pigment via a conventional magnetic brush on the surface of a donor roller. A plurality of electrode wires is closely spaced from the donor roll with organic pigment in the developing zone. An AC voltage is applied to the wires to generate a cloud of organic pigment in the developing zone. This donor roller generally consists of a conductive core covered with a thin conductive, partially conductive layer, for example 50-200 μm. The magnetic brush roll is maintained at an electrical potential difference relative to the donor core to produce the necessary field for the development of the organic pigment. The layer of organic pigment on the donor roller is then disturbed by the electric field of a wire or a set of wires to produce and sustain a stirred cloud of organic pigment particles. The AC voltages typical of the wires in relation to the donor are 700-900 Vpp at frequencies of 5-15 kHz. These AC signals are often square waves, rather than pure sine waves. The organic pigment of the cloud is then revealed on the nearby photoreceptor by the fields created by a latent image.

The image-forming photoconducting devices are generally multi-layer photoreceptors comprising a substrate, on an optional conductive layer, an optional overcoating layer, an optional adhesive layer, a charge generating layer, a load transport layer, and a Optional overcoat layer. The organic pigment / developer described herein when used in a CMB developing system significantly reduces the wear rate of the surface of the photoreceptor. "Significantly" means that the wear rate decreases from about 22 nm / kcycles to a wear rate of about 10 nm / kcycles. "Kcycles" refers to 1000 revolutions of the photoreceptor. By reference, a typical photoreceptor that reaches 800 kilocycles, that is, 800,000 cycles, can produce from approximately 400,000 copies to approximately 600,000 copies. The photoreceptor wear rate described here is thus from about -0.004 μm / Kcycles to about -0.018 μm / Kcycles, from about -0.004 μm / Kcycles to about -0.0175 μm / Kcycles or from about -0.004 μm / Kcycles to approximately -0.017 μm / Kcycles. In this way, the developers of the present have a wear of the photoreceptor ranging from about -0.004 to about -0.018.

As a comparison, the wear rate of a photoreceptor used with known organic pigments can be greater than -0.018, such as from about -0.02 to about -0.03. Thus, the organic pigment described herein can decrease the wear rate of the photoreceptor by up to a factor of about 2.2, as a factor of about 1.3 to about 2.2. Illustrative examples of substrate layers selected for the photoreceptors of the present disclosure, and substrates which may be known substrates and which may be opaque or substantially transparent, comprise a layer of insulating material including inorganic or organic polymeric materials, such as the MYLAR ®, a commercially available polymer, MYLAR® containing titanium, a layer of an organic or inorganic material having a semiconductor surface layer, such as indium tin oxide, or aluminum arranged thereon, or a conductive material including aluminum, chrome, nickel, bronze or similar. The substrate may be flexible, continuous, or rigid, and may have a number of many different configurations, such as, for example, a plate, a cylindrical drum, a roll, an endless flexible band, and the like. In one embodiment, the substrate is in the form of a seamless flexible band. In some situations, it may be desirable to coat the back of the substrate, particularly when the substrate is a flexible organic polymeric material, an anti-wrinkle layer, for example, polycarbonate material commercially available as MAKROLON®. The thickness of the substrate layer depends on a number of factors, including the desired characteristics and economic considerations, thus, this layer can be of substantial thickness, for example of more than 3,000 microns, such as from about 3,000 to about 7,000 microns. of minimum thickness, as of at least about 50 microns, provided that there are no significant adverse effects on the limb. In embodiments, the thickness of this layer is from about 75 microns to about 300 microns. If a conductive layer is used, it is placed on the substrate. The term "envelope" as used herein in relation to many different types of layers, should be understood as being not limited to cases where the layers are continuous. Rather, the term refers to the relative placement of the layers and encompasses the inclusion of non-specific intermediate layers. Suitable materials for the conductive layer include, but are not limited to, aluminum, zirconium, niobium, tantalum, vanadium, hafnium, titanium, nickel, stainless steel, chromium, tungsten, molybdenum, copper and the like, and mixtures and alloys of the same. The thickness of the conductive layer is, in one embodiment, from about 20 angstroms to about 750 angstroms, and in another from about 50 angstroms to about 200 angstroms for an optimal combination of electrical conductivity, flexibility and light transmission. However, the conductive layer can, if desired, be opaque. The conductive layer can be applied by known coating techniques, such as solution coating, vapor deposition, and electrodeposition. In embodiments, an electrically conductive layer is applied by vacuum deposition. Other suitable methods can also be used. If a lower coating layer is used, it can be placed on the substrate, but below the load generating layer. The lower coating layer is sometimes referred to as the void blocking layer in the art. Lower coating layers suitable for use herein include, but are not limited to, polymers, such as polyvinyl butyral, epoxy resins, polyesters, polysiloxanes, polyamides, polyurethanes, and the like, nitrogen-containing siloxanes or nitrogen-containing titanium compounds, such as trimethoxysilyl propyl ethylene diamine, N-beta (aminoethyl) gamma-aminopropyl trimethoxy silane, 4-aminobenzene sulfonyl isopropyl titanate, di (dodecylbenzene sulfonyl) titanate, di (4-aminobenzoyl) isostearoyl isopropyl titanate, tri- (N-ethyl amino) isopropyl titanate, isopropyl triantranil titanate, tri (N, N-dimethyl) -ethyl amino) isopropyl titanate, titanium-4-amino benzene sulfonate oxyacetate, titanium 4-aminobenzoate isostearate oxyacetate, gamma-aminobutyl methyl dimethoxy silane, gamma-aminopropyl methyl dimethoxy silane, and gamma-aminopropyl trimethoxy silane, as described in U.S. Patent No. 4,338,387, U.S. Patent No. 4,286,033 and U.S. Patent No. 4,291,110. In embodiments, if a lower coating layer is employed, the lower coating layer may be a thick lower coating layer, as described in co-pending US Patent Application Publication No. 2006/0057480, which is incorporated herein by reference. reference in its entirety. The lower coating layer may comprise a metal component and a binder component. The metal component can be titanium dioxide or titanium oxide, and the binder component is a phenolic resin, polyester, polyvinyl butyral, polycarbonate, polystyrene-b-polyvinyl pyridine or polyvinyl formal. The metallic component may be present in the lower coating in an amount of about 20 to about 95 weight percent in the lower coating layer. The volumetric resistivity of the metal oxide can be from about 104 to about 1010 O-cm under a pressure of about 100 kg / cm2 at ambient conditions. If it is present, the lower coating layer can have a thickness of about 1 micrometer to about 30 micrometers. The lower coating layer can be applied as a coating by any suitable conventional technique such as spray, matrix coating, dip coating, stretch bar coating, etch coating, screen printing, air knife coating, reverse roller coating, Vacuum deposition, chemical treatment and the like. For convenience in obtaining the layers, the lower coating layer can be applied in the form of a diluted solution, with the solvent being removed after the deposition of the coating by conventional techniques such as vacuum, heating and the like. The drying of the deposited coating can be effected by any suitable technique such as oven drying, infrared radiation drying, air drying and the like. If a lower coating containing micron-sized particles is used, the formation of interference known as plywood is reduced. The term "plywood" refers to the formation of undesirable patterns in latent electrostatic images caused by multiple reflections during exposure of a loaded imaging member. Those patterns resemble plywood. In the manufacture of photosensitive imaging members, a charge generating layer is deposited and a load transport layer can be deposited on the surface of the substrate either in a laminate type configuration where the charge generating layer and Load transport are in different layers or in a single layer configuration where the load generating layer and the load transport layer are in the same layer together with a binder resin. The photoreceptors according to the present description can be prepared by applying the charge generating layer and a load transport layer. In embodiments, the charge generating layer and the load transport layer can be applied in any order. The charge generating layer is placed on the lower coating layer. If the lower coating layer is not used, the load generating layer is placed on the substrate. Any binder material can be used polymeric film former suitable as the matrix in the charge generating binder layer (photogenerator). Typical polymeric film forming materials include those described, for example, in U.S. Patent No. 3,121,006, the entire disclosure of which is incorporated herein by reference. Thus, typical organic polymer film-forming binders include thermoplastic and thermosetting resins, polycarbonates, polyesters, polyamides, polyurethanes, polystyrenes, polyarylethers, polyarylsulphones, polybutadienes, polysulfones, polyethersulfones, polyethylenes, polypropylenes, polyimides, polymethylpentenes, polyphenylene sulfides, polyvinyl acetate, polysiloxanes, polyacrylates, polyvinyl acetals, polyamides, polyimides, amino resins, phenylene oxide resins, terephthalic acid resins, phenoxy resins, epoxy resins, phenolic resins, polystyrene and acrylonitrile copolymers, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, acrylate copolymers, alkyd resins, cellulosic film formers, poly (amidimide), styrene-butadiene copolymers, vinylidene chloride-vinyl chloride copolymers, vinyl acetate-chloride copolymers, vinylidene, resi styrene-alkyd, polyvinylcarbazole, and the like. These polymers can be block copolymers, random or alternating. In embodiments, a load transport layer may be employed. The charge transport layer may comprise a charge transport molecule, typically a small molecule, dissolved or molecularly dispersed in an electrically inert film-forming polymer such as a polycarbonate. The term "dissolved" is defined herein as the former of a solution in which the molecules dissolve in the polymer to form a homogeneous phase. The term "molecularly dispersed" used herein is defined as a small carrier molecule dispersed in the polymer, with the small molecules dispersed in the polymer at a molecular scale. Any suitable small carrier or electrically active carrier molecule may be employed in the load transport layer of this disclosure. The term "carrier transport small molecule" is defined herein as a monomer that allows the photogenerated free charge in the generating layer to be transported through the transport layer. Typical charge transport molecules include, for example, compounds of pyrene, carbazole, hydrazone, oxazole, oxadiazole, pyrazoline, arylamine, arylmethane, benzidine, thiazole, stilbene and butadiene; pyrazolines such as 1-phenyl-3- (4'-diethylaminostiryl) -5- (4 '- diethyl phenyl) pyrazoline; diamines such as N, N '-diphenyl-N, N'-bis (3-methylphenyl) - (1,1'-biphenyl) -4,4'-diamine; hydrazones such as N-phenyl-N-methyl-3- (9-ethyl) carbacil hydrazone and 4-diethyl amino benzaldehyde-1,2-diphenyl hydrazone; oxadiazoles such as 2,5-bis (4-N, N '-diethylaminophenyl) -1,2,4-oxadiazole; poly-N-vinylcarbazole, poly-N-vinylcarbazole halide, polyvinyl pyrene, polyvinylanthracene, polyvinylacridine, a pyrene-formaldehyde resin, an ethylcarbazole-formaldehyde resin, a triphenylmethane polymer and polysilane, and the like. In embodiments, to avoid the up cycle in high performance machines, the load transport layer can be substantially free (less than about two percent) of triphenyl methane. As indicated above, the small electrically active small molecule charge transport compounds are dissolved or molecularly dispersed in the electrically inactive polymeric film forming materials. An exemplary small molecule charge transport compound that allows the injection of pigment voids into the load generating layer with high efficiency and that transports them through the load transport layer with very short transit times is N , N '-diphenyl-N, N' -bis (3-methylphenyl) - (1,1'-biphenyl) -4,4'-diamine. If desired, the cargo transport material in the cargo transport layer may comprise a carrier material. polymeric charge transport or a combination of a small molecule charge transport material and a polymeric charge transport material. In embodiments, the charge transport layer may contain an active aromatic diamine molecule, which permits charge transport, dissolved or molecularly dispersed in a film-forming binder. An exemplary charge transport layer is described in U.S. Patent No. 4,265,990, the entire disclosure of which is incorporated herein by reference. Any suitable electrically inactive resin binder that is also insoluble in a solvent such as the alcohol solvent used to apply the optional top coat layer can be employed in the load transport layer. Typical inactive resin binders include polycarbonate, polyester, polyarylate, polyacrylate, polyether, polysulfone resins and the like. Molecular weights may vary, for example, from about 20,000 to about 150,000. Exemplary binders include polycarbonates such as (4,4'-isopropylidene-diphenylene) carbonate (also known as bisphenol-A polycarbonate); polycarbonate; poly (4,4'-cyclohexylidindiphenylene) carbonate (known as bisphenol-Z polycarbonate); poly (4,4'-isopropylidene-3,3'-dimethyl-diphenyl) carbonate (also known as bisphenol-C polycarbonate); and similar. Any suitable charge transport polymer may also be used in the charge transport layer of this disclosure. The charge transport polymer should be insoluble in the solvent used to apply the top coat layer. These polymeric electrically active cargo transport materials should be able to withstand the injection of photogenerated voids of the charge generating material and be unable to allow the transport of those voids therethrough. Any suitable and conventional technique can be used to mix and subsequently apply the charge transport layer coating mixture to the charge generating layer. Typical application techniques include spraying, dip coating, roller coating, roll coating with wire, and the like. The drying of the deposited coating can be effected by any suitable conventional technique such as oven drying, infrared radiation drying, and air drying and the like. Generally, the thickness of the charge transport layer is from about 10 to about 50 micrometers, but thicknesses outside this range can also be used. A void transport layer shall be an insulator to the extent that the load electrostatics placed on the hole transport layer does not conduct in the absence of illumination at a sufficient speed to prevent the formation and retention of a latent electrostatic image on it. In general, the ratio of the thickness of a void transport layer to the load generating layers is typically maintained from about 2: 1 to 200: 1 and in some cases as large as 400: 1. Typically, a charge transport layer is substantially non-absorbent of visible light or radiation in the region of intended use but is electrically "active" such that it allows the injection of photogenerated voids of the photoconductive layer, i.e. the layer load generator, and allows those holes to be transported therethrough so as to selectively discharge a surface charge onto the surface of the active layer. Additionally, adhesive layers may be provided, if necessary, between any of the layers in the photoreceptor to ensure adhesion of any adjacent layers. Alternatively, or in addition, an adhesive material may be incorporated in one or both respective layers to be adhered. Those optional adhesive layers can obtain a thickness of about 0.001 microns to about 0.2 microns. This adhesive layer can be applied, for example, by dissolving the Adhesive material in a suitable solvent, hand applied, spray, dip coating, stretch bar coating, etch coating, screen printing, air knife coating, vacuum deposition, chemical treatment, roll coating, roller coating rolled with wire, and the like, and dried to remove the solvent. Suitable adhesives include, but are not limited to, film-forming polymers, such as polyester, DuPont 49,000 (available from EI DuPont de Nemours &Co.), Vitel PE-100 (available from Goodyear Tire and Rubber Co.), polyvinyl butyral, polyvinyl pyrrolidone, polyurethane, polymethyl methacrylate, and the like. Optionally, a top coat layer can also be used to improve the abrasion resistance. In some cases, a subsequent anti-crease coating may be applied to the opposite side of the photoreceptor to provide smoothness and / or abrasion resistance where a photoreceptor with network configuration is manufactured. Those topcoat and anti-wrinkle backcoat layers are well known in the art and may comprise thermoplastic organic polymers or inorganic polymers that are electrically insulative or slightly semiconductor. The top coatings are continuous and commercially have a thickness of less than about 10 microns.

Optionally, an anti-wrinkle backing layer may be used to balance the total forces of the layer or layers on the opposite side of the support substrate layer. An example of an anti-wrinkle support layer is described in U.S. Patent No. 4,654,284, the entire disclosure of which is incorporated herein by reference. A thickness of between about 70 and about 160 microns is a satisfactory range for flexible photoreceptors. To remove the organic pigments described herein from the photoconductive imaging member, the developing system may include a device for physically removing the organic pigments, for example, a cleaning blade or a cleaning brush. A flexible urethane type cleaning blade may be used to apply pressure against the photoconductive imaging member to prevent the organic pigment particles from passing therethrough. That flexible blade captures the organic pigment particles at the photoreceptor / blade interface and induces wear on the surface of the photoreceptor as it removes the organic pigment particles. In embodiments, suitable developers for use in CMB developing systems may include the organic emulsion / aggregate pigments described herein, which comprise a wax, a vitreous transition temperature (Tg) high latex, a gel latex and a colorant. Examples of waxes suitable for use herein include aliphatic waxes such as hydrocarbon waxes having from about 1 carbon atom to about 30 carbon atoms, such as from about 1 carbon atom to about 30 carbon atoms or from about 1 carbon atom to about 25 carbon atoms, polyethylene, polypropylene or mixtures thereof. More specific examples of waxes suitable for use herein include polypropylene and polyethylene waxes commercially available from Allied Chemical and Petrolite Corporation, wax emulsions available from Michaelman Inc. and the Daniels Products Company, EPOLENE N-15MR, commercially available from Eastman Chemical Products. , Inc. VISCOL dSO-P ^, a low weight average molecular weight polypropylene available from Sanyo Kasei KK, and similar materials. Commercially available polyethylene waxes are believed to have a molecular weight (Mw) of from about 1,000 to about 5,000, and commercially available polypropylene waxes are believed to have a molecular weight of from about 4,000 to about 10,000. Examples of functionalized waxes include amines, amides, for example AQUA SUPERSLIP 6550MR, SUPERSLIP 6530 ™ available from Micro Powder Inc., fluorinated waxes, eg POLYFLUO 19O101, POLYFLUO 200 ™, POLYFLUO 523XFMR, AQUA POLYFLUO 411 ™, AQUA POLYSILK 19 ™, and POLYSILK 14 ™ available from Micro Powder Inc, fluoride, amide waxes mixed, for example MICROSPERSION 19 ™ also available from Micro Powder Inc, imides, esters, quaternary amines, carboxylic acids or acrylic polymer emulsions, eg, JONCRYL 74 ™, 89 ™, 130, 537 ™, and 538 ™, all available from SC Johnson ax, and chlorinated polypropylenes and polyethylenes available from Allied Chemical and Petrolite Corporation and SC Johnson Wax. In embodiments, the wax comprises a wax in the form of a dispersion comprising, for example, a wax having a particle diameter of about 100 nanometers to about 500 nanometers, water and an anionic surfactant. In embodiments, the wax is included in amounts such as from about 2 to about 40 weight percent. The latitude of the wax around the formulation of the organic pigment particle of the central ring may be about 11 weight percent ± about 1 weight percent. In embodiments, the wax comprises polyethylene wax particles, such as POLYWAX 850, POLYWAX 750 and POLYWAX 655, commercially available from Baker Petrolite, having a particle diameter in the range of about 100 to about 500 nanometers.

The organic pigment particles described herein include a high Tg latex. For example, the high Tg latex comprises a latex comprising monomers, such as monomers of styrene, butyl acrylate and beta-carboxyethyl acrylate (beta-CEA) prepared, for example, by emulsion polymerization in the presence of an initiator, an agent chain transfer (CTA) and a surfactant. In place of beta-CEA, the high Tg latex can include any monomer containing carboxylic acid, such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid, maleic acid anhydride, citraconic anhydride, anhydride of itaconic acid, anhydride of alkenyl succinic acid, methyl ester of maleic acid, ethyl ester of maleic acid, butyl ester of maleic acid, methyl ester of citraconic acid, ethyl ester of citraconic acid, butyl ester of citraconic acid, methyl ester of itaconic acid, methyl ester of alkenyl succinic acid, methyl ester of fumaric acid, semi-ester of dibasic acid of partial saturation such as the methyl ester of mesaconic acid, dimethyl maleic acid, dibasic acid ester of partial saturation such as dimethyl fumaric acid, Acrylic, methacrylic acid, citraconic acid similar to alpha, cinnamonic acid, beta partial saturation acid, erotonic acid anhydride, cinnamonic acid anhydride, alkenyl malonic acid, a monomer which has an alkenyl glutaric acid and alkenyl adipic acid. In embodiments, the high Tg latex comprises styrene: butyl acrylate: beta-CEA where, for example, the high Tg latex monomers include from about 70 percent to about 90 weight percent styrene, about 10 percent by weight. weight percent to about 30 weight percent butyl acrylate, and from about 0.05 weight percent to about 10 weight percent beta-CEA. In embodiments, the organic pigment comprises high Tg latex in an amount of about 50 weight percent to about 95 weight percent of the total weight of the organic pigment described herein, such as 65 weight percent to about 80 weight percent total of the organic pigment described here. The latitude of high latex of Tg around about the central line particle formulation can be about 71 weight percent _ + about 4 weight percent. As used herein, "center line organic pigment particle formulation" refers to the ideal formulation of the organic pigment particles described herein. The term "latitude" refers to the possible variation in the formulation while still achieving the characteristics associated with the organic pigment particle formulation of the central line. The high Tg latex disclosed herein that is substantially free of crosslinking comprises a crosslinked density of less than about 0.1 percent, such as less than about 0.05. As used herein, "cross-linked density" refers to the mole fraction of monomer units which are crosslinking points. For example, in a system where 1 in 20 molecules is a divinylbenzene and 19 out of 20 molecules is a styrene, only 1 of 20 molecules would crosslink. Thus, in that system, the reticulated density would be 0.05. The initial Tg of high Tg latex can be from about 53 ° C to about 70 ° C, such as from about 53 ° C to about 67 ° C or from about 53 ° C to about 65 ° C, or about about 59 ° C. C. The weight average molecular weight (Mw) of high Tg latexes can be from about 2,000 to about 60,000, such as from about 30,000 to about 40,000 or about 35,000. The gel latex can be prepared from a high Tg latex, such as a latex comprising styrene monomers, butyl acrylate, beta-CEA, divinylbenzene, a surfactant and an initiator. In place of beta-CEA, the gel latex can include a monomer containing carboxylic acid as described above. The gel latex can be prepared by emulsion polymerization. In embodiments, the crosslinked density of the gel is from about 0.3 percent to about 40 percent, such as from about 0.3 percent to about 35 percent or from about 0.3 percent to about 30 percent of the crosslinked density. In embodiments, the organic pigment comprises gel latex in an amount of about 3 weight percent to about 30 weight percent of the total weight of the organic pigment described herein, such as 5 weight percent to about 15 weight of the total weight of the organic pigment described here. The latitude of the gel latex about the midline particle formulation can be about 10 weight percent + about 2 weight percent. The other latexes suitable for preparing the latex of High Tg and gel latex include styrene acrylates, styrene methacrylates, butadienes, isoprene, acrylonitrile, acrylic acid, methacrylic acid, beta-carboxy ethyl acrylate, polyesters, polymers known as poly (styrene-butadiene), poly ( methyl styrene-butadiene), poly (methacrylate) of methyl-butadiene), poly (ethyl-methacrylate-butadiene), poly (propyl-butadiene methacrylate), poly (butyl-butadiene methacrylate), poly (methyl-butadiene-acrylate), poly (ethyl-butadiene-acrylate), poly (propyl-butadiene acrylate), poly (butyl-butadiene-acrylate), poly (styrene-isoprene), poly (methyl styrene-isoprene), poly (methyl methacrylate-isoprene), poly (ethyl methacrylate-isoprene) ), poly (propyl-isoprene methacrylate), poly (butyl-isoprene methacrylate), poly (methyl-isoprene acrylate), poly (ethyl-isoprene-acrylate), poly (propyl-isoprene-acrylate), poly ( butyl-isoprene acrylate), poly (styrene-propyl acrylate), polystyrene-butyl acrylate), poly (styrene-butadiene-acrylic acid), poly (styrene-butadiene-methacrylic acid), poly (styrene-butyl acrylate) -acrylic acid), poly- (styrene-butyl acrylate-methacrylic acid), poly- (styrene-butyl acrylate-acrylonitrile), poly (styrene-acrylate) butyl acrylonitrile-acrylic acid ilate), and the like. In embodiments, the resin or polymer is a styrene / butyl acrylate / beta-carboxyethyl acrylate terpolymer. A suitable initiator for use in the production of both latex gel and high Tg latex can be, for example, sodium, potassium or ammonium persulfate and can be present with both of the initial crosslinking monomers and the initial non-crosslinking monomers in the interval about 0.1 weight percent to about 5 weight percent, such as from about 0.3 percent to about 4 weight percent of about 0.5 percent to about 3 weight percent of an initiator based on the total weight of the monomers In embodiments, the surfactant may be present in the range of from about 0.3 weight percent to about 10 weight percent, such as from about 0.5 weight percent to about 8 weight percent, or from about 0.7 to about 5.0 percent. by weight of the surfactant. Both latex gel and high Tg latex can be produced by similar methods. However, in the production of high Tg latex, no divinylbenzene or similar crosslinking agent is used. Examples of crosslinking agents suitable for producing the gel latex include divinylbenzene, divinylnaphthalene, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, diacrylate 1 , 6-hexanediol, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate # 400, dipropylene glycol diacrylate and polyoxyethylene (2) -2, 2-bis diacrylate ( 4-hydroxyphenyl) propane. Latex gel and high Tg latex can be produced by any method suitable. An example of a suitable method is described below? First, a surfactant solution is prepared by combining a surfactant with water. Suitable surfactants for use herein may be anionic, cationic or nonionic surfactants in effective amounts of, for example, from about 0.01 to about 15, or from about 0.01 to about 5 weight percent of the reaction mixture. Anionic surfactants include sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate, sodium dodecylnaphthalene sulfonate, dialkyl benzene alkyl, sulfate and sulphonates, abitic acid, available from Aldrich, NEOGEN R ™, NEOGEN SC ™ obtained from Kao, and the like. Examples of cationic surfactants include dialkyl benzene dialkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkyl benzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, benzalkonium chloride, cetyl pyridinium bromide, trimethyl ammonium bromides of Ci2, C15, C? 7, quaternized polyoxyethyl-alkylamines halide salts, dodecyl benzyl triethyl ammonium chloride, MIRAPOL and ALKAQUAT available from Alkaril Chemical Company, SANISOL (benzalkonium chloride) available from Kao Chemicals, SANISOL B-50 available from Kao Corp., which consists mainly of benzyl dimethyl alkoxide, and the like.

Examples of nonionic surfactants include polyvinyl alcohol, polyacrylic acid, metallose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octyphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, dialkylphenoxy poly (ethyleneoxy) ethanol, available from Rhone-Poulenac as IGEPAL CA-210 ™, IGEPAL CA-520 ™, IGEPAL CA-720 ™, IGEPAL CO- 890 ™, IGEPAL CO-720 ™, IGEPAL CO-290 ™, IGEPAL CA-210 ™, ANTAROX 890 ™ and ANTAROX 897 ™. In a separate vessel, an initiator solution is prepared. Examples of initiators for the preparation of the latex include water-soluble initiators, such as ammonium and potassium persulphates in suitable amounts, such as from about 0.1 to about 8 weight percent, and more specifically, in the range of about 0.2 to about 5 weight percent. The latex includes both the initial latex and the delayed latex aggregate where the delayed latex refers, for example, to the portion of latex that was added to the aggregates already formed in the size range of about 4 to about 6.5 μm, as described later. In another container, an emulsion of monomer by mixing styrene, butyl acrylate, beta-CEA, optionally divinylbenzene if gel latex is produced, and surfactant. In one embodiment, styrene, butyl acrylate, and / or beta-CEA are olefinic monomers. Once the preparation of the monomeric emulsion is complete, a small portion, eg, from about 0.5 to about 5 percent of the emulsion, is slowly fed to the reactor containing the surfactant solution. The initiator solution is then slowly added to the reactor. After about 15 to about 45 minutes, the remainder of the emulsion is added to the reactor. After about 1 to about 2 hours, but before all the emulsion is added to the reactor, 1-dodecantiol or carbon tetrabromide is added. (chain transfer agents that control / limit the length of the polymer chains) to the emulsion. In embodiments, the charge transfer agent can be used in effective amounts of, for example, from about 0.5 weight percent to about 15 weight percent of the initial monomers, such as from about 0.1 weight percent to about 13 weight percent. percent by weight or from about 0.1 weight percent to about 10 weight percent of the initial monomers. The emulsion continues to be added to the reactor.

The monomers can be polymerized under low feed conditions as referenced in U.S. Patent No. 6,447,974, herein incorporated by reference in its entirety, to provide latex resin particles having a diameter in the range of about 20 nanometers to about 500 nanometers, from about 75 nanometers to about 400 nanometers or from about 100 to about 300 nanometers. The dyes or pigments include pigments, dyes, mixtures of pigments and dyes, mixtures of pigments, mixtures of dyes, and the like. In embodiments, the colorant comprises a pigment, a dye, a mixture thereof, carbon black, magnetite, black, cyan, magenta, yellow, red, green, blue, brown, mixtures thereof in an amount of about 1. percent by weight up to about 25 weight percent based on the total weight of the organic pigment composition, such as from about 2 weight percent to about 20 weight percent or about 5 weight percent to about 15 weight percent percent by weight based on the total weight of the organic pigment composition. In embodiments, the latitude of the dye around about a central line particle formulation is about 8 weight percent ± about 0.5 weight percent based on the total weight of the organic pigment composition. It should be understood that the other useful colorants will be readily apparent to one skilled in the art on the basis of the description herein. In general, useful dyes include Paliogen Violet 5100 and 5890 (BASF), Normandy Magenta RD-2400 (Paul Uhlrich), Permanent Violet VT2645 (Paul Uhlrich), Green Heliogen L8730 (BASF), Green Argil XP- 111-S (Paul Uhlrich), Bright Green Organic Pigment GR 0991 (Paul Uhlrich), Scarlet of litol D3700 (BASF), Red of Toluidine (Aldrich), Scarlet for Red Termoplast NSD (Aldrich), Organic Pigment of Litol Rubine (Paul Uhlrich), Scarlet of Litol 4440, NBD 3700 (BASF), Red C of Bon (Dominion Color), Royal Bright Red RD-8192 (Paul Uhlrich), Rose of Oracet RF (Ciba Geigy), Red of Paliogen 3340 and 3871K (BASF), Scarlet Litol Fast L4300 (BASF), Blue Heliogen D6840, D7080, K7090, K6910 and L7020 (BASF), Blue Sudan OS (BASF), Blue Neopen FF4012 (BASF), Blue PV Fast B2G01 (American Hoechst), Blue of Irgalite BCA (Ciba Geigy), Blue of Paliogen 6470 (BASF), Sudan II, III and IV (Matheson, Coleman, Bell), Orange of Sudan (Aldrich), Orange of Sudan 220 (BASF), Orange of Paliogen 3040 ( BASF), Orange Orto OR 2673 (Paul Uhlrich), Yellow of Paliogen 152 and 1560 (BASF), Yellow of Litol Fast 0991K (BASF), Yellow of Paliotol 1840 (BASF), Yellow by Novaperm FGL (Hoechst), Yellow by Permanerit YE 0305 (Paul Uhlrich), Yellow by Lumogen D0790 (BASF), Suco-Gelb 1250 (BASF), Suco-Yellow D1355 (BASF), Yellow by Suco Fast D1165, D1355 and D1351 (BASF), Rosa de Hostaperm E (Hoechst), Pink of Fanal D4830 (BASF), Magenta of Cinquasia (DuPont), Black of Paliogen L9984 9BASF), Pigmento Negro K801 (BASF) and particularly black smoke such as REGAL 330 (Cabot), Smoke Black 5250 and 5750 (Columbian Chemicals), and the like or mixtures thereof. Additional useful colorants include pigments in water-based dispersions, such as those commercially available from Sun Chemical, for example, SUNSPERSE BHD 6011X (Blue Type 15), SUNSPERSE BHD 9312X (Pigment Blue 15 74160), SUNSPERSE BHD 6000X (Pigment Blue 15: 3 74160), SUNSPERSE GHD 9600X and GHD 6004X (Pigment Green 7 74260), SUNSPERSE QHD 6040X (Pigment Red 122 73915), SUNSPERSE RHD 9668X (Pigment Red 185 12516 ), SUNSPERSE RHD 9365X and 9504X (Pigment Red 57 15850: 1, SUNSPERSE YHD 6005X (Pigment Yellow 83 21108), FLEXIVERSE YFD 4249 (Pigment Yellow 17 21105), SUNSPERSE YHD 6020X and 6045X (Pigment Yellow 74 11741), SUNSPERSE YHD 600X and 9604X (Pigment Yellow 14 21095), FLEXIVERSE LFD 4343 and LFD 9736 (Pigment Black 7 77226) and the like or mixtures thereof Other useful water-based dye dispersions include those commercially available from Clariant, e.g.

Yellow GR HOSTAFINE, Black T and Black TS HOSTAFINE, Blue B2G HOSTAFINE, HOSTAFINE Rubine F6B and dry magenta pigment such as Magenta Organic Pigment 6BVP2213 and Magenta Organic Pigment E02 which can be dispersed in water and / or surfactant before use. Other useful colorants include, for example, magnetites, such as Mobay magnetites M08029, M08960; Columbian magnetites, MAPICO BLACKS and surface treated magnetites; Pfizer magnetites CB4799, CB5300, CB5600, MCX6369; magnetite from Bayer, BAYFERROX 8600, 8610; Northern Pigments magnetites, NP-604, NP-608; magnets of Magnox TMB-100 or TMB-104; and similar or mixtures thereof. Additional specific examples of pigments include phthalocyanine HELIOGEN BLUE L6900, D6840, D7080, D7020, PYLAM OIL BLUE, PYLAM OIL YELLOW, PIGMENT BLUE 1 available from Paul Uhlrich & Company, Inc., PIGMENT VIOLET 1, PIGMENT RED 48, LEMON CHROME YELLOW DCC 1026, E.D. TOLUIDINE RED and BON RED C available from Dominion Color Corporation, Ltd., Toronto, Ontario, NOVAPERM YELLOW FGL, HOSTAPERM PINK E from Hoechst, and MAGENTA CINQUASIA available from E.I. DuPont de Nemours & Company, and the like. Examples of magnetites include, for example, dye of quinacridone and anthraquinone substituted with 2,9-dimethyl identified in the Color Index as Cl 60710, Dispersed Red Cl 15, diazo dye identified in the Color Index as Cl 26050, Red Solvent Cl 19, and the like or mixtures thereof. Illustrative examples of cyans include tetra (octadecylsulfonamide) phthalocyanine copper, phthalocyanine pigment x-copper listed in the Color Index as CI74160, Pigment Blue Cl, and Anthratren Blue identified in the Color Index as DI 69810, Special Blue X-2137, and the like or mixtures thereof. Illustrative examples of Yellow that may be selected include the diarylide Yellow 3, 3-dichlorobenzide acetoacetanilides, monoazo pigment identified in the Color Index as Cl 12700, Yellow Solvent Cl 16, a nitrophenyl amin sulfonamide identified in the Color Index as Yellow of Foron SE / GLN, Dispersed Cl Yellow Cl 33 2, 5-dimethoxy-4-sulfonanilide phenylazo-4 'chloro-2,4-dimethoxy acetoacetanilide, and Permanent Yellow FGL. The colored magnetites, as mixtures of MAPICO BLACK and cyan components can also be selected as pigments. The organic pigment particles can be produced by any known emulsion / aggregation process. An example of such a process suitable for use herein includes forming a mixture of high Tg latex, gel latex, wax and dye, and deionized water in a container. The mixture is then stirred using a homogenizer until homogenized and then transferred to a reactor where the homogenized mixture is heated to a temperature of, example, about 50 ° C and is maintained at that temperature for a period of time to allow the aggregation of the organic pigment particles to the desired size. Once the desired size of the added organic pigment particles is achieved, the pH of the mixture is adjusted to inhibit further aggregation of the organic pigment. The organic pigment particles are further heated to a temperature of, for example, about 90 ° C and the pH is decreased to allow the particles to coalesce and spherodize. The heater is then turned off and the reactor mixture is allowed to cool to room temperature, at which point the added and coalesced organic pigment particles are recovered and optionally washed and dried. Diluted solutions of flocculating or aggregating agents can be used to optimize particle aggregation time with as little formation as possible of large, contaminating particles. Examples of flocculating or aggregating agents may include polyaluminium chloride (PAC), dialkyl benzealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkylbenzyl dimethyl ammonium bromide, benzalkonium chloride, cetylpyridinium bromide, bromides of trimethyl ammonium of C? 2, C? 5, C? 7 / quaternized polyoxy ethylalkylamine halide salts, dodecylbenzyl chloride triethylammonium, MIRAPOL ™ and ALKAQUAT ™ (available from Alkaril Chemical Company), SANIZOL ™ (benzalkonium chloride) (available from Kao Chemicals), and the like, and mixtures thereof. In embodiments, the flocculating or aggregating agents can be used in an amount from about 0.01 weight percent to about 10 weight percent of the organic pigment composition, such as from about 0.02 weight percent to about 5 weight percent or from about 0.05 weight percent to about 2 weight percent. For example, the latitude of the flocculating or aggregating agents around about a central line particle formulation is about 0.17 weight percent ± about 0.02 weight percent based on the total weight of the organic pigment composition. The organic emulsion aggregation pigment described herein produces an organic pigment particle that is more slippery than other types of organic pigments. The level of wax incorporated into the organic pigment particles may be higher than in other known organic pigment particles, and it is believed that the increase in the amount of wax in the organic pigment particles increases the ability of the organic pigment particles to lubricate the photoreceptor. In addition, organic pigment particles described herein have a higher level of transfer of organic pigment particles from the photoreceptor to the paper resulting in transfer efficiency levels of more than about 90 percent, such as in the range of from about 95 percent to about 99.9 percent in weight transfer efficiency. Because the organic pigment described here is a better lubricant with better transfer efficiency, there is less organic pigment remaining on the photoreceptor during the cleaning process. Thus, the rate of wear of the photoreceptor surface by the friction generated between the cleaning blade and the photoreceptor when the residual organic pigment is removed from the surface can be reduced. Most photoreceptor wear occurs at the interface where the cleaning blade removes the organic pigment particles from the surface of the photoreceptor. The size of the organic pigment particles formed can be from about 3 μm to about 8 μm, as an organic pigment particle size from about 4.5 μm to about 7 μm or from about 5 μm to about 6 μm. Circularity can be determined using the Malvern Sysmex Flow Particle Imaging Analyzer FPIA-2100 known. Circularity is a measure of the closeness of particles to a perfect sphere. A circularity of 1.0 identifies a particle that has the shape of a perfect circular sphere. The organic pigment particles described herein can have a circularity of from about 0.9 to about 1.0, such as from about 0.93 to about 1.0 or from about 0.95 to about 1.0. The organic pigment particles preferably have a size such that the upper geometric standard deviation (GSDv) in volume for (D84 / D50) is in the range of about 1.15 to about 1.25, such as about 1.18 to about 1.23. The particle diameters at which a cumulative percentage of 50% of the total organic pigment particles is reached is defined as the volume D50, which is from about 5.45 to about 5.88, and from about 5.47 to about 5.85. The particle diameter at which a cumulative percentage of 84% is reached is defined as volume D84. Those aforementioned GSDv volume average particle size distribution indices can be expressed using D50 and D84 in the cumulative distribution, where the volume average particle size distribution index GSDv is expressed as (volume D84 / volume D50) . The value of Higher GSDv for the organic pigment particles indicates that the organic pigment particles were produced to have a very narrow particle size distribution. The organic pigment mass developed per unit area (TMA) suitable for printed images of the organic pigment described herein may be in the range of about 0.35 mg / cm2 to about 0.55 mg / cm2, as of about 0.4 mg / cm2 to about 0.5 mg / cm2 or from approximately 0.43 mg / cm2 to approximately 0.47 mg / cm2. It may also be desirable to control the particle size of the organic pigment and limit the amount of both fine and coarse particles in the organic pigment. The organic pigment particles can have a very narrow particle size distribution with a geometric standard deviation of the numerical ratio (GSDn), lower, which is expressed as (number D50 / number D16), from about 1.20 to about 1.30, from about 1.22 to about 1.29. The organic pigment particles described herein are described in co-pending U.S. Patent Application No. 11 / 610,291, filed December 13, 2006, which is incorporated herein by reference in its entirety. The organic pigment particles described herein may include external additives. These external additives they can be additives that are associated with the surface of the organic pigment particles. In the present description, external additives include at least one of silicon dioxide or silica (Si0), or titanium or titanium dioxide (Ti02). In general, the silica is applied to the surface of the organic pigment for the flow of the organic pigment, improving the triboelectric characteristics, mixing control, better development and transfer stability and higher blocking temperature of the organic pigment. Ti02 is applied to improve the stability to relative humidity (RH), triboelectric control and better development and transfer stability. In embodiments, the external additive package includes both silica and titania. The Si02 and Ti0 can have a primary particle size of less than 200 nm. The silica can have a primary particle size in the range of about 5 to about 200 nm. The titania can have a primary particle size in the range of about 5 to about 50 nm. Of course, larger sized particles may also be used, if desired, for example, up to about 500 nm. It was found that Ti02 is especially useful to maintain development and transfer over a wide range of coverage of area and work period. Si02 and Ti02 can be applied to the surface of the organic pigment with the total coverage of the organic pigment ranging from approximately 50 percent to approximately 200 percent of the surface area coverage (SAC). Another metric related to the quantity and size of the additives is "SAC x size" ((percentage of coverage of the surface area) (the primary particle size of the additive in nanometers)), for which the additives may have an SAC interval x total size from about 1000 to about 4000. In embodiments, the added Si02 can be surface treated with a polydimethylsiloxane, such as RY50 available from Nippon Aerosil. Other suitable treated fumed silicas are commercially available from TS530 of Cabot Corporation, Cab-O-Sil Division. The titania can be treated or not treated. Untreated titanium dioxide is available as P25 from Degussa. The titanium dioxide can be surface treated, for example with decyl silane which is commercially available as MT3103, or as SMT5103, both available from Tayca Corporation. At least two external metal stearate additives selected from the group consisting of zinc stearate, calcium stearate, aluminum stearate and magnesium stearate may also be present on the organic pigments. Metal stearates provide lubricating properties. Due to their lubricating nature, metal stearates also provide a triboelectric improvement. In addition, metal stearates provide a higher load and stability in loading to the organic pigment by increasing the number of contacts between the organic pigment and carrier particles. A commercially available metal stearate is zinc stearate, which has a particle size such as 100% of the materials that pass through a 325 mesh screen, known as ZINC L ™ STEARATE produced by Ferro Corporation, Division of Polymeric additives. Other commercially available zinc stearates, such as those available from Synthetic Products. No single metal stearate can provide all the desired performance attributes, which often lead to some exchange in performance. For example, U.S. Patent No. 6,416,916 teaches that higher amounts of zinc stearate result in the occurrence of image depletion defects appearing in solid area images, particularly during prolonged print jobs. Thus, the amount of zinc stearate in that example should be limited to less than 0.1 percent loading in the organic pigment. It has been found that if at least two stearates metal are part of the external additives, several benefits are achieved in the CMB system. In particular, in the HSD developing system, by adding more than one metal stearate as an external additive selected from the group consisting of zinc stearate, calcium stearate, aluminum stearate and magnesium stearate to the organic pigment, an excellent combination of desired performance attributes, such as load level, load stability, HR sensitivity, mixing, load-step, load distribution widths, and developer conductivity. In embodiments, external additives may include aluminum stearate and calcium stearate. The metal stearates may be present in the organic pigment particles in an amount from about 0.025 percent to about 5.0 weight percent of the organic pigment particles, such as from about 0.05 weight percent to about 3 weight percent of the organic pigment particles. When two metal stearates are used, the ratio of the two metal stearates can range from about 4: 1 to about 1: 1, about 2.1 to about 1: 1 or about 1: 1. Illustrative examples of carrier particles or carriers can be selected to be mixed with the organic pigment composition prepared in accordance with the present disclosure includes those particles that are capable of triboelectrically obtaining a charge of polarity opposite to that of the organic pigment particles. Illustrative examples of suitable carrier particles include granular zirconia, granular silicon, glass, steel, nickel, ferrites, iron ferrites, silicon oxide, and the like. Additionally, carrier particles, nickel and beryllium particles can be selected as described in U.S. Patent No. 3,847,604, the entire disclosure of which is hereby incorporated by reference in its entirety, comprised of nodular nickel carrier beads, characterized by surfaces of cavities and recurring projections that therefore provide particles with a relatively large external area. Other supports or carriers are described in U.S. Patent Nos. 4,937,166 and 4,935,326, the descriptions of which are hereby incorporated herein by reference. In embodiments, the carrier or support may be comprised of commercially available atomized steel from, for example, Hoeganaes Corporation. The selected carrier particles or carriers can be used with or without coating, the coating generally being of fluoropolymers, such as polyvinylidene fluoride resins, terpolymers of styrene, methyl methacrylate, a silane, such as triethoxy silane, tetrafluoroethylenes, other known coatings and the like. In another embodiment, the carrier core is partially coated with a polymethyl methacrylate (PMMA) polymer having a weight average molecular weight of 300,000 to 350,000 commercially available from Soken. PMMA is an electropositive polymer in which the polymer will generally impart a negative charge on the organic pigment on which it is in contact. The PMMA can optionally be copolymerized with any desired comonomer, as long as the resulting copolymer retains a suitable particle size. Suitable comonomers may include monoalkyl, or dialkylamines, such as di-ethylaminoethyl methacrylate, diethylaminoethyl methacrylate, diisopropylaminoethyl methacrylate, or t-butylaminoethyl methacrylate, and the like. In yet another embodiment, the polymeric coating of the core of the carrier or support may be comprised of PMMA applied in dry powder form and having an average particle size of less than 1 micrometer, such as less than 0.5 micrometer, which is applied ( melted and fused) to the support core or carrier at higher temperatures of the order of 220 ° C to 260 ° C. Temperatures above 260 ° C may adversely degrade PMMA. The ability to refine the triboelectric properties of the carrier or carriers and the developers herein is provided by the temperature at which the coating of the carrier or carrier is applied, resulting in higher temperatures increasing the triboelectric characteristics to a point beyond the which the increase in temperature acts to degrade the polymeric coating and in this way lower triboelectric characteristics. The ratio of organic pigment to support in the developer described herein may be from about 3.0 to about 5.5, such as from about 4.0 to about 5.0 or about 4.5. The organic pigments and developers described herein can be used in xerographic devices having a variety of process speeds. These devices can have process speeds of approximately 170 mm / sec to approximately 400 mm / sec. about 180 mm / sec to about 390 mm / sec or about 190 mm / sec to about 380 mm / sec. The printing speed of xerographic devices can be from about 20 ppm to about 110 ppm, such as from about 25 ppm to about 100 ppm or about 30 ppm up to approximately 90 ppm. In embodiments, the printing speed can be about 35 ppm, about 38 ppm, about 45 ppm, about 55 ppm, about 75 ppm or about 87 ppm. The embodiments described above will now be better illustrated by means of the following examples.

Example 1: Preparation of Organic Pigment Particles with 10.5% Polywax 655 EA particles were prepared by mixing together approximately 278.5 kilograms of High Tg Latex having a solids loading of approximately 41.57 weight percent, approximately 92.41 kilograms of emulsion POLYWAX 655® wax having a solids loading of about 30.28 weight percent, about 130.55 kilograms of a black pigment dispersion Cavitron PD-K125 (Regal 330) having a solids loading of about 17.08 weight percent, approximately 104.0 kilograms of a Latex Gel having a solids content of about 25 weight percent with about 831.7 kilograms of deionized water in a vessel while stirring using an IKA Ultra Turrax® T50 homogenizer operating at approximately 4,000 rpm. After 30 minutes of homogenization, the slow controlled addition of approximately 44.2 was made kilograms of a flocculent mixture containing approximately 4.42 kilograms of polyaluminium chloride mixture and approximately 39.78 kilograms of nitric acid solution approximately 0.02 molar. The temperature of the reactor jacket was set at approximately 57 ° C and the particles were added to an objective size of approximately 4.8 microns as measured with a Multisizer. After reaching approximately 4.8 microns, additional amounts of approximately 179.3 kilograms of High Tg latex were added and the particles grew to the target particle size from about 5.85 to about 5.90 microns. The particle size was frozen by adjusting the pH of the reactor mixture to about 6.0 with sodium hydroxide solution to about 1 molar. Subsequently, the reactor mixture was heated to about 0.375 ° C per minute at a temperature of about 85 ° C, followed by adjusting the pH of the reactor mixture to about 3.9 with approximately 0.3 M nitric acid solution. The reaction was then brought to about 96 ° C to about 0.375 ° C per minute. At the beginning of the coalescence of the particles, the pH was verified but it was not adjusted. The shape of the particle was verified by measuring the circularity of the particle using the Sysmex FPIA form analyzer. Once the target circularity of approximately 0.958 was reached, the pH was adjusted to about 7.0 with sodium hydroxide solution at about 1 percent. The particles continued to coalesce for a total of about 2.5 hours at about 96 ° C. The particles were cooled to approximately 63 ° C. At about 63 ° C, the suspension was treated with sodium hydroxide solution at about 4 percent at a pH of about 10 for about 20 minutes followed by cooling to about room temperature. The organic pigment in this mixture comprises about 71.5 percent styrene / acrylate polymer, about 8 percent Regal 330 pigment, about 10.5 weight percent Polywax 655, and about 10 weight percent Gel Latex. The particles were washed 3 times after the removal of the mother liquor consisting of a wash with deionized water at about room temperature, a wash carried out at a pH of about 4.0 to about 40 ° C, and finally the last wash with deionized water at approximately room temperature. The amount of approximately 0.3 molar nitric acid used for washing at pH 4 was about 30 grams per kilogram of particles.

After drying the particles in an Aljet dryer, the final average particle size D50 = 5.95 microns, GSDv of about 1.20, GSDn of about 1.25, fine percent (<4.0 microns) of about 12.8% and particle circularity of approximately 0.962. The package of surface additive mixed on the particles consisted of about 0.74 weight percent X-24 which is a type of silica (silica A, about 1.11 weight percent titanium dioxide and about 1.71 weight percent of silica type B. This organic pigment was then mixed with a support to produce the developer that was used to generate impressions and to determine the wear rate of the photoreceptor with organic pigment EA.

Example 2: Preparation of Organic Pigment Particles B with 9% Polywax 725 The EA particles were prepared by mixing together about 166.2 kilograms of high Tg Latex having a solids loading of 41.57 weight percent, 45.70 kilograms of an emulsion of POLYWAX 725® wax having a solids loading of approximately 30.28 weight percent, approximately 75.32 kilograms of black pigment dispersion CAVITRON PD-K125 (Regal 330) which had a solids loading of approximately 17.08 weight percent, 60.0 kilograms of Gel Latex abpit having a solids content of approximately 25 weight percent with approximately 481.9 kilograms of deionized water in a container while stirring using a homogenizer IKA Ultra Turrax® T50 operating at approximately 4,000 rpm. After about 30 minutes of homogenization, the slow controlled addition of approximately 25.5 kilograms of a flocculent mixture containing approximately 2.55 kilograms of polyaluminium chloride mixture and approximately 22.95 kilograms of nitric acid solution at approximately 0.02 molar was made. The temperature of the reactor jacket was set at about 57 ° C and the particles were added to a smaller size of about .8 microns. After reaching approximately 4.8 microns, approximately 103.44 additional kilograms of High Tg Latex were added and the particles grew to the target particle size from about 5.85 to about 5.9 microns. The particle size was frozen by adjusting the pH of the reactor mixture to about 6.0 with sodium hydroxide solution to about 1 molar. Subsequently, the reactor mixture was heated to approximately 0.375 ° C per minute at a temperature of about 85 ° C, followed by adjusting the pH of the reactor mixture to about 3.9 with nitric acid solution at about 0.3 M. The reaction mixture was then brought to about 96 ° C to about 0.375 ° C. minute. At the beginning of the coalescence of the particles, the pH was verified but it was not adjusted. The particle shape was verified by measuring the particle circularity using the Sysmex FPIA form analyzer. Once the target circularity of 0.958 was reached, the pH was adjusted to about 7.0 with sodium hydroxide solution at about 1 percent. The coalescence of the particles continued for a total of about 5 hours at about 96 ° C. The particles were cooled to approximately 63 ° C. At about 63 ° C, the suspension was treated with sodium hydroxide solution at about 4 percent at a pH of about 10 for about 20 minutes followed by cooling to about room temperature. The organic pigment in this mixture comprised about 73 percent styrene / acrylate polymer, about 8 percent Regal 330 pigment, about 9 percent by weight of POLYWAX 725 and about 10 percent by weight of Gel Latex.

The particles were washed approximately 5 times after the removal of the mother liquor consisting of about 3 washes with deionized water at about room temperature, a wash was carried out at a pH of about 4.0 to about 40 ° C, and finally the last wash with deionized water at about room temperature. The amount of approximately 0.3 molar nitric acid used for washing pH 4 was about 20 grams per kilogram of particles. After drying the particles in an Aljet dryer, the final average particle size D50 = 5.60 microns, GSDv of about 1.21, GSDn of about 1.26, fine percent (<4.0 microns) of about 19.0 percent and particle circularity of approximately 0.956. The package of surface additive mixed on the particles consisted of about 0.74 weight percent silica X-24 type A, about 1.11 weight percent titanium dioxide and about 1.71 weight percent silica type B. This organic pigment it was then mixed with a support to produce the developer that was used to generate impressions in the test and to determine the wear rate of the photoreceptor with organic pigment EA.

Results As summarized in Table 1, the reduction in the surface wear rate of the photoreceptor when organic pigments of small-sized EA (approximately 5.7 microns) are replaced by the organic pigment much larger conventional (approximately 8.9 micrometers). With organic pigment EA the reduction in CTL thickness decreased significantly anywhere from 1.3 times at slower printing speeds to 2.2 times at faster speeds. For a photoreceptor with a target life of more than 400,000 impressions, a decrease in wear of 2 times will allow the life of the photoreceptor to increase 2 times. In this way, the prolongation of the life of the photoreceptor has an impact on the total costs. Another benefit of reducing the wear of the photoconductive surfaces is a more stable image quality since the fixed xerographic points are less sensitive to the effects of aging. It will be appreciated that several of the features and functions described above and others, or alternatives thereof, may be desirably combined in many other different systems or applications. Also, they may be produced, subsequently by those skilled in the art, alternatives, modifications, variations or improvements not contemplated or not currently anticipated, and are also intended to be encompassed by the following claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (22)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. An electrophotographic image forming apparatus, characterized in that it comprises a photoreceptor, a conductive magnetic brush developing system, and a housing in association with the conductive magnetic brush developing system for a developer comprising an organic pigment composition that has emulsion / aggregate organic pigment particles comprising a gel latex, a high Tg latex, a wax and a dye, where the gel latex is present in an amount of about 3 weight percent to about 30 percent by weight of the organic pigment composition, the high Tg latex is present in an amount of about 50 weight percent to about 95 weight percent of the organic pigment composition, the wax is present in an amount of about 2. percent by weight up to about 40 weight percent of the organic pigment composition , and the dye is present in an amount of about 1 weight percent to about 25 weight percent of the organic pigment composition.
2. 2. The electrophotographic image forming apparatus, according to claim 1, characterized in that a latitude of the gel latex about an organic pigment particle formulation of the centerline is about 10 percent by weight ± about 2 percent by weight, a latitude of high Tg latex of about a midline particle formulation is about 71 weight percent ± about 4 weight percent, a latitude of the wax about one particle formulation of organic pigment of the center line is about 11 weight percent ± about 1 weight percent, and a latitude of the dye about about an organic pigment particle formulation of the center line is about 8 weight percent ± about 0.5 percent by weight.
3. 3. The electrophotographic image forming apparatus according to claim 1, characterized in that the organic pigment composition further includes a flocculant, and where a latitude of the flocculant about a particle formulation of the centerline is about 0.17 percent. by weight ± approximately 0.02 percent by weight.
4. 4. The image forming apparatus electrophotographic, according to claim 1, characterized in that the crosslinked density of the gel latex is from about 0.3 to about 40, and a cross-linked density of the high Tg latex is at least about 0.1.
5. 5. The electrophotographic image forming apparatus according to claim 1, characterized in that the apparatus further includes a cleaning device for removing the organic pigment particles from the surface of the photoreceptor.
6. 6. The electrophotographic image forming apparatus according to claim 5, characterized in that the cleaning device is a cleaning blade.
7. The electrophotographic image forming apparatus, according to claim 1, characterized in that the photoreceptor has a wear rate of about -0.004 μm / Kcycles to about -0.018 μm / Kcycles.
8. The electrophotographic image forming apparatus, according to claim 1, characterized in that the organic pigment particles provide a better wear rate of about 1.3 to about 2.2.
9. 9. The image forming apparatus electrophotographic, according to claim 1, characterized in that the organic pigment particles include at least one external additive.
10. 10. The electrophotographic image forming apparatus, according to claim 9, characterized in that at least one external additive comprises a metal.
11. 11. The electrophotographic image forming apparatus, according to claim 1, characterized in that the developer further comprises a support or carrier.
12. 12. A developer, characterized in that it comprises a support or carrier and an organic emulsion / aggregation pigment, wherein the organic pigment comprises a latex gel, a latex of high Tg, a wax, and a dye, where the latex gel is present in an amount of about 3 weight percent to about 30 weight percent of the organic pigment, the high Tg latex is present in an amount of about 50 weight percent to about 95 weight percent of the organic pigment, the wax is present in an amount of about 2 weight percent to about 40 weight percent of the organic pigment, and the dye is present in an amount of about 1 weight percent to about 25 weight percent of the organic pigment, and where the developer is able to reduce photoreceptor wear in a developing system of a conductive magnetic brush.
13. The developer according to claim 12, characterized in that a latitude of the gel latex is about an organic pigment particle formulation of the centerlines of about 10 weight percent ± about 2 weight percent.
14. The developer according to claim 12, characterized in that a latitude of the high Tg latex around about a central line particle formulation is about 71 weight percent ± about 4 weight percent.
15. The developer according to claim 12, characterized in that the latitude of the wax around about one formulation of organic pigment particles of the center line is about 11 weight percent ± about 1 weight percent.
16. 16. The developer according to claim 12, characterized in that a latitude of the dye about an organic pigment particle formulation of the center line is about 8 weight percent ± about 0.5 percent in weight.
17. 17. The developer according to claim 12, characterized in that a cross-linked density of the gel latex is from about 0.3 weight percent to about 40, and a cross-linked density of the high Tg latex is less about 0.1.
18. 18. A method for printing an image based on organic pigment, characterized in that it comprises: charging a photoreceptor to a uniform potential, exposing the surface of the photoreceptor charged to a light image to register a latent electrostatic image on the surface of the photoreceptor, reveal the image latent electrostatics by placing the developer in contact with the latent electrostatic image to expose an image, transferring the image to a substrate to form an image based on organic pigment, and fusing the image based on organic pigment to the substrate, where the developer comprises an organic pigment of emulsion / aggregation having a gel latex, a high Tg latex, a wax, and a dye, and where the residual organic pigment is removed from the surface of the photoreceptor with a cleaning device, and where the photoreceptor wear rate is about -0.004 μm / Kcycles to about -0.018 μm / Kcycles.
19. 19. The method according to claim 18, characterized in that the developer further comprises a support or carrier.
20. The method according to claim 18, characterized in that the development occurs with a conductive magnetic brush developing system.
21. 21. The method according to the claim 18, characterized in that the cleaning device is a cleaning blade.
22. 22. A developer, characterized in that it comprises a support or carrier and an organic pigment, wherein the developer has a photoreceptor attrition rate of about

    0. 004 μm / Kcycles to approximately -0.018 μm / Kcycles.