EP0302686B1 - Compositions de développateur - Google Patents

Compositions de développateur Download PDF

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Publication number
EP0302686B1
EP0302686B1 EP19880307085 EP88307085A EP0302686B1 EP 0302686 B1 EP0302686 B1 EP 0302686B1 EP 19880307085 EP19880307085 EP 19880307085 EP 88307085 A EP88307085 A EP 88307085A EP 0302686 B1 EP0302686 B1 EP 0302686B1
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EP
European Patent Office
Prior art keywords
developer
weight
percent
toner
particles
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EP19880307085
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German (de)
English (en)
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EP0302686A3 (en
EP0302686A2 (fr
Inventor
John R. Laing
Hui Chang
Richard D. Manca
Angelo J. Barbetta
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Xerox Corp
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Xerox Corp
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Publication of EP0302686A3 publication Critical patent/EP0302686A3/en
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08737—Polymers derived from conjugated dienes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/10—Developers with toner particles characterised by carrier particles
    • G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
    • G03G9/1132—Macromolecular components of coatings

Definitions

  • This invention is generally directed to developer compositions, and more specifically, to developer compositions wherein the toner resin particles are comprised of specific styrene butadienes. More specifically, in one embodiment of the present invention, there are provided developer compositions formulated by admixing toner compositions and carrier components, and wherein the toner compositions contain therein as resin particles suspension-polymerized styrene butadiene as illustrated in US-A-4,558,108. Of further importance with respect to the invention of the present application is the selection of carrier particles prepared by a dry coating process wherein a mixture of certain polymers is applied to the carrier enabling insulating particles with relatively constant conductivity parameters; and also wherein the triboelectric charge on the carrier can vary significantly depending on the coatings selected.
  • Developer compositions of the present invention possess at low (about 20 percent) and high (about 80 percent) relative humidities stable triboelectric charging values for extending time periods exceeding, for example, two million imaging cycles; rapid admix characteristics; excellent blocking and fusing properties; and excellent aging characteristics.
  • the toner and developer compositions of the present invention are particularly useful in electrophotographic printing and imaging systems, especially xerographic imaging processes.
  • the triboelectric charge on the carrier particles can be preselected independent of the conductivity depending, for example, on the polymer composition applied to the carrier cores.
  • the electrophotographic process and particularly the xerographic process, is well known. This process involves the formation of an electrostatic latent image on a photoreceptor, followed by development, and subsequent transfer of the image to a suitable substrate.
  • xerographic imaging processes Numerous different types of xerographic imaging processes are known wherein, for example, insulative developer particles or conductive toner compositions are selected depending on the development systems used.
  • triboelectric charging values associated therewith, as it is these values that enable continued constant developed images of high quality and excellent resolution; and admixing characteristics.
  • toner and developer compositions wherein there are selected as the toner resin styrene acrylates, styrene methacrylates, and certain styrene butadienes including those available as Pliolites.
  • Other resins have also been selected for incorporation into toner compositions, inclusive of the polyesters as illustrated in US-A-3,590,000.
  • single-component magnetic toners can be formulated with styrene butadiene resins, particularly those resins available as Pliolite.
  • positively-charged toner compositions containing various resins, inclusive of certain styrene butadienes and charge-enhancing additives are known.
  • carrier particles a number of different carrier particles are known, reference US-A-3,590,000 and 4,233,387, wherein coated carrier components for developer mixtures which are comprised of finely-divided toner particles clinging to the surface of the carrier particles are recited.
  • coated carrier particles obtained by mixing carrier core particles of an average diameter of from 30 to 1,000 »m with from 0.05 to 3.0 percent by weight, based on the weight of the coated carrier particles, of thermoplastic resin particles.
  • the carrier particles consist of a core with a coating thereover comprised of polymers.
  • the carrier particles can be prepared by mixing low-density porous magnetic, or magnetically attractable, metal core carrier particles with from, for example, between 0.05 and 3 percent by weight, based on the weight of the coated carrier particles, of polymers until adherence thereof to the carrier core by mechanical impaction or electrostatic attraction; heating the mixture of carrier core particles and polymers to a temperature of between 93°C to 288°C for a period of from 10 to 60 minutes, enabling the polymers to melt and fuse to the carrier core particles, cooling the coated carrier particles; and thereafter classifying the obtained carrier particles to a desired particle size.
  • the carrier compositions can be comprised of core materials including iron with a dry polymer coating mixture thereover. Subsequently, developer compositions can be generated by admixing the aforementioned carrier particles with a toner composition comprised of resin particles and pigment particles.
  • carriers obtained by applying insulating resinous coatings to porous metallic carrier cores using solution coating techniques are undesirable from many viewpoints.
  • the coating material will usually reside in the pores of the carrier cores, rather than at the surfaces thereof; and therefore is not available for triboelectric charging when the coated carrier particles are mixed with finely-divided toner particles.
  • Attempts to resolve this problem by increasing the carrier coating weights, for example, to as much as 3 percent or greater to provide an effective triboelectric coating to the carrier particles necessarily involves handling excessive quantities of solvents, and further usually these processes result in low product yields.
  • solution-coated carrier particles when combined and mixed with finely-divided toner particles, provide in some instances triboelectric charging values which are too low for many uses.
  • the powder coating process selected for the carrier components of the present invention overcomes these disadvantages, and further enables developer mixtures that are capable of generating high and useful triboelectric charging values with finely-divided toner particles; and also wherein the carrier particles are of substantially constant conductivity. Further, when resin coated carrier particles are prepared by the powder coating process of the present invention, the majority of the coating materials are fused to the carrier surface thereby reducing the number of toner impaction sites on the carrier material.
  • the carrier particles of the present invention independent of one another, desirable triboelectric charging characteristics and conductivity values; that is, for example, the triboelectric charging parameter is not dependent on the carrier coating weight as is believed to be the situation with the process of US-A-4,233,387 wherein an increase in coating weight on the carrier particles may function also to permit an increase in the triboelectric charging characteristics.
  • the carrier compositions and process of the present invention there can be formulated developers with selected triboelectric charging characteristics and/or conductivity values in a number of different combinations.
  • the carrier composition or developer composition can be placed on a 37 mm diameter magnetic roll, followed by applying a voltage across the composition, and measuring with a probe the amount of current which passes through the carrier composition or the developer composition to a measurement electrode for a specific applied voltage.
  • the measurement electrode surrounded by a grounded guard plate has a surface area of 3.0 cm2, and the developer roll to electrode spacing is usually about 2.54 millimeters.
  • the breakdown potential is that potential at which these components begin to conduct large electrical currents, that is currents approaching 0.1 milliamps.
  • the developer compositions of the present invention possess triboelectric charging values of from 10 to 35 microcoulombs per gram on the carrier particles as determined by the known Faraday Cage technique.
  • the developers of the present invention can be formulated with constant conductivity values with different triboelectric charging characteristics by, for example, maintaining the same coating weight on the carrier particles and changing the polymer coating ratios.
  • toner and developer compositions with other improved characteristics, including superior aging properties. Thus, there is a need for developer compositions with stable charging characteristics.
  • developer compositions comprised of positively-charged toner compositions with suspension-polymerized styrene butadiene resins, and carrier particles prepared by a powder-coating process; and wherein the carrier particles are comprised of a core with a coating thereover comprised of a mixture of polymers that are not in close proximity in the triboelectric series.
  • developer compositions comprised of a toner composition comprised of suspension-polymerized styrene butadiene polymers, pigment particles, and charge-enhancing additives; and carrier components comprised of a carrier core with a coating thereover comprised of a polymer mixture with from 10 to 90 percent by weight of a first polymer, and from 90 to 10 percent by weight of a second polymer, which first and second polymers are not in close proximity in the triboelectric series.
  • the toner compositions selected are comprised of suspension-polymerized styrene butadiene resins, pigment particles, inclusive of carbon black, magnetites, and charge-enhancing additives.
  • suspension-polymerized styrene butadiene resins are illustrated in US-A-4,558,108.
  • these resin particles are prepared by a process which comprises forming a copolymer of styrene and butadiene comprising providing an aqueous phase comprising water, styrene monomer, butadiene monomer, a suspension-stabilizing agent, and a chain-propagating amount of a free-radical polymerization initiator insoluble in water, soluble in said styrene monomer, soluble in said butadiene monomer, and having a 1 hour half-life between 50°C and 130°C, with the ratio of styrene monomer to butadiene monomer being between 80:20 and 95:5 by weight; the weight proportion of water to the combination of said styrene monomer and said butadiene monomer being between 8:1 and 2:1, said suspension-stabilizing agent consisting essentially of a finely-divided, difficultly water-soluble powder and a vapor phase comprising an inert gas and butadiene monomer; heating said a
  • the resin particles are present in a sufficient, but effective amount, thus when 10 percent by weight of pigment or colorant such as carbon black is contained therein about 90 percent by weight of resin material is selected.
  • the toner composition is comprised of from 75 to 95 percent by weight of toner resin particles, from 2 to 20 percent by weight of pigment particles such as carbon black, and from 0.1 to 10 percent by weight of charge-enhancing additive providing the total amount of components equals 100 percent.
  • pigments or dyes can be selected as the colorant for the toner particles including, for example, carbon black, nigrosine dye, lamp black, iron oxides, magnetites, and mixtures thereof.
  • the pigment which is preferably carbon black, should be present in a sufficient amount to render the toner composition highly contrasting.
  • the pigment particles are present in amounts of from 2 to 20 percent by weight based on the total weight of the toner composition, however, lesser or greater amounts of pigment particles can be selected.
  • magnetites which are comprised of a mixture of iron oxides (FeO.Fe2O3), in most situations including those commercially available such as Mapico Black, can be selected for incorporation into the toner compositions illustrated herein.
  • the aforementioned magnetite particles are present in various effective amounts, generally however, they are present in the toner composition in an amount of from 10 to 25 percent by weight, and preferably in an amount of from 16 to 19 percent by weight.
  • Other magnetites not specifically disclosed herein may be selected.
  • a number of different charge-enhancing additives may be selected for incorporation into the toner compositions of the present invention to enable these compositions to acquire a positive charge thereon of from, for example, 10 to 35 microcoulombs per gram.
  • charge-enhancing additives include alkyl pyridinium halides, especially cetyl pyridinium chloride, reference US-A-4,298,672; organic sulfate or sulfonate compositions, reference US-A-4,338,390; distearyl dimethyl ammonium methyl sulfate, reference US-A-4,560,635; and other similar known charge-enhancing additives.
  • These additives are usually incorporated into the toner in an amount of from 0.1 to 20 percent by weight, and preferably these additives are present in an amount of from 0.2 to 5 percent by weight.
  • the toner compositions of the present invention can be prepared by a number of known methods, including melt blending the toner resin particles, the pigment particles or colorants, and charge-enhancing additives; followed by mechanical attrition. Other methods include those well known in the art such as spray drying, melt dispersion, dispersion polymerization, extrusion processing, and suspension polymerization. In one dispersion polymerization method, a solvent dispersion of the resin particles and the pigment particles is spray dried under controlled conditions to result in the desired product.
  • Important characteristics associated with the toner compositions of the present invention include a blocking temperature of greater than 57°C, and a fusing temperature latitude of from 149 to 232°C.
  • the aforementioned toners possess stable triboelectric charging values of from 10 to 30 microcoulombs per gram for an extended number of imaging cycles exceeding, for example, in some embodiments two million developed copies.
  • an important factor for the slow, or substantially no degradation in the triboelectric charging values resides in the rheological properties of the suspension-polymerized butadiene resins selected.
  • the carrier particles selected can be prepared by mixing low-density porous magnetic, or magnetically-attractable, metal core carrier particles with from, for example, between 0.05 and 3 percent by weight based on the weight of the coated carrier particles, of a mixture of polymers not in close proximity in the triboelectric series until adherence thereof to the carrier core by mechanical impaction or electrostatic attraction; heating the mixture of carrier core particles and polymers to a temperature, for example, of between from 93 to 288°C, for a period of from 10 to 60 minutes enabling the polymers to melt and fuse to the carrier core particles; cooling the coated carrier particles; and thereafter classifying the obtained carrier particles to a desired particle size.
  • carrier particles especially particles with a breakdown voltage of greater than 1,000 volts, comprised of a core with a coating thereover comprised of a mixture of a first dry polymer component and a second dry polymer component. Therefore, the aforementioned carrier compositions can be comprised of core materials including iron with a dry polymer coating mixture thereover.
  • the carrier particles selected for the developer compositions of the present invention are prepared by (1) mixing carrier cores with a polymer mixture comprising from 10 to 90 percent by weight of a first polymer, and from 90 to 10 percent by weight of a second polymer; (2) dry mixing the carrier core particles and the polymer mixture for a sufficient period enabling the polymer mixture to adhere to the carrier core particles; (3) heating the mixture of carrier core particles and polymer mixture to a temperature of between 93 to 288°C, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.
  • developer compositions of the present invention can be generated by admixing the aforementioned carrier particles with a toner composition comprised of resin particles and pigment particles.
  • Suitable solid core carrier materials can be selected. Characteristic carrier properties of importance include those that will enable the toner particles to acquire a positive charge, and carrier cores that will permit desirable flow properties in the developer reservoir present in the xerographic imaging apparatus. Also of importance with regard to the carrier core properties are, for example, suitable magnetic characteristics that will permit magnetic brush formation in magnetic brush development processes; and wherein the carrier cores possess desirable mechanical aging characteristics. Examples of carrier cores that can be selected include iron, steel, ferrites, magnetites, nickel, and mixtures thereof. Preferred carrier cores include ferrites and sponge iron, or steel grit with an average particle size diameter of from between 30 to 200 »m.
  • polymer coatings selected for the carrier particles of the present invention include those that are not in close proximity in the triboelectric series.
  • polymer mixtures used are polyvinylidenefluoride with polyethylene, polymethylmethacrylate and copolyethylenevinylacetate; copolyvinylidenefluoride, tetrafluoroethylene and polyethylene; polymethylmethacrylate and copolyethylene vinylacetate; and polymethylmethacrylate and polyvinylidenefluoride.
  • Other related polymer mixtures not specifically mentioned herein can be selected.
  • the percentage of each polymer present in the carrier coating mixture can vary depending on the specific components selected, the coating weight, and the properties desired.
  • the coated polymer mixtures used contain from 10 to 90 percent of the first polymer, and from 90 to 10 percent by weight of the second polymer.
  • a high triboelectric charging value when a high triboelectric charging value is desired, that is exceeding 30 microcoulombs per gram, there is selected from 50 percent by weight of the first polymer such as a polyvinylidene fluoride, commercially available as Kynar 301F; and 50 percent by weight of a second polymer such as polymethylacrylate.
  • the first polymer such as a polyvinylidene fluoride, commercially available as Kynar 301F
  • a second polymer such as polymethylacrylate.
  • a lower triboelectric charging value when a lower triboelectric charging value is required, less than for example 10 microcoulombs per gram, there is selected from 30 percent by weight of the first polymer; and 70 percent by weight of the second polymer.
  • toner particles Generally, from 1 part to 5 parts by weight of toner particles are mixed with from 10 to 300 parts by weight of the carrier particles illustrated herein enabling the formation of developer compositions.
  • colored toner compositions comprised of toner resin particles, carrier particles, and as pigments or colorants present in the toner, magenta, cyan, or yellow particles as well as mixtures thereof. More specifically, illustrative examples of magenta materials that may be selected as pigments include 1,9-dimethyl-substituted quinacridone and anthraquinone dye identified in the Color Index as Cl 60720; Cl Dispersed Red 15, a diazo dye identified in the Color index as Cl 26050; Cl Solvent Red 19; and the like.
  • cyan materials that may be used as pigments include copper tetra-4(octadecyl sulfonamido) phtalocyanine; X-copper phthalocyanine pigment listed in the Color Index as Cl 74160; Cl Pigment Blue; and Anthrathrene Blue, identified in the Color Index as Cl 69810; Special Blue X-2137; and the like; while illustrative examples of yellow pigments that may be selected are diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the Color Index as Cl 12700; Cl Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the Color Index as Foron Yellow SE/GLN; Cl Dispersed Yellow, 33, 2,5-dimethoxy-4-sulfonanilide phenylazo-4′-chloro-2,5-dimethoxy acetoacetanilide; Permanent Yellow FGL; and the like.
  • the toner and developer compositions of the present invention may be selected for use in electrophotographic imaging processes containing therein conventional photoreceptors, including inorganic and organic photoreceptor imaging members.
  • imaging members are selenium, selenium alloys; and selenium or selenium alloys containing therein additives or dopants such as halogens. These imaging members are conventionally charged positively. In a printer application, the image area can be discharged by light, and a high positive electrical DC bias applied to the development roll. This will permit the development of the positively-charged toner on to the inorganic photoreceptor imaging member.
  • organic photoreceptors illustrative examples of which include layered photoresponsive devices comprised of transport layers and photogenerating layers, reference US-A-4,265,990, and other similar layered photoresponsive devices.
  • generating layers are trigonal selenium, metal phthalocyanines, metal-free phthalocyanines and vanadyl phthalocyanines.
  • photogenerating pigments there can be selected as photogenerating pigments, squaraine compounds, thiapyrillium materials, and the like.
  • charge-transport molecules there can be selected the aryl amines disclosed in the ′990 patent. These layered members are conventionally charged negatively, thus requiring a positively-charged toner.
  • the developer compositions of the present invention are particularly useful in electrostatographic imaging processes and apparatuses wherein there is selected a moving transporting means and a moving charging means; and wherein there is selected a deflected flexible layered imaging member, reference US-A-4,394,429 and 4,368,970. Images obtained with the developer compositions of the present invention possess dark, uniform solids having optical densities greater than 1.20, excellent halftones, and sharp line resolution with acceptable or substantially no background deposits.
  • the carrier coatings include therein conductive particles such as carbon black in various effective amounts.
  • the aging fixture selected consists of a developer housing with a single development roll moving in the opposite direction as the photoreceptor drum comprised of an arsenic selenium alloy, 99 percent selenium, 1 percent arsenic, deposited on an aluminum substrate.
  • This photoreceptor was maintained in a discharged state in that it is discharged to substantially zero volts by a fluorescent lamp and a corotron.
  • the housing was sequentially electrically biased with 95 volts DC, and 580 volts DC to result in background development for 95 percent of the drum cycle and solid area image development for 5 percent of the cycle.
  • the density of the background and image patches on the photoreceptor was monitored continuously by an infrared sensor.
  • the output of the sensor controls the toner dispensing systems in that this sensor determines the amount of toner that was added to the developer housing, and hence to the electrostatic image. Further, the imaged toner was removed after each cycle by a brush cleaner, preceded by dicorotron charging, in order to provide a clean selenium alloy photoreceptor for each development step.
  • a brush cleaner preceded by dicorotron charging, in order to provide a clean selenium alloy photoreceptor for each development step.
  • key developer composition properties were measured at different times, for example, t1 and t2, including toner concentration and triboelectric charging values.
  • a magnetic toner composition containing 1 percent by weight of the charge-enhancing additive distearyl dimethyl ammonium methyl sulfate, 4 percent by weight of carbon black, 16 percent by weight of Mapico Black magnetite particles, and 79 percent by weight of styrene butadiene resin particles, with 10 parts of styrene, and 1 part of butadiene, which resin was formulated by an emulsion polymerized process as illustrated in US-A-4,469,770.
  • the extrusion process involves melt mixing the above components in a ZSK-53 extruder purchased from Werner and Pfleiderer Corporation, Ramsey, N.J..
  • a developer composition was then prepared by mixing 200 grams of carrier particles, and 6 grams of the above prepared toner composition, wherein the carrier particles were comprised of a Toniolo atomized steel core, 120 »m in diameter, containing as a coating thereon 1.25 percent of a copolymer of vinylchloride/chlorotrifluoroethylene with the coating having dispersed therein 7.5 percent of carbon black particles. Mixing was accomplished by placing the toner and carrier particles in an 8 ounce glass jar with a tightened screw cap thereon on a paint shaker for 10 minutes.
  • a t 2 A t 1 exp [-k(t2 - t1)], wherein t1 was 47 hours, t2 was 98 hours, A t 1 was 46.3 microcoulombs per gram, A t 2 was 28 microcoulombs per gram, and k is the degradation rate.
  • the degradation rate was 0.0098 hours ⁇ 1. Also, the life of this developer, which is inversely proportional to the degradation rate constant k, would be 70 hours (about 280,000 copies).
  • a magnetic toner and developer composition was prepared by repeating the procedure of Example I with the exception that there was selected in place of the emulsion-polymerized styrene butadiene, a suspension-polymerized styrene butadiene prepared by the process as illustrated in US-A-4,558,108.
  • the toner resulting possessed a triboelectric charge of a positive 30 microcoulombs per gram.
  • the triboelectric aging curve was similar to that of the developer of Example I with the exception that the long term degradation rate k was 0.0063 hour ⁇ 1,t1 was 17 hours, t2 was 72 hours, A t 1 was 107 microcoulombs per gram, and A t 2 was 73 microcoulombs per gram. For this developer, the life would thus be 110 hours (about 440,000 copies).
  • a magnetic toner and developer composition of the present invention was prepared by repeating the procedure of Example II with the exception that there was selected as carrier particles a steel core with a coating thereover of 0.7 percent by weight of a dry mixture of 40 percent by weight of polyvinylidene fluoride available as Kynar 301F, and 60 percent by weight of polymethyl methacrylate.
  • the aforementioned components were admixed for 60 minutes in a Munson MX-1 blender rotating at 27.5 RPM. Thereafter, the carrier particles resulting were metered at a rate of 110 grams per minute into a rotating tube furnace, which was maintained at a temperature of 208°C.
  • a developer composition was then prepared by mixing 200 grams of the prepared carrier particles, and 6 grams of the toner composition of Example II in an 8 ounce glass jar with a tightened screw cap thereon on a paint shaker for 10 minutes. Subsequent to the removal of a sample of developer composition, a standard blow off tribo measurement was affected and there resulted on the toner a positive triboelectric charge of 15 microcoulombs per gram.
  • the life was 280 hours (about 1,100,000 copies), t1 was 67 hours, t2 was 142 hours, A t 1 was 211 microcoulombs per gram, and A t 2 was 175 microcoulombs per gram.
  • a magnetic toner composition was prepared by repeating the procedure of Example I with the exception that there was selected 76.5 percent of the resin, 4 percent of carbon black, 19 percent of magnetite, and 0.5 percent of distearyl dimethyl ammonium methyl sulfate. Subsequently, this toner was mixed with the carrier particles of Example III with the exception that the coating mixture contained 35 percent by weight of Kynar 301F, and 65 percent by weight of polymethyl methacrylate. Subsequent to mixing in a paint shaker for 10 minutes, the toner had a triboelectric charge thereon of 9.5 microcoulombs per gram.
  • this developer composition had a tribo degradation rate of 0.0021 hour ⁇ 1, t1 was 89 hours, t2 was 204 hours, A t 1 was 81 microcoulombs per gram, and A t 2 was 64 microcoulombs per gram. Also, it is believed that this developer would have a life of 330 hours, or 1,300,000 copies.
  • a developer composition was prepared by repeating the procedure of Example IV with the exception that there was selected the suspension-polymerized styrene butadiene of Example II, and there resulted a toner with a triboelectric charge thereon of 17 microcoulombs per gram, and a tribo degradation rate of only 0.0013 hour ⁇ 1; and wherein t1 was 79 hours, t2 was 237 hours, A t 1 was 108 microcoulombs per gram, and A t 2 was 88 microcoulombs per gram. The life of this developer was projected to be 500 hours, or 2,000,000 copies.
  • the toner of this Example was placed in a glove box, and exposed to a relative humidity of 80 percent at about 80°F for 24 hours, and there resulted only a 20 percent loss for the triboelectric charge on the toner, thus reducing the developer life to 335 hours, or 1,340,000 copies from 2,000,000 copies as compared to a 57 percent charge loss for the toner of Example IV. Additionally, the admixing time was 15 seconds subsequent to the addition of one percent of the above-prepared toner composition to the developer composition of this Example.
  • a developer composition was prepared by repeating the procedure of Example V with the exception that there was selected 15.5 percent by weight of magnetite, and 79.5 percent by weight of the suspension-polymerized styrene butadiene resin. This developer was then incorporated into a high speed (greater than 70 copies per minute) xerographic imaging test fixture wherein the imaging member selected was comprised of a supporting substrate of 'Mylar' overcoated with a photogenerating layer of trigonal selenium, 95 percent by weight, dispersed in a polycarbazole resinous binder, and as a top layer in contact with the photogenerating layer a charge-transport layer of N,N′-bis(3-methylphenyl)1,1′-biphenyl-4,4′ diamine molecules, 55 percent by weight, dispersed in 45 percent by weight of a polycarbonate resinous binder commercially available as Makrolon, reference US-A-4,265,990.
  • the toner composition of Example III was prepared into a developer composition by admixing carrier particles therewith comprised of an oxidized steel core, available from Toniolo Inc., with a semicontinuous dry fused coating (carrier core and coating mixed for 70 minutes prior to fusing, reference US-A-4,233,387) thereover of 0.15 percent by weight of polyvinylidene fluoride.
  • carrier particles comprised of an oxidized steel core, available from Toniolo Inc.
  • carrier core and coating mixed for 70 minutes prior to fusing reference US-A-4,233,387
  • the breakdown voltage of this carrier was less than 100 volts, which results in a significant loss of the full gray scale reproduction for halftones, and the triboelectric charge of the resulting developer mixture was 45 microcoulombs per gram.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Claims (10)

  1. Composition de développateur comprenant des particules de support revêtues par un mélange de 10 à 90 pourcent en poids d'un premier polymère et 90 à 10 pourcent en poids d'un autre polymère, les polymères n'étant pas en proximité proche l'un de l'autre dans les séries triboélectriques et les particules de toner constituées d'un copolymère de styrène et de butadiène contenant des pigments et des additifs améliorant la charge,
       caractérisé en ce que
       le copolymère de styrène et de butadiène a été préparé par un procédé de polymérisation en suspension.
  2. Développateur selon la revendication 1, dans lequel le copolymère de styrène et de butadiène est constitué de 80 à 90 % en poids de styrène et de 20 à 10 % en poids de butadiène.
  3. Développateur selon l'une quelconque des revendications précédentes, dans lequel les additifs améliorant la charge sont des halogénures d'alkylpyridinium, des sulfates et sulfonates organiques ou des méthylsulfates de distéaryldiméthylammonium.
  4. Développateur selon l'une quelconque des revendications précédentes, dans lequel le mélange de polymères recouvrant les particules de support est constitué de 30 à 60 % en poids du premier polymère et de 70 à 40 % en poids du second polymère.
  5. Développateur selon l'une quelconque des revendications précédentes, dans lequel le premier polymère est du polyvinylidènefluorure et le second polymère est le méthacrylate de polyméthyle.
  6. Développateur selon l'une quelconque des revendications précédentes, dans lequel la charge triboélectrique sur les particules de toner est de 10 à 35 microcoulombs.
  7. Développateur selon l'une quelconque des revendications précédentes, dans lequel la tension de rupture des particules de toner est supérieure à 1 000 volts.
  8. Développateur selon l'une quelconque des revendications précédentes, dans lequel le copolymère de styrène et de butadiène est présent en une quantité de 70 à 85 % en poids.
  9. Développateur selon l'une quelconque des revendications précédentes, incluant de 10 à 25 % en poids de magnétite.
  10. Développateur selon l'une quelconque des revendications précédentes, dans lequel les particules de support sont constituées d'acier, de fer, de nickel ou de ferrites.
EP19880307085 1987-08-03 1988-08-01 Compositions de développateur Expired - Lifetime EP0302686B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US8126187A 1987-08-03 1987-08-03
US81261 1987-08-03

Publications (3)

Publication Number Publication Date
EP0302686A2 EP0302686A2 (fr) 1989-02-08
EP0302686A3 EP0302686A3 (en) 1990-08-01
EP0302686B1 true EP0302686B1 (fr) 1995-02-22

Family

ID=22163084

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880307085 Expired - Lifetime EP0302686B1 (fr) 1987-08-03 1988-08-01 Compositions de développateur

Country Status (4)

Country Link
EP (1) EP0302686B1 (fr)
JP (1) JP2647693B2 (fr)
CA (1) CA1329718C (fr)
DE (1) DE3853109T2 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5567562A (en) * 1995-01-17 1996-10-22 Xerox Corporation Coated carrier particles and processes thereof
US5994015A (en) * 1998-01-23 1999-11-30 Nashua Corporation Carrier materials

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4297427A (en) * 1978-01-26 1981-10-27 Xerox Corporation Polyblend coated carrier materials
CA1134662A (fr) * 1980-05-12 1982-11-02 N. Ganesh Kumar Resines toner de styrene butadiene
CA1249392A (fr) * 1982-12-27 1989-01-24 Peter G. Odell Polymerisation d'un melange aqueux
US4469770A (en) * 1982-12-27 1984-09-04 Xerox Corporation Styrene butadiene plasticizer toner composition blends
JPH0719080B2 (ja) * 1985-10-30 1995-03-06 ゼロックス コ−ポレ−ション キャリヤー粒子の製造方法

Also Published As

Publication number Publication date
EP0302686A3 (en) 1990-08-01
JPS6450058A (en) 1989-02-27
EP0302686A2 (fr) 1989-02-08
DE3853109D1 (de) 1995-03-30
CA1329718C (fr) 1994-05-24
DE3853109T2 (de) 1995-10-12
JP2647693B2 (ja) 1997-08-27

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