US3592675A - Method for developing latent electrostatic images - Google Patents

Method for developing latent electrostatic images Download PDF

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Publication number
US3592675A
US3592675A US673600A US3592675DA US3592675A US 3592675 A US3592675 A US 3592675A US 673600 A US673600 A US 673600A US 3592675D A US3592675D A US 3592675DA US 3592675 A US3592675 A US 3592675A
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Prior art keywords
image
powder
toner
developed
finely divided
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Expired - Lifetime
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US673600A
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English (en)
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Tung-Nan Cheng
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Azoplate Corp
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Azoplate Corp
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    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G03G13/08—Developing using a solid developer, e.g. powder developer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/095—Removing excess solid developer, e.g. fog preventing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/005—Materials for treating the recording members, e.g. for cleaning, reactivating, polishing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09708—Inorganic compounds
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09708—Inorganic compounds
    • G03G9/09725—Silicon-oxides; Silicates
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G03G9/09775—Organic compounds containing atoms other than carbon, hydrogen or oxygen
    • 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
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09783—Organo-metallic compounds
    • G03G9/09791—Metallic soaps of higher carboxylic acids

Definitions

  • the toners commonly used in electrophotography comprise natural or synthetic resins in finely divided powder form. When used for the development of latent electrostatic images, such a toner is mixed with somewhat larger particles of a carrier which generally comprises an inorganic material, e.g. iron powder.
  • Iron powder is particularly effective as a carrier as it can be moved magnetically, for example, by means of a roller magnetized by electric current.
  • the toner present on the surface of the iron powder is thus applied in the desired manner to the surface of the electrostatic image to be developed.
  • an even application of toner to fairly large solid areas is possible.
  • toners consisting of two components which have approximately the same particle size.
  • One toner component acquires a positive charge during handling and the other toner component acquires a negative charge.
  • the use of these toners gives particularly desirable results with respect to freedom from background and sharpness of images produced therewith.
  • the two component toner system provides developed electrostatic images with cleaner non-image areas than does the single component toner system background still remains.
  • the present invention provides a method for developing latent electrostatic images in which copies are obtained having much cleaner non-image areas.
  • a latent electrostatic image is first developed with a single component or double component toner using any of the known methods of development, such as using the toner in admixture with an iron particle carrier and applying the mixture to the image to be developed by means of a magnetic roller or magnetic brush.
  • the image may be developed by cascade development, powder cloud development, or sprinkling the toner on the latent image.
  • the developed electrostatic image having some toner adhering in the nonimage areas, then is passed in contact with one or more magnetic rollers containing another powder in admixture with an iron particle carrier.
  • the developer powder on the second magnetic roller picks up the weakly or loosely bonded colored toner in the non-image areas while leaving 3,592,675 Patented July 13, 1971 the strongly bonded colored toner in the image areas.
  • the developed image is then fixed by heat.
  • the accompanying drawing shows one embodiment of the method of the present invention in which a zinc oxide electrophotographic paper having a negatively charged latent electrostatic image thereon is passed in contact with an image developer comprising a positively charged toner in admixture with an iron particle carrier and the developed powder image, with some toner particles in the non-image areas, is passed in contact with a cleaning developer comprising aluminum sulfate, for example, the admixture with iron particles, the mixture being applied by means of a magnetic brush to produce a developed powder image with clean non-image areas.
  • a bias voltage may be applied for example to the magnetic brush used to apply the cleaning developer to the developed powder image.
  • the zinc oxide electrophotographic paper can be any other known electrophotographic material such as metallic bases, including aluminum, copper, and the like, having inorganic or organic photoconductors thereon or the base may be paper having photoconductors other than zinc oxide, such as the other known inorganic and organic photoconductive materials.
  • the development of the latent electrostatic image and the application of the cleaning developer to the developed image is performed in the dark.
  • the fusible resin powders which may be employed to develop the image areas are the known resins, such as natural and synthetic resins, including colophony, copals, dammar resin, asphalts, colophony-modified phenol resins, polyacrylic acid resins and polystyrenes, as well as mixtures of these resins.
  • Inorganic and/ or organic pigments and dyestuffs may be added to these resins to impart a definite polarity thereto.
  • suitable substances are carbon black, zinc oxide, titanium dioxide, barium sulfate, minium and dyestuffs such as those listed in Schultzs Farbstolftabellen, vol. I, 7th edition (1931). Also, mixtures of such dyestuffs and/ or pigments may be used.
  • Minute quantities of these substances are often sufficient to impart a polarity to the resins. It is also advantageous to incorporate small quantities of waxes and/ or organic compounds of low melting point and their substitution products, e.g. 0.1 to 10 percent, preferably 1 to 5 percent by weight, to the toner component to influence in a desirable direction its melting point and adhesive power.
  • Waxes suitable for this purpose include natural waxes such as carnauba wax, beeswax, Japan wax, montan wax, ceresine and synthetic waxes such as those marketed by A-wax, OP-wax, SPO-Wax, V-wax, O-wax, E-wax, Hard Wax H, Hard Wax W, various Waxes known as Ruhrwachse, and particularly the products available as Gersthofener waxes with the codings S, L, O, and OP.
  • natural waxes such as carnauba wax, beeswax, Japan wax, montan wax, ceresine
  • synthetic waxes such as those marketed by A-wax, OP-wax, SPO-Wax, V-wax, O-wax, E-wax, Hard Wax H, Hard Wax W
  • various Waxes known as Ruhrwachse and particularly the products available as Gersthofener wax
  • Suitable organic compounds of low melting point in clude, in particular, substituted and unsubstituted aromatic compounds having melting points between 40 and C., for example naphthols, such as l-naphthol and 2-naphthol, aromatic compounds such as acenaphthalene, acylamino compounds such as acetanilide, halogenated aromatic compounds, such as p-dibromobenzene, amino compounds such as 2,4-diamino toluene, o-phenylene diamine, phenols such as resorcinol, and diphenylamine and derivatives thereof.
  • naphthols such as l-naphthol and 2-naphthol
  • aromatic compounds such as acenaphthalene
  • acylamino compounds such as acetanilide
  • halogenated aromatic compounds such as p-dibromobenzene
  • amino compounds such as 2,4-diamino tolu
  • the powder which is admixed with finely divided iron carrier particles and is used as a cleaning developer in the present invention may be organic or inorganic. Exemplary of such powders are those listed in the table below, which table also shows the optimum concentration of the powder in admixture with finely divided iron carrier particles and also the triboelectric polarity of the powder:
  • the finely divided cleaning developer powders in admixture with iron carrier particles form a soft layer around the magnetic tubes of the magnetic brush so that it does not scratch the unfixed powder image.
  • the triboelectric characteristics of the finely divided powders when admixed with an iron carrier also consti tute a factor in the powder selection.
  • the finely divided powder used in the cleaning step should preferably be negative in polarity, and vice versa.
  • finely divided powders which show both polarities when mixed with iron carrier particles, or mixtures of two or more different finely divided powders also are useful.
  • the developer on the first magnetic roller shown in the drawing used to develop the latent image may contains, as is known, one part of toner to 10 to parts of iron particles by weight. Where a double toner is used, the ratio of the fusible toner to the inorganic toner, such as kieselguhr, may vary from about 1 to l to 1 to 10, by weight.
  • the ratio of the colorless toner, to the iron carrier particles may vary from 1 to 4 to 1 to 200 preferably from 1 to 5 to l to 200 by weight.
  • the preferred particle size of the iron carrier particles is from to 200g.
  • the advantages of using a single component colored toner followed by the cleaning action of the magnetic roller in the present invention, as opposed to the use of a double toner applied by a single magnetic roller, is that there is no adhesion of the cleaning toner, such as kieselguhr, to the non-image areas. This eliminates the step of cleaning the kieselguhr from the surface of the final copy and, also, more even image areas can be obtained, especially on large solid areas.
  • the bias voltage may be applied, depending upon the nature of the toner, to either or both magnetic rollers shown in the drawing to obtain the optimum results.
  • bias voltage may vary within a wide range depending upon the method of application.
  • the preferred range is between 200 and 150 volts. DC, however, lower or higher voltages may be used.
  • the connection of the power source to the magnetic brush depends upon the polarity of the finely divided powder in the cleaning developer. For example, if the finely divided powder is negative in polarity then the magnetic brush preferably is connected to the positive terminal, the negative terminal being grounded, and vice versa. For safety, the support of the photoconductive coating is to be grounded if a bias voltage is applied.
  • the rotation of the magnetic brush which applies the cleaning developer can be in either direction with respect to the direction of travel of the photoconductive surface shown in the drawing, but the surface speed of the rotaing cleaning magnetic brush should be greater than the speed of travel of the photoconductive surface if it is in the same direction.
  • EXAMPLE 1 A zinc oxide coated electrophotographic paper is negatively charged by means of a corona discharge and then exposed to a light image.
  • the negatively charged latent image is developed with a positively charged colored toner in admixture with an iron particle carrier by means of a magnetic brush.
  • the resulting developed image shows some toner or background in the non-image areas, as is customary.
  • the electrophotographic paper with the powder image and some background is then brought into surface contact with the cleaning device shown in the drawings which consists of a. rotating magnetic brush and a cleaning developer composed of 15 percent of finely divided aluminum sulfate and 85 percent of finely divided iron particles, by weight, whereby nearly all of the toner in the non-image areas is removed without loss of image density.
  • the powder image is then fixed by application of heat, in known manner.
  • Example 2 The procedure of Example 1 is followed except that a basis voltage of 50 volts DC is applied to the cleaning device shown in the drawing with the positive terminal connected to the cleaning device and the negative terminal and the support of the photoconductive coating connected to ground. The cleaning device is insulated from the remainder of the machine.
  • EXAMPLE 3 An organic photoconductive substance and a binder are dissolved in a solvent and coated on an aluminum substrate.
  • the photoconductive surface is positively charged by means of a corona discharge.
  • the photoconductive aluminum plate is then exposed to a light image.
  • the positively charged latent electrostatic image then is developed with a negatively charged colored toner, using beads as a carrier, by means of the cascade developing method.
  • the developed powder image with some toner particles in the non-image areas is then brought into surface contact with the cleaning device shown in the drawings consisting of a magnetic brush and a cleaning developer which is composed of 16 percent of aluminum stearate and 85 percent of iron particles, by weight.
  • An electrostatic image with much cleaner non-image areas is obtained.
  • the powder image is then fixed by application of heat, in known manner.
  • EXAMPLE 4 The procedure of Example 3 is repeated except that a bias voltage of volts DC is applied to the cleaning device, which latter is insulated from the remainder of the machine.
  • the negative terminal is connected to the cleaning device and the positive terminal and the aluminum support of the photoconductive coating is grounded.
  • EXAMPLE A zinc oxide coated electrophotographic paper is processed according to Example 1 wherein a cleaning developer composition is used consisting of percent by weight of tetrahydrophthalic anhydride and 90 percent by weight of finely divided iron particles.
  • This composition is prepared by first grinding the tetrahydrophthalic anhydride to a particle size between 0.5 and p. and then intimately mixing with the iron powder.
  • EXAMPLE 6 A Zinc oxide coated electrophotographic paper is processed according to Example 1 wherein as a cleaning developer a mixture of an organic compound, in this case 5 percent by weight of para-acetophenetidine and an inorganic compound, in this case 5 percent by weight of aluminum sulfate, with 90 percent of finely divided iron particles by weight is used.
  • a cleaning developer a mixture of an organic compound, in this case 5 percent by weight of para-acetophenetidine and an inorganic compound, in this case 5 percent by weight of aluminum sulfate, with 90 percent of finely divided iron particles by weight is used.
  • the method of the present invention also can be applied to transfer electrophotography, i.e., xerography.
  • a xerographic drum comprising a layer of photoconductive insulating material, such as selenium, on a conductive backing is given a uniform positive electrostatic charge over its surface and then exposed to a light image, thereby forming an electrostatic latent image on the photoconductive layer.
  • the latent image is effected with a negatively charged colored toner brought into surface contact with the photoconductive layer. Thereafter, the developed powder image is transferred to a support to which it may be fixed by application of heat.
  • the electrically charged colored toners adhere to the nonimage areas and result in copies having undesirable background. It is, accordingly, advantageous to contact the powder image immediately after cascade development, but before the transfer of the powder image to a support surface, with the cleaning device of the present invention.
  • the finely divided powder in the cleaning step preferably is positive in polarity when mixed with iron particles.
  • the cleaning step of the present invention can be performed on a powder image that has been transferred before the image has been fixed. In this case, it is preferable to construct the system in a manner such that the unfixed powder image faces downwardly when it passes over and in surface contact with the cleaning magnetic brush.
  • a basis voltage may be applied advantageously to the magnetic brush of the cleaning device when used both after cascade development or after the image has been transferred.
  • a cleaning device can best be described as a web cleaner.
  • transfer electrophotography i.e., xerography
  • a photoconductive cylindrical drum is continuously rotated through a cycle of sequential operations, including charging, exposure, developing, and transfer, resulting in multiple copies; the photoconductive surface is cleaned by means of the present invention before repeating the cycle.
  • the residual toner on the photoconductive surface after transfer of the powder image to the support surface, particularly in the image areas, is first substantially neutralized, then brought into surface contact with the cleaning device, and finally brushed with a rotating fur brush whereby all residue is collected by vacuum and deposited into a filter bag.
  • a method of developing an electrostatic latent image on an image support which comprises contacting the image with a fusible resin powder to develop the image areas and then contacting the developed image and support with a magnetic brush containing a mixture of effective amounts of finely divided iron carrier particles and a second powder which removes undesired fusible resin particles from non-image areas of the support, whereby a developed image with clean non-image areas is obtained.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Cleaning In Electrography (AREA)
US673600A 1967-10-09 1967-10-09 Method for developing latent electrostatic images Expired - Lifetime US3592675A (en)

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US67360067A 1967-10-09 1967-10-09

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US (1) US3592675A (de)
AT (1) AT287494B (de)
BE (1) BE722012A (de)
DE (1) DE1797462C3 (de)
FR (1) FR1585564A (de)
GB (1) GB1210020A (de)
NL (1) NL6814450A (de)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3722018A (en) * 1971-11-08 1973-03-27 Xerox Corp Cleaning apparatus
US3739749A (en) * 1969-10-20 1973-06-19 Minnesota Mining & Mfg Magnetic powder applicator
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3767446A (en) * 1969-07-03 1973-10-23 Xerox Corp Development method with oscillating brush pad
US3783818A (en) * 1970-12-26 1974-01-08 Fuji Xerox Co Ltd Electrophotographic developing process
US3784302A (en) * 1968-10-03 1974-01-08 Xerox Corp Electrophoretic imaging apparatus including application of dynamic stress on the particle suspension
US3802389A (en) * 1971-04-30 1974-04-09 Iwasaki Kk Developing apparatus used in electrophotography
US3831552A (en) * 1972-02-07 1974-08-27 Identicator Corp Fingerprinting apparatus
US3839992A (en) * 1971-02-13 1974-10-08 Ricoh Kk Diazo type photosensitive sheet developing device
US3850662A (en) * 1971-09-10 1974-11-26 Kalle Ag Electrophotographic developing process and apparatus
JPS503344A (de) * 1973-05-10 1975-01-14
US3865080A (en) * 1973-01-17 1975-02-11 Xerox Corp Toner pickoff apparatus
US3920329A (en) * 1974-09-25 1975-11-18 Xerox Corp Background removal apparatus
US3923004A (en) * 1973-12-27 1975-12-02 Xerox Corp Development and cleaning apparatus for reverse path machine
US4073266A (en) * 1975-02-20 1978-02-14 Hoechst Aktiengesellschaft Apparatus for developing a latent electrostatic image on an electrophotographic copying material
US4102306A (en) * 1976-05-31 1978-07-25 Konishiroku Photo Industry Co., Ltd. Developing roller and rinsing device
DE2816501A1 (de) * 1977-04-18 1978-10-19 Du Pont Bepulverungsvorrichtung zum aufbringen von magnetisch anziehbaren tonerteilchen
US4194466A (en) * 1976-11-12 1980-03-25 Hoechst Aktiengesellschaft Electrophotographic apparatus for developing latent electrostatic charge images
US4210448A (en) * 1975-10-21 1980-07-01 Elfotec A.G. Process for electrophotographic image formation and transfer
DE3228094A1 (de) * 1981-08-01 1983-02-17 Konishiroku Photo Industry Co., Ltd., Tokyo Vorrichtung zum entwickeln eines elektrostatischen bildes
US4493882A (en) * 1982-11-29 1985-01-15 Canon Kabushiki Kaisha Image formation method and apparatus
US4641956A (en) * 1980-08-25 1987-02-10 Xerox Corporation Extended nip cleaning system
US4764448A (en) * 1985-04-05 1988-08-16 Mitsubishi Chemical Industries, Ltd. Amorphous silicon hydride photoreceptors for electrophotography, process for the preparation thereof, and method of use

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784302A (en) * 1968-10-03 1974-01-08 Xerox Corp Electrophoretic imaging apparatus including application of dynamic stress on the particle suspension
US3767446A (en) * 1969-07-03 1973-10-23 Xerox Corp Development method with oscillating brush pad
US3739749A (en) * 1969-10-20 1973-06-19 Minnesota Mining & Mfg Magnetic powder applicator
US3754962A (en) * 1970-12-21 1973-08-28 Ibm Development of electrostatic images
US3783818A (en) * 1970-12-26 1974-01-08 Fuji Xerox Co Ltd Electrophotographic developing process
US3839992A (en) * 1971-02-13 1974-10-08 Ricoh Kk Diazo type photosensitive sheet developing device
US3802389A (en) * 1971-04-30 1974-04-09 Iwasaki Kk Developing apparatus used in electrophotography
US3850662A (en) * 1971-09-10 1974-11-26 Kalle Ag Electrophotographic developing process and apparatus
US3722018A (en) * 1971-11-08 1973-03-27 Xerox Corp Cleaning apparatus
US3831552A (en) * 1972-02-07 1974-08-27 Identicator Corp Fingerprinting apparatus
US3865080A (en) * 1973-01-17 1975-02-11 Xerox Corp Toner pickoff apparatus
US3927641A (en) * 1973-05-10 1975-12-23 Fuji Xerox Co Ltd Developing mechanism using magnetic brush
JPS503344A (de) * 1973-05-10 1975-01-14
US3923004A (en) * 1973-12-27 1975-12-02 Xerox Corp Development and cleaning apparatus for reverse path machine
US3920329A (en) * 1974-09-25 1975-11-18 Xerox Corp Background removal apparatus
US4073266A (en) * 1975-02-20 1978-02-14 Hoechst Aktiengesellschaft Apparatus for developing a latent electrostatic image on an electrophotographic copying material
US4210448A (en) * 1975-10-21 1980-07-01 Elfotec A.G. Process for electrophotographic image formation and transfer
US4102306A (en) * 1976-05-31 1978-07-25 Konishiroku Photo Industry Co., Ltd. Developing roller and rinsing device
US4194466A (en) * 1976-11-12 1980-03-25 Hoechst Aktiengesellschaft Electrophotographic apparatus for developing latent electrostatic charge images
DE2816501A1 (de) * 1977-04-18 1978-10-19 Du Pont Bepulverungsvorrichtung zum aufbringen von magnetisch anziehbaren tonerteilchen
US4641956A (en) * 1980-08-25 1987-02-10 Xerox Corporation Extended nip cleaning system
DE3228094A1 (de) * 1981-08-01 1983-02-17 Konishiroku Photo Industry Co., Ltd., Tokyo Vorrichtung zum entwickeln eines elektrostatischen bildes
US4493882A (en) * 1982-11-29 1985-01-15 Canon Kabushiki Kaisha Image formation method and apparatus
US4764448A (en) * 1985-04-05 1988-08-16 Mitsubishi Chemical Industries, Ltd. Amorphous silicon hydride photoreceptors for electrophotography, process for the preparation thereof, and method of use

Also Published As

Publication number Publication date
BE722012A (de) 1969-04-08
DE1797462C3 (de) 1979-05-31
GB1210020A (en) 1970-10-28
DE1797462B2 (de) 1978-09-28
NL6814450A (de) 1969-04-11
DE1797462A1 (de) 1971-09-16
FR1585564A (de) 1970-01-23
AT287494B (de) 1971-01-25

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