US3702483A - Color rendition method - Google Patents

Color rendition method Download PDF

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Publication number
US3702483A
US3702483A US100982A US3702483DA US3702483A US 3702483 A US3702483 A US 3702483A US 100982 A US100982 A US 100982A US 3702483D A US3702483D A US 3702483DA US 3702483 A US3702483 A US 3702483A
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United States
Prior art keywords
color
image
potential
recorded
developed
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Expired - Lifetime
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US100982A
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English (en)
Inventor
Joseph Fantuzzo
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Xerox Corp
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Xerox Corp
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    • 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
    • G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
    • G03G15/0818—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the structure of the donor member, e.g. surface properties
    • 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
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0105—Details of unit
    • G03G15/0121—Details of unit for developing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0167—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member
    • G03G2215/017—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member single rotation of recording member to produce multicoloured copy
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0167—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member
    • G03G2215/0187—Multicoloured toner image formed on the recording member
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/04—Arrangements for exposing and producing an image
    • G03G2215/0495—Plural charge levels of latent image produced, e.g. trilevel
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0602—Developer
    • G03G2215/0604—Developer solid type
    • G03G2215/0614—Developer solid type one-component
    • G03G2215/0619—Developer solid type one-component non-contact (flying development)
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0634—Developing device
    • G03G2215/0636—Specific type of dry developer device
    • G03G2215/0641—Without separate supplying member (i.e. with developing housing sliding on donor member)
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • each 355/4 developing u'nit has an electrical control means opera- 8 15/04 3 15/08 tively 'associated therewith to control development whereby only color components recorded at or above 17854 CD a predetermined potential are developed within the unit.
  • the recorded images are developed in a descend- References C'ted ing order of magnitude whereby different and distinct colors are produced for each color component UNITED STATES PATENTS recorded on the photoconductive element.
  • the final 3,045,644 7/ 1962 schwel'tz 346/ 74 ES X color rendition is transferred, in a single operation, to
  • JosE xm Uz'zo AT7DRNEY COLOR RENDITION METHOD This invention relates co color copying and, in particular to a simple and efficient means for producing color copy. I More specifically this invention relates to a color process suitable for use in xerography. Basically, in conventional xerography, a photosensitiveplate, consisting of a photoconductive coating placed upon a conductive backing, is'uniformly charged and the plate then exposed to a light image containing original subject matter to be reproducediUnder the influence of the light image, the charge on the photoconductive member is selectively dissipated in the light struckregions thereby producing a latent electrostatic image of the original.
  • the charged latent electrostatic image is then developed, or made visible, by bringing oppositely charged,finely divided, electroscopic marking particles into operative communication with the plate in a manner so that the charge particles are attracted into the imaged regions.
  • the visible image is transferred to a final support material, such as paper or the like, and the image affixed thereto to form a permanent record of the original.
  • the basic xerographic process can be adapted to produce full color reproductions by using well known subtractive color printing techniques. "It is conventional, in the xerographic subtractive system, to first color separate the originalinto the primary color components of red, greenand blue. Each component is then used to recorda separate latent electrostatic image on the surface of a photoconductive plate and thefimages are developed using toners containing colorants that are the complements of the primary colors recorded. The. recorded red, green and blue color components are developed with toner containing .the colorants of cyan, magenta and yellow. Each developed image is individually transferred to a sheet of final support material to create a full color rendition of the original. Because of inherent limitations found in most known colorants, it is generally necessary to employ costly and complex masking and/or balancing techniques to achieve a faithful color reproduction. Furthermore, because of the number of exposure and transfer operations involved, registration is also a problem in this type of system.
  • a further object of this invention is to reduce the number of processing steps required to produce a colo copy.
  • a still further object of this invention is to eliminate the need for special recording means when xerographically reproducing a color copy. Yet another object of this invention is to minimize color contamination in a xerographic color copying device. .7
  • Still furtherobject of this invention is to provide a color copier capable of I rapidly and efiiciently reproducing functional colors.
  • an automatic reproducing device adapted to continually pass a photoconductive plate through a series of processing stations.
  • An original, containing discernable color information is usedto expose the uniformly charged photoconductive plate whereby each color component found in the original is recorded at a discrete charge potential.
  • the plate is object of this invention to simplify then passed through a developing station containing a smaller toner particles are applied to the sheet and" plurality of developing units equal in number to the number of discernable colors found in the original.
  • Electrical control means are operatively associated with each of the developing units so that only color components recorded at or above apredetermined potential are developed within the unit.
  • the recorded images are developed in .a descending order of magnitude whereby different and distinct colors are produced fir each color component recorded on the photosensitive element.
  • FIG. 1 is a schematic view in perspective showing an automatic xerographic reproducing machine embodying the teachings of the present invention
  • FIG. 2 is an enlarged end view, in partial section, illustrating one of the developer units employed in the apparatus shown in FIG. 1;
  • FIG. 3 is a partial sectional view illustrating the construction of the donor roll employed in the developing instant invention is well suited for use in a wide variety of applications and the teachings herein embodied are not necessarily restricted to the particular machine environment disclosed.
  • the xerographic reproducing apparatus employs a rotatably mounted drum having a photoconductive surface 11 thereon.
  • the photoconductor is preferably formed of a photosensitive material that exhibits a relatively panchromatic response to visible light.
  • the drum is arranged to move in the direction indicated to transport the photoconductive surface thereon sequentially through a series of processing stations.
  • the first processing station in the direction of drum rotation is a charging station A containing a corona generator 12 similar to that disclosed by Vyverberg in U.S. Pat. No. 2,836,725.
  • the corona generator is arranged to extend transversely across the drum and serves to uniformly charge to a relatively high potential, the photoconductive surface thereon.
  • the charged photoconductive surface is next transported through an exposure station 13 including a moving lens 15 interposed between an object mirror 16 and an image mirror 17.
  • the original input scene information which is in this case carried upon an original document 18, is stationarily supported upon a viewing platen l9 and successive incremental areas thereon illuminated by means of a moving lamp assembly 20.
  • the brush fibers into moving contact with the drum surface to remove residual toner particles found thereon after the transfer operation.
  • the lens element 15 is adapted to scan the illuminated areas and to focus the reflected light image therefrom through the mirror system onto the moving photoconductive drum whereby the drum is imaged.
  • each of the developing units is arranged to apply a toner containing a predetermined colorant to the imaged drum surface to develop the recorded original input scene information.
  • the now visible image is moved to a transfer station D wherein the image is transferred electrostatically to a web 27 of final support material by means of a conventional transfer corotron 28 similar to that disclosed in the previously mentioned Vyverberg patent.
  • the web of final support material is transported through the transfer station at the same peripheral speed as the moving drum surface by means of the cooperating feed roll as provided to prevent the image from being smeared.
  • the image bearing web of final support material is transported through an image fixing station E.
  • the sheet is delivered between the nip of a pair of cooperating roll members which coact to deliver sufficient heat and pressure energy to fix the color toner images to the support sheet.
  • the heat pressure fixing device disclosed herein is similar to that described by Hudson in U.S. Pat. No. 3,256,002.
  • the last processing station in the direction of drum rotation is a drum cleaning station F wherein a rotatably mounted fibrous member 30 is positioned adjacent to the photoconductive surface.
  • the brush is arranged to rotate in the direction indicated so as to drag providing relatively low background development in orderto minimize color contamination.
  • backgroun refers to those areas in the original containing no input scene information. Inadvertantly, unwanted toner particles are sometimes randomly deposited in these background areas during development which results in dirty or poor quality copy being produced. In a multi-color system, as hereindisclosed, background development leads to color contamination.
  • a transfer development technique is employed in the preferred embodiment of the present invention.
  • transfer development a uniform layer of finely divided toner material is first coated upon the surface of a donor member and the member brought into operative communication with the image bearing photoconductive element.
  • the photoconductor and the donor are separated from each other within the development zone by means of a finite air gap.
  • the air gap is of a sufficient width' to prevent the toner particles supported on the donor member from contacting the photoconductive surface as the members move through the development zone.
  • This out-of-contact development is regions is the electrostaticforce field associated with the latent electrostatic images. Consequently, little or no toner is inadvertently deposited in the background areas.
  • the developing mechanism typically contained within each of 'the' developing units 25 and 26.
  • the individual toner particles are initially uniformly loaded upon a cylindrical donor member 40 and the donor moved continuously adjacent to the photoconductive drum surface 10 through a development zone 63.
  • the donor member and the photoreceptor are positioned so that they are separated by a finite air gap 42', the air gap being typically within a range of between 0.001 and 0.010 inches.
  • the donor member is basically formed of a plurality of longitudinally extended segments 41 as illustrated in FIG. 3. Each segment is electrically isolated from the other by means of dielectric strips 44 whereby each segment is capable of independentally supporting a discrete charge potential thereon. Each segment is formed upon a conductive metallic substrate 46, preferably being of aluminum, over which is placed a thin dielectric enamel coating 47. A conductive grid network 48, in turn, is placed over the insulating coating in a manner wherein the outer surface of each segment is broken into a multitude of discrete dielectric islands 49 surrounded by the conductive grid material.
  • each of the segmented conductive sub strates 46 are connected, via electrical connector'50, to a biasing source (not shown) and the substrates placed at a reference potential which, in this case, is a ground ing zone 64.
  • a biasing source not shown
  • the donor roll is passed through the toner loading and agglomerate removal zone 45 in which is potential.
  • control means 51 consists of a series of commutators mounted upon governed by means of a biasing source '55, acting through wire 56 and brushes 57, which serves to place the grid segments passing therethrough at a predeterv mined potential.
  • thesegmented'donor rollmember is arranged to pass through five distinct electrical regions. These regions include, v(1) a toner loadingand agglomerate removing zone 60, (2) a toner somewhere between +100 and +200 volts.
  • regions include, v(1) a toner loadingand agglomerate removing zone 60, (2) a toner somewhere between +100 and +200 volts.
  • the outer periphery of dummy roll 70 is supported a distance equal to air gap 42 from the rolland the segmented grids passing through this region are placed at approximately the same potential as applied thereto within the development zone 63.
  • the housing is adapted to place a quantity of negatively charged toner particles in contact with the surface of the moving donor member.
  • the grid segments passing through this electrical region are placed at a relatively high bias potential, approximately +350 volts' so that the donor roll attracts and supports, in a charged state thereon, a layer of toner a relative uniform toner coating. It has been found that surface protrusions in the toner layer cause unwanted background development and thus degradethe quality of development.
  • a toner charging zone 61 Located between the vacuum means andthe development zone 63 is a toner charging zone 61 wherein the bias on the donor gn'd'is reduced to a reference or ground potential.
  • a corona generator 69 that is adapted to spray a uniform negative corona charge upon the toner particles supported on the donor roll surface whereby each toner particle is placed at substantially the same charge level. Controlling the uniformity of the toner coating and the uniformity of charge on the toner particles places the developing system in a condition then presented to the imaged photoconductive surface within the development zones 63 wherein transfer development is accomplished.
  • the potential applied to the donor grid within this electrical region is such as to hold the threshold potential, that is,'the potential at which toner particles supported on the donor member are both activated andattracted into the imaged areas on the drum surface, at a predetermined level.
  • the residual ,toner remaining thereon is transported on the donor roll surface to the donor roll cleaning zone 64.
  • donor grid potential is reducedto the reference or' ground level and the donor roll surface'treated with corona from AC corona generator 75.
  • the AC corona generator serves toneutralize the charge on the toner particles. After neutralization the residual toner is readily swept from the 'donor'roll surface by means of a brush member 76, and the removed toner particles exhausted from the system.
  • the original 18 to be reproduced' is placed upon the viewing platen 19(FlG. 1) and the rotated'photoconducting drum surface exposed to a flowing light image of the information contained therein.
  • the original document preferably contains colors or hues that are capable of selectively discharging the photoconductive whereby background development is held to a minimum.
  • a biased dummy roll member 70 preferably having a. relatively smooth surface is arranged to be conveniently rotated at approximately the same peripheral speed of the donor roll member.
  • the roll is biased, by means of a suitable biasing source 71,
  • the photoconductor will be discharged to a greater degree in those regions irradiated by light reflected from the original containing less dense, orlight, colors and to a lesser degree by the reflected dark colors.
  • Black images are therefore generally recorded as latent images having the greatest charge density.
  • the white images'are recorded at a relatively low charge density and theother colors will range somewhere between the blacks and whites.
  • the ,photoconductor upon exposure, records the input scene information at two distinct charge levels with each charge corresponding to a color found in the original. In effect, therefore, the input scene information recorded on the photoreceptor contains both input scene information'and color information.
  • those images recorded at the higher image potential are developed first with a toner material containing a first colorant while the images recorded at the lower potential level are developed next employing a toner containing a second colorant.
  • Developer units 25 and 26 employing the transfer development" apparatus herein described, are provided for this purpose.
  • Developer unit 25 which is arranged to initially act upon the rotating photoconductive drum surface, applies toner material of a first color into the more highly charged imaged areas. To accomplish this result, the
  • the images recorded at the higher potential be developed using a black toner while the images recorded at the lower image potential be developed using a toner containing one of the primary colors, as for example, red, 'blue, green or the like.
  • a toner containing one of the primary colors as for example, red, 'blue, green or the like.
  • This may of course result in some of the toner of a primary color being deposited activation and attraction of toner particlesfrom the donor member into the imaged areas.
  • the grid of the donor roll so biased that is, at a potential greater than the lower recorded image potentials, the images recorded at a higher potential will be developed to a first color and the images recorded at a lower potential will remain undeveloped.
  • the operation of the first developer unit is graphically illustrated in FIG. 4. As shown, the dark or more Subsequent to the first development step, the image drum surface is advanced into a second developing unit 26-. Here, the bias potential placed on the grid of the donor roll is reduced to approximately the background potential on the photoconductor as the roll passes through the developing zone. Normally, background potential will vary somewhere between +100 and +200 volts.
  • the second developing unit is arranged to apply toner containing a second colorant to those imaged areas on the plate surface that are recorded at potentials higher than the background potential.
  • the second developing step is graphically illustrated in FIG. 5.
  • V bias potential
  • V background potential
  • V bias potential
  • a second mode of operation can be also employed in the practice of the present invention.
  • the two toner materials involved contain colorants capable of being subtractively mixed during the second developing operation to render two distinct color images in the final copy.
  • the first colorant applied tothe photoconductor could be a yellow toner which would then be overdeveloped during the next subsequent developing step with a magenta containing colorant to render a red.
  • references to either positive or negative potentials in this particular disclosure are considered as merely defining a relationship and it' should be clear that the teachings of the present invention can be practiced as long as these relationships are maintained.
  • each developed colorant is arranged to subtractively mix with other subsequently developed colorants to. produce a predetermined resultant color.
  • the method of claim 1 further including the step of simultaneously transferring the developed color components of the latent image to a final support material subsequent to the last development sequence.
  • Apparatus of thetype wherein a latent electrostatic image formulated on an image retaining element is developed by bringing oppositely'charged electroscopic marking particles of the same polarity into operative communication with said element, the apparatus including means to form an electrostatic latent image to record input scene information on said image retaining element comprising more than one color component recorded at discrete potential levels of the same polarity,
  • each unit being arranged to sequentially act upon the image retaining member to bring into operative communication therewith electroscopic marking powder of the same charge polarity containing a predetermined colorant corresponding to each color component and means to electrically regulate each developing unit 1 units are arranged to subtractively mixthe colorants to produce predetermined color in the composite image formed by the plurality of color components.
  • the apparatus of claim 5 further including means to simultaneously transfer the developed color components of the latent image to a final support material.
  • the apparatus of claim 7 further including means to fix the transfer color images to the fin'al support material.
  • the apparatus further includ means to expose the member to a light image to record latentelectrostatic images thereon at least at two discrete potential levels of the same polarity
  • first developing means to develop the latent electrostatic images recorded at the higher of the two potentiallevels to the exclusion of those images recorded at the lower potential levels using a first toner of like charge polarity containinga first colorant
  • second developing means to develop those images recorded at said lower potential level in the presence of the previously developed images using a second toner of the same charge polarity as said first toner containing asecond colorant;
  • fist and second developing means include a donor member uniformly coated with electroscopic marking particles and being arranged to move in close proximity with the image retaining element whereby the particles are transferred from said donor member to the imaged regions on said element, and
  • biasing means associated with said donor member to electrically regulate the development process to allow toner brought into operative association with said image retaining element to be attracted into imaged regions recorded at or above a predetermined potential.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Color Electrophotography (AREA)
US100982A 1970-12-23 1970-12-23 Color rendition method Expired - Lifetime US3702483A (en)

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Application Number Priority Date Filing Date Title
US10098270A 1970-12-23 1970-12-23

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US3702483A true US3702483A (en) 1972-11-07

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US (1) US3702483A (fr)
BE (1) BE777015A (fr)
CA (1) CA935334A (fr)
DE (1) DE2163591A1 (fr)
FR (1) FR2119655A5 (fr)
GB (1) GB1361647A (fr)
IT (1) IT944210B (fr)
NL (1) NL7117555A (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833293A (en) * 1973-07-20 1974-09-03 Xerox Corp Method of creating color transparencies
JPS5119441A (fr) * 1974-08-09 1976-02-16 Hitachi Ltd
US4063946A (en) * 1973-01-22 1977-12-20 Rank Xerox Ltd. Electrophotographic color reproduction process employing photoconductive material with dual light fatigue properties
US4068938A (en) * 1974-09-24 1978-01-17 Rank Xerox Ltd. Electrostatic color printing utilizing discrete potentials
US4078929A (en) * 1976-11-26 1978-03-14 Xerox Corporation Method for two-color development of a xerographic charge pattern
US4106870A (en) * 1973-12-28 1978-08-15 Canon Kabushiki Kaisha Color electrophotographic method and apparatus
US4188213A (en) * 1973-12-03 1980-02-12 Xerox Corporation Color corrected printing system
US4205322A (en) * 1976-04-27 1980-05-27 Nippon Electric Co., Ltd. Electrostatic method of simultaneously transferring to a recording medium a toner image having different polarities
US4264185A (en) * 1978-05-24 1981-04-28 Ricoh Co., Ltd. Two color electrostatographic apparatus
US4378415A (en) * 1981-10-13 1983-03-29 Xerox Corporation Color imaging, layered organic photoresponsive device having hole injection and transport layers, red sensitive layer and short wavelength sensitive layer
US4407917A (en) * 1978-08-28 1983-10-04 Ricoh Company, Ltd. Information image synthesizing and copying method
US4416533A (en) * 1978-12-19 1983-11-22 Hitachi, Ltd. Nonimpact printer
US4509850A (en) * 1983-08-08 1985-04-09 Xerox Corporation Two-color electrophotographic printing machine
US4510223A (en) * 1983-02-07 1985-04-09 Coulter Systems Corporation Multicolor electrophotographic imaging process
US4803518A (en) * 1984-07-06 1989-02-07 Konishiroku Photo Industry Co., Ltd. Apparatus for forming a multi-color toner image
US4839692A (en) * 1984-09-06 1989-06-13 Konishiroku Photo Industry Co., Ltd. Apparatus for reproducing multi-color image
US4847655A (en) * 1987-12-11 1989-07-11 Xerox Corporation Highlight color imaging apparatus
US4901100A (en) * 1988-08-18 1990-02-13 Xerox Corporation Single pass color highlighting copying system
US4947200A (en) * 1988-05-19 1990-08-07 Hitachi, Ltd. Developing device and multi-color recording apparatus
US4970536A (en) * 1984-07-27 1990-11-13 Konishiroku Photo Industry Co., Ltd. Apparatus for multicolor image forming wherein image forming conditions are adjusted based on reference images
US5317373A (en) * 1992-12-23 1994-05-31 Xerox Corporation Method and apparatus for user customized colorants in an electrophotographic printing machine

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FR2208142B1 (fr) * 1972-11-22 1980-07-11 Canon Kk
US3983815A (en) * 1975-01-29 1976-10-05 Honeywell Information Systems, Inc. Apparatus and method for printing on plain paper
JPS6028351B2 (ja) * 1977-10-13 1985-07-04 株式会社リコー ２色電子写真複写装置
JPS5911113B2 (ja) * 1979-04-20 1984-03-13 富士通株式会社 電子写真式記録装置
US4599285A (en) * 1983-10-03 1986-07-08 Konishiroku Photo Industry Co., Ltd. Multiplex image reproducing method

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US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US3045644A (en) * 1957-06-06 1962-07-24 Xerox Corp Two-color electrostatic printing apparatus
US3060020A (en) * 1958-03-20 1962-10-23 Rca Corp Method of electrophotographically producing a multicolor image

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US3045644A (en) * 1957-06-06 1962-07-24 Xerox Corp Two-color electrostatic printing apparatus
US3060020A (en) * 1958-03-20 1962-10-23 Rca Corp Method of electrophotographically producing a multicolor image

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4063946A (en) * 1973-01-22 1977-12-20 Rank Xerox Ltd. Electrophotographic color reproduction process employing photoconductive material with dual light fatigue properties
US3833293A (en) * 1973-07-20 1974-09-03 Xerox Corp Method of creating color transparencies
US4188213A (en) * 1973-12-03 1980-02-12 Xerox Corporation Color corrected printing system
US4106870A (en) * 1973-12-28 1978-08-15 Canon Kabushiki Kaisha Color electrophotographic method and apparatus
JPS5119441A (fr) * 1974-08-09 1976-02-16 Hitachi Ltd
JPS5533063B2 (fr) * 1974-08-09 1980-08-28
US4068938A (en) * 1974-09-24 1978-01-17 Rank Xerox Ltd. Electrostatic color printing utilizing discrete potentials
US4205322A (en) * 1976-04-27 1980-05-27 Nippon Electric Co., Ltd. Electrostatic method of simultaneously transferring to a recording medium a toner image having different polarities
US4078929A (en) * 1976-11-26 1978-03-14 Xerox Corporation Method for two-color development of a xerographic charge pattern
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Also Published As

Publication number Publication date
CA935334A (en) 1973-10-16
IT944210B (it) 1973-04-20
GB1361647A (en) 1974-07-30
DE2163591A1 (de) 1972-07-13
NL7117555A (fr) 1972-06-27
BE777015A (fr) 1972-06-21
FR2119655A5 (fr) 1972-08-04

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