US3637306A - Copying system featuring alternate developing and cleaning of successive image areas on photoconductor - Google Patents

Copying system featuring alternate developing and cleaning of successive image areas on photoconductor Download PDF

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Publication number
US3637306A
US3637306A US94262A US3637306DA US3637306A US 3637306 A US3637306 A US 3637306A US 94262 A US94262 A US 94262A US 3637306D A US3637306D A US 3637306DA US 3637306 A US3637306 A US 3637306A
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United States
Prior art keywords
photoconductor
developer
cleaning
image areas
cleaner unit
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US94262A
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English (en)
Inventor
Leon M Cooper
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International Business Machines Corp
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International Business Machines 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
    • G03G15/09—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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/28—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning
    • G03G15/30—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning in which projection is formed on a drum
    • G03G15/307—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which projection is obtained by line scanning in which projection is formed on a drum with more than one photoconductor revolution for each copying cycle
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
    • G03G21/0047—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium using electrostatic or magnetic means; Details thereof, e.g. magnetic pole arrangement of magnetic devices
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
    • G03G2221/0005—Cleaning of residual toner

Definitions

  • ABSTRACT Electrophotographic copying apparatus has charging, imaging, transferring, precleaning, and erasing facilities in a conventional sense but incorporates a combined developingcleaning unit that is operable to perform either function at the proper time during the copying sequence.
  • a first version incorporates a photoconductor drum structure surrounded with the necessary electrophotographic elements including a single magnetic brush developer-cleaner unit, the drum structure preferably having an odd number of image areas, such as three.
  • Another version incorporates a photoconductor belt also having provision for an odd number of image areas and movable past the stations. For single copy operation, alternate image positions are used for copying with cleaning occurring on the positions between. With the operator changing masters, this delay is not noticeable.
  • the throughput rate is half of the continuous copy rate.
  • every image position is used and cleaning is suspended until the end of the run at which time a full cycle cleaning operation is initiated. If the run is long and the copy degrades, intermediate cleanup cycles can be included as often as necessary.
  • a magnetic brush element forms a contacting surface for conveying toner onto the photoconductor surface during developing and away from the photoconductor surface during cleaning. Appropriate changes in biasing of the brush are made during operation.
  • BACKGROUND OF THE INVENTION AND PRIOR ART tive belt has an associated magnetic brush 24 operable at one station to develop images on the belt and at an independent second station to clean residual developer material from the belt. Broading shows no means for alternately activating a common magnetic brush that is in contact at a single station with a photoconductor medium and for applying an appropriate bias to the magnetic brush depending upon whether a developing mode or a cleaning mode is required.
  • electrophotographic apparatus having a photoconductor medium, such as a segmentized drum, is provided with the usual facilities for charging, imaging, developing, cleaning, transferring, precleaning, and erasing during the process of producing copies from an original document with the significant exception that a combined unit is provided in the apparatus for perfonning both the developing and cleaning functions in proper timed sequence with respect to the successive cycles of rotation of the medium and of the individual segments or frames thereon.
  • a photoconductor medium such as a segmentized drum
  • such combined unit incorporates a magnetic brush element with biasing means to establish appropriate biasing to initiate transfer of toner onto the photoconductor surface in the apparatus during the developing step and to attract residue residual toner from the photoconductor surface during the cleaning operation.
  • circuitry is also provided for effecting a cyclical sequence that establishes the most effective use of the structures during multiple cycle operation.
  • a magnetic drum photoconductor structure preferably has an odd number of segments, such as three segments or frames designated frame A, frame B, and frame C with timing of the various steps of the copying process being keyed into the rotation of the drum and the movement of the respective frames past the various stations during operation.
  • the first cycle of the drum includes imaging and developing of frame A and frame C and cleaning of frame B
  • the sequence involves cleaning of frames A and C and imaging of frame B. The sequencing described is continued in this manner during succeeding cycles of rotation of the drum.
  • another version of the invention contemplates a photoconductor belt structure'with the belt having, as an example, seven image areas along its longitudinal dimension. Imaging can be by a scanning technique or flashing of lamps to expose an entire image area at once. Operation with a belt photoconductor may be comparable to that noted for the drum structure with alternate imaging and cleaning of the frame or image areas on the belt. Further, each frame can be imaged during each and every complete cycle of movement of the belt with the cleaning taking place during a cycle such as the runout cycle or during another interval that is convenient. As will be described in detail, various combinations of biasing of the magnetic brush, toner particles, and developer mixture may be incorporated in the apparatus for the intended purpose.
  • the primary object of the present invention is to provide electrophotographic apparatus for producing copies from original documents wherein a number of functions required during the process are performed in timed sequence by a combined unitary portion of the apparatus operable as required during operation. 5
  • Still another object of the present invention is to provide an electrophotographic apparatus requiring the charging, imaging, developing, cleaning, transferring, precleaning, and erasing of images on a photoconductor surface and wherein at least the developing and cleaning functions are performed by a common portion of the apparatus,
  • Another object of the invention is to provide a magnetic brush developer-cleaner unit for an electrophotographic apparatus that performs both functions in the system when and as required.
  • an object of the invention is to provide a developingcleaning facility in an electrophotographic apparatus incorporating a magnetic brush element and having provision for appropriately biasing the brush to perform either a developing or a cleaning function during operation of the apparatus.
  • a further object of the invention is to provide a system of this nature with facilities for establishing timed sequences of electrophotographic steps enabling the alternate imaging and cleaning of image areas on a photoconductor surface to enable a sequence of developing followed immediately by cleaning.
  • an object of the present invention is to provide a system of this nature with provision for the production of a multitude of copies during an uninterrupted imaging sequence followed by a cleaning operation of all image areas on the photoconductor surface during the time not ordinarily used for copying purposes, such as runout time or other available time.
  • FIG. I DRAWINGS DETAILED DESCRIPTION First Embodiment with Photocondu ctor Drum, FIG. I
  • FIG. 1 a typical electrophotographic copying device is schematically shown in conjunction with an embodiment of the invention.
  • a cylindrical drum 21 having three segments or frames designated A, B, and C is mounted for rotation on a shaft.
  • Drum 21 has on its outer periphery 23 a photoconductive insulating layer which contains an organic or inorganic photoconductive material.
  • the drum 21 is rotated to bring the photoconductive layer to the various stations associated with the electrophotographic process.
  • a variety of photoconductive materials are suitable for use, for example, selenium, selenium-tellurium, anthracene, zinc oxide in a resin binder, etc.
  • a preexposure corona unit 35 deposits a charge on the photoconductive material while it is maintained in the dark.
  • a document 27 is held in place on a transparent plate 29, and an image of the document is projected on the surface of the photoconductive insulating layer by means of an illuminated scanning station 31 and optics 33.
  • the photoconductor is discharged at 37 in the portions struck by light to form the charged image corresponding to the document 27, and the image is developed at combined developer-cleaning station 38 which serves to bring finely divided charged toner particles into contact with the charged image on the surface of the photoconductive layer.
  • the developer station is preferably a magnetic brush developer unit that serves both as developer and cleaner in the system.
  • a two component developer composition is caused to move across the surface of the photoconductive layer.
  • the developer composition comprises relatively large carrier particles and relatively small heat fixable marking particles of toner.
  • the toner particles are attracted to and cling to the charged areas of the photoconductor layer.
  • the rotating photoconductive surface is contacted by a driven counterrotating cylindrical magnetic brush 49, whose length corresponds approximately to the width of the photoconductive layer on the drum, of the structure illustrated in FIGS. land 2.
  • the toner image on the surface of photoconductive layer 21 is transferred to a plain paper sheet or web 41 with the assistance of a toner transfer corona unit 43.
  • the paper is then separated from the photoconductive layer and passed to a heating unit 45 which acts to fix the toner image onto the paper.
  • the residual toner particles are loosened by the discharge of a preclean corona unit 47.
  • the sequencing of the various stations in the system is set up as follows:
  • FIG. 2 Second Embodiment with Photoconductor Belt, FIG. 2
  • FIG. 2 illustrates another embodiment of the invention where the electrophotographic apparatus incorporates a photoconductor belt movable in 'timed relation in the system to perform all of the various process steps in a manner comparable to that set forth previously in the table.
  • the apparatus of FIG. 2 incorporates a combined developingcleaning unit 17 that serves a function comparable to that in the drum-oriented system of FIG. 1.
  • the unit in FIG. 2 includes various electrophotographic facilities for producing copies. These include a charge corona station 18, the image plane 12a, previously mentioned, a developer-cleaning station 17, a transfer station 19, and a preclean corona station 20.
  • Belt 12 is mounted for movement as indicated by arrow 15 on drum driving elements 14 and 16.
  • a paper supply 11 accommodates a large quantity of individual sheets of paper that are fed by various devices including a belt 10 to the transfer station 19 for transfer of images in Following such transfer, the image is fused by a fuser, not shown, and transported to a completion station.
  • Sequencing of the developing-cleaning station 17 in the belt version of FIG. 2 may be comparable to the sequencing for the drum version of FIG. 1.
  • FIG. 3 is a suggested circuit for accomplishing the sequencing set forth in table A above. Depression of start button gates drum cycle circuit 62 that provides cycle 1, cycle 2, and cycle 3 outputs as shown. Rotation of drum 21 is recognized to provide timed impulses to drum cycle circuit 62 and frame circuit 63 that provides frame A, frame B, and frame C control signals as shown. Various AND and OR circuits at 65 are activated to gate the charge, image, develop, clean, transfer, and preclean and erase control blocks that are operable in sequence and that provide outputs on lines 67. If the photoconductor is erased as shown in table A, then the bias level for both developing and cleaning is normally the same. If the photoconductor is not erased and cleaning is desired then the bias must be altered by control circuit 50 to insure that it is more negative than the residual image remaining on the photoconductor.
  • frames occurs in an alternate fashion throughout the various cycles of rotation of drum structure 21.
  • frames A and C are imaged during drum cycle 1 while frame B is cleaned;
  • frame B is imaged during drum cycle 2 while frames A and C are cleaned.
  • the optical scanning system is imaging of frames and cleaning of With the embodiment of FIG. 1 and the sequencing shown, ,cleaning of image areas, that is, frames A, B, etc., on the surface of drum 21 occurs in the cycle of rotation of drum 2] immediately following the imaging and developing of the frame in question.
  • Electrophntographic apparatus for producing at least one copy from an original document and having the customary electrophotographic facilities for charging. imaging. transfer ring. precleaning. and erasing a photoconductor medium. said photoconductor medium comprising a movable member havduring joperation of said apparatus. compnsmg:-
  • a combined developer-cleaner unit positioned for engagement with said photoconductor medium at a single station for developing an image in one mode and cleaning said photoconductor medium in another mode;
  • the preclean/erase station may be optional. Without it, the
  • developer bias would have to be switched to a value below the cleaner without changing the bias.
  • sequencing means for activating said developer-cleaner unit to alternately develop and clean successive image areas during rotation of said drum member.
  • runout means operable upon termination of said successive cycles and production of a multitude of copies to activate said developer-cleaner unit to clean said photoconductor drum member copy run.
  • said photoconductor medium is in the form of an endless belt member mounted for movement in a preferred direction to convey image areas past the various stations in said apparatus during operation;
  • said developer-cleaner unit comprises a housing to accommodate a developer mixture including tonenand further comprising:
  • a magnetic brush mounted within said housing and in contact with saidphotoconductor medium at a single station for conveying developer mixture onto said photocond uctor medium in one mode for the purpose of developing images on said photoconductor medium and for applying developer mixture onto said photoconductor medium in a in readiness for a succeeding multiplescavenging mode for the photoconductor medium;
  • sequencing means for activating said developer-cleaner unit and said magnetic brush member in the appropriate mode required during operation of said apparatus.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Cleaning In Electrography (AREA)
US94262A 1970-12-02 1970-12-02 Copying system featuring alternate developing and cleaning of successive image areas on photoconductor Expired - Lifetime US3637306A (en)

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US9426270A 1970-12-02 1970-12-02

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US (1) US3637306A (it)
JP (1) JPS5033863B1 (it)
BE (1) BE775464A (it)
CA (1) CA944011A (it)
FR (1) FR2117090A5 (it)
IT (1) IT940751B (it)

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736055A (en) * 1971-12-17 1973-05-29 Ibm Reproduction apparatus incorporating alternate redevelopment and reimaging cycles for multiple copies
DE2318839A1 (de) * 1972-04-13 1973-10-18 Canon Kk Elektrophotographische vorrichtung
US3819262A (en) * 1972-07-13 1974-06-25 Scm Corp Cleaning means for an overcoated photoconductive surface
US3865080A (en) * 1973-01-17 1975-02-11 Xerox Corp Toner pickoff apparatus
US3893416A (en) * 1973-12-27 1975-07-08 Xerox Corp Development and cleaning apparatus for reverse path machine
US3924567A (en) * 1973-12-17 1975-12-09 Pitney Bowes Inc Apparatus and process for developing electrostatic
USRE29179E (en) * 1971-12-17 1977-04-12 International Business Machines Corporation Reproduction apparatus incorporating alternate redevelopment and reimaging cycles for multiple copies
US4077711A (en) * 1974-05-28 1978-03-07 Ricoh Company, Ltd. Electrophotographic copying apparatus of wet developing type
US4108658A (en) * 1974-03-11 1978-08-22 Oce-Van Der Grinten N.V. Process for developing electrostatic latent images
US4181422A (en) * 1976-05-17 1980-01-01 Elfotec A.G. Process and apparatus for developing and cleaning a charge image carrier
US4190464A (en) * 1971-06-03 1980-02-26 Canon Kabushiki Kaisha Method for cleaning a photoconductive surface with liquid toner
US4201465A (en) * 1975-11-26 1980-05-06 Ricoh Company, Ltd. Drum cleaning process and apparatus for electrophotography
DE2947981A1 (de) * 1978-11-28 1980-05-29 Ricoh Kk Elektrostatisches kopiergeraet
US4205912A (en) * 1975-11-11 1980-06-03 Tokyo Shibaura Electric Company Limited Electrophotographic apparatus
US4240723A (en) * 1974-05-20 1980-12-23 Elfotec A.G. Process for electrographic image production and an apparatus for carrying out this process
US4264183A (en) * 1979-06-04 1981-04-28 Eastman Kodak Company Duplex copying apparatus and method
US4265998A (en) * 1979-11-13 1981-05-05 International Business Machines Corporation Electrophotographic photoreceptive background areas cleaned by backcharge process
US4320958A (en) * 1980-10-27 1982-03-23 Xerox Corporation Combined processing unit
US4350750A (en) * 1976-01-23 1982-09-21 Ricoh Company, Ltd. Electrophotographic process
EP0068624A1 (en) * 1981-06-29 1983-01-05 Xerox Corporation An electrophotographic printing machine
US4420242A (en) * 1982-03-05 1983-12-13 Hitachi Metals, Ltd. Magnetic brush developing and cleaning process
US4426151A (en) 1980-12-23 1984-01-17 Canon Kabushiki Kaisha Cleaning device for cleaning an image bearing member with developer
US4456673A (en) * 1981-03-24 1984-06-26 Mita Industrial Co., Ltd. Transfer-type electrostatic copying method
US4457614A (en) * 1981-07-21 1984-07-03 Mita Industrial Co., Ltd. Electrostatic copying apparatus
US4465360A (en) * 1981-03-31 1984-08-14 Sharp Kabushiki Kaisha Electrophotographic copying machine
US4488802A (en) * 1982-01-14 1984-12-18 Fuji Xerox Co., Ltd. Electrophotographic device with single stations serving multiple functions
US4500198A (en) * 1982-12-10 1985-02-19 International Business Machines Corporation Multiple roller magnetic brush developer having development electrode voltage switching
US4515465A (en) * 1980-04-15 1985-05-07 Mita Industrial Company Limited Electrostatic copying apparatus
US4544260A (en) * 1984-05-25 1985-10-01 Xerox Corporation Removable processing cartridge for electrostatographic reproducing apparatus
US4547064A (en) * 1984-08-31 1985-10-15 Xerox Corporation Electrostatographic reproducing apparatus
US4556308A (en) * 1984-05-25 1985-12-03 Xerox Corporation Removable processing cartridge for electrostatographic reproducing apparatus
US4572655A (en) * 1983-07-25 1986-02-25 Ricoh Systems, Inc. Electrophotographic copying apparatus and method of use including electrostatic toner recycling procedure
US4589759A (en) * 1984-08-31 1986-05-20 Xerox Corporation Reproducing apparatus with optic scanning module
US4616922A (en) * 1985-04-05 1986-10-14 Minnesota Mining And Manufacturing Company Electrophotographic copying apparatus and process
US4652114A (en) * 1985-04-05 1987-03-24 Minnesota Mining And Manufacturing Company Electrophotographic copying apparatus and process
US4814822A (en) * 1987-06-08 1989-03-21 Xerox Corporation Method and apparatus for automatic "two-up" copying with intermediate latent image copiers
US5229825A (en) * 1991-12-02 1993-07-20 Eastman Kodak Company Magnetic brush laydown/pickup apparatus
US20050214039A1 (en) * 2004-03-29 2005-09-29 Eastman Kodak Company Synchronous duplex printing systems

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2874063A (en) * 1953-03-23 1959-02-17 Rca Corp Electrostatic printing
US2911330A (en) * 1958-04-11 1959-11-03 Haloid Xerox Inc Magnetic brush cleaning
US2986442A (en) * 1956-07-19 1961-05-30 Century Geophysical Corp Electrophotographic oscillograph for observing slow recurrent signals
US3572923A (en) * 1968-08-26 1971-03-30 Xerox Corp Cleaning method and apparatus for electrostatic copying machines
US3580673A (en) * 1968-08-26 1971-05-25 Xerox Corp Cleaning apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2874063A (en) * 1953-03-23 1959-02-17 Rca Corp Electrostatic printing
US2986442A (en) * 1956-07-19 1961-05-30 Century Geophysical Corp Electrophotographic oscillograph for observing slow recurrent signals
US2911330A (en) * 1958-04-11 1959-11-03 Haloid Xerox Inc Magnetic brush cleaning
US3572923A (en) * 1968-08-26 1971-03-30 Xerox Corp Cleaning method and apparatus for electrostatic copying machines
US3580673A (en) * 1968-08-26 1971-05-25 Xerox Corp Cleaning apparatus

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4190464A (en) * 1971-06-03 1980-02-26 Canon Kabushiki Kaisha Method for cleaning a photoconductive surface with liquid toner
US3736055A (en) * 1971-12-17 1973-05-29 Ibm Reproduction apparatus incorporating alternate redevelopment and reimaging cycles for multiple copies
USRE29179E (en) * 1971-12-17 1977-04-12 International Business Machines Corporation Reproduction apparatus incorporating alternate redevelopment and reimaging cycles for multiple copies
DE2318839A1 (de) * 1972-04-13 1973-10-18 Canon Kk Elektrophotographische vorrichtung
US3819262A (en) * 1972-07-13 1974-06-25 Scm Corp Cleaning means for an overcoated photoconductive surface
US3865080A (en) * 1973-01-17 1975-02-11 Xerox Corp Toner pickoff apparatus
US3924567A (en) * 1973-12-17 1975-12-09 Pitney Bowes Inc Apparatus and process for developing electrostatic
US3893416A (en) * 1973-12-27 1975-07-08 Xerox Corp Development and cleaning apparatus for reverse path machine
US4108658A (en) * 1974-03-11 1978-08-22 Oce-Van Der Grinten N.V. Process for developing electrostatic latent images
US4240723A (en) * 1974-05-20 1980-12-23 Elfotec A.G. Process for electrographic image production and an apparatus for carrying out this process
US4077711A (en) * 1974-05-28 1978-03-07 Ricoh Company, Ltd. Electrophotographic copying apparatus of wet developing type
US4205912A (en) * 1975-11-11 1980-06-03 Tokyo Shibaura Electric Company Limited Electrophotographic apparatus
US4201465A (en) * 1975-11-26 1980-05-06 Ricoh Company, Ltd. Drum cleaning process and apparatus for electrophotography
US4350750A (en) * 1976-01-23 1982-09-21 Ricoh Company, Ltd. Electrophotographic process
US4181422A (en) * 1976-05-17 1980-01-01 Elfotec A.G. Process and apparatus for developing and cleaning a charge image carrier
DE2947981A1 (de) * 1978-11-28 1980-05-29 Ricoh Kk Elektrostatisches kopiergeraet
US4264183A (en) * 1979-06-04 1981-04-28 Eastman Kodak Company Duplex copying apparatus and method
US4265998A (en) * 1979-11-13 1981-05-05 International Business Machines Corporation Electrophotographic photoreceptive background areas cleaned by backcharge process
US4515465A (en) * 1980-04-15 1985-05-07 Mita Industrial Company Limited Electrostatic copying apparatus
US4320958A (en) * 1980-10-27 1982-03-23 Xerox Corporation Combined processing unit
US4426151A (en) 1980-12-23 1984-01-17 Canon Kabushiki Kaisha Cleaning device for cleaning an image bearing member with developer
US4456673A (en) * 1981-03-24 1984-06-26 Mita Industrial Co., Ltd. Transfer-type electrostatic copying method
US4465360A (en) * 1981-03-31 1984-08-14 Sharp Kabushiki Kaisha Electrophotographic copying machine
EP0068624A1 (en) * 1981-06-29 1983-01-05 Xerox Corporation An electrophotographic printing machine
US4457614A (en) * 1981-07-21 1984-07-03 Mita Industrial Co., Ltd. Electrostatic copying apparatus
US4488802A (en) * 1982-01-14 1984-12-18 Fuji Xerox Co., Ltd. Electrophotographic device with single stations serving multiple functions
US4420242A (en) * 1982-03-05 1983-12-13 Hitachi Metals, Ltd. Magnetic brush developing and cleaning process
US4500198A (en) * 1982-12-10 1985-02-19 International Business Machines Corporation Multiple roller magnetic brush developer having development electrode voltage switching
US4572655A (en) * 1983-07-25 1986-02-25 Ricoh Systems, Inc. Electrophotographic copying apparatus and method of use including electrostatic toner recycling procedure
US4544260A (en) * 1984-05-25 1985-10-01 Xerox Corporation Removable processing cartridge for electrostatographic reproducing apparatus
US4556308A (en) * 1984-05-25 1985-12-03 Xerox Corporation Removable processing cartridge for electrostatographic reproducing apparatus
US4547064A (en) * 1984-08-31 1985-10-15 Xerox Corporation Electrostatographic reproducing apparatus
US4589759A (en) * 1984-08-31 1986-05-20 Xerox Corporation Reproducing apparatus with optic scanning module
US4616922A (en) * 1985-04-05 1986-10-14 Minnesota Mining And Manufacturing Company Electrophotographic copying apparatus and process
US4652114A (en) * 1985-04-05 1987-03-24 Minnesota Mining And Manufacturing Company Electrophotographic copying apparatus and process
US4814822A (en) * 1987-06-08 1989-03-21 Xerox Corporation Method and apparatus for automatic "two-up" copying with intermediate latent image copiers
US5229825A (en) * 1991-12-02 1993-07-20 Eastman Kodak Company Magnetic brush laydown/pickup apparatus
US20050214039A1 (en) * 2004-03-29 2005-09-29 Eastman Kodak Company Synchronous duplex printing systems
US7469119B2 (en) * 2004-03-29 2008-12-23 Eastman Kodak Company Synchronous duplex printing systems with intermediate transfer members

Also Published As

Publication number Publication date
JPS5033863B1 (it) 1975-11-04
IT940751B (it) 1973-02-20
FR2117090A5 (it) 1972-07-21
CA944011A (en) 1974-03-19
BE775464A (fr) 1972-03-16

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