US3778148A - Apparatus and method for selectively discharging the photoconductive surface of an electrostatic drum copier to facilitate the cleaning thereof - Google Patents

Apparatus and method for selectively discharging the photoconductive surface of an electrostatic drum copier to facilitate the cleaning thereof Download PDF

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Publication number
US3778148A
US3778148A US00317779A US3778148DA US3778148A US 3778148 A US3778148 A US 3778148A US 00317779 A US00317779 A US 00317779A US 3778148D A US3778148D A US 3778148DA US 3778148 A US3778148 A US 3778148A
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US
United States
Prior art keywords
transfer medium
length
photoconductive member
copying machine
photoconductive
Prior art date
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
Application number
US00317779A
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English (en)
Inventor
K Fujitsuka
K Honda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujifilm Business Innovation Corp
Original Assignee
Fuji Xerox Co Ltd
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Filing date
Publication date
Application filed by Fuji Xerox Co Ltd filed Critical Fuji Xerox Co Ltd
Application granted granted Critical
Publication of US3778148A publication Critical patent/US3778148A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • G03G21/06—Eliminating residual charges from a reusable imaging member
    • G03G21/08—Eliminating residual charges from a reusable imaging member using optical radiation
    • 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
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G03G15/045—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for charging or discharging distinct portions of the charge pattern on the recording material, e.g. for contrast enhancement or discharging non-image areas
    • G03G15/047—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material with means for charging or discharging distinct portions of the charge pattern on the recording material, e.g. for contrast enhancement or discharging non-image areas for discharging non-image areas
    • 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
    • G03G2215/0429—Changing or enhancing the image
    • G03G2215/0431—Producing a clean non-image area, i.e. avoiding show-around effects
    • G03G2215/0434—Parameters defining the non-image area to be cleaned
    • G03G2215/0443—Copy medium outline relative to the charge image
    • 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
    • G03G2215/0429—Changing or enhancing the image
    • G03G2215/0431—Producing a clean non-image area, i.e. avoiding show-around effects
    • G03G2215/0448—Charge-erasing means for the non-image area

Definitions

  • ABSTRACT In a copying machine characterized in that a charging device, an exposure device, a development device, a transferring device for transferring the developed image to a transfer medium such as paper, a cleaning device and a discharging device are provided around a photoconductive drum in the foregoing order, the improvement comprising means for introducing a discharging light disposed next to the charging device, and a shutter which intercepts the discharging light for a time corresponding to the length of the transfer medium only when the transfer medium enters the body of the copying machine.
  • This invention relates to a copying machine and method, more particularly to a copying machine which has a discharging device for extinguishing unnecessary part of a latent image before development of the latent image electrosta'tically formed in an electrostatic copying machine.
  • Exposure step b In this step, a light image is projected through an exposure device 3. onto the photoconductive drum 1 bearing the uniformly distributed charges which were deposited thereon by during previous charging step 0, thereby extinguishing charges at those portions where the light impinges to form a latent image according to the light image.
  • Development step c In this step, developer consisting of colored powder termined toner and particles termed carrier is flowed onto the latent image by means of a development device 4, thereby causing the toner to stick to the latent image and make it visible.
  • Transferring step d In this step, the toner image on the photoconductive drum 1 made during the development step c is transferred'toa transfer medium P such as a paper sheet by means of a transferring device or corotron 5 which includes means for charging the back surface of the transfer medium P to the same polarity as that of the charge formed during the charging step a.
  • a transfer medium P such as a paper sheet
  • Preliminary cleaning step e In this step, the attrative force of thetoner to the charge on the photoconductive drum 1 is weakenedto faclitate the drum cleaning of the nextstep.
  • a preliminary cleaning device 6 such as an A.C. or DC. corotron of the opposite polarity to that used in charging step a is employed.
  • Cleaning stepf lnthis step, thetoner remaining'on the photoconductive drum 1 is removed by means of a cleaning device 7'such as a brush which removes the toner and cleans the photoconductive drum surface, thus preparing the drum for the subsequent copycycle.
  • a cleaning device 7' such as a brush which removes the toner and cleans the photoconductive drum surface
  • Discharging step g In this step, electrostatic charges remaining on the photoconductive drum 1 are extinguished or eliminated by use of a discharging device 8 such as a lamp, and thus an electrically clean photoconductive drum surface is provided for the subsequent copy cycle.
  • a discharging device 8 such as a lamp
  • Ths invention has been made in view of the abovementioned problems and has an object to provide a copying machine which has means for developing latent images only when required for transfer.
  • this invention includes a discharging means such as a light source which continuously irradiates the drum.
  • This discharging step occurs after the charging step.
  • the discharging is interrupted with a shutter, for example, when the transfer medium enters the body of the copying machine, the length of the interruption corresponding to the detected length of the transferring medium whereby a latent image may be formed and developed as discussed hereinbefore.
  • FIG. 1 is a schematic view of a conventional copying machine.
  • FIG. 2 is an illustrative schematic view of a copying machine in accordance with the present invention.
  • FIGS. 3 and 4 are illustrative schematic, shutter operating circuits in acopying machine in accordance with thepresent invention.
  • a charging device 2 an exposure device 3, a developement device 4, transferring device 5, a preliminary cleaning device 6, a cleaning device 7 and a discharging device or lamp 8 are arranged around a photoconductive photosensitive drum 1 as in a conventional copying machine.
  • Some of the light 9 from a discharge lamp 8 is irradiated on the photosensitive drum 1 by way of a mirror 10 and an exposure slit ll of the exposure device 3.
  • the mirror 10 may be replaced by an additional discharge lamp (not shown).
  • This additional. discharge lamp would correspond to the light portion 9 and the additional discharge lamp will hereinafter be termed lamp 9. In this case, there would be no opening in the side of the enclosure for discharge lamp 8.
  • a shutter 12 for intercepting or releasing the light, the shutter 12 being operated by energization of a soleniod 13.
  • the light from discharge lamp 9 may be directed onto the drum 1 anywhere between the charging device 2 and the developing device 4 although, for purposes of illustration, the light is directed in the exposure slit ll of the exposure device 3 in FIG. 2. Therefore, there is no fear that toner will stick to the drum surface by the subsequent development device 4.
  • a paper sensing switch 14 may be provided in a passage (not shown) in the copying machine for the transfer medium.
  • the switch 14 may be connected with solenoid 13.
  • a transfer medium fed in the passage closes the paper sensing switch 14, and the solenoid 13 is energized thereby operating the shutter 12 and intercepting the light from the discharge lamp 9.
  • the solenoid 13 is deenergized and the shutter 12 is released so that the light from discharge lamp 9 is again radiated onto the photoconductive drum 1.
  • the shutter 12 intercepts the light of the discharge lamp 9 for a length of time at least as long as the time corresponding to the length of the transfer medium. Accordingly, a latent image may be formed by exposure device 3 during this time.
  • two paper sensing switches 14a and 14b are provided as shown in FIG. 4 with a proper distance therebetween equivalent to the length of the gripper.
  • the shutter operates to intercept the light of the discharging device only during the time corresponding to the length, only images having a length corresponding to the length of the transfer medium are formed and no image is formed when the transfer medium does not come into the body of the copying machine because of accidents such as jamming of papers. Therefore, the cleaning device is only required to remove a small amount of residual toner. Further, the quality of the copy is improved, the interior of the machine is kept clean and the consumption of the toner is decreased.
  • a copying machine comprising a charging device, an exposure device, a development device, a transferring device for transferring the developed image to a' transfer medium, a cleaningdevice and a discharging device disposed around a photoconductive drum in the foregoing order
  • the improvement comprising means for introducing a discharging light onto the photoconductive drum between the charging device and the development device, and shutter means for intercepting the discharging light for a length of time corresponding to the length of the transfer medium only after the transfer medium enters the body of the copying machine.
  • the length of said interruption being approximately the length of time required for said developed image to be transferred to said transfer medium during said transfer step whereby the latent image may be formed on said photoconductive member during said interruption so that said developer is placed on said photoconductive member only for a length of time approximately as long as the interruption
  • developer is not placed on said photoconductive member whenever it is not necessary to transfer developer to the transfer medium so that residual developer on said photoconductive member is substantially removed during said cleaning step to thereby clean the photoconductive member for the next cycle of copying.
  • the length of said interrupting step is effected by sensing the length of time it takes for said transfer medium to pass a first predetermined point after it has entered the body of said copying machine.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Cleaning In Electrography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Control Or Security For Electrophotography (AREA)
US00317779A 1971-12-27 1972-12-22 Apparatus and method for selectively discharging the photoconductive surface of an electrostatic drum copier to facilitate the cleaning thereof Expired - Lifetime US3778148A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10548371A JPS5618953B2 (de) 1971-12-27 1971-12-27

Publications (1)

Publication Number Publication Date
US3778148A true US3778148A (en) 1973-12-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00317779A Expired - Lifetime US3778148A (en) 1971-12-27 1972-12-22 Apparatus and method for selectively discharging the photoconductive surface of an electrostatic drum copier to facilitate the cleaning thereof

Country Status (5)

Country Link
US (1) US3778148A (de)
JP (1) JPS5618953B2 (de)
DE (1) DE2263707C3 (de)
FR (1) FR2354029A5 (de)
GB (1) GB1412249A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4047811A (en) * 1976-05-27 1977-09-13 Xerox Corporation Available light marginal illumination system
US4095890A (en) * 1975-06-24 1978-06-20 Oce-Van Der Grinten N.V. Xerographic copying apparatus
US4126388A (en) * 1976-03-15 1978-11-21 Minolta Camera Kabushiki Kaisha Electrophotocopying machine of electrostatic latent image transfer type
US4136942A (en) * 1975-11-25 1979-01-30 Canon Kabushiki Kaisha Electrophotographic apparatus
US4244647A (en) * 1978-04-07 1981-01-13 Minolta Camera Kabushiki Kaisha Erasing device for image transfer type copying apparatus
US4350750A (en) * 1976-01-23 1982-09-21 Ricoh Company, Ltd. Electrophotographic process
US4534641A (en) * 1983-10-31 1985-08-13 Xerox Corporation Charge erase device for copying or reproduction machines and printers
US4538900A (en) * 1983-11-09 1985-09-03 Ricoh Company, Ltd. Electrophotographic copying apparatus including drum conditioning apparatus and method
US4561761A (en) * 1984-06-25 1985-12-31 Xerox Corporation Charge erase device for copying or reproduction machines and printers
US4785324A (en) * 1986-03-26 1988-11-15 Kabushiki Kaisha Toshiba Electrophotographic apparatus and method for preventing the lowering of a charging voltage at a photoreceptor
US4963931A (en) * 1985-08-05 1990-10-16 Oce Nederland B.V. Regulating means for automatically adjusting a margining means in a copier to produce image-free image carrier zones in response to image positioning prior to image transfer
US5072260A (en) * 1987-05-26 1991-12-10 Canon Kabushiki Kaisha Image forming apparatus having analog and digital exposure means
US5459557A (en) * 1992-06-30 1995-10-17 Canon Kabushiki Kaisha Image forming apparatus
US20150023696A1 (en) * 2013-07-17 2015-01-22 Kyocera Document Solutions Inc. Image forming apparatus and light concentrating device

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2535366C3 (de) * 1974-08-14 1981-05-07 Ricoh Co., Ltd., Tokyo Elektrophotographisches Verfahren und Einrichtung
JPS51119229A (en) * 1975-04-11 1976-10-19 Minolta Camera Co Ltd Electrophotography
JPS5229145U (de) * 1975-08-21 1977-03-01
JPS599054B2 (ja) * 1975-10-29 1984-02-29 ミノルタ株式会社 電子複写装置
CH621421A5 (en) * 1976-03-31 1981-01-30 Du Pont Magnetographic dry copying process and device for carrying it out
JPS5550291A (en) * 1978-10-09 1980-04-11 Toshiba Corp Electronic copier
DE2929037A1 (de) * 1979-07-18 1981-02-05 Siemens Ag Verfahren und vorrichtung zur ionografischen roentgenbild-aufzeichnung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3318698A (en) * 1963-05-03 1967-05-09 Xerox Corp Xeroprinting reproduction
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage
US3698926A (en) * 1969-11-11 1972-10-17 Katsuragawa Denki Kk Method and apparatus for supplementing toner in electrophotographic machines

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2909971A (en) * 1954-03-29 1959-10-27 Ibm Printing machine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3318698A (en) * 1963-05-03 1967-05-09 Xerox Corp Xeroprinting reproduction
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage
US3698926A (en) * 1969-11-11 1972-10-17 Katsuragawa Denki Kk Method and apparatus for supplementing toner in electrophotographic machines

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4021111A (en) * 1974-06-10 1977-05-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
USRE30535E (en) * 1974-06-10 1981-03-03 Ricoh Co., Ltd. Developing device in electrophotographic copying apparatus
US4095890A (en) * 1975-06-24 1978-06-20 Oce-Van Der Grinten N.V. Xerographic copying apparatus
US4136942A (en) * 1975-11-25 1979-01-30 Canon Kabushiki Kaisha Electrophotographic apparatus
US4350750A (en) * 1976-01-23 1982-09-21 Ricoh Company, Ltd. Electrophotographic process
US4126388A (en) * 1976-03-15 1978-11-21 Minolta Camera Kabushiki Kaisha Electrophotocopying machine of electrostatic latent image transfer type
US4047811A (en) * 1976-05-27 1977-09-13 Xerox Corporation Available light marginal illumination system
US4244647A (en) * 1978-04-07 1981-01-13 Minolta Camera Kabushiki Kaisha Erasing device for image transfer type copying apparatus
US4534641A (en) * 1983-10-31 1985-08-13 Xerox Corporation Charge erase device for copying or reproduction machines and printers
US4538900A (en) * 1983-11-09 1985-09-03 Ricoh Company, Ltd. Electrophotographic copying apparatus including drum conditioning apparatus and method
US4561761A (en) * 1984-06-25 1985-12-31 Xerox Corporation Charge erase device for copying or reproduction machines and printers
US4963931A (en) * 1985-08-05 1990-10-16 Oce Nederland B.V. Regulating means for automatically adjusting a margining means in a copier to produce image-free image carrier zones in response to image positioning prior to image transfer
US4785324A (en) * 1986-03-26 1988-11-15 Kabushiki Kaisha Toshiba Electrophotographic apparatus and method for preventing the lowering of a charging voltage at a photoreceptor
US5072260A (en) * 1987-05-26 1991-12-10 Canon Kabushiki Kaisha Image forming apparatus having analog and digital exposure means
US5459557A (en) * 1992-06-30 1995-10-17 Canon Kabushiki Kaisha Image forming apparatus
US20150023696A1 (en) * 2013-07-17 2015-01-22 Kyocera Document Solutions Inc. Image forming apparatus and light concentrating device
US9304431B2 (en) * 2013-07-17 2016-04-05 Kyocera Document Solutions Inc. Image forming apparatus and light concentrating device

Also Published As

Publication number Publication date
JPS4871240A (de) 1973-09-27
JPS5618953B2 (de) 1981-05-02
GB1412249A (en) 1975-10-29
FR2354029A5 (fr) 1977-12-30
DE2263707C3 (de) 1978-12-21
DE2263707B2 (de) 1978-05-03
DE2263707A1 (de) 1973-07-05

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