US3724942A - Photoconductor discharge shutter assembly - Google Patents

Photoconductor discharge shutter assembly Download PDF

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Publication number
US3724942A
US3724942A US00243137A US3724942DA US3724942A US 3724942 A US3724942 A US 3724942A US 00243137 A US00243137 A US 00243137A US 3724942D A US3724942D A US 3724942DA US 3724942 A US3724942 A US 3724942A
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United States
Prior art keywords
illumination
document
photoconductor
shutter
light
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Expired - Lifetime
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US00243137A
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English (en)
Inventor
D Gibson
F Johnson
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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
    • G03G15/04—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
    • G03G2215/0436—Document properties at the scanning position, e.g. position and density
    • 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
    • G03G2215/0463—Exposure lamp used for scanning

Definitions

  • ABSTRACT A shutter arrangement is disclosed which at preselected intervals opens and closes to either permit light to illuminate a document plane or reflect light to the photoconductor of an electrostatic copying machine having the capability of half tone development, thus preventing the toning of unexposed areas of the photoconductor which bear no relation to the vdocument being copied.
  • the control arrangement opens the shutter during the normal scanning portion when a document is exposed to the illumination light and closes the shutter at a point corresponding approximately to the end of the document scan thus reflecting light to the photoconductor as if the photoconductor was receiving light from a white document, to discharge the unused portion of the photoconductor. This prevents excessive toning and the associated cleaning problems since this portion of the photoconductor will not have the toner transferred from it to a copy sheet.
  • the toner is strongly attracted to the latent electrostatic image formed on a photoconductive surface when it has been charged and then exposed imagewise to an original document.
  • the toning of the electrostatic image on the photoconductor is accomplished by the attraction of the toner particles to that portion of the latent image which remains charged to a high level after the exposure step.
  • the toning in a cascade developer unit is generally only effective in the edge portion of the large black area developed. This is due to the fact that the strongest attraction for the toner particle is in the fringes or'edge areas where the electrostatic field is strongly developed and concentrated between charged andv adjacent uncharged areas. In the center portion of a large charged area the electrostatic field is not strongly developed or concentrated in such a configuration that the toner particles are strongly attracted and thus the phenomenon known as washout occurs leaving only a development pattern known as edge development for large black areas.
  • the toner which is removed from the photoconductor in the large, heavily toned areas rapidly overloads the cleaning system and more specifically fills and overloads the vacuum bag of the cleaning system. This is a waste of toner and there is no beneficial effect derived from this toner.
  • photoconductors are wider than the copy being made to ensure that all portions of the image focused on the photoconductor are received on a portion of photoconductive material which may respond to that image.
  • portions of the photoconductor which are not exposed to the image or which lie on either side of the document image.
  • This portion of the photoconductor if not otherwise treated would be toned or developed and sent through the remaining process steps of the xerographic process. Since no copy sheet would be presented to that portion of the photoconductor, the toner particles attracted to and held on this highly charged portion of the photoconductive member will not be transferred and must be removed by the cleaning station of the electrostatic copying apparatus.
  • edge erase lamps where light is impinged from a lamp or light source through a control shielding arrangement onto the edge portions of the photoconductor which lie outside the image of the document being copied. This discharge usually occurrs after the exposure and prior to the developing of the latent electrostatic image.
  • the discharge lamps effectively expose these edge areas the photoconductor becomes conductive and the charge level on those portions of the photoconductive surface drop to a residual voltage level which is generally insufficient to atnact and retain significant quantities of toner particles.
  • the erase lamp technique is additionally used where a lamp is energized and caused to illuminate portions of the photoconductive surface between images when the electrostatic copying machine is conditioned for a smaller size copy thus leaving an unused portion of the photoconductor between images. This technique requires precise control of the period that the lamp is on.
  • a difierent type solution has been applied to those machines which use a flash illumination for illuminating the original document during the exposure step.
  • flash illumination systems it is possible to conduct light through a light conductor such as fiber-optical members and other similar type light conducting mechanisms and impinge this light onto the photoconductor at point where it is desired that the electrostatic charge be dissipated to prevent the toning of the charged but yet unused portions of the photoconductor, such as inter-image gaps.
  • This technique is not readily applicable in an environment which uses a scanning illumination exposure apparatus.
  • a shutter or other light reflective means is positioned'in the light path from the illumination bulbs to reflect light in the same manner that a document would reflect light if that document were on the document plane.
  • This light reflective surface or shutter is actuated to move into an intercepting position at a point which corresponds to the end of the scan of either an I l. or. 14 inch document or for other sizes when the apparatus is] adjusted or modified for non-standard'paper lengths.
  • the shutter closes and thus presents a white reflective surface to the light rays emanating from the illumination package or illumination assembly and effectively appears to the photoconductor the same as a white sheet of paper would appear if a white sheet occupied the document plane at that point.
  • the shutter arrangement remains closed thus discharging all portions of the photoconductor which pass the exposure station during the period of rescan and thereby prevent it from being toned in that region.
  • the shutter Upon completion of the re-scan motion the shutter is opened at a point prior to the edge of the document so that as the illumination assembly begins its scanning motion the light from illumination source is impinged upon the original document and the reflected light from the document carrying the image of that document is being focused on the photoconductor surface to expose the photoconductor and thus fonn a latent electrostatic image which may be subsequently processed.
  • the illumination assembly teaches that point which corresponds to the end of scan for the size document selected, the shutter is closedand the scanning cycle is continued to the end of scanning movement.
  • an electrophotographic photoconductive member or photoconductor I0 is pro vided.
  • the photoconductor 10 is preferably formed in 5 the shape of a revolving drum.
  • a drive means or cable 12 is driven in synchronism with the rotation of the drum. This may be accomplished by any conventional means such that a desired length of cable 12 is driven past any preselected point in relation to a pre-determined peripheral length of the photoconductor 10.
  • reflector 18 The positioning of reflector 18 around lamp 16 is such that the light which reaches document plane 22 is focused to a relatively narrow footprint of light or band of light which illuminates the entire width of the document and a incremental length of the document.
  • Reflector l8, lamp 16, and mirror are all fixedly attached to carriage 14 such that the translational movement of carriage 14 in response to the timed rotation of photoconductive drum 10, causes a scanning of document plane 22.
  • the position of reflector 18', lamp l6, and mirror 20' illustrate a position which these elements will occupy part way through a completed scanning movement.
  • a mirror 26 is mounted below the point at which the footprint of light from mirror 20 illuminates document plane 22.
  • Mirror 26 is positioned to direct the light to other reflecting surfaces in the optical path. These other reflecting surfaces are mirrors 28, 30, and 32.
  • Mirrors 28 and 30 are fixedly attached to a translatable carriage. As carriage '14 is translated in response to the movement of cable l2, mirrors 28 and 30 likewise scan due to the movement of the carriage to which they are attached.
  • velocity of the mirrors 28 and 30 in a horizontal direction is one half of the'velocity of carriage 14, in order to provide a constant length optical path from any point on document plane 22 through mirrors 26,
  • FIG. 1 illustrates the entire illumination assembly which is in turn mounted on carriage 14.
  • the parabolic reflector 18 has mounted within it a light source 16 such that the light reflected from the reflector 18 partially focuses on mirror 20 and illuminates a footprint of light on the document plane 22.
  • the light rays emanating from lamp 16 and reflected from mirror 20 are intercepted by the shutter 42 in as much as shutter 42 is closed.
  • shutter 42 which is generally a white or light colored finish
  • the image transmitted through the remainder of the optical system does not have any history of the document or any objecton the document plane 22.
  • the effect will be to expose the photoconductive surface of drum 10 with a light which is uniforrnally transmitted and thus present to the photoconductive surface 10 the same type of exposure as would be encountered with light which is reflected from atotally white blank document.
  • the light rays reflected from shutter 42 in its closed position then cause discharge of any electrostatic charge placed on the photoconductive surface by charging corona 34 as shown in FIG. 4.
  • FIG. 2 also illustrates the shutter in its open position or copying position at 42'.
  • the movement of shutter 42 from its closed position to its open position 42 is effected through the use of a bail 44 which in turn causes arm 46 to rotate about the pivot point defined by bail 44.
  • the rotation of bail 46 is controlled by a knockoff cam lever 48 as illustrated in FIG. 1.
  • Knockoff cam lever 48 has a camming surface 50 designed to engage a cooperating engaging member 52, or knockoff stop 52, if the length of scan desired is less than the complete scan capability of the overall reproduction apparatus, or alternatively cam stop 54 to close the shutter at the end of the longest permissible scan.
  • a limit stop 56 or shutter opening means 56 is provided.
  • Actuator arm 48 engages limit stop 56 at the point that is just prior to the carriage 14, reflector 18, mirror 20, and shutter 42 reaching the end of a re-scan movement prior to the initiation of the scanning movement.
  • Limit stop 56 in engaging control arm 48 or lever 48, causes control arm. 48 to rotate in a clockwise direction as viewed in FIG. 3, through a small segment of a circular movement around bail 44. This moves arm 46 in a clockwise movement retracting shutter 42 to position 42. In this position the illumination assembly is ready for scanning and the light rays emanating from lamp source 16 and impinging on mirror 20 are focused into a footprint of light on the document plane 22.
  • Either cooperative engaging member 52 or 54 acts to close the shutter '42 at the desired point of the subsequent scan.- To allow the shutter 42 to either close at the end of a normal 11 inch document scan or to remain open for an extended scan of 14 inches or such other length as the basic scanning mechanism is capableof performing, engaging member 52 is pivotally mounted at 58 to allow it to pivot out of the path of control arm 48 and camming surface 50. This control is accomplished through a boden cable 60 or other equivalent mechanism interconnecting engaging member 52 with the copy size selection control 62.
  • Copy selection control 62 may be comprised of a pivotally mounted toggle lever 64 as shown in FIG. 2 or other motion translating mechanism which moves in response to the depression of control buttons or other control members which are actuated in response to a.
  • Button 66 would be depressed to secure a 14 inch copy while button 68 would be depressed tosecure an ll inch copy.
  • This copy size control mechanism is further connected into the paper transport system to ensure that the right size sheet is fed or the proper length of sheet is severed from a roll feed. i
  • the illumination assembly is then prepared for the re-scan portion of the optical system movement.
  • a document to be copied for example a standard letter size document, is placed on the document plane 22 with one edge positioned against edge guide 24.
  • the machine operation is initiated through any conven tional operator control to begin the copying operation.
  • the drum carrying the photoconductive surface 10 begins its clockwise rotation and carriage 14 is moved toward the left as viewed in FIG. 4.
  • engaging pin 54 insured that control arm 48 was rocked in a counterclockwise position insuring that shutter 42 was closed.
  • the lamp 16 is illuminated during the re-scan portion of the cyclic operation and light is reflected from reflector 18 and mirror 20 onto the underside of shutter 42.
  • the light rays impinging on the underside of shutter 42 reflect from the shutter onto mirror 26, mirror 28, mirror 30, and mirror 32 and are focused at the exposing point 33 v on photoconductive drum 10.
  • the photoconductive surface of drum 10 in what may be characterized as an unused portion of the drum, is illuminated and thus discharged from its dark charge level deposited by charging corona 34.
  • Carriage 14 then is driven in optically synchronized movement with the surface of drum 10, to scan the document previously placed on the document plane 22.
  • the image of the document is transmitted through the same optical path described above and presented to the I surface of photoconductive drum 10 where the light reflected from the original exposes the charged photoconductive surface 10 and allows the photoconductor to become conductive and dissipate the electrostatic charge in the areas corresponding to light areas of the original. Dark areas of the originaldo not reflect light and the lack of light impinging on the photoconductor does not allow the reduction of the charge level and thus the areas corresponding to black or dark porthe illumination assembly moving with it, causes the,
  • Engageable member 52 has been positioned into the path of movement of cam surface 50 by the depression of the copy size selector apparatus, specifically button 68 which acts through toggle link 64 and boden cable to cause member 52 to pivot around pivot point 58 into the path of cam surface 50.
  • the control arm 48 isrocked in a counterclockwise direction and as discussed earlier closes shutter 42 through the action of arms 46.
  • the rotation of control arm 48 in a counterclockwisedirection lowers cam sur' face 50 down below engageable member 52 such that on a re-scan motion there will be clearance between the upper portion of control arm 48 and engageable member 52.
  • the illumination assembly continues its movement in the scanning direction the light which is produced by lamp 16 is reflected from the parabolic reflector 18 and partially focused on mirror 20 and then projected onto the underside of shutter 42.
  • the light illuminating the underside of shutter 42 is reflected by the light colored highly reflective surface through the normal optical path and discharges the photoconductor during this portion of the cycle which when correlated to the photoconductive surface 10 corresponds to an unused photoconductor segment.
  • Engageable member 54 is positioned to close the shutter in the same fashion as engageable member 52 closes the shutter. However, it is positioned to effect the closing at a point corresponding to the trailing edge of a 14 inch document.
  • the photoconductor 10 is then presented to a development station 36.
  • developer station is a magnetic brushdeveloper assembly 36.
  • the magnetic brush developer as-' sembly may be replaced with a development electrode developer station if desired.
  • the carrier particles which are formed into the bristles of a brush by magnets within the magnetic brush housing 36, rub against the surface of the photoconductor 10 and deposit onto it small electroscopic particles of toner.
  • the toner is attached and adhered to that portion of the photoconductor retaining a high electrostatic charge. These portions correspond'to the dark portions of the original document.
  • the photoconduc tive surface 10 carries the toner particles past the transfer corona 38.
  • the transfer corona 38 is separated from the photoconductive surface 10 by a sheet or web of paper normally to receive the toner particles.
  • the transfer corona 39 counteracts the tendency of the toner particles to adhered to the photoconductor 10 and causes them to adhere to the support sheet for subsequent fusing of the copy.
  • the photoconductor l is then next presented to a cleaning station 40.
  • the photoconductor is cleaned by a rapidly revolving brush of either natural or synthetic fibers or bristles, and the undesirable toner residue which inherently remains on the photoconductive surface is brushed from that surface and trapped into a vacuum cleaning system. Alternate techniques of cleaning such as web cleaning and wiper cleaning are known in the art and would be acceptable alternatives to the vacuum-brush arrangement.
  • the photoconductor 10 is re-charged by charge corona 34 for subsequent exposure.
  • One characteristic of magnetic brush and developer electrode development stations is that large dark areas on the original which are manifested as large areas of high charge level on the photoconductive surface 10 are developed to substantially uniform darkness by the The scan portion of the operation is identical to developing station. As the images on a photoconductive drum surface 10 are, of necessity, separated from each other by some increment of distance there are portions of the photoconductor which can best be characterized as unused.
  • Cleaning stations for electrophotographic apparatuses are generally designed to satisfactorily clean small quantifies of toner and residue from the photoconductor after most if not substantially all of the toner has been transferred to the copy sheet.
  • the cleaning stations such as 40 are usually not capable of extensive cleaning of large quantities of residue toner. Even in the event that the cleaning station 40 is capable of this, the large quantity of toner which would be removed from the drum would represent a large waste of toner materials and further the depositing of this toner into a filtering bag or filtering arrangement would very quickly fill and clog the filter thus reducing its efficiency and further degrading operation of the electrophotographic copying apparatus.
  • the photoconductor By providing a selectively operable and timed apparatus for reflecting light onto the photoconductor 10 in those portions of the cycle which do not represent an image to'be copied, the photoconductor is discharged prior to developing and prevents the excessive toning of these unused portions of the photoconductor and reduces the cleaning requirements placed upon the cleaning station 40.
  • the high intensity of the illumination lamp 16 when concentrated in a small range of area as described above can be annoying to an operator. This would occur during any unused portion of the scan and during re-scan when the operator would be manually substituting a second document for a first document.
  • the undesirable exposure to the illumination source during unused portions of the scan and during the entire re-scan are substantially reduced if not completely eliminated.
  • a selectively operable shutter arrangement for intercepting light prior to it being impinged upon a document plane, in relation to the scanning and rescanning motion of an illumination assembly in an electrophotographic copier apparatus reduces the waste of toner and electroscopic developing materials, reduces operator annoyance by reducing or eliminating operatorexposure to high intensity light and improves the cleaning by a cleaning station thus maintaining or improving copy quality in electrophotographic apparatuses embodying development electrode and mag netic brush developer systems.
  • an illumination source means for directing illumination from said source onto a document plane; means for directing light reflected from said document plane to said photoconductive member and presenting an image of said document plane on the surface of said member; selectively operable means'for intercepting said illumination prior to said illumination being impinged onto said document plane and redirecting said intercepted illumination to present that illumination to the surface of said photoconductive member to expose and discharge said member.
  • a shutter arrangement may be implemented which compensates for the, difference in document lengths where the scandirection is across the width of the document.
  • a continuously adjustable scan control to with respect to said document plane.
  • said selectively operable means further comprises an adjustable engaging means and a cooperating control means, said adjustable engaging means being positioned in the path of said control means. and fixed with respect to said document plane to cause said selectively operable means to intercept said illumination during any time period after said engaging and control means contact each' other during an exposure cycle.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Systems Of Projection Type Copiers (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Control Of Exposure In Printing And Copying (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)
  • Projection-Type Copiers In General (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
US00243137A 1972-04-12 1972-04-12 Photoconductor discharge shutter assembly Expired - Lifetime US3724942A (en)

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US24313772A 1972-04-12 1972-04-12

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US (1) US3724942A (enrdf_load_stackoverflow)
JP (1) JPS5231741B2 (enrdf_load_stackoverflow)
CA (1) CA985733A (enrdf_load_stackoverflow)
FR (1) FR2179732B1 (enrdf_load_stackoverflow)
GB (1) GB1374564A (enrdf_load_stackoverflow)
IT (1) IT978354B (enrdf_load_stackoverflow)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3967896A (en) * 1975-05-14 1976-07-06 Rank Xerox Ltd. Variable edge fadeout apparatus for electrostatic reproduction machines
US3982116A (en) * 1974-08-06 1976-09-21 Ricoh Co., Ltd. Slit illumination system for copying machine
US3998541A (en) * 1975-04-18 1976-12-21 Eastman Kodak Company Illumination arrangement providing for interframe flashdown
US4008954A (en) * 1974-07-15 1977-02-22 Minolta Camera Kabushiki Kaisha Device for extinguishing unnecessary electrostatic charge in electrophotographic copier
US4023896A (en) * 1975-08-07 1977-05-17 Addressograph Multigraph Corporation Clean margin mechanism for electrostatic copiers
US4080071A (en) * 1975-09-09 1978-03-21 Rank Xerox Ltd. Exposure device of a copying machine
US4086008A (en) * 1976-11-04 1978-04-25 Oce-Van Der Grinten, N.V. Electrophotographic copying apparatus with device for exposing imaged photoconductive plate
US4095895A (en) * 1975-09-01 1978-06-20 Oce-Van Der Grinten N.V. Method and means for preventing edge shadow effects during episcopic exposure of an original
US4113373A (en) * 1975-06-28 1978-09-12 Agfa-Gevaert Ag Copying apparatus
US4133609A (en) * 1974-05-15 1979-01-09 Minolta Camera Kabushiki Kaisha Charge-erasing device for electrophotographic copying apparatus
US4148581A (en) * 1976-08-30 1979-04-10 Olympus Optical Company Limited Shutter opening and closing mechanism for an electrographic apparatus
US4166692A (en) * 1976-09-14 1979-09-04 Minolta Camera Kabushiki Kaisha Protection and safety device for a photocopying machine
US4173406A (en) * 1977-04-22 1979-11-06 Minolta Camera Kabushiki Kaisha Electrical charge removing arrangement for removing charge from non-image bearing portions of photo-sensitive medium
US4178095A (en) * 1978-04-10 1979-12-11 International Business Machines Corporation Abnormally low reflectance photoconductor sensing system
US4179213A (en) * 1978-04-10 1979-12-18 International Business Machines Corporation Vector pinning in an electrophotographic machine
US4183657A (en) * 1978-04-10 1980-01-15 International Business Machines Corporation Dynamic reference for an image quality control system
DE3026952A1 (de) * 1979-07-16 1981-02-05 Canon Kk Bilderzeugungsgeraet
US4505575A (en) * 1983-08-26 1985-03-19 Xerox Corporation Non-image erase system for reproduction machines
US4708455A (en) * 1982-09-30 1987-11-24 Canon Kabushiki Kaisha Image forming apparatus and a process unit for use in the same
US5365323A (en) * 1991-09-19 1994-11-15 Canon Kabushiki Kaisha Image recording device

Families Citing this family (3)

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Publication number Priority date Publication date Assignee Title
JPS5526520U (enrdf_load_stackoverflow) * 1978-08-07 1980-02-20
JPS55135867A (en) * 1979-04-10 1980-10-23 Ricoh Co Ltd Optical device of copying machine
JPS566270A (en) * 1979-06-28 1981-01-22 Sharp Corp Electrophotographic apparatus

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US3375806A (en) * 1965-05-06 1968-04-02 Xerox Corp Xerographic donor development apparatus
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage
US3556655A (en) * 1968-01-22 1971-01-19 Addressograph Multigraph Photoelectrostatic copying machine
US3671121A (en) * 1970-08-05 1972-06-20 Eastman Kodak Co Exposure device for controlling charge on a portion of a charged surface bordering an image frame projected on the charged surface

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US3375806A (en) * 1965-05-06 1968-04-02 Xerox Corp Xerographic donor development apparatus
US3556655A (en) * 1968-01-22 1971-01-19 Addressograph Multigraph Photoelectrostatic copying machine
US3540806A (en) * 1968-03-06 1970-11-17 Xerox Corp Half-toning method and apparatus for solid area coverage
US3671121A (en) * 1970-08-05 1972-06-20 Eastman Kodak Co Exposure device for controlling charge on a portion of a charged surface bordering an image frame projected on the charged surface

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4133609A (en) * 1974-05-15 1979-01-09 Minolta Camera Kabushiki Kaisha Charge-erasing device for electrophotographic copying apparatus
US4008954A (en) * 1974-07-15 1977-02-22 Minolta Camera Kabushiki Kaisha Device for extinguishing unnecessary electrostatic charge in electrophotographic copier
US3982116A (en) * 1974-08-06 1976-09-21 Ricoh Co., Ltd. Slit illumination system for copying machine
US3998541A (en) * 1975-04-18 1976-12-21 Eastman Kodak Company Illumination arrangement providing for interframe flashdown
US3967896A (en) * 1975-05-14 1976-07-06 Rank Xerox Ltd. Variable edge fadeout apparatus for electrostatic reproduction machines
US4113373A (en) * 1975-06-28 1978-09-12 Agfa-Gevaert Ag Copying apparatus
US4023896A (en) * 1975-08-07 1977-05-17 Addressograph Multigraph Corporation Clean margin mechanism for electrostatic copiers
US4095895A (en) * 1975-09-01 1978-06-20 Oce-Van Der Grinten N.V. Method and means for preventing edge shadow effects during episcopic exposure of an original
US4080071A (en) * 1975-09-09 1978-03-21 Rank Xerox Ltd. Exposure device of a copying machine
US4148581A (en) * 1976-08-30 1979-04-10 Olympus Optical Company Limited Shutter opening and closing mechanism for an electrographic apparatus
US4166692A (en) * 1976-09-14 1979-09-04 Minolta Camera Kabushiki Kaisha Protection and safety device for a photocopying machine
US4086008A (en) * 1976-11-04 1978-04-25 Oce-Van Der Grinten, N.V. Electrophotographic copying apparatus with device for exposing imaged photoconductive plate
US4173406A (en) * 1977-04-22 1979-11-06 Minolta Camera Kabushiki Kaisha Electrical charge removing arrangement for removing charge from non-image bearing portions of photo-sensitive medium
US4178095A (en) * 1978-04-10 1979-12-11 International Business Machines Corporation Abnormally low reflectance photoconductor sensing system
US4179213A (en) * 1978-04-10 1979-12-18 International Business Machines Corporation Vector pinning in an electrophotographic machine
US4183657A (en) * 1978-04-10 1980-01-15 International Business Machines Corporation Dynamic reference for an image quality control system
DE3026952A1 (de) * 1979-07-16 1981-02-05 Canon Kk Bilderzeugungsgeraet
US4477179A (en) * 1979-07-16 1984-10-16 Canon Kabushiki Kaisha Image forming apparatus with adjustable light source
US4708455A (en) * 1982-09-30 1987-11-24 Canon Kabushiki Kaisha Image forming apparatus and a process unit for use in the same
US4505575A (en) * 1983-08-26 1985-03-19 Xerox Corporation Non-image erase system for reproduction machines
US5365323A (en) * 1991-09-19 1994-11-15 Canon Kabushiki Kaisha Image recording device

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Publication number Publication date
DE2315763B2 (de) 1976-10-28
DE2315763A1 (de) 1973-10-25
JPS5231741B2 (enrdf_load_stackoverflow) 1977-08-17
GB1374564A (en) 1974-11-20
IT978354B (it) 1974-09-20
FR2179732A1 (enrdf_load_stackoverflow) 1973-11-23
JPS4911139A (enrdf_load_stackoverflow) 1974-01-31
FR2179732B1 (enrdf_load_stackoverflow) 1976-10-08
CA985733A (en) 1976-03-16

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