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US3834807A - Copier with leading edge image control - Google Patents

Copier with leading edge image control Download PDF

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Publication number
US3834807A
US3834807A US00442533A US44253374A US3834807A US 3834807 A US3834807 A US 3834807A US 00442533 A US00442533 A US 00442533A US 44253374 A US44253374 A US 44253374A US 3834807 A US3834807 A US 3834807A
Authority
US
United States
Prior art keywords
image
copy
light
exposure window
leading edge
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
US00442533A
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English (en)
Inventor
S Fuller
H Munzel
C Queener
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.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to US00442533A priority Critical patent/US3834807A/en
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Publication of US3834807A publication Critical patent/US3834807A/en
Application granted granted Critical
Priority to IT30511/74A priority patent/IT1027651B/it
Priority to FR7443565A priority patent/FR2261558B1/fr
Priority to CA217,166A priority patent/CA1035004A/en
Priority to BE152342A priority patent/BE824343A/xx
Priority to JP50006010A priority patent/JPS5925219B2/ja
Priority to NL7500896A priority patent/NL7500896A/xx
Priority to GB383875A priority patent/GB1447819A/en
Priority to IL46565A priority patent/IL46565A/en
Priority to DK50575AA priority patent/DK142634B/da
Priority to DE2505833A priority patent/DE2505833C2/de
Priority to CH176975A priority patent/CH581852A5/xx
Priority to SE7501420A priority patent/SE391591B/xx
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
    • 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
    • G03G2215/0439—Automatic detection of properties
    • 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
    • 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
    • G03G2215/0468—Image area information changed (default is the charge image)
    • G03G2215/047—Image corrections
    • G03G2215/0473—Image corrections due to document imperfections, e.g. punchholes, books
    • 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
    • G03G2215/0468—Image area information changed (default is the charge image)
    • G03G2215/048—Technical-purpose-oriented image area changes
    • G03G2215/0482—Toner-free areas produced
    • G03G2215/0485—Avoiding problems in standard processing steps, such as transfer and fixing
    • 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
    • G03G2215/0468—Image area information changed (default is the charge image)
    • G03G2215/0492—Without changing the charge image

Definitions

  • No.: 442,533 controlled by means detecting a low average intensity of reflected light during initial stages of scan of an original being copied to produce a low density or light [52 US. Cl. 355/3 R, 355/8, 1 gag/.751, copy adjacent the leading edge Ofthe copy Sheet paw 51] I t Cl G03 15/00 ing through the machine thereby minimizing paper [58] g llg7/l7 5. feed difficulties associated with the passage of copy having a dense leading edge through a contact fuser.
  • inter-image erase circuitry activates an erase lamp at the beginning of a copy cycle to prevent development of a photoconductor in fixed regions outside the pre-set image area.
  • control circuitry compares the sensed average light intensity with a pre-set threshold value. When the reflected light sensed exceeds the threshold, the erase lamp is extinguished and the copy process proceeds normally. The copy produced will have an unobjectionable white edge which readily passes through the contact fuser. Additionally, toner usage and cleaning requirements are reduced.
  • Our invention can be implemented by a variety of techniques that vary from the preferred embodiment as described generally above.
  • the image on the leading edge need not be entirely erased to obtain the benefits of our invention.
  • a low density image can be produced in the region of the leading edge which would preserve any information that might be found in an original having a dense image in the vicinity of the leading edge.
  • the leading edge image can also be lightened or eliminated by control of the transfer station or, if timing considerations permit, control of the sensitizing charge corona. While we prefer to sense average light intensity by a photodetecting device mounted on a member that remains positionally associated with the scan footprint of reflected light such as a scanning lens, other arrangements for average light determination can be employed.
  • copy machines ordinarily are provided with a document cover having a light background that normally obviates the problem to which our invention is directed.
  • the document cover For copy machines capable of making copies from thick documents such as books, provision is made for the document cover to be raised to accommodate the book thickness.
  • FIG. 1 shows in simplified form, a xerographic type copy machine or printer employing leading edge density control in accordance with our invention
  • FIG. 2 is a logic diagram of the control for our invention
  • FIG. 3 is a perspective exploded view of a light sensing device employed in our invention.
  • FIG. 4 is a circuit diagram of an approriate threshold detecting circuit employed in the control logic of FIG. 2.
  • FIG. 1 there is shown a xerographic type copy machine or printer 10 including a rotatable drum or image production member 11 having a photoconductive peripheral surface 12 that is movable along a copy production path past electrostatic imaging operation performed by a sensitizing charge corona 13, an image exposing station 14; a magnetic brush developing station 40 at which a toner powder image 15 is developed on surface 12, and a transfer corona station 16 at which the powder image 15 is transferred to a copy sheet 17.
  • a cleaning station 18 removes any residual toner particles from. the photoconductive surface 12 prior to the surface being represented to the sensitizing charge corona 13.
  • optical scanning apparatus 20 within a light tight housing 30 causes a flowing segmental light image reflected from a document 19 supported on exposure window 31 to be presented to the photoconductive surface 12 in synchronism with its movement along path 12a.
  • This flowing image is created by the movement of an optical element such as a lens 21 along a scanning path 21a that is parallel to one axis of the exposure window 31.
  • Lens 21 is mounted on a scan producing carriage 22 which in turn is supported by suitable rails or tracks 23.
  • Carriage 22 is driven at an appropriate speed to provide the flow image synchonous with drum 11 through a transmission 24.
  • a flexible diaphragm or curtain member 32 surrounds the lens 21 and assures that only light passing through lens 21 can reach photoconductive surface 12.
  • a pair of normally stationary mirrors 33 and 34 re-direct the light received from lens 21 to the photoconductive surface 12.
  • Magnetic brush developing station 40 presents electroscopic toner powder to a latent electrostatic charge image created by exposing station 14.
  • Developing station 40 includes a magnetic brush unit 42 having an electrically biased conductive cylinder 44 which performs the functions of a development electrode and thus is capable of faithfully reproducing half-tone and broad area solid black images as well as line images.
  • the powder image generated by developing station 40 is transferred to the copy sheets 17 which are presented in synchronism with the movement and position of photoconductive surface 12.
  • Copy sheets 17 are transported from the transfer station 16 by a pneumatic conveyor 50 through an image fixing contact fuser 51 where the powder image is permanently bonded to the copy sheet 17.
  • Exit feed rolls 52 deliver the finished copy sheet to an exit pocket 53 for removal.
  • Contact fuser 51 can be like that described in U.S. Pat. application Ser. No. 317,482 of James A. Machmer entitled HIGH SPEED PRINTING SYSTEM WITH HEATED ROLL FUSER (LE9-72-0l9).
  • the fuser consists of a heated fusing roll 54 having an internal heat source and a heated surface 55 formed of a deformable silicone elastomer having an inherent low adhesive quality with respect to the thermoplastic toner material of powder image 15.
  • the fuser 51 further comprises an unheated backup or pressure roll 56 which brings the copy sheet 17 and the powder image thereon into intimate contact with the heated surface 55.
  • A'document hold down cover 37 is pivotally mounted adjacent exposure window 31 and carries a white background surface member 38 which can be placed overa thin document positioned on exposure window 31 to cover regions such as 29.
  • the uncovered margin portion 29 of the exposure window 31 will occur most commonly when undersized documents such as the page of a small book are being copied and the thickness of the document prevents closing of cover 37.
  • an elongated discharge or erase lamp 60 is positioned between exposing station 14 and developing station 40. This discharge lamp 60 normally serves to provide the known function of erasing or discharging the photoconductor 12 in the region following the trailing edge of a first copy and preceeding the leading edge of the image area for a successive copy.
  • control of discharge lamp 60 can be conveniently provided by a drum position sensing device such as cam 61 and associated switches 62 and 63.
  • Cam 61 is configured toclose switch 62 at the time that the leading edge of the image area on photoconductive surface 12 arrives in alignment with discharge lamp 60.
  • Switch 63 is closed at the time'that the trailing edge of the image area on photoconductive surface 12 passes the discharge lamp 60.
  • a latching switch 64 responds to closure of switch 63 to make discharge lamp 60 operative.
  • switch 65 hereinafter described, senses that cover 37 is down by being positioned in its broken line position
  • latching switch 64 responds to closure of image area leading edge indicative switch 62 to extinguish discharge lamp 60, making it unoperative.
  • Our invention controls the density of the leading edge of copy produced at transfer station 16 by providing an alternate contol for turning off lamp 60.
  • our alternate control is selected by cover down sensing switch 65 being positioned in its full line position in FIG. 2 as an indication that document cover 37 is in an open position.
  • Our control employs a reflected light intensity sensing device 70 including a circuit 80 for detecting the rise of reflected light intensity above a preset threshold for initiating a signal to reset latching switch 64 and make discharge lamp 60 unoperative after a time measured by a delay device or circuit 66 that is a measure of the time required for a point on photoconductive surface 12 at exposure station 14 to move into alignment with discharge lamp 60.
  • lamp 60 will remain ON beyond the leading edge of the image area on photoconductive surface 12 normally defined by the closure of switch 62.
  • Light intensity sensing device 70 will sense a low level of light so long as mirror 26 projects light through window 31 in regions where the light is not reflected back by a document 19 thereon. As the scanning band of light from mirror 26 reaches the left or leading edge of document 19, the light intensity received by sensing device 70 will rise rapidly and a signal will be initiated to delay circuit 66.
  • Lamp 60 will remain ON to discharge photoconductive surface 12 until the delay period has expired, at which time the electrostatic image of the left edge of document 19 will reach the location of discharge lamp 60. Completion of the delay time will transmit the turnoff signal to latching switch 64 which will extinguish the lamp 60 and allow the copy process to proceed in a normal manner. Since the leading edge of the'image area on photoconductive surface 12 has been discharged by lamp 60, no toner material will be developed onto the photoconductive surface 12 by developing station 40 and no image will be transferred to the leading edge of copy sheet 17 at transfer station 16. The untoned leading edge of the copy will pass readily through the contact fuser 51.
  • switch 65 it is possible to copy the full area of thin documents that may include dark portions adjacent the leading'edge scan region of exposure window 31.
  • the light intensity sensing device 70 is better shown in FIG. 3.
  • This device comprises a photo transistor 90 that is mounted under a light collecting condensing lens 71 on a printed circuit board 72 within a housing 73.
  • the housing 73 includes baffle walls 74 and 75 that limit the access of light to within the housing 73 to prevent direct impingement of light from lamp 35 (FIG. 1) onto phototransistor 90.
  • Tapered baffel walls 75 limit the lateral extent of the field of view of phototransistor 90. The field of view should be large enough to obtain a usefully representative sample of the light reflected from the exposure window 31 to distinguish between the presence and absence of a document thereon.
  • an opening 76 is provided in right side wall 77 of the housing 73 to enable phototransistor 90 to receive reflected light throughout the entire scan movement of lens 21 and mirror 26.
  • the condensing lens 71 is mounted directly above the phototransistor 90 to assist in collecting light from a broad area of the exposure window 5.7.
  • the collected light from a broad area thus represents an average intensity of the narrow illumination footprint 25 which is particularly suited for distinguishing between the presence and absence of a document on exposure window 57.
  • an incandescent lamp such as 35 generates a substantial amount of infrared light along with its visible light.
  • a dichroic cold mirror 36 that reflects only the visible light onto exposure window 31 thereby minimizing the tendency to heat the document 1.9 on the exposure window 31.
  • the infrared light simply passes through the dichroic mirror 36 and is reflected around within the optical system housing 30.
  • the inner walls 39 of housing 30 are colored with a flat black material to minimize internal reflections, however, the large amount of infrared produced by lamp 35 is not completely absorbed.
  • a blue-tint filter 78 that is superimposed over lens 71 and thus prevents transmission of infrared light to the phototransistor 90.
  • the threshold detecting circuit 80 carried by printed circuit board 72 within the housing 73 is shown in FIG. 4.
  • the detecting circuit 80 is provided with a positive power supply input 81, a negative power supply input 82, and a ground input 83.
  • the input positive power is smoothed by resistor 84 and capacitor 85 and is applied to similar circuit branches 91 and 92 to derive comparative voltages on lines 93 and 94 that are input to an operational amplifier 86 connected by resistor 87 as a Schmitt trigger to generate a precise fast output on line 88.
  • a circuit branch 91 includes phototransistor 90 whose operating status is altered in proportion to the intensity of light applied thereto, voltage dividing resistors 91a and 91b, base resistor and load resistor 96.
  • Resistor 91b includes a variable potentiometer tap 97 by which the threshold to which the circuit 80 responds can be adjusted.
  • a voltage level thus is derived on line 93 that is a function of the light level intensity applied to phototransistor 90 and a particular setting of threshold adjustment potentiometer tap 97.
  • Branch 92 includes voltage dividing resistors 92a and 92b and load resistor 98 in addition to a diode 97 which provides a forward voltage drop that varies with ambient temperature in a manner that is similar to the temperature variation voltage drop across phototransistor 90 thereby negating effects of ambient temperature on the signals presented to lines 93 and 94.
  • output line 88 normally presents a positive potential so long as the light received by phototransistor 90 is below the threshold set by potentiometer tap 97.
  • operational amplifier 86 changes the polarity of output line 88 to negative, thereby detecting the occurrence of the threshold crossing.
  • Potentiometer tap 97 is made adjustable to allow tuning of the particular circuit components involved and also provides for adjustment of the threshold for a particular machine upon its installation to take into account the general room light level within its immediate environment.
  • Delay device 66 can be a simple single shot circuit whose time constant is set to correspond to the time required for a point on photoconductive surface 12 to pass from exposure station 14 to lamp 60. For a machine having predictable constant velocity such a device would work well. Maximum precision can be obtained by providing a displacement emitter operating in synchronism with the drum 11 to provide a delay that is measured directly by the movement of the photoconductive l2.
  • a printer having an image productionmember including a photoconductive surface that is movable along a copy production path, electrostatic imaging, powder image developing, and powder image transfer stations positioned sequentially along said copy production path, said imaging station comprising means for progressively scanning small increments of a light image that are reflected from material positioned on an exposure window onto successive portions of said photoconductive surface, said developing station comprising electrode means capable of developing dense solid black images, said copier further comprising image fixing means for receiving copy sheets to which powder images have been transferred at said transfer station and including a heated surface for contact fusing said powder images to said copy sheets, wherein the improvement comprises: 1
  • said reflected light sensing means including-a light intensity detector supported on said scanning member.
  • a printer as defined in claim 1 further comprising a document hold down cover including a white background piece that is selectively positionable in close adjacency with said exposure window or alternately displaced therefrom, and wherein the improvement further comprises:
  • density altering means comprises an erase lamp positioned along said copy production path between said charging and developing stations, and wherein said light value rise detection responsive means comprises delay means for extinguishing said erase lamp upon the elapse of a period of time following said detection that is a measure of the time required for a point on said photoconductive surface to move from said exposing station to said developing station.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Or Security For Electrophotography (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
US00442533A 1974-02-14 1974-02-14 Copier with leading edge image control Expired - Lifetime US3834807A (en)

Priority Applications (13)

Application Number Priority Date Filing Date Title
US00442533A US3834807A (en) 1974-02-14 1974-02-14 Copier with leading edge image control
IT30511/74A IT1027651B (it) 1974-02-14 1974-12-13 Macchina copiatrice perfezionata
FR7443565A FR2261558B1 (da) 1974-02-14 1974-12-27
CA217,166A CA1035004A (en) 1974-02-14 1974-12-31 Copier with leading edge image control
BE152342A BE824343A (fr) 1974-02-14 1975-01-13 Appareil de reproduction de document comportant des moyens de commande de densite d'images
JP50006010A JPS5925219B2 (ja) 1974-02-14 1975-01-14 複写装置
NL7500896A NL7500896A (nl) 1974-02-14 1975-01-27 Elektrofotografische druk- of kopieerinrichting.
GB383875A GB1447819A (en) 1974-02-14 1975-01-29 Electrophotographic copying machine
IL46565A IL46565A (en) 1974-02-14 1975-02-04 Electrophotographic copying apparatus with leading edge image control
DK50575AA DK142634B (da) 1974-02-14 1975-02-12 Kopieringsapparat til kopiering af forlag af forskellige størrelser.
DE2505833A DE2505833C2 (de) 1974-02-14 1975-02-12 Elektrophotographisches Kopiergerät mit einer Bildrandlöscheinrichtung
CH176975A CH581852A5 (da) 1974-02-14 1975-02-13
SE7501420A SE391591B (sv) 1974-02-14 1975-07-16 Elektrofotografisk kopieringsanordning

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00442533A US3834807A (en) 1974-02-14 1974-02-14 Copier with leading edge image control

Publications (1)

Publication Number Publication Date
US3834807A true US3834807A (en) 1974-09-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00442533A Expired - Lifetime US3834807A (en) 1974-02-14 1974-02-14 Copier with leading edge image control

Country Status (13)

Country Link
US (1) US3834807A (da)
JP (1) JPS5925219B2 (da)
BE (1) BE824343A (da)
CA (1) CA1035004A (da)
CH (1) CH581852A5 (da)
DE (1) DE2505833C2 (da)
DK (1) DK142634B (da)
FR (1) FR2261558B1 (da)
GB (1) GB1447819A (da)
IL (1) IL46565A (da)
IT (1) IT1027651B (da)
NL (1) NL7500896A (da)
SE (1) SE391591B (da)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982116A (en) * 1974-08-06 1976-09-21 Ricoh Co., Ltd. Slit illumination system for copying machine
US3985438A (en) * 1974-02-19 1976-10-12 Minolta Camera Kabushiki Kaisha Exposure control device
US3998541A (en) * 1975-04-18 1976-12-21 Eastman Kodak Company Illumination arrangement providing for interframe flashdown
FR2315712A1 (fr) * 1975-06-24 1977-01-21 Oce Van Der Grinten Nv Appareil copieur
US4046471A (en) * 1975-11-03 1977-09-06 International Business Machines Corporation Dual mode electrophotographic apparatus having dual function printing beam
US4145136A (en) * 1974-12-23 1979-03-20 Canon Kabushiki Kaisha Scanning system for an electrostatic copying apparatus
US4162845A (en) * 1977-09-15 1979-07-31 Xerox Corporation Copier for greater than standard length documents
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
EP0046852A1 (en) * 1980-08-28 1982-03-10 International Business Machines Corporation Electrophotographic copier
US4505575A (en) * 1983-08-26 1985-03-19 Xerox Corporation Non-image erase system for reproduction machines
US4620781A (en) * 1982-10-12 1986-11-04 Canon Kabushiki Kaisha Image processing apparatus for detecting size of the original
US4621920A (en) * 1981-08-03 1986-11-11 Fuji Photo Film Co., Ltd. Preconditioning a photosensitive drum prior to actual photocopying
EP0206602A1 (en) * 1985-06-17 1986-12-30 Mita Industrial Co. Ltd. Electrostatic copying machine
US4655579A (en) * 1984-08-30 1987-04-07 Ricoh Company, Ltd. Multicolored image forming apparatus
US4697916A (en) * 1982-09-25 1987-10-06 Canon Kabushiki Kaisha Image forming apparatus
US4914483A (en) * 1989-04-17 1990-04-03 Eastman Kodak Company Electrostatographic transfer with artifact suppression
US4978996A (en) * 1987-05-06 1990-12-18 Ricoh Company, Ltd. Eraser turn-on control for a copier
US5072259A (en) * 1982-11-20 1991-12-10 Canon Kabushiki Kaisha Image forming apparatus having magnification capabilities with charge removal outside image area
US5200837A (en) * 1989-04-30 1993-04-06 Ricoh Company, Ltd. Digital copier including means for erasing digital image data over a given area, especially suitable for preventing jamming of paper
US5790262A (en) * 1993-05-18 1998-08-04 Tohoku Ricoh Co., Ltd. Image processing device capable of reproducing a book document
US5802215A (en) * 1996-12-17 1998-09-01 Xerox Corporation Quadrant-based density detection for lead edge lightening

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4118119A (en) * 1976-09-02 1978-10-03 Xerox Corporation Facetted edge fadeout reflector
US4255042A (en) * 1979-03-26 1981-03-10 International Business Machines Corporation Light pipe for accurate erasure of photoconductor charge
US4431301A (en) * 1980-03-12 1984-02-14 Tokyo Shibaura Denki Kabushiki Kaisha Electrostatic copying apparatus with means for preventing contamination of reverse side of copying medium
US4463284A (en) * 1981-07-28 1984-07-31 Konishiroku Photo Industry Co., Ltd. Method and apparatus for controlling luminous intensity of fluorescent lamp of reproducing apparatus
JPS63194616U (da) * 1987-05-30 1988-12-14
JPH01198770A (ja) * 1987-10-16 1989-08-10 Ricoh Co Ltd 複写機の制御装置

Citations (1)

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US3135179A (en) * 1959-04-02 1964-06-02 Xerox Corp Xerographic apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE793559A (fr) * 1971-12-30 1973-06-29 Xerox Corp Machine electrostatographique comportant un dispositif de pre-developpement d'exposition

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3135179A (en) * 1959-04-02 1964-06-02 Xerox Corp Xerographic apparatus

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3985438A (en) * 1974-02-19 1976-10-12 Minolta Camera Kabushiki Kaisha Exposure control device
US3982116A (en) * 1974-08-06 1976-09-21 Ricoh Co., Ltd. Slit illumination system for copying machine
US4145136A (en) * 1974-12-23 1979-03-20 Canon Kabushiki Kaisha Scanning system for an electrostatic copying apparatus
US3998541A (en) * 1975-04-18 1976-12-21 Eastman Kodak Company Illumination arrangement providing for interframe flashdown
FR2315712A1 (fr) * 1975-06-24 1977-01-21 Oce Van Der Grinten Nv Appareil copieur
US4095890A (en) * 1975-06-24 1978-06-20 Oce-Van Der Grinten N.V. Xerographic copying apparatus
US4046471A (en) * 1975-11-03 1977-09-06 International Business Machines Corporation Dual mode electrophotographic apparatus having dual function printing beam
US4162845A (en) * 1977-09-15 1979-07-31 Xerox Corporation Copier for greater than standard length documents
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
EP0046852A1 (en) * 1980-08-28 1982-03-10 International Business Machines Corporation Electrophotographic copier
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Also Published As

Publication number Publication date
DK142634C (da) 1981-08-03
DE2505833A1 (de) 1975-08-28
FR2261558B1 (da) 1978-12-22
CA1035004A (en) 1978-07-18
GB1447819A (en) 1976-09-02
SE391591B (sv) 1977-02-21
DK50575A (da) 1975-10-13
IL46565A0 (en) 1975-04-25
DE2505833C2 (de) 1982-12-02
BE824343A (fr) 1975-05-02
FR2261558A1 (da) 1975-09-12
NL7500896A (nl) 1975-08-18
SE7501420L (sv) 1975-08-15
JPS50115832A (da) 1975-09-10
JPS5925219B2 (ja) 1984-06-15
IL46565A (en) 1977-12-30
CH581852A5 (da) 1976-11-15
IT1027651B (it) 1978-12-20
DK142634B (da) 1980-12-01

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