Nothing Special   »   [go: up one dir, main page]

EP0195655A2 - Ajustage automatique des machines à copier électrophotographiques - Google Patents

Ajustage automatique des machines à copier électrophotographiques Download PDF

Info

Publication number
EP0195655A2
EP0195655A2 EP86301991A EP86301991A EP0195655A2 EP 0195655 A2 EP0195655 A2 EP 0195655A2 EP 86301991 A EP86301991 A EP 86301991A EP 86301991 A EP86301991 A EP 86301991A EP 0195655 A2 EP0195655 A2 EP 0195655A2
Authority
EP
European Patent Office
Prior art keywords
photoreceptor
patch
scan
illumination
test
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.)
Granted
Application number
EP86301991A
Other languages
German (de)
English (en)
Other versions
EP0195655B1 (fr
EP0195655A3 (en
Inventor
James Patrick Russell
Ralph Gordon Faull
Wayne Alan Buchar
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.)
Xerox Corp
Original Assignee
Xerox 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 claimed from US06/713,530 external-priority patent/US4618248A/en
Application filed by Xerox Corp filed Critical Xerox Corp
Publication of EP0195655A2 publication Critical patent/EP0195655A2/fr
Publication of EP0195655A3 publication Critical patent/EP0195655A3/en
Application granted granted Critical
Publication of EP0195655B1 publication Critical patent/EP0195655B1/fr
Expired legal-status Critical Current

Links

Images

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
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • G03G15/5033—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor
    • G03G15/5041—Detecting a toner image, e.g. density, toner coverage, using a test patch
    • 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
    • G03G2215/00025—Machine control, e.g. regulating different parts of the machine
    • G03G2215/00029—Image density detection
    • G03G2215/00033—Image density detection on recording member
    • G03G2215/00037—Toner image detection
    • G03G2215/00042—Optical detection

Definitions

  • This invention relates to effectrophotographic printing machines and, more particularly, to a completely automated apparatus and process for establishing basic xerographic parameters at values previously determined to produce optimum output copy quality
  • a photoconductive surface is charged to a substantially uniform potential.
  • the charged portion of the photoconductive surface is exposed to a light image of an original document being reproduced, forming an electrostatic latent image at the photoconductive surface corresponding to the informal areas contained within the original document
  • the electrostatic latent image is subsequently developed by bringing a developer mixture into contact therewith.
  • the developed image is subsequently transferred to an output copy sheet.
  • the powder image on the output sheet is then heated to permanently affix it to the sheet in the image configuration.
  • a primary control objective is to maintain uniform optimum copy quality from machine to machine. This goal has proven difficult to achieve since each machine experiences its own peculiar changes during extended operation. These. changes include aging of the developer mixture, changes in environment variations in the dark development potential, and residual voltage of the photoconductor or photoreceptor surface, a thinning of the photoreceptor surface due to abrasion,- photoreceptor fatigue, exposure lamp illumination variations, and changes in the toner material concentration due to consumption. These variations, singly or cumulatively, have adverse effects on output copy quality that must be identified and compensated for on a continuous basis.
  • the present invention relates to apparatus for optimizing the operation of an electrophotographic printing machine having a corona device for applying a charge to the machine photoreceptor, a scan-illumination optical system for illuminating a document to be copied on a platen surface and for projecting an image of the document along an optical path onto the photoreceptor to form a latent image thereof, a developer unit for applying toner to the belt surface, said apparatus comprising,
  • PIDC photo-induced discharge curve
  • optical test patch generation means comprising part of said scan-illumination system, said patch generation means adapted to form at least a dark development V DDP patch, a second, full illumination V BG patch and a third intermediate development patch on said photoreceptor,
  • a voltmeter for sensing photoreceptor voltage at said test patch areas and for sending representative signals to said memory means
  • first logic means within said controller for analyzing the voltmeter input signals representing the values V DDP and V BG levels, comparing the difference (constant contrast volt age V c ), between these signals and a preset optimum value of V e stored within the memory means and selectively regulating the corona device and the developer unit in an iterative process until convergence is obtained between said difference and said preset value,
  • said logic means being adapted to analyze the voltmeter input signals representing said intermediate development patch, comparing said signal with a preset optimum value stored within the memory means and selectively regulating the illumination output level of said scan-illumination optical system in an iterative process until convergence is obtained between said measured and stored values.
  • the invention relates to an electrophotographic printing machine wherein a document is scanned and an image thereof projected onto a photoreceptor surface, having an optical illumination and scanning system adapted to operate in a first and second mode of operation, said system comprising:
  • said moving means adapted to move said illumination and scan assembly, in a second, test mode of operation, to a first position outside the start of scan position, said motion occuring coincident with the positioning of an opaque occluder in the optical path to form a dark decay test patch at the photoreceptor surface
  • said moving means further adapted to move said illumination and scan assembly from said first position to a second position beneath said target strip
  • an apparatus for automatically adjusting basic xerographic parameters in a periodic initialization mode so as to establish predetermined copy quality and density includes optical means operable in a normal document scanning mode and in a test mode for forming at least four varying density patches on a precharged photoconductive surface, means for sensing the charged levels at three of said density patches, control means having stored therein a set of interrelated electrical values which define a predetermined photo-induced discharge curve (PIDC), said control means adapted to evaluate said sensed charge levels and determine whether they establish convergence with the desired PIDC and, through an iterative process, to vary charge current and exposure levels, until such convergence is realized and means responsive to the density of toner particles deposited on a fourth density patch for controlling the concentration of toner particles in the developer mixture.
  • PIDC photo-induced discharge curve
  • FIG. 1 schematically depicts the various components of an illustrative electrophotographic printing machine incorporating the control system of the present invention therein. It will become apparent from the following discussion that this control system is equally well suited for use in a wide variety of electrophotographic printing machines and is not necessarily limited in its application to the particular embodiment shown herein.
  • the electrophotographic printing machine uses a photoreceptor belt 10 having a photoconductive surface 12 formed on a conductive substrate.
  • belt 12 has characteristics disclosed in U.S. Patent 4,265,990.
  • Belt 10 moves in the indicated direction, advancing sequentially through the various xerographic process stations.
  • the belt is entrained about drive roller 16 and tension rollers 18, 20.
  • Roller 16 is driven by conventional motor means, not shown.
  • a portion of belt 10 passes through charging station A where a corona generating device, indicated generally by the reference numeral 22, charges photoconductive surface 12 to a relatively high, substantially uniform, negative potential.
  • Device 22 comprises a charging electrode 24 and a conductive shield 26.
  • a high voltage supply 30 controlled by a portion of controller 31, is connected to shield 26.
  • a change in the output of power supply 30 causes a change in charging current, l c , and consequently, a change in the charge potential applied to surface 12.
  • Optics assembly 36 contains the optical components which incrementally scan-illuminate the document and project a reflected image onto surface 12 of belt 10. Shown schematically, these optical components comprise an illumination scan assembly 40, comprising illumination lamp 42, associated reflector 43 and full rate scan mirror 4 4 , all three components mounted on a scan carnage 45.
  • the carriage ends are adapted to ride along guide rails (not shown) so as to travel along a path parallel to and beneath, the platen. Lamp 42 illuminates an incremental line portion of document 32.
  • the reflected image is reflected by scan mirror 44 to comer mirror assembly 46 on a second scan carriage 46A moving at 1/2 the rate of mirror 44.
  • the document image is projected through lens 47 and reflected by a second comer mirror 48 and belt mirror 50, both moving at a predetermined relationship so as to precess the projected image, while maintaining the required rear conjugate onto surface 12 to form thereon an electrostatic latent image corresponding to the informational areas contained within original document 32.
  • Adjustable illumination power supply 51 controlled by a portion of controller 31, supplies power to lamp 42.
  • the optics assembly 36 besides operating in a document scanning mode, is also used in the automatic setup mode of the present invention, to generate and project four alternating density patches onto the centerline of the belt 10 for purposes to be described more fully below.
  • Voltmeter 52 Positioned between exposure station B and development station C, and adjacent to surface 12, is electrostatic voltmeter 52.
  • Voltmeter 52 preferably is capable of measuring either positive or negative potentials and utilizes ac circuitry requiring no field calibration.
  • Voltmeter 52 in the automatic setup mode, generates a first signal proportional to the dark decay potential V o on photoconductive surface 12.
  • the dark development potential is the charge at surface 12 after charging and exposure reflected from an opaque object.
  • the voltmeter also generates a second signal proportional to background potential V B , on the photoreceptor surface.
  • the background potential is the charge on the photoreceptor after exposure with light reflected from a white object
  • Controller 31 operates upon these values, comparing them to values related to a desired output quantity in the controller memory. Adjustments are made by the controller to the charging and development bias voltage and to the illumination power supply in an iterative process described in further detail below:
  • discrete patch generator 53 is a calibrated LED light source which is energized in one of two modes of operation.
  • a dedicated digital input provides for LED energization at a high fixed level. This mode is used primarily for erasing test patch areas generated during the setup procedures.
  • an analog reference input to the generator 53 provides for energization of the LEDs so as to generate a variable light intensity for use in toner control in several contrast modes as described in greater detail below.
  • a magnetic brush development system advances an insulating development material into contact with the electrostatic latent image.
  • magnetic brush development system 5 4 includes a developer roller 56 within a housing. 58..
  • Roller 56 transports. a .brush .of developer material comprising magnetic carrier granules and toner particles into contact with belt 10.
  • Roller 56 is positioned so that the brush of developer material deforms belt 10 in an arc with the belt conforming, at least partially, to the configuration of the developer material.
  • the thickness of the layer of developer material adhering to developer roller 56 is adjustable.
  • Roller 56 is biased by voltage source 57 to a voltage level V D .
  • the electrostatic latent image attracts the toner particles from the carrier granules forming a toner powder image on photoconductive surface 12.
  • the detailed structure of the magnetic brush development system is more fully disclosed in U.S. Patent 4,397,264.
  • a toner particle dispenser indicated generally by the reference numeral 60 provides additional toner particles to housing 58 for subsequent use by developer roller 56.
  • Toner dispenser 60 includes a container for storing a supply of toner particles therein and means (not shown) for introducing the particles into developer housing 58.
  • a motor 62 when energized, initiates the operation of dispenser 60.
  • Infrared densitometer 64 positioned adjacent belt 10 and located between developer station C and transfer station D, directs infrared light onto surface 12 upon appropriate signals from the controller 31.
  • the ratio of reflected light on a developed area to that of a bare area is an indication of toner patch developability.
  • the densitometer generates output signals and sends them to controller 31 through appropriate conversion circuitry.
  • the controller operates upon these signals and sends appropriate output signals to motor 62 to control dispensing of toner particles.
  • Densitometer 64 is also used to periodically measure the light rays reflected from the bare photoconductive surface - (i.e. without developed toner particles) to provide a reference level for calculation of the signal ratios.
  • an output copy sheet 66 taken from a supply tray 67 is moved into contact with the toner powder image at transfer station D.
  • the support material is conveyed to station D by a pair of feed rollers 68, 70.
  • Transfer station D includes a corona generating device 71 which sprays ions onto the backside of sheet 66, thereby attracting the toner powder image from surface 12 to sheet 66.
  • the sheet advances to fusing station E where a fusing roller assembly 72 affixes the transferred powder image.
  • sheet 66 advances to an output tray (not shown) for subsequent removal by the operator.
  • the residual toner particles and the toner particles of developed test patch areas are removed at cleaning station F.
  • a discharge lamp floods surface 12 with light to dissipate any residual charge remaining thereon prior to the charging thereof for the next imaging cycle.
  • PIDC photo-induced discharge curve
  • controller 31 consists of Input/Output Board 80, and master control board 82, Input/Output processor 86 and a serial bus controller 88.
  • Input signals from the densitometer 64, voltmeter 52 and patch generator 53 are converted by I/O board 80; sent to I/O processor 86 and then to processor 84. Output signals are sent to adjust the corona generator, system illumination, toner dispenser and development bias via processor 86. Operation of the optical scanning system is controlled by processor 84 via controller 88.
  • the master control processor is an Intel Model 8085 which can be programmed to perform the described iterative functions, using the algorithms set forth in the Appendix. Incorporation of these algorithms into a larger and central unit is a procedure well understood by those skilled in the art.
  • the automatic setup mode is initiated by applying initial power application to the machine.
  • the sequence of operations occurring thereafter is shown with reference to Figure 4a, 4b.
  • Figure 4a, 4b is a flow chart sequence of these operations.
  • Figure 5 is a side view schematic drawing of the scan carriage at different density patch generating positions.
  • Figure 6 is a time vs. voltage plot of the test patch generation sequence, and
  • Figure 7 is a top view of belt 10 showing the imaged patched zones.
  • Figure 9 is a flow chart of the test patch generator and machine functions. Referring to Figures 4a, 5, and 6, once machine power is turned on, the photoreceptor moves through a first cycle of operation at the system process speed. Scan carriage 45 moves to the home park position. Carriage 45, in this position is shown to the left of the platen in Figure 5. The components are shown dotted. Scan lamp 42 is energized at the normal lamp power level used during the preceding operational interval.
  • An opaque occluder 90 is positioned in the optical path at a point above the belt 10 surface 12, thus preventing light from falling on the surface in an area corresponding to the occluder.
  • a first test patch 100 shown formed on the belt centerline in Figure 7 is therefore at the dark decay charging level V DDP .
  • Carriage 45 is then moved to the right, scanning at a constant velocity, until it reaches park position 1 past the end of scan position (shown in solid line in Figure 5). At this position, a 0.3 density target strip 92 centrally overlies the scan carriage.
  • lamp 42 output is doubled so as to form a second patch area 102 conforming in size to strip 92 representing a 100% transmission, completely discharged strip at background voltage level, V BG .
  • Electrostatic voltmeter 52 shown in Figure 1, is used to directly sense photoreceptor voltage at the test patch areas 100, 102, 104, 106.
  • the voltmeter is positioned approximately 3 mm from the belt surface.
  • FIG 4b shows the functional flow diagram for the voltmeter readings and the related microprocessor control operation.
  • the voltmeter measures each of test patch charge levels on successive belt cycles.
  • Signals representing the voltage at patch 100 (V CDP ), patch 102 (V BG ) and patch 104 (V O . 3D ) are sent to the control processor 84 through the associated I/O circuitry and temporarily stored therein.
  • the difference between V DDP and V SG is computed by logic means within the controller and a signal, representing this value and designated constant contrast voltage (V c ) is generated. This signal is compared to a preset V CSET (V S ).
  • Vc Vs, (no convergence)
  • a signal is generated within the processor and sent to change the bias (V GRID ) on the charge electrode 24 ( Figure 1) thereby changing the value of charge current l c and the value of V DDP .
  • Signals are also sent to patch generator 53 to erase the previously generated patch areas.
  • Scan carriage 45 then repeats the sequence described with respect to Figures 4a and 5, beginning at the home park position and continuing to park position 2.
  • the newly formed patches are again read by the voltmeter and compared to processor 84 (Fig. 4b).
  • This process is an iterative one governed by a control algorithm set forth in Appendix; the process is continued until the measured value of V c conforms to Vs. At this point, the value of V DDP and V BG conforms to the PIDC for the machine.
  • a second iterative process is controlled by logic means within processor 8 4 , which compares the measured values of the V 0.30 patch to a preset V 0.3DS value.
  • System illumination' is varied to achieve identity of the set and measured values; convergence establishes a third point on the PIDC.
  • processor 84 measures the difference between the test value of V. 3D and the V .3DS , set into the processor memory. If V 0.30 V . 3DS (no convergence) processor 84 sends a signal to lamp power supply 51 to vary the output of lamp 42 and to patch generator 53 to erase the V. 3D patch 104.
  • Scan carriage 45 repeats the process beginning at the home position 1 and the voltmeter again measures the charge at patch 104 sending the output signal to the processor.
  • This iterative process is controlled by a second algorithm provided in the Appendix.
  • V O . 3D and V O . 3DS Upon convergence of V O . 3D and V O . 3DS , the value of E o, system exposure level, is stored. Convergence has assured that the 0.3D voltage also falls on the PIDC curve shown in Figure 2. Thus, the charge at the high (V DDP ), low (V BG ) and intermittent levels all lie along the predetermined PIDC, thus ensuring that the copy quality will be consistent with machine population utilizing that particular PIDC.
  • Both patches 108 and 110 are developed at development station C ( Figure 1) and pass beneath densitometer 64. As illustrated in Figure 1 and Figure 11, the densitometer detects the density of the developed test area and produces electrical output signals indicative thereof. Thus the densitometer produces output signals proportional to the toner mass deposited on the V 0.7D patch 108 and the V DPG patch 110. These signals are conveyed to processor 84 through conversion circuitry shown in Figure 3. Processor 83 compares the two values and if there is a difference (Voss ) a signal is generated which changes the voltage level at the patch generator. The developed patches are cleaned at cleaning station F, Figure 1, and patches 108 and 110 are laid down as previously described, developed and again measured by densitometer 64. Adjustments are made to patch generator 53 in an iterative process gov- emed by the algorithm set forth in the Appendix until the two measured values are equal. When this occurs, the patch generator is property calibrated to the system parameters and value representing V PG is stored.
  • the final task of the setup procedure is to adjust the developer parameters, if necessary. An adjustment may not be necessary since the toner concentration level is monitored during normal operation and toner periodically added, as is known in the art Therefore, a previous operation cycle should have left the toner concentration in a proper operating condition.
  • the present setup procedure ensures proper toner concentrations by comparing the last V DDS value measured and stored by processor 84 with a previously stored V DSS value representing a value of V DSS which if exceeded, indicates a low level of toner concentration is present As shown in Figure 9, if the difference between the two exceeds a set value, processor 84 activates toner dispenser motor 63 causing toner dispenser 60 to discharge toner particles into toner container 62.
  • Carriage 45 forms a subsequent V O . 70 , V DDP patch.
  • Densitometer 64 measures the respective density and processor 82 determines a new V DSS value as described above. The new V DSS is compared with the V DSS set, the process repeated, if necessary. Once the values are within the predefined difference range, toner developability parameters have been defined and the automatic setup procedure is terminated. Normal machine operation then begins.
  • vbiasc linfid is the cleaning field in terms of developer bias. There is a value for each of the normal copy modes. During setup the value is for CN.
  • the particular mode is found in the Table "multinational Standard Modes" at the end of the Appendix.
  • the illumination control voltage adjustment for the exposure setup is expressed in terms of bit count as follows:
  • the pre-developability patch generator adjustment is as follows:

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Or Security For Electrophotography (AREA)
EP19860301991 1985-03-18 1986-03-18 Ajustage automatique des machines à copier électrophotographiques Expired EP0195655B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US71337185A 1985-03-18 1985-03-18
US713530 1985-03-18
US06/713,530 US4618248A (en) 1985-03-18 1985-03-18 Test patch generation utilizing system scan optics
US713371 1985-03-18

Publications (3)

Publication Number Publication Date
EP0195655A2 true EP0195655A2 (fr) 1986-09-24
EP0195655A3 EP0195655A3 (en) 1987-04-01
EP0195655B1 EP0195655B1 (fr) 1991-05-08

Family

ID=27108989

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860301991 Expired EP0195655B1 (fr) 1985-03-18 1986-03-18 Ajustage automatique des machines à copier électrophotographiques

Country Status (3)

Country Link
EP (1) EP0195655B1 (fr)
JP (1) JPS61213865A (fr)
DE (1) DE3679095D1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3936255A1 (de) * 1988-10-31 1990-05-03 Toshiba Kk Bilderzeugungsgeraet mit anfangseinstellsystem
EP0531171A2 (fr) * 1991-09-05 1993-03-10 Xerox Corporation Recalcul des paramètres électrostatiques dans un appareil xérographique de formation d'images
EP0589131A2 (fr) * 1992-09-24 1994-03-30 Kabushiki Kaisha Toshiba Appareil et méthode de formation d'images
EP0589135A2 (fr) * 1992-09-24 1994-03-30 Kabushiki Kaisha Toshiba Appareil de formation d'images et procédé de la fabrication
EP0599294A2 (fr) * 1992-11-27 1994-06-01 Sharp Kabushiki Kaisha Dispositif de formation d'image
EP0743569A2 (fr) * 1994-12-22 1996-11-20 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'utilisation et de calibrage
EP0789322A3 (fr) * 1996-01-08 1998-05-06 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'usage, de calibration et autres
EP1107070A2 (fr) * 1999-12-03 2001-06-13 Xerox Corporation Procédé et dispositif pour l'estimation adaptive de la surface unie noire dans un dispositif xérographique

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2546261B2 (ja) * 1987-03-13 1996-10-23 ミノルタ株式会社 複写機
JPH02296266A (ja) * 1989-05-10 1990-12-06 Canon Inc 画像形成装置
US5227270A (en) * 1991-09-05 1993-07-13 Xerox Corporation Esv readings of toner test patches for adjusting ird readings of developed test patches

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2741713A1 (de) * 1976-09-17 1978-03-23 Canon Kk Verfahren und vorrichtung zur stabilisierung eines elektrostatischen ladungsbildes
US4215930A (en) * 1977-02-23 1980-08-05 Ricoh Company, Limited Method of maintaining the correct conditions of an electrophotographically duplicated image
DE3221618A1 (de) * 1981-06-11 1982-12-30 Canon K.K., Tokyo Bilderzeugungsgeraet
DE3304966A1 (de) * 1982-02-12 1983-09-01 Ricoh Co., Ltd., Tokyo Verfahren zum steuern eines bildschwaerzungsgrades
DE3340959A1 (de) * 1982-11-11 1984-05-17 Ricoh Co., Ltd., Tokio/Tokyo Verfahren zum steuern eines schwaerzungsgrades

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5589859A (en) * 1978-12-28 1980-07-07 Canon Inc Method and apparatus for forming stable image
US4348099A (en) * 1980-04-07 1982-09-07 Xerox Corporation Closed loop control of reproduction machine
JPS56161554A (en) * 1980-05-19 1981-12-11 Fuji Xerox Co Ltd Control device for electronic copying machine
JPS5749955A (en) * 1980-09-11 1982-03-24 Canon Inc Electrophotographic device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2741713A1 (de) * 1976-09-17 1978-03-23 Canon Kk Verfahren und vorrichtung zur stabilisierung eines elektrostatischen ladungsbildes
US4215930A (en) * 1977-02-23 1980-08-05 Ricoh Company, Limited Method of maintaining the correct conditions of an electrophotographically duplicated image
DE3221618A1 (de) * 1981-06-11 1982-12-30 Canon K.K., Tokyo Bilderzeugungsgeraet
DE3304966A1 (de) * 1982-02-12 1983-09-01 Ricoh Co., Ltd., Tokyo Verfahren zum steuern eines bildschwaerzungsgrades
DE3340959A1 (de) * 1982-11-11 1984-05-17 Ricoh Co., Ltd., Tokio/Tokyo Verfahren zum steuern eines schwaerzungsgrades

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5166730A (en) * 1988-10-31 1992-11-24 Kabushiki Kaisha Toshiba Image forming apparatus having automatic initial adjustment system
DE3936255A1 (de) * 1988-10-31 1990-05-03 Toshiba Kk Bilderzeugungsgeraet mit anfangseinstellsystem
EP0531171A3 (fr) * 1991-09-05 1994-08-03 Xerox Corp
EP0531171A2 (fr) * 1991-09-05 1993-03-10 Xerox Corporation Recalcul des paramètres électrostatiques dans un appareil xérographique de formation d'images
EP0589131A3 (en) * 1992-09-24 1994-08-24 Toshiba Kk Image forming apparatus and image forming method
EP0589135A2 (fr) * 1992-09-24 1994-03-30 Kabushiki Kaisha Toshiba Appareil de formation d'images et procédé de la fabrication
EP0589131A2 (fr) * 1992-09-24 1994-03-30 Kabushiki Kaisha Toshiba Appareil et méthode de formation d'images
EP0599294A2 (fr) * 1992-11-27 1994-06-01 Sharp Kabushiki Kaisha Dispositif de formation d'image
EP0599294A3 (en) * 1992-11-27 1994-06-29 Sharp Kk Image forming apparatus.
US5477308A (en) * 1992-11-27 1995-12-19 Sharp Kabushiki Kaisha Image forming apparatus having an image-quality correction function
EP0833211A1 (fr) * 1992-11-27 1998-04-01 Sharp Kabushiki Kaisha Appareil de formation d'images
EP0743568A2 (fr) * 1994-12-22 1996-11-20 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'utilisation et de calibration
EP0743569A2 (fr) * 1994-12-22 1996-11-20 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'utilisation et de calibrage
EP0743569A3 (fr) * 1994-12-22 1998-05-06 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'utilisation et de calibrage
EP0743568A3 (fr) * 1994-12-22 1998-11-25 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'utilisation et de calibration
EP0789322A3 (fr) * 1996-01-08 1998-05-06 Hewlett-Packard Company Pièce de rechange à mémoire intégrée pour des données d'usage, de calibration et autres
EP1107070A2 (fr) * 1999-12-03 2001-06-13 Xerox Corporation Procédé et dispositif pour l'estimation adaptive de la surface unie noire dans un dispositif xérographique
EP1107070A3 (fr) * 1999-12-03 2005-03-16 Xerox Corporation Procédé et dispositif pour l'estimation adaptive de la surface unie noire dans un dispositif xérographique

Also Published As

Publication number Publication date
EP0195655B1 (fr) 1991-05-08
JPS61213865A (ja) 1986-09-22
EP0195655A3 (en) 1987-04-01
DE3679095D1 (de) 1991-06-13

Similar Documents

Publication Publication Date Title
US4647184A (en) Automatic setup apparatus for an electrophotographic printing machine
US4348099A (en) Closed loop control of reproduction machine
US5436705A (en) Adaptive process controller for electrophotographic printing
US4341461A (en) Development control of a reproduction machine
US4847659A (en) Apparatus for controlling toner replenishment in electrostatographic printer
US5887221A (en) Signature sensing for optimum toner control with donor roll
EP0071746A2 (fr) Moyen et procédé de contrôle pour une copieuse électrostatique
US5678131A (en) Apparatus and method for regulating toning contrast and extending developer life by long-term adjustment of toner concentration
EP0308491A1 (fr) Commande de traitement dynamique pour machines electrostatographiques.
GB2097965A (en) Control apparatus for electrostatography
US4618248A (en) Test patch generation utilizing system scan optics
US5649266A (en) In-station calibration of toner concentration monitor and replenisher drive
EP0195655B1 (fr) Ajustage automatique des machines à copier électrophotographiques
CA2076765C (fr) Lecture de toner au moyen d'un voltmetre electrostatique pour la densitometrie infrarouge
US4141645A (en) Toner concentration monitor
JPS63244083A (ja) 電子写真式複写機及びその着色粒子排出制御装置
US6885833B2 (en) Reduction of banding and mottle in electrophotographic systems
US5164776A (en) Apparatus and method for correcting the voltage on a photoconductive device
EP0903642B1 (fr) Procédé pour contrôler la concentration de toner
US6006047A (en) Apparatus for monitoring and controlling electrical parameters of an imaging surface
EP0871324B1 (fr) Décharge photo-induite pour xérographie
US5016050A (en) Xerographic setup and operating system for electrostatographic reproduction machines
US5122842A (en) Color electrostatography process control by way of toner development characteristics
US5521677A (en) Method for solid area process control for scavengeless development in a xerographic apparatus
US4912508A (en) Automatic background control for an electrostatic copier

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19870924

17Q First examination report despatched

Effective date: 19890307

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB NL

REF Corresponds to:

Ref document number: 3679095

Country of ref document: DE

Date of ref document: 19910613

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20030310

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20030312

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20030327

Year of fee payment: 18

Ref country code: DE

Payment date: 20030327

Year of fee payment: 18

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040318

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20041001

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20041001

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20040318

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20041130

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20041001

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST