EP0109722A1 - Procédé et appareil pour l'ajustage automatique du potentiel d'une couche photosensible - Google Patents

Procédé et appareil pour l'ajustage automatique du potentiel d'une couche photosensible Download PDF

Info

Publication number
EP0109722A1
EP0109722A1 EP19830201650 EP83201650A EP0109722A1 EP 0109722 A1 EP0109722 A1 EP 0109722A1 EP 19830201650 EP19830201650 EP 19830201650 EP 83201650 A EP83201650 A EP 83201650A EP 0109722 A1 EP0109722 A1 EP 0109722A1
Authority
EP
European Patent Office
Prior art keywords
photosensitive layer
electrometer
potential
corotron
target value
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.)
Withdrawn
Application number
EP19830201650
Other languages
German (de)
English (en)
Inventor
Gerben Simon Hoeksma
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.)
Nederlandsche Apparatenfabriek NEDAP NV
Original Assignee
Nederlandsche Apparatenfabriek NEDAP NV
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
Application filed by Nederlandsche Apparatenfabriek NEDAP NV filed Critical Nederlandsche Apparatenfabriek NEDAP NV
Publication of EP0109722A1 publication Critical patent/EP0109722A1/fr
Withdrawn legal-status Critical Current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
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0266—Arrangements for controlling the amount of charge
    • 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
    • G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
    • G03G15/0291—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device

Definitions

  • the invention relates to a method of adjusting the potential of a photosensitive layer, in which said layer is moved along a corotron energized by a high voltage supply and is charged thereby, as well as to an apparatus for applying the method.
  • Such a method and apparatus are applied e.g. in copying apparatus, in which, according to the known technique, the high voltage supply supplies a charging current to a corotron.
  • a photosensitive layer applied e.g. on a drum rotating in operation, said layer being charged by the corotron by means of corona discharge.
  • the photosensitive layer thus charged is subsequently exposed via a document to be reproduced. Since, upon exposure of the photosensitive layer, charge is leaking away in a manner corresponding to the intensity of the incident light, and therefore to the document to be reproduced, there is produced an electrostatic image pattern, which can be transferred onto an image carrier, such as paper, by any of the methods known for that purpose.
  • a method of the above described type is characterized in that the potential of a corotron-charged portion of the photosensitive layer is measured contactlessly by means of an electrometer device; that the value measured is compared with a predetermined target value, after which, if the difference between the value measured and the target value lies beyond predetermined limits, and adjustment parameter of the high voltage supply is changed; and that after a period of time minimally equal to the time required for moving the portion of the photosensitive layer charged with the new setting of the high voltage supply from the corotron to the electrometer, the potential of the photosensitive layer is measured again and compared with the target value, after which, if the difference between the target value and the value measured lies beyond predetermined limits, the said adjustment parameter is again changed, which cycle is repeated as long as the difference between the target value and the value measured lies within the predetermined limits.
  • An apparatus for applying the method is characterized, according to the invention, by an electrometer device along which the photosensitive layer, after having been charged by the corotron, is moved, which electrometer device measures contactlessly the potential of the photosensitive layer; a comparator for comparing the value measured of the potential with a predetermined target value, which comparator transmits an output signal dependent on the difference between the value measured and the target value and which is supplied to the high voltage supply in order to control an adjustment parameter of the high voltage supply.
  • Fig. 1 shows a high voltage supply 1 of a conventional type, the output of which is connected to a corotron 3.
  • the corotron 3 comprises, as is conventional, a housing 5, which is open at one end and wherein there extends a conductor 4. The open end faces the photosensitive layer 6, which can be charged by a corona discharge originating from the conductor 5.
  • the photosensitive layer moves along the corotron, thereby being charged along the entire surface.
  • the direction of movement of the photosensitive layer is indicated by an arrow 7.
  • the photosensitive layer is charged as uniformly as possible.
  • the photosensitive layer after having been charged by the corotron 3, moves along an electrometer 8, by means of which the potential of the photosensitive layer is measured contactlessly.
  • the potential measured can then be compared with a predetermined target value and, depending on the difference between the two values, a setting signal can be supplied to the high voltage supply 1 through a line 9.
  • a setting signal can be supplied to the high voltage supply 1 through a line 9.
  • the electrometer After the photosensitive layer has been set in motion at the nominal speed v, and it has been communicated for instance by means of a control signal 10, originating from a machine control unit 11, to the electrometer 8 that the adjustment procedure is to be initiated, the electrometer transmits the best estimate of the required charging current to be passed through the conductor 5 to the high voltage supply 1, which is switched on e.g. through a control signal 12 originating from the control unit 11. After an interval which is minimally equal to the time required for conducting the corotron-charged portion of the photosensitive layer to the electrometer, the electrometer measures the actual potential of the photosensitive layer and again gives the best estimate for the adjustment of the high voltage supply, based on the actual value of the potential of the photosensitive layer and the estimated required change of the setting of the high voltage supply.
  • the potential of the photosensitive layer is again measured and, if necessary, the high voltage supply is readjusted.
  • the electrometer transmits a signal to the control unit 11 through a line 13 and the adjustment procedure can be terminated.
  • the electrometer retains the setting value for the charging current, determined in the above described manner, and this charging current is supplied to the corotron in the next process. After some time, the adjustment procedure can be repeated.
  • the electrometer is preferably of the known per se type with rotary chopper blade.
  • the electrometer is connected to ground and can be supplied from a d-c voltage available in the machine.
  • a rotary chopper blade 14 periodically covers a collecting electrode 15. In non-covered condition, the potential of the photosensitive layer 16 induces charge onto the electrode 15. This alternating charge is converted by an input stage 17 with a virtual earth input into an a-c voltage which, after a possible amplification in an amplifier stage 18, is converted by a phase-responsive detector 19, into a d-c voltage.
  • the phase detector 19 requires a phase signal 20 that is in synchronism with the rotary chopper 14.
  • the control signal 10 starts a timer 21 which transmits a signal to comparator circuitry 23 through a line 22.
  • said circuitry determines the best estimate for the new setting of the charging current of the corotron.
  • a signal is again transmitted and the adjustment procedure is continued, as described in the above, until the potential of the photosensitive layer approximates the desired value sufficiently accurately and the electrometer communicates this to the control unit 11 e.g. by means of a signal through the line 13, after which the adjustment procedure can be terminated.
  • the electrometer-chopper blade and the subsequent circuitry is connected to a reference voltage source 27 carrying the same voltage U ref as the desired nominal value of the voltage of the photosensitive layer.
  • This electrometer functions, for the rest, analogously to the above described electrometer and comprises an amplifier 17 with a virtual earth input, possibly an amplifier stage 18, and a phase-responsive detector 19 receiving a phase signal 20.
  • the phase-responsive detector transmits a signal through a galvanic separation element 28, to comparator circuitry 29, which signal is proportional to the difference between the potential of the photosensitive layer 16 and the potential of the voltage source 27.
  • the timer 21 has the same function as described in the above, and the comparator circuitry 29 generates the setting value 9 and the feedback signal 13, as described in the above.
  • the advantage of this modified embodiment is that the actual potential of the photosensitive layer, after termination of the adjustment procedure, does not depend either on the distance between the photosensitive layer and the electrometer, or on the surface area of the electrode 15, or on the speed of the chopper, or on the gain factor of the electrometer-amplifier stages, so that the accuracy of the potential set is determined primarily by the accuracy of the reference voltage source, thus enabling a very simple calibration of this system, combined with a very good long-term stability thereof.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
EP19830201650 1982-11-19 1983-11-18 Procédé et appareil pour l'ajustage automatique du potentiel d'une couche photosensible Withdrawn EP0109722A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8204520 1982-11-19
NL8204520 1982-11-19

Publications (1)

Publication Number Publication Date
EP0109722A1 true EP0109722A1 (fr) 1984-05-30

Family

ID=19840625

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830201650 Withdrawn EP0109722A1 (fr) 1982-11-19 1983-11-18 Procédé et appareil pour l'ajustage automatique du potentiel d'une couche photosensible

Country Status (2)

Country Link
EP (1) EP0109722A1 (fr)
JP (1) JPS59140468A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4002013A1 (de) * 1989-03-23 1990-09-27 Toshiba Kawasaki Kk Vorrichtung zum einstellen einer ausgangsleistung von aufladeeinheiten bei einem bilderzeugungsgeraet
EP0735439A1 (fr) * 1995-03-28 1996-10-02 Philips Patentverwaltung GmbH Appareil d'enregistrement par rayons X comprenant un photoconducteur et un dispositif de chargement

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3934141A (en) * 1974-07-03 1976-01-20 Xerox Corporation Apparatus for automatically regulating the amount of charge applied to an insulating surface
US3944354A (en) * 1974-09-06 1976-03-16 Eastman Kodak Company Voltage measurement apparatus
DE2007728B2 (de) * 1969-02-26 1977-10-20 Xerox Corp, Rochester, N Y (V St A) Verfahren und vorrichtung zur auswertung der verteilung der elektrischen ladung auf einer elektrostatisch geladenen schicht
GB1533311A (en) * 1975-04-28 1978-11-22 Xerox Corp Electrostatographic diagnostics system
US4134137A (en) * 1976-11-01 1979-01-09 Xerox Corporation Single wire microelectrometer imaging system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2007728B2 (de) * 1969-02-26 1977-10-20 Xerox Corp, Rochester, N Y (V St A) Verfahren und vorrichtung zur auswertung der verteilung der elektrischen ladung auf einer elektrostatisch geladenen schicht
US3934141A (en) * 1974-07-03 1976-01-20 Xerox Corporation Apparatus for automatically regulating the amount of charge applied to an insulating surface
US3944354A (en) * 1974-09-06 1976-03-16 Eastman Kodak Company Voltage measurement apparatus
GB1533311A (en) * 1975-04-28 1978-11-22 Xerox Corp Electrostatographic diagnostics system
US4134137A (en) * 1976-11-01 1979-01-09 Xerox Corporation Single wire microelectrometer imaging system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4002013A1 (de) * 1989-03-23 1990-09-27 Toshiba Kawasaki Kk Vorrichtung zum einstellen einer ausgangsleistung von aufladeeinheiten bei einem bilderzeugungsgeraet
US5161084A (en) * 1989-03-23 1992-11-03 Kabushiki Kaisha Toshiba Apparatus for controlling an output of chargers for use in image forming apparatus
EP0735439A1 (fr) * 1995-03-28 1996-10-02 Philips Patentverwaltung GmbH Appareil d'enregistrement par rayons X comprenant un photoconducteur et un dispositif de chargement
US5686732A (en) * 1995-03-28 1997-11-11 U.S. Philips Corporation X-ray apparatus comprising a photoconductor and a charging device

Also Published As

Publication number Publication date
JPS59140468A (ja) 1984-08-11

Similar Documents

Publication Publication Date Title
CN100507729C (zh) 图像形成装置及方法
EP0001886B1 (fr) Système pour charger le dispositif photoconducteur dans une machine xérographique
US4378153A (en) Electronic duplicator
EP0269695B1 (fr) Dispositif de production d'echantillons
CA2076765C (fr) Lecture de toner au moyen d'un voltmetre electrostatique pour la densitometrie infrarouge
US4618249A (en) Corona-charging apparatus
US5684685A (en) High voltage power supply for image transfer and image forming apparatus using the same
EP0109722A1 (fr) Procédé et appareil pour l'ajustage automatique du potentiel d'une couche photosensible
US5138378A (en) Electrostatic target recalculation in a xerographic imaging apparatus
EP0133319A1 (fr) Dispositif d'exposition automatique
DE69414426T2 (de) Prozesssteuervorrichtung eines elektrophotographischen Gerätes
US4619520A (en) Variable magnification electrophotographic copying apparatus
US5285241A (en) Maintaining precise electrostatic control using two ESVs
US4857959A (en) Method and apparatus of charging for transfer in electrophotograph device
GB2102970A (en) Voltage measuring
US5534977A (en) Image forming apparatus having a function to charge a photoreceptor drum at an appropriate potential
US4228480A (en) Electrophotographic apparatus with improved corona charging
CA2076822C (fr) Convergence de mise sous tension du dispositif electrostatique d'un appareil d'imagerie a trois niveaux
CA2076838C (fr) Systeme de commande de la variation du niveau du noir utilisant deux voltmetres electrostatiques
JPH01123267A (ja) 電子写真装置
JPH1039618A (ja) 現像装置及び電子写真印刷装置
EP0531063A2 (fr) Contrôle de la perte de charge d'une zone image dans un appareil de formation d'images à trois niveaux
US6034368A (en) AC corona current regulation
US6381426B1 (en) Automatic gain control for electrostatic voltmeters
JP2658017B2 (ja) 感光体の表面電位制御装置

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

Designated state(s): AT BE CH DE FR GB IT LI NL SE

17P Request for examination filed

Effective date: 19841023

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19860122

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HOEKSMA, GERBEN SIMON