EP0438303B1 - Bilderzeugungsgerät mit Trägermitteln für ein Übertragungsblatt - Google Patents

Bilderzeugungsgerät mit Trägermitteln für ein Übertragungsblatt Download PDF

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Publication number
EP0438303B1
EP0438303B1 EP19910300343 EP91300343A EP0438303B1 EP 0438303 B1 EP0438303 B1 EP 0438303B1 EP 19910300343 EP19910300343 EP 19910300343 EP 91300343 A EP91300343 A EP 91300343A EP 0438303 B1 EP0438303 B1 EP 0438303B1
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EP
European Patent Office
Prior art keywords
transfer
voltage
transfer sheet
image
forming apparatus
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
EP19910300343
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English (en)
French (fr)
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EP0438303A2 (de
EP0438303A3 (en
Inventor
Takao C/O Canon Kabushiki Kaisha Aoki
Yujiro C/O Canon Kabushiki Kaisha Ando
Shinkichi C/O Canon Kabushiki Kaisha Takahashi
Eihiro C/O Canon Kabushiki Kaisha Sakaki
Fumihiro C/O Canon Kabushiki Kaisha Ueno
Toshiaki C/O Canon Kabushiki Kaisha Miyashiro
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.)
Canon Inc
Original Assignee
Canon Inc
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Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0438303A2 publication Critical patent/EP0438303A2/de
Publication of EP0438303A3 publication Critical patent/EP0438303A3/en
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Publication of EP0438303B1 publication Critical patent/EP0438303B1/de
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
    • G03G15/65—Apparatus which relate to the handling of copy material
    • G03G15/6532—Removing a copy sheet form a xerographic drum, band or plate
    • G03G15/6535—Removing a copy sheet form a xerographic drum, band or plate using electrostatic means, e.g. a separating corona
    • 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
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/1665—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat
    • G03G15/167—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer by introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat at least one of the recording member or the transfer member being rotatable during the transfer
    • 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
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0167—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member
    • G03G2215/0174—Apparatus for electrophotographic processes for producing multicoloured copies single electrographic recording member plural rotations of recording member to produce multicoloured copy
    • 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
    • G03G2215/16—Transferring device, details
    • G03G2215/1604—Main transfer electrode
    • G03G2215/1619—Transfer drum

Definitions

  • an electrostatic transfer process such as a bias roller transfer process or a corona transfer process has been generally utilized.
  • the toner image is transferred onto the transfer sheet, by applying the transfer bias voltage having a polarity opposite to that of the charge of the toner image formed on the image bearing member to a transfer roller having a conductive layer acting as a transfer sheet bearing member.
  • a transfer roller having a conductive layer acting as a transfer sheet bearing member.
  • an endless belt having the conductive layer may be used.
  • a dielectric film such as a polyester film is used as the transfer sheet bearing member
  • a transfer drum is formed by wrapping the film on a cylinder having a large undercut on its peripheral surface, and the toner image is transferred onto the transfer sheet by applying the corona discharge to the film from the inside of the transfer drum.
  • an endless belt made of a dielectric film may be used.
  • the bias roller transfer process has a structural advantage that the durability of the structure thereof is excellent and the structure is simple, in comparison with the corona transfer process; however, since the bias voltage is applied to the whole transfer roller, it is difficult to control the removal of the charge in the area where the transfer sheet is separated from the transfer roller, thus causing the scattering of the toner image easily.
  • Another concern of the present invention is to provide an image forming apparatus which can effectively remove the charge from the transfer sheet when the latter is separated from the transfer sheet bearing surface.
  • U.S. Patent Specification No. US-A-4063808 forms the basis for the preambles of claims 1 and 10. It discloses image forming apparatus in which discharge means cause discharge in a transfer sheet when the sheet is separated from transfer sheet bearing means.
  • an image forming apparatus is embodied as an electrophotographic color printer.
  • the electrophotographic color printer includes an image bearing member or drum-shaped OPC photosensitive member 1 rotated in a direction shown by the arrow.
  • a corona discharger 4 for charging the photosensitive member 1 with a predetermined polarity
  • a laser beam exposure means I for forming an electrostatic latent image on the photosensitive member 1
  • a plurality of developing devices 5 for developing the latent image formed on the photosensitive member 1 with toner having different colors (In the illustrated embodiment, four developing devices 5a, 5b, 5c and 5d are provided).
  • a visualized image or toner image formed on the photosensitive member 1 is rotated together with the photosensitive member 1 and is transferred onto a transfer sheet S (normally, transfer paper S) with the aid of a transferring device comprising a transfer roller 2 to which a bias voltage is applied. Then, the transfer paper S is treated so that the charges accummulated thereon by means of a corona discharger 3 is removed; thereafter, the transfer paper is separated from the transfer roller 2 by means of a separating claw 6, and is sent to a fixing device 8 by means of a conveying belt 7.
  • the corona discharger 3 also acts to remove the charges accummulated on the transfer roller 2.
  • the transfer roller 2 comprises an inner elastic layer 22 having a thickness of 5 mm formed on a cylinder 21 acting as a substrate and adapted to urge the transfer paper S against the photosensitive member 1, an intermediate conductive layer 23 (having a volume resistance of 1 x 108 ⁇ ⁇ cm or less) having a thickness of 10 »m and acting as an electrode for applying a transfer bias voltage, and an outer resistance layer 24 (having a volume resistance of 1 x 108 ⁇ ⁇ cm or more) having a thickness of 30 »m and adapted to maintain the charges on the surface of the transfer roller to hold the transfer paper S on the transfer roller.
  • an inner elastic layer 22 having a thickness of 5 mm formed on a cylinder 21 acting as a substrate and adapted to urge the transfer paper S against the photosensitive member 1
  • an intermediate conductive layer 23 having a thickness of 10 »m and acting as an electrode for applying a transfer bias voltage
  • an outer resistance layer 24 having a thickness of 30 »m and adapted to maintain the charges on the surface of the transfer roller to hold
  • the cylinder 21 was made of aluminium material
  • elastic layer 22 was made of urethane sponge material
  • conductive layer 23 was made of aluminium material
  • resistance layer 24 was made of PVdF (polyvinylidene fluoride) material having the volume resistance of 1013 - 1015 ⁇ ⁇ cm.
  • a peripheral length of the transfer roller 2 is so selected that, when a leading end of the transfer paper S wrapped around the transfer roller 2 reaches a transfer start position (an entrance of a nip formed between the photosensitive member 1 and the transfer roller 2), a trailing end of the transfer paper S is positioned out of an illumination area of the corona discharger 3 as will be described later.
  • the photosensitive member 1 having a negative charging polarity is charged with the negative polarity by means of the corona discharger 4, and a first electrostatic latent image is formed on the photosensitive member 1 by reducing the charging potential on the photosensitive member by the exposure by means of the laser beam exposure means I in response to image information. Then, for example by means of the developing device 5a, a potential-reduced portion of the first electrostatic latent image is reversely developed, thus forming a first toner image of a magenta color negatively charged, on the photosensitive member 1.
  • the transfer paper S is supplied at a predetermined timing, and a transfer bias voltage of 1.8 Kv having the polarity (for example, positive polarity) opposite to that of the the toner is applied to the conductive layer 23 of the transfer roller 2 immediately before the leading end of the transfer paper reaches the transfer start position, thus transferring the first toner image onto the transfer paper S and electrostatically absorbing the transfer paper S on the surface of the transfer roller 2.
  • a transfer bias voltage of 1.8 Kv having the polarity (for example, positive polarity) opposite to that of the the toner is applied to the conductive layer 23 of the transfer roller 2 immediately before the leading end of the transfer paper reaches the transfer start position, thus transferring the first toner image onto the transfer paper S and electrostatically absorbing the transfer paper S on the surface of the transfer roller 2.
  • a second electrostatic latent image is formed on the photosensitive member 1 by the laser beam exposure means I, and, thereafter, a second toner image having a color (for example, cyan) different from that of the first toner image and negatively charged is formed on the photosensitive member 1 by means of the developing device 5b.
  • the transfer roller 2 bearing the transfer paper S thereon is rotated in an endless fashion.
  • the second toner image is superimposed on the first toner image previously formed on the transfer paper S absorbed on and entrained by the transfer roller 2.
  • the bias voltage of + 2.1 Kv is applied to the transfer roller 2 immediately before the leading end of the transfer paper reaches the transfer start position.
  • third and fourth electrostatic latent images are formed on the photosensitive member 1 and are developed by the developing devices 5c and 5d, respectively; then, the third toner image (formed by yellow toner negatively charged) is superimposed on the second toner image formed on the transfer paper S and thereafter the fourth toner image (formed by black toner negatively charged) is superimposed on the third toner image, thus obtaining a four-color toner image on the transfer paper.
  • the transfer bias voltages of + 2.5 Kv and + 3.0 Kv are applied to the transfer roller 2, respectively, immediately before the leading end of the transfer paper reaches the transfer start position, respectively.
  • a main factor for reducing the transferring efficiency is the fact that, when the transfer paper S is separated from the photosensitive member 1 after the transferring operation has been completed, the surface of the transfer paper S is charged with a polarity opposite to that of the transfer bias voltage (the surface of the transfer roller bearing the transfer paper is also slightly charged) and the charged charges are accummulated during each transferring of the image, and, if the transfer bias voltage is constant, the transfer electric field will be reduced every transferring of the image.
  • a voltage obtained by overlapping the AC voltage with a DC bias voltage having the same polarity as and substantially the same value as the transfer bias voltage applied in the transferring of the fourth toner image is applied to the wire electrode 3a of the separating corona discharger 3.
  • the corona discharger 3 By applying the overlapped voltage to the wire electrode 3a, the corona discharger 3 generates an alternating electric field for the transfer paper, thus performing the positive discharge and the negative discharge alternatively.
  • the AC voltage is 5.5 Kv (effective value)
  • frequency is 500 Kz
  • DC bias voltage is + 3.0 Kv which is the same voltage as that applied to the transfer roller 2 in the transferring of the fourth color image.
  • a peripheral speed of the transfer roller 2 is 100 mm/sec; however, if the peripheral speed of the transfer roller 2 is in a range from 50 mm/sec to 200 mm/sec, the DC voltage will prefarably be 4 Kv - 7 Kv (effective value) and the frequency will preferably be 50 Hz - 800 Hz.
  • the reason why the voltage having the same polarity as that of the transfer bias voltage is applied to the corona discharger 3 is to remove the charges having the polarity opposite to that of the transfer bias voltage and charged on the surface of the transfer paper S bearing the toner image after the transferring of the toner image as mentioned above. By removing the charges from the surface of the transfer paper S, it is possible to prevent the scattering of the toner image on the transfer paper S when the transfer paper S is separated from the transfer roller 2.
  • the DC bias voltage applied to the wire electrode 3a of the corona discharger 3 has a value substantially the same as that of the transfer bias voltage, i.e., a value ranging from 80 % to 120 % of the transfer bias voltage immediately before the separation of the transfer paper from the transfer roller. That is to say, if the DC bais voltage is less than 80 % of the transfer bias voltage, the charges will not completely be removed from the surface of the transfer paper S, thus reducing the efficiency for preventing the scattering of the toner. Whereas, if the DC bias voltage is greater than 120 % of the transfer bias voltage, the surface of the transfer paper S will be charged with the same polarity as that of the transfer bias voltage, thus also reducing the efficiency for preventing the scattering of the toner.
  • the separating claw 6 is activated so that a free end of the claw contacts the surface of the transfer roller 2, whereby the transfer paper S is separated from the transfer roller 2.
  • the free end of the separating claw 6 is maintained to be contacted with the surface of the transfer roller 2 until the trailing end of the transfer paper S leaves the transfer roller 2, and, thereafter, is returned to an original retracted position.
  • the corona discharger 3 is activated from the time when the leading end of the transfer paper S reaches the transfer start position for the transferring of the last color toner image to the time when the trailing end of the transfer paper S leaves the transfer roller 2, thereby removing the charges (having the same polarity as that of the toner) accummulated on the transfer paper S and the charges (having the polarity opposite to that of the toner) created on the conductive layer of the transfer roller 2 due to such accummulated charges, with the result that the transfer paper S can be easily separated from the transfer roller by means of the separating claw 6 and the atmospheric discharge is reduced during the separating operation.
  • the transfer bias voltage being applied to the transfer roller 2 is turned OFF (i.e., turned to an earth potential).
  • the bias voltage being applied to the corona discharger 3 is also turned OFF, for preventing the occurrence of a problem described below.
  • the charging memory can easily be caused.
  • the reason why the bias voltage of the corona discharger 3 is turned OFF at the same time when the transfer bias voltage is turned OFF as mentioned above is to make the charge removing condition during the separation of the transfer paper S to equalize to the charge removing condition during the transferring of the last color toner image. That is to say, if the bias voltage of the corona discharger 3 is constant, when the transfer bias voltage is turned OFF, the transfer paper S is charged in the course of the separating and charge removing operation, which makes the prevention of the scattering of the toner impossible.
  • the transfer bias voltage may be changed to a predetermined small voltage, for example, + 1.0 Kv or less, which does not cause the above-mentioned ghost image.
  • the bias voltage applied to the corona discharger 3 is changed to be a voltage (having the same polarity as that of the predetermined voltage) substantially the same as that of the transfer bias voltage (for example, 80 % - 120 % of the transfer bias voltage).
  • the control of the bias voltage for the corona discharger 3 can be performed by controlling an exclusive DC power source connected to the AC power source.
  • the construction can be simplified by connecting the AC power source P1 to the transfer bias power source P2 in series and by sequence-controlling the ON/OFF control of the power sources or the voltage level control.
  • the transfer paper S is separated from the transfer roller 2, it is sent, by means of the conveying belt 7, to the thermal fixing device 8, where the toner images on the transfer paper S are fixed onto the transfer paper by fuzing and mixing the toner, thus forming four full-color image.
  • the full-color image obtained by the present invention was a sharp image without scattering the toner.
  • a corona discharger 3′ as shown in Fig. 5 can be used.
  • the corona discharger 3′ has grid electrodes acting as control electrodes for controlling the discharge of the corona discharger, which grid electrodes comprise a plurality of grid wires 3b arranged in a shield opening and spaced apart at a distance of 1 mm - 2 mm in the illustrated embodiment.
  • the first toner image having the predetermined color is formed on the photosensitive member 1, and the transfer bias voltage of 1.8 Kv having the polarity opposite to that of the toner is applied to the transfer roller 2 immediately before the leading end of the transfer paper supplied at a predetermined timing reaches the transfer start position, thus transferring the first toner image onto the transfer paper S and electrostatically absorbing the transfer paper S on the transfer roller 2.
  • the second image having the differenct color from that of the first toner image is formed on the photosensitive member 1, and this second toner image is superimposed on the first toner image previously formed on the transfer paper S.
  • the bias voltage of + 2.1 Kv is applied to the transfer roller 2 immediately before the leading end of the transfer paper S reaches the transfer start position, and at the same time, the DC voltage of + 5.5 Kv having the same polarity as that of the transfer bias voltage is applied to the discharge wire of the corona discharger 3′ and the bias voltage of + 2.52 Kv having the same polarity as that of the transfer bias voltage and being 120 % of the latter is applied to the grid wires 3b.
  • the DC voltage having the same polarity as that of the transfer bias voltage immediately before the separation of the transfer paper (+ 2.1 Kv) and substantially the same value as the latter, i.e., a valise of 80 % - 120 % of the transfer bias voltage may be applied to these grid wires 3b.
  • the separating claw 6 protrudes in a transfer paper moving path so that the free end of the claw contacts the surface of the transfer roller 2, whereby the transfer paper S is separated from the transfer roller.
  • the discharge of the corona discharger 3′ is continued until the trailing end of the transfer paper S leaves the surface of the transfer roller 2.
  • the images transferred onto the separated transfer paper is fixed by the fixing device 8, thus forming the two-color image.
  • the two-color image obtained by the illustrated embodiment of the present invention was a sharp image without scattering the toner.
  • the present invention can preferably be embodied as not only the multi-color or two-color image forming apparatus as mentioned above but also a mono-color image forming apparatus as will be described hereinafter.
  • the first toner image having the predetermined color is formed on the photosensitive member 1, and the transfer bias voltage of 1.8 Kv having the polarity opposite to that of the toner is applied to the transfer roller 2 immediately before the leading end of the transfer paper supplied at a predetermined timing reaches the transfer start position, thus transferring the first toner image onto the transfer paper S and electrostatically absorbing the transfer paper S on the transfer roller 2.
  • the DC voltage of + 5.5 Kv (frequency: 500 Kz) and the DC bias voltage of + 1.44 Kv (voltage of 80 % of the transfer bias voltage) are applied to the wire electrode 3a of the corona discharger 3.
  • the free end of the separating claw 6 contacts the surface of the transfer roller 2, thereby separating the transfer paper S from the transfer roller.
  • the corona discharger 3 is activated until the trailing end of the transfer paper S leaves the surface of the transfer roller 2.
  • the voltage applied to the wire electrode of the corona discharger 3 may have a value which is similar to that applied to the corona discharger 3 during the separation of the transfer paper onto which the four color images are transferred and which is substantially the same value as the transfer bias voltage (+ 1.8 Kv) with the same polarity as the latter, i.e., a value of 80 % - 120 % of the transfer bias voltage.
  • the toner image on the separated transfer paper S is fixed, thus forming the mono-color image. It was found that the mono-color image obtained by the illustrated embodiment was a sharp image without scattering the toner.
  • the AC voltage supplied by the AC power source is a voltage which periodically varies its voltage value from plus to minus or vice versa alternatively and includes a square wave voltage formed by periodically turning the DC power source ON and OFF.
  • the image forming apparatus can provide a good image without scattering the toner by effectively removing the charges from the transfer paper during the separation of the transfer paper from the transfer sheet bearing surface, and can provide the mono-color, two-color or multi-color image with high quality without generating the transferring unevenness.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Claims (10)

  1. Bilderzeugungsgerät mit
       einem lichtempfindlichen Bildträgerteil (1),
       einer Einrichtung (4, 5) zum Erzeugen eines Bildes auf dem Bildträgerteil,
       einer Übertragungsblatt-Trägervorrichtung (2) zum Transportieren eines Übertragungsblattes (S) in eine Überragungsposition zwischen dem Bildträgerteil (1) und der Übertragungsblatt-Trägervorrichtung (2), damit ein Bild auf das Übertragungsblatt übertragen wird, wobei die Übertragungsblatt-Trägervorrichtung (2) eine Oberflächenschicht (24) und eine innerhalb der Oberflächenschicht (24) angeordnete Leitschicht (23) aufweist,
       einer Vorrichtung (6) zum Ablösen des Übertragungsblattes von dem Übertragungsblatt-Trägerteil, nachdem ein Bild darauf übertragen worden ist,
       einer Spannungs-Anlegevorrichtung zum Anlegen einer ersten Spannung an die Leitschicht (23) bei einem Übertragungsvorgang und
       einer Entladevorrichtung (3) zum Verursachen der Entladung bei dem Übertragungsblatt (S), wenn das Übertragungsblatt (S) von der Übertragungsblatt-Trägervorrichtung (2) abgelöst wird, an die die Entladevorrichtung eine zweite Spannung mit derselben Polarität wie die der ersten Spannung durch die Spannungs-Anlegevorrichtung anlegt,
    dadurch gekennzeichnet, daß
       das Gerät eine Vielzahl von Bildübertragungsvorgängen auf dasselbe Übertragungsblatt durchführt und unabhängig von der Anzahl der auf das Übertragungsblatt übertragenen Bilder die zweite Spannung in dem Bereich zwischen 80 bis 120 % der ersten Spannung bei dem letzten Bildübertragungsvorgang liegt.
  2. Bilderzeugungsgerät nach Anspruch 1, dadurch gekennzeichnet, daß die Oberflächenschicht eine dielektrische Schicht aufweist.
  3. Bilderzeugungsgerät nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Entladevorrichtung eine Korona-Entladevorrichtung mit einer Drahtelektrode aufweist, an die die zweite Spannung angelegt wird.
  4. Bilderzeugungsgerät nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, daß die Entladevorrichtung abwechselnd eine positive Entladung und eine negative Entladung verursacht, wenn die zweite Spannung an die Entladevorrichtung angelegt wird.
  5. Bilderzeugungsgerät nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, daß die zweite Spannung mit derselben Polarität wie die der ersten Spannung und mit einem Wert gleich 80 bis 120 % der ersten Spannung eine Gleichspannung ist.
  6. Bilderzeugungsgerät nach Anspruch 5, gekennzeichnet durch eine Einrichtung zum Anlegen einer dritten Spannung, die eine Wechselspannung ist, die an die Entladevorrichtung angelegt wird, wenn das Übertragungsblatt von der Übertragungsblatt-Trägervorrichtung abgelöst wird.
  7. Bilderzeugungsgerät nach Anspruch 1, dadurch gekennzeichnet, daß die Entladevorrichtung eine Korona-Entladevorrichtung mit einer Drahtelektrode, an die eine Gleichspannung mit derselben Polarität wie die der ersten Spannung angelegt wird, und eine Steuerelektrode zum Steuern der Entladung der Entladevorrichtung aufweist, an die die zweite Spannung angelegt wird.
  8. Bilderzeugungsgerät nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, daß die Entladevorrichtung derart angeordnet ist, daß sich ein Hinterrand des Übertragungsblattes durch einen Entladebereich der Entladevorrichtung bewegt hat, wenn ein Vorderrand des Übertragungsblattes eine Übertragungs-Startposition erreicht, und daß die Entladevorrichtung eingeschaltet wird, wenn der Vorderrand des Übertragungsblattes eine Übertragungs-Abschlußposition unmittelbar vor der Ablösung des Übertragungsblattes von der Übertragungsblatt-Trägervorrichtung erreicht.
  9. Bilderzeugungsgerät nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, daß die erste Spannung ausgeschaltet wird, wenn der Hinterrand des Übertragungsblattes die Übertragungs-Abschlußposition erreicht, und daß die zu demselben Zeitpunkt die zweite Spannung, die an die Entladevorrichtung angelegt wird, auch ausgeschaltet wird.
  10. Bilderzeugungsverfahren mit
       einem Erzeugen (4, 5) eines Latentbildes auf einem lichtempfindlichen Bildträgerteil,
       einem Transportieren eines Übertragungsblattes (S) durch eine Übertragungsblatt-Trägervorrichtung (2) in eine Übertragungsposition zwischen dem Bildträgerteil und der Übertragungsblatt-Trägervorrichtung, damit ein Bild auf das Übertragungsblatt übertragen wird, wobei die Übertragungsblatt-Trägervorrichtung eine Oberflächenschicht (24) und eine Leitschicht (23) aufweist, die innerhalb der Oberflächenschicht angeordnet ist,
       einem Anlegen einer ersten Spannung an die Leitschicht (23) bei einem Übertragungsvorgang und
       einem Verursachen einer Entladung des Übertragungsblattes, wenn es von der Übertragungsblatt-Trägervorrichtung abgelöst wird, nachdem das Bild auf es übertragen worden ist, indem eine zweite Spannung mit derselben Polarität wie die der ersten Spannung angelegt wird,
    dadurch gekennzeichnet, daß
       eine Vielzahl von Übertragungsvorgängen auf ein einzelnes Übertragungsblatt ausgeführt werden und daß unabhängig von der Anzahl der auf das Übertragungsblatt übertragenen Bilder die zweite Spannung in dem Bereich zwischen 80 bis 120 % der ersten Spannung bei dem letzten Bildübertragungsvorgang liegt.
EP19910300343 1990-01-19 1991-01-17 Bilderzeugungsgerät mit Trägermitteln für ein Übertragungsblatt Expired - Lifetime EP0438303B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP960390A JPH03214182A (ja) 1990-01-19 1990-01-19 画像形成装置
JP9603/90 1990-01-19

Publications (3)

Publication Number Publication Date
EP0438303A2 EP0438303A2 (de) 1991-07-24
EP0438303A3 EP0438303A3 (en) 1992-05-06
EP0438303B1 true EP0438303B1 (de) 1995-06-14

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EP (1) EP0438303B1 (de)
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DE (1) DE69110306T2 (de)

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JP3256010B2 (ja) * 1992-12-22 2002-02-12 キヤノン株式会社 画像形成装置
EP0737901B1 (de) * 1995-04-14 2008-12-24 Sharp Kabushiki Kaisha Bilderzeugungsgerät

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Publication number Priority date Publication date Assignee Title
US3992557A (en) * 1974-07-17 1976-11-16 Canon Kabushiki Kaisha Image transfer method
US4027960A (en) * 1975-08-06 1977-06-07 Xerox Corporation Transfer system for electrostatic reproduction machine
US4063808A (en) * 1976-03-23 1977-12-20 International Business Machines Corporation Apparatus for neutralizing toner in a no charge exchange transfer
US4674860A (en) * 1984-08-21 1987-06-23 Konishiroku Photo Industry Co. Image transfer device

Also Published As

Publication number Publication date
JPH03214182A (ja) 1991-09-19
EP0438303A2 (de) 1991-07-24
DE69110306T2 (de) 1995-11-02
DE69110306D1 (de) 1995-07-20
EP0438303A3 (en) 1992-05-06

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