EP0096450B1 - Elektrophotographisches Kopiergerät - Google Patents

Elektrophotographisches Kopiergerät Download PDF

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Publication number
EP0096450B1
EP0096450B1 EP83200851A EP83200851A EP0096450B1 EP 0096450 B1 EP0096450 B1 EP 0096450B1 EP 83200851 A EP83200851 A EP 83200851A EP 83200851 A EP83200851 A EP 83200851A EP 0096450 B1 EP0096450 B1 EP 0096450B1
Authority
EP
European Patent Office
Prior art keywords
roller
rollers
copier
rough surface
opposing
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
Application number
EP83200851A
Other languages
English (en)
French (fr)
Other versions
EP0096450A1 (de
Inventor
Bruno Borgata Paradiso Cestari
Riccardo Forlani
Piero Gontero
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.)
Telecom Italia SpA
Original Assignee
Ing C Olivetti and C SpA
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 IT67250/81A external-priority patent/IT1144107B/it
Application filed by Ing C Olivetti and C SpA filed Critical Ing C Olivetti and C SpA
Priority to AT83200851T priority Critical patent/ATE20158T1/de
Publication of EP0096450A1 publication Critical patent/EP0096450A1/de
Application granted granted Critical
Publication of EP0096450B1 publication Critical patent/EP0096450B1/de
Expired 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
    • G03G15/80—Details relating to power supplies, circuits boards, electrical connections
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
    • G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration
    • G03G15/0928—Details concerning the magnetic brush roller structure, e.g. magnet configuration relating to the shell, e.g. structure, composition
    • 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
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G03G15/2092—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using pressure only

Definitions

  • This invention relates to an electrophotographic copier comprising means for developing a latent image of an original to be reproduced and formed on a photoconductor element, means for transferring the developed image on to a sheet of paper, and a pair of opposing rollers for the cold-fixing of the image transferred on to the paper sheet, by the action of the pressure between the rollers, and in which the rollers have their axes inclined to each other and at least one roller has a rough surface.
  • rollers pressed one against the other which have their axes inclined at a small angle to each other in order to compensate for the axial deformation due to the applied load.
  • a fixing device is described as formed of a pair of rollers, at least one of which has a surface roughened to produce a mat surface of fine texture.
  • this roller has its axis inclined with respect to that of the other roller. The inclination of the axes leads to deformation of the copying sheets by twisting.
  • the object of the invention is to provide a copier which obviates this drawback.
  • the invention is characterised in the manner set forth in claim 1 below.
  • EP-80 902 199 which corresponds to WO-81/01060, discloses a-pair of rollers one of which is compliant.
  • a carriage 12 is mounted on the top of copier casing 10 and can move in the two directions 14, to convey an original 16 disposed on a transparent plate 18 fixed to the carriage 12.
  • the original 16 is illuminated by a lamp 20 in order to reflect the image to be reproduced along an optical path 22 onto a photoconductor 24 wrapped round a rotatable drum 26.
  • the drum 26 rotates in a clockwise direction in order to move the photoconductor 24 successively into an electrostatic charge station 28 fed by a negative voltage of the order of -7000 V, into an exposure zone 30, into a development zone 32, into a transfer station 34 fed by a negative voltage of about -7300 V, and into an erasure station 36 fed by an insulating voltage of about 3500 Vac.
  • the residual toner remaining on the photoconductor 24 is removed in the station 32.
  • a drawer 38 containing copying sheets 39 is removably fitted into an aperture 40 situated in the left hand side 41 of the copier.
  • the sheets 39 are fed one at a time by a sheet feeding roller 42 which feeds them by way of rollers 44, 46 to the transfer station 34.
  • the sheets 39 are then conveyed by a belt conveyor 50 to a cold fixing station 54 constituted by two pressure rollers 56, 58.
  • the sheets are fed from the fixing station 54 through an aperture 43 to a tray 49 fixed to the left hand side 41 of the copying machine.
  • the development station 32 comprises a magnetic brush 100 formed from a rotatable sleeve 102 of non-magnetic material such as stainless steel, on which there is formed a uniform layer 103 of toner fed by a hopper 104. Inside the sleeve 102 there can rotate a steel shaft on which permanent magnets 108 are fixed so that they extend axially and project radially from the shaft 106 nearly to the inside surface of the sleeve 102. The shaft 106 is rotated in a clockwise direction in Fig. 1 while the sleeve 102 rotates in an-anticiockwise direction with a peripheral speed between about 600 and 750 mm/sec.
  • the toner Under the effect of the rotation of the magnetic field of the magnets 108, the toner becomes disposed on the sleeve 102 in the form of a layer 103 of uniform thickness, and slides on the sleeve in an anticlockwise direction with a peripheral speed greater than that of the sleeve 102, namely about 800 mm/sec.
  • the toner layer 103 grazes the photoconductor 24 in the zone 154 of minimum distance between the sleeve 102 and drum 26, in order to develop in the normal manner the latent image formed on the photoconductor 24.
  • the fixing rollers 56, 58 are rotatable on two pairs of levers 72, 74 respectively, of which only one pair is shown in the Figure, and are pressed together by spring means 71 acting on one end 73 of the levers 72, 74, which are hinged at their other end on a pin 75.
  • the springs 71 apply to the levers 72, 74 a load which is so determined that the pressure exerted by the upper roller 58'on the lower 56 is sufficient to fix a toner image deposited on the copying sheet 39 when the copying sheet is made to pass between the two rollers.
  • the rollers 56, 58 are rotated in opposite directions at the same angular speed by means of a pair of equal gear wheels 157, 159.
  • the lower roller 56 is of hardened steel and has a specularly polished rolling surface 56', the upper roller 58 also being of hardened steel but having its surface 58' sandblasted and chromium plates by a procedure known in the art in order to provide copies having a non-reflecting opaque surface.
  • the two rollers 56, 58 are also so mounted that their axes form a small contained angle of between 30' and 2° in order to compensate for axial deformation due to the high applied load, and to allow uniform distribution of the load along the contact line.
  • the upper roller 58 can be constructed with a diameter slightly greater than the diameter of the lower roller so as to create a limited peripheral slippage of the upper roller 58 relative to the lower roller 56. In this manner, the upper fibres of the sheet 39 are stretched to an equal extent over the entire width of the sheet, so that any twist caused by the inclination of the rollers is nullified.
  • peripheral slippage S is defined by the equation:
  • cp is the difference between the diameters of the two rollers and ⁇ 1> 1 is the diameter of the lower roller 56.
  • the lower roller 56 ( Figures 2 and 3) is lubricated with a small quantity of silicone oil, which is transferred by contact to the upper roller 58 during their rotation, during these stages which precede the arrival of a copying sheet to be fixed.
  • the purpose of lubricating the fixing roller 58 is as known, to prevent adhesion between it and the toner particles, which would soil the copying sheets during their fixing during the subsequent revolutions of the roller 58.
  • the roller 56 is lubricated by means of a strip of felt 160 ( Figure 3) on which is wound a heavy fabric 162, for example a pile fabric provided on one face with a dense layer of fibres 168 such as velvet, so as to form a substantially cylindrical element 160, 162 removably inserted into an appropriate seat 164 supported by a cross member 165 and having a slot 166 facing the roller 56 over its entire length.
  • the portion 167 of velvet fabric 162 included in the slot 166 extends outwardly such that its hairs 168 touch the roller 56.
  • the felt 160 is soaked with a predetermined quantity of silicone oil, which is then transferred to the roller 56 by capillarity through the fabric 182 by means of the fibres 168 of the velvet 162.
  • the quantity of oil transferred from the lubricating element 160 to the roller 56 can be varied by choosing different lengths of hairs 168. From tests carried out, it has been found that by varying the pile length from about 3 mm to about 6 mm, a corresponding average oil consumption is obtained which varies from about 4 g to about 7 g for every 10,000 copies made.
  • the oil is transferred to the cylinder 56 in a constant manner over the entire length of the roller without any precise positioning of the element 160 relative to the roller 56 being required.
  • a pile fabric of the velvet type rather than other lubricating elements formed either from felt alone or from felt enclosed in a non-pile fabric, there is no oil accumulation at the contact strip between the element 160 and roller 56 during the non-working periods of the machine.
  • the machine is supplied electrically by means of a power unit disposed on a single printed circuit board 80 ( Figure 1) comprising all the supply circuits of the voltages required for the copier operation. More specifically, the board 80 is disposed vertically, and comprises a stabilised low voltage D.C. supply circuit 81 of known type, and not described in detail. The board 80 also comprises the high voltage generating circuits used in the charge station 28, transfer station 34 and erasure station 36. A set-up transformer 82 with a step-up ratio of 1:100 is fed with an alternating voltage of the order of 24 Vac taken from the power unit 81 at two tracks 83.
  • the transformer 82 is embedded in a block 84 of epoxy resin of the type suitable for high voltage and having a dielectric constant of not less than 15,000 V/mm, and a specific electrical volume resistivity of the order of 1.1014 ohm.cm.
  • the transformer 82 is of the known type, and is suitable for the high voltages concerned.
  • Two tracks 85 emerge from the transformer 82 to supply a voltage quadrupler circuit 86 of known type formed from a network of diodes and capacitors and embedded in an epoxy resin block 87 of the same type as stated heretofore:
  • the high voltages required by the copier are available at two terminals 88, 89 fixed directly to the resin block 87, a third terminal 90 representing the earth of the high voltage power unit.
  • An alternating voltage of about 3,500 Vac for supplying the erasure station 36 is taken from a terminal 91 directly fixed to the block 84.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fixing For Electrophotography (AREA)

Claims (5)

1. Elektrophotographisches Kopiergerät mit einer Einrichtung (32) zum Entwickeln .eines latenten Bildes von einem zu reproduzierenden und auf einem Photoleitungselement (24, 26) abgebildeten Originals, einer Vorrichtung (34), die das entwickelte Bild auf ein Blatt Papier (39) überträgt, und einem Paar sich gegenüberliegender, nicht nachgiebiger Rollen (56, 58) zur Kaltfixierung des auf das Blatt Papier übertragenen Bildes durch die Wirkung des Druckes zwischen den Rollen, wobei die Rollen zueinander geneigte Achsen aufweisen und zumindest eine Rolle eine rauhe Oberfläche aufweist, dadurch gekennzeichnet, daß die Rolle (58) mit der rauhen Oberflächen eine größere Umfangsgeschwindigkeit als die gegenüberliegende Rolle (56) des Paares aufweist, so daß jede durch die Neigung der Rollen hervorgerufene Deformation des Blattes vollständig vermieden ist.
2. Kopiergerät nach Anspruch 1, dadurch gekennzeichnet, daß die Rollen (56, 58) mit der gleichen Winkelgeschwindigkeit in umgekehrte Richtungen rotieren und die Rolle (58) mit der rauhen Oberfläche einen größeren Durchmesser als die gegenüberliegende Rolle (56) aufweist.
3. Kopiergerät nach Anspruch 2, dadurch gekennzeichnet, daß die Rolle (58) mit der rauhen Oberfläche über die gegenüberliegende Rolle (56) mit einem Schlupfverhältnis von S=ΔΦ/Φ zwischen 0,001 und 0,003 gleitet, wobei ΔΦ den Unterschied der Durchmesser angibt und 0 den Durchmesser der gegenüberliegenden Rolle.
4. Kopiergerät nach jedem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die gegenüberliegende Rolle (56) mittels eines Schmierelements mit Siliconöl geschmiert wird, wobei das Schmierelement aus einem schwammartigen Körper (160) gebildet ist, der von einem auf seiner Außenfläche mit Florfasern (168) versehenen Gewebe (162) eingeschlossen ist, so daß das Öl durch Kontakt auf die Rolle (58) mit der auhen Oberfläche übertragen wird, um das Auhaften von Farblackpartikeln auf deren Oberfläche zu verhindern.
5. Kopiergerät nach Anspruch 4, dadurch gekennzeichnet, daß das Gewebe (162) ein Velour mit einer Schicht von Florfasern, deren Länge zwischen 1 mm bis zu 10 mm liegt, ist.
EP83200851A 1981-02-24 1982-02-10 Elektrophotographisches Kopiergerät Expired EP0096450B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83200851T ATE20158T1 (de) 1981-02-24 1982-02-10 Elektrophotographisches kopiergeraet.

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT6725081 1981-02-24
IT67250/81A IT1144107B (it) 1981-02-24 1981-02-24 Copiatrice elettrofotografica
EP82300666A EP0060030A3 (de) 1981-02-24 1982-02-10 Elektrofotografische Kopiereinrichtung

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
EP82300666A Division EP0060030A3 (de) 1981-02-24 1982-02-10 Elektrofotografische Kopiereinrichtung
EP82300666A Division-Into EP0060030A3 (de) 1981-02-24 1982-02-10 Elektrofotografische Kopiereinrichtung

Publications (2)

Publication Number Publication Date
EP0096450A1 EP0096450A1 (de) 1983-12-21
EP0096450B1 true EP0096450B1 (de) 1986-05-28

Family

ID=26085051

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83200851A Expired EP0096450B1 (de) 1981-02-24 1982-02-10 Elektrophotographisches Kopiergerät

Country Status (2)

Country Link
EP (1) EP0096450B1 (de)
DE (1) DE3271486D1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6474572A (en) * 1987-09-16 1989-03-20 Fuji Xerox Co Ltd Roller driving device in fixing device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0039361A1 (de) * 1979-10-15 1981-11-11 Minnesota Mining & Mfg Schmelz-druckzylinder mit niedrigem glanz.

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3846151A (en) * 1972-09-05 1974-11-05 Addressograph Multigraph Fixing device
JPS5492747A (en) * 1977-12-29 1979-07-23 Minolta Camera Co Ltd Pressure fixing device of powder lmages

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0039361A1 (de) * 1979-10-15 1981-11-11 Minnesota Mining & Mfg Schmelz-druckzylinder mit niedrigem glanz.

Also Published As

Publication number Publication date
DE3271486D1 (en) 1986-07-03
EP0096450A1 (de) 1983-12-21

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