EP0369378A1 - Appareil de fixage d'images - Google Patents

Appareil de fixage d'images Download PDF

Info

Publication number
EP0369378A1
EP0369378A1 EP89121014A EP89121014A EP0369378A1 EP 0369378 A1 EP0369378 A1 EP 0369378A1 EP 89121014 A EP89121014 A EP 89121014A EP 89121014 A EP89121014 A EP 89121014A EP 0369378 A1 EP0369378 A1 EP 0369378A1
Authority
EP
European Patent Office
Prior art keywords
film
heater
image
supporting member
heat generating
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
EP89121014A
Other languages
German (de)
English (en)
Other versions
EP0369378B1 (fr
Inventor
Kensaku Kusaka
Hiromitsu Hirabayashi
Tamotsu Okada
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
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 JP63285542A external-priority patent/JPH07122770B2/ja
Priority claimed from JP63285543A external-priority patent/JPH07122771B2/ja
Priority claimed from JP16101888U external-priority patent/JPH073420Y2/ja
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0369378A1 publication Critical patent/EP0369378A1/fr
Application granted granted Critical
Publication of EP0369378B1 publication Critical patent/EP0369378B1/fr
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
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
    • 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
    • G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
    • G03G15/2014—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat
    • G03G15/2064—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat combined with pressure

Definitions

  • a reference PH1 is a sheet feed sensor (photosensor, for example) disposed in the sheet passage between the feeding roller 6 and the registration roller 9, and PH2 is a sheet discharge sensor (photosensor, for example) disposed next to the image fixing apparatus 20.
  • the take-up shaft 27 is driven in the clockwise detection as indicated by an arrow by an unshown driving system, by which the fixing film 23 travels from the supply shaft 24 side to the take-up shaft 27 side at the same speed as and in the same direction as the sheet P conveyed from the image forming station (transfer station 8) through the guide 10 to the fixing apparatus 20.
  • the pressing roller 22 is driven by an driving system in the counterclockwise direction as indicated by an arrow substantially at the same peripheral speed as the conveyance speed of the sheet P.
  • the heater 21 is made of a heat-resistive and electrically insulative material such as alumina or a material containing it, as a base material, and a heat generating layer 28 in the form of a line or stripe made of Ta2N or the like on the bottom surface of the base material, and a surface layer of Ta2O5 as a protection layer against sliding movement.
  • the bottom surface of the heater 21 is smooth, and the front and rear edge portion are rounded to permit smooth sliding movement of the fixing film 23.
  • the lever 25 is kept contacted and pressed by the backside of the sheet P until the sheet P completely passes by the lever position, and therefore, it is maintained at the lowered position, thus maintaining the on-state of the sensor 29.
  • the lever 25 position to be disengaged from the lever 25 the lever 25 becomes free to be projected again through the opening 10a.
  • the sensor 29 is rendered off, and the passage of the sheet P at the position of the sensor is informed to the control circuit.
  • An original G is placed on the original supporting platen 1, and the operator sets the number of image formations, the size of the sheet P used and the magnifications or the like, and thereafter, the operator depresses the image formation start key, upon which, the pick-up roller 6 feeds the sheet P from the cassette S, and the fed sheet is detected by a sensor PH1. Also, the image forming operation is started to the photosensitive drum 3 surface.
  • the top surface of the sheet carrying the unfixed toner image Ta introduced into the image fixing apparatus 20 is brought into close contact with the bottom surface of the fixing film 23 which is traveling at the same speed, and they are together passed through the nip between the heating member 21 and the pressing roller 22 without deviation or crease produced.
  • the toner fusing point used here means the minimum temperature required for fixing the toner and covers the case where the viscosity thereof decreases to such an extent as can be said to be fused, at the minimum fixable temperature and the case where the viscosity decreases to such an extent as can be said to be softened, at the minimum fixable temperature. Therefore, even when it is said that the toner is fused for convenience, it actually may mean the viscosity decrease to such an extent that it is actually softened. Similarly, when it is said that the toner is cooled and solidified for convenience, it actually may not be solidified depending on the materials of the toner, but can be said that the viscosity is sufficiently increased.
  • This conveying period is used as a cooling step to radiate the heat of the toner softened and fused during the heating period, so that the toner is cooled and fixed.
  • the cooling and solidification the coagulation force of the toner becomes significantly large so as to behave as a mass.
  • the adherence and bonding to the recording medium are increased, on the other hand, those to the fixing film decreases significantly. Since the heated, softened or fused toner during the heating process is pressed to the recording medium by the pressing member, and therefore, at least a part of the toner image is soaked into the surface layer of the recording medium, and the soaked and solidified portion provides an anchoring effect to increase the adherence and fixing force of the cooled and solidified toner to the recording medium.
  • the drive control may be carried out using the sheet leading edge and trailing edge detection signals by the sensor 29 and the lever 25.
  • the linear heat generation layer 28 of the heater 21 is instantaneously heated by energization up to a sufficiently high temperature beyond the toner fusing point (or the fixable temperature), and therefore, the preliminary heating of the heating member is not required, so that the heat transfer to the pressing roller 22 when the fixing operation is not carried out is small.
  • the fixing film, the toner image and the sheet are between the heater 21 and the pressing roller 22, and the temperature gradient is very steep because of the short heat generating period, and therefore, the pressing roller 22 is not easily heated so that the temperature of the pressing roller 22 is maintained below the toner fusing point even when practically required continuous image formation is performed.
  • the heat generating surface 28 is transferred mainly to the transfer material, so that in the heat generating region (A region) corresponding to the region P, no overheating occurs.
  • the heat quantity Q transfers mainly to the fixing film 23 and the pressing roller 22, and therefore, the heat generating surface corresponding to this region is not overheated.
  • the heat quantity Q mainly moves to the fixing film 23, and therefore, the region of the heat generating surface corresponding to this region is not overheated. Therefore, even if the thermal capacity of the heat generating surface 28 of the heater 21 is small, it is prevented from overheating over the entire region H. Therefore, the heat generating surface is protected from thermal damage due to the overheating, thus increasing the durability of the heater 21.
  • the pressing roller 22 is not directly contacted to the heater 21 but is urged through the fixing film 23. Therefore, the sliding contact, wearing and damage can be prevented in the portions of the heat generating surface 28 corresponding to the areas E and E where they are directly contacted ( Figure 6). By this, the durability of the heater is increased, and in addition, the rotational driving torque of the pressing roller 22 can be reduced because of the absence of the frictional resistance resulting from the direct contact portions E and E. This permits simplification of the driving system of the fixing apparatus.
  • H ⁇ F is satisfied also in this embodiment, so that the entire length H of the heat generating surface 28 of the heater 21 is press-contacted to the fixing film 23 by the pressing roller 22. Therefore, the heat transfer efficiency is good at any points of the entire heat generating surface region H. Thus, any portion of the heat generating surface is not overheated, so that the durability of the heater is enhanced.
  • a felt pad may be contacted to the surface of the film, and the pad is impregnated with silicone oil or the like to clean the film surface and to provide the film surface with the parting property.
  • the film may be electrically discharged using a grounded discharging brush.
  • the brush may be supplied with a bias voltage to charge the film within the range not disturbing the toner image.
  • electrification preventing agent may be applied or added.
  • the heat generating length relative to the maximum sheet passage width is selected so as to provide a margin of 12 mm in consideration of the lateral shift of the sheet, the oblique conveyance of the sheet and the temperature distribution of the heater.
  • the length of the pressing portion it is selected with a margin of 4 mm relative to the heat generating portion in consideration of the thrust play of the pressing portion and the accuracy of the parts.
  • the length of the protection layer is 246 mm.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fixing For Electrophotography (AREA)
EP89121014A 1988-11-11 1989-11-13 Appareil de fixage d'images Expired - Lifetime EP0369378B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP63285542A JPH07122770B2 (ja) 1988-11-11 1988-11-11 定着装置
JP285542/88 1988-11-11
JP285543/88 1988-11-11
JP63285543A JPH07122771B2 (ja) 1988-11-11 1988-11-11 定着装置
JP161018/88U 1988-12-12
JP16101888U JPH073420Y2 (ja) 1988-12-12 1988-12-12 定着装置

Publications (2)

Publication Number Publication Date
EP0369378A1 true EP0369378A1 (fr) 1990-05-23
EP0369378B1 EP0369378B1 (fr) 1994-09-28

Family

ID=27321776

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89121014A Expired - Lifetime EP0369378B1 (fr) 1988-11-11 1989-11-13 Appareil de fixage d'images

Country Status (2)

Country Link
EP (1) EP0369378B1 (fr)
DE (1) DE68918553T2 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0404112A2 (fr) * 1989-06-22 1990-12-27 Canon Kabushiki Kaisha Appareil de fixation d'images
EP0461595A2 (fr) * 1990-06-11 1991-12-18 Canon Kabushiki Kaisha Appareil de chauffage avec film sans fin
EP0461596A2 (fr) * 1990-06-11 1991-12-18 Canon Kabushiki Kaisha Appareil de chauffage avec film sans fin
US5293537A (en) * 1991-01-10 1994-03-08 Delphax Systems Image transport fusing system
EP1661836A1 (fr) * 2004-11-25 2006-05-31 Océ-Technologies B.V. Système de déchargement de feuilles

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3811828A (en) * 1970-10-29 1974-05-21 Ricoh Kk Process and device for heating and fixing an image upon a recording medium
US3948215A (en) * 1972-03-14 1976-04-06 Ricoh Co., Ltd. Fixing toner images in electrophotography
EP0295901A2 (fr) * 1987-06-16 1988-12-21 Canon Kabushiki Kaisha Appareil de fixage d'images

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3811828A (en) * 1970-10-29 1974-05-21 Ricoh Kk Process and device for heating and fixing an image upon a recording medium
US3948215A (en) * 1972-03-14 1976-04-06 Ricoh Co., Ltd. Fixing toner images in electrophotography
EP0295901A2 (fr) * 1987-06-16 1988-12-21 Canon Kabushiki Kaisha Appareil de fixage d'images

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0404112A2 (fr) * 1989-06-22 1990-12-27 Canon Kabushiki Kaisha Appareil de fixation d'images
EP0404112A3 (fr) * 1989-06-22 1991-06-26 Canon Kabushiki Kaisha Appareil de fixation d'images
EP0461595A2 (fr) * 1990-06-11 1991-12-18 Canon Kabushiki Kaisha Appareil de chauffage avec film sans fin
EP0461596A2 (fr) * 1990-06-11 1991-12-18 Canon Kabushiki Kaisha Appareil de chauffage avec film sans fin
EP0461595A3 (en) * 1990-06-11 1993-09-29 Canon Kabushiki Kaisha Heating apparatus using endless film
EP0461596A3 (fr) * 1990-06-11 1994-02-09 Canon Kk
US5525775A (en) * 1990-06-11 1996-06-11 Canon Kabushiki Kaisha Heating apparatus using endless film
US5293537A (en) * 1991-01-10 1994-03-08 Delphax Systems Image transport fusing system
EP1661836A1 (fr) * 2004-11-25 2006-05-31 Océ-Technologies B.V. Système de déchargement de feuilles

Also Published As

Publication number Publication date
DE68918553T2 (de) 1995-02-16
EP0369378B1 (fr) 1994-09-28
DE68918553D1 (de) 1994-11-03

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