(19)
(11)EP 2 881 801 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
17.06.2020 Bulletin 2020/25

(21)Application number: 14185976.9

(22)Date of filing:  23.09.2014
(51)International Patent Classification (IPC): 
G03G 15/20(2006.01)

(54)

Image heating device

Bilderwärmungsvorrichtung

Dispositif de chauffage d'image


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 29.11.2013 JP 2013248454

(43)Date of publication of application:
10.06.2015 Bulletin 2015/24

(73)Proprietor: CANON KABUSHIKI KAISHA
Ohta-ku Tokyo 146-8501 (JP)

(72)Inventors:
  • Matsubara, Hideyuki
    Ohta-ku, Tokyo (JP)
  • Yonekubo, Hideaki
    Ohta-ku, Tokyo (JP)
  • Nakahara, Hisashi
    Ohta-ku, Tokyo (JP)
  • Kato, Akira
    Ohta-ku, Tokyo (JP)
  • Tanaka, Noriaki
    Ohta-ku, Tokyo (JP)
  • Shimura, Yasuhiro
    Ohta-ku, Tokyo (JP)
  • Fujiwara, Yuji
    Ohta-ku, Tokyo (JP)

(74)Representative: Williamson, Brian 
Canon Europe Limited European Patent Department 3 The Square Stockley Park
Uxbridge, Middlesex UB11 1ET
Uxbridge, Middlesex UB11 1ET (GB)


(56)References cited: : 
JP-A- 2003 317 898
US-A1- 2012 121 303
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    Field of the Invention



    [0001] The present invention relates to an image heating device to be preferably used as a fixing device provided in an image forming apparatus such as an electrophotographic copying machine and electrophotographic printer.

    Description of the Related Art



    [0002] In an image forming apparatus having an image heating device, when print processing is sequentially performed on a small-sized recording material of a width narrower than the width of a recording material of the maximum width usable in the apparatuses, the temperature of the non-sheet passing part of a fixing unit rises (i.e., non-sheet-passing part temperature rise occurs). In the technical field of film-heating fixing devices using a fixing film and a ceramic heater contacting the fixing film Japanese Patent Application Laid-Open No. 2003-317898 discloses a method for reducing the non-sheet-passing part temperature rise. In this method, a high thermal conductive member is held between a holding member for holding a heater and the heater to reduce unevenness in the temperature distribution of the heater.

    [0003] Meanwhile, in assembling the apparatus, if a position of the high thermal conductive member is misaligned to the heater, temperatures at end portions in a longitudinal direction of the heater may decrease and this may deteriorate the fixation properties, and/or the effects of reducing the temperature rise in the non-sheet-passing part by the high thermal conductive member may decrease. Especially, when a thin sheet is used as the high thermal conductive member, the handling of the sheet is difficult, and consequently, at the time of assembly, it is difficult to determine the position of the sheet to the heater. Relevant prior art documents are JP 2003 317898 and US 2012/121303.

    SUMMARY OF THE INVENTION



    [0004] The present invention is directed to an image heating device in which a high thermal conductive member can be easily positioned.

    [0005] According to a first aspect of the present invention, there is provided an image heating device as specified in claims 1 to 15.

    [0006] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0007] 

    Fig. 1 illustrates an image forming apparatus according to an exemplary embodiment of the present invention.

    Fig. 2A is a perspective view illustrating a fixing unit, and Fig. 2B is a cross-sectional view illustrating the fixing unit.

    Fig. 3A is a cross-sectional view illustrating the fixing unit, and Fig. 3B is a plan view illustrating a heater.

    Fig. 4 is a cross-sectional view illustrating a relationship among a heater, a high thermal conductive member, and a heater holding member according to a first exemplary embodiment.

    Figs. 5A and 5B are perspective views illustrating a relationship between the high thermal conductive member and the heater holding member.

    Fig. 6 illustrates a relationship of a thermal contact resistance between the heater and the high thermal conductive member with respect to a pressure.

    Fig. 7 illustrates a relationship between an excess amount of the high thermal conductive member and a reduction effect of an end portion temperature rise, and a relationship between the excess amount of the high thermal conductive member and a temperature decrease amount of the end portion.

    Fig. 8 is a cross-sectional view illustrating a relationship among a heater, a high thermal conductive member, and a heater holding member according to a second exemplary embodiment.

    Figs. 9A and 9B are perspective views illustrating a relationship between the high thermal conductive member and the heater holding member.

    Fig. 10 is a cross-sectional view illustrating a relationship among a heater, a high thermal conductive member, and a heater holding member according to a third exemplary embodiment.

    Figs. 11A and 11B are perspective views illustrating a relationship between the high thermal conductive member and the heater holding member.

    Fig. 12 is a cross-sectional view illustrating a modification of the image heating device.


    DESCRIPTION OF THE EMBODIMENTS



    [0008] Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. Each of the embodiments of the present invention described below can be implemented solely or as a combination of a plurality of the embodiments or features thereof where necessary or where the combination of elements or features from individual embodiments in a single embodiment is beneficial.

    [0009] Fig. 1 is a cross-sectional view illustrating a laser printer (image forming apparatus) 100 employing an electrophotographic recording technique. When a print signal is produced, a semiconductor laser 22 emits a laser beam modulated according to image information. The laser beam is deflected by a polygonal mirror 23, and exits from a scanner unit 21 via a reflecting mirror 24. With the laser beam, a photosensitive member 19 charged in a predetermined polarity by a charging roller 16 is scanned. This processing forms an electrostatic latent image on the photosensitive member 19. To the electrostatic latent image, toner is supplied from a development unit 17, and a toner image corresponding to the image information is formed on the photosensitive member 19. Meanwhile, recording paper (recording material) P stacked in a sheet cassette 11 is fed one by one by a pickup roller 12, and conveyed toward registration rollers 14 by rollers 13. The recording paper P is conveyed from the registration rollers 14 to a transfer position at the timing the toner image on the photosensitive member 19 arrives at the transfer position formed by the photosensitive member 19 and a transfer roller 20. While the recording paper P passes through the transfer position, the toner image on the photosensitive member 19 is transferred onto the recording paper P. Then, the recording paper P is heated by a fixing device (image heating device) 200 and the toner image is fixed by heating onto the recording paper P. The recording paper P bearing the fixed toner image is discharged by rollers 26 and 27 onto a tray provided at an upper part of the printer. A cleaner 18 is used to clean the photosensitive member 19. A motor 30 drives the fixing device 200 and other components. An image forming unit for forming an unfixed image onto the recording paper P includes the above-described photosensitive member 19, the charging roller 16, the scanner unit 21, the development unit 17, and the transfer roller 20. A cartridge 15 includes the charging roller 16, the development unit 17, the photosensitive member 19, and the cleaner 18. The cartridge 15 can be attached to or removed from the image forming apparatus body.

    [0010] The laser printer 100 according to the present exemplary embodiment can handle a plurality of sizes. More specifically, the laser printer 100 can perform printing on paper of a plurality of sizes including a letter-size paper (approximately 216 mm × 279 mm), an A4-size paper (210 mm × 297 mm), or an A5-size paper (148 mm × 210 mm) set in the sheet cassette 11. The laser printer 100 basically performs longitudinal paper feed (conveys paper such that the long sides of the paper are parallel to the conveyance direction), and the largest (widest) size in the usable standard recording material sizes (the usable paper sizes in a catalog) is a width of approximately 216 mm of the letter size paper. Papers (e.g., the A4-size paper and the A5-size paper) of narrower widths than the maximum size usable by the laser printer 100 is defined as small size paper.

    [0011] Fig. 2A is a perspective view illustrating the fixing unit (image heating device) 200, and Fig. 2B is a cross-sectional view illustrating the fixing unit viewed from the upstream side in the recording paper conveyance direction. Fig. 3A is a cross-sectional view illustrating the fixing unit. The line (reference) illustrated in Fig. 2B indicates a conveyance reference for recording paper. Recording paper is conveyed such that the center in the width direction of the recording paper is aligned with the line (reference). The arrow S in Figs. 2A and 3A indicates the conveyance direction of the recording paper.

    [0012] The fixing unit 200 includes a cylindrical film (moving member) 202, a heater (backup member) 300 that contacts the inner surface of the film 202, and a pressure roller (nip portion forming member) 208 that forms a fixing nip portion N with the heater 300 via the film 202. The base layer of the film 202 is formed of a heat-resistant resin such as polyimide or metal such as stainless steel. The pressure roller 208 includes a core bar (shaft) 209 formed of, for example, iron or aluminum, and an elastic layer 210 formed of, for example, a silicone rubber. The heater 300 is held by a heater holding member 201 formed of a heat-resistant resin. The heater holding member 201 has a guide function of guiding the rotation of the film 202. The heater holding member 201 is an elongated member for holding the heater in the longitudinal direction of the heater. The pressure roller 208 receives power from the motor 30 through a gear GY provided at an end portion of the shaft 209 and rotates in the direction indicated by the arrow. The rotation of the pressure roller 208 causes the film 202 to follow the rotation of the pressure roller 208 to rotate. A metallic stay 204 is used to apply pressure of a spring 7 to the heater holding member 201. The stay 204 also has a function to reinforce the heater holding member 201. The stay 204 is an elongated member provided in parallel with the heater holding member 201. At both ends of the stay 204, regulating members 112 for regulating the deviation movement of the film 202 to the generating line direction are provided. The force of the spring 7 is applied to the regulating members 112, the stay 204, the heater holding member 201, the heater 300, the film 202, and the pressure roller 208 in this order. A bearing 102 is provided to a frame 101 of the fixing unit 200. The bearing 102 rotatably holds the shaft 209 of the pressure roller 208. Consequently, between the pressure roller 208 and the heater holding member 201, through the stay 204, pressure for forming the fixing nip portion N is being applied. A connector 62 is used to supply electric power to the heater 300.

    [0013] The heater 300 includes a ceramic heater substrate 303, and resistance heating elements (heating elements) 301-1 and 301-2 provided on the heater substrate 303 along the substrate longitudinal direction. The heater 300 further includes an insulating surface protective layer 304 (in the present exemplary embodiment, the insulating surface protective layer 304 is formed of glass) that covers the resistance heating elements 301-1 and 301-2.

    [0014] Between the heater holding member 201 and the heater 300, a high thermal conductive member 220 is provided. The high thermal conductive member 220 has a higher thermal conductivity in the parallel direction to the plane of the high thermal conductive member 220 than the thermal conductivity of the heater substrate 303. For example, the high thermal conductive member 220 is a flexible sheet member using graphite. The opposite surface (rear surface) of the surface of the heater 300 facing the nip portion N contacts a thermistor (temperature detection element) 211 via the high thermal conductive member 220. The rear surface of the heater 300 also contacts, via the high thermal conductive member 220, a protective element 212 such as a thermoswitch and a temperature fuse that operates when temperature of the heater 300 abnormally rises to shut off the power supply to the heating elements 301-1 and 301-2. The thermistor 211 and the protective element 212 are pressed to the high thermal conductive member 220, for example, by a leaf spring (not illustrated). The recording paper P bearing an unfixed toner image is nipped and conveyed while being heated at the fixing nip portion N, and thereby the unfixed toner image is fixed. In the present exemplary embodiment, as the high thermal conductive member 220, a flexible sheet (tape) is used. More specifically, the Pyrolytic Graphite Sheet (PGS) (registered trademark) manufactured by Panasonic Corporation is used. The PGS has a thermal conductivity of 1000 W/mK in the direction parallel to the surface of the sheet, a thermal conductivity of 15 W/mK in the thickness direction, a thickness of 70 µm, and a density of 1.2 g/cm3.

    [0015] Fig. 3B is a plan view illustrating the heater 300. The resistance heating elements 301-1 and the 301-2 are electrically connected in series through a conductive element 305. To the resistance heating elements 301-1 and 301-2, electric power is supplied from an electrode portion C1 and an electrode portion C2 through the conductive element 305, respectively. A heating area is from an end portion D to an end portion E of the heating element. A heat generation distribution in the longitudinal direction of the resistance heating elements 301-1 and 301-2 of the heater 300 is set to ensure end portion fixation properties of recording paper such that amounts of generated heat at the end portions are higher than amount of generated heat at a central portion (i.e., as illustrated in Fig. 3B, the heating element width at the end portions is narrower than the heating element width at the central portion). Hereinafter, the narrow portions of the resistance heating elements 301-1 and 301-2 are referred to as end-narrowed portions. A length of a section DE, which is a heating area, is 222 mm, and the length is longer than the maximum size paper (letter size: 216 mm) set in the apparatus according to the present exemplary embodiment. Consequently, the end portions of the letter-size paper pass through around the center of the end-narrowed portions of the heating elements.

    [0016] As described above, the fixing device according to the present exemplary embodiment includes the film (moving member) 202 that moves while contacting the recording material at one surface, the heater (backup member) 300 that contacts the other surface of the moving member, and the holding member 201 for holding the backup member. The fixing device further includes the pressure roller (nip portion forming member) 208 that contacts one surface of the moving member and forms the nip portion with the backup member through the moving member, and the high thermal conductive member 220 that is held by the backup member and the holding member. Pressure is applied between the holding member 201 and the nip portion forming member 208, so that an image on the recording material is heated by the heat generated by the moving member while the recording material is nipped and conveyed with the nip portion N.

    [0017] With reference to Fig. 4 and Figs. 5A and 5B, a positional relationship among the heater holding member 201, the graphite sheet 220, and the heater 300 will be described. In the following description, description of one end portion will be made. However, description of the other end portion of the heater 300 is omitted since the other end portion has the same structure. The graphite sheet 220 is simply called as a sheet 220.

    [0018] Fig. 4 is a cross-sectional view of the area of the end portion in the longitudinal direction (X direction) of the heater holding member 201. Figs. 5A and 5B are perspective views of the area of the end portion in the longitudinal direction of the heater holding member 201. Fig. 5A illustrates only the heater holding member 201. Fig. 5B illustrates a state in which the sheet 220 is attached to the heater holding member 201. The heater 300 is disposed on the sheet 220 illustrated in Fig. 5B. The arrows view 1 in Fig. 3A, Fig. 4, and Fig. 5A indicate the same direction.

    [0019] To the heater holding member 201, a heater attachment groove recessed in the z direction is provided. The bottom surface of the heater attachment groove includes an attachment surface (holding surface) 201a and an attachment surface (second holding surface) 201b. On the attachment surface 201a, the heater 300 is provided via the sheet 220. On the attachment surface 201b, the heater 300 is directly provided. To the x direction end portion of the heater holding member 201, an arc shape butting portion 201c against which the end portion of the heater 300 butts is provided. The butting portion 201c regulates a position in the longitudinal direction (x direction) of the heater 300 in the attachment groove of the heater holding member 201. To the heater holding member 201, a back clearance portion (recessed portion) 201d that is further recessed in the z direction than the heater attachment surface 201a is provided. More specifically, at a part of the surface of the holding member 201 contacting the high thermal conductive member 220, the recessed portion is provided to prevent application of pressure to the high thermal conductive member 220, or to reduce the pressure applied to the high thermal conductive member 220 as compared to the attachment surface 201a. The recessed portion is provided, with respect to the direction (x direction) orthogonal to the conveyance direction (y direction) of the recording material, adjacent to an area (an area H described below) where the pressure is applied to the high thermal conductive member 220. The recessed portion is provided, with respect to the direction (x direction) orthogonal to the conveyance direction, outside of the area (section DE) where the heating elements are positioned.

    [0020] To the x direction end portion of the sheet 220, a portion 220a with a narrow width in the y direction is provided. The back clearance portion 201d has a hole 201e for passing the end portion 220a of the sheet 220 therethrough. The sheet 220 is provided such that the end portion 220a of the sheet 220 is passed through the hole 201e, thereby regulating the position of the sheet in the widthwise direction (y direction). Although a position of the sheet 220 in the x direction is regulated by the end portion 220b that is a border with the end portion 220a, the sheet 220 has a flexibility in the x direction since the hole 201e is wide in the x direction.

    [0021] In a step prior to the attachment of the heater 300 to the heater holding member 201, as described above, the sheet 220 is regulated with respect to the heater holding member 201, while the sheet 220 has a flexibility in the longitudinal direction (the state illustrated in Fig. 5B). Then, the heater 300 is disposed on the sheet 220, and further, pressure is applied by the spring 7 and thereby the sheet 220 closely contacts the attachment surface 201a as well as the heater 300. In the case where the sheet 220 is very thin like the graphite sheet used in the present exemplary embodiment, it is difficult to attach the sheet 220 such that the sheet 220 closely contacts the entire area of the attachment surface 201a at the step prior to the attachment of the heater 300. In the present exemplary embodiment, however, the heater 300 is attached to the heater holding member 201, and the sheet 220 is allowed to closely contact the heater 300 and the attachment surface 201a by further applying pressure. Consequently, the positional regulation of the sheet in the x direction at the step of the attachment of the sheet may be roughly made, and thus the step of attaching the sheet 220 in the assembly of the apparatus is simplified. At the step prior to the attachment of the heater 300, the close contact area of the sheet 220 and the heater holding member 201 in the x direction has not been determined. The heater 300 is attached and further, pressure is applied by the spring 7 to determine the close contact area of the sheet 220 and the heater holding member 201 to be the area (area H) to a line 201f, which is an end portion (also, an end portion of the recessed portion 201d) of the attachment surface 201a. In other words, the positional relationship between the sheet 220 and the heater holding member 201 in the x direction is determined.

    [0022] Next, a positional relationship between the sheet 220 and the heating area (the section DE in Fig. 3B) of the heater 300 will be described. A distance G from the heater butting portion 201c to the end portion line 201f of the attachment surface 201a of the heater holding member 201, and a distance F from the end portion to the heating area end portion of the heater 300 have been set to an approximately same distance (see Figs. 3A and 3B to Figs. 5A and 5B). Consequently, when the pressure is applied by the spring 7, the heating area (section DE) of the heater 300 in the x direction approximately corresponds to the area of the attachment surface 201a. In other words, the area H (, which corresponds to the area of the attachment surface 201a) where the sheet 220 is pressed by the spring 7, approximately corresponds to the heating area DE. As described above, when the delicate thin sheet is used, the heating area DE and the pressure area H of the sheet 220 can be accurately determined.

    [0023] The sheet 220 has the function to reduce overheating of the non-sheet passing area in the process of fixing small size paper. If the close contact area of the sheet 220 with respect to the heater in the x direction is too wide, temperatures at the end portions of the heater can be excessively decreased. Consequently, in the present exemplary embodiment, the pressure area H and the heating area DE are set to have the same area. However, it is not always necessary to set the pressure area H and the heating area DE to have the same area, and the positional relationship between the areas may be appropriately set. According to the present exemplary embodiment, the pressure area H can be easily changed only by changing the shape of the heater holding member 201.

    [0024] Fig. 6 illustrates a relationship between pressure applied to the heater and the high thermal conductive member (in the present exemplary embodiment, the graphite sheet) and thermal contact resistance (thermal resistance of contact areas). Black circles (●) in Fig. 6 indicate a relationship between thermal contact resistance and applied pressure in a case where grease is not used between the sheet 220 and the heater 300. They indicate that when the pressure is not applied by the spring 7 to the sheet 220 and the heater 300, even though the sheet 220 and the heater 300 are in contact with each other, the heat conduction is very low. In other words, to produce heat conduction between the sheet 220 and the heater 300, predetermined pressure is to be applied to the sheet 220 and the heater 300 in addition to the contact state. Although the sheet 220 is in contact with the heater 300 in the recessed portion 201d illustrated in Fig. 4, in this area, no pressure is applied between the heater 300 and the sheet 220, and there is little heat conduction from the heater 300 to the sheet 220. In other words, as in the heater holding member according to the present exemplary embodiment, by providing the recessed portion 201d, the border 201f between the area H where the function of the sheet is performed and the area G where the function of the sheet is not performed can be formed.

    [0025] White circles (o) in Fig. 6 indicates a relationship between thermal contact resistance and applied pressure in a case where MOLYKOTE (registered trademark) HP-300 GREASE (manufactured by Dow Corning Toray Co.,Ltd.) that is a fluorinated grease is applied between the sheet material 220 and the heater 300. They indicate that with the grease between the sheet 220 and the heater 300, the thermal contact resistance between the sheet 220 and the heater 300 can be reduced. Consequently, a thermal conductive material such as grease may be applied between the sheet 220 and the heater 300. As an alternative to the grease, for example, a high thermal conductive adhesive material may be used.

    [0026] Fig. 7 illustrates a reduction effect of the end portion temperature rise when small size paper is passed, and an amount of end portion temperature decrease in starting the fixing device by the use of the sheet 220. An excess amount of the sheet 220 indicates, with respect to the x direction, a length of the sheet pressure area exceeding the heating area DE. In a case where the sheet pressure area is wider than the heating area DE, the state is plus (+), and in a case where the sheet pressure area is narrower than the heating area DE, the state is minus (-) . Black circles (●) in Fig. 7 indicate a relationship between the reduction effect of the end portion temperature rise of the heater 300 and an excess amount of the sheet 220 in a case where A4-size paper, so-called small size paper, is passed. They indicate that when an excess amount becomes minus, the temperature rise reduction effect decreases greatly. As a result, when the small size paper is passed, due to the heater end portion temperature rise, the productivity decreases. Consequently, to reduce the heater end portion temperature rise and increase the productivity, the excess amount should not be too small.

    [0027] White circles (o) in Fig. 7 indicate a relationship between a temperature decrease amount of an end portion in starting the fixing device and an excess amount of the sheet 220. They indicate that when an excess amount is too large, the end portion temperature in starting the fixing device decreases. As a result, in the fixing processing of the first sheet performed immediately after the temperature of the fixing device has reached a fixing temperature, the fixation properties at the recording paper end portion decrease. Consequently, to ensure the fixation properties while reducing the temperature decrease of the end portion in starting the fixing device, the excess amount is to be reduced.

    [0028] In the present exemplary embodiment, the heating area DE of the heater 300 and the pressure area H of the sheet 220 are approximately the same, and consequently, both of the fixation properties at the recording paper end portion and the reduction in the non-sheet-passing part temperature rise by the sheet can be achieved. Further, in the present exemplary embodiment, the positional accuracy of the pressure area H is high, and consequently, the setting accuracy of the excess amount is also high.

    [0029] Hereinafter, a second exemplary embodiment of the present invention will be described with reference to Figs. 8, 9A, and 9B. In the present exemplary embodiment, to components described in the above-described first exemplary embodiment, the same reference numerals are applied. Descriptions about the components and functions similar to those in the first exemplary embodiment are omitted and only features in the present exemplary embodiment will be described. This similarly applies to the third exemplary embodiment and the subsequent exemplary embodiments.

    [0030] With reference to Figs. 8, 9A, and 9B, a positional relationship among the heater holding member 201, the sheet 220, and the heater 300 will be described. In the following description, description of one end portion will be made and the other end portion side has a similar structure. Fig. 8 is a cross-sectional view illustrating a longitudinal direction end portion area of the heater holding member 201. Figs. 9A and 9B are perspective views illustrating the longitudinal direction end portion area of the heater holding member 201. Fig. 9A illustrates only the heater holding member 201, and Fig. 9B illustrates a state in which the sheet 220 is attached to the heater holding member 201.

    [0031] To the heater holding member 201 according to the present exemplary embodiment, the back clearance portion (recessed portion) 201d that is recessed from the heater attachment surface 201a is provided. The back clearance portion 201d has a hole 201k for the installation of the sheet 220. An end portion of the sheet 220 has a long hole 220e. A stopper 500 is passed through the long hole 220e and the hole 201k to attach the sheet 220 to the heater holding member 201. The stopper 500 has a hook portion 500a, and after attaching to the heater holding member 201, the hook portion 500a is rotated by 180 degrees. This causes the stopper 500 to hook to the heater holding member 201, and the stopper 500 is prevented from coming out of the holding member 201. The sheet 220 is regulated by the long hole 220e in the widthwise direction (y direction). The longitudinal direction position of the sheet 220 has a certain degree of freedom since the stopper 500 holds the sheet 220 with a clearance. Since the stopper 500 does not come out of the holding member 201 with the hook portion 500a, in the assembly of the apparatus, the sheet 220 does not come out of the holding member 201.

    [0032] Hereinafter, a third exemplary embodiment of the present invention will be described with reference to Figs. 10, 11A, and 11B. To the heater holding member 201 according to the present exemplary embodiment, the back clearance portion (recessed portion) 201d that is recessed from the heater attachment surface 201a is provided. The back clearance portion 201d has a hole 201m for installing the sheet 220. An end portion of the sheet 220 has a long hole 220f. A stopper 501 is passed through the long hole 220f and the hole 201m to attach the sheet 220. The stopper 501 has a positioning portion 501a for positioning the sheet 220, a positioning portion 501b for positioning the stopper 501 itself to the heater holding member 201, and a hook portion 501c. The sheet 220 is regulated by the long hole 220f in the widthwise direction (y direction). The longitudinal direction position of the sheet 220 has a certain degree of freedom since the stopper 501 holds the sheet 220 with a space. Since the stopper 501 does not come out of the holding member 201 with the hook portion 501c, in the assembly of the apparatus, the sheet 220 does not come out of the holding member 201.

    [0033] In the above-described first to third exemplary embodiments, as the backup member, the heater 300 is used. The backup member may be a substrate (for example, a ceramic substrate) 600 without a heating element. To a structure in which the high thermal conductive member 220 is provided between the backup member 600 and the holding member 201, the holding structure for the sheet 220 according to one of the first to third exemplary embodiments may be applied. Fig. 12 illustrates an example of such structure. In this structure, a conductive layer is provided on the film 202 to generate heat in the electromagnetic induction heating. Further, the exemplary embodiments of the present invention can be applied to an apparatus having a structure in which a halogen heater is provided inside the tube of the film.

    [0034] In the first to third exemplary embodiments, as the moving member, the cylindrical film is used as an example. The exemplary embodiments of the present invention can be applied to an apparatus having a take-up film as the moving member, as an alternative to the cylindrical firm.

    [0035] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.


    Claims

    1. An image heating device comprising:

    a moving member (202) configured to move while an outer surface of the moving member (202) contacts a recording material (P);

    a heater (300) configured to contact an inner surface of the moving member (202);

    a holding member (201) configured to hold the heater (300);

    a nip portion forming member (208) configured to contact the outer surface of the moving member (202), so as to form a nip portion (N);

    a high thermal conductive member (220) held between the holding member (201) and the heater (300); and

    a pressure applying member (7) configured to apply a pressure to the nip portion(N),

    wherein, the recording material (P) on which an image has been formed is heated by heat received from the moving member (202) while being nipped and conveyed at the nip portion,

    characterized in that the holding member (201) includes a holding surface (201a) configured to hold the heater (300) via the high thermal conductive member (220), and a recessed portion (201d) provided adjacent to the holding surface (201a) in a direction orthogonal to a recording material conveyance direction (S), and configured so that no pressure is applied to the high thermal conductive member, or a reduced pressure is applied to the high thermal conductive member as compared to the holding surface (201a).


     
    2. The image heating device according to claim 1, wherein the high thermal conductive member (220) is longer than the holding surface (201a) in the orthogonal direction, and extends beyond the holding surface (201a).
     
    3. The image heating device according to claim 1 or 2, wherein the heater (300) includes a substrate(303) and a heating element (301-1, 301-2) formed on the substrate (303), and the recessed portion (201d) is provided in an area (G) outside of an area (H), in the orthogonal direction, in which the heating element (301-1, 301-2) is disposed.
     
    4. The image heating device according to any one of claims 1 to 3, wherein a length of the nip portion forming member (208) in the orthogonal direction is longer than the holding surface (201a), and the nip portion forming member (208) extends to the area (G) where the recessed portion (201d) of the holding member (201) is provided.
     
    5. The image heating device according to any one of claims 1 to 4, wherein the recessed portion (201d) has a hole (201e) arranged to pass the high thermal conductive member (220) there through.
     
    6. The image heating device according to any one of claims 1 to 5, wherein an end portion (220a) of the high thermal conductive member (220) in the orthogonal direction is narrower than a central portion of the high thermal conductive member (220).
     
    7. The image heating device according to any one of claims 1 to 6, further comprising a stopper (500) configured to prevent from the high thermal conductive member (220) coming off from the holding member (201) at the recessed portion (201d).
     
    8. The image heating device according to claim 7, wherein the stopper (500) is arranged to be fixed to the holding member (201) by inserting the stopper (500) into the holding member (201) and rotating the stopper (500).
     
    9. The image heating device according to claim 7, wherein the high thermal conductive member (220) has a hole (220f) arranged to pass the stopper (500) there through.
     
    10. The image heating device according to claim 9, wherein the hole (220f) is longer in the orthogonal direction.
     
    11. The image heating device according to any one of claims 1 to 10, wherein the holding member (201) has a second holding surface (201b) configured to hold the heater (300) directly and not via the high thermal conductive member (220), outside the recessed portion (201d) in the orthogonal direction.
     
    12. The image heating device according to any one of claims 1 to 11, wherein the high thermal conductive member (220) is flexible.
     
    13. The image heating device according to any one of claims 1 to 12, wherein the high thermal conductive member (220) is a graphite sheet.
     
    14. The image heating device according to any one of claims 1 to 13, wherein the moving member (202) is a cylindrical film.
     
    15. The image heating device according to claim 1, wherein the moving member (202) has a conductive layer that generates heat when power is supplied thereto.
     


    Ansprüche

    1. Bilderwärmungsvorrichtung, umfassend:

    ein bewegliches Element (202); das konfiguriert ist, sich zu bewegen, während eine Außenfläche des beweglichen Elements (202) in Kontakt mit einem Aufzeichnungsmaterial (P) ist;

    eine Heizeinrichtung (300), die konfiguriert ist, in Kontakt mit einer Innenfläche des beweglichen Elements (202) zu sein;

    ein Halteelement (201), das konfiguriert ist, die Heizeinrichtung (300) zu halten;

    ein Klemmabschnittbildungselement (208), das konfiguriert ist, mit der Außenfläche des beweglichen Elements (202) in Kontakt zu sein, um so einen Klemmabschnitt (N) zu bilden;

    ein hochwärmeleitendes Element (220), das zwischen dem Halteelement (201) und der Heizeinrichtung (300) gehalten wird; und

    ein Druckanwendungselement (7), das konfiguriert ist, einen Druck auf den Klemmabschnitt (N) auszuüben,

    wobei das Aufzeichnungsmaterial (P), auf welchem ein Bild erzeugt worden ist, durch vom beweglichen Element (202) empfangene Wärme erwärmt wird, während es gerade am Klemmabschnitt geklemmt und transportiert wird,

    dadurch gekennzeichnet, dass das Halteelement (201) beinhaltet: eine zum Halten der Heizeinrichtung (300) über das hochwärmeleitende Element (220) konfigurierte Haltefläche (201a) und einen vertieften Abschnitt (201d), der in einer zu einer Aufzeichnungsmaterialtransportrichtung (S) senkrechten Richtung benachbart zur Haltefläche (201a) vorgesehen und so konfiguriert ist, dass im Vergleich zur Haltefläche (201a) kein Druck auf das hochwärmeleitende Element oder ein reduzierter Druck auf das hochwärmeleitende Element ausgeübt wird.


     
    2. Bilderwärmungsvorrichtung nach Anspruch 1, wobei das hochwärmeleitende Element (220) in der senkrechten Richtung länger ist als die Haltefläche (201a) und sich über die Haltefläche (201a) hinaus erstreckt.
     
    3. Bilderwärmungsvorrichtung nach Anspruch 1 oder 2, wobei die Heizeinrichtung (300) ein Substrat (303) und ein auf dem Substrat (303) gebildetes Heizelement (301-1, 301-2) enthält und der vertiefte Abschnitt (201d) in der senkrechten Richtung in einem Gebiet (G) außerhalb eines Gebiets (H) vorgesehen ist, in welchem das Heizelement (301-1, 301-2) angeordnet ist.
     
    4. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 3, wobei eine Länge des Klemmabschnittbildungselements (208) in der senkrechten Richtung länger ist als die Haltefläche (201a) und wobei das Klemmabschnittbildungselement (208) sich bis zum Gebiet (G) erstreckt, in dem der vertiefte Abschnitt (201d) des Halteelements (201) vorgesehen ist.
     
    5. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 4, wobei der vertiefte Abschnitt (201d) ein Loch (201e) aufweist, welches dazu ausgelegt ist, das hochwärmeleitende Element (220) dort hindurchzuführen.
     
    6. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 5, wobei ein Endabschnitt (220a) des hochwärmeleitenden Elements (220) in der senkrechten Richtung schmaler ist als ein Mittelabschnitt des hochwärmeleitenden Elements (220).
     
    7. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 6, das weiterhin einen Stopper (500) umfasst, welcher konfiguriert ist, zu verhindern, dass das hochwärmeleitende Element (220) sich am vertieften Abschnitt (201d) vom Halteelement (201) löst.
     
    8. Bilderwärmungsvorrichtung nach Anspruch 7, wobei der Stopper (500) ausgelegt ist, am Halteelement (201) befestigt zu werden, indem der Stopper (500) in das Halteelement (201) eingeführt wird und der Stopper (500) gedreht wird.
     
    9. Bilderwärmungsvorrichtung nach Anspruch 7, wobei das hochwärmeleitende Element (220) ein Loch (220f) aufweist, das dazu ausgelegt ist, den Stopper (500) dort hindurchzuführen.
     
    10. Bilderwärmungsvorrichtung nach Anspruch 9, wobei das Loch (220f) in der senkrechten Richtung länger ist.
     
    11. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 10, wobei das Halteelement (201) außerhalb des vertieften Abschnitts (201d) in der senkrechten Richtung eine zweite Haltefläche (201b) aufweist, die konfiguriert ist, die Heizeinrichtung (300) direkt und nicht über das hochwärmeleitende Element (220) zu halten.
     
    12. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 11, wobei das hochwärmeleitende Element (220) flexibel ist.
     
    13. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 12, wobei das hochwärmeleitende Element (220) ein Graphitbogen ist.
     
    14. Bilderwärmungsvorrichtung nach einem der Ansprüche 1 bis 13, wobei das bewegliche Element (202) eine zylindrische Schicht ist.
     
    15. Bilderwärmungsvorrichtung nach Anspruch 1, wobei das bewegliche Element (202) eine leitende Schicht aufweist, die Wärme erzeugt, wenn ihr Strom zugeführt wird.
     


    Revendications

    1. Dispositif de chauffage d'image, comprenant :

    un élément mobile (202) configuré pour se déplacer tandis qu'une surface extérieure de l'élément mobile (202) contacte un matériau d'enregistrement (P) ;

    un réchauffeur (300) configuré pour contacter une surface intérieure de l'élément mobile (202) ;

    un élément de maintien (201) configuré pour maintenir le réchauffeur (300) ;

    un élément de formation de partie zone de pincement (208) configuré pour contacter la surface extérieure de l'élément mobile (202) de façon à former une partie zone de pincement (N) ;

    un élément hautement thermo-conducteur (220) maintenu entre l'élément de maintien (201) et le réchauffeur (300) ; et

    un élément d'application de pression (7) configuré pour appliquer une pression à la partie zone de pincement (N),

    dans lequel, le matériau d'enregistrement (P) sur lequel a été formée une image est chauffé par de la chaleur reçue de l'élément mobile (202) tandis qu'il est pincé et transporté au niveau de la partie zone de pincement,

    caractérisé en ce que l'élément de maintien (201) comprend une surface de maintien (201a) configurée pour maintenir le réchauffeur (300) par le biais de l'élément hautement thermo-conducteur (220), et une partie évidée (201d) disposée adjacente à la surface de maintien (201a) dans une direction orthogonale à un sens de transport de matériau d'enregistrement (S), et configurée de sorte qu'aucune pression ne soit appliquée à l'élément hautement thermo-conducteur, ou qu'une pression réduite soit appliquée à l'élément hautement thermo-conducteur par comparaison à la surface de maintien (201a).


     
    2. Dispositif de chauffage d'image selon la revendication 1, dans lequel l'élément hautement thermo-conducteur (220) est plus long que la surface de maintien (201a) dans la direction orthogonale, et s'étend au-delà de la surface de maintien (201a).
     
    3. Dispositif de chauffage d'image selon la revendication 1 ou 2, dans lequel le réchauffeur (300) comprend un substrat (303) et un élément chauffant (301-1, 301-2) formé sur le substrat (303), et la partie évidée (201d) est disposée dans une zone (G) à l'extérieur d'une zone (H), dans la direction orthogonale, dans laquelle est disposé l'élément chauffant (301-1, 301-2).
     
    4. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 3, dans lequel une longueur de l'élément de formation de partie zone de pincement (208) dans la direction orthogonale est plus longue que la surface de maintien (201a), et l'élément de formation de partie zone de pincement (208) s'étend jusqu'à la zone (G) dans laquelle est disposée la partie évidée (201d) de l'élément de maintien (201) .
     
    5. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 4, dans lequel la partie évidée (201d) comporte un trou (201e) conçu pour être traversé par l'élément hautement thermo-conducteur (220).
     
    6. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 5, dans lequel une partie d'extrémité (220a) de l'élément hautement thermo-conducteur (220) dans la direction orthogonale est plus étroite qu'une partie centrale de l'élément hautement thermo-conducteur (220) .
     
    7. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 6, comprenant en outre une butée (500) configurée pour empêcher que l'élément hautement thermo-conducteur (220) ne sorte de l'élément de maintien (201) au niveau de la partie évidée (201d).
     
    8. Dispositif de chauffage d'image selon la revendication 7, dans lequel la butée (500) est conçue pour être fixée à l'élément de maintien (201) par une introduction de la butée (500) dans l'élément de maintien (201) et par une rotation de la butée (500).
     
    9. Dispositif de chauffage d'image selon la revendication 7, dans lequel l'élément hautement thermo-conducteur (220) comporte un trou (220f) conçu pour être traversé par la butée (500).
     
    10. Dispositif de chauffage d'image selon la revendication 9, dans lequel le trou (220f) est plus long dans la direction orthogonale.
     
    11. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 10, dans lequel l'élément de maintien (201) comporte une seconde surface de maintien (201b) configurée pour maintenir le réchauffeur (300) directement et non pas par le biais de l'élément hautement thermo-conducteur (220), à l'extérieur de la partie évidée (201d) dans la direction orthogonale.
     
    12. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 11, dans lequel l'élément hautement thermo-conducteur (220) est flexible.
     
    13. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 12, dans lequel l'élément hautement thermo-conducteur (220) est une feuille de graphite.
     
    14. Dispositif de chauffage d'image selon l'une quelconque des revendications 1 à 13, dans lequel l'élément mobile (202) est un film cylindrique.
     
    15. Dispositif de chauffage d'image selon la revendication 1, dans lequel l'élément mobile (202) comporte une couche conductrice qui génère de la chaleur lorsque de l'énergie lui est fournie.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description