Patent Publication Number: US-11022917-B2

Title: Image heating apparatus

Description:
BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to an image heating apparatus as a fixing unit for heating and fixing an unfixed toner image formed and borne on a recording material in an image forming apparatus such as a copying machine and a printer using an electrophotographic method or an electrostatic recording method. 
     Description of the Related Art 
     Conventionally, the heat roller method has been widely used in, for example, image heating apparatuses. The heat roller method heats a recording material as a heating target material while sandwiching and conveying it at a nip portion formed by a heat roller as a heating member kept at a predetermined temperature and a pressing roller as a pressing member in pressure contact with the heat roller. 
     Further, besides the heat roller method, an image heating apparatus based on the film heating method has been contrived (for example, Japanese Patent Application Laid-Open No. 4-44075). The image heating apparatus based on the film heating method includes a heater that serves as a heat source, a support member (a stay) for the heater, an endless thermally-resistant film (hereinafter referred to as a film) that faces and contacts the heater, and a pressing roller that brings a recording material into close contact with the heater via the film. The image heating apparatus based on the film heating method heats and fixes an unfixed image formed and borne on a surface of the recording material onto the surface of the recording material by applying heat of the heater to the recording material via the film at the nip portion formed by the heater and the pressing roller. 
     A heater having a low thermal capacity can be used as the heater for such an image heating apparatus based on the film heating method. Therefore, this type of image heating apparatus can achieve power saving and a reduction in a waiting time (a reduction in a first printout time) compared to the apparatuses based on the heat roller method or the like. 
     Further, for the image heating apparatus, consideration has been given to preventing a reduction in durability of the fixing film to prevent occurrence of a defect (Japanese Patent No. 5882956). In this configuration, the image heating apparatus is configured in such a manner that a holding member holding the fixing film at an end portion is provided movably in an upstream direction of a recording material conveyance direction, and the holding member moves upstream to push an inner peripheral surface of the fixing film in the upstream direction. In this manner, there has been discussed the image heating apparatus configured to correct the orientation of the fixing film to reduce a force for displacement, thereby allowing the fixing film to operate in the corrected orientation and under the reduced force for displacement and thus being able to improve the reduction in the durability of the fixing film. 
     However, according to the image heating apparatus configured to allow the holding member to move in the upstream direction of the recording material conveyance direction, the holding member pushes the inner peripheral surface of the fixing film to change the orientation of the fixing film. This results in an increase in a pressure with which the holding member pushes the fixing film at a portion where the holding member pushes the inner peripheral surface of the fixing film, thereby leading to an increase in sliding friction between the holding member and the fixing film and thus an increase in wear of the inner peripheral surface of the fixing film at the abutment portion. 
     Especially, when a lubricant applied on the nip portion of the image heating apparatus is deteriorated due to endurance or the amount of the lubricant reduces in the course of endurance due to volatilization, the lubricant interposed at the abutment portion between the inner peripheral surface of the fixing film and the holding member also reduces due to the endurance, so that the wear in the course of the endurance increases. 
     Furthermore, the image heating apparatus may be continuously used even after having ended its nominal lifetime, and, in this case, the increase in the wear leads to a reduction in the thickness of a base layer of the fixing film and thus a reduction in the strength of the fixing film at the abutment portion, thereby raising a risk of a breakage of the fixing film such as a rupture and buckling. 
     Increasing the thickness of the base layer of the fixing film in an initial state in advance may be one conceivable method for preventing the reduction in the thickness of the base layer of the fixing film and thus the reduction in the strength due to scraped inner peripheral surface of the base layer of the fixing film, but brings in such a problem that a time required to start up the image heating apparatus is lengthened because of an increase in the thermal capacity of the base layer. 
     Also, another possible risk is impairment of the slidability at the nip portion due to contamination of the lubricant in the fixing film or at the nip portion with shaved powder, followed by occurrence of a slip of the fixing film, an image streak, or the like. 
     SUMMARY OF THE DISCLOSURE 
     In consideration of these circumstances, the present disclosure provides, as an image heating apparatus configured to restrict a displacement of a fixing member, an image heating apparatus that reduces wear on an inner peripheral surface of the fixing member and thus reduce a defect such as a slip and an image streak due to shaved powder. 
     According to an aspect of the present disclosure, an image heating apparatus is configured to allow a recording material with an image formed thereon to be heated while being conveyed at a nip portion, thereby allowing the image to be fixed onto the recording material. The image heating apparatus includes an endless film, a pressing member forming the nip portion together with the film by contacting an outer peripheral surface of the film, and a film holding member provided at a longitudinal end portion of the film. The film holding member includes a movable member. The movable member includes a restriction surface configured to restrict a longitudinal movement of the film by contacting the film when the film moves longitudinally and a guide surface facing an inner peripheral surface of the film and configured to guide a rotation of the film. In addition, the film holding member further includes a biased member supporting the movable member and including a force reception portion configured to receive a biasing force toward the pressing member. The guide surface of the movable member includes a lubricant application unit. The film holding member is configured in such a manner that a longitudinal movement of the movable member causes the movable member to move upstream in a conveyance direction of the recording material at the nip portion relative to the biased member and causes the lubricant application unit to abut against the inner peripheral surface of the fixing film. 
     Further features and aspects of the present disclosure will become apparent from the following description of example embodiments, features and aspects thereof with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of an image forming apparatus according to a first example embodiment. 
         FIG. 2  is a cross-sectional view of an image heating apparatus that is an example according to the first example embodiment. 
         FIG. 3  is a cross-sectional view of the image heating apparatus according to the first example embodiment. 
         FIG. 4  is an exploded perspective view of the image heating apparatus according to the first example embodiment. 
         FIGS. 5A and 5B  are perspective views of a movable member and a biased member forming a flange according to the first example embodiment, respectively. 
         FIGS. 6A and 6B  are cross-sectional views illustrating a vicinity of the flange in the image heating apparatus according to the first example embodiment. 
         FIG. 7  is a cross-sectional view illustrating a vicinity of the flange in the image heating apparatus according to an example modification of the first example embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following description, how the present disclosure can be implemented will be described in detail based on an example embodiment thereof with reference to the drawings. However, dimensions, materials, shapes, a relative layout, and the like of components that will be described in the following example embodiment shall be changed as appropriate according to a configuration of an apparatus to which the present disclosure is applied and various kinds of conditions. In other words, they are not intended to limit the scope of the present disclosure to the following example embodiment. 
     (1) Example Image Forming Apparatus 
     First of all, a configuration of an image forming apparatus  100  according to a first example embodiment will be described with reference to  FIG. 1 .  FIG. 1  is a schematic cross-sectional view of the image forming apparatus  100  according to the present example embodiment. The image forming apparatus  100  is a laser beam printer that forms an image onto a recording material P with use of the electrophotographic method. 
     The image forming apparatus  100  includes a cartridge  15  including a photosensitive drum  19  as an image bearing member, a charging roller  16  as a charging member, a development roller  17  as a development member, and a cleaning blade  18  as a cleaning member. In the present example embodiment, a development unit including the photosensitive drum  19 , the charging roller  16 , and the development roller  17 , and a cleaning unit including the cleaning blade  18  are configured in a manner detachably attachable to an apparatus main body of the image forming apparatus  100  as the process cartridge  15 . 
     The photosensitive drum  19  is rotationally driven at a predetermined circumferential speed (a process speed) in a counterclockwise direction. The charging roller  16  evenly charges a circumferential surface of the photosensitive drum  19  in such a manner that this surface has a predetermined polarity and potential (primary charging). The photosensitive drum  19  charged by the primary charging is subjected to scan and exposure (irradiation) of the charged surface thereof with laser light emitted from a laser scanner  21 . The laser scanner  21  as an image exposure unit outputs laser light on-off modulated in correspondence with a chronological electric digital pixel signal of target image information input from a not-illustrated external apparatus such as an image scanner and a computer. As a result, an electrostatic latent image corresponding to the target image information is formed on the photosensitive drum  19 , with electric charges removed from an exposed bright portion on the circumferential surface of the photosensitive drum  19  by this scan and exposure. 
     The development roller  17  bears a developer (toner) on a surface thereof and supplies the developer onto the circumferential surface of the photosensitive drum  19 , and sequentially develops the electrostatic latent image formed on the circumferential surface of the photosensitive drum  19  as a toner image. In the case of the laser printer, a generally employed method is a reversal development method, which develops the electrostatic latent image by attaching the toner to the exposed bright portion of the electrostatic latent image. 
     The recording material P is stacked and contained in a sheet feeding cassette  11  configured in a manner detachably attachable to the image forming apparatus  100 . The image forming apparatus  100  includes a sheet feeding roller  12 , which separates and feeds the recording material P one by one, a conveyance roller  13 , which conveys the recording material P, a registration roller  14 , which adjusts a timing of feeding the recording material P, and the like. The sheet feeding roller  12  is driven based on a sheet feeding start signal, by which the recording material P in the sheet feeding cassette  11  is separated and fed one by one, and is introduced to a transfer portion between the photosensitive drum  19  and a transfer roller  20  (a transfer member) by the registration roller  14  via the conveyance roller  13  at a predetermined timing. More specifically, the conveyance of the recording material P is controlled by the registration roller  14  so as to satisfy such a timing that, when a leading edge portion of the toner image on the photosensitive drum  19  reaches the transfer portion, a leading edge portion of the recording material P also reaches the transfer portion just at the same time. The image forming apparatus  100  may be configured in such a manner that the recording material P placed on a manual feeding tray  28  is separated and fed one by one by a sheet feeding roller  29 , and is introduced to the transfer portion between the photosensitive drum  19  and the transfer roller  20  by the registration roller  14  at the predetermined timing. 
     The recording material P introduced to the transfer portion is conveyed while being sandwiched through this transfer portion, and a transfer voltage (a transfer bias) controlled in a predetermined manner is applied from a not-illustrated transfer bias application power source to the transfer roller  20  during this time. Generally, the transfer roller  20  is embodied by an elastic sponge roller prepared by forming, on a core metal such as Fe, a semi-conductive sponge elastic layer adjusted so as to have resistance of approximately 1×10 6  to 1×10 10 Ω with use of carbon, an ionically conductive filler, or the like. In the present example embodiment, the image forming apparatus  100  uses an ionically conductive transfer roller prepared by causing a nitrile butadiene rubber (NBR) and a surfactant or the like to react with each other externally around the core metal concentrically and integrally, and shaping a conductive elastic layer into a roller-like form and providing it. The transfer roller used has a resistance value in a range of 1×10 8  to 5×10 8 Ω. 
     The transfer bias opposite in polarity from the toner is applied to the transfer roller  20 , by which the toner image formed on the circumferential surface of the photosensitive drum  19  is electrostatically transferred onto a surface of the recording material P at the transfer portion. The recording material P with the toner image transferred thereon is conveyed and introduced from the transfer portion to an image heating apparatus  200 , and is subjected to fixing processing for heating and pressing the toner image. Then, the recording material P with the toner image fixed thereon by the image heating apparatus  200  is discharged onto a sheet discharge tray on the image forming apparatus  100  by passing through a conveyance roller  26 , which conveys the recording material P. and a sheet discharge roller  27 , which discharges the recording material P. Then, the image formation is completed. 
     On the other hand, after the toner image is transferred onto the recording material P, the circumferential surface of the photosensitive drum  19  is used for the next image formation by being treated by a removal of transfer residual toner, paper dust, and the like with use of the cleaning blade  18  and being processed by the primary charging again. 
     (2) Example Image Heating Apparatus 
     Next, the image heating apparatus  200  based on the film heating method according to the present example embodiment will be described.  FIG. 2  is a schematic lateral cross-sectional view of the image heating apparatus  200  according to the present example embodiment, and  FIG. 3  is a schematic longitudinal cross-sectional view of the image heating apparatus  200  according to the present example embodiment. Further,  FIG. 4  is an exploded perspective view illustrating components of the image heating apparatus  200  according to the present example embodiment. The image heating apparatus  200  includes a film unit (a belt unit)  205 , a pressing roller (a rotational member)  208  as a pressing member, and a casing  203 , which houses them. 
     The pressing roller  208  is rotatably arranged while one end and the other end of a core metal  209  thereof are borne on side plates on one end side and the other end side of the casing  203  via bearing members  62 , respectively. A driving gear  47  is provided on the other end side of the core metal  209 , and the pressing roller  208  is configured to be drivable in a direction indicated by an arrow R 1  in  FIG. 2  as a driving rotational member in reaction to transmission of a driving force of a motor  30  controlled by a not-illustrated control unit (an engine controller) to the driving gear  47 . The pressing roller  208  includes the core metal  209 , an elastic body layer  210 , and a front layer  211 , which is an outermost layer. In the present example embodiment, an aluminum core metal, a silicon rubber, and a perfluoroalkoxy (PFA) tube approximately 50 μm in thickness are used as the core metal  209 , the elastic body layer  210 , and the front layer  211 , respectively. The outer diameter of the pressing roller  208  is set to 25 mm, and the thickness of the elastic body layer  210  is set to approximately 3 mm. 
     The film unit  205  includes a heater (a heating member)  300 , a support member  201 , a film  202 , and a stay  204 . The heater  300 , the support member (a guide member)  201 , which holds the heater  300  and also guides a rotation of the film  202 , and the stay  204 , which supports the support member  201 , are arranged inside the film  202  as an internal assembly. 
     In particular, a ceramic heater is used as the heater  300 , and the heater  300  is arranged in a state laid face up in such a manner that a surface on an opposite side from a front surface side of a substrate with a heating resistor and an insulative protection layer formed thereon faces the film  202 . The heater  300  is arranged in such a manner that the temperature thereof is detectable by a thermometer element (a thermistor)  212 . In the present example embodiment, an externally abuttable thermistor separated from the heater  300  is used as the thermometer element  212 . 
     The support member  201  is a thermally resistant and stiff member having a holding function of holding the heater  300  along a longitudinal direction on a bottom surface and a film guide function of guiding the rotation of the film  202 . The support member  201  can be prepared by using, for example, highly thermally resistant resin such as polyimide, polyamide-imide, polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and liquid crystal polymer, or a composite material of these kinds of resin and ceramics, metal, glass, and/or the like. In the present example embodiment, the liquid crystal polymer is used. The support member  201  is supported by the stay  204 , which is stiffer. In the present example embodiment, the stay  204  made of metal is used. 
     The film  202  is externally fitted to the support member  201  holding the heater  300  and functioning as the film guide member, and is configured in such a manner that an inner peripheral surface thereof can rotate around the support member  201  while contacting the heater  300 . Desirably, the film thickness of the film  202  is set to a thickness of 450 μm or thinner and 20 μm or thicker to reduce a thermal capacity thereof and thus reduce a waiting time (a first printout time). Further, examples usable as the film  202  include a single-layered film such as thermally resistant polytetrafluoroethylene (PTFE), PFA, and fluorinated ethylene propylene (FEP), or a multiple-layered film prepared by coating a film such as polyimide, polyamide-imide, PEEK, polyethersulfone (PES), and PPS with PTFE, PFA, FEP, or the like. In the present example embodiment, the image heating apparatus  200  uses a film prepared by coating an outer peripheral surface of a polyimide film 60 μm in film thickness with PFA. The thickness of the PFA coating layer is set to approximately 15 μm. The outer diameter of the film  202  is set to 24 mm. For the base layer of the film  202 , the usable materials include not only the above-described resin materials but also a metallic material such as stainless steel (SUS). A thermally resistant rubber such as a silicon rubber may be formed between the base layer and the coating layer as an elastic layer to improve an image quality. 
     Then, all of the heater  300 , the support member  201 , and the stay  204  are members having lengths longer than the width (the length) of the film  202 , and one end sides (left sides) and the other end sides (right sides) thereof protrude out of both ends of the film  202 , respectively. The film unit  205  further includes flanges  40  (a film holding member), and outward protrusion portions  204   a  on the one end side and the other end side of the stay  204  are inserted in the flanges  40  on the one end side and the other end side, respectively. In other words, the flanges  40  are disposed at both longitudinal end portions of the film  202 . Hereinafter, a “flange  40 L”, a “flange  40 R”, and “flanges  40 ” refer to the flange on the left side (the one end side), the flange on the right side (the other end side), and both the flanges on the left and right sides, respectively. 
     The flanges  40  are individually horizontally symmetrically-shaped mold product made of thermally resistant resin that are disposed on the both longitudinal end portions of the film  202 . Each of the flanges  40  includes an insertion target portion  40   d , in which the external protrusion portion  204   a  of the stay  204  is inserted, a groove portion  40   e , which is fixed to a vertical edge portion of a slit provided on the side plate of the casing  203 , and a force reception portion  40   c . The flange  40  is brought into such a state that the groove portion  40   e  is engaged with the vertical edge portion of the slit provided on the side plate of the casing  203  with the outward protrusion portion  204   a  of the stay  204  inserted in the insertion target portion  40   d . Due to this configuration, the flanges  40 L and  40 R are held vertically and slidably movable relative to the side plates, respectively. More specifically, the film unit  205 , as a whole, is configured movably in directions toward and away from the pressing roller  208  along the vertical guide slits between the side plates. 
     On the other hand, pressing springs  48 L and  48 R included in the image heating apparatus  200  are in abutment with the force reception portions  40   c  of the flanges  40 L and  40 R, respectively. The pressing spring  48 L and the pressing spring  48 R are compressively mounted between a spring bearing portion  203 L on the one end side of the casing  203  and the force reception portion  40   c  of the flange  40 L, and between a spring bearing portion  203 R on the other end side of the casing  203  and the force bearing portion  40   c  of the flange  40 R, respectively. As a result, biasing forces are applied to the outward protrusion portions  204   a  and  204   a  on the one end side and the other end side of the stay  204  of the film unit  205  via the flanges  40 L and  40 R with the aid of compressive mounting reaction forces of the pressing springs  48 L and  48 R, respectively. 
     Due to this configuration, the support member  201  including the heater  300  and the pressing roller  208  are in pressure contact with each other with a predetermined pressing force while sandwiching the film  202  against the elasticity of the elastic body layer  210  of the pressing roller  208 . In the image heating apparatus  200  according to the present example embodiment, the heater  300  functions as a nip portion formation member, and the support member  201  also functions as an abutting sliding member (a backup member) in contact with the inner peripheral surface of the film  202 . In this way, a nip portion N having a predetermined width in a sheet conveyance direction is formed between the film  202  and the pressing roller  208 . 
     In the image heating apparatus  200 , when a print signal is input from an external input apparatus such as a personal computer (PC), the pressing roller  208  is rotationally driven in the direction indicated by the arrow R 1  (the clockwise direction) by the motor  30  controlled by the control unit  400 . On the film  202 , a rotational force is transmitted from the pressing roller  208  to the film  202  due to a frictional force between the pressing roller  208  and the outer peripheral surface of the film  202  at the nip portion N, and the film  202  is rotationally driven as the inner peripheral surface of the film  202  is slidingly moved on the heater  300  at the nip portion N. In this manner, the film  202  is moved and rotated in a direction indicated by an arrow R 2  (a counterclockwise direction) around the support member  201  at approximately the same speed as a movement speed of the circumferential surface of the pressing roller  208 . 
     On the other hand, at the heater  300 , the heater  300  (the heating resistor) is caused to generate heat by supply of power from the control unit  400  as a driving unit connected to an alternating-current power source (an outlet)  401  via a power supply electrode of the heater  300 . The control unit  400  controls the power supply to the heater  300  using a not-illustrated triac provided to the control unit  400  based on information regarding the temperature of the heater  300  output from the thermistor  212 , thereby controlling the temperature of the heater  300 . More specifically, the heater  300  is kept at a constant temperature at the time of the fixing by being subjected to the control of the power supply thereto by the control unit  400  in such a manner that the temperature thereof is increased when the output from the thermistor  212  is an output according to a low temperature compared to a set temperature while the temperature of the heater  300  is reduced when the output from the thermistor  212  is an output according to a high temperature compared to the set temperature. 
     After the temperature of the heater  300  is raised to a predetermined temperature and the film  202  is brought into a state rotationally driven by the pressing roller  208 , the recording material P with the toner image transferred thereon is conveyed from the transfer portion to the nip portion N formed by the heater  300  and the pressing roller  208  via the film  202 . Then, the recording material P is sandwiched and conveyed through the nip portion N together with the film  202 , by which the heat of the heater  300  is applied to the recording material P via the film  202  and the unfixed toner image on the recording material P is heated and pressed, thereby being fixed onto the recording material P. The recording material P conveyed through the nip portion N is separated from the film  202  and is further conveyed. 
     (3) Example Detailed Configuration of Flange 
     In the following description, a configuration of the flange  40  in the image heating apparatus  200  according to the first example embodiment will be described. 
     The flange  40  includes a movable member  40 X, a biased member  40 Y, and springs  253 .  FIG. 5A  illustrates the movable member  40 X, and  FIG. 5B  illustrates the biased member  40 Y. At the flange  40 , the movable member  40 X is provided with a restriction surface  40   a , a guide surface  40   b , and the insertion target portion  40   d , and the biased member  40 Y is provided with the force reception portion  40   c  and the groove portion  40   e . For the movable member  40 X and the biased member  40 Y forming the flange  40 , resin containing glass fibers, such as PPS, liquid crystal polymer, polyethylene terephthalate (PET), and polyamide (PA) is used as a material that has high thermal resistance, small thermal conductivity, and excellent slidability, and PPS is used in the present example embodiment. 
     The groove portion  40   e  is engaged with the vertical edge portion of the slit provided on the side plate of the casing  203  with the outward protrusion portion  204   a  of the stay  204  inserted in the insertion target portion  40   d . Thus, the flange  40  is slidably configured and the force reception portion  40   c  is biased by the pressing spring  48  (L or R). In this manner, the flange  40  supporting the stay  204  is pressed toward the pressing roller  208 , resulting in the nip portion N formed between the pressing roller  208  and the flange  40 . 
     An operation of restricting a displacement of the fixing member according to the present example embodiment will be described.  FIG. 6A  illustrates a state in which the fixing film  202 , which is the fixing member, is not displaced, and  FIG. 6B  illustrates a state in which the fixing film  202  is displaced. 
     The restriction surface  40   a  faces an end surface  202   d  at the longitudinal end portion of the film  202 , and serves the role of restricting a movement (a displacement) when the film  202  moves longitudinally, so that the film  202  stays at a predetermined longitudinal position. In other words, the restriction surface  40   a  is configured in such a manner that, when the film  202  is displaced, the film end surface  202   d  abuts against the restriction surface  40   a  of the flange  40 , whereby displacement of the film  202  is restricted. 
     The guide surface  40   b  guides the inner peripheral surface of the rotating film  202  in a region at the longitudinal end portion of the film  202 . More specifically, the guide surface  40   b  serves the role of causing the film  202  to draw a desired rotational locus by supporting the inner peripheral surface at the longitudinal end portion of the film  202  from inside. When the inner peripheral surface at the end portion of the rotating film  202  and the guide surface  40   b  of the flange  40  contact each other and slidingly move on each other, the heat necessary in fixing the toner is deprived by the flange  40 . Therefore, the guide surface  40   b  of the flange  40  is positioned in a region longitudinally outside a conveyance region Wmax of the recording material P having a maximum size on which the toner is fixable by the image heating apparatus  200 . 
     Further, in the present example embodiment, a lubricant application unit  260  is provided on the guide surface  40   b  at a portion thereof in abutment with the fixing film  202 . Examples usable as the lubricant application unit  260  include a lubricant supply member made from, for example, porous fluororesin, a Nomex felt, a Nomex braid, a Nomex fiber bundle, a glass fiber bundle, a carbon fiber bundle, a carbon felt, an aramid fiber bundle, or a polyimide foam. Further, grease prepared by thickening perfluoro polyether base oil with fluororesin, or a thermally resistant lubricant such as silicon oil including dimethyl silicone can be used as a lubricant permeating or penetrating into the lubricant supply member. 
     The movable member  40 X is disposed adjacent to the biased member  40 Y via the springs  253  while supporting the stay  204  with the outward protrusion portion  204   a  of the stay  204  inserted in the insertion target portion  40   d . At the flange  40 , the biased member  40 Y is disposed longitudinally outside the movable member  40 X without the springs  253  compressed in a state not subjected to application of an external force. The movable member  40 X includes a protrusion portion  40   f  protruding longitudinally outward, and includes a sliding portion  40   f  longitudinally outside the protrusion portion  40   f . The sliding portion  40   f  extends further longitudinally outward as stretching from a downstream side toward an upstream side in the movement direction of the recording material P at the nip portion N. On the other hand, the biased member  40 Y includes a recessed portion  40   g  for accommodating the protrusion portion  40   f , and includes an inclined surface  40   g ′ longitudinally outside the recessed portion  40   g . The inclined surface  40   g ′ extends further longitudinally outward as stretching from the downstream side toward the upstream side in the movement direction of the recording material P at the nip portion N. 
     In this manner, when the film  202  is displaced and causes the restriction surface  40   a  to move to the longitudinal end portion, the springs  253  are compressed. As a result, the sliding portion  40   f  of the movable member  40 X contacts the inclined surface  40   g ′ of the biased member  40 Y, and the movable member  40 X moves upstream in the recording material conveyance direction at the nip portion N along the inclined surface  40   g ′. When the movable member  40 X moves upstream and pushes up the end portion of the fixing film  202  upstream in the conveyance direction of the recording material P, the orientation of the fixing film  202  is changed and contributes to reducing the displacement of the fixing film  202 . In the present example embodiment, as illustrated in  FIG. 6B , the fixing film  202  is displaced and the movable member  40 X moves upstream in the conveyance direction of the recording material P, by which the lubricant application unit  260  abuts against the inner peripheral surface of the fixing film  202 . As a result, not only the lubricant is applied onto the inner peripheral surface of the fixing film  202  but also shaved powder generated due to sliding friction between the fixing film  202  and the guide surface  40   b  is collected by the lubricant application unit  260 . In this manner, the movable member  40 X abuts against the inner peripheral surface of the fixing film  202  and generates the sliding friction therebetween when the movable member  40 X pushes up the end portion of the fixing film  202  upstream. As a result, the lubricant application unit  260  abuts against only a part of the inner peripheral surface of the fixing film  202  without abutting against the entire circumference of the inner peripheral surface of the fixing film  202 , thereby reducing the sliding resistance between the lubricant application unit  260  and the fixing film  202 . 
     According to the present example embodiment, providing the lubricant application unit  260  at the flange  40  of the fixing member can reduce the wear on the inner peripheral surface of the fixing member with a simple structure and also can reduce a defect such as an image streak due to the shaved powder, thus being able to prolong the product lifetime of the image heating apparatus  200 . 
     As illustrated in  FIG. 7 , a lubricant storage container  262 , which supplies the lubricant to the lubricant application unit  260 , may be provided. The lubricant storage container  262  is provided in the movable member  40 X as indicated by a dotted line in  FIG. 7 , and is provided connectably with the lubricant application member. Configuring the image heating apparatus  200  in this manner allows the lubricant to be stored in advance and supplied from the lubricant storage container  262  to the lubricant application member  260 , thereby allowing the lubricant to be further prevented from being depleted. 
     While the present disclosure has been described with reference to example embodiments, it is to be understood that the disclosure is not limited to the disclosed example embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2018-245426, filed Dec. 27, 2018, which is hereby incorporated by reference herein in its entirety.