JP2018116268A - Image heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image heating device capable of improving durability of a film with a simple structure.SOLUTION: An image heating device comprises: a cylindrical film; a contact member which contacts an inner face of the film; a nip part formation member for forming a nip part on which a recording material on which an image is formed is transported, and heated, and an image is fixed to the recording material, with the contact member through the film; and a regulation member provided on a longitudinal end part of the film, and has an inner face regulation surface facing the inner face of the film and regulates a position of the inner face of the film. The inner face regulation surface has a first region separated from the nip part by the largest distance, and a second region closer to the nip part than the first region, in a rotation direction of the film when viewing the film in the longitudinal direction, and the first region and the second region are inclined so as to separate from the inner face of the film as approaching to a longitudinal center of the film in the longitudinal direction of the film, in which an inclination angle of the first region is larger than an inclination angle of the second region.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image heating apparatus suitable for use as a fixing device mounted on a copying machine, a printer, a fax machine, and an image forming apparatus such as a multifunction machine having a plurality of these functions.

  2. Description of the Related Art A film (belt) heating type device is known as a fixing device (image heating device) attached to an image forming apparatus. Specifically, a pressure roller (second rotating body) is brought into pressure contact with a rotating body (first rotating body) such as a flexible cylindrical fixing film containing a ceramic heater so that both rotating bodies are in contact with each other. A nip portion is formed between them. A recording material (recording medium) carrying an unfixed image is inserted into the nip portion, and the unfixed image is heated and pressurized. In this way, the unfixed image is fixed to the surface of the recording material.

  In this film heating type apparatus, it is necessary to regulate the shifting movement of the fixing film (hereinafter referred to as film), that is, the shifting movement of the film in the thrust direction. As one of the restricting means, a film holding member (hereinafter referred to as a flange) for receiving and restricting movement of the film end on that side is disposed on both ends or one end of the film.

  In addition to the above role, the flange also has a role of regulating the rotational running shape of the film by having an inner surface regulating surface of the film. By making the shape of the inner surface regulating surface close to the natural rotational shape of the film, such as an ellipse that is long in the upstream / downstream direction in the recording material conveyance direction, fatigue phenomena such as film breakage are less likely to occur. On the other hand, when the inner diameter of the film is small or the built-in objects in the film are large, it may be restricted to a shape that is closer to a perfect round than the natural rotating shape of the film in order to prevent contact with the built-in objects. is there.

  If the film is driven to rotate in this state, the film and the flange will continue to be rubbed strongly at the raised portion. As a result, the inner peripheral surface of the film and the inner surface regulating surface of the flange are likely to be worn and deteriorated, and eventually the film end portion is torn and becomes unusable. In addition, this phenomenon is further promoted when the film rotates at higher speed as the speed of the image forming apparatus increases. For this reason, in the film heating type apparatus, wear of the film has become a bottleneck in increasing the speed while reducing the size.

  In patent document 1, the natural material which does not contain glass fiber is used for the inner surface regulation surface of a flange. Thereby, compared with resin containing glass fiber, smoothness and surface roughness are improved, damage to the film is reduced by improving slipperiness, and a configuration that can contribute to longer life has been proposed. . More specifically, the surface portion in contact with the film is formed of a natural material, and the other base material portion is formed of a resin containing glass fibers and bonded to function as a flange. This two-part configuration serves two purposes: reducing damage to the film and enhancing the mechanical strength of the flange itself.

JP 2002-246151 A

  The present invention is a further development of this prior art, and its object is to provide an image heating apparatus that improves the durability of the film with a simple structure.

A typical configuration of the image heating apparatus according to the present invention for achieving the above object is as follows:
A tubular film,
A contact member that contacts the inner surface of the film;
A nip portion forming member that forms a nip portion together with the contact member via the film, wherein the recording material on which the image is formed is heated while being conveyed, and the image is fixed to the recording material;
A regulating member provided at a longitudinal end portion of the film and having an inner surface regulating surface facing the inner surface of the film and regulating the position of the inner surface of the film;
The inner surface regulating surface, when viewed in the longitudinal direction of the film, with respect to the rotation direction of the film, a first region farthest from the nip portion and a second region closer to the nip portion than the first region And having
The first region and the second region are inclined away from the inner surface of the film toward the longitudinal center of the film with respect to the longitudinal direction of the film. Is greater than the tilt angle of the second region,
It is characterized by that.

In addition, another typical configuration of the image heating apparatus according to the present invention for achieving the above object is as follows:
A tubular film,
A contact member that contacts the inner surface of the film;
A nip portion forming member that forms a nip portion together with the contact member via the film, wherein the recording material on which the image is formed is heated while being conveyed, and the image is fixed to the recording material;
A regulating member provided at a longitudinal end portion of the film and having an inner surface regulating surface facing the inner surface of the film and regulating the position of the inner surface of the film;
The inner surface regulating surface, when viewed in the longitudinal direction of the film, with respect to the rotation direction of the film, a first region farthest from the nip portion and a second region closer to the nip portion than the first region And having
The first region is inclined so as to be away from the inner surface of the film as it goes toward the longitudinal center of the film with respect to the longitudinal direction of the film, and the second region extends over the longitudinal direction of the film. The distance to the inner surface of
It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the image heating apparatus which improves the durability of a film with simple structure can be provided.

Illustration explaining the shape of the flange Schematic configuration schematic diagram of an example of an image forming apparatus Schematic diagram of the front part of the fixing device, omitting the middle part Longitudinal front view of the fixing device Cross-sectional left side view of the fixing device (A) is a schematic exploded perspective view of a film unit, (b) is a schematic cross-sectional view of a heater. Flange structure illustration Block diagram of control system Illustration explaining the rotation trajectory of the film Illustration explaining the rotation trajectory of the film Diagram explaining the arrangement of film and flange Illustration explaining the shape of the flange Diagram explaining the profile of the inner surface of the film Diagram explaining the arrangement of film and flange Illustration explaining the shape of the flange Diagram explaining the contact area of the flange Diagram explaining wear on the inner surface of the film Illustration explaining the shape of the flange Diagram explaining the arrangement of film and flange Diagram explaining the arrangement of film and flange Diagram explaining the arrangement of film and flange Illustration explaining the shape of the flange Diagram explaining the arrangement of film and flange Explain the shape of the flange Illustration explaining the shape of the flange Illustration explaining the shape of the flange Diagram explaining wear on the inner surface of the film

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

Example 1
[Image forming apparatus]
FIG. 2 is a schematic diagram illustrating a schematic configuration of an example of the image forming apparatus 100 in which the image heating apparatus according to the present invention is mounted as the fixing device 130. The image forming apparatus 100 is a monochrome printer using an electrophotographic process.

  In the image forming apparatus 100, an image forming unit 101 that forms a toner image on a recording material (hereinafter referred to as paper or paper) S is a photosensitive drum (hereinafter referred to as drum) 102 that is driven to rotate as an image carrier. And a charging member 103 for charging the drum surface. The image forming unit 101 further includes a laser scanner 104 that performs image exposure on the charging surface of the drum 102, a developing unit 105 that develops the electrostatic latent image formed on the drum surface with toner, a transfer member 106, and a drum cleaner 107. Have

  The drum 102, the charging member 103, the developing device 105, and the drum cleaner 107 are integrally configured as a process cartridge 108 that is detachably attached to the apparatus main body 100A. Since the above-described image forming operation (electrophotographic process) of the image forming unit 101 is well known, detailed description thereof is omitted. Regarding the specifications of the image forming apparatus 100 used in this embodiment, the process speed is 350 mm / sec. It is.

  The sheets S stored in the cassette 109 in the apparatus main body 100A are fed out one by one by the rotation of the sheet feeding roller 110. The sheet S is introduced at a predetermined control timing into a transfer nip 113 formed by the drum 102 and the transfer member 106 through a conveyance path 111 having a pair of registration rollers 112, and receives a toner image on the drum 102 side. . The sheet S exiting the transfer nip portion 113 is sent to a fixing device (fixing portion) 130 through a conveyance path 114 and subjected to a toner image heat pressure fixing process. The sheet S exiting the fixing device 130 passes through the conveyance path 115 and is discharged to the tray 117 as an image formed product (product) by the discharge roller 116.

[Fixing device]
With respect to the fixing device 130, the front is the entrance side of the sheet S, and the back is the exit side. Left and right are left (one end side) or right (other end side) when the device 130 is viewed from the front. Up and down are up or down in the direction of gravity. The upstream side and the downstream side are the upstream side and the downstream side in the paper transport direction (recording material transport direction). In addition, the axial direction of the pressure roller or a direction parallel to the axial direction is defined as a longitudinal direction, and a direction orthogonal thereto is defined as a short direction.

  The fixing device 130 is an image heating device (OMF: on-demand fixing device) of a film (belt) heating type that can shorten the start-up time and reduce power consumption. 3 is a schematic front view of the device 130, FIG. 4 is a schematic front sectional view of the device 130, and FIG. 5 is a schematic left side view taken along line (5)-(5) in FIG. The fixing device 130 is roughly divided into a film unit (belt unit) 150, an elastic pressure roller (drive rotary member) 134 as a pressure member, and a device frame (housing) 160 that houses them. Have.

(1) Film unit 150
FIG. 6A is an exploded perspective schematic view of the film unit 150. The unit 150 is a fixing film (fixing belt: a first rotating body having a flexible cylindrical shape (endless shape) that is loosely fitted to an internal assembly (built-in object: internal member). (Hereinafter referred to as a film) 133. Inside the film 133 are a heater 132 as a heating element, a guide member (holding member) 131 that holds the heater 132 and guides the rotation of the film, and a pressure rigid stay 140 made of, for example, iron that holds the guide member 131. It is arranged as an assembly. The heater 132 is a contact member that contacts the inner surface of the film 133.

  Each of the heater 132, the guide member 131, and the stay 140 is a member having a length longer than the width (length) of the film 133, and one end side (left side) and the other end side (right side) are respectively from both end portions of the film 133. It protrudes outward. A flange (film holding member) 139 (L / R) on one end side and the other end side is fitted to the outward projecting portions 140a on one end side and the other end side of the stay 140, respectively. That is, the flanges 139 (L · R) are arranged at both ends in the longitudinal direction of the film 133.

1) Film 133
The flexible tubular film 133 is provided so that the inner peripheral length is larger than the outer peripheral length of the guide member 131 supporting the heater 132. Accordingly, the film 133 is externally fitted to the guide member 131 with a sufficient margin in the circumference. In this embodiment, a film having an inner diameter of φ24 is used.

  Since the film 133 efficiently applies the heat of the heater 132 to the paper S as the material to be heated at the nip portion N formed together with the pressure roller 134, the film 133 has a heat resistance of PTFE, PFA, FEP, etc. Single layer film can be used. Alternatively, a composite layer film can be used.

As the composite layer film, generally, a film having a three-layer structure of a base layer, an elastic layer formed on the outer periphery for the purpose of improving fixability, and a release layer on the outermost surface is used. The base layer is, for example, polyimide, polyamideimide, PEEK, PES, PPS or SUS. The elastic layer is a material obtained by mixing a heat conductive filler such as ZnO, Al ₂ O ₃ , SiC, or metal silicon in an elastic material such as silicone rubber. The release layer is, for example, a coating layer such as PTFE, PFA, FEP.

  In this example, a polyimide made conductive by mixing a 50 μm thick filler as a base layer, a 240 μm thick silicone rubber-heat conductive filler mixed layer as an elastic layer, and PTFE coated on the outermost surface were used.

  Here, PTFE is polytetrafluoroethylene. PFA is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. FEP is a tetrafluoroethylene-hexafluoropropylene copolymer. PES is a polyethersulfone.

2) Heater 132
A ceramic heater is generally used as the heater 132 as the contact member. As the heater substrate, a ceramic substrate with good thermal conductivity and insulation made of ceramic such as alumina or aluminum nitride is used. The thickness of the ceramic substrate (hereinafter referred to as the substrate) is suitably about 0.5 to 1.0 mm in order to reduce the heat capacity, and is formed in a rectangle having a width of about 10 mm and a length of about 300 mm. .

  FIG. 6B is a schematic enlarged cross-sectional view of the heater 132. On one surface (front surface) of the heater substrate 132a, a resistance heating element 135 is formed along the longitudinal direction. The resistance heating element 135 is mainly composed of a silver palladium alloy, a nickel tin alloy, a ruthenium oxide alloy or the like, and is formed to have a thickness of about 10 μm and a width of about 1 to 5 mm by screen printing or the like.

  The surface of the heater substrate 132a where the resistance heating element 135 is formed is overcoated with an insulating glass 136 as an electrical insulating layer. The insulating glass 136 has a role of preventing mechanical damage and the like as well as ensuring insulation between the resistance heating element 135 and the external conductive member (conductive layer of the film 133). A thickness of about 20 to 100 μm is appropriate. The insulating glass 136 also has a role as a sliding layer that slides on the film 133.

3) Guide member 131
The guide member 131 is a member formed of a heat resistant resin, and supports the heater 132 and also serves as a conveyance guide for the film 133. A groove portion is formed along the length of the lower surface of the guide member 131, and the heater 132 is fitted and supported in the groove portion with the surface side facing outward.

  The material of the guide member 131 can be composed of a highly heat-resistant resin excellent in processability such as polyimide, polyamideimide, polyetheretherketone, polyphenylene sulfide, liquid crystal polymer, or a composite material such as these resins and ceramics, metal, glass, etc. . In this example, a liquid crystal polymer was used.

4) Flange 139
The flanges 139 (LR) arranged at both ends in the longitudinal direction of the film 133 are molded products made of heat-resistant resin having symmetrical shapes. 7A, 7B, and 7C are views of the flange 139 as viewed from the inner surface side, the side surface side, and the top surface side, respectively. (D) is a longitudinal cross-sectional view. As shown in these drawings, the flange 139 includes an inner periphery restricting portion (inner surface restricting member) 139a, an end restricting portion 139b, a pressure receiving portion 139c, a fitting portion 139d with respect to the outward projecting portion 140a of the stay 140, and the device. It has the fitting vertical groove part 139e with respect to the frame 160. FIG.

  The inner periphery restricting portion (inner surface restricting member) 139a has a contact region (hereinafter referred to as an inner surface restricting surface) 139f facing the inner peripheral surface of the end portion of the film 133. The inner periphery restricting portion 139a plays a role of causing the film 133 to draw a desired rotation locus by restricting the end portion of the film 133 from the inside.

  In the present embodiment, the outer shape of the inner periphery regulating portion 139a is a shape in which a lower portion of a substantially perfect circle of φ24.2 is cut out. As a result, fishing is performed in comparison with the natural rotational shape of the film 133, and many built-in objects such as the thermistor 138 and the pressure rigid stay 140 are accommodated in the film.

The end regulating part 139b faces the longitudinal end surface (longitudinal end part) of the film 133, and plays a role of regulating the movement of the film 133 in the longitudinal direction when the film 133 moves in the longitudinal direction. The end restricting portion 139b is provided outside the inner surface restricting portion 139a in the longitudinal direction of the film 133.
The pressure receiving portion 139c is in direct contact with the pressure rigid stay 140 and plays a role of pushing down the pressure rigid stay 140 by the pressure spring 164 (LR) that is contracted.

  Flange 139 (L / R) has excellent heat resistance, relatively poor thermal conductivity, and excellent slip resistance, and glass fiber-containing resins such as PPS, liquid crystal polymer, PET, and PA are used. In this embodiment, PPS is used. Further, in this embodiment, the inner periphery restricting portion 139a and the end restricting portion 139b are integrally formed, but may be configured by separate parts.

(2) Pressure roller 134
The pressure roller 134 as a second rotating body (pressure member: nip portion forming member) forms a nip portion N between the film 133 and the heater 132 and rotationally drives the film 133. It is a member.

  The pressure roller 134 is an elastic roller formed of an elastic layer 134b formed by foaming heat-resistant rubber such as silicone rubber or fluorine rubber or silicone rubber on the outer peripheral side of a metal core 134a such as SUS, SUM, or Al. . In the pressure roller 134, a release layer 134c such as PFA, PTFE, FEP or the like may be formed on the elastic layer 134b. In this embodiment, an aluminum core bar 134a was used, 4.0 mm thick silicone rubber was used for the elastic layer 134b, and 50 μm thick PFA was used for the release layer 134c.

  The pressure roller 134 is rotatably disposed by bearing shaft portions on one end side and the other end side between side plates 161L and 161R on one end side and the other end side of the apparatus frame 160 via a bearing member 162, respectively. Yes. A drive gear G is disposed concentrically on the shaft portion on the other end side. The driving force of the motor M controlled by the control unit (engine controller) 50 (FIG. 8) is transmitted to the gear G via a drive transmission unit (not shown), so that the pressure roller 134 serves as a driving rotating body. In FIG. 5, it is rotationally driven at a predetermined peripheral speed in the direction of arrow R134.

  The film unit 150 is arranged between the side plates 161 </ b> L and 161 </ b> R of the apparatus frame 160 with the heater 132 facing downward and arranged substantially parallel to the pressure roller 134 above the pressure roller 134. The flanges 139L and 139R of the film unit 150 have engaging vertical groove portions 139e engaged with the vertical edge portions of the vertical guide slits 163 and 163 provided in the side plates 161L and 161R, respectively.

  Thus, the flanges 139L and 139R are held so as to be slidable in the vertical direction with respect to the side plates 161L and 161R, respectively. That is, the film unit 150 as a whole has a degree of freedom of movement between the side plates 161L and 161R along the longitudinal guide slits 163 and 163 in the direction approaching and the distance from the pressure roller 134.

(3) Pressure mechanism Pressure levers 165L and 165R pressed by pressure springs 164L and 164R are in contact with the pressure receiving portions 139c of the flanges 139L and 139R, respectively. The pressure spring 164L is contracted between the spring receiving portion 167L on one end side of the top plate 166 of the apparatus frame 160 and the pressure lever 165L. The pressure spring 164R is contracted between the spring receiving portion 167R on the other end side of the top plate 166 of the apparatus frame 160 and the pressure lever 165R.

  Due to the contraction reaction force of the pressure springs 164L and 164R, predetermined equal pressing forces are applied to the outward projecting portions 140a and 140a on one end side and the other end side of the stay 140 of the film unit 150 via flanges 139L and 139R, respectively. Is working.

  As a result, the guide member 131 having the heater 132 and the pressure roller 134 are pressed against each other with a predetermined pressure while sandwiching the film 133 against the elasticity of the elastic layer 134b of the pressure roller 134. In the fixing device 130 of this embodiment, the heater 132 or a part of the heater 132 and the guide member 131 functions as a sliding member (a backup member) that comes into contact with the inner surface of the film 133. Therefore, as shown in FIG. 5, a nip portion N having a predetermined width is formed between the film 133 and the pressure roller 134 in the paper conveyance direction a.

(4) Fixing Operation As described above, the driving force of the motor M controlled by the control unit 50 is transmitted to the gear G of the pressure roller 134 via the drive transmission unit, so that the pressure roller 134 is driven to rotate. The body is rotated at a predetermined peripheral speed in the direction of arrow R134 in FIG. Due to the rotation of the pressure roller 134, a rotational force acts on the film 133 by a frictional force with the pressure roller 134 in the nip portion N. As a result, the inner surface of the film 133 substantially corresponds to the rotational peripheral speed of the pressure roller 134 in the direction of the arrow R133 while the inner surface of the film 133 slides in close contact with the surface of the heater 132 and a part of the outer surface of the guide member 131 at the nip portion N. Driven at the peripheral speed.

  On the other hand, the heater 132 receives heat supply from the power supply unit 51 controlled by the control unit 50 via a power supply path (not shown) and rapidly generates heat. The temperature of the heater 132 is detected by a thermistor 138 disposed in contact with the back surface of the heater, and detected temperature information is input to the control unit 50. The control unit 50 appropriately controls the current that flows from the power feeding unit 51 to the heater 132 according to the detected temperature information that is input, thereby raising the temperature of the heater 132 to a predetermined temperature and maintaining the temperature. Adjust.

  The thermistor 138 is an element for detecting the temperature at the center in the longitudinal direction of the heater 132. The temperature detected by the thermistor 138 is input to the control unit 50. The thermistor 138 is an NTC (Negative Temperature Coerricient) thermistor, and its resistance value decreases as the temperature rises. The temperature of the ceramic heater 132 is monitored by the control unit 50, and the power supplied to the heater 132 is adjusted by comparing with the target temperature set in the control unit. Thereby, the electric power supplied to the heater is controlled so that the heater maintains the target temperature.

  In this way, the pressure roller 134 is driven to rotate, and the film 133 is driven and rotated accordingly, and the heater 132 is raised to a predetermined temperature and temperature-controlled, so that the image forming unit 101 side is undetermined. The sheet S carrying the adhered toner image T is introduced into the nip portion N. The sheet S is introduced into the nip portion N so that the carrying surface of the toner image T faces the film 133 and is nipped and conveyed.

  As a result, the unfixed toner image T on the paper is heated and pressed to be fixed as a fixed image. The sheet S that has passed through the nip N is separated from the surface of the film 133 by the curvature, and is discharged and conveyed from the fixing device 130. That is, the sheet S on which the toner image T is formed is heated while being conveyed in the nip portion N, and as a result, the toner image T is fixed on the sheet S.

(5) Film rotation trajectory FIGS. 9A and 9B show that the flanges 139 are not attached to both ends of the film 133, that is, the both ends of the film are not restricted by the inner circumference restricting portion 139a of the flange. It is a schematic diagram of the front and cross section of the film and the pressure roller when the pressure roller 134 is rotationally driven. The film 133 receives the driving force of the pressure roller 134 at the nip portion N and rotates.

  The film 133 receives a force in the rotation direction from the pressure roller 134 at the nip portion N, but the polyimide that is the base layer material of the film 133 does not have high rigidity. Therefore, the film 133 travels while maintaining a short elliptical shape in the pressing direction as shown in (b).

  On the other hand, when flanges 139 (L · R) whose inner circumference restricting portions 139a have a substantially perfect circle shape are attached to both ends of the film 133, the vehicle travels along the rotation locus shown in FIG. As shown in the front view of (a), the rotation trajectory of the film 133 is different between both ends and the center of the film 133 regulated by the flange 139 (LR). The solid lines in (b) and (c) indicate the rotation trajectory at the center and the end in the longitudinal direction of the film 133, and the dotted line indicates the rotation trajectory of the film 133 when not regulated by the flange 139 (FIG. 9). Yes.

  Since the inner periphery of the end of the film 133 is restricted by the inner circumference restricting portion 139a having a substantially perfect circle shape, the film 133 travels on a rotation locus close to a substantially perfect circle shape. On the other hand, since the inner periphery is not restricted at the center of the film 133, it is slightly elliptical, but it has a shape that is lifted directly above the case where both ends of the film are not restricted by the inner periphery restricting part 139a. Rotating.

  When flanges 139 (LR) are attached to both ends of the film 133, the rotation trajectory is different between the longitudinal center portion and the end portion of the film 133, and the film 133 bends at the longitudinal center portion. In this case, the film 133 receives both “the force for restricting the film into a substantially perfect circle shape” and “the force for becoming a natural elliptical shape”. Then, the film 133 and the flange 139 rub against each other strongly at the innermost point of the inner circumference restricting portion 139a of the flange 139, that is, the arrow portion J in FIG.

  If the fixing device 130 is continuously used in this state, the inner circumferential surface of the film 133 and the inner surface regulating surface 139f that is a contact region facing the inner circumferential surface of the inner circumferential regulating portion 139a are likely to be worn and deteriorated. In some cases, the end of the film will tear and become unusable.

  Conventionally, in order to prevent such a problem, as shown in FIG. 12, an R is provided at the innermost point of the inner periphery restricting portion 139a, and a flange shape is introduced so that the film 133 and the flange 139 do not slide strongly. However, when both the reduction in the diameter of the film 133 and the substantially perfect circular shape of the inner periphery restricting portion 139a of the flange 139 are compatible, the plane of the inner surface restricting surface 139f indicated by the arrow K even if such a configuration is adopted. The rubbing pressure becomes high at the part where the arc starts from the part. Further, when the film 133 rotates at a higher speed, this phenomenon is promoted, which has been a bottleneck in increasing the speed and life of the image forming apparatus.

  In the present embodiment, in order to solve this problem, the inclination angle of the inner surface regulating surface 139f of the inner circumference regulating portion 139a is optimized, and details thereof will be described in the following item (6).

(6) Angle of flange inner circumference restricting portion The following three items are related to the sliding pressure between the inner peripheral surface of the film 133 and the innermost point J (FIG. 11) of the inner circumference restricting portion 139a of the flange 139. is there.

  The first is the ease with which the film 133 bends. These may vary depending on various factors such as the inner diameter and longitudinal dimension of the film 133, the material of the base layer of the film 133, and the presence or absence of an elastic layer.

  The second is the shape of the inner periphery restricting portion 139a. While the diameter of the film 133 has been reduced from the viewpoint of low heat capacity and the like, the number of built-in items of the film 133 such as many safety elements has increased, and the inner periphery restricting portion 139a has a natural shape such as a substantially perfect circle. The shape is often different from the elliptical shape.

  In many cases, the configuration of these two elements is determined by the required performance of the fixing device 130. The third is the inclination angle of the inner surface regulating surface 139f. In this embodiment, this item is optimized. And give details.

  FIG. 1A shows an inner surface view of the flange 139, and a point G indicates the center of gravity as viewed from the inner circumference regulating portion 139a. (B) is a side view of the flange 139R, showing the inclination angle of the inner surface regulating surface 139f of the inner circumference regulating portion 139a. In (b), a line connecting the center of gravity G of the inner periphery restricting portion 139a of the two flanges 139 (LR) at both ends of the film and the same G '(the centers of gravity of the inner periphery restricting portions 139a at both ends of the film are connected. The bus bar Q is defined as a bar).

  An angle formed by a line P extending from the inner surface regulating surface 139f of the inner circumference regulating portion 139a and the bus bar Q is defined as θ, and this angle θ is defined as an inclination angle of the inner surface regulating surface 139f. In many cases, the bus Q is parallel to the center of gravity (rotation axis or bus) of the film 133 and the pressure roller 134. Therefore, the above-mentioned bus Q can be defined as the bus of the film 133 which is the first rotating body incorporated in the apparatus. That is, the inner surface regulating surface 139f is inclined so as to be away from the inner surface of the film 133 toward the longitudinal center of the film 133 with respect to the longitudinal direction of the film 133.

  Since the relationship between the deflection of the film 133 and the inner periphery regulating portion 139a varies depending on the value of the angle θ, the way of contact between the film inner circumferential surface and the inner surface regulating surface 139f varies. As shown in FIG. 11, when the inner surface regulating surface 139f is horizontal with the bus bar Q, or when the angle θ is close to 0 °, the film inner surface and the innermost surface J are rubbed strongly at the innermost point J of the inner surface regulating portion 139a. 133 and the inner circumference restricting portion 139a will lead to wear and deterioration.

  FIG. 13 shows the profile of the inner surface of the film when printing is performed for 5 hours using a flange 139 (LR) having an inclination angle θ of the inner surface regulating surface 139f of 0.5 °. The profile from the longitudinal center to the end of the film 133 is shown, and it can be seen that the inner surface of the film is scraped at a portion of 5 mm from the end. This indicates that the inner surface of the film has been scraped at the innermost point J of the inner circumference regulating portion 139a.

  In the present embodiment, as shown in FIG. 14, θ is increased, and the bending of the film 133 and the inclination angle of the inner surface regulating surface 139f are made closer. By doing so, the film 133 is not rubbed strongly at the innermost point J of the inner periphery restricting portion 139a, and the wear and deterioration of the film and flange are alleviated. In the following, experiments were conducted to confirm these effects.

<Experiment 1>
The contact between the film 133 and the inner periphery restricting portion 139a when the inclination θ of the inner restricting surface 139f was changed was examined. First, the image forming apparatus main body used was the one described in this embodiment. Regarding the fixing device 130, nine types of inclination angles θ of the inner surface regulating surface 139 f of the flange 139 are prepared in increments of 0.5 ° between 0 ° and 4 °.

  Next, grease was applied to the inner surface of the film 133 in order to confirm contact between the film 133 and the inner periphery regulating portion 139a. Since the grease adheres to the portion of the inner surface regulating surface 139f that is in contact with the film 133 when the film 133 rotates, the contact portion U can be observed as shown in FIG.

  Nine types of fixing devices were used for printing for 2 minutes each, and the areas where grease was adhered after the printing was compared.

  The experimental results are shown in Table 1 and FIG. When the angle θ of the inner periphery restricting portion 139a (inner surface restricting surface 139f) is small, the length of the contact portion U is 5 mm and hits the entire area of the inner surface restricting surface 139f. As θ increases, the angle of the inner surface regulating surface 139f becomes larger than the deflection of the film 133, and the inner side of the inner surface regulating surface 139f gradually does not touch the film 133. When θ is 3 ° or more, the film 133 is in contact only in a half region of the inner surface regulating surface 139f, and the effect of lifting the film 133 is reduced, which is not preferable from the viewpoint of securing space for the built-in film. It can be said.

<Experiment 2>
The amount of wear on the inner surface of the film when the angle θ of the inner surface regulating surface 139f was changed was examined. The same image forming apparatus main body and fixing device as those in Experiment 1 were prepared. Next, each of the image forming apparatus main body and the fixing device was used for printing for about 100 hours, and the amount of wear on the inner surface of the film that was in sliding contact with the inner surface regulating surface 139f at that time was compared.

  The experimental results are shown in Table 2 and FIG. When the angle θ was close to 0 °, the innermost point of the inner circumference restricting portion 139a rubbed strongly with the inner surface of the film, and the base layer thickness of 50 μm was completely worn out. As the angle θ increases, the rubbing with the innermost point J of the inner periphery restricting portion 139a becomes weaker, and when it is 2.0 ° or more, the innermost point J and the film 133 are not in contact with each other. It became less. The wear amount of the film 133 is desirably suppressed to about 10 μm, and the inclination angle θ of the inner surface regulating surface 139f is desirably 1.5 ° or more (1.5 ° or more).

  From the experiment, when the inclination angle θ of the inner surface regulating surface 139f is smaller than 1.5 °, it is not desirable from the viewpoint of wear of the film inner surface. When the angle θ is larger than 3.0 °, the effect of lifting the film 133 is reduced.

From the above results, regarding the problem of wear of the film 133, the inclination angle of the inner surface regulating surface 139f is preferably 1.5 ° or more. Further, considering the lifting effect of the film 133, it is desirable to set the inclination angle θ of the inner surface regulating surface 139f between 1.5 ° and 3.0 °. The friction between the film 133 and the flange 139 at the inner periphery regulating portion 139a has been described. Next, the contact between the film 133 other than the film fishing part of the flange 139 and the inner periphery regulating part 139a of the flange 139 will be described.

  FIG. 18 is an inner surface view of the flange 139L (R), and is a diagram in which the region of the inner periphery restricting portion 139a is divided into three. The sheet S is conveyed from the left side to the right side in the drawing at the nip portion N. The left side in the drawing is the upstream side of the nip portion N, and the right side is the downstream side of the nip portion N.

  An upstream end point (upstream end point) of the inner circumference regulating portion 139a is defined as A point. A downstream end point (downstream end point) of the inner circumference regulating portion 139a is a B point. A point on the inner circumference restricting portion farthest from the nip portion N in the vertical direction with respect to the sheet conveying direction a is defined as a C point. From the straight line connecting the point C and the center of gravity G of the flange 139, the points of intersection of the inner circumference restricting portion 139a and the lines rotated 45 ° upstream and downstream about the point G are the points D and E, respectively. And

  In this figure, the region from point A to point D is the upstream region (second region) X, the region from point D to point E is the top surface region (first region) Y, and the region from point E to point B is the downstream region Z. I decided to call it. The upstream region X and the downstream region Z are closer to the nip N than the top surface region Y with respect to the rotation direction of the film 133.

  A dotted line in FIG. 19 shows a rotation trajectory (broken line) of the film 133 that is rotated by the pressure roller 134 using the flange 139 in which the inner periphery restricting portion 139a has a substantially perfect circle shape. The film 133 receives a downstream conveying force from the pressure roller 134 at the nip portion N, and rotates while being biased to the downstream side. For this reason, the contact between the inner surface regulating surface 139f of the inner circumference regulating portion 139a and the film 133 is not uniform in every portion. Specifically, in the upstream region X, the top surface region Y, and the downstream region Z, since the contact between the film 133 and the inner surface regulating surface 139f changes, the roles required for each region are different.

  First, the contact between the film 133 and the inner surface regulating surface 139f in the top surface region Y is as described above. Since the inner periphery restricting portion 139a lifts the film 133, the film 133 and the inner surface restricting surface 139f are rubbed strongly. Therefore, it is necessary to reduce the wear of the film 133 and the inner periphery restricting portion 139a by optimizing the inclination angle θ of the inner restricting surface 139f.

  Next, the contact between the film 133 and the inner surface regulating surface 139f in the downstream region Z will be described. As described above, the film 133 rotates while being biased toward the downstream side, and the film 133 and the inner surface regulating surface 139f hardly contact each other. The inner periphery restricting portion on the downstream side of the flange 139 has a role of restricting the film 133 when the film 133 is rotated in reverse by jam processing in the fixing device 130. Therefore, the rubbing between the film 133 and the inner surface regulating surface 139f in the downstream region Z hardly occurs.

  Finally, the contact between the film 133 and the inner surface regulating surface 139f in the upstream region X will be described. As described above, the film 133 rotates while being biased toward the downstream side, and in the upstream region X, the film 133 rotates while following the inner surface regulating surface 139f. Therefore, also in the upstream region X, like the top surface region Y, the film 133 and the inner surface regulating surface 139f are actively rubbed. However, in the upstream region X, the inclination angle θ of the inner surface regulating surface 139f is preferably close to 0 °, and the reason will be described below.

  FIG. 20 is a view of the film 133 and the flange 139 as seen from the top side. Usually, a clearance α is provided between the film end and the end regulating surface 139b of the flange 139. This is to prevent the film 133 from stretching against the end regulating portion 139b when the length of the film itself is long, such as when the film 133 is thermally expanded. For this reason, during normal use, the film 133 may move to either the flange 139L or 139R due to the influence of the conveyance of the paper S or the like.

  FIG. 21 shows a state in which the film 133 is moved to one side when the length of the film itself is short and the clearance between the end portion restricting portion 139b of the flange 139 is large. (A) shows a case where the inclination angle of the inner surface regulating surface 139f in the upstream region is small, and (b) shows a case where the inclination angle is large.

  As described above, in the upstream region, the film 133 rotates while following the inner surface regulating surface 139f. When the film 133 approaches one side with a large inclination angle in the upstream region of the inner surface regulating surface 139f (in the case of (b)), the side opposite to the direction of the film 133 is received by the inclined inner portion. . As a result, the regulation on the inner surface regulating surfaces 139f at both ends of the film 133 is different on the left and right, and the film 133 rotates in an inclined state with respect to the rotation direction of the pressure roller 134 and the sheet conveyance direction a. .

  This state is not preferable in the following two points. The first is the stability of paper conveyance. Since the film 133 rotates in an oblique state with respect to the paper conveyance direction a, a force for conveying the paper S obliquely works. As a result, the paper S is inclined with respect to the image, and further develops a problem such as a conveyance jam.

  The second is the durability of the film 133. Since the film 133 is in an oblique state, the way of contact with the end restricting portion 139b is changed. When the film 133 is inclined as shown in (c), there is some clearance β between the upstream side and the end regulating part 139b, and the other part is strongly rubbed with the end regulating part 139b. become. In this case, a higher rubbing pressure is applied to the film 133 than in the case of hitting the entire circumference of the end portion regulation 139b, and the durability of the film 133 is lowered.

  From the above results, in the top surface region Y, there is an appropriate inclination angle of the inner surface regulating surface 139f because both the durability of the film 133 and the lifting effect of the film 133 are compatible. Specifically, it is desirable that the inclination angle of the inner surface regulating surface 139f of the top surface region Y is in the vicinity of 2 ° (2 ° or more). In the upstream region X, the inclination angle of the inner surface regulating surface 139f is preferably small from the viewpoint of the conveyance stability of the paper S and the durability of the film 133.

  For the upstream region X of the inner surface regulating surface 139f, the inclination angle may be 0 degree, that is, the distance between the inner surface regulating surface 139f and the inner surface of the film 133 may be the same over the longitudinal direction of the film 133.

  Specifically, it is desirable that the inclination angle of the inner surface regulating surface 139f of the upstream region X is set to around 0 °. That is, it is better that the inclination angle of the inner surface regulating surface 139f on the top surface area Y side is larger than the inclination angle of the upstream area X. Specifically, by increasing the inclination angle by 1 ° or more, the long life of the film can be achieved with a simple structure. Can be realized.

  In the present embodiment, the difference between the contact between the film 133 and the inner surface regulating surface 139f in the upstream region X and the top surface region Y is described using the parameter of the inclination angle with respect to the inner surface regulating surface 139f. A parameter called difference may be used.

  FIG. 22 is a view showing a state of the flange 139 when the inner surface regulating surface 139f of the top surface region Y is inclined. The farthest point on the inner surface regulating surface 139f when viewed from the generatrix passing through the center of gravity G is F point, Let H be the closest point. At this time, if the distance between the point F and the bus bar Q is f, and the distance between the point H and the bus line Q is h, the height difference between the point F and the point H as an index representing the inclination of the inner surface regulating surface 139f, that is, It can be expressed using fh.

  According to the present embodiment, by providing an appropriate height difference in the top surface area Y, it is possible to achieve both the durability of the film 133 and the lifting effect of the film 133, and by reducing the height difference as much as possible in the upstream area X, the film Both the durability of 133 and the conveyance stability can be achieved. Specifically, when the length of the inner surface regulating surface 139f is 5 mm, it is desirable that the height difference of the inclination of the top surface area Y is 0.15 mm or more, which is 0.08 mm larger than the height difference of the upstream area X. Thus, the life of the film 133 can be extended with a simple configuration.

  Further, in this embodiment, the boundary between the upstream region X and the top surface region Y, and the downstream region Z and the top surface region Y are set to the points D and E which are 45 ° upstream and downstream from the point C. However, since the contact with the film 133 varies depending on the shape of the inner surface regulating surface 139f of the flange 139, the position of the boundary may be changed according to the degree of contact.

  The configuration of the inner circumference regulating portion (inner surface regulating member) 139a is summarized as follows. The inner surface regulating surface (contact region) 139f of the inner circumference regulating portion 139a is inclined with respect to the bus bar Q of the film 133 so that the outer diameter becomes smaller toward the inner side in the longitudinal direction of the film (first rotating body) 133). Have. The inclination of the top surface area Y including the point C farthest from the nip portion N in the circumferential direction of the contact area is the upstream between the upstream end point A and the top surface area Y in the paper transport direction a in the circumferential direction of the contact area. Greater than the slope of region X.

  The inclination of the inner surface regulating surface 139f is the height difference (f−h) between the highest portion F and the lower portion H of the inner surface regulating surface, and the height difference of the top surface region Y is larger than the height difference of the upstream region X. The height difference of the top surface area Y is 0.15 mm or more. The difference between the height difference of the top surface area Y and the height difference of the upstream area X is 0.08 mm or more.

Example 2
In Example 1, by providing an inclination in the top surface area Y of the inner surface regulating surface 139f, local rubbing between the film 133 and the inner circumference regulating portion 139a is prevented, and the life of the film 133 can be extended. However, since the inner surface regulating surface 139f is provided with an inclination, the effect of lifting the film 139 is considerably reduced, and it may be difficult to further increase the number of built-in objects.

  In the second embodiment, the shape of the top surface region Y of the inner surface regulating surface 139f of the flange 139 is optimized to further balance the durability of the film 133 and the lifting effect. The basic configurations of the image forming apparatus 100 and the fixing device 130 in the second embodiment are the same as those in the first embodiment. The same numbers are assigned to the same components, and descriptions thereof are omitted.

  FIG. 23 is a view of the film 133 and the flange 139 as seen from the front. (A) shows a case where the inner surface regulating surface 139f of the flange 139 is not inclined, and as described with reference to FIG. 11, there is a problem of wear on the inner surface of the film at the innermost point J of the inner circumferential regulating portion 139a. It becomes. (B) is a state in which the inner surface regulating surface 139f is inclined as described in Example 1 (FIG. 14), and although the film inner surface wear is suppressed, the lifting effect of the film 133 compared to (a) is shown. Has decreased.

  In response to such a background, the flange 139 of the second embodiment is not inclined at the outer portion near the end portion of the inner surface regulating surface 139f, and obtains a conventional film fishing effect. The inner side of the inner surface regulating surface 139f is provided with a predetermined inclination to suppress inner surface wear of the film 133.

  FIG. 24 shows the height difference of the inner surface regulating surface 139f when an inclination of 2.5 ° is provided in all of the 5 mm length region of the inner surface regulating surface 139f. When the slope is provided, the inner side is lowered by about 175 μm compared to the case where there is no slope, indicating that the effect of lifting the film 133 is reduced by this amount.

  FIG. 25 shows an example of the flange 139 according to the second embodiment. Of the 5 mm length region of the inner surface regulating surface 139f, the inner 1 mm portion has an inclined region V1 that is inclined at an angle of 2.0 °, and the outer arc 4 mm is connected by a large arc R = 300. And a region V2.

  First, in terms of the lifting effect of the film 133, the height difference of the inner surface regulating surface 139f of the flange 139 is 47 μm, which is more effective than when all the inner surface regulating surfaces are inclined (FIGS. 23B and 24). Is expensive. Here, the height difference of the inner surface regulating surface 139f varies depending on which region of the inner surface regulating surface 5mm is the inclined region V1.

  Table 3 shows the height difference between the width of the inclined region V1 and the inner surface regulating surface 139f. Since the height difference of the inner surface regulating surface 139f becomes larger as the length of the inclined region V1 is longer, the lifting effect of the film 133 becomes smaller.

  Next, from the viewpoint that the inner surface of the film is scraped at the innermost point J of the inner surface regulating surface 139f of the flange 139, an inclined region V1 of 2.0 ° is provided on the inner surface regulating surface 139f. Therefore, it is more advantageous than the configuration in which the inner surface regulating surface 139f is not inclined ((a) of FIG. 23). On the other hand, when the angle changes steeply at the joint W between the inclined region V1 and the arc region V2, the inner surface of the film may be scraped off at this portion.

  The following two elements exist regarding the wear of the inner surface of the film at the joint portion W. The first is the shape of the outer region than the inclined region V1. FIG. 26 is a diagram of the flange when the inner inclined region V1 and the outer straight region V2 having an inclination angle of 0 ° are connected by a small R arc region V3. In this case, since the radius R of the arc region V3 is small, the inner surface wear of the film 139 is promoted at the joint portion W. In the second embodiment, all the outer region V2 (FIG. 25) is a large arc of R = 300, and the change in the angle of the connecting portion W is reduced.

  The second is the width of the inclined region V1. The joint portion W with the outer region V2 moves to the inner side as the width of the inclined region V1 is smaller, and to the outer side as the width is wider. The contact between the film 133 and the inner surface regulating surface 139f changes depending on the deflection of the film 133 and the positional relationship between the joints W, and the state of inner surface wear of the film 133 changes. In this case, the narrower the inclined region V1, the closer to the case where the inner surface regulating surface 139f is not inclined, and the inner surface of the film 133 is easily worn.

  In Example 2, the outer region V2 is connected in an arc shape, and the inclined region V1 is narrowed to such an extent that the inner surface wear of the film 133 does not occur, thereby increasing the fishing effect of the film 133.

  In the following, experiments were conducted to confirm these effects.

<Experiment 3>
The amount of wear on the inner surface of the film when the length of the inclined region V1 of the inner surface regulating surface 139f was changed was examined. The same image forming apparatus main body as in Experiment 1 was used. Regarding the fixing device, the angle of the inclined region V1 of the inner surface regulating surface 139f was set to 2.5 °, and the length of the inclined region V1 was prepared in nine increments of 0.5 mm between 0 to 4 mm.

  Next, using this image forming apparatus main body and the fixing device, printing was performed for about 100 hours, and the amount of wear on the inner surface of the film at the portion rubbed against the flange 139 at that time was compared.

  The experimental results are shown in Table 4 and FIG. As the length of the inclined region V1 becomes longer, the joint W portion moves to the outside of the inner surface regulating surface 139f, and the friction with the inner surface of the film becomes weak, so the amount of wear is reduced. The amount of wear on the inner surface of the film is desirably up to about 10 μm, and the length of the inclined region V1 of the inner surface regulating surface 139f is desirably 2.0 mm or more. The height difference of the inner surface regulating surface 139f at this time was 79 μm, which was smaller than the height difference of 175 μm in Example 1.

  From the above results, the inner surface regulating surface 139f has an inner region V1 with a slope, and the outer region V2 has a flange 139 that is connected by a circular arc, so that the difference in height of the inner surface regulating surface can be made smaller than before. However, the durability of the film 133 can be increased. Further, it has been confirmed that the same effect can be obtained even when the arc shape is used to connect the inner surface regulating surface 139f of the second embodiment.

  In this way, by providing an inclination to the inner surface regulating surface 139f that lifts up the film 133, the frictional pressure between the film 133 and the inner surface regulating surface 139f becomes uniform, and the wear rate of the inner surface of the film is reduced. By reducing the inclination of the inner surface regulating surface 139f on the upstream side, the film 133 is not rotated obliquely, and stable paper conveyance is possible. By adopting such a configuration, it is possible to extend the life of the film 133 with a simple configuration.

《Other matters》
An appropriate range of the inclination angle, the height difference, and the length of the inclined area of the inner surface regulating surface of the flange in Examples 1 and 2 may vary depending on the material and thickness of the film. The present Examples 1 and 2 have the above-described characteristic configuration, and thus have an effect of suppressing wear caused by sliding with the flange on any film. The inner surface regulating surface of the flange is inclined so as to move away from the inner surface of the film toward the longitudinal center of the film with respect to the longitudinal direction of the film. The configuration is larger than the downstream region.

  (1) The pressure configuration of the film unit 150 and the pressure roller 134 for forming the nip portion N may be a device configuration that presses the pressure roller 134 against the film unit 150. It is also possible to construct a structure that presses both the film unit 150 and the pressure roller 134 together. That is, the pressure mechanism may be configured to press at least one of the film unit 150 and the pressure roller 134 toward the other.

  (2) The sliding member (backup member) inside the film 133 may be a member other than the heater 132.

  (3) The heating means for the film 133 is not limited to the heater 132 of the embodiment. An appropriate heating configuration such as an internal heating configuration, an external heating configuration, a contact heating configuration, or a non-contact heating configuration using other heating means such as a halogen heater or an electromagnetic induction coil can be adopted.

  (4) In the embodiment, the image heating apparatus has been described by taking a fixing apparatus that heats and fixes an unfixed toner image formed on a recording material as an example, but is not limited thereto. The present invention can also be applied to an apparatus (glossiness improving apparatus) that increases the gloss (glossiness) of an image by reheating a toner image fixed or assumed on the recording material.

  DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 130 ... Fixing apparatus (image heating apparatus), 150 ... Film unit, 131 ... Guide member, 132 ... Heater, 133 ... Film (1st rotary body), 134 ... Pressure roller (2nd) Rotating body), 138, thermistor, 139, flange, 139a, inner surface regulating member, N, nip, S, recording material

Claims (9)

A tubular film,
A contact member that contacts the inner surface of the film;
A nip portion forming member that forms a nip portion together with the contact member via the film, wherein the recording material on which the image is formed is heated while being conveyed, and the image is fixed to the recording material;
A regulating member provided at a longitudinal end portion of the film and having an inner surface regulating surface facing the inner surface of the film and regulating the position of the inner surface of the film;
The inner surface regulating surface, when viewed in the longitudinal direction of the film, with respect to the rotation direction of the film, a first region farthest from the nip portion and a second region closer to the nip portion than the first region And having
The first region and the second region are inclined away from the inner surface of the film toward the longitudinal center of the film with respect to the longitudinal direction of the film. Is greater than the tilt angle of the second region,
An image heating apparatus.   2. The image heating apparatus according to claim 1, wherein the second region is located upstream of the center of the nip portion in the recording material conveyance direction.   The regulating member has an end regulating surface that contacts the longitudinal end surface of the film and regulates movement of the film in the longitudinal direction when the film moves in the longitudinal direction of the film, and the end regulating surface is The image heating apparatus according to claim 1, wherein the image heating apparatus is provided outside the inner surface regulating surface with respect to a longitudinal direction of the film.   The image heating apparatus according to claim 1, wherein an inclination angle of the first region is 1.5 degrees or more.   The image heating apparatus according to claim 1, wherein the contact member is a heater. A tubular film,
A contact member that contacts the inner surface of the film;
A nip portion forming member that forms a nip portion together with the contact member via the film, wherein the recording material on which the image is formed is heated while being conveyed, and the image is fixed to the recording material;
A regulating member provided at a longitudinal end portion of the film and having an inner surface regulating surface facing the inner surface of the film and regulating the position of the inner surface of the film;
The inner surface regulating surface, when viewed in the longitudinal direction of the film, with respect to the rotation direction of the film, a first region farthest from the nip portion and a second region closer to the nip portion than the first region And having
The first region is inclined so as to be away from the inner surface of the film as it goes toward the longitudinal center of the film with respect to the longitudinal direction of the film, and the second region extends over the longitudinal direction of the film. The distance to the inner surface of
An image heating apparatus.   The regulating member has an end regulating surface that contacts the longitudinal end surface of the film and regulates movement of the film in the longitudinal direction when the film moves in the longitudinal direction of the film, and the end regulating surface is The image heating apparatus according to claim 6, wherein the image heating apparatus is provided outside the inner surface regulating surface with respect to a longitudinal direction of the film.   The image heating apparatus according to claim 6, wherein an inclination angle of the first region is 1.5 degrees or more.   The image heating apparatus according to claim 6, wherein the contact member is a heater.