JP2019117357A - Fixation device - Google Patents

Abstract

To reduce damage to be affected by a fixing film.SOLUTION: In a fixation device including: a cylindrical film; and a regulation unit that, when the film moves in a rotary axial direction of a roller, has a first surface contacting with a longitudinal end surface of the film and regulating a movement of the film, and a second surface serving a surface guiding an interior peripheral surface of the film, the regulation unit is configured so as to be capable of inclinedly moving between a first position parallel with the longitudinal end surface of the film and a second position apart from the first position as the first surface heads for a downstream side regarding a conveyance direction. While the regulation unit inclinedly moves from the first position to the second position, force generates that inclinedly moves in a direction where the regulation unit heads for the first position from the second position, and the force in an area on a downstream side in the conveyance direction of the regulation unit is configured so as to be smaller than that in an area on an upper stream side therein.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fixing device mounted on an electrophotographic image forming apparatus.

  As a fixing device mounted on an electrophotographic image forming apparatus such as a laser beam printer and a copying machine, a fixing device of a film heating type which is excellent in energy saving performance and has a short warm-up time is known. The fixing device of the film heating system includes a cylindrical fixing film, a heater contacting the inner surface of the fixing film, and a pressure roller forming a nip with the heater via the fixing film. The recording material carrying the toner image at the nip portion is heated while being nipped and conveyed, and the toner image is fixed on the recording material. In addition, in the same type of fixing device, a fixing flange having a control surface in contact with the longitudinal end of the fixing film and a guide surface for guiding the smooth rotation of the fixing film is provided at the longitudinal end of the fixing film. Will be installed.

  In this fixing device, a shift force for moving the fixing film in the rotational axis direction of the pressure roller may act on the fixing film. The causes of the shift force of the fixing film include misalignment between the fixing film and the pressure roller, and a difference in pressing force at both longitudinal ends of the nip portion. Due to this shift force, the fixing film may be broken when the longitudinal end surface of the fixing film contacts the regulating surface of the fixing flange with high pressure.

  Therefore, when the fixing film is moved in the longitudinal direction by the shift force, the projection provided on the control surface of the fixing flange contacts the longitudinal end surface of the fixing film, changing the posture of the fixing film, and the shift force in the opposite direction. Has been disclosed (Patent Document 1). With this structure, it is possible to reduce the damage that the longitudinal end of the fixing film receives due to the shift force.

Japanese Patent Application Publication No. 2007-25473

  However, according to the configuration of Patent Document 1, pressure is applied locally to the longitudinal end of the fixing film in the period from when the longitudinal end face of the fixing film comes in contact with the protrusion of the regulating surface of the fixing flange until the posture of the fixing film changes. May get damaged and receive damage.

  A side surface of the present invention is a roller which contacts a cylindrical film, an inner surface of the film, and a nip forming member long in the longitudinal direction of the film and the nip forming member via the film. A surface which is provided at the longitudinal end of the film and which contacts the longitudinal end surface of the film when the film moves in the rotational axis direction of the roller and restricts the movement of the film, and the direction of rotation of the film With respect to the first surface provided from the upstream side to the downstream side of the recording material conveyance direction of the nip portion, and a surface for guiding the inner peripheral surface of the film, along the inner peripheral surface of the film A fixing unit having a control portion having a second surface which is a peripheral surface, and heating the recording material on which the image is formed in the nip while conveying it to fix the image on the recording material; , When the restriction portion is viewed in a direction perpendicular to both the rotational axis direction of the roller and the transport direction, at least the first surface is parallel to the rotational axis direction of the film. A first position parallel to the longitudinal end face of the film in one case, and a longitudinal direction of the film parallel to the rotation axis direction as the first surface is moved downstream with respect to the transport direction It is configured to be capable of tilting between a second position away from the longitudinal end face of the film, and while the restricting portion tilts from the first position to the second position, the restricting portion is movable. A force is generated that tilts in a direction from the second position toward the first position, and the force is configured such that a region on the downstream side of the transport direction of the restricting portion is smaller than a region on the upstream side It is characterized by

  According to the present invention, it is possible to reduce the damage that the fixing film receives due to the shift of the fixing film.

FIG. 1 is a cross-sectional view of an image forming apparatus according to a first embodiment. (A) A view of the fixing device according to the first embodiment as viewed in the conveyance direction of the recording paper, (b) a view of the fixing device according to the first embodiment as viewed from above the conveyance surface of the recording paper, (c) (a) It is sectional drawing of AA '. (A) Front view of the fixing flange which concerns on Example 1, (b) The side view of the fixing flange which concerns on Example 1, (c) The top view of the fixing flange which concerns on Example 1. FIG. (A) It is a figure which shows the state of the fixing flange before the fixing flange which concerns on Example 1 at the time of receiving the offset force of a fixing film inclining. (B) It is a figure which shows the state of the fixing flange after the fixing flange which concerns on Example 1 at the time of receiving the offset force of a fixing film inclining. (A) It is a figure which shows the state of the fixing flange before the fixing flange which concerns on Example 2 at the time of receiving the offset force of a fixing film inclining. (B) It is a figure which shows the state of the fixing flange after the fixing flange which concerns on Example 2 at the time of receiving the shift | offset | difference force of a fixing film.

Example 1
(1) Description of Image Forming Apparatus FIG. 1 is a schematic block diagram of an example of an image forming apparatus on which the fixing device according to the present invention can be mounted.

  The image forming apparatus 100 includes a sheet feeding unit 102, an image forming unit 104 (a laser scanner unit 103, a photosensitive drum 110, a developing roller 109, and a transfer roller 111), and a fixing device 105.

  When image information is transferred from the external apparatus to the image forming apparatus, the sheet feeding unit 102 of the image forming apparatus separates and feeds the recording sheets P one by one from the sheet feeding tray 107. The recording paper P delivered from the paper feed tray 107 is conveyed to the image forming unit 104 by a contact portion (conveyance nip portion) between a conveyance roller and a conveyance roller installed opposite to the conveyance roller. Similarly, the photosensitive drum 110 rotatably supported in the image forming unit 104 is uniformly charged by the rotatable charging roller 108, and the laser light emitted from the laser optical system 103 based on the image information. A latent image is formed by L. The photosensitive drum 110 rotates in a position opposite to the developing sleeve 109 carrying the toner, passes a bias, and is applied to a charged area on the surface of the photosensitive drum 110 by a bias applied between the photosensitive drum 110 and the developing sleeve 109. Toner is applied to form a toner image.

  When the toner image formed on the photosensitive drum 110 passes the contact portion (transfer nip portion) between the photosensitive drum 110 and the transfer roller 111 as the photosensitive drum 110 rotates, the photosensitive drum 110 and the transfer roller 111 The image is transferred onto the recording paper P by the transfer bias applied during the period. The toner image carried on the recording paper P becomes a fixed image by the supply of heat and the application of pressure in the fixing device 105.

(2) Description of Fixing Device Configuration Next, the fixing device 105 will be described in detail with reference to FIGS. FIG. 2A is a view of the fixing device 105 according to the present embodiment as viewed from the upstream side in the recording sheet conveyance direction, and FIG. 2B is a conveyance surface of the recording paper according to the present embodiment. Against the upper side. In FIGS. 2A and 2B, the fixing film 114 is shown by a dotted line so that the inside of the fixing device 105 can be seen. Moreover, FIG.2 (c) is sectional drawing in AA 'shown to Fig.2 (a).

  In FIG. 2, a heater 112 as a nip portion forming member is in contact with the inner surface of the fixing film 114. The heater 112 has a substrate formed of ceramic or the like, and a heating resistor formed on the substrate. A surface of the heater 112 opposite to the surface in contact with the fixing film 114 is supported by a support 115. Further, the support 115 is supported by an iron stay 116 in order to compensate for its strength. A flexible cylindrical fixing film 114 is provided around them, and fixing flanges 1201 L and 1201 R are provided at both ends of the fixing film 114.

  The fixing flanges 1201L and 1201R are fitted to the support 115 and the stay 116, and are pressed by the spring S toward the pressure roller 117. Thus, the heater 112 forms the fixing nip N together with the pressure roller 117 via the fixing film 114.

  When the pressure roller 117 is driven in the direction of arrow R1 in the figure, the fixing film 114 receives power from the pressure roller 117 at the fixing nip N, and is driven to rotate in the direction of arrow R2.

  The heater 112 applies heat to the fixing film 114 while being temperature-controlled by the thermistor 113 shown in FIG. The heat of the fixing film 114 heated by the heater 112 is transferred to the pressure roller 117 at the fixing nip N, and the pressure roller 117 is also heated. When the recording paper P to which the unfixed toner image is transferred is conveyed to the fixing nip N, the heat of the fixing film 114 and the pressure roller 117 heated at the fixing nip N is transmitted to the recording paper P and the toner image, and the recording paper The toner image is fixed to P.

(Pressing roller)
The pressure roller 117 has a cored bar 117a, an elastic layer 117b formed on the outer side of the cored bar 117a, and a release layer 117c formed on the outer side of the elastic layer 117b. The cored bar 117a is formed of a metal such as SUS. The elastic layer 117 b is formed of heat-resistant silicone rubber or foam rubber. The release layer 117c is formed of a fluorine resin such as PFA, PTFE, or FEP. The pressure roller 117 is rotatably supported by a bearing (not shown). Further, when the drive gear G provided at the end of the cored bar 117a of the pressure roller 117 is rotationally driven by a motor (not shown), the pressure roller 117 rotates in the direction of the arrow R1 in FIG.

(Fixing film)
The fixing film 114 has a base layer 114a, a release layer 114c formed on the outer side of the base layer 114a, and a primer layer 114c for bonding the base layer 114a and the release layer 114c. The base layer 114a is formed of a polyimide resin to which a filler or the like is added in order to improve the thermal conductivity and the strength. The release layer 114c is formed of a fluorine resin such as PFA, PTFE, or FEP.

  In the present embodiment, in order to cope with speeding up and energy saving, the thickness of the base layer 114 a is made as thin as possible so that the heat of the heater 112 can be easily transmitted to the surface of the fixing roller 117. However, the thickness of the base layer 114 a is preferably 30 to 70 μm because the strength is too low if the base layer 114 a is too thin. In this example, the thickness of 60 μm was used.

(Fixing flange)
The fixing flanges 1201L and 1201R, which are the features of this embodiment, will be described with reference to FIG. Since fixing flanges 1201L and 1201R have a shape that is plane-symmetrical to an imaginary plane passing through the longitudinal center of pressure roller 117 and perpendicular to the rotational axis direction, only fixing flange 1201R will be described.

  FIG. 3 is a view showing the shape of the fixing flange 1201R. FIG. 3A is a front view of the pressure roller 117 as viewed from the rotational axis direction, and FIG. 3B is a side view of the recording sheet P as viewed from the upstream side in the conveyance direction. 3C is a top view of the fixing flange 1201R in FIG. 3A as viewed from above the conveyance surface of the recording paper P. As shown in FIG.

  Hereinafter, the rotation axis direction of the pressure roller 117 is simply referred to as “rotation axis direction”. Further, “viewing from above the conveyance surface of the recording material” is synonymous with “viewing in a direction perpendicular to both the rotation axis direction and the conveyance direction of the recording material”.

  As shown in FIG. 3C, the fixing flange 1201R includes a restricting portion 1201Rab and a support portion 1201Rx. The restricting portion 1201 Rab has a restricting surface 1201 Rb (first surface) and a guide surface 1201 Ra (second surface), and is connected to the support portion 1201 Rx via the connecting portion 1201 Rxy. As shown in FIG. 3C, a connection portion 1201Rxy is provided on the upstream side in the recording material conveyance direction between the regulation portion 1201Rab and the support portion 1201Rx, and a gap 1201Ry is provided on the downstream side of the connection portion 1201Rx. It is provided. That is, the restricting portion 1201 Rab is configured to tilt with respect to the supporting portion 1201 Rx with the upstream end of the recording material in the conveyance direction fixed to the connection portion 1201 Rxy and the downstream end of the recording material in the conveyance direction as the free end. It is done. In addition, the support portion 1201Rx has a role of contacting the restricting portion 1201 Rab when the amount of tilting of the restricting portion 1201 Rab is large, and regulating the amount of tilting.

  The guide surface 1201Ra is a circumferential surface along the inner circumferential surface of the fixing film 114, and is a surface that guides the inner circumferential surface of the fixing film 114 when the fixing film 114 rotates. The restricting surface 1201 Rb is a surface that contacts the longitudinal end surface of the fixing film 114 when the fixing film 114 moves in the rotation axis direction, and restricts the movement of the fixing film 114 in the rotation axis direction. As illustrated in FIG. 3A, the restriction surface 1201Rb is a surface provided from the upstream side to the downstream side of the fixing nip portion N in the conveyance direction of the recording material with respect to the rotation direction of the fixing film 114.

  Since the gap 1201Ry is provided, when the regulating surface 1201Rb is pressed by the longitudinal end face of the fixing film 114, the downstream side of the recording paper conveyance direction is more easily retracted in the longitudinal direction of the fixing film than the upstream side. . Although described later, the posture of the fixing film can be changed by the tilting of the fixing flange restricting surface 1201Rb, and the shift direction of the fixing film 114 can be reversed. The width H of the gap 1201 Ry is preferably 0.3 mm to 2 mm in consideration of the inclination of the fixing film 114. In the present embodiment, the width H of the gap 1201Ry is 1.0 mm.

  Further, as a material used for the fixing flange 1201R, it is desirable to use a resin having both heat resistance and elasticity so that the gap 1201Ry can be deformed. In this example, integral molding of polyetheretherketone (PEEK) was employed. PEEK is a plastic resin and is easy to mold. Note that only the support portion 1201Rx having the gap 1201Ry may be PEEK.

(3) Effects of Inclination of the Regulating Surface of the Fixing Flange Referring to FIG. 4, when the fixing film 114 contacts and stresses the fixing flange 1201 R of the present embodiment by the shift force, The tilting will be described. Since the fixing flange is laterally symmetrical with respect to a virtual plane passing through the longitudinal center of the fixing roller 117 and perpendicular to the rotational axis direction, the description of the tilting of the fixing flange 1201L is omitted. In FIG. 4, descriptions of other components are omitted so that the relationship between the inclination of the fixing film 114 with respect to the fixing nip center line Na and the inclination of the fixing flange 1201R can be easily understood. Further, the gap 1201Ry is exaggerated for clarity. Further, the fixing nip center line Na is parallel to the rotation axis direction.

  When the fixing film 114 receives a biasing force toward the fixing flange 1201R, as in the fixing film 114 drawn by a solid line in FIG. 4A, the longitudinal direction (the generatrix direction) of the fixing film 114 is the center of the fixing nip. It is a case where it has angle alpha to line Na. Assuming that the driving force of the pressure roller 117 is F, the shift force is represented by F sin α. By this shift force, the longitudinal end surface of the fixing film 114 pushes in the control surface 1201 Rb of the fixing flange.

  When the fixing film 114 is not in contact with the fixing flange 1201Rb, the restricting surface 1201Rb is at the first position, as in the fixing film 114 drawn by the two-dot chain line in FIG. 4A. In the first position, when viewed from above the conveyance surface of the recording material, the restriction surface 1201 Rb is a length of the fixing film 114 (two-dot chain line) in the case where the longitudinal direction of the fixing film 114 is parallel to the rotation axis direction. It is a position parallel to the end face. When the regulating surface 1201Rb is further pushed from the first position by the longitudinal end face of the fixing film 114, the amount by which the downstream side of the regulating surface 1201Rb in the conveyance direction of the recording sheet moves in the rotational axis direction becomes larger than the upstream side. That is, as shown in FIG. 4B, when viewed from above the conveyance surface of the recording material, the regulation member 1201 Rab tilts in the arrow V direction with the 1201 Rxy portion as a fulcrum, and reaches the second position. In this second position, the longitudinal end face of the fixing film 114 (two-dot chain line) in the case where the longitudinal direction of the fixing film 114 is parallel to the rotation axis direction as the regulating surface 1201Rb goes to the downstream side of the recording material conveyance direction. And the inclined position so that the distance with it becomes long.

  When the longitudinal end face of the fixing film 114 contacts, the regulating portion 1201 Rab gradually tilts together with the fixing film 114 from the first position to the second position described above. Therefore, the longitudinal end surface of the fixing film 114 is unlikely to receive a local reaction force from the control surface 1201 Rb. While the regulating portion 220 Rab tilts from the first position to the second position, a restoring force in the direction of tilting from the second position to the first position acts on the regulating portion 220 Rab.

  On the other hand, while the fixing film 114 is driven to rotate, the inner surface of the fixing film 114 which is guided by the guide surface 1201Ra is the guide on the upstream side in the recording material conveyance direction in FIGS. It is only the region facing the region (Sr) of the surface 1201Ra. That is, the downstream side of the conveyance direction of the recording material in the inner surface of the fixing film 114 is not guided by the guide surface 1201Ra. Therefore, if the longitudinal end surface of the fixing film 114 makes strong contact with the control surface 1201 Rb on the downstream side in the recording material conveyance direction, that portion may be buckled. As described above, in the control surface 1201 Rb of the present embodiment, the downstream side of the recording material conveyance direction is easily retracted to the outside, so the longitudinal end surface of the fixing film 114 is the restriction surface at the downstream side of the recording material conveyance direction. Strong contact with 1201 Rb can be suppressed.

  Further, when the restricting surface 1201 Rb is tilted to the second position, the longitudinal direction of the fixing film 114 is opposite to the angle α with respect to the fixing nip center line Na as the fixing film 114 of the solid line shown in FIG. Orientation angle β. Therefore, the direction of the rotational force and the shift force of the fixing film 114, which is a component of the driving force F of the pressure roller 117, changes, and the shift force is reverse to that of the above. Therefore, the fixing film 114 is shifted in the opposite direction as before. That is, the fixing flange 1201R of the present embodiment can prevent the fixing film 114 from being subjected to a strong offset force in only one direction.

  In the fixing flange 1201R of the present embodiment, the guide surface 1201Ra is also inclined in the same manner as the restriction surface 1201Rb. Along with the tilting of the restricting surface 1201 Rb, the upstream tip end 1201 Raa of the guide surface 1201 Ra also tilts and moves away from the inner circumferential surface of the fixing film 114. Therefore, it is possible to suppress that the upstream leading end portion 1201Raa of the guide surface 1201R bites into the inner circumferential surface of the fixing film 114 and damages the fixing film 114.

  According to the present embodiment, the longitudinal end face of the fixing film 114 is prevented from receiving a local reaction force, and there is an effect of preventing the fixing force of the fixing film 114 from being continued to be applied in only one direction. In addition to this, since the upstream tip end portion 1201 Raa of the guide surface of the fixing flange is difficult to contact locally with the inner surface of the fixing film 114, there is an effect of suppressing the abrasion of the inner surface.

  In the present embodiment, the first position of the restricting portion is a position parallel to the longitudinal end surface of the fixing film in the case where the longitudinal direction of the fixing film is parallel to the rotation axis direction, but is not limited thereto. The first position of the restricting portion may be a position where the restricting surface has an inclination opposite to the second position of the present embodiment or a position inclined in the same direction as the second position.

Example 2
Example 2 will be described. The parts configurations and operations other than the fixing flange are the same as in the first embodiment, and therefore the description thereof is omitted.

(1) Fixing Flange The fixing flange 220R of the present embodiment will be described with reference to FIG. As in the first embodiment, the fixing flange passes the longitudinal center of the pressure roller 117 and has a plane-symmetrical shape with respect to a virtual surface perpendicular to the rotation axis direction. Therefore, only the fixing flange 220R will be described.

  FIG. 5 is a view of the fixing flange 220R and the fixing film 114 as viewed from above the conveyance surface of the recording sheet. The fixing flange 220R includes a restricting portion 220Rab having a restricting surface 220Rb (first surface) and a guide surface 220Ra (second surface), and a support portion 220Rss that tiltably supports the restricting portion 220ab. . Further, the restriction portion 220ab and the support portion 220Rss are connected by an elastic member 220 Rek (second elastic member) and an elastic member 220 Reu (first elastic member).

  Similar to the guide surface 1201Ra in the first embodiment, the guide surface 220Ra is a circumferential surface along the inner circumferential surface of the fixing film 114, and guides the inner circumferential surface of the fixing film 114 when the fixing film 114 rotates. It is a face. The restricting surface 220Rb is a surface that contacts the longitudinal end surface of the fixing film 114 when the fixing film 114 moves in the rotation axis direction, and restricts the movement of the fixing film 114 in the rotation axis direction. The restriction surface 220Rb is a surface provided from the upstream side to the downstream side of the fixing nip portion N in the conveyance direction of the recording material with respect to the rotation direction of the fixing film 114. In the present embodiment, the guide surface 220Ra is formed to be perpendicular to the control surface 220Rb at an arbitrary position of the control surface 220Rb.

  The elastic members 220 Reu and 220 Rek are provided to tilt the regulating portion 220 ab when the longitudinal end face of the fixing film 114 contacts and the regulating surface 220 Rb is pressed. Compression springs, rubber, etc. are used as the elastic members 220 Reu and 220 Rek, and in this embodiment, compression springs are used. When viewed from above the conveyance surface of the recording material, the elastic members 220 Reu and 220 ek are respectively upstream and downstream of the fixing nip center line Na with respect to the conveyance direction of the recording material.

  As in the first embodiment, when viewed from above the conveyance surface of the recording material, the first restriction surface 220Rb is not in contact with the restriction surface 220Rb as in the fixing film 114 of the two-dot chain line in FIG. In the position of. In the first position, when viewed from above the conveyance surface of the recording material, the restriction surface 1201 Rb is a length of the fixing film 114 (two-dot chain line) in the case where the longitudinal direction of the fixing film 114 is parallel to the rotation axis direction. It is a position parallel to the end face.

  The spring 220 Rek on the downstream side in the conveyance direction of the recording material has a lower spring constant than the spring 220 Reu on the upstream side. That is, the spring 220 Rek on the downstream side in the conveyance direction of the recording material has a smaller elastic force than the spring 220 Reu on the upstream side. Of the restriction surface 220Rb, the downstream side in the conveyance direction of the recording paper is more likely to move to the outer side in the rotation axis direction (the direction of the arrow V in FIG. 5B) than the upstream side. Therefore, as shown by a solid fixing film 114 shown in FIG. 5B, when the control surface 220Rb is pressed by a long force by the longitudinal end surface of the fixing film 114, as viewed from above the conveyance surface of the recording material, become. The restricting portion 220 Rab is the same as the end surface of the fixing film 114 (two-dot chain line) in the case where the longitudinal direction of the fixing film 114 is parallel to the rotation axis direction as the restricting surface 220 Rb goes to the downstream side of the recording material conveyance direction. Move to a second position that is inclined so as to increase the distance. As in the first embodiment, when the longitudinal end face of the fixing film 114 contacts, the restricting portion 220 Rab gradually tilts together with the fixing film 114 from the first position to the second position described above. Therefore, the longitudinal end face of the fixing film 114 is unlikely to receive a local reaction force from the regulating surface 220Rb.

  Further, while the fixing film 114 is rotationally driven, the inner surface of the fixing film 114 which is guided by the guide surface 220Ra is a guide on the upstream side in the conveyance direction of the recording material in FIGS. 5A and 5B. It is only a region facing the region (Sr) of the surface 220Ra. That is, the downstream side of the conveyance direction of the recording material in the inner surface of the fixing film 114 is not guided by the guide surface 220Ra. Therefore, if the longitudinal end surface of the fixing film 114 makes strong contact with the restricting surface 220Rb on the downstream side in the recording material conveyance direction, that portion may be buckled. In this embodiment, the spring 220 Rek on the downstream side in the recording material conveyance direction has a smaller spring constant than the upstream spring 220 Reu. Therefore, since the downstream side of the control surface 220Rb in the conveyance direction of the recording material is easily retracted to the outside, the longitudinal end surface of the fixing film 114 can be prevented from strongly contacting the control surface 220Rb.

  When the restricting surface 220Rb is tilted to the second position, the longitudinal direction of the fixing film 114 is opposite to the angle α with respect to the fixing nip center line Na, as in the fixing film 114 shown by a solid line in FIG. Have an angle β of Therefore, the direction of the rotational force and the shift force of the fixing film 114, which is a component of the driving force F of the pressure roller 117, changes, and the shift force is reverse to that of the above. Therefore, the fixing film 114 is shifted in the opposite direction as before. That is, the fixing flange 220R of the present embodiment can prevent the fixing film 114 from being subjected to a strong offset force in only one direction.

  Furthermore, the guide surface 220Ra is also inclined in the same manner as the control surface 220Rb. Therefore, as in the first embodiment, while the posture of the fixing film 114 changes to follow the inclination of the regulating surface 220Rb, it is possible to prevent the upstream tip portion 220Raa of the guide surface 220Ra from biting into the inner circumferential surface of the fixing film 114. .

  In the configuration of the second embodiment, the inclination of the restricting surface 220Rb can be set with higher precision than in the first embodiment by adjusting the spring constants of the elastic members 220 Reu and 220 Rek.

  According to this embodiment, it is possible to prevent the longitudinal force of the fixing film 114 from being subjected to the local reaction force, and to prevent the fixing force of the fixing film 114 from being continuously applied in only one direction. In addition to this, the upstream tip end portion of the guide surface of the fixing flange is difficult to contact locally with the inner surface of the fixing film, so that there is an effect of suppressing the abrasion of the inner surface.

  In the present embodiment, the first position of the restricting portion is a position parallel to the longitudinal end surface of the fixing film in the case where the longitudinal direction of the fixing film is parallel to the rotation axis direction, but is not limited thereto. The first position of the restricting portion may be a position where the restricting surface has an inclination opposite to the second position of the present embodiment or a position inclined in the same direction as the second position.

105 fixing device 112 heater 114 fixing film 117 pressure roller 1201 L, 1201 R fixing flange 1201 La, 1201 Ra guide surface of fixing flange 1201 Lb, 1201 Rb fixing flange regulating surface 1201 Rab fixing flange regulating portion 1201 Rx fixing flange supporting portion 1201 Ry fixing flange gap 220R Fixing Flange 220Ra Fixing Flange Guide Surface 220Rb Fixing Flange Regulating Surface 220Rab Fixing Flange Regulating Section 220 Reu Elastic Member 220 Rek Elastic Member 220 Rss Fixing Flange Support N Fixing Nip P Recording Material

Claims (4)

Tubular film,
A nip forming member in contact with the inner surface of the film and elongated in the longitudinal direction of the film;
A roller forming a nip with the nip forming member via the film;
A surface which is provided at the longitudinal end of the film and which contacts the longitudinal end surface of the film when the film moves in the rotational axis direction of the roller and restricts the movement of the film with respect to the rotational direction of the film A first surface provided from the upstream side to the downstream side in the conveyance direction of the recording material in the nip portion, and a surface for guiding the inner peripheral surface of the film, and a circumference along the inner peripheral surface of the film A restricting portion having a second surface which is a surface;
And fixing the image on the recording material by heating while conveying the recording material on which the image is formed in the nip portion,
When the restricting portion is viewed in a direction perpendicular to both the rotational axis direction of the roller and the transport direction, at least the first surface is parallel to the rotational axis direction of the film. A first position parallel to the longitudinal end face of the film in one case, and a longitudinal direction of the film parallel to the rotation axis direction as the first surface is moved downstream with respect to the transport direction Configured to be tiltable between a second position away from the longitudinal end face of the film;
While the restricting portion tilts from the first position to the second position, a force is generated to tilt the restricting portion in a direction from the second position to the first position, and the force is the restriction A fixing device characterized in that the downstream side area of the transport direction of the unit is smaller than the upstream side area. The second plane is perpendicular to the first plane, and
When viewed in the perpendicular direction, when the restricting portion is at the first position, the generatrix of the second surface is parallel to the rotation axis direction, and the restricting portion is at the second position. 2. The fixing according to claim 1, wherein, at a given time, the generatrix of the second surface is inclined so as to be closer to the downstream side in the conveyance direction of the recording material as it approaches the longitudinal center of the film. apparatus. And a support portion on which the restricting portion is tiltably supported.
When viewed in the direction perpendicular to the vertical direction, the restriction portion is a fixed end fixed to the support portion at the upstream side in the conveyance direction, and a gap between the conveyance direction downstream side and the support portion The fixing device according to claim 1 or 2, wherein the fixing device is a free end provided with. And a support portion on which the restricting portion is tiltably supported.
When viewed in the vertical direction, the restriction portion is supported by the support portion on the upstream side in the transport direction via the first elastic member, and the downstream portion in the transport direction is the second Supported by the support via an elastic member of
The fixing device according to claim 1, wherein an elastic force of the second elastic member is smaller than an elastic force of the first elastic member.

Images