JP2013205506A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of creases on a recording material conveyed to a fixation nip part between a pressure member and a fixing member in a fixing device in which the fixing member is elastically deformed with pressure by the pressure member.SOLUTION: A fixing device comprises: a fixing roll which is rotationally provided, extends from one end to the other end along a rotation shaft, and is elastically deformed; a pressure member which presses the fixing roll and elastically deforms the pressed fixing roll to make the center part thereof in the rotation shaft direction concave, and forms a nip part with the fixing roll therebetween for fixing a toner image on a recording material by allowing the recording material to pass through the nip part; and a sheet guide member 71 which is provided upstream of the nip part in a recording material conveyance direction, has a concave shape in the center thereof in the rotation shaft direction in accordance with the shape of the fixing roll elastically deformed by the pressure member, and guides the recording material toward the nip part.

Description

  The present invention relates to a fixing device and an image forming apparatus.

As a conventional technique, for example, a fixing device that fixes an unfixed image in a fixing region formed between a heat fixing member and a pressure fixing member, and that elastically deforms the heat fixing member in the fixing region is known. (Patent Document 1).
Further, as a conventional technique, for example, a fixing device having a fixing unit, a pressure unit that forms a fixing nip portion between the fixing unit, and an inlet guide unit that guides the conveyance of the recording medium to the fixing nip unit. A fixing device is known that moves the inlet guide means in conjunction with the amount of biting of the pressure means relative to the fixing means (Patent Document 2).

JP 2010-2773 A JP 2011-48051 A

  In the fixing device in which the fixing member is elastically deformed by being pressed by the pressure member, the present invention improves the conveyance of the recording material conveyed to the fixing nip portion between the pressure member and the fixing member. With the goal.

The invention according to claim 1 is provided rotatably, extends from one end to the other end along the rotation axis, elastically deforms the fixing member, presses the fixing member, and rotates the fixing member in the direction of the rotation axis. The fixing member is elastically deformed so that the central portion is concave or convex, and a fixing nip portion for fixing the toner image on the recording material is formed by passing the recording material between the fixing member and the fixing member. A pressure member is provided upstream of the fixing nip portion in the recording material conveyance direction, and the central portion in the rotation axis direction is concave or convex in accordance with the shape of the fixing member elastically deformed by the pressure member. And a guide member that guides the recording material toward the fixing nip portion.
According to a second aspect of the present invention, there is provided setting means for setting the pressure member into a pressure state in which the fixing member is pressed and elastically deformed by pressing the fixing member, and a release state in which the pressure on the fixing member is released. Deformation means for deforming the guide member so that the central portion in the rotational axis direction is concave or convex according to the shape of the fixing member when the pressure member is set in the pressure state by the means; The fixing device according to claim 1, further comprising:
According to a third aspect of the present invention, when the pressing member is set to the released state by the setting unit, the deformation unit causes the guide member to be separated from the fixing member and / or the pressing member. The fixing device according to claim 2, wherein:
The invention according to claim 4 further includes a facing member provided to face the guide member, and the pressure member elastically fixes the fixing member so that the central portion in the rotation axis direction of the fixing member is concave. 3. The deforming device according to claim 2, wherein the deforming means deforms the guide member so that the central portion in the rotation axis direction is concave by bringing the facing member and the guide member into contact with each other. Item 4. The fixing device according to Item 3.
According to a fifth aspect of the present invention, the pressure member elastically deforms the fixing member so that a central portion in the rotation axis direction of the fixing member is concave, and the deformation means includes both ends in the rotation axis direction of the guide member. 4. The fixing device according to claim 2, wherein the guide member is deformed so that the central portion in the rotational axis direction becomes concave by pressing the portion toward the central portion in the rotational axis direction. 5. It is.

  According to a sixth aspect of the present invention, there is provided a toner image forming unit that forms a toner image, a transfer unit that transfers a toner image formed by the toner image forming unit onto a recording material, and a transfer unit that transfers the toner image onto the recording material. A fixing unit that fixes the toner image to the recording material, the fixing unit being rotatably provided, extending from one end to the other along the rotation axis, and elastically deforming a fixing member; By pressing the fixing member, the fixing member is elastically deformed so that the central portion in the rotation axis direction of the pressed fixing member is concave or convex, and a recording material is passed between the fixing member and the fixing member. A pressure member for forming a fixing nip portion for fixing a toner image on the recording material; and a pressure member provided upstream of the fixing nip portion in the recording material conveyance direction and before being elastically deformed by the pressure member. The rotation axis direction central portion in accordance with the shape of the fixing member is concave has a shape which is convex to an image forming apparatus comprising a guide member for guiding the recording material toward the fixing nip portion.

According to the first aspect of the present invention, in the fixing device in which the fixing member is elastically deformed by being pressed by the pressure member, the recording material conveyed to the fixing nip portion between the pressure member and the fixing member Transportability can be improved.
According to the second aspect of the present invention, it is possible to improve the transportability of the recording material transported to the fixing nip portion between the pressure member and the fixing member in the pressurized state.
According to invention of Claim 3, compared with the case where this structure is not employ | adopted, a contact with a guide member, a fixing member, and / or a pressurization member can be suppressed in a cancellation | release state.
According to the fourth aspect of the present invention, the guide member can be deformed with a simple configuration as compared with the case where the present configuration is not adopted.
According to the fifth aspect of the present invention, the guide member can be deformed with a simple configuration as compared with the case where the present configuration is not adopted.
According to the sixth aspect of the present invention, when the fixing member is elastically deformed by being pressed by the pressure member, the recording material is conveyed to the fixing nip portion between the pressure member and the fixing member. Can be improved.

FIG. 2 is a diagram illustrating a configuration example of an image forming apparatus to which the fixing device according to the first embodiment is applied. 1 is a perspective view of a fixing device according to a first embodiment. It is III-III sectional drawing in FIG. 2 is a perspective view of a fixing device in a pressurized state according to Embodiment 1. FIG. It is IV-IV sectional drawing in FIG. FIG. 5 is a diagram of a fixing roll and a pressure member as viewed from the upstream side in the paper conveyance direction in a pressure fixing device. FIG. 6 is a diagram for explaining a shape of a paper guide member according to the first embodiment. 6 is a perspective view of a fixing device in a released state according to Embodiment 2. FIG. 6 is a perspective view of a fixing device in a pressurized state according to Embodiment 2. FIG. It is sectional drawing of the fixing device of the cancellation | release state shown in FIG. FIG. 10 is a cross-sectional view of the fixing device shown in FIG. 9. FIG. 6 is a diagram of a paper guide member and a pressing member according to Embodiment 2 as viewed from the downstream side in the paper transport direction. 6 is a perspective view of a fixing device in a released state according to Embodiment 3. FIG. 6 is a perspective view of a fixing device in a pressurized state according to Embodiment 3. FIG. FIG. 3 is a diagram of the fixing device according to the present embodiment as viewed from the upstream side in the paper conveyance direction. FIG. 6 is a diagram of an end portion in the width direction of the fixing device in a pressurized state as viewed from the upstream side in the paper conveyance direction.

[Embodiment 1]
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a configuration example of an image forming apparatus 1 to which the fixing device 20 of the present embodiment is applied. An image forming apparatus 1 shown in FIG. 1 includes an image forming unit 100 that forms an image on a sheet P as an example of a recording material based on image data, a control unit 300 that controls the operation of the entire image forming apparatus 1, and an image forming unit. A paper supply unit 30 that supplies the paper P to the unit 100, a paper reversing mechanism 50 that reverses the front and back of the paper P on which the image is formed by the image forming unit 100, and supplies the paper P to the image forming unit 100 again. A paper stacking unit YS for stacking paper P on which an image is formed is provided. Further, the image forming apparatus 1 includes a toner cartridge 60 that supplies toner to the image forming unit 100. Further, the image forming apparatus 1 performs communication with a personal computer (PC) or the like, for example, a receiving unit 200 that receives image data, and an image that performs predetermined image processing on the image data received by the receiving unit 200. The processing unit 400 includes a user interface (UI) 500 that receives instructions from the user and displays messages and the like to the user.

  Further, the image forming apparatus 1 according to the present embodiment is provided with a paper transport path YR through which paper is transported from the paper supply unit 30 to the paper stacking unit YS via the transfer unit Tp and the fixing device 20. . Further, the sheet P is connected to the sheet conveyance path YR on the downstream side of the fixing device 20 and joined to the sheet conveyance path YR on the upstream side of the transfer unit Tp. A reversing transport path SR for transporting to the forming unit 100 is provided.

  The image forming unit 100 according to the present embodiment includes a photosensitive layer on the surface, forms a latent electrostatic image and holds a toner image, and a charging device 12 that charges the photosensitive drum at a predetermined potential. , An exposure device 13 for exposing the photosensitive drum 11 charged by the charging device 12 based on image data, a developing device 14 for developing the electrostatic latent image formed on the photosensitive drum 11, and the photosensitive drum 11 after transfer. A cleaning device 16 is provided for cleaning the surface.

  Further, the image forming unit 100 forms a transfer unit Tp between the image forming unit 100 and the transfer unit as an example of a transfer unit that transfers the toner image formed on the photoconductive drum 11 onto the paper P. 15 and a fixing device 20 as an example of fixing means for fixing the toner image transferred onto the paper P by the transfer device 15 onto the paper P. The configuration of the fixing device 20 will be described in detail later.

Further, the image forming unit 100 is provided with a registration roll (registration roll) 47, a discharge roll 49 and a transport roll 51.
The registration roll 47 temporarily stops the conveyance of the sheet P in a state where the rotation is stopped, and rotates the sheet P at a predetermined timing, thereby supplying the sheet P while performing registration adjustment on the transfer portion Tp. .
The discharge roll 49 discharges the paper P, which has been subjected to the fixing process by the fixing device 20, toward the paper stacking unit YS on the downstream side of the fixing device 20.
The transport roll 51 transports the paper P whose front and back are reversed by the paper reversing mechanism 50 toward the registration roll 47 again.

  The paper supply unit 30 of this embodiment includes a paper storage unit 31, a pulling roll 33, and a winding mechanism 35. The paper storage unit 31 has, for example, a rectangular parallelepiped shape having an opening in the upper portion, and stores a plurality of papers P therein. The pull-in roll 33 sends out the upper sheet P of the plurality of sheets P stored in the sheet storage unit 31 toward the winding mechanism 35. The webbing mechanism 35 webs the paper P sent out by the pull-in roll 33 one by one and sends it out to the registration roll 47.

Next, an image forming process performed in the image forming apparatus 1 according to the present embodiment will be described.
First, image data formed by a PC or the like is received by the receiving unit 200, and the image data is output from the receiving unit 200 to the image processing unit 400. The image data output to the image processing unit 400 is subjected to image processing by the image processing unit 400 and output to the exposure apparatus 13. The exposure device 13 that has acquired the image data selectively exposes the photosensitive drum 11 charged by the charging device 12 based on the acquired image data to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 11 is developed by the developing device 14 as, for example, a black (K) toner image.

  On the other hand, in the paper supply unit 30, the drawing roll 33 rotates in synchronization with the image formation timing, and the paper P is supplied from the paper storage unit 31. Then, the sheets P that are rolled up one by one by the winding mechanism 35 are conveyed to the registration roll 47 and are temporarily stopped. Thereafter, the registration roll 47 rotates in accordance with the rotation timing of the photosensitive drum 11, and the paper P is supplied to the transfer portion Tp. Then, the toner image formed on the photosensitive drum 11 is transferred onto the paper P in the transfer portion Tp.

Thereafter, the sheet P on which the toner image is transferred undergoes a fixing process in the fixing device 20 and is discharged to the sheet stacking unit YS by the discharge roll 49. When an image is formed not only on the first side of the paper P but also on the second side (images are formed on both sides of the paper P), the paper P that has passed through the fixing device 20 is fed by the paper reversing mechanism 50. After the front and back sides are reversed, the sheet is supplied again to the transfer portion Tp. Then, the toner image formed on the photosensitive drum 11 is transferred to the second surface of the paper P at the transfer portion Tp. Thereafter, the sheet P on which the toner image is transferred to the second surface is subjected to a fixing process by the fixing device 20 and is discharged to the sheet stacking unit YS by the discharge roll 49.
In this way, the image forming process in the image forming apparatus 1 is repeatedly executed for the number of printed sheets.

Next, the fixing device 20 of the present embodiment will be described. FIG. 2 is a perspective view of the fixing device 20 of the present embodiment. 3 is a cross-sectional view taken along line III-III in FIG.
As shown in FIGS. 2 and 3, the fixing device 20 of the present embodiment includes a fixing roll 21 as an example of a fixing member, and a pressure member 22 provided to face the fixing roll 21. As shown in FIGS. 2 and 3, the fixing device 20 according to the present embodiment switches the contact state between the fixing roll 21 and the pressing member 22, the frame 81 that supports the fixing roll 21 and the pressing member 22, and the pressing member 22. A switching lever 82 is provided as an example of setting means and deformation means. Further, as shown in FIGS. 2 and 3, the fixing device 20 according to the present embodiment is in contact with a sheet guide member 71 as an example of a guide member that guides the sheet P to be conveyed, and the sheet guide member 71. An abutting member 91 as an example of an opposing member that changes the shape of the paper guiding member 71 by pushing the guiding member 71 and a positioning member 92 that defines the position of the abutting member 91 are provided.

In the fixing device 20 of the present embodiment, the pressure member 22 presses the fixing roll 21 by the switching lever 82, and a nip portion N (see FIG. 5) is formed between the fixing roll 21 and the pressure member 22. The pressing state to the fixing roll 21 by the pressing member 22 is released, and the releasing state in which the fixing roll 21 and the pressing member 22 are separated from each other can be switched. Accordingly, for example, when a paper jam occurs in the fixing device 20, the fixing device 20 is switched to the release state, so that the jammed paper P can be easily removed from the fixing device 20 as compared with the case without this configuration. Can be removed.
FIG. 4 is a perspective view of the fixing device 20 in a pressurized state according to the present embodiment. 5 is a cross-sectional view taken along line VV in FIG. 2 and 3 described above show the fixing device 20 in the released state.

  The fixing roll 21 has a cylindrical shape as a prototype. For example, the outer peripheral surface of the prototype (cylindrical shape) has a diameter of 30 mm and a thickness of 0.1 mm. The fixing roll 21 is made of, for example, nickel steel, is elastically deformable, and is configured to hold a cylindrical shape by its own rigidity.

The material constituting the fixing roll 21 and the dimensions of the fixing roll 21 are not limited to those described above. As a material constituting the fixing roll 21, for example, stainless steel, nickel-cobalt alloy, copper, gold, nickel-iron alloy, and the like can be used in addition to nickel steel. Further, the thickness of the fixing roll 21 may be any thickness as long as the fixing roll 21 can be elastically deformed and can retain the cylindrical shape by rigidity, and is preferably 0.07 mm to 0.12 mm, for example.
Furthermore, in order to improve the peeling performance of the paper P from the fixing roll 21, a surface layer made of a fluororesin having good releasability may be further provided on the outer peripheral surface of the fixing roll 21.

A heater 21 a is provided inside the fixing roll 21. For example, a 570 W halogen lamp can be used as the heater 21a.
As shown in FIGS. 3 and 5, in the present embodiment, the heater 21a is disposed in a state of being separated from the fixing roll 21, and the inner peripheral surface of the fixing roll 21 and the heater 21a are not in contact with each other. . In the present embodiment, the support member for maintaining the shape of the fixing roll 21 as in the related art is not provided on the inner peripheral surface of the fixing roll 21. Therefore, the fixing roll 21 and the heater 21a are arranged so as to face each other directly, and the fixing roll 21 can be directly heated by the heater 21a.

  The pressure member 22 faces the fixing roll 21 and is provided on an endless pressure belt 22a that is rotatably provided and on the inner peripheral side of the pressure belt 22a. And a pressing pad 22b for pressing the fixing roll 21.

The pressure belt 22a of the present embodiment is formed with a diameter of 30 mm and a width of 370 mm, for example. In the following description, the width direction of the pressure belt 22a (that is, the direction perpendicular to the paper surface in FIG. 3) may be simply referred to as “width direction”.
The pressure belt 22a is, in order from the inner peripheral surface side, a base layer made of a sheet-like member having high heat resistance, an elastic layer laminated on the base layer, and an outer layer of the pressure belt 22a. A surface release layer exposed on the surface is laminated.

As the base layer, a flexible material having excellent mechanical strength and heat resistance is used. Examples of the material constituting the base layer include fluorine resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK (polyetheretherketone) resin, PES (polyethersulfone) resin, PPS (polyphenylene sulfide) resin, and PFA resin. PTFE (polytetrafluoroethylene) resin, FEP (tetrafluoroethylene hexafluoropropylene copolymer) resin, and the like. The thickness of the base layer is preferably, for example, 10 to 150 μm, and more preferably 30 to 100 μm.
As the elastic layer, silicone rubber, fluorine rubber, fluorosilicone rubber or the like having excellent heat resistance and thermal conductivity is used. 10-500 micrometers is preferable and, as for thickness, 50-300 micrometers is more preferable.
As the surface release layer, for example, PFA resin, PTFE resin, fluororesin, silicone resin, fluorosilicone rubber, silicone rubber or the like is used.

As shown in FIGS. 3 and 5, the pressing pad 22 b is provided along the inner peripheral surface of the pressure belt 22 a. Then, as shown in FIG. 5, the pressing pad 22 b presses the fixing roll 21 through the pressing belt 22 a in a pressurized state, and forms a nip portion N between the pressing pad 22 b and the fixing roll 21.
Examples of the material constituting the pressing pad 22b include elastic bodies such as silicone rubber and fluororubber, and heat resistant resins such as LCP (Liquid Crystal Polymer) and PPS (polyphenylene sulfide).

  In addition, in order to improve the slidability between the pressure belt 22a and the pressure pad 22b in the nip portion N between the pressure belt 22a and the pressure pad 22b, a polyimide having excellent slidability and high wear resistance. A sliding sheet (not shown) made of a glass fiber sheet impregnated with a film or a fluororesin is provided. Further, a lubricant such as amino-modified silicone oil or dimethyl silicone oil is applied to the inner peripheral surface of the pressure belt 22a. As a result, the frictional resistance between the pressure belt 22a and the pressing pad 22b is reduced, and the pressure belt 22a rotates smoothly.

  In the present embodiment, the fixing roll 21 is rotationally driven in one direction (counterclockwise in FIG. 3) at a predetermined speed by a driving force of a driving motor (not shown). The pressure belt 22 a provided in contact with the fixing roll 21 is driven to rotate in one direction (clockwise in FIG. 3) following the fixing roll 21 as the fixing roll 21 rotates. That is, the pressure belt 22 a rotates in conjunction with the fixing roll 21 by receiving a rotational driving force from the fixing roll 21.

The sheet guide member 71 is made of, for example, a resin or metal having a predetermined rigidity, and has a plate shape. As shown in FIGS. 3 and 5, the sheet guide member 71 has one surface facing the fixing roll 21 side and the other surface facing the pressure member 22 side upstream of the nip portion N in the sheet conveyance direction. Thus, it is provided along the paper transport direction. The end of the sheet guide member 71 on the downstream side in the sheet conveyance direction is opposed to the entrance portion where the sheet P is inserted into the nip portion N.
In the following description, one surface of the paper guide member 71 facing the fixing roll 21 side is called a first surface, and the other surface facing the pressure member 22 side is called a second surface. is there.
The paper guide member 71 of the present embodiment is configured so that the shape is different between the pressurized state and the released state. The shape of the sheet guide member 71 in the pressurized state and the released state will be described in detail later.

  The frames 81 are provided at both ends in the width direction of the fixing device 20 so as to face each other with the fixing roll 21 and the pressure member 22 interposed therebetween. The frame 81 rotatably supports the fixing roll 21 and the pressure member 22 at both ends in the width direction of the fixing roll 21 and the pressure member 22.

The switching lever 82 is provided on the frame 81 so that it can be pushed down or pushed up at both ends in the width direction of the fixing device 20. The switching lever 82 is pushed down or pushed up in a predetermined direction to move the position of the pressure member 22 relative to the fixing roll 21. Thereby, the switching lever 82 switches the contact state between the fixing roll 21 and the pressure member 22 between a pressure state and a release state.
In addition, although mentioned later for details, in this Embodiment, it is comprised so that the abutting member 91 may also be moved, when the switching lever 82 is pushed down or pushed up.

The abutting member 91 includes a curved portion 91a that is curved, and a flat surface portion 91b that extends from the curved portion 91a, and is configured by a plate-like member that is formed to have a U-shaped cross section. 4 and 5, the flat surface portion 91b presses the central portion in the width direction on the second surface of the paper guide member 71 in the pressurized state, thereby deforming the paper guide member 71. .
The abutting member 91 according to the present embodiment is separated from the state in which the paper guide member 71 is pressed and the paper guide member 71 in conjunction with the switching between the pressurized state and the released state by the switching lever 82. It is comprised so that it can switch to a state.

The positioning member 92 has a columnar shape, extends from one end in the width direction to the other end in the width direction in the fixing device 20, and passes through the inner peripheral side of the curved portion 91 a of the abutting member 91. Is provided. As shown in FIG. 5, the abutting member 91 is positioned when the inner peripheral surface of the curved portion 91 a of the abutting member 91 contacts the positioning member 92 in the pressurized state.
Note that the positioning member 92 of the present embodiment is configured such that the position with respect to the fixing roll 21 does not move between the pressurized state and the released state.

Next, the shapes of the fixing roll 21 and the pressure member 22 in the release state and the pressure state will be described.
Here, as described above, the fixing roll 21 of the present embodiment is configured to be elastic. As a result, the shape of the fixing roll 21 is different between the pressed state in which the fixing roll 21 is pressed by the pressing member 22 and the released state in which the fixing roll 21 and the pressing member 22 are separated.
FIG. 6 is a view of the fixing roll 21 and the pressure member 22 as viewed from the upstream side in the conveyance direction of the paper P in the fixing device 20 of the present embodiment. FIG. 6A shows the fixing roll 21 and the pressure member 22 in the released state, and FIG. 6B shows the fixing roll 21 and the pressure member 22 in the pressurized state.

  As shown in FIG. 6A, in the released state, the nip portion N is not formed between the fixing roll 21 and the pressure member 22, and the fixing roll 21 and the pressure member 22 are separated from each other. ing. The fixing roll 21 and the pressure member 22 extend from one end in the width direction toward the other end in the width direction. Thereby, a space extending from one end in the width direction to the other end in the width direction is formed between the fixing roll 21 and the pressure member 22.

On the other hand, in the pressurized state, the pressure member 22 presses the fixing roll 21, and a nip portion N is formed between the fixing roll 21 and the pressure member 22.
Further, as shown in FIG. 6B, in the pressurized state, the pressure member 22 is elastically deformed, and when viewed from the upstream side in the conveyance direction of the paper P, the central portion in the width direction faces the fixing roll 21 side. And bends to become convex.
Thereby, in the pressurized state, the fixing roll 21 pressed by the pressure member 22 is elastically deformed following the pressure member 22. That is, in the pressurized state, as shown in FIG. 6B, the fixing roll 21 is recessed toward the side away from the pressure member 22 in the center in the width direction and curved from one end in the width direction to the other end in the width direction. It has a shape.

In the pressure state, the fixing roll 21 and the pressure member 22 have the above-described shape, so that the nip portion N formed between the fixing roll 21 and the pressure member 22 is from the upstream side in the sheet conveyance direction. As seen, the central portion in the width direction is recessed toward the fixing roll 21 as compared with the end portion in the width direction, and has a shape curved from one end in the width direction to the end portion in the width direction.
In the present embodiment, the deflection amount d of the nip portion N shown in FIG. 6B is about 0.8 mm to 1 mm, for example.

Next, a fixing operation performed in the fixing device 20 will be described.
When forming an image in the image forming apparatus 1 (see FIG. 1), the fixing device 20 is set in a pressurized state by pushing down the switching lever 82 in the fixing device 20 in the direction of arrow C (see FIG. 3). Subsequently, when an operation for forming a toner image is started in the image forming unit 100 (see FIG. 1), a heater 21a provided on the fixing roll 21 and a drive motor (not shown) for driving the fixing roll 21 are used. Power is supplied. As a result, the fixing roll 21 generates heat and rotates, and the pressure member 22 rotates as the fixing roll 21 rotates. The fixing roll 21 is heated to a predetermined temperature, and the pressure member 22 is also heated via the fixing roll 21. The fixing temperature at which the fixing roll 21 is heated is set to 180 ° C., for example.

Next, the paper P on which the toner image has been transferred by the transfer device 15 at the transfer portion Tp is guided by the paper guide member 70 to the nip portion N formed between the fixing roll 21 and the pressure member 22. Be transported. The toner image is fixed on the sheet P conveyed to the nip portion N by the heat supplied from the fixing roll 21 and the pressure acting between the fixing roll 21 and the pressure member 22 in the nip portion N.
Subsequently, the paper P on which the toner image is fixed in the nip portion N is peeled off from the fixing roll 21 and the pressure member 22 and discharged to the paper stacking portion YS.

In the present embodiment, as described above, the nip portion N formed between the fixing roll 21 and the pressure member 22 is fixed by the fixing roll 21 being pressed and elastically deformed by the pressure member 22. Compared with the case where the roll 21 is not elastically deformed, it is wider.
As a result, the contact area between the sheet P and the fixing roll 21 is widened compared to the case where this configuration is not adopted, heat transfer from the fixing roll 21 to the sheet P is improved, and the toner image on the sheet P is improved. It is possible to improve the fixing performance.
In addition, compared with the case where this configuration is not employed, both the contact area between the paper P and the fixing roll 21 and the contact area between the paper P and the pressure member 22 are increased in the nip portion N. It becomes possible to improve the conveyance performance of the recording material P by the pressure member 22.

  When a paper jam or the like occurs in the nip portion N, the fixing device 20 is set to the released state by pushing up the switching lever 82 in the direction of arrow D (see FIG. 5). As a result, as shown in FIG. 6A, the fixing roll 21 and the pressure member 22 are separated from each other, and the paper jammed between the fixing roll 21 and the pressure member 22 can be easily removed. Can be done.

Here, in the present embodiment, the sheet P is guided toward the nip portion N by the sheet guide member 71 in the fixing operation. For example, when the paper guide member 71 has a horizontal shape along the width direction as in the prior art, the paper P guided by the paper guide member 71 follows the paper guide member 71 along the width direction. Therefore, the sheet is conveyed toward the inlet portion of the nip portion N while maintaining a horizontal shape.
As described above, in the present embodiment, in the pressurized state, the shape of the inlet portion of the nip portion N is a shape in which the central portion in the width direction is recessed toward the fixing roll 21 and curved from one end in the width direction to the other end in the width direction. have. Thus, when the paper P is transported toward the nip portion N while maintaining a horizontal shape along the width direction, the shape of the front side of the paper P in the transport direction and the shape of the inlet portion of the nip portion N are Due to the difference, the paper P may not follow the nip portion N and may abut against the fixing roll 21 or the pressure member 22. When the paper P hits the fixing roll 21 or the pressure member 22, there is a possibility that the paper P is wrinkled or dirty.

  Therefore, in the present embodiment, in order to prevent the paper P guided toward the nip N by the paper guide member 71 from being wrinkled or contaminated, the nip N The sheet guide member 71 is deformed according to the shape of the sheet.

  Subsequently, the shape of the sheet guide member 71 of the present embodiment in each of the released state and the pressurized state will be described in detail. FIG. 7 is a view for explaining the shape of the sheet guide member 71 of the present embodiment. FIG. 7A is a sectional view taken along the line VIIA-VIIA in FIG. 3 and shows the sheet guide member 71, the abutting member 91, and the positioning member 92 in the released state. FIG. 7B is a sectional view taken along the line VIIB-VIIB in FIG. 5 and shows the paper guide member 71, the abutting member 91, and the positioning member 92 in a pressurized state.

First, the shape of the sheet guide member 71 in the released state will be described.
As shown in FIGS. 3 and 7A, in the released state, the flat surface portion 91 b of the abutting member 91 is in a state of being separated from the second surface of the paper guide member 71. As a result, as shown in FIG. 7A, the paper guide member 71 has a substantially horizontal shape from one end in the width direction to the other end in the width direction due to its own rigidity. That is, in the released state, the paper guide member 71 has a shape along the fixing roll 21 and the pressure member 22 that extend along the width direction.
Therefore, for example, when a paper jam occurs between the fixing roll 21 and the pressure member 22 and the fixing device 20 is switched to the release state, the paper P removed from between the fixing roll 21 and the pressure member 22 is used. Is prevented from colliding with the paper guide member 71, and paper jam can be easily eliminated as compared with the case where this configuration is not adopted.

In the released state, the pressing against the central portion in the width direction of the paper guide member 71 by the abutting member 91 is released. As a result, the distance between the central portion in the width direction of the paper guide member 71 and the fixing roll 21 and the pressure member 22 is increased as compared with the state where the paper guide member 71 is pressed by the abutting member 91. Yes.
Therefore, compared with the case where this configuration is not adopted, the contact between the sheet guide member 71, the fixing roll 21, and the pressure member 22 in the released state is suppressed, and the fixing roll 21 and the pressure member 22 are damaged. It can suppress sticking.

Next, the shape of the paper guide member 71 in the pressurized state will be described.
As shown in FIG. 5 and FIG. 7B, in the pressurized state, the flat surface portion 91 b of the abutting member 91 is in contact with the central portion in the width direction on the second surface of the paper guide member 71. Yes. The sheet guide member 71 is elastically deformed by pressing the center portion in the width direction by the abutting member 91, and the first surface side of the sheet guide member 71 is compared with the end portion in the width direction. The shape is curved so as to be convex (the second surface side is concave). That is, in the pressure state, the paper guide member 71 has a shape that follows the shape of the nip portion N formed between the fixing roll 21 and the pressure member 22.

  With such a configuration, in the fixing operation, the sheet P is conveyed toward the nip portion N while being deformed following the shape of the sheet guide member 71. That is, the paper P is guided to the nip portion N in a state where the shape of the front side in the transport direction of the paper P is equal to the shape of the inlet portion of the nip portion N. Thereby, compared with the case where this configuration is not adopted, the paper P is easily inserted into the nip portion N, and the paper P can be prevented from colliding with the fixing roll 21 and the pressure member 22. Then, it is possible to suppress the generation of wrinkles on the paper P and the adhesion of dirt to the paper P due to the paper P colliding with the fixing roll 21 and the pressure member 22.

In the present embodiment, the abutting member 91 is in a state where the inner peripheral surface of the bending portion 91a is in contact with the positioning member 92, and the position with respect to the paper guide member 71 is defined.
Here, as described above, the positioning member 92 is provided so that the position with respect to the fixing roll 21 does not change between the released state and the pressed state. Therefore, when the abutting member 91 is brought into contact with the paper guide member 71 in the pressurized state, the position of the abutting member 91 is defined by the positioning member 92, so that the position of the abutting member 91 is set to the fixing roll 21. It is possible to suppress being too close. As a result, compared to the case where this configuration is not adopted, the sheet guide member 71 pressed by the abutting member 91 collides with the fixing roll 21 in a pressurized state, thereby suppressing the fixing roll 21 from being damaged. It becomes possible.

In this embodiment, as shown in FIG. 5, the abutting member 91 is in contact with the paper guide member 71 on the downstream side of the paper guide member 71 in the paper transport direction and presses the paper guide member 71. Thereby, the paper guide member 71 of the present embodiment is deformed so that the curvature of the paper guide member 71 gradually increases from the upstream side in the paper transport direction to the downstream side in the paper transport direction.
In the present embodiment, the sheet guide member 71 is deformed into such a shape, so that the sheet P guided by the sheet guide member 71 gradually moves from the upstream side in the sheet transport direction to the downstream side in the sheet transport direction. Then, it will be deformed into a curved shape. Thereby, compared with the case where this structure is not employ | adopted, it can suppress that the paper P is bent sharply by the paper guide member 71, and it becomes possible to suppress that a wrinkle arises in the paper P.

Next, the switching operation between the release state and the pressure state in the fixing device 20 will be described.
When the fixing device 20 is switched from the release state to the pressure state when performing an image forming operation or the like, first, the switching lever 82 is pushed down in the direction of arrow C (see FIG. 3). Thereby, the pressing pad 22b in the pressing member 22 is urged toward the fixing roll 21 by an urging member (not shown) such as a coil spring. Then, as shown in FIG. 5, the pressure belt 22 a is pressed against the fixing roll 21 by the pressing pad 22 b, and the nip portion N having the curved shape as described above is interposed between the fixing roll 21 and the pressure member 22. Is formed.

  Further, in the present embodiment, as described above, the abutting member 91 is configured to move as the switching lever 82 is pushed down. That is, by pushing down the switching lever 82, the abutting member 91 moves toward the paper guide member 71. The abutting member 91 has the inner peripheral surface of the curved portion 91a in contact with the positioning member 92 in a state where the flat surface portion 91b is in contact with the second surface of the paper guide member 71 and presses the paper guide member 71. Positioned. As a result, as shown in FIG. 7B, the paper guide member 71 has a curved shape.

Further, when the fixing device 20 is switched from the pressure state to the release state when a paper jam or the like occurs, the switch lever 82 is first pushed up in the direction of arrow D (see FIG. 5). As a result, the pressure member 22 moves away from the fixing roll 21, and a space is formed between the fixing roll 21 and the pressure member 22 as shown in FIG. 3.
Further, as the switching lever 82 is pushed up, the abutting member 91 moves away from the paper guide member 71. Thereby, the pressing from the abutting member 91 to the paper guide member 71 is released, and the paper guide member 71 becomes a horizontal shape along the width direction as shown in FIG.

As described above, in the present embodiment, the sheet guide member 71 is formed in the shape of the nip portion N in the pressurized state in which the nip portion N has a curved shape as the fixing roll 21 is pressed by the pressure member 22. It was elastically deformed according to. As a result, the paper P guided by the paper guide member 71 is guided to the nip N while being deformed according to the shape of the nip N, and the paper P is guided to the fixing roll 21 and the pressure member 22. It is possible to suppress the occurrence of wrinkles on the paper P due to the collision and the contamination of the paper P.
Further, when the fixing device 20 is switched to a release state in which the fixing roll 21 and the pressure member 22 are separated from each other, the elastic deformation of the paper guide member 71 is released, so that the paper guide member 71, the fixing roll 21, and the pressurization member 21 are added. The distance from the pressure member 22 is set to be farther from that in the pressurized state. Thereby, it is possible to suppress the collision between the sheet guide member 71 and the fixing roll 21 or the pressure member 22 in the released state, and it is possible to suppress the flaw from being generated on the fixing roll 21 or the pressure member 22.

[Embodiment 2]
Next, a second embodiment of the present invention will be described. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol as Embodiment 1 is used, and detailed description is abbreviate | omitted here.
FIG. 8 is a perspective view of the fixing device 20 in the released state according to the second embodiment. FIG. 9 is a perspective view of the fixing device 20 in a pressurized state according to the second embodiment. 10 is a sectional view of the fixing device 20 in the released state shown in FIG. 8, and FIG. 11 is a sectional view of the fixing device 20 shown in FIG. 10A is a cross-sectional view taken along the line XA-XA in FIG. 8 and shows a cross-sectional view of the center portion in the width direction of the fixing device 20 in the released state. FIG. 10B is a cross-sectional view taken along the line XB-XB in FIG. 8 and shows a cross-sectional view of the end portion in the width direction of the fixing device 20 in the released state. FIG. 11A is a cross-sectional view taken along the line XIA-XIA of FIG. 9 and shows a cross-sectional view of the center portion in the width direction of the fixing device 20 in a pressurized state. FIG. 11B is a cross-sectional view taken along the line XIB-XIB in FIG. 9 and shows a cross-sectional view of the end portion in the width direction of the fixing device 20 in a pressurized state. 10 and 11, the pressure belt 22a and the pressure pad 22b are not shown, and are shown as the pressure member 22 together.

  As shown in FIGS. 8 to 11, the fixing device 20 according to the present embodiment includes a fixing roll 21 as an example of a fixing member, a pressure member 22, a sheet guide member 71 as an example of a guide member, and a frame. 81 and a switching lever 82 as an example of setting means and deformation means. Furthermore, the fixing device 20 according to the present embodiment includes a pressing member 93 as an example of an opposing member that elastically deforms the paper guide member 71 when the paper guide member 71 is pressed.

  The sheet guide member 71 of the present embodiment is a plate that extends from one end in the width direction to the other end in the width direction, with one surface facing the fixing roll 21 side and the other surface facing the pressure member 22 side. A guide portion 71a that guides the paper P to the nip portion N, and a bent portion 71b that is bent from the upstream end of the guide portion 71a toward the fixing roll 21. . An end portion of the guide portion 71a of the paper guide member 71 on the downstream side in the paper transport direction faces the nip portion N. As in the first embodiment, one surface of the guide portion 71a of the paper guide member 71 facing the fixing roll 21 is called a first surface, and the other surface facing the pressure member 22 is a second surface. Sometimes called the surface.

  The sheet guide member 71 of the present embodiment is provided so as to be movable, and is configured such that the position with respect to the pressing member 93 changes between the released state and the pressed state. Further, the sheet guide member 71 of the present embodiment is configured so that the shape is different between the released state and the pressurized state. The configuration of the sheet guide member 71 in each of the released state and the pressurized state will be described in detail later.

The switching lever 82 of the present embodiment is provided on the frame 81 so that it can be pushed down or pushed up at both ends in the width direction of the fixing device 20. As shown in FIG. 8, the switching lever 82 according to the present embodiment moves the paper guide member 71 to the side facing the paper guide member 71 by contacting the paper guide member 71 and pushing the paper guide member 71. The contact part 82a to be made is provided.
Then, the switching lever 82 according to the present embodiment moves down the predetermined direction in the same manner as in the first embodiment, or moves the position of the pressure member 22 relative to the fixing roll 21 by being pushed up. As a result, the switching lever 82 switches the contact state between the fixing roll 21 and the pressure member 22 between a pressure state and a release state.
Further, the switching lever 82 of the present embodiment moves the paper guide member 71 by pressing the paper guide member 71 when the contact portion 82a comes into contact with the bent portion 71b of the paper guide member 71 in the pressurized state. The guide member 71 is pressed against the pressing member 93.

In the fixing device 20, the pressing member 93 extends from one end in the width direction to the other end in the width direction, and is provided to face the second surface of the sheet guide member 71. In the pressing member 93 according to the present embodiment, the central portion in the width direction of the surface facing the second surface of the paper guide member 71 is compared with the second surface of the paper guide member 71 in comparison with the end portion in the width direction. It has an outer shape that becomes convex.
The pressing member 93 according to the present embodiment elastically deforms the guide portion 71a of the paper guide member 71 when the paper guide member 71 moved by the contact portion 82a of the switching lever 82 abuts in the pressurized state. ing.

  Subsequently, the configuration of the sheet guide member 71 in each of the released state and the pressurized state will be described. FIG. 12 is a view of the sheet guide member 71 and the pressing member 93 according to the present embodiment as viewed from the downstream side in the sheet conveyance direction (that is, the nip portion N side). 12A shows the paper guide member 71 and the pressing member 93 in the released state, and FIG. 12B shows the paper guide member 71 and the pressing member 93 in the pressurized state.

First, the configuration of the sheet guide member 71 in the released state will be described.
As shown in FIGS. 8 and 10, in the released state, the switching lever 82 is pushed up, and the contact portion 82 a of the switching lever 82 is separated from the bent portion 71 b of the paper guide member 71. . Thus, in the released state, the sheet guide member 71 does not receive the pressing force from the switching lever 82, and the guide portion 71a of the sheet guide member 71 has one end in the width direction due to its own rigidity, as shown in FIG. The shape is substantially horizontal along the width direction from the other end in the width direction.
In the present embodiment, in the released state, the central portion in the width direction of the second surface of the guide portion 71a of the paper guide member 71 is pressed as shown in FIGS. 10 (a) and 12 (a). The member 93 is in contact with the central portion in the width direction. On the other hand, in the released state, the end portion in the width direction of the second surface of the guide portion 71a of the sheet guide member 71 is the end in the width direction of the pressing member 93 as shown in FIGS. 10 (a) and 12 (a). It is in a state separated from the part.

Next, the configuration of the paper guide member 71 in the pressurized state will be described.
In the present embodiment, when the switching lever 82 is pushed down in order to switch the fixing device 20 from the released state to the pressurized state, as shown in FIGS. 9 and 11, the contact portion 82a of the switching lever 82 is moved to the sheet guide. It will be in the state which contacted the both ends of the width direction in the bending part 71b of the member 71, respectively.
Then, the sheet guide member 71 moves by being pressed by the switching lever 82 via the bent portion 71 b, and the guide portion 71 a is pressed against the pressing member 93. The guide portion 71a of the paper guide member 71 pressed against the pressing member 93 is elastically deformed following the shape of the pressing member 93 as shown in FIG.

  As described above, the pressing member 93 has an outer shape in which the central portion in the width direction of the surface facing the paper guide member 71 is convex toward the paper guide member 71 compared to the end in the width direction. doing. Therefore, as shown in FIG. 12B, the guide portion 71a of the paper guide member 71 in the pressurized state has a convex central portion in the width direction of the first surface (that is, the central portion in the width direction on the second surface side). Is a concave shape). That is, in the pressure state, the guide portion 71 a of the paper guide member 71 has a curved shape following the shape of the nip portion N formed between the fixing roll 21 and the pressure member 22.

  With the sheet guide member 71 having such a configuration in the pressurized state, the sheet P is directed toward the nip N while being deformed following the shape of the guide portion 71a of the sheet guide member 71 in the fixing operation. Be transported. That is, the paper P is guided to the nip portion N in a state where the shape of the front side in the transport direction of the paper P is equal to the shape of the inlet portion of the nip portion N. Thereby, compared with the case where this configuration is not adopted, the paper P is easily inserted into the nip portion N, and the paper P can be prevented from colliding with the fixing roll 21 and the pressure member 22. Then, it is possible to suppress the generation of wrinkles on the paper P and the adhesion of dirt to the paper P due to the paper P colliding with the fixing roll 21 and the pressure member 22.

Further, in the present embodiment, as shown in FIG. 11, the downstream side in the paper transport direction of the guide portion 71 a of the paper guide member 71 is in contact with the pressing member 93. Thereby, the guide portion 71a of the paper guide member 71 in the present embodiment is elastically deformed along the pressing member 93 on the downstream side in the paper transport direction. The guide portion 71a is deformed into a shape in which the curve gradually increases from the upstream side in the paper transport direction to the downstream side in the paper guide direction.
Therefore, in the present embodiment, the guide portion 71a of the paper guide member 71 is deformed in such a shape, so that the paper P guided by the guide portion 71a of the paper guide member 71 is upstream in the paper transport direction. And gradually deformed into a curved shape from the downstream side in the sheet conveyance direction. Thereby, compared with the case where this structure is not employ | adopted, it can suppress that the paper P is bent rapidly by the guide part 71a of the paper guide member 71, and can suppress that a wrinkle arises in the paper P. Become.

When a paper jam occurs, the switching lever 82 is pushed up to switch the fixing device 20 from the pressure state to the release state, as shown in FIGS. 8 and 10. The contact portion 82a is separated from the bent portion 71b of the paper guide member 71. Thereby, the pressing of the guide portion 71a against the pressing member 93 in the paper guide member 71 is released, and as shown in FIGS. 10 (b) and 12 (a), both end portions in the width direction of the guide portion 71a are pressed members. Separate from 93. And the distance of the width direction both ends and the pressurization member 22 in the guide part 71a becomes large compared with a pressurization state because the width direction both ends of the guide part 71a are spaced apart from the pressing member 93.
Therefore, compared with the case where this configuration is not adopted, the contact between the paper guide member 71 and the pressure member 22 is suppressed in the released state, and the pressure member 22 can be prevented from being damaged. .

[Embodiment 3]
Subsequently, Embodiment 3 of the present invention will be described. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol as Embodiment 1 is used, and detailed description is abbreviate | omitted here.
FIG. 13 is a perspective view of the fixing device 20 in the released state according to the third embodiment. FIG. 14 is a perspective view of the fixing device 20 in a pressurized state according to the third embodiment.
As shown in FIGS. 13 and 14, the fixing device 20 according to the present embodiment includes a fixing roll 21 as an example of a fixing member, a pressure member 22, a sheet guide member 71 as an example of a guide member, and a frame. 81 and a switching lever 82 as an example of setting means and deformation means.

As shown in FIG. 13, the sheet guide member 71 of the present embodiment has a plate shape extending from one end in the width direction toward the other end in the width direction. Similarly to the first embodiment, the paper guide member 71 is provided along the paper transport direction so that one surface faces the fixing roll 21 and the other surface faces the pressure member 22. The end on the downstream side in the transport direction faces the nip N (see FIG. 6 and the like).
Furthermore, the paper guide member 71 of the present embodiment is formed so that the width gradually increases from the upstream side in the paper transport direction to the downstream side in the paper transport direction. As a result, inclined portions 71c extending at an inclination with respect to the paper transport direction are provided at both ends in the width direction of the paper guide member 71.
The sheet guide member 71 of the present embodiment is configured such that its shape changes between the released state and the pressurized state. The shape of the sheet guide member 71 in the released state and the pressurized state will be described later.

The switching lever 82 of the present embodiment is provided on the frame 81 so that it can be pushed down or pushed up at both ends in the width direction of the fixing device 20. As shown in FIG. 13, the switching lever 82 of the present embodiment has a protruding portion 82b that protrudes toward the paper guide member 71 side.
Then, the switching lever 82 according to the present embodiment moves down the predetermined direction in the same manner as in the first embodiment, or moves the position of the pressure member 22 relative to the fixing roll 21 by being pushed up. As a result, the switching lever 82 switches the contact state between the fixing roll 21 and the pressure member 22 between a pressure state and a release state.
Further, as shown in FIG. 14, the switching lever 82 of the present embodiment is configured such that, in a pressurized state, the protruding portion 82 b contacts the inclined portion 71 c of the paper guide member 71 and presses the paper guide member 71. The sheet guide member 71 is elastically deformed.

  Subsequently, the configuration of the sheet guide member 71 in each of the released state and the pressurized state will be described. FIG. 15 is a diagram of the fixing device 20 according to the present embodiment as viewed from the upstream side in the paper conveyance direction. FIG. 15A shows the fixing device 20 in the released state, and FIG. 15B shows the fixing device 20 in the pressurized state. FIG. 16 is a view of the end portion in the width direction of the fixing device 20 in the pressurized state as viewed from the upstream side in the sheet conveyance direction.

First, the configuration of the sheet guide member 71 in the released state will be described.
As shown in FIGS. 13 and 15A, in the released state, the switching lever 82 is pushed up, and the protruding portion 82 b of the switching lever 82 is separated from the paper guide member 71. Yes. As a result, in the released state, the sheet guide member 71 does not receive the pressing force from the protrusion 82b of the switching lever 82, and as shown in FIG. The shape is substantially horizontal along the width direction.

Next, the configuration of the paper guide member 71 in the pressurized state will be described.
In this embodiment, when the switching lever 82 is pushed down to switch the fixing device 20 from the released state to the pressurized state, the protruding portion 82b of the switching lever 82 is inclined to the sheet guide member 71 as shown in FIG. The sheet 71 comes into contact with the portion 71c from the end in the width direction, and the sheet guide member 71 is pressed from the end in the width direction via the inclined portion 71c.
Then, the protrusion 82b of the switching lever 82 comes into contact with the inclined portion 71c of the paper guide member 71 and presses the paper guide member 71, so that the end portion in the width direction with respect to the paper guide member 71 is shown in FIG. Force toward the center in the width direction works. As a result, as shown in FIG. 15B, the central portion in the width direction of the sheet guide member 71 is elastically deformed so as to be recessed toward the fixing roll 21 (see FIG. 14).
Accordingly, the sheet guide member 71 of the present embodiment has a curved shape following the nip portion N (see FIG. 6 and the like) formed between the fixing roll 21 and the pressure member 22 in the pressure state. ing.

  Since the sheet guide member 71 has such a configuration in the pressurized state, the sheet P is conveyed toward the nip portion N while being deformed following the shape of the sheet guide member 71 in the fixing operation. That is, the paper P is guided to the nip portion N in a state where the shape of the front side in the transport direction of the paper P is equal to the shape of the inlet portion of the nip portion N. Thereby, compared with the case where this configuration is not adopted, the paper P is easily inserted into the nip portion N, and the paper P can be prevented from colliding with the fixing roll 21 and the pressure member 22. Then, it is possible to suppress the generation of wrinkles on the paper P and the adhesion of dirt to the paper P due to the paper P colliding with the fixing roll 21 and the pressure member 22.

In this embodiment, as shown in FIGS. 13 and 15, the inclined portion 71c of the paper guide member 71 is inclined toward the end in the width direction from the upstream side in the paper transport direction to the downstream side in the paper transport direction. It has a shape. Accordingly, when the switching lever 82 is pushed down to switch from the released state to the pressurized state, and the protruding portion 82b of the switching lever 82 is brought into contact with the inclined portion 71c of the paper guiding member 71, the paper guiding member 71 is From the upstream side in the paper conveyance direction to the downstream side in the paper conveyance direction, the curve is deformed so as to gradually increase.
Therefore, in the present embodiment, the sheet guide member 71 is deformed in such a shape, so that the sheet P guided by the sheet guide member 71 gradually increases from the upstream side in the sheet transport direction to the downstream side in the sheet transport direction. Then, it will be deformed into a curved shape. Thereby, compared with the case where this structure is not employ | adopted, it can suppress that the paper P is bent rapidly by the guide part 71a of the paper guide member 71, and can suppress that a wrinkle arises in the paper P. Become.

When a paper jam occurs or the like, the switching lever 82 is pushed up to switch the fixing device 20 from the pressure state to the release state, as shown in FIGS. 13 and 15A. The protruding portion 82 b of the switching lever 82 is separated from the inclined portion 71 c of the paper guide member 71. As a result, the pressure from the protruding portion 82b of the switching lever 82 on the paper guide member 71 is released, and the paper guide member 71 is released from the state of being elastically deformed so that the central portion in the width direction protrudes toward the fixing roll 21 side. As a result, it becomes a substantially horizontal state along the width direction. Then, the sheet guide member 71 is in a substantially horizontal state along the width direction, so that the sheet guide member 71 is fixed to the central portion in the width direction of the sheet guide member 71 as compared with a state in which the sheet guide member 71 is elastically deformed in the pressurized state. The distance from the roll 21 is increased.
Therefore, compared with the case where this configuration is not adopted, it is possible to suppress contact between the sheet guide member 71 and the fixing roll 21 in the released state, and to prevent the fixing roll 21 from being damaged.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 20 ... Fixing apparatus, 21 ... Fixing roll, 22 ... Pressure member, 71 ... Paper guide member, 81 ... Frame, 82 ... Switching lever, 91 ... Abutting member, 92 ... Positioning member, 93 ... Pressing member, 100 ... image forming unit, P ... paper, YR ... paper transport path, YS ... paper stacking unit

Claims (6)

A fixing member that is rotatably provided, extends from one end to the other along the rotation axis, and elastically deforms;
By pressing the fixing member, the fixing member is elastically deformed so that the central portion in the rotation axis direction of the pressed fixing member is concave or convex, and a recording material is passed between the fixing member and the fixing member. A pressure member for forming a fixing nip portion for fixing the toner image on the recording material;
It is provided upstream of the fixing nip portion in the recording material conveyance direction, and has a shape in which the central portion in the rotational axis direction is concave or convex in accordance with the shape of the fixing member elastically deformed by the pressure member. And a guide member that guides the recording material toward the fixing nip portion. Setting means for setting the pressure member to a pressure state in which the fixing member is pressed and elastically deformed and a release state in which the pressure on the fixing member is released;
When the pressure member is set in the pressure state by the setting means, the guide member is deformed so that the central portion in the rotation axis direction is concave or convex according to the shape of the fixing member. The fixing device according to claim 1, further comprising: means.   3. The deforming unit separates the guide member from the fixing member and / or the pressing member when the pressing member is set in the released state by the setting unit. The fixing device described. A counter member provided to face the guide member;
The pressure member elastically deforms the fixing member so that the central portion of the fixing member in the rotation axis direction is concave,
The said deformation | transformation means deform | transforms the said guide member so that the said rotation axis direction center part may become concave by making the said opposing member and the said guide member contact. Fixing device. The pressure member elastically deforms the fixing member so that the central portion in the rotation axis direction of the fixing member is concave,
The deforming means is configured to deform the guide member so that the central portion in the rotational axis direction is concave by pressing both end portions in the rotational axis direction of the guide member toward the central portion in the rotational axis direction. The fixing device according to claim 2 or 3. Toner image forming means for forming a toner image;
Transfer means for transferring the toner image formed by the toner image forming means onto a recording material;
Fixing means for fixing the toner image transferred onto the recording material by the transfer means to the recording material;
The fixing means is
A fixing member that is rotatably provided, extends from one end to the other along the rotation axis, and elastically deforms;
By pressing the fixing member, the fixing member is elastically deformed so that the central portion in the rotation axis direction of the pressed fixing member is concave or convex, and a recording material is passed between the fixing member and the fixing member. A pressure member for forming a fixing nip portion for fixing the toner image on the recording material;
It is provided upstream of the fixing nip portion in the recording material conveyance direction, and has a shape in which the central portion in the rotational axis direction is concave or convex in accordance with the shape of the fixing member elastically deformed by the pressure member. And a guide member that guides the recording material toward the fixing nip portion.

Images