JP6424675B2 - Fixing device and image forming apparatus - Google Patents

Description

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

  According to the prior art described in the publication, an endless belt is disposed along the axis of rotation of the rotating body on the inner circumferential side of the endless belt, and the endless belt rotates while sandwiching the recording medium between the rotating body and the rotating body. There is a fixing device provided with a pressing member that applies pressure to a rotating body (see Patent Document 1).

JP, 2014-191039, A

Here, in the case of adopting a configuration in which the endless belt is disposed opposite to the rotating body and a pressing member is provided to press the endless belt from the inside of the endless belt toward the rotating body, the rotation is performed by the pressing member. In the fixing nip portion formed between the body and the endless belt, the force applied to the endless belt may cause the endless belt to wrinkle. In the case where a pressing member for pressing the endless belt from the inside of the endless belt toward the rotating body is further provided upstream of the fixing nip in the rotational direction of the endless belt, the endless belt is endless at the fixing nip. Wrinkles on the belt may be more pronounced. When the endless belt passing through the fixing nip is wrinkled, the recording material passing through the fixing nip may also be wrinkled.
An object of the present invention is to suppress the occurrence of wrinkles in a recording material after fixing.

The invention according to claim 1 comprises a rotatable rotating body, an endless belt which has an outer peripheral surface and an inner peripheral surface and is rotatable, and the outer peripheral surface is disposed to face the rotating body, and A first nip portion is provided inside the inner circumferential surface, and pressing the outer circumferential surface against the rotating body forms a first nip portion through which the recording material holding an image passes between the endless belt and the rotating body. The pressing member and the inner circumferential surface are provided on the inner side of the inner circumferential surface on the upstream side in the recording material conveyance direction than the first nip portion, and the outer circumferential surface is used as the rotating body under a pressure weaker than the first pressing member. By pressing, a second pressing member that forms a second nip portion through which the recording material passes before the first nip portion between the endless belt and the rotating body, and the second nip portion Provided on the inner side of the inner circumferential surface on the upstream side in the transport direction, the outer periphery A contact member that contacts the inner circumferential surface so as not to contact the rotating body, and forms a contact portion whose length in the transport direction increases from the center to the both ends in the direction intersecting the transport direction; A fixing device including
The invention according to claim 2 is the fixing device according to claim 1, wherein the second pressing member is made of a material having a higher elasticity than the first pressing member.
The invention according to claim 3 is the fixing device according to claim 1 or 2, wherein a pressure member in which the first pressing member and the contact member are integrated is configured.
The invention according to claim 4 is the fixing device according to claim 3, wherein the second pressing member is attached to the pressure member.
The invention according to claim 5 is the fixing according to any one of claims 1 to 4, wherein the upstream end or the downstream end of the contact portion in the transport direction has a curved shape. It is an apparatus.
The invention according to claim 6 comprises an image forming unit for forming an image on a recording material, and a fixing device for fixing an image on the recording material on which the image is formed by the image forming unit to the recording material, The device has a rotatable rotating body, an endless belt having an outer circumferential surface and an inner circumferential surface and rotatable, the outer circumferential surface being disposed to face the rotating body, and an inner side of the inner circumferential surface A first pressing member that is provided on the outer circumferential surface to press the outer circumferential surface against the rotating body to form a first nip portion through which a recording material holding an image passes between the endless belt and the rotating body; The inner peripheral surface is provided on the upstream side of the recording material conveyance direction with respect to the first nip portion, and the outer peripheral surface is pressed against the rotating body with a pressure weaker than that of the first pressing member. The first nip portion between the endless belt and the rotating body And a second pressing member forming a second nip portion through which the recording material passes before the inner circumferential surface on the upstream side of the transport direction with respect to the second nip portion, and the outer circumferential surface A contact member that contacts the inner circumferential surface so as not to contact the rotating body, and forms a contact portion whose length in the transport direction increases from the center to the both ends in the direction intersecting the transport direction; It is an image forming apparatus characterized by including.

According to the first aspect of the invention, the occurrence of wrinkles in the recording material after fixing can be suppressed.
According to the second aspect of the invention, it is possible to suppress the deviation of the image on the recording material when fixing is performed.
According to the third aspect of the present invention, the structure can be simplified, and the positioning of the contact member with respect to the first pressing member can be appropriately performed.
According to the fourth aspect of the present invention, it is possible to properly position the second pressing member relative to the first pressing member and the contact member.
According to the fifth aspect of the present invention, the occurrence of wrinkles in the recording material after fixing can be suppressed more smoothly.
According to the sixth aspect of the invention, the occurrence of wrinkles in the recording material after fixing can be suppressed.

FIG. 1 is a diagram showing an example of the entire configuration of an image forming apparatus. FIG. 2 is a diagram for describing a configuration of a fixing device. It is a perspective view showing the composition of a pressurization member. It is a side view showing composition of a pressurization member. It is a figure for demonstrating the press part in a pressure member. (A)-(d) is a figure which shows the other structural example of a pressing part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
FIG. 1 is a view showing an example of the entire configuration of an image forming apparatus 1 to which the present embodiment is applied. Here, FIG. 1 shows a cross-sectional configuration when the image forming apparatus 1 is viewed from the front side.

The image forming apparatus 1 includes an image forming unit 10, an intermediate transfer belt 20, a secondary transfer device 30, a sheet supply unit 40, a fixing device 50, and a control unit 60.
The image forming unit 10 forms an image using toner. Further, the image formed by the image forming unit 10 is primarily transferred to the intermediate transfer belt 20. Further, the secondary transfer device 30 secondarily transfers the image primarily transferred to the intermediate transfer belt 20 to the sheet P. Furthermore, the sheet supply unit 40 supplies the sheet P toward the secondary transfer device 30. In addition, the fixing device 50 fixes the image secondarily transferred onto the sheet P by the secondary transfer device 30. Then, the control unit 60 controls the operation of each unit constituting the image forming apparatus 1.

  The image forming unit 10 includes four image forming units 10Y, 10M, 10C, and 10K that form toner images of respective color components by an electrophotographic method. The image forming units 10Y, 10M, 10C, and 10K are arranged side by side so as to face the intermediate transfer belt 20. The four image forming units 10Y, 10M, 10C, and 10K form yellow, magenta, cyan, and black images, respectively.

The image forming units 10Y, 10M, 10C, and 10K each include a photosensitive drum 11, a charging device 12, an exposure device 13, a developing device 14, a primary transfer device 15, and a drum cleaning device 16.
The photosensitive drum 11 is disposed to face the intermediate transfer belt 20, and rotates in the direction indicated by the arrow in the figure. The charging device 12, the exposure device 13, the developing device 14, the primary transfer device 15 and the drum cleaning device 16 are arranged around the photosensitive drum 11 in this order along the direction of the arrow. Here, the charging device 12 charges a photosensitive layer (not shown) provided on the outer peripheral surface of the photosensitive drum 11 to a predetermined potential. Further, the exposure device 13 selectively exposes the charged photosensitive layer of the photosensitive drum 11 to form an electrostatic latent image. Further, the developing device 14 develops the electrostatic latent image formed on the photosensitive drum 11 with the toner of the corresponding color. Furthermore, the primary transfer device 15 is disposed at a position facing the photosensitive drum 11 with the intermediate transfer belt 20 interposed therebetween. The primary transfer device 15 primarily transfers the toner image developed on the photosensitive drum 11 to the intermediate transfer belt 20. The drum cleaning device 16 cleans the remaining toner remaining on the photosensitive drum 11 after the primary transfer.

  The intermediate transfer belt 20 is stretched around two rotatably provided roll members 21 and 22 and rotates in a direction indicated by an arrow in the figure. Here, the roll member 21 rotationally drives the intermediate transfer belt 20. In addition, the roll member 22 is disposed to face the secondary transfer roll 31 with the intermediate transfer belt 20 interposed therebetween. The roll member 22 and the secondary transfer roll 31 constitute a secondary transfer device 30. A belt cleaning device (not shown) for cleaning residual toner remaining on the intermediate transfer belt 20 after secondary transfer is provided at a position facing the roll member 21 with the intermediate transfer belt 20 interposed therebetween.

  The sheet supply unit 40 includes a sheet storage unit 41, a supply roll 42, a conveyance path 43, and a plurality of conveyance rolls 44. The sheet storage unit 41 is disposed below the image forming unit 10 and stores the sheet P as an example of a recording material used in the image forming apparatus 1. The supply roll 42 feeds and supplies sheets P stored in the sheet storage unit 41 one by one. The conveyance path 43 is provided so as to extend from the sheet storage unit 41 to a sheet discharge stacking unit provided above the image forming apparatus 1 via the secondary transfer device 30 and the fixing device 50. The plurality of transport rolls 44 transport the sheet P in the transport path 43 along the transport direction A from the lower side to the upper side in the drawing.

  The fixing device 50 includes a heating module 51 and a pressure module 52. The heating module 51 and the pressure module 52 are disposed to face each other with the transport path 43 interposed therebetween. In this example, the heating module 51 is disposed below the transport path 43, and the pressure module 52 is disposed above the transport path 43. The heating module 51 contacts one side of the sheet P conveyed along the conveyance direction A to heat the sheet P. The pressure module 52 contacts the other side of the sheet P conveyed along the conveyance direction A, and applies pressure to the sheet P together with the heating module 51. Here, the heating module 51 is disposed to face the surface (one surface) facing the intermediate transfer belt 20 (roll member 22) when passing through the secondary transfer device 30 in the sheet P. Ru. On the other hand, the pressure module 52 is disposed to face the surface (the other surface) of the sheet P facing the secondary transfer roll 31 when passing through the secondary transfer device 30. The details of the fixing device 50 will be described later.

Now, an image forming operation using the image forming apparatus 1 shown in FIG. 1 will be described.
When image information is received from an external device (not shown), the control unit 60 creates exposure data based on the image information and outputs it to each exposure device 13 in the image forming unit 10. Further, the control unit 60 outputs a control signal of operation start to each unit constituting the image forming apparatus 1.

  Then, for example, in the image forming unit 10Y for yellow, the photosensitive drum 11 which is rotationally driven in the direction of the arrow in the figure is charged by the charging device 12, and the exposure device 13 emits light based on the exposure data supplied from the control unit 60. Exposure. As a result, an electrostatic latent image related to the yellow image is formed on the photosensitive drum 11. The electrostatic latent image formed on the photosensitive drum 11 is developed by the developing device 14 with yellow toner. As a result, a yellow toner image is formed on the photosensitive drum 11. Similarly, in the other image forming units 10M, 10C, and 10K, toner images of magenta (M), cyan (C), and black (K) are formed in the above-described procedure, respectively.

  The toner images formed on the photosensitive drums 11 of the image forming units 10Y, 10M, 10C, and 10K are primarily transferred onto the intermediate transfer belt 20 by the primary transfer devices 15 provided thereon. Along with this, on the intermediate transfer belt 20, toner images of respective colors are superimposed. The superimposed toner image on the intermediate transfer belt 20 is directed to a secondary transfer position where the secondary transfer device 30 is provided as the intermediate transfer belt 20 rotates. The residual toner remaining on each photosensitive drum 11 after the primary transfer is removed by the corresponding drum cleaning device 16.

  On the other hand, in the sheet supply unit 40, the sheets P stored in the sheet storage unit 41 are taken out sheet by sheet using the supply roll 42 and sent out to the transport path 43. After that, the transport roll 44 provided in the transport path 43 is adjusted to match the timing when the superimposed toner image on the intermediate transfer belt 20 reaches the secondary transfer position, the sheet P sent from the sheet storage unit 41. Transport to the next transfer position.

  Then, the superimposed toner image on the intermediate transfer belt 20 is secondarily transferred by the secondary transfer device 30 onto the sheet P passing the secondary transfer position. At this time, secondary transfer of the superimposed toner image is performed on one side of the sheet P facing the intermediate transfer belt 20.

  Thereafter, the sheet P on which the superimposed toner image has been transferred by passing the secondary transfer position passes the fixing device 50. At this time, one side of the sheet P (the transferred surface of the superimposed toner image) is heated by the heating module 51. Further, the sheet P is pressurized by being sandwiched between the heating module 51 and the pressure module 52. As a result, the superimposed toner image is fixed on the sheet P. Then, the sheet P on which the superimposed toner image is fixed by passing through the fixing device 50 is discharged to a sheet discharge stacking unit provided on the upper portion of the image forming apparatus 1. Further, residual toner remaining on the intermediate transfer belt 20 after passing the secondary transfer position is removed by a belt cleaning device (not shown).

FIG. 2 is a diagram for explaining the configuration of the fixing device 50. As shown in FIG.
The fixing device 50 according to the present embodiment includes the heating module 51 and the pressure module 52 as described above. The fixing device 50 is detachably provided to the image forming apparatus 1.

  The heating module 51 is provided with a heating roll 510 which is formed in a cylindrical shape and rotates in the arrow B direction. Further, the pressure module 52 is provided with a pressure belt 520 which is formed endlessly and which rotates in the arrow C direction. The heating roller 510 and the pressure belt 520 contact with each other while being applied pressure to form a fixing nip portion NF.

  The heating roll 510 as an example of a rotating body has a cylindrical member made of a metal pipe, and a heating element (both not shown) disposed inside the cylindrical member to heat the cylindrical member. In addition, on the outer peripheral surface of the cylindrical member in the heating roller 510, a covering member (not shown) for covering the outer peripheral surface with rubber or the like is provided. The heating roller 510 is rotationally driven from the outside by a driving source (not shown).

  On the other hand, the pressure module 52 has the pressure belt 520 described above, a pressure member 521, a pressure pad 522, a support member 523 and a belt guide 524.

  The pressure belt 520 as an example of an endless belt has an endless belt-like shape, and nips and presses the sheet P passing through the fixing nip portion NF with the heating roller 510. Therefore, pressure belt 520 has an outer peripheral surface facing heating roller 510 and forming fixing nip portion NF, and an inner peripheral surface which is the back surface of the outer peripheral surface. Here, the pressure belt 520 is adapted to be rotated (followed and rotated) by the heating roller 510 that is rotationally driven. The pressure belt 520 is formed, for example, by forming a releasing layer made of fluorocarbon resin on the surface of a belt base material formed in a thin cylindrical shape from a synthetic resin such as polyimide.

  The pressure member 521 is disposed on the inside of the pressure belt 520 at a position facing the heating roller 510 with the pressure belt 520 interposed therebetween. The pressing member 521 presses the pressing belt 520 against the heating roll 510 via the inner circumferential surface of the pressing belt 520, whereby the fixing nip portion NF where the heating roll 510 and the pressing belt 520 are nipped is provided. Let it form. The pressure member 521 is formed to extend upstream of the fixing nip portion NF in the rotational direction (the direction of the arrow C) of the pressure belt 520. Further, on the upstream side of the fixing nip portion NF in the transport direction A, a pressing pad 522 is provided at a position facing the inner circumferential surface of the pressure belt 520. The pressing pad 522 is formed of, for example, a felt extending along a direction orthogonal to the transport direction A. The pressing pad 522 may be made of an elastic body having higher elasticity than the pressing member 521, and silicon rubber or the like may be used in addition to felt. The pressing pad 522 is attached to the pressing member 521 by adhesion, for example. The pressing pad 522 of the present embodiment presses the pressing belt 520 against the heating roll 510 via the inner circumferential surface of the pressing belt 520 to heat the sheet upstream of the fixing nip portion NF in the transport direction A. A pre-nip portion NP where the roll 510 and the pressure belt 520 are nipped is formed. Here, the pressure applied to the pre-nip portion NP is set smaller than the pressure applied to the fixing nip portion NF. In the present embodiment, the fixing nip portion NF is an example of a first nip portion, and the pre-nip portion NP is an example of a second nip portion.

  Further, the pressing member 521 presses the inner peripheral surface of the pressing belt 520 on the upstream side of the pre-nip portion NP in the transport direction A, thereby bringing the contact portion CO where the pressing belt 520 and the pressing member 521 contact. Let it form. However, in the contact portion CO, unlike the fixing nip portion NF and the pre-nip portion NP described above, the pressure belt 520 and the heating roll 510 are not in contact with each other.

  The support member 523 is attached to the back side of the pressure member 521 as viewed from the fixing nip portion NF. The support member 523 supports the pressure member 521 on the inner side of the pressure belt 520 and presses the pressure belt 520 toward the heating roller 510.

  The belt guides 524 are respectively provided on both end sides of the pressure belt 520 along the circumferential path of the pressure belt 520. The belt guide 524 abuts on the end of the rotating pressure belt 520 to suppress the meandering of the pressure belt 520.

Next, the configuration of the pressure member 521 will be described more specifically.
FIG. 3 is a perspective view showing the configuration of the pressure member 521. As shown in FIG. 4 is a side view showing the configuration of the pressure member 521. As shown in FIG.

  The pressing member 521 includes a pressing portion 5211, a pressing pad storage portion 5212, a pressing portion 5213, a support member mounting portion 5214, a first protruding portion 5215, and a second protruding portion 5216. Here, the pressing unit 5211, the pressing pad housing unit 5212 and the pressing unit 5213 are provided on the upper surface side of the pressing member 521 (the side facing the inner circumferential surface of the pressing belt 520). On the other hand, the support member mounting portion 5214, the first protrusion 5215, and the second protrusion 5216 are provided on the back side of the pressing member 521. The pressing member 521 of the present embodiment is made of a resin that is harder and has lower elasticity than the felt that constitutes the pressing pad 522 described above.

  The pressing unit 5211 as an example of the first pressing member is located on the most downstream side as viewed from the conveyance direction A. The pressing unit 5211 is used to form the fixing nip portion NF when the fixing unit 50 is mounted.

  Next, the pressing pad storage portion 5212 is located on the upstream side of the pressing portion 5211 as viewed in the conveyance direction A. Here, the pressing pad housing portion 5212 is formed in a concave shape, and the pressing pad 522 (see FIG. 2) is housed and attached to this portion. The pressing pad 522 attached to the pressing pad accommodation portion 5212 is used to form the pre-nip portion NP when the pressing pad 522 is attached to the fixing device 50. Here, in the present embodiment, the pressing pad 522 has a function as an example of the second pressing member.

  The pressing portion 5213 as an example of the contact member is located upstream of the pressing pad storage portion 5212 as viewed in the conveyance direction A. The shape of the pressing portion 5213 will be described later.

  The supporting member mounting portion 5214 is located on the most downstream side as viewed in the conveyance direction A. In addition, the support member mounting portion 5214 is formed of a groove extending along a direction orthogonal to the conveyance direction A. Then, one end of the support member 523 is inserted into and fixed to the support member mounting portion 5214.

  The first projecting portion 5215 is located on the upstream side of the support member mounting portion 5214 as viewed in the conveyance direction A. In addition, the second protrusion 5216 is located upstream of the first protrusion 5215 as viewed in the conveyance direction A. The first projecting portion 5215 and the second projecting portion 5216 are formed of ridges extending along a direction orthogonal to the conveyance direction A.

  FIG. 5 is a view for explaining the pressing portion 5213 in the pressing member 521. As shown in FIG. Here, FIG. 5 shows a top view of the pressing portion 5213 as viewed from above.

  In the present embodiment, pressing portion 5213 extends in the direction orthogonal to conveyance direction A. Further, in the pressing portion 5213, a central length Lc, which is the transport direction length of the central portion in a direction orthogonal to the transport direction A, and an end length Le, which is the transport length of both ends, are different. More specifically, the central portion length Lc of the pressing portion 5213 is set smaller than the end portion length Le. Further, in the pressing portion 5213, the upstream side in the transport direction A is formed by a curve, and the downstream side in the transport direction A is formed by a straight line. Thus, in the pressing portion 5213, the length in the conveyance direction A increases from the center to the both ends in the direction orthogonal to the conveyance direction A.

Now, the behavior of the pressure belt 520 in the fixing device 50 and the behavior of the sheet P passing through the fixing device 50 will be described.
In the present embodiment, the pressure belt 520 is rotated in the direction of arrow C by receiving the driving force from the heating roll 510 that is rotationally driven in the direction of arrow B. In this case, the pressure portion 5211 and the pressure portion 5213 provided on the pressure member 521 are in contact with the inner peripheral surface of the pressure belt 520, and the pressure pad 522 attached to the pressure member 521 is in contact Do.

  At this time, in the fixing nip portion NF, the pressing portion 5211 applies a force to draw the pressing belt 520 rotating in the arrow C direction from both ends to the central portion in the direction orthogonal to the arrow C direction. In addition, also in the pre-nip portion NP, the pressing pad 522 applies a force to draw the pressing belt 520 rotating in the arrow C direction from both ends to the central portion in the direction orthogonal to the arrow C direction. Then, when the pressure belt 520 is actually moved from the both ends to the center with the application of such a force, the pressure belt 520 itself is wrinkled. Then, the paper P passing through the pre-nip portion NP and the fixing nip portion NF has a wrinkle (paper wrinkle) caused by the pressure belt 520.

  On the other hand, in the present embodiment, the configuration of the pressing portion 5213 contacting the inner circumferential surface of the pressure belt 520 on the upstream side of the fixing nip portion NF and the pre-nip portion NP in the arrow C (conveying direction A) is It is shown in FIG. Thus, in the contact portion CO, the pressing portion 5213 applies a force from the central portion to both ends in the direction orthogonal to the arrow C direction, with respect to the pressure belt 520 rotating in the arrow C direction. As a result, since the forces are offset at the pre-nip portion NP and the fixing nip portion NF located downstream in the direction of the arrow C, the pressure belt 520 is wrinkled at the pre-nip portion NP and the fixing nip portion NF. It can be suppressed. Therefore, it is possible to suppress the occurrence of wrinkles on the sheet P passing through the fixing device 50.

  In the present embodiment, as shown in FIG. 5, the upstream side of the conveyance direction A in the pressing portion 5213 has a curved shape, and the downstream side of the conveyance direction A has a linear shape. However, the shape of the pressing portion 5213 is not limited to this.

FIG. 6 is a view showing another configuration example of the pressing portion 5213. As shown in FIG.
Here, FIG. 6A shows a first modification of the pressing portion 5213. As shown in FIG. As shown in FIG. 6A, the upstream side of the conveyance direction A in the pressing portion 5213 may be linear, and the downstream side of the conveyance direction A may be curved.
Moreover, FIG.6 (b) has shown the 2nd modification of the pressing part 5213. As shown in FIG. As shown in FIG. 6B, both of the upstream side and the downstream side in the conveyance direction A in the pressing portion 5213 may have a curved shape.
Further, FIG. 6C shows a third modification of the pressing portion 5213. As shown in FIG. 6C, the upstream side of the conveyance direction A in the pressing portion 5213 may be formed into a V shape formed of two straight lines, and the downstream side of the conveyance direction A may be linear.
Furthermore, FIG. 6D shows a fourth modification of the pressing portion 5213. As shown in FIG. 6D, the upstream side in the conveyance direction A in the pressing portion 5213 may be formed in a step shape formed of a plurality of straight lines, and the downstream side in the conveyance direction A may be linear.
And about the structure shown to FIG.6 (c) and FIG.6 (d), you may replace the upstream and downstream of the conveyance direction A. FIG.

  Further, in the present embodiment, the fixing nip portion NF and the contact portion CO are formed by using one pressing member 521, but the present invention is not limited to this. For example, the fixing nip portion NF may be formed using a certain member, and the contact portion CO may be formed using another member. However, when the configuration of the present embodiment is adopted, it is possible to improve the positioning accuracy of the contact portion CO with respect to the fixing nip portion NF.

  Furthermore, in the present embodiment, the pressing pad 522 for forming the pre-nip portion NP is attached to the pressing member 521, but the pressing pad 522 may be attached to a member other than the pressing member 521. However, when the configuration of the present embodiment is adopted, it is possible to improve the positioning accuracy of the pre-nip portion NP with respect to the fixing nip portion NF.

Reference Signs List 1 image forming apparatus 10 image forming unit 20 intermediate transfer belt 30 secondary transfer device 40 sheet feeding unit 50 fixing device 51 heating module 52 pressure module 60 control 5, 510: heating roll, 520: pressure belt, 521: pressure member, 522: pressure pad, 523: support member, 524: belt guide, 5211, pressure portion, 5212: pressure pad housing portion, 5213: pressing Part, 5214 ... Support member mounting part, 5215 ... First projection, 5216 ... Second projection, P ... Paper

Claims (6)

A rotatable body, and
An endless belt having an outer circumferential surface and an inner circumferential surface and rotatable, the outer circumferential surface being disposed to face the rotating body;
It is provided inside the inner peripheral surface, and by pressing the outer peripheral surface against the rotating body, a first nip portion is formed between the endless belt and the rotating body, through which the recording material holding the image passes. A first pressing member,
The inner peripheral surface is provided on the upstream side of the recording material conveyance direction with respect to the first nip portion, and the outer peripheral surface is pressed against the rotating body with a pressure weaker than that of the first pressing member. A second pressing member forming a second nip portion through which the recording material passes before the first nip portion, between the endless belt and the rotating body;
It is provided on the inner side of the inner circumferential surface on the upstream side of the second nip portion in the transport direction, and the outer circumferential surface contacts the inner circumferential surface so as not to contact the rotating body and intersects the transport direction A fixing device comprising: a contact member forming a contact portion whose length in the transport direction increases from the center portion of the direction toward the both end portions.   The fixing device according to claim 1, wherein the second pressing member is made of a material having a higher elasticity than the first pressing member.   The fixing device according to claim 1, wherein a pressure member in which the first pressing member and the contact member are integrated is configured.   The fixing device according to claim 3, wherein the second pressing member is attached to the pressing member.   The fixing device according to any one of claims 1 to 4, wherein an upstream end or a downstream end of the contact portion in the transport direction has a curved shape. An image forming unit that forms an image on a recording material;
A fixing device for fixing the image on the recording material on which the image formation has been performed by the image forming unit to the recording material;
The fixing device is
A rotatable body, and
An endless belt having an outer circumferential surface and an inner circumferential surface and rotatable, the outer circumferential surface being disposed to face the rotating body;
It is provided inside the inner peripheral surface, and by pressing the outer peripheral surface against the rotating body, a first nip portion is formed between the endless belt and the rotating body, through which the recording material holding the image passes. A first pressing member,
The inner peripheral surface is provided on the upstream side of the recording material conveyance direction with respect to the first nip portion, and the outer peripheral surface is pressed against the rotating body with a pressure weaker than that of the first pressing member. A second pressing member forming a second nip portion through which the recording material passes before the first nip portion, between the endless belt and the rotating body;
It is provided on the inner side of the inner circumferential surface on the upstream side of the second nip portion in the transport direction, and the outer circumferential surface contacts the inner circumferential surface so as not to contact the rotating body and intersects the transport direction An image forming apparatus comprising: a contact member forming a contact portion whose length in the transport direction increases from a central portion of the direction to both end portions.

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