JP2009210686A - Fixing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of preventing a pressing member from being grasped between a heating roll and a support member for supporting the pressing member, via a belt member, when the pressing member presses the heating roll. <P>SOLUTION: A side wall 112b is provided in a downstream along a belt member traveling direction, in a block 112. A height H1 of a pressing pad 110 is formed to be higher than a height H2 of the side wall 112b. A distance between the side wall 112b and a contact face 110a of the pressing pad 110 is made to get long along with approach to the heating roll 70, when the pressing pad 110 does not press the heating roll 70. The side wall 112b is brought into pressure contact with the contact face 110a of the pressing pad 110, by deforming elastically the pressing pad 110, when the pressing pad 110 presses the heating roll 70. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fixing device having a heating roll, and an image forming apparatus such as a printer, a facsimile, and a copying machine having the fixing device.

For example, Patent Document 1 discloses an image fixing device that includes a heat fixing roll, an endless belt, and a pressing pad, and a lubricant is interposed between the pressing pad and the endless belt.
Further, for example, Patent Document 2 supports a rotatable heating roll, an endless belt that is pressed against the heating roll, an elastic pressing member that presses the endless belt against the heating roll, and one of the elastic pressing members that is variably supported. Disclosed is a fixing device including a movable support member that performs and a drive unit that variably sets the movable support member.
Further, for example, Patent Document 3 includes a heat-fixing roll, an endless belt, a pressing pad, a low friction sheet that is disposed on an urging surface of the pressing pad and is in contact with the endless belt, and is in contact with the endless belt of the low friction sheet. An image fixing device having methylphenyl silicone oil interposed on the surface is disclosed.
Further, for example, Patent Document 4 is arranged on a contact surface between a fixing heat roller, a pressure belt that is externally driven by the fixing heat roller, a pressure member, and a pressure belt of the pressure member. Disclosed is an image fixing device that includes a sliding member that includes a low friction sheet and a lubricant supply sheet, and a guide that includes the lubricant supply member.

JP-A-10-213984 JP-A-10-228200 JP 2004-037764 A JP 2007-187889 A

  The present invention is made from the background described above, and when the pressing member presses the heating roll, the pressing member is interposed between the heating roll and the support member that supports the pressing member via the belt member. It is an object of the present invention to provide a fixing device that can prevent pinching.

  In order to achieve the above object, a fixing device according to the present invention includes a rotatable heating roll, a belt member that travels following the rotation of the heating roll, and an inner side of the belt member. A pressing member that presses the heating roll via a support member, and a support member that supports the pressing member so as to press the pressing member toward the heating roll. The support member is more in the belt member traveling direction than the pressing member. On the downstream side, there is a side wall for regulating the pressing member, and the pressing member does not contact the side wall in a free form, and elastically deforms and contacts the side wall when pressing the heating roll.

  Suitably, the said press member has a part higher than the height of the said side wall at the time of a free shape.

  Preferably, the pressing member presses the heating roll at a portion on the downstream side in the belt traveling direction.

  Preferably, when the pressing member is in a free shape, the distance between the side wall and the downstream surface of the pressing member in the belt member traveling direction becomes longer as the heating roll is approached.

  Preferably, the side wall is formed obliquely with respect to a downstream surface in the belt member traveling direction when the pressing member is in a free shape.

  Preferably, the side wall passes through an edge on the heating roll side of the side wall when the pressing member is in a free shape, and a virtual surface perpendicular to a downstream side surface of the pressing member in the belt member traveling direction, and the pressing The cross-sectional area obtained by cutting the space surrounded by the downstream surface of the member in the belt member traveling direction and the side wall by a plane perpendicular to the rotation axis of the heating roll is increased as the end of the support member is approached. Is formed.

  A second fixing device according to the present invention includes a rotatable heating roll, a belt member that travels following the rotation of the heating roll, and is disposed inside the belt member, and the heating member is interposed via the belt member. A pressing member that presses the roll, and a supporting member that supports the pressing member so as to press the heating member toward the heating roll, and the supporting member is located downstream of the pressing member in the belt member traveling direction. A side wall for regulating the pressing member is provided, and an inclined portion is provided on the downstream side of the pressing member in the belt member traveling direction so that the height decreases as the side wall is approached.

  Suitably, the said press member has a part higher than the height of the said side wall at the time of a free shape.

  Preferably, the pressing member presses the heating roll at a portion on the downstream side in the belt traveling direction.

Preferably, at the time of the free shape of the pressing member, the height of the downstream surface of the pressing member in the belt member traveling direction is equal to or less than the height of the side wall,
When the pressing member presses the heating roll, the height of the side surface of the pressing member on the downstream side in the belt member traveling direction is higher than the height of the side wall.

  Preferably, when the pressing member has a free shape, the difference between the height of the downstream surface of the pressing member in the belt member traveling direction and the height of the side wall increases as the end of the pressing member approaches. Is formed.

  Preferably, the inclined portion is formed of a plurality of surfaces.

  The present invention includes an image forming apparatus having the above-described fixing device.

  According to the present invention, when the pressing member presses the heating roll, the fixing device can prevent the pressing member from being sandwiched between the heating roll and the support member that supports the pressing member via the belt member. Can be provided.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to an embodiment of the present invention.
The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a discharge unit 16 is provided on the upper portion of the image forming apparatus main body 12. For example, two-stage sheet feeding units 18 and 18 can be arranged below the image forming apparatus main body 12.

Each paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which a recording medium such as a sheet is stored. The paper feed cassette 22 is slidably attached to the paper feed unit main body 20 and is pulled out in the front direction (right direction in FIG. 1).
In addition, a pickup roll 24 is disposed in the upper part near the rear end of the paper feed cassette 22, and a retard roll 26 and a feed roll 28 are disposed behind the pickup roll 24.

The conveyance path 32 is a recording medium path from the pickup roll 24 to the discharge port 34 of the lowermost sheet feeding unit 18, and this conveyance path 32 is near the back surface (left side surface in FIG. 1) of the image forming apparatus main body 12. In addition, it has a portion formed substantially vertically from the pickup roll 24 of the lowermost sheet feeding unit 18 to the fixing device 36 described later.
A transfer device 42 and an image carrier 44 described later are disposed on the upstream side of the fixing device 36 in the conveyance path 32, and a resist roll 38 is disposed on the upstream side of the transfer device 42 and the image carrier 44.
Further, a discharge roll 40 is disposed in the vicinity of the discharge port 34 of the conveyance path 32.
Accordingly, the recording medium fed from the paper feed cassette 22 of the paper feed unit 18 by the pickup roll 24 is fed by the retard roll 26 and the feed roll 28 and guided to the transport path 32, and is temporarily stopped by the registration roll 38, The developer image is transferred between a transfer device 42 and an image carrier 44 described later, and the transferred developer image is fixed by the fixing device 36 and discharged from the discharge port 34 by the discharge roll 40. It is discharged to the part 16.

However, in the case of duplex printing, it is returned to the reverse path.
That is, the front side of the discharge roll 40 in the conveyance path 32 is divided into two forks, and a switching claw 46 is provided at the divided portion, and a reverse path 48 is formed from the divided portion to the registration roll 38.
The reversing path 48 is provided with transport rolls 50a to 50c. In the case of double-sided printing, the switching claw 46 is switched to the side that opens the reversing path 48, and the discharge roll 40 is in front of the rear end of the recording medium. At this time, the discharge roll 40 is reversed, the recording medium is guided to the reverse path 48, and is discharged from the discharge port 34 to the discharge unit 16 through the registration roll 38, the transfer device 42, the image carrier 44 and the fixing device 36. It is.

The image forming unit 14 is of an electrophotographic type, and is charged by the image carrier 44 made of a photosensitive member, a charging device 56 made of, for example, a charging roll for uniformly charging the image carrier 44, and the charging device 56. An optical writing device 58 for writing a latent image on the image carrier 44 with light, a developing device 60 having a developing roll so as to visualize the latent image of the image carrier 44 formed by the optical writing device 58 with toner, A transfer device 42 composed of, for example, a transfer roll for transferring a toner image by the developing device 60 to a recording medium, a cleaning device 62 for cleaning the toner remaining on the image carrier 44, and a toner on the recording medium transferred by the transfer device 42 The image forming apparatus includes a fixing device 36 that fixes an image on a recording medium.
The optical writing device 58 includes, for example, a scanning type laser exposure device, and forms a latent image on the image carrier 44 across a process cartridge 64 described later.
The optical writing device 58 may use an LED, a surface emitting laser, or the like as another embodiment.

In the process cartridge 64, the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62 are integrated, and these can be replaced as a unit.
The process cartridge 64 can be removed from the image forming apparatus main body 12 by opening the discharge unit 16.

FIG. 2 shows details of the fixing device 36.
The fixing device 36 includes a heating roll 70, a belt member 72 formed in an endless belt shape, a guide member 74 that rotatably guides the belt member 72, and a belt member 72 that is disposed inside the belt member 72. A pressing unit 76 that presses against the belt 70;
A sliding sheet (not shown) for reducing friction between the belt member 72 and the pressing unit 76 may be provided between the belt member 72 and the pressing unit 76.

The heating roll 70 includes a cylindrical roll portion 84 and a heater 86 disposed in the roll portion 84.
The roll part 84 is supported by a bearing for heating rolls (not shown) so as to be rotatable, and rotates in the arrow A direction.
The roll portion 84 includes a core 88 made of, for example, iron or aluminum, and a release layer 90 coated or applied to the core 88. The core 88 has an outer shape of, for example, 30 mm and a thickness of, for example, 0.7 mm. It is.
The release layer 90 is made of an insulating material having excellent release properties, such as PFA, and has a film thickness of, for example, 20 μm.

A plurality of (for example, five) peeling claws 92 are in contact with the roll portion 84.
The heater 86 is composed of, for example, two lamps.
A thermostat 94 is provided on the opposite side of the heating roll 70 from the belt member 72 so as to face the heating roll 70.

An inlet chute 96 is provided on the upstream side of the nip N. A sheet S that is a recording medium conveyed in the direction of arrow B is guided to the inlet chute 96, and the leading end of the sheet S is guided to the nip N.
An outlet chute 98 is provided on the downstream side of the nip N.

The belt member 72 is provided between the heating roll 70 and the pressing unit 76, and a nip N is formed when the heating roll 70 and the belt member 72 are pressed and contacted by the pressing unit 76. Thus, the sheet S is conveyed.
The belt member 72 travels in the direction of arrow C following the rotation of the heating roll 70 by being in pressure contact with the heating roll 70.
The belt member 72 is formed of, for example, a synthetic resin such as polyimide in an endless belt shape having a thickness of 75 μm, for example, and a release layer made of PFA or the like is provided on the surface.

The pressing unit 76 supports a pressing pad 110 that is a pressing member that presses the heating roll 70 via the belt member 72, a block 112 that is a supporting member that supports the pressing pad 110, and the block 112 and the belt member 72. And a frame 116 that supports the housing 114.
The pressing pad 110 is formed of an elastic body such as LSR (liquid silicone rubber), for example, and the pressing pad 110 presses the heating roll 70 via the belt member 72 (hereinafter, referred to as “when pressed”). It is designed to be elastically deformed.
The block 112 has a substantially U-shaped cross section made of, for example, LCP (liquid crystal polymer) having high heat resistance.
The block 112 presses the pressing pad 110 toward the heating roll 70 side.

The housing 114 is made of a synthetic resin such as PBT (polybutylene terephthalate), for example, and supports the block 112 and presses it toward the heating roll 70 and supports the belt member 72.
The frame 116 has a substantially U-shaped cross section made of metal such as iron or aluminum, and supports the housing 114 and presses it toward the heating roll 70.

3 and 4 show details of the pressing pad 110 and the block 112. FIG. 3 shows a state where the pressing pad 110 is not pressing the heating roll 70, and FIG. 4 shows the pressing pad 110 being a heating roll. The state which is pressing 70 is shown.
In FIG. 4 and subsequent drawings, the description of the belt member 72, the housing 114, and the like is omitted for the sake of specific description and clarification.
Further, in a state where the pressing pad 110 is not pressing the heating roll 70, the pressing pad 110 is in a free-form state that is not elastically deformed (hereinafter, this state is described as “before pressing”). There is).

As shown in FIG. 3, in the heating roll 70, the center of the heating roll (indicated by a one-dot chain line in FIG. 3) is downstream from the center of the pressing pad 110 in the belt member traveling direction (sheet conveyance direction) (FIGS. 3 and 4). It is arranged so that it is in the position of the left side).
By disposing the heating roll 70 and the pressing pad 110 in this manner, the pressure distribution when the pressing pad 110 is pressed becomes stronger on the downstream side in the belt member traveling direction, so that the leading edge of the sheet S is aligned with the nip N. The resistance at the time of entering can be reduced, and the discharge efficiency of the sheet S from the nip N can be increased.

The pressing pad 110 is bonded to the bonding surface 112 a that is the bottom of the concave portion of the block 112.
Further, the block 112 has a side wall 112b on the downstream side in the belt member traveling direction.
As shown in FIG. 4, when the pressing pad 110 is pressed toward the heating roll 70, the side wall 112 b is in pressure contact with the pressing pad 110, so that the position of the pressing pad 110 on the downstream side in the belt member traveling direction is reached. And the unnatural operation of the pressing pad 110 is suppressed.
As a result, the pressure distribution when the pressing pad 110 is pressed can be further stabilized.
Further, as shown in FIG. 3, the height H1 from the adhesive surface 112a of the pressing pad 110 is set to be the adhesive surface 112a of the side wall 112b so that the block 112 and the heating roll 70 do not interfere with each other via the belt member 72 during pressing. Is formed higher than the height H2.

Moreover, as shown in FIG. 3, the side wall 112b has an oblique shape with respect to the contact surface 110a with the side wall 112b of the pressing pad 110, and the pressing pad 110 does not contact the side wall 112b before pressing.
That is, when the pressing pad 110 is not pressing the heating roll 70, the distance between the side wall 112 b and the contact surface 110 a of the pressing pad 110 becomes longer as the heating roll 70 is approached.
When the pressing pad 110 presses the heating roll 70, as shown in FIG. 4A, the pressing pad 110 is elastically deformed, so that the side wall 112b and the contact surface 110a of the pressing pad 110 are added. Pressure contact.
At this time, since the side wall 112b is formed as described above, as shown in FIG. 4B, the portion 110b of the pressing pad 110 in the vicinity of the upper wall 112c of the block 110 is formed between the heating roll 70 and the block 110. It is not pinched by the upper wall 112c.

5 and 6 show details of the block 112. FIG.
6A is a cross-sectional view of the block 112 viewed in the direction indicated by arrow A in FIG. 5, and FIG. 6B is a cross-sectional view of the block 112 viewed in the direction indicated by arrow B in FIG. is there.
As shown in FIGS. 5 and 6, the side wall 112 b is formed in a curved shape, and has a shape in which the vicinity of the center swells toward the pressing pad 110 rather than the end.

A virtual surface passing through the edge 112d on the heating roll 70 side of the side wall 112b and perpendicular to the contact surface 110a of the pressing pad 110 is defined as P, and a virtual space surrounded by the virtual surface P, the contact surface 110a of the pressing pad 110, and the side wall 112b is defined. Assume.
At this time, regarding the cross-sectional area when this virtual space is cut by a plane perpendicular to the rotation axis of the heating roll 70, the cross-sectional area S1 (shown in FIG. 6A) near the end of the block 112 and the center of the block 112 When the cross-sectional area S2 in the vicinity (shown in FIG. 6B) is compared, the side wall 112b is formed such that S1 is larger than S2.
For example, the distance between the contact surface 110a of the pressing pad 110 and the side wall 112b at the same height is increased from the vicinity of the center toward the end.

Since both ends of the block 112 bend toward the heating roll 70, if the shape of the side wall 112b is the same between the vicinity of the center and the end portion, the internal pressure of the pressing pad 110 during pressing increases as the end portion is approached. In the vicinity, the portion 110 (shown in FIG. 4) of the pressing pad 110 protrudes between the upper wall 112 c and the heating roll 70.
On the other hand, in this embodiment, since the side wall 112b is formed as shown in FIGS. 5 to 6, the portion 110 (shown in FIG. 4) of the pressing pad 110 is the upper wall even in the vicinity of the end portion when pressed. It does not protrude between 112 c and the heating roll 70.

Next, a second embodiment will be described.
7 to 10 show a pressing pad 120 and a block 122 according to the second embodiment.
The block 122 has a recess as in the block 112, and the pressing pad 120 is bonded to the bonding surface 122 a that is the bottom of the recess of the block 122.
Further, like the block 112, the block 122 has a side wall 122b on the downstream side in the belt member traveling direction. However, unlike the side wall 112b, the block 122 does not need to have an oblique shape.

An inclined portion 120a is provided on the downstream side of the pressing pad 120 in the belt member traveling direction so that the height from the adhesive surface 112a decreases as the side wall 122b is approached.
In the state before pressing, as shown in FIG. 7A, the maximum height H1 from the bonding surface 122a of the pressing pad 120 is formed higher than the height H2 from the bonding surface 122a of the side wall 122b. However, the height H3 from the bonding surface 122a of the surface 120b on the side wall 122b side of the pressing pad 120 is formed to be lower (or the same as H2) than the height H2 from the bonding surface 122a of the side wall 122b. Yes.
On the other hand, at the time of pressing, as shown in FIG. 7B, the height H4 of the surface 120b of the pressing pad 120 is higher than the height H2 of the side wall 122b. Similarly to the example, a part of the pressing pad 120 is not sandwiched between the upper wall 122 c of the block 122 on the heating roll 70 side and the heating roll 70.

8 and 9 show details of the pressing pad 120. FIG.
9A is a cross-sectional view of the pressing pad 120 viewed in the direction indicated by arrow A in FIG. 8, and FIG. 9B is a cross-sectional view of the pressing pad 120 viewed in the direction indicated by arrow B in FIG. FIG.
As shown in FIGS. 8 and 9, the inclined portion 120 a of the pressing pad 120 is formed in a curved surface shape, and has a shape in which the vicinity of the center swells more than the end portion.

In addition, before pressing, the pressing pad 120 has a height H5 (shown in FIG. 9A) of the surface 120b near the end from the bonding surface 122a, and a height H5 from the bonding surface 122a of the surface 120b near the center. It is formed to be lower than the height H6 (shown in FIG. 9B).
In other words, before pressing, the difference (H2−H5) between the height H2 of the side wall 122b of the block 122 and the height H5 of the surface 120b near the end of the pressing pad 120 is equal to the height H2 of the side wall 122b. It is larger than the difference (H2−H6) from the height H6 of the surface 120b near the center of the pad 120.
That is, the difference between the height of the side wall 122b of the block 122 and the height of the surface 120b on the downstream side in the belt running direction of the pressing pad 120 increases as it approaches the end from the center.

As described above, since both ends of the block 122 bend toward the heating roll 70, if the shape of the pressing pad 120 is the same at the center and at the end, the internal pressure of the pressing pad 120 at the time of pressing approaches the end. In the vicinity of the end portion, a part of the pressing pad 120 protrudes between the upper wall 122c of the block 122 and the heating roll 70.
On the other hand, in this embodiment, since the pressing pad 120 is formed as shown in FIGS. 8 to 9, a part of the pressing pad 120 is connected to the upper wall 122 c of the block 122 even in the vicinity of the end during pressing. It does not protrude between the heating rolls 70.

As described above, the pressure distribution when the pressing pad 120 is pressed should be stronger on the downstream side in the belt member traveling direction. However, if the inclination of the inclined portion 120a is large, the pressure distribution in the belt member traveling direction is better. There is a possibility that the pressure will not increase on the downstream side.
Therefore, as shown in FIG. 10, the inclined portion 120a is formed by a plurality of surfaces 120c and 120d instead of a single surface, whereby the pressure distribution when the pressing pad 120 is pressed can be reduced downstream in the belt member traveling direction. Can be stronger on the side.

FIG. 11 shows a conventional pressing pad 200 and a block 202.
The block 202 has a concave portion similar to the block 112 and the block 122, and the pressing pad 200 is bonded to the bonding surface 202a which is the bottom of the concave portion of the block 202.
Further, like the block 120, the block 202 has a side wall 202b on the downstream side in the belt member traveling direction. Unlike the side wall 112b, the side wall 202b is not inclined.
Furthermore, the inclined portion as shown in FIGS. 7 to 10 is not provided on the downstream side of the pressing pad 200 in the belt traveling direction.

When the state before pressing shown in FIG. 11 (A) is changed to the state shown in FIG. 11 (B), the side wall 202b and the pressing pad 200 are in pressure contact with each other due to the elastic deformation of the pressing pad 200. To do.
At this time, as shown in FIG. 11C, a portion 200c of the pressing pad 200 in the vicinity of the upper wall 202c of the side wall 202b on the heating roll 70 side is formed between the heating roll 70 and the upper wall 202c via the belt member 72. Get caught in between.
Thus, when a part of the pressing pad 200 is sandwiched, the pressure at the sandwiched portion becomes extremely higher than other portions, and the nip width is narrowed, so that the toner fixing property is deteriorated.
Further, when the pressure at the portion where the pressing pad 200 is sandwiched becomes extremely high, the resistance force against the rotation of the belt member 72 is increased, thereby causing uneven rotation or the like, and image quality problems such as banding occur.
Furthermore, the problem that the location where the pressing pad 200 is sandwiched breaks.

  On the other hand, in this embodiment, since the pressing pad and the block are formed as shown in FIGS. 3 to 10, it is possible to prevent a part of the pressing pad from being sandwiched between the side wall of the block and the heating roll. Therefore, the problem that occurs in the example shown in FIG. 11 can be solved.

1 is a side view showing an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device according to an embodiment of the present invention. It is a figure which shows the state before the press of the press pad and block which concerns on embodiment of this invention. It is a figure which shows the state at the time of the press of the press pad and block which concern on embodiment of this invention. It is a perspective view which shows the detail of the block which concerns on embodiment of this invention. It is sectional drawing which shows the detail of the block which concerns on embodiment of this invention. It is a figure which shows the press pad and block which concern on the 2nd Embodiment of this invention. It is a perspective view which shows the detail of the press pad which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the detail of the press pad which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example in which the inclination part of the press pad which concerns on the 2nd Embodiment of this invention was formed in the several surface. It is a figure which shows the conventional press pad and block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 36 Fixing apparatus 70 Heating roll 72 Belt member 74 Guide member 76 Press unit 78 Impregnation pad 110 Press pad 112 Block 114 Housing 116 Frame 120 Press pad 122 Block 200 Press pad 202 Block

Claims (13)

A rotatable heating roll;
A belt member that travels following the rotation of the heating roll;
A pressing member that is disposed inside the belt member and presses the heating roll via the belt member;
And a support member that supports the pressing member so as to press the heating roll side.
The support member has a side wall for regulating the pressing member on the downstream side in the belt member traveling direction from the pressing member,
The pressing member does not contact the side wall in a free shape, and elastically deforms and contacts the side wall when pressing the heating roll. The fixing device according to claim 1, wherein the pressing member has a portion higher than a height of the side wall when in a free shape. The fixing device according to claim 1, wherein the pressing member presses the heating roll at a portion on a downstream side in a belt traveling direction. 4. The fixing according to claim 1, wherein when the pressing member is in a free shape, a distance between the side wall and a downstream surface of the pressing member in a belt member traveling direction becomes longer as the heating roll is approached. apparatus. The fixing device according to claim 4, wherein the side wall is formed obliquely with respect to a downstream side surface in the belt member traveling direction when the pressing member is in a free shape. The side wall includes a virtual surface that passes through an edge on the heating roll side of the side wall and is perpendicular to a downstream surface of the pressing member in a belt member traveling direction, and a belt member of the pressing member when the pressing member is in a free shape. A cross-sectional area obtained by cutting a space surrounded by a surface on the downstream side in the traveling direction and the side wall with a surface perpendicular to the rotation axis of the heating roll is formed so as to increase as it approaches the end of the support member. The fixing device according to claim 4 or 5. A rotatable heating roll;
A belt member that travels following the rotation of the heating roll;
A pressing member that is disposed inside the belt member and presses the heating roll via the belt member;
And a support member that supports the pressing member so as to press the heating roll side.
The support member has a side wall for regulating the pressing member on the downstream side in the belt member traveling direction from the pressing member,
A fixing device is provided on the downstream side of the pressing member in the belt member traveling direction so as to decrease in height as it approaches the side wall. The fixing device according to claim 7, wherein the pressing member has a portion higher than a height of the side wall when in a free shape. The fixing device according to claim 7, wherein the pressing member presses the heating roll at a portion on a downstream side in a belt traveling direction. When the free shape of the pressing member, the height of the downstream surface of the pressing member in the belt member traveling direction is equal to or less than the height of the side wall,
10. The fixing device according to claim 7, wherein when the pressing member presses the heating roll, a height of a side surface of the pressing member on a downstream side in a running direction of the belt member is higher than a height of the side wall. . The pressing member is formed such that, when in a free form, the difference between the height of the downstream surface of the pressing member in the belt member traveling direction and the height of the side wall increases as the end of the pressing member is approached. The fixing device according to claim 7. The fixing device according to claim 7, wherein the inclined portion is formed by a plurality of surfaces.   An image forming apparatus comprising the fixing device according to claim 1.

Images