JP2007293085A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus designed so as to reduce pressing force applied to an endless belt by a contact member in a direction perpendicular to the direction of conveyance of an endless belt and prevent damage to the end face of the endless belt. <P>SOLUTION: In the image forming apparatus in which the endless belt is laid across a plurality of rotation bodies in a tensioned condition to be rotated and driven, at least one end of at least one of the rotation bodies has a belt restricting member that restricts the movement of the endless belt in the direction of the shaft of this rotation body. In addition, the contact member is disposed so as to be in contact with the rotation body via the endless belt and from outside the endless belt. The contact member is disposed furthest downstream in the direction of conveyance of the endless belt in a belt internal face contact area where the internal face of the endless belt is in contact with the one rotation body. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus provided with an endless belt for conveying a recording material.

  2. Description of the Related Art In an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions, a latent image corresponding to an original is formed on a photosensitive member, and toner is applied to the latent image. Thus, the visualized toner image is transferred onto a recording material, and then the toner image transferred onto the recording material is fixed and discharged.

  Also, in an image forming apparatus for forming a color image, Y, M, C, and K latent images corresponding to the original color are formed on four photosensitive drums, and visualized four color toner images are formed. , After the primary transfer in the primary transfer area to the intermediate transfer body consisting of an endless belt, transported to the secondary transfer area, secondary transfer on the recording material, fixed by the fixing device, and discharged outside the machine There is something.

  Further, as a fixing device, a heating roller having a built-in heating means such as a halogen heater, an endless fixing belt stretched around a fixing roller, and a pressure roller that pressurizes the fixing roller via the fixing belt There is a belt-fixing type fixing device that heats and presses a recording material onto which a toner image is transferred at a nip portion formed by a fixing belt and a pressure roller. Since the heat capacity of the heat roller of the fixing belt is small, the fixing device has an advantage of shortening the warm-up time and saving energy.

  On the other hand, in an image forming apparatus provided with an endless conveyance belt such as an intermediate transfer member or a fixing belt, a belt cleaning member for removing toner or paper dust adhering to the surface of the conveyance belt or tension on the conveyance belt is applied. Some tension applying members are provided as contact members for the conveyor belt.

  However, in an image forming apparatus using an endless conveyance belt such as an intermediate transfer member or a fixing belt, the endless belt is moved in the roller axial direction due to manufacturing variations between the endless belt and a roller that stretches the endless belt. However, there is a problem that the belt member may be offset or tilted, and if the belt end surface is received by the belt regulating member against the endless belt offset force, but the belt member has a large pressing force, the belt member is There are cases where problems such as riding on the regulating member or breaking the end of the belt member occur.

  Further, in an image forming apparatus having an abutting member such as a belt cleaning member or a tension applying member, the abutting member is not supported by the conveying belt due to manufacturing variations of the abutting member or uneven pressing force on the conveying belt. There is a problem that the offset and inclination are further amplified.

  FIG. 5 is a diagram illustrating a conventional fixing device including a cleaning roller that cleans the fixing belt as a contact member of the endless belt. In the fixing device shown in FIG. 5, the fixing belt 11 is wound between the fixing roller 13 and the heating roller 12, and a detent ring (belt regulating member) 15 is disposed adjacent to the fixing roller 13 and comes into contact therewith. The configuration is such that the cleaning roller 16 as a member is disposed at an intermediate position between the fixing roller 13 and the heating roller 12, and there is no backup member on the back surface of the fixing belt 11 at the position where the cleaning roller 16 contacts. (See, for example, Patent Document 1).

  In order to improve the cleaning performance of the cleaning roller, two methods of increasing the contact load between the cleaning roller and the fixing belt or increasing the contact area between the cleaning roller and the fixing belt can be considered. The position of the cleaning roller 16 described in Patent Document 1 is disadvantageous in terms of cleaning performance as compared with these two methods. That is, in order to increase the contact load between the cleaning roller 16 and the fixing belt 11, the cleaning roller 16 is contacted with the inner surface of the belt, which is a region where the fixing belt 11 contacts the heating roller 12 in the heating roller 12 (or the fixing roller 13). The contact area (hereinafter, the area where the inner surface of the endless belt is in contact with the surface of the wound roller is referred to as the belt inner surface contact area) should be brought into contact with the fixing belt 11 within Rn, and the heating roller 12 (or fixing roller) behind 13), the cleaning roller 16 can be pressed against the fixing belt 11 with a required force, but this is not possible at the position of the cleaning roller 16 shown in FIG. Further, the position of the cleaning roller 16 in FIG. 5 is a position where the contact area between the cleaning roller 16 and the fixing belt 11 cannot be increased.

  In addition to the cleaning roller, the contact member to the fixing belt includes an external heating roller that presses and heats the outer side of the fixing belt and a tension roller that increases the tension of the fixing belt. In order to increase the tension of the cleaning roller, the contact load between the external heating roller or the tension roller and the fixing belt is increased by arranging a back-up member on the back surface of the fixing belt as well as improving the cleaning performance of the cleaning roller. A method of increasing the contact area between the external heating roller or tension roller and the fixing belt is conceivable.

  FIG. 6 is a conventional example of a fixing device provided with a tension roller that also serves as an oil application to a fixing belt. The endless belt (fixing belt) 31 is wound between the fixing roller 32 and the heating roller 33, and a stopper flange (belt regulating member) 35 is disposed adjacent to the heating roller 33 to prevent the fixing belt 31 from being displaced. ing. In order to increase the contact area between the oil application roller (tension roller) 36 that is a contact member to the fixing belt 31 and the fixing belt 31, the belt inner surface contact region Rn of the fixing belt 31 in the heating roller 33 is used as the tension roller 36. 6 is preferably disposed at the most upstream position or the most downstream position in the belt conveyance direction. In the conventional example shown in FIG. 6, the tension roller 36 is disposed at the most upstream position of the belt inner surface contact region Rn of the fixing belt 31. (For example, see Patent Document 2).

  The present inventor has disclosed an image forming apparatus having a configuration in which a belt regulating member for preventing a deviation of an endless belt is disposed adjacent to a roller around which the endless belt is wound. It is understood that there is a problem that the end face of the endless belt is subjected to a repulsive stress concentrated from the belt restricting member on the end face of the endless belt at the position where the end face is first in contact with the belt restricting member. Hereinafter, this phenomenon will be described with reference to FIG.

  FIG. 7 is a developed view for explaining the state of the fixing belt 31 wound around the heating roller 33 when a biasing force is generated in the endless belt in the conventional example shown in FIG.

  In FIG. 7, the fixing belt 31 wound around the heating roller 33 and conveyed in the A direction starts to be shifted in the B direction, and the end surface of the fixing belt 31 is one surface of the belt regulating member 35 adjacent to the heating roller 33. The end surface of the fixing belt 31 protrudes from the position Pt1 where the fixing belt 31 first contacts the belt regulating member 35 by the amount of protrusion a by further conveying in the A direction and moving toward the B direction. Become.

  The position at which the fixing belt 1 is separated from the belt regulating member 35 is represented by Pt2, and the repulsive force F from the belt regulating member 35 received by the fixing belt 1 in the belt end surface contact region Rt from the position Pt1 to the position Pt2 is shown in FIG. As shown on the left, it becomes maximum at the position Pt1 where the amount of protrusion a is to be absorbed, and then decreases rapidly as the fixing belt 1 is conveyed in the A direction, and the repulsive force F is dispersed.

As described above, in an image forming apparatus configured to wind an endless belt around a roller in which a belt regulating member is disposed adjacently, the end surface of the endless belt has the maximum repulsive force at the most upstream position in the region in contact with the belt regulating member. However, in the configuration of the fixing device in Patent Document 2, the tension roller 36 is disposed close to the most upstream position Pt1 in the belt conveying direction of the belt end surface contact region Rt of the fixing belt 31 in the heating roller 33 ( 6 and FIG. 7), and is a position that receives the maximum repulsive force because the fixing belt 31 is held from the outside by the tension roller 36 that is a contact member of the heating roller 33. In addition, the tension roller 36 A new biasing force is applied to the fixing belt 31 due to variations in pressing force from side to side, further increasing the shifting force to the fixing belt 31. There is a problem in that. When a large pressing force of the fixing belt 31 toward the end portion of the heating roller 33 is generated, the end surface of the fixing belt 31 rides on one of the belt regulating members 35 provided at both ends of the heating roller 33 and is deformed. Or the end of the fixing belt 31 enters into the gap between the heating roller 33 and the belt regulating member 35, and the problem of damaging the fixing belt 31 is likely to occur.
JP 2002-169396 A JP-A-11-249464

  In order to solve the above problems, the present invention has a configuration in which an endless belt is wound around a roller provided with a belt regulating member adjacent thereto, and an abutting member is brought into contact with the roller from the outside of the endless belt. It is an object of the present invention to provide an image forming apparatus that can reduce the pressing force in a direction perpendicular to the endless belt conveyance direction generated in the endless belt with a simple configuration and prevent damage to the end face of the endless belt. To do.

  The above object is achieved by the following means.

  1. In the image forming apparatus in which an endless belt is stretched around a plurality of rotating bodies and is driven to rotate, at least one end of at least one rotating body among the plurality of rotating bodies is arranged in the axial direction of the rotating body. A belt regulating member that regulates movement of the endless belt; and a contact member that is disposed at a position that comes into contact with the one rotating body across the endless belt from the outside of the endless belt. The member is disposed at the most downstream position in the endless belt conveyance direction in a belt inner surface contact area, which is an area where an inner surface of the endless belt contacts the one rotating body. .

  2. 2. The image forming apparatus according to 1, wherein the contact member is a belt cleaning member.

  In the image forming apparatus having a configuration in which the contact member according to the present invention is configured to contact the roller that winds the endless belt from the outside of the endless belt, the position of the contact member is appropriately disposed. While increasing the contact load of the contact member and increasing the contact area between the contact member and the endless belt, the pressing force applied to the endless belt applied in a direction perpendicular to the endless belt conveyance direction can be concentrated with a simple configuration. It can be mitigated and damage to the end face of the endless belt can be prevented. Further, by reducing the pressing force on the endless belt, the endless belt can be operated smoothly and the life of the endless belt can be extended.

  FIG. 1 is a cross-sectional view for explaining the configuration of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus includes an image forming apparatus main body GH and an image reading apparatus YS. The image forming apparatus main body GH is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-like intermediate transfer member 6A, a sheet feeding and conveying unit, a fixing device 9A, and the like. Consists of.

  An image reading device YS including an automatic document feeder 201 and a document image scanning exposure device 202 is installed on the upper part of the image forming apparatus main body GH. The document d placed on the document table of the automatic document feeder 201 is transported by a transport unit, and an image on one or both sides of the document is scanned and exposed by the optical system of the document image scanning exposure device 202, and the line image sensor CCD is scanned. Is read.

  A signal formed by photoelectric conversion by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit, and then exposure means 3Y, 3M, 3C, 3K. Sent to.

  In the image forming unit 10Y that forms a yellow (Y) image, a charging unit 2Y, an exposure unit 3Y, a developing device 4Y, and a cleaning unit 8Y are arranged around the photosensitive drum 1Y. In the image forming unit 10M that forms a magenta (M) color image, a charging unit 2M, an exposure unit 3M, a developing device 4M, and a cleaning unit 8M are arranged around the photosensitive drum 1M. In the image forming unit 10C that forms a cyan (C) color image, a charging unit 2C, an exposure unit 3C, a developing device 4C, and a cleaning unit 8C are arranged around the photosensitive drum 1C. In the image forming unit 10K that forms a black (K) image, a charging unit 2K, an exposure unit 3K, a developing device 4K, and a cleaning unit 8K are arranged around the photosensitive drum 1K. The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure device 3C, and the charging unit 2K and the exposure device 3K constitute a latent image forming unit.

  The developing devices 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner having a small particle diameter and a carrier.

  The intermediate transfer member 6A is wound around rollers that are a plurality of rotating members and is driven to circulate.

  The fixing device 9 </ b> A is an endless fixing belt 91 that is stretched around two rotating bodies, that is, a heating roller 92 and a fixing roller 93, and a pressure that presses the fixing roller 93 via the fixing belt 91. The toner image on the recording material P is fixed by heating and pressing at a nip portion formed between the fixing belt 91 and the pressure roller 94.

  Thus, each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating intermediate transfer body 6A by the transfer means 7Y, 7M, 7C, and 7K (primary transfer). A toner image synthesized with a color image is formed. The recording material P accommodated in the paper feeding cassette 20 is fed by the paper feeding means 21 and is conveyed to the transfer means 7A via the paper feeding rollers 22A, 22B, 22C, 22D, the registration rollers 23, etc. A color image is transferred onto P (secondary transfer). The recording material P to which the color image has been transferred is heated and pressurized in the fixing device 9A, and the color toner image on the recording material P is fixed. Thereafter, the sheet is sandwiched between the sheet discharge rollers 24 and placed on the sheet discharge tray 25 outside the apparatus.

  On the other hand, after the color image is transferred to the recording material P by the transfer unit 7A, the residual toner is removed by the cleaning unit 8A from the intermediate transfer body 6A in which the recording material P is separated by curvature.

  Although the above is an image forming apparatus that forms a color image, the present invention can also be applied to an image forming apparatus that forms a monochrome image.

  FIG. 2 is a cross-sectional view of a fixing device including a fixing belt that is an endless belt and a cleaning member that is a contact member according to an embodiment of the present invention.

  The fixing belt 91 uses, for example, a heat-resistant resin belt made of PI (polyimide) having a thickness of 70 μm as a base, and a heat-resistant silicon rubber having a thickness of 200 μm with an outer peripheral surface of the base as an elastic layer (hardness 30 °: JIS K6253 (ISO7619) durometer type A spring type hardness tester), and a surface layer of 30 μm thick PFA (perfluoroalkoxy) tube. The outer diameter is 80 mm, for example.

  The heating roller 92 which is one of a plurality of rotating bodies incorporates a halogen lamp 92A as a heating means for heating the fixing belt 91. For example, a cylindrical hollow rotating body 922 having a thickness of 2 mm formed of aluminum or the like. The outer peripheral surface is coated with a heat-resistant PFA having a thickness of 30 μm as a surface layer 923 to constitute a hard roller. The outer diameter is 47 mm, for example.

  The fixing roller 93, which is one of a plurality of rotating bodies, is formed by, for example, covering a solid cored bar 931 formed of metal such as iron with heat-resistant silicon and sponge having a thickness of 10 mm as an elastic layer 932. Further, the surface layer 933 is covered with a PFA tube having a thickness of 30 μm and configured as a soft roller. In addition, an outer diameter dimension is 40 mm, for example.

  The pressure roller 94 incorporates a halogen lamp 94A as a heating means for heating the fixing belt 91. For example, the outer peripheral surface of a cylindrical hollow rotating body 941 having a thickness of 3 mm formed of aluminum or the like is used as an elastic layer 942. Covered with 3 mm thick heat-resistant silicone rubber (hardness 30 °: according to durometer type A spring type hardness tester specified by JIS, K6253 (ISO7619)), and further as PFA having a thickness of 30 μm as a release layer 943 It is covered with a tube and configured as a hard roller. In addition, an outer diameter dimension is 50 mm, for example.

  Further, a temperature sensor S1 that detects the temperature of the heating roller 92 via the fixing belt 91, a temperature sensor S2 that detects the temperature of the fixing roller 93 via the fixing belt 91, and a temperature sensor that detects the temperature of the pressure roller 94. S3 is provided.

  The cleaning roller 98, which is a belt cleaning member, has a thin heat-resistant resin layer 983 on a relatively thick thermally conductive base 982 such as metal. By configuring the cleaning roller 98 with a member having a relatively large heat capacity, the temperature reduction efficiency can be improved.

  The fixing belt 91 is wound between the heating roller 92 and the fixing roller 93. Here, a region from the position Pn1 to Pn2 where the fixing belt 91 is wound around the heating roller 92 is referred to as a belt inner surface contact region Rn.

  The cleaning roller 98 is disposed at a position Pn2 that is the most downstream position in the rotation direction of the belt inner surface contact region Rn, and is pressed against the fixing belt 91 at the time of cleaning by an attaching / detaching mechanism (not shown) and separated at the end of cleaning.

  In the above configuration, when the fixing roller 93 is rotated clockwise by driving means (not shown), the fixing belt 91 and the heating roller 92 are also rotated clockwise, and the pressure roller 94 is rotated counterclockwise. Further, the fixing belt 91 in contact with the heating roller 92 is heated by the halogen lamp 92A, and the pressure roller 94 is also heated by the halogen lamp 94A. Since the pressure roller 94 is urged in the direction of the fixing roller 93 by an urging means (not shown), the nip portion N between the fixing belt 91 wound around the fixing roller 93 and the pressure roller 94. Thus, the fed recording material P is heated and pressurized, and the toner image on the recording material P is fixed.

  Note that any heating means may be used as a heating means for heating the fixing belt 91. For example, an induction heating heating element using an exciting coil may be used. Further, the position of the heating means is not necessarily in the heating roller 92 or the like, and may be disposed anywhere as long as the fixing belt 91 can be heated.

  Further, as the contact member according to the present invention, a tension roller for pressing the fixing belt or an external heating roller for heating the fixing belt from the outside may be provided at the position of Pn2 instead of the belt cleaning member.

  FIG. 3 is a side sectional view for explaining the configuration and operation of the belt regulating member 95 of the fixing device, and FIG. 4 is a sectional view taken along line AA in FIG.

  In FIG. 3, the heating roller 92 includes a cored bar 921 that is press-fitted into the inner diameter of the hollow rotating body 922, and a rotating shaft 921 </ b> A is formed on the cored bar 921. The rotation shaft 921A is rotatably held in a direction perpendicular to the side plate 97 of the fixing device 9A by a bearing B2 fixed via a bearing holder BH2. The fixing roller 93 is rotatably held when a rotation shaft 931A formed on the core metal 931 is fitted to a bearing B3 fixed to the side plate 97 via a bearing holder BH3.

  The angle adjustment member 96 has one surface fixed to the surface of the side plate 97 that faces the heating roller, and the other surface that is a contact portion with the belt regulating member 95 is opposed to the side plate 97. An inclined surface is formed.

  The belt regulating member 95 includes a central hole (not denoted by reference numeral) that is rotatably fitted and held on the rotation shaft 921A, one end surface (not denoted by reference numeral) that contacts the inclined surface of the angle adjusting member 96, and the fixing belt 91. And has a regulating surface (no reference numeral) that is the other end surface that is in contact with the angle adjustment member 96 and is disposed between the angle adjusting member 96 and the heating roller 92. The fitting dimension between the center hole of the belt restricting member 95 and the rotation shaft 921A is such that one end face of the belt restricting member 95 abuts the inclined surface of the angle adjusting member 96 and the belt restricting member 95 is inclined to the angle adjusting member 96. Even when it is tilted along the surface, it is formed to a size that can rotate smoothly with the rotating shaft 921A.

  In the present embodiment, the belt regulating member 95 is inclined along the inclined surface of the angle adjusting member 96. However, the angle adjusting member 96 is not provided, and the rotating shaft 921A is not inclined without tilting the belt regulating member 95. The present invention can also be applied to a configuration that is arranged at right angles to each other.

  In FIG. 4, Pt <b> 1 indicates that the end surface of the fixing belt 91 first contacts the belt regulating member 95 in a state where the end surface of the fixing belt 91 presses the belt regulating member 95 and contacts the inclined surface of the angle adjusting member 96. Pt2 indicates the position of the contact start point for contact, and Pt2 indicates that the end surface of the fixing belt 91 presses the belt regulating member 95 to contact the inclined surface of the angle adjusting member 96, and then the end surface of the fixing belt 91 is belt-regulated. The position of the contact end point that is separated from the member 95 is shown.

  The angle of the inclined surface of the angle adjusting member 96 is such that the angle formed by the regulating surface of the belt regulating member 95 at the contact start point Pt1 and the rotation shaft 921A is the regulation surface of the belt regulating member 95 at the contact end point Pt2. The side plate 97 is fixed so as to be larger than an angle formed with the rotation shaft 921A.

  At the contact end point Pt2, the end face of the fixing belt 91 comes into contact with the restriction surface of the belt restriction member 95 due to the deviation of the fixing belt 91, and one end face of the belt restriction member 95 comes into contact with the inclined surface of the angle adjustment member 96. Immediately after this, there is still a gap between the end face of the fixing belt 91 and the regulating surface of the belt regulating member 95, and the gap between the fixing belt 91 transported from the fixing roller 93 to the heating roller 92 and the belt regulating by this gap. The contact of the member 95 with the regulating surface is performed smoothly. Thereafter, due to further deviation of the fixing belt 91, the end surface of the fixing belt 91 contacts the regulating surface of the belt regulating member 95 in the entire belt end surface abutting region between the abutting start point Pt1 and the abutting end point Pt2. Touch.

  In the present embodiment, the abutting portion that abuts the belt regulating member 95 of the angle adjusting member 96 is an inclined surface. However, the present invention is not limited to this, and a shape having a step may be formed. Different parts may be provided.

  This experiment was performed using the fixing device as described above under the following conditions.

Nip width: 16.0mm
Process speed: 300mm / sec
Set temperature (standby and paper feed)
Heating roller: 200 ° C
Pressure roller: 180 ° C
Inclination angle of belt regulating member: 1.6 °
Fusing force of fixing belt: 30N
The biasing force of the fixing belt applied by the cleaning roller: 10 N (set by changing the pressing force on the left and right of the cleaning roller)
Operating time: 10 hours continuous (however, an idling time of 5 minutes was provided every hour)
Example 1
As shown in FIG. 2, the cleaning roller 98 was disposed at the position Pn2, and the image forming apparatus was operated continuously for 10 hours. No abnormality was found.

(Comparative Example 1)
When the cleaning roller 98 is disposed at the position Pn1 and the image forming apparatus is operated continuously for 10 hours, stress concentrates on the end surface of the fixing belt 91 at the position of Pt1, and the end surface of the fixing belt 91 rides on the belt regulating member 95 or The end face of the fixing belt 91 was observed to be bent, and the image forming experiment could not be continued.

  As a result of the experiment, fixing at the position of the contact start point Pt1 is achieved by using a fixing device in which the cleaning roller, which is the contact member according to the present invention, is disposed at the most downstream position in the belt conveying direction in the belt inner surface contact region. It has been found that the concentration of the offset force of the belt 91 is dispersed and relaxed, and damage such as deformation and buckling of the end face of the fixing belt 91 can be prevented.

  Further, as in the present embodiment, in the fixing device in which the roller having the belt regulating member adjacent thereto is a heating roller and the contact member is a cleaning roller, the toner attached to the fixing belt is sufficiently heated. There is an advantage that the cleaning effect is also improved.

  In this embodiment, an example of a fixing belt has been described as an endless belt. However, the present invention can be applied to any endless belt such as an intermediate transfer member, a recording material conveyance belt, or a photosensitive belt.

1 is a cross-sectional view for explaining a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view of a fixing device including a fixing belt that is an endless belt according to an embodiment of the present invention. FIG. 4 is a side sectional view for explaining the configuration and operation of a belt regulating member of the fixing device according to the embodiment of the present invention. It is AA sectional drawing of FIG. It is a figure which shows the prior art example of the fixing device provided with the cleaning roller which cleans a fixing belt as a contact member of an endless belt. It is a conventional example of a fixing device provided with a tension roller that also serves to apply oil to a fixing belt. FIG. 7 is a development view for explaining the state of the fixing belt 31 wound around the heating roller 33 when a shift force is generated in the endless belt in the conventional example shown in FIG. 6.

Explanation of symbols

9A Fixing device 11, 31, 91 Fixing belt (endless belt)
12, 33, 92 Heating roller 13, 33, 93 Fixing roller 14, 34, 94 Pressure roller 15, 35, 95 Belt regulating member 36 Oil application roller (tension roller: contact member)
96 Angle adjustment member 16, 98 Cleaning roller (contact member)
Pn1 Most upstream position in belt inner surface contact area Pn2 Most downstream position in belt inner surface contact area Pt1 Most upstream position in belt end surface contact area Pt2 Most downstream position in belt end surface contact area Rn Belt inner surface contact area Rt Belt end surface contact Contact area

Claims (2)

In an image forming apparatus in which an endless belt is stretched around a plurality of rotating bodies and rotated.
A belt regulating member that regulates movement of the endless belt in the axial direction of the rotating body at at least one end of at least one rotating body of the plurality of rotating bodies;
An abutting member disposed at a position abutting on the one rotating body across the endless belt from the outside of the endless belt;
The contact member is disposed at a most downstream position in the endless belt conveyance direction in a belt inner surface contact region where an inner surface of the endless belt is in contact with the one rotating body. Image forming apparatus. The image forming apparatus according to claim 1, wherein the contact member is a belt cleaning member.

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