JP2010224256A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing positional deviation of a belt holding unit caused by pressing force received from a pressing body. <P>SOLUTION: The image forming apparatus includes: an intermediate transfer belt unit 30 having a plurality of rotating bodies such as a backup roll 310 and an intermediate transfer belt 31 circularly moving by rotation of the plurality of rotating bodies, and detachably attached to a housing; a first rail member 100A bearing the intermediate transfer belt unit 30 from below in a gravity direction and guiding an attaching/detaching direction of the intermediate transfer belt unit 30; a secondary transfer roll 141 making pressing force F act upward in the gravity direction on the backup roll 310 provided along a conveyance path 17 of paper P; a receiving surface 101a provided in the housing and opposed in a direction where the pressing force F acts; and an opposed surface 330a provided in the intermediate transfer belt unit 30 and opposed to the receiving surface 101a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  Conventionally, there is known a transfer belt unit that is detachable from an apparatus main body of an image forming apparatus and transfers an image on a photosensitive member to a recording material (for example, see Patent Document 1).

  The transfer belt unit includes a frame that rotatably supports at least two support rollers, and a belt stretched around the support roller. The frame is used for positioning the transfer belt unit with respect to the apparatus body. A positioning part is provided.

JP 2005-189664 A

  An object of the present invention is to provide an image forming apparatus capable of reducing the positional deviation of the belt holding unit due to the pressing force received from the pressing body.

  In order to achieve the above object, one embodiment of the present invention provides the following image forming apparatus.

[1] A belt holding device that includes a plurality of rotating bodies and a belt member that circulates and moves by the rotation of the plurality of rotating bodies, and is detachably attached to a housing; And a guide member that guides the attaching / detaching direction of the belt holding device, and a pressing force that is applied upward or obliquely upward in the direction of gravity to one of the plurality of rotating bodies provided along a recording material conveyance path. An image forming apparatus comprising: a pressing body that acts on the housing; and a receiving surface that is provided on the housing and receives the pressing force via the belt holding device.

[2] The image forming apparatus according to [1], wherein the belt holding device has a facing surface that faces the receiving surface, and the facing surface is continuously formed in a direction in which the belt holding device is attached or detached. apparatus.

[3] The housing includes a first door that opens and closes in the attaching / detaching direction, and a second door that opens and closes in a direction intersecting the attaching / detaching direction, and the belt holding device includes the first door The door is attached to the housing by opening the door, and the pressing body is provided inside the second door, and the second door is closed to press the one rotating body. The image forming apparatus described.

  According to the invention which concerns on Claim 1, the position shift of the belt holding unit by the pressing force received from a pressing body can be reduced.

  According to the second aspect of the present invention, the facing surface can be used as a reference for alignment when the belt holding unit is mounted on the housing, and the facing surface can function as a guide member.

  According to the invention of claim 3, the first door can be freely opened and closed independently of the second door.

FIG. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing the intermediate transfer belt unit. FIG. 3 is a perspective view showing a housing of the image forming apparatus. 4A is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4B is an enlarged cross-sectional view showing a concave member and a protrusion of the belt cover. FIG. 5 is an enlarged cross-sectional view showing the intermediate transfer belt unit when the front cover and the side cover are closed. FIG. 6 is an enlarged cross-sectional view showing the intermediate transfer belt unit when the front cover is opened.

  FIG. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is, for example, a digital color printer, and includes a control unit (not shown) that performs image processing on image data transmitted from a host device such as a personal computer. The image forming apparatus 1 converts the image data of each color of yellow (Y), magenta (M), cyan (C), and black (K) by the image processing, and then converts the toner image based on the image data of each color. It is configured to form on paper P.

  The image forming apparatus 1 may be a copier, a facsimile machine, or a multi-function machine having a plurality of functions such as a copier, a printer, a scanner, and a facsimile machine. Further, the image forming apparatus 1 may be connected to a host device via a network such as a local area network (LAN), or may be connected according to an interface standard such as USB or RS232C.

  The image forming apparatus 1 includes a housing 10 having a substantially box-like appearance, and is installed on a floor, a stand, or the like via a grounding surface 10 a that is a lower surface of the housing 10. A front plate 11 is disposed on the front surface of the housing 10, and a front cover 12 as a first door is attached to the front plate 11 via a hinge portion 120 so as to be opened and closed. A side plate 13 is disposed on one side surface of the housing 10, and a side cover 14 as a second door is attached to the side plate 13 via a hinge portion 140 so as to be opened and closed.

  In the image forming apparatus 1, a paper feeding device 15 that accommodates the paper P is detachably disposed at the lower part of the housing 10, and the paper P after the toner image is transferred to the upper part of the housing 10. A paper discharge portion 16 to be discharged is disposed, and a paper conveyance path 17 is formed near the side cover 14 in the housing 10 so as to reach the paper discharge portion 16 from the paper supply device 15.

  Further, the image forming apparatus 1 is disposed below the intermediate transfer belt unit 30 as an intermediate transfer belt unit 30 as a belt holding device that is detachably disposed at the center of the housing 10. Under the image forming units 21Y, 21M, 21C, and 21K, and the image forming units 21Y, 21M, 21C, and 21K having the photoreceptors 22 on which the toner images for each color of YMCK are formed while rotating in the direction of the arrow in the figure. And an exposure unit 26 that irradiates the surface of the photosensitive member 22 with laser light, and toner cartridges 40Y, 40M, 40C, and 40K that are disposed above the intermediate transfer belt unit 30.

(Casing)
The housing 10 includes first and second rail members 100A and 100B serving as guide members, and a concave member 101 that prevents the intermediate transfer belt unit 30 from floating upward. The first and second rail members 100A and 100B and the concave member 101 may be formed by injection molding from, for example, a PET (polyethylene terephthalate) -based or PC (polycarbonate) -based resin, aluminum, You may form from metals, such as stainless steel.

  The first and second rail members 100A, 100B have a function of receiving the intermediate transfer belt unit 30 from below in the direction of gravity and guiding the attaching / detaching direction of the intermediate transfer belt unit 30, that is, the front-rear direction of the housing 10. .

  The front plate 11 has a first opening 110 </ b> A corresponding to the front cover 12, and a plurality of second openings 110 </ b> B above the first opening 110 </ b> A. The first opening 110A is used when the intermediate transfer belt unit 30 and the image forming units 21Y, 21M, 21C, and 21K are attached to and detached from the housing 10. The second opening 110B is used when the toner cartridges 40Y, 40M, 40C, and 40K are attached to and detached from the housing 10.

(Paper transport path)
On the paper transport path 17, a pick-up roll 17 a that takes the paper P from the paper feeding device 15 into the paper transport path 17 one by one, and a force in the direction opposite to the transport direction on the back surface of the paper so as not to double-feed the taken paper. Are provided, a correction roll 17c for correcting the skew of the paper P, and a fixing device 18 for fixing the toner image on the paper P by heating and pressurization.

(Intermediate transfer belt unit)
The intermediate transfer belt unit 30 includes first and second support portions 300A and 300B supported by the first and second rail members 100A and 100B, respectively, and a convex portion 301 having a shape corresponding to the concave member 101. Prepare. Details of the intermediate transfer belt unit 30 will be described later.

(Image forming unit)
The image forming units 21Y, 21M, 21C, and 21K are detachably disposed in the housing 10 with a certain interval in a direction inclined with respect to the ground plane 10a. The image forming units 21Y, 21M, 21C, and 21K are similarly configured, and the image forming units 21Y, 21M, 21C, and 21K uniformly charge the surface of the photosensitive member 22 and the photosensitive member 22. A charger 23, a developer 24 that forms a toner image on the surface of the photoconductor 22 by developing the electrostatic latent image formed by the exposure device 26 on the surface of the photoconductor 22 with the charged toner, and the photoconductor 22. And a photosensitive member cleaning unit 25 for collecting the toner remaining on the surface.

  The developing device 24 includes a storage portion 24a that stores toner. A developing roll 24b that supplies toner to the photosensitive member 22 and develops the electrostatic latent image on the photosensitive member 22 with the toner in the storage portion 24a. And a supply auger 24c for supplying toner to the developing roll 24b, and a stirring auger 24d for stirring the toner and supplying the toner to the supply auger 24c.

  The photoconductor cleaning unit 25 includes a storage unit 25a that stores waste toner collected from the photoconductor 22, and rotates in the storage unit 25a with a blade 25b that contacts the surface of the photoconductor 22 and scrapes off the waste toner. And a discharge auger 25c that transports waste toner that has been scraped off by the blade 25b and accumulated in the storage unit 25a to the rear side of the image forming apparatus 1 by being rotated.

(Exposure device)
The exposure device 26 includes four semiconductor lasers that emit laser light modulated with image data of each color of YMCK, a polygon mirror that branches the laser light emitted from each semiconductor laser, and laser light that is branched by the polygon mirror. A plurality of mirrors that reflect and irradiate the photoreceptor 22 to form an electrostatic latent image on the surface of the photoreceptor 22 (all not shown) are provided. The exposure device 26 is hermetically sealed with a frame so as not to be stained with toner or the like.

(Toner cartridge)
The toner cartridges 40Y, 40M, 40C, and 40K are detachably disposed in the housing 10 with a fixed interval, and are configured to supply toner of each color to the storage portion 24a of the developing device 24.

(Detailed configuration of intermediate transfer belt unit)
FIG. 2 is a perspective view showing the intermediate transfer belt unit. The intermediate transfer belt unit 30 includes the first and second support portions 300A and 300B and the convex portion 301, the intermediate transfer belt 31 as a belt member, and the housing 10 along the attaching / detaching direction 30a. The belt cover 33 is disposed between the front frame 32A and the rear frame 32B and covers the upper side of the intermediate transfer belt 31. And a belt cleaning unit 34 that scrapes and collects the toner remaining on the surface of the intermediate transfer belt 31. The details of the belt cleaning unit 34 will be described later with reference to FIG.

  The intermediate transfer belt 31 is formed of resin, rubber, or the like, and has conductivity with adjusted surface resistivity so that a toner image can be transferred. The intermediate transfer belt 31 is stretched around a plurality of rotating bodies including a backup roll 310 provided in the intermediate transfer belt unit 30 so as to be circulated. The intermediate transfer belt 31 is in contact with the primary transfer portion that contacts the photoreceptor 22 of the image forming units 21Y, 21M, 21C, and 21K, and the paper P that is transported along the paper transport path 17, and the intermediate transfer belt 31. The secondary transfer portion for transferring the upper toner image is exposed.

  The backup roll 310 is provided along the paper transport path 17 for the paper P. Other rotating bodies will be described later with reference to FIG.

  The first and second support portions 300A and 300B are arranged over the entire width of the intermediate transfer belt unit 30 in the attaching / detaching direction 30a. The first and second support portions 300A and 300B may be provided with wheels or the like so as to easily move on the rail.

  The protrusion 301 is continuously formed as protrusions 320A, 320B, 330 on the upper surface of the front frame 32A, the rear frame 32B, and the belt cover 33, and these protrusions 320A, 320B, 330 are integrally formed. It is arranged over the entire width in the attachment / detachment direction.

  The front frame 32A has a protrusion 320A constituting a part of the convex portion 301 and a positioning pin 321A for positioning the intermediate transfer belt unit 30 at a predetermined position when the intermediate transfer belt unit 30 is attached to the housing 10 and closed by the front cover 12. A backup roll support member 322 that supports the rotating shaft of the backup roll 310, and a handle 323 that is used when the intermediate transfer belt unit 30 is attached to and detached from the housing 10.

  The rear frame 32 </ b> B includes a protrusion 320 </ b> B and positioning pins 321 </ b> B similar to the front frame 32 </ b> A, and a coupling 324 provided on the rotation shaft of the backup roll 310. The coupling 324 is connected to a drive source (described later) provided in the housing 10, thereby transmitting the rotational force from the drive source to the backup roll 310.

  The belt cover 33 includes a protrusion 330 that constitutes a part of the convex portion 301 and a pair of handles 331 that are used when the intermediate transfer belt unit 30 is carried.

  The front frame 32A, the rear frame 32B, and the belt cover 33 may be formed by injection molding from, for example, a PET (polyethylene terephthalate) -based or PC (polycarbonate) -based resin, aluminum, You may form from metals, such as stainless steel. Further, the front frame 32A, the rear frame 32B, and the belt cover 33 may be integrally formed with protrusions 320A, 320B, 330, or the protrusions 320A, 320B, 330 may be manufactured as separate members. The manufactured member may be fixed to the upper surfaces of the front frame 32A, the rear frame 32B, and the belt cover 33.

(Detailed housing structure)
FIG. 3 is a perspective view showing a housing of the image forming apparatus. Note that FIG. 3 illustrates a state in which an exterior product that covers the casing 10 of the image forming apparatus 1 is removed.

  A rear plate 19 is disposed on the rear surface of the housing 10 so as to face the front plate 11. A space is formed between the front plate 11 and the rear plate 19, and the intermediate transfer belt unit 30, the image forming units 21Y, 21M, 21C, and 21K, the toner cartridges 40Y, 40M, 40C, and 40K, etc. are formed in the space. Is placed.

  On the back side of the front cover 12, a positioning hole 121 into which the positioning pin 321A of the intermediate transfer belt unit 30 is inserted, and one of the rotation shafts of the photoreceptors 22 included in the image forming units 21Y, 21M, 21C, and 21K are supported. There are provided four shaft support portions 122Y, 122M, 122C, and 122K, and a storage portion 123 that stores the backup roll support member 322 of the intermediate transfer belt unit 30.

  On the back side of the side cover 14, a secondary transfer roll 141 as a pressing body that elastically presses the backup roll 310 with the intermediate transfer belt 31 interposed therebetween by closing the side cover 14, and the sheet conveyance path 17. A paper guide 142 for guiding the paper P is provided. In addition, as a mechanism in which the secondary transfer roll 141 elastically presses the backup roll 310, for example, both ends of the rotation shaft of the secondary transfer roll 141 are supported by an elastic member (not shown) such as a spring.

  Inside the rear plate 19, a driving source 190 connected to the coupling 324 of the intermediate transfer belt unit 30, a positioning hole 191 into which the positioning pin 321 </ b> B of the intermediate transfer belt unit 30 is inserted, and a rotating shaft of the photoreceptor 22. Are provided with four shaft support portions 192Y, 192M, 192C, and 192K.

(Internal structure of intermediate transfer belt unit)
4A is a cross-sectional view taken along the line AA in FIG. 2, and illustrates a state in which the intermediate transfer belt unit is mounted in the housing. FIG. 4B is an enlarged sectional view showing the concave member and the protrusion of the belt cover. In FIG. 4A, the photoconductor 22 and the side cover 14 are shown.

  The intermediate transfer belt 31 of the intermediate transfer belt unit 30 is disposed on the opposite side of the photoreceptor 22 of each of the image forming units 21Y, 21M, 21C, and 21K with the intermediate transfer belt 31 interposed therebetween in addition to the backup roll 310 described above. Primary transfer rolls 311Y, 311M, 311C, 311K, a driven roll 312A disposed on the opposite side of the belt cleaning unit 34 with the intermediate transfer belt 31 interposed therebetween, and a driven roll 312B disposed obliquely below the backup roll 310 The intermediate transfer belt 31 is stretched by an auxiliary roll 313A arranged upstream of the primary transfer roll 311Y in the circulating movement direction and an auxiliary roll 313B arranged downstream of the primary transfer roll 311K in the circulating movement direction. Has been.

  The primary transfer rolls 311Y, 311M, 311C, and 311K primarily transfer the toner image formed on the surface of the photoreceptor 22 to the intermediate transfer belt 31 by the developing unit 24 and the like.

  The secondary transfer roll 141 is a pressing body that applies a pressing force F obliquely upward in the gravity direction to the backup roll 310. The secondary transfer roll 141 then transfers the toner image primarily transferred to the intermediate transfer belt 31 onto the paper P when the paper P transported along the paper transport path 17 passes through the backup roll 310. Next transfer.

  The belt cleaning unit 34 includes a housing 34a that stores waste toner collected from the intermediate transfer belt unit 30, and a blade 34b that contacts the surface of the intermediate transfer belt 31 and scrapes the waste toner in the housing 34a. A discharge auger 34c that is rotatably provided in the housing 34a and conveys waste toner that has been scraped off by the blade 34b and accumulated in the housing 34a.

  As shown in FIG. 4B, the concave member 101 has a receiving surface 101a facing in the pressing direction in which the pressing force F acts, and a lower surface 101b disposed substantially parallel to the grounding surface 10a.

  The protrusion 330 has a facing surface 330a that faces the receiving surface 101a, and an upper surface 330b that is disposed substantially parallel to the ground surface 10a and faces the lower surface 101b. Note that the protrusions 320A and 320B of the front frame 32A and the rear frame 32B also have the same facing surface and upper surface as the protrusion 330 of the belt cover 33.

  When the intermediate transfer belt unit 30 is moved in the pressing direction by the pressing force F from the secondary transfer roll 141, the opposing surface 330a comes into contact with the receiving surface 101a, so that the reaction force is opposite to the pressing direction. Occurs. Further, when the intermediate transfer belt unit 30 is partially inserted when the intermediate transfer belt unit 30 is attached to or detached from the housing 10, the intermediate transfer belt unit 30 is lowered by its own weight so that the front portion is lowered and the rear portion is raised. When tilted, the upper surface 330b comes into contact with the lower surface 101b, and a reaction force is generated in the direction opposite to the tilt direction.

(Operation of image forming apparatus)
Next, the operation of the image forming apparatus 1 will be described with reference to FIGS. Here, a case where the operator attaches the intermediate transfer belt unit 30 and the image forming units 21Y, 21M, 21C, and 21K to the casing 10 of the image forming apparatus 1 will be described.

(1) Mounting operation of intermediate transfer belt unit and image forming unit First, the operator opens the front cover 12 and the side cover 14 of the image forming apparatus 1. Next, the operator grasps the handle 331 of the intermediate transfer belt unit 30 to lift the intermediate transfer belt unit 30 and visually recognize the position of the convex portion 301 from above, while the convex portion 301 is the concave member 101 of the housing 10. The position is adjusted so as to fit into the housing 10 and is inserted into the housing 10 through the first opening 110A.

  The intermediate transfer belt unit 30 inserted into the housing 10 is in a state where the first and second support portions 300A and 300B are partially placed on the first and second rail members 100A and 100B. Become. At this time, even if the intermediate transfer belt unit 30 is inclined so that the front side portion is lowered due to its own weight, the angle at which the intermediate transfer belt unit 30 is inclined due to the upper surface 330b of the convex portion 301 contacting the lower surface 101b of the concave member 101 is increased. Reduced.

  Next, when the operator pushes the intermediate transfer belt unit 30 to the rear side by the handle 323, the intermediate transfer belt unit 30 is guided by the first and second rail members 100A and 100B and the convex portion 301 is provided. It is guided by the concave member 101 fitted to the housing 10 and moves to the rear side of the housing 10.

  Next, when the intermediate transfer belt unit 30 moves on the first and second rail members 100A and 100B and the rear frame 32B reaches the rear plate 19, positioning pins 321B provided on the rear frame 32B are While being inserted into the positioning hole 191 of the rear plate 19, the coupling 324 provided in the rear frame 32 </ b> B is coupled to the drive source 190 of the rear plate 19.

  Subsequently, when the operator sequentially inserts the image forming units 21Y, 21M, 21C, and 21K into the lower side of the intermediate transfer belt unit 30, the rotation shaft on the rear side of the photoconductor 22 moves to the shaft support portion 192Y of the rear plate 19. , 192M, 192C, 192K.

  Next, when the operator closes the front cover 12, positioning pins 321A provided on the front frame 32A of the intermediate transfer belt unit 30 are inserted into the positioning holes 121 of the front cover 12 and provided on the front frame 32A. The backup roll support member 322 is accommodated in the accommodating portion 123 of the front cover 12. As a result, the intermediate transfer belt unit 30 is disposed between the front cover 12 and the rear plate 19 and is attached to the housing 10.

  Further, the image forming units 21Y, 21M, 21C, and 21K are configured so that the front rotation shaft of the photosensitive member 22 is supported by the shaft support portions 122Y, 122M, 122C, and 122K of the front cover 12, thereby It is arranged between the rear plate 19 and is attached to the housing 10.

  Next, when the operator closes the side cover 14, the secondary transfer roll 141 provided on the side cover 14 comes into contact with the backup roll 310 of the intermediate transfer belt unit 30, and the backup roll 310 is tilted upward in the gravity direction. Press to.

  FIG. 5 is an enlarged cross-sectional view showing the intermediate transfer belt unit when the front cover and the side cover are closed. The intermediate transfer belt unit 30 is supported by the front cover 12 and the rear plate 19 when the front cover 12 is closed. Then, when the side cover 14 is closed, the secondary transfer roll 141 applies a pressing force F to the backup roll 310 obliquely upward in the direction of gravity, and the sheet between the intermediate transfer belt 31 and the secondary transfer roll 141 is paper. When P passes, the toner image on the intermediate transfer belt 31 is transferred to the paper P.

(2) Image formation on paper When the image forming apparatus 1 in which the front cover 12 and the side cover 14 are closed receives image data from the host apparatus, it performs image formation based on the image data. That is, after rotating the photoconductor 22 of each of the image forming units 21Y, 21M, 21C, and 21K and charging the photoconductor 22 with the charger 23, the exposure device 26 irradiates each color laser beam based on the image data, An electrostatic latent image is formed on the surface of the photoconductor 22, and the electrostatic latent image on each photoconductor 22 is developed into a toner image by the developing device 24 of each corresponding color.

  Next, the toner image on the photosensitive member 22 is primary-transferred sequentially by the primary transfer rolls 311Y, 311M, 311C, and 311K onto the surface of the intermediate transfer belt 31 circulated and moved by the drive source 190 via the coupling 324.

  In parallel with the above-described image forming operation, the sheet P is conveyed from the sheet feeding device 15 one by one by the pickup roll 17a and the retard roll 17b, and the skew is corrected by the correction roll 17c. Thereafter, when the sheet P is conveyed to the position where the secondary transfer roll 141 is arranged in accordance with the circulation movement of the intermediate transfer belt 31, the toner image on the intermediate transfer belt 31 is transferred to the sheet P by the secondary transfer roll 141. Secondary transferred. The sheet P on which the toner image is secondarily transferred is heated and pressed by the fixing unit 18 to fix the toner image, and is discharged to the sheet discharge unit 16.

(3) Front cover opening / closing operation When the operator opens the front cover 12 to perform, for example, replacement work of the image forming units 21Y, 21M, 21C, and 21K, paper jam recovery work, and the like, the front frame 32A is positioned. The pin 321A comes off. At this time, since the side cover 14 remains closed, the intermediate transfer belt unit 30 is in a state where only the rear side is supported by the rear plate 19. Since the intermediate transfer belt unit 30 receives the pressing force F from the secondary transfer roll 141 in this state, the intermediate transfer belt unit 30 moves in the direction in which the pressing force F acts.

  FIG. 6 is an enlarged cross-sectional view showing the intermediate transfer belt unit when the front cover is opened. The intermediate transfer belt unit 30 is moved in the acting direction by the pressing force F from the secondary transfer roll 141, and the receiving surface 101 a of the concave member 101 arranged to face the acting direction is provided on the convex portion 301. By receiving the facing surface 330a, the movement of the intermediate transfer belt unit 30 in the acting direction is suppressed to a distance L shown in FIG. This distance L is such that when the front cover 12 is closed again, the positioning pin 321A is inserted into the positioning hole 121 without opening the side cover 14.

  When the operator completes the desired work and closes the front cover 12, the positioning pin 321A of the intermediate transfer belt unit 30 is inserted into the positioning hole 121 and attached to the housing 10. For the image forming units 21Y, 21M, 21C, and 21K, the rotation shaft of the photosensitive member 22 is supported by the shaft support portions 122Y, 122M, 122C, and 122K and attached to the housing 10, and the image forming apparatus 1 is The state returns to the state where the above-described image forming operation is possible.

[Other embodiments]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, as shown in FIG. 4B, the receiving surface and the facing surface are provided so as to be in surface contact, but at least one of the receiving surface and the facing surface is changed, Line contact or point contact may be performed.

  In the above embodiment, the receiving surface and the opposing surface are provided in a straight line. However, the receiving surface and the opposing surface may be provided in a curved shape as long as they face each other in the direction in which the pressing force F acts. I can't.

  Further, in the above embodiment, the convex portion including the opposing surface is continuously provided on the upper surface of the intermediate transfer belt unit. Further, a plurality of convex portions including the opposing surface may be provided on the upper surface of the intermediate transfer belt unit.

  Further, in the above embodiment, the pressing direction in which the pressing force F acts is obliquely above the gravitational direction, but may be upward as compared with the horizontal direction. For example, the pressing direction may be above the gravitational direction.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Housing, 10a ... Ground plane, 11 ... Front plate, 12 ... Front cover, 13 ... Side plate, 14 ... Side cover, 15 ... Paper feeder, 16 ... Paper discharge part, 17 ... Paper transport path, 17a ... pickup roll, 17b ... retard roll, 17c ... correction roll, 18 ... fixer, 19 ... rear plate, 21Y, 21M, 21C, 21K ... image forming unit, 22 ... photoconductor, 23 ... charger 24 ... developer, 24a ... accommodating section, 24b ... developing roll, 24c ... supply auger, 24d ... stirring auger, 25 ... photoconductor cleaning section, 25a ... accommodating section, 25b ... blade, 25c ... discharge auger, 26 ... exposure 30 ... intermediate transfer belt unit, 30a ... removal direction, 31 ... intermediate transfer belt, 32A ... front frame, 32B ... rear frame, 3 ... belt cover, 34 ... belt cleaning section, 34a ... housing, 34b ... blade, 34c ... discharge auger, 40Y, 40M, 40C, 40K ... toner cartridge, 100A ... first rail member, 100B ... second rail member 101 ... concave member, 101a ... receiving surface, 101b ... lower surface, 110A ... first opening, 110B ... second opening, 120 ... hinge part, 121 ... positioning hole, 122Y, 122M, 122C, 122K ... shaft support part , 123, accommodating portion, 140, hinge portion, 141, secondary transfer roll, 142, paper guide, 190, drive source, 191, positioning hole, 192 Y, 192 M, 192 C, 192 K, shaft support portion, 300 A, first. Support section, 300B ... second support section, 301 ... convex section, 310 ... backup roll, 311Y, 3 1M, 311C, 311K ... primary transfer roll, 312A, 312B ... driven roll, 313A, 313B ... auxiliary roll, 320A ... projection, 320A, 320B ... projection, 321A, 321B ... positioning pin, 322 ... backup roll support member, 323 ... handle, 324 ... coupling, 330 ... projection, 330a ... opposite surface, 330b ... upper surface, 331 ... handle

Claims (3)

A belt holding device that has a plurality of rotating bodies and a belt member that circulates and moves by rotation of the plurality of rotating bodies, and is detachably attached to the housing;
A guide member that receives the belt holding device from below in the direction of gravity and guides the attaching / detaching direction of the belt holding device;
A pressing body that applies a pressing force upward or obliquely upward in the direction of gravity to one rotating body provided along the recording material conveyance path among the plurality of rotating bodies;
An image forming apparatus comprising: a receiving surface that is provided in the housing and receives the pressing force via the belt holding device. The belt holding device has a facing surface facing the receiving surface,
The image forming apparatus according to claim 1, wherein the facing surface is continuously formed in an attaching / detaching direction of the belt holding device. The housing includes a first door that is opened and closed in the attaching / detaching direction, and a second door that is opened and closed in a direction intersecting the attaching / detaching direction.
The belt holding device is attached to the housing by opening the first door,
The image forming apparatus according to claim 2, wherein the pressing body is provided inside the second door and presses the one rotating body by closing the second door.

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