JP2006133565A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To pprevent occurrence of noise caused by minute vibrations of a cleaning blade and to improve image quality in an image forming apparatus provided with a transfer cleaner fixed to a bearing member for rotatively supporting a tension roller affording a tension to a belt body. <P>SOLUTION: The image forming apparatus comprises: a transfer belt unit consisting of the tension roller of affording a tension to a transfer belt, a cleaning means disposed on the position opposite to the tension roller and a bearing member which rotatively supports the tension roller and fixes the cleaning means; a paper feeding means; a photoreceptor drum unit; a fixing means; and a paper discharge means. In the image forming apparatus, the cleaning means is elastically supported from almost vertical direction with respect to the sliding direction of the bearing member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a recording apparatus that employs an electrophotographic system, and more particularly to a support structure of a transfer cleaner.

  In an image forming apparatus using a transfer belt, in order to stabilize the cleaning performance without being affected by belt circumference error or tension error, a cleaning blade is brought into contact with a tension roller that applies tension to the belt. In some cases, the tension roller can follow the position fluctuation. That is, since the cleaning blade is in direct or indirect contact with the tension roller, the relative position between the tension roller and the cleaning blade does not change even if the position of the tension roller changes.

  In Cited Document 1, a tension applying mechanism that urges the tension roller in the belt stretching direction, a cleaning unit at a position opposed to the tension roller, a rotational force regulating member of the cleaning unit, and a relative position between the cleaning unit and the tension roller are regulated. The configuration of a transfer belt unit including a position regulating member is described.

  Here, as shown in FIGS. 3 to 6 of the cited document 1, a long hole is formed in the belt tension direction on the frame side surface of the transfer belt unit, and a fixed shaft that supports the tension roller is passed through the long hole. The tension roller is swingably supported in the long hole.

JP 2003-149912 A

  Here, in the support structure of the cleaning means as in Patent Document 1, the tension roller fixing shaft moves in a long hole provided on the side surface of the frame of the transfer belt unit. There is an engagement backlash or a minute fit backlash between the fixed shaft and the long hole. Due to this backlash, the fine vibration of the cleaning blade during cleaning is amplified and propagated to the frame, the rotational force restricting member, the position restricting member and the like, and as a result, noise from the apparatus main body may be generated.

  Furthermore, the vibration may amplify the vibration of the cleaning blade itself, and untransferred toner to be cleaned may slip through the cleaning blade contact portion, and the slipped toner may be retransferred to reduce image quality.

  Therefore, the present invention aims to prevent noise caused by slight vibration of the cleaning blade and improve image quality in an image forming apparatus in which a transfer cleaner is fixed to a bearing member that rotatably supports a tension roller that applies tension to a belt body. Objective.

  In order to achieve the above object, the present invention provides a tension roller for applying tension to a transfer belt, a cleaning unit disposed at a position opposite to the tension roller, a rotation support for the tension roller, and fixing the cleaning unit. In an image forming apparatus comprising a transfer belt unit comprising a bearing member, a paper feed means, a photosensitive drum unit, a fixing means, and a paper discharge means, the direction of the bearing member is substantially perpendicular to the sliding direction of the bearing member. The cleaning means is elastically supported.

  According to the present invention, the lower side of the bearing member that rotatably supports the tension roller is rigidly supported, and the upper side of the bearing member is elastically supported, so that the vertical backlash of the bearing member is pressed and fixed directly to the bearing member. The vibration of the blade of the transfer cleaner can be reduced or eliminated to reduce or eliminate noise and stabilize the apparatus quality and image quality.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is an overall configuration diagram of an image forming apparatus according to the present embodiment. First, the image forming process will be described with reference to FIG.

  The image forming apparatus shown in FIG. 1 has four photosensitive drums 10a to 10d that form toner images of yellow, magenta, cyan, and black. A charger, a developing device, and a cleaner (not shown) are disposed around the photosensitive drums 10a to 10d, respectively, and are unitized as process cartridges 1a to 1d. Above these process cartridges 1a to 1d, an intermediate transfer belt 2 as an example of a belt body is disposed so as to be in contact with the respective photosensitive drums 10a to 10d.

  The photosensitive drums 10a to 10d are each charged by a charger (not shown), and the color separated yellow, magenta, cyan, and black light images are exposed by the exposure device 6, and the photosensitive drums 10a to 10d are exposed to yellow. , Magenta, cyan and black latent images are formed. Each latent image is developed by a developing device, and yellow, magenta, cyan, and black toner images are formed on the photosensitive drums 10a to 10d.

  As the photosensitive drums 10a to 10d rotate, the toner image arrives at a primary transfer portion where the photosensitive drums 10a to 10d and the intermediate transfer belt 2 come into contact with each other. The toner images are sequentially transferred to the intermediate transfer belt 2 by primary transfer rollers 2a to 2d disposed to face the respective photoconductive drums 10a to 10d. A primary transfer bias is applied to the primary transfer rollers 2a to 2d from an electrical board described later.

  The sheets P stored in the feeding cassette 4 are fed one by one by a pickup roller 8, and after the timing is adjusted by a registration roller 9, the sheet P is composed of a secondary transfer roller 3 and an intermediate transfer belt 2. The toner images on the intermediate transfer belt 2 are collectively transferred to the nip portion and secondarily transferred. Thereafter, the sheet P on which the toner image has been transferred is conveyed to the fixing device 5 where it is fixed by receiving heat and pressure, whereby the toner of each color is melted and mixed and fixed on the sheet P. After that, the sheet is discharged to the discharge tray 7 by the discharge conveying means 21 provided downstream of the fixing device 5.

  The arrangement of each part in the apparatus will be described. The image forming apparatus according to the present embodiment is arranged from the lower side of the main body 30 to the feeding cassette 4, the exposure device 6, the process cartridges 1a to 1d, the intermediate transfer belt 2, and the discharge tray. 7 are arranged in this order.

  Here, the intermediate transfer belt 2 is stretched by stretching rollers 2e, 2f, and 2g. Among these, the stretching roller 2f is a tension roller that directly applies a stretching force to the intermediate transfer belt 2. A transfer cleaner 50 having a cleaning blade 50a for scraping off untransferred toner on the intermediate transfer belt 2 is disposed in the vicinity of the tension roller 2f. The cleaning blade 50a contacts the intermediate transfer belt 2 at a predetermined angle, but rotates around a support shaft 50b provided in the transfer cleaner 50 so that the cleaning blade 50a does not pull in following the conveyance of the intermediate transfer belt 2. Move.

  In the main body 30, a power supply (not shown) and a main electrical board (not shown) for controlling the entire image forming apparatus are arranged. Further, an electrical board 31 for applying a transfer bias to the primary transfer rollers 2 a to 2 d and the secondary transfer roller 3 is disposed above the intermediate transfer belt 2 and below the discharge tray 7. Here, the discharge tray 7 has a curved surface inclined upward from the upstream side to the downstream side in the discharge direction from the discharge conveyance means 21, and is formed between the discharge tray 7 and the intermediate transfer belt 2. An electrical board 31 is arranged in the space.

  Next, a method for positioning the intermediate transfer unit 2A having the intermediate transfer belt 2 in the set state on the main body will be described.

  The intermediate transfer belt 2 is stretched by stretching rollers 2e and 2g and a tension roller 2f, and a transfer frame 2h for supporting the rollers 2e to 2g and the primary transfer rollers 2a to 2d is disposed. The intermediate transfer belt 2, primary transfer rollers 2a to 2d, stretching rollers 2e and 2g, tension roller 2f, transfer frame 2h and the like are unitized as an intermediate transfer unit 2A.

  The intermediate transfer unit 2A is swingably supported with respect to the discharge tray 7 (described later). However, the intermediate transfer unit 2A is higher than the one-side main body side plate 11 (described later) with a main body side plate fitting portion 11b (described later) on the tension roller 2e side. The right and left direction is restricted. On the tension roller 2f side, a seating surface 2i provided on the transfer frame 2h is brought into contact with a bending plane 11d (described later) of the main body side plate 11 to regulate the height direction.

  The transfer frame 2h is provided with seating surfaces 2j on the tension roller 2e side and the tension roller 2f side, respectively, and the discharge frame 7a has a "<" shape protruding from the discharge frame 7a at a position opposite to the seating surface 2j. An elastic member such as an end of the torsion coil spring 7b or a leaf spring is disposed.

  With the above configuration, on one side of the main body side plate 11 (described later), the end portions of the two torsion coil springs 7b of the discharge frame 7a are placed on the seating surface 2j provided at the corresponding position of the end portions of the torsion coil springs 7b of the transfer frame 2h. Contact with a predetermined biasing force. As a result, the intermediate transfer unit 2A is positioned in the height and left-right direction by the main body side plate fitting portion 11b on the tension roller 2e side, and the seat surface 2i of the transfer frame 2h is the bending plane of the main body side plate 11 on the tension roller 2f side. Positioning in the height direction is made in contact with 11d (described later). The opposite side plate side of the main body side plate 11 has the same configuration.

  Next, the characteristic structure of the 1st rotation part of this Embodiment and a 2nd rotation part is demonstrated.

  FIG. 2 is a cross-sectional view showing a state where the first rotating part is opened, and FIG. 3 is a cross-sectional view showing a state where the second rotating part is opened.

  As shown in FIG. 2, a fixing frame 35 as an example of a rotation unit is provided with a part of a paper path C as an example of a fixing device 5 and a sheet conveyance path, and a support shaft 101 provided in the main body 30. It is set as the structure which can be rotated toward an apparatus side surface by using as a fulcrum. Accordingly, when the sheet P sent out from the cassette 4 by the pickup roller 8 is jammed during conveyance and stays in the paper path C, or when the sheet P is jammed in the fixing device 5, fixing is performed. The frame 35 is opened to perform a paper jam processing.

  The secondary transfer roller 3 is rotatably held by a holder 3b and is urged toward the intermediate transfer belt 2 by a compression spring 3a. The secondary transfer roller unit 3, the compression spring 3a, and the holder 3b constitute a secondary transfer roller unit 3c. Further, the secondary transfer roller unit 3c is swingably attached to the apparatus main body by a support shaft 3d. The support shaft 3d is disposed at a position where the secondary transfer roller 3 is separated from the intermediate transfer belt 2 when the secondary transfer roller unit 3c becomes substantially upright due to its own weight when the fixing frame 35 is opened.

  Further, between the secondary transfer roller unit 3c and the fixing frame 35, a main body side plate (11 in FIG. 4) and a side plate (not shown) opposite thereto are connected to form a reinforcing member constituting a part of the main body frame. 36 is arranged. The reinforcing member 36 has openings (not shown) at both ends in the longitudinal direction.

  On the other hand, a “<”-shaped wire spring 35 b as an example of a contact / separation means is fixed to the fixing frame 35 at positions opposite to the openings at both ends in the longitudinal direction of the reinforcing member 36. When the fixing frame 35 is closed, the wire spring 35b urges the holder 3b through an opening (not shown) to rotate the secondary transfer roller unit 3c about the support shaft 3d. The secondary transfer roller unit 3c is abutted against a restriction portion at a predetermined position (not shown), and positioning is performed. That is, as the fixing frame 35 is opened and closed, the secondary transfer roller 3 comes in contact with the intermediate transfer belt 2.

  With the above configuration, when the fixing frame 35 is opened as shown in FIG. 2, the paper path C is opened because the secondary transfer roller 3 is separated from the intermediate transfer belt 2. Therefore, when the sheet P is jammed before and after the nip portion between the secondary transfer roller 3 and the intermediate transfer belt 2, the jamming process can be easily performed.

  If the sheet P stays in the fixing device 5 and a paper jam occurs, when the fixing frame 35 is opened, the secondary transfer roller 3 is separated from the intermediate transfer belt 2 and the paper path C is opened. The sheet P can be pulled out while holding the sheet P in the container 5. Therefore, if the nip of the roller pair formed in the fixing device 5 is released by operating a pressure release lever (not shown) in the fixing device 5, the paper jam processing of the sheet P remaining in the fixing device 5 is easily performed. be able to.

  Further, as shown in FIG. 3, the discharge tray 7 is configured as a discharge unit 51 as an example of a second rotating portion integrally with the discharge frame 7a. The discharge unit 51 is supported so as to be rotatable with respect to the apparatus main body with a support shaft 100 provided on the side opposite to the fixing frame 35 as a fulcrum. The intermediate transfer belt 2 is engaged with the discharge unit 51 by an engaging portion (not shown). Therefore, when the discharge unit 51 is opened with the support shaft 100 provided on the main body 30 as a fulcrum, the intermediate transfer belt 2 is released in conjunction with the discharge unit 51. Therefore, when the process cartridges 1a to 1d, which are consumables, are exchanged, the process cartridges 1a to 1d can be accessed only by the opening operation of the discharge unit 51.

  Next, a characteristic configuration of the present embodiment will be described.

  FIG. 4 is an explanatory view of the operation of the main part from the state in which the second rotating part is opened until it is set at a predetermined position.

  4A to 4C, reference numeral 11 denotes one side of the main body side plate that supports the discharge tray 7, the intermediate transfer unit 2A, and the like (the left side plate when the opening direction of the fixing frame 35 is the front). In the main body side plate 11, a guide portion 11a for guiding the intermediate transfer unit 2A when the discharge tray 7 is opened and closed and a fitting portion 11b for positioning are formed in the vicinity of the secondary transfer roller 3. Further, when the discharge tray 7 and the fixing frame 35 are closed, a locking portion 11c of the intermediate transfer unit 2A is formed so that the intermediate transfer unit 2A is not separated by the pressure of the secondary transfer roller 3.

  In the process cartridges 1a to 1d, ball bearings 30a to 30d are disposed at both axial ends of the photosensitive drums 10a to 10d, and the outer rings of the ball bearings 30a to 30d are connected to the drum guide portions 31a to 31d of the main body side plate 11, respectively. After being guided to the fitting portions 32a to 32d while being guided, it is locked by a lock member (not shown). That is, the process cartridges 1 a to 1 d are configured to be directly positioned on the main body side plate 11.

  The intermediate transfer unit 2A is swingably attached to the discharge unit 51. When the discharge unit 51 is opened with the support shaft 100 as a fulcrum, as shown in FIG. The discharge unit 51 is held in a state in which the discharge unit 51 is opened at a predetermined angle by a damper member provided on the door and a lock member for restricting opening. In a state where the discharge unit 51 is not opened, the boss 2k provided on the intermediate transfer unit 2A is guided by the guide 7c of the discharge frame 7a, and the intermediate transfer unit is incorporated. Further, on the front end side of the discharge unit 51 (opposite side of the support shaft 100), it engages with the claw portion 7d of the discharge tray 7 inside the lock member 2m of the intermediate transfer unit 2A. Thus, the intermediate transfer unit 2A is prevented from falling off the discharge unit 51, and the engagement of the lock member 2m is released to improve the replacement workability of the intermediate transfer unit 2A.

  Here, the intermediate transfer unit 2A tends to drop in the closing direction of the discharge unit 51 by its own weight, but as described above, the open position is held by the damper member and the open restriction lock member (not shown) and the intermediate transfer unit 2A. The boss 2k contacts the wall surfaces 7d and 7e of the guide 7c of the discharge tray 7 and maintains the posture away from the discharge unit 51 in a range where the lock member 2m engages with the claw portion 7d.

  FIG. 4B shows a state when the discharge unit 51 of FIG. 4A is held from the open position until the primary transfer plane of the intermediate transfer unit 2A is further inclined from the horizontal with the support shaft 100 as a fulcrum. . The intermediate transfer unit 2A is rotated and closed while moving to the secondary transfer roller 3 side while the boss 2k is in contact with the wall surfaces 7d and 7e of the guide 7c by its own weight from the open state. The amount of movement is set by play between the lock member 2m and the claw portion 7d.

  Here, reference numeral 2l denotes a ball bearing which is a positioning member for the main body side plate 11 of the intermediate transfer unit 2A, and shows one disposed coaxially with the stretching roller 2e at both ends. While the intermediate transfer unit 2A is being closed as described above, the outer ring of the ball bearing 21 is in contact with the guide portion 11a of the main body side plate 11, and the fitting portion 11b and the enlarged fitting portion 11c as shown in FIG. The end of the torsion coil spring 7b is brought into contact with the seating surface 2j with a predetermined urging force, and the intermediate transfer unit 2A is positioned on the secondary transfer roller 3 side.

  Further, as described above, the seating surface 2i of the transfer frame 2h is brought into contact with the bending plane 11d of the main body side plate 11 on the opposite side (support shaft 100 side) of the secondary transfer roller 3, and positioning in the height direction is performed. Then, the end of the torsion coil spring 7b of the discharge unit 51 comes into contact with the seat surface 2j, and the intermediate transfer unit 2A is fixed.

  FIG. 4C shows a state in which the fixing frame 35 is closed after the discharge unit 51 is fixed to the main body. When the fixing frame 35 is closed, the wire spring 35b urges the holder 3b as described above to rotate the secondary transfer roller unit 3c about the support shaft 3d. Then, the secondary transfer roller 3 is brought into contact with the tension roller 2e coaxial with the ball bearing 21 which is the main positioning member of the intermediate transfer unit 2A via the intermediate transfer belt 2.

  Here, in a state where the discharge unit 51 and the fixing frame 35 are closed, the tension roller 2e of the secondary transfer roller 3 is secured to the main body side plate 11 to ensure engagement with the outer ring of the ball bearing 2l of the intermediate transfer unit 2A. A locking portion 11c is formed to be fitted with an excess of θ in the figure with respect to the pressure direction. As a result, the ball bearing 21 does not come off from the fitting portion 11b, and the end of the torsion coil spring 7b abuts against the seat surface 2j with a predetermined biasing force, thereby positioning the intermediate transfer unit 2A with respect to the main body side plate 11. Accuracy is guaranteed.

  Next, a characteristic configuration of the present embodiment will be described with reference to FIGS.

  FIG. 5A shows a cross section in the vicinity of the ball bearings 30a to 30d in the process cartridges 1a to 1d described above. FIG. 5B is an overall schematic configuration diagram for explaining the peripheral configuration of a bearing guide 62 to be described later. FIG. 4 is an enlarged view showing details of a peripheral configuration of the bearing guide 62.

  5 (a) and 5 (b), 61 is a tension bearing. The tension bearings 61 are provided at both ends of the tension roller 2f in the axial direction, and one of them is shown in the figure. In addition, a radial bearing member (not shown) such as a ball bearing is press-fitted into the tension bearing 61 in order to smoothly rotate the tension roller 2f. The core bar of the tension roller 2f is fitted inside the bearing member.

  Further, the bearing guide 62 is directly fixed to the transfer frame side surface 2k formed integrally with the transfer frame 2h (in the drawing, one of the transfer frame side surface 2k and the bearing guide 62 is shown). A tension bearing 61 is disposed inside the bearing guide 62. Then, the upper rib 61a and the lower rib 61b formed integrally with the tension bearing 61 slide with the inner upper wall 62a and the inner lower wall 62b of the bearing guide 62, respectively. Here, the tension bearing 61 is fitted with a boss 21 having a long hole 61c integrally formed with the transfer frame side surface 2k, and the upper rib 61a and the lower rib 61b of the tension bearing 61 are located within the bearing guide 62 in the vicinity of the tension roller 2f. The upper wall 62a and the inner lower wall 62b are fitted. Thereby, the sliding direction of the tension bearing 61 is regulated.

  Reference numeral 63 denotes a tension spring composed of a compression spring for applying a predetermined tension to the intermediate transfer belt 2. One end surface of the tension spring 63 is seated on a seat surface (not shown) formed integrally with the transfer frame 2h, and the other end surface of the tension spring 63 is seated (not shown) formed integrally with the tension bearing 61. Sit on.

  With the above configuration, the spring force of the tension spring 63 is applied as the tension of the intermediate transfer belt 2 via the tension bearing 61 and the tension roller 2f.

  A foam material 64 as an elastic member is attached to the upper surface of the bearing guide 62. The foam material is sandwiched between the upper surface of the discharge frame 7a and the bearing guide 62 constituting the discharge unit 51 and compressed by a predetermined amount. The pressing force from the upper surface of the bearing guide 62 is determined by the amount of compression. A seating surface 62c is formed on the lower surface of the bearing guide 62, and the seating surface 62c abuts on the bending plane 11d of the main body side plate 11 to position the intermediate transfer unit 2A in the height direction.

  The pressing force generated by sandwiching the foam material 64 between the discharge frame 7a and the upper surface of the bearing guide 62 and compressing the foam material 64 is set so as not to prevent the tension bearing 61 and the bearing guide 62 from sliding. It is defined by a compression amount of 64.

  Further, in order to fix the transfer cleaner 50 to the tension bearing 61, a mounting surface 50d is integrally formed on the holder 50c constituting the transfer cleaner 50. The mounting surface 50d is fixed to the seat surface 61c of the tension bearing 61 with screws 61d.

  As described above, since the transfer cleaner 50 is directly fixed to the tension bearing 61 configured to support the tension roller 2f and apply a predetermined tension to the intermediate transfer belt 2, the temperature, humidity, Even if the peripheral length of the intermediate transfer belt 2 expands or contracts due to durability factors or the like, the contact position and the contact angle of the cleaning blade 50a in the transfer cleaner 50 with respect to the tension roller 2f are maintained. Thereby, the cleaning performance is stabilized, and the output image is stabilized.

  In addition, according to the above configuration, the foam material 64 is compressed and the engagement force between the tension bearing 61 and the bearing guide 62 is forcibly removed by the compression force, thereby generating the conveyance of the intermediate transfer belt 2. The fine vibrations of the cleaning blade 50a that can not be suppressed even by the backlash can be absorbed in the foam material 64.

  This eliminates noise associated with the vibration of the cleaning blade 50a, slipping of untransferred toner at the contact portion of the cleaning blade 50a, retransfer of the slipping toner, and the like, thereby stabilizing the apparatus quality and image quality.

<Embodiment 2>
Next, a characteristic configuration of the second embodiment of the present invention will be described with reference to FIGS. 6 (a) and 6 (b). 6 (a) and 6 (b), elements having the same reference numerals as those in FIGS. 5 (a) and 5 (b) have the same configuration, and a description thereof will be omitted.

  FIG. 6A shows a cross section in the vicinity of the ball bearings 30a to 30d in the process cartridges 1a to 1d described above, and an overall schematic configuration diagram for explaining the peripheral configuration of the bearing guide 62, and FIG. 6B shows the bearing guide. It is an enlarged view which shows the detail of the surrounding structure of 62. FIG.

  In FIGS. 6A and 6B, 62 d is an abutting portion formed integrally with the upper surface of the bearing guide 62. On the upper surface of the contact portion 62d, an elastic member such as an end portion of a “<”-shaped torsion coil spring 7k protruding from the discharge frame 7a or a leaf spring is disposed.

  The bearing surface 62c of the bearing guide 62 abuts on the bending plane 11d of the main body side plate 11, and the end of the torsion coil spring 7k of the discharge frame 7a abuts on the upper surface of the abutting portion 62d of the bearing guide 62. Positioning in the vertical direction is performed.

  Note that the spring force by the end of the torsion coil spring 7k is set to such an extent that the sliding of the tension bearing 61 and the bearing guide 62 is not hindered.

  According to the above configuration, the bearing guide 62 is pressed in the direction of the bending plane 11d of the main body side plate 11 by the spring force of the torsion coil spring 7k, and the fitting play between the tension bearing 61 and the bearing guide 62 is forcibly eliminated. As a result, the fine vibration of the cleaning blade 50a that occurs with the conveyance of the intermediate transfer belt 2 is reduced, and noise reduction and apparatus quality and image quality are stabilized.

  Further, the end portion of the torsion coil spring 7k can be disposed in a space formed between the discharge frame 7a and the discharge tray 7, so that the space in the apparatus can be effectively used. In particular, if it is necessary to press the bearing guide 62 with a desired pressure, the degree of freedom of the spring shape is increased, such as changing the torsion coil spring 7k to a compression coil spring, and a more preferable arrangement is possible.

  The present invention is effective for an image forming apparatus in which a transfer cleaner is fixed to a bearing member that rotatably supports a tension roller that applies tension to a belt body.

1 is an overall configuration diagram of an image forming apparatus according to the present invention. It is sectional drawing which shows the state which open | released the 1st rotation part. It is sectional drawing which shows the state which open | released the 1st rotation part and the 2nd rotation part. It is operation | movement explanatory drawing of a 2nd rotation part, and shows the state which closes with respect to an apparatus main body in order of (a)-(c). 1A is an overall schematic configuration diagram of an image forming apparatus according to Embodiment 1 of the present invention, and FIG. 1B is an enlarged view of a main part of the image forming apparatus. (A) is an overall schematic configuration diagram of an image forming apparatus according to Embodiment 2 of the present invention, and (b) is an enlarged view of the main part of the image forming apparatus.

Explanation of symbols

1a to 1d Process cartridge (photosensitive drum unit)
2 Intermediate transfer belt (transfer belt)
2A Intermediate transfer unit (transfer belt unit)
2f Tension roller 5 Fixing device (fixing means)
7k torsion coil spring (spring material)
8 Pickup roller (paper feeding means)
11 Body side plate 50 Transfer cleaner (cleaning means)
51 Discharge unit (paper discharge means)
61 Tension bearing (bearing member)
62 Bearing guide (guide member)
62c Guide member seating surface 64 Foam material (elastic foam material)

Claims (8)

A transfer belt unit comprising: a tension roller that applies tension to the transfer belt; a cleaning unit disposed at a position opposite to the tension roller; and a bearing member that rotatably supports the tension roller and fixes the cleaning unit;
In an image forming apparatus including a paper feeding unit, a photosensitive drum unit, a fixing unit, and a paper discharging unit,
An image forming apparatus, wherein the cleaning unit is elastically supported from a direction substantially perpendicular to a sliding direction of the bearing member.   A guide member that regulates the moving direction of the bearing member is fixed in the transfer belt unit, and one seating surface of the guide member is rigidly supported from a direction substantially perpendicular to the moving direction of the bearing member by the guide member. 2. The image forming apparatus according to claim 1, wherein the other seating surface is elastically supported.   The image forming apparatus according to claim 1, wherein an elastic foam material is used as the elastic support unit.   The image forming apparatus according to claim 1, wherein a spring material is used as the elastic support unit.   The transfer belt unit is elastically supported at two points on each side with respect to both side plates of the main body, and the cleaning unit is elastically supported independently of the transfer belt unit other than the elastic support portion of the transfer belt unit. The image forming apparatus according to 1 or 2.   The image forming apparatus according to claim 1, wherein the cleaning unit is elastically supported in a direction passing through a center of a cross section of the tension roller.   The image forming apparatus according to claim 1, wherein the transfer belt is an intermediate transfer belt.   The discharge means is rotatably supported by the apparatus main body, and the transfer belt unit is swingably supported by the discharge means and is positioned directly with respect to the main body side plate. Item 2. The image forming apparatus according to Item 1.

Images