JP2009222972A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for preventing color shift. <P>SOLUTION: The image forming apparatus includes a first cam 630 that inclines a tension roll 230, thereby preventing meandering of a transfer belt 210. The first cam 630 has a color face 631 for bringing a first state in which primary transfer rolls 240C, 240M, 240Y, and 240K are pressed, and a monochrome face 632 for bringing a second state in which a primary transfer roll 240K is pressed and the primary transfer rolls 240C, 240M, and 240Y are separated from corresponding photoreceptor drums 110C, 110M and 110Y respectively via a primary transfer device 200. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

As a conventional image forming apparatus, for example, there is an image forming apparatus described in Patent Document 1. An image forming apparatus described in Patent Document 1 includes a transfer belt to which a toner image formed on a photosensitive drum is transferred, a meander correcting roller that corrects the meandering of the transfer belt, and an elliptic cam that regulates the movement of the meander correcting roller. And had. In the image forming apparatus described in Patent Document 1, the movement of the meandering correction roller is controlled by the elliptic cam, and the meandering correction roller swings and the transfer belt is prevented from meandering.
JP 05-301651A

  The present invention has been made based on the technical background as described above, and an object of the present invention is to provide a technique for preventing the occurrence of color misregistration.

  According to a first aspect of the present invention, the first image is formed in an endless belt shape and is moved from the first image holding means for holding the first image and the second image holding means for holding the second image. A conveying means for conveying the image and the second image; an applying means provided inside the conveying means for applying a predetermined tension to the conveying means; provided inside the conveying means; The first image holding means is pressed to transfer the first image from the first image holding means to the conveying means, and provided inside the conveying means, A transfer device having a second transfer means for transferring the second image from the second image holding means to the transfer means under pressure applied to the second image holding means via the transfer means; Suppression for tilting the means to suppress the meandering of the conveying means A step, and the suppression means pressurizes the first transfer means and a first surface for pressing the first transfer means and the second transfer means, and pressurizes the first transfer means. And an image forming apparatus comprising: a second surface for bringing the second transfer means away from the second image carrier through the conveying device.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the transfer device changes from the first state to the second state, as the applying unit moves, A moving means for moving the second transfer means is provided.

  The invention described in claim 3 is the invention described in claim 1 or 2, further comprising support means that is fixed to the housing and supports the transport device in the first state. Features.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, a circumferential surface that supports the conveying device in the second state is interlocked with the suppressing means. It has the supporting member which has.

  The invention according to claim 5 is the invention according to claim 4, wherein the suppressing means and the support member are arranged coaxially.

  According to the first aspect of the present invention, it is possible to prevent the occurrence of color misregistration as compared with the case where the present invention is not applied.

  According to the second aspect of the present invention, it is possible to prevent the occurrence of color misregistration as compared with the case where the present invention is not applied.

  According to the third aspect of the present invention, compared with the case where the present invention is not applied, it is possible to improve the accuracy of overlaying the first image and the second image.

  According to the invention described in claim 4, it is possible to suppress meandering of the conveying means in a predetermined case with a simple configuration as compared with the case where the present invention is not applied.

  According to the fifth aspect of the present invention, the support member can be arranged in a space-saving manner as compared with the case where the present invention is not applied.

(Color printer configuration)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an outline of a color printer. Since the developing devices 100C, 100M, 100Y, and 100K are provided in the same manner, the developing device 100K will be mainly described with reference to the drawings.

  A color printer (image forming apparatus) 1 includes a control unit (not shown), a main body housing (housing) 10, a laser beam scanning device 20, a toner cartridge 30, a belt cleaner 40, a discharge unit 50, a support unit (support means) 60, Developing devices 100C, 100M, 100Y, and 100K, a primary transfer device (conveyance device) 200, a paper feeding device 300, a secondary transfer device 400, a fixing device 500, a steering device 600, and the like are provided. The color printer 1 prints an overlapped image of four color components of cyan (C), magenta (M), yellow (Y), and black (K) on a sheet (not shown). Details of the support 60 and the steering device 600 will be described later.

  In the color printer 1, image data is supplied from a not-shown image output device such as a PC (Personal Computer) or an image reading device to a control unit not shown via a predetermined communication line. Based on the supplied image data, the control unit issues an image formation control command to the laser beam scanning device 20, the developing device 100K, and the like. Further, the control unit controls the entire operation of the color printer 1 including the image forming operation.

  In the color printer 1, the developing devices 100 </ b> C, 100 </ b> M, 100 </ b> Y, and 100 </ b> K are arranged side by side along the primary transfer device 200 at predetermined intervals for each color of C, M, Y, and K. The developing devices 100C, 100M, 100Y, and 100K are disposed above the laser beam scanning device 20. The developing device 100K includes a photosensitive drum (first image holding unit) 110K that receives laser light irradiation from the laser light scanning device 20.

  The laser beam scanning device 20 scans the laser beam according to the image data supplied from the control unit. The laser beam scanning device 20 deflects and scans the laser beam modulated according to the image data of each color and irradiates the photosensitive drum 110K of the developing device 100K. An electrostatic latent image is formed on the photosensitive drum 110K by the laser beam scanned by the laser beam scanning device 20.

  The photosensitive drum 110K rotates in the direction of arrow A. Around the photosensitive drum 110K, there are a cleaning device 120K for cleaning the surface of the photosensitive drum 110K, a charger 130K for charging the surface of the photosensitive drum 110K, and an electrostatic latent image formed on the surface of the photosensitive drum 110K. A developing device 140K for developing an image is provided in this order along the arrow A direction.

  The toner cartridge 30 supplies each color component toner to the developing devices 100C, 100M, 100Y, and 100K.

  In the developing device 100K, the rotating photosensitive drum 110K is charged by the charger 130K, and the surface thereof is irradiated with laser light from the laser beam scanning device 20, whereby an electrostatic latent image corresponding to black image data is formed. It is formed. Next, when the electrostatic latent image passes through the developing device 140K, black toner is supplied from the developing device 140K to the surface of the photosensitive drum 110K, and the toner remains only on the electrostatic latent image on the surface. The (first image) is developed. C, M, and Y toner images (second images) are formed on the photosensitive drums (second image holding means) 110C, 110M, and 110Y, respectively.

  Next, the toner image on the photosensitive drum 110 </ b> K is primarily transferred onto a transfer belt (conveying means) 210 of the primary transfer device 200 that circulates and rotates in the direction of arrow B. After the primary transfer, toner remains on the surface of the photosensitive drum 110K. The remaining toner is scraped off from the surface of the photosensitive drum 110K by the cleaning device 120K.

  The primary transfer device 200 receives the toner image from the photosensitive drum 110K to the transfer belt 210 as described above, and performs the primary transfer process, and passes through the developing devices 100C, 100M, 100Y, and 100K. The toner images of the respective colors are transferred onto the transfer belt 210 in a multiple manner. The transfer belt 210 is wound around the drive roll 220 and the tension roll (applying means) 230 with a predetermined tension applied, and is circulated and rotated by the drive roll 220 in the direction of arrow B at a predetermined speed. The drive roll 220 also has a function as a backup roll.

  On the inner peripheral side of the transfer belt 210, a primary transfer roll 240 (first transfer means) K that rotates with the photoconductive drum 110K is sandwiched between the photoconductive drum 110 and the photoconductive drum 110 of the developing device 100K. It is provided freely. A belt cleaner 40 that scrapes off the toner remaining on the surface of the transfer belt 210 is provided on the outer peripheral side of the transfer belt 210. Details of the primary transfer device 200 will be described later.

  The paper feed device 300 conveys the paper toward the secondary transfer device 400, a paper feed storage unit 310 on which a plurality of papers are stacked, an extraction roll (not shown) that pulls out one sheet from the paper feed storage unit 310, and A pair of conveyance rolls 320 to be aligned, and a pair of registration rolls 330 that are aligned in the conveyance direction of the paper and are fed to the secondary transfer device 400 at a predetermined timing. A paper transport path 340 is formed.

  The secondary transfer apparatus 400 includes a secondary transfer roll 410 that sandwiches the transfer belt 210 with the drive roll 220 and rotates with the drive roll 220 while generating transfer pressure. In the secondary transfer device 400, the sheet conveyed through the sheet conveyance path 340 from the sheet storage unit 310 is positioned between the transfer belt 210 and the secondary transfer roll 410 in synchronization with the toner image on the transfer belt 210. The toner image is secondarily transferred onto the sheet. The second-transferred sheet is sent to the fixing device 500 by the conveyance belt 420.

  The fixing device 500 fixes the secondary transfer image on the paper by conveying the paper while being heated between the heating roll 510 and the pressure roll 520 while being heated. The sheet on which the secondary transfer image is fixed is discharged to a discharge unit 50 provided on the upper portion of the color printer 1.

(Color printer operation)
Next, the operation of the color printer 1 will be described. The color printer 1 sequentially primary-transfers the C, M, Y, and K color toner images formed on the surfaces of the respective photoconductive drums 110C, 110M, 110Y, and 110K to the transfer belt 210 sequentially. Next, the color printer 1 uses the secondary transfer device 400 to secondarily transfer the primary transfer image on the transfer belt 210 onto the paper conveyed from the paper supply device 300. Then, the color printer 1 sends the sheet to the fixing device 500, fixes the secondary transfer image on the sheet, and discharges the sheet to the discharge unit 50.

(Configuration of primary transfer device and steering device)
Next, the primary transfer device 200 and the steering device 600 will be described with reference to the drawings. FIG. 2 is a perspective view showing the primary transfer device and the steering device. 3 is a cross-sectional view taken along line XX in FIG. In FIG. 2, a frame (moving means) 250 (to be described later) provided on the front side of FIG. 2 is omitted.

  As shown in FIG. 2, the primary transfer device 200 includes a transfer belt 210, a drive roll 220, a tension roll 230, primary transfer rolls 240 </ b> C, 240 </ b> M, 240 </ b> Y, 240 </ b> K, and a frame 250. The primary transfer device 200 receives a toner image from the photosensitive drums 110C, 110M, 110Y, and 110K to the transfer belt 210 and performs a primary transfer process. The color printer 1 includes a support portion 60 that supports the primary transfer device 200 as shown in FIG.

  As shown in FIG. 2, the transfer belt 210 is formed in an endless belt shape. The transfer belt 210 is wound around the drive roll 220 and the tension roll 230 in a state where a predetermined tension is applied. Since the transfer belt 210 is wound only around the drive roll 220 and the tension roll 230, the width between the transfer belts 210 is narrower than when a plurality of tension rolls are provided. The transfer belt 210 is circulated and rotated in the direction of arrow B at a predetermined speed by the drive roll 220.

  As shown in FIG. 2, the drive roll 220 is rotatably supported at both ends by a frame 250 and is provided inside the transfer belt 210. The driving roll 220 drives the transfer belt 210 to circulate and rotate the transfer belt 210 in the arrow B direction. The drive roll 220 also has a function as a backup roll.

  As shown in FIG. 2, the tension roll 230 is provided inside the transfer belt 210 with one end rotatably supported by a cam follower 650 described later and the other end rotatably supported by a frame 250. The tension roll 230 applies a predetermined tension to the transfer belt 210.

  As shown in FIG. 2, the primary transfer rolls (second transfer means) 240C, 240M, 240Y and the primary transfer roll 240K are rotatably supported by a frame 250 and are provided inside the transfer belt 210. Yes. The primary transfer rolls 240C, 240M, 240Y, and 240K are provided at positions facing the photosensitive drums 110C, 110M, 110Y, and 110K of the developing devices 100C, 100M, 100Y, and 100K with the transfer belt 210 interposed therebetween.

  The primary transfer rolls 240C, 240M, 240Y, and 240K pressurize the photosensitive drums 110C, 110M, 110Y, and 110K through the transfer belt 210, and the toners of the respective colors formed on the photosensitive drums 110C, 110M, 110Y, and 110K. The image is transferred to the transfer belt 210.

  The frame 250 is provided on both sides of the transfer belt 210 as shown in FIG. The frame 250 rotatably supports the drive roll 220 and the primary transfer rolls 240C, 240M, 240Y, and 240K. The frame 250 is provided with an opening 251 through which one end of the tension roll 230 passes with a predetermined gap, and a bearing 252 that rotatably supports the other end of the tension roll 230.

  2 and 3, the steering device 600 includes a steering motor 610, an output shaft (shaft) 620, a first cam (suppressing means) 630, a second cam (support member) 640, and a cam follower 650. And.

  The steering device 600 prevents the transfer belt 210 from meandering by tilting the tension roll 230. Further, the steering device 600 tilts the conveying device 200 from the state of pressing the primary transfer rolls 240C, 240M, 240Y, and 240K (first state) to pressurize the primary transfer roll 240K, thereby pressing the primary transfer roll 240K. 240C, 240M, and 240Y are in a state of being separated from the photoconductive drums 110C, 110M, and 110Y (second state).

  If an image is formed in a state where the primary transfer rolls 240C, 240M, 240Y, and 240K are pressed, an image of four colors can be formed. On the other hand, when the primary transfer roll 240K is pressurized and the images are formed with the primary transfer rolls 240C, 240M, and 240Y separated from the photosensitive drums 110C, 110M, and 110Y, only a black image is formed.

  When the primary transfer rolls 240C, 240M, and 240Y are separated as described above, the load on the primary transfer rolls 240C, 240M, and 240Y is reduced as compared with the case where the primary transfer rolls 240C, 240M, and 240Y are not separated.

  Here, the state in which the primary transfer rolls 240C, 240M, 240Y, and 240K are pressurized is hereinafter referred to as a color mode. On the other hand, a state in which the primary transfer roll 240K is pressurized and the primary transfer rolls 240C, 240M, and 240Y are separated from the photosensitive drums 110C, 110M, and 110Y is hereinafter referred to as a monochrome mode.

  The steering device 600 detects detection result information of a home position detection unit (not shown) that detects a home position mark (not shown) provided on the transfer belt 210 and the position in the belt width direction of the side end portion of the transfer belt 210. It is controlled by the control unit based on detection result information of a belt end position detection sensor (not shown).

  The steering motor 610 is a motor such as a stepping motor. The steering motor 610 is controlled by a control unit based on predetermined information. The steering motor 610 rotates the output shaft 620. As shown in FIG. 3, a first cam 630 and a second cam 640 are attached to the output shaft 620. That is, the first cam 630 and the second cam 640 are arranged coaxially. Therefore, the first cam 630 and the second cam 640 are interlocked.

  As shown in FIGS. 2 and 3, the first cam 630 is provided at one end of the output shaft 620 and contacts the cam follower 650. The first cam 630 has a color surface (first surface) 631 for switching to the color mode and a monochrome surface (second surface) 632 for switching to the monochrome mode. The first cam 630 is a member for suppressing the meandering of the transfer belt 210. The first cam 630 is a member for switching between the color mode and the monochrome mode.

  A state in which the color surface 631 is in contact with the cam follower 650 is a color mode. The color surface 631 is a surface having a different diameter. Therefore, when the contact position with the cam follower 650 changes within the range of the collar surface 631, one end of the tension roll 230 moves in the direction of arrow C in FIG. That is, the first cam 630 suppresses the meandering of the transfer belt 210 by tilting the tension roll 230 in the color mode. At this time, since one end of the tension roll 230 and the opening 251 have a predetermined gap, one end of the tension roll 230 does not contact the frame 250.

  A state in which the monochrome surface 632 is in contact with the cam follower 650 is a monochrome mode. The black and white surface 632 is formed at a position where the diameter is larger than that of the color surface 631. Therefore, one end of the tension roll 230 moves in the direction of arrow C in FIG. 3 more than in the color mode. That is, the tension roll 230 side of the transport apparatus 200 moves in the direction of arrow C, and the transport apparatus 200 is inclined.

  At this time, one end of the stretching roll 230 comes into contact with the frame 250. When one end of the tension roll 230 comes into contact with the frame 250, the frame 250 supports the primary transfer rolls 240C, 240M, 240Y, and 240K. Therefore, as the tension roll 230 moves, the primary transfer roll 240C, 240M and 240Y move. That is, the primary transfer rolls 240C, 240M, and 240Y are separated from the photosensitive drums 110C, 110M, and 110Y.

  The black and white surface 632 is a surface having a different diameter. Therefore, when the contact position with the cam follower 650 is changed within the range of the black and white surface 632, one end of the tension roll 230 further moves in the direction of arrow C in FIG. 3, and the transfer belt 210 meanders by tilting the tension roll 230. To suppress. That is, the first cam 630 suppresses the meandering of the transfer belt 210 in the black and white mode.

  As shown in FIG. 3, the second cam 640 is provided at the other end of the output shaft 620 and contacts the frame 250 in a predetermined case. The second cam 640 is formed in a semicircular shape and has a circumferential surface 641. Since the second cam 640 is formed in a semicircular shape, the second cam 640 does not contact the conveying device 200 in the color mode, and the circumferential surface 641 contacts the frame 250 of the conveying device 200 in the black and white mode. 200 is supported.

  The circumferential surface 641 is a surface having the same diameter. Therefore, even if the contact position with the frame 250 changes within the range of the circumferential surface 641, the position of the frame 250 does not change. Therefore, in the black and white mode, even if the output shaft 620 rotates and the height on one end side of the tension roll 230 changes, the height on the other end side of the tension roll 230 does not change. To do.

  When the output shaft 620 rotates, the second cam 640 moves the frame 250 in the arrow C direction from the state in which the circumferential surface 641 is not in contact with the frame 250 and the circumferential surface 641 contacts the frame 250. That is, the second cam 640 also has a function as a switching member for switching between the color mode and the monochrome mode. Accordingly, the rotation of the output shaft 620 causes the circumferential surface 641 of the second cam 640 to contact the frame 250 at the same time as the black and white surface 632 of the first cam 630 contacts the cam follower 650, thereby conveying the conveying device. The tension roll 230 side of 200 moves in the direction of arrow C, and the conveying device 200 is inclined.

  In addition, not only embodiment provided with the 2nd cam 640 but it is good also as a structure which supports the conveying apparatus 200 with support members, such as a solenoid.

  The cam follower 650 is provided at one end of the stretching roll 230 as shown in FIGS. The cam follower 650 is in contact with the first cam 630. The cam follower 650 supports the tension roll 230 in a rotatable manner.

  As shown in FIG. 3, the support unit 60 supports the frame 250 in the color mode. The support portion 60 is fixed to the main body housing 10 on the side where the second cam 640 is provided. Therefore, in the color mode, even if the output shaft 620 rotates and the height on one end side of the tension roll 230 changes, the height on the other end side of the tension roll 230 does not change, so the tension roll 230 is inclined. To do.

  As described above, the support unit 60 supports the frame 250 in the color mode. Therefore, the frame 250 is supported more stably than the case where the member that supports the frame 250 of the transport apparatus 200 is a member such as a cam that may change the contact state. As a result, the blur of the conveying device 200 is reduced in the color mode, and the accuracy of superimposing the toner images of the respective colors on the transfer belt 210 is increased.

  In addition, it is good not only when providing the support part 60, but it is good also as a structure which deform | transforms the 2nd cam 640 and supports the conveying apparatus 200 also in a color mode.

  The frame 250 is not limited to the case where the opening 251 and the bearing 252 are provided, and the frame 250 may be configured to rotatably support both ends of the stretching roll 230. In this case, the first cam 630 contacts the frame 250 to switch between the color mode and the black and white mode and suppress the meandering of the transfer belt 210.

(Operation of steering device)
Next, the operation of the steering device 600 will be described with reference to the drawings. FIG. 4 is a diagram illustrating the steering device in the color mode. FIG. 4A is a diagram of the transport device 200 and the steering device 600 viewed from the front side of FIG. FIG. 4B is a cross-sectional view of the transport device 200 and the steering device 600 as viewed from the front side of FIG. FIG. 5 is a diagram showing the steering device in the black and white mode. FIG. 5A is a view of the transport device 200 and the steering device 600 as seen from the front side of FIG. FIG. 5B is a cross-sectional view of the transfer device 200 and the steering device 600 as viewed from the front side of FIG.

  First, the color mode will be described with reference to FIG. When the color surface 631 of the first cam 630 contacts the cam follower 650, the color mode is set as shown in FIG. At this time, as shown in FIG. 4B, the second cam 640 is not in contact with the transport device 200, and the support unit 60 contacts the frame 250 to support the transport device 200.

  In the color mode, when the output shaft 620 rotates in the direction of the arrow D within the range of the color surface 631, the stretching belt 230 is inclined to prevent the transfer belt 210 from meandering. At this time, one end of the tension roll 230 does not contact the frame 250 because the opening 251 has a predetermined size. Further, since the second cam 640 is also formed in a semicircular shape, even if the output shaft 620 rotates within the range of the collar surface 631, it does not contact the frame 250.

  Next, the monochrome mode will be described with reference to FIG. When the first cam 630 and the second cam 640 rotate in the direction of arrow D from the state of FIG. 4, the black and white surface 631 of the first cam 630 contacts the cam follower 650 as shown in FIG. Is moved in the direction of arrow C. Further, as shown in FIG. 5B, the circumferential surface 641 of the second cam 640 comes into contact with the frame 250, and the tension roll 230 side of the transport device 200 is moved in the direction of arrow C, so that the second cam 640 is obtained. The circumferential surface 641 supports the conveying device 200.

  At this time, the stretching roll 230 on the first cam 630 side contacts the frame 250 and moves the frame 250 in the direction of arrow C. The second cam 640 contacts the frame 250 and moves the frame 250 in the direction of arrow C. Therefore, the primary transfer rolls 240C, 240M, and 240Y are separated from the photosensitive drums 110C, 110M, and 110Y. That is, the monochrome mode is set.

  In the monochrome mode, when the output shaft 620 rotates in the direction of the arrow D within the range of the monochrome surface 632, the tension roll 230 is inclined to prevent the transfer belt 210 from meandering. When the output shaft 620 rotates in the direction opposite to the arrow D direction, the monochrome mode is switched to the color mode.

  As described above, in the color printer 1, since the first cam 630 has the color surface 631 and the monochrome surface 632, it is possible to prevent the transfer belt 210 from meandering by tilting the tension roller 230 not only in the color mode but also in the monochrome mode. To do. Therefore, the transfer belt 210 is further prevented from meandering than the case where the transfer belt 210 is prevented from meandering only in the color mode. As a result, color misregistration is prevented from occurring in the formed image.

  The present invention can be used for an image forming apparatus such as a color printer, a FAX, a color copying machine, and an apparatus having these functions.

1 is a schematic configuration diagram illustrating an overview of a color printer. It is a perspective view which shows a primary transfer apparatus and a steering device. It is XX sectional drawing in FIG. It is a figure which shows the steering device in color mode. It is a figure which shows the steering device in monochrome mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Color printer, 10 ... Main body housing, 60 ... Support part, 110C, 110M, 110Y, 110K ... Photosensitive drum, 200 ... Primary transfer device, 210 ... Transfer belt, 230 ... Stretching roll, 240C, 240M, 240Y, 240K ... primary transfer roll, 250 ... frame, 620 ... output shaft, 630 ... first cam, 631 ... color surface, 632 ... monochrome surface, 640 ... second cam, 641 ... circumferential surface.

Claims (5)

The first image and the second image moved from the first image holding means for holding the first image and the second image holding means for holding the second image are formed in an endless belt shape. Conveying means, an applying means provided inside the conveying means for imparting a predetermined tension to the conveying means, and a first image holding means provided inside the conveying means via the conveying means A first transfer means for transferring the first image from the first image holding means to the transport means and an inner side of the transport means, and the second image via the transport means. A transport device having a second transfer unit that is pressurized by the image holding unit and transfers the second image from the second image holding unit to the transport unit;
A suppression means for suppressing the meandering of the conveying means by inclining the applying means,
The suppression means pressurizes the first transfer means and the first transfer means, and pressurizes the first transfer means to pressurize the first transfer means and the second transfer means. And a second surface for bringing the second transfer means into a second state in which the second transfer means is separated from the second image carrier.   The transport device includes a moving unit that moves the second transfer unit as the applying unit moves when the second state is changed from the first state to the second state. The image forming apparatus according to claim 1.   3. The image forming apparatus according to claim 1, further comprising a support unit that is fixed to the housing and supports the transport device in the first state. 4.   The image forming apparatus according to claim 1, further comprising: a support member having a circumferential surface that interlocks with the suppression unit and supports the conveyance device in the second state. apparatus.   The image forming apparatus according to claim 4, wherein the suppressing unit and the support member are arranged coaxially.

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