JP5895688B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses a configuration in which a tension member disposed immediately downstream of the primary transfer portion among the tension members that stretch the intermediate transfer belt is grounded.

JP 2007-114500 A

  An object of the present invention is to simplify the components that are attached to and detached from the apparatus main body.

  According to the first aspect of the present invention, an annular intermediate transfer body that conveys the image transferred at the first transfer position to the second transfer position by circulation and transfers the image to a recording medium at the second transfer position; Wrapped around the inner peripheral surface of the intermediate transfer member downstream of the first transfer position in the transport direction and upstream of the second transfer position in the transport direction, and applies tension to the intermediate transfer member by pushing the intermediate transfer member outward. A tension applying member, an intermediate transfer body and the tension applying member, a removable body integrally attached to the intermediate transfer body and the tension applying member, and the apparatus main body of the removable body In the mounted state with respect to the intermediate transfer body, the tension applying member is provided in the apparatus main body so as to come into contact with the tension applying member on the side of the intermediate transfer body, and the inner periphery of the intermediate transfer body is interposed via the tension applying member. Plane A contact member to release the load, which is an image forming apparatus comprising a.

  The invention according to claim 2 is the image forming apparatus according to claim 1, wherein the contact member is urged toward the tension applying member in a direction opposite to a pushing direction of the tension applying member.

  A third aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein the contact member also serves as a holding member that holds a detection unit that detects the image density of the intermediate transfer member.

  According to the first aspect of the present invention, the detachable body is attached to and detached from the apparatus main body as compared with the case where the detachable body is provided with a member that contacts the tension applying member and releases the charge on the inner peripheral surface of the intermediate transfer body. Simplification of components can be achieved.

  According to the structure of Claim 2 of this invention, compared with the case where it does not have this structure, the contact failure of a contact member and a tension | tensile_strength provision member can be suppressed.

  According to the configuration of the third aspect of the present invention, the number of components can be reduced as compared with the case where the detection unit is held using dedicated components.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a schematic diagram illustrating a state in which an intermediate transfer belt is separated from a photoreceptor in the configuration illustrated in FIG. 1. It is a perspective view which shows the structure of the transfer unit which concerns on this embodiment. It is a side view which shows the structure of the grounding mechanism which concerns on this embodiment. It is a perspective view which shows the structure of the grounding mechanism which concerns on this embodiment. FIG. 6 is a side view showing the configuration of the grounding mechanism during the take-out operation of the transfer unit according to the present embodiment. It is a side view showing the configuration of the grounding mechanism during the mounting operation of the transfer unit according to the present embodiment. It is a side view which shows the structure of the grounding mechanism which concerns on a modification.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

(Configuration of image forming apparatus 10)
First, the configuration of the image forming apparatus 10 according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 11 in which each component is provided. Inside the image forming apparatus main body 11, a storage unit 12 that stores a recording medium P such as paper, an image forming unit 14 that forms an image on the recording medium P, and a recording medium from the storage unit 12 to the image forming unit 14. A conveyance unit 16 that conveys P and a control unit 20 that controls the operation of each unit of the image forming apparatus 10 are provided. In addition, a discharge unit 18 for discharging the recording medium P on which an image is formed by the image forming unit 14 is provided on the upper portion of the image forming apparatus main body 11.

  The image forming unit 14 includes image forming units 22Y, 22M, 22C, and 22K (hereinafter referred to as 22Y to 22K) that form toner images of colors of yellow (Y), magenta (M), cyan (C), and black (K). And a transfer unit 70 having an intermediate transfer belt 24 as an example of an intermediate transfer body to which toner images formed by the image forming units 22Y to 22K are transferred, and a toner image transferred to the intermediate transfer belt 24 as an intermediate And a second transfer roll 28 for transferring from the transfer belt 24 to the recording medium P. The image forming unit 14 is not limited to the above-described configuration, and may be another configuration as long as it forms an image on the recording medium P.

  The image forming units 22Y to 22K are arranged side by side in the image forming apparatus main body 11 while being inclined with respect to the horizontal direction. Each of the image forming units 22Y to 22K includes a photoreceptor 32 that rotates in one direction (for example, the clockwise direction in FIG. 1). Since the image forming units 22Y to 22K are configured in the same manner, the reference numerals of the respective parts of the image forming units 22M, 22C, and 22K are omitted in FIG.

  Around each photoconductor 32, a charging roll 23 as a charging device for charging the photoconductor 32 in order from the upstream side in the rotation direction of the photoconductor 32, and a photoconductor 32 charged by the charge roll 23, which will be described later. Is provided with a developing device 38 that develops the electrostatic latent image formed on the photoconductor 32 by exposure to form a toner image, and a removal device 60 that removes residual toner remaining on the photoconductor 32. Yes.

  An exposure device 36 that exposes the photoreceptor 32 charged by the charging roll 23 to form an electrostatic latent image on the photoreceptor 32 is provided obliquely below the image forming units 22Y to 22K. The exposure device 36 is configured to form an electrostatic latent image based on the image signal sent from the control unit 20. Examples of the image signal sent from the control unit 20 include an image signal acquired by the control unit 20 from an external device.

  The developing device 38 includes a developer supply body 38A that supplies the developer to the photoconductor 32, and a plurality of transport members 38B that transport the developer applied to the developer supply body 38A while stirring.

  The transfer unit 70 includes a plurality (four) of first transfer rolls 26 that transfer the toner images formed by the image forming units 22Y to 22K to the intermediate transfer belt 24. The first transfer rolls 26 face the photoconductor 32 with the intermediate transfer belt 24 interposed therebetween. The first transfer roll 26 transfers the toner image formed on the photoconductor 32 to the intermediate transfer belt 24 by applying a transfer voltage (bias). A space between the first transfer roll 26 and the photoconductor 32 is a first transfer position T1 at which the toner image formed on the photoconductor 32 is transferred to the intermediate transfer belt 24.

  The second transfer roll 28 is opposed to a later-described counter roll 42 with the intermediate transfer belt 24 interposed therebetween. The second transfer roll 28 transfers the toner image transferred to the intermediate transfer belt 24 to the recording medium P by applying a transfer voltage (bias). A space between the second transfer roll 28 and the opposing roll 42 is a second transfer position T2 at which the toner image transferred to the intermediate transfer belt 24 is transferred to the recording medium P.

  The transport unit 16 is disposed along the transport path 48 and is transported along a transport roll 48 for transporting the recording medium P stored in the storage section 12, a transport path 48 for transporting the recording medium P transported to the transport roll 46. And a plurality of transport rolls 50 for transporting the recording medium P sent out by the roll 46 to the second transfer position T2.

  A fixing device 40 that fixes the toner image formed on the recording medium P by the image forming unit 14 to the recording medium P is provided on the downstream side in the transport direction from the second transfer position T2. A discharge roll 52 that discharges the recording medium P on which the toner image is fixed to the discharge unit 18 is provided downstream of the fixing device 40 in the transport direction.

  Further, the reverse conveyance path 37 for reversing the recording medium P on which the toner image is fixed on one side and sending it back to the second transfer position T2 is opposite to the intermediate transfer belt 24 with respect to the conveyance path 48 (FIG. 1). On the right side). When images are formed on both sides of the recording medium P, the recording medium P having a toner image fixed on one side is switched back by the discharge roll 52 and guided to the reverse conveyance path 37 and sent to the second transfer position T2. It is supposed to be returned.

  As shown in FIG. 2, a cover 150 serving as an opening / closing portion that opens and closes an outlet 153 for taking out the transfer unit 70 from the image forming apparatus main body 11 is provided on the upper portion of the image forming apparatus main body 11. . Specifically, the cover 150 is configured to open the outlet 153 by rotating around a rotating shaft 152 provided at one end thereof. Further, the cover 150 constitutes a part of the discharge portion 18 in a state where the outlet 153 is closed.

  The transfer unit 70 is provided in the image forming apparatus main body 11 so as to be removable in an orthogonal direction (upward left direction in FIG. 1) orthogonal to the rotation axis direction of the photoconductor 32. The transfer unit 70 is detachably attached to the image forming apparatus main body 11 in a state where the cover 150 opens the outlet 153 and the intermediate transfer belt 24 is separated from the photoconductor 32. A specific configuration of the transfer unit 70 will be described later.

(Image forming operation)
Next, an image forming operation for forming an image on the recording medium P in the image forming apparatus 10 according to the present embodiment will be described.

  In the image forming apparatus 10 according to the present embodiment, the recording medium P sent out from the storage unit 12 by the sending roll 46 is sent to the second transfer position T2 by the plurality of conveying rolls 50.

  On the other hand, in the image forming units 22 </ b> Y to 22 </ b> K, the photosensitive member 32 charged by the charging roll 23 is exposed by the exposure device 36 to form an electrostatic latent image on the photosensitive member 32. The electrostatic latent image is developed by the developing device 38 to form a toner image on the photoreceptor 32. The toner images of the respective colors formed by the image forming units 22Y to 22K are superimposed on the intermediate transfer belt 24 at each first transfer position T1, thereby forming a color image. Then, the color image formed on the intermediate transfer belt 24 is transferred to the recording medium P at the second transfer position T2.

  The recording medium P on which the toner image is transferred is conveyed to the fixing device 40, and the transferred toner image is fixed by the fixing device 40. When an image is formed only on one side of the recording medium P, the recording medium P is discharged to the discharge unit 18 by the discharge roll 52 after the toner image is fixed. When forming an image on both sides of the recording medium P, after the image is formed on one side, the recording medium P is switched back by the discharge roll 52, reversed, and sent to the reverse conveyance path 37. Further, the sheet is fed again from the reverse conveyance path 37 to the second transfer position T2, and an image is formed on the opposite surface where no image is recorded in the same manner as described above, and an image is formed on both surfaces of the recording medium P. Is discharged to the discharge unit 18. As described above, a series of image forming operations are performed.

(Specific configuration of transfer unit 70)
Next, a specific configuration of the transfer unit 70 will be described.

  As shown in FIG. 3, the transfer unit 70 includes a transfer unit body 71 as an example of a detachable body that is detachably attached to the image forming apparatus body 11, the intermediate transfer belt 24, and the 4 described above. Two first transfer rolls 26.

  The transfer unit main body 71 has a pair of frame members 72 that constitute the skeleton of the transfer unit 70. The pair of frame members 72 are disposed at both ends of the four first transfer rolls 26 in the rotation axis direction, and have a length along the direction in which the transfer unit main body 71 is taken out (arrow C direction).

  The outer surfaces of the pair of frame members 72 are guided portions guided by guide grooves (not shown) as guide portions of the image forming apparatus main body 11 when the transfer unit 70 is attached to and detached from the image forming apparatus main body 11. A plurality of protrusions 73 are formed.

  Further, a removal device 61 that removes residual toner remaining on the intermediate transfer belt 24 is provided at one end in the longitudinal direction of the pair of frame members 72 (end on the upper left side in FIG. 3). Further, at one end in the longitudinal direction, a pair of gripping portions 70 </ b> A are provided for an operator to grip when the transfer unit 70 is attached to and detached from the image forming apparatus main body 11.

  The intermediate transfer belt 24 is provided between the pair of frame members 72. As shown in FIG. 1, on the inner peripheral side of the intermediate transfer belt 24, the intermediate transfer belt 24 is wound and driven to rotate, and the intermediate transfer belt 24 is wound and tension is applied to the intermediate transfer belt 24. A tension applying roll 45 as an example of a tension applying member to be applied and an opposing roll 42 wound around the intermediate transfer belt 24 and facing the second transfer roll 28 with the intermediate transfer belt 24 interposed therebetween are provided. Specifically, the tension applying roll 45 is wound around the inner peripheral surface of the intermediate transfer belt 24 downstream of the first transfer position T1 in the transport direction and upstream of the second transfer position T2.

  The drive roll 43 is rotatably supported by the pair of frame members 72. When the drive roll 43 is driven to rotate, the intermediate transfer belt 24 rotates (circulates) in the counterclockwise direction in FIG. The intermediate transfer belt 24 conveys the image transferred at each first transfer position T1 to the second transfer position T2 by the rotation, and transfers the image to the recording medium at the second transfer position. The opposing roll 42 is rotatably supported by a pair of frame members 72 and is rotated by following the rotating intermediate transfer belt 24.

  Further, both ends of the rotating shaft 45A (including the supporting shaft that supports the rotating shaft) of the tension applying roll 45 are formed in an L shape as viewed in the axial direction of the rotating shaft 45A, as shown in FIG. The holding member 80 is rotatably supported at one end. Further, a shaft portion 84 is provided at a corner portion of the holding member 80, and the holding member 80 is rotatably supported by the frame member 72 by the shaft portion 84. That is, the holding member 80 rotates around the shaft portion 84, and the tension applying roll 45 can move in an arc shape around the shaft portion 84.

  Further, a distal end portion of a compression coil spring 86 as an urging member is attached to the other end portion (end portion extending obliquely upward to the right) of the holding member 80, and the proximal end portion of the compression coil spring 86 is The mounting member 78 is fixed to the frame member 72. The holding member 80 is rotated about the shaft portion 84 by the urging force (pushing force) of the compression coil spring 86, and the tension applying roll 45 moves the inner peripheral surface of the intermediate transfer belt 24 on the outer peripheral side (arrow). (B direction). As a result, a predetermined range of tension is applied to the intermediate transfer belt 24.

  In the present embodiment, the portion 24A between the opposing roll 42 and the tension applying roll 45 in the intermediate transfer belt 24 is (outer peripheral surface) and hits the tip of the recording medium P conveyed to the second transfer position T2, and the recording medium. It functions as a guide surface for guiding P, and the tension applying roll 45 moves in the direction of arrow B and the opposite direction so that the orientation of the guide surface is maintained within a predetermined range. ing.

  The four first transfer rolls 26 arranged on the inner periphery of the intermediate transfer belt 24 are in contact with the inner peripheral surface of the intermediate transfer belt 24 (see FIG. 1), and the inner peripheral surface of the intermediate transfer belt 24. The frame member 72 is supported by a pair of frame members 72 so as to be movable between a separation position (see FIG. 2) and a separation position.

  As shown in FIG. 3, the pair of frame members 72 include urging members (not shown) that urge the four first transfer rolls 26 toward the contact position with respect to the inner peripheral surface of the intermediate transfer belt 24. A moving mechanism 79 is provided for moving the four first transfer rolls 26 to a position separated from the inner peripheral surface of the intermediate transfer belt 24 against the urging force of the urging member.

  In the present embodiment, the four first transfer rolls 26 are separated from the intermediate transfer belt 24, thereby separating the intermediate transfer belt 24 from the photosensitive member 32 (see FIG. 2), and the four first transfer rolls 26 are intermediately transferred. By contacting the belt 24, the intermediate transfer belt 24 is brought into contact with the photosensitive member 32 (see FIG. 1). The separating operation for separating the intermediate transfer belt 24 from the photoreceptor 32 is performed, for example, when the transfer unit 70 is attached to or detached from the image forming apparatus main body 11.

(Grounding mechanism 91)
Next, the grounding mechanism 91 for grounding the tension applying roll 45 to the frame (reference potential point) of the image forming apparatus main body 11 will be described. 4 and 5 are schematic views showing the configuration of the grounding mechanism 91. FIG.

  As shown in FIGS. 4 and 5, the grounding mechanism 91 includes a contact member 90 that contacts the tension applying roll 45, and a support member 94 that supports the contact member 90.

  The contact member 90 is disposed on the pressing direction side (arrow B direction side) of the tension applying roll 45 with respect to the intermediate transfer belt 24. The contact member 90 includes a pair of contact portions 92 that are disposed on both ends in the axial direction of the tension applying roll 45 and contact the rotation shaft 45A of the tension applying roll 45, and a connecting portion 93 that connects the pair of contact portions 92. Yes. A groove 92A into which the rotation shaft 45A of the tension applying roll 45 is fitted is formed at one end of the pair of contact portions 92 (end on the upper right side in FIG. 4). Specifically, the rotating shaft 45A of the tension applying roll 45 comes into contact with the bottom wall of the groove portion 92A at two points when viewed in the axial direction. The groove 92A opens in the direction in which the transfer unit 70 is removed (direction of arrow C). Further, in the pair of contact portions 92, an inclined portion 92B is formed on the removal direction (arrow C direction) side of the transfer unit 70 with respect to the groove portion 92A.

  Specifically, the connecting portion 93 connects the other end portions of the pair of contact portions 92 (the end portion on the diagonally lower left side in FIG. 4), and has a length along the axial direction of the tension applying roll 45. ing. At both ends in the longitudinal direction of the connecting portion 93, columnar protruding portions 93A that protrude outward in the length direction are provided. The protruding portion 93A is inserted into a long hole 94C described later.

  A detection sensor 99 as an example of a detection unit that detects the density of each color toner image transferred to the intermediate transfer belt 24 is fixed to the connection unit 93 so as to face the intermediate transfer belt 24. Yes. That is, the contact member 90 functions as an example of a holding member that holds the detection sensor 99.

  The support member 94 is provided on the side opposite to the tension applying roll 45 with respect to the contact member 90 (an end portion on the diagonally lower left side in FIG. 4), and a pair of the support members 94 disposed so as to sandwich the pair of contact portions 92 from the outside. The support part 94A and a connecting part 94B for connecting the pair of support parts 94A are provided.

  A long hole 94 </ b> C having a length along the radial direction of the tension applying roll 45 is formed on one end side (upper right side in FIG. 4) of the support portion 94 </ b> A. A protrusion 93A of the contact member 90 is inserted into the long hole 94C, and the protrusion 93A can move and rotate within the long hole 94C. That is, the contact member 90 can be moved by the support member 94 along the length direction of the long hole 94 </ b> C (the radial direction of the tension applying roll 45) and around the rotation axis along the axial direction of the tension applying roll 45. It is supported.

  Specifically, the connecting portion 94B connects the other end portions of the pair of support portions 94A (the end portion on the diagonally lower left side in FIG. 4), and has a length along the axial direction of the tension applying roll 45. ing. The connecting portion 94B is a fixing member (not shown) and is fixed to the frame of the image forming apparatus main body 11.

  Between the connecting portion 93 of the contact member 90 and the connecting portion 94B of the support member 94, the contact member 90 is connected to the groove portion 92A formed in the contact portion 92 so that the rotating shaft 45A is fitted to one end in the longitudinal direction of the long hole 94C. Two compression coil springs 96 are provided side by side in the longitudinal direction of the connecting portion 94B as an example of an urging member that urges toward the side (the diagonally upper right side in FIG. 4). That is, the contact member 90 is urged by the compression coil spring 96 toward the tension applying roll 45 in the direction opposite to the pressing direction of the tension applying roll 45 (arrow B direction).

  In the grounding mechanism 91, even if the tension applying roll 45 is rotated about one or the other about the shaft portion 84 by changing the length of the intermediate transfer belt 24 by changing the environment such as humidity and room temperature, the compression coil The protrusion 93A of the contact member 90 biased by the spring 96 moves and rotates in the long hole 94C, so that the state in which the groove 92A is fitted to the rotation shaft 45A of the tension applying roll 45 is maintained. It has become.

(Operation of this embodiment)
Next, the operation of this embodiment will be described.

  In this embodiment, as shown in FIG. 2, when the cover 150 is rotated to open the outlet 153 and the transfer unit 70 is taken out from the image forming apparatus main body 11 through the outlet 153 in the diagonally upper left direction in FIG. 2. As shown in FIG. 6, the contact member 90 moves to the upper right in FIG. 6 by the biasing force of the compression coil spring 96. The protrusion 93A of the contact member 90 abuts against one end in the longitudinal direction of the long hole 94C, and the movement of the contact member 90 is restricted.

  When the removed transfer unit 70 is attached to the image forming apparatus main body 11, the rotating shaft 45A of the tension applying roll 45 hits the inclined portion 92B and pushes down the contact member 90, as shown in FIG. Fits into the groove 92A. As a result, the tension applying roll 45, the contact member 90, the support member 94 and the frame (reference potential point) of the image forming apparatus main body 11 are brought into conduction, and the charge on the inner peripheral surface of the intermediate transfer belt 24 is transferred to the tension applying roll 45. Through the contact member 90 and the support member 94, the contact member 90 and the support member 94 escape to the frame of the image forming apparatus main body 11. In this manner, the inner peripheral surface of the intermediate transfer belt 24 is neutralized between the first transfer position T1 and the second transfer position T2.

  In the present embodiment, since the image forming apparatus main body 11 is provided with the contact member 90 that is electrically connected to the tension applying roll 45, the member that is electrically connected to the tension applying roll 45 is provided in the transfer unit 70 and is grounded in the transfer unit 70. Compared with the case where a path is provided, the configuration of the transfer unit 70 that is attached to and detached from the image forming apparatus main body 11 can be simplified and downsized. That is, in the configuration in which the tension applying roll 45 is displaced, when a member that is electrically connected to the tension applying roll 45 is provided in the transfer unit 70 and a ground path is provided in the transfer unit 70, the ground path becomes complicated, and the transfer unit 70 is complicated. The configuration becomes complicated and large.

  In this embodiment, since the contact member 90 is biased in the direction opposite to the direction in which the tension applying roll 45 is pushed, even if the dimensions of the components (such as the compression coil spring 86) of the transfer unit 70 vary, The state where the groove 92A is fitted to the rotation shaft 45A of the tension applying roll 45 is maintained. Thereby, poor contact between the contact member 90 and the tension applying roll 45 is suppressed.

  Further, in this embodiment, even when the environment such as humidity and room temperature is changed and the length of the intermediate transfer belt 24 is changed, even when the tension applying roll 45 is rotated about one or the other about the shaft portion 84, The protrusion 93A of the contact member 90 urged toward the longitudinal direction one end side of the long hole 94C by the compression coil spring 96 moves and rotates in the long hole 94C, so that the rotation shaft 45A of the tension applying roll 45 is rotated. The state in which the groove 92A is fitted is maintained. Thereby, poor contact between the contact member 90 and the tension applying roll 45 is suppressed.

  Further, since the state where the groove 92A is fitted to the rotation shaft 45A of the tension applying roll 45 is maintained, the distance between the detection sensor 99 and the intermediate transfer belt 24 is maintained at a predetermined value. Thereby, variation in the detection result of the detection sensor 99 is suppressed.

  In the present embodiment, since the contact member 90 also serves as a holding member for the detection sensor 99, the number of parts is reduced as compared with the case where the detection sensor 99 is held using a dedicated part.

(Modification)
In this embodiment, the intermediate transfer belt 24 is supported by the three rolls of the drive roll 43, the tension applying roll 45, and the opposing roll 42, but may be configured to be supported by four or more rolls.

  Further, in this embodiment, the tension applying roll 45 presses the intermediate transfer belt 24 in the direction of arrow B in FIG. 4, but the pressing direction of the tension applying roll 45 is limited to the case in the direction of arrow B in FIG. is not. For example, as shown in FIG. 8, the tension applying roll 45 moves the inner peripheral surface of the intermediate transfer belt 24 along the mounting direction of the transfer unit 70 (arrow) by the biasing force (pushing force) of the compression coil spring 186. It may be configured to push in the (D direction). Note that one end of the compression coil spring 186 is fixed to the rotation shaft 45 </ b> A of the tension applying roll 45, and the other end is attached to an attachment member 178 fixed to the frame member 72.

  In this configuration, the grounding mechanism 91 is disposed on the pushing direction side (arrow D direction side) of the tension applying roll 45 with respect to the intermediate transfer belt 24. Further, the groove portion 92 </ b> A of the contact portion 92 is open in the direction in which the transfer unit 70 is removed (direction of arrow C). Further, the contact member 90 is urged by the compression coil spring 96 toward the tension applying roll 45 in a direction (arrow C direction) opposite to the direction in which the tension applying roll 45 is pushed (arrow D direction).

  The present invention is not limited to the above embodiment, and various modifications, changes, and improvements can be made. For example, the modification examples described above may be appropriately combined.

10 Image forming apparatus 24 Intermediate transfer belt (an example of an intermediate transfer member)
45 Tension imparting roll (an example of a tension imparting member)
71 Transfer unit body (example of removable body)
90 Contact member 99 Detection sensor P Recording medium T1 Transfer position T2 Transfer position

Claims (3)

An annular intermediate transfer body that conveys the image transferred at the first transfer position to the second transfer position by circulation, and transfers the image to a recording medium at the second transfer position;
Wrapped around the inner peripheral surface of the intermediate transfer member downstream of the first transfer position in the transport direction and upstream of the second transfer position in the transport direction, and presses the intermediate transfer member toward the outer peripheral side to tension the intermediate transfer member A tension applying member for applying
A removable body provided with the intermediate transfer body and the tension applying member, and attached to and detached from the apparatus main body integrally with the intermediate transfer body and the tension applying member;
In the mounting state of the detachable body with respect to the apparatus main body, the tension applying member is provided on the apparatus main body so as to come into contact with the tension applying member on the pressing direction side with respect to the intermediate transfer body. A contact member for releasing the charge on the inner peripheral surface of the intermediate transfer member;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the contact member is urged toward the tension applying member in a direction opposite to a pushing direction of the tension applying member.   The image forming apparatus according to claim 1, wherein the contact member also serves as a holding member that holds a detection unit that detects an image density of the intermediate transfer member.

Images