JP2013109022A - Drive transmission device, and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which: a driving member and a drive transmission member collides to generate collision noise.SOLUTION: When a drive transmission member moves from a state of being engaged with a driving member in a direction in which the engagement of the drive transmission member and the driving member is released by a contact member contacting the drive transmission member, a direction in which urging means urges the drive transmission member changes from a direction in which the drive transmission member is engaged with the driving member to a direction in which the engagement of the drive transmission member and the driving member is released.

Description

  The present invention relates to a drive transmission device capable of releasing transmission of a drive force from a drive member rotated by a drive source to a driven member, and an image forming apparatus using the drive transmission device.

  2. Description of the Related Art Conventionally, in image forming apparatuses such as copying machines, printers, and facsimiles, a drive transmission device that performs an intermittent rotation operation is used for a contact-separation mechanism of a transfer roller, a sheet pickup mechanism of a sheet feeding unit, and the like. In such a drive transmission device, it is common to use an electromagnetic clutch, a dedicated motor, etc. in order to perform an intermittent rotation operation. There exists a structure shown in patent document 1.

  FIG. 10 is a simplified view of a conventional drive transmission device described in Patent Document 1. In FIG. This configuration will be described. A drive gear (drive member) 22 that is rotationally driven in the direction of arrow A by a drive source (not shown) and a driven gear 23 that can rotate coaxially with the drive gear 22 are provided. The driven gear 23 holds a drive transmission member 24 that is rotatable with respect to the driven gear (driven member) 23 and is movable between a position where it is engaged with the drive gear 22 and a position where the engagement is released. Yes.

  As shown in FIG. 10A, when the engaging portion 24 a of the drive transmission member 24 is engaged with the drive gear 22, the driving force is transmitted from the drive gear 22 to the driven gear 23 via the drive transmission member 24. Communicated. For this reason, the driven gear 23 and the drive transmission member 24 rotate integrally with the drive gear 22 in the arrow A direction.

  When releasing the transmission of the driving force to the driven gear 23, as shown in FIG. 10B, the contact member 17 is moved to a position where it contacts the drive transmission member 24, and the drive transmission member 24 is locked. Thus, the engagement between the drive transmission member 24 and the drive gear 22 is released. By doing so, the transmission of the driving force from the driving gear 22 to the driven gear 23 is released.

JP-A-3-158328

  In Patent Document 1, the drive transmission member 24 is urged by a spring 25 in a direction to mesh with the drive gear 22 so that the engagement portion 24a of the drive transmission member 24 is reliably engaged with the drive gear 22. Therefore, in order to cancel the transmission of the driving force to the driven gear 23, the driving transmission member 24 is moved against the urging force of the spring 25 when the abutting member 17 abuts against the driving transmission member 24. It is necessary to release (retract) from 22 and release the engagement.

  Here, in the configuration of Patent Document 1, the driving force is not transmitted from the driving gear 22 to the driven gear 23 at the moment when the engagement of the driving gear 22 with the tip of the engaging portion 24a of the driving transmission member 24 is disengaged. The rotation of the driven gear 23 is immediately stopped by the load applied to the gear 23. For this reason, when the rotation of the driven gear 23 stops, there is a possibility that the tip of the engaging portion 24a of the drive transmission member 24 cannot move to a position away (retracted) from the drive gear 22 with a sufficient distance.

  On the other hand, normally, there is a backlash or other backlash between the driven gear 23 and a member on the downstream side in the drive transmission direction of the driven gear 23, and the driven gear 23 is in a state where no driving force is transmitted from the drive gear 22. Will be able to rotate backwards by backlash. For this reason, when the driven gear 23 rotates in the reverse direction due to vibration or the like in the apparatus main body, the tip of the engaging portion 24a of the drive transmission member 24 collides with the driving gear 22 that continues to rotate by the driving source, and the collision sound Etc. may occur.

  Therefore, in view of the above problems, the present invention provides a drive transmission device that uses a driven member that holds a drive transmission member that can be engaged with the drive member. The purpose is to further suppress this.

  The present invention comprises a driving member that rotates by a driving force from a driving source, a driven member that rotates coaxially with the driving member in response to the driving force from the driving member, and is held movably with respect to the driven member, A drive transmission member that engages the drive member; an urging means that urges the drive transmission member; and a contact that abuts the drive transmission member to release the engagement between the drive transmission member and the drive member. A contact member, and when the drive transmission member is engaged with the drive member, a drive force is transmitted from the drive member to the driven member via the drive transmission member, and the drive transmission member In the drive transmission device in which transmission of the driving force from the drive member to the driven member is released when the engagement with the drive member is released, the drive transmission member is engaged with the drive member From said contact member When the drive transmission member contacts and moves in a direction in which the engagement with the drive member is released, the direction in which the urging means urges the drive transmission member is related to the drive transmission member engaged with the drive member. The direction is changed from the direction in which the engagement between the drive transmission member and the drive member is released.

  According to the present invention, in the drive transmission device using the driven member that holds the drive transmission member that can be engaged with the drive member, the drive transmission member can be reliably retracted from the drive member, and the occurrence of a collision sound or the like can be further suppressed. it can.

1 is a schematic sectional view of an image forming apparatus. The perspective view of a drive transmission device. (A) The side view which looked at the drive transmission apparatus from the direction orthogonal to the axis | shaft of a rotation center. (B) The figure which shows the state which decomposed | disassembled the input gear and the output gear in the position of AA and BB of (a), and looked at each of the input gear side and the output gear side from the inside. (A) The figure which looked at the drive transmission lever from the input gear side toward the output gear side in the axial direction. (B) The figure which looked at the drive transmission lever from the input gear side toward the output gear side in the axial direction. (A) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (B) The perspective view of drive transmission lever and contact member vicinity. (A) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (B) The perspective view of drive transmission lever and contact member vicinity. (A) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (B) The perspective view of drive transmission lever and contact member vicinity. (C) The enlarged view which looked at the contact member from the axial direction of the rotation center. (A) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (B) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (A) The figure which looked at the drive transmission device toward the output gear side from the input gear side in the axial direction of the rotation center. (B) The perspective view of drive transmission lever and contact member vicinity. (C) The enlarged view which looked at the contact member from the axial direction of the rotation center. (A) The figure which simplifies and shows the conventional drive transmission device. (B) The figure which simplifies and shows the conventional drive transmission device.

<First Embodiment>
A first embodiment of the present invention will be described. In the present embodiment, a drive transmission device mounted on an electrophotographic image forming apparatus will be described. The image forming apparatus will be described first before describing the drive transmission device.

[Image forming apparatus]
FIG. 1 is a schematic sectional view of the image forming apparatus. This image forming apparatus is a tandem type electrophotographic color laser printer using an intermediate transfer belt (intermediate transfer member).

  The image forming apparatus 600 includes four image forming units Y, M, C, and K that form toner images of yellow, magenta, cyan, and black, and these image forming units Y, M, C, and K are images. In the forming apparatus main body 600, they are arranged in parallel from left to right.

  Each of the image forming units Y, M, C, and K is an image forming unit of an electrophotographic image forming system, and each of the image forming units except for forming a different color toner image on the photosensitive drum of each image forming unit. The configuration of the parts is the same. Each image forming unit has a photosensitive drum 1 (1Y, 1M, 1C, 1K). Further, in each image forming unit, a charging roller 2 (2Y, 2M, 2C, 2K) and a developing roller 3 (3Y, 3M, 3C, 3K) are provided around the photosensitive drum 1 as process means acting on the photosensitive drum 1. And a transfer roller 7 (7Y, 7M, 7C, 7K) and a cleaning blade 8 (8Y, 8M, 8C, 8K). Further, a laser scanner 4 for irradiating each photosensitive drum 1 with laser light corresponding to image information is provided below each photosensitive drum 1.

  Next, image formation in each image forming unit will be described. Each photosensitive drum 1 is driven to rotate clockwise in FIG. In this state, the photosensitive drum 1 is charged by the charging roller 2 and irradiated with laser light from the laser scanner 4 to form a latent image. A toner image is formed on the surface of the photosensitive drum 1 by attaching toner that adheres to the developing roller 3 to the latent image. A yellow toner image, which is a color separation component color of the full-color image, is formed on the surface of the photosensitive drum 1Y of the image forming unit Y, and a magenta toner image is formed on the surface of the photosensitive drum 1M of the image forming unit M. Further, a cyan toner image is formed on the surface of the photosensitive drum 1C of the image forming unit C, and a black toner image is formed on the surface of the photosensitive drum 1C of the image forming unit C.

  On the other hand, an intermediate transfer belt 601 to which a toner image is transferred from each photosensitive drum 1 is disposed above the image forming portions Y, M, C, and K. The intermediate transfer belt 601 has a winding roller 5 disposed on the image forming unit Y side, a winding roller 6 disposed on the image forming unit K side, and a secondary transfer facing member disposed above the hanging roller 6. The roller 602T is stretched between the three parallel-arranged rollers. The rolling roller 6 is a roller for driving the intermediate transfer belt 601 in the direction of arrow B (counterclockwise) so that the speed of the surface of the intermediate transfer belt 601 is substantially the same as the speed of the surface of each photosensitive drum 1. Rotation is driven by a drive source (not shown).

  A primary transfer roller 7 is disposed between the winding rollers 5 and 6 so as to face the photosensitive drums 1 of the image forming portions Y, M, C, and K with the intermediate transfer belt 61 interposed therebetween. A nip portion T1 is formed. A primary transfer bias is applied at the primary transfer nip to transfer the toner image on each photosensitive drum 1 onto the intermediate transfer belt 601.

  A secondary transfer roller 602 is disposed downstream of the primary transfer nip T1 in the rotation direction of the intermediate transfer belt 601 so as to face the secondary transfer counter roller 602T with the intermediate transfer belt 61 interposed therebetween. The secondary transfer roller 602 presses the secondary transfer counter roller 602T via the intermediate transfer belt 601, and the intermediate transfer belt 601 and the secondary transfer roller 602 form a secondary transfer nip portion T2. The toner image on the intermediate transfer belt 601 is transferred onto a sheet conveyed to the secondary transfer nip T2 by applying a secondary transfer bias at the secondary transfer nip T2.

  An intermediate transfer belt cleaner 603 is disposed at a position facing the winding roller 5 downstream of the intermediate transfer belt 601 in the rotation direction of the secondary transfer nip T2. The intermediate transfer belt cleaner 603 brings the cleaning blade into contact with the outer surface of the intermediate transfer belt 601 and scrapes off the remaining toner that is not transferred at the secondary transfer nip portion T2.

  Reference numeral 604 denotes a fixing device including a pressure roller pair of a fixing roller (heating roller) 604a and a pressure roller 604b.

  Next, a process for forming a four-color toner image on the sheet S will be described. Reference numeral 605 denotes a control board as control means for controlling the image forming apparatus, and controls an image forming operation of the image forming apparatus. The control substrate 605 forms yellow, magenta, cyan, and black toner images on the photosensitive drums 1 of the image forming units Y, M, C, and K based on the print start signal. Each toner image is sequentially superimposed and transferred onto the intermediate transfer belt 601 at the primary transfer nip T1, forming four color toner images on the intermediate transfer belt 601, and four-color toner images onto the secondary transfer nip T2. Move on.

  On the other hand, one sheet (recording material) S stacked and housed in the sheet feeding cassette 9 is separated and fed by the rotational driving of the sheet feeding roller 10 and conveyed to the registration roller pair 11. The registration roller pair 11 introduces the sheet S into the secondary transfer nip T2 in accordance with the arrival of the four color toner images on the intermediate transfer belt 601 at the secondary transfer nip T2. Then, the four color toner images on the intermediate transfer belt 601 are transferred onto the sheet S by the secondary transfer bias. The sheet S exiting the secondary transfer nip portion T2 is conveyed to the fixing device 604 and heated and pressed to fix the unfixed toner image on the sheet S. In this manner, four color toner images are formed on the sheet S.

  Incidentally, in the image forming apparatus 600, there is a possibility that the photosensitive drums 1Y, 1M, and 1C of the image forming units Y, M, and C are rubbed against the intermediate transfer belt 601 and worn out during monochromatic image formation (monochrome printing). Therefore, in order to prevent this, a primary transfer roller contact / separation mechanism (not shown) that enables the primary transfer rollers 7Y, 7M, and 7C to be separated from the intermediate transfer belt 601 is provided. The primary transfer roller contact / separation mechanism includes a cam, and is configured to switch between the contact state and the separation state of the primary transfer roller 7 by changing the rotation phase of the cam. The drive transmission device of this embodiment is used in a part of a gear train that intermittently transmits a driving force to the cam and rotates the cam by a predetermined angle at a predetermined timing.

[Drive transmission device]
FIG. 2 is a perspective view of the drive transmission device of the present embodiment. As in the first embodiment, this apparatus has an input gear (drive member) 101, an output gear (driven member) 102, and a solenoid SL. The input gear 101 is drivingly connected to a motor (drive source) (not shown) via a gear 103 and is rotated by a driving force from the motor. The output gear 102 is provided with a cam of a primary transfer roller contact / separation mechanism (not shown) for switching between the contact state and the separation state of the primary transfer roller 7 via the gear 104 and the drive output shaft 105. It is drivingly connected to a gear train to be driven. Both the input gear 101 and the output gear 102 rotate coaxially around the rotation center 106.

  A drive transmission claw and a drive transmission lever are arranged in a space between the input gear 101 and the output gear 102. Next, these arrangement relationships will be described. FIG. 3A is a side view of the drive transmission device viewed from a direction orthogonal to the axis of the rotation center (rotation axis) 106. FIG. 3B is an exploded view of the input gear 101 and the output gear 102 at positions AA and BB in FIG. 3A, and the input gear 101 side and the output gear 102 side are viewed from the inside. It is a figure which shows a state side by side. That is, the AA side (left side) of FIG. 3B is a view of the input gear 101 side, and the BB side (right side) is a view of the output gear 102 side. The solenoid SL is shown in the right figure.

  The input gear 101 is integrally formed with a drive transmission claw 201 around the rotation axis. A drive transmission lever (drive transmission member) 301 is held on the side surface of the output gear 102 as an engagement means that can be engaged with the drive transmission claw 201. The drive transmission lever 301 can be rotated around an axis 301 c different from the rotation center 106 of the output gear 102. The drive transmission lever 301 includes an engagement portion 301a that can be engaged with the drive transmission claw 201, and a contacted portion 301b that contacts the contact member 303 fixed to the solenoid SL.

  A spring 302 is provided between the tensioning part 102 b of the output gear 102 and the tensioning part 301 d of the drive transmission lever 301, and the drive transmission lever 301 is attached so that the urging direction changes depending on the attitude of the drive transmission lever 301. It is the composition which is dying. That is, the drive transmission lever 301 functions as a so-called toggle lever by the spring 302.

  Next, the configuration for biasing the drive transmission lever 301 by the spring 302 will be described in detail. 4A and 4B are views of the drive transmission lever 301 viewed from the input gear 101 side toward the output gear 102 side in the direction of the shaft 301c. Note that some of the input gear 101 and the output gear 102 are omitted.

  As shown in FIG. 4A, in the state where the stretched portion 301d of the drive transmission lever 301 is located on the right side of the straight line (neutral line) I connecting the stretched portion 102b and the shaft 301c, the spring 302 is stretched. The force pulling the portion 301d acts to rotate the drive transmission lever 301 in the F direction. That is, in this state, the drive transmission lever 301 is urged toward the F direction by the spring 302. On the other hand, in the state where the tension part 301d of the drive transmission lever 301 is located on the left side of the straight line (neutral line) I connecting the tension part 102b and the shaft 301c, the force with which the spring 302 pulls the tension part 301d is It acts to rotate the drive transmission lever 301 in the H direction. That is, in this state, the drive transmission lever 301 is urged toward the H direction by the spring 302.

  As described above, the biasing direction in which the spring 302 biases the drive transmission lever 301 is changed depending on which side of the neutral line I the tension portion 301d of the drive transmission lever 301 is located. Further, the drive transmission lever 301 biased in the H direction has an engaging portion 301 a engaged with the drive transmission claw 201 of the input gear 101. Further, the drive transmission lever 301 biased in the F direction rotates in the F direction so that the engaging portion 301a is separated from the drive transmission claw 201, and comes into contact with a stopper 102a provided in the output gear 102. Yes.

[Operation of drive transmission device]
Next, intermittent driving of the output gear 102 using the drive transmission device of the present embodiment will be described. 5 (a), 6 (a), 7 (a), 8 (a), 8 (b), and 9 (a) are the axial directions of the rotation center 106 from the input gear 101 side in each state. It is the figure which looked at the drive transmission device toward the output gear 102 side. For the sake of simplicity, the upper half of the input gear 101 is shown in a transparent state. FIGS. 5B, 6B, 7B, and 9B are perspective views of the vicinity of the drive transmission lever 301 and the contact member 303 in each state. 7C and 9C are enlarged views of the contact member 303 as viewed from the axial direction of the rotation center 106. FIG.

  FIGS. 5A and 5B show a standby state in which the driving force is not transmitted from the input gear 101 to the output gear 102 (the transmission of the driving force is released). In this state, the drive transmission lever 301 is urged in the F direction by the action of the spring 302 and abuts against the stopper 102a, and the engagement between the engagement portion 301a of the drive transmission lever 301 and the drive transmission claw 201 is released. Yes. The energization of the solenoid SL is released, and the contact member 303 fixed to the solenoid SL is in a state of being retracted in a direction away from the shaft 106, and the contacted part 301 b of the contact member 303 and the drive transmission lever 301 is removed. There is no contact.

  Next, when the solenoid SL is energized, as shown in FIGS. 6A and 6B, the contact member 303 moves in the J direction (direction approaching the shaft 106). The contact member 303 is formed with a pressing surface 303 a that presses the contacted portion 301 b of the drive transmission lever 301. Therefore, as the contact member 303 moves in the J direction, the pressing surface 303a presses the contacted portion 301b, so that the drive transmission lever 301 is resisted against the biasing force of the spring 302 in the F direction. Rotate in the H direction.

  When the contact member 303 further moves in the J direction, the state shown in FIGS. 7A, 7B, and 7C is obtained. As shown in FIGS. 7B and 7C, the contact member 303 has a notch 303b through which the contacted part 301b passes, and the pressing surface 303a extends to the inside of the notch 303b. Is provided. For this reason, the abutted portion 301b passes through the inside of the notch 303b and moves in the H direction while being abutted and pressed against the pressing surface 303a. Then, as described above, the tension portion 301d exceeds the neutral line I, and the direction in which the drive transmission lever 301 is urged by the spring 302 changes from the F direction to the H direction (see FIG. 4). Rotates in the H direction.

  Thus, the pressing surface 303a is configured to press the contacted portion 301b until at least the direction in which the drive transmission lever 301 is urged changes to the H direction. Further, the cutout portion 303b has a shape that does not hinder the movement of the abutted portion 301b in the H direction at this time.

  When the drive transmission lever 301 rotates in the H direction, as shown in FIG. 8A, the engagement portion 301a reaches an engagement position where the engagement portion 301a engages with the drive transmission claw 201, and the input rotates in the C direction. Engage with the drive transmission claw 201 of the gear 101. Therefore, the driving force is transmitted from the input gear 101 to the output gear 102 via the drive transmission lever 301, and the input gear 101, the drive transmission lever 301, and the output gear 102 are integrated as shown in FIG. 8B. Rotate in the C direction. The notch 303b does not prevent rotation of the abutted portion 301b in the C direction when the drive transmission lever 301 engages with the drive transmission claw 201 and the drive transmission lever 301 starts to rotate in the C direction. It has a shape.

  Further, when the output of the solenoid SL is released while the output gear 102 is rotating, the contact member 303 moves in the K direction (the direction opposite to the J direction), and the contacted portion 301b of the drive transmission lever 301 is engaged. Return to the lockable position.

  When the output gear 102 receives a driving force from the input gear 101 and makes one rotation, the state shown in FIGS. 9A, 9B, and 9C is obtained. As shown in FIGS. 9B and 9C, the contact member 303 is formed with a locking surface 303c for locking the contacted portion 301b. The locking surface 303c is integrated with the input gear 101. The abutted portion 301b that has rotated in the C direction abuts, and the abutted portion 301b of the drive transmission lever 301 is locked to the locking surface 303c.

  On the other hand, the engaging portion 301a is engaged with the drive transmission claw 201 and the driving force is transmitted from the input gear 101 to the output gear 102 via the drive transmission lever 301. Continues to rotate in the direction of arrow C. That is, the shaft 301c of the drive transmission lever 301 also rotates in the C direction.

  Therefore, the drive transmission lever 301 rotates in the F direction around the shaft 301c against the urging force of the spring 302 in a state where the contacted portion 301b is locked to the locking surface 303c of the contact member 303. To go. Then, as described above, the tension portion 301d exceeds the neutral line I, the direction in which the drive transmission lever 301 is urged by the spring 302 changes from the H direction to the F direction (see FIG. 4), and the drive transmission lever 301 is Rotate in the F direction. As a result, the engagement portion 301a of the drive transmission lever 301 is retracted (moved in the F direction) from the drive transmission claw 201, and the engagement between the engagement portion 301a and the drive transmission claw 201 is released. The drive transmission lever 301 stops rotating in the direction F by hitting the stopper 102a, and returns to the standby state (standby position) shown in FIG. For this reason, the driving force from the input gear 101 is not transmitted to the output gear 102 and the output gear 102 stops.

  Here, the drive transmission lever 301 is biased by the spring 302 after the contacted portion 301 b is locked to the contact member 303 and before the engagement between the engagement portion 301 a and the drive transmission claw 201 is released. The direction is changed from the H direction to the F direction. For this reason, the urging | biasing direction of the drive transmission lever by the spring 302 can be changed reliably by being latched by the contact member 303. FIG. Further, in a state where the drive transmission lever 301 is biased by the spring 302 and moves in the F direction, the engagement between the engagement portion 301a and the drive transmission claw 201 is released (the front end of the engagement portion 301a and the drive transmission claw). The tip of 201 is separated). Even after the engagement is released, the drive transmission lever 301 rotates in the F direction by the biasing force of the spring 302 and then abuts against the stopper 102a. For this reason, the engaging part 301a can move to the retracted position sufficiently away from the drive transmission claw 201.

  As described above, in this embodiment, in the configuration in which the driving force is transmitted from the input gear 101 to the output gear 102 via the drive transmission lever 301 held by the output gear 102, the drive transmission lever 301 is driven by the input gear 101. The biasing direction of the spring 302 that biases to engage with the transmission claw 201 can be changed. That is, when the contact member 303 locks the drive transmission lever 301 that is urged to rotate in the H direction and engages with the drive transmission claw 201, the urging direction of the drive transmission lever 301 is separated from the drive transmission claw 201 ( F direction). For this reason, the drive transmission lever 301 can be reliably retracted to a position where a sufficient distance from the drive transmission claw 201 is maintained by the biasing force of the spring 302. And by retreating reliably in this way, it is possible to solve mechanical problems such as reliable release of drive transmission and prevention of collision noise.

  In the above-described embodiment, the example in which the drive transmission device of the present invention is applied to the contact / separation mechanism of the primary transfer roller of the image forming apparatus has been described. However, the drive transmission device of the present invention is not limited to this. That is, the drive transmission device of the present invention drives the paper feed unit of the image forming apparatus, the contact / separation mechanism between the developing roller 3 and the photosensitive drum 1, switching of the drive of the toner replenishing unit, other drive transmission units, The present invention can be applied to a device having a drive transmission unit other than the image forming apparatus.

101 Input gear (drive member)
102 Output gear (driven member)
201 Drive transmission claw 301 Drive transmission lever (drive transmission member)
301a engaging part 301b contacted part 302 spring 303 abutting member

Claims (4)

A driving member that is rotated by a driving force from a driving source;
A driven member that receives a driving force from the driving member and rotates coaxially with the driving member;
A drive transmission member held movably with respect to the driven member and engaged with the drive member;
Biasing means for biasing the drive transmission member;
A contact member that contacts the drive transmission member in order to release the engagement between the drive transmission member and the drive member;
When the drive transmission member is engaged with the drive member, a drive force is transmitted from the drive member to the driven member via the drive transmission member, and the drive transmission member, the drive member, In the drive transmission device in which the transmission of the driving force from the driving member to the driven member is released when the engagement of the driving member is released,
When the drive transmission member is engaged with the drive member, the abutting member contacts and the drive transmission member moves in a direction in which the engagement with the drive member is released. The drive transmission characterized in that the direction in which the drive transmission member is biased changes from the direction in which the drive transmission member engages with the drive member to the direction in which the engagement between the drive transmission member and the drive member is released. apparatus. The contact member is movable;
From the state where the urging means urges the drive transmission member in a direction in which the engagement between the drive transmission member and the drive member is released, the contact member moves to press the drive transmission member. The direction in which the urging means urges the drive transmission member is changed to a direction in which the drive transmission member and the drive member are engaged by moving in a direction to engage with the drive member. The drive transmission device according to claim 1. 2. The drive transmission member moves in a direction away from the drive member by an urging force of the urging means when the engagement between the drive transmission member and the drive member is released. 3. The drive transmission device according to 2.   An image forming apparatus comprising the drive transmission device according to claim 1.

Images