JP6548777B2 - Drive transmission device and image forming apparatus - Google Patents

Description

  The present invention relates to a drive transmission device for transmitting a drive force to a unit detachable from an apparatus main body, and an image forming apparatus provided with the drive transmission device.

  In recent years, in image forming apparatuses such as electrophotographic printers and copiers, downsizing and improvement of operability have been desired.

  From the viewpoint of improving the operability of the image forming apparatus, a process cartridge system is adopted in which the photosensitive member, the charging unit, the developing unit, the cleaning unit, etc. are integrated into a cartridge, and this cartridge is detachable from the image forming apparatus main body. ing. This cartridge system further improves operability, and allows the user to easily maintain the process means such as development.

  Similarly to this, the intermediate transfer member and the like of the image forming apparatus main body also have a unit configuration, and can be detachably attached to the image forming apparatus main body to improve operability and maintainability.

  In addition, as a drive transmission device for stably and reliably transmitting the drive to these units detachably attachable to the image forming apparatus main body, a combination of a convex portion as shown in FIG. 26 and a corresponding concave portion is performed. Coupling is used.

  In Patent Document 1, the coupling on the apparatus body side is retracted from the coupling on the unit side by the operation of opening the cover in conjunction with the cover etc. which opens and closes the coupling pair, so the coupling pair is disconnected. An arrangement is disclosed that allows for the removal of the unit.

JP, 2005-157112, A

  However, in order to release and connect the coupling in conjunction with the opening and closing operation of the cover, it is necessary to provide a mechanism for releasing and connecting the coupling in addition to the opening and closing mechanism of the cover. This mechanism causes the deterioration of the opening / closing operability of the cover and the cost increase due to the complicated structure.

  For example, when a link mechanism is provided on the opening / closing cover in order to connect and release the coupling, the coupling is released and connected every time the cover is opened and closed, and the coupling release and connection which are not originally required Covers the load of the In this case, a load such as a resistance required to release and connect the coupling is added to the operating force for opening and closing the cover. In particular, in a color image forming apparatus in which four process cartridges are arranged, the load for releasing and connecting the coupling is also large, and the operability of opening and closing the cover is deteriorated.

  Also, the link mechanism is required to have high rigidity. Furthermore, since the link mechanism itself becomes large and the rigidity of the cover needs to be increased, the size of the apparatus is increased and the cost is increased.

An image forming apparatus according to the present invention for solving the above problems is provided in an apparatus main body, a unit detachably attachable to the apparatus main body, and the apparatus main body, and is a first coupling rotated by power from a drive source. And a second coupling provided in the unit and rotating in mesh with the first coupling, wherein the first coupling includes a first protrusion, and the second coupling The coupling comprises a second projection engaging with the first projection, at least one of the first coupling and the second coupling being with respect to the axis of rotation of the first coupling The second coupling is provided with an inclined inclined surface, and a force acting in the disengaging direction of the unit when the unit is pulled out from the device main body in a direction perpendicular to the rotation axis of the first coupling. Grayed has become a movable structure wherein the removing direction than the first coupling, the said second coupling from the state wherein the first coupling the second coupling is engaged in the process of moving the removing direction, the said other from contact with the inclined surface, the second coupling provided on at least one of the first coupling and the second coupling before Symbol It is characterized in that retraction is started in a direction parallel to the axis of rotation of the first coupling relative to the first coupling.

  According to the present invention, coupling / disengagement of the coupling, which is a drive transmission device from the device body to the detachable unit, is automatically performed along with the attachment / detachment action of the unit.

FIG. 1 is a cross-sectional view showing the main part of an image forming apparatus according to Embodiment 1 of the present invention. It is a perspective view which shows the attachment or detachment direction of the unit which concerns on Embodiment 1 of this invention. It is a top view which shows the attachment or detachment direction of the unit which concerns on Embodiment 1 of this invention. It is a perspective view which shows the principal part of the drive transmission apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the coupling which concerns on Embodiment 1 of this invention. FIG. 6 is a schematic view showing a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 1 of the present invention starts to be released. It is the schematic which shows the state in which the contact of the 1st engaging part and 2nd engaging part which concern on Embodiment 1 of this invention was cancelled | released. It is the schematic which shows the distance of the rotating shaft of the drive coupling which concerns on Embodiment 1 of this invention, and the rotating shaft of a to-be-driven coupling. It is a schematic perspective view which shows the transfer isolation | separation means based on Embodiment 1 of this invention (phase G). It is a schematic perspective view which shows the transfer isolation | separation means based on Embodiment 1 of this invention (phase H). It is a perspective view which shows the other coupling based on Embodiment 1 of this invention. It is a top view which shows the other phase of the coupling which concerns on Embodiment 1 of this invention. It is a perspective view which shows the coupling which concerns on Embodiment 2 of this invention. FIG. 13 is a schematic view showing a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 2 of the present invention starts to be released. It is the schematic which shows the state in which the contact of the 1st engaging part and 2nd engaging part which concern on Embodiment 2 of this invention was cancelled | released. It is the schematic which shows the distance of the rotating shaft of the drive coupling which concerns on Embodiment 2 of this invention, and the rotating shaft of a to-be-driven coupling. It is a perspective view which shows the other coupling based on Embodiment 2 of this invention. It is a perspective view which shows the coupling which concerns on Embodiment 3 of this invention. FIG. 14 is a schematic view showing a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 3 of the present invention starts to be released. It is the schematic which shows the state in which the contact of the 1st engaging part and 2nd engaging part which concern on Embodiment 3 of this invention was cancelled | released. It is the schematic which shows the distance of the rotating shaft of the drive coupling which concerns on Embodiment 3 of this invention, and the rotating shaft of a to-be-driven coupling. It is a perspective view which shows the other coupling based on Embodiment 3 of this invention. It is a perspective view which shows the coupling concerning Embodiment 4 of this invention. It is a perspective view which shows the attachment or detachment direction of a process cartridge. It is a top view which shows the attachment or detachment direction of a process cartridge. It is a perspective view which shows the principal part of the drive transmission device in background art.

Embodiment 1
The present embodiment will be described using an electrophotographic four-drum color image forming apparatus as an apparatus main body and an intermediate transfer unit as a detachable unit. Further, in the present embodiment, a drive transmission device is used to transmit the driving force for separating the primary transfer roller in the intermediate transfer unit from the corresponding photosensitive drum from the apparatus main body. The drive transmission device of the present embodiment has a first coupling and a second coupling that rotates in mesh with the first coupling.

  Hereinafter, an embodiment of the present invention will be described in the order of an image forming apparatus, an intermediate transfer unit, and a drive transmission device according to FIGS.

[Image forming apparatus]
First, the configuration of the device body 100 will be described.

  FIG. 1 is a cross-sectional view showing an example of an image forming apparatus according to the present invention.

(1) Toner Image Forming Process The toner image is formed by the photosensitive drum 1 as a photosensitive member, the charging roller 2 as a charging unit, the exposure unit 3, the developing unit 4 and the like. The apparatus main body 100 includes four photosensitive drums 1a, 1b, 1c and 1d. Around the respective photosensitive drums 1, charging rollers 2 (2a, 2b, 2c, 2d) for charging the surface of the photosensitive drums 1 uniformly according to the rotation direction are sequentially irradiated with a laser based on image information to There is an exposure unit 3 for forming an electrostatic latent image on 1. Further, the developing unit 4 (4a, 4b, 4c, 4d) for attaching toner to the electrostatic latent image on the photosensitive drum 1 and visualizing it as a toner image, and transferring the toner image on the photosensitive drum 1 to the intermediate transfer belt 12e. There are transfer means 12a, 12b, 12c and 12d. Further, cleaning means 8 (8a, 8b, 8c, 8d) for removing toner after transfer remaining on the surface of the photosensitive drum 1 after transfer are provided.

  The photosensitive drum 1, the charging roller 2, the developing unit 4, and the cleaning means 8 (8a, 8b, 8c, 8d) are respectively integrally formed into a cartridge to form a process cartridge 7 (7a, 7b, 7c, 7d). Each process cartridge is configured to be removable from the apparatus main body 100. These four process cartridges 7a, 7b, 7c, 7d have the same structure, but form different color images using toners of yellow (Y), magenta (M), cyan (C), and black (Bk). It differs in the point to do.

  The process cartridges 7a, 7b, 7c and 7d are constituted by developing units 4a, 4b, 4c and 4d and cleaning units 5a, 5b, 5c and 5d. Among them, the former developing units 4a, 4b, 4c and 4d have developing rollers 24a, 24b, 24c and 24d, developer application rollers 25a, 25b, 25c and 25d, and a toner container. The latter cleaning units 5a, 5b, 5c, 5d have photosensitive drums 1a, 1b, 1c, 1d, charging rollers 2a, 2b, 2c, 2d, cleaning units 8a, 8b, 8c, 8d, and transfer residual toner containers. doing.

  The photosensitive drums 1a, 1b, 1c, and 1d are formed by applying an organic photoconductive layer (OPC) on the outer peripheral surface of an aluminum cylinder, and both ends thereof are rotatably supported by flanges. . The driving force is transmitted from one end of the photosensitive drums 1a, 1b, 1c, and 1d from a driving motor (not shown), whereby the photosensitive drums 1a, 1b, 1c, and 1d rotate in the clockwise direction indicated by the arrows in FIG.

  The charging rollers 2a, 2b, 2c and 2d are conductive rollers formed in a roller shape. The rollers are brought into contact with the surfaces of the photosensitive drums 1a, 1b, 1c and 1d, and a charging voltage is applied by a power supply circuit (not shown) to uniformly charge the surfaces of the photosensitive drums 1a, 1b, 1c and 1d. The exposure unit 3 is disposed vertically below the process cartridge 7 (7a, 7b, 7c, 7d), and performs exposure based on an image signal on the photosensitive drums 1a, 1b, 1c, 1d.

  In the toner container, toners of respective colors of yellow (Y), magenta (M), cyan (C) and black (Bk) are stored.

  The developing rollers 24a, 24b, 24c, and 24d are disposed adjacent to the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d, and are rotationally driven by a drive unit (not shown) and apply a voltage. The photosensitive drums 1a, 1b, 1c and 1d are developed on the surface.

  With the above configuration, toner images of Y, M, C, and Bk are formed on the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d. The toner images formed on the surfaces of the photosensitive drums 1a, 1b, 1c and 1d are sequentially primary-transferred to the surface of the intermediate transfer belt 12e. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a, 1b, 1c and 1d is removed by the cleaning means 8a, 8b, 8c and 8d and collected in the transfer material toner container in the cleaning units 5a, 5b, 5c and 5d. .

(2) Transfer to Transfer Material and Fixing Process Transfer of the toner image to the transfer material S is carried out by the sheet feeding device 13 by the transfer device to the secondary transfer unit 15 and the secondary transfer unit 15. The intermediate transfer unit 12 carries the toner image formed by the primary transfer process, and conveys the toner image to the secondary transfer unit 15. The fixing device 14 is located downstream of the secondary transfer portion 15 and fixes the toner image transferred to the transfer material on the transfer material S.

  The sheet feeding device 13 mainly includes a sheet feeding cassette 11 for storing the transfer material S, a sheet feeding roller 9, a separation unit 23, and a pair of registration rollers 10 for nipping and transferring the transfer material S. The fixing device 14 includes a fixing film 14 a, a pressure roller 14 b, a heating body 14 c, and a pair of sheet discharge rollers 20.

  The sheet feeding cassette 11 can be pulled out in the front side of the apparatus body (in FIG. 1, the left side of the apparatus body). After the user pulls out the sheet feeding cassette 11 and withdraws the sheet feeding cassette 11 from the apparatus main body 100, the transfer material S can be replenished by setting the transfer material S in the sheet feeding cassette 11 and inserting it into the apparatus main body 100. The sheet feeding roller 9 is in pressure contact with the transfer material S stored in the sheet feeding cassette 11 and rotates at a predetermined control timing to feed the transfer material S, and the transfer material S is separated one by one by the separation unit 23. It is separated and fed. Thereafter, the transfer material S is conveyed to the secondary transfer portion 15 by the registration roller pair 10.

  In the secondary transfer unit 15, a bias is applied to the secondary transfer unit 16, and the toner image on the intermediate transfer belt 12e is transferred onto the transfer material S conveyed to the secondary transfer unit 15.

  The fixing film 14a is an endless cylindrical belt, and the outer peripheral surface of the fixing film 14a is disposed on the side of the toner image on the transfer material S. The heating body 14c is disposed inside the fixing film 14a, and the pressure roller 14b is in pressure contact with the fixing film 14a. The pressure roller 14b is rotationally driven by a driving means (not shown), and the fixing film 14a is rotated along with it, and the fixing film 14a is heated by the heating member 14c. The transfer material S conveyed from the secondary transfer unit 15 is nipped and conveyed by the fixing film 14 a and the pressure roller 14 b, and the toner image is heated and fixed on the transfer material S. Thereafter, the transfer material S on which the toner image is fixed is nipped and conveyed by the discharge roller pair 20 and discharged onto the discharge tray.

[Intermediate transfer unit]
In the present embodiment, the intermediate transfer unit 12 is a unit that is detachable from the apparatus main body. As shown in FIG. 2, the intermediate transfer unit 12 is configured to be attachable to and detachable from the apparatus main body 100 in the direction A indicated by the arrow.

  The intermediate transfer unit 12 mainly includes an intermediate transfer belt (intermediate transfer material) 12e, a drive roller 12f, a driven roller 12g, primary transfer rollers 12a, 12b, 12c, and 12d as primary transfer units, cleaning unit 22, primary transfer separation A means 30 is provided. The intermediate transfer belt 12e is stretched around a driving roller 12f and a driven roller 12g. The driven roller 12g is biased by a biasing unit in a direction E shown by an arrow in FIG. 1, and applies a predetermined tension to the intermediate transfer belt 12e.

  Since the drive roller 12f is rotationally driven by a motor (not shown) or the like, the intermediate transfer belt 12e rotates at a predetermined speed in the F direction indicated by the arrow in FIG.

  The primary transfer rollers 12a, 12b, 12c, and 12d are disposed on the inner side of the intermediate transfer belt 12e so as to face the photosensitive drums 1a, 1b, 1c, and 1d. It is biased to. By applying a voltage to the primary transfer rollers 12a, 12b, 12c and 12d, the toner images formed on the surfaces of the photosensitive drums 1a, 1b, 1c and 1d are primarily transferred onto the intermediate transfer belt 12e. The toner images of four colors are superimposed and transferred onto the intermediate transfer belt, and the toner image on the intermediate transfer belt 12 is conveyed to the secondary transfer portion 15.

  After the secondary transfer, the toner remaining on the intermediate transfer belt 12e is removed by the cleaning means 22, and the toner collection container (not shown) disposed in the apparatus main body 100 via the transfer residual toner conveyance path (not shown). (See illustration).

The intermediate transfer unit 12 has a separation structure of primary transfer rollers corresponding to Y, M, and C, which are in contact with the photosensitive drum 1 via the intermediate transfer belt 12e at the time of color image formation. The purpose of this is to prevent rubbing with the photosensitive drum 1 that is not used when forming a mono image, and to prolong the life of the photosensitive drum 1.
FIG. 9 and FIG. 10 show an example of the primary transfer separating means 30 in the present embodiment.

  The primary transfer separating means 30 mainly includes a cam shaft 32, slide members 33a and 33b, and cam members 34a and 34b. At both ends of the cam shaft 32, cam members 34a and 34b having a target shape are disposed, and slide members 33a and 33b are disposed at both ends of the primary transfer rollers 12a, 12b and 12c. The position of the primary transfer rollers 12a, 12b and 12c relative to the photosensitive drums 1a, 1b and 1c can be changed by moving the slide member left and right.

  At the time of color image formation, as shown in FIG. 9, the cam members 34a and 34b are in the phase G state, and the slide members 33a and 33b are held in the position J state. As a result, each primary transfer roller 12a, 12b, 12c, 12d abuts on each photosensitive drum 1a, 1b, 1c, 1d via the intermediate transfer belt 12e.

  As shown in FIG. 10, since the cam shaft 32 receives power by a drive transmission device (described later) and the cam members 34a and 34b rotate in the C direction in the drawing, the slide members 33a and 33b move in the D direction in the drawing . At the time of mono image formation, as shown in FIG. 5, the cam members 34a and 34b are in the phase H state, and the slide members 33a and 33b are held in the position K state. The primary transfer rollers 12a, 12b and 12c corresponding to Y, M and C are moved and held by the slide members 33a and 33b to the positions retracted from the photosensitive drums 1a, 1b and 1c against the biasing direction and held. It separates from drums 1a, 1b, and 1c. When the cam members 34a and 34b further rotate in the direction C in the drawing, the state returns to the phase G state, and the slide members 33a and 33b also become the position J state.

[Drive transmission device]
The drive transmission device 40 in the present embodiment has a drive coupling 41 which is a first coupling described below and a driven coupling which is a second coupling. The first coupling is provided on the device body and is a coupling that is rotated by power from a drive source. The second coupling is provided on the unit and is a coupling that rotates in mesh with the first coupling.

  FIGS. 3-8 show an example of the drive transmission apparatus 40 in this Embodiment. Hereinafter, the configuration of the drive transmission device 40 will be described.

  The apparatus body 100 is provided with a drive coupling 41 which is a first coupling, a drive motor 43, a transmission gear 44a, and a guide member 46. The drive coupling 41, which is the first coupling, is rotated by the power of the drive motor 43. The intermediate transfer unit 12 is provided with a driven coupling 42, which is a second coupling, an urging member 45, and a transmission gear train 44b. As shown in FIG. 4, the biasing member 45 is a spring, and biases in the B direction, that is, toward the main body of the apparatus. The driven coupling 42 is disposed at a position facing the drive coupling 41 when the intermediate transfer unit 12 is mounted on the apparatus main body 100. The driven coupling 42, which is the second coupling, is rotatable by meshing with the drive coupling 41, which is the first coupling.

  The guide member 46 is disposed in the apparatus main body such that the driven coupling 42 contacts when the intermediate transfer unit 12 is attached and detached. Further, on the inlet side when the intermediate transfer unit 12 is attached to the apparatus main body 100, an inclined surface 46a for retracting the driven coupling 42 in the illustrated M direction is provided.

  As shown in FIG. 4, the transmission gear 44a is disposed to connect the drive motor 43 and the drive coupling 41, and the transmission gear train 44b connects the driven coupling 42 and the camshaft 32. It is arranged as follows.

  As shown in FIG. 5, the drive coupling 41 provided in the apparatus main body has a concave shape. Furthermore, the driven coupling 42 has a convex shape that enters into the concave coupling. However, the drive transmission device according to the present embodiment is not limited to the above configuration, and either one of the drive coupling 41 and the driven coupling 42 has a concave shape, and the other coupling has a convex shape. Any shape is acceptable.

  The drive coupling has a T-shaped first engagement portion 41b. Furthermore, the drive coupling 41 having a concave shape has an inclined surface 41e on the inner peripheral portion. The driven coupling 42, which has a convex shape, has a second engaging portion 42a as a convex portion. When the drive coupling 41 and the driven coupling 42 are engaged with each other, the second engaging portion 42a of the driven coupling faces the inner surface 41a of the drive coupling. Similarly, in a state in which the drive coupling 41 and the driven coupling 42 are engaged, the first engagement portion 41b of the drive coupling faces the inner surface 42b of the driven coupling.

  Further, the drive coupling 41 and the driven coupling 42 can be engaged in a single phase to transmit the drive.

  The inclined surface 41e of the drive coupling is provided on the inner peripheral portion of the drive coupling 41, and in a state where the intermediate transfer unit 12 is mounted on the main body, the second engagement portion 42a of the driven coupling 42 Contact. As shown in FIG. 3, the driven coupling 42 is biased toward the drive coupling 41 by a biasing member 45 in a direction B which is substantially perpendicular to the direction A, which is the mounting / removing direction of the unit. . The B direction is parallel to the rotational axis of both couplings.

  The drive motor 43 is rotationally driven based on the control signal, and the drive coupling 41 rotates in the L direction shown in the drawing. As shown in FIG. 5D, with the rotation of the drive coupling 41, the contact surface 41c of the first engagement portion 41b meshes with the contact surface 42c of the second engagement portion. That is, the contact surface 41 c of the first engagement portion of the drive coupling 41 to which the drive force is transmitted by the drive motor presses the contact surface 42 c of the second engagement portion of the driven coupling 42. As a result, the rotational force is transmitted from the drive coupling 41 to the driven coupling 42, and the driven coupling 42 rotates in the L direction in the drawing. At this time, portions 41c and 42c that transmit the rotational drive are configured to transmit the force in the rotational direction. Since the contact surfaces 41c and 42c are engaged along an axis substantially perpendicular to the rotational direction L, the force pressing the driven coupling 42 in the rotational axis direction against the B direction, which is the biasing direction, during rotation is It does not occur.

  Next, the case where the intermediate transfer unit 12 is pulled out (disengaged) from the apparatus main body 100 will be described. When the drive coupling 41 and the driven coupling 42 are engaged with each other, the second engagement portion 42a of the driven coupling is in contact with the inclined surface 41e of the drive coupling. Therefore, when the intermediate transfer unit 12 is pulled out of the apparatus main body 100, when the force (extraction force) acting in the separation direction of the intermediate transfer unit 12 acts, the biasing direction B to the driven coupling 42 by the inclined surface 41e. The force of moving in the illustrated M direction works. Then, the driven coupling 42 is temporarily retracted from the drive coupling 41 in the illustrated M direction. As a result, the engagement between the first engagement portion 41 b and the second engagement portion 42 a is released. Further, since the driven coupling 42 is in contact with the guide member 46 and continues to retract in the illustrated M direction which is opposite to the biasing direction B, the intermediate transfer unit 12 can be extracted from the apparatus main body 100.

  This will be described in more detail with reference to FIGS. 6 and 7. FIG. 6 shows the state of the drive coupling and the driven coupling before the intermediate transfer unit starts to be disengaged, and FIG. 7 shows that the engagement of the first engagement portion 41b and the second engagement portion 42a is released. The states are shown respectively.

  (A) of FIG. 6 and FIG. 7 is a perspective view showing the state of the drive coupling 41 and the driven coupling 42, and (b) shows the state of the drive coupling 41 and the driven coupling 42 as a rotating shaft And a schematic view seen from a direction perpendicular to the 6 and 7 (c) are schematic views of the drive coupling 41 and the driven coupling 42 as viewed from the direction parallel to the rotation axis.

  Before the intermediate transfer unit is disengaged, as shown in FIG. 6B, the second engagement of the driven coupling located on the most upstream side in the intermediate transfer unit detachment direction in the second engagement portion 42a. There is a sufficient gap in the rotational direction between the mating portion (shown as 42f in FIG. 6, hereinafter the second engaging portion 42f) and the contact surface 41c of the first engaging portion 41b of the drive coupling. Yes.

  When the unit is pulled out of the apparatus main body in a direction perpendicular to the rotation shaft of the drive coupling 41, the force acting in the separation direction of the intermediate transfer unit causes the second engaging portion 42f to approach the contact surface 41c. The driven coupling 42 rotates. At this time, the driven coupling 42 is located at a position different from the rotation axis of the drive coupling 41 and in which the drive coupling 41 and the driven coupling 42 are in contact with each other as the center of rotation. As shown in FIGS. 6 (c) and 7 (c), the second engaging portion located between the second engaging portion 42f and the first engaging portion 41b is a second engaging portion. It is 42h. In the present embodiment, a position k at which the second engaging portion 42h and the contact surface 41c contact each other is defined as a center k of rotation.

  When the driven coupling 42 starts to rotate about the position k, the second engagement portion 42 f approaches the contact surface 41 c of the first engagement portion, and thus the second engagement portion 42 f and the contact surface The gap between 41c decreases. When the driven coupling 42 rotates, the second engaging portion (42g in FIG. 7) of the driven coupling located at the most downstream side in the intermediate transfer unit detachment direction in the second engaging portion 42a. Hereinafter, the second engaging portion 42g) moves in the separation direction of the intermediate transfer unit along the inclined surface 41e of the drive coupling. When the second engaging portion 42g moves along the inclined surface 41e, the driven coupling 42 retracts in the M direction in the drawing. As a result, as shown in FIG. 7, the engagement between the first engagement portion and the second engagement portion is released. That is, the contact surface 42c of the second engaging portion is separated from the contact surface 41c of the first engaging portion. As shown in FIG. 7, the rotation shaft of the driven coupling 42 with respect to the rotation shaft of the drive coupling 41 is until the engagement of the second engagement portion 42 a and the first engagement portion 41 b is released. And the distance for moving in the unit leaving direction is β.

  Next, when pulling out the unit from the apparatus main body in the direction perpendicular to the rotation axis of the drive coupling 41, the rotation shaft of the driven coupling 42 is the drive coupling 41 by the force acting in the detachment direction of the unit. The structure which can move to a unit detachment direction rather than a rotating shaft is demonstrated. As can be seen from FIG. 5, the driven coupling 42 has an area large enough to fit the drive coupling 41. That is, when the drive coupling 41 and the driven coupling 42 mesh and rotate, a gap is created.

As shown in FIG. 8, the maximum distance by which the rotation axis of the driven coupling 42 can move in the unit separating direction with respect to the rotation axis of the drive coupling 41 is α.
In the drive transmission device of the present embodiment, α is configured to be larger than β. When α is greater than or equal to β, when the driven coupling 42 rotates around the position k, the driven coupling is performed before the second engaging portion 42 f contacts the first engaging portion 41 b. Evacuation of 42 in the M direction is completed.

  That is, in the coupling configuration in the present embodiment, the engagement between the driven coupling 42 and the drive coupling 41 is released simply by pulling out the intermediate transfer unit 12 from the apparatus main body 100, and the first engagement portion 41b and the first engagement portion 41b are removed. The engagement of the two engaging portions 42a is released.

  Contrary to the above, when the intermediate transfer unit 12 is attached to the main body of the image forming apparatus 100, the driven coupling 42 is in contact with the guide member 46 of the apparatus main body 100, and thus retracts in the illustrated M direction. By this, the driven coupling 42 can be smoothly moved to the meshing position with the drive coupling 41. Then, in a state in which the rotational axis of the driven coupling 42 and the rotational axis of the drive coupling 41 substantially coincide with each other, as described above, when the rotational phase of the coupling is in phase, the coupling engages and the intermediate transfer unit 12 The mounting of the device on the device body 100 is completed.

  In the drive transmission device of the present embodiment, it is possible to transmit the drive from the drive coupling 41 to the driven coupling 42 by meshing in a single phase. From this, it is possible to control the phase of the driven coupling 42, that is, the phase of the cam shaft 32 in the present embodiment, based on the amount of rotation of the drive motor 43.

  Further, the drive transmission device of the present embodiment may be configured as long as one of the outer peripheral portion of the convex coupling and the inner peripheral portion of the concave coupling has the inclined surface 41 e. Further, as shown in FIG. 11, the second engaging portion 42a of the driven coupling 42 also has an inclined surface, that is, the outer peripheral portion of the convex coupling and the inner peripheral portion of the concave coupling. Alternatively, both sides may have an inclined surface. By providing inclined surfaces on both the drive coupling 41 and the driven coupling 42, the driven coupling 42 can be retracted more smoothly in the illustrated M direction opposite to the biasing direction B. In the case of the phase shown in FIG. 12A, the driven coupling 42 rotates around the position k shown in FIG. 12A, and the driven coupling 42 is in the M direction along the inclined surface. Can be saved. Further, in the case of the phase shown in FIG. 12B, the driven coupling 42 does not rotate around the contact position of the second engagement portion 42a and the first engagement portion 41b as a rotation center. The unit can be retracted in the M direction along the inclined surface by a force acting in the detachment direction of the unit.

Second Embodiment
In the present embodiment, a drive transmission device in which the drive coupling 51 and the driven coupling 52 are engaged in a plurality of phases will be described. The configuration other than the drive transmission device is the same as that of the first embodiment.

  When it is not necessary to control the phase on the target unit side with the drive motor provided on the main body side, the same effect can be obtained with the coupling configuration shown in FIG. For example, a drive transmission device or the like for rotating the rollers on the unit side at a predetermined direction at a speed corresponds to this.

  Reference numeral 51 in FIG. 13 denotes a drive coupling corresponding to 41 in the first embodiment, and reference numeral 52 denotes a driven coupling corresponding to 42 in the first embodiment. The coupling according to the present embodiment is the same as that according to the first embodiment except that the shapes of the engagement portions of the driven coupling 52 and the drive coupling 51 are different from those of the coupling according to the first embodiment.

  As shown in FIGS. 14 to 15, as in the first embodiment, the rotation of the driven coupling 52 is caused before the engagement of the second engagement portion 52a and the first engagement portion 51b is released. The distance traveled by the axis with respect to the rotational axis of the drive coupling 51 in the unit separating direction is β.

  Furthermore, as shown in FIG. 16, as in the first embodiment, the maximum movable distance of the rotation shaft of the driven coupling 52 with respect to the rotation shaft of the drive coupling 51 is α. When α is greater than or equal to β, when the driven coupling 52 rotates around the position k, the driven coupling is performed before the second engagement portion 52 f contacts the first engagement portion 51 b. Evacuation of 52 in the M direction is completed.

  Furthermore, as shown in FIG. 17, the second engaging portion 52a of the driven coupling 52 may also have an inclined surface 51e. By providing inclined surfaces on both the drive coupling 51 and the driven coupling 52, the driven coupling 52 can be retracted more smoothly in the illustrated M direction opposite to the biasing direction B.

Third Embodiment
In the present embodiment, a drive transmission device in which the drive coupling 61 and the driven coupling 62 mesh in a plurality of phases will be described. The configuration other than the drive transmission device is the same as that of the first embodiment. As in the second embodiment, the drive motor provided on the main body side can be used when it is not necessary to control the phase on the target unit side.

  In FIG. 18, reference numeral 61 denotes a drive coupling corresponding to 41 in the first embodiment, and reference numeral 62 denotes a driven coupling corresponding to 42 in the first embodiment. The coupling according to the present embodiment is the same as that according to the first embodiment except that the shapes of the engaging portions of the driven coupling 62 and the driving coupling 62 are different from those of the coupling according to the first embodiment.

  As shown in FIGS. 19 to 20, as in the first embodiment, the rotation of the driven coupling 62 before the engagement of the second engagement portion 62a and the first engagement portion 61b is released. The distance traveled by the axis with respect to the rotational axis of the drive coupling 61 in the unit separating direction is β.

  Furthermore, as shown in FIG. 21, as in the first embodiment, the maximum movable distance of the rotation shaft of the driven coupling 62 with respect to the rotation shaft of the drive coupling 61 is α. When α is equal to or greater than β, the driven coupling 62 can be retracted smoothly from the drive coupling 61.

  Furthermore, as shown in FIG. 22, the second engaging portion 62a of the driven coupling 62 may also have an inclined surface 61e. By providing inclined surfaces on both of the drive coupling 61 and the driven coupling 62, the driven coupling 62 can be retracted more smoothly in the illustrated M direction opposite to the biasing direction B.

Embodiment 4
In the present embodiment, in the drive transmission apparatus described in the first embodiment, the function in the case where the driven coupling 42 has an arc surface 42i and the arc surface 42i abuts on the drive coupling 41 and makes contact is shown in FIG. This will be described using FIG. The symbols shown in FIG. 23 are the same as the symbols used in the first embodiment.

  The driven coupling 42 is biased toward the drive coupling 41 by the biasing member 45, and the arc surface 42i contacts the inclined surface 41e of the drive coupling 41, and the axial direction of the driven coupling 42 The position is determined.

  Here, even when the position of the mounted intermediate transfer unit 12 deviates within the range of variation with respect to the apparatus main body 100, by adopting this configuration, even if there is some eccentricity due to positional deviation, the rotation Power can be transmitted.

(Other embodiments)
In the above embodiment, although an example in which the coupling is used as a drive transmission device between the intermediate transfer unit 12 and the apparatus main body as a unit is shown, the present invention is also applicable to other units and couplings. For example, the coupling between the developing unit (cartridge) and the apparatus main body, and the coupling between the process cartridge 7 of the first embodiment and the apparatus main body. As shown in FIGS. 24 and 25, the process cartridge 7 may have a driven coupling 42. Further, although the shape of 41 is shown as the drive coupling and the shape of 42 is shown as the driven coupling, it is possible to implement even if the relationship between these is reversed. Furthermore, when the unit is attached to the main assembly of the apparatus, etc., the function relating to the engagement of the drive coupling 41 and the driven coupling 42 is similarly exhibited regardless of which of the couplings is recessed.

Reference Signs List 1 photosensitive drum 2 charging roller 3 exposure unit 4 developing unit 4a to 4d developing unit 5a to 5d cleaning unit 7 process cartridge 8 cleaning unit 9 sheet feeding roller 10 registration roller pair 11 sheet feeding cassette 12 intermediate transfer unit 12a to 12d (primary) Transfer means 12e Intermediate transfer belt (intermediate transfer material)
Reference Signs List 12 f driving roller 12 g driven roller 13 sheet feeding device 14 fixing device 15 secondary transfer unit 16 secondary transfer unit 20 sheet discharging roller pair 22 cleaning unit 23 separating unit 24 a to 24 d developing roller 25 a to 25 d developer application roller 30 primary transfer separation Means 31 biasing member 32 cam shaft 33 slide member 34 cam member 40 drive transmission device 41, 51, 61 drive coupling 42, 52, 62 driven coupling 43 drive motor 44 transmission gear 45 biasing member 100 image forming apparatus S Transfer material A, B, C, D, E, F, L, M direction G, H phase J, K position

Claims (10)

The device body,
A unit detachably attachable to the device body;
A first coupling provided on the device body and rotated by power from a drive source, and a second coupling provided on the unit and engaged with the first coupling and rotating;
Have
The first coupling includes a first protrusion, and the second coupling includes a second protrusion engaged with the first protrusion, and the first coupling and the second coupling At least one of which comprises an inclined surface inclined with respect to the axis of rotation of the first coupling,
The second coupling is the first coupling by the force acting in the disengaging direction of the unit when the unit is pulled out from the apparatus main body in the direction perpendicular to the rotation axis of the first coupling. More movably in the direction of the release
The second coupling from the state wherein the first coupling the second coupling is engaged in the process of moving to the withdrawal direction, of the second coupling between the first coupling after the other is in contact with the inclined surface provided on at least one of, and parallel to the axis of rotation of the relatively said first coupling the second coupling relative to the front Symbol first coupling An image forming apparatus characterized by starting retraction in a direction.   At least one of the first coupling and the second coupling is rotatable by the force acting in the separating direction when the unit is pulled out from the device body in the separating direction. The image forming apparatus according to claim 1.   The unit is characterized in that it comprises a spring which biases the second coupling in a direction parallel to the axis of rotation of the first coupling and in a direction towards the first coupling. The image forming apparatus according to 1 or 2.   The unit according to any one of claims 1 to 3, wherein the unit is a developing unit, and the first coupling and the second coupling are couplings between the developing unit and the apparatus main body. An image forming apparatus according to claim 1.   The image forming apparatus according to any one of claims 1 to 3, wherein the unit comprises a photosensitive drum. Wherein the second coupling is provided plane intersecting the rotation axis of the second coupling, the second protrusions protruding from said plane in a direction parallel to the rotational axis of the second coupling The image forming apparatus according to any one of claims 1 to 5, wherein the image forming apparatus is a shape. The image forming apparatus according to any one of claims 1 to 5, wherein the second projection is a projection extending in a direction parallel to the rotation axis of the second coupling.   The second coupling includes another second projection, and the second projection and the other second projection when the second coupling is engaged with the first coupling. The image forming apparatus according to any one of claims 1 to 7, wherein a part of the first coupling enters a space between the two. The image forming apparatus according to claim 8 , wherein the inclined surface is formed on the another second protrusion. The inclined surface is an image forming apparatus according to any one of claims 1 to 9, characterized in that it is formed on the second protrusion before SL.

Images