JP4979839B2 - Drive transmission device and image forming apparatus - Google Patents

Abstract

A unit detachably mountable to an apparatus main assembly s provided with a coupling for receiving a rotational driving force from the apparatus main assembly. Also the apparatus main assembly is provided with a coupling to be engaged with the coupling of the unit. At least one of these couplings can be pushed in a direction parallel to a rotation shaft and one of the couplings is provided with an inclined surface. During mounting and demounting of the unit, the engagement between the couplings is released by the pushing-in of one of the couplings pushed by the inclined surface.

Description

  The present invention relates to a unit that can be attached to and detached from an image forming apparatus main body.

  In recent years, in an image forming apparatus such as an electrophotographic printer or a copying machine, downsizing and improvement in operability are 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 the cartridge can be attached to and detached from the main body of the image forming apparatus. ing. The operability is further improved by this cartridge system, and the user can easily perform maintenance of the process means such as development.

  Similarly, the intermediate transfer member of the image forming apparatus main body has a unit configuration and is detachable from the image forming apparatus main body, thereby improving operability and maintenance.

  Further, as a drive transmission device that stably and reliably transmits drive to these units that can be attached to and detached from the image forming apparatus main body, a combination of a convex portion as shown in FIG. 26 and a concave portion corresponding thereto is performed. Coupling is used.

  In Patent Document 1, the coupling on the apparatus main body side is retracted from the coupling on the unit side by the operation of opening the cover in conjunction with a cover that opens and closes the coupling pair, so that the coupling pair is disconnected, A configuration that enables the unit to be attached and detached is disclosed.

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 portion of the cover. With this mechanism, the opening / closing operability of the cover is deteriorated, and the cost is increased due to the complicated configuration.

  For example, when a link mechanism is provided on the opening / closing cover to connect and release the coupling, the coupling is released and connected every time the cover is opened and closed, and the coupling is released and connected which is not necessary. The cover will bear the load. In this case, a load such as a resistance required for releasing and coupling the coupling is applied to an operation 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 coupling the coupling becomes large, and the operability for opening and closing the cover is deteriorated.

  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 apparatus is increased in size and cost.

The unit of the present invention for solving the above problems is
A unit detachably attached to an electrophotographic image forming apparatus main body having a rotatable main body coupling for transmitting a driving force,
A rotatable unit coupling that receives the driving force from the body coupling;
The unit is movable in a first direction substantially perpendicular to a rotation axis of the unit coupling with respect to the apparatus main body when removed from the apparatus main body,
The unit coupling is movable in a second direction substantially parallel to the rotation axis of the unit coupling with respect to the main body of the unit;
One of the main body coupling or the unit coupling has an inclined portion,
The other of the main body coupling or the unit coupling has a contact portion that can contact the inclined portion,
When the unit is removed from the apparatus main body, the unit coupling is moved to the first direction in a state where the inclined portion and the abutting portion are in contact with each other. Receiving the force from the unit, the unit moves in the second direction with respect to the main body of the unit, and retracts from the main body coupling.

  According to the present invention, the coupling between the unit and the apparatus main body is released when the unit is detached from the apparatus main body.

1 is a cross-sectional view showing a main part of an image forming apparatus according to Embodiment 1 of the present invention. It is a perspective view which shows the attachment / detachment direction of the unit which concerns on Embodiment 1 of this invention. It is a top view which shows the attachment / 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. 5 is a schematic diagram illustrating a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 1 of the present invention starts to be detached. It is the schematic which shows the state by 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 separation means concerning Embodiment 1 of this invention (phase G). It is a schematic perspective view which shows the transfer separation means concerning Embodiment 1 of this invention (phase H). It is a perspective view which shows the other coupling which concerns 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. 10 is a schematic diagram illustrating a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 2 of the present invention starts to be detached. It is the schematic which shows the state by 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 which concerns on Embodiment 2 of this invention. It is a perspective view which shows the coupling which concerns on Embodiment 3 of this invention. FIG. 10 is a schematic diagram illustrating a state of drive coupling and driven coupling before the intermediate transfer unit according to Embodiment 3 of the present invention starts to be detached. It is the schematic which shows the state by 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 which concerns on Embodiment 3 of this invention. It is a perspective view which shows the coupling which concerns on 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 apparatus in background art.

(Embodiment 1)
In this embodiment, an electrophotographic four-drum color image forming apparatus is used as the apparatus body, and an intermediate transfer unit is used as a detachable unit. In this embodiment, a drive transmission device is used to transmit a 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 apparatus according to FIGS.

[Image forming apparatus]
First, the configuration of the apparatus main body 100 will be described.
FIG. 1 is a 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. A photosensitive roller 1 (2a, 2b, 2c, 2d) that uniformly charges the surface of the photosensitive drum 1 in order according to the direction of rotation of each photosensitive drum 1 is irradiated with laser based on image information. There is an exposure unit 3 that forms an electrostatic latent image on 1. Further, a developing unit 4 (4a, 4b, 4c, 4d) that attaches toner to the electrostatic latent image on the photosensitive drum 1 to visualize the toner image, and transfers 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 the post-transfer toner remaining on the surface of the photosensitive drum 1 after the transfer is disposed.

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

  The process cartridges 7a, 7b, 7c, 7d are constituted by developing units 4a, 4b, 4c, 4d and cleaning units 5a, 5b, 5c, 5d. Of these, 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 and 5d have photosensitive drums 1a, 1b, 1c and 1d, charging rollers 2a, 2b, 2c and 2d, cleaning means 8a, 8b, 8c and 8d, and a transfer residual toner container. is doing.

  Each of the photosensitive drums 1a, 1b, 1c, and 1d is formed by applying an organic photoconductive layer (OPC) to the outer peripheral surface of an aluminum cylinder, and both ends thereof are rotatably supported by flanges. . By transmitting a driving force from a driving motor (not shown) to one end of each of the photosensitive drums 1a, 1b, 1c, and 1d, the photosensitive drums 1a, 1b, 1c, and 1d are rotationally driven in a clockwise direction indicated by an arrow in FIG.

  The charging rollers 2a, 2b, 2c, and 2d are conductive rollers formed in a roller shape. This roller is 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 arranged vertically below the process cartridge 7 (7a, 7b, 7c, 7d), and performs exposure based on the image signal to the photosensitive drums 1a, 1b, 1c, 1d.

Each toner container contains toner of each color of yellow (Y), magenta (M), cyan (C), and black (Bk).
The developing rollers 24a, 24b, 24c, and 24d are arranged adjacent to the surface of the photosensitive drums 1a, 1b, 1c, and 1d, and are driven to rotate by a driving unit (not shown) and apply a voltage. Development is performed on the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d.

  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 transferred onto the surface of the intermediate transfer belt 12e in sequence. Thereafter, the toner remaining on the surface of the photosensitive drums 1a, 1b, 1c, and 1d is removed by the cleaning units 8a, 8b, 8c, and 8d and collected in a transfer material toner container in the cleaning units 5a, 5b, 5c, and 5d. .

(2) Transfer onto Transfer Material and Fixing Process Transfer of the toner image onto the transfer material S is performed by the secondary transfer unit 15 after the transfer material is conveyed to the secondary transfer unit 15 by the paper feeding device 13. The intermediate transfer unit 12 carries a 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 on the downstream side of the secondary transfer unit 15 and fixes the toner image transferred onto the transfer material onto the transfer material S.

  The sheet feeding device 13 is mainly composed of a sheet feeding cassette 11 for storing the transfer material S, a sheet feeding roller 9, a separating unit 23, and a registration roller pair 10 for nipping and conveying 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 paper discharge roller pair 20.

  The paper feed cassette 11 can be pulled out toward the front of the apparatus main body (the left side of the apparatus main body in FIG. 1). The user can replenish the transfer material S by pulling out the paper feed cassette 11 and pulling it out from the apparatus main body 100, setting the transfer material S in the paper feed cassette 11, and inserting the transfer material S into the apparatus main body 100. The feed roller 9 is in pressure contact with the transfer material S stored in the paper feed cassette 11 and rotates at a predetermined control timing, so that the transfer material S is sent out, and the transfer material S is separated one by one by the separating means 23. Separated and fed. Thereafter, the transfer material S is conveyed to the secondary transfer unit 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 12 e is transferred onto the transfer material S conveyed to the secondary transfer unit 15.

  The fixing film 14 a is an endless cylindrical belt, and the outer peripheral surface of the fixing film 14 a is arranged on the toner image surface side on the transfer material S. The heating element 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 accordingly, and the fixing film 14a is heated by the heating body 14c. The transfer material S conveyed from the secondary transfer unit 15 is nipped and conveyed between the fixing film 14a and the pressure roller 14b, 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 can be attached to and detached from the apparatus main body. As shown in FIG. 2, the intermediate transfer unit 12 is configured to be detachable from the apparatus main body 100 in the A direction indicated by the arrow.

  The intermediate transfer unit 12 mainly includes an intermediate transfer belt (intermediate transfer material) 12e, a driving roller 12f, a driven roller 12g, primary transfer rollers 12a, 12b, 12c, and 12d as primary transfer units, a cleaning unit 22, and primary transfer separation. The means 30 is constituted. The intermediate transfer belt 12e is stretched around a driving roller 12f and a driven roller 12g. The driven roller 12g is urged by the urging means in the direction E shown by the 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 inside the intermediate transfer belt 12e so as to face the photosensitive drums 1a, 1b, 1c, and 1d. Is being energized. 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. Four color toner images are transferred onto the intermediate transfer belt in a superimposed manner, and the toner images on the intermediate transfer belt 12 are conveyed to the secondary transfer unit 15.

  After the secondary transfer, the toner remaining on the intermediate transfer belt 12e is removed by the cleaning unit 22 and passes through a transfer residual toner conveyance path (not shown), and a toner recovery container (not shown) disposed in the apparatus main body 100. (Shown).

  The intermediate transfer unit 12 has a primary transfer roller separation structure corresponding to Y, M, and C that are in contact with the photosensitive drum 1 via the intermediate transfer belt 12e during color image formation. This is to prevent sliding with the photosensitive drum 1 that is not used during mono image formation and to prolong the life of the photosensitive drum 1.

9 and 10 show an example of the primary transfer separation means 30 in the present embodiment.
The primary transfer separation means 30 mainly includes a cam shaft 32, slide members 33a and 33b, and cam members 34a and 34b. Cam members 34a and 34b, which are target shapes, are disposed at both ends of the cam shaft 32, 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 to the left and right.

  During color image formation, the cam members 34a and 34b are in the phase G state as shown in FIG. 9, and the slide members 33a and 33b are held in the position J. As a result, the primary transfer rollers 12a, 12b, 12c, and 12d abut on the photosensitive drums 1a, 1b, 1c, and 1d via the intermediate transfer belt 12e.

  As shown in FIG. 10, the cam shaft 32 receives power from a drive transmission device (described later), and the cam members 34a and 34b rotate in the direction C shown in the figure, so that the slide members 33a and 33b move in the direction D in the figure. . During mono image formation, the cam members 34a and 34b are in the phase H state as shown in FIG. 5, and the slide members 33a and 33b are held in the position K. Then, 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, in the opposite direction to the urging direction. Separated from the drums 1a, 1b, 1c. Further, when the cam members 34a and 34b rotate in the direction C shown in the drawing, the state returns to the phase G state, and the slide members 33a and 33b are also in the position J.

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

  3 to 8 show an example of the drive transmission device 40 in the present embodiment. Hereinafter, the configuration of the drive transmission device 40 will be described.

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

  The guide member 46 is disposed in the apparatus main body so that the driven coupling 42 contacts when the intermediate transfer unit 12 is attached or detached. Further, on the entrance side when the intermediate transfer unit 12 is mounted on the apparatus main body 100, an inclined surface 46a for retracting the driven coupling 42 in the M direction in the figure is provided.

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

  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 the concave coupling. However, the drive transmission device according to the present embodiment is not limited to the above configuration, and 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 periphery. The driven coupling 42 having a convex shape has a second engaging portion 42a as a convex portion. In a state where the drive coupling 41 and the driven coupling 42 are engaged with each other, the second engagement portion 42a of the driven coupling faces the inner surface 41a of the drive coupling. Similarly, when the drive coupling 41 and the driven coupling 42 are engaged with each other, 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 mesh with each other and transmit the drive.

  The inclined surface 41e of the drive coupling is provided on the inner peripheral portion of the drive coupling 41. When the intermediate transfer unit 12 is mounted on the main body, the inclined surface 41e contacts the second engagement portion 42a of the driven coupling 42. Touch. As shown in FIG. 3, the driven coupling 42 is urged toward the drive coupling 41 by the urging member 45 in the B direction that is substantially perpendicular to the A direction that is the attaching / detaching direction of the unit. . The B direction is parallel to the rotational axis of both couplings.

  The drive motor 43 is driven to rotate based on the control signal, and the drive coupling 41 is rotated in the L direction in the drawing. As shown in FIG. 5D, as the drive coupling 41 rotates, 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 driving force is transmitted by the drive motor presses the contact surface 42 c portion of the second engagement portion of the driven coupling 42. As a result, a 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, the portions 41c and 42c that transmit rotational driving have a shape that transmits force in the rotational direction. Since the contact surfaces 41c and 42c are engaged by an axis substantially perpendicular to the rotation direction L, the force that pushes the driven coupling 42 in the rotation axis direction against the B direction which is the urging direction during rotation is not generated. Does not occur.

  Next, a case where the intermediate transfer unit 12 is pulled out (detached) 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 pulling out the intermediate transfer unit 12 from the apparatus main body 100, if a force (pulling force) acting in the separation direction of the intermediate transfer unit 12 is exerted, the biasing direction B is applied to the driven coupling 42 by the inclined surface 41e. A force that moves in the M direction shown in the reverse direction works. Then, the driven coupling 42 is temporarily retracted from the driving coupling 41 in the M direction in the figure. As a result, the engagement between the first engagement portion 41b and the second engagement portion 42a is released. Further, since the driven coupling 42 contacts the guide member 46 and continues to retract in the M direction shown in the figure, which is opposite to the urging 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. FIG. 6 shows the state of the drive coupling and the driven coupling before the intermediate transfer unit starts to be detached, and FIG. 7 shows the state where the engagement of the first engagement portion 41b and the second engagement portion 42a is released. Each state is shown.

  6A and 7B are perspective views showing the state of the drive coupling 41 and the driven coupling 42, and FIG. 6B is a perspective view showing the state of the drive coupling 41 and the driven coupling 42. It is the schematic diagram seen from the perpendicular direction. FIGS. 6 and 7C are schematic views of the state of the drive coupling 41 and the driven coupling 42 as seen from the direction parallel to the rotation axis.

  Before the intermediate transfer unit is detached, as shown in FIG. 6B, the second engagement of the driven coupling located on the most upstream side in the intermediate transfer unit removal direction in the second engaging portion 42a. The contact portion 41c of the joint portion (denoted by 42f in FIG. 6, hereinafter referred to as the second engagement portion 42f) and the first engagement portion 41b of the drive coupling is configured to have a sufficient clearance in the rotational direction. It is.

  When the unit is pulled out from the apparatus main body in a direction perpendicular to the rotation axis of the drive coupling 41, the second engaging portion 42f approaches the contact surface 41c by the force acting in the direction of detachment of the intermediate transfer unit. The driven coupling 42 rotates. At this time, the driven coupling 42 is located at a position different from the rotational axis of the driving coupling 41 and the position where the driving coupling 41 and the driven coupling 42 are in contact with each other. As shown in FIG. 6C and FIG. 7C, the second engagement portion positioned between the second engagement portion 42f and the first engagement portion 41b is replaced with the second engagement portion. 42h. In this embodiment, the position k at which the second engaging portion 42h and the contact surface 41c come into contact is set as the center k of rotation.

  When the driven coupling 42 starts to rotate around the position k, the second engagement portion 42f approaches the contact surface 41c of the first engagement portion, and therefore the second engagement portion 42f and the contact surface The clearance between 41c decreases. When the driven coupling 42 rotates, the second engaging portion of the driven coupling (42g in FIG. 7) located on the most downstream side in the intermediate transfer unit detaching direction in the second engaging portion 42a. Hereinafter, the second engaging portion 42g) moves in the direction of detachment 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 meshing between the first engaging portion and the second engaging portion is released. That is, the contact surface 42c of the second engagement portion is separated from the contact surface 41c of the first engagement portion. As shown in FIG. 7, the rotational axis of the driven coupling 42 is relative to the rotational axis of the drive coupling 41 until the engagement between the second engagement portion 42 a and the first engagement portion 41 b is released. The distance to move in the unit removal direction is β.

  Next, when the unit is pulled out from the apparatus main body in a direction perpendicular to the rotation axis of the drive coupling 41, the rotation axis of the driven coupling 42 causes the drive coupling 41 to move. A structure capable of moving in the unit removal direction from the rotating shaft will be described. As can be seen from FIG. 5, the driven coupling 42 has a sufficiently wide area in which the driving coupling 41 fits. That is, when the drive coupling 41 and the driven coupling 42 mesh with each other and rotate, a gap is created.

  As shown in FIG. 8, the maximum distance that the rotational axis of the driven coupling 42 can move in the unit disengagement direction with respect to the rotational 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 β or more, when the driven coupling 42 rotates around the position k, the driven coupling 42f comes into contact with the first engaging portion 41b before the second engaging portion 42f contacts the first engaging portion 41b. The retreat of 42 in the M direction is completed.

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

  On the contrary, when the intermediate transfer unit 12 is mounted on the main body of the image forming apparatus 100, the driven coupling 42 comes in contact with the guide member 46 of the main body 100, so that it retracts in the M direction in the figure. Thus, the driven coupling 42 can smoothly move to the meshing position with the drive coupling 41. In the state where the rotation axis of the driven coupling 42 and the rotation axis of the drive coupling 41 are substantially coincident with each other, as described above, when the rotation phase of the coupling is matched, the coupling is engaged, and the intermediate transfer unit 12 is engaged. Is attached to the apparatus main body 100.

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

  Moreover, the drive transmission apparatus of this Embodiment should just be the structure in which one of the outer peripheral part of a convex coupling and the inner peripheral part of a concave coupling has the inclined surface 41e. Furthermore, as shown in FIG. 11, the second engaging portion 42a of the driven coupling 42 also has an inclined surface, that is, an outer peripheral portion of the convex coupling and an inner peripheral portion of the concave coupling. Further, a configuration having inclined surfaces on both sides may be used. By providing inclined surfaces on both the drive coupling 41 and the driven coupling 42, the driven coupling 42 can retreat more smoothly in the M direction shown in the figure, which is 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 evacuated. In the case of the phase shown in FIG. 12B, the driven coupling 42 does not rotate with the contact position between the second engagement portion 42a and the first engagement portion 41b as the rotation center. The unit can be retracted in the M direction along the inclined surface by a force acting in the direction in which the unit is detached.

(Embodiment 2)
In the present embodiment, a drive transmission device in which the drive coupling 51 and the driven coupling 52 are engaged at a plurality of phases will be described. All configurations other than the drive transmission device are the same as those in 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 for rotating the rollers on the unit side at a predetermined direction and speed corresponds to this.

  In FIG. 13, 51 is a drive coupling corresponding to 41 in the first embodiment, and 52 is a driven coupling corresponding to 42 in the first embodiment. The coupling of the present embodiment is the same as that of the first embodiment, except that the shapes of the engaging portions of the driven coupling 52 and the driving coupling 51 are different from those of the first embodiment.

  As shown in FIGS. 14 to 15, as in the first embodiment, the driven coupling 52 rotates until the engagement between the second engagement portion 52 a and the first engagement portion 51 b is released. The distance that the shaft moves in the unit disengagement direction with respect to the rotation shaft of the drive coupling 51 is β.

  Further, as shown in FIG. 16, as in the first embodiment, the maximum distance that the movable shaft of the driven coupling 52 can move in the unit disengagement direction with respect to the rotational shaft of the drive coupling 51 is α. When α is β or more, when the driven coupling 52 rotates about the position k, the driven coupling 52 comes into contact with the first engaging portion 51b before the second engaging portion 52f contacts the first engaging portion 51b. The 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 more smoothly retracted in the M direction shown in the figure, which is opposite to the biasing direction B.

(Embodiment 3)
In the present embodiment, a drive transmission device in which the drive coupling 61 and the driven coupling 62 are engaged at a plurality of phases will be described. All configurations other than the drive transmission device are the same as those in 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, 61 is a drive coupling corresponding to 41 in the first embodiment, and 62 is a driven coupling corresponding to 42 in the first embodiment. The coupling of the present embodiment is the same as that of 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 first embodiment.

  As shown in FIGS. 19 to 20, as in the first embodiment, the driven coupling 62 rotates until the engagement between the second engagement portion 62 a and the first engagement portion 61 b is released. The distance that the shaft moves in the unit disengagement direction with respect to the rotation shaft of the drive coupling 61 is β.

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

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

(Embodiment 4)
In the present embodiment, in the drive transmission apparatus described in the first embodiment, the driven coupling 42 has an arc surface 42i, and the function when the arc surface 42i hits and contacts the drive coupling 41 is illustrated in FIG. 23 will be described. The reference numerals shown in FIG. 23 are the same as those used in the first embodiment.

  The driven coupling 42 is biased toward the driving coupling 41 by the biasing member 45, and the arc surface 42 i comes into contact with the inclined surface 41 e of the driving coupling 41, so that the driven coupling 42 is axially moved. The position is determined.

  Here, even when the position of the mounted intermediate transfer unit 12 is deviated with respect to the apparatus main body 100 within the range of variation, the present configuration allows the rotation even if there is some eccentricity due to misalignment. Can transmit power.

(Other embodiments)
In the above-described embodiment, an example is shown in which a coupling is used as a drive transmission device between the intermediate transfer unit 12 and the apparatus body as the unit. However, the present invention can also be applied to other units and couplings. For example, the coupling between the developing unit (cartridge) and the apparatus main body, or the coupling between the process cartridge 7 of Embodiment 1 and the apparatus main body. As shown in FIGS. 24 and 25, the process cartridge 7 may have a driven coupling 42. Moreover, although the shape of 41 was shown as a drive coupling and the shape of 42 was shown as a to-be-driven coupling, implementation is possible even if these relations are reverse. Further, regardless of which coupling is retracted when the unit is attached to the apparatus main body, the function related to the engagement of the drive coupling 41 and the driven coupling 42 is similarly exhibited.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging roller 3 Exposure means 4 Developing unit 4a-4d Developing unit 5a-5d Cleaning unit 7 Process cartridge 8 Cleaning means 9 Paper feed roller 10 Registration roller pair 11 Paper feed cassette 12 Intermediate transfer unit 12a-12d (primary) Transfer means 12e Intermediate transfer belt (intermediate transfer material)
12f Drive roller 12g Driven roller 13 Paper feeding device 14 Fixing device 15 Secondary transfer unit 16 Secondary transfer unit 20 Paper discharge roller pair 22 Cleaning unit 23 Separating unit 24a to 24d Developing roller 25a to 25d 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 (6)

A unit detachably attached to an electrophotographic image forming apparatus main body having a rotatable main body coupling for transmitting a driving force,
A rotatable unit coupling that receives the driving force from the body coupling;
The unit is movable in a first direction substantially perpendicular to a rotation axis of the unit coupling with respect to the apparatus main body when removed from the apparatus main body,
The unit coupling is movable in a second direction substantially parallel to the rotation axis of the unit coupling with respect to the main body of the unit;
One of the main body coupling or the unit coupling has an inclined portion,
The other of the main body coupling or the unit coupling has a contact portion that can contact the inclined portion,
When the unit is removed from the apparatus main body, the unit coupling is moved to the first direction in a state where the inclined portion and the abutting portion are in contact with each other. Receiving the force from the unit, moving in the second direction relative to the main body of the unit, and retreating from the main body coupling.   The unit according to claim 1, wherein the abutting portion is another inclined portion that can abut on the inclined portion and is substantially parallel to the inclined portion.   When the unit is removed from the apparatus main body, the unit coupling is moved to the first direction by moving the unit in the first direction. On the other hand, the rotation is performed with a contact position where the unit coupling and the main body coupling are in contact with each other being at a position different from the rotation axis of the main body coupling. The unit according to 1 or 2.   The unit according to claim 3, wherein the contact position is a position where the unit coupling receives the driving force from the main body coupling. One of the inclined part or the contact part is provided on the outer periphery of the convex part,
The other of the inclined part or the contact part is provided on the inner periphery of the recess,
The unit according to any one of claims 1 to 4, wherein the unit coupling receives the driving force from the main body coupling in a state where the convex portion enters the concave portion. When rotating around the contact position where the main body coupling and the unit coupling are in contact with each other, the rotation axis of the unit coupling is the position different from the rotation axis of the main body coupling. The maximum distance among the distances that can move in the first direction is α,
The axis of rotation of the unit coupling moves in the first direction until the convex portion can be separated from the concave portion by retracting the unit coupling along the inclined surface from the main body coupling. Let β be the distance to
The unit according to claim 1, wherein α is larger than β.

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