JP6862590B2 - Drive transmission device and image forming device - Google Patents

Description

The present invention relates to a drive transmission device for transmitting a driving force to a unit that can be attached to and detached from the main body of the device, and an image forming device including the drive transmission device.

In recent years, in image forming devices such as electrophotographic printers and copiers, miniaturization and improvement in operability have been desired.

From the viewpoint of improving the operability of the image forming apparatus, a process cartridge method is adopted in which the photoconductor, charging means, developing means, cleaning means, etc. are integrated into a cartridge, and this cartridge can be attached to and detached from the image forming apparatus main body. ing. This cartridge method further improves operability and enables the user to easily perform maintenance of the above-mentioned process means such as development.

Similarly, the intermediate transfer body of the image forming apparatus main body is also formed as a unit and can be attached to and detached from the image forming apparatus main body to improve operability and maintainability.

Further, as a drive transmission device that stably and reliably transmits the 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 corresponding concave portion is performed. Couplings are used.

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

Japanese Unexamined Patent Publication No. 2005-157112

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

For example, when a link mechanism is provided on the opening / closing cover in order to connect / disconnect the coupling, the coupling is released / connected each time the cover is opened / closed, and the coupling is released / connected which is not originally necessary. The cover will bear the load of. In any case, a load such as a resistor 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 lined up, the load for releasing and connecting the couplings becomes large, and therefore, the operability of opening and closing the cover is deteriorated.

Further, the link mechanism is required to have high rigidity. Furthermore, the link mechanism itself becomes large and the rigidity of the cover needs to be increased, which has led to an increase in the size and cost of the device.

The unit of the present invention for solving the above problems has a rotation axis of the first coupling with respect to the apparatus main body of the electrophotographic image forming apparatus having the first protrusion and the rotatable first coupling. A unit that is removable along a substantially orthogonal detachment direction and has a second coupling that meshes with and rotates with the first coupling, the second coupling engaging with the first protrusion. The apparatus main body is provided with a matching second protrusion, and at least one of the first coupling and the second coupling is provided with an inclined surface inclined with respect to the rotation axis of the first coupling. When the unit is pulled out from the unit in the detaching direction, the second coupling has a structure capable of moving in the detaching direction with respect to the first coupling, and the first coupling and the first coupling. The step provided in at least one of the first coupling and the second coupling in the process of moving the second coupling from the engaged state of the second coupling in the detaching direction. When the other comes into contact with the inclined surface, the second coupling starts retracting in a direction parallel to the rotation axis of the first coupling relative to the first coupling. And.

According to the present invention, the coupling, which is a drive transmission device, is automatically connected / disconnected from the main body of the device to the detachable unit as the unit is attached / detached.

It is sectional drawing which shows the main part of the image forming apparatus which concerns on Embodiment 1 of this 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 main part of the drive transmission device 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. It is a schematic diagram which shows the state of the drive coupling and the driven coupling before the intermediate transfer unit which concerns on Embodiment 1 of this invention starts detachment. It is a schematic diagram which shows the state which the contact between the 1st engaging part and the 2nd engaging part which concerns on Embodiment 1 of this invention is released. It is the schematic which shows the distance between the rotation shaft of the drive coupling and the rotation shaft of the driven coupling which concerns on Embodiment 1 of this invention. It is a schematic perspective view which shows the transfer separation means which concerns on Embodiment 1 of this invention (phase G). It is a schematic perspective view which shows the transfer separation means which concerns on 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. It is the schematic which shows the state of the drive coupling and the driven coupling before the intermediate transfer unit which concerns on Embodiment 2 of this invention starts detachment. It is a schematic diagram which shows the state which the contact between the 1st engaging part and the 2nd engaging part which concerns on Embodiment 2 of this invention is released. It is the schematic which shows the distance between the rotation shaft of the drive coupling and the rotation shaft of the driven coupling which concerns on Embodiment 2 of this invention. 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. It is a schematic diagram which shows the state of the drive coupling and the driven coupling before the intermediate transfer unit which concerns on Embodiment 3 of this invention starts detachment. It is a schematic diagram which shows the state which the contact between the 1st engaging part and the 2nd engaging part which concerns on Embodiment 3 of this invention is released. It is the schematic which shows the distance between the rotation shaft of the drive coupling and the rotation shaft of the driven coupling which concerns on Embodiment 3 of this invention. 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 / detachment direction of a process cartridge. It is a top view which shows the attachment / detachment direction of a process cartridge. It is a perspective view which shows the main part of the drive transmission device in the background art.

(Embodiment 1)
This embodiment will be described by using an electrophotographic quadruple drum type color image forming apparatus as the main body of the apparatus and using an intermediate transfer unit as a detachable unit. Further, in the present embodiment, a drive transmission device is used in order to transmit a driving force for separating the primary transfer roller in the intermediate transfer unit from the corresponding photosensitive drum from the device main body. The drive transmission device of the present embodiment has a first coupling and a second coupling that meshes with and rotates 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. 1 to 12.

[Image forming device]
First, the configuration of the apparatus main 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 a photosensitive drum 1 which is a photoconductor, a charging roller 2 which is a charging unit, an exposure unit 3, a developing unit 4, and the like. The apparatus main body 100 includes four photosensitive drums 1a, 1b, 1c, and 1d. Around each photosensitive drum 1, a charging roller 2 (2a, 2b, 2c, 2d) that uniformly charges the surface of the photosensitive drum 1 is irradiated with a laser based on image information in order according to the rotation direction of the photosensitive drum 1. There is an exposure unit 3 that forms an electrostatic latent image on the 1. Further, the developing unit 4 (4a, 4b, 4c, 4d) that adheres toner to the electrostatic latent image on the photosensitive drum 1 and visualizes it as a toner image, and the toner image on the photosensitive drum 1 is transferred to the intermediate transfer belt 12e. There are transfer means 12a, 12b, 12c, 12d to be used. Further, cleaning means 8 (8a, 8b, 8c, 8d) for removing the post-transcription toner remaining on the surface of the photosensitive drum 1 after transfer is provided.

The photosensitive drum 1, the charging roller 2, the developing unit 4, and the cleaning means 8 (8a, 8b, 8c, 8d) are integrated into a cartridge to form a process cartridge 7 (7a, 7b, 7c, 7d). Each process cartridge is detachably configured to be attached to and detached from the device main body 100. These four process cartridges 7a, 7b, 7c, and 7d have the same structure, but use yellow (Y), magenta (M), cyan (C), and black (Bk) toners to form images of different colors. It is different in that it does.

The process cartridges 7a, 7b, 7c, and 7d are composed of developing units 4a, 4b, 4c, and 4d and cleaning units 5a, 5b, 5c, and 5d. Of these, the former developing units 4a, 4b, 4c, and 4d have developing rollers 24a, 24b, 24c, 24d, developer coating rollers 25a, 25b, 25c, 25d, and a toner container. The latter cleaning unit 5a, 5b, 5c, 5d includes photosensitive drums 1a, 1b, 1c, 1d, charging rollers 2a, 2b, 2c, 2d, cleaning means 8a, 8b, 8c, 8d, and a transfer residual toner container. doing.

The photosensitive drums 1a, 1b, 1c, and 1d are formed by applying an organic optical transmitter 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 drive motor (not shown) to one end of the photosensitive drums 1a, 1b, 1c, and 1d, the drums are rotationally driven in the clockwise direction shown by the arrow in FIG.

The charging rollers 2a, 2b, 2c, and 2d are conductive rollers formed in a roller shape. The 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 exposes the photosensitive drums 1a, 1b, 1c, and 1d based on the image signal.

The toner container contains toner of each color of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively.

The developing rollers 24a, 24b, 24c, and 24d are arranged adjacent to the surfaces of the photosensitive drums 1a, 1b, 1c, and 1d, and are rotationally driven by a driving unit (not shown) and by applying a voltage. The surface of the photosensitive drums 1a, 1b, 1c, and 1d is developed.

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 primarily transferred to the surface of the intermediate transfer belt 12e. After that, 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 The transfer of the toner image to 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 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 on the downstream side of the secondary transfer unit 15 and fixes the toner image transferred to the transfer material on the transfer material S.

The paper feed device 13 is mainly composed of a paper feed cassette 11 for storing the transfer material S, a paper feed roller 9, a separation means 23, and a resist roller pair 10 for sandwiching and transporting the transfer material S. The fixing device 14 is composed of a fixing film 14a, a pressure roller 14b, a heating body 14c, and a paper ejection roller pair 20.

The paper cassette 11 can be pulled out toward the front of the device body (on the left side of the device 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 paper 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 materials S are separated one by one by the separating means 23. Separated and fed. After that, the transfer material S is transferred to the secondary transfer unit 15 by the resist roller pair 10.

In the secondary transfer unit 15, a bias is applied to the secondary transfer means 16, and the toner image on the intermediate transfer belt 12e is transferred onto the transfer material S that has been 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 arranged on the toner image surface side on the transfer material S. The heating body 14c is arranged 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), 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 sandwiched and conveyed between the fixing film 14a and the pressure roller 14b, and the toner image is heat-fixed on the transfer material S. The transfer material S on which the toner image is fixed is then sandwiched and conveyed by the paper ejection rollers to 20, and is ejected onto the paper ejection 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 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, 12d which are primary transfer means, cleaning means 22, and primary transfer separation. It is composed of means 30. The intermediate transfer belt 12e is stretched on the driving roller 12f and the driven roller 12g. The driven roller 12g is urged by the urging means in the E direction 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 shown by the arrow in FIG.

The primary transfer rollers 12a, 12b, 12c, and 12d are arranged inside the intermediate transfer belt 12e so as to face the photosensitive drums 1a, 1b, 1c, and 1d, and are arranged on the photosensitive drum 1 side by the urging member 31. Is being urged 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. Toner images of four colors are superimposed and transferred on the intermediate transfer belt, and the toner image on the intermediate transfer belt 12 is 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 means 22, and the toner recovery container (not shown) arranged in the apparatus main body 100 passes through the transfer residual toner transfer path (not shown). Collected in (shown).

The intermediate transfer unit 12 has a separation configuration of primary transfer rollers corresponding to Y, M, and C that are in contact with the photosensitive drum 1 via the intermediate transfer belt 12e when forming a color image. 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.
9 and 10 show an example of the primary transfer separation means 30 in the present embodiment.

The primary transfer separating means 30 is mainly composed of a cam shaft 32, slide members 33a and 33b, and cam members 34a and 34b. Cam members 34a and 34b having a target shape are arranged at both ends of the cam shaft 32, and slide members 33a and 33b are arranged at both ends of the primary transfer rollers 12a, 12b and 12c. By moving the slide member left and right, it is possible to change the positions of the primary transfer rollers 12a, 12b, and 12c with respect to the photosensitive drums 1a, 1b, and 1c.

At the time of 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 state. As a result, the primary transfer rollers 12a, 12b, 12c, and 12d come into contact with 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 C direction shown in the drawing. Therefore, the slide members 33a and 33b move in the D direction shown in the drawing. .. At the time of forming the mono image, 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 state. Then, the primary transfer rollers 12a, 12b, 12c corresponding to Y, M, and C are moved and held by the slide members 33a, 33b to the positions retracted from the photosensitive drums 1a, 1b, and 1c against the urging direction, and are exposed to light. Separated from the drums 1a, 1b, 1c. Further, when the cam members 34a and 34b rotate in the C direction shown in the drawing, the state returns to the phase G state, and the slide members 33a and 33b also enter the position J state.

[Drive transmission device]
The drive transmission device 40 according to 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 a coupling provided in the main body of the apparatus and rotated by power from a drive source. The second coupling is a coupling that is provided on the unit and that meshes with and rotates with the first coupling.

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

The apparatus main body 100 is provided with a first coupling, a drive coupling 41, 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 second coupling, a driven coupling 42, an urging member 45, and a transmission gear row 44b. As shown in FIG. 4, the urging member 45 is a spring and urges the urging member 45 in the B direction, that is, toward the device main body side. The driven coupling 42 is arranged at a position facing the drive coupling 41 with the intermediate transfer unit 12 mounted on the apparatus main body 100. The driven coupling 42, which is the second coupling, can rotate by engaging with the drive coupling 41, which is the first coupling.

The guide member 46 is arranged on the main body of the apparatus so that the driven coupling 42 comes into contact with the intermediate transfer unit 12 when the intermediate transfer unit 12 is attached or detached. Further, a slope 46a for retracting the driven coupling 42 in the M direction shown in the drawing is provided on the inlet side when the intermediate transfer unit 12 is mounted on the apparatus main body 100.

As shown in FIG. 4, the transmission gear 44a is arranged so as to connect the drive motor 43 and the drive coupling 41, and the transmission gear row 44b connects the driven coupling 42 and the cam shaft 32. It is arranged so as to.

As shown in FIG. 5, the drive coupling 41 provided in the apparatus main body has a concave shape. Further, the driven coupling 42 has a convex shape that fits into the concave coupling. However, the drive transmission device of 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. It may be in shape.

The drive coupling has a T-shaped first engaging portion 41b. Further, the concave drive coupling 41 has an inclined surface 41e on the inner peripheral portion. The driven coupling 42 having a convex shape has a second engaging portion 42a as a convex portion. When the drive coupling 41 and the driven coupling 42 are in mesh with each other, the second engaging 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 in mesh with each other, the first engaging 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 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 when the intermediate transfer unit 12 is mounted on the main body, the inclined surface 41e is in contact with the second engaging portion 42a of the driven coupling 42. Contact. As shown in FIG. 3, the driven coupling 42 is urged by the urging member 45 toward the drive coupling 41 in the B direction, which is substantially vertical to the A direction, which is the attachment / detachment direction of the unit. .. The B direction is parallel to the axis of rotation 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, as the drive coupling 41 rotates, the contact surface 41c of the first engaging portion 41b meshes with the contact surface 42c of the second engaging portion. That is, the contact surface 41c of the first engaging portion of the drive coupling 41 to which the driving force is transmitted by the drive motor presses the contact surface 42c portion of the second engaging 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 shown in the drawing. At this time, the 41c and 42c portions that transmit the rotational drive are shaped to transmit the force in the rotational direction. Since the contact surfaces 41c and 42c are engaged with each other on an axis substantially perpendicular to the rotation direction L, the force pushing the driven coupling 42 in the rotation axis direction against the urging direction B direction during rotation is Does not occur.

Next, a case where the intermediate transfer unit 12 is pulled out (separated) from the apparatus main body 100 will be described. When the drive coupling 41 and the driven coupling 42 are engaged, the second engaging 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 from the apparatus main body 100, when a force acting in the detaching direction (pulling force) of the intermediate transfer unit 12 acts, the inclined surface 41e causes the driven coupling 42 to be urged in the urging direction B. A force acts to move in the reverse direction of the illustrated M. Then, the driven coupling 42 is temporarily retracted from the drive coupling 41 in the M direction shown in the drawing. As a result, the engagement between the first engaging portion 41b and the second engaging portion 42a is released. Further, since the driven coupling 42 comes into contact with the guide member 46 and continues to retract in the illustrated M direction opposite to the urging direction B, the intermediate transfer unit 12 can be pulled out 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 disengage, and FIG. 7 shows the engagement between the first engaging portion 41b and the second engaging portion 42a being disengaged. Each state is shown.

6 and 7A are perspective views showing the states of the drive coupling 41 and the driven coupling 42, and FIG. 7B is a rotation axis showing the states of the drive coupling 41 and the driven coupling 42. It is a schematic view seen from the direction perpendicular to. 6 and 7 (c) are schematic views of the states of the drive coupling 41 and the driven coupling 42 viewed from a 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 disengagement direction in the second engaging portion 42a. The contact surface 41c between the joint portion (shown by 42f in FIG. 6, hereinafter referred to as the second engaging portion 42f) and the first engaging portion 41b of the drive coupling is configured to have a sufficient gap in the rotation direction. It is done.

When the unit is pulled out from the main body of the apparatus in a direction perpendicular to the rotation axis of the drive coupling 41, the force acting in the disengagement 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 has a position different from the rotation axis of the drive coupling 41 and the position where 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 the second engaging portion. It is set to 42h. In the present 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 rotating about the position k, the second engaging portion 42f approaches the contact surface 41c of the first engaging portion, so that the contact surface with the second engaging portion 42f The gap between 41c is reduced. When the driven coupling 42 rotates, the second engaging portion of the driven coupling located on the most downstream side in the intermediate transfer unit disengagement direction in the second engaging portion 42a (42 g in FIG. 7). (Hereinafter, the second engaging portion 42 g) moves along the inclined surface 41e of the drive coupling in the disengagement direction of the intermediate transfer unit. When the second engaging portion 42g moves along the inclined surface 41e, the driven coupling 42 retracts in the M direction in the figure. As a result, as shown in FIG. 7, the engagement between the first engaging portion and the second engaging 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 axis of the driven coupling 42 with respect to the rotation axis of the drive coupling 41 until the engagement between the second engagement portion 42a and the first engagement portion 41b is disengaged. The distance to move in the unit detachment direction is β.

Next, when the unit is pulled out from the main body of the device in the direction perpendicular to the rotation axis of the drive coupling 41, the rotation axis of the driven coupling 42 is moved by the force acting in the detachment direction of the unit. A structure that can move in the unit detachment direction from the rotation axis will be described. As can be seen from FIG. 5, the driven coupling 42 has a sufficiently large area in which the drive 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 rotation axis of the driven coupling 42 can move with respect to the rotation axis of the drive coupling 41 in the unit detachment direction 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 about the position k, the driven coupling is performed before the second engaging portion 42f comes into contact with the first engaging portion 41b. The evacuation of 42 in the M direction is completed.

That is, in the coupling configuration of the present embodiment, the engagement between the driven coupling 42 and the drive coupling 41 is released only by pulling out the intermediate transfer unit 12 from the apparatus main body 100, and the first engaging portion 41b and the first engaging portion 41b are disengaged. The engagement of the engaging portion 42a of 2 is released.

Contrary to the above, when the intermediate transfer unit 12 is attached to the image forming apparatus 100 main body, the driven coupling 42 comes into contact with the guide member 46 of the apparatus main body 100, so that the intermediate transfer unit 12 is retracted in the M direction shown in the drawing. As a result, the driven coupling 42 can smoothly move to the meshing position with the drive coupling 41. Then, in a state where the rotation axis of the driven coupling 42 and the rotation axis of the drive coupling 41 are substantially the same, as described above, when the rotation phases of the couplings match, the couplings mesh with each other and the intermediate transfer unit 12 Is completed on the device body 100.

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 with each other 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 have a configuration in which one of the outer peripheral portion of the convex coupling and the inner peripheral portion of the concave coupling has an inclined surface 41e. Further, 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. , It may be configured to have inclined surfaces on both sides. If an inclined surface is provided on both the drive coupling 41 and the driven coupling 42, the driven coupling 42 can be more smoothly retracted in the illustrated M direction opposite to the urging 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 to. Further, in the case of the phase shown in FIG. 12B, the driven coupling 42 does not rotate around the contact position between the second engaging portion 42a and the first engaging portion 41b. , The unit can be retracted in the M direction along the inclined surface by the force acting in the detaching direction of the unit.

(Embodiment 2)
In the present embodiment, a drive transmission device in which the drive coupling 51 and the driven coupling 52 mesh with each other in a plurality of phases will be described. The configurations other than the drive transmission device are all the same as those in the first embodiment.

When it is not necessary to control the phase of 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 rollers on the unit side in a predetermined direction and speed corresponds to this.

51 in FIG. 13 is a driven 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 drive coupling 51 are different from those of the coupling rig of the first embodiment.

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

Further, as shown in FIG. 16, similarly to the first embodiment, the maximum distance that the rotating shaft of the driven coupling 52 can move in the unit detaching direction with respect to the rotating shaft of the driving coupling 51 is α. When α is β or more, when the driven coupling 52 rotates about the position k, the driven coupling is performed before the second engaging portion 52f comes into contact with the first engaging portion 51b. Evacuation of 52 in the M direction is completed.

Further, as shown in FIG. 17, the second engaging portion 52a of the driven coupling 52 may also have an inclined surface 51e. When both the driven coupling 51 and the driven coupling 52 are provided with inclined surfaces, the driven coupling 52 can be more smoothly retracted in the illustrated M direction opposite to the urging direction B.

(Embodiment 3)
In the present embodiment, a drive transmission device in which the drive coupling 61 and the driven coupling 62 mesh with each other in a plurality of phases will be described. The configurations other than the drive transmission device are all the same as those in the first embodiment. Similar to 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.

61 in FIG. 18 is a driven 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 drive coupling 62 are different from those of the coupling rig of the first embodiment.

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

Further, as shown in FIG. 21, as in the first embodiment, the maximum distance that the rotating shaft of the driven coupling 62 can move in the unit detaching direction with respect to the rotating shaft of the driving coupling 61 is α. When α is β or more, the driven coupling rig 62 can be smoothly retracted from the driving coupling 61.

Further, as shown in FIG. 22, the second engaging portion 62a of the driven coupling 62 may also have an inclined surface 61e. If an inclined surface is provided on both the drive coupling 61 and the driven coupling 62, the driven coupling 62 can be more smoothly retracted in the illustrated M direction opposite to the urging direction B.

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

The driven coupling 42 is urged toward the drive coupling 41 by the urging member 45, and the arc surface 42i comes into contact with the inclined surface 41e of the drive coupling 41 in the axial direction of the driven coupling 42. The structure is such that the position is determined.

Here, even if the position of the mounted intermediate transfer unit 12 is displaced within the range of variation with respect to the apparatus main body 100, even if there is some eccentricity due to the positional deviation by this configuration, the rotation is performed. Can transmit power.

(Other embodiments)
In the above embodiment, an example in which a coupling is used as a drive transmission device between the intermediate transfer unit 12 and the apparatus main body is shown as a unit, but it can also be applied to other units and couplings. For example, it is between the coupling between the developing unit (cartridge) and the main body of the apparatus, or between the process cartridge 7 of the first embodiment and the main body of the apparatus. 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 carry out even if these relationships are reversed. Further, regardless of which coupling is retracted when the unit is attached to the main body of the apparatus or the like, the function related to the engagement of the drive coupling 41 and the driven coupling 42 is similarly exhibited.

1 Photosensitive drum 2 Charging roller 3 Exposure means 4 Development unit 4a to 4d Development unit 5a to 5d Cleaning unit 7 Process cartridge 8 Cleaning means 9 Paper feed roller 10 Resist roller vs. 11 Paper cassette 12 Intermediate transfer unit 12a to 12d (primary) Transfer means 12e Intermediate transfer belt (intermediate transfer material)
12f Drive roller 12g Driven roller 13 Feeding device 14 Fixing device 15 Secondary transfer unit 16 Secondary transfer means 20 Paper discharge roller vs. 22 Cleaning means 23 Separation means 24a to 24d Development roller 25a to 25d Developer coating roller 30 Primary transfer separation Means 31 Biasing member 32 Camshaft 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 Bounce member 100 Image forming device S Transfer material A, B, C, D, E, F, L, M direction G, H phase J, K position

Claims (10)

A unit that is removable along a detachment direction substantially orthogonal to the rotation axis of the first coupling with respect to the main body of the electrophotographic image forming apparatus having the first protrusion and the rotatable first coupling. There,
It has a second coupling that rotates in mesh with the first coupling.
The second coupling comprises a second protrusion that engages with the first protrusion.
At least one of the first coupling and the second coupling has an inclined surface inclined with respect to the rotation axis of the first coupling.
When the unit is pulled out from the apparatus main body in the detaching direction, the second coupling has a structure capable of moving in the detaching direction with respect to the first coupling.
Of the first coupling and the second coupling, in the process of moving the second coupling in the detaching direction from the state where the first coupling and the second coupling are engaged. When the other comes into contact with the inclined surface provided on at least one of the above, the direction in which the second coupling is relatively parallel to the rotation axis of the first coupling with respect to the first coupling. A unit characterized by starting evacuation to. When the unit is pulled out from the apparatus main body in the detachment direction, at least one of the first coupling and the second coupling is rotatable by a force acting in the detachment direction. The unit according to claim 1. The unit is characterized by comprising a spring that urges the second coupling in a direction parallel to the rotation axis of the first coupling and in a direction toward the first coupling. The unit according to 1 or 2. 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. The unit described in paragraph 1. The unit according to any one of claims 1 to 3, wherein the unit includes a photosensitive drum. The second coupling is provided with a plane intersecting the rotation axis of the second coupling, and the second protrusion protrudes from the plane in a direction parallel to the rotation axis of the second coupling. The unit according to any one of claims 1 to 5, wherein the unit has a shape. The unit according to any one of claims 1 to 5, wherein the second protrusion is a protrusion extending in a direction parallel to the rotation axis of the second coupling. The second coupling comprises another second protrusion, and when the second coupling is engaged with the first coupling, the second protrusion and the other second protrusion. The unit according to any one of claims 1 to 7, wherein a part of the first coupling has entered the space between the two. The unit according to claim 8, wherein the inclined surface is formed on the other second protrusion. The unit according to any one of claims 1 to 9, wherein the inclined surface is formed on the second protrusion.

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