JP2020101840A - Drive transmission device and image forming apparatus - Google Patents

Abstract

To improve operability when a unit is inserted/removed.SOLUTION: A unit attachable to/detachable from an apparatus body includes a coupling for receiving rotary drive from the apparatus body. The apparatus body also includes a coupling engaged with the coupling of the unit. At least one of the couplings can be pressed in a direction parallel to a rotary shaft and one of the couplings includes a slope. When attaching/detaching the unit, one coupling is pushed by the slope and pressed on, thereby disengaging the couplings.SELECTED DRAWING: Figure 7

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 an apparatus main body, and an image forming apparatus including the drive transmission device.

In recent years, in image forming apparatuses such as electrophotographic printers and copying machines, there is a demand for downsizing and improvement of operability.

From the viewpoint of improving the operability of the image forming apparatus, a process cartridge system is adopted in which a photosensitive member, a charging unit, a developing unit, a cleaning unit, and the like are integrated into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. ing. With this cartridge system, the operability is further improved, and the user himself/herself can easily perform maintenance of the above-mentioned process means such as development.

Similarly, the intermediate transfer member of the main body of the image forming apparatus has a unit structure and can be attached to and detached from the main body of the image forming apparatus to improve operability and maintainability.

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

In Patent Document 1, the coupling pair is interlocked with a cover that opens and closes, and the operation of opening the cover causes the coupling on the apparatus body side to retract from the coupling on the unit side, so that the coupling pair is disconnected. A configuration that allows 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/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 of the cover. Due to this mechanism, the operability of opening and closing the cover is deteriorated, and the cost is increased due to the complicated structure.

For example, if a link mechanism is provided on the opening/closing cover to connect and disconnect the coupling, the coupling is released and connected each time the cover is opened and closed, and the coupling is released and connected that is not originally necessary. The cover will bear the load. In that case, a load such as a resistance required for releasing and connecting the coupling is added to the operation force for opening and closing the cover. In particular, in a color image forming apparatus in which four process cartridges are arranged side by side, the load for releasing and connecting the coupling also becomes large, which deteriorates the operability of opening and closing the cover.

Further, the link mechanism is required to have high rigidity. Furthermore, since the link mechanism itself becomes large and the cover needs to have increased rigidity, it leads to an increase in size and cost of the device.

An image forming apparatus of the present invention for solving the above-mentioned problems includes an apparatus main body, a unit detachable from the apparatus main body, and a first coupling that is provided in the apparatus main body and is rotated by power from a drive source. And a second coupling that is provided in the unit and that rotates by meshing with the first coupling,
One of the first coupling and the second coupling has a concave shape, and the other coupling has a convex shape that fits into the one coupling. At least one of the outer peripheral portion of the ring and the inner peripheral portion of the concave coupling has an inclined surface, and at least one of the first coupling and the second coupling is parallel to the rotation axis. The second coupling by a force acting in the detaching direction of the unit when pulling out the unit from the apparatus main body in a direction perpendicular to the rotation axis of the first coupling. Has a structure in which the rotation shaft of the first coupling is movable in the unit detaching direction with respect to the rotation shaft of the first coupling, and the rotation of the rotation shaft causes the first coupling and the second coupling to move. At least one of the two is retracted along the inclined surface in a direction parallel to the rotation axis.

In addition, a drive transmission device of the present invention for solving the above-mentioned problems is attachable to and detachable from a first coupling that rotates by power from a drive source, and the first coupling. A second coupling that rotates in mesh with the ring,
One of the first coupling and the second coupling has a concave shape, and the other coupling has a convex shape that fits into the one coupling. At least one of the outer peripheral portion of the ring and the inner peripheral portion of the concave coupling has an inclined surface, and at least one of the first coupling and the second coupling is parallel to the rotation axis. Is retractable in a direction, and the second coupling is pulled out in a direction perpendicular to the rotation axis of the first coupling from a state in which the first coupling and the second coupling are engaged with each other. At this time, the rotation shaft of the second coupling is movable in the unit separation direction more than the rotation shaft of the first coupling by the force acting in the separation direction of the second coupling. At least one of the first coupling and the second coupling is retracted in the direction parallel to the rotation axis along the inclined surface by the movement of the rotation axis.

According to the present invention, coupling/uncoupling of the coupling, which is a drive transmission device, from the apparatus body to the detachable unit is automatically performed in association with the mounting/dismounting action of the unit.

FIG. 3 is a sectional view showing a main part of the image forming apparatus according to the first embodiment 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. FIG. 3 is a perspective view showing a main part of the drive transmission device according to the first embodiment of the present invention. It is a perspective view which shows the coupling which concerns on Embodiment 1 of this invention. FIG. 3 is a schematic diagram showing a state of a driving coupling and a driven coupling before the intermediate transfer unit according to the first embodiment of the present invention starts to separate. FIG. 3 is a schematic diagram showing a state in which the contact between the first engagement portion and the second engagement portion according to Embodiment 1 of the present invention is released. FIG. 3 is a schematic diagram showing a distance between a rotary shaft of a drive coupling and a rotary shaft of a driven coupling according to the first embodiment of the present invention. FIG. 3 is a schematic perspective view showing a transfer separating unit according to the first embodiment of the present invention (phase G). FIG. 3 is a schematic perspective view showing a transfer separating unit according to the first embodiment of the present invention (phase H). It is a perspective view which shows the other coupling which concerns on Embodiment 1 of this invention. FIG. 6 is a plan view showing another phase of the coupling according to the first embodiment of the present invention. It is a perspective view which shows the coupling which concerns on Embodiment 2 of this invention. FIG. 6 is a schematic diagram showing a state of a driving coupling and a driven coupling before the intermediate transfer unit according to the second embodiment of the present invention starts to separate. It is a schematic diagram showing the state where the contact between the 1st engaging part and the 2nd engaging part concerning Embodiment 2 of the present invention was canceled. FIG. 6 is a schematic diagram showing a distance between a rotation shaft of a drive coupling and a rotation shaft of a driven coupling according to Embodiment 2 of the present 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. FIG. 11 is a schematic diagram showing a state of a driving coupling and a driven coupling before the start of separation of the intermediate transfer unit according to the third embodiment of the present invention. It is a schematic diagram showing the state where contact between the 1st engaging part and the 2nd engaging part concerning Embodiment 3 of the present invention was canceled. FIG. 7 is a schematic diagram showing a distance between a rotation shaft of a drive coupling and a rotation shaft of a driven coupling according to a third embodiment of the present 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. FIG. 6 is a perspective view showing a mounting and demounting direction of a process cartridge. FIG. 6 is a plan view showing a mounting and demounting 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)
This embodiment will be described by using an electrophotographic 4-drum color image forming apparatus as the apparatus main body and an intermediate transfer unit as a detachable unit. Further, in the present embodiment, the drive transmission device is used in order 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 by meshing with the first coupling.

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

[Image forming device]
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 A toner image is formed by the photosensitive drum 1, which is a photoconductor, the charging roller 2, which is 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) that uniformly charge the surface of the photosensitive drums 1 in order in accordance with the rotation direction thereof, and a photosensitive drum that is irradiated with laser based on image information. There is an exposure unit 3 on which an electrostatic latent image is formed. Further, the developing unit 4 (4a, 4b, 4c, 4d) that attaches toner to the electrostatic latent image on the photosensitive drum 1 to visualize it as a toner image, 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 post-transfer 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 integrally made into a cartridge to form a process cartridge 7 (7a, 7b, 7c, 7d). Each of the process cartridges is detachably attached to the apparatus main body 100. These four process cartridges 7a, 7b, 7c, and 7d have the same structure, but images of different colors are formed using yellow (Y), magenta (M), cyan (C), and black (Bk) toners. The difference is that

The process cartridges 7a, 7b, 7c, 7d are composed of developing units 4a, 4b, 4c, 4d and cleaning units 5a, 5b, 5c, 5d. Of these, the former developing units 4a, 4b, 4c, 4d have developing rollers 24a, 24b, 24c, 24d, developer applying rollers 25a, 25b, 25c, 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. doing.

The photosensitive drums 1a, 1b, 1c, 1d are formed by applying an organic photoconductor 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 the clockwise direction indicated by the arrow in FIG.

The charging rollers 2a, 2b, 2c, 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, 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, 1d. The exposure unit 3 is arranged vertically below the process cartridge 7 (7a, 7b, 7c, 7d) and performs exposure based on an image signal to the photosensitive drums 1a, 1b, 1c, 1d.

The toner containers contain toners of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively.

The developing rollers 24a, 24b, 24c, 24d are arranged adjacent to the surfaces of the photosensitive drums 1a, 1b, 1c, 1d, and are driven to rotate by a driving unit (not shown), and by applying a voltage, The surface of the photosensitive drum 1a, 1b, 1c, 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, 1d are sequentially primary-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, 1d is removed by the cleaning means 8a, 8b, 8c, 8d and collected in the transfer material toner container in the cleaning units 5a, 5b, 5c, 5d. ..

(2) Transfer to Transfer Material and Fixing Process The transfer of the toner image to the transfer material S is carried out by the paper feeding device 13 to the secondary transfer section 15 where the transfer material is conveyed to the secondary transfer section 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 on the transfer material onto the transfer material S.

The sheet feeding device 13 mainly includes a sheet feeding cassette 11 that stores the transfer material S, a sheet feeding roller 9, a separating unit 23, and a registration roller pair 10 that sandwiches and conveys the transfer material S. The fixing device 14 includes a fixing film 14a, a pressure roller 14b, a heating body 14c, and a paper discharge roller pair 20.

The paper feed cassette 11 can be pulled out in the front direction of the apparatus body (left side of the apparatus 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 it 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 to send out the transfer material S, and the transfer material S is separated by the separating means 23 one by one. Separated and fed. After that, 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 12 e 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 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 unit (not shown), the fixing film 14a is rotated accordingly, and the heating body 14c heats the fixing film 14a. The transfer material S conveyed from the secondary transfer portion 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. The transfer material S on which the toner image has been fixed is then nipped and conveyed by the paper discharge roller pair 20 and discharged onto the paper 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 attachable to and 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 which are primary transfer means, a cleaning means 22, a primary transfer separation. It is composed of means 30. The intermediate transfer belt 12e is stretched around a driving roller 12f and a driven roller 12g. The driven roller 12g is biased by the biasing means in the E direction indicated 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.

Each of the primary transfer rollers 12a, 12b, 12c, 12d is arranged inside the intermediate transfer belt 12e so as to face each of the photosensitive drums 1a, 1b, 1c, 1d, and is biased by the biasing member 31 toward the photosensitive drum 1 side. Is urged to. By applying a voltage to the primary transfer rollers 12a, 12b, 12c, 12d, the toner images formed on the surfaces of the photosensitive drums 1a, 1b, 1c, 1d are primarily transferred onto the intermediate transfer belt 12e. Toner images of four colors are superposedly transferred onto the intermediate transfer belt, 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, passes through the transfer residual toner carrying path (not shown), and is transferred to the toner collecting container (not shown) provided in the apparatus main body 100. (Shown).

The intermediate transfer unit 12 has a structure in which primary transfer rollers corresponding to Y, M, and C that are in contact with the photosensitive drum 1 via the intermediate transfer belt 12e at the time of color image formation are separated. This is for suppressing the rubbing against the photosensitive drum 1 which is not used at the time of mono image formation and for prolonging the life of the photosensitive drum 1.
9 and 10 show an example of the primary transfer separating means 30 according to 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. Cam members 34a and 34b having a symmetrical 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. The position of the primary transfer rollers 12a, 12b, 12c with respect to the photosensitive drums 1a, 1b, 1c can be changed by moving the slide member 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, 12d come into contact with the photosensitive drums 1a, 1b, 1c, 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 in the figure, so that the slide members 33a and 33b move in the D direction 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 state. Then, the primary transfer rollers 12a, 12b, 12c corresponding to Y, M, C are moved and held by the slide members 33a, 33b to positions retracted from the photosensitive drums 1a, 1b, 1c against the biasing direction. Separated from the drums 1a, 1b, 1c. When the cam members 34a and 34b further rotate in the direction C in the figure, the state returns to the state of the phase G, and the slide members 33a and 33b also reach the position J.

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

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

The device 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 that is a second coupling, an urging member 45, and a transmission gear train 44b. As shown in FIG. 4, the urging member 45 is a spring and urges in the B direction, that is, toward the apparatus main body side. The driven coupling 42 is arranged at a position facing the driving coupling 41 when 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 engaging with the driving coupling 41 that is the first coupling.

The guide member 46 is arranged in the apparatus main body so that the driven coupling 42 comes into contact when the intermediate transfer unit 12 is attached or detached. Further, an inclined surface 46a for retracting the driven coupling 42 in the M direction 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 to connect the drive motor 43 and the drive coupling 41, and the transmission gear train 44b connects the driven coupling 42 and the cam shaft 32. It is arranged as follows.

As shown in FIG. 5, the drive coupling 41 provided in the apparatus body has a concave shape. Further, the driven coupling 42 has a convex shape that fits into a concave coupling. However, the drive transmission device of the present embodiment is not limited to the above configuration, and one of the driving coupling 41 and the driven coupling 42 has a concave shape and the other coupling has a convex shape. Any shape will do.

The drive coupling has a T-shaped first engaging portion 41b. Further, the drive coupling 41 having a concave shape 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. In the state where the drive coupling 41 and the driven coupling 42 are in mesh 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 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 be engaged 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 contacts the second engaging portion 42a of the driven coupling 42 when the intermediate transfer unit 12 is mounted on the main body. Contact. 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, which is a direction substantially perpendicular to the A direction, which is the attachment/detachment direction of the unit. .. The B direction is parallel to the axes 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 in the figure. 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 engagement 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 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, the portions 41c and 42c for transmitting 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 by an axis line that is 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, is generated during rotation. Does not occur.

Next, a 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 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 the force acting in the detaching direction of the intermediate transfer unit 12 (pulling force) acts, the inclined surface 41e causes the driven coupling 42 to move in the biasing direction B. Has a force to move in the reverse direction M in the figure. Then, the driven coupling 42 is temporarily retracted from the driving coupling 41 in the M direction 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 contacts the guide member 46 and continues to retract in the M direction shown in the drawing, which is 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 driving coupling and the driven coupling before the intermediate transfer unit starts to be disengaged, and FIG. 7 shows the disengagement of the first engaging portion 41b and the second engaging portion 42a. Each state is shown.

6 and 7 are perspective views showing the states of the driving coupling 41 and the driven coupling 42, and FIG. 6B shows the states of the driving coupling 41 and the driven coupling 42 as the rotating shaft. It is a schematic diagram seen from the direction perpendicular to. 6 and 7(c) are schematic views of the states of the driving coupling 41 and the driven coupling 42 as seen from a direction parallel to the rotation axis.

Before the intermediate transfer unit is disengaged, as shown in FIG. 6B, the second engagement portion of the driven coupling, which is located on the most upstream side in the intermediate transfer unit disengagement direction in the second engaging portion 42a. The contact surface 41c of the coupling portion (indicated 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 gap in the rotational direction. I am doing it.

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 force acting in the detaching 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 pivoted at a position different from the rotation axis of the drive coupling 41 and at a position where the drive coupling 41 and the driven coupling 42 are in contact with each other. 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 replaced with the second engaging portion. 42h. In the present embodiment, the position k at which the second engagement portion 42h and the contact surface 41c contact each other is the center k of rotation.

When the driven coupling 42 starts to rotate about the position k, the second engaging portion 42f approaches the contact surface 41c of the first engaging portion, and therefore the second engaging portion 42f and the contact surface 41c. 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 of the second engaging portion 42a in the intermediate transfer unit detaching direction (42g in FIG. 7). Hereinafter, the second engaging portion 42g) moves in the detaching 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 retreats 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, until the second engagement portion 42a and the first engagement portion 41b are disengaged, the rotational axis of the driven coupling 42 is relative to the rotational axis of the drive coupling 41. The distance to move in the unit detachment 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 is moved by the force acting in the detaching direction of the unit. A structure that can move in the unit separating direction with respect to the rotation shaft will be described. As can be seen from FIG. 5, the driven coupling 42 has a region having a sufficient width in which the driving coupling 41 is fitted. 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 rotating shaft of the driven coupling 42 can move in the unit detaching direction with respect to the rotating shaft 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 equal to or larger than β, when the driven coupling 42 rotates about the position k, the driven coupling 42f contacts the first engaging portion 41b before the second engaging portion 42f comes into contact with the driven coupling 42f. The evacuation of 42 in the M direction is completed.

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

Contrary to the above, when the intermediate transfer unit 12 is mounted on the main body of the image forming apparatus 100, the driven coupling 42 comes into contact with the guide member 46 of the main body 100 of the apparatus, and thus is retracted in the M direction in the figure. As a result, the driven coupling 42 can smoothly move to the position where it is meshed with the driving coupling 41. Then, in a state where the rotation axis of the driven coupling 42 and the rotation axis of the driving coupling 41 are substantially coincident with each other, as described above, when the rotation phases of the coupling match, the coupling meshes with each other, and the intermediate transfer unit 12 The mounting of the device on the apparatus main body 100 is completed.

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 engaging 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 rotation amount 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 the inclined surface 41e. Further, as shown in FIG. 11, the second engagement 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, 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 be more smoothly retracted in the M direction shown in the drawing, which is 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 moves 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 as the rotation center. , It is possible to retract 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 a drive coupling 51 and a driven coupling 52 mesh with each other at 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 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 coupling rig of the first embodiment.

As shown in FIGS. 14 to 15, similarly to the first embodiment, the rotation of the driven coupling 52 is stopped until the engagement of the second engaging portion 52a and the first engaging portion 51b is released. The distance that the shaft moves in the unit separation 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 rotation shaft of the driven coupling 52 can move in the unit detaching direction with respect to the rotation shaft of the drive coupling 51 is α. When α is equal to or larger than β, when the driven coupling 52 rotates about the position k, the driven coupling 52 is contacted 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 engagement 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 drawing, which is opposite to the urging direction B.

(Embodiment 3)
In the present embodiment, a drive transmission device in which a drive coupling 61 and a driven coupling 62 mesh with each other at a plurality of phases will be described. The configuration other than the drive transmission device is the same as that of 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.

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 coupling rig of the first embodiment.

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

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

Further, as shown in FIG. 22, the second engagement portion 62a of the driven coupling 62 may also have the 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 drawing, which is opposite to the urging direction B.

(Embodiment 4)
In the present embodiment, in the drive transmission device 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 against and contacts the drive coupling 41 will be described. 23. 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 drive coupling 41 by the biasing member 45, and the arcuate surface 42i comes into contact with the inclined surface 41e of the drive coupling 41, so that the driven coupling 42 has an axial direction. The position is determined.

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

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

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 part 16 Secondary transfer means 20 Paper discharge roller pair 22 Cleaning means 23 Separation means 24a-24d Developing roller 25a-25d Developer applying roller 30 Primary transfer spacing Means 31 Biasing member 32 Cam shaft 33 Sliding 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 device S Transfer material A, B, C, D, E, F, L, M direction G, H phase J, K position

The unit of the present invention for solving the above-mentioned problems is provided with a rotation axis of the first coupling with respect to an apparatus main body of an electrophotographic image forming apparatus having a first coupling including a first protrusion. A unit that can be removed along a substantially orthogonal detaching direction, and has a second coupling that rotates by engaging with the first coupling, and the second coupling engages with the first protrusion. The second main body, and 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. The second coupling is structured to be movable in the detaching direction with respect to the first coupling when the unit is pulled out in the detaching direction from the first coupling and the first coupling. In the process of moving the second coupling in the disengagement direction from the state in which the second coupling is engaged, at least one of the first coupling and the second coupling is provided. When the other comes into contact with the inclined surface, the second coupling starts withdrawal in a direction parallel to the rotation axis of the first coupling relative to the first coupling. And

Claims (4)

The device body,
A unit detachable from the main body of the apparatus,
A first coupling, which is provided in the main body of the apparatus and rotates by power from a drive source,
A second coupling that is provided in the unit and that rotates by meshing with the first coupling;
One of the first coupling and the second coupling has a concave shape, and the other coupling has a convex shape that enters the one coupling, and the convex cup has a concave shape. At least one of the outer peripheral portion of the ring and the inner peripheral portion of the concave coupling has an inclined surface,
At least one of the first coupling and the second coupling is retractable in a direction parallel to the rotation axis,
When the unit is pulled out from the device main body in a direction perpendicular to the rotation axis of the first coupling, the rotation axis of the second coupling causes the rotation axis of the second coupling to move by the force acting in the detaching direction of the unit. It is structured such that it can move in the unit detaching direction with respect to the rotation shaft of the first coupling, and at least one of the first coupling and the second coupling moves to the inclined surface by the movement of the rotation shaft. An image forming apparatus which is retracted along a direction parallel to the rotation axis. When the unit is pulled out from the apparatus main body in a direction perpendicular to the rotation axis of the first coupling, the second coupling causes the second coupling to move by the force acting in the detaching direction of the unit. With respect to the ring, rotation about a position different from the rotation axis of the first coupling and where the first coupling and the second coupling are in contact with each other is considered as the center of rotation. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Of the second coupling that rotates about a position that is different from the rotation axis of the first coupling and that is in contact with the first coupling and the second coupling. The rotation shaft has a maximum distance of the movable distance with respect to the rotation shaft of the first coupling in the disengagement direction as α, and at least one of the first coupling and the second coupling is By retracting along the inclined surface in the direction parallel to the rotating shaft, the convex coupling can be separated from the concave coupling, and the rotating shaft of the second coupling The image forming apparatus according to claim 2, wherein β is a distance moved in the disengagement direction with respect to the rotation axis of the first coupling, and α is larger than β. A first coupling that is rotated by power from a drive source;
A second coupling that is removable with respect to the first coupling and that rotates in mesh with the first coupling;
One of the first coupling and the second coupling has a concave shape, and the other coupling has a convex shape that fits into the one coupling. At least one of the outer peripheral portion of the ring and the inner peripheral portion of the concave coupling has an inclined surface,
At least one of the first coupling and the second coupling is retractable in a direction parallel to the rotation axis,
When pulling out the second coupling in a direction perpendicular to the rotation axis of the first coupling from a state where the first coupling and the second coupling are engaged with each other, the second cup The rotating shaft of the second coupling is structured to be movable in the unit separating direction more than the rotating shaft of the first coupling by the force acting in the separating direction of the ring. At least one of the first coupling and the second coupling is retracted in the direction parallel to the rotation axis along the inclined surface by the.

Images