JP6632408B2 - Drive transmission device and image forming apparatus - Google Patents

Description

  The present invention relates to a drive transmitting device for transmitting a driving force to a unit detachable from a main body of an image forming apparatus, and an image forming apparatus including the same.

  In recent years, operability has been desired to be improved in image forming apparatuses such as electrophotographic printers and copiers. From the viewpoint of improving the operability, a cartridge system in which a photosensitive member and process units such as a charging unit, a developing unit, and a cleaning unit that act on the photosensitive unit are integrally formed into a cartridge, and the cartridge is detachably mountable to an image forming apparatus main body. Has been adopted. The operability is further improved by this cartridge system, and the user can easily perform maintenance of the process means such as development.

  Similarly, the intermediate transfer member of the image forming apparatus main body also has a unit configuration, is detachable from the image forming apparatus main body, and improves operability and maintainability.

  Further, as a drive transmission device that stably and reliably transmits a driving force to these units that can be attached to and detached from the image forming apparatus main body, a coupling pair formed by a combination of a convex portion and a corresponding concave portion is used. Have been. In this case, when the unit is detached from the apparatus main body, it is necessary to move one of the coupling pairs to release the engagement. Conventionally, the coupling of the coupling pair is disconnected by moving the coupling on the apparatus main body side in the direction of the rotation axis so as to move away from the coupling on the unit side in conjunction with an operation of opening a cover that opens and closes the apparatus main body. Was commonly used.

  Patent Literature 1 discloses a configuration of a coupling mechanism that can be attached and detached without requiring an interlocking mechanism with the opening / closing cover as described above.

  On the other hand, regarding the driving mechanism of the image forming apparatus, a configuration in which the number of driving motors used is reduced as much as possible is often adopted from the viewpoint of miniaturization and cost reduction. Is branched using a gear train or the like to output a plurality of outputs. In the case where control for individually driving and stopping a part of the outputs of the developing unit and the transfer belt is performed on the plurality of outputs, the drive motor cannot be stopped. Therefore, a clutch mechanism may be provided to cut off the driving force.

  Patent Document 2 discloses an example of a specific configuration of a clutch mechanism. FIG. 14 shows the configuration of a conventional clutch mechanism. 101 is a drive input gear, 103 is an input side engaging member slidable in the axial direction, and 102 is a spring for applying an urging force to the input side engaging member. The input side engaging member 103 has an area that can slide in the axial direction. The input side engaging member 103 has a projection 103a that meshes with a groove provided inside the drive input gear 101, and rotates integrally with the drive input gear 101 when the two engage. 104 is an output shaft, 105 is an output side engaging member that rotates integrally with the output shaft 104, and 106 is a parallel pin for fixing the output side engaging member 105 to the output shaft 104. 109 is a bearing. Reference numerals 107 and 108 denote engagement control members for controlling the engagement state and the disengagement state by moving the input side engagement member 103, and both have a cylindrical cam 107a and a cylindrical cam 108a.

  In the case of the above-mentioned engagement state, as shown in FIG. 15, the engagement control member 108 is rotated by a lever or the like (not shown) so as to be in a position where the cylindrical cam does not act. Then, the input side engaging member 103 is moved by the elastic force of the spring 102 and is pressed against the output side engaging member 105 to be engaged.

  On the other hand, in the case of the above-mentioned disengagement state, as shown in FIG. 16, the engagement control member 108 is rotated by a lever or the like (not shown), and the engagement control member 107 is controlled by the action of the cylindrical cam. The member is moved away from the member 108. Then, the engagement control member 107 pushes the input side engagement member 103 against the spring 102 to release the engagement with the output side engagement member 105.

Japanese Patent No. 5559379 Japanese Patent No. 3885960

  However, since the clutch mechanism disclosed in Patent Document 2 cannot move the output shaft in the axial direction, the movable coupling mechanism disclosed in Patent Document 1 is disposed on the output shaft. I couldn't do that.

  That is, the coupling mechanism disclosed in Patent Document 1 has a configuration in which one of the coupling pairs moves in the axial direction with the attachment / detachment operation of the attachment / detachment unit. On the other hand, in the clutch mechanism disclosed in Patent Document 2, when the output shaft 104 is urged toward the frame 110, the urging force is transmitted in the order of the drive input gear 101, the output side engagement member 105, and the bearing 109, and Is regulated by the frame 110. Therefore, in the clutch mechanism disclosed in Patent Document 2, the output shaft 104 cannot move in the axial direction in any of the engaged state shown in FIG. 15 and the disengaged state shown in FIG.

  Therefore, as described above, the coupling mechanism cannot be disposed on the shaft of the conventional clutch mechanism.

  An object of the present invention is to make it possible to move the coupling member in the axial direction by the attachment / detachment operation of the unit in either the state where the driving force is released or the state where the driving force is transmitted.

  In order to achieve the above object, the present invention is a drive transmission device that engages with a detachable unit with respect to an image forming apparatus main body and transmits or disconnects a driving force to or from the unit. A drive output member that engages with the unit and transmits a driving force; a drive input member; and a drive output member that is provided to be movable in the axial direction of the drive output member with respect to the drive output member. An input side engaging member that rotates integrally with the drive input member, and an output side that is engageable with the input side engaging member, rotates integrally with the drive output member, and moves integrally with the axial direction. An engagement member, an elastic member provided between the drive input member and the input side engagement member, for urging the input side engagement member toward the output side engagement member, and the output side engagement The insertion position is in an engagement position where the member can be engaged. A disengagement position in which the input side engagement member is disengaged from the output side engagement member by moving the side engagement member in the axial direction against the urging force of the elastic member. And a disengagement member that disconnects the transmission of the driving force to the unit, wherein the input side engagement member is in the engagement position and in the disengagement position. In each case, a space is formed that allows the output side engaging member to move in the axial direction when the drive output member is pressed in the axial direction.

  According to the present invention, in either the state in which the driving force is released or the state in which the driving force is transmitted, the movement of the drive output member in the axial direction is permitted. Can be moved.

1 is a cross-sectional view illustrating a configuration example of an image forming apparatus according to a first embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating attachment and detachment of the process cartridge according to the first embodiment of the present invention. FIG. 4 is a perspective view illustrating a coupling member according to the first and second embodiments of the present invention. The figure explaining operation | movement of the coupling member which concerns on Example 1, 2 of this invention. The figure explaining operation | movement of the coupling member which concerns on Example 1, 2 of this invention. FIG. 2 is a perspective view illustrating a configuration of a clutch mechanism according to the first and second embodiments of the present invention. FIG. 4 is a cross-sectional view illustrating an engaged state of the clutch mechanisms according to the first and second embodiments of the present invention. Sectional drawing explaining movement of the output shaft in the engaged state of the clutch mechanism according to the first and second embodiments of the present invention. Sectional drawing explaining the disengagement state of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing explaining movement of the output shaft in the disengaged state of the clutch mechanism according to the first and second embodiments of the present invention. FIG. 4 is a cross-sectional view illustrating a configuration example of an image forming apparatus according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating attachment and detachment of an intermediate transfer unit according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a separation mechanism of a primary transfer roller according to a second embodiment of the present invention. A perspective view for explaining the configuration of a conventional clutch mechanism. Sectional drawing explaining the engagement state of the conventional clutch mechanism. Sectional drawing explaining the disengaged state of the conventional clutch mechanism.

  Hereinafter, preferred embodiments of the present invention will be illustratively described in detail. However, the dimensions, materials, shapes, relative positions, and the like of the components described in this embodiment are appropriately changed depending on the configuration of the mechanism to which the present invention is applied and various conditions. Unless otherwise, the scope of the present invention is not intended to be limited thereto.

[Example 1]
FIG. 1 is a cross-sectional view illustrating a configuration example of a drive transmission device having a clutch mechanism according to a first embodiment of the present invention and an image forming apparatus including the same. The clutch mechanism in the drive transmission device will be described in detail with reference to FIG. The image forming apparatus 1 is a monochrome image forming apparatus using an electrophotographic image forming process.

  As shown in FIG. 1, an image forming unit that forms an image on a sheet is provided inside the image forming apparatus 1. The image forming section includes the photosensitive drum 2 as an “image carrier”, a developing roller 19 as a “developing device”, a transfer roller 3 as a “transfer device”, and the like. In this example, the photosensitive drum 2 is included in the process cartridge 4, and has a configuration in which the user can replace (removably attach) the process cartridge 4 to the image forming apparatus 1. The process cartridge includes, as process means acting on the photosensitive drum 2, a charging roller (charging means), a cleaning device (cleaning means), and the like (not shown) in addition to the developing device (developing means) described above. In.

  In the image forming apparatus 1, a feed cassette 5 on which sheets S for forming an image are stacked is arranged. The controller (control unit) 6 controls the rotation of a drive motor (drive source) (not shown), and the feed roller 7 rotates to separate and feed one sheet. It is conveyed in the order of the drum 2 and the transfer roller 3. The image writing laser scanner 9 emits a laser beam L, draws an electrostatic latent image on the surface of the photosensitive drum 2 charged by the charging roller, and places the electrostatic latent image on the photosensitive drum 2 by a developing device including the developing roller 19. The toner image is developed. This toner image is transferred between the photosensitive drum 2 and the transfer roller 3 onto the first surface of the sheet. Thereafter, the sheet is heated and fixed by the fixing device 10, and is conveyed in the order of the discharge roller pair 11 and the discharge tray 12.

  Further, the image forming apparatus 1 is provided with a double-sided unit including a reversing conveyance path 13 and a double-sided conveyance path 14. Downstream of the fixing device 10, there is provided a reverse conveyance path 13 branched to another route up to the discharge roller pair 11. The branching unit has a path switching unit 15 and is driven by a driving source (not shown). In the reversing conveyance path 13, a pair of reversing conveyance rollers 16 capable of normal rotation and reverse rotation for reversing conveyance of the sheet is provided, and when image formation is performed on both sides of the sheet, image formation on the first side is performed. The sheet on which the printing has been completed is reversed and conveyed to the double-sided conveying path 14. Thereafter, the sheet is again fed into the image forming unit by the plurality of transport roller pairs 17 in a state where the first surface and the second surface of the sheet are reversed. The subsequent operation is the same as that of the first surface.

  When the user replaces the process cartridge 4, the user opens the open / close cover 18 of the image forming apparatus 1 as shown in FIG. The direction in which the process cartridge 4 is pulled out and the direction in which the process cartridge 4 is mounted are, as indicated by arrows in FIG.

  A drive transmission unit from the image forming apparatus 1 to the process cartridge 4 includes a coupling constituting a drive transmission device. In the present embodiment, two sets of couplings, ie, a drive input to the photosensitive drum 2 and a drive input to the developing roller 19, are provided. However, the two sets need not necessarily have a single coupling configuration. The set only needs to have the configuration shown in this embodiment.

  The coupling configuration in the present embodiment will be described with reference to FIG. FIG. 3 shows an example of a coupling shape in the present embodiment. The shape shown in FIG. 3 is a known technology disclosed in Patent Literature 1, and is not limited to this shape, and may be any shape having the same effect and operation.

  A set of couplings shown in FIG. 3 includes a drive coupling 20 on the apparatus main body side and a driven coupling 21 on the process cartridge side. The drive coupling 20 is provided in the apparatus main body of the image forming apparatus 1 and is a coupling that is rotated by power from a drive source. The drive coupling 20 has a clutch member described later coaxially. The driven coupling 21 is provided in the process cartridge 4, which is a unit detachable from the apparatus main body, and is a coupling that rotates while meshing with the driving coupling 20. The image forming apparatus according to the present embodiment has a configuration in which a single motor (drive source) drives not only the process cartridge but also a feeding mechanism and each transport roller.

  The coupling operation when the process cartridge is mounted will be described with reference to FIG. FIG. 4 is a diagram showing a state immediately before the couplings 20 and 21 are engaged with the process cartridge 4 inserted into the apparatus main body, as viewed from a direction perpendicular to the axis of the coupling. FIG. 4 illustrates a set of couplings for simplicity for illustration. In this embodiment, the process cartridge 4 is inserted in the direction of arrow 25. Then, when the couplings are engaged with each other, the tapered surface 22 of the outer periphery of the driving coupling 20 comes into contact with the tapered surface 23 of the driven coupling 21, and the driving coupling 20 receives a force and receives an arrow 24 substantially perpendicular to the direction of the arrow 25. (Axial direction). Therefore, the couplings 20 and 21 can be engaged. At least one of the tapered surfaces 22 and 23 at the distal end (outer periphery) of each coupling is not limited to the inclined surface, but may be a curved surface such as a part of a spherical surface.

  FIG. 5 illustrates a coupling operation when the process cartridge is detached. FIG. 5 is a view of a cross section in a state where the coupling is engaged, viewed from a direction perpendicular to the axis of the coupling. Note that FIG. 5 also shows a set of couplings for simplicity for description, similarly to FIG. In this embodiment, the process cartridge 4 is detached in the direction of arrow 26. Then, the tapered surface 28 of the inner periphery of the driving coupling 20 and the tapered surface 22 of the driven coupling 21 come into contact with each other, and the driving coupling 20 receives a force and receives a force in the direction of the arrow 27 (axial direction) substantially orthogonal to the direction of the arrow 26. Go to). Therefore, the couplings 20 and 21 are disengaged and can be separated. The tapered surface 28 at the tip (inner circumference) of the coupling is not limited to an inclined surface, but may be a curved surface such as a part of a spherical surface.

  Also, here, the tip of the driven coupling 21 on the process cartridge side has a convex shape, and the tip of the drive coupling 20 on the apparatus main body side has a concave shape engaging with the convex shape. It is not something to be done. In order to achieve the above operation, the shapes of the drive coupling 20 and the driven coupling 21 may be exchanged, and the concavo-convex shape may be reversed. That is, the distal end of the drive coupling on the apparatus main body side may have a convex shape, and the distal end of the driven coupling on the process cartridge side may have a concave shape engaging with the convex shape.

  Next, the clutch mechanism in the drive transmission device, which is a characteristic configuration of the present invention, will be described in detail.

  In this embodiment, a clutch mechanism is provided inside the image forming apparatus 1 coaxially with the coupling 20 for transmitting the drive to the developing roller 19. By providing the clutch mechanism, the driving force can be cut off when rotation is unnecessary. Accordingly, various developing devices including the toner as the developer and the developing roller included in the process cartridge can be protected from deterioration due to the image forming process. A similar clutch mechanism may be provided on the coupling shaft of the photosensitive drum, or may be provided on the process cartridge.

  FIG. 6 shows a clutch mechanism in this embodiment. The clutch mechanism includes a drive input gear 31, a spring 32, an input side engagement member 33, an output shaft 34, a drive output side engagement member 35, a parallel pin 36, engagement control members 37 and 38, and a bearing 39. The drive input gear 31 is a drive input member. The input side engaging member 33 is movable in the axial direction. The spring 32 is a compression spring as an elastic member that applies an urging force to the input side engaging member 33. The input side engaging member 33 has a projection 33a that meshes with a groove provided inside the drive input gear 31. The input side engaging member 33 rotates integrally with the drive input gear 31 when the protrusion 33a meshes with the groove of the drive input gear 31. Further, the input side engaging member 33 has a region that can move in the axial direction. Since the spring 32 also rotates integrally with the drive input gear 31, the spring end does not slide and slide. The output shaft 34 is a drive output member, and has at one end a drive coupling 20 that engages with the driven coupling 21 (see FIG. 3) on the process cartridge side. An e-ring 34a as a retaining member is attached to the other end of the output shaft 34, and the output shaft 34 and the e-ring 34a are integrated in the axial direction. The drive output side engagement member 35 rotates integrally with the output shaft 34. The parallel pin 36 fixes the drive output side engagement member 35 to the output shaft 34. Thus, the output shaft 34 and the drive output side engagement member 35 are integrally formed in the axial direction, and are integrally rotated around the output shaft 34. The bearing 39 is a bearing member that supports the engagement control member 37 so as to be movable in the axial direction and restricts rotation, supports the engagement control member 38 rotatably, and supports the engagement control member 37 on the frame member 40 of the image forming apparatus main body. On the other hand, the output shaft 34 is supported so as to be rotatable and movable in the axial direction. The engagement control member 37 and the engagement control member 38 move the input side engagement member 33 in the axial direction to engage with the output side engagement member 35 or an engagement release state for releasing the engagement. , And has a cylindrical cam 37a and a cylindrical cam 38a, respectively.

  Here, the engagement state and the disengagement state of the input side engagement member 33 and the output side engagement member 35 with the engagement control members 37 and 38 will be described.

  First, the engaged state will be described with reference to FIG. FIG. 7 is a sectional view of the engaged state. The frame member 40 is a member that holds the clutch mechanism. At the time of engagement, the engagement control member 38 is rotated by a lever or the like (not shown) to a position where the cylindrical cams 37a and 38a do not act. Then, the input side engaging member 33 urged toward one side in the axial direction by the elastic force of the spring 32 is moved to one side in the axial direction, and is pressed against and engaged with the output side engaging member 35. You. At this time, the drive input gear 31 is urged toward the other side in the axial direction by the elastic force of the spring 32, and abuts against the contact surface 34b of the output shaft 34. At this time, it can be said that the input side engagement member 33 is at an engagement position where it can be engaged with the drive output side engagement member 35.

  In this engaged state, as shown in FIG. 7, the engagement control member 37 comes into contact with the input side engagement member 33 and the shaft of the output shaft 34 is located between the output side engagement member 35 and the bearing 39. A space A that allows movement in the direction is provided. That is, when the engagement control member 37 contacts the input side engagement member 33, the drive input gear 31 presses the contact surface 34 b by the urging force of the spring 32 and presses the output shaft 34 in the direction of the arrow 43. . Then, the e-ring 34a abuts the bearing 39 in the axial direction. Accordingly, the position of the output shaft 34 in the axial direction is determined in a state where the space A that allows the output shaft 34 to move in the axial direction is provided between the output side engaging member 35 and the bearing 39. The output shaft 34 may not necessarily be configured to be pressed in the direction of the arrow 43 by the urging force of the spring 32. That is, when the input side engagement member 33 and the drive output side engagement member 35 are engaged, the engagement control member 37 does not come into contact with the input side engagement member 33, and is caused by an urging member different from the spring 32. The output shaft 34 may be pressed in the direction of arrow 43.

  The space A allows the drive output side engagement member 35 to move in the axial direction and away from the input side engagement member 33, and allows the drive output side engagement member 35 to move in the axial direction. As a result, the movement of the output shaft 34 in the axial direction is permitted. A space B different from the space A that allows the output shaft 34 to move in the axial direction is provided between the input side engagement member 33 and the drive input gear 31. The space B allows the drive input gear 31 to move in the axial direction and in a direction approaching the input side engaging member 33, and by allowing the drive input gear 31 to move in the axial direction, results in an output shaft. 34 is allowed to move in the axial direction.

  FIG. 8 shows an operation in the case where the mounting / dismounting operation of the process cartridge is performed in a direction substantially perpendicular to the drive shaft (the direction of the arrow 25 in FIG. 4) in the engaged state. As described above, the coupling 20 on the apparatus main body side is pushed toward the frame member 40 (in the direction of arrow 41) by a predetermined amount by the coupling on the process cartridge side by the mounting / removing operation of the process cartridge. As a result, the output shaft 34 is pressed to one side (the direction of arrow 41) in the axial direction, and the drive input gear 31 pressed by the contact surface 34b and the output side fixed to the output shaft 34 by the parallel pin 36. Both the engaging member 35 and the engaging member 35 move in the arrow 41 direction. The drive input gear 31 moves in the direction of the arrow 41 against the urging force of the spring 32. On the other hand, the input side engaging member 33 in contact with the engagement control member 37 does not move, and the spring 32 interposed between the drive input gear 31 and the input side engaging member 33 is compressed. Here, as shown in FIG. 7, in the present configuration, there is a space A between the output side engaging member 35 and the bearing 39 that allows the output shaft 34 to move in the axial direction. Can be moved in the axial direction of the output shaft 34 within the range of.

  When the pressing of the coupling 20 on the apparatus main body side in the direction of the arrow 41 by the coupling on the process cartridge side is released, the drive input gear 31 presses the contact surface 34 b by the urging force of the spring 32 to move the output shaft 34. Press in the direction of arrow 43 (FIG. 7). Then, the e-ring 34a hits the bearing 39 in the axial direction, and returns to the original state.

  In addition, by adopting the above configuration, the spring 32 that urges the input side engagement member 33 can be used as an urging force for returning to the original state against the movement of the output shaft 34, and newly added. The above operation can be realized without adding an urging member. The output shaft 34 may be pressed in the direction of arrow 43 (FIG. 7) by a new urging member. Even in such a configuration, the urging force of the spring 32 can be used as the urging force for returning to the original state, so that the urging force of the new urging member can be compared with the case where the urging force of the spring 32 is not used at all. Can be reduced accordingly. Furthermore, since it is built into the clutch mechanism, there is no rotational sliding portion with other members, which is also advantageous in terms of noise and wear. After the mounting / removal operation of the process cartridge is performed, the output shaft 34 is urged by the urging force of the spring 32 so as to have a positional relationship shown in FIG.

  Next, the disengaged state will be described with reference to FIG. FIG. 9 is a sectional view of the disengaged state. To release the engagement, the engagement control member 38 is rotated by a lever or the like (not shown), and the engagement control member 37 is acted on the cylindrical cam 37a by the cylindrical cam 38a of the engagement control member 38 to drive the engagement control member 37 to the drive input gear. Move to the 31 side. Then, the engagement control member 37 moves the input side engagement member 33 to the other side in the axial direction. As a result, the input side engagement member 33 is separated from the output side engagement member 35 and the engagement is released. . At this time, it can be said that the input side engaging member 33 is at the disengaged position. At this time, the spring 32 is compressed between the input side engaging member 33 and the drive input gear 31 by an amount corresponding to the movement of the input side engaging member 33. That is, the engagement control member 37 has moved the input side engagement member 33 from the engaged position to the disengaged position against the urging force of the spring 32 (compressing the spring 32).

  In this disengaged state, as shown in FIG. 9, the engagement control member 37 comes into contact with the input side engagement member 33, and the output shaft 34 is disposed between the output side engagement member 35 and the bearing 39. A space A that allows movement in the axial direction is provided. That is, when the engagement control member 37 contacts the input side engagement member 33, the drive input gear 31 presses the contact surface 34 b by the urging force of the spring 32 and presses the output shaft 34 in the direction of the arrow 44. . Then, the e-ring 34a abuts the bearing 39 in the axial direction. Accordingly, the position of the output shaft 34 in the axial direction is determined in a state where the space A that allows the output shaft 34 to move in the axial direction is provided between the output side engaging member 35 and the bearing 39.

  Further, a space B different from the space A that allows the output shaft 34 to move in the axial direction is provided between the input side engagement member 33 and the drive input gear 31. The space B allows the drive input gear 31 to move in the axial direction and in a direction approaching the input side engaging member 33, and by allowing the drive input gear 31 to move in the axial direction, results in an output shaft. 34 is allowed to move in the axial direction.

  FIG. 10 shows an operation when the process cartridge is detached in the direction substantially perpendicular to the drive shaft (the direction of arrow 25 in FIG. 4) in the disengaged state. As described above, the coupling 20 on the apparatus main body side is pushed by the predetermined amount toward the frame member 40 (the direction of the arrow 42) by the coupling on the process cartridge side by the mounting / removing operation of the process cartridge. As a result, the output shaft 34 is pressed to one side (the direction of the arrow 42) in the axial direction, and the drive input gear 31 pressed by the contact surface 34b and the output side fixed to the output shaft 34 by the parallel pin 36. Both the engaging member 35 moves in the direction of the arrow 42. The drive input gear 31 moves in the direction of the arrow 42 against the urging force of the spring 32. On the other hand, the input side engaging member 33 in contact with the engagement control member 37 does not move, and the spring 32 interposed between the drive input gear 31 and the input side engaging member 33 is further compressed. Here, as shown in FIG. 9, in the present configuration, between the output-side engaging member 35 and the bearing 39 and between the drive input gear 31 and the input-side engaging member 33, in the axial direction of the output shaft 34, respectively. Spaces A and B are provided to allow the movement of. Therefore, it is possible to move in the axial direction of the output shaft 34 in the range of the space A and the space B.

  When the pressing of the coupling 20 on the apparatus main body side in the direction of the arrow 42 by the coupling on the process cartridge side is released, the drive input gear 31 presses the contact surface 34 b by the urging force of the spring 32 to move the output shaft 34. Press in the direction of arrow 44 (FIG. 9). Then, the e-ring 34a hits the bearing 39 in the axial direction, and returns to the original state.

  In addition, by adopting the above configuration, the spring 32 that urges the input side engagement member 33 can be used as an urging force for returning to the original state against the movement of the output shaft 34, and newly added. The above operation can be realized without adding an urging member. Note that the output shaft 34 may be pressed in the direction of the arrow 44 (FIG. 9) by a new urging member. Even in such a configuration, the urging force of the spring 32 can be used as the urging force for returning to the original state, so that the urging force of the new urging member can be compared with the case where the urging force of the spring 32 is not used at all. Can be reduced accordingly. Furthermore, since it is built into the clutch mechanism, there is no rotational sliding portion with other members, which is also advantageous in terms of noise and wear. After the mounting / removal operation of the process cartridge is performed, the output shaft 34 is urged by the urging force of the spring 32 so as to have the positional relationship shown in FIG.

  The replacement of the process cartridge is performed at a timing when the image forming operation is not performed. In this example, control is performed to release the drive to the developing unit by releasing the engagement of the clutches (engagement members 33 and 35) at the end timing of the image forming operation. Therefore, the process cartridge is usually replaced in a state where the engagement of the clutches (engagement members 33 and 35) is released.

  However, there is a possibility that the image forming apparatus is stopped in a state where the clutch (engagement members 33 and 35) is engaged and the process cartridge is attached / detached for some reason such as power-off. In the present embodiment, the above configuration allows the output shaft 34 to move in the axial direction even when the clutch (engagement members 33, 35) is engaged, so that the process cartridge is removable.

  As described above, according to the present embodiment, in either the state where the driving force is released or the state where the driving force is transmitted, the axial movement of the output shaft 34 is allowed. With this, the coupling can be moved in the axial direction.

[Example 2]
FIG. 11 is a cross-sectional view illustrating a configuration example of a drive transmission device having a clutch mechanism according to the second embodiment of the present invention and an image forming apparatus including the same. The clutch mechanism in the drive transmission device is the same as that described in the first embodiment. About the same structure and effect as Example 1, the same code | symbol is used and it abbreviate | omits suitably.

  The image forming apparatus 50 according to the present embodiment is an inline color image forming apparatus using an electrophotographic image forming process. As shown in FIG. 11, inside the image forming apparatus 50, four process cartridges for forming an image are provided. Each process cartridge includes a photosensitive drum 2a, 2b, 2c, 2d as an "image carrier", a developing roller (not shown), a charging roller (not shown), a cleaning device (not shown), and the like. Each process cartridge is configured to be exchangeable (removable) by the user with respect to the apparatus main body of the image forming apparatus 50. These four process cartridges 51a, 51b, 51c, 51d have the same structure, but form images of different colors using yellow (Y), magenta (M), cyan (C), and black (Bk) toners. Is different.

  The image writing laser scanner 52 emits four laser beams L and draws an electrostatic latent image on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d charged by a charging roller (not shown). Toner is supplied to the electrostatic latent image, and Y, M, C, and Bk toner images are formed on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. The toner images formed on the surfaces of the photoreceptor drums 2a, 2b, 2c, and 2d are primarily transferred to the surface of the intermediate transfer belt 53 in order. The intermediate transfer unit 56 mainly includes an intermediate transfer belt 53 as an intermediate transfer body, a driving roller 57, a driven roller 58, four primary transfer rollers 59a, 59b, 59c, 59d as primary transfer units, a cleaning unit 60, It is composed of primary transfer separation means shown in FIG. The intermediate transfer belt 53 is stretched around a driving roller 57 and a driven roller 58. The driven roller 58 is urged by urging means (not shown), and applies a predetermined tension to the intermediate transfer belt 53. Each of the primary transfer rollers 59a, 59b, 59c, 59d is disposed inside the intermediate transfer belt 53 so as to face each of the photosensitive drums 2a, 2b, 2c, 2d. It is biased toward the photosensitive drum.

  The transfer of the toner image onto the sheet S is performed by the secondary transfer unit 54 while the sheet is conveyed by the feeding roller 7. The intermediate transfer belt 53 included in the intermediate transfer unit 56 carries the toner image formed by the primary transfer process and transports the toner image to the secondary transfer unit 54. In the secondary transfer unit 54, a bias is applied to the secondary transfer unit 55, and the toner image on the intermediate transfer belt 53 is transferred onto the conveyed sheet S. The fixing device 10 is located on the downstream side of the secondary transfer unit 54, and fixes the toner image transferred on the sheet onto the sheet S. The sheet on which the image is fixed is conveyed in the order of the discharge roller pair 11 and the discharge tray 12.

  In the present embodiment, the intermediate transfer unit 56 is a unit that can be attached to and detached from the apparatus main body of the image forming apparatus 50. As shown in FIG. 12, the opening / closing member 61 of the apparatus main body is opened, and the intermediate transfer unit 56 is configured to be detachable from the apparatus main body in a direction indicated by an arrow. The direction in which the intermediate transfer unit 56 is pulled out and the direction in which the intermediate transfer unit 56 is attached are directions substantially orthogonal to the axial direction of the photosensitive drum 2 and a drive input shaft for inputting drive to the intermediate transfer unit 56.

  The intermediate transfer unit 56 has separation means for primary transfer rollers corresponding to Y, M, and C that are in contact with the respective photosensitive drums via the intermediate transfer belt 53 during color image formation. This is to prevent the rubbing of the photosensitive drum that is not used at the time of forming a monochrome image and to extend the life of the photosensitive drum.

  FIG. 13 shows an example of the primary transfer separating means in the present embodiment, and is a diagram showing a cross section of the photosensitive drum in the axial direction. The primary transfer separation means is mainly composed of a cam 63 and a slide member 62, and is provided in a pair at both ends in the axial direction of the transfer roller. By rotating the cam 63 and moving the slide member 62 left and right (in the direction of the arrow), it is possible to control the contact / separation positions of the primary transfer rollers 59a, 59b, 59c with respect to the respective photosensitive drums. The driving force of the cam 63 is transmitted from the apparatus main body of the image forming apparatus. As described above, since the intermediate transfer unit 56 is detachable, the coupling shown in FIG. 3 is used for the drive connecting portion. The drive coupling 20 is provided on the apparatus main body side, and the driven coupling 21 is provided on the intermediate transfer unit 56 side. Further, in order to perform control for rotating and stopping the cam 63, a clutch mechanism shown in FIGS. 6, 7, 8, 9, and 10 is provided in the apparatus main body on the drive shaft of the cam 63. The operations of the coupling and the clutch mechanism when attaching and detaching the intermediate transfer unit are the same as the operations described in the first embodiment. The configurations of the coupling and the clutch mechanism are the same as those described in the first embodiment. Therefore, detailed description is omitted here.

  As described above, also in this embodiment, in either the state in which the driving force is released or the state in which the driving force is transmitted, the movement of the output shaft in the axial direction is permitted. The coupling can be moved axially. Thus, the intermediate transfer unit can be detached from the apparatus main body regardless of the engagement / disengagement state of the clutch mechanism.

[Other embodiments]
In the above-described embodiment, the process cartridge and the intermediate transfer unit are illustrated as units detachable from the image forming apparatus main body. However, the units are not limited thereto. It is a unit that can be attached to and detached from the apparatus main body, and may be a unit that operates by receiving a driving force transmitted from the apparatus main body side. The effect can be expected. Also, as the process cartridge as the detachable unit, a process cartridge having a photosensitive drum and a charging unit, a developing unit, and a cleaning unit as process units acting on the photosensitive drum is exemplified, but is not limited thereto. is not. In addition to the photoreceptor drum, a process cartridge having any one of a charging unit, a developing unit, and a cleaning unit may be used.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, another image forming apparatus such as a copying machine or a facsimile apparatus, or another image forming apparatus such as a multifunction machine combining these functions may be used. In these image forming apparatuses in which the unit is detachable, the same effect can be obtained by applying the present invention to a drive transmission device that transmits a driving force to the unit. Further, in the above-described embodiment, the image forming apparatus in which the unit having the belt (intermediate transfer member) for carrying the image to be transferred to the sheet is detachable is exemplified, but the present invention is not limited to this. An image forming apparatus in which a unit having a transport belt for carrying and transporting a sheet may be detachable. In this image forming apparatus, a similar effect can be obtained by applying the present invention to a drive transmission device that transmits a driving force to the unit.

1, 50 ... image forming apparatus 2 ... photosensitive drum 4 ... process cartridge 19 ... developing rollers 20, 21 ... driven couplings 22, 23, 28 ... tapered surface 31 ... drive input gear 32 ... spring 33 ... input side engagement Member 33a Projecting portion 34 Output shaft 35 Drive output side engaging member 36 Parallel pin 37 Engagement control members 37a, 38a Cylindrical cam 38 Engagement control member 39 Bearing 40 Frame member 50 Image formation apparatus

Claims (13)

A drive transmission device that engages with a detachable unit with respect to the image forming apparatus main body and transmits or disconnects a driving force to the unit,
A drive output member that includes a coupling engageable with the unit and that transmits a driving force by engaging with the unit;
A drive input member,
An input-side engaging member that is provided movably in the axial direction of the drive output member with respect to the drive output member, and that rotates integrally with the drive input member;
An output-side engaging member that is engageable with the input-side engaging member, rotates integrally with the drive output member, and moves integrally in the axial direction;
An elastic member provided between the drive input member and the input side engaging member, for urging the input side engaging member toward the output side engaging member;
The input side engaging member is moved in the axial direction against the urging force of the elastic member, thereby moving the input side engaging member at the engagement position where the input side engaging member can be engaged with the output side engaging member. An engagement release member that moves to an engagement release position where the engagement with the output side engagement member is released, and cuts off transmission of driving force to the unit.
Has,
When the drive output member is pressed in the axial direction in each of the state where the input side engagement member is in the engagement position and the state where the input side engagement member is in the disengagement position, the output side engagement member is moved to the shaft. A drive transmission device, wherein a space allowing movement in a direction is formed.   When the drive output member is pressed in the axial direction in each of the state where the input side engagement member is at the engagement position and the state where the input side engagement member is at the disengagement position, the drive input member moves in the axial direction. The drive transmission device according to claim 1, wherein a space that allows the movement of the drive transmission is formed.   When the drive output member is pressed in the axial direction in each of the state where the input side engagement member is at the engagement position and the state where the input side engagement member is at the disengagement position, the drive input member is connected to the drive output member. 3. The drive transmission device according to claim 1, wherein the drive transmission device is pressed in the axial direction and moves in the axial direction against the urging force of the elastic member. 4.   In each of the state where the input side engagement member is at the engagement position and the state at the engagement release position, when the drive output member is pressed in the axial direction, the output side engagement member is The drive transmission device according to any one of claims 1 to 3, wherein the drive transmission device moves in an axial direction and in a direction away from the input side engagement member.   A bearing member for supporting the drive output member rotatably and axially movably with respect to a frame member of the image forming apparatus main body, wherein the space is provided between the output side engagement member and the bearing member. The drive transmission device according to claim 1, wherein the drive transmission device is provided.   The drive transmission device according to claim 1, wherein the elastic member rotates integrally with the drive input member.   The drive transmission device according to any one of claims 1 to 6, wherein the elastic member is a compression spring.   The drive transmission device according to any one of claims 1 to 7, wherein the coupling included in the drive output member has an inclined surface or a curved surface at a tip portion that engages with the unit.   The drive transmission device according to claim 8, wherein the coupling included in the drive output member has a convex shape at a distal end portion that engages with the unit.   The drive transmission device according to claim 8, wherein the coupling included in the drive output member has a concave shape at a distal end portion that engages with the unit. An image forming apparatus that has a drive transmission device that engages with a detachable unit with respect to the image forming apparatus main body and transmits or cuts a driving force to the unit and forms an image on a sheet,
An image forming apparatus comprising: the drive transmission device according to claim 1 as the drive transmission device.   The image forming apparatus according to claim 11, wherein the unit is a process cartridge having an image carrier and a process unit acting on the image carrier.   The image forming apparatus according to claim 11, wherein the unit is a unit having a sheet or a belt that carries an image to be transferred to the sheet.

Images