JP2016177269A - Drive transmission device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a coupling member in the shaft direction by a detachable operation of a unit in any of a state releasing a driving force or the state transmitting the driving force.SOLUTION: A drive transmission device includes: a drive output member having a coupling engageable with a unit; a drive input member; an input side engagement member; an output side engagement member engageable with the input side engagement member; an elastic member for energizing the input side engagement member toward the output side engagement member; and an engagement releasing member for moving the input side engagement member being at the engagement position of being engageable with the output side engagement member toward an engagement release position released from the engagement with the output side engagement member. In any of state in which the input side engagement member is located at the engagement position and the state in which the input side engagement member is located at the engagement release position, a space is formed in which the output side engagement member is allowed to move to a shaft direction when the drive output member is pushed toward the shaft direction.SELECTED DRAWING: Figure 9

Description

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

  In recent years, improvement in operability is desired in image forming apparatuses such as electrophotographic printers and copiers. From the viewpoint of improving operability, there is a cartridge system in which the photosensitive member and the process means such as a charging means, a developing means, and a cleaning means that act on the photosensitive member are integrated into a cartridge and can be attached to and detached from the image forming apparatus main body. It 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 has a unit configuration and is detachable from the image forming apparatus main body, thereby improving operability and maintenance.

  In addition, as a drive transmission device that stably and reliably transmits driving force to these units that can be attached to and detached from the image forming apparatus main body, a coupling pair that is formed by a combination of a convex portion and a corresponding concave portion is used. It has 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 pair is uncoupled by moving in the direction of the rotation axis so that the coupling on the apparatus body side is separated from the coupling on the unit side in conjunction with the operation of opening the cover that opens and closes to the apparatus body. Was often used.

  Patent Document 1 discloses a configuration of a detachable coupling mechanism that eliminates the need for an interlocking mechanism with the opening / closing cover as described above.

  On the other hand, with respect to the drive mechanism of the image forming apparatus, a configuration in which the number of drive motors used is reduced as much as possible from the viewpoint of miniaturization and cost reduction is often adopted. The output is branched using a gear train or the like to output a plurality of outputs. For the plurality of outputs, for example, when the control for individually driving / stopping some outputs of the developing unit and the transfer belt is performed, the drive motor cannot be stopped. For this reason, there is a case where the driving force is cut by providing a clutch mechanism.

  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 that is slidable in the axial direction, and 102 is a spring that applies a biasing force to the input side engaging member. The input side engaging member 103 has a region that can slide in the axial direction. Further, the input side engaging member 103 has a protrusion 103 a that meshes with a groove provided inside the drive input gear 101, and rotates together with the drive input gear 101 by engaging both. Reference numeral 104 denotes an output shaft, 105 denotes an output side engaging member that rotates integrally with the output shaft 104, and 106 denotes a parallel pin for fixing the output side engaging member 105 to the output shaft 104. Reference numeral 109 denotes a bearing. Reference numerals 107 and 108 denote engagement control members that move the input side engagement member 103 to control the engagement state and the engagement release state, and both have a cylindrical cam 107a and a cylindrical cam 108a.

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

  On the other hand, when the engagement release state described above is set, as shown in FIG. 16, the engagement control member 108 is rotated by a lever (not shown) or the like, and the engagement control member 107 is engaged and controlled by the action of the cylindrical cam. Move in a direction 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. 3888960

  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 shaft. I couldn't.

  That is, the coupling mechanism disclosed in Patent Document 1 has a configuration in which one of the coupling pair moves in the axial direction in accordance with the attaching / detaching operation of the attaching / detaching 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. 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 either the engaged state shown in FIG. 15 or the disengaged state shown in FIG.

  For this reason, 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 enable the coupling member to be moved in the axial direction by the attaching / detaching 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 provides a drive transmission device that engages with a unit that can be attached to and detached from an image forming apparatus main body and transmits or disconnects a driving force to the unit. A drive output member that engages with the unit and transmits a drive force, a drive input member, and a drive output member that is movable in the axial direction of the drive output member. An input side engaging member that rotates integrally with the drive input member, an output side that is engageable with the input side engaging member, rotates integrally with the drive output member, and moves integrally in the axial direction An engagement member, an elastic member provided between the drive input member and the input side engagement member, and biasing the input side engagement member toward the output side engagement member; and the output side engagement The inlet in an engagement position engageable with the member; Disengagement position where 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 biasing force of the elastic member And an engagement release member that cuts off transmission of the driving force to the unit, and the input side engagement member is in the engagement position and in the engagement release position. In each, a space is formed that allows the output-side engagement member to move in the axial direction when the drive output member is pressed in the axial direction.

  According to the present invention, the drive output member is allowed to move in the axial direction in either the state where the driving force is released or the state where the driving force is transmitted. Can be moved to.

Sectional drawing which shows the structural example of the image forming apparatus which concerns on Example 1 of this invention. Sectional drawing which shows attachment or detachment of the process cartridge which concerns on Example 1 of this invention. The perspective view explaining 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. The figure explaining operation | movement of the coupling member which concerns on Example 1, 2 of this invention. The perspective view explaining the structure of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing explaining the engagement state of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing explaining the movement of the output shaft in the engagement state of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing explaining the disengagement state of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing explaining the movement of the output shaft in the engagement release state of the clutch mechanism which concerns on Example 1, 2 of this invention. Sectional drawing which shows the structural example of the image forming apparatus which concerns on Example 2 of this invention. Sectional drawing which shows attachment or detachment of the intermediate transfer unit which concerns on Example 2 of this invention. Sectional drawing which shows the separation mechanism of the primary transfer roller which concerns on Example 2 of this invention. The perspective view explaining the structure of the conventional clutch mechanism Sectional drawing explaining the engagement state of the conventional clutch mechanism Sectional drawing explaining the disengagement state of the conventional clutch mechanism

  Hereinafter, exemplary embodiments of the present invention will be described in detail by way of example. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed according to the configuration of the mechanism to which the present invention is applied and various conditions, there are particularly specific descriptions. As long as there is not, it is not the meaning which limits the scope of the present invention only to them.

[Example 1]
FIG. 1 is a cross-sectional view illustrating a configuration example of a drive transmission device having a clutch mechanism and an image forming apparatus including the same according to Embodiment 1 of the present invention. 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 unit includes a photosensitive drum 2 that is an “image carrier”, a developing roller 19 that constitutes a “developing device”, a transfer roller 3 that is a “transfer device”, and the like. In this example, the photosensitive drum 2 is included in the process cartridge 4, and the process cartridge 4 is configured to be replaceable (detachable) by the user with respect to the image forming apparatus 1. The process cartridge includes a charging roller (charging means) (not shown), a cleaning device (cleaning means), etc. in addition to the above-described developing device (developing means) as process means acting on the photosensitive drum 2. It is out.

  The image forming apparatus 1 is provided with a feeding cassette 5 on which sheets S for forming images are stacked. A controller (control unit) 6 controls the rotation of a drive motor (drive source) (not shown), and the feeding roller 7 rotates to separate and feed one sheet, and a plurality of conveying roller pairs 8 and a photoconductor. The drum 2 and the transfer roller 3 are conveyed in this order. The laser scanner 9 for writing an image emits a laser beam L, draws an electrostatic latent image on the surface of the photosensitive drum 2 charged by the charging roller, and is developed on the photosensitive drum 2 by a developing device including the developing roller 19. The toner image is developed. This toner image is transferred to the first surface of the sheet between the photosensitive drum 2 and the transfer roller 3. Thereafter, the sheet is heated and fixed by the fixing device 10 and conveyed in the order of the discharge roller pair 11 and the discharge tray 12.

  In addition, the image forming apparatus 1 is provided with a duplex unit including a reverse conveyance path 13 and a duplex conveyance path 14. A reverse conveyance path 13 branched to another route between the discharge roller pair 11 is provided downstream of the fixing device 10. The branch section has a path switching means 15 and is driven by a drive source (not shown). In the reverse conveyance path 13, a reverse conveyance roller pair 16 capable of normal rotation and reverse rotation is provided to reversely convey the sheet. When image formation is performed on both sides of the sheet, image formation on the first surface is performed. The sheet after finishing is conveyed reversely and sent to the duplex conveying path 14. Thereafter, in a state where the first surface and the second surface of the sheet are reversed, the sheet is fed again to the image forming unit by the plurality of conveying roller pairs 17. The subsequent operation is the same as that of the first surface.

  When the user replaces the process cartridge 4, the opening / closing cover 18 of the image forming apparatus 1 is opened as shown in FIG. 2. The drawing direction and mounting direction of the process cartridge 4 are directions substantially orthogonal to the axial direction of the photosensitive drum 2 and the drive input shaft for inputting drive to the process cartridge, as indicated by arrows in FIG.

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

  A coupling configuration in this embodiment will be described with reference to FIG. In FIG. 3, an example of the coupling shape in a present Example is shown. The shape shown in FIG. 3 is a known technique disclosed in Patent Document 1, and is not limited to this shape, and any shape having similar effects and operations may be used.

  The pair 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 a coupling that is provided in the apparatus main body of the image forming apparatus 1 and is rotated by power from a drive source. The drive coupling 20 has a later-described clutch member on the same axis. The driven coupling 21 is provided in the process cartridge 4 that is a unit that can be attached to and detached from the apparatus main body, and is a coupling that rotates in mesh with the driving coupling 20. The image forming apparatus according to the present exemplary embodiment has a configuration in which a single motor (drive source) drives not only the process cartridge but also a feeding mechanism and each conveyance roller.

  The coupling operation when the process cartridge is mounted will be described with reference to FIG. FIG. 4 is a view of a state immediately before the process cartridge 4 is inserted into the apparatus main body and the couplings 20 and 21 are engaged, as viewed from a direction orthogonal to the coupling axis. FIG. 4 illustrates a set of couplings for the sake of simplicity. In this embodiment, the process cartridge 4 is inserted in the direction of the arrow 25. Then, when the coupling meshes, the taper surface 22 on the outer periphery of the drive coupling 20 and the taper surface 23 of the driven coupling 21 come into contact with each other, and the drive coupling 20 receives the force and the arrow 24 substantially orthogonal to the direction of the arrow 25. Move in the direction (axial direction). Therefore, the couplings 20 and 21 can be engaged. Note that at least one of the tapered surfaces 22 and 23 at the tip (outer periphery) of each coupling is not limited to an inclined surface, and 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 cross-sectional view of the state in which the coupling is engaged, as viewed from a direction orthogonal to the coupling axis. FIG. 5 also shows a set of couplings in a simplified manner for the sake of explanation, as in FIG. In this embodiment, the process cartridge 4 is detached in the direction of the arrow 26. Then, the taper surface 28 of the inner periphery of the drive coupling 20 and the taper surface 22 of the driven coupling 21 come into contact with each other, and the drive coupling 20 receives the force and the direction of the arrow 27 (axial direction) substantially orthogonal to the direction of the arrow 26. Move to). Therefore, the couplings 20 and 21 are disengaged and can be detached. The tapered surface 28 at the tip (inner circumference) of the coupling is not limited to the inclined surface, and may be a curved surface such as a part of a spherical surface.

  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 that engages with the convex shape. Is not to be done. In order to achieve the above operation, the shapes of the driving coupling 20 and the driven coupling 21 may be interchanged, and the concave and convex shapes may be reversed. That is, the tip of the drive coupling on the apparatus main body side may be convex, and the tip of the driven coupling on the process cartridge side may be concave to engage 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 and coaxial with the coupling 20 that transmits driving to the developing roller 19. By providing the clutch mechanism, the driving force can be cut off during the time when the rotation is unnecessary. Thereby, it is possible to protect various developing devices including toner and developing roller contained in the process cartridge 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 the present 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, parallel pins 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 protrusion 33 a that meshes with a groove provided in the drive input gear 31. The input side engaging member 33 rotates integrally with the drive input gear 31 by the protrusion 33 a meshing with the groove of the drive input gear 31. Further, the input side engaging member 33 has a region movable in the axial direction. Further, since the spring 32 also rotates integrally with the drive input gear 31, the spring end portion does not rotate and slide. The output shaft 34 is a drive output member, and has a drive coupling 20 that engages with the driven coupling 21 (see FIG. 3) on the process cartridge side at one end. 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 engaging member 35 rotates integrally with the output shaft 34. The parallel pin 36 fixes the drive output side engaging member 35 to the output shaft 34. As a result, the output shaft 34 and the drive output side engaging member 35 are integrated in the axial direction and rotate integrally around the output shaft 34. The bearing 39 is a bearing member, supports the engagement control member 37 while being movable in the axial direction and restricting rotation, supports the engagement control member 38 rotatably, and is attached to 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, and engage or disengage the output side engagement member 35. Is a disengagement member that controls (switches) and includes a cylindrical cam 37a and a cylindrical cam 38a.

  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. When engaging, the engagement control member 38 is rotated by a lever (not shown) or the like so that 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 and engaged with the output side engaging member 35. The At this time, the drive input gear 31 is biased toward the other side in the axial direction by the elastic force of the spring 32 and abuts against the contact surface 34 b of the output shaft 34. At this time, it can be said that the input side engaging member 33 is in an engaging position where it can engage with the drive output side engaging member 35.

  In this engaged state, as shown in FIG. 7, the engagement control member 37 abuts on the input side engagement member 33, and the shaft of the output shaft 34 is 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 biasing force of the spring 32 and presses the output shaft 34 in the direction of the arrow 43. . Then, the e-ring 34a hits the bearing 39 in the axial direction. As a result, the axial position of the output shaft 34 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. Note that the output shaft 34 is not necessarily pressed in the direction of the arrow 43 by the biasing force of the spring 32. That is, in the engaged state of the input side engagement member 33 and the drive output side engagement member 35, the engagement control member 37 does not contact the input side engagement member 33, and the biasing member other than the spring 32 is used. The output shaft 34 may be pressed in the direction of the 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 output shaft 34 is allowed to move in the axial direction. Further, a space B different from the space A allowing the output shaft 34 to move in the axial direction is provided between the input side engaging member 33 and the drive input gear 31. The space B allows the drive input gear 31 to move in the axial direction and approaches the input side engaging member 33, and allows the drive input gear 31 to move in the axial direction, resulting in an output shaft. 34 is allowed to move in the axial direction.

  FIG. 8 shows an operation in the case where the process cartridge is attached and detached in a direction substantially perpendicular to the drive shaft (in the direction of the arrow 25 in FIG. 4) in the above-described engaged state. As described above, when the process cartridge is attached or detached, the coupling 20 on the apparatus main body side is pushed by a predetermined amount toward the frame member 40 (in the direction of arrow 41) by the coupling on the process cartridge side. As a result, the output shaft 34 is pressed toward one side (in the direction of the arrow 41) of the above-mentioned axial direction, and the output side fixed to the output shaft 34 by the parallel pin 36 and the drive input gear 31 pressed by the contact surface 34b. Both the engaging members 35 move in the arrow 41 direction. The drive input gear 31 moves in the direction of the arrow 41 against the biasing force of the spring 32. On the other hand, the input side engagement member 33 that is 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 engagement member 33 is compressed. Here, as shown in FIG. 7, in this configuration, there is a space A that allows the output shaft 34 to move in the axial direction between the output side engagement member 35 and the bearing 39. It is possible to move in the axial direction of the output shaft 34 in the range of.

  When the pressing in the direction of arrow 41 of the coupling 20 on the apparatus main body side by the coupling on the process cartridge side is released, the drive input gear 31 presses the contact surface 34b by the biasing force of the spring 32, and the output shaft 34 is moved. 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.

  Further, adopting the above configuration can utilize the spring 32 that biases the input side engagement member 33 as a biasing force for resisting the movement of the output shaft 34 and returning it to the original state. The above operation can be realized without adding an urging member. In addition, the structure which presses the output shaft 34 in the direction of the arrow 43 (FIG. 7) with a new urging | biasing member may be sufficient. Even in such a configuration, since the biasing force of the spring 32 can be used as the biasing force for returning to the original state, the biasing force of the new biasing member is compared with the case where the biasing force of the spring 32 is not used at all. Can be reduced accordingly. Further, since it is built in the clutch mechanism, it is advantageous in terms of noise and wear that there is no rotating sliding part with other members. After the process cartridge is attached / detached, the output shaft 34 is urged and moved in the direction opposite to the one side in the axial direction so that the 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. When releasing the engagement, the engagement control member 38 is rotated by a lever (not shown) or the like, 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. Move to 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 in 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 the amount of movement of the input side engaging member 33. That is, the engagement control member 37 moves the input side engagement member 33 from the engagement position to the engagement release position against the biasing force of the spring 32 (by compressing the spring 32).

  In this disengaged state, as shown in FIG. 9, the engagement control member 37 contacts the input side engagement member 33, and the output shaft 34 is 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 hits the bearing 39 in the axial direction. As a result, the axial position of the output shaft 34 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 allowing the output shaft 34 to move in the axial direction is provided between the input side engaging member 33 and the drive input gear 31. The space B allows the drive input gear 31 to move in the axial direction and approaches the input side engaging member 33, and allows the drive input gear 31 to move in the axial direction, resulting in an output shaft. 34 is allowed to move in the axial direction.

  FIG. 10 shows an operation in the case where the process cartridge is attached and detached in the direction substantially perpendicular to the drive shaft (the direction of the arrow 25 in FIG. 4) in the above-described disengaged state. As described above, when the process cartridge is attached or detached, the coupling 20 on the apparatus main body side is pushed by a predetermined amount toward the frame member 40 (in the direction of the arrow 42) by the coupling on the process cartridge side. As a result, the output shaft 34 is pressed toward one side (in the direction of the arrow 42) of the above-mentioned axial direction, and the output side fixed to the output shaft 34 by the parallel pin 36 and the drive input gear 31 pressed by the contact surface 34b. Both the engaging members 35 move 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 engagement 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 engagement member 33 is further compressed. Here, as shown in FIG. 9, in this 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, respectively, in the axial direction of the output shaft 34. The spaces A and B that allow the movement of are provided. 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 34b by the biasing force of the spring 32, and the output shaft 34 is moved. 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.

  Further, adopting the above configuration can utilize the spring 32 that biases the input side engagement member 33 as a biasing force for resisting the movement of the output shaft 34 and returning it to the original state. The above operation can be realized without adding an urging member. In addition, the structure which presses the output shaft 34 in the direction of the arrow 44 (FIG. 9) with a new urging | biasing member may be sufficient. Even in such a configuration, since the biasing force of the spring 32 can be used as the biasing force for returning to the original state, the biasing force of the new biasing member is compared with the case where the biasing force of the spring 32 is not used at all. Can be reduced accordingly. Further, since it is built in the clutch mechanism, it is advantageous in terms of noise and wear that there is no rotating sliding part with other members. After the process cartridge is attached and detached, the output shaft 34 is urged and moved in the direction opposite to the one side in the axial direction 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 engagement of the clutches (engagement members 33 and 35) and release the drive to the developing unit at the end timing of the image forming operation. Therefore, the process cartridge is normally replaced in a state where the clutch (engagement members 33 and 35) is disengaged.

  However, there is a possibility that the image forming apparatus stops with the clutch (engagement members 33, 35) engaged and the process cartridge is attached or detached for some reason such as the power being cut off. In this example, the process cartridge can be attached and detached because of the above-described configuration, since the output shaft 34 can be allowed to move in the axial direction even when the clutch (engaging members 33 and 35) is engaged.

  As described above, according to the present embodiment, since the movement of the output shaft 34 in the axial direction is allowed in either the state where the driving force is released or the state where the driving force is transmitted, the process cartridge can be attached and detached. 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 a second embodiment of the present invention and an image forming apparatus including the drive transmission device. The clutch mechanism in the drive transmission device is the same as that described in the first embodiment. The same configurations and effects as those of the first embodiment are appropriately omitted by using the same reference numerals.

  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, four process cartridges that perform image formation are provided inside the image forming apparatus 50. Each process cartridge includes photosensitive drums 2a, 2b, 2c, and 2d that are “image carriers”, 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 replaceable (detachable) by the user with respect to the apparatus main body of the image forming apparatus 50. These four process cartridges 51a, 51b, 51c, and 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 electrostatic latent images 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 photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary transferred onto the surface of the intermediate transfer belt 53 sequentially. The intermediate transfer unit 56 mainly includes an intermediate transfer belt 53 as an intermediate transfer member, a driving roller 57, a driven roller 58, four primary transfer rollers 59a, 59b, 59c and 59d as primary transfer means, a cleaning means 60, It comprises 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 an urging means (not shown), and applies a predetermined tension to the intermediate transfer belt 53. The primary transfer rollers 59a, 59b, 59c, and 59d are disposed inside the intermediate transfer belt 53 so as to face the photosensitive drums 2a, 2b, 2c, and 2d, and are each urged by a biasing member (not shown). It is biased toward the photosensitive drum side.

  The transfer of the toner image onto the sheet S is performed by the secondary transfer unit 54 after 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 conveys it 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 onto 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 this 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 the direction indicated by the arrow. The drawing-out direction and the mounting direction of the intermediate transfer unit 56 are directions substantially orthogonal to the axial direction of the photosensitive drum 2 and the drive input shaft that inputs driving to the intermediate transfer unit 56.

  The intermediate transfer unit 56 has primary transfer roller separation means corresponding to Y, M, and C that are in contact with the photosensitive drums via the intermediate transfer belt 53 during color image formation. This is to prevent sliding with a photosensitive drum that is not used during monochrome image formation and to prolong the life of the photosensitive drum.

  FIG. 13 shows an example of the primary transfer separation means in the present embodiment, and is a view showing a cross section in the axial direction of the photosensitive drum. The primary transfer separation means is mainly composed of a cam 63 and a slide member 62, and one set is provided on both ends in the axial direction of the transfer roller. As the cam 63 rotates and the slide member 62 moves left and right (in the direction of the arrow), the contact / separation positions of the primary transfer rollers 59a, 59b, and 59c with respect to the respective photosensitive drums can be controlled. 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. A drive coupling 20 is provided on the apparatus main body side, and a 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, the apparatus main body on the drive shaft of the cam 63 has a clutch mechanism shown in FIGS. The operation of the coupling and the clutch mechanism when attaching / detaching the intermediate transfer unit is the same as the operation 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, the movement of the output shaft in the axial direction is allowed in either the state where the driving force is released or the state where the driving force is transmitted. The coupling can be moved in the axial direction. Thereby, the intermediate transfer unit can be detached from the apparatus main body regardless of the engaged / disengaged state of the clutch mechanism.

[Other Examples]
In the above-described embodiments, the process cartridge and the intermediate transfer unit are exemplified as the unit that can be attached to and detached from the image forming apparatus main body. However, the present invention is not limited to this. 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. The same applies to the image forming apparatus to which the unit can be attached and detached. Can be expected. Further, as the process cartridge which is a detachable unit, a process cartridge having a photosensitive drum and a charging unit, a developing unit, and a cleaning unit as a process unit acting on the photosensitive drum are illustrated, but the process cartridge is limited to this. is not. In addition to the photosensitive drum, a process cartridge that integrally includes any one of a charging unit, a developing unit, and a cleaning unit may be used.

  In the above-described embodiments, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. In these image forming apparatuses in which the unit can be attached and detached, the same effect can be obtained by applying the present invention to a drive transmission apparatus that transmits a driving force to the unit. In the above-described embodiments, the image forming apparatus in which the unit having the belt (intermediate transfer member) that carries the image to be transferred to the sheet is detachable is illustrated, but the present invention is not limited to this. The image forming apparatus may be a detachable unit having a conveyance belt that carries and conveys a sheet. In this image forming apparatus, the same effect can be obtained by applying the present invention to a drive transmission device that transmits a driving force to the unit.

DESCRIPTION OF SYMBOLS 1,50 ... Image forming apparatus 2 ... Photosensitive drum 4 ... Process cartridge 19 ... Developing roller 20, 21 ... Driven coupling 22, 23, 28 ... Tapered surface 31 ... Drive input gear 32 ... Spring 33 ... Input side engagement Member 33a ... Projection 34 ... Output shaft 35 ... Drive output side engagement 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 to transmit or cut a driving force to the unit,
A drive output member that includes a coupling engageable with the unit and that transmits the driving force by engaging with the unit;
A drive input member;
An input-side engagement member provided so as to be movable in the axial direction of the drive output member with respect to the drive output member, and rotating 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, and biasing the input side engaging member toward the output side engaging member;
The input side engagement member is moved in the axial direction against the urging force of the elastic member by moving the input side engagement member in an engagement position engageable with the output side engagement member. An engagement release member that moves to a disengagement position where the engagement with the output side engagement member is released, and cuts off transmission of the driving force to the unit;
Have
In each of the state in which the input side engaging member is in the engaging position and the state in the disengaging position, the output side engaging member is moved to the shaft when the drive output member is pressed in the axial direction. A drive transmission device characterized in that a space allowing movement in a direction is formed.   In each of the state where the input-side engagement member is in the engagement position and the engagement release position, the drive input member is moved in the axial direction when the drive output member is pressed in the axial direction. The drive transmission device according to claim 1, wherein a space that allows the movement of the space is formed.   When the drive output member is pressed in the axial direction when the input side engagement member is in the engagement position and in the engagement release position, the drive input member is the drive output member. The drive transmission device according to claim 1, wherein the drive transmission device moves in the axial direction against the urging force of the elastic member.   When the drive output member is pressed in the axial direction in each of the state in which the input side engagement member is in the engagement position and the state in the engagement release position, 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 away from the input-side engagement member.   A bearing member that supports the drive output member so as to be rotatable and axially movable with respect to a frame member of the image forming apparatus main body, and the space is defined between the output side engaging member and the bearing member; The drive transmission device according to any one of claims 1 to 4, wherein the drive transmission device is provided.   The drive transmission device according to any one of claims 1 to 5, wherein the elastic member rotates integrally with the drive input member.   The drive transmission device according to claim 1, wherein the elastic member is a compression spring.   The drive transmission device according to any one of claims 1 to 7, wherein the coupling of the drive output member has an inclined surface or a curved surface at a distal end portion engaged 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 tip end portion engaged with the unit.   The drive transmission device according to claim 8, wherein the coupling of the drive output member has a concave shape at a tip end portion engaged with the unit. An image forming apparatus having 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