JP2014059383A - Drive transmission mechanism and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly perform disengagement of a movement side gear in a drive transmission mechanism formed of a drive gear and a driven gear that can be contacted and separated.SOLUTION: A drive transmission mechanism causes a drive gear 80 and a driven gear 70 to be contacted and separated to transmit and block driving force from the drive gear 80 to the driven gear 70. Between shafts of the drive gear 80 and the driven gear 70, an inter-shaft regulating member 90 is disposed for regulating an inter-shaft distance of both shafts when the gears are engaged with each other. On the inter-shaft regulating member 90, a guide groove 91 is formed for a shaft 70a of one gear 70 to come and go upon contact and separation of both gears, the shaft 70a of the one gear 70 being movable for contact and separation of both gears. An elastic member 92 is provided urging means for urging the movable gear to the deep side of the guide groove 91.

Description

  The present invention relates to a drive transmission mechanism in which one of two gears rotating while meshing with each other is movably supported so as to contact and separate from the other. The present invention also relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer equipped with such a drive transmission mechanism.

  Conventionally, in a drive transmission mechanism that transmits a driving force from a driving side to a driven side by rotating the driving gear and the driven gear while meshing with each other, one of the gears is supported so as to be movable with respect to the other gear. Are known. For example, in an image forming apparatus, in a main body of an image forming apparatus to which a motor as a driving source is fixed, a driven unit provided with a driven body such as a photosensitive member and a developing device can be attached and detached. There is one that supports the drive unit so as to be movable with respect to the apparatus main body.

  In this image forming apparatus, with the movement of the driven body unit, the driven gear provided in the driven body unit and the driving gear provided in the image forming apparatus main body are brought into and out of contact with each other. In addition, as in the image forming apparatus of Patent Document 1, there is a type in which a cover on which a driven body such as a pair of paper transport rollers is mounted can be opened and closed with respect to an image forming apparatus main body to which a motor is fixed. In this image forming apparatus, as the cover is opened and closed, the driven gear provided on the cover and the driving gear provided on the image forming apparatus main body are brought into contact with and separated from each other.

  In these image forming apparatuses, at the meshing position where the driving gear and the driven gear are in contact with each other and rotating, the force that causes the driving gear to bite more strongly by the reaction of the rotation. On the other hand, a force to move away from the driving gear acts.

  For this reason, in the drive transmission mechanism that is linked to the opening and closing of the cover of the image forming apparatus, the positional relationship between the drive gear on the main body side and the driven gear on the cover side is regulated by the meshing position of both gears. It is already known to arrange an inter-axis regulating member with a guide groove to regulate (see Patent Document 2-5).

  In such a drive transmission mechanism, in order to smoothly separate the driven gear from the drive gear, or to disengage the drive gear from the driven gear, on the contrary, in general, the gear on the moving side is The support has a certain amount of backlash. However, a large tooth pressure (contact pressure) at the time of drive transmission often remains between the meshing tooth surfaces of the drive gear and the driven gear even after the drive gear is stopped.

  If the driven gear is to be detached from the drive gear with such a large tooth pressure remaining, for example, the separation resistance of the driven gear is large due to the frictional resistance caused by the tooth pressure. In addition, the toothed surface of the drive gear is located in the direction of detachment of the toothed surface of the driven gear, obstructing the separation, and the driven gear cannot be extracted from the guide groove of the inter-axis regulating member unless the drive gear is rotated in the opposite direction to some extent. In some cases. As described above, in the conventional drive transmission mechanism using the inter-axis regulating member, when the gear is disengaged, there is a problem that the gear on the moving side does not easily come out of the guide groove of the inter-axis regulating member due to the meshing of the gear tooth surfaces. there were.

  In view of the above problems, an object of the present invention is to enable a gear to be smoothly detached in a drive transmission mechanism using an inter-axis regulating member.

  In order to solve the above problems, the present invention provides a drive transmission mechanism in which the drive gear and the driven gear are brought into contact with and separated from each other to transmit and block the drive force from the drive gear to the driven gear. Between the two shafts of the driven gear and the driven gear, an inter-axis restricting member for restricting the distance between the shafts when the gears are engaged is arranged, and the inter-shaft restricting member can be moved to contact and separate the two gears. The shaft of one of the gears forms a guide groove that enters and exits when the two gears are brought into and out of contact with each other, and is provided with a biasing means that biases the movable gear toward the back side of the guide groove. This is a featured drive transmission mechanism.

  According to the present invention, the biasing means for biasing the moving gear toward the back side of the guide groove is provided, so that the contact pressure between the tooth surfaces of the drive gear and the driven gear is reduced by the biasing force of the biasing means. This makes it possible to smoothly disengage the moving gear from the counterpart gear.

1 is a cross-sectional view illustrating an internal structure of an image forming apparatus according to an embodiment of the present invention. It is a perspective view inside a transfer cover. It is a disassembled perspective view of the inner side of a transfer cover. It is a side view of the drive transmission mechanism at the time of gear meshing. It is a side view of the drive transmission mechanism at the time of gear disengagement. It is an enlarged side view which shows the meshing state of a drive gear and a driven gear. FIG. 5B is a view similar to FIG. 5A when the drive gear is rotated in the reverse direction. (A) and (b) are the front views and side views which show the modification of a drive gear. It is a side view which shows the modification of a drive transmission mechanism. It is a side view which shows the modification of a drive transmission mechanism. It is a side view which shows the modification of a drive transmission mechanism.

  Hereinafter, an image forming apparatus including a sheet conveying device according to an embodiment of the present invention will be described with reference to the drawings.

(Image forming device)
FIG. 1 is an external perspective view of a laser printer as an image forming apparatus provided with a sheet conveying device according to an embodiment of the present invention. The image forming apparatus to which the paper conveying apparatus according to the present invention is applied may be a copying machine, a printer, or a facsimile machine, or may be a complex machine that combines two or more of these. A paper feed tray 30 is disposed at the lower part of the image forming apparatus, and a transfer cover 8 serving as an internal inspection cover is disposed on the outer surface of the image forming apparatus on the upper side of the paper feed tray 30. A paper discharge tray 44 is disposed at the top of the apparatus.

  The transfer cover 8 includes a double-side unit 9 on the inner surface thereof, and is rotatable to the front side of the image forming apparatus about a rotation shaft 12 disposed at the lower part of the apparatus. 2 and 3 show the structure of the transfer cover. In the figure, 102 is a first reverse conveying roller, 104 is a second reverse conveying roller, 110 is a manual feed roller, 113 is a second gear, 114 is a relay rotating member, 116 is a driving side V belt, and 121 is a rotating shaft 121a. , A conveyance guide plate that can rotate around the center, 128 a dual-purpose roller gear, 129 a paper feed roller gear, and 120 a second reverse conveyance pulley. The second gear 113 is engaged with a first gear (not shown) provided on the image forming apparatus main body side so as to receive driving force from the image forming apparatus body side and transmit driving to various rotating members in the transfer cover 8. It is configured. The embodiment of the drive transmission mechanism of the present invention is applied to the first gear and the second gear 113 as described later.

  The duplex unit 9 has a transport housing 9a, and a paper return path 9b is formed on the back side of the transport housing 9a. Further, the inner surface side of the transport housing 9 a constitutes a part of the sheet transport path on the main body side, and includes a secondary transfer roller 20 as a transfer member and one timing driving roller 32 a of the timing roller pair 32. . The secondary transfer roller 20 constitutes a pair of transfer rollers as a pair of feeding members with a drive roller 18 on the main body side to be described later, and the pair of timing drive rollers 32a with a timing driven roller 32b on the main body side. The timing roller pair 32 is configured as a feed member.

  The main part of the image forming apparatus will be described below with reference to FIG. The image forming apparatus includes four process units 1K, 1Y, 1M, and 1C as image forming units that form images with developers of black, yellow, magenta, and cyan corresponding to color separation components of a color image. .

  Process units 1K, 1Y, 1M, and 1C are disposed on the main body side of the image forming apparatus. Each process unit 1K, 1Y, 1M, 1C has toner bottles 6K, 6Y, 6M, 6C containing unused toners of different colors. Other than that, the configuration is the same. The structure of one process unit 1K will be described as an example. The process unit 1K includes an image carrier 2K (photosensitive drum), a drum cleaning device 3K, a static eliminator (not shown), a charging device 4K, a developing device 5K, and the like. Have. The process unit 1K is detachably attached to the main body of the image forming apparatus so that consumable parts can be replaced at a time.

  An exposure unit 7 is disposed above each process unit 1K, 1Y, 1M, 1C. The exposure device 7 is configured to emit laser light from a laser diode based on image data.

  A transfer device 15 serving as a first transfer unit is disposed below each process unit 1K, 1Y, 1M, 1C. The transfer device 15 includes four primary transfer rollers 19K, 19Y, 19M, and 19C facing each image carrier 2K, 2Y, 2M, and 2C, each primary transfer roller 19K, 19Y, 19M, and 19C, a driving roller 18, and a driven roller. 17 includes an intermediate transfer belt 16 that circulates around 17, a secondary transfer roller 20 as a second transfer unit disposed opposite to the driving roller 18, a belt cleaning device 21, a cleaning backup roller 22, and the like. If the image carriers 2K, 2Y, 2M, and 2C are the first image carriers of the respective colors, the intermediate transfer belt 16 is a second image carrier that combines these images.

  At the bottom of the image forming apparatus, there are provided a paper feed tray 30 that can accommodate a large number of paper P and a paper feed roller 30 a that feeds the paper P from the paper feed tray 30 toward the paper feed path 31. Near the end of the paper feed path 31, a timing roller pair 32 for temporarily stopping the paper is provided. The timing roller pair 32 is located immediately upstream of the intermediate transfer belt 16, and in order to accurately align the toner image on the intermediate transfer belt 16 and the leading edge position of the sheet, the sheet P is once slackened to perform intermediate transfer. Immediately before the toner image formed on the belt 16 is transferred to the paper P at the secondary transfer nip portion, the paper P is sent to the secondary transfer nip portion at a predetermined timing.

  A post-transfer conveyance path 33 is disposed above the nip portion between the secondary transfer roller 20 and the driving roller 18. Near the end of the post-transfer conveyance path 33, a fixing device 34 as a fixing unit is provided. The fixing device 34 includes a fixing roller 34a containing a heat source such as a halogen lamp (not shown), and a pressure roller 34b that rotates while contacting the fixing roller 34a with a predetermined pressure.

  A post-fixing conveyance path 35 is disposed above the fixing device 34, and branches to a paper discharge path 36 and a reverse conveyance path 41 at the end of the post-fixing conveyance path 35. A switching member 42 that swings around a swing shaft 42a is disposed on the side of the post-fixing conveyance path 35. A paper discharge roller pair 37 is disposed at the end of the paper discharge path 36. The reverse conveyance path 41 joins the paper feed path 31 at the end thereof, and a reverse conveyance roller pair 43 is disposed in the middle of the reverse conveyance path 41. A paper discharge tray 44 having an upper cover recessed inward is disposed at the top of the image forming apparatus.

  A powder container 10 (toner container) for storing waste toner is disposed between the transfer device 15 and the paper feed tray 30. The powder container 10 is detachably attached to the image forming apparatus main body.

  In the image forming apparatus of this embodiment, the space from the paper feed roller 30a to the secondary transfer roller 20 needs to be separated to some extent due to the transfer paper transfer relationship. For this purpose, the powder container 10 is installed in the dead space generated to reduce the size of the entire image forming apparatus.

(Operation of image forming apparatus)
Next, the basic operation of this image forming apparatus will be described. In FIG. 1, when a paper feed roller 30 a is rotated by a paper feed signal from a control unit of an image forming apparatus (not shown), only the topmost paper P stacked on the paper feed tray 30 is separated and fed to the paper feed path 31. Sent out. When the leading edge of the paper P reaches the nip portion of the timing roller pair 32, the timing is synchronized with the toner image formed on the intermediate transfer belt 16, and the paper P is slackened to correct the skew of the leading edge of the paper P. Wait in the state of forming.

  The image forming operation will be described by taking one process unit 1K as an example. First, the charging device 4K charges the surface of the image carrier 2K to a uniform high potential. Based on the image data, the exposure device 7 irradiates the surface of the image carrier 2K with the laser beam L, and the potential of the irradiated portion is lowered to form an electrostatic latent image. Unused black toner is supplied from the toner bottle 6K to the developing device 5K.

  The toner is transferred to the surface portion of the image carrier 2K on which the electrostatic latent image is formed by the developing device 5K, and a black toner image is formed (developed). Then, the toner image formed on the image carrier 2K is transferred to the intermediate transfer belt 16.

  The drum cleaning device 3K removes residual toner adhering to the surface of the image carrier 2K after the intermediate transfer process. The removed residual toner is sent to a waste toner container in the process unit 1K and collected by a waste toner transport unit (not shown). Further, a static elimination device (not shown) neutralizes residual charges on the image carrier 2K after cleaning.

  In the process units 1Y, 1M, and 1C for the respective colors, toner images are similarly formed on the image carriers 2Y, 2M, and 2C, and the respective color toner images are transferred to the intermediate transfer belt 16 so as to overlap each other.

  When the color toner images are transferred to the intermediate transfer belt 16 so as to overlap each other, the timing roller pair 32 and the paper feed roller 30a start driving, and take timing (synchronization) with the toner image superimposed and transferred to the intermediate transfer belt 16. The paper P is sent to the secondary transfer roller 20. Then, the toner image on the intermediate transfer belt 16 is transferred to the fed paper P by the secondary transfer nip portion of the secondary transfer roller 20.

  The paper P to which the toner image has been transferred is conveyed to the fixing device 34 through the post-transfer conveyance path 33. The paper P sent to the fixing device 34 is sandwiched between the fixing roller 34a and the pressure roller 34b, and the unfixed toner image is heated and pressed to be fixed on the paper P. The sheet P on which the toner image is fixed is sent out from the fixing device 34 to the post-fixing conveyance path 35.

  At the timing when the paper P is sent out from the fixing device 34, the switching member 42 is at the position indicated by the solid line in FIG. 1 and opens near the end of the post-fixing conveyance path 35. The paper P sent out from the fixing device 34 passes through the post-fixing conveyance path 35, is sandwiched between the paper discharge roller pair 37, and is discharged to the paper discharge tray 44.

  When performing duplex printing, when the trailing edge of the paper P conveyed by the paper discharge roller pair 37 passes through the post-fixing conveyance path 35, the switching member 42 swings to the position indicated by the dotted line in FIG. The vicinity of the end of the path 35 is closed. At substantially the same time, the paper discharge roller pair 37 rotates in the reverse direction, and the paper P is fed back and enters the reverse conveyance path 41.

  The sheet P transported in the reverse transport path 41 passes through the reverse transport roller pair 43, reaches the timing roller pair 32, and is sent out in synchronism with the toner image for the back surface formed on the intermediate transfer belt 16. A toner image is transferred to the back surface of the paper P when passing through the secondary transfer roller 20. After the toner image on the back surface of the paper P is fixed by the fixing device 34, the toner image is discharged to the paper discharge tray 44 through the post-fixing conveyance path 35, the paper discharge path 36, and the paper discharge roller pair 37 in order.

  Further, after the toner image on the intermediate transfer belt 16 is transferred to the paper P, residual toner adheres on the intermediate transfer belt 16. This residual toner is removed from the intermediate transfer belt 16 by the belt cleaning device 21.

  The toner removed from the intermediate transfer belt 16 is transported to the inlet 53 of the powder container 10 by a waste toner transport unit (not shown) and collected in the powder container 10.

(Transfer cover)
When a jam occurs due to a paper jam during printing, the user can manually open the transfer cover 8 around the rotation shaft 12 and take out the jammed paper. When the paper P is sandwiched between the timing roller pair 32, the pressure of the timing roller pair 32 is very high, so that it is difficult to take out jammed paper while the timing roller pair 32 is closed.

  In this embodiment, the transfer roller 20 and one timing driving roller 32a of the timing roller pair 32 are disposed inside the transfer cover 8, respectively. The roller pair 32 can also be opened at the same time, and jamming can be performed quickly and easily. That is, when the transfer cover 8 is released to the front side with the rotary shaft 12 as the center, the fixing device 34, the end of the intermediate transfer belt 16, the timing driven roller 32b, and the like can be seen inside, so that the internal jam processing is easy. is there.

(Drive transmission mechanism)
FIGS. 4A and 4B show an embodiment of the drive transmission mechanism of the present invention, and are conceptual diagrams used for drive transmission to the second gear 113 of the transfer cover 8 of FIGS. In the figure, the transfer cover 8 of FIGS. 1 to 3 is simplified. As described above, the transfer cover 8 is supported so as to be swingable in the left-right direction with respect to the image forming apparatus main body about the shaft 12. The transfer cover 8 constitutes the main arm of the drive transmission mechanism, and in the following description, the transfer cover 8 will be referred to as the main arm 8 as necessary.

  A sub arm 60 is swingably supported around the shaft 8a on the distal end side of the main arm 8. An elastic member 92 as an urging means is disposed between the main arm 8 and the sub arm 60. The sub arm 60 is urged clockwise by the elastic member 92. In this embodiment, the main arm 8 and the sub arm 60 are collectively referred to as a swing arm.

  The sub arm 60 extends toward the apparatus main body in FIG. 1, and a driven gear 70 is attached to the tip of the sub arm 60 so as to be rotatable about a shaft 70a. The driven gear 70 corresponds to the second gear 113 shown in FIGS.

  A drive gear 80 is disposed on the left side of the main arm 8 (on the main body side of the image forming apparatus in FIG. 1) so as to be rotatable about a shaft 80a. The drive gear 80 corresponds to the first gear on the main body side that makes a pair with the second gear 113 described above.

  An inter-axis regulating member 90 is fixedly disposed so as to surround the shaft 80 a of the drive gear 80. The inter-axis regulating member 90 is plate-shaped and has a guide groove 91 whose back side is a dead end. The inner side of the guide groove 91 is an inter-axis restriction region. The guide groove 91 has an inner circular arc portion 91 a and an outer circular arc portion 91 b centering on the shaft 80 a of the drive gear 80. The distance between the inner circular arc portion 91 a and the outer circular arc portion 91 b is slightly larger than the diameter of the shaft 70 a of the driven gear 70. In addition, an inclined portion 91c that is inclined in a direction away from the shaft 80a of the drive gear 80 is formed from the inlet-side end portion of the inner arc portion 91a.

  When the main arm 8 is rotated to the closed position as shown in FIG. 4A when the drive gear 80 and the driven gear 70 are connected, the shaft 70a of the driven gear 70 enters the guide groove 91 of the inter-axis regulating member 90. At this time, the shaft 70 a is guided by the inclined portion 91 c on the inlet side of the guide groove 91. Since the shaft 70a is swingably supported by the swing arms (the main arm 8 and the sub arm 60), the insertion into the guide groove 91 is smooth.

  Further, when the shaft 70a enters the guide groove 91, the sub arm 60 swings with respect to the main arm 8, so that the elastic member 92 is slightly compressed. For this reason, the sub arm 60 is urged clockwise in FIG. 4A. As a result, the shaft 70a is biased toward the back side of the guide groove 91, and the main arm 8, that is, the cover 8 is biased in the closing direction (leftward).

  With the shaft 70a completely in the guide groove 91, the teeth of the drive gear 80 and the driven gear 70 mesh with each other. In this engaged state, the distance between the shafts 80 a and 70 a of the drive gear 80 and the driven gear 70 is regulated by the guide groove 91 of the inter-axis regulating member 90. That is, the movement of the shaft 70 a of the driven gear 70 that has entered the guide groove 91 in the direction in which the space between the shafts is enlarged is restricted by the outer circular arc portion 91 b of the guide groove 91. Similarly, the movement in the direction of reducing the distance between the axes is restricted by the inner circular arc portion 91a. As a result, the two gears are securely connected to each other as shown in FIG. 5A.

  When the drive gear 80 is driven counterclockwise in this state, the driven gear 70 is driven clockwise, and the driving force is transmitted to the various rotating members in the transfer cover 8 of FIGS. At this time, the tooth surfaces of the drive gear 80 and the driven gear 70 come into contact with each other with a strong force, and the shaft 70 a of the driven gear 70 is pushed to the back side of the guide groove 91.

  For this reason, even if driving of the drive gear 80 is stopped, a large tooth pressure (contact pressure) often remains between the two gears. Even if the main arm 8 is rotated to the open side, that is, the right side in this state, the tooth surface of the drive gear 80 becomes a wall, and the driven gear 70 cannot be smoothly detached from the guide groove 91. That is, it is difficult to open the transfer cover 8.

  However, since the elastic member 92 is provided in this embodiment, the driven gear 70 urged by the elastic member 92 moves slightly to the back side of the guide groove 91 after the drive gear 80 is stopped. By the movement of the driven gear 70 to the back side, the tooth pressure (contact pressure) of the teeth of the drive gear 80 and the driven gear 70 is reduced, and the load on the driven gear 70 is reduced. Thereby, the frictional force between the gears can be reduced, and the main arm 8, that is, the transfer cover 8, can be easily opened. If the amount of movement of the driven gear 70 to the back side is large, the teeth of the driven gear 70 come into contact with the teeth on the opposite side of the drive gear 80 as shown in FIG. 5B, so that the main arm 8, that is, the transfer cover 8 can be opened more easily.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, as shown in FIG. 6, the drive gear 80 may be composed of a two-stage coupling gear 81 composed of a large-diameter gear 81b and a small-diameter gear 81c that rotate about a shaft 81a.

  The coupling gear 81 is driven with a small-diameter gear 81c meshed with the driven gear 70 and a large-diameter gear 81b meshed with another gear (not shown). The small diameter gear 81c can be rotated forward and backward by a predetermined amount with respect to the large diameter gear 81b.

  Moreover, you may cover the axis | shaft 70a of the driven gear 70 with the cylindrical separate member 94 like FIG. The separate member 94 is preferably made of a wear-resistant material, and rotates when it hits the inner circular arc portion 91a or the outer circular arc portion 91b of the guide groove 91, thereby facilitating the movement of the shaft 70a and improving the durability.

In the above-described embodiment, the elastic member 92 is used as the urging unit. However, the urging unit is not limited to the elastic member 92 and any member can be used. For example, a coil spring 92a may be used as the urging means as shown in FIG. 8, or a torsion spring 92b may be used as shown in FIG.
In the above-described embodiment, the driven gear 70 is configured to be movable by the swing arm so as to be in contact with and away from the drive gear 80. On the contrary, the driven gear 70 is fixedly arranged and the drive gear 80 is configured to be movable. It is also possible.

  The drive transmission mechanism of the present invention is not only a drive transmission mechanism that transmits driving force to various rotating members in the transfer cover 8 of the image forming apparatus, but also other rotating members in the image forming apparatus such as an intermediate transfer belt, a photosensitive member. The present invention can also be applied to a drive transmission mechanism that transmits a driving force to a body drum, a process unit, or the like.

  Further, when the drive gear stops driving when the image forming apparatus is jammed or abnormally operates, the drive gear may be automatically driven by a predetermined amount of rotation in the direction in which the driven gear exits the guide groove. . As a result, the image forming apparatus stops due to a paper jam or abnormal operation, and the transfer cover 8 can be easily opened when attempting to open the transfer cover for inspection.

  As described above, when the drive gear automatically rotates reversely after stopping driving, if the coupling gear 8 of FIG. 6 is used for the drive gear, the driven gear 70 is moved to the back side of the guide groove 91 as shown in FIG. Even if the tooth surface abuts in the pushing direction, the small-diameter gear 81c of the coupling gear 81 can be rotated in the reverse direction as shown in FIG. 5B.

  5B, the tooth surface of the small diameter gear 81c of the coupling gear 81 can be brought into contact with the tooth surface of the driven gear 70 in the direction in which the shaft 70a of the driven gear 70 exits the guide groove 91. The shaft 70a of the driven gear 70 can be smoothly detached from the guide groove 91. For this reason, the main arm 8, that is, the transfer cover 8, can be easily opened.

1K, 1Y, 1M, 1C: Process units 2K, 2Y, 2M, 2C: Image carrier (photosensitive drum)
8: Transfer cover (main arm)
9: Duplex unit 9a: Transport housing 9b: Return path 12: Transfer cover rotating shaft 15: Transfer device 16: Intermediate transfer belt 17: Driven roller 18: Secondary transfer drive rollers 19K, 19Y, 19M, 19C: Primary transfer roller 20: Secondary transfer roller 20a: Rotating shaft 25: Compression spring 27a: Support shaft (regulator)
28: support plate 30: paper feed tray 30a: paper feed roller 31: paper feed path 32: timing roller pair 32a: timing drive roller 32b: timing driven roller 33: post-transfer conveyance path 34: fixing device 34a: fixing roller 34b: Pressure roller 36: paper discharge path 37: paper discharge roller pair 41: reverse conveyance path 60: sub arm 70: driven gear 80: drive gear 90: inter-shaft regulating member 91: guide groove 92: elastic member 92a: coil spring 92b: Torsion spring

JP 11-119583 A Japanese Patent Laid-Open No. 5-34781 Japanese Patent No. 2722316 JP 2006-117426 A Japanese Patent No. 4387110

Claims (10)

  In a drive transmission mechanism that transmits / cuts driving force from the drive gear to the driven gear by moving the drive gear and the driven gear away from each other, the gear meshes between both shafts of the drive gear and the driven gear. An inter-axis restricting member for restricting the inter-axis distance between the two shafts at the time is disposed, and the shaft of one gear that is movable to contact and separate the two gears to the inter-axis restricting member is A drive transmission mechanism, characterized in that a guide groove is formed for entering and exiting when moving and moving away from and away from the guide groove, and an urging means for urging the movable gear toward the inner side of the guide groove is provided.   2. The drive transmission mechanism according to claim 1, wherein the drive gear is composed of a coupling gear having a large diameter gear and a small diameter gear.   The drive transmission mechanism according to claim 1 or 2, wherein a shaft of a moving gear that enters and exits the guide groove is covered with another member that rotatably contacts the guide groove.   The drive transmission mechanism according to any one of claims 1 to 3, wherein a shaft of the moving gear is supported at a tip of the sub arm of a swing arm composed of a main arm and a sub arm. .   5. The drive transmission mechanism according to claim 4, wherein the urging means is constituted by an elastic member, a coil spring or a torsion spring disposed between the main arm and the sub arm.   An image forming apparatus using the drive transmission mechanism according to any one of claims 1 to 5 as a drive transmission mechanism that transmits a driving force from a main body side of the image forming apparatus to a rotating member in an openable / closable transfer cover. .   An image forming apparatus using the drive transmission mechanism according to any one of claims 1 to 5 as a drive transmission mechanism for transmitting a driving force to an intermediate transfer belt.   An image forming apparatus using the drive transmission mechanism according to any one of claims 1 to 5 as a drive transmission mechanism for transmitting a driving force to a photosensitive drum.   An image forming apparatus using the drive transmission mechanism according to claim 1 as a drive transmission mechanism for transmitting a driving force to a process unit.   10. The drive gear according to claim 6, wherein when the image forming apparatus is jammed or abnormally operated, the drive gear is driven and controlled in a direction in which the shaft of the moving gear comes out of the guide groove after the drive is stopped. 1. An image forming apparatus according to 1.