JP6188524B2 - Drive transmission device, sheet feeding device, and image forming apparatus - Google Patents

Description

  The present invention relates to a drive transmission device, a sheet feeding device, and an image forming apparatus.

2. Description of the Related Art Some conventional image forming apparatuses such as printers, facsimiles, and copiers are configured to feed a sheet stored in a sheet storage unit to the image forming unit by a sheet feeding device.
FIG. 9 shows a drive transmission unit of a conventional sheet feeding apparatus.
The drive gear 41 is supported by a shaft 42 and is always rotated counterclockwise by a motor and gear 40 (not shown). The drive shaft 44 is for transmitting drive force to a feed roller (not shown). The drive shaft 44 is provided with a first partial gear 43 and a second partial gear 47. The second partial gear 47 is engaged with the drive shaft 44 so as to rotate synchronously. The first toothless gear 43 is supported by a support shaft provided in the second toothless gear 47 and is rotated clockwise by a biasing spring 46 provided between the first toothless gear 47 and the second toothless gear 47. It is energized. The first toothless gear 43 and the second toothless gear 47 each have a transmission joint portion (not shown) so that when the gears rotate, the transmission joint portions abut against each other and rotate synchronously. It is configured. Moreover, the cam part 43b and the stopper part 43c are provided in the side surface of the tooth surface 43a in the 1st partial gear 43.
45 is a flapper type solenoid. In the stationary state of the first partial gear 43 (drive shaft 44), the energization of the coil portion 45a of the solenoid 45 is cut off. The coil portion 45a is de-energized, the flapper portion 45b is urged by the urging spring 45c in a direction approaching the first toothless gear 43, and the stopper portion 43c of the first toothless gear 43 is provided at the tip of the flapper portion 45b. Is engaged, the stationary state of the first partial gear 43 is maintained. When a voltage is input to the coil part 45a of the solenoid 45, the flapper part 45b is attracted to the coil part 45a by the electromagnetic force generated by the coil part 45a, and the tip of the flapper part 45b and the stopper of the first intermittent gear 43 The engagement with the portion 43c is released. The disengaged first partial gear 43 starts rotating clockwise by the biasing spring 46 and meshes with the drive gear 41. The rotational force received by the drive gear 41 is transmitted to the second segmented gear 47 by the transmission joint portion, whereby the second segmented gear 47 also starts to rotate, via the drive gear 41 and the meshing drive shaft 44. Rotate the feed roller. The energization of the coil 45a of the solenoid 45 is cut off as soon as the second toothless gear 47 rotates. As a result, the flapper 45b moves in a direction approaching the first toothless gear 43 by the urging force of the urging spring 45c, the tip of the flapper 45b and the cam shape 43b come into contact with each other, and the cam shape is formed with the rotation. It moves along, and it engages with the stopper part 43c again. In this way, the first partial gear 43 returns to a stationary state.

Here, in the configuration as described above, when the energization of the coil portion 45a of the solenoid is cut off, the flapper portion 45b moves toward the stationary position, and an harsh sound that sounds “click” when it collides with the cam shape 43b. However, there is concern that it will occur every time it is in operation.
As a method for reducing the collision noise of the flapper portion 45b, Patent Document 1 proposes a method of attaching a cushioning material such as rubber to the cam surface. However, although this method can reduce the collision sound, it has been desired to reduce the collision sound. Moreover, there is a concern that the cost may be increased by attaching the buffer member.
In Patent Document 2, as a configuration that eliminates collision noise and prevents cost increase, a surface having a larger radius of rotation than the stopper portion 43c is provided on the cam shape 43b to prevent rotation of the toothless gear with respect to the tip of the flapper portion 45b. A configuration in which there is no contact has been proposed.

JP 07-269595 A Japanese Patent No. 3912880

  However, in the configuration as described above, it is necessary to bring the tip of the flapper portion 45b and the cam surface into contact with each other so as not to prevent the rotation of the toothless gear, which is greatly affected by the component accuracy of each component and the assembly accuracy. There is a concern that In order to mitigate such effects, strict management of each part size and high-precision assembly work using jigs are required, resulting in an increase in part management processes, an increase in assembly time, and recovery. Indirect work such as tool management process will increase.

  The present invention has been made in view of the circumstances as described above, and in a drive transmission device provided with a cam member whose rotation is stopped by the movement of the moving member, noise generated when the moving member is moved is inexpensive and simple. It aims at suppressing with a simple structure.

In order to achieve the above object, the present invention provides:
A cam member rotatably provided by a driving force from a driving source and having a locking portion for stopping rotation;
An engagement portion that engages with the engagement portion, an engagement position where the engagement portion engages with the engagement portion, and the engagement between the engagement portion and the engagement portion are released. A movable member movable between the release position;
Have
In the drive transmission device in which the engagement is engaged with the locking portion and the rotation of the cam member is stopped, so that the drive transmission is interrupted.
The cam member is provided with an elastically deformable elastically deformable portion having a larger diameter than the locking portion and having a large-diameter portion capable of coming into contact with the engaging portion of the moving member located at the release position. ,
The elastic deformation portion is elastic in a direction in which the radius of the large-diameter portion decreases as the engagement portion of the moving member positioned at the release position contacts the large-diameter portion by rotation of the cam member. It ’s something that transforms,
When the movement of the moving member from the release position to the engagement position is started in a state where the engagement portion is in contact with the large-diameter portion, the engagement portion is moved along with the rotation of the cam member. It continues to slide on the outer peripheral surface of the cam member from the large diameter portion and is guided to the locking portion.

  According to the present invention, in a drive transmission device provided with a cam member whose rotation is stopped by movement of a moving member, it is possible to suppress noise generated when the moving member moves with an inexpensive and simple configuration.

Side view showing a schematic configuration of the drive transmission device of the present embodiment The perspective view which shows schematic structure of the drive transmission apparatus of a present Example. Schematic for explaining in detail the shape of the cam of the present embodiment Side view showing a schematic configuration of the drive transmission device of the present embodiment Side view showing a schematic configuration of the drive transmission device of the present embodiment Side view showing a schematic configuration of the drive transmission device of the present embodiment Side view showing a schematic configuration of the drive transmission device of the present embodiment Sectional drawing which shows schematic structure of the image forming apparatus of a present Example. The figure which shows the conventional drive transmission part

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

[Example]
Examples will be described below.
FIG. 1 is a side view showing a schematic configuration of the drive transmission device 1 of the present embodiment. FIG. 2 is a perspective view showing a schematic configuration of the drive transmission device 1 of the present embodiment. 3A and 3B are schematic views for explaining in detail the shape of the cam of the present embodiment, in which FIG. 3A is a side view and FIG. 3B is a perspective view. 4-7 is a side view which shows schematic structure of the drive transmission apparatus 1 of a present Example, and is a figure for demonstrating operation | movement progress. FIG. 8 is a cross-sectional view illustrating a schematic configuration of the image forming apparatus 3 including the sheet feeding device 2 to which the drive transmission device 1 is applied in the present embodiment.

First, an image forming operation of the image forming apparatus of this embodiment will be described.
In the sheet feeding apparatus 2 shown in FIG. 8, the recording material S stacked on the sheet stacking unit 20 is separated into a single sheet by a half-moon shaped feeding roller 21 and a separating unit (not shown), and is sent to the conveying roller pair 22. . At this time, an electrostatic latent image is formed on the photosensitive member 24 a in the image forming unit (image forming unit) 24 by the laser light emitted from the optical unit 23, and is developed by a developing unit (not shown) provided in the image forming unit 24. A toner image is developed on the surface of the photoreceptor 24a. The recording material S sandwiched and transported by the transport roller pair 22 is directly sandwiched between the photosensitive member 24 a and the transfer roller 25, and the toner image on the photosensitive member 24 a is transferred onto the recording material S by the transfer roller 25. Thereafter, the recording material S is heated and pressed by a fixing unit including a heating device 26 and a pressure roller 27, whereby the toner image is fixed on the recording material S. The fixed recording material S is nipped and conveyed by the conveyance roller pair 28 and the discharge roller pair 29 and is discharged out of the apparatus.

Next, the configuration of the drive transmission device (drive transmission unit) 1 of this embodiment will be described with reference to FIGS.
A drive gear (drive transmission gear) 11 is supported by a shaft 12 and is always rotated counterclockwise in FIG. 1 by a drive force (rotational force) from a motor (drive source) via a gear train.
The drive shaft 14 transmits driving force to the feeding roller 21. A first segmental gear 13 and a second segmental gear 17 are detachably attached to the drive shaft 14. The second partial gear 17 is engaged with the drive shaft 14 so as to rotate synchronously. Here, the first partial gear 13 corresponds to a toothless gear that includes a toothed portion that meshes with the drive gear 11 and a toothless portion that does not mesh with the drive gear 11.

The first partial gear 13 is supported by a support shaft 17a provided in the second partial gear 17 and is biased by a biasing spring 16 provided in a space with the second partial gear 17 in FIG. It is urged clockwise. The first segmented gear 13 and the second segmented gear 17 are each provided with a transmission joint portion (not shown). When the gears rotate, the transmission coupling portions abut against each other so as to rotate synchronously. It is configured.
Further, the first segmented gear 13 is integrally provided with a cam-shaped portion 13b having a stopper portion 13c on the side surface of the tooth surface 13a. Here, the stopper portion 13c corresponds to a locking portion for stopping rotation, and the cam-shaped portion 13b corresponds to a cam member.

15 is a flapper type solenoid (release means). The solenoid 15 is provided with a coil portion 15a, a flapper portion 15b as a moving member, and an urging spring 15c.
In the stationary state (stop state) of the first toothless gear 13 (drive shaft 14), the energization of the coil portion 15a of the solenoid 15 is cut off. The coil portion 15a is de-energized, the flapper portion 15b is urged by the urging spring 15c in a direction approaching the first toothless gear 13, and the engagement portion 15b1 at the tip of the flapper portion 15b is biased to the first toothless gear. The stationary state of the first intermittent gear 13 is maintained by the engagement of the 13 stopper portions 13c. When the coil portion 15a is energized, the electromagnetic force generated by the coil portion 15a causes the flapper portion 15b to move against the biasing force of the biasing spring 15c, and the engagement portion 15b1 of the flapper portion 15b and the first portion The engagement of the partial gear 13 with the stopper portion 13c is released.

  That is, the flap portion 15b has an engagement position where the engagement portion 15b1 engages with the stopper portion 13c (the first toothless gear 13 becomes stationary), and engagement between the engagement portion 15b1 and the stopper portion 13c. It is configured to be movable between a release position where is released. Then, the engaging portion 15b1 is engaged with the stopper portion 13c, the rotation of the cam-shaped portion 13b is stopped, and the first partial gear 13 is stationary in a state where the first partial gear 13 is not meshed with the drive gear 11. By being in the state, drive transmission in the drive transmission unit is interrupted.

  As described above, the drive transmission portion is configured such that the first intermittent gear 13 is intermittently driven by the drive gear 11 by repeatedly engaging and releasing the engagement portion 15b1 and the stopper portion 13c. Has been.

Next, the cam shape portion 13b of the first partial gear 13 will be described in detail with reference to FIG.
As shown in FIG. 3, the cam-shaped portion 13b is provided with a stopper portion 13c, a contact portion (contact surface) 13d, a notch portion 13e, and a notch portion 13h.
Here, the stopper portion 13c is for engaging with the flapper portion 15b as described above. The contact portion 13d is provided with a cam locking surface 13d1 and a return surface 13d2. When the engaging portion 15b1 of the flapper portion 15b comes into contact with the contact portion 13d, the cam rotates and continues to slide on the contact portion 13d and is guided to the stopper portion 13c. The cam locking surface 13d1 is a surface (cam surface (outer peripheral surface)) set to have a radius RD downstream of the stopper portion 13c in the cam rotation direction, and is associated with the flapper portion 15b locked by the stopper portion 13c. This is the surface with which the joint portion 15b1 abuts. Note that the cam rotation direction is the rotation direction of the cam-shaped portion 13 b and is the same as the rotation direction of the first toothless gear 13 and the drive shaft 14. Further, the rotation center (rotation axis, axis) O of the cam-shaped portion 13 b is the same as the rotation center of the first toothless gear 13 and the drive shaft 14.

The contact portion 13d is provided with an elastically deformable portion 13f that can be elastically deformed as a feature of the present embodiment.
Here, a notch portion 13e is provided so as to be adjacent to the downstream side of the elastic deformation portion 13f in the cam rotation direction. Further, a notch portion 13h is provided adjacent to the elastic deformation portion 13f in the rotation axis direction so as to follow the cam rotation direction. The notch portion 13e has a form (form having a groove) in which a part of a substantially annular cam member is notched in the cam rotation direction and the vertical direction (radial direction).

  By providing such notches 13e and 13h, an elastic deformation portion 13f is configured. Here, it can be said that the elastically deforming portion 13f is a plate-like portion provided in a curved shape along the circumferential direction (rotating direction) of the cam-shaped portion 13b. At this time, the end (one end) on the downstream side in the cam rotation direction is a free end, and the end (the other end) on the upstream side in the cam rotation direction is connected to the cam member main body.

And the return surface 13d2 is formed in the surface (outer peripheral surface) of the elastic deformation part 13f. In the natural state, the return surface 13d2 is such that the radial distance (radius) from the rotation center O of the cam-shaped portion 13b is larger than the distance RE to the engaging portion 15b1 of the flapper portion 15b located at the release position. Is formed. Here, the return surface 13d2 has a radius larger than that of the stopper portion 13c, and corresponds to a large-diameter portion that can come into contact with the engaging portion 15b1 of the flapper portion 15b located at the release position.
In the elastically deforming portion 13f, as the cam-shaped portion 13b rotates, the return surface 13d2 comes into contact with and is pressed against the engaging portion 15b1 of the flapper portion 15b located at the release position, thereby reducing the radius of the return surface 13d2. It is comprised so that it may elastically deform in the direction.

  Further, in the elastically deforming portion 13f, a free end portion 13g which is an end portion on the downstream side in the cam rotation direction is formed with an inclined surface whose radius gradually decreases toward the downstream when viewed from the rotation axis direction. ing. Here, a portion of the surface (outer peripheral surface) of the free end portion 13g that is naturally larger than the distance RE corresponds to a large-diameter portion.

Further, the edge 13g1 on the downstream side in the cam rotation direction of the free end portion 13g of the elastic deformation portion 13f is formed to have a radius RG that does not contact the engaging portion 15b1 of the flapper portion 15b located at the release position. . That is, the radius of the edge 13g1 is smaller than the distance RE from the rotation center O of the cam-shaped portion 13b to the engaging portion 15b1 located at the release position. Here, the end edge 13g1 corresponds to a small diameter portion.
As a result, when the rotation of the cam-shaped portion 13b starts (restarts) with the flapper portion 15b positioned at the release position, the free end portion 13g in the contact portion 13d (elastically deforming portion 13f) It will contact | abut first to the engaging part 15b1 located in a cancellation | release position.

Next, the operation of the drive transmission device 1 according to the present embodiment will be described with reference to FIGS.
When a voltage is input to the coil portion 15a of the solenoid 15, the flapper portion 15b is attracted to the coil portion by the electromagnetic force generated by the coil portion 15a, and the engaging portion 15b1 of the flapper portion 15b and the first intermittent gear 13 are obtained. The engagement with the stopper portion 13c is released.
As shown in FIG. 4, the first intermittent gear 13 that has been disengaged from the flapper portion 15 b starts rotating clockwise by the biasing spring 16 and meshes with the drive gear 11. The rotational force received by the drive gear 11 is transmitted to the second segmented gear 17 by a transmission joint portion (not shown), and the second segmented gear 17 also starts to rotate and meshes with the drive gear 11 to drive the drive shaft 14. Rotate.

When the rotation of the first toothless gear 13 proceeds, as shown in FIG. 5, the engaging portion of the flapper portion 15b passes through the notch portion 13e of the cam-shaped portion 13b and the edge 13g1 of the elastic deformation portion 13f. 15b1 contacts the free end portion 13g of the elastic deformation portion 13f.
When the rotation of the first toothless gear 13 further proceeds, the elastically deforming portion 13f is pushed by the engaging portion 15b1 of the flapper portion 15b to decrease the radius as shown in FIG. 6 (A shown in FIG. 6). Direction).

  At this time (with the engagement portion 15b1 in contact with the elastic deformation portion 13f), the energization of the coil portion 15a of the solenoid 15 is cut off. Thereby, in the flapper part 15b, the movement to the direction (B direction shown in FIG. 7) which returns to an engagement position (the stationary state of the 1st partial gear 13) by the urging | biasing force of the urging | biasing spring 15c is started. . As shown in FIG. 7, the elastic deformation portion 13f pushed by the engagement portion 15b1 of the flapper portion 15b is further elastically deformed (rotates while elastically deforming) as the cam-shaped portion 13b rotates.

Thereafter, the engaging portion 15b1 of the flapper portion 15b continues to slide on the contact portion 13d (on the outer peripheral surface) following the cam shape of the rotating cam shape portion 13b, and passes through the cam locking surface 13d1 to stop the stopper. It is guided to the portion 13c and engages with the stopper portion 13c again.
In this way, the first partial gear 13 returns to the stationary state shown in FIG.

  Thus, in this embodiment, when the energization of the coil portion 15a of the solenoid 15 is cut off and the flapper portion 15b tries to return to the engagement position shown in FIG. 1 again, the engagement portion 15b1 of the flapper portion 15b It exists in the state which contacted the elastic deformation part 13f of the shape part 13b. Then, the engaging portion 15b1 of the flapper portion 15b gradually approaches the engaging position while elastically deforming the elastic deformation portion 13f.

  Therefore, the occurrence of noise (a harsh sound), which is a concern when the flapper portion 15b returns to the engagement position, may cause an increase in the part management process, an increase in assembly time, a jig management process, etc. It can be suppressed with an inexpensive and simple configuration without increasing the indirect work.

  Here, in the present embodiment, the free end portion 13g of the elastically deforming portion 13f is formed to be an inclined surface, but this is not restrictive. In other words, the engaging portion 15b1 located at the release position may be provided with an inclined surface such that the radial distance from the rotation center O of the cam-shaped portion 13b increases toward the upstream in the cam rotation direction. Good. Further, the end edge 13g1 is formed to have a radius RG that does not come into contact with the engaging portion 15b1 of the flapper portion 15b located at the release position. However, the present invention is not limited to this, and the end edge 13g1 is formed at the release position. It may be capable of coming into contact with the engaging portion 15b1 located at the position. When the engaging portion 15b1 positioned at the release position comes into contact with the elastic deformation portion 13f along with the rotation of the cam shape portion 13b, the rotation operation of the cam shape portion 13b is not restricted, and the rotation operation of the cam shape portion 13b is not restricted. As long as the elastic deformation operation of the elastic deformation portion 13f is smoothly performed.

In the present embodiment, the cam-shaped portion 13b is formed integrally with the first partial gear 13, but the present invention is not limited to this. The cam-shaped portion 13b is configured to be able to rotate synchronously with the first partial gear 13 so that the first partial gear 13 does not mesh with the drive gear 11 when the rotation of the cam-shaped portion 13b stops. As long as it is a thing, it may be a separate body from the first partial gear 13.
In the present embodiment, the configuration in which the driving force is transmitted to the feeding roller 21 by the drive transmission device 1 has been described. However, the present invention is not limited to this. That is, it is only necessary that the drive transmission to the member driven during image formation is performed by the drive transmission device 1.

  DESCRIPTION OF SYMBOLS 1 ... Drive transmission device, 13b ... Cam shape part, 13c ... Stopper part, 13d2 ... Return surface, 13f ... Elastic deformation part, 15b ... Flapper part, 15b1 ... Engagement part

Claims (8)

A cam member rotatably provided by a driving force from a driving source and having a locking portion for stopping rotation;
An engagement portion that engages with the engagement portion, an engagement position where the engagement portion engages with the engagement portion, and the engagement between the engagement portion and the engagement portion are released. A movable member movable between the release position;
Have
In the drive transmission device in which the engagement is engaged with the locking portion and the rotation of the cam member is stopped, so that the drive transmission is interrupted.
The cam member is provided with an elastically deformable elastically deformable portion having a larger diameter than the locking portion and having a large-diameter portion capable of coming into contact with the engaging portion of the moving member located at the release position. ,
The elastic deformation portion is elastic in a direction in which the radius of the large-diameter portion decreases as the engagement portion of the moving member positioned at the release position contacts the large-diameter portion by rotation of the cam member. It ’s something that transforms,
When the movement of the moving member from the release position to the engagement position is started in a state where the engagement portion is in contact with the large-diameter portion, the engagement portion is moved along with the rotation of the cam member. A drive transmission device characterized in that it continues to slide on the outer peripheral surface of the cam member from the large diameter portion and is guided to the locking portion.   2. The drive according to claim 1, wherein an inclined surface whose radius gradually decreases toward the downstream is provided at an end of the large-diameter portion on the downstream side in the rotation direction of the cam member. Transmission device. On the downstream side of the rotation direction of the cam member from the large diameter portion of the elastic deformation portion,
2. A small-diameter portion having a radius smaller than the radial distance from the rotation center of the cam member to the engaging portion of the moving member located at the release position is provided. Or the drive transmission device of 2.   The elastically deforming portion is a plate-like portion provided in a curved shape on the cam member so as to be along the circumferential direction, and an upstream end in the rotational direction is defined with a downstream end portion in the rotational direction of the cam member as a free end. The drive transmission device according to any one of claims 1 to 3, wherein an end portion on the side is connected to the cam member main body. A drive transmission gear for transmitting a driving force from the drive source;
A toothed portion meshing with the drive transmission gear, and a chipped gear including a chipped portion not meshing with the drive transmission gear;
Have
The cam member rotates synchronously with the chipped gear so that the chipped gear does not mesh with the drive transmission gear when rotation of the cam member stops. The drive transmission apparatus of any one of Claims.   The drive transmission device according to claim 5, wherein the cam member is formed integrally with the chipped gear. The drive transmission device according to any one of claims 1 to 6,
A feeding roller driven by the drive transmission device to feed the sheet;
A sheet feeding apparatus comprising: It has a drive transmission device given in any 1 paragraph of Claims 1 thru / or 6,
An image forming apparatus, wherein drive transmission to a member driven at the time of image formation is performed by the drive transmission device.

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