JP5780800B2 - Clutch mechanism, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention has a cam, a partly missing tooth part, a toothless gear that can rotate by meshing with a drive gear at the toothed part, and a locking member that stops the rotation of the toothless gear. The present invention relates to a clutch mechanism that switches a transmission direction of power to a toothless gear by bringing a locking member into and out of contact with a cam. The present invention also relates to an image reading apparatus and an image forming apparatus including the same.

  2. Description of the Related Art Conventionally, an invention described in Patent Document 1 is disclosed as an invention relating to a clutch mechanism that switches between rotation and stop of a feeding roller inside a feeding device, which is an image forming apparatus that includes a feeding device that feeds sheets. ing. The invention described in Patent Document 1 relates to a clutch mechanism including a toothless gear that can rotate integrally with a gear portion and a cam, and a lever that can be engaged with the cam. The cam has a cam release surface and a cam return surface, and the cam return surface is configured to have a surface higher than the cam release surface. With such a configuration, the distance between the tip of the lever and the cam is set to be small, so that during the return operation in which the lever moves to the cam side, the lever contacts the cam return surface with a long diameter, so that the noise of “click” is generated. It is suppressed.

  A configuration of a clutch mechanism included in a conventional sheet feeding apparatus will be described with reference to FIG. 8 as a configuration in which such a “click” noise of the lever and the cam is generated. FIG. 8A is a side view showing a configuration of a conventional clutch mechanism 152, and shows a state where the lever 61a is engaged with the cam 62a. FIG. 8B is a partially enlarged side view of FIG. FIG. 8C is a side view showing the configuration of the conventional clutch mechanism 152 and shows a state in which the lever 61a is separated from the cam 62a. FIG. 8D is a partially enlarged side view of FIG.

  As shown in FIGS. 8A and 8B, the clutch mechanism 152 has a toothless gear 62 attached to the feed roller shaft 63, a lever 61a operated by a solenoid 61, a drive gear 22, and the like. Yes. The lever 61a is engaged with the engaging portion 62b of the missing tooth gear 62, and the rotation of the missing tooth gear 62 is stopped.

  As shown in FIGS. 8C and 8D, when a voltage is applied to the solenoid 61 and excited by the feeding operation signal, the lever 61a is attracted to the solenoid 61 by the generated magnetic flux, and the lever 61a Retracting from the engaging part 62b of the gear 62, the toothless gear 62 starts to rotate.

  8 (c) and 8 (d), Patent Document 1 describes a phenomenon in which a contact noise is generated when the lever 61a contacts the solenoid 61 when the lever 61a is retracted. Also in this invention, the idea of providing an elastic member such as sponge or soft rubber at the contact portion was disclosed.

  Here, in order to constitute a clutch mechanism between the lever 61a and the toothless gear 62, the solenoid 61, the main body frame 21 to which the solenoid 61 is attached, the feeding frame 64 that covers the feeding roller, the bearing of the feeding roller, A plurality of parts such as the feeding roller shaft 63 are required. Depending on the dimensional accuracy and mounting accuracy of these multiple parts, when the lever 61a is attracted by the solenoid 61 and moved to the elastic member 61c, the cam 62a and the claw 61b come into contact with each other, preventing rotation of the toothless gear 62, There is a possibility that the feeding roller 6 does not rotate, leading to poor feeding.

  In order to prevent such a feeding failure due to the contact between the cam 62a and the claw 61b, when the lever 61a is sucked and comes into contact with the elastic member 61c, an error in the dimensional accuracy and assembly accuracy of the plurality of parts described above. Even in a stacked state, it was necessary to do the following. That is, in order to securely retract the claw 61b from the engaging portion 62b, it is necessary to increase the distance L1 between the tip of the claw 61b and the engaging portion 62b when the lever 61a is sucked.

JP 11-190410 A

  However, if the distance L1 is increased, the movable stroke when the lever 61a (locking member) retracts increases, so that the rotation speed of the lever 61a (locking member) when contacting the elastic member 61c increases. The contact sound becomes louder.

  Further, the addition of the elastic member 61c for reducing the contact sound of the lever 61a (locking member) causes an increase in cost.

  In view of the above circumstances, an object of the present invention is to provide a clutch mechanism that can reduce the contact noise of a lever without increasing the cost.

In order to achieve the above object, a clutch mechanism of the present invention has a cam, a partly toothed part, a toothless part that meshes with a drive gear and is rotatable, and the toothless gear. Rotation means for applying a rotational force to the toothless gear to engage with the drive gear, and a locking member that engages with an engagement portion provided on the cam to stop the rotation of the toothless gear ; A retracting means for retracting the locking member from an engaging position engaging with the engaging portion to a retracted position retracted from the engaging portion; and returning the locking member from the retracted position to the engaging position. comprising a return means, and a restriction to limit the operating range of the locking member the locking member to the segment gear when retracting by said retreating means, said toothless gear with the locking member A passing section is provided for passing the restricting section that rotates with rotation. Characterized in that was.

  According to the present invention, the contact noise of the locking member is reduced without increasing the cost.

It is sectional drawing which shows the structure of an image forming apparatus provided with the clutch mechanism which concerns on Example 1 of this invention. FIG. 10 is a plan view of the clutch mechanism as viewed from a direction orthogonal to the feeding roller shaft, excluding the frame. FIG. 10 is a plan view of the clutch mechanism as viewed from a direction orthogonal to the feeding roller shaft, excluding the frame. It is a side view etc. which show the operation process of a clutch mechanism. It is an enlarged side view etc. which show the structure of a missing tooth gear, a lever, and a solenoid. FIG. 6 is a side view illustrating the configuration of a clutch mechanism according to a second embodiment. It is sectional drawing which shows the structure of the image reading apparatus with which the clutch mechanism based on Example 3 is applied. It is a side view etc. which show the structure of the conventional clutch mechanism.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, there is no specific description. As long as the scope of the invention is not limited to these, it is not intended.

  FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus 100 including a clutch mechanism 52 according to Embodiment 1 of the present invention. The image forming apparatus 100 is an image forming apparatus using an electrophotographic image forming process. As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 100A. Inside the apparatus main body 100A, an image forming unit 2 that forms an image is provided. Provided. The image forming unit 2 includes a photosensitive drum 10 that is an “image carrier”, a transfer roller 11 that is a “transfer device”, and the like. Details will be described below.

  First, a schematic configuration will be described along the flow of the recording material S. The image forming apparatus 100 forms an image by an electrophotographic method. The image forming apparatus 100 transports the recording material S to the image forming unit 2 by the feeding / conveying device 1 (feeding / conveying means) to transfer the toner image, and conveys the recording material S to the fixing device 3 (fixing means). Then, after the toner is fixed, the toner is discharged to the discharge unit 4. Specifically, a cassette 5 for loading and storing the recording material S is loaded in the lower part of the image forming apparatus 100. The recording materials S stacked and accommodated in the cassette 5 constituting the feeding / conveying device 1 are sequentially sent out from the uppermost recording material S by the feeding roller 6 rotating in the counterclockwise direction. 8 is sent to the image forming unit 2.

  Laser light corresponding to image information is irradiated onto the photosensitive drum 10 rotating in the clockwise direction by the laser scanner 9, and an electrostatic latent image is formed on the photosensitive drum 10. The electrostatic latent image is developed with toner at a developing unit in the process cartridge 30. The toner image formed on the photosensitive drum 10 is transferred to the recording material S as an unfixed image by the transfer roller 11. The recording material S carrying the unfixed image is sent to the fixing device 3 and subjected to fixing processing by the fixing unit T in the fixing device 3. The recording material S that has passed through the fixing device 3 and has undergone the fixing process is transported by the transport roller pair 12 and the discharge transport roller pair 13 and is discharged to the discharge unit 4 at the top of the device.

  In addition, in the apparatus main body 100 </ b> A, an electrical unit 14 having a power supply unit of the image forming apparatus 100 and a control board for controlling the image forming apparatus 100 is provided.

  The front and back side recording of the recording material S will be described. When recording is performed on both sides of the recording material S, the recording material S that has passed through the fixing device 3 and has been image-recorded on the front side is switched back and conveyed by the reverse rotation driving of the discharge conveyance roller pair 13. Further, the recording material S is conveyed again to the image forming unit 2 by the conveying roller pairs 15 and 16. Then, as described above, the image is recorded on the back side of the recording material S and then discharged.

  When feeding from the manual feed unit 17, the manual feed tray 18 is opened and the recording material S is stacked on the manual feed tray 18. The recording material S loaded on the manual feed tray 18 is sequentially fed from the uppermost recording material S by a manual feeding roller 19 that rotates in the clockwise direction, and an image forming unit that is an “image forming unit” by the conveying roller pair 8. Sent to 2. After being sent to the image forming unit 2, it is omitted because it is the same as described above. Next, the configuration of the missing gear 82 in the clutch mechanism 52 that switches the driving of the feeding roller 6 and the lever 81a provided in the solenoid 81 in the present embodiment will be described in more detail with reference to FIGS. .

  FIG. 2 shows a state before the feeding operation is performed. FIG. 2A is a plan view of the clutch mechanism 52 viewed from a direction orthogonal to the feed roller shaft 83 except for the frame. FIG. 2B is a side view of the clutch mechanism 52 as viewed from below in FIG. FIG. 2C is a partially enlarged side view of FIG. 2B showing the configuration around the lever 81a.

  As shown in FIGS. 2A and 2B, the drive gear 22 is provided on the main body frame 41. The drive gear 22 shown in FIG. 2B is rotated counterclockwise in FIG. 2B by a drive motor and a gear train (not shown).

  The feed roller shaft 83 is a shaft that can rotate integrally with the feed roller 6. The feed roller shaft 83 is provided with a toothless gear 82 that can rotate integrally with the feed roller shaft 83. The missing tooth gear 82 has a cam 82c. The toothless gear 82 has a gear portion 82x, and the gear portion 82x has a toothed portion 82a having teeth and a toothless portion 82b having no teeth in a part thereof. The toothless gear 82 is a gear that can rotate by meshing with the drive gear 22 at the toothed portion 82a.

  Such a toothless gear 82 is provided with a tension spring 87 as a “rotation biasing means” at the cam 82c, and the toothless gear 82 is biased clockwise in FIG. 2 (b). The tension spring 87 applies a rotational force to the missing gear 82 in order to mesh the missing gear 82 with the drive gear 22.

  The cam 82c has a peripheral surface whose diameter increases in the circumferential direction, and an engaging portion 82d is formed by a step between a portion having the smallest diameter and a portion having the largest diameter. The engaging portion 82d is a portion where a claw 81b of a lever 81a described later is engaged.

  On the other hand, the solenoid 81 is attached to the main body frame 41. The solenoid 81 is provided with a lever 81a which is a “locking member”. The lever 81a is a member that engages with an engaging portion 82d provided on the cam 82c to stop the rotation of the missing gear 82. The configuration of the lever 81a will be specifically described as follows. That is, the tip of the lever 81a is bent, and the lever 81a has a claw 81b at the tip. The base end of the lever 81a is supported so as to be a fulcrum when the tip of the lever 81a swings in a direction along the surface of the main body frame 41.

  Further, a tension spring 81e as a “return means” is attached to the base end side of the lever 81a. The tension spring 81e is a member that returns the lever 81a in a direction in which the lever 81a is brought into contact with the cam 82c. The tension spring 81e biases the lever 81a so that the lever 81a rotates in the clockwise direction in FIG. Then, the tip of the lever 81a swings in the clockwise direction, so that the claw 81b of the lever 81a engages with the engaging portion 82d of the cam 82c (see FIG. 2C). Thereby, the rotation of the missing gear 82 is stopped.

  Further, the solenoid 81 that is the “retracting means” described above is a member that retracts the lever 81a from the engaging position with the engaging portion 82d to the retracting position. Therefore, as shown in FIGS. 3B and 3C, when the lever 81a is attracted to the solenoid 81, the tip of the lever 81a swings counterclockwise, so that the claw 81b of the lever 81a cams. 82c is disengaged from the engaging portion 82d. Thereby, the missing gear 82 can be rotated.

  The missing gear 82 of the clutch mechanism 52 is provided with an abutting portion 82e that is a “restricting portion” that restricts the operating range of the lever 81a. The contact portion 82e is configured integrally with the missing gear 82. The missing gear 82 is provided with an extending portion 82f (see FIG. 2C) extending in a direction orthogonal to the feeding roller shaft 83 and in a direction away from the feeding roller shaft 83. A contact portion 82e is provided with 82f as a seating surface. The contact portion 82e has a predetermined height in the direction in which the feed roller shaft 83 extends. When the lever 81a swings away from the cam 82c, the lever 81a comes into contact with the contact portion 82e so that the swing is limited.

  FIG. 3 shows a state when the feeding operation is performed. FIG. 3A is a plan view of the clutch mechanism 52 viewed from a direction orthogonal to the feed roller shaft 83 except for the frame. FIG. 3B is a side view of the clutch mechanism 52 as viewed from below in FIG. FIG. 3C is a partially enlarged side view of FIG. 3B showing the configuration around the lever 81a.

  As shown in FIGS. 3B and 3C, when a voltage is applied to the solenoid 81 by the clutch operation signal and excited, the lever 81a is attracted to the solenoid 81 by the generated magnetic flux, and the tip of the lever 81a is counteracted. Swings clockwise. Then, the claw 81b of the lever 81a is retracted from the engaging portion 82d of the cam 82c to be disengaged, and the lever 81a comes into contact with the contact portion 82e and stops. As a result, the toothless gear 82 starts to rotate in the clockwise direction by the biasing force of the tension spring 87. Next, the toothed portion 82a of the toothless gear 82 meshes with the drive gear 22, the rotation of the drive gear 22 is transmitted, and the toothless gear 82 continues to rotate clockwise in FIG.

  Then, the feeding roller shaft 83 that rotates integrally with the toothless gear 82 rotates, and the feeding roller 6 that rotates together with the feeding roller shaft 83 rotates. As a result, the recording material S is fed and image formation is performed by the process described above.

  In addition, after a predetermined time from now, voltage application to the solenoid 81 is stopped, and the lever 81a is rotated clockwise again by the urging force of the tension spring 81e as shown in FIGS. 81b contacts the cam 82c.

  FIG. 4 is a side view showing an operation process of the clutch mechanism 52. FIG. 4A is a side view showing a state where the claw 81b of the lever 81a is engaged with the engaging portion 82d of the cam 82c. As shown in FIG. 4A, when the claw 81b of the lever 81a is engaged with the engaging portion 82d of the cam 82c, the toothless portion 82b of the gear portion 82x faces the drive gear 22. The driving force of the driving gear 22 is not transmitted to the missing gear 82.

  FIG. 4B is a side view showing a state in which the claw 81b of the lever 81a is retracted from the engaging portion 82d of the cam 82c. As shown in FIG. 4B, when the claw 81b of the lever 81a is retracted from the engaging portion 82d of the cam 82c, the tension spring 87 is contracted, and the cam 82c rotates in the clockwise direction. Then, the toothed portion 82a of the gear portion 82x is meshed with the teeth of the drive gear 22. Then, the driving force of the driving gear 22 is transmitted to the toothless gear 82.

  FIG. 4C is a side view showing a state where the missing gear 82 is further rotated from the state of FIG. As shown in FIG. 4 (c), the toothless gear 82 rotates and the state in which the toothed portion 82 a faces the drive gear 22 shifts to the state in which the toothless portion 82 b faces the drive gear 22. To go. The tension spring 87 extends gradually from the state of FIG.

  FIG. 4D is a side view showing a state where the missing gear 82 is further rotated from the state of FIG. As shown in FIG. 4D, the toothless gear 82 makes one rotation, and the claw 81b of the lever 81a engages with the engaging portion 82d of the cam 82c again. That is, this also returns to the state of FIG. As a result, the rotation of the missing gear 82 is stopped, and the feeding operation is completed.

  FIG.4 (e) is the partially expanded perspective view which looked at the figure of FIG.4 (c) from another angle. As shown in FIG. 4E, the lever 81a is provided with a notch 81c. The notch 81c is provided so as not to hinder the rotation of the abutting portion 82e when the toothless gear 82 rotates. When the contact part 82e passes through the notch part 81c, the missing tooth gear 82 is rotatable.

  FIG. 5A is an enlarged side view showing the configuration of the missing gear 82, the lever 81 a, and the solenoid 81. FIG. 5B is an enlarged exploded view showing the configuration of the missing gear 82 and the lever 81a. In order for the claw 81b of the lever 81a to retreat from the engaging portion 82d of the cam 82c as shown in FIG. 5A, the “length LA of the claw 81b” shown in FIG. The relationship with the distance LB from the engaging portion 82d of the gear 82 to the contact portion 82e only needs to be LA <LB. As in this embodiment, by providing the contact portion 82e in the missing gear 82, it is only necessary to consider only the dimensional accuracy of the two components of the missing gear 82 and the lever 81a without using a plurality of components. .

  Conventionally, in order to take into account the dimensional accuracy and mounting accuracy of a plurality of components, what was set as LB-LA = 1 mm is set as LB-LA = 0.3 mm in this embodiment. By setting LB-LA = 0.3 mm, the movable stroke when the lever 81a is attracted by the solenoid 81 can be reduced, and the rotation speed when the lever 81a contacts the contact portion 82e can be reduced. Therefore, it is possible to reduce the contact sound when the lever 81a contacts the contact portion 82e.

Table 1 shows the measurement results of the contact sound of the lever in the form of Example 1 with and without an elastic member. Each measurement was made 10 times, and the measured value is shown in dB. The lever stroke without the elastic member is measured with the same stroke as the movable stroke with the elastic member.

  As shown in Table 1, by adding an elastic member, the average value of 10 times is reduced by 6.31 dB, and in the embodiment of Example 1, the average value of 10 times is 8.3 dB compared to the case of having an elastic member. It has become possible to reduce this.

  As described above, according to the embodiment, the movable stroke of the lever 81a can be reduced, and the rotation speed when the lever 81a abuts against the abutting portion 82e can be slowed. The contact noise can be reduced.

  The sound was measured using LA-5111, a broadband precision sound level meter manufactured by Ono Sokki Co., Ltd., and the position of the condenser microphone was measured at a position 50 cm away from the solenoid 81 in the horizontal direction. Moreover, the temperature / humidity and pressure during measurement are 972 hpa at 20.7 ° C. and 58%.

  FIG. 6A is a side view illustrating the configuration of the clutch mechanism 252 according to the second embodiment. FIG. 6B is a partially enlarged side view of FIG. Of the configuration of the clutch mechanism 252 of the second embodiment, the same configurations and effects as those of the clutch mechanism 52 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate. Since the second embodiment can be applied to the same image forming apparatus as that of the first embodiment, the description of the image forming apparatus is omitted. The clutch mechanism 252 will be described with reference to FIGS. 6A and 6B, and particularly the configuration of the toothless gear 282 and the lever 81a. 6A and 6B show a state in which a voltage is applied to the solenoid 81 by the clutch operation signal and the solenoid 81 is excited, and the lever 81a is attracted to the solenoid 81 by the generated magnetic flux.

  In the second embodiment, a missing tooth gear 282 is used instead of the missing tooth gear 82. Further, the configuration of the first embodiment is different from the configuration of the first embodiment in that a contact portion 282e formed of an elastic member as a “buffer member” that is a “restriction portion” is used instead of the contact portion 82e. The contact portion 282e is formed of an elastic member, and a material such as sponge or soft rubber is used as the material thereof. In this way, the abutting portion 282 e that is a “restricting portion” that restricts the operating range of the lever 81 a when the lever 81 a is attracted by the solenoid 81 is provided in the toothless gear 282.

  In the conventional example described above, when the solenoid 81 is provided with an elastic member, the claw 81b is engaged with the engaging portion when the lever 81a is attracted to the solenoid 81 in consideration of the dimensional accuracy and assembly accuracy of a plurality of components. The following can be said from the necessity to make a configuration for reliably retracting from 82d. That is, as shown in FIG. 8D, it is necessary to increase the distance L1 between the claw 81b of the lever 61a and the engaging portion 82d of the missing gear 82. By increasing the distance L1, the movable stroke when the lever 81a is retracted from the cam 62a is increased, so that the rotation speed of the lever 81a when contacting the elastic member 61c is increased, and the contact noise is increased. There was a problem.

  As in the second embodiment, by providing the contact portion 282e of the elastic member on the missing gear 282, only the three dimensional accuracy of the lever 81a, the missing gear 82, and the elastic member 61c are taken into consideration, as in FIG. LA <LB (LB is a distance from the engaging portion 82d to the contact portion 282e) may be set. Therefore, the movable stroke when the lever 81a is sucked can be reduced, and the rotation speed when the lever 81a contacts the contact portion 282e can be reduced. Therefore, the contact when the lever 81a contacts the contact portion 282e. Sound can be reduced.

  FIG. 7 is a cross-sectional view illustrating a configuration of an image reading device 60 to which the clutch mechanism according to the third embodiment is applied. Of the configuration of the clutch mechanism of the third embodiment, the same configurations and effects as those of the clutch mechanism 52 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate. Since the third embodiment can be applied to the same image forming apparatus as that of the first embodiment, the description of the image forming apparatus is omitted.

  As shown in FIG. 7, the paper P is fed in the direction of the arrow X by the feed roller 67, the image is read by the image reading unit 68 that reads the image, and the paper is discharged in the direction of the arrow Y. Reading ends. Similarly to the above-described configuration, the feed roller 67 is attached with a toothless gear 82 that rotates integrally, and the claw of the lever 81a attached to the solenoid 81 is engaged by the engaging portion 82d. It is. The feeding roller 67 is rotated by the clutch operation signal, feeds the paper P, and reads an image. The feeding roller 67 may be provided with a missing gear 282 instead of the missing gear 82.

  Also in this embodiment, by providing the contact portion of the lever on the toothless gear, the movable stroke of the lever can be reduced without increasing the cost, and the rotation speed when the lever contacts the contact portion can be reduced. Since it can be delayed, the contact noise of the lever can be reduced.

  In addition, by making the lever abut on the toothless gear via the cushioning material, it becomes possible to reduce the movable stroke of the lever, and the rotation speed of the lever when the lever abuts against the cushioning material can be reduced. It is possible to reduce the contact noise.

  According to the configurations of the first to third embodiments described above, the contact portion 82e (282e) is provided on the missing tooth gear 82 (282). The contact portion 82e limits the operating range in which the lever 81a operates when the lever 81a is retracted from the engagement position to the retracted position by the solenoid 81. Therefore, the movable stroke of the lever 81a is reduced, and the rotation speed of the lever 81a when the lever 81a contacts the contact portion 82e (282e) is decreased. As a result, the contact sound of the lever 81a is reduced without increasing the cost.

  According to the configuration of the second embodiment, when the lever 81a comes into contact with the contact portion 282e by the action of the solenoid 81, the contact force with which the lever 81a comes into contact with the contact portion 282e is absorbed by the contact portion 282e. As a result, the contact sound of the lever 81a is further reduced.

22 Drive gear 52, 252 ... Clutch mechanism 81 Solenoid (retracting means)
81a Lever (locking member)
81e Tension spring (return means)
82, 282 ... Missing gear 82b Missing tooth part 82c Cam 82d Engaging part 82e, 282e ... Contact part (restriction part)
87 Tension spring (Rotation biasing means)

Claims (7)

A notch gear that has a cam and partly has a tooth missing portion and is rotatable by meshing with the drive gear at the toothed portion ;
Rotating means for applying a rotational force to the segmented gear in order to mesh the segmented gear with the drive gear;
A locking member that engages with an engaging portion provided on the cam and stops rotation of the toothless gear ;
A retracting means for retracting the locking member from an engaging position engaging with the engaging portion to a retracting position retracted from the engaging portion;
Return means for returning the locking member from the retracted position to the engaged position;
With
A restriction portion is provided for restricting an operating range of the locking member when the locking member is retracted to the partial gear by the retracting means, and the locking member rotates with the rotation of the partial gear. A clutch mechanism characterized in that a passage part for allowing the restriction part to pass therethrough is provided.   The clutch mechanism according to claim 1, wherein the retracting means is a solenoid, and the return means is a spring. The clutch mechanism according to claim 1 or 2, wherein the limiting portion is configured integrally with the toothless gear .   The clutch mechanism according to any one of claims 1 to 3, wherein the passage portion is a notch portion formed in the locking member. The clutch mechanism according to any one of claims 1 to 4 , wherein the restricting portion is a buffer member. An image reading unit for reading an image;
The clutch mechanism according to any one of claims 1 to 5 ,
An image reading apparatus comprising: An image forming unit for forming an image;
The clutch mechanism according to any one of claims 1 to 5 ,
An image forming apparatus comprising:

Images