JP2018179171A - Speed switching device, drive device, sheet conveying device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed switching device, a driving device, a sheet transporting device and an image forming device capable of downsizing the device. A first final drive transmission member such as a first output gear 6a to which a driving force is finally transmitted in a first drive transmission path D1 having a first electromagnetic clutch 5 and a one-way clutch 4 are provided. A second final drive transmission member such as a second output gear 6b to which the driving force is finally transmitted in the second drive transmission path D2 having a reduction ratio larger than that of the drive transmission path D1 is provided coaxially. Further, a first drive transmission member such as the first input gear 7 for transmitting the driving force to the first final drive transmission member and a second drive such as the second input gear 3 for transmitting the driving force to the second final drive transmission member. The transmission member is provided coaxially. [Selection diagram] Fig. 2

Description

  The present invention relates to a speed switching device, a driving device, a sheet conveying device, and an image forming apparatus.

  The driving means of the drive source is transmitted by the control means to the first drive transmission path having a small reduction ratio among the two drive transmission paths having different reduction ratios and transmitting the driving force of the drive source to the output target rotor side. There is known a speed switching device provided with an electromagnetic clutch serving as drive transmission switching means for selectively switching between a state and a shutoff state, and providing a one-way clutch in a second drive transmission path having a large reduction ratio.

  In the patent document 1, as the speed switching device, a first drive transmission member for transmitting the driving force to a first final drive transmission member to which the driving force is finally transmitted in the first drive transmission path, and a second drive transmission path Finally, at the end, the drive force is transmitted, and the second drive transmission member arranged coaxially with the first drive transmission member is provided with different axes from the second drive transmission member for transmitting the drive force. ing.

  However, in Patent Document 1 described above, there is a possibility that the speed switching device may be enlarged.

  In order to solve the above problems, according to the present invention, of the two drive transmission paths having different reduction ratios and transmitting the driving force of the drive source to the output target rotor, the first drive transmission path having a small reduction ratio is used. In a speed switching device provided with a drive transmission switching means which is selectively controlled to switch between a state for transmitting the driving force and a state for shutting off by the control means, and a second drive transmission path having a large reduction ratio. A first drive transmission member for transmitting the driving force to a first final drive transmission member to which the driving force is finally transmitted in the first drive transmission path, and the driving force in the last in the second drive transmission path A second drive transmission member for transmitting the driving force to the second final drive transmission member which is transmitted and coaxially arranged with the first final drive transmission member is provided coaxially. Ah .

  According to the present invention, the device can be miniaturized.

FIG. 1 is a schematic configuration view showing one configuration example of an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view of a drive device according to a first embodiment. The schematic block diagram of a 1st electromagnetic clutch. The control flow figure showing an example of control of a drive. FIG. 7 is a schematic cross-sectional view of a drive device according to a second embodiment. FIG. 10 is a schematic cross-sectional view of a drive device according to a third embodiment. FIG. 10 is a schematic configuration diagram of a drive device according to a fourth embodiment. The schematic block diagram of the drive device of Example 4 which removed each bearing from the bracket. FIG. 14 is a schematic configuration diagram of a drive device according to a fifth embodiment. The schematic block diagram of the drive device of Example 5 which removed each bearing from the bracket. FIG. 16 is a schematic configuration diagram of a drive device according to a sixth embodiment. The schematic block diagram of the drive device of Example 6 which removed each bearing from the bracket. FIG. 18 is a schematic cross-sectional view of a drive device according to a seventh embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration view showing an example of the configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 is an electrophotographic image forming apparatus, and includes an apparatus main body 200 which is a printing unit, and an image reading apparatus 300. Although the electrophotographic image forming apparatus 100 will be described in this embodiment, the image forming system in the image forming apparatus 100 may be another system such as an inkjet system.

  The apparatus main body 200 is a sheet as a recording medium supplied from a paper feeding apparatus 210 as a sheet supply unit based on image data of an image read by the image reading apparatus 300 and image data sent from an external apparatus. A toner image is formed on a certain sheet (recording sheet) 400.

  The image reading apparatus 300 includes an automatic document feeder (ADF) 310 as a sheet conveying apparatus, and a scanner unit 320. The automatic document feeder 310 sends out a document 410 which is a sheet set as the image reading target set by the user, and the scanner unit 320 reads an image of the document 410 sent from the automatic document feeder 310.

  The thickness of the sheet such as the sheet 400 to be conveyed and the document 410 is, for example, 50 μm to 500 μm. Sheets such as paper 400 and original 410, which are generally called high-quality paper and have a thickness of about 100 μm (for example, 100 μm ± 10 μm), are also transported.

  An apparatus main body (print unit) 200 includes four image forming units 46 Y, M, C, and K for forming toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). Is equipped. These toners use different colors Y, M, C, K toner as an image forming material, but other than that, they have the same configuration and are replaced when their lifetime is reached. The image forming units 46Y, M, C, and K each include a drum-like photosensitive member as a latent image carrier, a drum cleaning device as a photosensitive member cleaning device, a charge removing device, a charging device, a developing device, and the like. These imaging units are detachable from the apparatus main body 200 so that consumable parts can be replaced at one time.

  An optical writing unit 47 is disposed below the image forming units 46Y, M, C, and K in FIG. The optical writing unit 47 as a latent image forming unit irradiates and exposes the photosensitive members in the image forming units 46Y, M, C, and K with laser light L emitted based on image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the respective photosensitive members. The optical writing unit 47 is photosensitive through a plurality of optical lenses and mirrors while deflecting laser light emitted from a light source in the main scanning direction (photosensitive member axial direction) by a polygon mirror rotationally driven by a motor. Irradiate the body.

  Below the optical writing unit 47, a sheet feeding device 210 having a sheet storage cassette 26 and a separation unit 27 incorporated therein is disposed. The sheet storage cassette 26 stores sheets of paper 400 in the form of a sheet bundle. Further, the separation means 27 forms a separation nip by the feed roller 27a that can be rotationally driven and the separation pad 27b that is in contact with the feed roller 27a.

  A feed roller 27 a of the separating unit 27 is in contact with the top sheet 400 of the sheet bundle in the sheet storage cassette 26. The feed roller 27a feeds the sheet 400 into the separation nip by its own rotational drive. When a plurality of sheets of paper 400 are fed into the separation nip in an overlapping state, the feed roller 27a contacts only the uppermost sheet 400 of the sheets. The uppermost sheet 400 moves in the feeding direction in the separation nip following the surface movement of the feed roller 27a. On the other hand, a load resistance is applied to the lower sheet excluding the uppermost sheet 400 by the separation pad 27b which does not move on the surface. As a result, the lower sheet 400 can not move in the feed direction following the top sheet 400 and stays in the separation nip. In this manner, the separating unit 27 separates only the uppermost sheet 400 of the plurality of sheets 400 fed out from the sheet storage cassette 26 into one sheet, and the first sheet conveyance path Feed toward the paper feed path 250).

  Near the middle point in the length direction of the paper feed path, a conveyance roller pair 28 as a conveyance means is disposed. The conveyance roller pair 28 forms a conveyance nip by bringing a first conveyance roller 28 a as a conveyance member into contact with a second conveyance roller 28 b as a conveyance member. Among the two conveying rollers, at least the first conveying roller 28a is rotationally driven by the driving means.

  In the vicinity of the end in the length direction of the paper feed path, a registration roller pair 29 as a butting conveyance means is disposed. The registration roller pair 29 includes a first registration roller 29a as a butting conveyance member, and a second registration roller 29b that abuts on the first registration roller 29a and forms a registration nip as a butting conveyance nip. At least a first registration roller 29 a of the two registration roller pairs 29 is rotationally driven by a driving device as a driving unit described later.

  The first transport roller 28 a of the transport roller pair 28 starts rotational drive substantially simultaneously with the start of rotational drive of the feed roller 27 a of the separation unit 27 or with a slight time lag. The leading end of the sheet 400 fed from the separation nip of the separation unit 27 to the sheet feeding path is eventually pinched by the conveyance nip of the conveyance roller pair 28. Since the first conveyance roller 28a is rotationally driven at a higher rotational speed than the feed roller 27a, at this time, the sheet 400 is tensioned with strong tension between the separation nip and the conveyance nip. Then, when a strong torque is applied to the feed roller 27 a, the torque limiter operates to cause the feed roller 27 a to move along with the sheet 400. At this time, when the torque limiter operates irregularly, back tension is irregularly applied to the sheet 400. Then, the sheet 400 causes a slip on the first conveyance roller 28a, thereby promoting the wear of the first conveyance roller 28a.

  Thereafter, the sheet 400 is fed from the inside of the conveyance nip toward the registration roller pair 29 by the rotational drive of the first conveyance roller 28 a, and then the front end thereof abuts against the registration nip of the registration roller pair 29. At this time, since the rotational driving of the registration roller pair 29 is stopped, the sheet 400 can not enter into the registration nip, and gradually bends. By this deflection, the skew of the sheet 400 is corrected.

  After the sheet 400 is fed out from the transport nip of the transport roller pair 28, when the predetermined timing comes, the rotational driving of the feed roller 27a of the separating unit 27 and the rotational drive of the transport roller pair 28 are stopped. As a result, the conveyance of the sheet 400 is temporarily stopped in a state in which the leading end is bent.

  Above the image forming units 46Y, M, C, and K in the drawing, an intermediate transfer unit 55 is disposed for endlessly moving the intermediate transfer belt 48 as an intermediate transfer member while stretching it. The intermediate transfer unit 55 includes, in addition to the intermediate transfer belt 48, four primary transfer bias rollers 49Y, M, C, and K, a belt cleaning device 50, and the like. The secondary transfer backup roller 52, the cleaning backup roller 53, the tension roller 54 and the like are also provided.

  The intermediate transfer belt 48 is endlessly moved counterclockwise in the figure by rotational driving of at least one of the rollers while being stretched over three rollers inside the loop. The primary transfer bias rollers 49Y, M, C, and K sandwich the intermediate transfer belt 48 thus endlessly moved between the photosensitive members 41Y, M, C, and K to form primary transfer nips. In these systems, a transfer bias of the opposite polarity (for example, plus) to the toner is applied to the back surface (inner peripheral surface of the loop) of the intermediate transfer belt 48. All the rollers except the primary transfer bias rollers 49Y, M, C, and K are electrically grounded. The intermediate transfer belt 48 sequentially passes the primary transfer nips for Y, M, C, and K along with the endless movement, and Y, M, C, and Y on the photosensitive bodies 41 Y, M, C, and K. The K toner image is superimposed and primarily transferred. Thereby, a four-color superimposed toner image (hereinafter, referred to as a four-color toner image) is formed on the intermediate transfer belt 48.

  The secondary transfer backup roller 52 disposed inside the belt loop sandwiches the intermediate transfer belt 48 with the secondary transfer roller 59 disposed outside the belt loop to form a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 48 is transferred to the sheet 400 at the secondary transfer nip. On the intermediate transfer belt 48 after passing through the secondary transfer nip, transfer residual toner which has not been transferred to the sheet 400 is attached. This is cleaned by the belt cleaning device 50.

  After the rotational driving of the feed roller 27a and the conveyance roller pair 28 is temporarily stopped, when it is time to synchronize the sheet 400 with the four-color toner image on the intermediate transfer belt 48 in the secondary transfer nip, the feed roller 27a or The rotational drive of the transport roller pair 28 is resumed. Further, the rotational drive of the registration roller pair 29 is started. As a result, the sheet 400 is nipped by the registration nip of the pair of registration rollers 29, and then fed from the registration nip to the secondary transfer nip. Then, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 48 is superimposed.

  The sheet 400 delivered from the secondary transfer nip is transferred to the surface by heat and pressure when passing between the fixing roller pair 230 constituted by the fixing roller 230 a and the pressure roller 230 b of the fixing device 20. The four-color toner image is fixed. Thereafter, the sheet 400 passes between the rollers of the sheet discharge roller pair 30 and is discharged to the outside of the machine. A stack unit 31 is formed on the upper surface of the apparatus main body 200, and the sheets 400 discharged to the outside by the discharge roller pair 30 are sequentially stacked on the stack unit 31.

  A bottle container 33 is disposed between the intermediate transfer unit 55 and the stack unit 31 located above the intermediate transfer unit 55. The bottle container 33 accommodates toner bottles 32Y, 32M, 32C, and 32K as replenishment toner storage units for storing Y, M, C, and K toners. The toner bottles 32Y, 32M, 32C, and 32K are placed on the bottle holder 33 from above for each color of toner. The Y, M, C, and K toners in the toner bottles 32Y, M, C, and K are appropriately supplied to the developing devices of the image forming units 46Y, M, C, and K by toner replenishing devices as toner conveying means described later. Be done. The toner bottles 32Y, 32M, 32C, and 32K are detachable from the apparatus main body 200 independently of the imaging units 46Y, 46M, 46C, and 46K.

  In the vicinity of the fixing device 20, a switchback device is disposed. In the duplex printing mode in which an image is formed on both sides of the sheet 400, the sheet 400 which has passed through the fixing device 20 after the toner image is formed on only one side is turned upside down by the switchback device. The sheet 400, which has been turned upside down, is resent toward the registration nip of the registration roller pair 29 via the inversion path 254. Then, after the toner image is formed on the other side by being sent from the resist nip to the secondary transfer nip, the toner image on the other side is fixed by the fixing device 20, and then the paper discharge roller It is stacked on the stack unit 31 via the pair 30.

  On the apparatus main body (print unit) 200, as described above, the image reading apparatus 300 including an automatic document feeder (ADF) 310 and a scanner unit 320 is disposed. The image reading apparatus 300 is fixed on a mount 199 supported by two legs fixed to the back of the apparatus main body 200, and between the stack part 31 of the apparatus main body 200 and the mount 199 A large space intervenes. The sheet 400 stacked on the stack unit 31 is located in the space.

  The scanner unit 320 of the image reading apparatus 300 includes a fixed reading unit 321 and a movement reading unit 322. The moving reading unit 322 is disposed immediately below the second contact glass fixed to the upper wall of the casing of the scanner unit 320 so as to contact the document 410, and an optical system including a light source and a reflection mirror is shown in the figure. It can be moved in the left and right direction. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected by the surface of the document 410 placed on the second contact glass, and then passes through a plurality of reflection mirrors. The image reading sensor 323 fixed to the scanner body receives the light.

  On the other hand, the fixed reading unit 321 has a light source, a reflecting mirror, an image reading sensor 323 such as a CCD, and the like, and the first contact glass fixed on the casing upper wall of the scanner unit 320 to contact the document 410. It is arranged directly below. Then, when the document 410 conveyed by the automatic document feeder 310 passes over the first contact glass, the image reading sensor is caused to pass through a plurality of reflecting mirrors while sequentially reflecting the light emitted from the light source on the document surface To receive light. Thus, the first surface of the document 410 is optically scanned without moving the optical system including the light source and the reflection mirror. The automatic document feeder 310 is provided with a second surface reading sensor that optically scans the second surface of the document 410.

  When a document bundle in which a plurality of documents 410 are stacked is set in the automatic document feeder 310, the documents 410 can be automatically conveyed one by one. Then, the fixed reading unit 321 in the scanner unit 320 and the second surface fixed reading unit in the automatic document feeder 310 can sequentially read the image of the document 410 automatically conveyed one by one. In this case, after the original bundle is set on the original table 311, the copy start button is pressed. Then, the automatic document feeder 310 conveys the document 410 of the document bundle placed on the document placement table 311 in order from the top. In the process of this conveyance, the document 410 is passed immediately above the fixed reading unit 321 of the scanner unit 320 immediately after the document 410 is reversed. At this time, the image on the first surface of the document 410 is read by the fixed reading unit 321 of the scanner unit 320.

  In the image forming apparatus 100 configured as described above, the apparatus main body 200 includes first to third sheet conveyance paths 250, 252, and 253 as sheet conveyance paths for conveying the sheet 400. In the first sheet conveyance path 250, the sheet 400 delivered from the sheet feeding device 210 by the feed roller 27 a passes through the pair of conveyance rollers 28 and the pair of registration rollers 29 to the secondary transfer backup roller 52 and the secondary transfer roller 59. Are conveyed to the secondary transfer position where they are facing each other. At the secondary transfer position, the toner image formed on the intermediate transfer belt 48 is transferred to the sheet 400. In the second sheet conveyance path 252, the sheet 400 on which the toner image is formed at the image forming position passes through the nip portion of the fixing roller pair 230 of the fixing portion that fixes the toner image, and passes the sheet discharge roller pair 30. The sheet is conveyed so as to be discharged onto the stack unit 31. In the third sheet conveyance path 253, the sheet 400 that has passed through the nip portion of the fixing roller pair 230 is conveyed to the reverse path 254 in order to form an image on both sides of the sheet 400.

  The image reading apparatus 300 has an original conveyance path 330 as a sheet conveyance path for conveying the original 410. In the document conveyance path 330, the document 410 fed from the automatic document feeder 310 is conveyed to the image reading position of the scanner unit 320.

  Next, an example of a drive device provided in the present printer will be described.

Example 1
FIG. 2 is a schematic cross-sectional view of the drive device 60 according to the first embodiment.
The driving device 60 according to the first embodiment drives the fixing roller 230a, the first registration roller 29a, and the feed roller 27a.
A motor 1 serving as a drive source for driving the fixing roller 230a, the first registration roller 29a, and the feed roller 27a is fixed to the surface of the bracket 8 opposite to the surface on the roller side. The motor shaft of the motor 1 passes through the bracket 8, and teeth are formed on the outer periphery of the motor shaft to form a motor gear 1a.

  Between the bracket 8 and the side plate 9 facing the roller-side surface of the bracket 8, the drive transmission is performed to the first drive transmission mechanism 61 for transmitting the drive to the fixing roller 230a, and to the first registration roller 29a and the feed roller 27a. And a second drive transmission mechanism 62 for

  The first drive transmission mechanism 61 includes a fixing idler gear 2 and a fixing gear 10. The fixing idler gear 2 is rotatably supported by a first fixed shaft S1 fixed to the bracket 8 and the side plate 9, and a first external gear 2a meshing with the motor gear 1a and a second external gear meshing to the fixing gear 10. And a gear 2b. The fixing gear 10 is attached so as to rotate integrally with the fixing shaft T of the fixing roller 230a rotatably supported by the side plate 9 via the bearing 9a.

  The second drive transmission mechanism 62 has a resist sheet feeding input gear 11, a speed switching mechanism D as a speed switching device, a resist gear 13, a resist electromagnetic clutch 12, a sheet feeding idler gear 14, a sheet feeding gear 16, and a sheet feeding electromagnetic clutch 15. doing. The resist sheet feeding input gear 11 is attached to the rotation axis X so as to rotate integrally with the rotation axis X rotatably supported by the bracket 8 and the side plate 9 via the bearings 8 b and 9 b.

  The speed switching mechanism D has two drive transmission paths having different reduction ratios. The first drive transmission path D1 is an input drive transmission member, a first input gear 7 as a first drive transmission member, a first output gear 6a as a first final drive transmission member, and a first electromagnetic as a drive transmission switching means And a clutch 5. The second drive transmission path D2 has a second input gear 3 which is an input drive transmission member and is a second drive transmission member, a second output gear 6b which is a second final drive transmission member, and a one-way clutch 4 There is.

The first input gear 7, the first electromagnetic clutch 5, and the one-way clutch 4 are provided on the rotation axis X, and the second input gear 3 is fixed to the outer peripheral surface of the one-way clutch 4. The first electromagnetic clutch 5 is engaged with the first input gear 7 in the axial direction.
The one-way clutch 4 can transmit the driving force between the rotation axis X and the second input gear 3 when the rotation axis X rotates forward relative to the one-way clutch 4, and the rotation axis X Is reversely rotated relative to the one-way clutch 4, it is configured to rotate idle with respect to the rotation axis X.

  The first output gear 6a and the second output gear 6b are integrally configured, and the drive output member 6 which is an integral unit thereof is rotatably supported by an output fixing shaft U fixed to the bracket 8 and the side plate 9 ing.

  The resist gear 13 and the resist electromagnetic clutch 12 are provided on the resist axis Y of the first resist roller 29 a rotatably supported by the side plate 9 and the bracket 8 via the bearings 9 c and 8 c. The resist gear 13 is rotatably supported on the resist axis Y, and meshes with the second output gear 6b. The resist electromagnetic clutch 12 is fixed to the resist axis Y so as to rotate integrally with the resist axis Y, and is engaged with the resist gear 13 from the axial direction.

  The sheet feed idler gear 14 meshes with the registration gear 13. The paper feed idler gear 14 is rotatably supported by a second fixed shaft S2 fixed to the bracket 8 and the side plate 9. The paper feed gear 16 is engaged with the paper feed idler gear 14. The sheet feeding gear 16 and the sheet feeding electromagnetic clutch 15 are provided on a shaft Z of a feed roller 27a rotatably supported by the side plate 9 and the bracket 8 through bearings 9d and 8d. The sheet feeding gear 16 is rotatably supported by the axis Z of the feed roller 27a, and the sheet feeding electromagnetic clutch 15 is fixed to the axis Z so as to rotate integrally with the axis Z, from the axial direction It is engaged with the feed gear 16.

FIG. 3 is a schematic configuration diagram of the first electromagnetic clutch 5.
The first electromagnetic clutch 5 includes a shaft fixing portion 5e, an electromagnetic coil portion 5d, a rotor portion 5c, an armature 5b, a drive connecting member 5f, and the like. The shaft fixing portion 5e has an insertion hole into which the rotation axis X is inserted, and the cross section of the insertion hole has a substantially rounded square shape in which a part of a circular shape is cut out. The rotation axis X has a substantially rectangular quadrangular cross-section similar in shape to the insertion hole so as to be fitted into the insertion hole. The substantially rectangular cross section of the rotation axis X extends to a point where the first electromagnetic clutch 5 is attached. The shaft fixing portion 5e is fixed so as to rotate with the rotation axis X by fitting the cross section of the shaft fixing portion 5e to the cross section substantially square shape of the rotation axis X. .

  An electromagnetic coil portion 5d is rotatably attached to the shaft fixing portion 5e at the shaft fixing portion 5e. On the other hand, the rotor portion 5c is fixed to the shaft fixing portion 5e so as to rotate integrally with the shaft fixing portion 5e. The armature 5b is attached to a drive connecting member 5f having a pair of drive claws 5a extending toward the second resist output gear. A pair of drive connection holes 7a are formed on the surface of the first input gear 7 facing the first electromagnetic clutch 5, and drive claws 5a of the drive connection member 5f are fitted in these drive connection holes 7a. . As a result, the first electromagnetic clutch 5 and the first input gear 7 are integrally rotatable.

  When the first electromagnetic clutch 5 is turned off, the drive connecting member 5f is in a free state, and can freely rotate with respect to the shaft fixing portion 5e. Thereby, the drive transmission from the rotation axis X to the first input gear 7 is interrupted, and the drive connecting member 5 f and the first input gear 7 idle with respect to the rotation axis X.

  When the clutch is turned on, a current flows through the electromagnetic coil unit 5d to generate an electromagnetic force. When the electromagnetic force is generated, the armature 5b of the metal disk is attracted to the electromagnetic coil 5d by the electromagnetic force, and the drive connecting member 5f integral with the armature 5b slides toward the rotor 5c. Then, the armature 5 b is attracted to the rotor portion 5 c, and is transmitted from the rotation axis X to the first input gear 7 division motive power via the first electromagnetic clutch 5.

  The first electromagnetic clutch 5 may be provided so as to be able to slide the drive connecting member 5 f in the axial direction, and the first input gear 7 may be made rotatable with respect to the rotation axis X. Thereby, the gap with the rotation axis X can be made smaller than when the first input gear 7 is configured to be slidable in the axial direction. Thereby, the first input gear 7 can be prevented from tilting with respect to the rotation axis X.

  The resist electromagnetic clutch 12 and the sheet feeding electromagnetic clutch 15 have the same configuration as the first electromagnetic clutch 5.

  In the present embodiment, the reduction ratio of the second drive transmission path D2 having the one-way clutch 4 is made larger than the reduction ratio of the first drive transmission path D1. With this configuration, when the first electromagnetic clutch 5 is ON, the second input gear 3 and the one-way clutch 4 rotate faster than the rotation axis X, and the rotation axis X rotates in reverse relative to the one-way clutch 4 . Therefore, the second input gear 3 and the one-way clutch 4 idle with respect to the rotation axis X. Thereby, the driving force is input to the resist gear 13 via the first drive transmission path D1.

  On the other hand, when the second electromagnetic clutch 5 is off, the drive transmission from the first input gear 7 to the first output gear 6a is interrupted. Therefore, the driving force is not transmitted from the second output gear 6 b to the second input gear 3. Therefore, in this case, the rotation axis X rotates forward relative to the one-way clutch 4. Thus, the driving force is transmitted from the rotation axis X to the second input gear 3, and the driving force is input to the registration gear 13 via the second drive transmission path D <b> 2.

  As described above, by setting the speed reduction ratio of the second drive transmission path D2 having the one-way clutch 4 larger than the speed reduction ratio of the first drive transmission path D1, the rotation axis X is turned on with the first electromagnetic clutch 5 ON / OFF. The relative movement direction with respect to the one-way clutch 4 can be switched. Thus, the drive transmission state of the one-way clutch 4 can be switched by turning on / off the first electromagnetic clutch 5.

  Table 1 below shows an example of specifications of each gear of the speed switching mechanism D according to the first embodiment.

  As shown in Table 1 above, the reduction ratio of the first drive transmission path D1 is (81/82) = 0.987, and the reduction ratio of the second drive transmission path D2 is (97/98) = 0. 989, and the reduction ratio of the second drive transmission path D2 is larger than the reduction ratio of the first drive transmission path D1.

  For example, when the rotation axis X is rotating at 500 [rpm] and the first electromagnetic clutch 5 is ON, the driving force of the rotation axis X is transmitted through the first electromagnetic clutch 5 to the first input gear 7, It is transmitted from the first input gear 7 to the first output gear 6a. As a result, the drive output member 6 in which the first output gear 6a and the second output gear 6b are formed rotates at 506.2 [rpm] (= 500 [rpm] × (82/81)).

  Further, the driving force is transmitted from the second output gear 6b to the second input gear 3, and the second input gear 3 is rotationally driven. The rotation speed of the second input gear 3 at this time is 501 [rpm] (= 506.2 [rpm] × (97/98)), and rotates faster than the rotation axis X (500 [rpm]). As a result, with respect to the one-way clutch 4 that rotates integrally with the second input gear 3, the rotation axis X relatively reversely rotates, and the one-way clutch 4 idles with respect to the rotation axis X. Thereby, the transmission of the driving force from the second input gear 3 to the second output gear 6b is shut off, and the driving force is transmitted to the registration gear 13 via the first drive transmission path D1.

  On the contrary to the above, when the reduction ratio of the second drive transmission path D2 is smaller than the reduction ratio of the first drive transmission path D1, the rotational speed of the second input gear 3 becomes slower than the rotation axis X I will. As a result, with respect to the one-way clutch 4, the rotation axis X rotates relatively positively. Therefore, in this case, the relative rotational direction of the rotation axis X with respect to the one-way clutch 4 can not be switched between the electromagnetic clutch ON and OFF. As a result, even when the first electromagnetic clutch is ON, the one-way clutch 4 does not idle with respect to the rotation axis X, and the transmission of the driving force from the second input gear 3 to the second output gear 6b is not interrupted.

  On the other hand, in the first embodiment, the reduction ratio of the second drive transmission path D2 is made larger than the reduction ratio of the first drive transmission path D1. The relative rotation direction of can be switched from forward rotation to reverse rotation. Thereby, the transmission of the driving force from the second input gear 3 to the second output gear 6b can be cut off.

  As described above, in the first embodiment, the drive transmission path can be selectively switched between the one-way clutch 4 and the first electromagnetic clutch 5. The one-way clutch 4 is generally cheaper than the electromagnetic clutch. Therefore, the apparatus can be made inexpensive as compared with the one in which the drive transmission path is selectively switched by providing an electromagnetic clutch in each of the drive transmission paths. Further, since the one-way clutch 4 does not consume power, the power consumption of the device can be suppressed as compared with the case where the electromagnetic clutch is provided in each drive transmission path.

  In the first embodiment, the one-way clutch 4 and the first electromagnetic clutch 5 are provided on the rotation axis X, and the one-way clutch 4 and the first electromagnetic clutch 5 are provided coaxially. The one-way clutch 4 and the first electromagnetic clutch 5 need to be provided on a rotary shaft rotatably supported by the side plate 9 and the bracket 8 via bearings. Therefore, in the case where they are provided on mutually different shafts, two rotation shafts are required, and a total of four bearings are required. On the other hand, when the one-way clutch 4 and the first electromagnetic clutch 5 are provided coaxially, only one rotation shaft is required, and the one-way clutch 4 and the first electromagnetic clutch 5 are provided on different shafts. Two bearings can be reduced. Therefore, compared with the case where the one-way clutch 4 and the first electromagnetic clutch 5 are provided on shafts different from each other, the number of parts can be reduced, and the cost increase of the device can be suppressed.

  Further, by providing the one-way clutch 4 and the first electromagnetic clutch 5 on the rotation axis X on which the first input gear 7 and the second input gear 3 are disposed, the first output gear 6a disposed on the output fixed shaft U, The two output gears 6b can be integrated. As a result, the number of parts can be reduced and the number of assembling steps can be reduced as compared to the configuration in which the first output gear 6a and the second output gear 6b are separate. Further, the shaft supporting the first output gear 6a and the second output gear 6b can be a fixed shaft. As a result, the bearing can be eliminated, and the number of parts can be reduced as compared with the case of using the rotating shaft, and the apparatus can be made inexpensive.

  Further, in the present embodiment, the second output gear 6b is engaged with the registration gear 13 as the output target rotating body so that the driving force is transmitted from the second output gear 6b to the registration gear 13. Thereby, the number of parts can be reduced as compared with the case where a gear for outputting the driving force is provided to the registration gear 13 separately from the second output gear 6b. Further, in the present embodiment, the second output gear 6b is engaged with the registration gear 13, but the first output gear 6a may be engaged with the registration gear 13.

  Further, in the present embodiment, the image forming speed is changed according to the type of the sheet 400, and the sheet 400 passes through the secondary transfer nip and the fixing nip at a conveyance speed suitable for obtaining high image quality. There is. For example, in the case of thick paper, the thick paper transport mode, which is the second drive mode in which the rotational speed of the secondary transfer roller 59 and the rotational speed of the fixing roller 230a are slower than in the case of plain paper, is selected. The speed of the sheet 400 passing through the nip portion of the roller pair 230 is reduced. In addition, the first registration roller 29 a has a speed ratio to the rotational speed of the secondary transfer roller 59 so that the paper does not become pulled over or fed excessively between the registration roller pair 29 and the secondary transfer roller 59. The rotation speed is changed so as to be maintained at the same speed ratio as in the case of plain paper.

  The relationship between the rotational speeds of the respective rollers is as follows, based on the rotational speed of the secondary transfer roller 59. That is, assuming that the rotational speed of the secondary transfer roller 59 in the case of plain paper is Vf, the rotational speed of the first registration roller 29a is Vf × (1 + α), and the rotational speed of the fixing roller 230a is Vf × (1 + β). It is a relationship. In the case of thick paper, the rotational speed of the secondary transfer roller 59 is changed from Vf to Vt (Vf> Vt), the rotational speed of the first registration roller 29a is Vf × (1 + α), and the rotational speed of the fixing roller 230a is The relationship is Vt × (1 + β + γ). For example, when α = 0.004, β = −0.006, γ = 0.006, and the rotational speed of the secondary transfer roller 59 for plain paper Vf = 178 [mm / s], the rotation of the fixing roller 230a The speed is 176.932 [mm / s], and the rotation speed of the first registration roller 29a is 178.712 [mm / s]. Therefore, the relative speed ratio between the first registration roller 29a and the fixing roller 230a at this time is about 1%.

  When the rotational speed Vt of the secondary transfer roller 59 for thick paper is set to a half speed 89 [mm / s] with respect to the rotational speed for plain paper, the rotational speed of the fixing roller 230a is 89 mm / S], and the rotation speed of the first registration roller 29a is 89.36 [mm / s]. Accordingly, the relative speed ratio between the first registration roller 29a and the fixing roller 230a at this time is about 0.4%.

  As described above, in the present embodiment, the relative speed ratio between the first registration roller 29 a and the fixing roller 230 a is different between plain paper and thick paper. Therefore, only by changing the rotational speed of the motor 1, only one of the fixing roller 230a and the first registration roller 29a can be set to the specified rotational speed. Therefore, in the present embodiment, the second drive transmission mechanism 62 of the drive device 60 is provided with the speed switching mechanism D provided with drive transmission paths of two systems having different speed transmission ratios. As a result, with regard to the fixing roller 230a, by adjusting the rotational speed of the motor 1, the fixing roller 230a can be made to have a specified rotational speed between plain paper and thick paper. On the other hand, for the first registration roller 29a, by switching the drive transmission path by the speed switching mechanism D, the relative speed ratio with the secondary transfer roller 59 in the case of thick paper can be made the same speed ratio as in the case of plain paper.

In the first embodiment, the number of teeth of the motor gear 1a is Z1, the number of teeth of the resist feeding input gear 11 is Z2, the number of teeth of the first input gear 7 is Z3, the number of teeth of the second input gear 3 is Z4, and Assuming that the number of teeth of one output gear 6a is Z5, the number of teeth of the second output gear 6b is Z6, and the number of teeth of the registration gear 13 is Z7, the reduction ratio V1 when performing drive transmission using the first drive transmission path D1 is , It becomes as follows.
V1 = (Z2 / Z1) × (Z5 / Z3) × (Z7 / Z6) ··· (1)

Further, the reduction ratio V2 when performing drive transmission using the second drive transmission path D2 is as follows.
V2 = (Z2 / Z1) × (Z6 / Z4) × (Z7 / Z6)
= (Z2 / Z1) x (Z7 / Z4) ... (2)

The relative reduction ratio (V1 / V2) [%] between when the first drive transmission path D1 is used and when the second drive transmission path D2 is used is as follows.
(V1 / V2) = [{(Z2 / Z1) × (Z5 / Z3) × (Z7 / Z6)}
/ {(Z2 / Z1) x (Z7 / Z4)}] x 100
= {(Z5 / Z3) x (Z4 / Z6)} x 100 (3)

  As understood from the above equation (3), the relative speed reduction ratio is determined by the speed reduction ratio (Z5 / Z3) of the first drive transmission path D1 and the speed reduction ratio (Z4 / Z6) of the second drive transmission path D2. Thus, in the present embodiment, the two gears (first input gear 7 and the first output gear 6a) of the first drive transmission path D1 and the two gears of the second drive transmission path D2 (second input gear 3) The relative reduction ratio can be adjusted by the second output gear 6b).

  As shown in Table 1 above, the reduction ratio of the first drive transmission path D1 is (81/82) = 0.987, and the reduction ratio of the second drive transmission path D2 is (97/98) = 0. 989, and the relative speed reduction ratio is 0.2%.

  As described above, in the first embodiment, the relative speed ratio can be 1% or less with less than 100 teeth of the gears constituting each drive transmission path. As a result, the relative speed ratio can be reduced to 1% or less by reducing the diameter of the gears of the drive transmission paths, and the apparatus can be miniaturized. This is because each drive transmission path is provided with a plurality of non-common gears. Thus, by providing a plurality of non-common gears in each drive transmission path, it is possible to make the module and twist angle of the gears different from each other in each drive transmission path, and the number of teeth is 100 or less. The relative speed ratio can be adjusted to 1% or less. The reason why a plurality of non-common gears are provided in each drive transmission path is as follows. That is, the one-way clutch 4 of the drive transmission path having the larger reduction ratio is provided, and the other side is provided with the electromagnetic clutch so that the drive transmission path can be selectively switched by ON / OFF of the electromagnetic clutch.

  Further, the speed switching mechanism D of the first embodiment is provided with the first output gear 6a and the second output gear 6b coaxially, and with the first input gear 7 for transmitting the driving force to the first output gear 6a. The second input gear 3 for transmitting the driving force to the second output gear 6b is also provided coaxially. Thus, the device can be miniaturized as compared with the case where either the output gear or the input gear of each drive transmission path is provided on different shafts. Further, in the first embodiment, by configuring each drive transmission path by two drive transmission members of the input gear and the output gear, the relative speed ratio is 1% or less with the minimum number of drive transmission members. There is. Thereby, the cost increase due to the increase in the number of parts can be suppressed.

  When the resist electromagnetic clutch 12 is ON, the driving force transmitted from the speed switching mechanism D to the resist gear 13 is transmitted to the resist axis Y via the resist electromagnetic clutch 12, and the first resist roller 29a is rotationally driven. The driving force transmitted to the registration gear 13 is input to the sheet feeding gear 16 via the sheet feeding idler gear 14. When the sheet feeding electromagnetic clutch 15 is ON, the driving force is transmitted to the axis Z of the feed roller 27a via the sheet feeding electromagnetic clutch 15, and the feed roller 27a is rotationally driven.

  In addition, with respect to the feed roller 27a to which the driving force is transmitted via the second drive transmission mechanism 62, the relative speed ratio to the first registration roller 29a so that the paper is not pulled between the registration roller pair 29 or fed excessively. It is necessary to change the rotational speed so that the same relative speed ratio is maintained for the plain paper and for the thick paper.

  In the first embodiment, as shown in FIG. 2 described above, the driving force is transmitted to the feed roller 27 a through the resist gear 13 which is a member to be output in which the speed switching mechanism D outputs the driving force. Thus, when the first electromagnetic clutch 5 is ON, the driving force is transmitted to the feed roller 27a via the first drive transmission path D1 as in the case of the first registration roller 29a. On the other hand, when the first electromagnetic clutch 5 is OFF, the driving force is transmitted to the feed roller 27a via the second drive transmission path D2. Thus, the speed of the feed roller 27a is changed by the speed switching mechanism D in the same manner as the first registration roller 29a, and the relative speed ratio between the feed roller 27a and the first registration roller 29a can be changed between thick paper and plain paper. From time to time, the same relative speed ratio can be maintained.

FIG. 4 is a control flowchart showing an example of control of the drive device 60. As shown in FIG.
First, the control unit of the image forming apparatus 100, which is a control unit, checks whether the conveyed sheet 400 is a thick sheet (S1). For example, when the sheet 400 is set in the sheet storage cassette 26, the information on the sheet thickness of the sheet 400 to be conveyed can be input by operating the operation display unit and inputting sheet thickness information of the sheet 400 set by the user. It can be grasped.

  When the sheet 400 being conveyed is not a thick sheet (No in S1), the first electromagnetic clutch 5 is turned off (S4), and the second drive transmission path D2 is used to the first registration roller 29a and the feed roller 27a. Set to transmit driving force. Then, the motor 1 is driven at the first rotation speed Vb (the plain paper conveyance mode which is the first drive mode) (S5). Thus, the fixing roller 230a, the first registration roller 29a, and the feed roller 27a are rotationally driven at a predetermined speed ratio with respect to the rotational speed Vf of the secondary transfer roller 59.

  On the other hand, when the sheet to be conveyed is thick (Yes in S1), the first electromagnetic clutch 5 is turned on (S2), and the first drive transmission path D1 is used for the first registration roller 29a and the feed roller 27a. Set to transmit driving force. Then, the motor 1 is driven at a second rotation speed Va (thick paper conveyance mode which is a second drive mode) which is lower than the first rotation speed Vb (S3).

  By driving the motor 1 at a second rotation speed Va lower than the first rotation speed Vb, the fixing roller 230a is rotationally driven at a low rotation speed. As a result, even in the case of thick paper, the toner image on the sheet can be sufficiently heated in the fixing nip, and the toner image can be melted well, and good fixability can be obtained. In the present embodiment, the second rotational speed Va is reduced by 0.3% to 0.6% with respect to the first rotational speed Vb.

  On the other hand, in the case of thick paper, the driving force is transmitted to the first registration roller 29a and the feed roller 27a via the first drive transmission path D1, and the paper is rotationally driven. In the first drive transmission path D1, when the motor 1 is driven at the second rotational speed Va, the rotational speeds of the first registration roller 29a and the feed roller 27a are equal to the rotational speed Vt of the secondary transfer roller 59 when thick paper is used. On the other hand, the speed ratio is set to be the same as that for plain paper. As a result, even when the rotational speed of the motor 1 is reduced to reduce the rotational speed of the fixing roller 230a in the case of thick paper, the speed ratio between the registration roller pair 29 and the secondary transfer roller 59 can be maintained. As a result, even in the case of thick paper, the sheet can be favorably transported to the secondary transfer nip, and the toner image on the intermediate transfer belt 48 can be secondarily transferred onto the sheet 400.

  Further, the relative velocity ratio between the feed roller 27a and the first resist roller 29a is maintained at the same relative velocity ratio between the plain paper and the thick paper. As a result, it is possible to suppress the occurrence of sheet buckling or the like due to pulling of the sheet or excessive feeding of the sheet between the feed roller 27 a and the pair of registration rollers 29 at the time of plain paper conveyance or thick sheet conveyance.

  In FIG. 6, the first drive transmission path D1 is used for thick paper, and the second drive transmission path D2 is used for other than thick paper, but the second drive transmission path D2 is used for thick paper The first drive transmission path D1 may be used when other than thick paper. However, in the case of frequently used plain paper, it is preferable to use the second drive transmission path D2. This is because when the second drive transmission path D2 is used, the power consumption of the device can be suppressed because the first electromagnetic clutch 5 is OFF. In addition, the life of the first electromagnetic clutch 5, which is generally more expensive than a one-way clutch, can be extended, and the running cost of the device can be reduced.

  In the first embodiment, the first registration roller 29a and the feed roller 27a are rotationally driven by the second drive transmission mechanism 62. For example, the first registration roller 29a and the first conveyance roller 28a are used. May be transmitted by the second drive transmission mechanism 62. Alternatively, the drive transmission of the first registration roller 29 a, the first conveyance roller 28 a, and the feed roller 27 a may be performed by the second drive transmission mechanism 62. Alternatively, the driving force may be transmitted to the secondary transfer roller 59 and the first registration roller 29 a by the second drive transmission mechanism 62.

  Further, the speed switching mechanism D may be provided in the first drive transmission mechanism 61 for transmitting the driving force to the fixing roller 230a, but when reversely rotating the fixing roller 230a at the time of jam processing, the second driving of the speed switching mechanism D The transmission mechanism 62 is provided.

  As shown in FIG. 1, the fixing nip portion is covered by the case of the fixing device 20, and the fixing nip portion is not easily accessible to the user. Therefore, when the small size sheet jams in the fixing nip portion, the small size sheet is difficult to remove. Therefore, the image forming apparatus 100 performs a jam processing operation to reversely rotate the motor 1 and reversely rotate the fixing roller 230a when the small size sheet jams in the fixing nip portion. By performing the jam processing operation, the rear end of the sheet 400 can be exposed from the fixing device 20, and the sheet 400 can be easily taken out.

  On the other hand, even if the sheet is jammed by the registration roller pair 29 and the separating means 27, unlike the fixing device 20, the nip portion is not covered by the case, and the sheet 400 is jammed by the user without reverse rotation. Easy access to Therefore, the first registration roller 29a and the feed roller 27a can easily remove the sheet without reverse rotation at the time of jam processing.

  When the fixing roller 230a is reversely rotated at the time of jam processing, the motor 1 is reversely rotated. When the motor 1 is reversely rotated, if the first electromagnetic clutch 5 is OFF, the rotation axis X is reversely rotated relative to the one-way clutch 4, the second input gear 3 and the one-way clutch 4 are rotated. Idle around axis X Therefore, the driving force of the motor 1 is not transmitted. On the other hand, when the motor 1 is reversely rotated, when the first electromagnetic clutch 5 is turned ON, the rotation axis X rotates forward relative to the one-way clutch 4, so the driving force from the rotation axis X to the one-way clutch 4 Is transmitted. As a result, driving force is transmitted from both of the first input gear 7 and the second input gear 3 to the drive output member 6, stress is applied to each gear of the speed switching mechanism D, and problems such as breakage of teeth occur. There is a problem that there is a fear. Therefore, when the speed switching mechanism D is provided in the first drive transmission mechanism 61, the above-mentioned problem occurs.

  On the other hand, if the first electromagnetic clutch 5 is turned off by providing the second drive transmission mechanism 62 with the speed switching mechanism D, the motor 1 is reversely rotated to reversely rotate the fixing roller 230a. The driving force is not transmitted to the registration roller 29a and the feed roller 27a, and these rollers are not rotationally driven.

Example 2
FIG. 5 is a schematic cross-sectional view of a drive device 60A according to a second embodiment.
The second embodiment is a modification of the first embodiment, in which both the first drive transmission path D1 and the second drive transmission path D2 of the speed switching mechanism D are configured using a timing belt. The first drive transmission path D1 includes a first input pulley 71 supported on the rotation axis X, a first output pulley 61a provided on the output fixed shaft U, a first input pulley 71, and a first output pulley 61a. A first timing belt 72, which is a tensioned toothed belt, is provided. The first electromagnetic clutch 5 is engaged with the first input pulley 71 from the axial direction and attached to the rotation axis X.

  The second drive transmission path D2 includes a second input pulley 3a provided to the one-way clutch 4, a second output pulley 61b provided to the output fixed shaft U, a second input pulley 3a, and a second output pulley 61b. And a second timing belt 73 which is a tensioned toothed belt.

  Further, the output fixed shaft U is provided with an output gear 6c meshing with the registration gear 13. The output gear 6c, the first output pulley 61a and the second output pulley 61b are integrally configured, and The drive output member 6 which is an integral body is rotatably supported by the output fixed shaft U.

  Also in the second embodiment, the ratio of the number of teeth of the first input pulley 71 of the first drive transmission path D1 to the number of teeth of the first output pulley 61a of the first drive transmission path D1 and the second of the second drive transmission path D2. The relative reduction ratio is determined by the ratio between the number of teeth of the two-input pulley 3a and the number of teeth of the second output pulley 61b of the second drive transmission path D2. Therefore, when the first drive transmission path D1 is used according to the number of teeth of the first input pulley 71, the number of teeth of the first output pulley 61a, the number of teeth of the second input pulley 3a, and the number of teeth of the second output pulley 61b. The relative speed reduction ratio (V1 / V2) of when the second drive transmission path D2 is used can be adjusted.

  For example, a timing belt of S2M type is used as the timing belt of one drive transmission path, and a timing belt of S3M type is used as the timing belt of the other drive transmission path, and the tooth shape of the timing belt is made different from each other. The relative reduction ratio (V1 / V2) can be 1% or less when the number of teeth is 100 or less.

  Also in the second embodiment, the reduction ratio of the second drive transmission path D2 is set larger than the reduction ratio of the first drive transmission path D1. As a result, when the first electromagnetic clutch 5 is turned on, the second input pulley 3a rotates faster than the rotation axis X, and the rotation axis X reversely rotates relative to the second input pulley 3a. Thus, the one-way clutch 4 can idle with respect to the rotation axis X. On the other hand, when the first electromagnetic clutch 5 is OFF, only the rotation axis X is rotationally driven, so the rotation axis X rotates forward relative to the second input pulley 3a. Therefore, when the first electromagnetic clutch 5 is turned off, the driving force of the rotation axis X is transmitted to the second input pulley 3 a via the one-way clutch 4.

  Also in the second embodiment, the first input pulley 71 and the second input pulley 3a are provided coaxially, and the first output pulley 61a and the second output pulley 61b are provided coaxially, so that mutually different shafts are provided. The size of the device can be reduced as compared with the case where the device is provided.

Further, by configuring each drive transmission path using a timing belt, even if the first registration roller 29a is disposed at a position away from the motor 1, each drive transmission is performed by a gear train in which a plurality of gears are engaged. The number of parts can be reduced and drive transmission can be performed to the first registration roller 29a and the feed roller 27a as compared with the case where the path is configured. Thereby, the cost increase of the device can be suppressed.
As described in the first embodiment, by configuring each drive transmission path of the speed switching mechanism D by a gear train in which a plurality of gears are engaged, wear and the like as compared with the configuration using a timing belt. And the durability can be enhanced.

[Example 3]
FIG. 6 is a schematic cross-sectional view of a drive device 60B according to a third embodiment.
The drive device 60B according to the third embodiment is a modification of the first embodiment, and the first electromagnetic clutch 5 and the one-way clutch 4 are provided on shafts different from each other.
In the third embodiment, the second output gear 6b is engaged with the registration sheet input gear 11, and the registration sheet input gear 11 is used as an input gear of the second drive transmission path D2. Further, in the third embodiment, the second output gear 6 b is provided separately from the first output gear 6 a and provided on the outer peripheral surface of the one-way clutch 4. The one-way clutch 4 is provided on an output rotation shaft X2 rotatably supported by the side plate 9 and the bracket 8 via bearings 9e and 8e.

  The drive output member 6 includes a first output gear 6a and an output gear 6c which meshes with the resist gear 13 and outputs a drive force to the resist gear 13. The drive output member 6 is configured to rotate integrally with the output rotary shaft X2. Supported by X2. Further, in the one-way clutch 4 in the third embodiment, when the output rotation axis X2 rotates forward relative to the one-way clutch 4, the drive transmission from the second output gear 6b to the output rotation axis X2 is interrupted. The driving force is transmitted at the time of reverse rotation.

  When the first electromagnetic clutch 5 is OFF, the driving force is not input to the first input gear 7 via the first electromagnetic clutch 5, so the driving force is not transmitted from the first output gear 6a to the output rotation axis X2. The output rotation axis X2 is not rotationally driven. On the other hand, driving force is transmitted from the resist sheet feeding input gear 11 to the second output gear 6b, and the one-way clutch 4 is rotationally driven together with the second output gear 6b. As a result, the output rotation axis X2 rotates in reverse relative to the one-way clutch 4. In the third embodiment, as described above, the one-way clutch 4 drives from the second output gear 6b to the output rotation axis X2 when the output rotation axis X2 rotates in the reverse direction relative to the one-way clutch 4 Force is transmitted. Therefore, when the first electromagnetic clutch 5 is OFF, the driving force is transmitted from the second output gear 6b to the output rotation axis X2. Then, the driving force is transmitted to the registration gear 13 from the output gear 6c of the drive output member 6 which rotates integrally with the output rotation axis X2.

  On the other hand, when the first electromagnetic clutch 5 is ON, the driving force is input to the first input gear 7 via the first electromagnetic clutch 5, and the output rotation axis X2 is rotationally driven. Also in the third embodiment, the reduction ratio of the second drive transmission path D2 (the reduction ratio between the resist paper feed input gear 11 and the second output gear 6b) is set to the reduction ratio of the first drive transmission path D1 (first The reduction ratio between the input gear 7 and the first output gear 6a) is made larger. Therefore, the rotational speed of the output rotation axis X2 rotationally driven using the first drive transmission path D1 is faster than the rotational speed of the second output gear 6b. As a result, the output rotation axis X 2 rotates forward relative to the one-way clutch 4. As described above, in the one-way clutch 4 of the third embodiment, when the output rotating shaft X2 rotates forward relative to the one-way clutch 4, the driving force from the second output gear 6b to the output rotating shaft X2 is It is the composition which is intercepted. Accordingly, when the first electromagnetic clutch 5 is ON, the driving force is interrupted from the second output gear 6b to the output rotation axis X2, and passes through the first drive transmission path D1 to output the resist gear 13 from the output gear 6c of the drive output member 6. The driving force is transmitted to the

  Thus, also in the third embodiment, the drive transmission path can be selectively switched using the electromagnetic clutch and the one-way clutch.

In the third embodiment, the number of teeth of the motor gear 1a is Z1, the number of teeth of the resist sheet feeding input gear 11 is Z2, the number of teeth of the first input gear 7 is Z3, the number of teeth of the first output gear 6a is Z4, and the second Assuming that the number of teeth of the output gear 6b is Z5, the number of teeth of the output gear 6c is Z6, and the number of teeth of the registration gear 13 is Z7, the reduction ratios V1 and V2 using each drive transmission path are as follows.
V1 = (Z2 / Z1) × (Z4 / Z3) × (Z7 / Z6)
V2 = (Z2 / Z1) × (Z5 / Z2) × (Z7 / Z6)
= (Z5 / Z1) x (Z7 / Z6)

From the above, the relative reduction ratio (V1 / V2) [%] between when the first drive transmission path D1 is used and when the second drive transmission path D2 is used is as follows.
(V1 / V2) = [{(Z2 / Z1) × (Z4 / Z3) × (Z7 / Z6)}
/ (Z4 / Z1) x (Z7 / Z6)] x 100
= (Z2 / Z5) x (Z4 / Z3) x 100

  Therefore, also in the third embodiment in which the resist sheet feeding input gear 11 is used as the second input gear, the relative reduction ratio is the same as the first embodiment, the number of teeth Z3 of the first input gear 7 in the first drive transmission path D1. And the number of teeth Z4 of the first output gear 6a of the first drive transmission path D1, the number of teeth Z2 of the resist paper feed input gear 11 of the second drive transmission path D2, and the second output of the second drive transmission path D2 It is determined by the ratio to the number of teeth Z5 of the gear 6b. Therefore, as in the first embodiment, the relative speed ratio can be made 1% or less when the number of teeth of each drive transmission path is 100 or less.

Example 4
FIG. 7 is a schematic configuration view of a drive device 60C according to a fourth embodiment, where (a) is a schematic cross-sectional view, and (b) is a view as seen from the bracket 8 side.
The fourth embodiment is a modification of the first embodiment, and generally, the life of the electromagnetic clutch is shorter than that of a drive transmission member such as a gear or a pulley, and the electromagnetic clutch (first electromagnetic clutch) needs replacement periodically. 5, the exchangeability of the registration electromagnetic clutch 12, the sheet feeding electromagnetic clutch 15) is enhanced.

  In the fourth embodiment, in order to enhance the exchangeability of the electromagnetic clutches 5, 12, 15, the drive clutches provided coaxially with the electromagnetic clutches 5, 12, 15 are the most outside of the device. When arranged from the bracket side, the electromagnetic clutches 5, 12 and 15 do not overlap the drive transmission member. Specifically, the first input gear 7, the one-way clutch 4 (the second input gear 3), and the registration sheet feeding input gear 11 provided on the rotary shaft X to which the first electromagnetic clutch 5 is attached It was placed on the roller side (inside of the device) than 5. Further, the resist gear 13 disposed coaxially with the resist electromagnetic clutch 12 provided on the resist axis Y was disposed closer to the roller (inside of the apparatus) than the resist electromagnetic clutch 12. Further, the sheet feeding gear 16 coaxially disposed with the sheet feeding electromagnetic clutch 15 provided with the axis Z of the feed roller 27 a is disposed closer to the roller (inside of the apparatus) than the sheet feeding electromagnetic clutch 15.

  Further, in the fourth embodiment, the diameters of the bearings 8b, 8c, 8d attached to the brackets 8 receiving the axes X, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are the electromagnetic clutch 5, 5, It is more than the outer diameter of 12,15. The bearings 8b, 8c, 8d are fixed to the bracket 8 by screws 181b, 181c, 181d.

FIG. 8 is a schematic configuration view of a drive device 60C of the fourth embodiment in which the bearings 8b, 8c and 8d are removed from the bracket 8, (a) is a schematic cross section, and (b) is from the bracket side. It is the schematic seen.
As shown in FIG. 8, when the bearing 8b receiving the rotation axis X is removed from the bracket 8, the bearing 8b is attached to the rotation axis X, and the first input gear 7, one-way clutch 4 (second input gear 3), resist feed input gear The first electromagnetic clutch 5 disposed outside the apparatus (bracket side) than 11 is exposed. From this, without removing the first input gear 7, the one-way clutch 4 (the second input gear 3), and the resist sheet feeding input gear 11 from the rotation axis X, the first electromagnetic clutch is inserted from the hole 81b of the bracket 8 into which the bearing 8b fits. You can access 5

  Further, the inner diameter of the hole 81 b of the bracket 8 in which the bearing 8 b is fitted is larger than the outer diameter of the first electromagnetic clutch 5. Therefore, the first electromagnetic clutch 5 can be removed from the rotation axis X from the hole 81 b, and a new first electromagnetic clutch 5 can be attached to the rotation axis X from the hole 81 b. Thereby, the first electromagnetic clutch 5 can be easily replaced.

  In addition, when the bearing 8c receiving the resist axis Y is removed from the bracket 8, the resist electromagnetic clutch 12 attached to the resist axis Y and disposed on the outer side (bracket side) of the device than the resist gear 13 is exposed. Thus, the resist electromagnetic clutch 12 can be accessed from the hole 81 c of the bracket 8 in which the bearing 8 c is fitted without removing the resist gear 13 from the resist axis Y.

  Further, the inner diameter of the hole 81 c of the bracket 8 in which the bearing 8 c is fitted is larger than the outer diameter of the resist electromagnetic clutch 12. Therefore, the resist electromagnetic clutch 12 can be removed from the resist axis Y from the hole 81c, and a new resist electromagnetic clutch 12 can be attached to the resist axis Y from the hole 81c. Thus, the resist electromagnetic clutch 12 can be easily replaced.

  Further, when the bearing 8d for receiving the axis Z of the feed roller 27a is removed from the bracket 8, the sheet feeding electromagnetic clutch 15 attached to the axis Z and disposed on the outer side (bracket side) of the apparatus than the sheet feeding gear 16 is exposed. Do. Thus, the sheet feeding electromagnetic clutch 15 can be accessed from the hole 81 d of the bracket 8 in which the bearing 8 d is fitted without removing the sheet feeding gear 16 from the axis Z of the feed roller 27 a.

  The inner diameter of the hole 81 d of the bracket 8 in which the bearing 8 d is fitted is larger than the outer diameter of the sheet feeding electromagnetic clutch 15. Therefore, the sheet feeding electromagnetic clutch 15 can be removed from the axis Z of the feed roller 27a from the hole 81d, and a new sheet feeding electromagnetic clutch 15 can be attached to the axis Z from the hole 81d. Thus, the sheet feeding electromagnetic clutch 15 can be easily replaced.

[Example 5]
FIG. 9 is a schematic configuration view of a drive device 60D according to a fifth embodiment, wherein (a) is a schematic cross-sectional view, and (b) is a view as seen from the bracket side.
The fifth embodiment is a modification of the third embodiment, and in the drive device 60B of the third embodiment, the exchangeability of each of the electromagnetic clutches 5, 12, 15 is enhanced.

  In the fifth embodiment, unlike the third embodiment, the first output gear 6a of the first drive transmission path D1 is engaged with the registration sheet input gear 11, and the registration sheet input gear 11 is used as the first input gear. ing. Further, the first electromagnetic clutch 5 is provided on the output rotation axis X2, and engaged with the first output gear 6a in the axial direction. In addition, the drive output member 6 is configured by the second output gear 6b of the second drive transmission path D2 and the output gear 6c. Then, the first electromagnetic clutch 5 is disposed on the outer side (bracket side) of the device than the drive output member 6 and the first output gear 6a provided on the output rotary shaft X2, and viewed from the bracket side, the first electromagnetic The clutch 5 was prevented from overlapping with the drive transmission member.

  Also in the fifth embodiment, similarly to the fourth embodiment, the diameters of the bearings 8e, 8c, 8d attached to the brackets 8 receiving the axes X2, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are set. The outer diameter of each of the electromagnetic clutches 5, 12 and 15 is equal to or greater than that of the other.

FIG. 10 is a schematic configuration view of a drive device 60D of the fifth embodiment in which the bearings 8e, 8c, 8d are removed from the bracket 8, (a) is a schematic cross section, and (b) is from the bracket side. It is the schematic seen.
Also in the fifth embodiment, as in the fourth embodiment, the bearings 8e, 8c, 8d for receiving the axes X2, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are removed from the bracket 8 to obtain each electromagnetic The clutches 5, 12 and 15 are exposed. The electromagnetic clutches 5, 12, 15 can be replaced from the holes 81e, 81c, 81d of the bracket 8 in which the bearings 8e, 8c, 8d are fitted.

[Example 6]
FIG. 11 is a schematic configuration view of a drive device 60E according to a sixth embodiment, where (a) is a schematic cross-sectional view, and (b) is a view as seen from the bracket 8 side.
In the driving device 60E of the sixth embodiment, the motor 1 is provided on the surface of the inside of the apparatus facing the fixing roller 230a of the side plate 9, the first registration roller 29a, and the like. Further, the internal gear 18 is provided, and the drive power is transmitted from the internal gear 18 to the first drive transmission mechanism 61 and the second drive transmission mechanism 62.

  The internal gear 18 has a tubular shape with the bracket side closed, and is rotatably supported by a third fixed shaft S3 to which the side plate 9 and the bracket 8 are fixed. An inner tooth 18 a is formed on the inner peripheral surface of the inner tooth gear 18, and the motor gear 1 a meshes with the inner tooth 18 a. In addition, an external tooth 18b is formed on the outer peripheral surface of the internal gear 18, and the first external gear 2a of the fixing idler gear 2 and the resist feeding input gear 11 are engaged with the external tooth 18b. .

  In the driving device 60E of the sixth embodiment, the motor 1 is provided on the inner side of the apparatus facing the fixing roller 230a of the side plate 9, the first registration roller 29a, and the like, and the first drive transmission mechanism 61 and the second drive transmission are provided. It is disposed on the inner side of the device than the mechanism 62. As a result, the sound of the motor 1 can be blocked by the side plate 9 and the bracket 8, etc., and the sound of the motor 1 can be suppressed from leaking out of the apparatus, and the apparatus can be made quiet.

  Further, by meshing the motor gear 1a with the internal teeth 18a of the internal gear 18, the meshing ratio with the motor gear 1a is improved, and vibration and noise can be suppressed. Further, the meshing portion with the motor gear 1 a can be covered by the internal gear 18, and the meshing noise can be shielded by the internal gear 18. Further, since the bracket side of the internal gear 18 is closed, it is possible to suppress the meshing noise from leaking out. Thereby, noise reduction of the device can be achieved.

  Also in the sixth embodiment, the electromagnetic clutches 5, 12, 15 are disposed on the axially outer side (bracket side), and the axes X, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are received. The diameters of the bearings 8 b, 8 c, 8 d are made equal to or larger than the outer diameters of the electromagnetic clutches 5, 12, 15.

FIG. 12 is a schematic configuration view of a drive device 60E of the sixth embodiment in which the bearings 8b, 8c and 8d are removed from the bracket 8, (a) is a schematic cross section, and (b) is from the bracket side. It is the schematic seen.
Also in the sixth embodiment, the bearings 8b, 8c, 8d for receiving the axes X, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are removed from the bracket 8 to obtain the electromagnetic clutches 5, 12, 15 Is exposed. The electromagnetic clutches 5, 12, 15 can be replaced from the holes 81e, 81c, 81d of the bracket 8 in which the bearings 8b, 8c, 8d are fitted.

  In the sixth embodiment, by providing the motor 1 on the side plate 9, the motor 1 does not disturb the electromagnetic clutches 5, 12 and 15 as compared to the case where the motor 8 is provided on the bracket 8, and the replacement operation is performed. Can be enhanced.

[Example 7]
FIG. 13 is a schematic cross-sectional view of a drive device 60F according to a seventh embodiment.
In the seventh embodiment, the first drive transmission path D1 of the speed switching mechanism D is configured by a gear train composed of a plurality of external gears, and drive transmission is performed using the belt member for the second drive transmission path D2. It is what was constructed.

  The first drive transmission path D <b> 1 includes the first input gear 7, the first idler gear 19, the first output gear 6 a, and the first electromagnetic clutch 5. The second drive transmission path D2 is configured of a second input pulley 3a, a second output pulley 61b, a second timing belt 73 which is a toothed belt, and the one-way clutch 4.

  The first idler gear 19 has a first gear portion 19a meshing with the first input gear 7 and a second gear portion 19b meshing with the first output gear 6a. The first idler gear 19 is fixed to the side plate 9 and the bracket 8 It is rotatably supported by the three fixed shafts S3. The first output gear 6 a, the second output pulley 61 b and the output gear 6 c are formed in the drive output member 6.

  Further, in the seventh embodiment, the second drive transmission path D2 configured using the timing belt is used in the plain paper mode (conveyance mode other than thick paper) where the conveyance speed (rotation speed of the motor 1) is high. The drive transmission path D1 is used in the thick paper mode (thick paper conveyance mode). In the case of the plain paper mode in which the number of rotations of the motor 1 is high, the acceleration is rapid at the start of driving, and the load fluctuation at the start of driving is large. In the case of the plain paper mode, when the first drive transmission path D1 constituted only by the external gear is used, the teeth may collide with each other due to the load fluctuation at the start of driving, and noise may be generated. On the other hand, in the case of the plain paper mode, by using the second drive transmission path D2 configured using the timing belt, the timing belt can be elastically deformed to absorb load fluctuation at the start of driving. This can suppress the generation of noise and the like.

  Further, by configuring the first drive transmission path D1 using only the external gear, it is more resistant to wear and the like than configuring using the timing belt, and durability to repeated use is high. Therefore, by configuring the first drive transmission path D1 used in the thick paper mode in which the conveyance speed (the number of rotations of the motor 1) is low and the load fluctuation at the start of driving is small, only the external gear is used. Can be enhanced. Thus, in Example 7, coexistence of durability and suppression of a noise can be aimed at.

  The driving device according to the first to seventh embodiments not only drives the fixing roller 230a, the first registration roller 29a, and the feed roller 27a, which are conveyance members for conveying the sheet 400 of the image forming apparatus 100, It can also be used to drive a rotating body used for image formation such as a photosensitive member, a primary transfer roller, and an intermediate transfer belt 48. In addition, the driving device according to any one of the first to seventh embodiments may be used to drive the conveying member for conveying the original 410 of the automatic document feeder (ADF: 310) shown in FIG.

The above-described one is an example, and the following effects can be obtained.
(Aspect 1)
Of the two drive transmission paths for transmitting the driving force of the driving source such as the motor 1 to the output target rotating body having different reduction ratios from each other, the image forming apparatus is provided in the first drive transmission path D1 having a small reduction ratio. A drive transmission switching means such as a first electromagnetic clutch 5 is provided which is selectively switched between a state for transmitting the driving force of the drive source and a state for shutting off by a control means such as the control unit 100. In a speed switching device such as the speed switching mechanism D in which the one-way clutch 4 is provided in the two drive transmission path D2, a first final drive transmission such as the first output gear 6a to which the driving force is finally transmitted in the first drive transmission path D1. The first drive transmission member such as the first input gear 7 for transmitting the drive force to the member, and the drive power is transmitted to the end of the second drive transmission path D2 in the same manner as the first final drive transmission member. A second drive transmission member for transmitting driving force to the second final drive transmission member, such as a second output gear 6b arranged above and coaxially.
According to this, the first drive transmission member such as the first input gear 7 for transmitting the driving force to the first final drive transmission member such as the first output gear 6a of the first drive transmission path D1, and the second drive transmission path The second drive transmission member such as the second input gear 3 for transmitting the driving force to the second final drive transmission member such as the second output gear 6b of D2 is provided coaxially with each other. As compared with the above, the downsizing of the speed switching device such as the speed switching mechanism D can be achieved.

(Aspect 2)
In the first aspect, an input drive in which a driving force is input to the first drive transmission path of the first drive transmission member such as the first input gear 7 and the second drive transmission member such as the second input gear 3 respectively. It is a transmission member.
According to this, as described in the first embodiment, each drive transmission path can be configured by two drive transmission members, and the relative speed ratio can be 1% or less with the minimum number of drive transmission members. Thereby, the cost increase due to the increase in the number of parts can be suppressed.

(Aspect 3)
In the aspect 1 or 2, the first drive transmission path D1 and the second drive transmission path D2 are gear drive transmission paths that perform drive transmission by meshing of gears.
According to this, as described in the first embodiment, the speed transmission ratio between one drive transmission path and the other drive transmission path can be reduced to 1% or less with 100 or less teeth of each gear. The increase in diameter of the gear can be suppressed, and the increase in size of the device can be suppressed.
Further, the durability can be enhanced as compared with the case where the first drive transmission path D1 and the second drive transmission path D2 are configured to perform drive transmission using a belt.

(Aspect 4)
In the aspect 1 or 2, the first drive transmission path D1 and the second drive transmission path D2 are belt drive transmission paths that perform drive transmission using a belt.
According to this, as described in the second embodiment, the gear drive transmission path and the belt drive transmission with the number of gear drive transmission path and gear teeth and the number of pulley teeth of the belt drive transmission path being 100 or less. The reduction ratio with the path can be made 1% or less, the diameter increase of the gear and the pulley can be suppressed, and the increase in size of the device can be suppressed.
Further, in the case where the output target rotating body such as the first registration roller 29a is disposed at a position away from the driving source such as the motor 1, the respective drive transmission paths are constituted by gear trains in which a plurality of gears are engaged. Therefore, the number of parts can be reduced and drive transmission can be performed to the output target rotating body, and an increase in cost of the apparatus can be suppressed.

(Aspect 5)
In any one of the modes 1 to 4, the drive transmission switching means such as the first electromagnetic clutch 5 and the one-way clutch 4 are provided coaxially.
According to this, as described in the first embodiment, the number of parts such as bearings is reduced compared to the case where the drive transmission switching means such as the first electromagnetic clutch 5 and the one-way clutch 4 are provided on different shafts. The cost of the apparatus can be suppressed.

(Aspect 6)
In the fifth aspect, the drive transmission switching means such as the first electromagnetic clutch 5 and the one-way clutch 4 are coaxial with the first drive transmission member such as the first input gear 7 and the second drive transmission member such as the second input gear 3. The first drive transmission member is configured to transmit the driving force via the drive transmission switching means, and the second drive transmission member is configured to transmit the driving force via the one-way clutch, and the first output gear is disposed. The first final drive transmission member such as 6a and the second final drive transmission member such as the second output gear 6b are integrally formed products, and from the first final drive transmission member or the second final drive transmission member, such as the resist gear 13 The driving force is output to the output target rotating body.
According to this, as described in the first embodiment, the first final drive transmission member such as the first output gear 6a and the second final drive transmission member such as the second output gear 6b are separately provided. In comparison, the number of parts can be reduced and the number of assembling steps can be reduced. In addition, the number of parts is reduced compared with the case where a drive transmission member such as a gear for outputting a driving force to an output target rotary body such as a resist gear 13 is provided separately from the first final drive transmission member and the second final drive transmission member. can do.

(Aspect 7)
In any one of the aspects 1 to 6, the relative reduction ratio between the first drive transmission path and the second drive transmission path is 1% or less.
According to this, as described in the embodiment, the speed of the output target rotating body can be finely adjusted.

(Aspect 8)
In any one of the aspects 1 to 7, the drive transmission switching means is an electromagnetic clutch.
According to this, it is possible to selectively switch between the state of transmitting the driving force and the state of blocking the transmission of the driving force by performing ON / OFF control of the electromagnetic clutch by control means such as a control unit of the printer.

(Aspect 9)
In any one of the aspects 1 to 8, when viewed from one side in the axial direction such as the bracket side, the drive transmission switching means such as the first electromagnetic clutch 5 is also heavy with any of the plurality of drive transmission members constituting each drive transmission path. I arranged so as not to.
According to this, as described in the fourth embodiment, the drive transmission switching means such as the first electromagnetic clutch 5 can be accessed without removing the member for transmitting the driving force of the drive source. Exchange can be done.

(Aspect 10)
In the ninth aspect, a bearing such as a bearing 8b which is provided on one side in the axial direction such as the bracket side than the drive transmission switching means such as the first electromagnetic clutch 5 and receives the shaft such as the rotation axis X to which the drive transmission switching means is attached. The diameter of the member is larger than the outer diameter of the drive transmission switching means, and the shaft is supported via a bearing member via a bearing member such that it is detachably provided to a side plate such as a bracket 8 that supports the shaft. Provided to the side plates of the bracket 8 etc.
According to this, as described in the fourth embodiment, by removing the bearing member such as the bearing 8b, the drive transmission switching means can be accessed from the hole into which the bearing member provided on the side plate such as the bracket 8 is fitted. The drive transmission switching means can be replaced. Thus, the drive transmission switching means can be easily replaced as compared with the case where the drive transmission switching means is replaced by removing the side plate such as the bracket 8 or the like.

(Aspect 11)
In a driving device including a driving source such as a motor 1 and a driving transmission unit transmitting a driving force of the driving source to a rotating body (in the present embodiment, the fixing roller 230a, the first registration roller 29a, and the feed roller 27a). The drive transmission unit includes the speed switching device according to any one of aspects 1 to 9.
According to this, it is possible to switch the rotational speed of the rotating body without changing the rotational speed of the drive source.

(Aspect 12)
In aspect 11, the driving force of the driving source such as the motor 1 is transmitted to the plurality of rotating bodies (in the present embodiment, the fixing roller 230a, the first registration roller 29a, and the feed roller 27a).
According to this, when the rotational speed of the plurality of rotating members (in the present embodiment, the fixing roller 230a) is changed by the number of rotations of the driving source such as the motor 1, the drive transmission path of the speed switching device is switched. The rotational speed of another rotating body (in the present embodiment, the first registration roller 29a and the feed roller 27a) can be set to a desired rotational speed.

(Aspect 13)
In the twelfth aspect, a plurality of first drive transmission units such as a first drive transmission mechanism 61 that transmits driving force to forward and reverse rotating bodies such as the fixing roller 230a that rotates one direction of the plurality of rotating bodies. A second drive such as a second drive transmission mechanism 62 for transmitting a driving force to a one-way rotator (in the present embodiment, the first registration roller 29a and the feed roller 27a) which rotates only in one direction among the rotators. The second drive transmission unit is provided with a speed switching device such as the speed switching mechanism D.
According to this, as described in the first embodiment, the drive source such as the motor 1 can be reversely rotated, and the forward / reverse rotation body such as the fixing roller 230a can be reversely rotated. On the other hand, when the drive transmission switching means such as the first electromagnetic clutch 5 is in a state of interrupting the drive transmission, when the drive source is reversely rotated, the one-direction rotating body (in the present embodiment, the first registration roller 29a, The driving force is not transmitted to the feed roller 27a), and the one-direction rotating body does not rotate in the opposite direction to one direction.

(Aspect 14)
In the thirteenth aspect, the forward and reverse rotation body is the fixing roller 230a, and the one-way rotation body is the registration roller.
According to this, as described in the first embodiment, when a jam of a small size sheet occurs in the fixing nip portion, the fixing roller 230 a is reversely rotated to allow the rear end of the sheet 400 from the fixing device 20 to be rotated. The sheet 400 can be exposed and easily taken out.

(Aspect 15)
In Aspect 13 or 14, a first drive mode, which is a plain paper transport mode for transporting plain paper to rotate a drive source such as the motor 1 at a first rotational speed, and the drive source at a first rotational speed And the second drive mode, which is a thick paper conveyance mode for conveying thick paper rotated at a low rotational speed, and switches the speed of the speed switching device at the time of switching the drive mode.
According to this, as described in the embodiment, the rotating member such as the fixing roller 230a to which the driving force is transmitted by the first drive transmission unit such as the first drive transmission mechanism 61, and the second drive transmission mechanism 62 The relative speed ratio with the rotating body such as the first registration roller 29a to which the driving force is transmitted by the driving transmission unit is set to the first driving mode which is the plain paper conveyance mode and the second driving mode which is the thick paper conveyance mode. It can be different from time to time.

(Aspect 16)
In any one of the aspects 10 to 15, the internal gear such as the internal gear 18 meshing with the output gear portion such as the motor gear 1a provided on the output shaft of the drive source such as the motor 1 is provided.
According to this, as described in the sixth embodiment, the meshing ratio with the output gear portion such as the motor gear 1a can be improved, and vibration and noise can be suppressed. Further, the meshing portion with the output gear portion can be covered with the internal gear such as the internal gear 18, meshing noise can be shielded by the internal gear, and noise can be suppressed.

(Aspect 17)
In any one of the tenth to sixteenth aspects, the drive source such as the motor 1 is provided on the rotary body side which is the inner side of the image forming apparatus 100 in the axial direction than the drive transmission unit.
According to this, as described in the sixth embodiment, the noise of the drive source leaks to the outside of the image forming apparatus 100 as compared with the case where it is provided on the opposite side to the rotating body side which is the outer side of the image forming apparatus 100. Therefore, the image forming apparatus 100 can be made quiet.

(Aspect 18)
Of the two drive transmission paths for driving the driving source such as motor 1 and the reduction ratio different from each other and transmitting the driving force of the driving source to the output target rotating body, the first drive transmission path D1 having the smaller reduction ratio. A drive transmission switching unit such as a first electromagnetic clutch 5 is selectively controlled to selectively switch between a state transmitting the driving force of the driving source and a state blocking the driving force by a control unit such as a control unit of the image forming apparatus 100. In the drive device 60F including the speed switching device such as the speed switching mechanism D in which the one-way clutch 4 is provided in the second drive transmission path having a large ratio, any one of the first drive transmission path D1 and the second drive transmission path D2 One is a gear drive transmission path for performing drive transmission by engagement of gears, and the other is a belt drive transmission path for performing drive transmission using a belt, and the drive source There is a first drive mode such as a plain paper transport mode of rotating at a first rotational speed, and a second drive mode of a thick sheet transport mode of rotating the drive source at a rotational speed slower than the first rotational speed. And the control means transmits the driving force to the output target rotating body via the belt drive transmission path in the first drive mode, and transmits the gear drive transmission path in the second drive mode. The drive transmission switching means is controlled so that the driving force is transmitted to the output target rotor via the same.
According to this, as described in the seventh embodiment, the belt drive transmission path is used in the first drive mode, in which the acceleration is accelerated at the start of the drive and the load fluctuation is larger than the second drive mode. Load fluctuation at the start of driving can be absorbed by elastic deformation of the belt. As a result, the generation of noise can be suppressed as compared to the case of using a gear drive transmission path that performs drive transmission by meshing of gears. On the other hand, in the second drive mode in which the load fluctuation at the start of driving is smaller than the first mode, it is possible to use a gear drive transmission path having higher durability than the belt drive transmission path. This makes it possible to achieve both quietness of the device and durability.

(Aspect 19)
A sheet conveying apparatus comprising a conveying member (in the present embodiment, a fixing roller 230a, a first registration roller 29a, and a feed roller 27a) for conveying a sheet, and a driving means for rotationally driving the conveying member, the driving means The drive device according to any one of Aspects 11 to 18 was used.
According to this, size reduction of an apparatus can be achieved by using the drive device of the aspects 11-17. Further, by using the driving device of aspect 18, noise reduction of the sheet conveying device can be achieved.

(Aspect 20)
In an image forming apparatus including an image forming unit for forming an image and a driving unit for driving a rotating body, the driving device according to any one of Aspects 11 to 18 is used as a driving unit.
According to this, size reduction of an apparatus can be achieved by using the drive device of the aspects 11-17. Further, by using the drive device of aspect 18, noise reduction of the device can be achieved.

1: Motor 1a: Motor gear 2: Fixing idler gear 2a: First external gear 2b: Second external gear 3: Second input gear 3a: Second input pulley 4: One-way clutch 5: First electromagnetic clutch 5a: Drive claw 5b: Armature 5c: Rotor 5d: Electromagnetic coil 5e: Shaft fixing portion 5f: Drive connection member 6: Drive output member 6a: First output gear 6b: Second output gear 6c: Output gear 7: First input gear 7a Drive connection hole 8: Brackets 8b, 8c, 8d, 8e: Bearing 9: Side plates 9a, 9b, 9c, 9d, 9e: Bearing 10: Fixing gear 11: Registration sheet input gear 12: Registration electromagnetic clutch 13: Registration gear 14 : Paper feed idler gear 15: Paper feed electromagnetic clutch 16: Paper feed gear 18: Internal gear 18 a: Internal gear 18 b: External gear 19: First idler gear 19 a A first gear portion 19b: a second gear portion 20: a fixing device 26: a sheet storage cassette 27: a separation means 27a: a feed roller 27b: a separation pad 28: a pair of conveyance rollers 28a: a first conveyance roller 28b: a second conveyance roller 29 : Registration roller pair 29a: First registration roller 29b: Second registration roller 30: Discharge roller pair 31: Stack unit 32: Toner bottle 33: Bottle holder 41: Photoreceptor 46: Imaging unit 47: Optical writing unit 48: intermediate transfer belt 49: primary transfer bias roller 50: belt cleaning device 52: secondary transfer backup roller 53: cleaning backup roller 54: tension roller 55: intermediate transfer unit 59: secondary transfer roller 60: drive device 61: first Drive transmission mechanism 61a: first output pulley 6 1b: second output pulley 62: second drive transmission mechanism 71: first input pulley 72: first timing belt 73: second timing belt 81b, 8c, 81d, 81e: bracket hole 200 in which the bearing is fitted 200: device body 210 A sheet feeding device 230: a fixing roller pair 230a: a fixing roller 230b: a pressure roller 300: an image reading device 310: an automatic document feeder 311: a document placing table 320: a scanner unit 321: a fixed reading unit 322: a moving reading unit 323: Image reading sensor 330: Document conveyance path 400: Sheet 410: Document D: Speed switching mechanism D1: First drive transmission path D2: Second drive transmission path S1: First fixed axis S2: Second fixed axis S3: Third fixed Axis T: Fixing axis U: Output fixed axis X: Rotation axis X2: Output rotation axis Y: Resist axis Z: Feed roller axis

JP 2012-203010 A

Claims (20)

Of the two drive transmission paths for transmitting the driving force of the driving source to the output target rotating body having different reduction ratios, a state in which the driving force is transmitted by the control means to the first driving transmission path having a small reduction ratio. In a speed switching device provided with a drive transmission switching means which is selectively controlled to be switched to a shutoff state, and provided with a one-way clutch in a second drive transmission path having a large reduction ratio,
A first drive transmission member for transmitting the drive force to a first final drive transmission member to which the drive force is finally transmitted in the first drive transmission path, and the drive force is finally transmitted in the second drive transmission path And a second drive transmission member for transmitting the driving force to a second final drive transmission member coaxially arranged with the first final drive transmission member, provided coaxially with the second drive transmission member. . In the speed switching device according to claim 1,
The speed switching device according to claim 1, wherein the first drive transmitting member and the second drive transmitting member are input drive transmitting members to which the driving force is first transmitted in each drive transmitting path. In the speed switching device according to claim 1 or 2,
The speed switching device according to claim 1, wherein the first drive transmission path and the second drive transmission path are gear drive transmission paths that perform drive transmission by meshing of gears. In the speed switching device according to claim 1 or 2,
The speed switching device according to claim 1, wherein the first drive transmission path and the second drive transmission path are belt drive transmission paths that perform drive transmission using a belt. The speed switching device according to any one of claims 1 to 4.
A speed switching device characterized in that the drive transmission switching means and the one-way clutch are coaxially provided. In the speed switching device according to claim 5,
The drive transmission switching means and the one-way clutch are disposed coaxially with the first drive transmission member and the second drive transmission member, and the first drive transmission member is driven via the drive transmission switching means. Power is transmitted, and the second drive transmission member is configured to transmit the driving force via the one-way clutch,
The first final drive transmission member and the second final drive transmission member are integrally formed products,
The speed switching device, wherein the driving force is output from the first final drive transmission member or the second final drive transmission member to the output target rotary body. The speed switching device according to any one of claims 1 to 6.
The relative speed reduction ratio between the first drive transmission path and the second drive transmission path is 1% or less. The speed switching device according to any one of claims 1 to 7.
The speed switching device, wherein the drive transmission switching means is an electromagnetic clutch. The speed switching device according to any one of claims 1 to 8.
When viewed from one side in the axial direction, the drive transmission switching means is disposed so as not to overlap any one of a plurality of drive transmission members constituting each drive transmission path. In the speed switching device according to claim 9,
The diameter of the bearing member provided on the one side in the axial direction with respect to the drive transmission switching means and receiving the shaft to which the drive transmission switching means is attached is larger than the outer diameter of the drive transmission switching means, and A speed switching device characterized by being detachably provided to a side plate supporting the shaft via the bearing member. Driving source,
And a drive transmission unit for transmitting the drive force of the drive source to the rotating body.
A drive device comprising the speed switching device according to any one of claims 1 to 10, wherein the drive transmission unit. In the drive device according to claim 11,
A driving device for transmitting the driving force to a plurality of rotating bodies. In the drive device according to claim 12,
A first drive transmission unit for transmitting the driving force to forward and reverse rotating bodies, which is one of a plurality of rotating bodies, and a one-way rotating body, which rotates only in one direction, which is one of a plurality of rotating bodies A second drive transmission unit for transmitting the driving force to the
A driving device characterized in that the speed switching device is provided in a second drive transmission unit. In the drive device according to claim 13,
A driving device characterized in that the forward and reverse rotating body is a fixing roller, and the one-way rotating body is a registration roller. In the drive device according to claim 13 or 14,
A first drive mode in which the drive source is rotated at a first rotational speed;
And a second drive mode in which the drive source is rotated at a rotational speed slower than the first rotational speed.
A driving device characterized in that switching of the speed of the speed switching device is performed when switching the driving mode. In the drive device according to any one of claims 11 to 15,
A driving device comprising an internal gear engaged with an output gear portion provided on an output shaft of the driving source. In the drive device according to any one of claims 11 to 16,
The drive device, wherein the drive source is provided closer to the rotary body than the drive transmission unit in the axial direction. Driving source,
A state in which the driving force is transmitted by the control means to a first drive transmission path having a small reduction ratio among the two drive transmission paths having different reduction ratios and transmitting the driving force of the drive source to the output target rotating body And a speed switching device provided with a drive transmission switching means which selectively switches between a state where it is shut off and a state where it is shut off, and a one-way clutch is provided in a second drive transmission path having a large speed reduction ratio,
One of the first drive transmission path and the second drive transmission path is a gear drive transmission path for performing drive transmission by meshing of gears, and the other is a belt drive transmission path for performing drive transmission using a belt,
A first drive mode in which the drive source is rotated at a first rotational speed;
And a second drive mode in which the drive source is rotated at a rotational speed slower than the first rotational speed.
The control means transmits the driving force to the output target rotor via the belt drive transmission path when in the first drive mode, and passes through the gear drive transmission path when in the second drive mode. And controlling the drive transmission switching unit so that the driving force is transmitted to the output target rotating body. A sheet conveying apparatus comprising: a conveying member for conveying a sheet; and driving means for rotationally driving the conveying member.
A sheet conveying apparatus using the driving device according to any one of claims 10 to 18 as the driving means. Image forming means for forming an image;
An image forming apparatus comprising a drive unit for driving a rotating body;
An image forming apparatus using the drive device according to any one of claims 10 to 18 as the drive means.

Images