JP6860852B2 - Speed switching device, drive device, sheet transfer device and image forming device - Google Patents

Description

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

Of the two drive transmission paths that have different reduction ratios and transmit the drive force of the drive source to the output target rotating body side, the drive force of the drive source is transmitted by the control means to the first drive transmission path having the smaller reduction ratio. A speed switching device is known in which an electromagnetic clutch as a drive transmission switching means for selectively switching and controlling a state and a shutoff state is provided, and a one-way clutch is provided in a second drive transmission path having a large reduction ratio.

Patent Document 1 describes, as the speed switching device, a first drive transmission member for transmitting a 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, the first final drive transmission member and the second final drive transmission member arranged coaxially with the first final drive transmission member are provided with different shafts from each other. ing.

However, in the above-mentioned Patent Document 1, there is a possibility that the speed switching device becomes large.

In order to solve the above problems, the present invention uses the first drive transmission path having a smaller reduction ratio among the two drive transmission paths in which the reduction ratios are different from each other and the driving force of the drive source is transmitted to the output target rotating body. In a speed switching device in which a drive transmission switching means for selectively switching and controlling a state in which the driving force is transmitted and a state in which the driving force is cut off is provided by the control means, and a one-way clutch is provided in the second drive transmission path having a large reduction ratio. The first drive transmission member that transmits the driving force to the first final drive transmission member to which the driving force is finally transmitted in the first drive transmission path, and the driving force that is finally transmitted in the second drive transmission path. is transmitted, and a second drive transmission member for transmitting the driving force to the second final drive transmission member disposed on the first final drive transmission member coaxially, only set coaxially, viewed from one side in the axial direction At that time, the drive transmission switching means is arranged so as not to overlap any of the plurality of drive transmission members constituting each drive transmission path .

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

The schematic block diagram which shows one structural example of the image forming apparatus which concerns on embodiment of this invention. The schematic sectional view of the drive device which concerns on Example 1. FIG. Schematic block diagram of the first electromagnetic clutch. A control flow diagram showing an example of control of a drive device. FIG. 3 is a schematic cross-sectional view of the drive device according to the second embodiment. FIG. 3 is a schematic cross-sectional view of the drive device according to the third embodiment. The schematic block diagram of the drive device which concerns on Example 4. FIG. FIG. 6 is a schematic configuration diagram of a drive device according to a fourth embodiment in which each bearing is removed from a bracket. The schematic block diagram of the drive device which concerns on Example 5. FIG. The schematic block diagram of the drive device of Example 5 which removed each bearing from a bracket. The schematic block diagram of the drive device which concerns on Example 6. FIG. 6 is a schematic configuration diagram of a drive device according to a sixth embodiment in which each bearing is removed from a bracket. FIG. 6 is a schematic cross-sectional view of the drive device according to the seventh embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a configuration example 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. In this embodiment, the electrophotographic image forming apparatus 100 will be described, but the image forming method in the image forming apparatus 100 may be another method such as an inkjet method.

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

The image reading device 300 includes an automatic document feeding device (ADF: Auto Document Feeder) 310 as a sheet transporting device, and a scanner unit 320. The automatic document feeding device 310 feeds out the document 410, which is a sheet set by the user as an image scanning target, and the scanner unit 320 reads the image of the document 410 sent out from the automatic document feeding device 310.

The thickness of the sheet such as the paper 400 or the original 410 to be conveyed 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.

The apparatus main body (printing unit) 200 has four image forming units 46Y, M, C, and K for forming a toner image of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). It has. These use Y, M, C, and K toners of different colors as the image forming substance, but have the same configuration other than that, and are replaced at the end of the service life. Each of the image forming units 46Y, M, C, and K includes a drum-shaped photoconductor as a latent image carrier, a drum cleaning device as a photoconductor cleaning means, a static elimination device, a charging device, a developing device, and the like. These image-drawing units can be attached to and detached from the apparatus main body 200, and consumable parts can be replaced at once.

In FIG. 1, an optical writing unit 47 is arranged at the lower part of the image forming units 46Y, M, C, and K in the figure. The optical writing unit 47 as a latent image forming means irradiates and exposes the respective photoconductors in the image forming units 46Y, M, C, and K with the laser light L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on each photoconductor. The optical writing unit 47 is exposed to light through a plurality of optical lenses and mirrors while deflecting the laser light emitted from the light source in the main scanning direction (photoreceptor axis direction) by a polygon mirror rotationally driven by a motor. It irradiates the body.

Below the optical writing unit 47, a paper feeding device 210 having a sheet accommodating cassette 26, a separating means 27 incorporated therein, and the like is arranged. The sheet accommodating cassette 26 stores a plurality of sheets of paper 400 in the form of a stack of sheets. Further, the separation means 27 forms a separation nip by a feed roller 27a that can be driven to rotate and a separation pad 27b that abuts on the feed roller 27a.

The feed roller 27a of the separating means 27 is in contact with the top paper 400 in the sheet bundle in the sheet accommodating cassette 26. The feed roller 27a feeds the paper 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 a state of being overlapped with each other, the feed roller 27a comes into contact with only the highest-level paper 400 among those papers. The uppermost paper 400 moves in the feeding direction in the separation nip following the surface movement of the feed roller 27a. On the other hand, the lower papers other than the uppermost paper 400 are provided with a load resistance by the separation pad 27b that does not move on the surface. As a result, the lower paper 400 cannot move in the feeding direction following the uppermost paper 400 and stays in the separation nip. In this way, the separating means 27 separates only the top-level paper 400 from the plurality of sheets 400 sent out from the sheet accommodating cassette 26 into one sheet, and separates the first sheet transport path from the separation nip (). Feeding path) 250.

A transport roller pair 28 as a transport means is arranged near an intermediate point in the length direction of the paper feed path. The transport roller pair 28 forms a transport nip by bringing the first transport roller 28a as a transport member and the second transport roller 28b as a transport member into contact with each other. Of the two transfer rollers, at least the first transfer roller 28a is rotationally driven by the drive means.

Further, a resist roller pair 29 as a butt-conveying means is arranged near the end in the length direction of the paper feed path. The resist roller pair 29 includes a first resist roller 29a as a butt transfer member and a second resist roller 29b that abuts on the resist roller pair 29 to form a resist nip as a butt transfer nip. Of the two resist roller pairs 29, at least the first resist roller 29a is rotationally driven by a drive device which is a drive means described later.

The first transfer roller 28a of the transfer roller pair 28 is started to rotate at about the same time as the rotation drive of the feed roller 27a of the separation means 27 is started, or with a slight time lag. The tip of the paper 400 sent out from the separation nip of the separation means 27 to the paper feed path is eventually sandwiched between the transfer nips of the transfer roller pair 28. Since the first transfer roller 28a is rotationally driven at a rotation speed faster than that of the feed roller 27a, the paper 400 is stretched with a strong tension between the separation nip and the transfer nip at this time. Then, when a strong torque is applied to the feed roller 27a, the torque limiter operates and the feed roller 27a is brought around to the paper 400. At this time, the torque limiter operates irregularly, so that the back tension is irregularly applied to the paper 400. Then, the paper 400 slips on the first transport roller 28a, thereby promoting the wear of the first transport roller 28a.

After that, the paper 400 is fed from the inside of the transfer nip toward the resist roller pair 29 by the rotational drive of the first transfer roller 28a, and then the tip of the paper 400 is abutted against the resist nip of the resist roller pair 29. At this time, since the rotational drive of the resist roller pair 29 is stopped, the paper 400 cannot enter the resist nip and gradually bends. This deflection corrects the skew of the paper 400.

After the paper 400 starts to be fed from the transport nip of the transport roller pair 28, the rotary drive of the feed roller 27a of the separation means 27 and the rotary drive of the transport roller pair 28 are stopped when a predetermined timing arrives. As a result, the paper 400 is temporarily stopped in the state where the tip portion is bent.

An intermediate transfer unit 55 that moves endlessly while tensioning an intermediate transfer belt 48 as an intermediate transfer body is arranged above the image forming units 46Y, M, C, and K in the drawing. The intermediate transfer unit 55 includes an intermediate transfer belt 48, four primary transfer bias rollers 49Y, M, C, K, a belt cleaning device 50, and the like. It also includes a secondary transfer backup roller 52, a cleaning backup roller 53, a tension roller 54, and the like.

The intermediate transfer belt 48 is endlessly moved counterclockwise in the drawing by the rotational drive of at least one of the rollers while being stretched on the three rollers inside the loop. The primary transfer bias rollers 49Y, M, C, and K each form a primary transfer nip by sandwiching the intermediate transfer belt 48 that has been moved endlessly between the photoconductors 41Y, M, C, and K. These are of a method in which a transfer bias having the opposite polarity (for example, plus) to the toner is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 48. All rollers except the primary transfer bias rollers 49Y, M, C, and K are electrically grounded. The intermediate transfer belt 48 sequentially passes through the primary transfer nips for Y, M, C, and K as it moves endlessly, and Y, M, C, on the photoconductors 41Y, M, C, and K, The K toner images are superimposed and primary transferred. As a result, 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 arranged inside the belt loop forms a secondary transfer nip by sandwiching the intermediate transfer belt 48 with the secondary transfer roller 59 arranged outside the belt loop. The four-color toner image formed on the intermediate transfer belt 48 is transferred to the paper 400 by the secondary transfer nip. The transfer residual toner that has not been transferred to the paper 400 adheres to the intermediate transfer belt 48 after passing through the secondary transfer nip. It is cleaned by the belt cleaning device 50.

After the rotational drive of the feed roller 27a and the transfer roller pair 28 is suspended, when the timing at which the paper 400 can be synchronized with the four-color toner image on the intermediate transfer belt 48 in the secondary transfer nip comes, the feed roller 27a and the feed roller 27a The rotary drive of the transfer roller pair 28 is restarted. Further, the rotary drive of the resist roller pair 29 starts. As a result, the paper 400 is sandwiched between the resist nip of the resist roller pair 29 and then fed from the resist nip toward the secondary transfer nip. Then, in the secondary transfer nip, it is superimposed on the four-color toner image on the intermediate transfer belt 48.

The paper 400 sent out from the secondary transfer nip is transferred to the surface by heat and pressure when passing between the fixing roller pair 230 composed of the fixing roller 230a and the pressure roller 230b of the fixing device 20. The four-color toner image is fixed. After that, the paper 400 is discharged to the outside of the machine through the space between the paper ejection rollers and the rollers 30. A stack portion 31 is formed on the upper surface of the apparatus main body 200, and the paper 400 discharged to the outside of the machine by the paper ejection roller pair 30 is sequentially stacked on the stack portion 31.

A bottle container 33 is arranged between the intermediate transfer unit 55 and the stack portion 31 above the intermediate transfer unit 55. The bottle container 33 accommodates the toner bottles 32Y, M, C, and K as a replenishment toner accommodating portion for accommodating Y, M, C, and K toners. The toner bottles 32Y, M, C, and K are installed on the bottle container 33 so as to be placed 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 replenished to the developing devices of the image forming units 46Y, M, C, and K by a toner replenishing device as a toner transfer means described later. Will be done. These toner bottles 32Y, M, C, and K can be attached to and detached from the apparatus main body 200 independently of the image forming units 46Y, M, C, and K.

A switchback device is arranged in the vicinity of the fixing device 20. In the double-sided print mode in which an image is formed on both sides of the paper 400, the paper 400 that has passed through the fixing device 20 after the toner image is formed on only one side is turned upside down by this switchback device. The upside-down paper 400 is retransmitted toward the resist nip of the resist roller vs. 29 via the inversion path 254. Then, after being sent from the resist nip to the secondary transfer nip to form a toner image on the other surface, the fixing device 20 performs a fixing process on the toner image on the other surface, and then the paper ejection roller. It is stacked on the stack unit 31 via pair 30.

An image reading device 300 including an automatic document feeding device (ADF) 310 and a scanner unit 320 is arranged on the apparatus main body (printing unit) 200 as described above. The image reading device 300 is fixed on a gantry 199 supported by two legs fixed to the back surface of the apparatus main body 200, and is between the stack portion 31 of the apparatus main body 200 and the gantry 199. There is a large space in between. The paper 400 stacked on the stack portion 31 will be located in that space.

The scanner unit 320 of the image reading device 300 has a fixed reading unit 321 and a moving reading unit 322. The mobile reading unit 322 is arranged directly under the second contact glass fixed to the upper wall of the casing of the scanner unit 320 so as to come into contact with the document 410, and an optical system including a light source, a reflection mirror, and the like is shown in the drawing. It can be moved in the left-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 on the surface of the document 410 placed on the second contact glass, and then passed through a plurality of reflection mirrors. Then, the light is received by the image reading sensor 323 fixed to the scanner body.

On the other hand, the fixed reading unit 321 has a light source, a reflection mirror, an image reading sensor 323 such as a CCD, and the like, and is made of a first contact glass fixed to the upper wall of the casing of the scanner unit 320 so as to come into contact with the document 410. It is arranged directly below. Then, when the document 410 conveyed by the document automatic feed device 310 passes over the first contact glass, the image reading sensor passes through a plurality of reflection mirrors while sequentially reflecting the light emitted from the light source on the document surface. Receive light with. As a result, the first surface of the document 410 is lightly scanned without moving the optical system including the light source and the reflection mirror. The automatic document feeding device 310 includes a second surface reading sensor that lightly scans the second surface of the document 410.

When a bundle of originals in which a plurality of originals 410 are stacked is set in the automatic document feeder 310, the originals 410 can be automatically conveyed one by one. Then, the images of the documents 410 automatically transported one by one can be sequentially read by the fixed reading unit 321 in the scanner unit 320 and the second-side fixed reading unit in the automatic document feeding device 310. In this case, after setting the document bundle on the document mounting table 311, the copy start button is pressed. Then, the document automatic feeding device 310 conveys the document 410 of the document bundle placed on the document loading table 311 in order from the top. Immediately after the document 410 is inverted in the process of this transfer, the document 410 is passed directly above the fixed reading unit 321 of the scanner unit 320. 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 having the above configuration, the apparatus main body 200 has first to third paper transport paths 250, 252, and 253 as sheet transport paths for transporting the paper 400. In the first paper transport path 250, the paper 400 sent from the paper feed device 210 by the feed roller 27a passes through the transport roller pair 28 and the resist roller pair 29, and the secondary transfer backup roller 52 and the secondary transfer roller 59. Is conveyed to the secondary transfer position facing each other. At the secondary transfer position, the toner image formed on the intermediate transfer belt 48 is transferred to the paper 400. In the second paper transport path 252, the paper 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 for fixing the toner image, and passes through the paper ejection roller pair 30. The paper is discharged onto the stack portion 31. In the third paper transport path 253, the paper 400 that has passed through the nip portion of the fixing roller pair 230 is transported to the reversing path 254 in order to form an image on both sides of the paper 400.

The image reading device 300 has a document transport path 330 as a sheet transport path for transporting the document 410. In the document transport path 330, the document 410 fed from the document automatic feed device 310 is transported to the image reading position of the scanner unit 320.

Next, an example of the drive device included in this 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 drive device 60 according to the first embodiment drives the fixing roller 230a, the first resist roller 29a, and the feed roller 27a.
The motor 1, which is a drive source for driving the fixing roller 230a, the first resist roller 29a, and the feed roller 27a, is fixed to the surface of the bracket 8 opposite to the roller side surface. The motor shaft of the motor 1 penetrates 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 first drive transmission mechanism 61 that transmits the drive to the fixing roller 230a, and the drive transmission to the first resist roller 29a and the feed roller 27a. A second drive transmission mechanism 62 for performing the above is provided.

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 a bracket 8 and a side plate 9, and has a first external tooth gear 2a that meshes with the motor gear 1a and a second external tooth that meshes with the fixing gear 10. It has 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 includes a resist paper feed input gear 11, a speed switching mechanism D as a speed switching device, a resist gear 13, a resist electromagnetic clutch 12, a paper feed idler gear 14, a paper feed gear 16, and a paper feed electromagnetic clutch 15. doing. The resist paper feed input gear 11 is attached to the rotating shaft X so as to rotate integrally with the rotating shaft X rotatably supported by the bracket 8 and the side plate 9 via bearings 8b and 9b.

The speed switching mechanism D has two drive transmission paths having different reduction ratios. The first drive transmission path D1 includes a first input gear 7 which is an input drive transmission member and a first drive transmission member, a first output gear 6a which is a first final drive transmission member, and a first electromagnetic wave which is a drive transmission switching means. It has a clutch 5. The second drive transmission path D2 has a second input gear 3 which is an input drive transmission member and 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 rotating shaft 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 from the axial direction.
The one-way clutch 4 can transmit a driving force between the rotating shaft X and the second input gear 3 when the rotating shaft X rotates in a positive direction relative to the one-way clutch 4, and the rotating shaft X When is rotating in the opposite direction to the one-way clutch 4, it is configured to idle with respect to the rotation axis X.

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

The paper feed idler gear 14 meshes with the resist 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 meshes with the paper feed idler gear 14. The paper feed gear 16 and the paper feed electromagnetic clutch 15 are provided on the shaft Z of the feed roller 27a rotatably supported by the side plate 9 and the bracket 8 via bearings 9d and 8d. The paper feed gear 16 is rotatably supported by the shaft Z of the feed roller 27a, and the paper feed electromagnetic clutch 15 is fixed to the shaft Z so as to rotate integrally with the shaft Z, and is fixed to the shaft Z from the axial direction. It is engaged with the paper 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 shaft X is inserted, and the cross section of the insertion hole is a substantially rounded square shape in which a part of the circular shape is cut out. The rotating shaft X has a substantially rounded quadrangular cross section having a shape similar to that of the insertion hole so as to fit into the insertion hole. The substantially rounded square shape of the rotating shaft X extends to the location where the first electromagnetic clutch 5 is attached. By fitting the substantially rounded square portion of the shaft fixing portion 5e with the substantially rounded square portion of the rotating shaft X, the shaft fixing portion 5e is fixed so as to rotate with the rotating shaft X. ..

An electromagnetic coil portion 5d is rotatably attached to the shaft fixing portion 5e with respect to 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 provided with a pair of drive claws 5a extending toward the second resist output gear side. A pair of drive connecting holes 7a are formed on the surface of the first input gear 7 facing the first electromagnetic clutch 5, and the drive claws 5a of the drive connecting member 5f are fitted into these drive connecting holes 7a. .. As a result, the first electromagnetic clutch 5 and the first input gear 7 can rotate integrally.

When the first electromagnetic clutch 5 is turned off, the drive connecting member 5f is in a free state and can idle with respect to the shaft fixing portion 5e. As a result, the drive transmission from the rotating shaft X to the first input gear 7 is cut off, and the drive connecting member 5f and the first input gear 7 idle with respect to the rotating shaft X.

When the clutch is ON, a current flows through the electromagnetic coil portion 5d and an electromagnetic force is generated. When an electromagnetic force is generated, the armature 5b of the metal disk is attracted to the electromagnetic coil portion 5d by the electromagnetic force, and the drive connecting member 5f integrated with the armature 5b slides to the rotor portion 5c side. Then, the armature 5b is attracted to the rotor portion 5c and transmitted from the rotating shaft X to the power of the first input gear 7 section via the first electromagnetic clutch 5.

The first electromagnetic clutch 5 may be provided with the drive connecting member 5f slidable in the axial direction, and the first input gear 7 may be rotatable with respect to the rotation shaft X. As a result, the gap between the first input gear 7 and the rotating shaft X can be made smaller than in the case where the first input gear 7 is configured to be slidable in the axial direction. As a result, it is possible to prevent the first input gear 7 from tilting with respect to the rotation axis X.

The resist electromagnetic clutch 12 and the paper feed 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 turned on, the second input gear 3 and the one-way clutch 4 rotate faster than the rotating shaft X, and the rotating shaft X rotates in the opposite direction 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. As a result, 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 cut off. Therefore, the driving force is not transmitted from the second output gear 6b to the second input gear 3. Therefore, in this case, the rotation shaft X rotates in a positive direction relative to the one-way clutch 4. As a result, the driving force is transmitted from the rotating shaft X to the second input gear 3, and the driving force is input to the resist gear 13 via the second drive transmission path D2.

In this way, by making the reduction ratio of the second drive transmission path D2 having the one-way clutch 4 larger than the reduction ratio of the first drive transmission path D1, the rotation shaft X is turned ON / OFF of the first electromagnetic clutch 5. The relative movement direction with respect to the one-way clutch 4 can be switched. As a result, the drive transmission state of the one-way clutch 4 can be switched by turning the first electromagnetic clutch 5 ON / OFF.

Table 1 below is a diagram showing an example of specifications of each gear of the speed switching mechanism D of 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. It is 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 rotating shaft X is rotating at 500 [rpm] and the first electromagnetic clutch 5 is ON, the driving force of the rotating shaft X is the first input gear 7 via the first electromagnetic clutch 5. 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, a 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)), which is faster than the rotation axis X (500 [rpm]). As a result, the rotating shaft X rotates relatively in the opposite direction to the one-way clutch 4 that rotates integrally with the second input gear 3, and the one-way clutch 4 runs idle with respect to the rotating shaft X. As a result, the transmission of the driving force from the second input gear 3 to the second output gear 6b is cut off, and the driving force is transmitted to the resist gear 13 via the first drive transmission path D1.

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 rotation speed of the second input gear 3 becomes slower than the rotation axis X. It ends up. As a result, the rotation axis X rotates in a positive direction relative to the one-way clutch 4. Therefore, in this case, the relative rotation direction of the rotation axis X with respect to the one-way clutch 4 cannot be switched between when the electromagnetic clutch is ON and when the electromagnetic clutch is OFF. As a result, even when the first electromagnetic clutch is turned on, the one-way clutch 4 does not idle with respect to the rotating shaft 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, since the reduction ratio of the second drive transmission path D2 is larger than the reduction ratio of the first drive transmission path D1, the rotation axis X with respect to the one-way clutch 4 when the first electromagnetic clutch is ON. The relative rotation direction of can be switched from forward rotation to reverse rotation. As a result, 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 an electromagnetic clutch. Therefore, the device can be made cheaper as compared with the case where an electromagnetic clutch is provided in each drive transmission path to selectively switch the drive transmission path. Further, since the one-way clutch 4 does not consume electric power, the electric power consumption of the device can be suppressed as compared with the case where the electromagnetic clutch is provided in each drive transmission path.

Further, in the first embodiment, the one-way clutch 4 and the first electromagnetic clutch 5 are provided on the rotating shaft 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 rotating shaft rotatably supported by a side plate 9 and a bracket 8 via bearings. Therefore, if they are provided on different shafts, two rotating 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 compared with the case where the one-way clutch 4 and the first electromagnetic clutch 5 are provided on different shafts. Two bearings can be reduced. Therefore, as compared with the case where the one-way clutch 4 and the first electromagnetic clutch 5 are provided on different shafts, 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 rotating shaft X on which the first input gear 7 and the second input gear 3 are arranged, the first output gear 6a and the first output gear 6a arranged on the output fixed shaft U are provided. The two output gears 6b can be integrated. As a result, the number of parts can be reduced and the assembly man-hours can be reduced as compared with the configuration in which the first output gear 6a and the second output gear 6b are separate bodies. Further, the shaft supporting the first output gear 6a and the second output gear 6b can be a fixed shaft. As a result, bearings can be eliminated, the number of parts can be reduced, and the cost of the device can be reduced as compared with the case of using a rotating shaft.

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

Further, in the present embodiment, the image forming speed is changed according to the type of the paper 400 so that the paper 400 passes through the secondary transfer nip and the fixing nip at a transport speed suitable for obtaining high image quality. There is. For example, in the case of thick paper, the rotation speed of the secondary transfer roller 59 and the rotation speed of the fixing roller 230a are set to the thick paper transport mode, which is a second drive mode in which the rotation speed of the fixing roller 230a is slower than that of plain paper, and the secondary transfer position and fixing are performed. The speed of the paper 400 passing through the nip portion of the roller pair 230 is slowed down. Further, the speed ratio of the first resist roller 29a to the rotation speed of the secondary transfer roller 59 is set so that the paper is not pulled or over-fed between the resist rollers 29 and the secondary transfer roller 59. , The rotation speed is changed so that the same speed ratio as that of plain paper is maintained.

The relationship between the rotation speeds of each roller is as follows, based on the rotation speed of the secondary transfer roller 59. That is, assuming that the rotation speed of the secondary transfer roller 59 in the case of plain paper is Vf, the rotation speed of the first resist roller 29a is Vf × (1 + α), and the rotation speed of the fixing roller 230a is Vf × (1 + β). It is a relationship. For thick paper, the rotation speed of the secondary transfer roller 59 is changed from Vf to Vt (Vf> Vt), the rotation speed of the first resist roller 29a is Vf × (1 + α), and the rotation 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 rotation speed of the secondary transfer roller 59 on plain paper is 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 resist roller 29a is 178.712 [mm / s]. Therefore, the relative speed ratio between the first resist roller 29a and the fixing roller 230a at this time is about 1%.

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

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

In the first embodiment, the number of teeth of the motor gear 1a is Z1, the number of teeth of the resist feed input gear 11 is Z2, the number of teeth of the first input gear 7 is Z3, and the number of teeth of the second input gear 3 is Z4. Assuming that the number of teeth of the 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 resist gear 13 is Z7, the reduction ratio V1 when driving transmission is performed using the first drive transmission path D1 is , It becomes as follows.
V1 = (Z2 / Z1) x (Z5 / Z3) x (Z7 / Z6) ... (1)

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

The relative reduction ratio (V1 / V2) [%] 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) x (Z5 / Z3) x (Z7 / Z6)}
/ {(Z2 / Z1) x (Z7 / Z4)}] x 100
= {(Z5 / Z3) x (Z4 / Z6)} x 100 ... (3)

As can be seen from the above equation (3), the relative reduction ratio is determined by the reduction ratio (Z5 / Z3) of the first drive transmission path D1 and the reduction ratio (Z4 / Z6) of the second drive transmission path D2. As described above, in the present embodiment, the two gears of the first drive transmission path D1 (first input gear 7 and the first output gear 6a) and the two gears of the second drive transmission path D2 (second input gear 3). And 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. It is 989, and the relative reduction ratio is 0.2 [%].

As described above, in the first embodiment, the relative speed ratio can be set to 1% or less with less than 100 teeth of the gears constituting each drive transmission path. As a result, the gears of each drive transmission path can be made smaller in diameter, and the relative speed ratio can be made 1% or less, and the device can be miniaturized. This is because each drive transmission path is provided with a plurality of non-common gears. In this way, by providing a plurality of non-common gears in each drive transmission path, it is possible to make the gear modules and twist angles 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 electromagnetic clutch is provided on the other side so that the drive transmission path can be selectively switched by turning the electromagnetic clutch ON / OFF.

Further, in the speed switching mechanism D of the first embodiment, the first output gear 6a and the second output gear 6b are provided coaxially with the first input gear 7 for transmitting the driving force to the first output gear 6a. A second input gear 3 that transmits a driving force to the second output gear 6b is also provided coaxially. As a result, the size of the device can be reduced 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, each drive transmission path is composed of two drive transmission members, an input gear and an output gear, so that the relative speed ratio is set to 1% or less with the minimum number of drive transmission members. There is. As a result, it is possible to suppress an increase in cost due to an increase in the number of parts.

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 shaft Y via the resist electromagnetic clutch 12, and the first resist roller 29a is rotationally driven. Further, the driving force transmitted to the registration gear 13 is input to the paper feed gear 16 via the paper feed idler gear 14. When the paper feed electromagnetic clutch 15 is ON, the driving force is transmitted to the shaft Z of the feed roller 27a via the paper feed electromagnetic clutch 15, and the feed roller 27a is rotationally driven.

Further, the feed roller 27a to which the driving force is transmitted via the second drive transmission mechanism 62 has a relative speed ratio with the first resist roller 29a so that the paper is not pulled or fed too much between the resist rollers 29. It is necessary to change the rotation speed so that the same relative speed ratio is maintained between the case of plain paper and the case of thick paper.

In the first embodiment, as shown in FIG. 2, the driving force is transmitted to the feed roller 27a via the resist gear 13 which is the output member to which the speed switching mechanism D outputs the driving force. As a result, 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 resist 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. As a result, the speed of the feed roller 27a is changed by the speed switching mechanism D in the same manner as the first resist roller 29a, and the relative speed ratio between the feed roller 27a and the first resist roller 29a is set between that of thick paper and that of plain paper. At times, the same relative velocity ratio can be maintained.

FIG. 4 is a control flow diagram showing an example of control of the drive device 60.
First, the control unit of the image forming apparatus 100, which is a control means, checks whether or not the conveyed paper 400 is thick paper (S1). The information on the paper thickness of the paper 400 to be conveyed can be obtained by, for example, when the paper 400 is set in the sheet accommodating cassette 26, the operation display unit is operated to input the paper thickness information of the paper 400 set by the user. Can be grasped.

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

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

By driving the motor 1 at a second rotation speed Va that is slower than the first rotation speed Vb, the fixing roller 230a is rotationally driven at a slow rotation speed. As a result, even if the paper is thick, the toner image on the paper can be sufficiently heated at the fixing nip, the toner image can be satisfactorily melted, and good fixability can be obtained. In the present embodiment, the second rotation speed Va is reduced by 0.3% to 0.6% with respect to the first rotation speed Vb.

On the other hand, in the case of thick paper, the first resist roller 29a and the feed roller 27a are rotationally driven by transmitting the driving force through the first drive transmission path D1. In the first drive transmission path D1, when the motor 1 is driven at the second rotation speed Va, the rotation speeds of the first resist roller 29a and the feed roller 27a are set to the rotation speed Vt of the secondary transfer roller 59 when the paper is thick. On the other hand, the speed ratio is set to be the same as that of plain paper. As a result, even if the rotation speed of the motor 1 is reduced in order to reduce the rotation speed of the fixing roller 230a in the case of thick paper, the speed ratio between the resist roller to 29 and the secondary transfer roller 59 can be maintained. As a result, the paper can be satisfactorily conveyed to the secondary transfer nip even when the paper is thick, and the toner image on the intermediate transfer belt 48 can be satisfactorily transferred to the paper 400.

Further, the relative speed ratio of the feed roller 27a to the first resist roller 29a is maintained at the same relative speed ratio between the case of plain paper and the case of thick paper. As a result, it is possible to suppress the occurrence of paper pulling between the feed roller 27a and the resist roller pair 29 and buckling of the paper due to overfeeding during the transportation of plain paper or the transportation of thick paper.

In FIG. 6, the first drive transmission path D1 is used for thick paper, and the second drive transmission path D2 is used for non-thick paper, but the second drive transmission path D2 is used for thick paper. When paper is not thick, the first drive transmission path D1 may be used. However, it is preferable to use the second drive transmission path D2 for plain paper that is frequently used. This is because when the second drive transmission path D2 is used, the first electromagnetic clutch 5 is OFF, so that the power consumption of the device can be suppressed. Further, the life of the first electromagnetic clutch 5, which is generally more expensive than the one-way clutch, can be extended, and the running cost of the device can be reduced.

Further, in the first embodiment, the first resist roller 29a and the feed roller 27a are rotationally driven by the second drive transmission mechanism 62. For example, the first resist roller 29a and the first transfer roller 28a May be driven and transmitted by the second drive transmission mechanism 62. Further, the first resist roller 29a, the first transport roller 28a, and the feed roller 27a may be driven and transmitted by the second drive transmission mechanism 62. Further, the drive force may be transmitted to the secondary transfer roller 59 and the first resist roller 29a by the second drive transmission mechanism 62.

Further, the speed switching mechanism D may be provided in the first drive transmission mechanism 61 that transmits the driving force to the fixing roller 230a, but when the fixing roller 230a is rotated in the reverse direction during the jam processing, the speed switching mechanism D is driven second. It is provided in the transmission mechanism 62.

As shown in FIG. 1, the fixing nip portion is covered with a case of the fixing device 20, and the fixing nip portion cannot be easily accessed by the user. Therefore, if a small-sized paper jam occurs at the fixing nip portion, it is difficult to remove the small-sized paper. Therefore, the image forming apparatus 100 performs a jam processing operation in which the motor 1 is rotated in the reverse direction and the fixing roller 230a is rotated in the reverse direction when a small-sized paper jam occurs in the fixing nip portion. By performing the jam processing operation, the rear end of the paper 400 can be exposed from the fixing device 20, and the paper 400 can be easily taken out.

On the other hand, even if the paper is jammed by the resist roller pair 29 or the separating means 27, unlike the fixing device 20, the nip portion is not covered with the case, so that the user jammed the paper 400 without performing reverse rotation or the like. Easy access to. Therefore, the first resist roller 29a and the feed roller 27a can easily remove the paper without rotating in the reverse direction during the jam treatment.

When the fixing roller 230a is rotated in the reverse direction during the jam processing, the motor 1 is rotated in the reverse direction. When the motor 1 is rotated in the reverse direction, if the first electromagnetic clutch 5 is OFF, the rotation shaft X rotates in the reverse direction relative to the one-way clutch 4, so that the second input gear 3 and the one-way clutch 4 rotate. It runs idle with respect to the axis X. Therefore, the driving force of the motor 1 is not transmitted. On the other hand, when the motor 1 is rotated in the reverse direction and the first electromagnetic clutch 5 is turned on, the rotating shaft X rotates in a positive direction relative to the one-way clutch 4, so that the driving force from the rotating shaft X to the one-way clutch 4 Is transmitted. As a result, the driving force is transmitted from both 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 tooth breakage occur. There is a problem that there is a risk. 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 speed switching mechanism D is provided in the second drive transmission mechanism 62 and the first electromagnetic clutch 5 is turned off, when the motor 1 is rotated in the reverse direction and the fixing roller 230a is rotated in the reverse direction, the first electromagnetic clutch 5 is turned off. 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 the drive device 60A according to the second embodiment.
This second embodiment is a modification of the first embodiment, and both the first drive transmission path D1 and the second drive transmission path D2 of the speed switching mechanism D are configured by using a timing belt. The first drive transmission path D1 includes a first input pulley 71 supported by the rotation shaft X, a first output pulley 61a provided on the output fixed shaft U, a first input pulley 71, and a first output pulley 61a. It is provided with a first timing belt 72, which is a stretched toothed belt. Further, the first electromagnetic clutch 5 is provided, which is engaged with the first input pulley 71 from the axial direction and is attached to the rotating shaft X.

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

Further, the output fixed shaft U is provided with an output gear 6c that meshes with the resist gear 13, and the output gear 6c, the first output pulley 61a, and the second output pulley 61b are integrally formed. 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 drive transmission path D2. The relative reduction ratio is determined by the ratio of the number of teeth of the two input pulley 3a to 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 based on 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. And the relative reduction ratio (V1 / V2) when the second drive transmission path D2 is used can be adjusted.

For example, an S2M type timing belt is used as the timing belt of one drive transmission path, and an S3M type timing belt is used as the timing belt of the other drive transmission path. With 100 teeth or less, the relative reduction ratio (V1 / V2) can be 1% or less.

Further, also in the second 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. As a result, when the first electromagnetic clutch 5 is turned on, the second input pulley 3a rotates faster than the rotating shaft X, and the rotating shaft X rotates relatively in the opposite direction to the second input pulley 3a. Therefore, the one-way clutch 4 can be idled with respect to the rotation axis X. On the other hand, when the first electromagnetic clutch 5 is OFF, only the rotating shaft X is rotationally driven, so that the rotating shaft X rotates in a positive direction relative to the second input pulley 3a. Therefore, when the first electromagnetic clutch 5 is OFF, the driving force of the rotating shaft X is transmitted to the second input pulley 3a via the one-way clutch 4.

Further, 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 the axes are different from each other. The size of the device can be reduced as compared with the case where the device is provided in.

Further, by configuring each drive transmission path with a timing belt, even if the first resist roller 29a is arranged at a position away from the motor 1, each drive transmission is performed by a gear train in which a plurality of gears are meshed with each other. Compared with the case where the path is configured, the number of parts can be reduced and drive transmission can be performed to the first resist roller 29a and the feed roller 27a. As a result, it is possible to suppress an increase in the cost of the device.
As shown in the first embodiment, each drive transmission path of the speed switching mechanism D is composed of a gear train in which a plurality of gears are meshed with each other, so that the speed switching mechanism D is worn out, etc., as compared with the case where the timing belt is used. It has the effect of being able to be strong against the ground and increasing its durability.

[Example 3]
FIG. 6 is a schematic cross-sectional view of the drive device 60B according to the third embodiment.
The drive device 60B according to the third embodiment is a modification of the first embodiment, in which the first electromagnetic clutch 5 and the one-way clutch 4 are provided on different shafts from each other.
In the third embodiment, the second output gear 6b is meshed with the resist paper feed input gear 11, and the resist paper feed input gear 11 is used as the input gear of the second drive transmission path D2. Further, in the third embodiment, the second output gear 6b is separated from the first output gear 6a and is provided on the outer peripheral surface of the one-way clutch 4. The one-way clutch 4 is provided on the 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 that meshes with the registration gear 13 and outputs a driving force to the registration gear 13 so as to rotate integrally with the output rotation shaft X2. It is supported by X2. Further, in the one-way clutch 4 of the third embodiment, when the output rotation shaft X2 rotates in a positive direction relative to the one-way clutch 4, the drive transmission from the second output gear 6b to the output rotation shaft X2 is cut off. The drive force is transmitted when the vehicle rotates in the reverse direction.

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 that the driving force is not transmitted from the first output gear 6a to the output rotating shaft X2. The output rotation shaft X2 is not rotationally driven. On the other hand, the driving force is transmitted from the resist paper feed 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 shaft X2 rotates in the opposite direction to the one-way clutch 4. In the third embodiment, as described above, the one-way clutch 4 drives the output rotation shaft X2 from the second output gear 6b to the output rotation shaft X2 when the output rotation shaft X2 rotates in the opposite direction to the one-way clutch 4. It is a structure in which 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 shaft X2. Then, the driving force is transmitted from the output gear 6c of the drive output member 6 that rotates integrally with the output rotation shaft X2 to the resist gear 13.

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 shaft X2 is rotationally driven. Also in the third embodiment, the reduction ratio of the second drive transmission path D2 (the reduction ratio between the registration 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). It is made larger than the reduction ratio) between the input gear 7 and the first output gear 6a. Therefore, the rotation speed of the output rotation shaft X2 that is rotationally driven using the first drive transmission path D1 is faster than the rotation speed of the second output gear 6b. As a result, the output rotation shaft X2 rotates in a positive direction relative to the one-way clutch 4. As described above, in the one-way clutch 4 of the third embodiment, when the output rotation shaft X2 rotates in a positive direction relative to the one-way clutch 4, the driving force from the second output gear 6b to the output rotation shaft X2 is applied. It is a configuration that is cut off. Therefore, when the first electromagnetic clutch 5 is ON, the driving force is cut off from the second output gear 6b to the output rotating shaft X2, and the output gear 6c of the drive output member 6 passes through the first drive transmission path D1 to the resist gear 13. The driving force is transmitted to.

As described above, also in the third embodiment, the drive transmission path can be selectively switched by 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 feed 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 resist gear 13 is Z7, the reduction ratios V1 and V2 using each drive transmission path are as follows.
V1 = (Z2 / Z1) x (Z4 / Z3) x (Z7 / Z6)
V2 = (Z2 / Z1) x (Z5 / Z2) x (Z7 / Z6)
= (Z5 / Z1) × (Z7 / Z6)

From the above, the relative reduction ratio (V1 / V2) [%] 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) x (Z4 / Z3) x (Z7 / Z6)}
/ (Z4 / Z1) x (Z7 / Z6)] x 100
= (Z2 / Z5) x (Z4 / Z3) x 100

Therefore, even in the third embodiment in which the resist feed feed input gear 11 is used as the second input gear, the relative reduction ratio is the same as in the first embodiment, and the number of teeth Z3 of the first input gear 7 of the first drive transmission path D1. The ratio of the first output gear 6a of the first drive transmission path D1 to the number of teeth Z4 of the first output gear 6a, and the number of teeth Z2 of the resist feed 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 of the gear 6b to the number of teeth Z5. Therefore, as in the first embodiment, the number of teeth in each drive transmission path can be 100 teeth or less, and the relative speed ratio can be 1% or less.

[Example 4]
7A and 7B are schematic configuration views of the drive device 60C according to the fourth embodiment, FIG. 7A is a schematic cross-sectional view, and FIG. 7B is a view seen from the bracket 8 side.
This Example 4 is a modification of the first embodiment, and is generally a (first electromagnetic clutch) of an electromagnetic clutch that has a shorter life than a drive transmission member such as a gear or a pulley and needs to be replaced regularly. 5. The structure is such that the replaceability of the resist electromagnetic clutch 12 and the paper feed electromagnetic clutch 15) is improved.

In the fourth embodiment, in order to improve the interchangeability of the electromagnetic clutches 5, 12 and 15, the electromagnetic clutches 5, 12 and 15 are placed on the outermost side of the device with respect to the drive transmission member coaxially provided. When viewed from the bracket side, the electromagnetic clutches 5, 12, and 15 were arranged so as not to overlap with the drive transmission member. Specifically, the first electromagnetic clutch, the first input gear 7, the one-way clutch 4 (second input gear 3), and the resist feed input gear 11 provided on the rotating shaft X to which the first electromagnetic clutch 5 is attached are used as the first electromagnetic clutch. It was arranged on the roller side (inside the device) of 5. Further, the resist gear 13 arranged coaxially with the resist electromagnetic clutch 12 provided on the resist shaft Y was arranged on the roller side (inside the device) of the resist electromagnetic clutch 12. Further, the paper feed gear 16 arranged coaxially with the paper feed electromagnetic clutch 15 provided with the shaft Z of the feed roller 27a is arranged on the roller side (inside of the device) of the paper feed electromagnetic clutch 15.

Further, in the fourth embodiment, the diameters of the bearings 8b, 8c, 8d attached to the bracket 8 to receive the shafts X, Y, Z to which the electromagnetic clutches 5, 12 and 15 are fixed are set to the diameters of the electromagnetic clutches 5, The outer diameter is 12 or 15 or more. Each bearing 8b, 8c, 8d is fixed to the bracket 8 by screws 181b, 181c, 181d.

FIG. 8 is a schematic configuration diagram of the drive device 60C of the fourth embodiment in which the bearings 8b, 8c, 8d are removed from the bracket 8, (a) is a schematic cross-sectional view, and (b) is from the bracket side. It is a schematic view seen.
As shown in FIG. 8, when the bearing 8b that receives the rotating shaft X is removed from the bracket 8, it is attached to the rotating shaft X, and is attached to the rotating shaft X, the first input gear 7, the one-way clutch 4 (second input gear 3), and the resist feed input gear. The first electromagnetic clutch 5 arranged on the outside (bracket side) of the device with respect to 11 is exposed. From this, the first electromagnetic clutch is inserted through the hole 81b of the bracket 8 into which the bearing 8b is fitted without removing the first input gear 7, the one-way clutch 4 (second input gear 3), and the resist paper feed input gear 11 from the rotating shaft X. You can access 5.

Further, the inner diameter of the hole 81b of the bracket 8 into which the bearing 8b fits is larger than the outer diameter of the first electromagnetic clutch 5. Therefore, the first electromagnetic clutch 5 can be removed from the rotating shaft X from the hole 81b, and a new first electromagnetic clutch 5 can be attached to the rotating shaft X from the hole 81b. As a result, the first electromagnetic clutch 5 can be easily replaced.

When the bearing 8c that receives the resist shaft Y is removed from the bracket 8, the resist electromagnetic clutch 12 that is attached to the resist shaft Y and is arranged outside the device (bracket side) of the resist gear 13 is exposed. From this, the resist electromagnetic clutch 12 can be accessed from the hole 81c of the bracket 8 into which the bearing 8c is fitted without removing the resist gear 13 from the resist shaft Y.

Further, the inner diameter of the hole 81c of the bracket 8 into which the bearing 8c fits is larger than the outer diameter of the resist electromagnetic clutch 12. Therefore, the resist electromagnetic clutch 12 can be removed from the resist shaft Y from the hole 81c, and a new resist electromagnetic clutch 12 can be attached to the resist shaft Y from the hole 81c. As a result, the resist electromagnetic clutch 12 can be easily replaced.

Further, when the bearing 8d that receives the shaft Z of the feed roller 27a is removed from the bracket 8, the paper feed electromagnetic clutch 15 attached to the shaft Z and arranged outside the device (bracket side) of the paper feed gear 16 is exposed. To do. As a result, the paper feed electromagnetic clutch 15 can be accessed from the hole 81d of the bracket 8 into which the bearing 8d is fitted without removing the paper feed gear 16 from the shaft Z of the feed roller 27a.

The inner diameter of the hole 81d of the bracket 8 into which the bearing 8d fits is larger than the outer diameter of the paper feed electromagnetic clutch 15. Therefore, the paper feed electromagnetic clutch 15 can be removed from the shaft Z of the feed roller 27a from the hole 81d, and a new paper feed electromagnetic clutch 15 can be attached to the shaft Z from the hole 81d. As a result, the paper feed electromagnetic clutch 15 can be easily replaced.

[Example 5]
9A and 9B are schematic configuration views of the drive device 60D according to the fifth embodiment, FIG. 9A is a schematic cross-sectional view, and FIG. 9B is a view seen from the bracket side.
The fifth embodiment is a modification of the third embodiment, and has a configuration in which the drive device 60B of the third embodiment has improved interchangeability of the electromagnetic clutches 5, 12, and 15.

In the fifth embodiment, unlike the third embodiment, the first output gear 6a of the first drive transmission path D1 is meshed with the resist paper feed input gear 11, and the resist paper feed input gear 11 is used as the first input gear. ing. Further, the first electromagnetic clutch 5 is provided on the output rotation shaft X2 and is engaged with the first output gear 6a from the axial direction. Further, the drive output member 6 is composed of a second output gear 6b of the second drive transmission path D2 and an output gear 6c. Then, the first electromagnetic clutch 5 is arranged outside the device (bracket side) from the drive output member 6 and the first output gear 6a provided on the output rotation shaft X2, and when viewed from the bracket side, the first electromagnetic clutch 5 is arranged. The clutch 5 is prevented from overlapping with the drive transmission member.

Further, also in the fifth embodiment, as in the fourth embodiment, the diameters of the bearings 8e, 8c, 8d attached to the bracket 8 that receives the shafts X2, Y, Z to which the electromagnetic clutches 5, 12, 15 are fixed are set. , The outer diameter of each electromagnetic clutch 5, 12, 15 or more.

10A and 10B are schematic configuration views of the drive device 60D of the fifth embodiment in which the bearings 8e, 8c, and 8d are removed from the bracket 8, FIG. 10A is a schematic sectional view, and FIG. 10B is a schematic sectional view from the bracket side. It is a schematic view seen.
In the fifth embodiment as well, as in the fourth embodiment, the bearings 8e, 8c, 8d that receive the shafts X2, Y, Z to which the electromagnetic clutches 5, 12, and 15 are fixed are removed from the bracket 8, so that each electromagnetic clutch is removed. Clutches 5, 12 and 15 are exposed. Then, the electromagnetic clutches 5, 12 and 15 can be replaced from the holes 81e, 81c and 81d of the bracket 8 into which the bearings 8e, 8c and 8d are fitted.

[Example 6]
11A and 11B are schematic configuration views of the drive device 60E according to the sixth embodiment, FIG. 11A is a schematic cross-sectional view, and FIG. 11B is a view seen from the bracket 8 side.
In the drive device 60E of the sixth embodiment, the motor 1 is provided on the inner surface of the device facing the fixing roller 230a, the first resist roller 29a, and the like of the side plate 9. Further, the internal tooth gear 18 is provided, and the driving force is transmitted from the internal tooth gear 18 to the first drive transmission mechanism 61 and the second drive transmission mechanism 62.

The internal tooth gear 18 has a tubular shape with the bracket side closed, and is rotatably supported by a third fixed shaft S3 fixed to the side plate 9 and the bracket 8. Internal teeth 18a are formed on the inner peripheral surface of the internal tooth gear 18, and the motor gear 1a meshes with the internal teeth 18a. Further, external teeth 18b are formed on the outer peripheral surface of the internal tooth gear 18, and the first external tooth gear 2a of the fixing idler gear 2 and the resist paper feed input gear 11 mesh with the external teeth 18b. ..

In the drive device 60E of the sixth embodiment, the motor 1 is provided on the inner surface of the device facing the fixing roller 230a, the first resist roller 29a, and the like of the side plate 9, and the first drive transmission mechanism 61 and the second drive transmission are transmitted. It is arranged on the inner side of the device rather than the mechanism 62. As a result, the sound of the motor 1 can be blocked by the side plate 9, the bracket 8, and the like, the sound of the motor 1 can be suppressed from leaking to the outside of the device, and the device can be made quieter.

Further, by engaging the motor gear 1a with the internal teeth 18a of the internal tooth gear 18, the engagement rate with the motor gear 1a can be improved, and vibration and noise can be suppressed. Further, the meshing portion with the motor gear 1a can be covered with the internal tooth gear 18, and the meshing noise can be shielded by the internal tooth gear 18. Further, since the bracket side of the internal tooth gear 18 is closed, it is possible to suppress the meshing noise from leaking to the outside. As a result, the device can be made quieter.

Further, also in the sixth embodiment, the electromagnetic clutches 5, 12 and 15 are arranged on the outer side in the axial direction (bracket side), and the electromagnetic clutches 5, 12 and 15 receive the fixed shafts X, Y and Z. The diameters of the bearings 8b, 8c, and 8d are set to be equal to or larger than the outer diameters of the electromagnetic clutches 5, 12, and 15.

12A and 12B are schematic configuration views of the drive device 60E of the sixth embodiment in which the bearings 8b, 8c, 8d are removed from the bracket 8, FIG. 12A is a schematic cross-sectional view, and FIG. 12B is a schematic sectional view from the bracket side. It is a schematic view seen.
Also in the sixth embodiment, the electromagnetic clutches 5, 12 and 15 are obtained by removing the bearings 8b, 8c and 8d that receive the shafts X, Y and Z to which the electromagnetic clutches 5, 12 and 15 are fixed from the bracket 8. Is exposed. Then, the electromagnetic clutches 5, 12 and 15 can be replaced from the holes 81e, 81c and 81d of the bracket 8 into which the bearings 8b, 8c and 8d are fitted.

In the sixth embodiment, by providing the motor 1 on the side plate 9, the motor 1 does not get in the way when the electromagnetic clutches 5, 12 and 15 are replaced, as compared with the case where the motor 1 is provided on the bracket 8, and the replacement work is performed. It can enhance the sex.

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

The first drive transmission path D1 includes a first input gear 7, a first idler gear 19, a first output gear 6a, and a first electromagnetic clutch 5. The second drive transmission path D2 includes a second input pulley 3a, a second output pulley 61b, a second timing belt 73 which is a toothed belt, and a one-way clutch 4.

The first idler gear 19 has a first gear portion 19a that meshes with the first input gear 7 and a second gear portion 19b that meshes with the first output gear 6a, and is fixed to the side plate 9 and the bracket 8. (3) It is rotatably supported by the fixed shaft S3. Further, the first output gear 6a, the second output pulley 61b and the output gear 6c are formed on the drive output member 6.

Further, in the seventh embodiment, the second drive transmission path D2 configured by using the timing belt is used in the plain paper mode (conveyance mode other than thick paper) in which the transport speed (rotational speed of the motor 1) is high, and the first The drive transmission path D1 is used in the thick paper mode (thick paper transport mode). In the plain paper mode in which the rotation speed 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 plain paper mode, when the first drive transmission path D1 composed of only the external tooth gears is used, the teeth may hit each other due to the load fluctuation at the start of driving, and noise or the like may be generated. On the other hand, in the plain paper mode, by using the second drive transmission path D2 configured by using the timing belt, the timing belt is elastically deformed and the load fluctuation at the start of driving can be absorbed. As a result, it is possible to suppress the generation of noise and the like.

Further, since the first drive transmission path D1 is composed of only the external tooth gear, it is more resistant to wear and the like than the timing belt, and has high durability against repeated use. Therefore, by configuring the first drive transmission path D1 used in the thick paper mode in which the transport speed (rotational speed of the motor 1) is slow and the load fluctuation at the start of driving is small, only the external gears are used, the durability of the drive device can be maintained. You can improve your sex. As described above, in the seventh embodiment, both durability and noise suppression can be achieved at the same time.

Further, the driving device of Examples 1 to 7 is not only for driving the fixing roller 230a, the first resist roller 29a, and the feed roller 27a, which are transport members for transporting the paper 400 of the image forming apparatus 100, but also, for example, a developing roller. It can also be used to drive a rotating body used for image formation such as a photoconductor, a primary transfer roller and an intermediate transfer belt 48. Further, the driving devices of Examples 1 to 7 may be used to drive the transporting member for transporting the document 410 of the document automatic feeding device (ADF: Auto Document Feeder) 310 shown in FIG.

The above description is an example, and the effect peculiar to each of the following aspects is exhibited.
(Aspect 1)
Of the two drive transmission paths in which the reduction ratios are different from each other and the driving force of the drive source such as the motor 1 is transmitted to the output target rotating body such as the resist gear 13, the first drive transmission path D1 having the smaller reduction ratio is used as an image forming device. A drive transmission switching means such as a first electromagnetic clutch 5 that selectively switches between a state in which the driving force of the drive source is transmitted and a state in which the driving force of the drive source is cut off is provided by a control means such as a control unit of 100, and a reduction ratio is large. (2) In a speed switching device such as a speed switching mechanism D provided with a one-way clutch 4 in the drive transmission path D2, the first final drive transmission of the first output gear 6a or the like in 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 that transmits the drive force to the member and the last drive force in the second drive transmission path D2 are transmitted and arranged coaxially with the first final drive transmission member. A second drive transmission member that transmits a driving force to the second final drive transmission member such as the second output gear 6b is provided 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. Since the second drive transmission member such as the second input gear 3 that transmits the driving force to the second final drive transmission member such as the second output gear 6b of D2 is provided coaxially, they are provided on different shafts. Compared with the above, it is possible to reduce the size of the speed switching device such as the speed switching mechanism D.

(Aspect 2)
In the first aspect, 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 are input drives in which the driving force is input at the beginning of each drive transmission path. It is a transmission member.
According to this, as described in the first embodiment, each drive transmission path is composed of two drive transmission members, and the relative speed ratio can be reduced to 1% or less with the minimum number of drive transmission members. As a result, it is possible to suppress an increase in cost due to an increase in the number of parts.

(Aspect 3)
In the first or second aspect, the first drive transmission path D1 and the second drive transmission path D2 are gear drive transmission paths that perform drive transmission by meshing 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 set to 1% or less with 100 or less teeth of each gear. It is possible to suppress an increase in the diameter of the gear and an increase in the size of the device.
Further, the durability can be improved 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 first or second aspect, the first drive transmission path D1 and the second drive transmission path D2 are belt drive transmission paths for performing drive transmission using a belt.
According to this, as described with reference to the second embodiment, the number of teeth of the gear drive transmission path and the gear and the number of teeth of the pulley of the belt drive transmission path are 100 teeth or less, and the gear drive transmission path and the belt drive transmission are performed. The reduction ratio with the path can be reduced to 1% or less, the increase in diameter of gears and pulleys can be suppressed, and the increase in size of the device can be suppressed.
Further, when the output target rotating body such as the first resist roller 29a is arranged at a position away from the drive source such as the motor 1, compared with the case where each drive transmission path is configured by a gear train in which a plurality of gears are meshed with each other. Therefore, the number of parts can be reduced and drive transmission can be performed to the rotating body to be output, and the cost increase of the device can be suppressed.

(Aspect 5)
In any of aspects 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 as compared with 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. It is possible to suppress an increase in the cost of the device.

(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 coaxially provided 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. 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, from the first final drive transmission member or the second final drive transmission member to the resist gear 13 and the like. Output The driving force is output to the 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 configured. In comparison, the number of parts can be reduced, and the assembly man-hours can be reduced. Further, the number of parts is reduced as compared with the case where a drive transmission member such as a gear that outputs a driving force is provided on an output target rotating body such as a resist gear 13 separately from the first final drive transmission member and the second final drive transmission member. can do.

(Aspect 7)
In any of 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 aspects 1 to 7, the drive transmission switching means is an electromagnetic clutch.
According to this, by controlling ON / OFF of the electromagnetic clutch by a control means such as a control unit of a printer, it is possible to selectively switch between a state in which the driving force is transmitted and a state in which the transmission of the driving force is cut off.

(Aspect 9)
In any of 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 overlaps with any of the plurality of drive transmission members constituting each drive transmission path. It was arranged so that it would not become.
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, and the drive transmission switching means can be accessed. Can be exchanged.

(Aspect 10)
In aspect 9, a bearing such as a bearing 8b that is provided on one side in the axial direction such as the bracket side of the drive transmission switching means such as the first electromagnetic clutch 5 and receives a shaft such as a rotating shaft 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 side plate such as a bracket 8 that supports the shaft via a bearing member. It is provided so as to be removable from the side plate such as the bracket 8.
According to this, as described in the fourth embodiment, by removing the bearing member such as the bearing 8b, the drive transmission switching means is accessed from the hole for fitting the bearing member provided in the side plate such as the bracket 8. The drive transmission switching means can be replaced. As a result, the drive transmission switching means can be easily replaced as compared with the case where the side plate such as the bracket 8 is removed and the drive transmission switching means is replaced.

(Aspect 11)
In a drive device including a drive source such as a motor 1 and a drive transmission unit that transmits the drive force of the drive source to a rotating body (in this embodiment, a fixing roller 230a, a first resist roller 29a, and a feed roller 27a). The drive transmission unit includes the speed switching device according to any one of aspects 1 to 9.
According to this, the rotation speed of the rotating body can be switched without changing the rotation speed of the drive source.

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

(Aspect 13)
In aspect 12, the first drive transmission unit such as the first drive transmission mechanism 61 that transmits the driving force to the forward / reverse rotating body such as the fixing roller 230a that rotates forward / reverse, which is one of the plurality of rotating bodies, and the plurality of the above. A second drive such as a second drive transmission mechanism 62 that transmits a driving force to a unidirectional rotating body (first resist roller 29a, feed roller 27a in this embodiment) that rotates only in one direction, which is one of the rotating bodies. A speed switching device such as a speed switching mechanism D provided with a transmission unit is provided in the second drive transmission unit.
According to this, as described in the first embodiment, the drive source such as the motor 1 can be rotated in the reverse direction, and the forward / reverse rotating body such as the fixing roller 230a which is rotated in the forward / reverse direction can be rotated in the reverse direction. On the other hand, if 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 rotated in the reverse direction, the unidirectional rotating body (in the present embodiment, the first resist roller 29a, The driving force is not transmitted to the feed roller 27a), and the unidirectional rotating body does not rotate in the direction opposite to the one direction.

(Aspect 14)
In aspect 13, the forward / reverse rotating body is the fixing roller 230a, and the unidirectional rotating body is the resist roller.
According to this, as described in the first embodiment, when a paper jam of a small size paper occurs at the fixing nip portion, the fixing roller 230a is rotated in the reverse direction to remove the rear end of the paper 400 from the fixing device 20. It can be exposed to make it easier to take out the paper 400.

(Aspect 15)
In the 13th or 14th aspect, the first drive mode, which is a plain paper transport mode for transporting plain paper in which the drive source such as the motor 1 is rotated at the first rotation speed, and the drive source are set from the first rotation speed. It also has a second drive mode, which is a thick paper transport mode for transporting thick paper that is rotated at a slow rotation speed, and switches the speed of the speed switching device when the drive mode is switched.
According to this, as described in the embodiment, a rotating body such as a fixing roller 230a in which the driving force is transmitted by the first drive transmission unit such as the first drive transmission mechanism 61, and a second such as the second drive transmission mechanism 62. The relative speed ratio with the rotating body such as the first resist roller 29a to which the driving force is transmitted by the drive transmission unit is set between the first drive mode, which is the plain paper transport mode, and the second drive mode, which is the thick paper transport mode. It can be different from time to time.

(Aspect 16)
In any of aspects 10 to 15, an internal gear such as an internal gear 18 that meshes with an output gear portion such as a motor gear 1a provided on an output shaft of a drive source such as a 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 is improved, and vibration and noise can be suppressed. Further, the meshing portion with the output gear portion can be covered with an internal gear such as an internal gear 18, and the meshing noise can be shielded by the internal gear, and the noise can be suppressed.

(Aspect 17)
In any of aspects 10 to 16, the drive source such as the motor 1 is provided on the rotating body side, which is the inner side of the image forming apparatus 100, with respect to the drive transmission unit in the axial direction.
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 the image forming apparatus 100 is provided on the side opposite to the rotating body side which is the outer side of the image forming apparatus 100. It is possible to suppress the output, and it is possible to reduce the noise of the image forming apparatus 100.

(Aspect 18)
Of the two drive transmission paths that have different reduction ratios from the drive source such as the motor 1 and transmit the drive force of the drive source to the output target rotating body such as the resist gear 13, the first drive transmission path D1 having the smaller reduction ratio , A drive transmission switching means such as a first electromagnetic clutch 5 that selectively switches between a state in which the driving force of the driving source is transmitted and a state in which the driving force is cut off is provided by a control means such as a control unit of the image forming apparatus 100, and decelerates. In the drive device 60F provided with a speed switching device D such as a speed switching mechanism D provided with a one-way clutch 4 in the second drive transmission path having a large ratio, either the first drive transmission path D1 or the second drive transmission path D2 is provided. One is a gear drive transmission path that performs drive transmission by meshing gears, and the other is a belt drive transmission path that performs drive transmission using a belt, and rotates the drive source at the first rotation speed. The control means has a first drive mode such as a plain paper transport mode and a second drive mode which is a thick paper transport mode in which the drive source is rotated at a rotation speed slower than the first rotation speed. In the first drive mode, the driving force is transmitted to the output target rotating body via the belt drive transmission path, and in the second drive mode, the output target rotating body is transmitted via the gear drive transmission path. The drive transmission switching means is controlled so that the drive force is transmitted to the vehicle.
According to this, as described in the seventh embodiment, in the first drive mode in which the load is rapidly accelerated at the start of the drive and the load fluctuation is larger than the second drive mode, the belt drive transmission path is used. The load fluctuation at the start of driving can be absorbed by the elastic deformation of the belt. As a result, it is possible to suppress the generation of noise as compared with the case of using a gear drive transmission path in which drive transmission is performed by meshing gears. On the other hand, in the second drive mode in which the load fluctuation at the start of driving is smaller than that in the first mode, a gear drive transmission path having higher durability than the belt drive transmission path can be used. As a result, both the quietness of the device and the durability can be achieved.

(Aspect 19)
In a sheet transport device including a transport member for transporting a sheet (in this embodiment, a fixing roller 230a, a first resist roller 29a, a feed roller 27a) and a drive means for rotationally driving the transport member, as the drive means. , The driving device according to any one of aspects 11 to 18.
According to this, the size of the device can be reduced by using the drive device of the modes 11 to 17. Further, by using the drive device of the eighteenth aspect, it is possible to reduce the noise of the sheet transfer device.

(Aspect 20)
In an image forming apparatus including an image forming means for forming an image and a driving means for driving a rotating body, the driving device according to any one of aspects 11 to 18 was used as the driving means.
According to this, the size of the device can be reduced by using the drive device of the modes 11 to 17. Further, by using the drive device of the aspect 18, it is possible to reduce the noise of the device.

1: Motor 1a: Motor gear 2: Fixing idler gear 2a: First external tooth gear 2b: Second external tooth gear 3: Second input gear 3a: Second input pulley 4: One-way clutch 5: First electromagnetic clutch 5a: Drive claw 5b: Armature 5c: Rotor part 5d: Electromagnetic coil part 5e: Shaft fixing part 5f: Drive connecting 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: Bracket 8b, 8c, 8d, 8e: Bearing 9: Side plate 9a, 9b, 9c, 9d, 9e: Bearing 10: Fixing gear 11: Resist feeding input gear 12: Resist electromagnetic clutch 13: Resist gear 14 : Feeding idler gear 15: Feeding electromagnetic clutch 16: Feeding gear 18: Internal tooth gear 18a: Internal tooth 18b: External tooth 19: First idler gear 19a: First gear part 19b: Second gear part 20: Fixing device 26 : Sheet accommodating cassette 27: Separation means 27a: Feed roller 27b: Separation pad 28: Transfer roller pair 28a: First transfer roller 28b: Second transfer roller 29: Resist roller pair 29a: First resist roller 29b: Second resist roller 30: Output roller pair 31: Stack part 32: Toner bottle 33: Bottle container 41: Photoreceptor 46: Image drawing 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 61b: Second output pulley 62: Second drive transmission mechanism 71: First input pulley 72: First timing belt 73: Second timing belt 81b, 8c, 81d, 81e: Hole in bracket for fitting bearing 200: Device main body 210: Feeding device 230: Fixing roller pair 230a: Fixing roller 230b: Pressurizing roller 300: Image reading device 310: Document automatic feeding device 311: Document mounting table 320: Scanner unit 321: Fixed reading unit 322: Moving reading unit 323: Image reading sensor 330: Document Transport path 400: Paper 410: Original D: Speed switching mechanism D1: First drive transmission path D2: Second drive transmission path S1: First fixed shaft S2: Second Fixed shaft S3: Third fixed shaft T: Fixing shaft U: Output fixed shaft X: Rotating shaft X2: Output rotating shaft Y: Resist shaft Z: Feed roller shaft

Japanese Unexamined Patent Publication No. 2012-203010

Claims (20)

Of the two drive transmission paths in which the reduction ratios are different from each other and the driving force of the drive source is transmitted to the output target rotating body, the driving force is transmitted to the first drive transmission path having a small reduction ratio by the control means. In a speed switching device in which a drive transmission switching means for selectively switching and controlling a cutoff state is provided and a one-way clutch is provided in a second drive transmission path having a large reduction ratio.
The first drive transmission member that transmits the drive force to the first final drive transmission member to which the drive force is finally transmitted in the first drive transmission path, and the drive force that is finally transmitted in the second drive transmission path. A second drive transmission member that transmits the driving force to the second final drive transmission member that is coaxially arranged with the first final drive transmission member is provided coaxially.
A speed switching device, characterized in that the drive transmission switching means is arranged so as not to overlap any of a plurality of drive transmission members constituting each drive transmission path when viewed from one side in the axial direction. In the speed switching device according to claim 1,
A speed switching device, wherein each of the first drive transmission member and the second drive transmission member is an input drive transmission member to which the driving force is first transmitted in each drive transmission path. In the speed switching device according to claim 1 or 2.
A speed switching device, wherein the first drive transmission path and the second drive transmission path are gear drive transmission paths that perform drive transmission by meshing gears. In the speed switching device according to claim 1 or 2.
A speed switching device, wherein the first drive transmission path and the second drive transmission path are belt drive transmission paths that perform drive transmission using a belt. In 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 provided coaxially. In the speed switching device according to claim 5,
The drive transmission switching means and the one-way clutch are arranged 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. The force is transmitted, and the second drive transmission member has a configuration in which the drive force is transmitted via the one-way clutch.
The first final drive transmission member and the second final drive transmission member are integrally formed products.
A speed switching device characterized in that the driving force is output from the first final drive transmission member or the second final drive transmission member to the output target rotating body. In the speed switching device according to any one of claims 1 to 6.
A speed switching device characterized in that the relative reduction ratio between the first drive transmission path and the second drive transmission path is 1% or less. In the speed switching device according to any one of claims 1 to 7.
A speed switching device characterized in that the drive transmission switching means is an electromagnetic clutch . In speed switching device according to any one 請Motomeko 1 to 8,
The diameter of the bearing member provided on one side of the drive transmission switching means in the axial direction 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. , A speed switching device characterized in that it is detachably provided on a side plate that supports the shaft via the bearing member. With the drive source
In a drive device provided with a drive transmission unit that transmits the drive force of the drive source to the rotating body.
The drive transmission unit, the drive device characterized by having a speed changing device according to one item of claims 1 to 9 have shifted. In the drive device according to claim 10,
A driving device characterized by transmitting the driving force to a plurality of rotating bodies. In the drive device according to claim 11,
A first drive transmission unit that transmits the driving force to a forward / reverse rotating body that rotates forward / reverse, which is one of a plurality of rotating bodies, and a unidirectional rotating body that rotates only in one direction, which is one of a plurality of rotating bodies. Is equipped with a second drive transmission unit that transmits the driving force.
A drive device characterized in that the speed switching device is provided in a second drive transmission unit. In the drive device according to claim 12,
A driving device characterized in that the forward / reverse rotating body is a fixing roller and the one-way rotating body is a resist roller. With the drive source
A first drive transmission unit that transmits the drive force to a forward / reverse rotating body that rotates the drive force of the drive source in the forward / reverse direction.
In a drive device provided with a second drive transmission unit that transmits the driving force to a unidirectional rotating body that rotates in only one direction.
The second drive transmission unit has different reduction ratios, and the first drive transmission path having a smaller reduction ratio among the two drive transmission paths for transmitting the driving force of the drive source to the output target rotating body is controlled by the control means. A speed switching device is provided in which a drive transmission switching means for selectively switching and controlling a state in which the driving force is transmitted and a state in which the driving force is cut off is provided, and a one-way clutch is provided in a second drive transmission path having a large reduction ratio.
The first drive transmission member that transmits the drive force to the first final drive transmission member to which the drive force is finally transmitted in the first drive transmission path, and the drive force that is finally transmitted in the second drive transmission path. A second drive transmission member that transmits the driving force to the second final drive transmission member that is coaxially arranged with the first final drive transmission member is provided coaxially.
A driving device characterized in that the forward / reverse rotating body is a fixing roller and the unidirectional rotating body is a resist roller. In the drive device according to any one of claims 12 to 14.
A first drive mode in which the drive source is rotated at the first rotation speed,
It has a second drive mode in which the drive source is rotated at a rotation speed slower than the first rotation speed.
A drive device characterized in that the speed of the speed switching device is switched when the drive mode is switched. In the drive device according to any one of claims 10 to 15.
A drive device including an internal gear that meshes with an output gear portion provided on an output shaft of the drive source. In the drive device according to any one of claims 10 to 16.
It said drive source, in the axial direction, the driving device being characterized in that provided on the rotary body side than drive kinematic transmission unit. With the drive source
A state in which the reduction ratios are different from each other and the driving force is transmitted by the control means to the first drive transmission path having a smaller reduction ratio among the two drive transmission paths for transmitting the driving force of the driving source to the output target rotating body. In a drive device provided with a drive transmission switching means for selectively switching and controlling a state of switching between and a state of interruption, and a speed switching device provided with a one-way clutch in a second drive transmission path having a large reduction ratio.
One of the first drive transmission path and the second drive transmission path is a gear drive transmission path that performs drive transmission by meshing gears, and the other is a belt drive transmission path that performs drive transmission using a belt.
A first drive mode in which the drive source is rotated at the first rotation speed,
It has a second drive mode in which the drive source is rotated at a rotation speed slower than the first rotation speed.
In the first drive mode, the control means transmits the driving force to the output target rotating body via the belt drive transmission path, and in the second drive mode, the control means passes through the gear drive transmission path. The drive device is characterized in that the drive transmission switching means is controlled so that the drive force is transmitted to the output target rotating body. In a sheet transport device including a transport member for transporting a sheet and a drive means for rotationally driving the transport member.
The drive means includes a drive source and a drive transmission unit that transmits the drive force of the drive source to the rotating body.
The drive transmission unit is driven by a control means to the first drive transmission path having a smaller reduction ratio among the two drive transmission paths for transmitting the driving force of the drive source to the output target rotating body having different reduction ratios. It has a speed switching device that is provided with a drive transmission switching means that selectively switches between a state of transmitting force and a state of interrupting force, and a one-way clutch is provided in a second drive transmission path having a large reduction ratio.
The first drive transmission member that transmits the drive force to the first final drive transmission member to which the drive force is finally transmitted in the first drive transmission path, and the drive force that is finally transmitted in the second drive transmission path. A sheet transfer device characterized in that a second drive transmission member for transmitting the driving force to the second final drive transmission member coaxially arranged with the first final drive transmission member is provided coaxially. .. Image forming means for forming an image and
In an image forming apparatus including a driving means for driving a rotating body,
The drive means includes a drive source and a drive transmission unit that transmits the drive force of the drive source to the rotating body.
The drive transmission unit is driven by a control means to the first drive transmission path having a smaller reduction ratio among the two drive transmission paths for transmitting the driving force of the drive source to the output target rotating body having different reduction ratios. It has a speed switching device that is provided with a drive transmission switching means that selectively switches between a state of transmitting force and a state of interrupting force, and a one-way clutch is provided in a second drive transmission path having a large reduction ratio.
The first drive transmission member that transmits the drive force to the first final drive transmission member to which the drive force is finally transmitted in the first drive transmission path, and the drive force that is finally transmitted in the second drive transmission path. An image forming apparatus characterized in that a second drive transmission member for transmitting the driving force to the second final drive transmission member coaxially arranged with the first final drive transmission member is provided coaxially. ..

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