JP2014169723A - Gear transmission device, process unit having the same, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a gear transmission device having gear rows providing low-rotation high-torque transmission from a drive side to a driven side with space saving, at a high engagement rate, at low vibration and low noise, and at high durability and high rotation accuracy.SOLUTION: A gear transmission device has: a first rotating member 160; and a second rotating member 170. An outside cylinder part 160c is formed at the first rotating member 160 which rotates with a support shaft 150 as a center. A driven inner tooth gear part 160a is formed at an internal peripheral face of the outside cylinder part 160c. A drive outside tooth gear 140 which is rotated by a drive motor 120 is engaged with the driven inner tooth gear part 160a, and thereby the first rotating member 140 rotates. An external peripheral face of the outside cylinder part 160c is connected to the second rotating member 170 by a gear or a belt so as to be transmittable in torque.

Description

  The present invention relates to a space-saving gear transmission in which a first-stage reduction gear has a driven internal gear portion, a process unit including the gear transmission, and an image forming apparatus.

  Conventionally, in a gear transmission that drives a driven body with low rotation and high torque, a drive external gear attached to a rotation shaft of a drive motor as a drive source and a first-stage driven gear that meshes with the drive external gear are low rotation and high Designed to provide torque power transmission. That is, the drive external gear of the drive motor is set to have a small number of teeth (or pitch circle diameter) for speed increase, while the pitch circle diameter of the first stage driven gear is set to be relatively large. A large reduction ratio has been achieved.

  However, if the number of teeth of the drive external gear of the drive motor is reduced, the engagement ratio with the first-stage driven gear cannot be sufficiently obtained, which causes rotation unevenness and noise / vibration. In order to reduce the noise and vibration, measures such as injecting grease into the meshing portion of the gear are taken, but it is not sufficient. In addition, when grease is injected a plurality of times, there is a high possibility that foreign matters will be mixed into the gear meshing portion during the injection, and there is a possibility that abnormal sounds due to the foreign matters, deterioration of rotation accuracy, and damage to the gears may increase. there were.

  In order to solve such a problem, Patent Document 1 (Japanese Patent Laid-Open No. 11-311302) describes a first-stage driven gear that meshes with a drive external gear attached to a rotation shaft of a drive motor for the purpose of reducing noise and vibration. A gear transmission in which a gear is an internal gear is disclosed.

  However, since the gear transmission of Patent Document 1 (Japanese Patent Application Laid-Open No. 11-311302) has a plurality of driven-side rotation shafts arranged sequentially away from the rotation shaft of the drive motor, a plurality of different drive targets are arranged. When driving, there is a problem that a relatively large space is required.

  An object of the present invention is to provide a gear transmission that can be configured with a space-saving, high meshing rate, low vibration / low noise, high durability, and high rotational accuracy in a gear train that has low rotation and high torque transmission from the drive side to the driven side Is to provide.

  In order to solve the above-mentioned problems, the present invention has a driven inner gear having a concentric inner peripheral surface and an outer peripheral surface centering on a support shaft and meshing with a drive external gear driven by a driving means on the inner peripheral surface. A gear transmission device comprising: a first rotating member in which a tooth gear portion is formed; and a second rotating member connected to an outer peripheral surface of the first rotating member so as to transmit torque.

  In the gear transmission of the present invention, the driven internal gear portion of the first rotating member is meshed with the driving external gear portion, and the driven body is moved from the outer peripheral surface of the first rotating member located outside the driven internal gear portion. Since the driving force is transmitted, the first rotating member and the second rotating member can be disposed close to each other in a common thickness space in the axial direction, and a space-saving reduction gear train can be configured. Moreover, since the internal gear is used for the first-stage gear transmission, a high meshing rate, low vibration / low noise, high durability / high rotation accuracy can be realized.

(A) is sectional drawing of the gear transmission which concerns on 1st Embodiment of this invention, (B) is BB arrow sectional drawing of (A). It is sectional drawing of the gear transmission which concerns on 2nd Embodiment of this invention. It is sectional drawing of the gear transmission which concerns on 3rd Embodiment of this invention. It is sectional drawing of the gear transmission which concerns on 4th Embodiment of this invention. It is sectional drawing of the gear transmission which concerns on 5th Embodiment of this invention. 1 is a schematic sectional view of an image forming apparatus using a gear transmission according to an embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a gear transmission according to an embodiment of the present invention will be described with reference to the drawings. However, duplicated descriptions are appropriately omitted by assigning common reference numerals to components that are common or corresponding in the drawings.

(First embodiment)
FIG. 1 shows the gear transmission of the first embodiment. As shown in FIG. 1, the gear transmission has two vertical plate frames 100 and 110 facing each other in parallel. A drive motor 120 as a drive source is attached to the outside of the left plate frame 100 via a seat plate 130.

  The rotating shaft 120a of the drive motor 120 penetrates the seat plate 130 and the plate frame 100 in the horizontal direction and protrudes horizontally toward the right plate frame 110. A drive external gear 140 is integrally connected to the distal end side of the rotation shaft 120 a of the drive motor 120. The pitch circle of the drive external gear 140 is set to be small in order to obtain a large reduction ratio, and has substantially the same diameter as the rotating shaft 120a as shown in the figure.

  Both ends of the support shaft 150 arranged in the horizontal direction are supported in the vicinity of the drive motor 120 with respect to the two plate frames 100 and 110. The first rotating member 160 is rotatably supported on the support shaft 150. The central portion of the first rotating member 160 supported by the support shaft 150 is an inner cylindrical portion 160e in which a plurality of ribs 166 are formed in a radial shape, and a required strength is ensured with a small amount of material.

  The first rotating member 160 has a driven internal gear portion 160 a that meshes with the driving external gear 140. The driven internal gear portion 160 a is set to a pitch circle that is about 10 times larger than the drive external gear 140 in order to reduce the rotational speed of the drive external gear 140.

  A driving external gear 160 b is integrally formed on the outer peripheral surface of the first rotating member 160. The driving external gear portion 160b and the driven internal gear portion 160a are positioned on the inner peripheral surface and the outer peripheral surface of the outer cylindrical portion 160c of the first rotating member 160.

  A second rotating member 170 driven by the first rotating member 160 is disposed between the plate-like frames 100 and 110. A driven external gear portion 170a formed on the outer periphery of the second rotating member 170 meshes with the first rotating member 160 driving external gear portion 160b.

  The second rotating member 170 is integrated with a rotating shaft 200 that is rotatably supported by bearings 180 and 190 attached to the plate frames 100 and 110. The rotating shaft 200 is coaxially connected to the driven body 210. Therefore, in this gear transmission, the rotation of the drive motor 120 is such that the drive external gear 140 → the driven internal gear portion 160a of the first rotation member 160 → the drive external gear portion 160b → the driven external tooth of the second rotation member 170. It is transmitted through the path of gear part 170a → rotating shaft 200 → driven body 210.

  The first rotating member 160 and the second rotating member 170 can be formed of an appropriate material according to the application. In the case of a relatively small torque, the first rotating member 160 and the second rotating member 170 can be made of, for example, resin, and the gear meshing noise can be effectively reduced by using a resin gear.

  A circular rib 101 may be formed on the inner surface of the plate-like frame 100 so as to cover the outer edge of the outer cylindrical portion 160 c of the first rotating member 160. By providing the rib 101 in this way, it is possible to suppress the gear meshing sound generated in the annular groove 161 of the first rotating member 160 from being diffused to the outside. The rib 101 does not need to be completely continuous in a circular shape, and in order to avoid a meshing portion with the second rotating member 170 or to supply grease to the driving external gear 140 and the driven internal gear 160a, A part of the rib 101 may be cut out with an appropriate length. The rotating shaft 200 and the driven body 210 are not necessarily closest to the driving external gear 140 and can be disposed at any position in the circumferential direction of the first rotating member 160.

(Second Embodiment)
FIG. 2 shows a second embodiment of the present invention, in which the outer cylindrical portion 160c of the first rotating member 160 is cut into a concave shape by forming annular grooves 162 and 163 from the left and right sides. When the first rotating member 160 is molded with resin, the difference between the distance between the tooth tips and the distance between the tooth bottoms of the driven internal gear portion 160a and the drive external gear portion 160b is increased, and the material is thermally contracted. This makes it difficult to ensure gear accuracy. Therefore, by controlling the thickness by removing the thickness, it becomes possible to make the driven internal gear portion 160a and the drive external gear portion 160b high-precision gears. Moreover, the material cost of the 1st rotation member 160 can be reduced and weight reduction by the said meat | fleshing. When the second rotating member 170 is also molded with resin, it can be similarly cut out by forming the annular grooves 171 and 172 from the left and right sides. Others are the same as in the first embodiment.

(Third embodiment)
FIG. 3 shows a third embodiment of the present invention. The drive external gear 140, the driven internal gear portion 160a, the drive external gear portion 160b, and the driven external gear portion 170a are respectively connected to the inclined gear H. It is what. A combination of the inner and outer inclined gears H of the first rotating member 160 is configured to generate thrust forces S in opposite directions. By using the inclined gear H, vibration, noise, rotation accuracy and durability are improved. Furthermore, by generating the thrust force S in the reverse direction, the moving force in the thrust direction of the first rotating member 160 can be canceled. Thereby, friction, wear, and noise with the plate-like frame 100 or 110 due to movement of the first rotating member 160 in the thrust direction can be eliminated.

(Fourth embodiment)
FIG. 4 shows a fourth embodiment of the present invention. The outer peripheral surface of the first rotating member 160 and the outer surface of the second rotating member 170 are cylindrical surfaces 160d and 170d having appropriate friction. The belt 220 is wound around the cylindrical surfaces 160d and 170d of the rotating members 160 and 170. 1 to 3 are all gear transmission, FIG. 4 is a combination of gear transmission and belt transmission.

  In this embodiment, the space is greatly reduced as compared with the case where a single gear and a single pulley are combined in multiple stages. Further, the belt 220 facilitates long-distance transmission, and has an advantage that vibration transmission can be blocked by the belt 220. It is also possible to form a gear on the cylindrical surfaces 160d and 170d to form a timing pulley and the belt 220 to be a timing belt. The rest is the same as FIG. In the fourth embodiment as well, it goes without saying that the first rotating member 160 and the second rotating member 170 may be hollowed as shown in FIG.

(Fifth embodiment)
FIG. 5 shows a fifth embodiment of the present invention. A tapered portion 141 is formed at the distal end portion of the driving external gear 140, and tapered portions 164 and 165 are also formed at inner and outer peripheral edges of the annular groove 161 of the first rotating member 160. By forming the taper portions 141, 164, 165 in this way, the operation when the drive external gear 140 is inserted into the annular groove 161 of the first rotating member 160 and meshed with the driven internal gear portion 160a is easy. become. Further, the gear can be prevented from being damaged. Others are the same as FIG.

  Even if the taper portion 141 and the taper portions 164 and 165 are formed only on either the shaft side or the groove side, the effect that the drive external gear 140 can be smoothly inserted into the annular groove 161 is obtained. Of course, the taper portions 141, 164, 165 may be formed even in the belt transmission type of FIG.

  In the gear transmission described above, when the drive motor 120 rotates, the first rotating member 160 is rotated by the driving external gear 140 connected to the rotating shaft 120a, and the second rotating member 160 is rotated by the rotation of the first rotating member 160. 170 and driven body 210 are rotated.

  The rotational speed of the drive motor 120 is greatly reduced in the first stage transmitted from the drive external gear 140 to the driven internal gear portion 160a, and is transmitted from the drive external gear portion 160b to the driven external gear portion 170a. In two stages, acceleration or deceleration is performed according to the gear ratio. In the illustrated example, the pitch circle of the driving external gear portion 160b is made larger than the pitch circle of the driven external gear portion 170a, so that the speed is slightly increased in the second stage.

  When the rotation is transmitted, the meshing rate of the meshing portion of the driving external gear 140 and the driven internal gear 160a increases. In addition, since the meshing portion is in the annular groove 161, not only vibration and noise during rotational driving are reduced, but also the gear meshing sound is difficult to leak to the outside, and the lubricating grease is not easily scattered to the outside. Furthermore, by forming the rib 101 on the plate-like frame 100 as described above, the effect of reducing noise and preventing grease scattering can be enhanced.

Thus, in the embodiment of the present invention, the driven internal gear portion 160a of the first rotating member 160 is meshed with the drive external gear 140 driven by the drive motor 120. The drive external gear 160b on the outside of the driven internal gear 160a meshes with the driven external gear 170a of the second rotating member 170. Accordingly, the first rotating member 160 and the second rotating member 170 can be disposed close to each other within a common thickness space in the axial direction. As a result, noise can be reduced and grease scattering can be prevented, and the following effects can be obtained.
1) A thin and space-saving reduction gear train can be configured.
2) The second rotating member 170 having the driven external gear portion 170a can be easily detached from the first rotating member 160 in the axial direction, and the assembly and disassembly of the apparatus can be improved.
3) By increasing the meshing rate, the rotational accuracy and durability of the drive external gear 140 and the first rotating member 160 can be improved.
4) It is possible to reduce the possibility of foreign matter biting into the meshing portion of the driving external gear 140 and the driven internal gear portion 160a.

(Image forming device)
1 to 5 described above can be employed in various drive mechanisms. Here, an example applied to the image forming apparatus of FIG. 6 is shown. In this image forming apparatus, at least one of process units 1K, 1Y, 1M, and 1C, photosensitive drums 2K, 2Y, 2M, and 2C, an intermediate transfer belt 20, a paper feed roller 30 as a paper transport roller, and a fixing device 40. Can be driven by the aforementioned gear transmission.

  FIG. 6 is a schematic view of a laser printer. The image forming apparatus may be a copying machine, a printer, a facsimile machine, or a combination machine that combines two or more of these.

  The image forming apparatus includes four process units 1K, 1Y, 1M, and 1C as image forming units that form images with developers of black, yellow, magenta, and cyan corresponding to color separation components of a color image. . Each process unit 1K, 1Y, 1M, 1C has toner bottles 6K, 6Y, 6M, 6C containing unused toners of different colors. Other than that, the configuration is the same. The configuration of one process unit 1K will be described as an example. The process unit 1K includes a photosensitive drum 2K (photosensitive drum), a drum cleaning device 3K, a charging device 4K, a developing device 5K, and the like. The process unit 1K is detachably attached to the main body of the image forming apparatus so that consumable parts can be replaced at a time.

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

  A transfer device 8 serving as a first transfer unit is disposed below the process units 1K, 1Y, 1M, and 1C. The transfer device 8 includes four primary transfer rollers 9K, 9Y, 9M, and 9C facing each of the photosensitive drums 2K, 2Y, 2M, and 2C, each primary transfer roller 9K, 9Y, 9M, and 9C, a driving roller 21, and a driven roller. 22, an intermediate transfer belt 20 that circulates in a circulating manner, a secondary transfer roller 23 as a second transfer portion disposed opposite to the driving roller 21, a belt cleaning device 10, and the like. If the photoreceptor drums 2K, 2Y, 2M, and 2C are the first photoreceptors of the respective colors, the intermediate transfer belt 20 is a second photoreceptor that combines these images.

  In the lower part of the image forming apparatus, a paper feed tray 50 capable of storing a large number of sheets P and a paper feed roller 30 for sending the paper P from the paper feed tray 50 toward the paper feed path 31 are provided. Near the end of the paper feed path 31, a timing roller pair 56 for temporarily stopping the paper P is provided.

  This pair of timing rollers 56 is positioned immediately upstream of the intermediate transfer belt 20 and once sags the paper P in order to accurately align the toner image on the intermediate transfer belt 20 and the front end position of the paper. Then, immediately before the toner image formed on the intermediate transfer belt 20 is transferred to the paper P at the secondary transfer nip portion, the paper P is sent to the secondary transfer nip portion at a predetermined timing.

  A post-transfer conveyance path 32 is disposed above the nip portion between the secondary transfer roller 23 and the drive roller 21. A fixing device 40 as a fixing unit is provided near the end of the post-transfer conveyance path 32. The fixing device 40 includes a fixing roller 40a including a heat source such as a halogen lamp (not shown), and a pressure roller 40b that rotates while contacting the fixing roller 40a with a predetermined pressure.

  A post-fixing conveyance path 41 is disposed above the fixing device 40, and branches to a paper discharge path 42 and a reverse conveyance path 43 at the end of the post-fixing conveyance path 41. A switching member 44 that swings around a swing shaft 44a is disposed on the side of the post-fixing conveyance path 41. A paper discharge roller pair 45 is disposed at the end of the paper discharge path 42. The reverse conveyance path 43 joins the paper feed path 31 at the end thereof, and a reverse conveyance roller pair 46 is disposed in the middle of the reverse conveyance path 43. A paper discharge tray 47 having an upper cover recessed inward is disposed at the top of the image forming apparatus.

  A powder container 60 (toner container) for storing waste toner is disposed between the transfer device 8 and the paper feed tray 50. The powder container 60 is detachably attached to the image forming apparatus main body.

(Operation of image forming apparatus)
Next, the basic operation of this image forming apparatus will be described. In FIG. 3, when the paper feed roller 30 is rotated by a paper feed signal from a control unit of an image forming apparatus (not shown), only the topmost paper P stacked on the paper feed tray 50 is separated, and the paper feed path 31. Sent out. When the leading edge of the paper P reaches the nip portion of the timing roller pair 56, the timing is synchronized (synchronized) with the toner image formed on the intermediate transfer belt 20, and the paper P is slackened to correct the leading edge skew of the paper P. Wait in the state of forming.

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

  The developing roller of the developing device 5K transfers toner to the surface portion of the photosensitive drum 2K on which the electrostatic latent image is formed, thereby forming (developing) a black toner image. Then, the toner image formed on the photosensitive drum 2K is transferred to the intermediate transfer belt 20.

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

  In the process units 1Y, 1M, and 1C for the respective colors, toner images are similarly formed on the photosensitive drums 2Y, 2M, and 2C, and transferred to the intermediate transfer belt 20 so that the respective color toner images are overlapped.

  When the color toner images are transferred to the intermediate transfer belt 20 so as to overlap, the timing roller pair 56 and the paper feed roller 30 start to drive, and take timing (synchronization) with the toner image superimposed and transferred to the intermediate transfer belt 20. The paper P is sent to the secondary transfer roller 23. Then, the toner image on the intermediate transfer belt 20 is transferred to the fed paper P by the secondary transfer nip portion of the secondary transfer roller 23.

  The paper P to which the toner image has been transferred is conveyed to the fixing device 40 through the post-transfer conveyance path 32. The paper P sent to the fixing device 40 is sandwiched between the fixing roller 40a and the pressure roller 40b, and the unfixed toner image is heated and pressed to be fixed on the paper P. The paper P on which the toner image is fixed is sent out from the fixing device 40 to the post-fixing conveyance path 41.

  At the timing when the paper P is sent out from the fixing device 40, the switching member 44 is in the position indicated by the solid line in FIG. 3 and opens near the end of the post-fixing conveyance path 41. The paper P sent out from the fixing device 40 passes through the post-fixing conveyance path 41, is sandwiched between the paper discharge roller pair 45, and is discharged to the paper discharge tray 47.

  When performing duplex printing, when the trailing edge of the paper P conveyed by the paper discharge roller pair 45 passes through the post-fixing conveyance path 41, the switching member 44 swings to the position indicated by the dotted line in FIG. The vicinity of the end of the path 41 is closed. At substantially the same time, the paper discharge roller pair 45 rotates in the reverse direction, and the paper P is fed back and enters the reverse conveyance path 43.

  The sheet P transported in the reverse transport path 43 passes through the reverse transport roller pair 46, reaches the timing roller pair 56, and is sent out in time with the toner image for the back surface formed on the intermediate transfer belt 20. Then, the toner image is transferred to the back surface of the paper P when passing through the secondary transfer roller 23. After the toner image on the back surface of the paper P is fixed by the fixing device 40, the paper P is discharged to the paper discharge tray 47 through the post-fixing conveyance path 41, the paper discharge path 42, and the paper discharge roller pair 45 in order.

  Further, after the toner image on the intermediate transfer belt 20 is transferred to the paper P, residual toner is adhered on the intermediate transfer belt 20. This residual toner is removed from the intermediate transfer belt 20 by the belt cleaning device 10. The toner removed from the intermediate transfer belt 20 is collected in the powder container 60 by a waste toner transport unit (not shown).

  The gear transmission device, the process unit, and the image forming apparatus as the embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made.

1K, 1Y, 1M, 1C: process units 2K, 2Y, 2M, 2C: photosensitive drums 3K, 3Y, 3M, 3C: drum cleaning devices 4K, 4Y, 4M, 4C: charging devices 5K, 5Y, 5M, 5C: Developing devices 6K, 6Y, 6M, 6C: toner bottle 7: exposure device 8: transfer devices 9K, 9Y, 9M, 9C: primary transfer roller 10: belt cleaning device 20: intermediate transfer belt 21: drive roller 22: driven roller 23 : Secondary transfer roller 30: paper feed roller 31: paper feed path 32: post-transfer conveyance path 40: fixing device 40 a: fixing roller 40 b: pressure roller 41: post-fixation conveyance path 42: paper discharge path 43: reverse conveyance path 44: switching member 44a: swinging shaft 45: paper discharge roller pair 46: reverse conveying roller pair 47: paper discharge tray 50: paper feed tray 56: timing roller pair 60: powder container 1 0, 110: plate-like frame 101: rib 120: drive motor 120a: rotating shaft 130: seat plate 140: driving external gear 141: taper portion 150: support shaft 160: first rotating member 160a: driven internal gear portion 160b : Drive external gear portion 160c: Outer cylindrical portion 160d: Cylindrical surface 161: Annular groove 162, 163: Annular groove (thickening)
164, 165: Tapered portion 170: Second rotating member 170a: Driven external gear portion 171, 172: Annular groove (thickening)
180, 190: bearing 200: rotating shaft 210: driven body 220: belt H: inclined gear L: laser beam P: paper

Japanese Patent Laid-Open No. 11-311302

Claims (11)

A first rotating member having a concentric inner peripheral surface and an outer peripheral surface with a support shaft as a center, and a driven internal gear portion meshing with a driving external gear driven by a driving means is formed on the inner peripheral surface. When,
A gear transmission comprising: a second rotating member coupled to an outer peripheral surface of the first rotating member so as to be able to transmit torque.   2. The gear transmission according to claim 1, wherein both ends of the support shaft are supported by frames, and the first rotating member and the second rotating member are disposed between the frames.   The gear transmission according to claim 1, wherein an inner cylindrical portion having a plurality of ribs formed radially is formed around the support shaft of the first rotating member.   The gear according to claim 1, wherein a driving external gear portion is formed on an outer peripheral surface of the first rotating member, and the second rotating member has a driven external gear portion meshing with the driving external gear portion. Transmission device.   5. The gear transmission according to claim 4, wherein the driven internal gear portion and the drive external gear portion are constituted by bevel gears inclined so as to generate thrust forces in opposite directions.   The gear transmission according to claim 1, wherein a belt is wound around an outer peripheral surface of the first rotating member and an outer peripheral surface of the second rotating member.   The gear transmission according to any one of claims 1 to 6, wherein at least one of the first rotating member and the second rotating member is hollowed in a concave shape.   The gear transmission according to any one of claims 1 to 7, wherein a tapered portion is formed at each of a front end portion of the driving external gear and an end edge of the driven internal gear portion.   2. The image forming apparatus according to claim 1, wherein one of a photosensitive drum, an intermediate transfer belt, a fixing device, and a sheet conveying roller of the image forming apparatus is connected to the second rotating member as a driven body. The gear transmission device according to any one of 8.   A gear transmission device according to any one of claims 1 to 8, comprising at least one of a photosensitive drum, a developing roller, and a paper transporting roller as a driven member connected to the second rotating member of the gear transmission device. A process unit characterized by   An image forming apparatus comprising the gear transmission device according to claim 9 or the process unit according to claim 9.

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