Rotating device and image forming device

Abstract

To provide a rotary device which can inhibit occurrence of abnormal noise, and to provide an image formation device.SOLUTION: A paper discharge drive device, such as a rotary device, has: a shaft member such as a first support shaft 115; a mating member, such as a first relay pulley 105, having a shaft insertion part into which the shaft member is inserted; bearings, such as ball bearings 141, 142, which are disposed between the mating member and the shaft member, enable relative rotation therebetween, and are provided in the shaft insertion part; and a removal prevention member, such as an E ring 113, attached to one axial end part of the shaft member. The mating member has a facing part 105e which is located at one side relative to the bearings and faces the removal prevention member from an axial direction.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a rotation device and an image forming apparatus. [Background technology]

[0002] Conventionally, a rotating device has been known that includes a shaft member, a mating member having a shaft insertion portion into which the shaft member is inserted, a bearing provided in the shaft insertion portion that is interposed between the mating member and the shaft member and enables them to rotate relative to each other, and a retaining member attached to one axial end of the shaft member.

[0003] Patent Document 1 describes a rotating device in which one axial side of a paddle shaft serving as a shaft member is rotatably supported by a ball bearing serving as a mating member, a bearing case. An E-ring groove is provided on the paddle shaft on one axial side of the ball bearing, and an E-ring serving as a retaining member is attached to this E-ring groove so as to contact the one axial end of the ball bearing. Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a risk of abnormal noise being generated. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a rotating device comprising: a shaft member; a mating member having a shaft insertion portion into which the shaft member is inserted; two bearings having different inner ring inside diameters and arranged approximately coaxially within the shaft insertion portion, the bearing having the shorter inner ring inside diameter being interposed between the mating member and the shaft member and allowing them to rotate relatively; and a retaining member attached to one end of the shaft member in the axial direction, wherein the bearing having the shorter inner ring inside diameter of the two bearings is arranged on the one side of the shaft member, the mating member rotates integrally with the outer rings of the two bearings, and has an opposing portion that is arranged in the axial direction between the retaining member and the bearing having the shorter inner ring inside diameter, the retaining member can come into contact with the opposing portion but cannot come into contact with the bearing having the shorter inner ring inside diameter, and the two bearings are the side on which the facing portion is not provided It is characterized in that it is configured to be attachable only from the [Effects of the Invention]

[0006] According to the present invention, the generation of abnormal noise can be suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a copying machine according to an embodiment. [Figure 2] FIG. [Figure 3] FIG. 3 is a schematic configuration diagram of the paper discharge drive device as seen from the direction A in FIG. 2. [Figure 4] FIG. 10 is a schematic diagram of a conventional first relay pulley. [Figure 5] FIG. [Figure 6] FIG. 3 is a schematic diagram of a first ball bearing. [Figure 7] FIG. 4 is a diagram showing the inner diameter dimension of the outer ring of the first ball bearing. [Figure 8] 10 is a diagram showing a configuration in which an E-ring contacts the outer ring of a first ball bearing. FIG. [Figure 9]FIG. 3 is a schematic configuration diagram showing a first relay pulley, a first support shaft, and an E-ring in the embodiment. [Figure 10] FIG. 4 is a perspective view showing a first intermediate pulley, a first support shaft, and an E-ring in the embodiment. [Figure 11] FIG. 10 is a perspective view illustrating assembly of the first ball bearing and the second ball bearing to the first intermediate pulley. [Figure 12] 10 is a cross-sectional view illustrating the assembly of the first ball bearing and the second ball bearing to the first intermediate pulley. FIG. [Figure 13] FIG. 10 is a perspective view illustrating the assembly of the first intermediate pulley, to which the ball bearings are assembled, onto the first support shaft. [Figure 14] FIG. 10 is a schematic configuration diagram of a first modified example. [Figure 15] 10A and 10B are diagrams illustrating the assembly of a first intermediate pulley in Modification 1. [Figure 16] FIG. 10 is a schematic configuration diagram of a second modified example. [Figure 17] FIG. 10 is a schematic configuration diagram of a third modified example. [Figure 18] FIG. 10 is a schematic configuration diagram of a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment in which the present invention is applied to a copier as an image forming apparatus will be described below. First, an overview of this copier will be described using Figure 1. This copier functions as a so-called digital color copier, which scans and reads an original, digitizes the image information obtained, and uses it to form an image. This copier also has a facsimile function for sending and receiving image information from an original to a remote location, and a printer function for printing image information handled by a computer onto paper.

[0009] In FIG. 1, the copier is a tandem-type electrophotographic device that forms images on recording sheets by an intermediate transfer method using an intermediate transfer belt 11, and that creates each color toner image using a dedicated process cartridge. A multi-tiered feed unit 2 is provided at the bottom vertically of the copier. Also provided above that is an image forming unit 1, and a scanner unit 3 below that. Each tier of the feed unit 2 is provided with a feed tray 21 that stores a stack of recording sheets, such as plain paper, overhead projector sheets, and secondary masters, and a feed device 21a that feeds the sheets stored in the sheet stack in the feed tray 21. The feed device 21a includes a pickup roller 21a1 that feeds recording sheets from the feed tray 21, and a separation / feeding means 21a2 that separates and feeds the sheets that have been fed.

[0010] Near the center of the image forming unit 1, there is disposed a transfer device 10, which has an endless intermediate transfer belt 11 stretched around multiple rollers arranged inside a belt loop. The intermediate transfer belt 11 rotates (surface moves) clockwise in the drawing. Four process cartridges 40Y, 40M, 40C, and 40K for forming yellow, magenta, cyan, and black toner images are disposed above the intermediate transfer belt 11 along the surface movement direction of the intermediate transfer belt 11. Hereinafter, the color codes Y, M, C, and K will be omitted as appropriate. In addition, above the four process cartridges 40, there are disposed two latent image writing means, a first writing unit 20a and a second writing unit 20b.

[0011] Each process cartridge 40 is provided with a drum-shaped photosensitive member 41 as a latent image carrier. Each photosensitive member 41 is provided so as to be rotatable counterclockwise in the drawing, and is surrounded by a known charging device, developing device, photosensitive member cleaning device, and lubricant application device.

[0012] The transfer device 10 includes an intermediate transfer belt 11, a belt cleaning device 17, and four primary transfer rollers 46. The intermediate transfer belt 11 is tensioned by a plurality of rollers including a tension roller 14, a drive roller 15, and a secondary transfer opposing roller 16. A belt drive motor rotates and drives the drive roller 15, causing the intermediate transfer belt 11 to move endlessly in a clockwise direction in the drawing.

[0013] Each of the four primary transfer rollers 46 is disposed so as to contact the inner circumferential surface of the intermediate transfer belt 11, and receives a primary transfer bias from a power source. The four primary transfer rollers 46 press the intermediate transfer belt 11 from its inner circumferential surface toward the photosensitive member 41, thereby forming a primary transfer nip. The primary transfer rollers form a primary transfer electric field between the photosensitive member and the primary transfer roller at each primary transfer nip by the primary transfer bias. The primary transfer rollers perform primary transfer of the toner image on the photosensitive member 41 onto the intermediate transfer belt 11 due to the influence of this primary transfer electric field and nip pressure.

[0014] The transfer device 10 also has a secondary transfer unit 22 below the intermediate transfer belt 11, which constitutes a secondary transfer means. The secondary transfer unit 22 has a secondary transfer roller 22a that is in pressure contact with the secondary transfer opposing roller 16 via the intermediate transfer belt 11. The secondary transfer roller 22a then performs a collective secondary transfer of the toner image on the intermediate transfer belt 11 onto a recording sheet fed between the secondary transfer roller 22a and the intermediate transfer belt 11. A belt cleaning device 17 is provided downstream of the secondary transfer opposing roller 16 in the direction of movement of the surface of the intermediate transfer belt 11. The belt cleaning device 17 removes residual toner remaining on the surface of the intermediate transfer belt 11 after image transfer. The belt cleaning device 17 also has a lubricant application mechanism. The lubricant application mechanism applies a lubricant to the surface of the intermediate transfer belt 11.

[0015] A fixing device 25 is provided downstream of the secondary transfer roller 22a in the paper transport direction, which fixes the toner image formed on the recording sheet to the surface of the sheet. An endless fixing belt 26 is in pressure contact with a fixing pressure roller 27. An endless conveyor belt 24 is provided between a pair of rollers between the secondary transfer unit 22 and the fixing device 25. The conveyor belt 24 conveys the recording sheet to the fixing device 25 after the image has been transferred. In addition, a reversing conveyor device 28 is provided below the secondary transfer roller 22a, which conveys the sheet that has been reversed when images are formed on both sides of the sheet.

[0016] Also, a manual feed unit 4 is provided on the right side of the image forming unit 1 in the drawing. The manual feed unit 4 has a manual feed tray 51 on which manually fed recording sheets are placed, and a manual feed device 150 that feeds the recording sheets placed on the manual feed tray 51. The manual feed device 150 has a manual feed pickup roller 52 that feeds recording sheets from the manual feed tray 51, a manual feed separation and feeding means 53 that separates and feeds the fed sheets, and the like.

[0017] When a copier having the above configuration copies a color original, the copier reads the image of the original placed on the contact glass using the scanner unit 3. The copier also rotates the intermediate transfer belt 11 and forms a toner image on each photoconductor 41 using a known image formation process. Next, the copier performs primary transfer onto the intermediate transfer belt 11, superimposing the toner images formed on each photoconductor in order, thereby forming a four-color superimposed toner image on the intermediate transfer belt 11.

[0018] Meanwhile, in parallel with the image forming operation of the four-color superimposed toner image on the intermediate transfer belt 11, the feeding device 21a separates and feeds recording sheets one by one from the selected feeding tray 21 of the feeding section 2 and transports them toward the registration rollers 29.

[0019] Instead of feeding from the feeding tray 21, feeding may be performed from the manual feed tray 51. In this case, the manual feed device 150 separates and feeds the recording sheets on the manual feed tray 51 one by one, and conveys them toward the registration rollers 29.

[0020] The registration rollers 29 abut the separated and conveyed recording sheet against a nip, temporarily stopping the conveyance and making the recording sheet wait. The registration rollers 29 start rotating at the right time so that the four-color superimposed toner image formed on the intermediate transfer belt 11 and the leading edge of the recording sheet are positioned at a predetermined position. The registration rollers 29 rotate to feed the waiting recording sheet again. The secondary transfer roller 22a performs a second transfer of the four-color superimposed toner image on the intermediate transfer belt 11 to a predetermined position on the recording sheet, forming a full-color toner image on the recording sheet.

[0021] The conveyor belt 24 sends the recording sheet on which the full-color toner image has been formed in this way to a fixing device 25 located downstream of the secondary transfer roller 22a on the conveyance path. The fixing device 25 fixes the full-color toner image secondarily transferred by the secondary transfer roller 22a onto the recording sheet.

[0022] In a face-up mode in which the recording sheet is discharged with the image formed on the side facing up, the recording sheet on which the full-color toner image has been fixed is conveyed by the pair of pre-discharge rollers 31, and is discharged outside the device by the pair of discharge rollers 30. On the other hand, in a face-down mode in which the recording sheet is discharged with the image formed on the side facing up, the recording sheet on which the full-color toner image has been fixed is conveyed to a switchback conveying device 33. The switchback conveying device 33 switchback-conveys the recording sheet toward the pair of switchback pre-discharge rollers 32, and the pair of switchback pre-discharge rollers 32 conveys the recording sheet toward the pair of discharge rollers 30. The pair of discharge rollers 30 then discharges the recording sheet outside the device.

[0023] In a double-sided print mode in which images are formed on both sides of a recording sheet, when a recording sheet with a full-color toner image fixed only on its first side is discharged from the fixing device 25, the recording sheet is sent to the switchback conveying device 33 instead of the pair of paper discharge rollers 30. The switchback conveying device 33 conveys the recording sheet in a switchback manner, inverts the sheet, and conveys it to the reversing conveying device 28. The reversing conveying device 28 reconveys the recording sheet to the registration rollers 29. Thereafter, the image forming apparatus passes the recording sheet through the secondary transfer roller 22a and the fixing device 25, and forms a full-color image on the second side as well.

[0024] Fig. 2 is a schematic perspective view of the paper discharge drive device 100 as a rotation device that drives the paper discharge roller pair 30, the paper pre-discharge roller pair 31, and the switchback paper pre-discharge roller pair 32, and Fig. 3 is a schematic configuration diagram of the paper discharge drive device 100 as seen from direction A in Fig. 2. Note that in Fig. 3, the arrangement of the components of the paper discharge drive device 100 is slightly different from that in Fig. 2 to make it easier to understand.

[0025] The drive roller 130 of the pair of discharge rollers 30 has two roller portions 130a and a roller shaft 130b. The two roller portions 130a are fixed to the roller shaft 130b with a predetermined axial distance between them. The drive roller 131 of the pair of pre-discharge rollers 31 has the same configuration as the drive roller 130 of the pair of discharge rollers 30. That is, it has two roller portions 131a and a roller shaft 131b. The drive roller 132 of the pair of switchback pre-discharge rollers 32 also has the same configuration, having two roller portions 132a and a roller shaft 132b. The front plate 1b and the rear plate 1a support the roller shafts 130b, 131b, and 131c of the drive rollers via bearings 120, 121, and 122, respectively.

[0026] The paper discharge drive device 100 is provided at the rear side of the device, which is one side in the axial direction, and has a paper discharge motor 101 as a drive source. The paper discharge motor 101 is attached to the rear side plate 1a of the device via a stud 101b. The paper discharge drive device 100 has a reduction gear 102 that meshes with a motor gear 101a of the paper discharge motor 101. The reduction gear 102 is fixed to the rear end of a roller shaft 131b of a drive roller 131 of the switchback front paper discharge roller pair 32.

[0027] The paper discharge drive device 100 includes a first timing belt 108. The first timing belt 108 is wound around the drive pulley 103, an input pulley portion 105a of the first relay pulley 105, and a second relay pulley 107. The paper discharge drive device 100 also includes a tight narrow roller 104. The tight narrow roller 104 abuts against the outer peripheral surface of the first timing belt 108 to apply tension to the first timing belt 108.

[0028] The tight narrow roller 104 is rotatably supported by a tight narrow roller support shaft 104a fixed to the rear side plate 1a. The tight narrow roller support shaft 104a is supported by a tight narrow roller holder 104b. The tight narrow roller holder 104b is held by the rear side plate 1b so that the tight narrow roller 104 can move toward and away from the first timing belt 108. The tight narrow roller holder 104b is biased toward the first timing belt 108 by a spring 104c serving as a biasing means. The spring 104c biases the tight narrow roller 104b toward the first timing belt 108, so that the tight narrow roller 104 applies a predetermined tension to the first timing belt 108.

[0029] The drive pulley 103 is fixed to the roller shaft 131b of the drive roller 131 of the front discharge roller pair 31. The first relay pulley 105 is rotatably supported on a first support shaft 115 fixed to the rear side plate 1a. The first relay pulley 105 has an input pulley portion 105a and an output pulley portion 105b. A first timing belt 108 is wound around the input pulley portion 105a. A second timing belt 116 is wound around the output pulley portion 105b. An E-ring 113 is attached to the tip of the first support shaft 115 as a retaining member. By attaching the E-ring 113 to the tip of the first support shaft 115, it is possible to prevent the first relay pulley 105 from coming off the first support shaft 115.

[0030] The second timing belt 116 has a narrower belt width than the first timing belt 108. The second timing belt 116 is wound around the first relay pulley 105 and the paper discharge output pulley 106. The paper discharge output pulley 106 is fixed to the rear end of the roller shaft 130b of the drive roller 130 of the paper discharge roller pair 30. An E-ring 114 serving as a retaining member is fixed to the rear end of the roller shaft 130b of the drive roller 130 of the paper discharge roller pair 30. This E-ring 114 prevents the paper discharge output pulley 106 from coming off the roller shaft 130b.

[0031] The second relay pulley 107, around which the first timing belt 108 is wound, is rotatably supported by a second support shaft 117 fixed to the rear side plate 1a. The second relay pulley 107 is an integrally molded resin product together with a relay gear 109 that meshes with a paper discharge output gear 110. An E-ring 112 serving as a retaining member is attached to the tip of the second support shaft 117. This E-ring 112 prevents the integrally molded product consisting of the second relay pulley 107 and the relay gear 109 from coming off the second support shaft 117.

[0032] The paper discharge output gear 110 is fixed to the rear end of the roller shaft 132b of the drive roller 132 of the switchback front discharge roller pair 32. An E-ring 111 serving as a retaining member is fixed to the rear end of the roller shaft 132b of the drive roller 132 of the switchback front discharge roller pair 32. This E-ring 111 prevents the paper discharge output gear 110 from coming off the roller shaft 130b.

[0033] The driving force of the paper discharge motor 101 is transmitted from the motor gear 101a to the reduction gear 102, thereby driving and rotating the drive roller 131 of the pair of pre-discharge rollers 31. The driving force of the paper discharge motor 101 is also transmitted to a drive pulley 103 arranged coaxially with the reduction gear 102 and to a first relay pulley 105 via a first timing belt 108. The driving force transmitted to the first relay pulley 105 is then transmitted to a paper discharge output pulley 106 via a second timing belt 116. This drives and rotates the drive roller 130 of the pair of paper discharge rollers 30. The driving force of the paper discharge motor 101 is also transmitted to a second relay pulley 107 via the first timing belt 108 and to a paper discharge output gear 110 via a relay gear 109. This drives and rotates the drive roller 132 of the pair of switchback pre-discharge rollers 32.

[0034] The first timing belt 108 is subjected to three load torques: the pair of discharge rollers 30, the pair of pre-discharge rollers 31, and the pair of switchback pre-discharge rollers 32. On the other hand, the second timing belt 116 is subjected to only the load torque of the pair of discharge rollers 30. As described above, the first timing belt 108 is subjected to a larger load torque than the second timing belt 116, so the belt width of the first timing belt 108 is made wider than the belt width of the second timing belt 116. Furthermore, by making the belt width of the second timing belt 116 narrower than the belt width of the first timing belt 108, it is possible to prevent the total axial length of the discharge drive device 100 from becoming longer.

[0035] FIG. 4 is a schematic diagram of a conventional first relay pulley 105A. As shown in FIG. 4, the first intermediate pulley 105A has a first anti-skid protrusion 105c provided between the input pulley portion 105a and the output pulley portion 105b. The first anti-skid protrusion 105c prevents the first timing belt 108 from shifting. The first intermediate pulley 105A also has a second anti-skid protrusion 105d provided at the rear end portion, which is on one axial side. The second anti-skid protrusion 105d prevents the second timing belt 116 from shifting. The first timing belt 108, which has a wider belt width than the second timing belt 116, is wound around the input pulley portion 105a. Therefore, the axial length of the input pulley portion 105a is longer than the axial length of the output pulley portion 105b.

[0036] The first relay pulley 105A has an input pulley portion 105a and an output pulley portion 105b that have different axial lengths, and has a structure in which a first slip prevention protrusion 105c is provided between the input pulley portion 105a and the output pulley portion 105b. Therefore, if the first relay pulley 105 is assembled to the first support shaft 115 in reverse, the first timing belt 108 and the second timing belt 116 cannot be wound around the first relay pulley 105A. Note that reverse assembly refers to assembly in which the first relay pulley 105A is assembled in the reverse direction relative to the normal assembly in which the output pulley portion 105b is located in front.

[0037] For this reason, conventionally, the reverse installation of the first relay pulley 105A has been prevented by a configuration as shown in FIG. 4(b). Specifically, the first support shaft 115 is provided with a first small diameter portion 115a and a second small diameter portion 115b. Furthermore, the shaft insertion portion 105g of the first relay pulley 105A is provided with a first inner circumferential surface 105h and a second inner circumferential surface 105i. The first inner circumferential surface 105h contacts the outer circumferential surface of the first small diameter portion 115a, and the second inner circumferential surface 105i contacts the outer circumferential surface of the second small diameter portion 115b. With this configuration, if an attempt is made to insert the first relay pulley 105A backward onto the first support shaft 115, the downstream end of the second inner circumferential surface 105i in the insertion direction abuts against the downstream end of the first small diameter portion 115a in the insertion direction. This prevents the first relay pulley 105A from being assembled to the first support shaft 115, thereby preventing reverse installation.

[0038] When the conventional first relay pulley 105A shown in FIG. 4 receives the driving force of the paper discharge motor 101 and rotates, the first inner circumferential surface 105h and the second inner circumferential surface 105i slide against the first support shaft 115. The first relay pulley 105A is made of resin and may wear out depending on the operating conditions. Therefore, depending on the operating conditions, such as the load on the first relay pulley 105A, the amount of wear on the first inner circumferential surface 105h and the second inner circumferential surface 105i due to sliding with the first support shaft 115 increases. This may result in the end of the life of the first relay pulley 105A prematurely. Furthermore, the sliding resistance between the first support shaft 115 and the first relay pulley 105A applies a load to the first timing belt 108 and other components. This may shorten the life of the drive transmission components, such as the first timing belt 108, of the paper discharge drive device 100.

[0039] FIG. 5 is a diagram showing another conventional example in which the conventional first intermediate pulley 105A of FIG. 4 is improved. In order to improve the problem of the configuration shown in FIG. 4, another conventional example shown in FIG. 5 has the following configuration. Specifically, a first ball bearing 141 serving as a bearing is press-fitted into the rear end (left side in the figure) of the shaft insertion portion 105g of the first intermediate pulley 105B, and a second ball bearing 142 serving as a bearing is press-fitted into the front end (left side in the figure) of the shaft insertion portion 105g of the first intermediate pulley 105B. Furthermore, the first ball bearing 141 is smaller in size than the second ball bearing 142, and its inner diameter is shorter than that of the second ball bearing 142. By making the inner diameter of the first ball bearing 141 shorter than that of the second ball bearing 142 in this way, when the first intermediate pulley 105B is assembled in the reverse direction to the first support shaft 115, the first ball bearing 141 will abut against the end of the first small diameter portion 115a. This prevents the first intermediate pulley 105B from being assembled to the first support shaft 115, and also prevents the first intermediate pulley 105B from being mounted in reverse, as in other conventional examples.

[0040] In another conventional example, the first support shaft 115, which is a shaft member, rotatably supports the first relay pulley 105B, which is a mating member, via ball bearings 141 and 142. As a result, the first relay pulley 105B is driven to rotate without sliding on the first support shaft 115. This reduces wear on the first relay pulley 105B, thereby increasing the durability of the first relay pulley 105B. Furthermore, no sliding resistance occurs between the first relay pulley 105B and the first support shaft 115. Therefore, compared to the conventional example shown in FIG. 4, the load on the drive transmission members, such as the first timing belt 108 of the paper discharge drive device 100, can be reduced.

[0041] FIG. 6 is a schematic diagram of the first ball bearing 141. As shown in FIG. 6, first ball bearing 141 has inner ring 141a made of metal, outer ring 141b made of metal, and balls 141c as rolling elements disposed between inner ring 141a and outer ring 141b. Second ball bearing 142 has the same configuration as first ball bearing 141.

[0042] The outer ring 141b of the first ball bearing 141 rotates together with the first intermediate pulley 105B. On the other hand, the static friction force between the inner ring 141a and the first support shaft 115 exceeds the friction force between the inner ring 141a and the balls 141c, and the inner ring 141a and the first support shaft 115 are stationary.

[0043] The E-ring 113, which serves as a retaining member attached to the tip of the first support shaft 115, is made of metal, and preferably contacts only the inner ring 141a of the first ball bearing 141. Therefore, as shown in FIG. 7, the outer diameter of the E-ring 113 is preferably shorter than the inner diameter L of the outer ring 141b. This is because the outer ring 141b rotates with the first intermediate pulley 105, but the E-ring 113 attached to the first support shaft 115 does not rotate. Therefore, as shown in FIG. 8, if the E-ring 113 is configured to contact the outer ring 141b, the E-ring 113 will slide on the outer ring 141b. Because the E-ring 113 and the outer ring 141b are both made of metal, sliding of the E-ring 113 on the outer ring 141b is metal-on-metal sliding, which may generate abnormal noise. Furthermore, if the metals do not slide against each other, they may seize and stick together depending on the usage conditions.

[0044] As described above, in order to prevent reverse installation of first relay pulley 105B, first ball bearing 141 is a smaller ball bearing than second ball bearing 142. In order to prevent contact with the outer ring of this small-sized first ball bearing 141, it becomes necessary to use an E-ring 113 that is smaller than the general size.

[0045] As shown in FIG. 3, in the paper discharge drive device 100, E-rings 111 are attached not only to the first support shaft 115 but also to the second support shaft 117, the roller shaft 130b of the drive roller 130 of the paper discharge roller pair 30, and the roller shaft 132b of the drive roller 132 of the switchback pre-paper discharge roller pair 32.

[0046] The E-ring 111 attached to the roller shaft 132b of the drive roller 132 rotates together with the paper discharge output gear 110. Therefore, even if the E-ring 111 is configured to contact the paper discharge output gear 110, the E-ring 111 does not slide on the paper discharge output gear 110. Therefore, there are no particular restrictions on the E-ring 111 attached to the roller shaft 132b of the drive roller 132 of the switchback pre-discharge roller pair 32, and an inexpensive E-ring of a general size can be used.

[0047] Similarly, the E-ring 114 attached to the roller shaft 130b of the drive roller 130 of the paper discharge roller pair 30 rotates together with the paper discharge output pulley 106 and does not slide on the paper discharge output pulley 106. Therefore, the E-ring 114 attached to the roller shaft 130b of the drive roller 130 of the paper discharge roller pair 30 can also be a standard size E-ring.

[0048] The E-ring 112 fixed to the second support shaft 117 fixed to the rear side plate 1a slides on the relay gear 109 that faces the E-ring 112 in the axial direction. However, the relay gear 109 is made of a resin with slidability, such as POM. Therefore, no abnormal noise is generated even when the E-ring 112 slides on the relay gear 109. Therefore, there are no particular restrictions on the E-ring 112 attached to the second support shaft 117.

[0049] As described above, in another conventional example, of the four E-rings 111, 112, 113, and 114 used in the paper discharge drive device 100, three of them (the E-rings 111, 112, and 114) can be made of inexpensive, standard-sized E-rings. However, the E-ring 113 fixed to the first support shaft 115 must be smaller than the other E-rings 111, 112, and 114. As a result, it becomes necessary to manage two E-rings: the E-ring 113 fixed to the first support shaft 115 and the other E-rings 111, 112, and 114. This may result in increased parts management costs.

[0050] In other conventional examples, there is a risk of incorrect assembly of the E-rings, such as fixing other E-rings 111, 112, and 114 to the first support shaft 115. To prevent this, it is necessary to check the size of the E-ring before attaching it to the shaft, which can result in a decrease in assembly efficiency.

[0051] In other conventional examples, it is also conceivable to make the other E-rings 111, 112, and 114 small in size, similar to the E-ring 113 fixed to the first support shaft 115. However, making them small in size may make them less easy to assemble onto the shaft, which may reduce assembly efficiency.

[0052] The paper discharge drive device 100 of this embodiment is an improvement over the other conventional examples described above. Specifically, even if an E-ring 113 of a general size similar to the other E-rings 111, 112, and 114 is used as the E-ring 113 fixed to the first support shaft 115, the E-ring 113 does not come into contact with the outer ring of the first ball bearing 141. The paper discharge drive device 100 of this embodiment will be specifically described below.

[0053] Fig. 9 is a schematic configuration diagram showing the first intermediate pulley 105, the first support shaft 115, and the E-ring 113 in this embodiment. Fig. 10 is a perspective view showing the first intermediate pulley 105, the first support shaft 115, and the E-ring 113 in this embodiment. In the following description, the characteristic features will be described, and the description of the same configuration as the conventional one shown in FIGS. 4 and 5 will be omitted as appropriate.

[0054] The first intermediate pulley 105 of this embodiment has an opposing portion 105e that extends rearward, that is, toward one axial side of the first ball bearing 141, and faces the E-ring 113 in the axial direction. By providing the opposing portion 105e on the first intermediate pulley 105 in this manner, the E-ring 113 comes into contact with the opposing portion 105e but does not come into contact with the first ball bearing 141. The first intermediate pulley 105 is made of a resin having slidability, such as POM. Therefore, the sliding of the E-ring 113 against the opposing portion 105e is a sliding motion between metal and resin. Therefore, unlike sliding between metals, the generation of abnormal noise is suppressed.

[0055] Furthermore, there is no longer any restriction that the outer diameter of the E-ring 113 must be equal to or smaller than the inner diameter of the outer ring of the first ball bearing 141. Therefore, in the paper discharge drive device 100, the E-ring 113 fixed to the first support shaft 115 can be an inexpensive, standard-sized E-ring of the same shape as the other E-rings 111, 112, and 114. This prevents the occurrence of incorrect assembly, which was a problem in the past. It also reduces parts management costs. Furthermore, it improves assembly efficiency.

[0056] As shown in FIG. 9(b), the first intermediate pulley 105 of this embodiment has a guide rib 105j, a first positioning portion 105k, and a second positioning portion 105f. As will be described later, the guide rib 105j guides the first ball bearing 141. The guide rib 105j is provided on the inner circumferential surface of the shaft insertion portion 105g of the first intermediate pulley 105. The first positioning portion 105k positions the first ball bearing 141. The second positioning portion 105f positions the second ball bearing 142. The second positioning portion 105f is a tip surface of the guide rib 105j that is perpendicular to the axial direction of the guide rib 105j.

[0057] The rear end (left end in the figure) of the outer ring of the second ball bearing 142 abuts against the second positioning portion 105f. This positions the second ball bearing 142 in front of the first intermediate pulley. Furthermore, the front end (right end in the figure) of the inner ring of the second ball bearing 142 abuts against the second step surface 115d of the first support shaft 115. The second step surface 115d is a surface perpendicular to the axial direction that is a step between the outer peripheral surface of the shaft and the second small diameter portion 115b. In this way, the second ball bearing 142 is axially sandwiched between the second step surface 115d of the first support shaft 115 and the second positioning portion 105f of the first intermediate pulley 105.

[0058] The rear end (left end in the figure) of the outer ring of the first ball bearing 141 abuts against the first positioning portion 105k of the first intermediate pulley 105. As a result, the first ball bearing 141 is positioned on the rear side of the first intermediate pulley 105. Furthermore, the front end (right end in the figure) of the inner ring of the first ball bearing 141 abuts against the first step surface 115c of the first support shaft 115. The first step surface 115c is a surface that is perpendicular to the axial direction and is the step between the second small diameter portion 115b and the first small diameter portion 115a. In this way, the first ball bearing 141 is axially sandwiched between the first step surface 115c of the first support shaft 115 and the first positioning portion 105k of the first intermediate pulley 105.

[0059] The first relay pulley 105 is made of resin and therefore has a large coefficient of thermal expansion. Therefore, the first relay pulley 105 undergoes large radial fluctuations when its temperature rises. The first ball bearing 141 and the second ball bearing 142 are press-fitted into the first relay pulley 105. However, because the first relay pulley 105 undergoes large radial fluctuations when its temperature rises, the thermal expansion of the first relay pulley 105 may reduce the press-fitting force between the first relay pulley 105 and the ball bearings 141 and 142. When the press-fit force between the first relay pulley 105 and the ball bearings 141 and 142 decreases, the ball bearings 141 and 142 become movable in the axial direction relative to the first support shaft 115 and the first relay pulley 105. In this embodiment, as described above, each ball bearing 141 is assembled by being sandwiched between the first support shaft 115 and the first relay pulley 105 in the axial direction. Therefore, even if the press-fitting force between the first intermediate pulley 105 and the ball bearings 141, 142 decreases, the step surfaces 115c, 115d of the first support shaft 155 restrict the ball bearings 141, 142 from moving toward the fixed end of the first support shaft 115 relative to the first intermediate pulley 105. This prevents the ball bearings 141, 142 from coming out of the press-fit portion of the first intermediate pulley 105. Furthermore, the ball bearings 141, 142 restrict the first intermediate pulley 105 from moving toward the fixed end of the first support shaft 155, allowing the first intermediate pulley 105 to be positioned at a predetermined position.

[0060] 9(b), the inner diameter d of the opposing portion 105e of the first intermediate pulley 105 in this embodiment is shorter than the outer diameter of the first ball bearing 141. Therefore, the first ball bearing 141 cannot be inserted from the rear side (left side in the figure) of the first intermediate pulley 105. Therefore, the first ball bearing 141 must be inserted from the front side (right side in the figure) of the first intermediate pulley 105.

[0061] Figure 11 is an oblique view explaining the assembly of the first ball bearing 141 and the second ball bearing 142 to the first intermediate pulley 105, and Figure 12 is a cross-sectional view explaining the assembly of the first ball bearing 141 and the second ball bearing 142 to the first intermediate pulley 105.

[0062] 11 and 12, a plurality of guide ribs 105j are provided at predetermined intervals in the circumferential direction on the inner peripheral surface of the shaft insertion portion 105g. The diameter of an inscribed circle connecting the tops of the guide ribs 105j is approximately the same as the outer diameter of the first ball bearing 141. The first ball bearing 141 is inserted into the shaft insertion portion 105g from the front side of the first intermediate pulley 105 so that its outer peripheral surface contacts the tops of the guide ribs 105j.

[0063] The first ball bearing 141 inserted into the shaft insertion portion 105g is moved rearward while being guided by the multiple guide ribs 105j until the outer ring abuts against the first positioning portion 105k. As a result, the first ball bearing 141 is press-fitted into the first press-fit portion 105m, which has an inner diameter that is one step shorter than the inner circumferential surface of the shaft insertion portion 105g of the first intermediate pulley 105, and the first ball bearing 141 is assembled to the first intermediate pulley 105. In this way, the first ball bearing 141 is assembled while being guided by the multiple guide ribs 105j. As a result, the first ball bearing 141 can be easily assembled to the first intermediate pulley 105 without causing problems such as the first ball bearing 141 tipping over in the axial direction during assembly.

[0064] After the first ball bearing 141 has been assembled, the second ball bearing 142 is press-fitted into the shaft insertion portion 105g from the front side of the first intermediate pulley 105 and abuts against the second positioning portion 105f at the tip of the guide rib 105j. This completes the assembly of the second ball bearing 142 to the first intermediate pulley 105.

[0065] FIG. 13 is a perspective view illustrating the assembly of the first intermediate pulley 105, to which the ball bearings 141 and 142 are attached, onto the first support shaft 115. As shown in FIG. The first intermediate pulley 105 is moved in the direction of arrow A in the figure, and the tip of the first support shaft 115, which is fixed to the rear side plate 1a by caulking or the like, is inserted into the shaft insertion portion 105g from the front side of the first intermediate pulley 105. As a result, the tip of the first support shaft 115 penetrates the first intermediate pulley 105. Also, the inner ring of the first ball bearing 141 abuts against the first step surface 115c of the first support shaft 115, and the inner ring of the second ball bearing 142 abuts against the second step surface 115d of the first support shaft 115. In this way, the first intermediate pulley 105 is assembled to the first support shaft 115. After the first intermediate pulley 105 is assembled, the E-ring 113 is fitted into the groove portion 115e of the first support shaft 115.

[0066] As described above, when first intermediate pulley 105 is assembled to first support shaft 115, the inner ring of first ball bearing 141 abuts against first step surface 115c of first support shaft 115, and first step surface 115c presses first ball bearing 141 rearward. Therefore, even if the outer ring of first ball bearing 141 is not in contact with first positioning portion 105k and the assembly is not correct, the outer ring of first ball bearing 141 can be brought into contact with first positioning portion 105k by being pressed by first step surface 115c. This allows first ball bearing 141 to be assembled to first intermediate pulley 105 correctly.

[0067] Similarly, even if the outer ring of second ball bearing 142 is not in contact with second positioning portion 105f and is not assembled correctly, the outer ring of second ball bearing 142 can be brought into contact with second positioning portion 105f by being pressed in by second step surface 115d. This allows second ball bearing 142 to be assembled correctly to first intermediate pulley 105.

[0068] Furthermore, the first relay pulley 105 of this embodiment has an opposing portion 105e on the rear side, and the rear opening is clearly smaller than the front opening. This makes it easy to visually distinguish between the front and rear sides of the first relay pulley 105, and prevents the first relay pulley 105 from being installed backwards. If the first relay pulley 105 were installed backwards on the first support shaft 115, the inner ring of the first ball bearing 141 would abut against the first step surface 115c of the first support shaft 115. This prevents the first relay pulley 105 from being inserted onto the first support shaft 115 until the tip of the first support shaft 115 penetrates the first relay pulley 105. This prevents the first relay pulley 105 from being installed backwards.

[0069] [Variation 1] FIG. 14 is a schematic configuration diagram of the first modified example, and FIG. 15 is a diagram for explaining the assembly of the first intermediate pulley 105 in the first modified example. In this first modification, a shoulder screw 113A is used as a retaining member for the first relay pulley 105. In this first modification, a threaded hole 115f having a thread groove formed on the inner peripheral surface is provided at the tip of the first support shaft 115. As shown in FIG. 15 , similar to the embodiment, the first relay pulley 105, into which the first ball bearing 141 and the second ball bearing 142 are press-fitted, is moved in the direction of arrow A in the figure to assemble the first relay pulley 105 to the first support shaft 115. Next, the shoulder screw 113A is fastened to the threaded hole 115f of the first support shaft 115. As a result, the head of the shoulder screw 113A faces the opposing portion 105e of the first relay pulley 105, as shown in FIG. 14 . As a result, the shoulder screw 113A can prevent the first relay pulley 105 from coming off the first support shaft 115.

[0070] Because shoulder screw 113A is made of metal, there is a risk of abnormal noise being generated when the head of shoulder screw 113A slides on the outer ring of first ball bearing 141. However, even in this modification 1, first relay pulley 105 is provided with opposing portion 105e, so the head of shoulder screw 113A slides on opposing portion 105e made of a resin material with slidability. This makes it possible to suppress the generation of abnormal noise.

[0071] [Variation 2] FIG. 16 is a schematic diagram of the second modification. This modified example 2 is an example in which the present invention is applied to a two-stage gear 205. The mating member, double gear 205, is made of a slidable resin such as POM and has a large-diameter gear portion 205a and a small-diameter gear 205b. Other than that, the configuration is the same as the above-described embodiment. Specifically, the configuration includes a mechanism for preventing reverse installation of double gear 205 and a mechanism for preventing contact between first ball bearing 141 and E-ring 113.

[0072] The configuration that prevents reverse installation of dual gear 205 is as follows: First ball bearing 141 is press-fitted into one axial side (left side in the figure) of shaft insertion portion 205g, which has a through-hole shape, of dual gear 205, and second ball bearing 142, which is larger in size than first ball bearing 141, is press-fitted into the other axial side (right side in the figure). Support shaft 215 that supports dual gear 205 via ball bearings 141 and 142 has, from the tip side, a first small diameter portion 215a and a second small diameter portion 215b, which has a diameter larger than that of first small diameter portion 215a.

[0073] A configuration in which first ball bearing 141 and E-ring 113 do not come into contact is a configuration in which double gear 205 extends beyond first ball bearing 141 to one side in the axial direction and has opposing portion 205e that axially faces E-ring 113. With this configuration, even in Modification 2, it is possible to prevent abnormal noise from occurring when double gear 205 is driven to rotate.

[0074] [Variation 3] FIG. 17 is a schematic diagram of the third modification. This modified example 3 is an example in which the present invention is applied to a configuration in which the shaft member rotates and the mating member does not rotate. In this third modification, a bearing case 210 made of a resin material is attached to the side plate 1b of the device as a mating member. A ball bearing 120 is disposed between this bearing case 210 and the roller shaft 130b of the drive roller, rotatably supporting the roller shaft 130b. An E-ring 211 is fixed to one end of this roller shaft 130b as a retaining member that prevents the roller shaft 130b from coming off the side plate 1b. The bearing case 210 extends out to one side in the axial direction beyond the ball bearing 120 and has an opposing portion 210e that faces the E-ring 113 in the axial direction.

[0075] In this modification 3, the E-ring 211 rotates together with the roller shaft 130b, but the outer ring of the ball bearing 120 remains stationary because the static frictional force between the E-ring 211 and the bearing case 210 is greater than the frictional force between the balls. Therefore, when the E-ring 211 comes into contact with the outer ring of the ball bearing 120, the E-ring 211 slides on the outer ring. As a result, there is a risk of abnormal noise due to the sliding of metal on metal. However, even in this modification 3, by providing the opposing portion 210e on the bearing case 210 made of resin, the E-ring 211 slides on the opposing portion 210e made of resin. This results in sliding between resin and metal, which can suppress the generation of abnormal noise.

[0076] [Variation 4] FIG. 18 is a schematic diagram of the fourth modification. In this fourth modification, the mounting structure of the ball bearing 120 and the bearing case 210 to the side plate 1b in the third modification of FIG. 17 is changed. In Modification 3, as shown in Fig. 17, a bearing case 210 made of a resin material is attached to the side plate 1b of the device, and a ball bearing 120 is disposed between this bearing case 210 and the roller shaft 130b of the drive roller, with the bearing case 210 rotatably supporting the roller shaft 130b. However, with a configuration in which the outer ring of the ball bearing 120 made of a metal material is directly supported by the bearing case 210 made of a resin material, it is difficult to achieve positional accuracy for the roller shaft 130b. For this reason, the configuration of Modification 3 is difficult to adopt in places where rotational accuracy is required for the roller portion 130a.

[0077] Therefore, in this modification 4, as shown in FIG. 18, the outer ring of the ball bearing 120 is directly supported by the metal side plate 1b, and a bearing case 210 made of a resin material is fixed to the side plate 1b with fastening members 212 such as screws. This configuration improves the positional accuracy of the ball bearing 120. This improves the positional accuracy of the roller shaft 130b, and increases the rotational accuracy of the roller portion 130a. Therefore, in places where rotational accuracy of the roller portion 130a is required, adopting the configuration of modification 4 can satisfy the required rotational accuracy of the roller portion 130a and suppress the generation of abnormal noise.

[0078] In addition, in the modified examples 3 and 4, a resin bearing case 210 is provided, and a facing portion 210e that faces the E-ring 211 is provided on this bearing case 210. However, if the side plate 1b is made of resin, a configuration may be adopted in which the ball bearing 120 is press-fitted into the side plate 1b, and a facing portion that faces the E-ring 211 is provided on this side plate 1b, without the bearing case 210.

[0079] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In a rotating device such as a paper discharge drive device 100 that includes an axial member such as a first support shaft 115, an opposing member such as a first relay pulley 105 having an axial insertion portion 105g into which the axial member is inserted, a bearing such as ball bearings 141, 142 that is provided in the axial insertion portion interposed between the opposing member and the axial member to enable relative rotation, and an anti-slip member such as an E-ring 113 fixed to one axial end of the axial member, the opposing member is located to one side of the bearing and has an opposing portion 105e that faces the anti-slip member in the axial direction. As described above, Patent Document 1 discloses a configuration in which an E-ring serving as a retaining member contacts one axial end of a ball bearing serving as a bearing. A ball bearing includes an inner ring, an outer ring, and balls serving as rolling elements disposed between the inner and outer rings, with the outer and inner rings generally being made of metal. The E-ring is also generally made of metal. Therefore, in the configuration in which the E-ring described in Patent Document 1 contacts one axial end of the bearing, metal-to-metal contact occurs. Because the E-ring rotates together with the paddle shaft relative to the bearing case, if the E-ring contacts the outer ring of the ball bearing, metal-to-metal sliding may occur, potentially generating abnormal noise. In contrast, in the first embodiment, the opposing portion of the mating member that faces the retaining member in the axial direction is located on one side of the bearing in the axial direction, so the retaining member comes into contact with the opposing portion but not with the bearing, thereby preventing the generation of abnormal noise due to the retaining member sliding against the bearing.

[0080] (Aspect 2) In the first aspect, a shaft member such as the first support shaft 115 is supported by a plurality of bearings such as ball bearings 141, 142 having different outer diameters, and the bearing arranged on one side in the axial direction has the smallest outer diameter of the plurality of bearings. As a result, as described in the embodiment, the bearing arranged on one side in the axial direction has the smallest outer diameter of the multiple bearings, and therefore the inner diameter of the outer ring of this bearing is shorter than the outer diameter of the retaining member such as an E-ring. In this configuration, by providing the opposing portion 105e on the mating member, it is possible to prevent the retaining member from sliding against the outer ring of the bearing, without using a small-diameter retaining member such as an E-ring.

[0081] (Aspect 3) In aspect 2, the inner diameter of the opposing portion 105e is smaller than the outer diameter of a bearing such as the first ball bearing 141 arranged on one side in the axial direction, and the inner surface of the shaft insertion portion 105g has a guide rib 105j that guides the bearing arranged on one side in the axial direction. According to this, as described in the embodiment, the inner diameter of the facing portion 105e is smaller than the outer diameter of a bearing, such as first ball bearing 141, arranged on one axial side, so that the bearing arranged on one axial side is inserted from the other axial side of the shaft insertion portion and positioned on one side. In aspect 3, guide rib 105j is provided on the inner peripheral surface of shaft insertion portion 105g, so that the bearing arranged on one axial side and inserted from the other axial side of the shaft insertion portion can be easily moved to one axial side. This improves the ease of assembling the bearing.

[0082] (Aspect 4) In any of aspects 1 to 3, the one end of the shaft member such as the first support shaft 115 is a small diameter portion such as the first small diameter portion 115a that is smaller in diameter than other portions, and two bearings such as ball bearings 141, 142 having different inner diameters are press-fitted into one axial side and the other axial side of the shaft insertion portion 105g, and the bearings are arranged in the small diameter portion of the shaft member and in a portion with a larger diameter than the small diameter portion. According to this, as explained in the embodiment, reverse mounting of a mating member such as the first intermediate pulley 105 to a shaft member such as the first support shaft 115 can be prevented.

[0083] (Aspect 5) In any of aspects 1 to 4, one end of a bearing such as a ball bearing abuts against a surface that faces the axial direction of an axial member such as the first support shaft 115 (in this embodiment, the first step surface 115c and the second step surface 115d), and the other end of the bearing abuts against a surface that faces the axial direction of a mating member such as the first relay pulley 105 (in this embodiment, the first positioning portion 105k and the second positioning portion 105f). As a result, as described in the embodiment, it is possible to prevent the bearing from moving axially relative to the mating member such as the first intermediate pulley 105, and it is possible to prevent the bearing from coming off the mating member.

[0084] (Aspect 6) In any of the first to fifth aspects, the mating member such as the first relay pulley 105 is not in contact with the shaft member such as the first support shaft 115. This makes it possible to suppress a decrease in the contact pressure between the bearing and the mating member.

[0085] (Aspect 7) In any of the first to sixth aspects, the mating member is a drive transmission member such as the first relay pulley 105, and the shaft member is a support shaft such as the first support shaft 115 that supports the drive transmission member. This makes it possible to suppress the generation of abnormal noise during drive transmission, as described in the embodiment.

[0086] (Aspect 8) In any of the first to seventh embodiments, the mating member such as the first relay pulley 105 is made of a resin material, and the bearing is a ball bearing. This prevents the retaining member such as E-ring 113 from sliding on the outer ring of the ball bearing which rotates relative to the retaining member. Also, the resin material acts as a sliding partner for the retaining member, suppressing the generation of abnormal noise.

[0087] (Aspect 9) In an image forming apparatus that includes a rotation device and forms an image on a sheet material, the rotation device of any one of aspects 1 to 8 is used as the rotation device. This makes it possible to suppress the generation of abnormal noise. [Explanation of symbols]

[0088] 1: Image forming unit 1a: Back side plate 1b: Front plate 30: Paper discharge roller pair 31: Pre-discharge roller pair 32: Switchback front roller pair 100: Paper discharge drive unit 101: Paper ejection motor 101a: Motor gear 101b: Stud 102: Reduction gear 103: Drive pulley 104: Tight Narrow 104a: Tightener support shaft 105: First relay pulley 105a: Input pulley section 105b: Output pulley section 105c: First stopper protrusion 105d: Second stopper protrusion 105e: Opposite part 105f: Second positioning part 105g: shaft insertion part 105j: Guide rib 105k: First positioning part 115m: First press-fitting part 106: Paper output pulley 107: Second relay pulley 108: First timing belt 109: Relay gear 110: Paper output gear 111: E-ring 112: E-ring 113: E-Ring 113A: Shoulder screw 114: E-Ring 115: First support shaft 115a: First small diameter section 115b: Second small diameter section 115c: First step surface 115d: Second step surface 115e:Groove 115f: screw hole 116: Second timing belt 117:Second support shaft 141: First ball bearing 141a: Inner circle 141b: outer ring 141c: Ball 142: Second ball bearing 205: Two-stage gear 205a: Large diameter gear section 205b: Small diameter gear 205e: Opposite part 205g: shaft insertion part 210: Bearing case 210e: Opposing part 211: E-ring 215: Support shaft 215a: First small diameter section 215b: Second small diameter section [Prior art documents] [Patent documents]

[0089] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-125374

Claims

1. A shaft member; a mating member having a shaft insertion portion into which the shaft member is inserted; two bearings having inner rings, outer rings, and rolling elements disposed between the inner rings and the outer rings, the bearings being interposed between the mating member and the shaft member and allowing relative rotation therebetween and having different inner ring diameters and provided approximately coaxially within the shaft insertion portion; a retaining member attached to one end of the shaft member in the axial direction, the bearing having an inner ring with a smaller inner diameter of the two bearings is disposed on the one side of the shaft member, the mating member rotates integrally with the outer rings of the two bearings, and has an opposing portion that is disposed between the retaining member and the bearing having the smaller inner diameter of the inner ring in the axial direction, the retaining member is capable of contacting the opposing portion but is incapable of contacting the bearing having an inner ring with a small inner diameter, A rotating device characterized in that the two bearings are configured so as to be mountable to the mating member only from the side where the opposing portion is not provided.

2. An image forming apparatus including a rotation device for forming an image on a sheet material, 2. An image forming apparatus, comprising the rotating device according to claim 1 as the rotating device.

Images