Shaft support device, transfer device, and image forming apparatus

Abstract

To provide a shaft support device that can improve the accuracy of the position of a shaft to be supported.SOLUTION: A shaft support device comprises: a moving member that is fitted to a shaft and movable relative to the shaft; support members that support the ends of the shaft; an opening that is provided at an end of the moving member facing one of the support members and has an inner diameter larger than the diameter of the shaft; and an inclined part that is provided on at least one of an inner surface of the opening and an outer surface of the support member contactable with the inner surface. The inclined part is formed to strengthen the contact between the shaft and the support member as the moving member is moved toward the support member supporting the shaft.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a shaft support device, a transfer device, and an image forming apparatus. [Background technology]

[0002] Conventionally, there is known a shaft support device that can selectively take a detachable state in which the end of a shaft is detachable, and a non-detachable state in which the end is non-detachable. Patent Document 1 describes a shaft support device that includes a bearing that can support the end of a rotating shaft in an inserted state, and the bearing is configured to be capable of selecting between an attached state in which the end of the rotating shaft is rotatably supported, and a detached state in which the end of the rotating shaft is exposed to the outside and can be removed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-271826 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of shaft support device, it is desirable to improve the positional accuracy of the supported shaft. [Means for solving the problem]

[0005] The present invention comprises a movable member engaged with a shaft and movable relative to the shaft, a support member supporting an end of the shaft, an opening provided at an end of the movable member facing the support member and having an inner diameter larger than the diameter of the shaft, and an inclined portion provided on at least one of the inner surface of the opening and the outer surface of the support member capable of contacting the inner surface, wherein the inclined portion is formed so that the contact between the shaft and the support member becomes stronger as the movable member is moved toward the support member supporting the shaft. Effect of the Invention

[0006] According to the present invention, it is possible to provide a shaft support device capable of improving the positional accuracy of the shaft it supports. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an overall configuration of an example of an image forming apparatus according to an embodiment; [Diagram 2] FIG. 2 is a schematic diagram showing an example of an imaging unit. [Diagram 3] FIG. 4 is a schematic configuration diagram of a supporting structure of a secondary transfer unit. [Figure 4] FIG. 1 is an explanatory diagram showing an outline of a shaft support device according to a first embodiment. [Diagram 5] FIG. 2 is an explanatory diagram showing a specific example according to the first embodiment. [Figure 6] FIG. 4 is an explanatory diagram showing another specific example of the first embodiment. [Figure 7] FIG. 4 is an explanatory diagram showing an outline of a shaft support device according to a second embodiment. [Figure 8] FIG. 11 is an explanatory diagram showing a specific example according to the second embodiment. [Figure 9] FIG. 11 is an explanatory diagram showing another specific example of the second embodiment. [Figure 10] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0009] <Configuration of Image Forming Apparatus> First, the configuration of the image forming apparatus will be described.

[0010] 1 is a diagram showing an overall configuration of an example of an image forming apparatus according to an embodiment of the present invention, The image forming apparatus shown is a printer that forms images by an electrophotographic method.

[0011] In the following explanation, the X, Y, and Z directions shown in the figures are as follows: The X direction is the left-right direction of the printer, and the negative side of the X direction (the side opposite to the arrow) is the right side of the printer. The Y direction is the front-to-back direction of the printer, and the negative side of the Y direction (the front side in the figure) is the front side of the printer. The Z direction is the up-down direction of the printer, and the negative side of the Z direction (the side opposite to the arrow) is the bottom side of the printer.

[0012] The printer 1000 includes an image creating section 1, a primary transfer section 2, a sheet supply section 3, a secondary transfer section 4, a fixing section 5, a sheet returning section 6, a sheet discharging section 7, an exposure section 8, a toner container mounting section 9, and the like.

[0013] The imaging section 1 includes a plurality of imaging units 10A, 10B, 10C, 10D, and 10E. Since the imaging units 10A to 10E have the same or equivalent configurations, they will be collectively referred to as imaging unit 10 unless otherwise specified.

[0014] The imaging units 10A to 10E form toner images of different colors. For example, the imaging unit 10B forms a yellow (Y) toner image, the imaging unit 10C forms a magenta (M) toner image, and the imaging unit 10D forms a cyan (C) toner image. The imaging unit 10E forms a black (K) toner image, and the imaging unit 10A forms a toner image of a special color other than Y, M, C, and K.

[0015] The special color is not necessarily limited to a color, and may include a colorless color such as clear toner. The number of imaging units 10 and the order of the colors are not limited to those described above. The number of imaging units 10 may be four or less, or six or more. The order of the colors of the imaging units 10 may be appropriately determined depending on the specifications of the imaging units, the toner characteristics, etc. Here, we will briefly leave FIG. 1 and use FIG. 2 to explain the configuration of the imaging unit 10.

[0016] FIG. 2 is a schematic diagram showing an example of an imaging unit.

[0017] The imaging unit 10 includes a photoconductor module 11, a charging module 12, a developing module 13 and a cleaning module .

[0018] The photoconductor module 11 includes, for example, a cylindrical photoconductor 110. The photoconductor 110 is driven to rotate in a counterclockwise direction (the direction of the arrow) in the drawing.

[0019] The charging module 12 includes, for example, a charging roller 120. The charging roller 120 applies an electric charge to the surface of the photoconductor 110, thereby charging the surface of the photoconductor 110 to a predetermined potential.

[0020] The developing module 13 includes a developing roller 130 that carries a two-component developer containing, for example, toner and a magnetic carrier. The developing roller 130 applies toner to an electrostatic latent image formed by exposing the surface of the photoconductor 110, which is charged to a predetermined potential, by an exposure unit 8 described below, to form a toner image on the surface of the photoconductor 110.

[0021] The cleaning module 14 includes cleaning members such as a cleaning roller 140 and a cleaning blade 141. The cleaning roller 140 and the cleaning blade 141 clean the surface of the photoconductor 110 that has passed through the primary transfer unit 2, which will be described later.

[0022] Returning to FIG. 1, the overall configuration of the printer 1000 will be further described.

[0023] The primary transfer unit 2 is disposed, for example, below the imaging unit 1. The primary transfer unit 2 includes a plurality of primary transfer rollers 20A, 20B, 20C, 20D, and 20E, an intermediate transfer belt 21, a secondary transfer opposing roller 22, and a belt cleaning mechanism 23. The primary transfer rollers 20A to 20E each have the same or similar configuration, and therefore will be collectively referred to as the primary transfer roller 20 unless otherwise distinguished.

[0024] The primary transfer roller 20 is provided at a position facing the photoconductor 110 provided in the imaging unit 10. The primary transfer roller 20 is provided so as to be able to come into contact with the photoconductor 110 via the intermediate transfer belt 21, and by pressing the primary transfer roller 20 against the photoconductor 110, a nip (hereinafter referred to as a primary transfer nip) is formed between the photoconductor 110 and the intermediate transfer belt 21. A bias for primary transfer is applied to the primary transfer roller 20, and an electric field is formed in the primary transfer nip.

[0025] The intermediate transfer belt 21 is an endless belt made of a single layer or multiple layers of materials such as vinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polyimide, polycarbonate, etc. The intermediate transfer belt 21 is stretched around multiple support rollers and moves in a clockwise direction in the drawing.

[0026] The secondary transfer opposing roller 22 forms a nip (hereinafter referred to as a secondary transfer nip) together with a secondary transfer roller 40 provided in a secondary transfer unit 4 described later.

[0027] The belt cleaning mechanism 23 cleans the surface of the intermediate transfer belt 21 that has passed through a secondary transfer roller 40 (secondary transfer nip) described below.

[0028] The sheet supply unit 3 is disposed, for example, at the bottom of the printer 1000. The sheet supply unit 3 includes a tray 30 for stacking sheets S, a delivery mechanism 31 for delivering the sheets S one by one from the tray 30, and a pair of registration rollers 32 and 33 for transporting the sheets S delivered from the delivery mechanism 31 to the secondary transfer unit 4 at a predetermined timing.

[0029] The secondary transfer unit 4 is disposed, for example, below the primary transfer unit 2. The secondary transfer unit 4 includes a secondary transfer roller 40. The secondary transfer roller 40 is provided at a position facing the secondary transfer opposing roller 22 provided in the primary transfer unit 2, and is provided so as to be able to abut against the secondary transfer opposing roller 22 via the intermediate transfer belt 21. The secondary transfer roller 40 is pressed against the secondary transfer opposing roller 22 to form a secondary transfer nip between the secondary transfer roller 40 and the intermediate transfer belt 21. A bias for secondary transfer is applied to the secondary transfer roller 40, and an electric field is formed in the secondary transfer nip.

[0030] The secondary transfer nip is not limited to the configuration formed by the secondary transfer roller 40 and the intermediate transfer belt 21. For example, the secondary transfer unit 4 may be configured to include a secondary transfer belt that is stretched over a plurality of tension rollers including the secondary transfer roller 40, and the secondary transfer roller 40 may be abutted against the intermediate transfer belt 21 (secondary transfer opposing roller 22) via the secondary transfer belt. In this case, a secondary transfer nip is formed between the intermediate transfer belt 21 and the secondary transfer belt. Here, the secondary transfer unit 4 is an example of a "transfer device."

[0031] The fixing unit 5 is disposed, for example, downstream in the sheet conveying direction (positive side in the X direction) with respect to the secondary transfer unit 4. The fixing unit 5 includes a heating roller 50 and a pressure roller 51. The heating roller 50 and the pressure roller 51 can come into contact with each other, and form a nip (hereinafter, referred to as a fixing nip) by coming into contact with each other. The sheet S onto which the toner image has been transferred by the secondary transfer unit 4 is heated and pressurized in the fixing nip, and the toner image is fixed to the sheet S.

[0032] The sheet discharge section 7 is disposed, for example, downstream in the sheet conveying direction with respect to the fixing section 5. The sheet discharge section 7 includes switching mechanisms 70a, 70b, 70c and the like that switch the discharge destination of the sheet S, and conveys the sheet S to the outside of the apparatus or toward the sheet return section 6 described later by the switching mechanisms 70a, 70b, 70c.

[0033] The sheet return unit 6 is disposed, for example, below the sheet discharge unit 7, the fixing unit 5, and the secondary transfer unit 4. The sheet return unit 6 includes a return path 60 provided with a plurality of transport rollers. The end point of the return path 60 merges with the sheet supply unit 3, and the sheet S sent from the sheet discharge unit 7 is transported again toward the secondary transfer unit 4.

[0034] The exposure unit 8 is disposed, for example, above the imaging unit 1. The exposure unit 8 scans the photoconductor 110, which has been charged to a predetermined potential by the charging module 12 described above, with a laser beam L (see FIG. 2), to form an electrostatic latent image on the surface of the photoconductor 110.

[0035] The toner container mounting section 9 is disposed, for example, near the upper side of the exposure section 8. The toner container mounting section 9 detachably holds the toner containers 90A-90E containing the toner used in the imaging units 10A-10E. The toner container mounting section 9 and the imaging section 1 are connected by a toner transfer mechanism, and the toner contained in the toner containers 90A-90E is transferred to the imaging units 10A-10E by the toner transfer mechanism. When it is time to replace the toner containers 90A-90E, they are removed from the toner container mounting section 9 and replaced with new toner containers.

[0036] In the above configuration, when the printer 1000 receives image data from an external computer or the like, it transitions to a print job and starts driving the intermediate transfer belt 21, etc. Then, in the image forming unit 1, the charging roller 120 uniformly charges the surface of the photoconductor 110, which is driven to rotate, to a predetermined charging potential.

[0037] An electrostatic latent image for each color is formed on the charged surface of the photoreceptor 110 by optical scanning using a laser beam emitted by the exposure unit 8 based on image data. The electrostatic latent image is developed into a toner image by the development module 13, and then primarily transferred in order onto the surface of the intermediate transfer belt 21 to become a toner image in which the colors are superimposed. After the toner image is transferred to the intermediate transfer belt 21, the photoreceptor 110 is cleaned by the cleaning module 14, and the toner and the like remaining on the surface of the photoreceptor 110 are removed from the surface of the photoreceptor 110.

[0038] The sheet S sent out from the delivery mechanism 31 of the sheet supply unit 3 is transported until it hits the registration roller pair 32, 33, and the transport is temporarily stopped when the sheet S hits the registration roller pair 32, 33. The registration roller pair 32, 33 then resumes transport in time with the toner image on the intermediate transfer belt 21 reaching the secondary transfer nip. The toner image is secondarily transferred onto the sheet S whose transport has been resumed from the registration roller pair 32, 33 in synchronization with the toner image on the intermediate transfer belt 21 at the secondary transfer nip.

[0039] After the secondary transfer, the sheet S moves to the fixing section 5, which applies heat and pressure to the toner image on the sheet S to fix the toner image to the sheet S. The sheet S then moves to the sheet discharge section 7, and is sent to the outside of the machine or to the sheet return section 6 according to the guidance of switching mechanisms 70a, 70b, and 70c. The sheet return section 6 is mainly used when the sheet S is turned upside down (front and back) and re-sent to the secondary transfer nip, and the sheet S is discharged from the sheet discharge section 7 after the toner image is secondarily transferred to the back side of the sheet S in the secondary transfer nip.

[0040] After passing through the secondary transfer nip, the intermediate transfer belt 21 is cleaned by a belt cleaning mechanism 23 , and toner and the like remaining on the surface of the intermediate transfer belt 21 are removed from the surface of the intermediate transfer belt 21 .

[0041] <Configuration of the secondary transfer unit> FIG. 3 is a schematic diagram of the support structure of the secondary transfer unit, where FIG. 3(b) is a diagram of the secondary transfer unit as viewed from the negative side in the X direction of FIG. 1, FIG. 3(a) is a diagram of FIG. 3(b) as viewed from the negative side in the Y direction, and FIG. 3(c) is a diagram of FIG. 3(b) as viewed from the positive side in the Y direction.

[0042] The secondary transfer unit 4 has five tension rollers that support the inner peripheral surface of the secondary transfer belt 41. Specifically, the five tension rollers are a secondary transfer roller 40, a separation roller 45, a driven roller 46, a drive roller 47, and a stop roller 48. It also has a tension roller 49 that applies pressure to the outer peripheral surface of the secondary transfer belt 41.

[0043] The secondary transfer unit 4 is supported by a support housing 100 that can be pulled out toward the front side (negative side in the Y direction) relative to the main body of the printer 1000. The secondary transfer unit 4 has a pair of roller support plates 42 that support a plurality of tension rollers that tension the secondary transfer belt 41.

[0044] The secondary transfer roller 40, which forms a secondary transfer nip together with the intermediate transfer belt 21, is freely rotatable around a secondary transfer roller shaft 43, which is a fixed shaft. The secondary transfer roller shaft 43 is in contact with the rotating arms 101, 102 at contact surfaces SF1, SF2, and is pressed against the intermediate transfer belt 21 by the pressing forces from the rotating arms 101, 102. The contact surfaces SF1, SF2 are arranged to be approximately perpendicular to a vector connecting the centers of the secondary transfer roller 40 and the secondary transfer opposing roller 22, which faces the secondary transfer roller 40 across the intermediate transfer belt 21. The contact surfaces SF1, SF2 function as reference planes for positioning the secondary transfer unit 4.

[0045] The rotating arms 101 and 102 are supported so as to be freely rotatable about a central axis by support members 105 and 106 that are integral with the support housing 100. Springs 103 and 104 between the rotating arms 101 and 102 and the support housing 100 urge the rotating arms 101 and 102 to rotate. The rotating arms 101 and 102 press the secondary transfer unit 4 against the intermediate transfer belt 21 via contact surfaces SF1 and SF2.

[0046] The shaft support portion of the support member 105 of the front rotating arm 101 supports the support member 105 of the rotating arm 101 so as to be coaxial with the shaft member 44, which is the shaft for positioning the secondary transfer unit 4. This support serves as the main reference for positioning in the up, down, left and right directions (positioning within the XZ plane). The shaft member 44 of the secondary transfer unit 4 is a non-rotating shaft whose both ends are supported by the roller support plates 42, and rotatably supports the driven roller 46 between the roller support plates 42.

[0047] A shaft support device according to an embodiment of the present invention, which will be described later, supports a front shaft member 44 of the secondary transfer unit 4. The shape of the fitting portion of the support member 105 in Fig. 3 which supports this front shaft member 44 is merely a schematic representation of the function of positioning in the up, down, left and right directions, and the specific shape will be described later.

[0048] The shaft support portion of the support member 106 of the rear rotating arm 102 is grooved so as not to restrict the posture of the secondary transfer unit 4, and the groove shape is a groove shape formed of two R shapes concentric with the center of the secondary transfer roller 40. The groove shape that does not restrict the posture is not limited to this, and may be a groove shape that opens at the top and extends vertically. Such a groove shape does not completely position the secondary transfer unit 4 up, down, left, and right, but only partially positions the secondary transfer unit 4, for example, left and right or diagonally, and is a secondary reference for positioning. The secondary transfer unit 4 is positioned so as to be in a predetermined posture by the contact surfaces SF1 and SF2 and the support members 105 and 106.

[0049] The secondary transfer unit 4 is attachable to and detachable from the support housing 100 on the positive side in the Z direction with the support housing 100 pulled out on the negative side in the Y direction from an opening formed in a front side plate of the printer 1000. For this attachment and detachment, it is necessary to release the constraint of at least the shaft member 44, which serves as the main reference for the secondary transfer unit 4. In other words, the end of the shaft member 44 needs to be supported by a shaft support device that can selectively take a removable state in which the constraint is released and the shaft member 44 is removable, and an unremovable state in which the shaft member 44 is restricted up, down, left, and right and cannot be removed.

[0050] In the embodiment, the shaft support device is described based on a configuration in which it is applied to a secondary transfer unit, but the application of the shaft support device is not limited to the secondary transfer unit. The shaft support device can be appropriately applied to devices other than the secondary transfer unit that are detachably provided on the printer 1000 body.

[0051] <Configuration of shaft support device> The configuration of the shaft support device will be described in detail below.

[0052] [First embodiment] FIG. 4 is an explanatory diagram showing an outline of a first embodiment of a shaft support device.

[0053] As described above, the shaft support device supports the shaft member 44 on the front side of the secondary transfer unit 4. Fig. 4 shows a perspective view of the vicinity of the shaft support portion of the support member 105 that penetrates the front rotating arm 101 and protrudes toward the secondary transfer belt 41 side. Here, the shaft member 44 is an example of the "shaft," and the support member 105 is an example of the "support member."

[0054] The support member 105 has, for example, a shaft support portion 105a having an arc-shaped cross section that extends like an eave toward the secondary transfer belt 41. The inner surface of the shaft support portion 105a functions as a support surface 105b that supports the end of the shaft member 44 when the secondary transfer unit 4 is attached to the support housing 100. The outer surface of the shaft support portion 105a is a tapered surface 105c. The tapered surface 105c is formed with an inclination such that the cross-sectional shape becomes larger toward the negative side in the Y direction (the direction away from the end of the shaft member 44). Here, the tapered surface 105c is an example of an "inclined portion."

[0055] The shaft member 44 has a cylindrical moving member 441 on its outer periphery. The moving member 441 is fitted to the shaft member 44 and is provided so as to be movable in the circumferential and axial directions relative to the shaft member 44. Here, the moving member 441 is an example of a "moving member". The relationship between the moving member 441 and the support member 105 will be described later, but generally speaking, the moving member 441 is formed so that an end portion on the side facing the support member 105 (negative side in the Y direction) fits into the tapered surface 105c of the support member 105. After the shaft member 44 is placed on the support surface 105b, the moving member 441 is moved to the negative side in the Y direction, whereby the shaft member 44 is fixed to the support member 105. Hereinafter, the configuration of the moving member 441 will be described with reference to FIG. 5 and FIG. 6.

[0056] Figure 5 is an explanatory diagram showing a specific example of the first embodiment, where Figure 5(a) shows a state in which the end of the shaft member is released from restraint, and Figure 5(b) shows a state in which the end of the shaft member is restrained.

[0057] The cylindrical moving member 441 is fitted to the shaft member 44 and is provided so as to be movable in the circumferential and axial directions relative to the shaft member 44. When the secondary transfer unit 4 is attached to the support housing 100, an end of the shaft member 44 is supported by a support surface 105b of a shaft support portion 105a provided on the support member 105.

[0058] An opening 441a having an inner diameter (diameter d2) larger than the diameter d1 of the shaft member 44 is provided at the end of the moving member 441 on the side facing the support member 105 (negative side in the Y direction). In this example, the inner surface (inner circumferential surface) of the opening 441a is parallel to the shaft member 44, and the outer surface of the support member 105 (shaft support portion 105a) forms a tapered surface 105c. Here, the opening 441a is an example of an "opening".

[0059] 5(b), since the tapered surface 105c is formed so that the cross-sectional shape becomes larger toward the negative side in the Y direction, a force is generated that moves the moving member 441 toward the negative side in the Z direction. Then, as the moving member 441 is moved, the contact between the shaft member 44 and the support member 105 (support surface 105b) gradually becomes stronger, and the shaft member 44 is fixed to the support surface 105b.

[0060] As described above, this embodiment comprises a movable member 441 engaged with the shaft member 44 and movable relative to the shaft member 44, a support member 105 supporting the end of the shaft member 44, an opening 441a provided at the end of the movable member 441 facing the support member 105 and having an inner diameter (diameter d2) larger than the diameter d1 of the shaft member 44, and a tapered surface 105c provided on the outer surface of the support member 105 capable of contacting the inner surface of the opening 441a, and the tapered surface 105c is formed so that the contact between the shaft member 44 and the support member 105 becomes stronger as the movable member 441 is moved toward the support member 105 supporting the shaft member 44.

[0061] As described above, the tapered surface 105c is provided on the outer surface of the support member 105 (shaft support portion 105a), and is formed so that the cross-sectional shape (cross-sectional area) of the outer surface becomes larger as it moves away from the end portion 105d of the support member 105 that faces the movable member 441 (towards the negative side in the Y direction).

[0062] As a result, the positional accuracy of the shaft member 44 can be improved.

[0063] The moving member 441 is made of a material capable of deforming by a predetermined amount, and the moving member 441 is formed such that the inner diameter of the portion other than the opening 441a when removed from the shaft member 44 is a predetermined amount smaller than the diameter d1 of the shaft member 44. This makes it difficult for play (backlash) to occur between the shaft member 44 and the moving member 441 when the moving member 441 is fitted into the shaft member 44, so that the force that moves the moving member 441 to the negative side in the Z direction can be transmitted to the shaft member 44 with greater accuracy.

[0064] Moreover, the surface quality of the shaft member 44 is specified to be Rz (maximum height) 3.5 μm.

[0065] As a result, even when the shaft member 44 is repeatedly attached and detached, wear between the members is less likely to occur, and the shaft member 44 can be stably positioned.

[0066] In this example, the movement of the moving member 441 relative to the shaft member 44 is performed by a screw feed. For example, a screw 44a is provided on the outer periphery of the shaft member 44, and a screw groove 441b is provided on the inner periphery of the portion of the moving member 441 that engages with the shaft member 44, so that the screw 44a and the screw groove 441b mesh with each other.

[0067] The screw 44a and the screw groove 441b may be provided at least in a range that moves the moving member 441 toward the support member 105, but may be provided over the entire axial direction of the shaft member 44 and the moving member 441. Here, the screw 44a and the screw groove 441b are an example of a "threaded portion."

[0068] As described above, this embodiment is provided with a screw portion (screw 44a, screw groove 441b) between the shaft member 44 and the movable member 441 for screwing the movable member 441 at least within a range in which the movable member 441 moves toward the support member 105.

[0069] This makes it possible to rotate the moving member 441 and move the moving member 441 to any position.

[0070] Figure 6 is an explanatory diagram showing another specific example of the first embodiment, where Figure 6(a) shows a state in which the end of the shaft member is released from restraint, and Figure 6(b) shows a state in which the end of the shaft member is restrained.

[0071] 6, a spring is used to move the moving member 441 relative to the shaft member 44. For example, a plate-shaped member 44b is fixed onto the shaft member 44 on the Y-direction positive side relative to the moving member 441, and a spring 44c is provided between this plate-shaped member 44b and the end face of the moving member 441, so that the moving member 441 is always biased toward the support member 105 side by the elastic force of the spring 44c.

[0072] The spring 44c has an amount of extension that allows the opening 441a of the moving member 441 to come into contact with the tapered surface 105c of the support member 105 and to apply a sufficient pressing force. Here, the spring 44c is an example of the "biasing means".

[0073] As described above, in this embodiment, the spring 44c that biases the moving member 441 toward the support member 105 is provided between the shaft member 44 and the moving member 441.

[0074] As a result, the movable member 441 is always biased toward the support member 105. Therefore, even if the contact area between the opening 441a and the tapered surface 105c becomes worn, the wear is absorbed by the bias, and the fixed position of the shaft member 44 can be maintained.

[0075] [Second embodiment] FIG. 7 is an explanatory diagram showing an outline of a shaft support device according to a second embodiment.

[0076] The shaft support device supports the front shaft member 44 of the secondary transfer unit 4 as in the first embodiment, and Fig. 7 shows a perspective view of the vicinity of the shaft support portion of the support member 105' that penetrates the front rotating arm 101 and protrudes toward the secondary transfer belt 41. Here, the shaft member 44 is an example of the "shaft," and the support member 105' is an example of the "support member."

[0077] The support member 105' has, for example, a shaft support portion 105a' having an arc-shaped cross section that extends like an eave toward the secondary transfer belt 41. The inner surface of the shaft support portion 105a' functions as a support surface 105b' that supports the end of the shaft member 44 when the secondary transfer unit 4 is attached to the support housing 100. The outer surface of the shaft support portion 105a' is not a tapered surface as in the first embodiment, but is an outer circumferential surface 105c' that is parallel to the support surface 105b'.

[0078] The shaft member 44 has a cylindrical moving member 441' on its outer periphery. The moving member 441' is fitted to the shaft member 44 and is provided so as to be movable in the circumferential and axial directions relative to the shaft member 44. Here, the moving member 441' is an example of a "moving member". The relationship between the moving member 441' and the support member 105' will be described later, but generally speaking, the moving member 441' is formed so that an end portion on the side facing the support member 105' fits into the outer periphery surface 105c' of the support member 105'. After the shaft member 44 is placed on the support surface 105b', the moving member 441' is moved to the negative side in the Y direction, whereby the shaft member 44 is fixed to the support member 105'. The configuration of the moving member 441' will be described below with reference to FIG. 8 and FIG. 9.

[0079] Figure 8 is an explanatory diagram showing a specific example of the second embodiment, where Figure 8(a) shows a state in which the end of the shaft member is released from constraint, and Figure 8(b) shows a state in which the end of the shaft member is constraint.

[0080] As described above, the cylindrical moving member 441' is fitted to the shaft member 44 and is provided so as to be movable in the circumferential and axial directions relative to the shaft member 44. When the secondary transfer unit 4 is attached to the support housing 100, the end of the shaft member 44 is supported by the support surface 105b' of the shaft support portion 105a' provided on the support member 105'.

[0081] An opening 441a' having an inner diameter (diameter d3) larger than the diameter d1 of the shaft member 44 is provided at the end of the moving member 441' on the side facing the support member 105' (negative side in the Y direction). In the second embodiment, the outer surface (outer peripheral surface 105c') of the support member 105' (shaft support portion 105a') is parallel to the shaft member 44, and the inner surface of the opening 441a' is a tapered surface 441c'. Here, the opening 441a' is an example of an "opening".

[0082] The tapered surface 441c' is formed such that the cross-sectional shape (cross-sectional area) of the opening 441a' becomes smaller from the end 441d' of the opening 441a' toward the positive side in the Y direction. The end of the opening 441a' has an inner diameter (diameter d2) that is larger than the diameter d1 of the shaft member 44 and smaller than the inner diameter (diameter d3) at the end 441d'. Here, the tapered surface 441c' is an example of an "inclined portion". In this case, the outer circumferential surface 105c' of the support member 105' is provided so as to be located between the inner diameter (diameter d2) and the inner diameter (diameter d3) of the opening 441a'.

[0083] In the above configuration, when the moving member 441' is moved toward the support member 105' as shown in Fig. 8(b), a force is generated that moves the moving member 441' toward the negative side in the Z direction because the tapered surface 441c' is formed so that the cross-sectional shape becomes smaller toward the negative side in the Y direction. Then, as the moving member 441' is moved, the contact between the shaft member 44 and the support member 105' (support surface 105b') gradually becomes stronger, and the shaft member 44 is fixed to the support surface 105b'.

[0084] As described above, this embodiment includes a movable member 441' that is engaged with the shaft member 44 and is movable relative to the shaft member 44, a support member 105' that supports the end of the shaft member 44, an opening 441a' that is provided at the end of the movable member 441' facing the support member 105' and has an inner diameter (diameter d3) larger than the diameter d1 of the shaft member 44, and a tapered surface 441c' that is provided on the inner surface of the opening 441a' that is capable of contacting the outer circumferential surface 105c' of the support member 105', and the tapered surface 441c' is formed so that the contact between the shaft member 44 and the support member 105' becomes stronger as the movable member 441' is moved toward the support member 105' that supports the shaft member 44.

[0085] As described above, tapered surface 441c' is provided on the inner surface of opening 441a', and is formed so that the cross-sectional shape (cross-sectional area) of opening 441a' becomes smaller as it moves away from end 441d' of opening 441a' that faces support member 105' (towards the positive Y-direction).

[0086] As a result, the positional accuracy of the shaft member 44 can be improved.

[0087] The moving member 441' is made of a material capable of deforming by a predetermined amount, and the moving member 441' is formed such that the inner diameter of the portion other than the opening 441a' when removed from the shaft member 44 is a predetermined amount smaller than the diameter d1 of the shaft member 44. This makes it difficult for play (backlash) to occur between the shaft member 44 and the moving member 441' when the moving member 441' is fitted into the shaft member 44, so that the force that moves the moving member 441' to the negative side in the Z direction can be transmitted to the shaft member 44 with greater accuracy.

[0088] Moreover, the surface quality of the shaft member 44 is specified to be Rz (maximum height) 3.5 μm.

[0089] As a result, even when the shaft member 44 is repeatedly attached and detached, wear between the members is less likely to occur, and the shaft member 44 can be stably positioned.

[0090] In this example, the movement of the moving member 441' relative to the shaft member 44 is performed by a screw feed. For example, a screw 44a is provided on the outer periphery of the shaft member 44, and a screw groove 441b' is provided on the inner periphery of the portion of the moving member 441' that engages with the shaft member 44, so that the screw 44a and the screw groove 441b' mesh with each other.

[0091] The screw 44a and the screw groove 441b' may be provided at least in a range that moves the moving member 441' toward the support member 105', but may be provided over the entire axial direction of the shaft member 44 and the moving member 441'. Here, the screw 44a and the screw groove 441b' are an example of a "threaded portion."

[0092] As described above, in this embodiment, a screw portion (screw 44a, screw groove 441b') is provided between the shaft member 44 and the movable member 441' for screwing the movable member 441' at least within a range in which the movable member 441' is moved toward the support member 105'.

[0093] This makes it possible to rotate the moving member 441' and move the moving member 441' to any position.

[0094] Figure 9 is an explanatory diagram showing another specific example of the second embodiment, where Figure 9(a) shows a state in which the end of the shaft member is released from restraint, and Figure 9(b) shows a state in which the end of the shaft member is restrained.

[0095] 9, a spring is used to move the moving member 441' relative to the shaft member 44. For example, a plate-shaped member 44b is fixed onto the shaft member 44 on the Y-direction positive side relative to the moving member 441', and a spring 44c is provided between this plate-shaped member 44b and the end face of the moving member 441' so that the elastic force of the spring 44c always biases the moving member 441' toward the support member 105'.

[0096] The spring 44c has an amount of extension that allows the tapered surface 441c' of the moving member 441' to contact the outer circumferential surface 105c' of the support member 105' and to apply a sufficient pressing force. Here, the spring 44c is an example of the "biasing means".

[0097] As described above, in this embodiment, the spring 44c is provided between the shaft member 44 and the moving member 441' to bias the moving member 441' towards the support member 105'.

[0098] As a result, the movable member 441' is always biased toward the support member 105'. Therefore, even if, for example, the contact area between the tapered surface 411c' and the outer circumferential surface 105c' becomes worn, the wear is absorbed by the bias, and the fixed position of the shaft member 44 can be maintained.

[0099] In the above first and second embodiments, the tapered surface, which is an example of an inclined portion, is configured to be provided on the outer surface of the support member (105) or the inner surface of the opening (441a') of the moving member, but the configuration of the inclined portion is not limited to this. For example, inclined portions may be provided on both the support member and the moving member, and the inclined portions may be brought into contact with each other to fix the shaft member. An example of this will be described below.

[0100] <Modification> FIG. 10 is an explanatory diagram showing a modified example.

[0101] The inclined portions provided on the support member and the moving member are not limited to tapered surfaces with a constant inclination as described above, but may be curved surfaces including a curve that is convex outward as shown in the figure.

[0102] In Figure 10(a), the support member has the same configuration as the support member 105 shown in the first embodiment, and the movable member 442 has a curved surface 442c that bulges toward the tapered surface 105c of the support member 105 as an inclined portion formed at its opening.

[0103] In FIG. 10(b), the movable member has the same configuration as the movable member 441′ shown in the second embodiment, and the support member 107 has a curved surface 107c that bulges toward the tapered surface 441c′ of the movable member 441′ as an inclined portion formed on its outer surface.

[0104] In FIG. 10(c), both the support member 107 and the moving member 442 have curved surfaces 107c, 442c that bulge outward as inclined portions.

[0105] In any of the configurations shown in Figures 10(a) to (c), the curvature and inclination angle of the ends 105d, 107d of the support members 105, 107 are selected so that they are slightly raised above the inclined portions (curved surface 442c, tapered surface 441c') of the movable members 442, 441' (without contacting curved surface 442c, tapered surface 441c').

[0106] As described above, in this embodiment, the inclined portion is formed into an outwardly convex curved shape.

[0107] As a result, for example, when the shaft member 44 is fixed to the support surfaces 105b, 107b, the surfaces of the inclined portions (curved surface 442c, tapered surface 441c') are less likely to be scraped by the edges of the ends 105d, 107d of the support member, thereby improving the durability of the member and extending its lifespan.

[0108] What has been described above is one example, and other embodiments, additions, modifications, deletions, and other changes can be made within the scope of what a person skilled in the art can imagine. As long as the effects of the present invention are achieved in any of the following aspects, they are included in the scope of the present invention.

[0109] [Aspect 1] Aspect 1 comprises a movable member (e.g., movable member 441) engaged with a shaft (e.g., shaft member 44) and movable relative to the shaft, a support member (e.g., support member 105) supporting an end of the shaft, an opening (e.g., opening 441a) provided at an end of the movable member facing the support member and having an inner diameter (e.g., diameter d2) larger than the diameter (e.g., diameter d1) of the shaft, and an inclined portion (e.g., tapered surface 105c) provided on at least one of the inner surface of the opening and the outer surface of the support member capable of contacting the inner surface, and the inclined portion is formed so that the contact between the shaft and the support member becomes stronger as the movable member is moved toward the support member supporting the shaft.

[0110] [Aspect 2] Aspect 2 is characterized in that, in aspect 1, the inclined portion (e.g., tapered surface 105c) is provided on the outer surface of the support member (e.g., support member 105), and is formed so that the cross-sectional shape of the outer surface becomes larger as it moves away from the end of the support member that faces the movable member (e.g., movable member 441).

[0111] [Aspect 3] A third aspect is characterized in that, in the first or second aspect, the inclined portion (e.g., tapered surface 441c') is provided on the inner surface of the opening (e.g., opening 441a') and is formed so that the cross-sectional shape of the opening becomes smaller as it moves away from the end of the opening facing the support member (e.g., support member 105').

[0112] [Aspect 4] A fourth aspect is characterized in that in any one of the first to third aspects, the inclined portion is formed into an outwardly convex curved shape (for example, curved surface 107c, curved surface 442c).

[0113] [Aspect 5] Aspect 5 is characterized in that in any of aspects 1 to 4, a screw portion (e.g., screw 44a, screw grooves 441b, 441b') is provided between the shaft (e.g., shaft member 44) and the movable member (e.g., movable members 441, 441') for screwing the movable member at least within a range in which the movable member is moved toward the support member.

[0114] [Aspect 6] Aspect 6 is characterized in that in any of aspects 1 to 4, a biasing means (e.g., spring 44c) is provided between the shaft (e.g., shaft member 44) and the movable member (e.g., movable members 441, 441') for biasing the movable member toward the support member.

[0115] [Aspect 7] A seventh aspect is characterized in that in any one of the first to sixth aspects, the surface texture of the shaft (for example, the shaft member 44) is specified to have Rz (maximum height) of 3.5 μm.

[0116] [Aspect 8] Aspect 8 is a transfer device (e.g., secondary transfer section 4) that is detachable from the image forming apparatus body and includes an axis (e.g., axis member 44) for positioning relative to the image forming apparatus body, and is characterized in that the axis support device of any of aspects 1 to 7 is used to support the positioning axis.

[0117] [Aspect 9] A ninth aspect is an image forming apparatus including a transfer device, characterized in that the transfer device of the eighth aspect is used as the transfer device (for example, the printer 1000).

[0118] [Aspect 10] Aspect 10 is an image forming apparatus (e.g., printer 1000) that is equipped with a device (e.g., secondary transfer unit 4) that is detachable from the image forming apparatus main body, the device having an axis (e.g., axis member 44) for positioning with respect to the image forming apparatus main body, and that uses an axis support device of any of aspects 1 to 7 to support the positioning axis. [Explanation of symbols]

[0119] 4 Secondary transfer section 44 Shaft member 44a Screw 44b Plate-shaped member 44c spring 441, 441´, 442 Moving parts 441a,441a´ opening 441b,441b´ Thread groove 100 Supporting housing 101,102 Rotating arm 105, 105´, 106, 107 Support member 105a,105a´,107a Shaft support part 105b,105b´,107b Support surface 105c,441c´ Tapered surface 105c´ Outer surface 105d,107d,441d´ End 107c,442c curved surface

Claims

1. a moving member engaged with the shaft and movable relative to the shaft; A support member for supporting an end of the shaft; an opening provided at an end of the moving member facing the support member and having an inner diameter larger than a diameter of the shaft; an inclined portion provided on at least one of an inner surface of the opening and an outer surface of the support member capable of contacting the inner surface; A shaft support device characterized in that the inclined portion is formed so that the contact between the shaft and the support member becomes stronger as the movable member is moved toward the support member that supports the shaft.

2. The inclined portion is provided on the outer surface of the support member, 2. The shaft support device according to claim 1, wherein the cross-sectional shape of the outer surface is formed so as to become larger with increasing distance from the end of the support member facing the movable member.

3. The inclined portion is provided on the inner surface of the opening, 2. The shaft support device according to claim 1, wherein the cross-sectional shape of the opening is formed to become smaller as it goes away from the end of the opening facing the support member.

4. 2. The shaft support device according to claim 1, wherein said inclined portion is formed in an outwardly convex curve.

5. 2. The shaft support device according to claim 1, further comprising a screw portion provided between the shaft and the movable member for screwing the movable member at least within a range for moving the movable member toward the support member.

6. 2. The shaft support device according to claim 1, further comprising a biasing means between said shaft and said moving member for biasing said moving member toward said support member.

7. 2. A shaft support device according to claim 1, wherein the surface quality of said shaft is specified to be Rz (maximum height) 3.5 μm.

8. In a transfer device detachable from an image forming apparatus body, A shaft for positioning the image forming apparatus body is provided, 8. A transfer device, comprising: a shaft support device according to claim 1 for supporting the positioning shaft.

9. In an image forming apparatus equipped with a transfer device, 9. An image forming apparatus comprising the transfer device according to claim 8 as a transfer device.

10. In an image forming apparatus having a device detachable from a main body of the image forming apparatus, the device includes a shaft for positioning relative to the image forming apparatus body, 8. An image forming apparatus, comprising: a shaft support device according to claim 1 for supporting said positioning shaft.

Images