JP2024048255A - Shaft support device, transfer device and image forming device - Google Patents

Abstract

A shaft support device capable of improving the positional accuracy of a supported shaft is provided.
[Solution] In a shaft support device that can selectively take an end of a shaft 118 between a detachable state where the end is detachable and an undetachable state where the end is not detachable, the device includes a holding part 300 that detachably holds the end, and a biasing force applying means 200 that applies a biasing force toward the holding part 300 to the end to bring it into the undetachable state and releases the biasing force to bring it into the detachable state. The biasing force applying means 200 is configured using a movable member 200 that can selectively take a position in which it exerts a biasing force by abutting against another member 300, and a position in which it does not exert a biasing force. An abutting portion 204 of the movable member 200 with the other member 300 is formed into a convex shape.
[Selected figure] Figure 5

Description

The present invention relates to a shaft support device, a transfer device, and an image forming device.

2. Description of the Related Art Conventionally, there is known a shaft support device that can selectively take a detachable state in which an end of a shaft is detachable and a non-detachable state in which the end is non-detachable.
Patent Document 1 describes an image forming apparatus equipped with such a shaft support device. The shaft support device includes a bearing capable of supporting an end of a rotating shaft by inserting it therein, and a bearing installation portion into which a portion of the bearing in the axial direction can be inserted. One of the bearings includes a base portion rotatably supported by the bearing installation portion, and a support surface portion that is continuous with the base portion and extends toward the other side of the bearing and has a shape capable of covering a semi-circumferential surface of the rotating shaft. During the course of rotation, the support surface portion can select between an attached state in which the rotating shaft is rotatably supported by facing a surface corresponding to the direction in which the load acts on the rotating shaft, and a detached state in which the support surface portion does not face the surface and the rotating shaft is exposed so as to be removable.

In this type of shaft support device, it is desirable to improve the positional accuracy of the supported shaft.

In order to solve the above-mentioned problems, the present invention provides a shaft support device that can selectively take an end of a shaft between a removable state where the end of the shaft is removable and an unremovable state where the end of the shaft is not removable, the device includes a holding part that holds the end of the shaft in a removable manner, and a biasing force applying means that applies a biasing force toward the holding part to the end of the shaft to bring it into the unremovable state and releases the biasing force to bring it into the removable state, the biasing force applying means is configured using a movable member that can selectively take a position in which it exerts the biasing force by contacting another member and a position in which it does not exert the biasing force, and the portion of the movable member that contacts the other member is formed into a convex shape.

According to the present invention, the shaft support device can improve the positional accuracy of the supported shaft.

1 is a schematic diagram of an image forming apparatus according to an embodiment; FIG. 4 is a schematic diagram of a supporting structure of the secondary transfer device. FIG. 2 is an explanatory diagram of a shaft support device according to the embodiment. 5A to 5C are explanatory diagrams of a procedure for supporting a shaft member. FIG. 4 is an explanatory diagram of the rotation of a shaft opposing portion.

The following describes an embodiment of the present invention with reference to the drawings. FIG. 1 is a schematic diagram of an electrophotographic color printer (hereinafter referred to as "printer") as an image forming apparatus according to an embodiment. This printer 100 has four image forming units 1Y, 1M, 1C, and 1K for forming toner images of yellow (Y), magenta (M), cyan (C), and black (K). It also has a transfer unit 30 as an intermediate transfer device, a secondary transfer device 40, a cassette 60 that stores recording material P as an object to be transported, a fixing device 90, and the like.

The four image forming units 1Y, 1M, 1C, and 1K that make up the image forming section use different color toners of Y, M, C, and K as powder developers. Otherwise, they have the same configuration. The image forming units 1Y, 1M, 1C, and 1K each include drum-shaped photoconductors 2Y, 2M, 2C, and 2K that serve as image carriers, drum cleaning devices 3Y, 3M, 3C, and 3K, static eliminators, charging devices 6Y, 6M, 6C, and 6K, and developing devices 8Y, 8M, 8C, and 8K.

The surfaces of the photoreceptors 2Y, 2M, 2C, and 2K are uniformly charged by the charging devices 6Y, 6M, 6C, and 6K. Next, the surfaces are optically scanned with exposure light such as laser light emitted from the optical writing unit 101 disposed above the image forming units 1Y, 1M, 1C, and 1K to form electrostatic latent images for each color. These electrostatic latent images are developed by the developing devices 8Y, 8M, 8C, and 8K having toner of each color to become toner images T for each color. A toner image is formed on the photoreceptor 2. The toner images T on the photoreceptors 2Y, 2M, 2C, and 2K are primarily transferred and carried on the front surface of the intermediate transfer belt 31, which is an endless belt member.

Below the image forming units 1Y, 1M, 1C, and 1K, there is disposed a transfer unit 30, which is an intermediate transfer device that moves (rotates) an intermediate transfer belt 31 endlessly in a clockwise direction in the drawing while tensioning it. In this embodiment, the surface movement direction of the intermediate transfer belt 31 is defined as the belt movement direction a.

In addition to the intermediate transfer belt 31, the transfer unit 30 includes a drive roller 32, a secondary transfer back roller 33, a cleaning backup roller 34, four primary transfer rollers 35Y, 35M, 35C, and 35K, and a pre-transfer roller 37. The intermediate transfer belt 31 is supported and tensioned by being wrapped around the drive roller 32, the secondary transfer back roller 33, the cleaning backup roller 34, the primary transfer rollers 35Y, 35M, 35C, and 35K, and the pre-transfer roller 37. The intermediate transfer belt 31 is endlessly moved and transported in the clockwise direction by the rotational force of the drive roller 32, which is driven to rotate in the clockwise direction in the figure by a drive means such as a drive motor.

A secondary transfer device 40 is disposed below the outer loop of the intermediate transfer belt 31. The secondary transfer belt 102 is a belt member and a transfer belt. The secondary transfer belt 102 is wound around multiple tension rollers including a secondary transfer roller 41.

A cassette 60 is disposed below the secondary transfer device 40 and serves as a storage section capable of storing a stack of multiple recording materials P. This cassette 60 has a roller 60a in contact with the top recording material P of the stack, and by rotating the roller 60a at a predetermined timing, the recording material P is sent from the cassette 60 to a conveying path 65 toward the secondary transfer nip N2. The recording material P sent to the conveying path 65 is sent to the secondary transfer nip N2 by a pair of registration rollers 61 at a timing synchronized with the toner image on the front surface of the intermediate transfer belt 31 within the secondary transfer nip N2.

The toner image on the front surface of the intermediate transfer belt 31 is transferred in bulk onto the recording material P at the secondary transfer nip N2 by the action of the secondary transfer electric field and nip pressure, and becomes a full-color toner image combined with the white color of the recording material P.

The fixing device 90 is disposed downstream of the secondary transfer nip N2 in the recording material conveying direction b. The fixing device 90 includes a heating roller 91, a fixing roller 93, a support roller 96, and a tension roller 95, which also functions as a tension member, as support rollers for the fixing belt 94. The fixing device 90 also includes a pressure roller 92 that contacts the fixing roller 93 with the fixing belt 94 sandwiched between them. The recording material P to which the toner image has been transferred is fed into the fixing device 90 and is sandwiched in the fixing nip where the fixing roller 93 and the pressure roller 92 are in contact. The fixing device 90 applies pressure to the nip and transfers heat from the heating roller 91, which has a heat source inside, to the recording material P via the fixing belt 94, softening the toner in the full-color toner image and fixing it. After fixing, the recording material P is discharged from the fixing device 90 and discharged outside the machine.

In FIG. 1, the secondary transfer device 40 has five tension rollers that support the secondary transfer belt 102 on the inner peripheral side of the belt. Specifically, the five tension rollers are a secondary transfer roller 41, a separation roller 42, a driven roller 43, a drive roller 44, and a stop roller 45. It also has a tension roller 46 that presses the secondary transfer belt 406 from the outer peripheral side. The secondary transfer device 40 is supported by a pull-out housing 113, which is a support housing that can be pulled out toward the front side of the device (X direction) from the device main body. FIG. 1 is a front view of the schematic configuration of the printer, and the X, Y, and Z directions shown in the figure are as follows. The X direction is the front direction from the front of the printer, the Y direction is the right direction from the left to the right of the printer, and the Z direction is the vertical upward direction.

Figure 2 is a schematic diagram of the support structure of the secondary transfer device 40. The X, Y, and Z directions shown in Figure 2 are the same as those in Figure 1. The diagram in the center on the left and right is a view of the secondary transfer device 40 from the left side of the printer, the diagram on the left is a view from the rear side of the printer, and the diagram on the right is a view from the front side of the printer. The secondary transfer device 40 has a pair of roller support plates 103 as roller support members that support multiple tension rollers that tension the secondary transfer belt 102.

The secondary transfer roller 41, which forms the secondary transfer nip N2 (see FIG. 1) with the intermediate transfer belt 31, is free to rotate around the secondary transfer roller shaft 107, which is a fixed shaft. The secondary transfer roller shaft 107 is in contact with the rotating arms 108, 109 at contact surfaces 110, 111, and is pressed against the intermediate transfer belt 31 by the pressing forces from the rotating arms 108, 109. The contact surfaces 110, 111 are arranged to be approximately perpendicular to the vector connecting the centers of the secondary transfer roller 41 and the secondary transfer back roller 33, which faces the secondary transfer roller 41 across the intermediate transfer belt 31. The contact surfaces 110, 111 function as reference planes for positioning the secondary transfer device 40.

The rotating arms 108, 109 are supported by the rotating center shaft members 116, 117 integral with the drawer housing 113 so as to be freely rotatable around the center shaft. Springs 114, 115 between the rotating arms 108, 109 and the drawer housing 113 urge the rotating arms 108, 109 to rotate. The rotating arms 108, 109 press the secondary transfer device 40 against the intermediate transfer belt 31 via the contact surfaces 110, 111. The shaft support portion of the rotating center shaft member 116 of the front rotating arm 108 fits and supports the rotating center shaft member 116 of the rotating arm 108 so as to be concentric with the shaft member 118 of the secondary transfer device 40. This fitting support serves as the main reference for positioning up, down, left, and right (positioning within the YZ plane). The shaft member 118 of the secondary transfer device 40 is a non-rotating shaft whose both ends are supported by the roller support plates 103, and rotatably supports the driven roller 43 shown in FIG. 1 between the roller support plates 103.

The shaft support device according to the embodiment of the present invention, which will be described later, supports a front shaft member 118 of the secondary transfer device 40. The shape of the fitting portion of the rotation center shaft member 116 in FIG. 2, which supports this front shaft member 118, is merely a schematic representation of its function of positioning in the up, down, left, and right directions, and the specific shape will be described later.

The shaft support portion of the rotation center shaft member 117 of the rear rotating arm 109 is grooved so as not to restrict the posture of the secondary transfer device 40, and the groove shape is a groove shape formed by two R shapes concentric with the center of the secondary transfer roller 41. 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 device up, down, left, and right, but only partially positions the device left and right or diagonally, and is a secondary reference for positioning. The secondary transfer device 40 is positioned so that it is in a specified posture by the contact surfaces 110, 111 and the rotation center shaft members 116, 117.

The secondary transfer device 40 can be attached to and detached from the drawer housing 113 in the Z direction (vertical direction) when the drawer housing 113 is pulled out in the X direction from an opening formed in the front side panel of the printer 100. To attach and detach the secondary transfer device 40, it is necessary to release the restraint of at least the shaft member 118, which serves as the main reference for the secondary transfer device 40. In other words, the end of the shaft member 118 needs to be supported by a shaft support device that can selectively take a removable state in which the restraint is released and the shaft member 118 can be attached and detached, and an unremovable state in which the shaft member 118 is restrained vertically and horizontally and cannot be attached and detached.

Figure 3 is an explanatory diagram of the shaft support device according to the embodiment. As described above, it supports the front shaft member 118 of the secondary transfer device 40. Figure 3 (a) is a perspective view of the vicinity of the shaft support portion of the rotation center shaft member 116 that penetrates the front rotating arm 108 and protrudes to the belt side. This shaft support device is equipped with a semicircular hollow cylindrical holding portion 300 that is cut in a 180° range and has an opening facing upward as a holding portion that detachably holds the end of the shaft member 118. In the illustrated example, the holding portion 300 is extended to the part of the rotation center shaft member 116 that penetrates the front rotating arm 108 and reaches the belt side. The inner surface 301 of the holding portion 300 becomes the holding surface, and the outer peripheral surface 302 of the holding portion 300 has a recess 303 that extends in the axial direction at a location approximately in the center in the circumferential direction.

The shaft support device also has a fixed member 200 as a force applying means for applying a force to the end of the shaft member 118 toward the inner surface 301 of the holding part 300 to make the shaft unremovable, and releasing the force to make the shaft removable. The fixed member 200 is a movable member that is rotatably attached to the shaft member 118. As shown in FIG. 3(b), which is a perspective view of the shaft member 118 from the shaft end side, the fixed member 200 has a cylindrical base end 201 that is rotatably attached to the shaft member 118, and a shaft opposing part 202 that is a semicircular hollow cylinder extending from the base end 201 and exists within an angular range of 180°. The orientation of the opening of the shaft opposing part 202 changes when rotated.

The shaft opposing portion 202 faces, with a gap between them, the cylindrical shaft end portion protruding from the base end portion 201. The shaft opposing portion 202 has a central ridge 203 and a pair of side ridges 204 on its inner peripheral surface. The central ridge 203 extends in the axial direction at approximately the center of the rotation direction on the inner peripheral surface. The side ridges 204 extend in the axial direction at positions sandwiching the central ridge 203 in the rotation direction on the inner peripheral surface. The fixing member 200 has an operating portion 205 that partially protrudes from the cylindrical peripheral surface on the outer periphery of the base end portion 201 and the shaft opposing portion 202. The operating portion 205 is not limited to a protruding shape and may be a concave shape as long as it is easy to operate.

Figure 4 is an explanatory diagram of the procedure for supporting the shaft member 118. Figure 4 shows a vertical cross section along the axis of the shaft member 118. The procedure progresses from the left figure, the left and right central figures, and the right figure. First, the fixing member 200 is positioned so that the opening of the shaft opposing portion 202 faces straight down, and the shaft end protruding from the base end portion 201 is above the inner surface 301 of the holding portion 300. Then, the shaft member 118 is lowered to place the shaft end on the inner surface 301 of the holding portion 300 (left and right central figure). In this state, the operating portion 205 of the fixing member 200 is operated to rotate the fixing member 200 180 degrees as shown by the arrow A in the figure, and the inner surface of the shaft opposing portion 202 faces the outer surface 302 of the holding portion 300.

Figure 5 is an explanatory diagram of the rotation of the shaft opposing portion 202 in the process from the left-right central view to the right view in Figure 4. The left view is a cross-sectional view taken along line XX in the left-right central view in Figure 4, and the right view is a cross-sectional view taken along line YY in the right view in Figure 4. The central protrusion 203 and the side protrusion 204 differ in the distance between the tip of the protrusion and the center of the arc of the semicircular hollow cylinder of the shaft opposing portion (hereinafter referred to as the radial distance from the arc center). Specifically, the central protrusion 203 has a shorter radial distance from the arc center than the side protrusion 204. The pair of side protrusions 204 have the same radial distance from the arc center.

The state changes from the left side of FIG. 5 to the center left and right sides and the right side as follows. When the fixed member 200 is rotated from the state shown in the left side, the shaft-facing portion 202 of the fixed member moves along the semicircular cylindrical outer surface 302 of the holding portion 300. During the rotation of the fixed member 200, the central protrusion 203, which has a short radial distance from the center of the arc, frictionally slides on the cylindrical outer surface of the holding portion 300, while the side protrusions 204, which have a long radial distance, do not come into contact with the outer surface 302 of the holding portion 300 (center left and right). The shaft-facing portion 202 deforms so that the central protrusion 203 comes into contact with the cylindrical outer surface of the holding portion 300 and the side protrusions 204 move away from the outer surface 302.

As the rotation of the fixed member 200 progresses, the central protrusion 203 with a short radial distance of the fixed member 200 enters the recess 303 on the outer circumferential surface 302 of the holding part 300, and the elastic force of the fixed member 200 causes the side protrusions 204 with a long radial distance to come into contact with the outer circumferential surface 302 of the holding part 300 (right diagram). In this state, the shaft member 118 of the secondary transfer device and the side protrusions 204 of the fixed member 200 sandwich the hollow cylindrical circumferential wall of the holding part 300 and fix it without any gaps. This ensures the positional accuracy of the shaft member 118.

As described above, the elastic force of the fixing member 200 sandwiches the hollow cylindrical peripheral wall of the holding part 300 between the shaft member 118 and the lateral protrusion 204 of the fixing member 200, and fixes the shaft member 118 without any gaps. In this fixed state, the elastic force of the fixing member 200 causes the lateral protrusion 204 to contact the outer circumferential surface 302 of the holding part 300, and applies a biasing force toward the inner surface 301 of the holding part 300 to the shaft member 118 via the base end 201 of the fixing member 200. As a result, the shaft member 118 cannot be detached from the holding part 300. On the other hand, in the rotational posture of the fixing member 200 in the state shown in the left diagram of FIG. 5, the fixing member 200 does not exert such a biasing force on the shaft member 118, and the shaft member 118 can be detached. Therefore, the fixed member 200 can be said to be a movable member that constitutes a biasing force applying means that applies a biasing force toward the holding part 300 to the end of the shaft member 118 to make it in an undetachable state, and releases the biasing force to make it in a detachable state.

The retaining portion 300 corresponds to the "other member" that the fixed member 200 abuts against when exerting a biasing force as a movable member. Specifically, the "abutment portion" of the retaining portion 300 that abuts against the outer peripheral surface 302 corresponds to the lateral protrusion 204.

Before moving from the state shown in the left diagram of FIG. 5 to the state shown in the center diagram, there is a period when only the lateral protrusion 204 on the downstream side in the rotation direction comes into contact with the outer circumferential surface 302 of the retaining portion 300. However, this period is short and the biasing force is relatively small, so there is little risk of wear. The biasing force is relatively small because, unlike the state shown in the right diagram of FIG. 5, the pair of contact points of the pair of lateral protrusions 204 do not surround the center of the shaft member 118.

2, in order to displace the secondary transfer roller shaft 107 upward by pushing it upward with the rotating arms 108 and 109, the roller support plate 103 needs to be able to rotate around the center of the shaft member 118 of the secondary transfer device. For this purpose, at least one of the following must be slidable: between the shaft member 118 and the roller support plate 103, between the shaft member 118 and the rotation center shaft members 116 and 117, and between the rotation center shaft members 116 and 117 and the rotating arm 108. For example, the rotation center shaft member 117 and the shaft member 118, and between the holding portion 300 of the rotation center shaft member 116 and the shaft member 118 are slidable. The engagement by the fixed member 200 can be set to a force that allows such sliding.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.
For example, the shaft support device of the present invention can be applied to shaft support devices other than transfer devices, as well as to shaft support devices of image forming devices, or to shaft support devices other than image forming devices.
The effects described in the embodiments of the present invention are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

The above description is merely an example, and the present invention provides unique effects for each of the following aspects.
(Aspect 1)
In a shaft support device that can selectively take an end of a shaft such as shaft member 118 between a removable state where the end is removable and a non-removable state where the end is not removable, the device includes a holding part such as holding part 300 that detachably holds the end, and a biasing force applying means such as fixed member 200 that applies a biasing force toward the holding part to the end to bring it into the non-removable state and releases the biasing force to bring it into the removable state. The biasing force applying means is configured using a movable member such as fixed member 200 that can selectively take a position in which the biasing force is exerted by contacting another member such as holding part 300, and a position in which the biasing force is not exerted. The device is characterized in that the abutting portion of the movable member with the other member, such as a lateral protrusion 204, is formed into a convex shape.

In the conventional device described in Patent Document 1, the rotating shaft is attached by covering a semi-circumferential surface of the rotating shaft with a support surface portion shaped to cover the semi-circumferential surface of the rotating shaft, and there is a possibility that a gap may occur between the support surface portion and the rotating shaft. This results in poor positional accuracy of the shaft in the attached state. In contrast, according to aspect 1, as described in the embodiment, a biasing force toward the holding portion is applied to the end of the shaft by the biasing force applying means, so that the occurrence of a gap that deteriorates the positional accuracy of the shaft can be prevented. Furthermore, since the contact portion of the movable member that contacts another member to exert the biasing force is made convex, the required range of machining accuracy can be limited to high accuracy, and deterioration of the positional accuracy of the shaft can be avoided.

Here, it is preferable that movable members such as the fixed member 200 are made of a resin material with high sliding properties, as this makes it easier to rotate the member. It is preferable that holding parts such as the holding part 300 are made of a metal material, as this provides the shaft with sufficient fixing strength and prevents wear caused by the sliding of the fixed member.

(Aspect 2)
In the shaft support device described in (Aspect 1), a movable member such as fixed member 200 has a base end such as base end 201 rotatably attached to a shaft such as shaft member 118, and is capable of selectively taking a rotation position where a contact portion such as lateral protrusion 204 abuts against a holding portion such as holding portion 300 from the opposite side to the end, and a rotation position where a contact portion such as lateral protrusion 204 does not abut against a holding portion such as holding portion 300. This allows for a simple configuration in which the movable member is rotatably attached to the shaft itself to be supported, unlike Patent Document 1 in which a portion that rotatably supports a base integral with the support surface portion in order to allow the support surface portion to rotate is provided in the bearing installation portion.

(Aspect 3)
In the shaft support device described in (Aspect 2), the shaft such as the shaft member 118 is cylindrical, the holding part such as the holding part 300 is hollow cylindrical with a part open for attaching and detaching the end of the shaft, and the movable member such as the fixed member 200 has abutting parts such as the side protrusions 204 abutting the outer surface of the peripheral wall of the hollow cylindrical shape, and the end of the shaft held on the inner surface of the peripheral wall such as the inner surface 301 and the abutting parts such as the side protrusions 204 sandwich the peripheral wall of the holding part 300 to apply a biasing force. According to this, since the end of the shaft is cylindrical and the holding part is hollow cylindrical, the inner holding surface and the outer surface where the abutting parts such as the side protrusions 204 abut are circular, which is a shape that is easy to achieve shape accuracy. Therefore, the positional accuracy of the shaft can be ensured without increasing manufacturing costs.

(Aspect 4)
In the shaft support device described in (Aspect 3), the movable member such as the fixed member 200 is characterized in that abutment portions such as lateral protrusions 204 are provided at two different locations in the rotation direction in opposing portions such as shaft opposing portions 202 that face each other at a distance on the outer surface of the peripheral wall of the holding portion 300. This makes it possible to stabilize the pressing and fixing by the convex abutment portions such as the lateral protrusions 204.

(Aspect 5)
In the shaft support device described in (Aspect 4), the two locations where the abutting portions of the lateral protrusions 204 or the like are provided are different from each other within a range of 80° to 160° in terms of the rotation angle of the movable member such as the fixed member 200. If the rotation angle is within this angle range, the pressing and fixing by the convex abutting portions of the lateral protrusions 204 or the like can be made more stable.

(Aspect 6)
In the shaft support device described in (Aspect 4), a movable member such as fixed member 200 has a convex shape such as central ridge 203 at a location between the two locations in the rotation direction at an opposing portion opposing the outer peripheral wall surface of a holding portion such as holding portion 300 with a gap therebetween, the distance between the tip and the center of the shaft in a state where the tip is not in contact with the outer peripheral wall surface is closer than that of abutting portions such as lateral ridge 204. The outer peripheral wall is also characterized by having a recess such as recess 303 into which the tip of the convex shape of central ridge 203 can fit, and the abutting portions of lateral ridge 204 can abut against the outer peripheral wall surface of a holding portion such as holding portion 300 with the tip of the convex shape of central ridge 203 fitted therein.

According to this, when the convex shape, which is closer than the contact portion of the lateral protrusion 204, etc., is in contact with the outer peripheral surface of the holding part, such as the holding part 300, the contact portion of the lateral protrusion 204, etc., can be separated from the outer peripheral surface. Therefore, wear due to rubbing of the contact portion of the lateral protrusion 204, etc. during rotation can be suppressed. In addition, since the convex shape of the central protrusion 203, etc., exists between the contact portions of the lateral protrusion 204, etc., provided at two different positions in the rotation direction of the opposing part, such as the shaft opposing part 202, the contact portions of the lateral protrusion 204, etc., provided at two positions can be separated from the outer peripheral surface by the same amount. Furthermore, when the convex shape of the central protrusion 203, etc., fits into the recessed portion, such as the recessed portion 303, provided on the outer peripheral surface, such as the outer peripheral surface 302, which is the sliding surface, in the attached state, the operator can be made aware of the change in sensation and can feel the attached state.

(Aspect 7)
In the shaft support device described in (Aspect 3), the movable member such as the fixed member 200 has a convex shape such as a central protrusion 203, which is located at a position different from the abutment parts such as the side protrusions 204 in the rotation direction at the opposing part facing the outer wall surface of the holding part such as the holding part 300 at a distance, and the distance relationship between the tip and the center of the shaft in a state where it is not in contact with the outer wall surface of the peripheral wall is closer than that of the abutment parts such as the side protrusions 204. Also, the outer surface part of the peripheral wall has a recess such as a recess 303 into which the tip of the convex shape of the central protrusion 203 can enter, and the abutment parts of the side protrusions 204 can abut against the outer wall surface of the holding part such as the holding part 300 when the tip of the convex shape of the central protrusion 203 enters. According to this, as described above in (Aspect 6), wear due to friction of the abutment parts of the side protrusions 204 during rotation can be suppressed. Also, the operator can feel the wearing state by the change in the feeling when fitting into the recess.

(Aspect 8)
In a shaft support device that can selectively take an end of a shaft such as shaft member 118 between a detachable state in which the end is detachable and an undetachable state in which the end is not detachable, a holding part such as holding part 300 that detachably holds the end, and a biasing force applying means such as fixed member 200 that applies a biasing force toward the holding part to the end to bring it into the undetachable state and releases the biasing force to bring it into the detachable state are provided. The biasing force applying means is configured using a movable member such as fixed member 200 that can selectively take a position in which the biasing force is exerted by contacting another member such as holding part 300, and a position in which the biasing force is not exerted. A movable member such as fixed member 200 has a base end such as base end 201 rotatably attached to a shaft such as shaft member 118, and is capable of selectively taking a rotation position where an abutting portion such as lateral protrusion 204 with another member such as holding portion 300 abuts against a holding portion such as holding portion 300 from the opposite side to the shaft end, and a rotation position where an abutting portion such as lateral protrusion 204 does not abut against a holding portion such as holding portion 300. This allows for a simple configuration in which the movable member is rotatably attached to the shaft itself that is to be supported, as described above in (Aspect 2).

(Aspect 9)
A transfer device that is detachable from an image forming apparatus main body is characterized in that it is provided with a shaft for positioning with respect to the image forming apparatus main body, and the shaft support device described in any one of (Aspects 1 to 8) is used to support the positioning shaft. This makes it possible to provide a transfer device that has high fixing positioning accuracy and good detachability.

(Aspect 10)
In an image forming apparatus equipped with a transfer device, the transfer device described in (aspect 9) is used as the transfer device. This makes it possible to achieve both high-quality images with stable transfer performance in the image forming apparatus and improved ease of removal of the transfer device.

1: Image forming unit 2: Photoconductor 3: Drum cleaning device 6: Charging device 8: Development device 30: Transfer unit 31: Intermediate transfer belt 32: Drive roller 33: Secondary transfer back roller 34: Cleaning backup roller 35: Primary transfer roller 37: Pre-transfer roller 40: Secondary transfer device 41: Secondary transfer roller 42: Separation roller 43: Driven roller 44: Drive roller 45: Stop roller 46: Tension roller 60: Cassette 60a: Roller 61: Registration roller pair 65: Transport path 90: Fixing device 91: Heating roller 92: Pressure roller 93: Fixing roller 94: Fixing belt 95: Tension roller 96: Support roller 100: Printer 101: Optical writing unit 102: Secondary transfer belt 103: Roller support plate 107: Secondary transfer roller shaft 108: Rotating arm 109: Rotating arm 110 : Contact surface 111 : Contact surface 113 : Drawer housing 114 : Spring 115 : Spring 116 : Rotational center shaft member 117 : Rotational center shaft member 118 : Shaft member 200 : Fixed member 201 : Base end portion 202 : Shaft facing portion 203 : Central protrusion 204 : Side protrusion 205 : Operation portion 300 : Holding portion 301 : Inner surface 302 : Outer circumferential surface 303 : Recess 406 : Secondary transfer belt A : Arrow N2 : Secondary transfer nip P : Recording material T : Toner image a : Belt movement direction b : Recording material conveyance direction

JP 2001-271826 A

Claims (10)

A shaft support device capable of selectively taking a removable state in which an end of a shaft is removable and a non-detachable state in which the end is non-detachable,
a holding portion that detachably holds the end portion; and a biasing force applying means that applies a biasing force toward the holding portion to the end portion to bring the end portion into the non-detachable state and releases the biasing force to bring the end portion into the detachable state,
the biasing force applying means is configured using a movable member that can selectively take a position in which the biasing force is exerted by contacting another member and a position in which the biasing force is not exerted,
A shaft support device according to claim 1, wherein the movable member has a contact portion with the other member, the contact portion being formed in a convex shape. 2. The shaft support device according to claim 1,
The movable member is characterized in that its base end is rotatably attached to the shaft, and is capable of selectively taking a rotational position in which the abutment portion abuts against the holding portion from the opposite side to the end, and a rotational position in which the abutment portion does not abut against the holding portion. 3. The shaft support device according to claim 2,
The shaft is cylindrical;
The holding portion has a hollow cylindrical shape with a portion open for attachment and detachment of the end portion,
The movable member abuts the abutment portion against the outer surface of the hollow cylindrical peripheral wall, and clamps the peripheral wall between the end held on the inner surface of the peripheral wall and the abutment portion to apply the biasing force. 4. The shaft support device according to claim 3,
The movable member has a contact portion at each of two different positions in a rotation direction on an opposing portion of the outer surface of the peripheral wall that faces the outer surface of the peripheral wall with a gap therebetween. 5. The shaft support device according to claim 4,
The shaft support device is characterized in that the two locations are different from each other within a range of 80° to 160° in terms of the rotation angle of the movable member. 5. The shaft support device according to claim 4,
The movable member has a convex shape at a location between the two locations in the rotation direction at an opposing portion that faces the outer surface of the peripheral wall with a gap between them, and the distance between the tip and the center of the shaft when not in contact with the outer surface of the peripheral wall is closer than that of the abutment portion, and the outer surface of the peripheral wall has a recess into which the tip of the near convex shape can fit, and when the tip of the near convex shape is fitted into the recess, the abutment portion can abut against the outer surface of the peripheral wall. 4. The shaft support device according to claim 3,
the movable member has a convex shape at a location different from the abutment portion in a rotation direction at a facing portion facing the outer surface of the peripheral wall with a gap therebetween, the convex shape having a distance relationship between a tip end and a center of the shaft in a state where the tip end is not in contact with the outer surface of the peripheral wall and is closer than the abutment portion;
A shaft support device characterized in that the outer surface of the peripheral wall has a recess into which the tip of the near convex shape can fit, and when the tip of the near convex shape is fitted, the abutment portion can abut against the outer surface of the peripheral wall. A shaft support device capable of selectively taking a detachable state in which an end of a shaft is detachable and a non-detachable state in which the end is non-detachable,
a holding portion that detachably holds the end portion; and a biasing force applying means that applies a biasing force toward the holding portion to the end portion to bring the end portion into the non-detachable state and releases the biasing force to bring the end portion into the detachable state,
the biasing force applying means is configured using a movable member that can selectively take a position in which the biasing force is exerted by contacting another member and a position in which the biasing force is not exerted,
The movable member is characterized in that its base end is rotatably attached to the shaft, and is capable of selectively taking a rotational position in which its abutment portion with the other member abuts against the holding portion from the opposite side to the end, and a rotational position in which the abutment portion does not abut against the holding portion. In a transfer device detachable from an image forming apparatus body,
9. A transfer device comprising a shaft for positioning relative to a main body of an image forming apparatus, the shaft support device according to claim 1 being used to support the shaft for positioning. In an image forming apparatus equipped with a transfer device,
10. An image forming apparatus comprising the transfer device according to claim 9.

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