JP2010197720A - Electrical contact structure and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical contact structure where an elastic deformation area is sufficiently taken and a contact failure can be prevented, and to provide an image forming apparatus. <P>SOLUTION: In the electrical contact structure A provided with a contact member 100 in which one end part 100A is fixed to an electrically grounded frame 120, the other end part 100B elastically deformed with one end part 100A as a starting point is brought into contact with the end part of a rotary shaft 110 freely rotatably supported around the shaft in an axial direction so as to take an electrical contact, a turning regulation part 140 regulating the turning of the other end part 100B with one end part 100A along a plane orthogonal to the axial direction as the center while achieving the elastic deformation in the axial direction with one end part 100A as a starting point is provided to the space of the elastically deformed area W of the contact member 100 from the contact position of one end part 100A to the fixing position of the other end part 100B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrical contact structure and an image forming apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as printers, copiers, facsimiles, and multifunction machines equipped with these functions have been provided with a rotating body using an electrical action such as a photosensitive drum or a developing roller. These rotary bodies are in contact with a contact member fixed to a frame or the like in the axial direction in order to take an electrical ground (ground) (see, for example, Patent Document 1 and Patent Document 2). ). The contact member is attached in a state of being elastically deformed in the axial direction so as to prevent contact failure with respect to the end portion of the rotating shaft, and expresses a predetermined contact pressure.

  FIG. 6 is an example showing a conventional electrical contact structure. As shown in the figure, the rotating shaft 210 of the rotating body is rotatably supported via a bearing 221 fixed to the frame 220. The contact member 200 is fixed to the frame 220 by a screw member 230 having one end portion 200A inserted in the axial direction, and the other end portion 200B having a slit in the center is elastically deformed to be connected to the end portion 210A of the rotating shaft 210. Axial contact.

  The frame 220 is formed with a pair of protrusions 222 protruding in the axial direction at positions sandwiching the position of the screw member 230. The protrusion 222 is engaged with the opening 202 formed in the one end 200A of the contact member 200, thereby positioning the center position of the other end 200B. Thereby, the shift | offset | difference of the center position of the other end part 200B which contacts with the rotating end part 210A and receives force is suppressed.

JP-A-6-83123 JP-A-10-105022

  By the way, in the said electrical contact structure, the elastic deformation area | region (between a fixed position and a contact position) of the contact member 200 is taken wide in order to make the contact pressure of the other end part 200B act uniformly and stably. However, when the distance between the fixed position and the contact position increases, a minute gap (inevitable gap between the opening 202 and the protrusion 222) exists in the positioning portion, and thus the rotating end portion 210A. The other end portion 200B that receives the force from is easily rotated along a plane orthogonal to the axial direction. Then, as shown in FIG. 7, even if the center position of the other end portion 200B is shifted and no slit is provided even if a slit is provided, or even if the contact is made at two points, there is a difference in contact pressure. This causes contact failure.

  The present invention has been made in view of the above problems, and an object thereof is to provide an electrical contact structure and an image forming apparatus capable of taking a sufficient elastic deformation region and preventing contact failure.

In order to solve the above-mentioned problems, the present invention has one end portion electrically connected to a fixed portion and fixed, and the other end portion elastically deformed from the one end portion as a starting point is rotatably supported around an axis. An electrical contact structure comprising a contact member that contacts the end of the rotating shaft in the axial direction to make an electrical connection, from the contact position of the one end to the fixed position of the other end Between the elastic deformation regions of the contact member up to the above, the other centered on the one end portion along the plane orthogonal to the axial direction while allowing the elastic deformation in the axial direction starting from the one end portion A configuration is adopted in which a rotation restricting portion that restricts the rotation of the end portion is provided.
By adopting this configuration, in the present invention, by providing the rotation restricting portion between the elastic deformation regions of the contact member, the rotation of the other end of the contact member can be restricted at a position closer to the contact position. For this reason, it is suppressed that the gap | deviation width of an other end part becomes large, and a contact failure can be prevented.

In the present invention, the rotation restricting portion includes a protrusion protruding from the contact member in the axial direction, the protrusion being movably inserted in the axial direction, and the inserted protrusion. The structure which has the latching groove part which latches the said rotation direction both sides with a side wall is employ | adopted.
By adopting this configuration, in the present invention, the contact member can be elastically deformed freely in the axial direction, and the protrusion is locked by the side wall of the locking groove on both sides in the rotation direction. The rotation is restricted.

Moreover, in this invention, the structure that the stopper which latches with the said locking groove part in the predetermined position in the said axial direction is provided in the front-end | tip part of the said protrusion part is employ | adopted.
By adopting this configuration, in the present invention, when the contact member is elastically deformed in the axial direction, the protruding portion is prevented from coming off from the locking groove portion.

In the present invention, a configuration is adopted in which the predetermined position is in a range not exceeding the limit of the elastic deformation in the axial direction of the contact member.
By adopting this configuration, in the present invention, even if the rotating shaft pushes the contact member in the axial direction more than necessary, the stopper is locked by the locking groove before the contact member is plastically deformed. Deformation can be suppressed.

Moreover, in this invention, the said contact member is formed from a sheet metal, and the structure that the said protrusion part cuts and raises a part of said sheet metal is employ | adopted.
By adopting this configuration, in the present invention, the protruding portion can be formed at a low cost without increasing the number of parts.

  In the present invention, the image forming apparatus having the electrical contact structure described above is used.

  Further, in the present invention, the end of the rotating shaft is fixed to a grounded portion whose one end is electrically grounded, and the other end that is elastically deformed from the one end as a starting point is rotatably supported around the axis. Is provided with an earth ground structure including a contact member that is brought into electrical contact with the above-described axial direction, and the image forming apparatus including the above-described electric contact structure is used as the ground ground structure.

According to the present invention, the end portion of the rotating shaft is supported by the other end portion that is elastically deformed with the one end portion electrically connected to the fixed portion and is elastically deformed starting from the one end portion. An electrical contact structure comprising a contact member that makes an electrical connection by making contact with the shaft in the axial direction, and the elasticity of the contact member from the contact position of the one end to the fixed position of the other end Between the deformation areas, the rotation of the other end portion around the one end portion along the plane orthogonal to the axial direction is restricted while allowing the elastic deformation in the axial direction starting from the one end portion. By adopting the configuration in which the rotation restricting portion is provided, the rotation of the other end portion of the contact member can be restricted at a position closer to the contact position. For this reason, it is suppressed that the gap | deviation width of an other end part becomes large, and a contact failure can be prevented.
Therefore, according to the present invention, there is an effect that it is possible to provide an electrical contact structure capable of taking a sufficient elastic deformation region and preventing contact failure.

1 is a schematic diagram illustrating a configuration of a printer according to an embodiment of the present invention. It is a perspective view which shows the electrical contact structure in embodiment of this invention. It is the front view and sectional side view which show the structure of the electrical contact structure in embodiment of this invention. It is a figure explaining the effect | action of the rotation control part in embodiment of this invention. It is a figure explaining the effect | action of the stopper in embodiment of this invention. It is a figure explaining the conventional electrical contact structure. It is a figure explaining the conventional electrical contact structure.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description, an example in which the electrical contact structure of the present invention is applied to a printer (image forming apparatus) will be described. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

First, the configuration of the printer P in the present embodiment will be described with reference to FIG.
FIG. 1 is a schematic diagram illustrating a configuration of a printer P according to an embodiment of the present invention.
As shown in FIG. 1, the printer P transfers an image formed on the sheet material, an image forming unit 2 that forms an image on the sheet material, a paper feed cassette 3 that accommodates the sheet material, and the sheet material. A secondary transfer unit 4 that performs fixing, a fixing unit 5 that fixes the transferred image onto the sheet material, a paper discharge tray 6 that receives the discharged and completed sheet material, and a paper discharge tray 6 from the paper feed cassette 3. And a conveyance path 7 for conveying the sheet material.

The image forming unit 2 includes a belt unit 20, a cleaning unit 30, and image forming units F (FY, FM, and F) corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (BK). FC, FB).
The belt unit 20 includes an intermediate transfer belt 21 to which an image is transferred from the image forming unit F, and a driving roller 22, a driven roller 23, and a tension roller 24 that are installed on the intermediate transfer belt 21 and run endlessly. The tension roller 24 is provided with a biasing device 25 having a spring mechanism.
The cleaning unit 30 includes a cleaning roller, a cleaning blade, and the like, and is configured to remove toner remaining on the intermediate transfer belt 21.

The image forming unit F includes a photosensitive member (rotating member) 10, a charger 11, an exposure device 12, and a developing device 13, and further includes a cleaning device and a charge removal device (not shown). Further, the image forming unit F is configured to perform primary transfer with the primary transfer roller 14 attached to the belt unit 20.
The photoconductor 10 is formed in a cylindrical shape, and an electrostatic latent image and a toner image based on the electrostatic latent image are formed on the peripheral surface thereof. The charger 11 is disposed so as to face the photoconductor 10 and charges the peripheral surface of the photoconductor 10. The exposure device 12 scans the peripheral surface of the charged photoconductor 10 with laser light emitted based on image data in the print format. The developing device 13 develops an image based on the electrostatic latent image on the peripheral surface of the photoconductor 10 by supplying toner to the peripheral surface of the photoconductor 10. The primary transfer roller 14 is disposed opposite to the photoconductor 10 with the intermediate transfer belt 21 interposed therebetween, and primarily transfers an image developed on the photoconductor 10 to the intermediate transfer belt 21.

The paper feed cassette 3 can be pulled out with respect to the apparatus main body and accommodates a sheet material.
The secondary transfer unit 4 performs secondary transfer of an image formed on the intermediate transfer belt 21 onto a sheet material. The secondary transfer unit 4 sandwiches the drive roller 22 that drives the intermediate transfer belt 21 and the intermediate transfer belt 21 therebetween. A secondary transfer roller 41 disposed opposite to the driving roller 22 is provided.
The fixing unit 5 fixes the image secondarily transferred on the sheet material, and includes a heating roller 51 that fixes the toner by pressing and heating.
The conveyance path 7 includes a pickup roller 71 that carries out the sheet material from the paper feed cassette 3, a paper feed roller 72 that conveys the sheet material, and a paper discharge roller 73 that discharges the sheet material to the paper discharge tray 6.

Next, the configuration of the electrical contact structure A that takes electrical grounding of the photoconductor 10 will be described with reference to FIGS.
FIG. 2 is a perspective view showing the electrical contact structure A in the embodiment of the present invention. FIG. 3 is a front view and a cutaway side view showing the configuration of the electrical contact structure A in the embodiment of the present invention.
The electrical contact structure A is for electrically grounding the rotating shaft 110 of the photoconductor 10, and is made of a metal that supports the contact member 100 and the contact member 100 that contacts the end 110A of the rotating shaft 110 in the axial direction. It has a frame (fixed part, grounding part) 120 and a rotation restricting part 140 that restricts the rotation of the contact member 100. The electrical contact structure A constitutes an earth grounding structure in which the contact member 100 and the rotating shaft 110 are brought into contact with each other so that the photoreceptor 10 is electrically grounded to prevent an increase in base potential and residual potential.

  The frame 120 is electrically grounded (regardless of direct grounding or indirect grounding), and rotatably supports the rotating shaft 110 of the photoreceptor 10 via a bearing 121. The end 110A of the rotating shaft 110 of the present embodiment has a tapered shape that gradually decreases in diameter in the axial direction, and extends through the frame 120 to the outside (hereinafter referred to as the frame outside). In this frame 120, an opening (engagement groove) 142 (described later) and a protrusion 122 are sequentially spaced from each other at a predetermined interval in a predetermined direction orthogonal to the axial direction of the rotating shaft 110 from the position where the bearing 121 is provided. Is formed.

  The contact member 100 is made of a spring plate that is conductive and elastically deformable. In the present embodiment, a stainless steel plate or a phosphor bronze plate having a predetermined hardness is used for the purpose of securing contact pressure and preventing deformation due to force received when the rotation is restricted.

One end portion 100A of the contact member 100 is fixed to the frame 120 by a screw member 130 inserted in the axial direction. Further, the other end portion 100B of the contact member 100 extends in a predetermined direction from the one end portion 100A toward the end portion 110A of the rotating shaft 110, and the center portion thereof corresponds to the tapered shape of the end portion 110A. A slit 100B1 is formed. Further, the one end portion 100A is formed with an opening portion 100A1 that opens in a circular shape. The opening portion 100A1 is engaged with a substantially cylindrical protrusion portion 122 that protrudes in the axial direction outside the frame. The center position of the end portion 100B is positioned.
The contact member 100 has a shape that bends in the predetermined direction at a predetermined height in the axial direction in the vicinity of the fixed position. The bent height of this shape is set according to the amount of protrusion of the rotating shaft 110 to the outside of the frame.

In the contact member 100 having the above-described configuration, the other end portion 100B elastically deformed in the axial direction outside the frame starting from the one end portion 100A is contacted in the axial direction so that the one end portion 110A of the rotating shaft 110 and the slit 100B1 are fitted. And take an electrical ground.
In the following description, the distance from the fixed position where the one end 100A of the contact member 100 is fixed by the screw member 130 to the contact position where the other end 100B of the contact member 100 contacts the end 110A of the rotating shaft 110 is described. Is referred to as an elastic deformation region W (see FIG. 3B).

  The rotation restricting portion 140 restricts the rotation of the other end portion 100B around the one end portion 100A along the plane orthogonal to the axial direction between the elastic deformation regions W, and includes a projecting portion 141 and an opening. Part 142. The rotation restricting portion 140 in the present embodiment is configured to restrict the rotation at a substantially middle position of the elastic deformation region W.

  The protruding portion 141 protrudes from the contact member 100 in the axial direction inside the frame, and is inserted into an opening 142 formed in the frame 120 so as to be movable in the axial direction. The protruding portion 141 is formed by cutting and raising a part of the contact member 100. As a result, the protruding portion 141 can be formed at a low cost without increasing the number of components. The protruding portion 141 has a stopper 141a whose tip is bent in a predetermined direction, and is configured to be locked between the edge of the opening 142 at a position inside the frame in the axial direction.

  The opening 142 penetrates the frame 120 in the axial direction and opens in a substantially rectangular shape. The opening 142 has a width corresponding to the protrusion 141, and is configured to restrict both sides of the protrusion 141 inserted in the opposite side wall 142a in the rotational direction. Note that there is a minute gap between the protruding portion 141 and the opening 142 in the direction in which the side wall 142a faces.

Next, the operation of the electrical contact structure A including the rotation restricting portion 140 having the above configuration will be described with reference to FIGS. 4 and 5.
FIG. 4 is a diagram illustrating the operation of the rotation restricting unit 140 according to the embodiment of the present invention. FIG. 5 is a diagram for explaining the operation of the stopper 141a in the embodiment of the present invention.

  In the electric contact structure A, the rotating shaft 110 has the other end portion 100B elastically deformed with the one end portion 100A of the contact member 100 as a starting point in order to electrically ground the rotating shaft 110 of the photosensitive member 10 that is rotatably supported. It is made to contact with 110 A of edge parts of an axial direction. Here, since the protrusion 141 is inserted into the opening 142 so as to be movable in the axial direction, the elastic deformation in the axial direction is not hindered in providing this configuration. In the electrical contact structure A having the above configuration, the elastic deformation region W of the contact member 100 is wide for the purpose of causing the contact pressure of the other end portion 100B to act uniformly and stably.

  As shown in FIG. 4A, when the rotating shaft 110 rotates around the axis, the other end portion 100B receives a force and is orthogonal to the axial direction centering on the one end portion 100A (more specifically, the mounting position of the screw member 130). Try to rotate along the plane. The rotation restricting unit 140 restricts this rotation between the elastic deformation regions W. More specifically, the protrusion 141 protruding in the axial direction from the contact member 100 comes into contact with one of the side walls 142a of the opening 142 formed in the frame 120 to be locked, and this rotation is restricted. . Since there is only a minute gap between the protrusion 141 and the side wall 142a, both sides of the protrusion 141 in the rotational direction can be locked at a minute distance (see FIG. 4B). For this reason, the contact position of the other end portion 100B does not greatly deviate, and even if the slit 100B1 is provided, there is a difference in contact pressure even when the contact is not made at two points or when the contact is made at two points. , Contact failure is prevented.

  That is, when the elastic deformation region W is widened, there is a minute gap between the opening 100A1 and the protrusion 122. Therefore, the distance from the other end 100B is long only by the configuration of the rotation restriction. As a result, the displacement width of the contact position of the other end 100B becomes wide. On the other hand, by providing the rotation restricting portion 140 at a position close to the other end portion 100B between the elastic deformation regions W as in the present embodiment, it is possible to narrow the deviation width of the contact position of the other end portion 100B. it can. In addition, the rotation restricting portion 140 restricts the rotation along the plane orthogonal to the axial direction while allowing the elastic deformation in the axial direction, so that the positioning can be performed while maintaining a predetermined contact pressure. It becomes.

  In addition, a stopper 141a is provided at the tip of the protruding portion 141. As shown in FIG. 5, even if the rotating shaft 110 attempts to push the contact member 100 in the axial direction more than necessary, the protruding portion 141 is opened. Since it contacts and locks the edge portion of the portion 142, the protruding portion 141 is prevented from coming out of the opening portion 142 when the contact member 100 is elastically deformed in the axial direction. Further, if the stopper 141a is provided within a range that does not exceed the elastic deformation limit in the axial direction of the contact member 100, the stopper 141a hits the frame 120 before the contact member 100 exceeds the elastic deformation limit. Can be suppressed.

Therefore, according to the above-described embodiment, the one end portion 100A is fixed to the electrically grounded frame 120, and the other end portion 100B elastically deformed from the one end portion 100A as a starting point is rotatably supported around the axis. An electrical contact structure A including a contact member 100 that is brought into electrical contact with an end portion of the rotating shaft 110 that is in an axial direction, from a contact position of one end portion 100A to a fixed position of the other end portion 100B. Between the elastic deformation regions W of the contact member 100 until the other end portion centering on the one end portion 100A along the plane orthogonal to the axial direction while allowing the elastic deformation in the axial direction starting from the one end portion 100A. By adopting a configuration in which a rotation restricting portion 140 that restricts the rotation of 100B is provided, the other end portion 100B of the contact member 100 can be rotated at a position closer to the contact position. It can control. For this reason, it is suppressed that the gap | deviation width of the other end part 100B becomes large, and a contact failure can be prevented.
Therefore, according to this embodiment, there is an effect that it is possible to provide the electrical contact structure A that can take a sufficient elastic deformation region and prevent contact failure. Further, there is an effect that it is possible to provide a printer P that can prevent contact failure and perform stable image forming processing without causing image defects.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, the rotation restricting portion is not limited to the above-described configuration, and may be configured such that a slit is provided in the contact member and a pin inserted through the slit is erected on the grounding portion. In this case, the width of the slit is preferably substantially the same as the outer shape of the pin. Furthermore, in order to prevent the pin of the contact member from being pulled out, the pin head (tip portion) may have a diameter larger than the slit width and used as a stopper. Note that the length of the slit is preferably set to such a length that the pin does not interfere with the rotation because the contact member is deformed so as to rotate when elastically deforming in the axial direction.

  Further, for example, the electrical grounding structure including the contact member can be applied to, for example, bias application in addition to electrical grounding.

  A ... electric contact structure, P ... printer, W ... elastic deformation region, 100 ... contact member, 100A ... one end, 100B ... other end, 110 ... rotating shaft, 120 ... frame (fixed part, grounding part), 140 ... Rotation restricting part, 141 ... Projection part, 142 ... Opening part (locking groove part), 142a ... Side wall

Claims (7)

One end portion is electrically connected to the fixed portion and fixed, and the other end portion, which is elastically deformed from the one end portion as a starting point, is in the axial direction with respect to the end portion of the rotating shaft that is rotatably supported around the axis. It is an electrical contact structure comprising a contact member that makes electrical connection by contacting with
While allowing the elastic deformation in the axial direction starting from the one end, between the elastic deformation region of the contact member from the contact position of the one end to the fixed position of the other end, the shaft An electrical contact structure characterized in that a rotation restricting portion for restricting rotation of the other end portion around the one end portion along a plane orthogonal to the direction is provided. The rotation restricting portion is a protruding portion protruding in the axial direction from the contact member;
2. The protrusion according to claim 1, wherein the protrusion is inserted movably in the axial direction, and has a locking groove that locks both sides of the inserted protrusion in the rotation direction with side walls. Electric contact structure.   The electrical contact structure according to claim 2, wherein a stopper that locks the locking groove at a predetermined position in the axial direction is provided at a tip of the protruding portion.   The electrical contact structure according to claim 3, wherein the predetermined position is within a range that does not exceed a limit of the elastic deformation in the axial direction of the contact member. The contact member is formed of sheet metal;
5. The electrical contact structure according to claim 2, wherein the protruding portion is formed by cutting and raising a part of the sheet metal.   An image forming apparatus comprising the electrical contact structure according to claim 1. One end is fixed to a grounded portion that is electrically grounded, and the other end, which is elastically deformed from the one end as a starting point, is in the axial direction with respect to the end of the rotating shaft that is rotatably supported around the axis. It has an earth ground structure with a contact member that takes electrical ground by contacting with
The image forming apparatus according to claim 6, wherein the ground contact structure includes the electrical contact structure.

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