JP2006071692A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a sheet from being caught between junction parts due to attachment/detachment of a transfer belt unit in an image forming apparatus in which the transfer belt unit is attached to an apparatus main body so as to be attachable and detachable in the same/opposite direction as/to a sheet conveyance direction by the transfer belt unit and a connection member for receiving electric supply from the apparatus main body is provided at an apparatus main body-side tip end in an attaching and detaching direction of the transfer belt unit. <P>SOLUTION: Covering members 33a, 33b and covering members 27a, 27b are provided so as to cover a connector 32 provided at the transfer belt unit 3 and a connector 26 provided at the apparatus main body 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus in which a transfer belt unit is attached to an apparatus main body so as to be detachable in the same / reverse direction as a sheet conveying direction by the transfer belt unit.

  In an apparatus for forming a full color image by electrophotography, for example, a toner image formed on the surface of a photosensitive drum with toners of various colors such as black toner, cyan toner, magenta toner, and yellow toner is transferred onto a predetermined sheet. To form a full-color transfer image. Then, a sheet having such a transferred image is introduced into a fixing roller disposed on the paper discharge side of the transfer belt, and the transferred image is fixed on the sheet to form an image.

  As one of such full-color image forming apparatuses, a dedicated photosensitive drum is used for each color toner, and the photosensitive drum is stretched between a pair of belt driving rollers and transferred for paper conveyance. A so-called tandem type full-color image forming apparatus juxtaposed on a belt has been put into practical use. This tandem full-color image forming apparatus has an advantage that image formation can be performed while a sheet is continuously conveyed by a transfer belt.

  In such a tandem full-color image forming apparatus, a toner image is formed for each of the plurality of photosensitive drums arranged on the transfer belt, and therefore, the tensioned transfer belt is placed above the transfer belt. A plurality of transfer rollers are arranged to face each of the plurality of arranged photosensitive drums. While applying a bias voltage having a polarity opposite to the charging polarity of the toner image to a transfer roller disposed opposite to each photoconductor drum with the transfer belt interposed therebetween, the sheet is transferred to the photoconductor drum and the transfer roller by the transfer belt. , The toner image of a predetermined color formed on each photosensitive drum is transferred onto the paper.

In general, the transfer belt and the transfer roller described above are unitized and incorporated into an image forming apparatus such as a copying machine as a transfer belt unit. For example, as shown in FIG. 6, such a transfer belt unit 3 is detachable in the same / reverse direction as the sheet conveying direction by the transfer belt unit, and is a connector for receiving electric supply from the image forming apparatus main body 1. A (connecting member) 32 provided at the front end of the transfer belt unit 3 on the apparatus main body side is known.
JP 2003-341879 A (Claims)

  In the image forming apparatus having the above-described configuration, as shown in FIG. 6, when paper conveyance is stopped due to a paper jam or the like, a connecting portion D between the connector 26 on the apparatus main body 1 side and the connector 32 on the transfer belt unit 3 side. When the transfer belt unit 3 is pulled out from the apparatus main body 1, the sheet P is pulled out together with the transfer belt unit 3, and the sheet P is pulled out. The front portion is in a state of hanging from the leading end of the transfer belt unit 3 ((b) in the figure). If the transfer belt unit 3 is attached to the apparatus main body 1 in this state, the hanging paper P is sandwiched between the connector 32 and the connector 26, and it becomes impossible to supply electricity to the transfer belt unit 3. (FIG. (C)). This similarly occurs when the transfer belt unit 3 is pulled out from the apparatus main body 1 and is not pulled out together with the transfer belt unit 3 and the paper P remains on the apparatus main body side.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is when the paper is stopped while straddling the connecting portion when the paper conveyance is stopped by a jam or the like. However, it is to prevent the sheet from being caught in the connecting portion by attaching and detaching the transfer belt unit.

  In order to achieve the above object, in the image forming apparatus of the present invention, the transfer belt is so covered as to cover the first connection member provided in the transfer belt unit and the second connection member provided in the apparatus main body in a front view. The first cover member and the second cover member are provided on the unit and the apparatus main body.

  The first cover is provided so that the end of the sheet hanging from the transfer belt unit or the apparatus main body is lifted upward from the connecting portion between the first connection portion and the second connection portion when the transfer belt unit is mounted. Each of the member and the second cover member is provided with a comb-like portion inclined downward toward the free end side, and the cover member is arranged so that the comb-like portion is engaged when the transfer belt unit is mounted on the apparatus body. It is preferable to attach.

  Moreover, it is preferable that at least one of a 1st cover member and a 2nd cover member has flexibility from a viewpoint of the dimensional accuracy in a shaping | molding, and a storage property.

  In the image forming apparatus of the present invention, when viewed from the front, the transfer belt unit and the apparatus main body have the first connection member provided on the transfer belt unit and the second connection member provided on the apparatus main body so as to cover the first connection member. Since the cover member and the second cover member are provided, the paper conveyance is stopped due to a jam or the like, and the transfer belt unit is pulled out from the apparatus main body, so that the end of the paper hangs down from the transfer belt unit or the apparatus main body. Even in this case, the first cover member and the second cover member can prevent the sheet from being caught in the connecting portion.

  Also, the first cover member and the second cover member are provided with comb-like portions inclined downward toward the free end side so that the comb-like portions are engaged when the transfer belt unit is mounted on the apparatus body. When the cover member is attached, when the transfer belt unit is mounted, the end portion of the paper hanging from the transfer belt unit or the apparatus main body is lifted upward from the connecting portion. This reliably prevents the sheet from being caught in the connecting portion. In addition, when at least one of the first cover member and the second cover member is flexible, tolerance in dimensional accuracy is generated and the space can be stored in a narrow space.

  Hereinafter, the image forming apparatus of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to these embodiments. FIG. 1 is a schematic longitudinal sectional view showing an internal configuration of a color printer (image forming apparatus) showing an embodiment of an image forming apparatus of the present invention. A sheet storage unit 16 that can store a plurality of sheets is disposed below the color printer. The paper storage unit 16 is provided with a pickup roller 18 for feeding the stored paper one by one to the paper transport path 17 side. The sheet fed by the pickup roller 18 is guided to the sheet conveyance path 17 via the paper feed roller 19 and conveyed upward by the conveyance roller 20 toward the registration roller 21 disposed at the end portion of the sheet conveyance path 17. Is done.

  The registration roller 21 is disposed upstream of the transfer belt 31 in the sheet conveyance direction, and the leading edge of the sheet conveyed from the sheet storage unit 16 through the sheet conveyance path 17 reaches the registration roller 21. At that time, the conveyance is temporarily stopped. Then, the sheet is conveyed to the image forming units 2M, 2C, 2Y, and 2B at a timing that will be described later.

  The image forming section of the color printer 1 has a so-called tandem structure, and four image forming units 2M, 2C, 2Y, and 2B for forming magenta, cyan, yellow, and black single-color images are provided. Along the straight conveyance path formed on the upper surface of the transfer belt unit 3, they are arranged in a line in this order from the upstream side in the sheet conveyance direction.

  Each of the four image forming units 2M, 2C, 2Y, and 2B includes photosensitive drums 4M, 4C, 4Y, and 4B that rotate clockwise in FIG. The photosensitive drums 4M, 4C, 4Y, and 4B are arranged in parallel with each other with their respective axes extending in the horizontal direction perpendicular to the paper transport direction A. Each photosensitive drum 4M, 4C, 4Y, 4B is uniformly charged by the discharge of the main chargers 5M, 5C, 5Y, 5B. Then, based on the color image data of magenta, cyan, yellow, and black color components of image data input from an external device (not shown) such as a microcomputer connected to the color printer 1, the LED print head 6M. , 6C, 6Y and 6B are exposed to light. Thereby, so-called electrostatic latent images are formed on the surfaces of the photosensitive drums 4M, 4C, 4Y, and 4B.

  In the developing devices 7M, 7C, 7Y, and 7B, toner adheres to the electrostatic latent images formed on the surfaces of the photosensitive drums 4M, 4C, 4Y, and 4B, and a toner image is formed. Above the developing devices 7M, 7C, 7Y, and 7B, toner hoppers 8M, 8C, 8Y, and 8B that store toners of magenta, cyan, yellow, and black are disposed, and the developing devices 7M, 7C, 7Y, Each color toner is supplied to 7B as needed.

  When the photosensitive drums 4M, 4C, 4Y, and 4B further rotate, the toner image formed on the surface of the photosensitive drum comes to a position facing the transfer belt 31. In synchronization with this timing, the registration roller 21 rotates and the transfer belt 31 rotates so that the paper reaches the image forming units 2M, 2C, 2Y, and 2B. As the transfer belt 31 transports the paper in the paper transport direction, the magenta, cyan, yellow, and black color toner images pass between the transfer belt 31 and the photosensitive drums 4M, 4C, 4Y, and 4B. The images are successively transferred onto the surface of the passing paper. The sheet on which the toner images of each color are superimposed and transferred passes through a pair of fixing rollers 22 to be fixed. The fixed sheet is guided upward by the conveying roller 23 and discharged to a discharge tray 25 formed on the upper surface of the apparatus by a discharge roller 24. On the other hand, the toner remaining on the surfaces of the photosensitive drums 4M, 4C, 4Y, and 4B after the transfer of the toner image is collected by the cleaning devices 9M, 9C, 9Y, and 9B.

  Here, the transfer belt 31 is disposed on the downstream side in the paper conveyance direction from the photoconductor 4B of the image forming unit 2B and the upstream side in the paper conveyance direction from the photoconductor 4M of the image forming unit 2M. The tension is applied to the driven roller 11 by two tension rollers 131 and 132.

  A driving force of a motor (not shown) is applied to the driving roller 10, and when the driving roller 10 is rotationally driven by this motor, the transfer belt 31 rotates counterclockwise in FIG. It has become. Above the driven roller 11, a charging roller 14 for applying static electricity to the transfer belt 31 is disposed across the transfer belt 31. The sheet on which the toner image from each of the image forming units 2M, 2C, 2Y, and 2B is to be transferred is attached to the surface of the transfer belt 31 that is charged by the charging roller 14, and the transfer belt 31 rotates. It is conveyed along the paper conveyance direction.

  Transfer rollers 15M, 15C, 15Y, and 15B are arranged below the respective photoconductive drums 4M, 4C, 4Y, and 4B with the transfer belt 31 interposed therebetween. A predetermined transfer voltage is applied to each of the transfer rollers 15M, 15C, 15Y, and 15B, and the toner images formed on the surfaces of the photosensitive drums 4M, 4C, 4Y, and 4B face the transfer belt 31. When it reaches the position, it is drawn to the corresponding transfer roller 15M, 15C, 15Y, 15B side and transferred to the paper.

  Each photosensitive drum 4M, 4C, 4Y, 4B and corresponding main chargers 5M, 5C, 5Y, 5B, LED print heads 6M, 6C, 6Y, 6B, developing devices 7M, 7C, 7Y, 7B, toner hopper 8M, The 8C, 8Y, and 8B and the cleaning devices 9M, 9C, 9Y, and 9B are integrated as image forming units 2M, 2C, 2Y, and 2B. Each of the image forming units 2M, 2C, 2Y, and 2B can be pulled out to the front side, and each of the image forming units 2M, 2C, 2Y, and 2B can be pulled out to supply toner to the toner hoppers 8M, 8C, 8Y, and 8B. It is possible to replenish or replace the unit that has been pulled out.

  The transfer belt 31, the transfer rollers 15M, 15C, 15Y, and 15B, and the registration roller 21 are integrated as a transfer belt unit 3, and are attached to be drawable from the right side surface of the apparatus main body 1. Then, the connector 32 (second connecting member) provided at the front end of the transfer belt unit 3 on the apparatus main body side is connected to the connector 26 (first connecting member) provided on the apparatus main body 1, whereby the driving roller 10 or Electricity is supplied to the transfer rollers 15M, 15C, 15Y, 15B and the like.

  For example, when a jam occurs, the transfer belt unit 3 pulls the transfer belt unit 3 outward from the right side surface of the apparatus main body 1 and removes the paper on the transfer belt 31 as shown in FIG. ing. For this reason, as shown in FIG. 6, when the paper conveyance is stopped due to a paper jam (jam) or the like, and the paper is stopped in a state of straddling the connecting portion D, the transfer belt unit 3 is attached and detached. Then, a sheet that hangs down from the transfer belt unit 3 is sandwiched between the connecting portions D, and there is a problem that it becomes impossible to supply electricity to the transfer belt unit 3. Therefore, in the image forming apparatus of the present invention, the cover member 33a and the cover member 27a are provided on the transfer belt unit 3 and the apparatus main body 1 so as to cover the connectors 26 and 32 in plan view, and the hanging paper P is connected. It was made not to be pinched by the part D.

  FIG. 3 is an enlarged plan view of the front end portion of the transfer belt unit, and FIG. 4 is a perspective view thereof. The cover members 33 a and 33 b have a base portion 331 attached to the front end side surface of the transfer belt unit 3 and a comb-like portion 332 extending obliquely downward from the base portion 331. On the other hand, the cover members 27a and 27b include a base portion 271 attached to the apparatus main body 1, a horizontal portion 272 extending horizontally from the lower end of the base portion 271, and comb teeth extending obliquely downward from the end portion of the horizontal portion 272. And 273. The cover members 27a and 27b and the cover members 33a and 33b are attached to the transfer belt unit 3 and the apparatus main body 1 so that the comb-like portions 332 and 273 are engaged with each other. Of course, the cover members 27a and 27b may be formed by extending comb-like portions 273 from the base portion 271 in the same manner as the cover members 33a and 33b.

  With such a configuration, as shown in FIG. 5, when the transfer belt unit 3 is pulled out from the apparatus main body 1, the sheet P is prevented from hanging down on the side surface of the connector 32 by the cover members 33 a and 33 b (FIG. 5). 5 (a)). When the transfer belt unit 3 is inserted into the apparatus main body 1, the comb-like portions 332 (shown in FIG. 4) of the cover members 33a and 33b are comb-like portions 273 (shown in FIG. 4) of the cover members 27a and 27b. To come into mesh. Thereby, the paper P is gradually pushed upward along the inclined surfaces of the cover members 33a and 33b (FIG. 5B). When the transfer belt unit 3 is completely attached to the apparatus main body 1, the free end sides of the cover members 33a and 33b come into contact with the inner wall of the apparatus main body 1, and the free end side bends to near the vertically lower side. The paper P is pushed up above the meshing portions of the comb-like portions 332 and 273 (shown in FIG. 4), and the paper P is reliably prevented from being caught in the connecting portion D between the connector 32 and the connector 26 ( FIG. 5 (c)).

  The material of the cover member is not particularly limited. However, when the transfer belt unit is mounted on the apparatus main body, the cover member needs to fit in a narrow space below the tip of the transfer belt unit. Things are desirable. Such materials include plastics such as polyester.

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 4 is a diagram illustrating a state in which a transfer belt unit is pulled out from the apparatus main body. FIG. 4 is an enlarged plan view of a leading end portion of a transfer belt unit. FIG. 4 is a perspective view of a leading end portion of a transfer belt unit. It is a figure which shows the state by which a sheet | seat is pushed upwards by the comb-tooth shaped part of a cover member engaging. FIG. 4 is a diagram illustrating a state where a sheet is sandwiched between connecting portions by attaching and detaching a transfer belt unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Transfer belt unit D Connection part P Paper 26 Connector (1st connection member)
27a, 27b Cover member (first cover member)
31 Transfer belt 32 Connector (second connecting member)
33a, 33b Cover member (second cover member)
273 Comb-shaped part 332 Comb-shaped part

Claims (3)

A transfer belt unit is attached to the apparatus main body so as to be detachable in the same / reverse direction as the paper conveyance direction by the transfer belt unit. In the image forming apparatus in which the connection member is provided and the second connection member connected to the first connection member is provided in the apparatus main body.
An image forming apparatus, wherein the first cover member and the second cover member are provided on the transfer belt unit and the apparatus main body so as to cover above the first connection member and the second connection member in a front view.   The first cover member and the second cover member each have a comb-like portion inclined downward toward the free end side, and are attached so as to engage with each other when the transfer belt unit is attached to the apparatus main body. Item 2. The image forming apparatus according to Item 1.   The image forming apparatus according to claim 1, wherein at least one of the first cover member and the second cover member has flexibility.

Images