JP2013097373A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which is light in weight and has high operability.SOLUTION: There is provided an image forming apparatus, which comprises: an elastic member for bringing a secondary transfer roller into contact with an intermediate transfer belt by pressing a secondary transfer unit with a pressing force to rotate; a transfer belt unit positioning part having a locking part to a transfer belt unit; a secondary transfer roller positioning part in which the secondary transfer roller is fitted; a second pressing link for holding or releasing the secondary transfer roller; a first pressing link for transmitting the pressing force of the second pressing link to a pressing force releasing member provided in a supporting frame; and a secondary transfer roller holding member for holding the elastic member, the transfer belt unit positioning part, the secondary transfer roller positioning part, the second pressing link and the first pressing link.

Description

  Embodiments described herein relate generally to an image forming apparatus applied as an electrophotographic apparatus that forms a color image, for example.

  Some conventional electrophotographic apparatuses employ a transfer roller system as a system for transferring an image onto paper. In this system, it is necessary to press the transfer roller against an image carrier such as an endless intermediate transfer belt, and there is a system provided with a mechanism for applying pressure with an elastic member from behind the transfer roller.

  In such an electrophotographic apparatus, in order to remove the jammed paper, it is necessary to have a structure in which the secondary transfer roller includes an opening portion that is opened from the main body side. However, in such an electrophotographic apparatus, it is necessary to apply a force against the pressing of the transfer roller by the elastic member when closing the opening portion, which is a factor that hinders operability. In addition, in order to increase the strength of the open portion that receives the pressing force of the transfer roller, it is necessary to employ a strong structure and parts.

JP 2009-288376 A

  An object of the present invention is to provide an image forming apparatus that is lightweight and has high operability.

  In order to solve the above problems, an image forming apparatus according to an embodiment includes an image carrier that is held in a housing, an image forming unit that forms an electrostatic latent image on the image carrier, and the image forming unit. A developing unit that develops the formed electrostatic latent image into a developer image, a transfer belt unit that includes an intermediate transfer belt to which the developer image developed by the developing unit is transferred, and a transfer to the intermediate transfer belt A secondary transfer roller for transferring the developed developer image to a recording medium, a secondary transfer unit supported rotatably about a fulcrum, and mounting the secondary transfer roller on the rotating end side; and the secondary transfer roller An elastic member for rotating the transfer unit by pressing with a pressing force so that the secondary transfer roller comes into contact with the intermediate transfer belt; and a transfer belt unit positioning unit provided with a locking part for the transfer belt unit; The above A secondary transfer roller positioning portion with which the secondary transfer roller is fitted, a second pressing link for holding or releasing the secondary transfer roller, and a pressure release provided on the support frame for pressing the second pressing link A first pressing link that transmits to the member; and a secondary transfer roller holding member that holds the elastic member, the transfer belt unit positioning unit, the secondary transfer roller positioning unit, the second pressing link, and the first pressing link. It is characterized by.

1 is an external perspective view showing an electrophotographic apparatus as an image forming apparatus according to an embodiment. 1 is an external perspective view showing a state in which a double-sided printing unit of an electrophotographic apparatus of an embodiment is opened. FIG. 3 is an explanatory diagram illustrating an internal configuration of the electrophotographic apparatus according to the embodiment. FIG. 3 is an enlarged perspective view showing a jam processing opening portion and its vicinity in the electrophotographic apparatus of the present embodiment. Explanatory drawing which shows the jam processing open | release part and its periphery of the electrophotographic apparatus of this embodiment. Explanatory drawing which shows the 1st press link of the electrophotographic apparatus of this embodiment. 2A and 2B are diagrams for explaining the rotation of the press release cam of the electrophotographic apparatus of the present embodiment, in which FIG. 1A is a diagram illustrating a state in which the press release cam is in a normal position, and FIG. It is a figure showing the state which the press release cam rotated in the direction to do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external perspective view showing an electrophotographic apparatus as an image forming apparatus of the present embodiment.

  A document transport unit 22 that transports a document to a document table is provided on the upper surface of the electrophotographic apparatus 1. An operation panel 23 is provided on the upper front side of the electrophotographic apparatus 1, and a plurality of paper cassettes 24 are arranged on the lower side. On one side surface of the electrophotographic apparatus 1, a double-sided printing unit 25 used for printing an image on both sides of a sheet is provided so as to be openable and closable.

  FIG. 2 is an external perspective view showing a state where the duplex printing unit 25 is opened.

  By opening the double-sided printing unit 25, an opening / closing cover 26 as a support frame for mounting a secondary transfer unit described later is exposed to the outside.

  FIG. 3 is an explanatory diagram showing the internal configuration of the electrophotographic apparatus 1.

  In the electrophotographic apparatus 1, a photosensitive drum 2 as an image carrier is rotatably provided. A developing unit that develops an electrostatic latent image formed by a charger 5 that charges the surface of the photosensitive drum 2 at a predetermined potential around the photosensitive drum 2 and an exposure device that will be described later along the rotation direction. Developing device 8B for supplying monochrome black toner, rotary developing device 8A for supplying color toner, and an intermediate transfer member for temporarily transferring a developer image (toner image) developed by these toners. The intermediate transfer belt 3 and a cleaner 6 for removing residual toner on the photosensitive drum 2 are disposed.

  The color rotary developing device 8A includes a first developing unit 8a that supplies yellow toner, a second developing unit 8b that supplies cyan toner, and a third developing unit 8c that supplies magenta toner.

  The intermediate transfer belt 3 is stretched between the first to fourth rollers 3 a to 3 d with a predetermined tension to constitute a transfer belt unit 35, and is pressed against the photosensitive drum 2 by the primary transfer roller 12. . A cleaner 15 a that cleans the intermediate transfer belt 3 is in contact with a portion of the intermediate transfer belt 3 that is wound around the first roller 3 a.

  Below the developing devices 8A and 8B, the above-described exposure device 4 is provided as image forming means for forming an electrostatic latent image on the photosensitive drum 2.

  Below the exposure device 4, the above-described paper feed cassette 24 for storing paper as a recording medium is provided. The paper feed cassette 24 is provided with a pickup roller 7 for taking out paper. The paper taken out by the pickup roller 7 is separated and sent out one by one by the paper feed roller 15 and the separation roller 16, and is conveyed along the conveyance system 19.

  In the conveyance system 19, a conveyance roller pair 9, a registration roller pair 17, and a secondary transfer roller 11 as a transfer roller are sequentially arranged along the sheet conveyance direction. The registration roller pair 17 temporarily stops the conveyed sheet, corrects the inclination of the sheet with respect to the conveying direction, and makes the leading end of the sheet coincide with the leading end of the toner image on the intermediate transfer belt 3. The secondary transfer roller 11 is in pressure contact with the roller 3 c via the intermediate transfer belt 3.

  A fixing device 13 for fixing the toner image transferred to the paper to the paper is disposed downstream of the secondary transfer roller 11 in the paper conveyance direction. The fixing device 13 includes a heating roller 13a and a pressure roller 13b that is in pressure contact with the heating roller.

  A discharge roller pair 30 for discharging the paper is provided on the downstream side of the fixing device 13 in the paper conveyance direction. On the carry-out side of the discharge roller pair 30, a discharge tray 31 that receives discharged paper is provided.

  Next, the printing operation of the above-described electrophotographic apparatus will be described.

  First, a document is set on the document transport unit 22 and the copy button on the operation panel 23 is turned on. As a result, the document is conveyed to the document table and is optically read by a known reading device (not shown) to generate read information. At this time, the surface of the photosensitive drum 2 is uniformly charged by the charger 5. The charged photosensitive drum 2 is irradiated with information light corresponding to the read information by the exposure device 4 to form an electrostatic latent image.

  The electrostatic latent image is sent to the developing device 8B or the developing device 8A by the rotation of the photosensitive drum 2, and black toner is supplied from the developing device 8B, or cyan, magenta, and yellow toners are supplied from the developing device 8A. And developed. Specifically, in the case of a color image, an electrostatic latent image corresponding to each color is sequentially formed on the photosensitive drum, and the corresponding toner of the developing device 8A that rotates at a predetermined angle corresponding to the electrostatic latent image of each color. Thus, the electrostatic latent images on the photosensitive drum 2 are sequentially developed. The developed toner image is sent onto the intermediate transfer belt 3 by the rotation of the photosensitive drum 2 and is primarily transferred by the primary transfer roller 12. After this transfer, the photosensitive drum 2 is subjected to light neutralization by a static eliminator (not shown), and the toner remaining on the photosensitive drum 2 is cleaned by a cleaner 6.

  On the other hand, at this time, a sheet is supplied and sent between the intermediate transfer belt 3 (roller 3c) and the secondary transfer roller 11. The toner image on the intermediate transfer belt 3 is secondarily transferred to this sheet. After the transfer, the sheet is peeled off from the intermediate transfer belt 3 and sent to the fixing device 13 where the toner image is heated and pressurized and fixed. After this fixing, the paper is discharged to the outside via the discharge roller pair 30 and placed on the discharge tray 31.

  The secondary transfer unit 36 (see FIG. 4) that holds the secondary transfer roller 11 is disposed in a mechanism that is opened when processing jammed paper, and presses the secondary transfer roller against the intermediate transfer belt 3. The mechanism section is fixed to the casing section on the main body side. Both ends of the opening / closing cover 26 are rotatably supported by the electrophotographic apparatus 1 via a support shaft (not shown).

  When the paper is jammed between the secondary transfer unit 36 and the transfer belt unit 35, the paper can be removed by opening the open / close cover 26 to separate the secondary transfer unit 36 from the transfer belt unit 35. A portion that is released when a paper jam occurs is referred to as a jam processing release portion 27.

  The jam processing release unit 27 will be described with reference to FIGS.

  FIG. 4 is an external perspective view showing the jam processing opening portion 27 and its surroundings, and shows a state in which the opening / closing cover 26 is opened. The secondary transfer unit 36 is held by the jam processing release unit 27 with a degree of freedom via a holding member 56 attached to the electrophotographic apparatus 1. The secondary transfer roller 11 is rotatably attached to the secondary transfer unit 36.

  FIG. 5 is an explanatory diagram showing the secondary transfer roller holding member 51 and its peripheral portion.

  The secondary transfer roller holding member 51 includes a transfer belt unit positioning unit 52, a secondary transfer roller positioning unit 53, and a pressing mechanism 54.

  The transfer belt unit positioning unit 52 guides the transfer belt unit 35 to be disposed at an appropriate position with respect to the electrophotographic apparatus 1. The secondary transfer roller positioning unit 53 guides the secondary transfer unit 36 so as to be disposed at a position facing the intermediate transfer belt 3.

  The secondary transfer unit 36 shown in FIG. 4 is held by the jam release unit 27 with a degree of freedom. When the jam processing release portion 27 is closed, the secondary transfer unit 36 is guided by the secondary transfer roller positioning portion 53 and guided to a position facing the intermediate transfer belt 3. When the secondary transfer unit 36 is inserted into the positioning portion 53, the secondary transfer roller 11 is pressed against the intermediate transfer belt 3 by the pressing mechanism 54 of the secondary transfer roller holding member 51.

  As shown in FIG. 5, the pressing mechanism 54 includes an elastic unit 41 including an elastic member 61 and a pressing force transmitting portion 62, and a first link link 63 and a pressing link rotation fulcrum 71 serving as a rotation fulcrum. A first pressing unit 42, a second pressing unit 43 composed of a second pressing link 64 and a second pressing link rotation fulcrum 65, a pressure releasing link 66 and a pressure releasing cam 81. A unit 45 is provided.

  The elastic unit 41, the second pressing unit 43, and the pressing releasing unit 45 are linked to each other using the first pressing unit 42 as a relay member. The mutual operation will be described using the members constituting each unit.

  The elastic member 61 forming the elastic unit 41 is, for example, a spring. The elastic member 61 presses the secondary transfer roller 11, and the secondary transfer unit is rotated by the pressing force, and the secondary transfer roller 11 is pressed against the intermediate transfer belt 3 (roller 3c).

  The pressing force of the elastic member 61 is transmitted to the first pressing link 63 via the pressing force transmission unit 62. The pressing force transmission part 62 is a cylindrical member having a diameter that covers the elastic member 61, for example. The pressing force transmission part 62 is made of a hard material such as hard plastic that does not deform in shape due to the pressing force of the elastic member 61.

  FIG. 6 is a diagram for explaining the first pressing unit 42. The first pressing link 63 that forms the first pressing unit 42 includes a pressing link rotation fulcrum 71 serving as a fulcrum of rotation, and a first rotating body shaft 72 that rotatably supports the pressing force transmission unit 62. And a second rotating body shaft 73 and a rotating body 74 that transmit a pressing force to the second pressing link 64, and a third rotating body shaft 75 that rotatably supports the pressing release link 66.

  The second pressing unit 43 shown in FIG. 5 is a member that holds the secondary transfer roller 11. One end of the second pressing link 64 forming the second pressing unit 43 is in contact with the second rotating body shaft 73 and the rotating body 74. The other end is provided with a second pressing link rotation fulcrum 65 which is a rotation fulcrum, and the second pressing link 64 rotates as the rotating body 74 rotates.

A press release cam 81 forming the press release unit 45 is attached to the opening / closing cover 26. The press release cam 81 rotates together with the opening / closing cover 26 with the opening / closing portion fulcrum 82 as a fulcrum. The press release cam 81 is rotatably connected to the first press link 63 via the press release link 66.
The press release link 66 forming the press release unit 45 connects the first press link 63 and a press release cam 81 as a press release member so as to be rotatable at both ends. When the first pressing link 63 and the pressing release cam 81 operate with each other, the elastic force of the elastic member 61 is transmitted to the pressing release cam 81 via the first pressing link 63. One of the two ends is rotatably supported on the first pressing link 63 by the third rotating body shaft 75, and the other is provided with the rotating body 76. The rotating body 76 rotates along the side portion of the pressing release cam 81.

  Next, the rotation of the press release cam 81 and the operation of the opening / closing cover 26 associated therewith will be described with reference to FIG. As shown in FIG. 7A, when the press release cam 81 is pressed in the pressurizing direction (arrow A direction) of the first pressing link 63, the opening / closing portion fulcrum 82 rotates in the arrow P direction. Along with this, the press release cam 81 also rotates in the direction of the arrow P and becomes a normal position. When the press release cam 81 is in the proper position, the open / close cover 26 is closed.

When a force is applied from the outside in the direction in which the opening / closing cover 26 is closed, that is, in the direction of the arrow M, the opening / closing portion fulcrum 82 and the press release cam 81 rotate in the direction of the arrow Q. A force is applied to the pressing release link 66 in the direction of arrow A. At this time, a force in the direction opposite to the arrow B is also applied to the first pressing link 63, and the pressing link rotation fulcrum 71 rotates in the direction opposite to the arrow P. At this time, force is applied in the direction in which the elastic member 61 is loosened. The second pressing link rotation fulcrum 65 rotates in the direction opposite to the arrow Q, and the secondary transfer roller 11 (see FIG. 3) is held by the second pressing link 64.

As shown in FIG. 7B, when the pressing from the pressing link 63 to the pressing release cam 81 is released (arrow B), the opening / closing portion fulcrum 82 rotates in the arrow Q direction. Accordingly, the press release cam 81 also rotates in the arrow Q direction. At this time, the opening / closing cover 26 rotates in the arrow Q direction with the opening / closing portion fulcrum 82 as a fulcrum.

  Further, when a force is applied from the outside in the direction in which the opening / closing cover 26 is opened, that is, in the direction of the arrow N, the opening / closing portion fulcrum 82 and the press release cam 81 rotate in the direction of the arrow Q. A force is applied to the pressing release link 66 in the direction of arrow B. At this time, the force in the direction of arrow B is also applied to the first pressing link 63, and the pressing link rotation fulcrum 71 rotates in the direction opposite to the arrow Q. At this time, force is applied in the direction in which the elastic member 61 contracts. The second pressing link rotation fulcrum 65 rotates in the same direction as the arrow Q, and the secondary transfer roller 11 (see FIG. 3) held by the second pressing link 64 is released.

  As described above, in the electrophotographic apparatus 1 of the present embodiment, when the opening / closing cover 26 is opened / closed, the pressing release cam 81 operates to control the pressing to the secondary transfer roller 11. As a result, the operability can be improved by opening and closing the opening / closing cover 26 and simultaneously releasing the reaction force of the secondary transfer roller.

  In addition, by setting the reaction force acting on the release of the pressure in the direction of the opening / closing part fulcrum 82, the part that requires strength is limited to the periphery of the fulcrum, and the material thickness of parts other than the corresponding part is reduced, thereby reducing the material cost And a lighter electrophotographic apparatus can be realized.

  Further, by receiving both of the pressure on the secondary transfer roller 11 and the force received by the transfer belt unit 35 with the secondary transfer roller holding member 51, it is possible to limit components that require strength.

  Further, by installing a component that receives stress on the main body side of the apparatus, it is possible to reduce the load on the jam processing opening portion 27, and thus it is possible to reduce the component weight of the opening / closing cover 26.

  In the electrophotographic apparatus 1 used in the above embodiment, the secondary transfer roller holding member 51 is attached to the main body of the electrophotographic apparatus 1, and the press release cam 81 is attached to the opening / closing cover 26. On the contrary, the same effect can be obtained by attaching the secondary transfer roller holding member 51 to the opening / closing cover 26 and attaching the pressing release cam 81 to the main body of the electrophotographic apparatus 1.

  Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 ... Electrophotographic apparatus (housing)
2 ... Photosensitive drum (image carrier)
4. Exposure apparatus (image forming means)
3... Intermediate transfer belts 8A and 8B... Developing device (developing means)
11: Secondary transfer roller 26: Open / close cover (support frame)
35 ... transfer belt unit 36 ... secondary transfer unit 51 ... secondary transfer roller holding member 52 ... transfer belt unit positioning part 53 ... secondary transfer roller positioning part 54 ... pressing mechanism 61 ... elastic member 63 ... first press link 64 ... second press link 66 ... press release link 71 ... first press link rotation fulcrum 81 ... press release cam (Press release member)

Claims (4)

An image carrier held in a housing;
Image forming means for forming an electrostatic latent image on the image carrier;
Developing means for developing the electrostatic latent image formed by the image forming means into a developer image;
A transfer belt unit including an intermediate transfer belt onto which the developer image developed by the developing means is transferred;
A secondary transfer roller for transferring the developer image transferred to the intermediate transfer belt to a recording medium;
A secondary transfer unit which is supported rotatably about a fulcrum and attaches the secondary transfer roller to the rotation end side;
An elastic member that rotates the secondary transfer unit by pressing with a pressing force so that the secondary transfer roller contacts the intermediate transfer belt;
A transfer belt unit positioning portion provided with a locking portion to the transfer belt unit;
A secondary transfer roller positioning portion to which the secondary transfer roller is fitted;
A second pressing link for holding or releasing the secondary transfer roller;
A first pressing link that transmits the pressing of the second pressing link to a pressing release member provided on the support frame;
An image forming apparatus comprising a secondary transfer roller holding member that holds the elastic member, a transfer belt unit positioning unit, a secondary transfer roller positioning unit, a second pressing link, and a first pressing link.   The image forming apparatus according to claim 1, further comprising: a support frame that is rotatably supported by the housing and separates the secondary transfer unit and the transfer belt unit by being opened.   The first pressing link rotates about a first pressing link rotation fulcrum, and the second pressing link and the pressing release are caused by expansion and contraction of an elastic member provided on the secondary transfer roller holding member. The image forming apparatus according to claim 2, wherein the pressing force is transmitted to a member.   The first pressing link includes a pressing release link linked to the pressing release member, and one end of the both ends of the pressing release link rotates around an axis provided in the first pressing link, The image forming apparatus according to claim 3, wherein the other end rotates as a wheel of a shaft provided in the press release link along an outline of the press release member.

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