JP2009053290A - Multicolor image forming apparatus - Google Patents

Abstract

An object of the present invention is to provide an inexpensive and highly reliable means for preventing a short circuit due to contact of a photosensitive belt end with a developing device due to warping of the photosensitive belt.
Means for contacting the end of the photosensitive belt and regulating the warpage of the end of the photosensitive member is provided. As a means for regulating the warpage, a rib 30b integrated with the photosensitive belt case 29 is provided between the positions where adjacent developing devices come into contact with the photosensitive belt, and the blade 31 is moved from the rib 30b toward the photosensitive belt. The warp of the photosensitive belt is regulated by extending and suppressing the end of the photosensitive belt by the pressure of the blade 31.
[Selection] Figure 4

Description

  The present invention relates to a multicolor image forming apparatus that can be applied to a color printer, a color copying machine, a color facsimile, and the like, and more particularly, a multicolor that forms a multicolor image by superimposing a plurality of color toner images using an electrophotographic system. The present invention relates to an image forming apparatus.

  A multicolor image forming apparatus that can be applied to a color printer, a color copying machine, a color facsimile, and the like will be described. The multicolor image forming apparatus has a plurality of developing units each containing toner of different colors, and the plurality of developing units are arranged in order so that the toner adheres to the surface of the photoreceptor belt. After the surface of the photosensitive belt is uniformly charged by the contact charger, the photosensitive belt is irradiated with laser light from the exposure device, and an electrostatic latent image corresponding to the image signal is formed. The electrostatic latent image formed on the surface of the photoreceptor is visualized as a toner image by the developing device and transferred to the intermediate transfer member. The toner image transferred to the intermediate transfer member is transferred to a sheet, and the toner image transferred to the sheet is fixed on the sheet by a fixing device, so that a multicolor image is printed.

  There is a photosensitive member driving device in which a cover member that covers and seals the space at both ends in the width direction of the photosensitive belt is provided to prevent toner scattering (see, for example, Patent Document 1).

JP 2002-6682 A

  However, in the conventional configuration, in the photosensitive belt in the photosensitive belt unit, the photosensitive belt has a two-layer structure of a base material and a photosensitive layer, and a liquid photosensitive layer is applied to the base material during manufacturing. When the photosensitive layer is hardened, the photosensitive layer contracts, and the photosensitive belt is warped. Here, when the developing unit makes contact with the photosensitive belt, the end of the photosensitive belt comes into contact with the roller of the developing unit and the metal part of the developing unit due to the warp of the photosensitive belt, so that the photosensitive belt voltage and the developing voltage are increased. Will cause an image defect and an abnormal operation of the image forming apparatus. However, in order to prevent the photoreceptor belt from warping due to the shrinkage of the photosensitive layer during production, many technical problems and enormous costs are required.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a multicolor image forming apparatus capable of preventing a short circuit due to contact of the end portion of the photoconductor belt due to warp of the photoconductor belt to the developing device by an inexpensive and highly reliable means. It is in.

  In order to achieve the above object, a first means of the present invention comprises a photosensitive roller comprising a driving roller, a driven roller, and a photosensitive belt that is suspended from the driving roller and the driven roller and is driven to rotate by the driving roller. A body belt unit, an exposure device that forms an electrostatic latent image based on image information of each color on the photoconductor belt, and toner of different colors are accommodated to perform contact and retraction operations on the photoconductor belt. In a multicolor image forming apparatus having a plurality of developing units that visualize electrostatic latent images with toners of respective colors, means for contacting the end of the photoreceptor belt and regulating the warp of the end of the photoreceptor belt Is provided.

  The second means of the present invention is characterized in that, in the first means, means for restricting the warp of the end portion of the photosensitive belt is provided so as to contact outside the maximum region where the electrostatic latent image is formed. It is what.

  According to a third means of the present invention, in the first means, the means for regulating the warp of the end portion of the photosensitive belt is a rotating roller.

  According to a fourth means of the present invention, in the first means, a plurality of means for regulating the warp of the end portion of the photosensitive belt are provided corresponding to the number of the developing devices. It is.

  A fifth means of the present invention is characterized in that, in the first means, means for regulating the warp of the end portion of the photosensitive belt is integrated and attached to the photosensitive belt case.

  By using the multicolor image forming apparatus of the present invention, it is possible to regulate the end warp of the photoreceptor belt by means that is less expensive and more reliable than the means for preventing the end curvature of the photoreceptor belt by changing the manufacturing method. Contact between the belt end and the developing device can be prevented. Therefore, it is possible to prevent a short-circuit between the photosensitive belt voltage and the developing voltage due to contact between the end portion of the photosensitive belt and the developing device, and it is possible to prevent image defects and abnormal operation of the image forming apparatus and to obtain a high print quality of a multicolor image. It is done.

  In order to prevent a short circuit due to contact of the photosensitive belt end with the developing device due to warping of the photosensitive belt by an inexpensive and highly safe means, the present invention abuts on the photosensitive belt end, Means for regulating the warpage of the part is provided. In the means for regulating the warpage, a rib integrated with the photosensitive belt case is provided between the positions where the adjacent developing devices abut on the photosensitive belt, and the blade is extended from the rib toward the photosensitive belt, Photoconductor belt warpage is regulated by suppressing the end of the photoconductor belt by the pressure of the blade.

  Also, instead of a rib integrated with the photosensitive belt case, a shaft integrated with the photosensitive belt case is provided, and a roller driven with the photosensitive belt is attached to the shaft, and the end of the photosensitive belt is suppressed by the pressure of the roller. Regulates photoconductor belt warpage.

  First, an outline of a full-color printer will be described with reference to FIG.

  The main body of the full-color printer 25 is a developing device 1 to 4 having toners of four colors (black, yellow, cyan, magenta), an exposure device 5, a contact charging brush 8, a photosensitive belt 22, an intermediate transfer member 21, a registration roller 12, and a transfer roller. The roller 13, the static eliminator 15, the fixing device 19, the paper discharge roller 18, and the paper feed cassette 6 are the main components.

  Next, the operation of the full color printer 25 will be described.

  The contact charging brush 8 uniformly charges the surface of the photosensitive belt 22 by a print start signal from a host device (not shown). Subsequently, the exposure device 5 irradiates the surface of the photosensitive belt 22 with the laser beam 7 based on the print data sent from the host device, thereby forming an electrostatic latent image. The toner image is made visible by adhering the toner image to the photosensitive belt 22 by contact with and retracting the photosensitive belt 22. The photosensitive belt 22 is rotated in the P direction by the driving roller 102 to transfer the toner on the photosensitive belt 22 to the intermediate transfer body 21.

  In the case of color printing, the above steps are repeated 3 to 4 times while switching the developing devices 1 to 4. A visible image is formed on the intermediate transfer member 21 with toner of a single color or a plurality of colors, and when a desired transfer is completed or in advance, a stack of paper 27 such as cut paper is fed from the paper feed cassette 6. Each sheet is pulled out by the roller 10 and waits at the registration roller 12.

  At the timing when the position of the visible image formed on the intermediate transfer member 21 coincides with the transfer position on the paper, the paper waiting on the registration roller 12 starts to be conveyed again, and the position of the transfer roller 13 is reached. To transfer the toner image onto the paper. The sheet is peeled off from the intermediate transfer member 21 by the static eliminator 15 and conveyed. At this time, an unfixed toner image is adhered on the sheet, and the unfixed toner image is fixed on the sheet by the fixing device 19 and then discharged to the sheet discharge tray 28 by the sheet discharge roller 18.

  On the surface of the intermediate transfer member 21, toner that has not been transferred to the paper during transfer remains. The toner remaining on the surface of the intermediate transfer member 21 is removed by the cleaner a20. In addition, toner may remain on the surface of the photosensitive belt 22 without being transferred to the intermediate transfer body 21. The toner remaining on the surface of the photosensitive belt 22 is removed by the cleaner b23.

  2 and 3 are schematic views of the photosensitive belt unit 101 related to the embodiment of the present invention.

  FIG. 2 is a perspective view of the photoreceptor belt unit 101 in which three end regulating means 33 are installed at both ends. The photosensitive belt 22 is conveyed in the P direction. The photoreceptor belt case 29 is outside the photoreceptor belt 22 and forms the outer wall of the photoreceptor belt unit 101. The end restricting means 33 is attached integrally with the photosensitive belt case 29, and the end restricting means 33 pushes the end of the photosensitive belt 22 outside the electrostatic latent image forming area, thereby making it possible to perform the present invention. The warping of the end portion of the photosensitive belt 22, which is a problem to be solved, is regulated. Details of the end regulating means 33 will be described later.

  FIG. 3 is a cross-sectional view of the vicinity of the photosensitive belt unit 101. A photosensitive belt unit 101 is disposed so as to face the developing units 1 to 4. The photosensitive belt 22 is suspended by a driving roller 102 rotated by a driving source (not shown), a driven roller 109, a tension roller 103 that applies tension to the photosensitive belt 22, and two idler rollers 108. The tension roller 103 is applied with a tension by a tension spring 106 suspended on an arm 107 supported around an arm rotation fulcrum 105.

  The problem to be solved by the present invention is that the end of the photosensitive belt 22 warps in the direction of the developing units 1 to 4, and the end of the photosensitive belt 22 is in contact with the developing units 1 to 4 during the contact operation of the developing units 1 to 4. It is to prevent a short circuit between the photosensitive belt voltage and the developing voltage from coming into contact with the metal developing roller. Accordingly, by causing a plurality of end restricting means 33 to abut on the photosensitive belt 22 corresponding to the number of developing units, the warping of the end of the photosensitive belt 22 is restricted, and the end of the photosensitive belt 22 and the developing unit. Prevent contact 1-4.

  Next, the end regulating means 33 in the present invention will be described in detail with reference to FIGS.

  FIG. 4 is an enlarged view of the end regulating means 33 in FIG. The rib 30b is installed by integrally molding with the photosensitive belt case 29. The regulating blade 31 is made of a fluororesin having a good sliding property such as PTFE or PFA, and is attached to the photosensitive belt 22 in the conveyance direction P side on the side surface of the rib 30b with a double-sided tape. The regulating blade 31 is brought into contact with the end portion of the photosensitive belt 22 outside the electrostatic latent image forming region, and pressure due to the deflection of the regulating blade 31 is applied, thereby suppressing the warping of the end portion of the photosensitive belt 22.

  As a feature of the present embodiment, since the rib 30b is integrated with the photosensitive belt case 29, the regulating blade 31 can stably contact the photosensitive belt 22 and apply pressure. Further, by using a fluororesin having a good slidability as the material of the end regulating blade 31, frictional wear between the end regulating blade 31 and the photosensitive belt 22 can be reduced. Further, the same effect can be obtained by applying fluorine coating or the like on the contact portion of the end portion regulating blade 31 with the photosensitive belt 22.

Next, another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 5 is a perspective view of the photosensitive belt unit 101 in which the end regulating means 33 in FIG. 2 is changed to another means. FIG. 6 is an enlarged view of the end regulating means 33 in FIG. The end regulating rib 30a is installed by integrally molding with the photosensitive belt case 29, and the length of the end regulating rib 30a extends beyond the electrostatic latent image forming area of the photosensitive belt 22. Here, the warpage of the end portion of the photosensitive belt 22 is restricted by contacting the end portion regulating rib 30a. As a feature of the present embodiment, the end portion regulating rib 30a is integrally formed with the photoreceptor belt case 29, so that the warpage of the end portion of the photoreceptor belt 22 can be regulated without increasing the number of parts. Further, frictional wear can be reduced by adding a fluorine coat or a sheet to the contact surface of the end portion regulating rib 30a to the photosensitive belt 22.

Further, another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 7 is a perspective view of the photoreceptor belt unit 101 in which the end regulating means 33 in FIG. 2 is changed to another means. FIG. 8 is an enlarged view of the end regulating means 33 in FIG. The shaft 30c is installed in the photosensitive belt case 29. The end restricting means 33 has an end restricting roller 32 and a shaft 30c. The end regulating roller 32 is installed on the shaft 30c. Here, the warpage of the end portion of the photosensitive belt 22 is regulated by bringing the end regulating roller 32 into contact with the outside of the electrostatic latent image forming area of the photosensitive belt 22. As a feature of the present embodiment, the end portion regulating roller 32 is driven by the photoreceptor belt 22 and the warpage of the end portion of the photoreceptor belt 22 can be regulated with almost no frictional wear.

  As described above, according to the present invention, the warpage of the end portion of the photosensitive belt 22 is regulated without increasing the cost with a small number of parts, and the end portion of the photosensitive belt 22 is a roller and a developing device of the developing units 1 to 4. By preventing the short circuit between the photoreceptor belt voltage and the developing voltage by contacting the metal parts 1 to 4, it is possible to prevent image defects and abnormal operation of the printer, and to obtain high print quality of multicolor images. it can.

1 is a diagram illustrating an outline of a multicolor image forming apparatus according to an embodiment of the present invention. 1 is a perspective view of a photoreceptor belt unit according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the vicinity of a photoreceptor belt of a multicolor image forming apparatus in which the photoreceptor belt unit is installed. 2 is a partially enlarged perspective view of the photosensitive belt unit. FIG. FIG. 6 is a perspective view of a photoreceptor belt unit according to another embodiment of the present invention. 2 is a partially enlarged perspective view of the photosensitive belt unit. FIG. FIG. 6 is a perspective view of a photoreceptor belt unit according to still another embodiment of the present invention. 2 is a partially enlarged perspective view of the photosensitive belt unit. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1-4 ... Developer, 5 ... Exposure device, 6 ... Feed cassette, 7 ... Laser beam, 8 ... Contact charger, 10 ... Feed roller, 12 ... Registration roller, 13 ... Transfer roller, 15 ... Staticator, DESCRIPTION OF SYMBOLS 18 ... Paper discharge roller, 19 ... Fixing device, 20 ... Cleaner a, 21 ... Intermediate transfer body, 22 ... Photoconductor belt, 23 ... Cleaner b, 25 ... Full color printer, 27 ... Paper, 28 ... Paper discharge tray, 29 ... Photoconductor belt case, 30a ... end regulating rib, 30b ... rib, 30c ... shaft, 31 ... end regulating blade, 32 ... end regulating roller, 33 ... end regulating means, 101 ... photoconductor belt unit, 102 ... Drive roller, 103 ... tension roller, 105 ... arm rotation fulcrum, 106 ... tension spring, 107 ... arm, 108 ... idler roller, 109 ... driven roller.

Claims (5)

  A photosensitive belt unit including a driving roller, a driven roller, a photosensitive belt suspended from the driving roller and driven by the driven roller, and image information of each color on the photosensitive belt; And an exposure device that forms an electrostatic latent image based on the image forming apparatus, and a plurality of toners that store toners of different colors and make the electrostatic latent image visible with each color toner by performing contact and retraction operations on the photosensitive belt. A multicolor image forming apparatus having a developing unit, comprising means for abutting against an end portion of the photosensitive belt and regulating warpage of the end portion of the photosensitive belt.   2. The multicolor image forming apparatus according to claim 1, wherein means for regulating the warp of the end portion of the photosensitive belt is provided so as to come into contact with the outside of the maximum area where the electrostatic latent image is formed.   2. The multicolor image forming apparatus according to claim 1, wherein the means for regulating the warp of the end portion of the photosensitive belt is a rotating roller.   2. The multicolor image forming apparatus according to claim 1, wherein a plurality of means for regulating the warp of the end portion of the photosensitive belt are provided corresponding to the number of the developing devices.   2. The multicolor image forming apparatus according to claim 1, wherein the means for regulating the warp of the end portion of the photosensitive belt is integrally attached to the photosensitive belt case.

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