JP2015121715A - Charger and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger and an image forming apparatus, in which a suspended toner can be prevented from adhering to a charger that charges a photoreceptor.SOLUTION: An image forming apparatus 100 includes a photoreceptor drum 11 and a charger 12, and carries out an image forming process on a sheet by an electrophotographic system. The charger 12 is disposed in such a manner that a longitudinal direction of a chassis 121 is aligned to an axial direction of the photoreceptor drum 11 and that an open face 122 of the chassis 121 opposes to a surface of the photoreceptor drum 11. A mesh-like grid electrode 123 is arranged on the open face 122 of the chassis 121. The charger 12 is provided with a sealing material 20 at each end, in the longitudinal direction of the chassis 121, of the grid electrode 123. The sealing material 20 seals a gap between the grid electrode 123 and the photoreceptor drum 11.

Description

  The present invention relates to a charger and an image forming apparatus for charging a photoreceptor in an electrophotographic image forming process.

  In an electrophotographic image forming apparatus, an electrostatic latent image is formed on the surface of a photosensitive member by an exposure unit after the surface of the photosensitive member is charged by a charger, and toner is supplied by a developing unit to supply the electrostatic latent image. Is visualized as a toner image, and the toner image is directly or indirectly transferred from the surface of the photoreceptor to the paper. The toner remaining on the surface of the photoconductor after the transfer of the toner image causes image formation failure at the time of the next transfer, and is removed by, for example, a cleaning blade.

  The photosensitive member is less charged by the charger at both ends than at the center of the surface. For this reason, the toner supplied by the developing device may float inside the apparatus from both ends of the surface of the photoreceptor. The cleaning blade makes the tip contact with the surface of the photoconductor to remove the remaining toner from the surface of the photoconductor. For this reason, the toner leaking from both ends of the cleaning blade may float inside the apparatus. When these floating toners adhere to the charger, they may cause charging failure by the charger and may cause image formation failure.

  In order to prevent the floating toner from adhering to the charger, the charger for charging the toner image on the surface of the intermediate transfer member has a toner collecting electrode for collecting the toner floating from the surface of the intermediate transfer member. Some are provided (for example, see Patent Document 1). It can be considered that this charger is adapted as a charger for charging the photosensitive member.

JP 2007-171348 A

  However, in addition to the charging device, an exposure device, a developing device, and a cleaning blade are disposed around the photoreceptor. For this reason, if the above-described toner collecting electrode is left energized after the surface of the photosensitive member is charged, the electrostatic latent image and the toner image may be disturbed. Further, if the energization of the toner collecting electrode described above is stopped after charging the surface of the photoconductor, the floating toner may not be collected and may adhere to the charger. As described above, the toner collecting electrode cannot be used for the charger for charging the photosensitive member.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a charger that charges a photosensitive member without using a toner collecting electrode, and that can prevent floating toner from adhering, and an image forming apparatus.

  The charger according to the present invention includes a sealing material and is used in an electrophotographic image forming apparatus. The charger is configured such that the longitudinal direction of the casing coincides with the axial direction of the photoreceptor, and the open surface of the casing is the surface of the photoreceptor. The surface of the photosensitive member is charged. The sealing material is provided at at least one end on the open surface side of the housing in the longitudinal direction, and closes the space between the photoconductor and the housing.

  During the image forming process, the surface of the photoconductor is charged by a charger. Since both ends of the surface of the photoreceptor are less charged than the central portion, when toner is supplied from the developing device, the toner may float from both ends. In the charger, since at least one end portion on the open surface side of the housing and the surface of the photosensitive member are blocked by the sealing material, toner enters from at least one end portion on the open surface side of the housing. Can be prevented.

  Further, in the configuration further including the grid electrode provided on the entire open surface of the housing, it is preferable that the sealing material closes the space between the photoreceptor and the grid electrode.

  Since the grid electrode is sealed with a sealant between the photoconductor and the floating toner, it is possible to prevent the floating toner from adhering. Since the charger can prevent the toner from adhering to the grid electrode, it can prevent charging failure.

  In the configuration further including a cleaning blade that abuts the front end portion on the surface of the photoconductor to clean the surface of the photoconductor, the seal material is outside the image forming area of the photoconductor in the axial direction and of the cleaning blade. It is preferably located inside the end.

  In the charger, since the sealing material is provided inside the end portion of the cleaning blade, the toner leaking from the end portion of the cleaning blade can be prevented from entering and adhering to the inside. Further, since the sealing material is provided outside the image forming area of the photoconductor, even if it comes into contact with the surface of the photoconductor, the image forming area of the photoconductor is not damaged and image formation failure does not occur.

  Further, in a configuration further comprising a cleaning blade that abuts the tip of the surface of the photoconductor to clean the surface of the photoconductor, the sealing material is a moquette material, and the flow of hair moves in the direction of movement of the surface of the photoconductor It is preferable that the end of the cleaning blade is positioned outside the image forming area of the photoconductor and between both ends in the axial direction.

  Since the toner leaking from the end of the cleaning blade moves along the flow of the hair of the sealing material, the charger can prevent the toner leaking from the end of the cleaning blade from entering and adhering to the inside. Further, since the sealing material is provided outside the image forming area of the photoconductor, even if it comes into contact with the surface of the photoconductor, the image forming area of the photoconductor is not damaged and image formation failure does not occur.

  The image forming apparatus of the present invention includes a photoreceptor, the above-described charger, and a transfer device. A toner image is formed on the surface of the photoreceptor. The charger charges the surface of the photoreceptor before a toner image is formed on the surface of the photoreceptor. The transfer device transfers the toner image directly or indirectly from the surface of the photoreceptor to the paper.

  Since the image forming apparatus can prevent the floating toner from adhering to the charger, the surface of the photoconductor can be uniformly charged by the charger and a good image can be formed.

  According to the present invention, it is possible to prevent the floating toner from adhering to the charger for charging the photosensitive member.

It is the schematic diagram which looked at the circumference of the charger concerning a 1st embodiment of this invention from the front. It is the schematic diagram which looked at the circumference of the charger from the upper surface. It is the schematic diagram which looked at the periphery of the charger which concerns on 2nd Embodiment from the upper surface.

  An image forming apparatus including a charger according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the image forming apparatus 100 includes, for example, a photosensitive drum 11, a charger 12, a developing device 13, and a cleaning blade 14, and uses image data input from an external device (not shown). An image forming process is performed on the paper by an electrophotographic method.

  Around the photosensitive drum 11, a charger 12 that charges the surface of the photosensitive drum 11 by corona discharge, a developing device 13 that visualizes an electrostatic latent image formed on the surface of the photosensitive drum 11 into a toner image, and A cleaning blade 14 for cleaning the surface of the photosensitive drum 11 is disposed.

  The photosensitive drum 11 is arranged with its axial direction aligned with the direction from the front side to the back side of the apparatus main body (not shown). The apparatus main body is provided with a fan (not shown) for taking in air outside the apparatus on the front side, and an exhaust port (not shown) for discharging the air inside the apparatus on the back side. Since air flows from the front side to the back side inside the apparatus main body, ozone generated by corona discharge of the charger 12 is discharged to the outside from the back side of the apparatus main body.

  The charger 12 aligns the longitudinal direction of the casing 121 with the axial direction of the photosensitive drum 11 and arranges the open surface 122 of the casing 121 to face the surface of the photosensitive drum 11. A discharge electrode 124 is stretched along the longitudinal direction of the casing 121 at the center of the casing 121. The discharge electrode 124 is a corona wire or a sawtooth electrode, and performs a corona discharge from the tip when a voltage is applied. The discharge area of the discharge electrode 124 coincides with the area including the image forming area (area where the toner image is formed) on the surface of the photosensitive drum 11 in the axial direction of the photosensitive drum 11.

  A mesh-like grid electrode 123 is disposed on the open surface 122 of the housing 121. The grid electrode 123 is provided with an opening along a central portion facing the discharge electrode 124. This opening allows the inside of the housing 121 to communicate with the space on the photosensitive drum 11 side.

  A cleaning blade 14 is disposed in the vicinity of the upstream side of the charger 12 in the moving direction of the surface of the photosensitive drum 11. The cleaning blade 14 removes the toner from the surface of the photosensitive drum 11 by bringing the tip portion 141 into contact with the surface of the photosensitive drum 11 in an obliquely upward direction of the charger 12.

  Further, the tip 141 of the cleaning blade 14 contacts the surface of the photosensitive drum 11 in a wider area than the image forming area on the surface of the photosensitive drum 11.

  A developing unit 13 is disposed in the vicinity of the downstream side of the charger 12 in the moving direction of the surface of the photosensitive drum 11. The developing unit 13 includes a storage unit 131 that stores toner, and supplies the toner to the electrostatic latent image formed on the surface of the photosensitive drum 11 to visualize the toner image.

  As shown in FIG. 2, seal materials 15 are provided at both ends of the cleaning blade 14 in the axial direction of the photosensitive drum 11. Each sealing material 15 is disposed outside the image forming area on the surface of the photosensitive drum 11 in the axial direction of the photosensitive drum 11 and so that the end of the cleaning blade 14 is positioned between both ends. Is done. Each sealing material 15 blocks between the end of the cleaning blade 14 and the surface of the photosensitive drum 11. By being arranged in this way, the sealing material 15 prevents the toner leaking from both ends of the cleaning blade 14 during cleaning from floating inside the apparatus.

  Further, the charger 12 is provided with the sealing material 20 at each of both end portions of the grid electrode 123 in the longitudinal direction of the casing 121. Each sealing material 20 is a moquette material, and in the axial direction of the photosensitive drum 11, outside the image forming area on the surface of the photosensitive drum 11 and inside the end of the cleaning blade 14 in the longitudinal direction of the housing 121. Is provided. Further, as shown in FIG. 1, the sealing material 20 closes the space between the grid electrode 123 and the photosensitive drum 11.

  As described above, the charger 12 prevents the toner floating from both ends of the surface of the photosensitive drum 11 from entering the inside by the sealing material 20 and prevents the toner from adhering to the grid electrode 123. The charger 12 prevents the toner leaking from both ends of the cleaning blade 14 from floating by the sealing material 15, but it may leak slightly. The leaked toner is also prevented from entering the inside by the sealing material 20 and is prevented from adhering to the grid electrode 123. As a result, the image forming apparatus 100 can prevent poor charging of the photosensitive drum 11 by the charger 12 and can perform good image formation.

  Further, since the sealing materials 15 and 20 are provided outside the image forming area of the photosensitive drum 11, even if they contact the surface of the photosensitive drum 11, the image forming area of the photosensitive drum 11 is not damaged. Does not cause image formation failure.

  In the above-described embodiment, the charger including the grid electrode 123 is described as an example. However, the present invention can also be applied to a charger that does not include the grid electrode 123.

  An image forming apparatus including a charger according to a second embodiment of the present invention will be described with reference to the drawings. The charging device 12A is different from the sealing material 20 included in the charging device 12 according to the first embodiment in the shape of the sealing material 20A provided in the housing 121. Only the differences will be described below.

  As shown in FIG. 3, the sealing material 20 </ b> A is a moquette material, and the flow of hair coincides with the moving direction of the surface of the photosensitive drum 11. The sealing material 20A is provided outside the image forming area on the surface of the photoconductive drum 11 in the axial direction of the photoconductive drum 11 and so that the end of the cleaning blade 14 is located between both ends. ing. Further, the sealing material 20 </ b> A closes between the grid electrode 123 and the photosensitive drum 11.

  As described above, the charger 12A prevents the toner floating from both ends of the surface of the photoconductive drum 11 from moving into the sealing material 20A along the moving direction of the surface of the photoconductive drum 11, thereby preventing the toner from entering the inside. , To prevent adhesion to the grid electrode 123. The charger 12 prevents the toner leaking from both ends of the cleaning blade 14 from floating by the sealing material 15, but it may leak slightly. The leaked toner is also moved along the moving direction of the surface of the photosensitive drum 11, so that the leaked toner is prevented from entering the inside and is prevented from adhering to the grid electrode 123. As a result, the image forming apparatus 100 can prevent poor charging of the photosensitive drum 11 by the charger 12A, and can perform good image formation.

  Further, since the sealing material 20A is provided outside the image forming area of the photoconductive drum 11, even if it contacts the surface of the photoconductive drum 11, the image forming area of the photoconductive drum 11 is not damaged and image formation is performed. Does not cause defects.

  An image forming apparatus including a charger according to a third embodiment of the present invention will be described with reference to the drawings. The charger 12B is different from the charger 12 according to the first embodiment in that a sealing material 20 is provided at one end of the grid electrode 123 in the longitudinal direction of the housing 121. Only the differences will be described below.

  The charger 12 </ b> B is provided with a sealing material 20 at the end of the grid electrode 123 in the longitudinal direction of the housing 121 on the back side of the apparatus main body. The sealing material 20 is provided outside the image forming area on the surface of the photosensitive drum 11 and inside the cleaning blade 14 in the longitudinal direction of the housing 121 in the axial direction of the photosensitive drum 11.

  In the charger 12B, the sealing material 20 is provided in the housing 121, but the sealing material 20A may be provided at the end of the grid electrode 123 on the back side of the apparatus main body.

  As described above, since the air inside the apparatus flows from the front side to the back side, the floating toner moves to the back side inside the apparatus. The charger 12 </ b> B is provided with the sealing material 20 at the end on the back side, thereby efficiently preventing the floating toner from entering the inside and preventing the toner from adhering to the grid electrode 123. As a result, the image forming apparatus 100 can prevent the charging failure of the photosensitive drum 11 by the charger 12B, and can perform good image formation.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

12, 12A, 12B ... charger 20, 20A ... sealing material 121 ... casing 122 ... open surface

Claims (5)

Used in an electrophotographic image forming apparatus, the longitudinal direction of the housing is made to coincide with the axial direction of the photoconductor, and the open surface of the housing is arranged to face the surface of the photoconductor, and the surface of the photoconductor A charger for charging
A charger provided with a sealing material provided at at least one end on the open surface side of the housing in the longitudinal direction, which seals between the photoconductor and the housing. Further comprising a grid electrode provided on the entire open surface of the housing,
The charger according to claim 1, wherein the sealing material closes a space between the photoconductor and the grid electrode. A cleaning blade for cleaning the surface of the photosensitive member by bringing a tip portion into contact with the surface of the photosensitive member;
3. The charger according to claim 1, wherein the sealing material is located outside an image forming region of the photoconductor and inside an end portion of the cleaning blade in the axial direction. A cleaning blade for cleaning the surface of the photosensitive member by bringing a tip portion into contact with the surface of the photosensitive member;
The sealing material is a moquette material,
The flow of the hair of the sealing material matches the moving direction of the surface of the photoreceptor,
3. The charger according to claim 1, wherein an end portion of the cleaning blade is positioned outside the image forming area of the photoconductor and between both ends in the axial direction. A photoreceptor on which a toner image is formed;
The charger according to any one of claims 1 to 4, wherein the charger charges the surface of the photoconductor before the toner image is formed on the surface of the photoconductor.
An image forming apparatus comprising: a transfer unit that transfers a toner image directly or indirectly from the surface of the photosensitive member to a sheet.

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