JP2010091657A - Cleaning device, process unit, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device for stably exhibiting cleaning capability for a long period. <P>SOLUTION: The cleaning device includes a cleaning roller 21 that abuts on a charging roller 3 for charging the surface of an image carrier 2 and removes a foreign substance on the surface of the charging roller 3, and a recovery roller 22 that abuts on the cleaning roller 21 and recovers the foreign substance removed by the cleaning roller 21. The cleaning roller 21 and the recovery roller 22 are constituted of porous rollers forming elastic layers 21b and 22b formed of porous materials on outer peripheries of core materials 21a and 22a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning device that cleans the surface of a charging roller, a process unit including the cleaning device, and an image forming apparatus.

  In an image forming apparatus that employs an electrophotographic system such as a copying machine, a printer, or a facsimile, when performing an image forming operation, the surface of a photosensitive drum as an image carrier is first charged by a charging roller. Next, the charged surface on the photosensitive drum is exposed by a laser beam from the exposure device to form an electrostatic latent image, and toner is supplied from the developing device to the electrostatic latent image to form a toner image. Thereafter, the toner image on the photosensitive drum is transferred onto a transfer sheet as a recording medium, and the transfer sheet passes through a heat fixing device, whereby the toner image is thermally fixed onto the transfer sheet. Further, residual toner remaining on the photosensitive drum after image transfer is removed by a cleaning blade or the like, and the photosensitive drum is charged again.

  In such an image forming apparatus, in order to prevent deterioration due to abrasion of the photosensitive drum and the cleaning blade, a lubricant is applied to the surface of the photosensitive drum so as to extend the life of the parts and improve the cleaning property. Yes.

  However, if an excessive amount of lubricant is applied to the surface of the photosensitive drum, the lubricant adheres to the surface of the charging roller provided in contact with or close to the surface of the photosensitive drum, and the charging roller becomes dirty and causes a charging failure. There is a problem.

  For this purpose, the charging roller is provided with a cleaning roller so as to come into pressure contact with the surface of the charging roller. Even if foreign matters such as lubricant excessively adhering to the surface of the photosensitive drum adhere to the surface of the charging roller, they are removed by the cleaning roller.

  A brush roller is often used as the cleaning roller, but a cleaning roller using a porous roller has been proposed in order to retain more removed foreign matter (see, for example, Patent Document 1).

Further, in order to prevent a reduction in cleaning ability of the brush roller for cleaning the charging roller, there is a fur brush that contacts the brush roller and collects the foreign matter removed by the brush roller (see, for example, Patent Document 2). ).
JP 2008-209488 A JP 2003-66695 A

  However, the invention described in Patent Document 1 can improve the foreign matter holding ability by making the cleaning roller a porous roller, but eventually, when the limit value of the foreign matter holding amount of the porous roller is exceeded, No further foreign matter can be held. If foreign matter that cannot be held by the cleaning roller adheres to the charging roller, charging failure will occur.

  Further, since the invention of Patent Document 2 uses a brush roller as a cleaning roller, the amount of foreign matter is less than that of a porous roller, and it is difficult to stably exhibit a good cleaning ability over a long period of time. Furthermore, since the brush roller has a lower foreign matter holding ability than the porous roller, the foreign matter removed by the brush roller may be scattered around and contaminate the photosensitive drum and other devices.

  In view of such circumstances, the present invention intends to provide a cleaning device capable of stably exhibiting a cleaning capability for a long period of time, a process unit including the cleaning device, and an image forming apparatus. .

  According to the first aspect of the present invention, there is provided a cleaning roller that contacts a charging roller that charges the surface of the image bearing member to remove foreign matter on the surface of the charging roller, and a foreign matter that contacts the cleaning roller and removed by the cleaning roller. In this cleaning device, the cleaning roller and the recovery roller are constituted by a porous roller in which an elastic layer made of a porous material is formed on the outer periphery of the core material.

  In the cleaning device of the present invention, the foreign matter removed by the cleaning roller is further recovered by the recovery roller, so that the cleaning ability of the cleaning roller can be maintained well over a long period of time. In addition, since the cleaning roller and the collection roller are composed of porous rollers, more foreign matters can be collected compared to a brush roller and the like, and the collected foreign matter retention capability is excellent. Thereby, the cleaning device of the present invention can stably exhibit good cleaning performance.

  According to a second aspect of the present invention, in the cleaning device according to the first aspect, the amount of deformation of the elastic layer of the recovery roller at a contact position between the cleaning roller and the recovery roller is determined between the cleaning roller and the recovery roller. This is larger than the deformation amount of the elastic layer of the cleaning roller at the contact position.

  By increasing the deformation amount of the elastic layer of the collecting roller, the foreign matter received from the cleaning roller can be collected inside the elastic layer of the collecting roller. As a result, the collection roller can collect more foreign matter. On the other hand, by reducing the deformation amount of the elastic layer, the cleaning roller can prevent the foreign matter from being pushed into the elastic layer, and can successfully pass the foreign matter to the recovery roller.

  According to a third aspect of the present invention, in the cleaning device according to the first or second aspect, the thickness of the elastic layer of the recovery roller is made larger than the thickness of the elastic layer of the cleaning roller.

  By forming the elastic layer of the recovery roller to be thicker than the elastic layer of the cleaning roller, the deformation amount of the elastic layer of the recovery roller can be determined at the contact position between the cleaning roller and the recovery roller. The amount of deformation can be larger. Thus, as in the second aspect, the collection roller can collect more foreign matter from the cleaning roller.

  According to a fourth aspect of the present invention, in the cleaning device according to any one of the first to third aspects, the density of the porous material constituting the elastic layer of the recovery roller is set to the porosity of the elastic layer of the cleaning roller. It is smaller than the density of the material.

  By making the density of the porous material constituting the elastic layer of the collecting roller smaller than the density of the porous material constituting the elastic layer of the cleaning roller, the elastic layer of the collecting roller at the contact position between the cleaning roller and the collecting roller Can be made larger than the deformation amount of the elastic layer of the cleaning roller. Thus, as in the second aspect, the collection roller can collect more foreign matter from the cleaning roller.

  According to a fifth aspect of the present invention, in the cleaning device according to any one of the first to fourth aspects, the compressibility in the forming step of the porous material constituting the elastic layer of the recovery roller is determined by the elastic layer of the cleaning roller. It is made smaller than the compressibility in the formation process of the porous material which comprises.

  When forming a roller with a porous material, there exists a process of compressing a porous material. The higher the compressibility of the porous material at that time, the more the hardness of the porous material increases and it becomes difficult to deform. Conversely, the smaller the compressibility of the porous material, the smaller the hardness of the porous material and the easier it is to deform. According to the present invention, the collection roller can be easily deformed by reducing the compression rate of the porous material constituting the elastic layer of the collection roller. Accordingly, the deformation amount of the elastic layer of the recovery roller can be made larger than the deformation amount of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the recovery roller. It is possible to collect more foreign matter from the cleaning roller by the roller.

  According to a sixth aspect of the present invention, in the cleaning device according to any one of the first to fifth aspects, the amount of deformation of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the recovery roller is determined by the cleaning device. The amount of deformation of the elastic layer of the cleaning roller at the contact position between the roller and the charging roller is larger.

  The amount of deformation of the cleaning roller at the contact position between the cleaning roller and the collection roller is larger than the amount of deformation of the cleaning roller at the contact position between the cleaning roller and the charging roller. Can be delivered reliably.

  A seventh aspect of the present invention is the cleaning apparatus according to any one of the first to sixth aspects, wherein a contact pressure at a contact position between the cleaning roller and the recovery roller is determined by the cleaning roller and the charging roller. This is larger than the contact pressure at the contact position.

  The cleaning roller at the contact position between the cleaning roller and the collection roller is made larger than the contact pressure at the contact position between the cleaning roller and the charging roller. The deformation amount of the elastic layer can be made larger than the deformation amount of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the charging roller. As a result, the foreign matter removed by the cleaning roller can be reliably delivered to the collection roller.

  The invention according to claim 8 is the cleaning device according to any one of claims 1 to 7, wherein the charging roller, the cleaning roller, and the recovery roller are viewed from an axial direction, and the charging roller, The shaft centers of the cleaning roller and the collection roller are arranged on substantially the same straight line.

  By arranging the shaft centers of the charging roller, the cleaning roller, and the collection roller on substantially the same straight line, it is possible to cancel the deflection of the cleaning roller due to the cleaning roller coming into contact with the charging roller and the collection roller. Thereby, the cleaning roller can be stably brought into contact with the charging roller and the collection roller, and the cleaning performance can be improved.

  According to a ninth aspect of the invention, an image carrier, a charging roller for charging the surface of the image carrier, and a cleaning device for removing foreign matter on the surface of the charging roller are integrated at least integrally, and the main body of the image forming apparatus A process unit configured to be detachable from the apparatus includes the cleaning apparatus according to claim 1 as the cleaning apparatus.

  By adopting a detachable process unit in the image forming apparatus main body, maintenance work and replacement work are facilitated. In addition, since the process unit includes the cleaning device according to the present invention, the charging roller can be stably cleaned over a long period of time, so that it is possible to prevent the occurrence of defects such as charging failure and form a good image. Can be maintained.

  According to a tenth aspect of the present invention, there is provided an image carrier, an exposure device that exposes the surface of the image carrier to form an electrostatic latent image, and toner on the electrostatic latent image formed on the surface of the image carrier. A developing device for supplying and visualizing the image; a transfer device for transferring the visible image formed on the surface of the image carrier to a recording medium; and a fixing device for fixing the transferred image transferred to the recording medium to the recording medium. 9. The image forming apparatus comprising: a charging roller that charges the surface of the image bearing member; and a cleaning device that removes foreign matter on the surface of the charging roller. The cleaning device described is provided.

  Since the image forming apparatus includes the cleaning device according to the present invention, the charging roller can be stably cleaned over a long period of time. Can be maintained.

  According to the present invention, since the foreign matter removed from the charging roller by the cleaning roller is further recovered by the recovery roller, the cleaning capability of the cleaning roller can be maintained well over a long period of time. Further, since the cleaning roller and the collection roller are constituted by the porous roller, more foreign matters can be collected as compared with a brush roller or the like, and the holding ability of the collected foreign matters can be improved. Accordingly, it is possible to provide a cleaning device, a process unit, and an image forming apparatus that can stably exhibit good cleaning performance over a long period of time.

  FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. The image forming apparatus of the present invention shown in FIG. 1 includes four image forming units 1Y, 1C, 1C for forming an image with developers of different colors of yellow, cyan, magenta, and black corresponding to color separation components of a color image. 1M, 1Bk.

  The image forming units 1Y, 1C, 1M, and 1Bk have the same configuration except that they store different color toners. Therefore, the configuration of one image forming unit 1Y will be described as an example.

  The image forming unit 1Y includes a photosensitive drum 2 as an image carrier that carries an electrostatic latent image, a charging roller 3 that is disposed in contact with or close to the photosensitive drum 2 and charges the surface of the photosensitive drum 2. A developing device 4 that supplies toner to the electrostatic latent image on the surface of the photosensitive drum 2 to form a visible image; and a surface of the photosensitive drum 2 that is disposed in contact with the surface of the photosensitive drum 2. The cleaning blade 5 removes the residual toner adhering thereto, and the neutralizing lamp 6 removes the residual charge on the photosensitive drum 2. The components of the image forming unit 1Y are integrally held in a casing that is detachable from the image forming apparatus main body, and are configured as a process unit in which a plurality of image forming processes are integrated. .

  Above each of the image forming units 1Y, 1C, 1M, and 1Bk, an exposure device 7 that exposes the surface of the photosensitive drum 2 to form an electrostatic latent image is disposed. The exposure device 7 is configured to emit laser light from the laser diode to the surface of the photosensitive drum 2 based on the image data.

  Further, below each of the image forming units 1Y, 1C, 1M, and 1Bk, a transfer device 8 that transfers a visible image formed on the surface of the photosensitive drum 2 onto a transfer sheet as a recording medium is disposed. The transfer device 8 includes an intermediate transfer belt 12 stretched between a plurality of stretch rollers 9, 10, 11 composed of a drive roller and a driven roller, and four primary transfer rollers 13 </ b> Y facing the four photosensitive drums 2. 13C, 13M, and 13Bk, a secondary transfer roller 14 facing the stretching roller 10, and the like.

  The four primary transfer rollers 13Y, 13C, 13M, and 13Bk are pressed against the opposing photosensitive drum 2 via the intermediate transfer belt 12, and a primary transfer nip N1 is formed at the pressed position. The secondary transfer roller 14 is in pressure contact with the opposite stretching roller 10 via the intermediate transfer belt 12, and a secondary transfer nip N <b> 2 is formed at the pressed position.

  A paper feeding unit 15 is disposed at the lower part of the image forming apparatus. The paper feed unit 15 includes a paper feed cassette that can store a plurality of transfer papers P as recording media and a paper feed roller that carries the transfer paper P out of the paper feed cassette (not shown).

  In the image forming apparatus, there is a conveyance path R for guiding the transfer paper P delivered from the paper supply unit 15 to the discharge tray 19 provided outside the apparatus through the secondary transfer nip N2. Is formed.

  A pair of registration rollers 16a and 16b for temporarily stopping the transfer paper P sent out from the paper supply unit 15 and the transfer paper P are transported upstream of the secondary transfer nip N2 in the transfer paper transport direction. A transfer paper transport unit 17 is disposed.

  Further, a fixing device 18 for fixing the image on the transfer paper P is disposed downstream of the secondary transfer nip N2 in the transfer paper transport direction. The fixing device 18 includes, for example, a fixing roller 18a, a heating roller 18b having a heating source such as a heater therein, a fixing belt 18c stretched between the fixing roller 18a and the heating roller 18b, and a position facing the fixing roller 18a. The pressure roller 18d presses the fixing belt 18c. A fixing nip N3 is formed where the pressure roller 18d is in pressure contact with the fixing belt 18c.

The basic operation of the image forming apparatus will be described below with reference to FIG.
First, the image forming operation will be described using one image forming unit 1Y as an example. The photosensitive drum 2 of the image forming unit 1Y is rotated in the direction of the arrow in the figure, and the surface of the rotating photosensitive drum 2 is charged to a uniform high potential by the charging roller 3. Based on the image data, the surface of the photosensitive drum 2 is irradiated with a laser beam from the exposure device 7, and the potential of the irradiated portion is lowered to form an electrostatic latent image. The toner charged by the developing device 4 is electrostatically transferred to the portion of the surface of the photosensitive drum 2 where the electrostatic latent image is formed, whereby a yellow toner image (visible image) is formed on the photosensitive drum 2. ) Is formed.

  A voltage controlled to a polarity opposite to the toner charging polarity is applied to the primary transfer roller 13Y facing the photosensitive drum 2 of the image forming unit 1Y to form a transfer electric field in the primary transfer nip N1. Then, the toner image on the photosensitive drum 2 is primarily transferred to the intermediate transfer belt 12 that circulates in the direction of the arrow in the drawing by the action of the transfer electric field.

  In each of the other process units 1C, 1M, and 1Bk, a toner image is similarly formed on the photosensitive drum 2, and the four color toner images are primarily transferred to the intermediate transfer belt 12 so as to overlap each other.

  After the primary transfer, the toner remaining on the surface of each photosensitive drum 2 is removed by the cleaning blade 5. Thereafter, the charge remaining on the photosensitive drum 2 is removed by the charge eliminating lamp 6. Further, after the cleaning of the photosensitive drum 2 is finished, a lubricant is applied to the surface of the photosensitive drum 2 by a lubricant application device (not shown).

  On the other hand, the transfer paper P is sent out from the paper supply unit 15 to the conveyance path R by a paper supply signal from the control unit of the image forming apparatus. The transferred transfer paper P is temporarily stopped by the registration rollers 16a and 16b.

  After the toner images of the respective colors are primarily transferred to the intermediate transfer belt 12, the driving of the registration rollers 16a and 16b is resumed, and the transfer paper P is transferred to the secondary transfer sheet P at the timing (synchronization) with the toner images transferred to the intermediate transfer belt 12. Send to transfer nip N2.

  In the secondary transfer nip N2, a transfer electric field is formed by applying a voltage having a polarity opposite to the charging polarity of the toner to the secondary transfer roller. Alternatively, a similar transfer electric field may be formed by applying a voltage having the same polarity as the charging polarity of the toner to the stretching roller 10 facing the secondary transfer roller 14. Then, the toner image on the intermediate transfer belt 12 is secondarily transferred collectively onto the transfer paper P by the action of the transfer electric field formed in the secondary transfer nip N2.

  The transfer paper P onto which the toner image has been transferred is conveyed to the fixing device 18. When the transfer paper P passes through the fixing nip N3, the unfixed toner image on the transfer paper P is heated and pressurized and fixed to the transfer paper P. Thereafter, the transfer paper P is sent out from the fixing device 18 and discharged to the paper discharge tray 19.

Next, the configuration of the charging roller cleaning device, which is a feature of the present invention, will be described.
FIG. 2 is a schematic configuration diagram showing the first embodiment of the cleaning device 20 according to the present invention. As shown in FIG. 2, the cleaning device 20 includes a cleaning roller 21 and a collection roller 22.

  The cleaning roller 21 is disposed in contact with the surface of the charging roller 3, and the cleaning roller 21 rotates with the charging roller 3 as the charging roller 3 rotates. On the other hand, the collection roller 22 is disposed in contact with the surface of the cleaning roller 21. The collection roller 22 rotates with the rotating cleaning roller 21.

  The cleaning roller 21 is constituted by a porous roller in which an elastic layer 21b made of a porous material is arranged in a cylindrical shape on the outer periphery of the core material 21a. Similarly, the collection roller 22 is also constituted by a porous roller in which an elastic layer 22b made of a porous material is arranged in a cylindrical shape on the outer periphery of the core material 22a. A known porous material such as melamine foam can be applied to the porous material.

FIG. 3 is a schematic configuration diagram showing a second embodiment of the cleaning device according to the present invention.
As shown in FIG. 3A, the cleaning device 20 of the second embodiment also has a cleaning roller 21 that contacts the charging roller 3 and a recovery that contacts the cleaning roller 21 as in the first embodiment. A roller 22 is provided. In this embodiment, the thickness t2 of the elastic layer 22b of the collection roller 22 is formed to be thicker than the thickness t1 of the elastic layer 21b of the cleaning roller 21.

  FIG. 3B is an enlarged view of the contact position Z where the cleaning roller 21 and the collection roller 22 in FIG. 3A contact each other. At the contact position Z between the cleaning roller 21 and the collection roller 22, the elastic layers 21b and 22b are deformed (compressed) in the thickness direction. As described above, since the thickness t2 of the elastic layer 22b of the collection roller 22 is formed to be greater than the thickness t1 of the elastic layer 21b of the cleaning roller 21, the elastic layer 22b of the collection roller 22 at the contact position Z is formed. The deformation amount (compression amount) y <b> 2 is larger than the deformation amount (compression amount) y <b> 1 of the elastic layer 21 b of the cleaning roller 21.

  In FIG. 3A, the outer diameter of the collection roller 22 is formed larger than the outer diameter of the cleaning roller 21, but the core 22a of the collection roller 22 is formed as in the embodiment shown in FIG. By making the diameter smaller than the diameter of the core material 21a of the cleaning roller 21, the outer diameter of the cleaning roller 21 and the outer diameter of the recovery roller 22 are made substantially the same, and the thickness t2 of the elastic layer 22b of the recovery roller 22 Can be made thicker than the thickness t1 of the elastic layer 21b of the cleaning roller 21.

  Also in this case, as shown in FIG. 4B, the deformation amount y2 of the elastic layer 22b of the recovery roller 22 at the contact position Z where the cleaning roller 21 and the recovery roller 22 contact each other is It becomes larger than the deformation amount y1 of the elastic layer 21b.

  Further, in order to make the deformation amount y2 of the elastic layer 22b of the recovery roller 22 larger than the deformation amount y1 of the elastic layer 21b of the cleaning roller 21, the density of the porous material constituting the elastic layer 22b of the recovery roller 22 is You may make it smaller than the density of the porous material which comprises the elastic layer 21b of the cleaning roller 21. FIG.

  Moreover, when forming a roller with a porous material, there exists a process of compressing a porous material and increasing the hardness. The hardness of the porous material increases as the compressibility of the porous material at that time increases. Conversely, the smaller the compressibility of the porous material, the smaller the hardness of the porous material and the easier it is to deform. Therefore, the elastic layer 22b of the collecting roller 22 is made to have a compression rate smaller than that of the porous material forming the elastic layer 21b of the cleaning roller 21. The elastic layer 21b of the cleaning roller 21 can be more easily deformed. As described above, even when the compression rate of the porous material included in the collection roller 22 and the compression rate of the porous material included in the cleaning roller 21 are different from each other, the contact position Z between the cleaning roller 21 and the collection roller 22 The deformation amount y2 of the elastic layer 22b of the collection roller 22 can be made larger than the deformation amount y1 of the elastic layer 21b of the cleaning roller 21.

FIG. 5 is a schematic configuration diagram showing a third embodiment of the cleaning device according to the present invention.
As shown in FIG. 5A, the contact pressure at the contact position Z between the cleaning roller 21 and the collection roller 22 is made larger than the contact pressure at the contact position X between the cleaning roller 21 and the charging roller 3. ing. As a result, as shown in the enlarged view of FIG. 5B, the deformation amount (compression amount) y1 of the elastic layer 21b of the cleaning roller 21 at the contact position Z between the cleaning roller 21 and the collection roller 22 is set as the cleaning roller 21. The amount of deformation (compression amount) y3 of the elastic layer 21b of the cleaning roller 21 at the contact position X with the charging roller 3 is made larger.

FIG. 6 is a schematic configuration diagram showing a fourth embodiment of the cleaning device according to the present invention.
As shown in FIG. 6, in this embodiment, the charging roller 3, the cleaning roller 21, and the recovery roller 22 are viewed from the axial direction, and the charging roller 3 has an axial center 3 c, a cleaning roller 21 has an axial center 21 c, The shaft 22c of the roller 22 is disposed on substantially the same straight line L. In FIG. 6, the straight line L also passes through the axial center (not shown) of the photosensitive drum 2, but the straight line L may not pass through the axial center of the photosensitive drum 2. For example, as shown in FIG. 7, straight lines L passing through the shaft centers 3 c, 21 c, and 22 c of the charging roller 3, the cleaning roller 21, and the collection roller 22 are not shown in the drawing. You may arrange | position so that it may be substantially orthogonal to the straight line M which passes along an axial center.

  Although various embodiments of the cleaning device according to the present invention have been described above, in FIGS. 3 to 7, the configuration other than the configuration described above is the same as the configuration of the first embodiment shown in FIG. 2. Is omitted.

  Hereinafter, the operation of each embodiment of the cleaning device according to the present invention will be described by taking the embodiment of FIG. 2 as an example.

  In FIG. 2, when the charging roller 3 rotates in the direction of the arrow in the drawing, the cleaning roller 21 and the collection roller 22 are rotated in the direction indicated by the arrow in the drawing. At this time, the foreign matter attached to the surface of the charging roller 3 is removed by the cleaning roller 21 at the contact position between the charging roller 3 and the cleaning roller 21. The foreign matter removed by the cleaning roller 21 is collected in the elastic layer 21 b made of a porous material of the cleaning roller 21. Thereafter, the foreign matter collected by the cleaning roller 21 is collected by the elastic layer 22 b made of a porous material of the collection roller 22 at the contact position between the cleaning roller 21 and the collection roller 22.

  As described above, the cleaning device of the present invention collects the foreign matter removed by the cleaning roller 21 by the collection roller 22, so that the cleaning ability of the cleaning roller 21 can be well maintained over a long period of time. . In addition, since the cleaning roller 21 and the collection roller 22 are composed of porous rollers, more foreign matter can be collected compared to a brush roller or the like, and the collected foreign matter retention capability is excellent. Thereby, the cleaning device of the present invention can stably exhibit good cleaning performance.

  In the second embodiment shown in FIG. 3 or 4, the collection roller 22 is formed by forming the thickness t <b> 2 of the elastic layer 22 b of the collection roller 22 to be greater than the thickness t <b> 1 of the elastic layer 21 b of the cleaning roller 21. The deformation amount y2 of the elastic layer 22b is made larger than the deformation amount y1 of the elastic layer 21b of the cleaning roller 21. By increasing the deformation amount y2 of the elastic layer 22b of the collection roller 22, the foreign matter received from the cleaning roller 21 can be collected in the elastic layer 22b of the collection roller 22. Thereby, the collection roller 22 can collect more foreign substances. On the other hand, the cleaning roller 21 can prevent the foreign matter from being pushed into the elastic layer 21b by reducing the deformation amount y1 of the elastic layer 21b, and can successfully pass the foreign matter to the recovery roller 22. .

  Similarly, the elastic layer 22b of the recovery roller 22 can also be reduced by making the density of the porous material that constitutes the elastic layer 22b of the recovery roller 22 smaller than the density of the porous material that constitutes the elastic layer 21b of the cleaning roller 21. The recovery roller 22 can recover a larger amount of foreign matter from the cleaning roller 21. The recovery can also be achieved by making the compression rate in the formation process of the porous material constituting the elastic layer 22b of the recovery roller 22 smaller than the compression rate in the formation process of the porous material constituting the elastic layer 21b of the cleaning roller 21. The elastic layer 22b of the roller 22 can be greatly deformed to collect more foreign matter.

  Further, as in the third embodiment described with reference to FIG. 5, the deformation amount y1 of the cleaning roller 21 at the contact position Z between the cleaning roller 21 and the collection roller 22 is determined as the contact position between the cleaning roller 21 and the charging roller 3. By making it larger than the deformation amount y3 of the cleaning roller 21 at X, the foreign matter removed by the cleaning roller 21 can be reliably delivered to the collection roller 22.

  Further, as in the fourth embodiment described with reference to FIG. 6 or FIG. 7, the axes 3 c, 21 c, 22 c of the charging roller 3, the cleaning roller 21, and the collection roller 22 are arranged on substantially the same straight line L. Can cancel the bending of the cleaning roller 21 caused by the cleaning roller 21 coming into contact with the charging roller 3 and the collection roller 22. Thereby, the cleaning roller 21 can be stably brought into contact with the charging roller 3 and the collection roller 22, and the cleaning performance can be improved.

  While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. In FIG. 1, the cleaning apparatus according to the present invention is mounted on a so-called tandem indirect transfer type color image forming apparatus, but direct transfer type image formation in which an image formed on a photosensitive drum is directly transferred to transfer paper. The present invention can also be applied to an apparatus, a so-called revolver type color image forming apparatus that sequentially forms images of respective colors on one photosensitive drum, or other image forming apparatuses. In addition, a photosensitive belt or the like can be applied instead of the photosensitive drum as an image carrier that carries an electrostatic latent image.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus according to the present invention. It is a schematic structure figure showing a 1st embodiment of a cleaning device concerning the present invention. It is a schematic block diagram which shows 2nd Embodiment of the cleaning apparatus which concerns on this invention, (A) is a whole block diagram, (B) is a principal part enlarged view. It is a schematic block diagram which shows the modification of the said 2nd Embodiment, (A) is a whole block diagram, (B) is a principal part enlarged view. It is a schematic block diagram which shows 3rd Embodiment of the cleaning apparatus which concerns on this invention, (A) is a whole block diagram, (B) is a principal part enlarged view. It is a schematic block diagram which shows 4th Embodiment of the cleaning apparatus which concerns on this invention. It is a schematic block diagram which shows the modification of the said 4th Embodiment.

Explanation of symbols

2 Photosensitive drum 3 Charging roller 3c Axis 4 Development device 7 Exposure device 8 Transfer device 18 Fixing device 20 Cleaning device 21 Cleaning roller 21a Core material 21b Elastic layer 21c Axis 22 Recovery roller 22a Core material 22b Elastic layer 22c Axis L Straight line t1 Thickness t2 Thickness X Contact position y1 Deformation amount y2 Deformation amount y3 Deformation amount Z Contact position

Claims (10)

A cleaning roller that contacts a charging roller that charges the surface of the image carrier to remove foreign matter on the surface of the charging roller; and a recovery roller that contacts the cleaning roller and collects the foreign matter removed by the cleaning roller. A cleaning device,
The cleaning device, wherein the cleaning roller and the recovery roller are constituted by a porous roller in which an elastic layer made of a porous material is formed on an outer periphery of a core material.   The deformation amount of the elastic layer of the recovery roller at the contact position between the cleaning roller and the recovery roller is larger than the deformation amount of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the recovery roller. The cleaning apparatus according to claim 1, which is configured as described above.   The cleaning device according to claim 1, wherein the elastic layer of the recovery roller is thicker than the elastic layer of the cleaning roller.   4. The cleaning device according to claim 1, wherein the density of the porous material constituting the elastic layer of the recovery roller is smaller than the density of the porous material constituting the elastic layer of the cleaning roller.   The compression rate in the formation process of the porous material constituting the elastic layer of the recovery roller is smaller than the compression rate in the formation process of the porous material constituting the elastic layer of the cleaning roller. 2. The cleaning device according to item 1.   The deformation amount of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the recovery roller is larger than the deformation amount of the elastic layer of the cleaning roller at the contact position between the cleaning roller and the charging roller. The cleaning apparatus according to claim 1, wherein the cleaning apparatus is configured as described above.   The contact pressure at the contact position between the cleaning roller and the collection roller is set larger than the contact pressure at the contact position between the cleaning roller and the charging roller. Cleaning device.   2. The shafts of the charging roller, the cleaning roller, and the collecting roller are arranged on substantially the same straight line in a state where the charging roller, the cleaning roller, and the collecting roller are viewed from the axial direction. 8. The cleaning device according to any one of items 1 to 7. The image bearing member, a charging roller that charges the surface of the image bearing member, and a cleaning device that removes foreign matter on the surface of the charging roller are at least integrally formed and can be attached to and detached from the image forming apparatus main body. Process unit
9. A process unit comprising the cleaning device according to claim 1 as the cleaning device. An image carrier, a charging roller for charging the surface of the image carrier, an exposure device for exposing the surface of the image carrier to form an electrostatic latent image, and a static image formed on the surface of the image carrier. A developing device that supplies toner to a visible image by supplying toner to the electrostatic latent image, a transfer device that transfers a visible image formed on the surface of the image carrier to a recording medium, and a recording medium that transfers the transferred image transferred to the recording medium In an image forming apparatus provided with a fixing device for fixing to a surface and a cleaning device for removing foreign matter on the surface of the charging roller,
An image forming apparatus comprising the cleaning device according to claim 1 as the cleaning device.

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