JP2007094239A - Cleaning apparatus, charging device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning apparatus capable of preventing defective cleaning on a part to be cleaned, and to provide a charging device, a process cartridge and an image forming apparatus. <P>SOLUTION: Regarding the cleaning apparatus equipped with a cleaning roller 2 for cleaning a charging roller (a cleaning object part) 5 in contact with the charging roller 5, the charging roller 5 is cylindrical, and regarding the outer circumferential surface of the roller 5, the center part in the axial direction projects outward as compared with each axial end part, the cleaning roller 2 is cylindrical, and regarding the outer circumferential surface of the roller 2, the center part in the axial direction is dented inward as compared with each axial end part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning device, a charging device, a process cartridge, and an image forming apparatus.

  Patent Document 1 discloses a technique including a charging member (cleaning target portion) that charges the surface of a photoconductor and a cleaning member that contacts the charging member and cleans the surface of the charging member. In such a technique, the charging member has a configuration in which an elastic member is wound around the metal shaft, and both ends of the metal shaft are pressed against the photoconductor with an appropriate pressing force to charge the surface of the photoconductor. Yes.

  However, when the metal shaft has low rigidity, the center of the charging member may bend inward, and a gap may be formed between the charging member and the photosensitive member, resulting in poor charging. In order to prevent this, it is conceivable that the center of the charging member has a drum shape in which the outer peripheral surface protrudes outward from both end portions in the axial direction in anticipation of the deflection.

Japanese Patent No. 3100625

  However, when the charging member is formed into a drum shape as described above, there is a problem that a gap is formed between the charging member and the cleaning member at both ends of the charging member, and defective cleaning is likely to occur. In particular, when the cleaning member is provided at a position opposite to the photosensitive member, the amount of deflection of the charging member is added in addition to the drum shape, so that the gap between the end portions becomes larger and the contact failure becomes worse. Become.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning device, a charging device, a process cartridge, and an image forming apparatus that can prevent defective cleaning of a portion to be cleaned.

  In order to solve the above-described problem, the invention described in claim 1 is a cleaning device including a cleaning unit that contacts the cleaning target unit and cleans the cleaning target unit, and the cleaning target unit is cylindrical. In addition, the outer peripheral surface protrudes outward from both ends in the axial direction, the cleaning portion is cylindrical, and the outer peripheral surface is recessed inward from the both ends in the axial direction. Features.

  According to a second aspect of the present invention, in the first aspect of the present invention, the cleaning unit includes a resin foam.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the cleaning unit rotates with the rotation of the cleaning target unit.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the cleaning device includes a driving unit, and the cleaning unit is rotated by rotational driving of the driving unit.

  The invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the cleaning target portion is a charging member.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the charging member is not in contact with the surface of the image carrier.

  According to a seventh aspect of the present invention, in the invention of the sixth aspect, the charging member is provided with a gap holding portion that secures a gap with the image carrier, and the cleaning portion abuts against the gap holding portion. It is characterized by.

  The invention described in claim 8 is a process cartridge including the charging device according to any one of claims 5 to 7.

  The invention described in claim 9 is an image forming apparatus including the charging device according to any one of claims 5 to 7.

  According to the present invention, the shape of the cleaning part is recessed inward from the both ends of the outer peripheral surface in accordance with the shape of the object to be cleaned in which the outer peripheral surface protrudes outward from both ends. As a result, it is difficult to form a gap between the cleaning target portion and the cleaning member, and the dirt adhering to the cleaning target portion can be cleaned cleanly, and defective cleaning can be prevented.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a main part of an image forming apparatus according to an embodiment of the present invention, showing a photosensitive member, a charging roller, and a cleaning member. FIG. 2 is a sectional view showing a process cartridge of the image forming apparatus shown in FIG. FIG. 3 is a cross-sectional view showing the overall configuration of the image forming apparatus.

  The image forming apparatus 100 according to the present embodiment is provided above the image forming unit 20, the paper feeding unit 10 provided at the lower part of the main body, the image forming unit 20 disposed substantially at the center of the main body of the apparatus. An image reading unit 30. Further, in a space between the image forming unit 20 and the image reading unit 30, a paper discharge storage unit 40 on which sheets on which image formation has been completed is stacked is arranged.

  Unused paper is stored in the paper supply unit 10, and the uppermost paper is sent out from the paper supply cassette by the rotation of the paper supply roller 15 and conveyed to the registration roller 17. The registration roller 17 starts to rotate at a timing so that the conveyance of the sheet conveyed from the sheet cassette is temporarily stopped and the positional relationship between the toner image on the surface of the photosensitive member and the leading end of the sheet becomes a predetermined position. To be controlled.

  The image reading unit 30 is provided with a reading traveling body 19 including a light source for illuminating a document and a mirror, and performs reading scanning of the document placed on the contact glass 21 by the reciprocating movement of the reading traveling body 19. Image information scanned by the reading traveling body 21 is read as an image signal into the CCD 25 installed behind the lens 23. The read image signal is digitized and processed. Based on the image-processed signal, an electrostatic latent image is formed on the surface of the photoreceptor 3 by light emission of a laser diode (not shown) of the exposure device 7. The optical signal from the laser diode reaches the photosensitive member 3 through a known polygon mirror or lens.

  In the image forming unit 20, a charging roller (charging member (cleaning target)) 5 that is charged around the surface of the photosensitive member 3 and rotated by a driving motor around the drum-shaped photosensitive member (image carrier) 3. An exposure device 7 for irradiating the surface of the photoconductor with laser light with image information, a developing device 9 for visualizing the electrostatic latent image formed by exposure on the surface of the photoconductor 3, and a toner image developed on the photoconductor 3 A transfer device 11 that transfers to a sheet, a cleaning blade 13 that removes and collects toner remaining on the surface of the photoreceptor after transfer, and the like are arranged. The developing device 9 uses polymerized toner as a developer.

  The photoreceptor 3, the charging roller 5, the developing device 9, the cleaning blade 13, and the like disposed in the image forming unit 20 are incorporated in one unit as a process cartridge 50. The image forming unit 20 is provided with a fixing device 14 for fixing the toner on the paper on which the toner image is obtained on the downstream side of the paper conveyance path. The sheet that has passed through the fixing device 14 is discharged and stored in the discharge storage unit 40 via the discharge roller 16. The charging roller 5 has a drum shape in which the outer peripheral surface 5a protrudes outward from the both ends in the axial direction.

  Next, the cleaning roller (cleaning unit (cleaning device)) 2 for cleaning the surface of the charging roller 5 will be described. The cleaning roller 2 is formed by coating a metal shaft (core metal) 2a having a diameter of about 4 mm with a melamine foam resin 2b with a predetermined thickness, and the diameter of the roller is about 8.5 mm. As shown in FIG. 1, the cleaning roller 3 has an outer peripheral surface 2 c in a zigzag shape that is gradually recessed inward from both axial end portions toward the central portion. Bearings 29 are fitted into both ends of the cleaning roller 2, and one end of a compression spring 27 is attached to the bearing 29. The cleaning roller 2 is rotated along with the rotation of the charging roller 5. The other end of the spring 27 is attached to and supported by the housing portion of the process cartridge 50. The cleaning roller 2 is biased toward the charging roller 5 by the compression spring 27, and the outer peripheral surface of the cleaning roller 2 is in contact with the outer peripheral surface of the charging roller 5.

  Next, operations and effects of the cleaning device according to the present embodiment will be described. During image formation, the charging roller 5 is rotated to charge the surface of the photoreceptor 3. When the charging roller 5 rotates, the cleaning roller 2 rotates along with the rotation of the charging roller 5 to clean the surface of the charging roller 5.

  In the present embodiment, the charging roller 5 and the cleaning roller 2 are formed in accordance with the drum shape of the charging roller 5, since the shape of the cleaning roller 2 is a zigzag shape in which the outer peripheral surface 2c is recessed inward from the both ends. It is difficult to form a gap between the charging roller 2 and the charging roller 5 can be stably cleaned.

  Since the cleaning roller 2 is provided with the melamine foam resin 2b, the toner on the surface of the charging roller 5 can be stored in the pores of the foam resin, and the toner scraped off by the roller can be prevented from scattering.

  Since a polymerized toner is used as a toner for the developer, the image quality is excellent because the particle size is uniform with a small particle size compared to a pulverized toner obtained by crushing resin into particles.

  Since the cleaning roller 2 rotates along with the charging roller 5, no separate driving means for the cleaning roller 2 is required, and the configuration is simple.

  Next, an experiment was conducted on the cleaning removal effect of the cleaning roller 2 in the above-described configuration, and the result will be described. Using the above-described zipped cleaning roller 2 as an example, and using a conventional cylindrical cleaning roller as a comparative example, paper passing evaluation was performed. In addition, the paper passing conditions used the remodeling machine (made by Ricoh Co., Ltd.) of Imagio Color8200 as an experimental machine. In addition, 5% chart paper was used as a paper passing image, and 5000 sheets were passed through 100 continuous sheets as one cycle.

  As a method for evaluating the cleaning performance, after passing the paper, in a low-temperature and low-humidity environment at a temperature of 10 ° C. and a humidity of 15%, a 1200 dpi halftone image having a high detection capability against dirt on the charging roller 5 is output. The presence or absence of abnormal images was determined. As a result of the experiment, an abnormal image was observed in the cylindrical cleaning member as a comparative example, but no abnormal image was observed in the zipped cleaning roller 2 of the present invention.

  As described above, the generation of the abnormal image was not observed in the zipped cleaning roller 2 of the present invention because the cleaning roller 2 was formed in a zigzag shape in accordance with the drum shape of the charging roller 5. This is because it is difficult to form a gap between the charging roller 5 and the cleaning roller 2.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. In the above-described embodiment, the cleaning roller 2 is rotated with the rotation of the charging roller 5. However, the present invention is not limited to this, and a motor (driving means) is connected to the shaft 2 a of the cleaning roller 2 to clean the cleaning roller 2. You may make it rotate. Since the cleaning roller 2 is driven by a motor, the surface of the charging roller 5 can be reliably cleaned by the cleaning roller 2 because it is harder to slide than when the cleaning roller 2 is rotated along with the charging roller 5.

  In the above-described embodiment, the cleaning roller 2 is rotated along with the rotation of the charging roller 5. However, the present invention is not limited to this. A gear is provided between the charging roller 5 and the cleaning roller 2, and the The rotation of the charging roller 5 may be transmitted to the cleaning roller 2.

  In the above-described embodiment, the surface of the cleaning roller 2 is brought into contact with the surface of the charging roller 5. However, the present invention is not limited to this, and a gap tape (gap holding portion) 31 is wound around both ends of the charging roller 5. Also good. In this case, since the surface of the photosensitive member 3 contacts the gap tape 31, a minute gap 33 is formed between the surface of the charging roller 5 and the surface of the photosensitive member 3, and the surface of the photosensitive member 3 is contaminated with the charging roller 5. Therefore, the life of the charging roller 5 can be extended. Further, since the surface of the cleaning roller 2 abuts against the gap tape 31, a minute gap 35 is formed between the surface of the cleaning roller 2 and the surface of the charging roller 5, and the toner adhering to the surface of the charging roller 5 is effectively removed. Can be scraped off.

  In the above-described embodiment, the cleaning target portion is the charging roller 5. However, the present invention is not limited to this, and the cleaning target portion may be the photoreceptor 3 or the transfer device 11.

1 is a perspective view showing a main part of an image forming apparatus according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a process cartridge of the image forming apparatus shown in FIG. 3. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus. It is a perspective view which shows the principal part of the image forming apparatus which concerns on the modification of this invention.

Explanation of symbols

2 Cleaning roller 3 Photoconductor (image carrier)
5 Charging roller (cleaning target part)
31 Gap tape (gap holding part)
50 Process cartridge 100 Image forming apparatus

Claims (9)

  A cleaning device provided with a cleaning unit that abuts against a cleaning target part and cleans the cleaning target part. The cleaning target part is cylindrical and the outer peripheral surface protrudes outward from both ends in the axial direction. The cleaning device has a cylindrical shape, and the outer peripheral surface is recessed inward at the center portion from both end portions in the axial direction.   The cleaning device according to claim 1, wherein the cleaning unit includes a resin foam.   The cleaning device according to claim 1, wherein the cleaning unit rotates with the rotation of the cleaning target unit.   The cleaning apparatus according to claim 1, wherein the cleaning apparatus includes a driving unit, and the cleaning unit is rotated by rotational driving of the driving unit.   The charging device, wherein the cleaning target portion is a charging member, and the cleaning device is the cleaning device according to any one of claims 1 to 4.   6. The charging device according to claim 5, wherein the charging member is not in contact with the surface of the image carrier.   The charging device according to claim 6, wherein the charging member is provided with a gap holding portion that secures a gap with the image carrier, and the cleaning portion is in contact with the gap holding portion.   A process cartridge comprising the charging device according to claim 5. An image forming apparatus comprising the charging device according to claim 5.

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