JP4935194B2 - Cleaning device - Google Patents

Description

The present invention relates to a cleaning device for cleaning the surface of the charging roller for charging the surface of the image bearing member.

  Conventionally, as a charging device for an image forming apparatus such as a copying machine or a printer adopting an electrophotographic method, a device using a corona discharge phenomenon such as a scorotron charger has been widely used, but a charging device using a corona discharge phenomenon is used. In this case, the generation of ozone and nitrogen oxides that have a negative effect on the human body and the global environment is a problem. In contrast, the contact charging method in which a conductive charging roll or the like is in direct contact with the photosensitive member to charge the photosensitive member generates less ozone and nitrogen oxides and has good power efficiency. It has become mainstream.

  In such a contact charging method, since dirt such as toner and external additives easily adheres to the charging roll, a configuration in which a film-shaped or sheet-shaped cleaning member capable of bending deformation is brought into surface contact with the charging roll is disclosed. (For example, see Patent Document 1).

  However, it is difficult for the fixed film-like or sheet-like cleaning member to efficiently collect the foreign matter removed from the charging roll, and the charging roll is damaged by adhesion to the charging roll due to the accumulation of foreign matter or the accumulated foreign matter. A problem occurs that shortens the life of the charging roll.

  In addition, as a cleaning member for the charging roll, a film-like polyethylene terephthalate is attached to a base such as a sponge with a double-sided tape, and the cleaning member frictionally charges to the same polarity as the toner when rubbed against the charging roll. Thus, a configuration is disclosed in which toner is prevented from accumulating on the cleaning member (see, for example, Patent Document 2).

However, if the cleaning member is triboelectrically charged to the same polarity as the toner, there is no action of collecting contaminants, and the cleaning effect on the surface of the charging roll cannot be obtained sufficiently. In addition, when a sponge is used for the cleaning member, it is necessary to penetrate to the surface of the charging roll to some extent due to its configuration, the contact pressure increases, and the contact width increases. For this reason, contaminants removed from the surface of the charging roll accumulate in the contact nip of the cleaning member, and it adheres to the charging roll and the cleaning member or damages the charging roll due to accumulated foreign matter, thereby prolonging the life of the charging roll. Failure to shorten occurs.
Japanese Patent Laid-Open No. 2005-24575 JP-A-6-202447

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning device that can efficiently clean the surface of the charging roll and suppress the occurrence of scratches on the charging roll.

The invention according to claim 1 is a cleaning device comprising a cleaning member that contacts the charging roll that charges the surface of the image carrier and cleans the surface of the charging roll, wherein the cleaning member An upstream cleaning unit provided on the upstream side in the rotation direction and in contact with the charging roll; and a downstream cleaning unit provided on the downstream side in the rotation direction of the charging roll and in contact with the charging roll, the upstream cleaning unit And the downstream cleaning section are formed of different frictionally charged materials, and the upstream cleaning section and the downstream cleaning section are supported by a film member .

According to the first aspect of the present invention, the cleaning member includes an upstream cleaning unit that contacts the charging roll on the upstream side in the rotation direction of the charging roll, and a downstream cleaning unit that contacts the charging roll on the downstream side in the rotation direction. In addition, the upstream side cleaning unit and the downstream side cleaning unit are made of different frictionally charged materials. By adjusting the triboelectric charge train, the upstream cleaning unit collects contaminants (toner, external additives, etc.) on the cleaning member due to friction with the contaminants, and the downstream cleaning unit collects the contaminants on the charging roll. It becomes possible to return. Thereby, contamination of the charging roll can be efficiently suppressed. Therefore, sticking to the charging roll and generation of scratches due to the accumulation of foreign matter between the cleaning member and the charging roll are suppressed, and the life of the charging roll can be extended.
Moreover, since the upstream side cleaning part and the downstream side cleaning part are supported by the film member, the upstream side cleaning part and the downstream side cleaning part can be brought into contact with the charging roll at a low pressure, and a physical action can be imparted. Space saving and cost reduction are possible.

According to a second aspect of the present invention , there is provided a cleaning device including a cleaning member that contacts the charging roll that charges the surface of the image carrier and cleans the surface of the charging roll, wherein the cleaning member is a member of the charging roll. An upstream cleaning unit provided on the upstream side in the rotation direction and in contact with the charging roll; and a downstream cleaning unit provided on the downstream side in the rotation direction of the charging roll and in contact with the charging roll, the upstream cleaning unit And the downstream cleaning section are formed of different materials of a triboelectric charge train, and the upstream cleaning section and the downstream cleaning section are formed of a film member .

According to the second aspect of the present invention, the cleaning member includes an upstream cleaning unit that contacts the charging roll on the upstream side in the rotation direction of the charging roll, and a downstream cleaning unit that contacts the charging roll on the downstream side in the rotation direction. In addition, the upstream side cleaning unit and the downstream side cleaning unit are made of different frictionally charged materials. By adjusting the triboelectric charge train, the upstream cleaning unit collects contaminants (toner, external additives, etc.) on the cleaning member due to friction with the contaminants, and the downstream cleaning unit collects the contaminants on the charging roll. It becomes possible to return. Thereby, contamination of the charging roll can be efficiently suppressed. Therefore, sticking to the charging roll and generation of scratches due to the accumulation of foreign matter between the cleaning member and the charging roll are suppressed, and the life of the charging roll can be extended.
Moreover, since the upstream side cleaning part and the downstream side cleaning part are composed of film members, the upstream side cleaning part and the downstream side cleaning part can be brought into contact with the charging roll at a low pressure, and a physical action can be imparted. Space saving and cost reduction are possible.

According to a third aspect of the present invention, there is provided a cleaning device comprising a cleaning member that contacts the charging roll that charges the surface of the image carrier and cleans the surface of the charging roll, wherein the cleaning member includes An upstream cleaning unit provided on the upstream side in the rotation direction and in contact with the charging roll; and a downstream cleaning unit provided on the downstream side in the rotation direction of the charging roll and in contact with the charging roll, the upstream cleaning unit And the downstream cleaning section have different surface characteristics, and the upstream cleaning section and the downstream cleaning section are supported by a film member .

According to the third aspect of the present invention, the cleaning member includes an upstream cleaning unit that contacts the charging roll on the upstream side in the rotation direction of the charging roll, and a downstream cleaning unit that contacts the charging roll on the downstream side in the rotation direction. Thus, the upstream side cleaning unit and the downstream side cleaning unit have different surface characteristics. By adjusting the surface characteristics, it becomes possible to collect contaminants (toner, external additives, etc.) in the cleaning member in the upstream cleaning unit, and return the contaminants to the charging roll in the downstream cleaning unit. Thereby, contamination of the charging roll can be efficiently suppressed. Therefore, sticking to the charging roll and generation of scratches due to the accumulation of foreign matter between the cleaning member and the charging roll are suppressed, and the life of the charging roll can be extended.
Moreover, since the upstream side cleaning part and the downstream side cleaning part are supported by the film member, the upstream side cleaning part and the downstream side cleaning part can be brought into contact with the charging roll at a low pressure, and a physical action can be imparted. Space saving and cost reduction are possible.

According to a fourth aspect of the present invention , there is provided a cleaning device comprising a cleaning member that contacts the charging roll that charges the surface of the image carrier and cleans the surface of the charging roll, wherein the cleaning member is a member of the charging roll. An upstream cleaning unit provided on the upstream side in the rotation direction and in contact with the charging roll; and a downstream cleaning unit provided on the downstream side in the rotation direction of the charging roll and in contact with the charging roll, the upstream cleaning unit And the downstream side cleaning unit have different surface characteristics, and the upstream side cleaning unit and the downstream side cleaning unit are made of a film member .

According to the fourth aspect of the invention, the cleaning member includes an upstream cleaning unit that contacts the charging roll on the upstream side in the rotation direction of the charging roll, and a downstream cleaning unit that contacts the charging roll on the downstream side in the rotation direction. Thus, the upstream side cleaning unit and the downstream side cleaning unit have different surface characteristics. By adjusting the surface characteristics, it becomes possible to collect contaminants (toner, external additives, etc.) in the cleaning member in the upstream cleaning unit, and return the contaminants to the charging roll in the downstream cleaning unit. Thereby, contamination of the charging roll can be efficiently suppressed. Therefore, sticking to the charging roll and generation of scratches due to the accumulation of foreign matter between the cleaning member and the charging roll are suppressed, and the life of the charging roll can be extended.
Moreover, since the upstream side cleaning part and the downstream side cleaning part are composed of film members, the upstream side cleaning part and the downstream side cleaning part can be brought into contact with the charging roll at a low pressure, and a physical action can be imparted. Space saving and cost reduction are possible.

  According to the present invention, sticking to the charging roll and generation of scratches due to accumulation of foreign matters between the cleaning member and the charging roll can be suppressed, and the life of the charging roll can be extended.

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

  FIG. 1 shows an image forming apparatus 100 according to the first embodiment of the present invention.

  The image forming apparatus 100 performs image processing based on color image information sent from an image data input device such as a personal computer (not shown), and forms a color image on a recording sheet P by an electrophotographic method.

  The image forming apparatus 100 includes image forming units 10Y, 10M, 10C, and 10K that form toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). In the following, when it is necessary to distinguish YMCK, description will be made by adding any of Y, M, C, and K after the reference. When YMCK does not need to be distinguished, Y, M, C, K is omitted.

  The image forming units 10Y, 10M, 10C, and 10K are arranged so that the image forming units 10Y, 10M, 10C, and 10K move in the traveling direction of the endless intermediate transfer belt 30 that is stretched by the backup roll 34 and the plurality of stretch rolls 32. They are arranged in series in the order of 10K. Further, the intermediate transfer belt 30 is provided with primary transfer rolls 16Y, which are arranged to face the photosensitive drums 12Y, 12M, 12C, and 12K as image carriers of the image forming units 10Y, 10M, 10C, and 10K, respectively. It is inserted between 16M, 16C and 16K.

  Next, the configuration of each of the image forming units 10Y, 10M, 10C, and 10K and the image forming operation will be described using the image forming unit 10Y that forms a yellow toner image as a representative.

  A charging roll 24Y is disposed in contact with the surface of the photosensitive drum 12Y, and the surface of the photosensitive drum 12Y is uniformly charged by the charging roll 24Y. Next, image exposure corresponding to the yellow image is performed by the exposure device 14Y, and an electrostatic latent image corresponding to the yellow image is formed on the surface of the photosensitive drum 12Y.

  The electrostatic latent image corresponding to the yellow image is developed by the toner carried on the developing roll 18Y to which the developing bias of the developing device 15Y is applied, and becomes a yellow toner image. The yellow toner image is primarily transferred onto the intermediate transfer belt 30 by the pressing force of the primary transfer roll 16Y and the electrostatic attraction force by the transfer bias applied to the primary transfer roll 16Y.

  In this primary transfer, the entire yellow toner image is not transferred to the intermediate transfer belt 30, and a part of the yellow toner image remains on the photosensitive drum 12Y as transfer residual yellow toner. Further, an external additive of toner is also attached to the surface of the photosensitive drum 12Y. After the primary transfer, the photosensitive drum 12Y passes through a position facing the cleaning device 20Y, and transfer residual toner and the like on the surface of the photosensitive drum 12Y are removed. Thereafter, the surface of the photosensitive drum 12Y is charged again by the charging roll 24Y for the next image forming cycle.

  As shown in FIG. 1, in the image forming apparatus 100, the image forming process similar to the above is performed at each image forming unit 10Y at a timing in consideration of the relative position difference between the image forming units 10Y, 10M, 10C, and 10K. , 10M, 10C, and 10K, and Y, M, C, and K color toner images are sequentially superimposed on the intermediate transfer belt 30 to form a multiple toner image.

  Then, electrostatic attraction of the secondary transfer roll 36 to which the transfer bias is applied to the recording paper P conveyed to the secondary transfer position where the intermediate transfer belt 30 and the secondary transfer roll 36 face each other at a predetermined timing. The multiple toner images are collectively transferred from the intermediate transfer belt 30 to the recording paper P by the force.

  The recording paper P to which the multiple toner images have been transferred is separated from the intermediate transfer belt 30, and then conveyed to the fixing device 31, where it is fixed to the recording paper P by heat and pressure, thereby forming a full color image.

  The transfer residual toner on the intermediate transfer belt 30 that has not been transferred to the recording paper P is collected by the intermediate transfer belt cleaner 33.

In the image forming apparatus 100, as shown in FIG. 2, a charging roll 24 is disposed above the photosensitive drum 12 so as to come into contact with the photosensitive drum 12. The charging roll 24 has a charging layer 24B formed around a conductive shaft 24A. A predetermined high voltage is applied to the shaft 24A from a power source (not shown).
A motor (not shown) is connected to the support shaft of the photosensitive drum 12, and the photosensitive drum 12 is driven to rotate clockwise (in the direction of arrow 2) in FIG. Further, the charging roll 24 rotates in the direction of the arrow 4 following the rotation of the photosensitive drum 12.

  A cleaning member 40 as a cleaning device that cleans the surface of the charging roll 24 is disposed on the charging roll 24. The cleaning member 40 includes a film member 42 as a support, and the film member 42 is supported by a frame (not shown) at both ends in the longitudinal direction of the charging roll 24. The film member 42 is provided with an upstream electrode 44 that contacts the charging roll 24 on the upstream side in the rotation direction of the charging roll 24 and a downstream electrode 46 that contacts the charging roll 24 on the downstream side in the rotation direction of the charging roll 24. ing. In other words, the upstream electrode 44 is provided in the upstream nip region where the charging roll 24 rotates and enters the nip region with the cleaning member 40, and the downstream electrode 46 rotates in the cleaning member 40 when the charging roll 24 rotates. In the downstream nip region away from the contact nip region. The upstream electrode 44 and the downstream electrode 46 are disposed at a predetermined interval, and are disposed at the full width in the longitudinal direction of the charging roll 24.

  The upstream electrode 44 is applied with a bias (positive in the present embodiment) having a polarity opposite to the charging polarity of the toner (negative in the present embodiment) from the DC power supply 48. Further, a bias (negative in this embodiment) having the same polarity as the charging polarity of the toner is applied to the downstream electrode 46 from the DC power supply 50. The bias applied from the DC power supply 48 is set to 800V to 1000V, for example, and the bias applied from the DC power supply 50 is set to −800V to −1000V, for example. For the upstream electrode 44 and the downstream electrode 46, for example, a conductive resin in which conductive powder or the like is mixed with a resin is used in addition to a metal.

  In addition, an insulating sheet is used for the film member 42, and for example, polyethylene, polypropylene, polyester, or the like is used. Further, the thickness of the film member 42 is, for example, 200 μm, and the thicknesses of the upstream electrode 44 and the downstream electrode 46 are set to, for example, 500 μm. In FIG. 2, the thicknesses of the upstream electrode 44 and the downstream electrode 46 are emphasized more than the actual thickness for easy understanding of the configuration.

  Next, details of the charging roll 24 will be described.

  The charging roll 24 is obtained by sequentially forming a conductive elastic layer and a surface layer as a charging layer 24B on a conductive shaft 24A.

  The diameter of the charging roll 24 is 7 mm to 15 mm, more preferably 8 mm to 14 mm, and the thickness of the charging layer 24B is preferably 2 mm to 4 mm. If the diameter is 15 mm or more, the number of times of contact with the external additive per location on the peripheral surface is reduced, and the number of discharges is reduced. This is disadvantageous from the viewpoint of miniaturization, although it has excellent long-term stability against dirt and charging performance. . If the diameter is 7 mm or less, the image forming apparatus 100 can be downsized, which is advantageous. However, the number of times of contact with the external additive per peripheral surface increases and the number of discharges increases, which is disadvantageous for long-term stability. It becomes.

  The charging roll 24 is not limited to the following configuration as long as it has a predetermined charging performance.

  As the material of the shaft 24A, free-cutting steel, stainless steel or the like is used. The material and the surface treatment method are appropriately selected according to the application such as slidability, and the non-conductive material is generally plated. It may be processed by an appropriate process and a conductive process may be performed.

  The conductive elastic layer constituting the charging layer 24B of the charging roll 24 may be, for example, an elastic material such as rubber having elasticity, a conductive material such as carbon black or ion conductive material for adjusting the resistance of the conductive elastic layer, and the like. Accordingly, materials that can be usually added to rubber, such as softeners, plasticizers, curing agents, vulcanizing agents, vulcanization accelerators, anti-aging agents, and fillers such as silica and calcium carbonate, may be added. It is formed by coating the peripheral surface of the conductive shaft 24A with a mixture in which a material usually added to rubber is added. As a conductive agent for the purpose of adjusting the resistance value, a material in which a material that conducts electricity using electrons and / or ions as a charge carrier, such as carbon black or an ionic conductive agent blended in a matrix material, is used. it can. The elastic material may be a foam.

  The elastic material constituting the conductive elastic layer is formed, for example, by dispersing a conductive agent in a rubber material. Rubber materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide. -Allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber, natural rubber and the like, and blended rubbers thereof. Among these, silicone rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, acrylonitrile-butadiene copolymer rubber, and blended rubbers thereof are preferably used. These rubber materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used. Examples of electronic conductive agents include carbon blacks such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; tin oxide, indium oxide, titanium oxide Examples thereof include fine powders such as various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals Can be mentioned.

  The surface layer constituting the charging layer 24B is formed for the purpose of preventing contamination due to foreign matters such as toner, and the surface layer material may be any of resin, rubber, etc. It is not limited. Polyester, polyimide, copolymer nylon, silicone resin, acrylic resin, polyvinyl butyral, ethylene tetrafluoroethylene copolymer, melamine resin, fluoro rubber, epoxy resin, polycarbonate, polyvinyl alcohol, cellulose, polyvinylidene chloride, polyvinyl chloride, polyethylene And ethylene vinyl acetate copolymer. Of these, polyvinylidene fluoride, a tetrafluoroethylene copolymer, polyester, polyimide, and copolymer nylon are preferably used from the viewpoint of contamination of the external additive.

  The surface layer can contain a conductive material to adjust the resistance value. The conductive material preferably has a particle size of 3 μm or less. In addition, as a conductive agent for the purpose of adjusting the resistance value, it electrically conducts electrons and / or ions as charge carriers, such as carbon black, conductive metal oxide particles, or ionic conductive agent blended in the matrix material. What disperse | distributed material etc. can be used.

  In addition, a fluorine-based or silicone-based resin is preferably used for the surface layer. In particular, it is preferably composed of a fluorine-modified acrylate polymer. Further, fine particles may be added to the surface layer. As a result, the surface layer becomes hydrophobic and acts to prevent the foreign matter from adhering to the charging roll 24. In addition, insulating particles such as alumina and silica are added to provide irregularities on the surface of the charging roll 24, thereby reducing the burden at the time of rubbing against the photosensitive drum 12, and the charging roll 24 and the photosensitive drum. It is also possible to improve the mutual wear resistance.

  Next, the operation of the image forming apparatus 100 will be described.

  If contaminants such as toner and external additives adhere to the surface of the photosensitive drum 12 after passing through the cleaning device 20, the contaminants adhere to the charging roll 24 by the rotation of the photosensitive drum 12, and this charging Contaminants on the surface of the roll 24 are sent to the contact nip area with the cleaning member 40 by the rotation of the charging roll 24.

  At that time, in the upstream nip region where the cleaning member 40 and the charging roll 24 are in contact with each other, since a bias having a polarity opposite to that of the toner is applied to the upstream electrode 44, the contaminant is collected by the cleaning member 40 and cleaned. In the contact nip region between the member 40 and the charging roll 24, the contaminants are aggregated to some extent. In the downstream nip region where the cleaning member 40 and the charging roll 24 are in contact with each other, a bias having the same polarity as the toner is applied to the downstream electrode 46, so that the aggregated contaminant is returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. For this reason, the contamination of the charging roll 24 can be efficiently suppressed. Accordingly, it is possible to suppress sticking to the charging roll 24 and generation of scratches due to the accumulation of foreign matter between the film member 42 and the charging roll 24, and to extend the life of the charging roll 24.

  Next, an image forming apparatus according to a second embodiment of the present invention will be described.

  In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 3, in this image forming apparatus, a cleaning member 60 as a cleaning device for cleaning the charging roll 24 is disposed above the charging roll 24. The cleaning member 60 includes a film member 62, and the film member 62 is supported by frames (not shown) at both ends of the charging roll 24. On the surface of the film member 62, a film-like upstream cleaning unit 64 that comes into contact with the charging roll 24 on the upstream side in the rotation direction of the charging roll 24 is attached, and contacts the charging roll 24 on the downstream side in the rotation direction of the charging roll 24. A film-like downstream cleaning section 66 is attached. That is, the upstream cleaning unit 64 is attached to the upstream nip region where the charging roll 24 rotates and enters the contact nip region with the cleaning member 60, and the downstream cleaning unit 66 is rotated when the charging roll 24 rotates. Affixed to the downstream nip region away from the contact nip region with the cleaning member 60.

  The upstream side cleaning unit 64 and the downstream side cleaning unit 66 are formed of different materials of the triboelectric charge train. In this embodiment, the upstream cleaning unit 64 is formed of a positively charged column material that is positively charged with a polarity opposite to that of the toner, and the downstream cleaning unit 66 is a negatively charged column that is negatively charged with the same polarity as that of the toner. Made of material. For example, nylon, polypropylene, polyester, or the like is used for the upstream side cleaning unit 64 of the positively charged column. For example, PTFE, PVDC, polyimide, or the like is used for the downstream side cleaning unit 66 of the negatively charged column. Further, the upstream side cleaning unit 64 and the downstream side cleaning unit 66 are provided at the full width in the longitudinal direction of the charging roll 24 at a predetermined interval.

  Here, triboelectric charge is a combination of materials that rub and determines which is positive (+) and which is negative (-). A material in which materials that easily rub against each other and are easily charged positively (+) and materials that are easily charged negatively (−) is referred to as a frictional charge train (charging sequence). In other words, the triboelectric charge train is a sequence of those that easily emit electrons or those that easily receive electrons. A substance having a close positional relationship in the triboelectric charge train has a small charge amount due to friction, and becomes larger as the distance increases.

  Moreover, the thickness of the film member 62 is 200 micrometers, for example, and the thickness of the upstream cleaning part 64 and the downstream cleaning part 66 is set to 200 micrometers, for example. In FIG. 3, the thicknesses of the upstream-side cleaning unit 64 and the downstream-side cleaning unit 66 are expressed with emphasis more than the actual thickness in order to make the configuration easy to understand.

  In such an image forming apparatus, contaminants such as toner and external additives remaining on the surface of the photosensitive drum 12 adhere to the charging roll 24, and contaminants on the surface of the charging roll 24 are caused by rotation of the charging roll 24. It is sent to the contact nip region with the cleaning member 60. In the upstream nip region where the cleaning member 60 and the charging roll 24 are in contact with each other, the upstream cleaning unit 64 is charged positively with a polarity opposite to that of the toner due to friction with the contaminant, and the contaminant is collected by the cleaning member 60. . In the downstream nip region where the cleaning member 60 and the charging roll 24 are in contact, the downstream cleaning unit 66 is negatively charged with the same polarity as the toner, and the contaminant is returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. Thereby, contamination of the charging roll 24 can be efficiently suppressed. Accordingly, it is possible to suppress sticking to the charging roll 24 and generation of scratches due to the accumulation of foreign matter between the cleaning member 60 and the charging roll 24, and to extend the life of the charging roll 24.

  Next, an image forming apparatus according to a third embodiment of the present invention will be described.

  In addition, the same code | symbol is attached | subjected to the member same as 1st or 2nd embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, the image forming apparatus is provided with a cleaning member 70 as a cleaning device for cleaning the charging roll 24. The cleaning member 70 includes a film member 72, and the film member 72 is supported by frames (not shown) at both ends of the charging roll 24. On the surface of the film member 72, a film-like upstream cleaning unit 74 that contacts the charging roll 24 on the upstream side in the rotation direction of the charging roll 24 is attached, and contacts the charging roll 24 on the downstream side in the rotation direction of the charging roll 24. A film-like downstream cleaning section 76 is attached. That is, the upstream cleaning unit 74 is attached to the upstream nip region where the charging roll 24 rotates and enters the contact nip region with the cleaning member 70, and the downstream cleaning unit 76 is rotated when the charging roll 24 rotates. Affixed to the downstream nip region away from the contact nip region with the cleaning member 70.

  The upstream cleaning unit 74 and the downstream cleaning unit 76 are set to different surface roughnesses, and the surface roughness of the downstream cleaning unit 76 is set to be smaller than the surface roughness of the upstream cleaning unit 74. Further, the upstream side cleaning unit 74 and the downstream side cleaning unit 76 are arranged so as to be adjacent to each other, and are provided in the full width in the longitudinal direction of the charging roll 24.

  Here, the surface roughness is a ten-point average surface roughness and is a surface roughness defined in JIS B0601 (1994). In the present embodiment, the surface roughness of the upstream cleaning unit 74 is set to, for example, 6 μm or more, preferably 10 μm or more, and the surface roughness of the downstream cleaning unit 76 is, for example, 5 μm or less, preferably 3 μm or less. Is set.

  The ten-point average surface roughness Rz can be measured using a surface roughness measuring instrument or the like, but in this embodiment, a contact-type surface roughness measuring device in an environment of 23 ° C. and 55 RH%. (Surfcom 570A, manufactured by Tokyo Seimitsu Co., Ltd.) was used. When measuring the surfaces of the upstream side cleaning unit 74 and the downstream side cleaning unit 76, the measurement distance is 2.5 mm, and the tip of the contact needle is diamond (5 μmR, 90 ° cone), and the location is changed to 3 The average value at the time of repeated measurement was determined as the ten-point average surface roughness Rz.

  In such an image forming apparatus, contaminants such as toner and external additives remaining on the surface of the photosensitive drum 12 adhere to the charging roll 24, and contaminants on the surface of the charging roll 24 are caused by rotation of the charging roll 24. It is sent to the contact nip area with the cleaning member 70. In the upstream nip region between the cleaning member 70 and the charging roll 24, the surface roughness of the upstream cleaning unit 74 is large, so that contaminants are likely to adhere, and the contaminants are collected by the cleaning member 70. Further, in the downstream nip region, since the surface roughness of the downstream cleaning unit 76 is small, the contaminant is difficult to adhere, and the contaminant is returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. Thereby, contamination of the charging roll 24 can be efficiently suppressed. Therefore, it is possible to suppress sticking to the charging roll 24 and generation of scratches due to the accumulation of foreign matter between the cleaning member 70 and the charging roll 24, and to extend the life of the charging roll 24.

  Next, an image forming apparatus according to a fourth embodiment of the present invention will be described.

  In addition, the same code | symbol is attached | subjected to the member same as 1st-3rd embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 5, in this image forming apparatus, a cleaning member 80 as a cleaning device for cleaning the charging roll 24 is disposed above the charging roll 24. The cleaning member 80 includes a film member 82, and the film member 82 is supported by frames (not shown) at both ends of the charging roll 24. On the surface of the film member 82, a film-like upstream cleaning portion 84 that contacts the charging roll 24 on the upstream side in the rotation direction of the charging roll 24 is attached, and contacts the charging roll 24 on the downstream side in the rotation direction of the charging roll 24. A film-like downstream cleaning portion 86 is attached. That is, the upstream cleaning unit 84 is adhered to the upstream nip region where the charging roll 24 rotates and enters the contact nip region with the cleaning member 80, and the downstream cleaning unit 86 is rotated by the charging roll 24 rotating. Affixed to the downstream nip region away from the contact nip region with the cleaning member 80.

  The upstream cleaning unit 84 and the downstream cleaning unit 86 have different surface characteristics, and the surface energy of the downstream cleaning unit 86 is set smaller than the surface energy of the upstream cleaning unit 84. That is, the configuration is such that the release property of the downstream cleaning unit 86 is superior to the release property of the upstream cleaning unit 84. In the present embodiment, for example, polypropylene or polyester is used for the upstream side cleaning unit 84, and PTFE, PVDC, or the like is used for the downstream side cleaning unit 86, for example. Further, the upstream side cleaning unit 84 and the downstream side cleaning unit 86 are arranged so as to be adjacent to each other, and are provided in the full width in the longitudinal direction of the charging roll 24.

  In such an image forming apparatus, contaminants such as toner and external additives remaining on the surface of the photosensitive drum 12 adhere to the charging roll 24, and contaminants on the surface of the charging roll 24 are caused by rotation of the charging roll 24. It is sent to the contact nip area with the cleaning member 80. In the upstream nip region where the cleaning member 80 and the charging roll 24 are in contact with each other, the surface energy of the upstream cleaning portion 84 is large and the releasability is not good, so that contaminants are collected by the cleaning member 80. Further, in the downstream nip region, the surface energy of the downstream cleaning unit 86 is small and the releasability is good, so that the contaminant is returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. Thereby, contamination of the charging roll 24 can be efficiently suppressed. Therefore, it is possible to suppress sticking to the charging roll 24 and generation of scratches due to the accumulation of foreign matters between the cleaning member 80 and the charging roll 24, and to extend the life of the charging roll 24.

  Next, an image forming apparatus according to a fifth embodiment of the present invention will be described.

  In addition, the same code | symbol is attached | subjected to the member same as 1st-4th embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 6, the image forming apparatus is provided with a cleaning member 110 as a cleaning device for cleaning the charging roll 24. The cleaning member 110 has a shape in which the end edges of the two film members 112 and 114 are bonded and bent into an L shape. The film members 112 and 114 each come into contact with the charging roll 24, so that the cleaning member 110 has two shapes. It is configured to come into contact with the surface of the charging roll 24 at the contact portion.

  The film member 112 is disposed in the upstream nip region where the charging roll 24 rotates and enters the contact nip region with the cleaning member 110, and the film member 114 rotates in the contact nip with the cleaning member 110 when the charging roll 24 rotates. Located in the downstream nip region away from the region. That is, the film member 112 constitutes an upstream cleaning portion, and the film member 114 constitutes a downstream cleaning portion. The thickness of the film members 112 and 114 is set to 300 μm, for example.

  The film members 112 and 114 are set to have different surface roughnesses, and the surface roughness of the film member 114 is set to be smaller than the surface roughness of the film member 112. The film members 112 and 114 are arranged so as to contact the surface of the charging roll 24 with the full width in the longitudinal direction of the charging roll 24.

  Here, the surface roughness is a ten-point average surface roughness and is a surface roughness defined in JIS B0601 (1994). In the present embodiment, the surface roughness of the film member 112 is set to, for example, 6 μm or more, preferably 10 μm or more, and the surface roughness of the film member 114 is set to, for example, 5 μm or less, preferably 3 μm or less. .

  In such a cleaning member 110, since the film members 112 and 114 are brought into contact with the charging roll 24 at two contact portions, the contact area is increased as compared with the case where the planar film member is brought into contact with the charging roll 24. be able to. At this time, since the surface roughness of the film member 112 is large in the upstream nip region, contaminants are easily attached, and the contaminants are collected by the film member 112. In the downstream nip region, since the surface roughness of the film member 114 is small, the contaminants are difficult to adhere, and the contaminants are returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. Since the cleaning member 110 is brought into contact with the charging roll 24 at two contact portions, the cleaning member 110 can be stably cleaned for a long time, and the cleaning property is improved.

  Next, an image forming apparatus according to a sixth embodiment of the present invention will be described.

  In addition, the same code | symbol is attached | subjected to the member same as 1st-5th embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 7, the image forming apparatus is provided with a cleaning member 120 as a cleaning device for cleaning the charging roll 24. The cleaning member 120 has a shape in which the edges of the two film members 122 and 124 are bonded and bent into an L shape, and the film member 122 and 124 are brought into contact with the surface of the charging roll 24 at two contact sites. Yes.

  The film member 122 is disposed in the upstream nip region where the charging roll 24 rotates and enters the contact nip region with the cleaning member 120, and the film member 124 rotates in the contact nip with the cleaning member 120 when the charging roll 24 rotates. Located in the downstream nip region away from the region. That is, the film member 122 constitutes an upstream cleaning portion, and the film member 124 constitutes a downstream cleaning portion.

  The film members 122 and 124 are set to different surface energies, and the surface energy of the film member 124 is set smaller than the surface energy of the film member 122. The film members 122 and 124 are disposed so as to contact the surface of the charging roll 24 with the full width in the longitudinal direction of the charging roll 24.

  In such a cleaning member 120, since the film members 122 and 124 are brought into contact with the charging roll 24 at two contact portions, the contact area is increased as compared with the case where the planar film member is brought into contact with the charging roll 24. be able to. At that time, since the surface energy of the film member 122 is large in the upstream nip region, the contaminant is easily attached, and the contaminant is collected by the film member 122. In the downstream nip region, since the surface roughness of the film member 124 is small, the contaminants are difficult to adhere, and the contaminants are returned to the charging roll 24. The contaminants returned to the charging roll 24 are returned to the photosensitive drum 12 and collected by the cleaning device 20 and the developing device 15 of the photosensitive drum 12. Since the cleaning member 120 is brought into contact with the charging roll 24 at two contact sites, the cleaning member 120 can be stably cleaned for a long period of time, and the cleaning property is improved.

  6 and 7, the cleaning members 110 and 120 are configured to contact the charging roll 24 at two contact sites. However, the present invention is not limited to this configuration. It may be configured to contact the charging roll 24. For example, a configuration in which the film-shaped cleaning member is formed in an inverted U shape so as to contact the charging roll 24 at three locations, or a configuration in which the inner curved surface of the arc-shaped cleaning member is in contact with the charging roll 24 may be employed.

  The image forming apparatus 100 shown in FIG. 1 has a configuration in which image forming units 10Y, 10M, 10C, and 10K of yellow, magenta, cyan, and black are arranged in parallel along the moving direction of the intermediate transfer belt 30. The configuration is not limited to this. For example, the cleaning device of the present invention can be applied to a configuration in which a toner image is formed on a photosensitive drum by repeating a four-cycle operation using a rotary developing device.

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a configuration diagram showing a charging roll cleaning device used in the image forming apparatus shown in FIG. 1. FIG. 6 is a configuration diagram illustrating a charging roll cleaning device used in an image forming apparatus according to a second embodiment of the present invention. FIG. 6 is a configuration diagram illustrating a charging roll cleaning device used in an image forming apparatus according to a third embodiment of the present invention. FIG. 10 is a configuration diagram illustrating a charging roll cleaning device used in an image forming apparatus according to a fourth embodiment of the present invention. It is a block diagram which shows the cleaning apparatus of the charging roll used for the image forming apparatus which concerns on 5th Embodiment of this invention. It is a block diagram which shows the cleaning apparatus of the charging roll used for the image forming apparatus which concerns on 6th Embodiment of this invention.

Explanation of symbols

10Y, 10M, 10C, 10K Image forming units 12Y, 12M, 12C, 12K Photosensitive drum (image carrier)
24 charging roll 24A shaft 24B charging layer 40 cleaning member 42 film member (support)
44 upstream electrode 46 downstream electrode 48 DC power supply 50 DC power supply 60 cleaning member 62 film member 64 upstream cleaning unit 66 downstream cleaning unit 70 cleaning member 72 film member 74 upstream cleaning unit 76 downstream cleaning unit 80 cleaning member 82 Film member 84 Upstream cleaning unit 86 Downstream cleaning unit 100 Image forming apparatus 110 Cleaning member 112 Film member 114 Film member 120 Cleaning member 122 Film member 124 Film member

Claims (4)

A cleaning device comprising a cleaning member that contacts a charging roll that charges the surface of the image carrier and cleans the surface of the charging roll,
The cleaning member is provided on the upstream side in the rotation direction of the charging roll and is in contact with the charging roll, and the downstream cleaning unit is provided on the downstream side in the rotation direction of the charging roll and is in contact with the charging roll. With
The upstream cleaning portion and the downstream cleaning portion are formed of different frictionally charged train materials,
The cleaning apparatus, wherein the upstream cleaning section and the downstream cleaning section are supported by a film member . A cleaning device comprising a cleaning member that contacts a charging roll that charges the surface of the image carrier and cleans the surface of the charging roll,
The cleaning member is provided on the upstream side in the rotation direction of the charging roll and is in contact with the charging roll, and the downstream cleaning unit is provided on the downstream side in the rotation direction of the charging roll and is in contact with the charging roll. With
The upstream cleaning portion and the downstream cleaning portion are formed of different frictionally charged train materials,
The cleaning apparatus, wherein the upstream cleaning section and the downstream cleaning section are formed of a film member . A cleaning device comprising a cleaning member that contacts a charging roll that charges the surface of the image carrier and cleans the surface of the charging roll,
The cleaning member is provided on the upstream side in the rotation direction of the charging roll and is in contact with the charging roll, and the downstream cleaning unit is provided on the downstream side in the rotation direction of the charging roll and is in contact with the charging roll. With
The upstream cleaning unit and the downstream cleaning unit have different surface characteristics,
The cleaning apparatus, wherein the upstream cleaning section and the downstream cleaning section are supported by a film member . A cleaning device comprising a cleaning member that contacts a charging roll that charges the surface of the image carrier and cleans the surface of the charging roll,
The cleaning member is provided on the upstream side in the rotation direction of the charging roll and is in contact with the charging roll, and the downstream cleaning unit is provided on the downstream side in the rotation direction of the charging roll and is in contact with the charging roll. With
The upstream cleaning unit and the downstream cleaning unit have different surface characteristics,
The cleaning apparatus, wherein the upstream cleaning section and the downstream cleaning section are formed of a film member .

Images