JP5776245B2 - Conductive member, charging device, process cartridge, and image forming apparatus - Google Patents

Description

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

  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, ozone or nitrogen oxides may be generated. In contrast, the contact charging method in which a conductive member that is a charging member such as a conductive charging roll is brought into direct contact with the image carrier to charge the image carrier significantly generates ozone, nitrogen oxides, and the like. It has become mainstream recently because of its low power efficiency.

  The charging member is usually a member in which an elastic layer, a surface layer, and the like are sequentially formed as a charging layer on a conductive core. In such a charging member, it has been studied to improve the adhesion between the conductive core and the elastic layer.

  For example, in Patent Document 1, (1) a liquid addition-reaction type silicone rubber mixture in which functional groups for addition reaction are silicon atom-bonded hydrogen atoms and vinyl groups is supplied to the peripheral surface of a metal shaft core. And a step of covering the peripheral surface of the shaft core with an addition reaction type silicone rubber layer, and (2) a step of curing the addition reaction type silicone rubber layer to form an elastic layer. In the method, the addition reaction type in which the step (1) has a surface temperature of 60 ° C. to 160 ° C. and a temperature of 0 ° C. to 15 ° C. on the peripheral surface of the shaft core body. A step of supplying a silicone rubber mixture, and the ratio of the number of moles of silicon-bonded hydrogen atoms to the number of moles of vinyl groups in the addition-reactive silicone rubber mixture is 2.0 or more and 6.0 or less. Silicone by elastic roll manufacturing method An elastic roll with good adhesion to the core of the silicone rubber elastic layer can be obtained while suppressing a decrease in elasticity of the elastic layer over time, and the shaft core body of the elastic roll is made of aluminum, stainless steel, iron, Alternatively, it is described that any of these alloys, or those plated with chromium or nickel is used.

JP 2009-198909 A

  An object of the present invention is to provide a conductive member that can suppress the occurrence of image quality defects when used in an image forming apparatus even when stored in a high temperature and high humidity environment for a long period of time.

The invention according to claim 1 has a conductive core having a hole on the surface and a conductive elastic layer formed on the conductive core, and the conductive core is in the hole. to have a methacrylic acid ester or a cured product of the sodium silicate, the methacrylic acid ester is 1 to 30 alkyl carbon atoms, a conductive member is methacrylic acid ester of an alkene or alkyne.

  The invention according to claim 2 is the conductive member according to claim 1, wherein the conductive elastic layer contains a resin containing chlorine.

  The invention according to claim 3 is the conductive member according to claim 1, wherein the conductive elastic layer contains a conductive agent containing chlorine.

  According to a fourth aspect of the present invention, the conductive member is a charging member that charges the surface of the image carrier in the image forming apparatus, or a developed toner image on the surface of the image carrier in the image forming apparatus. The conductive member according to claim 1, which is a transfer member to be transferred.

  The invention which concerns on Claim 5 is a charging device provided with the electroconductive member of any one of Claims 1-3.

  The invention according to claim 6 is a process cartridge comprising an image carrier and the conductive member according to any one of claims 1 to 3 that charges a surface of the image carrier.

  According to a seventh aspect of the present invention, there is provided an image carrier, a conductive member according to any one of claims 1 to 3 that charges the surface of the image carrier, and a latent image on the surface of the image carrier. An image forming apparatus comprising: a latent image forming unit for forming; and a developing unit for developing a latent image formed on the surface of the image holding member with toner to form a toner image.

  According to the first aspect of the present invention, even when the conductive core body does not have a cured product of methacrylic acid ester or sodium silicate in the hole portion, it can be stored in a high temperature and high humidity environment for a long time. An electroconductive member that suppresses the occurrence of image quality defects when used in an image forming apparatus is provided.

  According to the second aspect of the present invention, image quality defects may occur when the conductive elastic layer is used in an image forming apparatus even when stored in a high temperature and high humidity environment for a long time as compared with a case where the conductive elastic layer does not contain a resin containing chlorine. There is provided a conductive member that is more effective in suppressing the occurrence of.

  According to the third aspect of the present invention, when the conductive elastic layer does not contain a conductive agent containing chlorine, the image quality is high when used in an image forming apparatus even when stored in a high temperature and high humidity environment for a long time. There is provided a conductive member that is more effective in suppressing the occurrence of defects.

  According to the invention of claim 4, even when the conductive core is not impregnated with methacrylic acid ester or sodium silicate, the image can be stored even in a high temperature and high humidity environment for a long time. Provided is a conductive member as a charging member or a transfer member that suppresses occurrence of image quality defects when used in a forming apparatus.

  According to the invention which concerns on Claim 5, compared with the case where the electroconductive core of an electroconductive member is not what the impregnation process by methacrylic acid ester or sodium silicate was given, an electroconductive member is high-temperature high-humidity environment for a long period of time. Provided is a charging device that can suppress the occurrence of image quality defects when stored in an image forming apparatus even when stored below.

  According to the invention which concerns on Claim 6, compared with the case where the electroconductive core of an electroconductive member is not what the impregnation process by methacrylic acid ester or sodium silicate was given, an electroconductive member is high temperature high humidity environment for a long time. Even when stored below, a process cartridge is provided in which occurrence of image quality defects is suppressed when used in an image forming apparatus.

  According to the seventh aspect of the present invention, the conductive member has a high temperature and high humidity environment over a long period of time as compared with the case where the conductive core of the conductive member is not impregnated with methacrylic acid ester or sodium silicate. There is provided an image forming apparatus in which occurrence of image quality defects is suppressed even when stored below.

It is a side view showing a schematic structure of an example of a charging device using a conductive member according to an embodiment of the present invention. It is a front view which shows schematic structure of an example of the charging device using the electroconductive member which concerns on embodiment of this invention. It is a schematic structure figure showing an example of a process cartridge concerning an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Conductive member and charging device>
The shape of the conductive member according to the present embodiment is not particularly limited, and examples thereof include a roll shape, a brush shape, a belt (tube) shape, and a blade shape. Among these, a roll shape (a conductive roll such as a so-called charging roll or transfer roll) is preferable. Hereinafter, on the assumption that the conductive member according to the present embodiment is a charging roll as a charging member, a conductive core, a charging layer including a conductive elastic layer, etc. will be described. The same applies to conductive members of other shapes.

  FIG. 1 is a side view illustrating a schematic configuration of an example of a charging device including a conductive member according to the present embodiment. FIG. 2 is a front view illustrating a schematic configuration of an example of a charging device including the conductive member according to the present embodiment. A charging device 1 shown in FIG. 1 is a charging member that charges the surface of an image carrier provided in an image forming apparatus, and is a cylindrical charging member that rotates about an axis. And a cleaning roll 12 which is a charging member cleaning member for cleaning the surface of the charging roll 10. The charging roll 10 includes a conductive core body 14 having a hole on the surface, and a charging layer 16 formed on the outer periphery of the conductive core body 14. The charging layer 16 has a conductive elastic layer, and a surface layer or the like is formed as necessary. The cleaning roll 12 includes a core body 18 and a cylindrical elastic layer 20 formed on the outer periphery of the core body 18.

  As shown in FIG. 2, in the charging device 1, the charging roll 10 includes a coil spring 26 and the like installed at both ends of the conductive core 14 with respect to the photoreceptor 24 that is an image holding member of an electrophotographic image forming apparatus. The elastic member is pressed against the surface of the photoconductor 24 and is driven by the photoconductor 24. On the other hand, the cleaning roll 12 is held by a bearing 28 at a bearing distance between the conductive core 14 of the charging roll 10 and the core 18 of the cleaning roll 12, and the cleaning roll 12 is charged with a predetermined amount of biting. Follow 10 The charging roll 10 and the cleaning roll 12 may be driven by the photosensitive member 24 and the charging roll 10, respectively, or may be driven separately.

  Using a resin such as epichlorohydrin as a conductive elastic layer of a conductive member such as a charging roll or transfer roll, or a rubber material containing a quaternary ammonium salt or a metal salt as a conductive agent, from the viewpoint of resistance uniformity and high image quality It is advantageous. However, especially when the resin, quaternary ammonium salt or metal salt that can impart good resistance contains chlorine, etc., especially when stored under high humidity or when dew condensation occurs, this chlorine and the moisture in the air May react to produce corrosive components such as hydrochloric acid. This corrosive component such as hydrochloric acid may corrode the conductive core through, for example, defects such as holes such as pinholes in the plating of the conductive core, fine pore defects in the oxide film, and the like. A portion where the conductive core is corroded may cause peeling of the conductive elastic layer or blistering, which may cause image quality defects.

  The present inventors have provided a conductive member in a high-temperature and high-humidity environment for a long period of time by having a cured product of methacrylic acid ester or sodium silicate in the hole portion such as the above-mentioned hole or fine hole defect of the conductive core. It has been found that even when stored below, occurrence of image quality defects is suppressed when used in an image forming apparatus. As a method for forming a cured product of methacrylic acid ester or sodium silicate in the hole, for example, a method of impregnating a conductive core having a hole with a treatment liquid containing methacrylic acid ester or sodium silicate and curing it. Is mentioned. In particular, even when the conductive elastic layer contains a resin containing chlorine, the conductive elastic layer contains a conductive agent containing chlorine, etc., the conductive member is kept in a high temperature and high humidity environment for a long time. It has been found that even when stored, the occurrence of image quality defects is suppressed when used in an image forming apparatus. This is because the impregnation treatment seals holes such as pinholes such as plating of the conductive core and micropore defects in the oxide film, and corrosive components such as hydrochloric acid when stored in a high temperature and high humidity environment for a long time. Even if it produces | generates, it is thought that corrosion of a conductive core, peeling of a conductive elastic layer, swelling, etc. are suppressed.

  Examples of the methacrylic acid ester include methacrylic acid esters of alkyl, alkene, and alkyne having 1 to 30 carbon atoms, and among these, from 2 to 20 carbon atoms in terms of workability in the impregnation treatment step. It is preferred to use alkyl, alkene, alkyne methacrylates. Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, Examples include tridecyl methacrylate, stearyl methacrylate, 2-hydroxypropyl methacrylate, ethylene glycol dimethacrylate, trimethylolpropane ethylene glycol trimethacrylate, and the like. One of these may be used, or a mixture may be used. Moreover, you may use another additive with methacrylic acid ester. Examples of the additive include other known monomer components, polymerization initiators, polymerization inhibitors, and the like.

  In the impregnation treatment with methacrylic acid ester or sodium silicate, for example, the conductive core is used for 1 minute or more in a vacuum state of 1.0 kPa or less using an impregnation apparatus BS-200A manufactured by Central Research Laboratory, Inc. After vacuuming for 1 minute or less and immersing in methacrylic acid ester or sodium silicate, immersing and pressing at 0.1 MPa or more and 10 MPa or less for 1 minute or more and 60 minutes or less, washing with water, then 70 ° C or more and 120 ° C or less What is necessary is just to carry out hot water hardening or hot-air hardening for 1 minute or more and 120 minutes or less. Thereafter, if necessary, it may be dried using a centrifuge and cooled.

  Examples of the material of the conductive core 14 include at least aluminum, SUS, iron, or an alloy thereof, or a material in which these are plated with chromium or nickel.

  Examples of the resin constituting the conductive elastic layer constituting the charging layer 16 of the charging roll 10 include hydrin resins such as epichlorohydrin rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, and the like. In addition, isoprene rubber, chloroprene rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile- Examples thereof include elastic materials (rubber materials) such as butadiene copolymer rubber (NBR), natural rubber, and blend rubbers thereof. These rubber materials may be foamed or non-foamed.

  As the rubber material, epichlorohydrin rubber or acrylonitrile-butadiene copolymer rubber (NBR) is preferable from the viewpoint of resistance or the like, but it may have appropriate conductivity by adding a conductive agent such as an ionic conductive agent. You may use it not only in this.

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 And 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 quaternary ammonium salts (for example, tetraethylammonium, lauryltrimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, benzyltriethylammonium, Perchlorates such as benzyltributylammonium, benzyltrioctylammonium, denatured fatty acid and dimethylethylammonium, chlorate, borofluoride, sulfate, ethosulphate, benzyl halide (benzyl bromide, chloride) Benzyl salts, etc.), aliphatic sulfonates, higher alcohol sulfates, higher alcohol ethylene oxide addition sulfates, high Alcohol phosphate ester salts, higher alcohol ethylene oxide addition phosphates, various betaine, higher alcohol ethylene oxide, polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid ester and the like. Furthermore, as organic ion conductive substances, polyhydric alcohols (1,4 butanediol, ethylene glycol, polyethylene glycol, propylene glycol, polyethylene glycol, etc.) and their derivatives and metal salts, monools (ethylene glycol monomethyl ether, And a complex of an ethylene glycol monoethyl ether or the like) and a metal salt. Examples of the metal salt include LiClO ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiBF ₄ , NaClO ₄ , NaSCN, KSCN, NaCl, and other Group 1 metal salts; electrolytes such as NH ₄ ⁺ salts; Metals belonging to Group 2 of the periodic table such as Ca (ClO ₄ ) ₂ and Ba (ClO ₄ ) ₂ ; activity to react with isocyanates such as at least one hydroxyl group, carboxyl group, primary or secondary amine group And those having a group having hydrogen; and the like. Specific examples of such a complex include PEL (a complex of LiClO ₄ and polyethylene glycol).

  These conductive agents may be used alone or in combination of two or more. Further, the amount of addition is not particularly limited, but in the case of the electronic conductive agent, it is preferably in the range of 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the rubber material. In the case of an agent, it is preferably in the range of 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber material.

  As the conductive agent, an ionic conductive agent is preferable from the viewpoint of resistance uniformity and the like, and among them, quaternary ammonium chloride, quaternary ammonium perchlorate and the like are preferably used from the viewpoints of handleability, versatility, low resistance, cost, and the like. . In addition, a metal salt containing chloride or perchlorate may be used.

  In this embodiment, the conductive elastic layer contains a resin containing chlorine such as epichlorohydrin, and the conductive elastic layer contains a conductive agent containing chlorine such as quaternary ammonium chloride or quaternary ammonium perchlorate. In at least one of the cases, even when stored in a high-temperature and high-humidity environment for a long period of time, the effect of suppressing the occurrence of image quality defects is more exhibited when used in an image forming apparatus.

  In addition to the elastic material, the conductive agent, the conductive elastic layer includes a softener, a plasticizer, a curing agent, a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a filler such as silica and calcium carbonate, as necessary, It may contain materials that can be added to normal rubber. The conductive elastic layer is formed by coating the peripheral surface of the conductive core 14 with a mixture in which a material usually added to rubber is added.

  The surface layer that the charging layer 16 may have is formed for the purpose of preventing contamination by foreign matters, and any material such as resin or rubber may be used as the material for the surface layer. Not what you want. 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 polymer materials such as ethylene vinyl acetate copolymer.

  Of these, polyvinylidene fluoride, a tetrafluoroethylene copolymer, polyester, polyimide, and copolymer nylon are preferably used from the viewpoint of preventing contamination by an external additive. The copolymer nylon includes one or more of 610 nylon, 11 nylon, and 12 nylon as polymerized units, and the other polymer units contained in the copolymer include 6 nylon. 66 nylon and the like. Here, the proportion of polymer units composed of 610 nylon, 11 nylon, and 12 nylon contained in the copolymer is preferably 10% by mass or more in total by mass ratio. When the polymerized unit is 10% by mass or more, it has excellent liquid preparation properties and film formability during coating of the surface layer, and particularly less wear of the resin layer and adhesion of foreign matter to the resin layer during repeated use, and durability of the roll Excellent properties and less change in properties due to the environment.

  The above polymer materials may be used alone or in combination of two or more. Further, the number average molecular weight of the polymer material is preferably in the range of 1,000 or more and 100,000 or less, and more preferably in the range of 10,000 or more and 50,000 or less.

  The surface layer may 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 adjusting the resistance value, at least one of electrons and ions such as carbon black, conductive metal oxide particles, or ionic conductive agent blended in the matrix material is used as a charge carrier. A material in which a material that conducts electricity is dispersed may be used.

  Specifically, carbon black as a conductive agent includes “Special Black 350”, “Special Black 100”, “Special Black 250”, “Special Black 5”, “Special Black 4” manufactured by Degussa, "Special Black 4A", "Special Black 550", "Special Black 6", "Color Black FW200", "Color Black FW2", "Color Black FW2V", "MONARCH1000" manufactured by Cabot, Cabot “MONARCH1300” manufactured by the company, “MONARCH1400” manufactured by Cabot, “MOGUL-L”, “REGAL400R”, and the like.

  The carbon black preferably has a pH of 4.0 or less. Compared to general carbon black, it has good dispersibility in the resin composition due to the effect of oxygen-containing functional groups present on the surface. By adding carbon black with pH 4.0 or lower, charging uniformity is improved. In addition, the fluctuation of the resistance value is further suppressed.

  The conductive metal oxide particles, which are conductive particles for adjusting the resistance value, are conductive materials such as tin oxide, tin oxide doped with antimony, zinc oxide, anatase titanium oxide, and indium tin oxide (ITO). As long as the conductive agent is a conductive agent using electrons as charge carriers, any material may be used, and there is no particular limitation. These may be used alone or in combination of two or more. In addition, any particle size may be used as long as the effect of the present embodiment is not impaired, but from the viewpoint of resistance value adjustment and strength, tin oxide, antimony-doped tin oxide, and anatase-type titanium oxide are preferable. Furthermore, tin oxide and tin oxide doped with antimony are preferred.

  By performing resistance control with such a conductive material, the resistance value of the surface layer does not change depending on environmental conditions, and stable characteristics can be obtained.

  Furthermore, a fluorine-based or silicone-based resin or the like may be used for the surface layer. In particular, it is preferably configured to contain a fluorine-modified acrylate polymer. Moreover, you may add particle | grains in a surface layer. As a result, the surface layer becomes hydrophobic and acts to prevent the foreign matter from adhering to the charging roll 10. Further, insulating particles such as alumina and silica are added to give unevenness to the surface of the charging roll 10, thereby reducing the burden at the time of rubbing against the photosensitive member 24, and the charging roll 10 and the photosensitive member 24 are mutually connected. The wear resistance may be improved.

  The diameter of the charging roll 10 is preferably φ8 mm or more and φ15 mm or less, more preferably φ9 mm or more and φ14 mm or less, and the thickness of the charging layer 16 is preferably 1.5 mm or more and 4 mm or less. When the diameter exceeds 15 mm, the number of times of contact with foreign matter per place on the peripheral surface is reduced, and the number of discharges is reduced. Therefore, although it is excellent in long-term stability against dirt and charging performance, it is disadvantageous from the viewpoint of miniaturization. If the diameter is less than 8 mm, the image forming apparatus and the like are small, which is advantageous. However, since the number of times of contact with foreign matter per peripheral surface increases and the number of discharges increases, it is disadvantageous for long-term stability. Become.

  The conductive member according to the present embodiment includes, for example, an impregnation treatment step of performing an impregnation treatment of the conductive core with methacrylic acid ester or sodium silicate, and a vulcanization molding of a resin-containing composition to form a conductive elastic layer. And a vulcanization molding step to be formed. In the case of a charging roll, a conductive elastic layer may be formed by vulcanizing and molding a resin-containing composition on the surface of the conductive core in the vulcanization molding step.

  The conductive member according to the present embodiment uses a charging member such as a charging roll for charging the surface of the image carrier in the image forming apparatus, and a toner image developed on the surface of the image carrier in the image forming apparatus as a transfer target. Used for transfer members such as transfer rolls for transfer, developing members such as development rolls for developing toner images by developing latent images formed on the surface of an image carrier in an image forming apparatus, and in particular, charging rolls It is suitably used for a charging member such as a transfer member such as a transfer roll.

  Next, the cleaning roll 12 will be described.

  As the material of the core 18 of the cleaning roll 12, free-cutting steel, stainless steel, or the like is used, and the material and surface treatment method are appropriately selected according to applications such as slidability. It may be processed by a general process such as a plating process and subjected to a conductive process, or may be used as it is. Further, since the charging roll 10 is brought into contact with the charging roll 10 with an appropriate nip pressure via the elastic layer 20, a material having a strength that does not bend at the time of nip or a shaft diameter having sufficient rigidity with respect to the shaft length may be selected. preferable.

  The elastic layer 20 includes a foam having a porous three-dimensional structure. Examples of the foam include foamable resins such as polyurethane, polyethylene, polyamide, and polypropylene, nitrile rubber (NBR), ethylene-propylene-diene terpolymer rubber (EPDM), styrene-butadiene rubber (SBR), and silicone. It is selected from those made of rubber or the like. The elastic layer 20 efficiently cleans foreign matters by driven sliding friction with the charging roll 10, and at the same time, the surface of the charging roll 10 is not scratched by rubbing of the elastic layer 20. In order to prevent the occurrence of cracks, at least one of polyurethane, nitrile rubber, ethylene-propylene-diene terpolymer rubber, styrene-butadiene rubber, and silicone rubber, which is resistant to tearing and pulling, is more preferably used. Is particularly preferably used.

  The polyurethane is not particularly limited, and polyols such as polyester polyol, polyether polyester and acrylic polyol, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolidine diisocyanate, It only needs to be accompanied by a reaction of an isocyanate such as 1,6-hexamethylene diisocyanate, and a chain extender such as 1,4-butanediol or trimethylolpropane is preferably mixed. In general, foaming is performed using a foaming agent such as water, azodicarbonamide, azo compounds such as azobisisobutyronitrile. Furthermore, you may add auxiliary agents, such as a foaming aid, a foam stabilizer, a catalyst, as needed.

<Process cartridge>
The process cartridge according to this embodiment includes an image carrier and the conductive member as a charging member that charges the surface of the image carrier. The process cartridge according to the present embodiment includes a charging member cleaning member for cleaning the charging member, a latent image forming unit that forms a latent image on the surface of the charged image holding member, and the surface of the image holding member, as necessary. Developing means for developing the latent image formed on the surface of the toner with toner, a transfer means for transferring the toner image formed on the surface of the image carrier to the transfer target, and the surface of the image carrier after transfer And at least one selected from the group consisting of an image carrier cleaning means for cleaning the image.

  A schematic configuration of an example of the process cartridge according to the embodiment of the present invention is shown in FIG. 3, and the configuration will be described. The process cartridge 3 includes a photosensitive member (electrophotographic photosensitive member) 24 as an image carrier on which an electrostatic latent image is formed, a cylindrical charging roll 10 as a charging member that contacts and charges the surface of the photosensitive member 24, A toner image is formed by attaching toner to a cleaning roll 12 as a charging member cleaning member that contacts the charging roll 10 to clean the surface of the charging roll 10 and an electrostatic latent image formed on the surface of the photoreceptor 24. A developing roll 52 as a developing unit and a cleaning blade 56 as an image carrier cleaning unit that contacts the surface of the photoconductor 24 and cleans toner remaining on the photoconductor 24 after transfer are integrally supported. It is detachable from the image forming apparatus. When mounted on the image forming apparatus, an exposure device 58 as a latent image forming means for forming an electrostatic latent image on the surface of the photosensitive member 24 around the photosensitive member 24 by the charging roll 10, laser light, or reflected light of the document. Further, a developing roll 52, a transfer roll 54 as a transfer means for transferring the toner image on the surface of the photosensitive member 24 to a recording sheet 62 as a transfer target, and a cleaning blade 56 are arranged in this order. For example, the conductive core of the charging roll 10 is impregnated with methacrylic acid ester or sodium silicate. In FIG. 3, functional units normally required in other electrophotographic processes are omitted.

  The operation of the process cartridge 3 according to this embodiment will be described.

  First, the surface of the photoconductor 24 is charged to a high potential by supplying a voltage from a high voltage power source (not shown) to the charging roll 10 in contact with the surface of the photoconductor 24. At this time, the photosensitive member 24 and the charging roll 10 rotate in the directions of the arrows in FIG. After charging, when image light (exposure) 60 corresponding to image information is irradiated onto the surface of the photoconductor 24 by the exposure device 58, the potential of the irradiated portion decreases. Since the image light 60 has a light amount distribution corresponding to the black / white of the image, a potential distribution corresponding to the recorded image, that is, an electrostatic latent image is formed on the surface of the photosensitive member 24 by irradiation of the image light 60. When the portion where the electrostatic latent image is formed passes through the developing roll 52, toner adheres according to the level of the potential, and a toner image in which the electrostatic latent image is visualized is formed. The recording paper 62 is conveyed to the portion where the toner image is formed by a resist roll (not shown) at a predetermined timing, and overlaps the toner image on the surface of the photoreceptor 24. After the toner image is transferred to the recording paper 62 by the transfer roll 54, the recording paper 62 is separated from the photoreceptor 24. The separated recording paper 62 is transported through a transport path, fixed by heating and pressure by a fixing unit (not shown) as fixing means, and then discharged outside the apparatus.

  The charging roll 10 provided in the process cartridge 3 is provided with a cleaning roll 12, a voltage is applied to the bearing 28 from a high-voltage power source, and the cleaning roll 12 has the same polarity as the charging roll 10, so that foreign matter is removed. Since it moves with little accumulation on the surfaces of the cleaning roll 12 and the charging roll 10 and is collected by the cleaning blade 56, foreign matters such as toner adhering to the charging member are stably removed over a long period of time. For this reason, a stable charging performance is maintained with little accumulation of dirt on the charging roll 10 over a long period of time.

  The photoreceptor 24 has a function of forming at least an electrostatic latent image (electrostatic charge image). In the electrophotographic photosensitive member, an undercoat layer, a charge generation layer containing a charge generation material, and a charge transport layer containing a charge transport material are formed in this order on the outer peripheral surface of a cylindrical conductive substrate as necessary. It is a thing. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. Further, a protective layer may be provided on the photosensitive layer. Further, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used without being limited to the organic photoreceptor.

  The exposure device 58 is not particularly limited. For example, a laser optical system that exposes a light source such as semiconductor laser light, LED light, or liquid crystal shutter light on the surface of the photoconductor 24 in a desired image-like manner, or an optical such as an LED array. System equipment.

  The developing unit has a function of forming a toner image by developing the electrostatic latent image formed on the photosensitive member 24 with a one-component developer or a two-component developer containing an electrostatic charge image developing toner. Such a developing device is not particularly limited as long as it has the above-described functions, and may be appropriately selected according to the purpose. Even a system in which the toner layer is in contact with the photoreceptor 24, a system in which the toner layer is not in contact It may be a thing. For example, as shown in FIG. 3, a developing device having a function of attaching toner for developing an electrostatic image to the photosensitive member 24 using the developing roll 52, or developing having a function of attaching the toner to the photosensitive member 24 using a brush or the like. And a known developing device.

  The transfer unit may be a type that directly transfers to paper or the like, or a type that transfers via an intermediate transfer member. For example, a transfer roll 54 and a transfer roll pressing device (not shown) using a conductive or semiconductive roll that directly transfers through a recording sheet 62 as shown in FIG. 3 may be used. Further, a recording sheet 62 may be used in which a charge having a polarity opposite to that of the toner is applied to the recording sheet 62 from the back side (the side opposite to the photoreceptor) of the recording sheet 62 and the toner image is transferred to the recording sheet 62 by electrostatic force. The transfer roll 54 may be arbitrarily set depending on the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is preferably used as the transfer roll 54 for cost reduction. The conductive core of the transfer roll 54 may be impregnated with methacrylic acid ester or sodium silicate.

  The fixing unit as the fixing unit is not particularly limited as long as the toner image transferred onto the recording paper 62 is fixed by heating, pressing, or heating and pressing.

  Examples of the recording paper 62 that is a transfer target to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer material is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Preferably used.

<Image forming apparatus>
The image forming apparatus according to the present embodiment includes an image carrier, the conductive member as a charging member that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and an image. Developing means for developing the latent image formed on the surface of the holding body with toner to form a toner image. The image forming apparatus according to the present embodiment includes, as necessary, a charging member cleaning member for cleaning the charging member, a transfer unit that transfers a toner image formed on the surface of the image carrier to the transfer target, and a transfer You may provide at least 1 type selected from the group which consists of an image holding body cleaning means which cleans the surface of a subsequent image holding body. The image forming apparatus according to the present embodiment may use the process cartridge.

  FIG. 4 shows a schematic configuration of an example of the image forming apparatus according to the present embodiment, and the configuration will be described. The image forming apparatus 5 includes a photosensitive member 24 as an image carrier on which an electrostatic latent image is formed, a cylindrical charging roller 10 as a charging member that contacts and charges the surface of the photosensitive member 24, and a contact with the charging roller 10. Then, a cleaning roll 12 as a charging member cleaning member for cleaning the surface of the charging roll 10 and exposure as a latent image forming means for forming an electrostatic latent image on the surface of the photosensitive member 24 by laser light or reflected light of a document. The apparatus 58, a developing roll 52 as a developing unit for forming a toner image by attaching toner to the electrostatic latent image formed on the surface of the photosensitive member 24, and the toner image on the surface of the photosensitive member 24 being a transfer target. A transfer roll 54 as a transfer means for transferring to the recording paper 62 and a cleaner as an image carrier cleaning means for contacting the surface of the photoconductor 24 and cleaning the toner remaining on the photoconductor 24 after transfer. And a ring blade 56. In the image forming apparatus 5, the charging roll 10, the exposure device 58, the developing roll 52, the transfer roll 54, and the cleaning blade 56 are arranged in this order around the photoreceptor 24. For example, the conductive core of the charging roll 10 is impregnated with methacrylic acid ester or sodium silicate. In FIG. 4, description of functional units normally required in other electrophotographic processes is omitted. Each configuration of the image forming apparatus 5 and operations during image formation are the same as those of the process cartridge 3 of FIG.

  The charging roll 10 provided in the image forming apparatus 5 is provided with a cleaning roll 12, a voltage is applied to the bearing 28 from the high voltage power source 64, and the cleaning roll 12 has the same polarity as the charging roll 10, The foreign matter moves without accumulating on the surfaces of the cleaning roll 12 and the charging roll 10 and is collected by the cleaning blade 56. Therefore, the foreign matter such as toner adhering to the charging member is stably removed over a long period of time. As a result, the charging roll 10 does not accumulate dirt over a long period of time and is excellent in uniform charging performance, and stable charging performance is maintained.

  The configuration other than the charging member of the image forming apparatus using the charging member according to the present embodiment is not limited thereto, and conventionally known configurations may be applied as the respective configurations of the electrophotographic image forming apparatus. That is, the configuration other than the charging member, for example, a charging member cleaning unit, a latent image forming unit, a developing unit, a transfer unit, an image carrier cleaning unit, a charge eliminating unit, a sheet feeding unit, a conveying unit, an image control unit, etc. According to the above, conventionally known ones are appropriately employed. These configurations are not particularly limited in the present embodiment.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

<Example 1>
(Preparation of conductive roll)
[Preparation of conductive core]
As the conductive core, a cylindrical rod made of a SUM material having a diameter of 8 mm was cut into a length of 330 mm and subjected to electroless nickel plating with a thickness of 6 μm. This conductive core was evacuated for 10 minutes in a vacuum state of 0.7 kPa or less using an impregnation apparatus BS-200A manufactured by Chuo Inventive Laboratories Co., Ltd. P-601, Central Research Laboratory, Inc.) was immersed and pressurized at 0.5 MPa for 5 minutes, washed with water, and then immersed in water at 90 ° C. for 10 minutes for impregnation treatment. The hot water was drained at 100 rpm for 5 minutes with a centrifuge and cooled to room temperature (22 ° C.).

[Formation of conductive elastic layer]
After kneading the compound shown in Table 1 using a tangential pressure kneader (manufactured by Moriyama Co., Ltd .: actual capacity 75 L), kneading into a sheet shape in a 22 mm open roll, and obtaining a rubber kneaded material, Using an uniaxial rubber extruder with a cylinder inner diameter of 60 mm and L / D20, the unvulcanized rubber material of the above compound is extruded at a screw rotation of 15 rpm, and at the same time, the conductive core subjected to the impregnation treatment is continuously crossed. By passing the head (die inner diameter φ12 mm, nipple diameter φ8 mm), the unvulcanized rubber was coated on the conductive core. The temperature conditions of the extruder were set to 80 ° C. for all of the cylinder part, screw part, head part, and die part. After extrusion, normal pressure vulcanization was performed in an oven at 180 ° C. for 30 minutes to obtain a conductive roll.

  The conductive core of the conductive roll has a cured product of methacrylic acid ester in the hole. The impregnated surface is 500 to 1,000 times using a digital microscope (VHX-500, manufactured by Keyence Corporation). It was confirmed by the method of observing.

(Evaluation of conductive roll)
A conductive roll at room temperature (22 ° C.) was placed in a high-temperature and high-humidity tank at 45 ° C. and 95% RH, and stored for one month from the state of condensation. Thereafter, the conductive roll was taken out and left at room temperature (22 ° C.) for 12 hours, and then the surface thereof was visually observed to evaluate the swelling of rubber according to the following criteria. Further, after the blistering evaluation, the rubber was peeled off from the conductive core, and the corrosion state of the conductive core was also observed visually. Corrosion was evaluated based on the following criteria with reference to the rating number (RN) value in the rating number method of JIS Z2371 (2000) Annex 1. The results are shown in Table 2.

[Rubber of rubber]
◎: No rubber bulge ○: Extremely slight blisters 2 or less ×: 2 or more blisters [corrosion of conductive core]
The rating number (RN) was evaluated according to the following criteria. The results are shown in Table 2.
A: 9.5 or more B: Less than 9.5 9.0 or more X: Less than 9.0

[Image quality evaluation]
The charging roll produced by the above method is mounted on a copier Apeos Port-IV C5570 (Fuji Xerox Co., Ltd.), and 50,000 sheets of A4 printing test (25,000 sheets under 28 ° C. and 85% RH environment) Thereafter, 25,000 sheets were printed in an environment of 10 ° C. and 15% RH. If a major problem occurred during the process, printing was stopped at that time. The image quality evaluation was performed on the basis of the following criteria based on the presence or absence of density unevenness in the 10% halftone image with respect to the initial image and the image after running 50,000 sheets. The results are shown in Table 2.
◎: No defect such as density unevenness ○: Very slight density unevenness △: Minor density unevenness ×: Concentration unevenness that cannot be used

<Example 2>
A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 3>
A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 4>
A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 5>
A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 6>
Other than impregnating the conductive core using a blend of 2-ethylhexyl methacrylate 65% by mass, ethylene glycol dimethacrylate 34% by mass, benzoyl peroxide 0.8% by mass, hydroquinone 0.2% by mass as an impregnating agent. Were obtained in the same manner as in Example 2 and evaluated. The results are shown in Table 2.

<Example 7>
The impregnation treatment was performed in the same manner as in Example 1 except that the SUM material subjected to chrome plating was used. A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 8>
The impregnation treatment was performed in the same manner as in Example 1 except that SUS304 that was not plated was used as the conductive core. A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 9>
The impregnation treatment was performed in the same manner as in Example 1 except that an aluminum core that was not plated was used as the conductive core. A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Example 10>
The same conductive core as in Example 1 was evacuated for 15 minutes in a vacuum state of 2.7 kPa using an impregnation apparatus BS-200A manufactured by Central Research Institute, Inc., and sodium silicate (Na ₂ SiO ₃ , product) Name: Technicyal BP-3, Central Research Laboratory, Inc.), soaked and pressurized at 0.5 MPa for 15 minutes, washed with water, then cured with hot air at 80 ° C. for 60 minutes for impregnation treatment did. Then, it cooled to normal temperature. A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The conductive core of the conductive roll has a cured product of sodium silicate in the hole. The impregnated surface is 500 to 1,000 times using a digital microscope (VHX-500, manufactured by Keyence Corporation). This was confirmed by the observation method. The results are shown in Table 2.

<Example 11>
A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Comparative Example 1>
As the conductive core, a cylindrical rod made of an SUM material having a diameter of 8 mm used in Example 1 was cut into a length of 330 mm and subjected to electroless nickel plating with a thickness of 6 μm, and the impregnation treatment was not performed. . Conductive rolls were obtained in the same manner as in Example 1 and evaluated. The results are shown in Table 2.

<Comparative Example 2>
A conductive roll was obtained and evaluated in the same manner as in Comparative Example 1 except that the conductive elastic layer was formed using the composition shown in Table 1. The results are shown in Table 2.

<Comparative Example 3>
As the conductive core, the SUM-plated SUM material used in Example 7 was used, and the impregnation treatment was not performed. A conductive roll was obtained and evaluated in the same manner as in Example 1 except that the conductive elastic layer was formed using the formulation shown in Table 1. The results are shown in Table 2.

<Comparative Example 4>
The same conductive core as that of Example 1 was used as an impregnating agent under the conditions of Example 1 by using an epoxy resin (manufactured by Nippon Rika Co., Ltd., Rica Resin HBE-100 (4,4′-isopropylidenedicyclohexanol and (chloromethyl) oxirane). Polymer)) was used to perform the impregnation treatment, but the flowability of the impregnating agent containing the epoxy resin was poor, and after the series of impregnation treatment, a digital microscope (manufactured by Keyence Corporation, VHX-500) was used. When the impregnated surface was observed at 1,000 times, it was confirmed that the defect portion of the plated portion was not well filled with the impregnating agent. A conductive roll was obtained and evaluated in the same manner as in Comparative Example 2 except that this impregnation treatment was performed. The results are shown in Table 2.

<Comparative Example 5>
The same conductive core as in Example 1 was impregnated under the conditions of Example 1 using a colloidal silica alumina based inorganic colloidal sol impregnating agent as the impregnating agent. However, the colloidal silica alumina based inorganic colloidal sol impregnating agent has a large volumetric shrinkage during the curing reaction and poor adhesion to the plating layer material, and 500- using a digital microscope (manufactured by Keyence Corporation, VHX-500). When the impregnated surface was observed at 1,000 times, it was confirmed that the impregnating agent filled in the defective portion of the plated portion had cracks or defects. A conductive roll was obtained and evaluated in the same manner as in Example 2 except that this impregnation treatment was performed. The results are shown in Table 2.

  In Table 1, epichromer CG102 is epichlorohydrin rubber, NBR230S is acrylonitrile-butadiene copolymer rubber, Kachigen BC-50 is lauryldimethylbenzylammonium chloride, and LXN-30 is lauryltrimethylammonium perchlorate.

  As shown in Table 2, by using the conductive rolls of Examples 1 to 11, compared to the case of using the conductive rolls of Comparative Examples 1 to 5, the conductive roll was kept in a high temperature and high humidity environment for a long time. Even when stored in an image forming apparatus, the occurrence of image quality defects was suppressed when used in an image forming apparatus. Further, in the conductive rolls of Examples 1 to 11, compared with the conductive rolls of Comparative Examples 1 to 5, rubber swelling and corrosion of the conductive core when stored in a high temperature and high humidity environment for a long time are suppressed. It was done.

  DESCRIPTION OF SYMBOLS 1 Charging apparatus, 3 Process cartridge, 5 Image forming apparatus, 10 Charging roll, 12 Cleaning roll, 14 Conductive core body, 16 Charging layer, 18 core body, 20 Elastic layer, 24 Photosensitive body, 26 Coil spring, 28 Bearing, 52 Developing roll, 54 Transfer roll, 56 Cleaning blade, 58 Exposure device, 60 Image light, 62 Recording paper, 64 High voltage power supply.

Claims (7)

A conductive core having a hole on the surface, and a conductive elastic layer formed on the conductive core;
The conductive core may have a methacrylic acid ester or a cured product of the sodium silicate in the hole,
The conductive member, wherein the methacrylic acid ester is an alkyl, alkene or alkyne methacrylic acid ester having 1 to 30 carbon atoms .   The conductive member according to claim 1, wherein the conductive elastic layer contains a resin containing chlorine.   The conductive member according to claim 1, wherein the conductive elastic layer contains a conductive agent containing chlorine.   The conductive member is a charging member that charges the surface of the image carrier in the image forming apparatus or a transfer member that transfers the developed toner image on the surface of the image carrier in the image forming apparatus to a transfer target. The conductive member according to claim 1, wherein the conductive member is characterized in that   A charging device comprising the conductive member according to claim 1.   A process cartridge comprising: an image carrier; and the conductive member according to claim 1 that charges a surface of the image carrier.   An image carrier, a conductive member according to any one of claims 1 to 3 that charges a surface of the image carrier, and a latent image forming unit that forms a latent image on the surface of the image carrier; An image forming apparatus comprising: a developing unit that develops a latent image formed on the surface of the image carrier with toner to form a toner image.

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