JP2010204188A - Charging roll, charging device, and process cartridge and image forming apparatus provided with charging roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging roll and a charging device, which have good electrostatic chargeability and little change in shape and electrical properties due to aging and suppress the occurrence of harmful substances particularly even when used and stored under high temperatures and high humidities; and to provide a process cartridge and an image forming apparatus provided with the charging roll. <P>SOLUTION: The charging roll is in contact with a body to be charged while voltage is applied and electrifies the body to be charged. An adhesive layer 32, an elastic layer34, and a surface layer36 are formed sequentially on an outer periphery of an electroconductive support 31. The adhesive layer 32 contains a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  An image forming apparatus using an electrophotographic method forms a uniform charge on an image carrier (photosensitive member), forms an electrostatic latent image with a laser or the like that modulates an image signal, and then uses the charged toner to The electrostatic latent image is developed into a toner image. Then, a desired transfer image can be obtained by electrostatically transferring the toner image to the recording material medium via an intermediate transfer member.

  In an image forming apparatus using an electrophotographic system, in a charging device, a corona discharge or a scorotron that is charged by a corona discharge generated by applying a high voltage to a conventional metal wire is changed, and generally a voltage to be applied is small. A charging roll with a small amount of generation is widely used.

  The charging roll is a roll shape in which at least an elastic layer made of rubber or elastomer is formed on a conductive support made of a metal or alloy such as stainless steel; and iron plated with chromium or nickel. In addition, a resistance layer and a surface layer are formed on the elastic layer as necessary. The charging roll is often used to contact and energize to uniformly charge the surface of the object to be charged or to form a uniform electric field. It is necessary to form a uniform nip and an elastic layer is formed. .

  A charging roll having an elastic layer formed on a conductive support is made of a metal or an alloy such as stainless steel; a conductive support made of iron plated with chromium, nickel, etc. A configured elastic layer is formed.

  Between the conductive support and the elastic layer, during the vulcanization of the elastic layer, unnecessary adhesion or discoloration occurs between the conductive support and the elastic layer due to the seizure of rubber to the conductive support by a chemical reaction. The elastic layer compound material corrodes the conductive support during long-term storage under high temperature and high humidity.

  Patent Document 1 describes that the surface of a conductive support is subjected to an inactivation treatment. However, when the conductive support is corroded, deformation or the like occurs in the corroded portion, and the electrical characteristics change and become uneven. May occur.

  Since uniformity of resistance is required for uniform charging and formation of a uniform electric field, an epichlorohydrin-ethylene oxide rubber having a low resistance of the rubber itself is often used for the elastic layer. However, the elastic layer compound material tends to corrode the conductive support during long-term storage under high temperature and high humidity.

  In Patent Document 2, in the conductive rubber roller having a rubber layer containing epichlorohydrin rubber on the outer periphery of an electroless nickel-plated conductive cored bar through an adhesive layer, the adhesive layer Includes a phenolic resin and acrylonitrile butadiene rubber, the adhesive layer includes 1 to 10 wt% of acrylonitrile butadiene rubber, and the acrylonitrile butadiene rubber includes 25 to 60 wt% of an acrylonitrile component. Yes.

  In Patent Document 3, a conductive elastic layer having a rubber containing a halogen atom is provided on the outer periphery of a conductive support shaft via a conductive adhesive layer, and the conductive adhesive layer is made of a phenol resin. , Having an epoxy resin and a conductive agent, having a phenol resin content of 40 mass% to 70 mass%, an epoxy resin content of 10 mass% to 50 mass%, and a conductive agent content of 10 mass%. Further, it is described that the conductive adhesive layer contains a synthetic rubber selected from acrylonitrile-butadiene rubber (NBR), acrylic rubber and urethane rubber.

Japanese Patent Publication No. 7-74056 JP 2006-195159 A JP 2006-208447 A

  In particular, the present invention provides a charging roll, a charging roller that has good chargeability and little change with time in shape and electrical characteristics and suppresses the generation of harmful substances even when used or stored under high temperature and high humidity. It is an object of the present invention to provide an apparatus, a process cartridge provided with a charging roll, and an image forming apparatus.

  The above-mentioned subject is achieved by the following present invention. That is, the charging device, the process cartridge including the charging roll, and the image forming apparatus of the present invention have the following characteristics.

  (1) A charging roll that contacts a member to be charged in a state where a voltage is applied and charges the member to be charged, and the charging roll has at least an adhesive layer and an elastic layer sequentially formed on a conductive support, The adhesive layer is a charging roll containing a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber.

  (2) A charging roll that contacts a member to be charged in a state where a voltage is applied and charges the member to be charged, and the charging roll has at least two or more adhesive layers and an elastic layer on the conductive support. Are sequentially formed, and the adhesive layer that adheres to the elastic layer is a charging roll containing a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber.

  (3) The adhesive roll that adheres to the conductive support is the charging roll according to (2), which is made of a polyolefin-based adhesive.

  (4) The adhesive roll that adheres to the conductive support is the charging roll according to the above (2), which is made of a chlorine rubber adhesive.

  (5) The charging roll according to any one of (1) to (4), wherein the conductive support is subjected to a trivalent chromium electroless nickel plating treatment.

  (6) A process cartridge including at least the charging roll according to any one of (1) to (5) above.

  (7) An image forming apparatus including at least an image carrier and a charging unit that contacts the image carrier and charges the surface thereof, wherein the charging unit is any one of (1) to (5). An image forming apparatus comprising the charging roll described in 1 above.

  According to the first aspect of the present invention, the adhesion between the conductive support and the elastic layer is stronger than before, the storage stability under high temperature and high humidity is also improved, and the shape and electrical characteristics over time are improved. There is little change and the generation of harmful substances is prevented.

  According to the invention described in claim 2 of the present application, the adhesion between the conductive support and the elastic layer becomes stronger than before, the storage stability of the charging roll under high temperature and high humidity is improved as compared with the conventional, There is little change in characteristics over time, and generation of harmful substances is prevented.

  According to the invention described in claim 3, in the adhesive layer of two or more layers, the adhesion between the conductive support and the other adhesive is stronger than before, and the storage stability of the charging roll under high temperature and high humidity is also improved. Compared to conventional methods, the shape and electrical characteristics are less changed with time, and the generation of harmful substances is prevented.

  According to the invention described in claim 4, in the adhesive layer of two or more layers, the adhesion between the conductive support and the other adhesive is considerably stronger than before, and the storage stability of the charging roll under high temperature and high humidity. In comparison with the prior art, there is little change in shape and electrical characteristics over time, and generation of harmful substances is prevented.

  According to the invention described in claim 5, the corrosion is suppressed, the adhesion between the conductive support and the elastic layer becomes stronger than before, and the storage stability of the charging roll under high temperature and high humidity is also improved compared to the conventional. The shape and electrical characteristics change little over time, and the generation of harmful substances is prevented.

  According to the invention described in claim 6, the durability and the environment dependency are improved as compared with the conventional case.

  According to the seventh aspect of the present invention, durability and environmental dependency are improved as compared with the prior art.

It is sectional drawing along the diameter which shows an example of a structure of the charging roll in this invention. It is sectional drawing along the diameter which shows the other example of a structure of the charging roll in this invention. It is sectional drawing along the diameter which shows the other example of a structure of the charging roll in this invention. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus according to the present invention. It is a schematic sectional drawing which shows the other example of the image forming apparatus in this invention. It is a schematic sectional drawing which shows the other example of the image forming apparatus in this invention.

  Embodiments of the present invention will be described below. In describing the embodiment of the present invention in detail, the charging roll in this embodiment will be described in detail first, and then the charging device, process cartridge, and image forming apparatus provided with the charging roll in this embodiment will be described. State. In addition, the charging roll of this Embodiment is not restricted to a charging roll, Other forms are accept | permitted. Also, the dimensions of each component in the drawing may differ from the actual dimensions.

<Charging roll>
FIG. 1 is an example of a charging roll in the present embodiment, and shows a cross-sectional view along the radial direction of the charging roll. As shown in FIG. 1, the charging roll in the present embodiment is a charging roll that comes into contact with an object to be charged in a state where a voltage is applied and charges the object to be charged, and is bonded to the outer periphery of the conductive support 31. A layer 32, an elastic layer 34, and a surface layer 36 are sequentially formed.

  FIG. 2 shows a schematic configuration of another charging roll in the present embodiment. As shown in FIG. 2, another charging roll of the present embodiment is a charging roll that contacts a member to be charged in a state where a voltage is applied and charges the member to be charged. In addition, an adhesive layer 32, an elastic layer 34, an intermediate layer 35 containing no filler, and a surface layer 36 are sequentially formed.

  Further, as shown in FIG. 3, the other charging roll in the present embodiment is a charging roll that contacts the member to be charged in a state where a voltage is applied and charges the member to be charged. A first adhesive layer 33, a second adhesive layer 32, an elastic layer 34, and a surface layer 36 are sequentially formed on the outer periphery of the substrate.

  Next, each configuration of each charging roll described above in the present embodiment will be specifically described below.

  The conductive support 31 functions as an electrode and a support member of the charging roll. For example, a metal or an alloy such as aluminum, copper alloy, or stainless steel; iron that has been plated with chromium, nickel, or the like; It is made of a conductive material such as resin.

  The adhesive layer 32 and the second adhesive layer 32 are adhesive layers that adhere to the elastic layer 34, and contain a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber (hereinafter also referred to as “NBR”). The acrylonitrile-butadiene rubber contained in the adhesive layer 32 and the second adhesive layer 32 is not particularly limited, but is used in a state of being dissolved in a solvent such as toluene or in a liquid NBR in order to be contained in the adhesive.

  The acrylonitrile content in the acrylonitrile-butadiene copolymer rubber is preferably medium nitrile to medium-high nitrile. For example, the acrylonitrile content is preferably 25% by mass or more and less than 36% by mass with respect to 100 parts by mass of NBR. When the amount of acrylonitrile is low, the blocking property of the elastic layer composition is not sufficient, and when the amount of acrylonitrile is high, the elasticity is lowered, the temperature change and the shape at the elastic layer interface cannot be followed, and the adhesiveness is lowered.

  Further, NBR may contain a functional group such as a carboxyl group, and NBR containing a carboxyl group has improved adhesiveness as compared with those not containing a carboxyl group or the like. In particular, in NBR containing a carboxyl group, the carboxyl group is preferably 0.05% by mass or more and 10% by mass or less with respect to 100 parts by mass of NBR.

  The amount of NBR added to the adhesive forming the adhesive layer 32 and the second adhesive layer 32 is preferably 15 parts by mass or more and 50 parts by mass or less, and 20 parts by mass or more and 40 parts by mass with respect to 100 parts by mass of the adhesive. The following is more preferable. If the adhesive layer 32 and the second adhesive layer 32 contain NBR within the above range, (A) even if microscopic corrosion occurs on the surface of the conductive support 31, it is compared with the adhesive alone. As a result, the film thickness of the adhesive layer 32 is increased, so that an image comparable to the case where no corrosion occurs on the surface of the conductive support 31 is formed, and (B) leveling at the time of forming the adhesive layer 32 is improved. The contact frequency with the adhesive surface of the elastic layer 34 having irregularities is improved, and (C) the elastic layer 34 is vulcanized even at the interface between the elastic layer 34 and the NBR in the adhesive layer 32 during vulcanization, The adhesion between the elastic layer 34 and the adhesive layer 32 is stronger than the adhesive layer not containing NBR (adhesive strength to the extent that the elastic layer breaks if it is forcibly removed). As a result, the conductive support 31 and Bonding with the elastic layer 34 and bonding between the first bonding layer 33 and the elastic layer 34 are strong. It becomes, but also trouble occurs in storage at high temperature and high humidity is suppressed.

  Further, in the adhesive layer 32 and the second adhesive layer 32, the polyolefin adhesive mixed with NBR has high adhesiveness to the elastic layer 34, particularly adhesiveness to the halogen rubber, and the polyolefin adhesive. May contain methylene-bis (4,1-phenylene) = diisocyanate.

  As shown in FIG. 3, when two or more adhesive layers are formed, the adhesive layer 32 and the second adhesive layer 32 that adhere to the elastic layer 34 are made of a polyolefin-based adhesive and NBR as described above. Other adhesive layers (including the first adhesive layer 33 shown in FIG. 3) are not particularly limited as long as they are contained, but polyolefin-based, chlorinated rubber, acrylic-based, epoxy-based, polyurethane-based, nitrile Rubber-based, vinyl chloride-based, vinyl acetate-based, polyester-based, phenol-based, and silicone-based adhesives are used, and polyolefin-based, chlorinated rubber-based, and phenol-based adhesives are particularly preferable.

  When forming a plurality of adhesive layers, the adhesive layer other than the adhesive layer 32 (FIGS. 1 and 2) or the second adhesive layer 32 (FIG. 3) that adheres to the elastic layer 34 may not contain NBR. The first adhesive layer 33 (FIG. 3) that adheres to the conductive support 31 is made of a polyolefin-based adhesive or a chlorine rubber-based adhesive and does not contain NBR.

  For the adhesive forming the adhesive layer including the adhesive layer 32, the second adhesive layer 32, and the first adhesive layer 33, carbon black such as ketjen black and acetylene black for imparting conductivity; pyrolytic carbon, Graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; various conductive metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution; Conductive powder such as a conductive surface of an insulating material may be added. The conductive powder added to the adhesive layer is 0 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the adhesive layer, and if it exceeds 5 parts by mass, the hygroscopicity increases and the adhesiveness decreases. .

  The thickness of the adhesive layer including the adhesive layer 32, the second adhesive layer 32, and the first adhesive layer 33 is not particularly limited, but is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. If the film thickness is too thin, sufficient adhesion cannot be obtained, and if it is too thick, cracks occur in the adhesive layer, and a sufficient effect cannot be obtained. The adhesive layer is preferably formed by applying rubber or resin dissolved in a solvent such as a solvent on a conductive support. If necessary, heat treatment may be performed after applying the adhesive.

  The elastic layer 34 is formed of various rubbers or elastomers. Rubber and elastomer materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin- Examples include ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and blended rubbers thereof. Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR and blended rubbers thereof are preferably used. The elastic layer constituent material may be used as a resistance layer material when a resistance layer is formed.

  The elastic layer 34 has conductivity or semi-conductivity, and is generally obtained by dispersing a conductive agent in the resin material or rubber material.

  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.

  These conductive agents may be used alone or in combination of two or more. The amount of addition is not particularly limited, but in the case of the electronic conductive agent, the amount is preferably in the range of 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber material. More preferably, it is in the range of 25 parts by mass or less. On the other hand, in the case of the ionic conductive agent, it is preferably in a range of 0.1 parts by mass or more and 5.0 parts by mass or less, and 0.5 parts by mass or more, 3.0 parts by mass with respect to 100 parts by mass of the rubber material. More preferably, it is in the range of less than or equal to parts by mass.

  The polymer material constituting the surface layer 36 is not particularly limited, but is polyamide, polyurethane, polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, polyimide, silicone resin, acrylic resin, polyvinyl butyral, ethylene tetrafluoroethylene. Examples thereof include copolymers, melamine resins, fluororubbers, epoxy resins, polycarbonates, polyvinyl alcohol, cellulose, polyvinylidene chloride, polyvinyl chloride, polyethylene, and ethylene vinyl acetate copolymers.

  The above polymer materials may be used alone or in combination of two or more. 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 36 is formed as a composition by mixing the polymer material with the conductive agent used in the elastic layer as the conductive agent and various fine particles. Although there is no restriction | limiting in particular in the addition amount, It is preferable that it is the range of 1 to 50 mass parts with respect to 100 mass parts of polymeric materials, and is the range of 5 to 20 mass parts. It is more preferable.

  As the fine particles, metal oxides such as silicon oxide, aluminum oxide, barium titanate and complex metal oxides, and polymer fine powders such as tetrafluoroethylene and vinylidene fluoride are used alone or in combination. Not limited to

  The intermediate layer 35 is obtained by dispersing a conductive agent in a polymer material that does not contain the fine particles and controlling the resistance in order to obtain effects such as tack prevention and bleeding prevention. The thickness of the intermediate layer 35 is, for example, 0.01 μm or more and 1,000 μm or less, preferably 0.1 μm or more and 500 μm or less, and more preferably 0.5 μm or more and 100 μm or less. The polymer material and conductive agent used for the intermediate layer 35 can be the same as the polymer material and conductive agent used for the surface layer 36 described above. The illustration here is omitted.

<Image forming apparatus>
Next, the image forming apparatus according to the present embodiment will be described in detail with reference to FIGS.

  FIG. 4 is a cross-sectional view schematically showing the basic configuration of the image forming apparatus according to the first embodiment of the present invention. An image forming apparatus 200 illustrated in FIG. 4 includes an electrophotographic photosensitive member 207, a charging device 208 that charges the electrophotographic photosensitive member 207, a power source 209 connected to the charging device 208, and an electrophotographic image that is charged by the charging device 208. An exposure device 206 that exposes the photosensitive member 207 to form a latent image, a developing device 211 that develops the latent image formed by the exposure device 206 with toner and forms a toner image, and a toner that is formed by the developing device 211 The image forming apparatus includes a transfer device 212 that transfers an image to an object to be transferred (image output medium) 500, a cleaning device 213, a static eliminator 214, and a fixing device 215. In this case, the static eliminator 214 may not be provided.

  A charging device 208 in FIG. 4 is of a type (contact charging type) in which a conductive member (charging roll) is brought into contact with the surface of the electrophotographic photosensitive member 207 to charge the surface of the photosensitive member 207 (contact charging method). A charging device provided with the charging roll of the present embodiment is used.

  As the exposure device 206, an optical system device that can expose a light source such as a semiconductor laser, an LED (light emitting diode), and a liquid crystal shutter on the surface of the electrophotographic photosensitive member in a desired image-like manner can be used.

  The toner used in this exemplary embodiment includes, for example, a binder resin and a colorant. Examples of the binder resin include homopolymers and copolymers such as styrenes, monoolefins, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, vinyl ethers, and vinyl ketones. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can also be mentioned.

  Colorants include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The toner may be internally added or externally added with a known additive such as a charge control agent, a release agent, or other inorganic fine particles.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but charge control agents such as azo-based metal complex compounds, metal complex compounds of salicylic acid, and resin types containing polar groups can be used.

  As other inorganic fine particles, small-diameter inorganic fine particles having an average primary particle size of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger diameters are used to reduce adhesion. Inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used.

  In addition, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  As a method for producing the toner used in this exemplary embodiment, a polymerization method such as an emulsion polymerization aggregation method or a dissolution suspension method is preferably used because high shape controllability can be obtained. In addition, a manufacturing method may be performed in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure. When an external additive is added, it can be produced by mixing the toner and the external additive with a Henschel mixer or a V blender. Further, when the toner is manufactured by a wet method, it can be externally added by a wet method.

  The transfer device 212 is capable of supplying a current having a predetermined current density toward the electrophotographic photosensitive member when the toner image formed on the electrophotographic photosensitive member 207 is transferred to the transfer target member 500. Is preferred.

  The cleaning device 213 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this is repeatedly used for the image forming process described above. . As the cleaning device, brush cleaning, roll cleaning, and the like can be used in addition to the cleaning blade. Among these, it is preferable to use the cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The image forming apparatus according to the present embodiment may further include an erase light irradiation device 214 as shown in FIG. As a result, when the electrophotographic photosensitive member is repeatedly used, the phenomenon that the residual potential of the electrophotographic photosensitive member is brought into the next cycle is prevented, so that the image quality can be further improved.

  FIG. 5 is a schematic sectional view schematically showing a basic configuration of an image forming apparatus according to the second embodiment of the present invention. The image forming apparatus 210 shown in FIG. 5 transfers the toner image formed on the electrophotographic photosensitive member 207 to the primary transfer member 212a and then supplies it between the primary transfer member 212a and the secondary transfer member 212b. A transfer device of an intermediate transfer system for transferring to a transfer target (image output medium) 500 to be transferred, and at the time of such transfer, a current having a predetermined current density from the primary transfer member 212a toward the electrophotographic photosensitive member. Can be supplied. Although not shown in FIG. 5, the image forming apparatus 210 may further include a static eliminator as in the image forming apparatus 200 shown in FIG. The other configuration of the image forming apparatus 210 is the same as that of the image forming apparatus 200, and a description thereof is omitted here.

  As described above, the image forming apparatus 210 is different in that the intermediate transfer method is applied. However, as in the case of the image forming apparatus 200 according to the first embodiment, the electrophotographic photoreceptor 207 and the present invention. In combination with the charging device, good image quality can be stably obtained over a long period of time.

  Further, when the toner image formed on the electrophotographic photosensitive member 207 is transferred to the primary transfer member 212a, a current having a predetermined current density is supplied from the primary transfer member 212a to the electrophotographic photosensitive member 207. Thus, fluctuations in the transfer current due to the type and material of the transfer medium 500 can be suppressed, so that the amount of charge flowing into the electrophotographic photoreceptor 207 can be accurately controlled. As a result, it is possible to achieve higher image quality and reduced environmental burden at a higher level.

  FIG. 6 is a schematic sectional view schematically showing a basic configuration of an image forming apparatus according to the third embodiment of the present invention. An image forming apparatus 220 shown in FIG. 6 is an intermediate transfer type image forming apparatus. In the housing 400, four electrophotographic photoreceptors 401a to 401d (for example, the electrophotographic photoreceptor 401a is yellow and the electrophotographic photoreceptor 401b is magenta). The electrophotographic photosensitive member 401c can form an image of cyan and the electrophotographic photosensitive member 401d can form a black color) are arranged in parallel along the intermediate transfer belt 409.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toners of four colors of black, yellow, magenta and cyan accommodated in toner cartridges 405a to 405d. These toners satisfy the condition that the average shape factor is 100 to 140. Further, the primary transfer rolls 410a to 410d are in contact with the electrophotographic photosensitive members 401a to 401d via the intermediate transfer belt 409, respectively.

  Further, a laser light source (exposure device) 403 is disposed at a predetermined position in the housing 400, and the surfaces of the electrophotographic photoreceptors 401a to 401d after charging are irradiated with laser light emitted from the laser light source 403. Is possible. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photoreceptors 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner. Here, by combining the electrophotographic photosensitive members 401a to 401d with each color toner having an average shape factor of 100 or more and 140 or less, even in a tandem type color image forming apparatus, high image quality and reduction of environmental load are achieved. Can be achieved at a high level.

  The intermediate transfer belt 409 is supported with a predetermined tension by a driving roll 406, a back roll 408, and a tension applying roll 407, and can rotate without causing deflection due to the rotation of these rolls. The secondary transfer roll 413 is disposed so as to contact the back roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 that has passed between the back roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is transferred to the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414 that are in contact with each other.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. There may be. Conventionally known resins can be used as the resin material used as the base material of the intermediate transfer member in the belt shape. For example, polyimide resin, polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene terephthalate (PAT), ethylenetetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend material, polyester Resin materials such as polyether ether ketone and polyamide, and resin materials using these as main raw materials. Furthermore, a resin material and an elastic material can be blended and used.

  As an elastic material, polyurethane, chlorinated polyisoprene, NBR, chloropyrene rubber, EPDM, hydrogenated polybutadiene, butyl rubber, silicone rubber, or the like can be used, or a material obtained by blending two or more kinds can be used. If necessary, a conductive agent imparting electronic conductivity or a conductive agent having ionic conductivity is added to the resin material and elastic material used for these base materials in combination of one kind or two or more kinds. Among these, it is preferable to use a polyimide resin in which a conductive agent is dispersed from the viewpoint of excellent mechanical strength. As the conductive agent, a conductive polymer such as carbon black, metal oxide, or polyaniline can be used.

  When a belt-shaped configuration such as the intermediate transfer belt 409 is employed as the intermediate transfer member, generally the thickness of the belt is preferably 50 μm or more and 500 μm or less, more preferably 60 μm or more and 150 μm or less, depending on the hardness of the material Can be selected as appropriate.

  For example, a belt made of a polyimide resin in which a conductive agent is dispersed is 5 to 20% by mass as a conductive agent in a polyamic acid solution, which is a polyimide precursor, as described in JP-A-63-311263. After the carbon black is dispersed, the dispersion is cast on a metal drum and dried, and then the film peeled off from the drum is stretched at a high temperature to form a polyimide film. Can be produced.

  The film forming is generally performed by injecting a polyamic acid solution stock solution in which a conductive agent is dispersed into a cylindrical mold and heating at, for example, 100 ° C. or more and 200 ° C. or less while rotating at 500 rpm or more and 2000 rpm or less. The film is formed into a film by a centrifugal molding method while rotating the cylindrical mold with a number, and then the obtained film is demolded in a semi-cured state and covered with an iron core, and is polyimideized at a high temperature of 300 ° C. or higher. It can be carried out by allowing the reaction (ring-closing reaction of polyamic acid) to proceed and main curing. In addition, the film-forming stock solution is cast on a metal sheet to a uniform thickness and heated to 100 ° C. or higher and 200 ° C. or lower to remove most of the solvent, and then gradually increased to a temperature of 300 ° C. or higher. There is also a method in which the temperature is raised to form a polyimide film. The intermediate transfer member may have a surface layer.

  When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  As shown in FIGS. 4 and 5, a preferred embodiment of the process cartridge of the present invention includes an electrophotographic photosensitive member 207, a charging device 208, a developing device 211, a cleaning device (cleaning means) 213, and an exposure device. An opening 218 and an opening 217 for static elimination exposure are combined and integrated using a mounting rail 216. The developing device 211 supplies toner to the electrophotographic photosensitive member 207.

  The process cartridge according to the present embodiment is attached to and detached from the image forming apparatus main body including the transfer device 212 or the primary transfer member 212a, the secondary transfer member 212b, the fixing device 215, and other components not shown. The image forming apparatus is configured together with the main body of the image forming apparatus.

  In addition, as shown in FIG. 6, another process cartridge in the present embodiment includes a charging roll 402a, an electrophotographic photosensitive member 401a, a cleaning blade 415a, and a developing device 404a that are integrated, for example, a process cartridge for black. Is configured. Similarly, the charging roll 402b, the electrophotographic photosensitive member 401b, the cleaning blade 415b, and the developing device 404b are integrated to form a yellow process cartridge. The charging roll 402c, the electrophotographic photosensitive member 401c, the cleaning blade 415c, and the developing unit The device 404c is integrated to form a magenta process cartridge, and the charging roll 402d, the electrophotographic photosensitive member 401d, the cleaning blade 415d, and the developing device 404d are integrated to form a cyan process cartridge.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” represents “part by mass”.

<Example 1>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating with a thickness of 5 μm, followed by brush coating to form an adhesive layer with a thickness of 20 μm. The conductive support A was formed.

Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
A mixture having the following composition was kneaded with an open roll, an elastic layer was formed on the surface of the conductive support A using an injection molding machine, vulcanized, and then a conductive elastic roll A having a diameter of 14 mm was obtained by polishing. Table 1 shows defects during molding.

100 parts by mass of rubber material (epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber Gechron 3106: manufactured by Nippon Zeon Co., Ltd.)
Conductive agent (carbon black Asahi Thermal: manufactured by Asahi Carbon Co., Ltd.) 15 parts by mass conductive agent (Ketjen Black EC: manufactured by Lion) 5 parts by mass ionic conductive agent (lithium perchlorate) 1 part by mass vulcanizing agent (sulfur 200 mesh : Tsurumi Chemical Co., Ltd.) 1 part by mass vulcanization accelerator (Noxeller DM: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 2.0 parts by mass vulcanization accelerator (Noxeller TT: manufactured by Ouchi New Chemical Co., Ltd.) 0.5 Mass parts Vulcanization accelerating aid (Zinc oxide, zinc oxide 1 type: manufactured by Shodo Chemical Co., Ltd.) 3 parts by mass Stearic acid 1.5 parts by mass

-Formation of surface layer-
Dispersion A obtained by dispersing the following mixture with a bead mill is diluted with MEK, dip-coated on the surface of the conductive elastic roll A, and then heated and dried at 180 ° C. for 30 minutes to form a surface layer having a thickness of 7 μm. The conductive elastic roll 1 was obtained.

100 parts by mass of polymer material (saturated copolymer polyester resin solution Byron 30SS: manufactured by Toyobo Co., Ltd.)
Curing agent 26.3 parts by mass (amino resin solution Super Becamine G-821-60: manufactured by Dainippon Ink & Chemicals, Inc.)
Conductive agent 10 parts by mass (carbon black MONARCH1000: manufactured by Cabot Corporation)

<Example 2>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support B.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll B was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 2 was obtained.

<Example 3>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. The conductive support C was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR solution (40 parts by mass of NBR Nipol 1043: Nippon Zeon Co., Ltd. and 60 parts by mass of toluene)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll C was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 3 was obtained.

<Example 4>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support D.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR solution (40 parts by mass of (NBR Nipol 1042: manufactured by Nippon Zeon) and 60 parts by mass of toluene)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll D was obtained.

-Formation of surface layer-
A conductive elastic roll 4 was obtained according to Example 1.

<Example 5>
-Formation of adhesive layer-
The following mixture was mixed in a ball mill for 1 hour on the surface of a conductive support composed of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating with a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support E.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR solution (40 parts by mass of NBR Nipol 1041: Nippon Zeon Co., Ltd. and 60 parts by mass of toluene)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll E was obtained.

-Formation of surface layer-
A conductive elastic roll 5 was obtained according to Example 1.

<Example 6>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. The conductive support F was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR solution (40 parts by mass of NBR Nipol DN401: Nippon Zeon) and 60 parts by mass of toluene)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll F was obtained.

-Formation of surface layer-
A conductive elastic roll 6 was obtained according to Example 1.

<Example 7>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. And a conductive support G was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: Conductor made by Road Far East Co., Ltd. 2 parts by mass (carbon black Ketjen Black EC: made by Ketjen Black International)
NBR (Nipol 1312: manufactured by Nippon Zeon Co., Ltd.) 30 parts by mass

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll G was obtained.

-Formation of surface layer-
A conductive elastic roll 7 was obtained according to Example 1.

<Example 8>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. The conductive support H was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
NBR (Nipol DN601: manufactured by Nippon Zeon Co., Ltd.) 15 parts by mass

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll H was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 8 was obtained.

<Example 9>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support I.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: Conductor made by Road Far East Co., Ltd. 2 parts by mass (carbon black Ketjen Black EC: made by Ketjen Black International)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
20 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll I was obtained.

-Formation of surface layer-
A conductive elastic roll 9 was obtained according to Example 1.

<Example 10>
<Formation of adhesive layer>
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. And a conductive support J was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
40 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll J was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 10 was obtained.

<Example 11>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support K.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)
NBR (Nipol DN601: manufactured by Nippon Zeon Co., Ltd.) 50 parts by mass

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll K was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 11 was obtained.

<Example 12>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. To obtain a conductive support L.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll L was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 12 was obtained.

<Example 13>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. The conductive support M was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
100 parts by mass of adhesive (polyolefin adhesive Chemlok 204: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll M was obtained.

-Formation of surface layer-
A conductive elastic roll 13 was obtained according to Example 1.

<Example 14>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to trivalent chromic acid treatment after electroless nickel plating with a thickness of 5 μm. A layer was formed to obtain a conductive support N.

[First adhesive: Adhesive that adheres to the conductive support]
100 parts by mass of adhesive (polyolefin adhesive Chemlok 204: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll N was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 14 was obtained.

<Comparative Example 1>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating with a thickness of 5 μm, followed by brush coating to form an adhesive layer with a thickness of 20 μm. The conductive support 21 was obtained.

Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

-Formation of elastic layer-
A conductive elastic roll a was obtained according to Example 1.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 21 was obtained.

<Comparative example 2>
-Formation of adhesive layer-
The following mixture was mixed with a ball mill for 1 hour on the surface of a conductive support composed of SUM23L with a diameter of 8 mm and plated with 5 μm of electroless nickel and then hexavalent chromic acid. A layer was formed to obtain a conductive support 22.

[First adhesive: Adhesive that adheres to the conductive support]
Adhesive 100 parts by mass (polyolefin adhesive XJ-150: manufactured by Road Far East)
2 parts by mass of conductive agent (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll b was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 22 was obtained.

<Comparative Example 3>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating having a thickness of 5 μm, and then an adhesive layer having a thickness of 10 μm by brush coating. The conductive support 23 was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
100 parts by mass of adhesive (polyolefin adhesive Chemlok 204: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll c was obtained.

-Formation of surface layer-
A conductive elastic roll 23 was obtained according to Example 1.

<Comparative example 4>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to trivalent chromic acid treatment after electroless nickel plating with a thickness of 5 μm. The layer was formed and the electroconductive support body 24 was obtained.

[First adhesive: Adhesive that adheres to the conductive support]
100 parts by mass of adhesive (polyolefin adhesive Chemlok 204: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

[Second adhesive: Adhesive that adheres to the elastic layer]
Adhesive 100 parts by mass (polyolefin adhesive Chemlok 258: manufactured by Road Far East)
Conductive agent 4 parts by mass (carbon black ketjen black EC: manufactured by ketjen black international)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll d was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 24 was obtained.

<Comparative Example 5>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating with a thickness of 5 μm, followed by brush coating to form an adhesive layer with a thickness of 20 μm As a result, a conductive support 25 was obtained.

Adhesive 100 parts by mass (phenolic resin adhesive Metaloc U-20: manufactured by Toyo Chemical Laboratories)
30 parts by mass of NBR (Nipol DN601: manufactured by Nippon Zeon)

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll e was obtained.

-Formation of surface layer-
A conductive elastic roll 25 was obtained according to Example 1.

<Comparative Example 6>
-Formation of adhesive layer-
The following mixture was mixed for 1 hour with a ball mill on the surface of a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid after electroless nickel plating with a thickness of 5 μm, followed by brush coating to form an adhesive layer with a thickness of 20 μm As a result, a conductive support 26 was obtained.

Adhesive 100 parts by mass (phenolic resin adhesive Metaloc U-20: manufactured by Toyo Chemical Laboratories)
NBR (Nipol DN601: manufactured by Nippon Zeon Co., Ltd.) 10 parts by mass

-Formation of elastic layer-
In accordance with Example 1, a conductive elastic roll f was obtained.

-Formation of surface layer-
In accordance with Example 1, a conductive elastic roll 26 was obtained.

[Evaluation]
After the conductive elastic roll 1 was stored in a high temperature and high humidity (45 ° C., 95% RH) environment for 10 days, the surface state was observed and the elastic layer including the surface layer was peeled off, and the surface of the conductive support was observed. The results are shown in Table 1.
A: No change from the surface state before the elastic layer was formed.
A: Pinholes were observed in the adhesive layer and / or the conductive support.
Δ: Cracks were observed in the adhesive layer and / or the conductive support.
X: Peeling was observed on the adhesive layer and / or d conductive support.
XX: The conductive support was corroded and raised, and peeling was observed on the adhesive layer and / or the conductive support.

In order to see the adhesive strength of the adhesive layer, the elastic layer portion of the conductive elastic roll 1 was cut with a cutter, and the elastic layer was peeled by hand. The results are shown in Table 1.
A: Difficult to peel and / or breakage of elastic layer due to strong adhesion.
(Triangle | delta): Although there exists resistance in the interface of an electroconductive support body and an adhesive layer, or the interface of an adhesive layer and an elastic layer, it can peel.
X: Easily peeled off at the interface between the conductive support and the adhesive layer or at the interface between the adhesive layer and the elastic layer.

The conductive elastic roll 1 after storage for 10 days in a high-temperature and high-humidity (45 ° C., 95% RH) environment is mounted as a charging roll on a drum cartridge manufactured by Fuji Xerox Co., Ltd. A 50% halftone image was printed in an environment of 10 ° C. and 15% RH and in an environment of 28 ° C. and 85% RH. The results are shown in Table 1.
A: Density unevenness, white spots, and color spots are not generated.
○: Minor density unevenness, white spots, and color spots partially occur.
Δ: Minor density unevenness, white spots, and color spots occur.
X: Density unevenness, white spots, and color spots occur.

  Tables 1 to 6 show the results of the above evaluation of the conductive rolls 1 to 14 and the conductive rolls 21 to 26 of Example 1 to Example 14 and Comparative Example 1 to Comparative Example 6.

  As an application example of the present invention, there is application to an image forming apparatus such as a copying machine or a printer using an electrophotographic system.

  31 conductive support, 32 adhesive layer (second adhesive layer), 33 first adhesive layer, 34 elastic layer, 35 intermediate layer, 36 surface layer, 200, 210, 220 image forming apparatus, 206 exposure apparatus, 207 Photoconductor, 207 Electrophotographic photoconductor, 208 Charging device, 209 Power supply, 211 Developing device, 212a Primary transfer member, 212b Secondary transfer member, 212 transfer device, 213 Cleaning device, 214 Static eliminator, 215 Fixing device, 216 Rail, 217, 218 opening, 400 housing, 401a, 401b, 401c, 401d electrophotographic photosensitive member, 402a, 402b, 402c, 402d charging roll, 403 laser light source, 404a, 404b, 404c, 404d developing device, 405a, 405b , 405c, 405d Toner cart Wedge, 406 drive roll, 407 tension roll, 408 backup roll, 409 intermediate transfer belt, 410a, 410b, 410c, 410d primary transfer roll, 411 tray, 412 transfer roll, 413 secondary transfer roll, 414 fixing roll, 415a , 415b, 415c, 415d Cleaning blade, 416 Cleaning blade, 500 Transfer medium.

Claims (7)

It is a charging roll that contacts a member to be charged in a state where a voltage is applied and charges the member to be charged,
The charging roll has at least an adhesive layer and an elastic layer sequentially formed on a conductive support,
The charging roll according to claim 1, wherein the adhesive layer contains a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber. It is a charging roll that contacts a member to be charged in a state where a voltage is applied and charges the member to be charged,
The charging roll has at least two adhesive layers and an elastic layer sequentially formed on a conductive support,
The charging roll, wherein the adhesive layer that adheres to the elastic layer contains a polyolefin-based adhesive and acrylonitrile-butadiene copolymer rubber.   The charging roll according to claim 2, wherein the adhesive layer that adheres to the conductive support is made of a polyolefin-based adhesive.   The charging roll according to claim 2, wherein the adhesive layer that adheres to the conductive support is made of a chlorinated rubber adhesive.   The charging roll according to any one of claims 1 to 4, wherein the conductive support is subjected to a trivalent chromium electroless nickel plating treatment.   A process cartridge comprising at least the charging roll according to any one of claims 1 to 5.   6. An image forming apparatus comprising at least an image holding member and a charging unit that contacts the image holding member and charges the surface thereof, wherein the charging unit is the charging according to claim 1. An image forming apparatus comprising a roll.

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