JP2014228800A - Method of manufacturing charging member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a charging member which hardly causes faulty cleaning even when the charging member is reused.SOLUTION: In a method of manufacturing a charging member having a conductive support body and an elastic layer being a surface layer, the elastic layer has, on its surface, an area hardened by irradiation with an electron beam, the hardened area supports spherical resin particles in a state where they are exposed to the surface of the elastic layer, and thereby the surface is roughened. The method of manufacturing the charging member includes steps (1-1) to (1-3): the step (1-1) of forming, on the support body, a vulcanized rubber layer including specific spherical resin particles and vulcanized rubber having an unsaturated bond; the step (1-2) of polishing the surface of the vulcanized rubber layer to make a part of the spherical resin particles be exposed; the step (1-3) of irradiating, with the electron beam, the surface of the vulcanized rubber layer with a part of the spherical resin particles exposed thereon, which is obtained in the step (1-2), thereby hardening the surface to form the elastic layer.

Description

  The present invention relates to a method for manufacturing a charging member used in an electrophotographic apparatus or the like.

  In order to secure a uniform nip with the charged body and prevent damage to the charged body, the charging member used for contact charging of the charged body such as an electrophotographic photosensitive member is made of rubber or thermoplastic elastomer. The structure provided with the elastic layer containing is common. Patent Document 1 discloses a charging member that has a flexible surface that can form a sufficient nip width with a member to be charged and that hardly causes a cleaning failure on the member to be charged.

  Specifically, it has a conductive support and an elastic layer which is a surface layer, and the elastic layer has a region cured by electron beam irradiation on the surface, and the cured region has a specific area. It is a charging member that supports spherical inorganic particles in a state of being exposed on the surface, and thereby has a roughened surface.

JP 2012-037875 A

  In recent years, from the viewpoint of reducing the environmental load, it has been studied to recover the performance equivalent to that of a new article by cleaning the surface of the charging member that has been used for a long time and to reuse the charging member.

  Therefore, the present inventor cleans the dirt adhering to the surface of the charging member according to Patent Document 1 that has been used for a long time, and incorporates the cleaned charging member into the process cartridge again to form an electrophotographic image. went. As a result, the quality of the electrophotographic image may be deteriorated due to poor cleaning of the charged body. In addition, defective cleaning means that residual toner existing on the surface of the electrophotographic photosensitive member to be removed by a cleaning member (cleaning blade or the like) slips through the cleaning member. Residual toner that has passed through the cleaning member may deteriorate the quality of the electrophotographic image formed by the next electrophotographic image forming cycle.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a charging member that hardly causes defective cleaning even when reused. Another object of the present invention is to provide an electrophotographic apparatus capable of forming a high-quality electrophotographic image stably over a long period of time.

According to one embodiment of the present invention, a conductive support and an elastic layer which is a surface layer are provided, and the elastic layer has a region cured by irradiation with an electron beam on the surface, and is cured. The region is a method for producing a charging member in which spherical resin particles are supported while being exposed on the surface of the elastic layer, whereby the surface is roughened.
(1-1) Vulcanization containing spherical resin particles made of at least one resin selected from phenol resin, polyacrylonitrile resin, nylon resin, and polypropylene resin and vulcanized rubber having an unsaturated bond on the support. Forming a rubber layer;
(1-2) polishing the surface of the vulcanized rubber layer to expose a part of the spherical resin particles;
(1-3) The elastic layer is formed by irradiating the surface of the vulcanized rubber layer, in which part of the spherical resin particles are exposed, obtained by the step (1-2) with an electron beam to cure the surface. And a process of
Is provided.

According to another aspect of the present invention, it has a conductive support and an elastic layer that is a surface layer, and the elastic layer has a region cured by electron beam irradiation on the surface, and the cured The region formed is a method for producing a charging member that supports the spherical resin particles in a state of being exposed on the surface of the elastic layer, whereby the surface is roughened.
(2-1) forming an unvulcanized rubber layer containing an unvulcanized rubber having an unsaturated bond on the support;
(2-2) At least one resin selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin on the surface of the unvulcanized rubber layer. A step of burying a part of the spherical resin particles by press-contacting the resulting spherical resin particles;
(2-3) Vulcanized rubber obtained by vulcanizing the unvulcanized rubber layer in which part of the spherical resin particles are buried, obtained by the step (2-2), and in which part of the spherical resin particles are buried. Forming a layer;
(2-4) The surface of the vulcanized rubber layer obtained by the step (2-3), in which a part of the spherical resin particles are buried, is irradiated with an electron beam to cure the surface and form the elastic layer. And a process of
Is provided.

  According to the present invention, it is possible to obtain a method for manufacturing a charging member that suppresses the occurrence of defective cleaning even when used for a long period of time or when it is washed and reused. In addition, according to the present invention, an electrophotographic apparatus capable of forming a high-quality electrophotographic image stably over a long period of time can be obtained.

It is a schematic diagram which shows the surface form of a charging roller. It is a schematic diagram which shows the structural example of a charging roller. It is a block diagram showing an electrophotographic apparatus having a charging member. It is a block diagram which shows an electron beam irradiation apparatus. It is a block diagram which shows the washing | cleaning apparatus of a charging roller.

  As a result of repeated investigations on the cause of the occurrence of defective cleaning by the charging member according to Patent Document 1, the inventor estimated the generation mechanism as follows.

  First, an electrophotographic image forming process will be described with reference to a configuration diagram of an electrophotographic apparatus having a charging member in FIG. An electrophotographic photosensitive member (hereinafter abbreviated as “photosensitive member”) 31 as a member to be charged includes a conductive support 31b and a photosensitive layer 31a formed on the support 31b, and has a cylindrical shape. Then, it is driven at a predetermined peripheral speed in the clockwise direction in the figure around the shaft 31c.

  The charging roller 32 is disposed in contact with the photoconductor 31 to charge the photoconductor to a predetermined potential. The charging roller 32 includes a cored bar 32a and an elastic layer 31b formed on the cored bar 32a. Both ends of the cored bar 32a are pressed against the electrophotographic photosensitive member 31 by a pressing unit (not shown). As the motor 31 is driven, it is driven to rotate. By applying a predetermined DC voltage of the cored bar 32a by the rubbing electrode 33a with the power source 33, the photosensitive member 31 is charged to a predetermined potential.

  The charged photoreceptor 31 then forms an electrostatic latent image corresponding to the target image information on its peripheral surface by the exposure means 34. The electrostatic latent image is then sequentially visualized as a toner image by the developing member 35. The toner images are sequentially transferred to the transfer material 37. The transfer material 37 is conveyed from a paper supply unit (not shown) to the transfer unit between the photoconductor 31 and the transfer unit 36 at an appropriate timing in synchronization with the rotation of the photoconductor 31. The transfer means 36 is a transfer roller, and the toner image on the side of the photoconductor 31 is transferred to the transfer material 37 by charging from the back of the transfer material 37 with a polarity opposite to that of the toner. The transfer material 37 having received the transfer of the toner image on the surface is separated from the photoreceptor 31 and conveyed to a fixing means (not shown) to fix the toner, and is output as an image formed product. The toner remaining on the surface of the photoreceptor 31 is removed from the peripheral surface of the photoreceptor 31 after the image transfer by a cleaning member 38 represented by an elastic blade. The cleaned peripheral surface of the photoreceptor 31 moves to the electrophotographic image forming process of the next cycle.

  In the above-described series of electrophotographic image forming processes, the surface of the photoreceptor is charged by discharging in a gap near the contact nip between the charging roller and the photoreceptor. At that time, discharge products generated in the vicinity of the charging roller, abrasion powder of the photosensitive member, and the like adhere to the surface of the photosensitive member. Then, they are accumulated on the surface of the photosensitive member by being pressed against the surface of the photosensitive member at the nip portion between the charging roller and the photosensitive member. Then, the frictional force between the photosensitive member and the elastic blade as the cleaning member gradually increases. Eventually, the elastic blade starts to vibrate due to the high frictional force between the photoconductor and the elastic blade, and the residual toner on the surface of the photoconductor cannot be sufficiently removed. As a result, the electrophotographic image forming process of the next cycle is performed on the peripheral surface of the photoreceptor having the residual toner attached on the surface.

  Here, the increase in the frictional force between the photosensitive member and the elastic blade is noticeable in the charging roller having the surface layer made of the elastic member. A charging roller having a surface layer made of an elastic material has a flexible surface, so even if the surface is uneven, it is liable to be crushed by contact with the photosensitive member, and the contact area at the nip portion between the charging roller and the photosensitive member is large growing. Therefore, it is considered that a substance that causes an increase in frictional force such as a discharge product is easily fixed to the surface of the photoreceptor.

  The charging member according to Patent Document 1, in which toner or the like has adhered to the surface after long-term use, has washed the surface, and as a result, inorganic fine particles having low adhesion to the elastic layer fall off from the surface of the elastic layer. Is smoothing. For this reason, the contact area at the nip portion between the charging roller and the photosensitive member is increased, and it is considered that a substance that causes an increase in frictional force such as a discharge product is fixed on the surface of the photosensitive member.

  Therefore, the present inventor has intensively studied for the purpose of obtaining a charging member in which the spherical particles exposed on the surface are prevented from falling off even by the surface cleaning process, and hardly cause poor cleaning when reused. Went.

  As a result, the charging member formed through the following steps (1-1) to (1-3) or the following steps (2-1) to (2-4) can well achieve the above-mentioned object. I found.

(1-1) A vulcanized rubber containing spherical resin particles made of at least one resin selected from a phenol resin, a polyacrylonitrile resin, a nylon resin, and a polypropylene resin and a vulcanized rubber having an unsaturated bond on a support. Forming a layer;
(1-2) polishing the surface of the vulcanized rubber layer to expose a part of the spherical resin particles;
(1-3) By irradiating the surface of the vulcanized rubber layer obtained by the step (1-2) with a part of the spherical resin particles exposed to an electron beam, the surface is cured to form an elastic layer. Process.

(2-1) A step of forming an unvulcanized rubber layer containing an unvulcanized rubber having an unsaturated bond on the support;
(2-2) At least one resin selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin on the surface of the unvulcanized rubber layer. A step of burying a part of the spherical resin particles by press-contacting the resulting spherical resin particles;
(2-3) Vulcanized rubber obtained by vulcanizing the unvulcanized rubber layer in which part of the spherical resin particles are buried, obtained by the step (2-2), and in which part of the spherical resin particles are buried. Forming a layer;
(2-4) The elastic layer is formed by irradiating the surface of the vulcanized rubber layer in which a part of the spherical resin particles obtained by the step (2-3) is embedded with an electron beam to cure the surface. Process.

  The reason why the charging member formed through the above steps (1-1) to (1-3) or (2-1) to (2-4) can satisfactorily achieve the above-mentioned purpose is that the specific reason is as follows. It is presumed that the spherical resin particles and the vulcanized rubber having an unsaturated bond were co-crosslinked at the interface, and the spherical resin particles were firmly held by the vulcanized rubber layer.

  Hereinafter, preferred embodiments of the present invention will be described.

<Charging member>
FIG. 2 shows a configuration diagram of a charging roller as the charging member of the present invention.

  The charging roller 20 includes a cored bar 21 and an elastic layer 22 formed on the cored bar 21. The charging member according to the present invention can be used as the charging roller 32 of the electrophotographic apparatus shown in FIG.

  FIG. 1 is a schematic diagram showing the form of the surface of the charging roller of the present invention. The elastic layer of the charging roller according to the present invention contains at least one spherical resin particle 11 selected from specific spherical resin particles, and the surface is roughened by the spherical resin particles. Further, the surface of the elastic layer is cured by electron beam irradiation, and at least some of the spherical resin particles described above are partially exposed to the elastic layer surface and cured by electron beam irradiation. It is supported by the region 12 of the elastic layer. Furthermore, the rubber layer which has a specific spherical resin particle and an unsaturated bond is co-crosslinked in the interface by electron beam irradiation. In the deep layer portion of the elastic layer, there is a region 13 that is not cured by an electron beam in order to maintain the flexibility of the elastic layer.

  Since the spherical resin particles are supported by the cured region 12, even when the elastic layer contacts a charged body such as a photoconductor, the spherical resin particles are less likely to be buried in the elastic layer at the nip. As a result, even in the nip, the high-hardness spherical resin particles can maintain the uneven shape of the surface in a state where a part of the spherical resin particles is exposed on the surface of the elastic layer, and the contact area with the photoreceptor can be reduced. . In addition, since the specific spherical resin particles have a spherical shape, excessive wear and damage to the surface of the photoconductor can be suppressed even if a portion exposed from the elastic layer surface directly contacts the photoconductor.

  Moreover, the hardening process by electron beam irradiation can maintain the low layer hardness (MD-1 hardness 50 or more and less than 80) by hardening only the surface part of an elastic layer.

  Therefore, charging unevenness due to poor contact between the charging roller and the object to be charged, which is recognized when the entire elastic layer is hardened (for example, MD-1 hardness of 80 degrees or more), or the surface of the charging roller over time. The occurrence of image unevenness due to adhesion of toner and external additives can be suppressed.

  Then, each element which comprises a charging member is demonstrated in order.

(Specific spherical resin particles)
Specific spherical resin particles are exposed in the elastic layer used in the present invention. The specific spherical resin particle fat refers to spherical particles composed of the following resins.

  At least one resin selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin.

  These resins are easily cross-linked by electron beam irradiation. In particular, when these resins coexist with raw material rubber having an unsaturated bond, they are easily cross-linked when irradiated with an electron beam. In particular, in the chemical structure of the polymer chain, a resin having a vinyl type structure and a resin having α-hydrogen are more easily cross-linked. Therefore, in this invention, the spherical resin particle containing at least 1 sort (s) of resin chosen from a polystyrene resin, a polyurethane resin, a nylon resin, a polyethylene resin, and a polypropylene resin is used more suitably.

  The particle diameter of the spherical resin particles is preferably 2 μm or more and 80 μm or less. If the particle diameter is 2 μm or more, an increase in the contact area with the photoreceptor due to the small particle diameter can be suppressed. Further, when the particle diameter is 80 μm or less, it is possible to suppress the contamination of the toner on the surface of the charging roller due to the increase in the surface roughness of the elastic layer due to the particle size. A more preferable range of the particle diameter of the spherical resin particles is 5 μm or more and 40 μm or less. The surface of the elastic layer is roughened by these spherical resin particles, and the degree of roughening is preferably such that the ten-point average roughness (Rzjis) of the elastic layer surface is 3 μm or more and 20 μm or less.

  The particle diameter of the spherical resin particles is a “length average particle diameter” determined by the following method. First, the spherical resin particles were observed with a scanning electron microscope (manufactured by JEOL Ltd., trade name: JEOL LV5910) and imaged, and the captured images were image analysis software (trade name: Image-Pro Plus, produced by Planetron). ) To analyze. In the analysis, the number of pixels per unit length is calibrated from the micron bar at the time of photography, and for 50 particles randomly selected from the photograph, the directional diameter is measured from the number of pixels on the image, and the arithmetic average particle The diameter is obtained and used as the particle diameter of the spherical resin particles.

Furthermore, regarding the sphericity of the spherical resin particles, the value of the shape factor SF1 shown below is preferably 100 or more and 160 or less. Here, the shape factor SF1 is an index represented by the following formula (1), and the closer to 100, the closer to a spherical shape. If the shape factor is 160 or less, even if the spherical resin particles are exposed on the surface of the elastic layer and are in direct contact with the photoreceptor, excessive wear and damage to the photoreceptor can be suppressed. The shape factor SF1 of the spherical resin particles used in the present invention is measured by the following method. Similar to the particle size, image information taken with a scanning electron microscope is input to an image analyzer (trade name: Luzex3, manufactured by Nireco). For 50 randomly selected particle images, the following equation (1) is used. calculate.
SF1 = {(MXLNG) ² / AREA} × (π / 4) × (100) (1)
(Where MXLNG is the absolute maximum length of the particle and AREA is the projected area of the particle).

  The spherical resin particles exposed on the surface of the elastic layer may be used in combination of two or more kinds or a copolymer of each resin.

(Rubber composition having an unsaturated bond)
The elastic layer includes a rubber composition having an unsaturated bond and specific spherical resin particles. The rubber composition having an unsaturated bond is a rubber composition obtained by blending a raw material rubber having an unsaturated bond with a crosslinking agent or the like.

  The raw rubber having an unsaturated bond is a raw rubber having a carbon double bond in a part of a polymer chain. Specific examples include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), ethylene-propylene-diene terpolymer rubber (EPDM). ), Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (GECO), acrylonitrile-butadiene copolymer (NBR), hydrogenated product of acrylonitrile-butadiene copolymer (H-NBR), chloroprene rubber (CR) Etc. Among these, more preferable raw rubbers are NR, IR, BR, SBR, NBR, and CR, which have many repeating units having an unsaturated bond.

  The rubber composition may contain a conductive agent, a filler, a processing aid, an anti-aging agent, a crosslinking aid, a crosslinking accelerator, a crosslinking acceleration aid, a crosslinking retarder, a dispersant and the like.

(Elastic layer)
In the present invention, the elastic layer means an elastic layer as a surface layer. The elastic layer can be multilayered. However, in the case of multilayering, it is necessary to form a layer containing spherical resin particles on the outermost surface. In the present invention, an adhesive layer can also be formed between the conductive support and the elastic layer.

  In the present invention, in order to maximize the effect of simplifying the production process, the elastic layer is most preferably a single layer, that is, the only elastic layer in the charging member according to the present invention. In this case, the thickness of the elastic layer is preferably 0.8 mm or more and 4.0 mm or less, particularly 1.2 mm or more and 3.0 mm or less in order to secure a nip width with the charged body.

  The surface of the elastic layer has a region cured by an electron beam (hereinafter also referred to as “cured region”). The thickness of the cured region is not particularly defined, but is preferably 0.5 times or more the average particle size (length average particle size) of the spherical resin particles to be used. By setting the thickness of the cured region to 0.5 times or more of the particle diameter, it is possible to more reliably suppress the spherical resin particles exposed on the surface from being buried in the elastic layer at the contact portion. . A more preferable thickness of the cured region is not less than the average particle diameter of the spherical resin particles and not more than 200 μm. By setting the thickness of the cured region by the electron beam to 200 μm or less, a sufficient nip width between the charging roller and the photoreceptor can be secured.

Examples of the method for confirming the thickness of the region subjected to the curing treatment include measurement of surface hardness using a universal hardness meter. The universal hardness is a physical property value obtained by pushing into an object while applying a load to the indenter, and is obtained as (test load) / (surface area of the indenter under the test load) (N / mm ² ). The universal hardness can be measured using, for example, a hardness measuring device such as an ultra micro hardness meter (trade name: H-100V, manufactured by Fischer). In this measuring device, an indenter such as a square weight is pushed into an object to be measured while applying a predetermined relatively small test load, and when the predetermined indentation depth is reached, the surface area with which the indenter contacts from the indentation depth And universal hardness from the above formula. That is, when the indenter is pushed into the object under constant load measurement conditions, the stress at that time with respect to the pushed-in depth is defined as universal hardness.

From the universal hardness measurement, a graph of the indentation depth (μm) on the horizontal axis and the hardness (N / mm ² ) on the vertical axis is obtained. In this graph, by taking the difference between before and after the electron beam treatment, the thickness of the hardened region and the degree of increase in hardness can be measured.

(Conductive support)
The conductive support is not particularly limited as long as it has conductivity, can support the elastic layer and the like, and can maintain the strength as the charging roller.

<Method for manufacturing charging member>
The manufacturing method of the charging member according to the present invention will be described below.

  The charging member according to the present invention has a conductive support and an elastic layer which is a surface layer, and the elastic layer has a region hardened by electron beam irradiation on the surface, and the cured The region supports the spherical resin particles in a state of being exposed on the surface of the elastic layer, whereby the surface is roughened. And the 1st aspect of the manufacturing method of this charging member has the following processes (1-1)-(1-3).

(1-1) On a conductive support, spherical resin particles made of at least one resin selected from a phenol resin, a polyacrylonitrile resin, a nylon resin, and a polypropylene resin, and an unvulcanized rubber having an unsaturated bond A step of curing the rubber composition to form a vulcanized rubber layer;
(1-2) A step of polishing the surface of the vulcanized rubber layer to expose a part of the spherical resin particles;
(1-3) A step of irradiating the surface of the vulcanized rubber layer obtained by the step (1-2) with a part of the spherical resin particles exposed to an electron beam to cure the surface.

Each step will be described below.
(1-1)
First, a vulcanized rubber layer containing specific spherical resin particles and a vulcanized rubber having an unsaturated bond is formed on a conductive support. A specific example will be described below. First, an unvulcanized rubber composition containing a raw rubber having an unsaturated bond constituting the elastic layer and specific spherical resin particles is prepared.

  In this production method, since there is a step of polishing the surface later, it is necessary to select spherical resin particles that can maintain a spherical shape even after polishing. The index is preferably a resin having a large Izod impact strength (ASTM D256). Specifically, it is preferable to use a resin having an Izod impact strength of 5 kg · cm / cm or more, and particularly an Izod impact strength of 10 kg · cm / cm or more. Examples of the material having such physical properties include phenol resin, polyacrylonitrile resin, nylon resin, and polypropylene resin.

  The content of the spherical resin particles in the unvulcanized rubber composition is preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the raw rubber. If it is 5 parts by mass or more, a sufficient amount of spherical resin particles can be present on the surface, and the contact area with the photoreceptor can be particularly reduced. Moreover, if it is 50 mass parts or less, it can suppress that the compounding quantity of a spherical resin particle increases and an elastic layer becomes hard.

Subsequently, the peripheral surface of the conductive support is covered with an unvulcanized rubber composition and formed into a roller shape. This is referred to as an unvulcanized rubber roller. Examples of the method for forming the roller shape include the following methods (a) to (c).
(A) A method of extruding an unvulcanized rubber composition into a tube shape with an extruder and inserting a core metal into the tube (b) A core metal with an unvulcanized rubber composition by an extruder equipped with a crosshead A method for obtaining a molded body having a desired outer diameter by co-extrusion around a cylinder (c) An unvulcanized rubber composition is injected into a mold having a desired outer diameter using an injection molding machine. How to get the body.

  Above all, the above (b) is most preferable because continuous production is easy, the number of steps is small, and it is suitable for low-cost production.

  Next, the unvulcanized rubber roller is heated to obtain a vulcanized rubber roller. Specific examples of the heat treatment method include hot blast furnace heating using a gear oven, superheat vulcanization using far infrared rays, and steam heating using a vulcanizer. Of these, hot stove heating and far-infrared overheating are preferable because they are suitable for continuous production.

(1-2)
By polishing the surface of the vulcanized rubber layer of the vulcanized rubber roller obtained in the step (1-1), a part of each particle of the spherical resin particles is exposed on the surface of the rubber layer. . At this time, polishing is performed under the condition that the spherical resin particles on the surface maintain a spherical shape even if the polishing treatment is performed. Examples of the method for polishing the surface of the vulcanized rubber layer include a traverse polishing method in which a grindstone or a roller is moved in the thrust direction of the roller for polishing, and a roller wider than the roller length while rotating the roller about the center of the core metal shaft. A plunge polishing method in which the polishing grindstone is cut without reciprocating is mentioned. The plunge polishing method has an advantage that the entire width of the rubber roller can be polished at once, and is more preferable because the processing time can be shortened compared to the cylindrical polishing method of the traverse.

(1-3)
Finally, the surface of the vulcanized rubber layer after polishing is irradiated with an electron beam, and the surface is cured to form an elastic layer having a cured region on the surface.

  FIG. 4 shows a schematic diagram of an electron beam irradiation apparatus. As the electron beam irradiation apparatus that can be used in the present invention, an apparatus that irradiates the roller surface with an electron beam while rotating the rubber roller after polishing can be suitably used. For example, as shown in FIG. 4, an electron beam generator 41, an irradiation chamber 42, and an irradiation port 43 are provided.

The electron beam generator 41 includes a terminal 44 that generates an electron beam, and an acceleration tube 45 that accelerates the electron beam generated at the terminal 44 in a vacuum space (acceleration space). The inside of the electron beam generator is kept at a vacuum of 10 ⁻³ Pa to 10 ⁻⁶ Pa by an unillustrated vacuum pump or the like in order to prevent electrons from colliding with gas molecules and losing energy. When the filament 46 is heated by current from a power source (not shown), the filament 46 emits thermoelectrons, and only those thermoelectrons that have passed through the terminal 44 are taken out as electron beams. Then, after being accelerated in the acceleration space in the accelerating tube 45 by the acceleration voltage of the electron beam, it penetrates the irradiation port foil 47 and is irradiated to the polished rubber roller 48 conveyed in the irradiation chamber 42 below the irradiation port 43. The

  When the rubber roller 48 after polishing is irradiated with an electron beam, the inside of the irradiation chamber 42 can be filled with nitrogen to reduce the oxygen concentration. The polished rubber roller 48 moves in the irradiation chamber while being rotated by the roller rotating member 49. In addition, the periphery of the electron beam generation part 41 and the irradiation chamber 42 is shielded by lead (not shown) so that X-rays that are secondarily generated during electron beam irradiation do not leak to the outside.

  The irradiation port foil 47 is made of a metal foil, and separates the vacuum atmosphere in the electron beam generator and the atmospheric pressure atmosphere in the irradiation chamber, and takes out the electron beam into the irradiation chamber through the irradiation port foil 47. Therefore, the irradiation port foil 47 provided at the boundary between the electron beam generating unit 41 and the irradiation chamber 42 has no pinhole, has a mechanical strength that can sufficiently maintain the vacuum atmosphere in the electron beam generating unit, and easily transmits the electron beam. It is desirable. Therefore, the irradiation port foil 47 is preferably made of a metal having a small specific gravity and a small thickness, and usually aluminum or titanium foil is used.

  The processing conditions by the electron beam are determined by the acceleration voltage and the dose. The acceleration voltage affects the thickness of the cured region, and the condition of the acceleration voltage used in the present invention is preferably 40 kV or more and 300 kV or less in the low energy region. If it is 40 kV or more, it is possible to obtain a sufficient thickness of the cured region for obtaining the effects of the present invention. Moreover, it can suppress especially that an electron beam irradiation apparatus enlarges and apparatus cost increases by setting it as 300 kV or less. A more preferable acceleration voltage condition is 60 kV or more and 150 kV or less.

The dose of electron beam in electron beam irradiation is defined by the following formula (2).
D = (K · I) / V (2)

  Here, D is a dose (kGy), K is an apparatus constant, I is an electron current (mA), and V is a processing speed (m / min). The device constant K is a constant representing the efficiency of each device, and is an index of device performance. The apparatus constant K can be obtained by measuring the dose while changing the electron current and the processing speed under the condition of a constant acceleration voltage. The dose of the electron beam is obtained by attaching a dose measurement film on the roller surface, treating it with an electron beam irradiation device, and then measuring the measurement film (trade name: FWT-60, manufactured by FarWest Technology) as a film dosimeter (trade name). : FWT-92D type, manufactured by FarWest Technology).

  If it is 30 kGy or more, sufficient curing of the elastic layer and co-crosslinking of the vulcanized rubber layer and the spherical resin particles are performed to obtain the effects of the present invention. The surface hardness can be easily obtained. Moreover, by setting it as 3000 kV or less, it can suppress especially the increase in manufacturing cost by an electron beam irradiation apparatus enlarging or processing time increasing. More preferable electron dose conditions are 200 kGy or more and 2000 kGy or less.

  The charging roller according to the present invention is obtained through the above steps (1-1) to (1-3).

  The 2nd aspect of the manufacturing method of the charging member which concerns on this invention has the following process (2-1)-(2-4).

(2-1) A step of forming an unvulcanized rubber layer containing an unvulcanized rubber having an unsaturated bond on a conductive support;
(2-2) At least one resin selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin on the surface of the unvulcanized rubber layer. A step of burying a part of the spherical resin particles by press-contacting the resulting spherical resin particles;
(2-3) a step of vulcanizing an unvulcanized rubber layer in which part of the spherical resin particles are buried;
(2-4) A step of irradiating the surface of the vulcanized rubber layer with an electron beam to cure the surface.

Each step will be described below.
(Step 2-1)
An unvulcanized rubber composition is prepared by the same method except that specific spherical resin particles are not added to the mixture, and an unvulcanized rubber roller having an unvulcanized layer is prepared.

(Process 2-2)
On the surface of the unvulcanized rubber layer of the unvulcanized rubber roller obtained in (2-1), phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, acrylic resin A spherical resin particle made of at least one resin selected from the above is pressed and a part of the spherical resin particle is buried.

  Although there is no particular limitation on the method of burying a part by pressing spherical resin particles on the surface of the unvulcanized rubber layer, the following methods (a) to (c) can be mentioned.

  (A) First, spherical resin particles are dispersed in a liquid by ultrasonic waves or the like. Next, the spherical resin particle dispersion is applied to the unvulcanized rubber layer. Subsequently, the cylindrical metal and the unvulcanized rubber layer coated with the spherical resin particles are pressed against each other while rotating, and a part of the spherical resin particles is buried.

  (B) First, spherical resin particles are spread on a metal sheet having grooves having a depth of about half the average particle diameter of the spherical resin particles. A rubber blade is slid on the sheet, and the spherical resin particles not in the groove are scraped off. On this sheet, an unvulcanized rubber roller is rolled while being pressed, and a part of the spherical resin particles is buried.

  (C) First, spherical resin particles are included in the pores of a sponge roller having communication holes. The sponge roller and the unvulcanized rubber roller are rotated while being in contact with each other, and the spherical resin particles are adhered to the surface of the unvulcanized rubber layer. Subsequently, the cylindrical metal and the unvulcanized rubber layer to which the spherical resin particles are adhered are pressed while rotating, and a part of the spherical resin particles is buried.

(2-3)
A roller having an unvulcanized rubber layer in which part of the spherical resin particles are buried is heated to vulcanize the rubber to obtain a vulcanized rubber roller having a vulcanized rubber layer in which part of the spherical resin particles are buried.

(2-4)
Similarly to (Step 1-3) according to the first aspect, the surface of the vulcanized rubber layer obtained by the above step (2-3) in which a part of the spherical resin particles is buried is irradiated with an electron beam. Then, an elastic layer having a hardened region on the surface is formed.

  The charging roller according to the present invention is obtained through the steps (2-1) to (2-4).

  The present invention will be described in more detail with reference to the following examples, but these examples do not limit the present invention. In the following, unless otherwise specified, commercially available high-purity products were used for those not specified as reagents. In each example, a charging roller was produced.

  First, spherical resin particles-1 to 10 and spherical inorganic particles-1 described in Table 1 were prepared.

(Preparation of unvulcanized rubber composition No. 1 for forming an elastic layer)
The materials shown in Table 2 below were mixed to obtain an A-kneaded rubber composition. As the mixer, a 6-liter pressure kneader (product name: TD6-15MDX, manufactured by Toshin Co., Ltd.) was used. The mixing conditions were a filling rate of 70 vol%, a blade rotation speed of 30 rpm, and 16 minutes.

  Subsequently, said A kneaded rubber composition and the material shown in Table 3 were mixed. As the mixer, an open roll having a roll diameter of 12 inches (0.30 m) was used. The mixing conditions were a front roll rotation speed of 8 rpm and a rear roll rotation speed of 10 rpm, and after turning left and right a total of 20 times with a roll gap of 2 mm, thinning was performed 10 times with a roll gap of 0.5 mm. Thus, the unvulcanized rubber composition No. 1 was obtained.

  Furthermore, the unvulcanized rubber composition No. obtained above. 1, spherical resin particles No. 1 110 parts by mass were added and mixed. As the mixer, an open roll having a roll diameter of 12 inches (0.30 m) was used. The mixing conditions were a front roll rotation speed of 8 rpm and a rear roll rotation speed of 10 rpm, and after turning left and right a total of 20 times with a roll gap of 2 mm, thinning was performed 10 times with a roll gap of 0.5 mm.

(Preparation of unvulcanized rubber compositions No. 2 to No. 5 for forming an elastic layer)
Except for the composition described in Table 4 below, unvulcanized rubber composition No. In the same manner as in No. 1, the unvulcanized rubber composition No. 2-No. 5 was prepared.

  Table 5 shows the trade names and manufacturing companies of the raw materials in Table 4.

[Example 1]
(Molding of vulcanized rubber layer)
In order to obtain a metal core having an adhesive layer for adhering the vulcanized rubber layer, it is conductive at a central portion 222 mm in the axial direction of a cylindrical conductive metal core (steel, surface is nickel-plated) having a diameter of 6 mm and a length of 244 mm. A vulcanized adhesive (trade name: METALOC U-20; manufactured by Toyo Chemical Laboratory) was applied. Then, it dried for 30 minutes at the temperature of 80 degreeC.

  Next, using an extrusion molding apparatus using a crosshead, the spherical resin particle No. No. 1 to which unvulcanized rubber composition No. 1 was added. 1 and the metal core were extruded simultaneously at the same time. At that time, an extruder having a cylinder diameter of 45 mm and an L / D of 20 was used as the extruder, and the temperature was adjusted to a head of 90 ° C., a cylinder of 90 ° C., and a screw of 90 ° C.

  Thereafter, the unvulcanized rubber composition layer was vulcanized by heating in an electric furnace at a temperature of 160 ° C. for 40 minutes to obtain a vulcanized rubber layer. Both ends of the vulcanized rubber layer were cut and the axial length was 226 mm. Subsequently, the surface of the vulcanized rubber layer was polished with a plunge cut polishing machine to obtain a crown shape with an end diameter of 8.35 mm and a center diameter of 8.50 mm. Thus, a vulcanized rubber roller having a vulcanized rubber layer in which part of the spherical resin particles was exposed was obtained.

  From (Preparation of unvulcanized rubber composition for elastic layer) to (Molding of vulcanized rubber layer) in Example 1 above is referred to as Production Method-1.

(Electron beam irradiation of the vulcanized rubber layer after polishing)
The surface of the obtained vulcanized rubber roller after polishing was irradiated with an electron beam to obtain a charging roller having a cured region on the surface of the elastic layer. For the electron beam irradiation, an electron beam irradiation apparatus (manufactured by Iwasaki Electric Co., Ltd.) having a maximum acceleration voltage of 150 kV and a maximum electron current of 40 mA was used, and nitrogen was filled during irradiation. The electron beam irradiation conditions were acceleration voltage: 150 kV, electron current: 35 mA, treatment speed: 1 m / min, and oxygen concentration: 100 ppm. At this time, the apparatus constant of the electron beam irradiation apparatus at an acceleration voltage of 150 kV was 37.8, and the dose calculated from the equation (2) was 1323 kGy.

(Measurement of thickness of cured area)
The thickness of the cured region of the elastic layer was measured with a universal hardness meter. The measuring instrument was an ultra-micro hardness meter (trade name: H-100V, manufactured by Fischer), and the indenter was a square pyramidal diamond. The indentation speed was the condition of the following formula (3).
dF / dt = 1000 mN / 240 s (3)
In the above formula (3), F represents force and t represents time.
The thickness of the cured region obtained by taking the difference between before and after irradiation with the electron beam was 90 μm.

(Measurement of surface roughness)
The ten-point average roughness Rz of the elastic layer surface was measured. The measuring instrument was a surface roughness measuring instrument (trade name: Surfcoder SE3400, manufactured by Kosaka Laboratory), and the probe was a diamond contact needle having a tip radius of 2 μm. The measurement was based on JIS B0601: 1982, the measurement speed was 0.5 mm / s, the cut-off frequency λc was 0.8 mm, the reference length was 0.8 mm, and the evaluation length was 8.0 mm. As the Rz value of the charging roller, a total of 6 points of 3 points in the axial direction × 2 points in the circumferential direction were measured per charging roller, and an average value of these 6 points was used. As a result, Rz was 9 μm.

(Evaluation 1) Evaluation of charging uniformity A laser beam printer (trade name: LaserJet P1005, manufactured by Hewlett-Packard, for A4 paper longitudinal output, using an elastic blade as a cleaning member) was prepared as an electrophotographic apparatus used for evaluation. The charging roller produced above was incorporated into the process cartridge for the laser beam printer, and loaded into the laser beam printer. In an environment where the temperature is 23 ° C. and the relative humidity is 50%, after outputting one electrophotographic image, the electrophotographic image forming process is stopped, and the intermittent image forming process is restarted after 10 seconds to repeat 1000 sheets. An endurance test was conducted to output an electrophotographic image. The image output at this time is a ruled line image in which a 118-dot margin is repeated after a 2-dot horizontal line.

Next, a halftone image (an image in which a line having a width of 1 dot of laser exposure was drawn at intervals of 2 dots) and a solid image (an image in which toner was developed at the maximum density for all dots) were output one by one. The obtained halftone image and solid image after the durability test were evaluated according to the following criteria.
A: Density unevenness due to charging unevenness is not observed in both the solid image and the halftone image.
B: Minor density unevenness due to charging unevenness is observed only in the halftone image.
C: Charge unevenness is observed in the halftone image, and slight density unevenness due to the charge unevenness is recognized in the solid image.
D: Clear density unevenness due to charging unevenness is observed in both the solid image and the halftone image.
As a result, the charging uniformity of the charging roller of Example 1 was evaluated as A.

(Evaluation 2) Evaluation of presence / absence of image unevenness due to defective cleaning For the 1000 ruled line images output in the above durability test, the presence / absence and level of image unevenness due to defective cleaning of the photosensitive member were visually observed. The evaluation was based on the following criteria.
A: No prints with image unevenness due to poor cleaning are observed.
B: The number of prints in which extremely slight image unevenness due to poor cleaning occurs is 1 or more and less than 100.
C: The number of prints with clear image unevenness due to poor cleaning is 1 or more and less than 100.
D: The number of prints with clear image unevenness due to poor cleaning is 100 or more.
As a result, the evaluation of the presence or absence of image unevenness due to defective cleaning of the charging roller of Example 1 was A evaluation.

(Evaluation 3) Evaluation of Dropping of Spherical Particles by Cleaning the Charging Roller In order to evaluate how much the spherical particles existing on the surface of the elastic layer are dropped by cleaning, the spherical particles before and after cleaning were counted. First, with a digital microscope (trade name: VHX-100, manufactured by Keyence Corporation), the surface of the charging roller used in (Evaluation 2) was observed in a field of view of 500 μm × 500 μm, and 100 spherical particles were selected in advance. .

  Subsequently, the charging roller used in (Evaluation 2) was cleaned by the cleaning apparatus shown in FIG. 5 to remove dirt such as toner, external additives, and paper dust adhered to the surface. The nonwoven fabric 51 impregnated with ethanol is wound up while being pulled from roll to roll at a speed of 10 mm / second, and the charging roller 52 is rotated at a rotation speed of 500 rpm, and a load of 5 kg on one end is applied to the core metal portion at both ends. And washed for 10 seconds.

  With respect to the charging roller after washing, the same visual field observed before washing was observed again, and the remaining spherical particles were counted out of 100 spherical particles selected in advance. When the number of remaining spherical particles was calculated as the residual rate, it was 82%.

(Evaluation 4) Evaluation 2 of presence / absence of image unevenness due to poor cleaning 2
The washed charging roller was assembled in a new process cartridge and loaded into the laser beam printer. Further, the same durability test as in (Evaluation 2) was performed, and the presence or absence of image unevenness due to poor cleaning of the photoconductor and the degree thereof were visually observed for 1000 ruled line images, and (Evaluation 2) Evaluation was made according to the same criteria.

  As a result, the evaluation of the presence / absence of image unevenness due to defective cleaning when the charging roller of Example 1 was reused was A evaluation.

(Evaluation 5) Evaluation of frictional force between the photosensitive member and the elastic blade With the elastic blade in contact with the surface of the photosensitive member of the laser printer used in the above (Evaluation 2) and (Evaluation 4) The torque of the photosensitive member shaft due to the frictional force between the photosensitive member and the elastic blade was measured.

  By this measurement, it is possible to know whether or not the toner adheres to the surface of the photoreceptor due to the charging roller, and the degree thereof.

  As a measurement method, first, the unit portion in which the photosensitive member and the elastic blade were incorporated was taken out from the process cartridge from the laser printer.

  A motor connected with a torque meter (trade name: TP-10KCE manufactured by Kyowa Denki Co., Ltd.) is connected to the drive unit of the photoconductor, and the photoconductor is rotated at a rotational speed of 85 rpm with the motor. Torque was measured with a torque meter. The average value of the measured values for the first rotation of the fourth rotation from the start of rotation of the photosensitive member was used as the torque value in this embodiment.

  As a result, the torque of the photosensitive member of the laser beam printer using the charging roller of Example 1 is 0.119 N · m when the charging roller is new (Evaluation 2), and the charging roller is a reuse product (Evaluation 4). Then, it was 0.123 N · m.

[Examples 2-7, Comparative Examples 1-6]
The charging rollers of Examples 2 to 7 and Comparative Examples 1 to 6 were prepared in the same manner as in Example 1 except that the combination of the unvulcanized rubber composition and the spherical particles and the production conditions were changed as shown in Table 6. And evaluated.

  Table 7 shows the evaluation results of the charging rollers according to Examples 1 to 7 and Comparative Examples 1 to 6.

Example 8
(Formation of unvulcanized rubber layer)
A cored bar having an adhesive layer was obtained in the same manner as in Example 1.

  Next, the unvulcanized rubber composition No. 1 and the core metal having the adhesive layer were simultaneously and coaxially extruded using an extrusion molding apparatus using a cross head. At that time, the unvulcanized rubber composition No. While keeping the speed at which 1 is extruded, changing the feed speed of the core, a crown-shaped unvulcanized rubber layer with an end diameter of 8.35 mm and a center diameter of 8.50 mm is formed around the core did. At that time, an extruder having a cylinder diameter of 45 mm (Φ45) and an L / D of 20 was used as the extruder, and the temperature was adjusted to a head of 90 ° C., a cylinder of 90 ° C., and a screw of 90 ° C. Next, both end portions in the width direction of the unvulcanized rubber layer were cut, and the length of the unvulcanized rubber layer in the axial direction was set to 226 mm to obtain an unvulcanized rubber roller.

(Process of burying spherical particles)
Spherical resin particle No. The above-mentioned unvulcanized rubber layer was mixed with 0.1% by mass aqueous dispersion of No. 1 and dispersed with an ultrasonic cleaner. The unvulcanized rubber roller was immersed in the spherical resin particle dispersion, and then the unvulcanized rubber roller was pulled up at a speed of 50 mm / second. Then, it air-dried and water was evaporated and the spherical resin particle was carry | supported on the surface of the unvulcanized rubber layer.

  Next, an unvulcanized rubber roller having spherical resin particles carried on its surface was pressed against a metal cylinder having a diameter of 24 mm rotating at 30 rpm while rotating. At this time, a load of 1 kg at one end was applied to the cored bar portions at both ends of the unvulcanized rubber roller. In this way, part of the spherical resin particles was buried in the surface of the unvulcanized rubber layer. Thereafter, the unvulcanized rubber layer was vulcanized by heating in an electric furnace at a temperature of 160 ° C. for 40 minutes to obtain a vulcanized rubber layer.

  From (Formation of unvulcanized rubber layer) to (Step of burying spherical particles) in Example 8 above is referred to as Production Method-2.

  Then, the charging roller of Example 8 was obtained by irradiating with an electron beam in the same manner as in Example 1. The physical properties of the charging roller were measured and evaluated in the same manner as in Example 1.

[Examples 9 to 19 and Comparative Examples 7 to 11]
The charging rollers of Examples 9 to 19 and Comparative Examples 7 to 11 were produced in the same manner as in Example 1 except that the combination of the unvulcanized rubber composition and the spherical particles and the production conditions were changed as shown in Table 8. And evaluated.

  Table 9 shows the evaluation results of the charging rollers of Examples 9 to 19 and Comparative Examples 7 to 11.

  From Tables 6 to 9, it contains at least one spherical resin particle selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin. The surface is roughened, the surface of the elastic layer is cured by electron beam irradiation, and at least some of the spherical resin particles described above are partially exposed on the surface of the elastic layer. In addition, it is supported by the region of the elastic layer cured by electron beam irradiation, and the specific spherical resin particles and the rubber layer having an unsaturated bond are co-crosslinked by electron beam irradiation. In the charging member No. 19, the charging uniformity was evaluated as A to B. B evaluation, was A~B also evaluated at the time of reuse.

  On the other hand, in Comparative Examples 1 and 7, since spherical particles were not present on the elastic layer surface, the contact area between the elastic layer and the photosensitive member was large, and the image rank of poor cleaning was D rank.

  In Comparative Example 2, since the spherical resin particles are made of acrylic resin, the particles are scraped, and the spherical resin particles exposed on the surface become flat when the roller surface is polished, resulting in a large contact area between the elastic layer and the photoreceptor. Thus, the image rank of poor cleaning was C evaluation.

  In Comparative Examples 3, 4, 8, and 9, since the spherical particles were made of PTFE and silica, there was almost no co-crosslinking with the rubber layer having an unsaturated bond, and many spherical particles dropped off during reuse. Therefore, the image rank of defective cleaning at the time of reuse was C evaluation.

  In Comparative Examples 5 and 10, since the raw rubber of the unvulcanized rubber composition is EPM, there is no unsaturated bond, there is almost no co-crosslinking with the spherical resin particles, and many spherical resin particles dropped off during reuse. The image rank of poor cleaning was C evaluation.

  Since Comparative Examples 6 and 11 were not irradiated with an electron beam, the spherical resin particles were buried in the vulcanized rubber layer when the photoconductor and spherical resin particles were in contact with each other. It was. Moreover, since the electron beam was not irradiated, the adhesiveness of the elastic layer surface was high, and the rank of the charge uniformity due to the charging roller contamination was D evaluation.

11 Spherical Resin Particles 12 Region of Elastic Layer Cured by Electron Beam 13 Region of Elastic Layer Not Cured by Electron Beam

Claims (12)

A conductive support and an elastic layer as a surface layer, and the elastic layer has a region hardened by electron beam irradiation on the surface, and the hardened region contains spherical resin particles. A method for producing a charging member that is supported on the surface of the elastic layer and is roughened by the surface,
(1-1) A rubber containing spherical resin particles made of at least one resin selected from a phenol resin, a polyacrylonitrile resin, a nylon resin, and a polypropylene resin and an unvulcanized rubber having an unsaturated bond on the support. Curing the composition to form a vulcanized rubber layer;
(1-2) polishing the surface of the vulcanized rubber layer to expose a part of the spherical resin particles;
(1-3) The elastic layer is formed by irradiating the surface of the vulcanized rubber layer, in which part of the spherical resin particles are exposed, obtained by the step (1-2) with an electron beam to cure the surface. And a process of
The manufacturing method of the charging member characterized by including. A conductive support and an elastic layer as a surface layer, and the elastic layer has a region hardened by electron beam irradiation on the surface, and the hardened region contains spherical resin particles. A method for producing a charging member that is supported on the surface of the elastic layer and is roughened by the surface,
(2-1) forming an unvulcanized rubber layer containing an unvulcanized rubber having an unsaturated bond on the support;
(2-2) At least one resin selected from phenol resin, silicone resin, polyacrylonitrile resin, polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, polypropylene resin, and acrylic resin on the surface of the unvulcanized rubber layer. A step of burying a part of the spherical resin particles by press-contacting the resulting spherical resin particles;
(2-3) Vulcanized rubber obtained by vulcanizing the unvulcanized rubber layer in which part of the spherical resin particles are buried, obtained by the step (2-2), and in which part of the spherical resin particles are buried. Forming a layer;
(2-4) The surface of the vulcanized rubber layer obtained by the step (2-3), in which a part of the spherical resin particles are buried, is irradiated with an electron beam to cure the surface and form the elastic layer. And a process of
The manufacturing method of the charging member characterized by including.   The method for manufacturing a charging member according to claim 1, wherein the unvulcanized rubber having an unsaturated bond is at least one selected from NBR, SBR, GECO, and EPDM.   The charging member according to any one of claims 1 to 3, wherein the spherical resin particles are spherical resin particles containing at least one resin selected from polystyrene resin, polyurethane resin, nylon resin, polyethylene resin, and polypropylene resin. Manufacturing method.   The method for producing a charging member according to any one of claims 1 to 4, wherein the spherical resin particles have a shape factor SF-1 of 100 or more and 160 or less.   The method for producing a charging member according to claim 1, wherein the spherical resin particles have a length average particle diameter of 2 μm or more and 80 μm or less.   The method for producing a charging member according to claim 6, wherein the spherical resin particles have a length average particle diameter of 5 μm or more and 40 μm or less.   The charging according to any one of claims 1 to 7, wherein the elastic layer is a single layer and is the only elastic layer, and the thickness of the elastic layer is 0.8 mm or more and 4.0 mm or less. Manufacturing method of member.   The method for manufacturing a charging member according to claim 8, wherein the elastic layer has a thickness of 1.2 mm to 3.0 mm.   The method for manufacturing a charging member according to any one of claims 1 to 9, wherein a thickness of a cured region in the elastic layer is 0.5 times or more a length average particle diameter of the spherical resin particles.   The method for manufacturing a charging member according to claim 10, wherein the thickness of the cured region in the elastic layer is not less than the length average particle diameter of the spherical resin particles and not more than 200 μm. The method for producing a charging member according to claim 1, wherein the charging member has a ten-point average roughness (Rzjis) of 3 μm or more and 20 μm or less.

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