JP4713900B2 - Manufacturing method of conductive member and conductive member for electrophotography - Google Patents

Description

  The present invention relates to a method for producing a conductive member, and in particular, a charging member, a developer carrying member, a transfer member, a cleaning member, and a charge removing member used in an image forming apparatus employing an electrophotographic system such as a printer, a facsimile machine, and a copying machine. The present invention relates to a method for producing a conductive member for electrically controlling an object to be contacted such as an electrophotographic conductive member.

  An image forming apparatus that employs an electrophotographic system, that is, an electrophotographic apparatus generally includes an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transferring unit.

  Further, as this charging means, a voltage (a voltage of only DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage) is applied to a charging member that is in contact with or close to the surface of the electrophotographic photosensitive member. Many systems that charge the surface of the photoreceptor are used.

  As a voltage to be applied to the charging member, when a voltage obtained by superimposing an AC voltage on a DC voltage is used, an AC power source is required, leading to an increase in size and cost of the electrophotographic apparatus, an increase in power consumption, From the above viewpoint, the voltage applied to the charging member may be only a DC voltage because the durability of the charging member and the electrophotographic photosensitive member may decrease due to the large amount of ozone generated by the use of alternating current. preferable.

  Furthermore, a contact-type charging method is preferably used from the viewpoint of stably charging, reducing the generation of ozone, or reducing the cost.

  When the voltage applied to the charging member is a DC voltage only, the charged potential of the charged object surface is likely to be uneven, and minute streak-like image defects are likely to occur, and the charging uniformity. Is difficult to obtain. In addition, there is a problem that the electrification of the charging member is deteriorated due to continuous use, the resistance of the charging member is easily increased (charged up), and the charged potential of the charged object surface is decreased accordingly. In addition, in an image forming apparatus using a contact-type charging method, there is a problem in that unevenness of image density or the like occurs due to a charging failure due to contamination (developer surface adhesion) of a charging member. In particular, in the charging method in which only a DC voltage is applied to the charging member, the influence of contamination on the charging member tends to appear as an image defect compared to a charging method in which a voltage in which an AC voltage is superimposed on the DC voltage is applied.

  To solve this problem, there is a technique for obtaining uniformity of resistance by using conductive particles having a small particle size (submicron order) for the purpose of obtaining uniformity of charging (for example, Patent Documents). 1).

  In order to control the surface property (roughness) of the member and improve the uniformity of charging, particles having an average particle size of micron order are added in order to express the desired roughness. (For example, refer to Patent Document 2). As another purpose other than improving the charging uniformity, there is a technique of adding particles having an average particle size on the order of microns for the purpose of reducing charging noise and preventing leakage due to scratches on the surface of the photoreceptor. (For example, see Patent Documents 3 and 4).

  However, particles with a small particle size (submicron order or less) have a large surface energy, so the cohesive force between the particles is strong, and secondary aggregates such as structure structures are often formed. Dispersion is not easy, micro resistance unevenness is likely to occur, and resistance uniformity is difficult to obtain.

In addition, when micron order particles are dispersed, the cohesive force between the particles is weaker than that of the particles, and the dispersion share of each particle is strong. The following surface wear and destruction result, and the desired surface properties cannot be obtained. For this reason, when the contact-type charging method is used, the surface property of the member is non-uniform, so that the charging member is liable to be unevenly distributed and a charging failure occurs.
Japanese Patent Laid-Open No. 06-250494 JP 2003-207966 A JP 09-146342 A JP-A-11-133705

  An object of the present invention is an electrophotographic apparatus to which a manufactured conductive member is applied, wherein the voltage applied to the charging member is only a DC voltage, and a film in which particles are dispersed is formed as a surface layer. Even if it is a conductive member, it is easy to disperse the particles uniformly, micro resistance unevenness does not occur, the uniformity of resistance is obtained, and the surface property of the conductive member is uniform and charged. It is an object of the present invention to provide a method for producing a conductive member and an electrophotographic conductive member capable of outputting a good image free from image defects and being less likely to cause uneven contamination of the member and causing poor charging.

The present invention has one or more coating layers on a conductive support, and at least the metal oxide conductive particles, the metal conductive particles, the carbon black, or the carbon-based coating on the surface layer of the coating layer. the average particle size is a conductive particle comprising at least one conductive particles and particles a of 1 to 500 nm, the resin, rubber or the average particle size is any one of elastomer, contains particles B of 1~50μm In the method for producing a conductive member, the surface layer of the coating layer is applied using a paint in which the particles A and the particles B are dispersed by a dispersing means, and the share when the particles B are dispersed is rather weak than share when dispersing the particles a, and that the peripheral speed of the portion highest circumferential speed at contributing sites distributed dispersing means in the step of dispersing the particles B are obtained is not more than 6 m / s Conductive member characterized by It is a manufacturing method.

  The present invention also provides an electrophotographic conductive member obtained by the above-described method for producing a conductive member.

  According to the present invention, even in the case of a conductive member formed with a film in which particles are dispersed as a surface layer, the particles can be easily dispersed uniformly, without causing microscopic resistance unevenness, and uniform resistance. In addition, the surface of the conductive member is uniform, the charging member is less likely to be unevenly distributed, the charging failure is unlikely to occur, and the conductive member can output a good image without image defects. A manufacturing method can be provided.

  FIG. 1 shows an electrophotographic apparatus using a conductive member obtained by the present invention as a contact charging member (charging roller). When a voltage is applied to the charging member, a discharge occurs in a minute space between the charging member and the photosensitive member, and the surface of the photosensitive member is charged.

  In the present invention, not only can the charging uniformity of the conductive member be improved, but also a resistance change can be suppressed, so that a very excellent image can be obtained. In particular, as shown in FIG. 1, a plurality of prints of an image forming apparatus that employs a so-called developing and cleaning (cleanerless) system that does not have an independent cleaning unit and collects toner remaining on the photoreceptor after transfer by a developing unit. It is extremely effective in making this possible.

  Although the mechanism of the present invention has not been clarified, the following has been elucidated by intensive studies by the present inventors.

  The dispersibility of the conductive agent and functional particles used as materials constituting the charging member contributes greatly to the uniformity of charging of the member. When the dispersibility of the conductive agent is inferior, the uniformity of resistance is not sufficient, so that it is difficult to obtain the uniformity of charging. In addition, current deterioration of the conductive agent is likely to occur. Similarly, when the dispersibility of the functional particles is inferior, the uniformity of the resistance of the portion constituting the conductivity of the member is impaired, so that it is difficult to obtain the uniformity of charging. Moreover, it becomes difficult to obtain uniformity in the expression of the functionality of the particles.

  When particles having an average particle diameter of 1 to 500 nm are used as the conductive agent and functional particles, the cohesive force between the particles is strong, and in order to disperse the particles up to the vicinity of the primary particle diameter, a certain share or more is required. Thus, it was found necessary to break up strong particle aggregates. Moreover, it is thought that the dispersion | distribution state of a electrically conductive agent and the contact state of electrically conductive agents are also affecting the deterioration by electricity supply. If the dispersibility of the conductive agent is improved, it is considered that the resistance does not increase even when the charging member is continuously used (continuous energization).

  When particles having an average particle diameter of 1 to 50 μm are used as the functional particles, the average particle diameter is 1 to 500 nm because the dispersion share per particle is stronger than particles having an average particle diameter of 1 to 500 nm. It was found that when the dispersion was carried out with the same share as the dispersion of the particles, the particles were worn and destroyed to the primary particle size or less due to excessive dispersion, and desired characteristics could not be obtained.

  As a result of various studies as described above, the present inventors have one or more coating layers on a conductive support to solve the problems of the present invention, and at least the surface layer of the coating layer has In a method for producing a conductive member containing particles A having an average particle diameter of 1 to 500 nm and particles B having an average particle diameter of 1 to 50 μm, a coating material in which the particles A and the particles B are dispersed by a dispersing means is used. The surface layer of the coating layer is applied, and the method of producing a conductive member is characterized in that the share when the particles B are dispersed is weaker than the share when the particles A are dispersed. Is.

(1) Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus including a process cartridge including a conductive member obtained by the present invention. The image forming apparatus of this example is a reversal developing method using transfer type electrophotography, and a developing and cleaning method (cleanerless).

  Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member as an image carrier, which is driven to rotate at a predetermined peripheral speed (process speed) in the direction of an arrow.

  Reference numeral 2 denotes a charging roller (conductive member obtained by the present invention) as a charging means for the electrophotographic photosensitive member, which is brought into contact with the electrophotographic photosensitive member 1 with a predetermined pressing force. In this example, the charging roller is driven. Then, it rotates at the same speed as the electrophotographic photosensitive member 1. A predetermined DC voltage (in this case, -1180 V) is applied to the charging roller 2 from the charging bias application power source S1, so that the surface of the electrophotographic photosensitive member 1 has a predetermined polarity potential (dark part potential -400 V). ) Is uniformly charged by a contact charging method or a DC charging method.

  Reference numeral 3 denotes exposure means, for example, a laser beam scanner. The surface L of the electrophotographic photosensitive member is set to the potential of the exposure bright portion (bright portion potential −120 V) by performing exposure L corresponding to the target image information by the exposure unit 3 on the charging processing surface of the electrophotographic photosensitive member 1. ) Is selectively lowered (attenuated) to form an electrostatic latent image.

  Reference numeral 4 denotes a reversal developing unit, which selects a toner (negative toner) that is charged (development bias of −350 V) with the same polarity as the charging polarity of the electrophotographic photosensitive member in the exposed bright portion of the electrostatic latent image of the electrophotographic photosensitive member. The electrostatic latent image is visualized as a toner image. In the figure, 4a is a developing roller, 4b is a toner supply roller, and 4c is a toner layer thickness regulating member.

  Reference numeral 5 denotes a transfer roller as transfer means, which is formed by bringing the transfer portion into contact with the electrophotographic photosensitive member 1 with a predetermined pressing force. The electrophotographic photosensitive member rotates in the forward direction with the rotation of the electrophotographic photosensitive member. It rotates at the same peripheral speed as the peripheral speed. Further, a transfer voltage having a polarity opposite to the charging polarity of the toner is applied from the transfer bias applying power source S2. The transfer material P is fed to the transfer portion from a paper feed mechanism portion (not shown) at a predetermined control timing, and the back surface of the fed transfer material P is charged with toner by the transfer roller 5 to which a transfer voltage is applied. The toner image on the electrophotographic photosensitive member 1 is electrostatically transferred to the transfer material P at the transfer portion.

  The transfer material that has received the transfer of the toner image at the transfer portion is separated from the electrophotographic photosensitive member, introduced into a toner image fixing means (not shown), subjected to a toner image fixing process, and output as an image formed product. In the case of the double-sided image formation mode or the multiple image formation mode, this image formed product is introduced into a recirculation conveyance mechanism (not shown) and reintroduced into the transfer unit.

  Residues on the electrophotographic photosensitive member such as transfer residual toner are charged to the same polarity as the charging polarity of the electrophotographic photosensitive member by the charging roller 2. Then, the transfer residual toner reaches the developing means 4 through the exposure portion, and is electrically collected in the developing device by the back contrast, thereby achieving development and cleaning (cleanerless).

  In this example, the electrophotographic photosensitive member 1, the charging roller 2, and the developing means 4 are integrally supported, and the process cartridge 6 is detachable from the main body of the image forming apparatus. At this time, the developing means 4 may be a separate body.

(2) Conductive Member For example, the charging member has a roller shape as shown in FIG. 2, and includes a conductive support 2a and an elastic layer 2b integrally formed on the outer periphery thereof as a covering layer.

  Another structure of the charging member obtained by the present invention is shown in FIG. As shown in FIG. 3, the charging member may be a two-layer coating layer composed of an elastic layer 2b and a surface layer 2c, a three-layer layer composed of an elastic layer 2b, a resistance layer 2d and a surface layer 2c, and a resistance layer. A configuration may be adopted in which the second resistance layer 2e is provided between the layer 2d and the surface layer 2c, and four or more layers are formed on the conductive support 2a.

  As the conductive support 2a used in the present invention, a round bar made of a metal material such as iron, copper, stainless steel, aluminum and nickel can be used. Furthermore, the metal surface may be plated for the purpose of providing rust prevention and scratch resistance, but it is necessary that the conductivity is not impaired.

  In the charging roller 2, the elastic layer 2 b has appropriate conductivity and elasticity in order to supply power to the electrophotographic photosensitive member as a member to be charged and to ensure good uniform adhesion to the electrophotographic photosensitive member 1. Further, in order to ensure uniform adhesion between the charging roller 2 and the electrophotographic photosensitive member 1, the elastic layer 2b may be formed in a so-called crown shape by polishing so that the central portion is thickest and narrows toward both ends. preferable. Since the charging roller 2 that is generally used is in contact with the electrophotographic photosensitive member 1 by applying a predetermined pressing force to both ends of the support 2a, the pressing force at the central portion is small and increases toward both ends. Therefore, if the straightness of the charging roller 1 is sufficient, there is no problem, but if it is not sufficient, density unevenness may occur in the images corresponding to the central portion and both end portions. The crown shape is formed to prevent this.

The conductivity of the elastic layer 2b is a conductive agent having an electronic conductive mechanism such as carbon black, graphite and conductive metal oxide in an elastic material such as rubber, and an ionic conductive mechanism such as an alkali metal salt or a quaternary ammonium salt. It may be adjusted to less than 10 ¹⁰ Ωcm by appropriately adding a conductive agent. Specific elastic materials of the elastic layer 2b include, for example, natural rubber, ethylene propylene rubber (EPDM), styrene butadiene rubber (SBR), silicon rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR), Synthetic rubbers such as nitrile butadiene rubber (NBR) and chloroprene rubber (CR), and also polyamide resins, polyurethane resins, silicone resins and the like.

In a charging member that applies a direct current voltage only to charge an object to be charged, in order to achieve charging uniformity, particularly a moderate resistance polar rubber (for example, epichlorohydrin rubber, NBR, CR, urethane rubber, etc.) It is preferable to use polyurethane resin as an elastic material. These polar rubbers and polyurethane resins are considered to have a slight conductivity due to moisture and impurities in the rubber and resin as carriers, and these conduction mechanisms are considered to be ionic conduction. However, when an elastic layer is prepared without adding a conductive agent to these polar rubbers and polyurethane resins, the obtained charging member has a high resistance value in a low temperature and low humidity environment (L / L) and is 10 ¹⁰ Ωcm or more. In some cases, a high voltage must be applied to the charging member.

Therefore, it is preferable to adjust the conductive member having the above-described electronic conductive mechanism and the conductive agent having the ionic conductive mechanism by appropriately adding so that the resistance value of the charging member is less than 10 ¹⁰ Ωcm in the L / L environment. However, the conductive agent having an ionic conduction mechanism has a small effect of lowering the resistance value, and particularly in the L / L environment. Therefore, the resistance adjustment may be performed by supplementarily adding a conductive agent having an electronic conductive mechanism in addition to the addition of a conductive agent having an ionic conductive mechanism.

  The elastic layer 2b may be a foam obtained by foaming these elastic materials.

  The surface layer 2c constitutes the surface of the charging member, and is not preferable in a material configuration that contaminates the photoconductor because it contacts the photoconductor that is the object to be charged. Moreover, it can be said that the thing with surface releasability is preferable. Therefore, it can be said that it is preferable to use a resin as the surface layer material.

  As the binder resin material for the surface layer 2c for exhibiting the characteristics of the present invention, fluororesin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene-butylene-olefin copolymer (SEBC) And olefin-ethylene / butylene-olefin copolymer (CEBC). As the material for the surface layer in the present invention, fluorine resin, acrylic resin, silicone resin and the like are particularly preferable.

  For the purpose of reducing the static friction coefficient to these binder resins, solid lubricants such as graphite, mica, molybdenum disulfide and fluororesin powder, or fluorosurfactants, wax, silicone oil, etc. may be added. Good.

  Various conductive particles are appropriately used for the surface layer 2c. Examples of the conductive particles include metal oxide-based conductive particles, metal-based conductive particles, carbon black, and carbon-based conductive particles. In the present invention, in order to obtain a desired electric resistance, Two or more kinds of the various conductive particles may be used in combination.

  Examples of the metal oxide conductive particles include zinc oxide, tin oxide, indium oxide, titanium oxide (such as titanium dioxide and titanium monoxide), iron oxide, and aluminum oxide. Some of the metal oxide-based conductive particles show sufficient conductivity by themselves, but some of them do not. In order to make the conductivity of the particles sufficient, a dopant may be added to these particles. In general, it is considered that surplus electrons are generated due to the presence of metal oxide lattice defects and show conductivity, and formation of lattice defects is promoted by addition of a dopant, and sufficient conductivity can be obtained. For example, aluminum is used as a dopant for zinc oxide, antimony is used as a dopant for tin oxide, and tin is used as a dopant for indium oxide. Moreover, when obtaining the electroconductivity of titanium oxide, what coated electroconductive tin oxide on titanium oxide etc. can be mentioned. Furthermore, what coated the carbon black on the silica etc. are mentioned.

  Examples of the metal conductive particles include silver, copper, nickel, and zinc.

  Examples of carbon black include acetylene black, furnace black, and channel black.

  Examples of the carbon conductive particles include graphite, carbon fiber, activated carbon, charcoal and the like.

  The average particle size of the conductive particles is preferably less than 1.0 μm. If the average particle size exceeds 1.0 μm, pinhole leakage is likely to occur when pinholes exist on the photosensitive drum, which is not preferable. On the other hand, when the specific gravity of the conductive particles is heavy, if the average particle diameter exceeds 1.0 μm, the dispersion stability of the paint is deteriorated, and it tends to settle in the paint.

  The particles A having an average particle diameter of 1 to 500 nm in the present invention are preferably used in order to obtain resistance uniformity and charging uniformity.

The average particle diameter of the particles of 1 to 50 [mu] m B of the present invention, particles of high-molecular compounds, for example, polyamide resin, silicone resin, (meth) acrylic resins, styrene resins, phenol resins, polyester resins, melamine resins, urethane resins , Resin particles such as olefin resin, epoxy resin, and copolymers, modified products and derivatives thereof, ethylene-propylene-diene copolymer (EPDM), styrene-butadiene copolymer rubber (SBR), silicone rubber, Rubber particles such as urethane rubber, isoprene rubber (IR), butyl rubber, acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), epichlorohydrin rubber, polyolefin thermoplastic elastomer, urethane thermoplastic elastomer, polystyrene heat Plasticity Sutoma, Po Riesuteru based thermoplastic elastomer, polyamide thermoplastic elastomer, a polybutadiene based thermoplastic elastomer, ethylene vinyl acetate type thermoplastic elastomers, polyvinyl chloride thermoplastic elastomer, a thermoplastic elastomer particles, such as chlorinated polyethylene-based thermoplastic elastomer Is mentioned.

  These particles may be used alone or in combination of two or more, and may be subjected to surface treatment, modification, introduction of functional groups or molecular chains, coating, and the like.

  Among these, the particle B in the present invention is mainly used for controlling surface properties, and resin particles that are easy to control the average particle size, particle size distribution, and shape depending on production conditions and the like and that can easily obtain uniform particles are preferably used. It is done.

The resistance value of the surface layer is preferably 10 ⁴ to 10 ¹⁵ Ωcm. Moreover, it is preferable that thickness is 1-500 micrometers. In particular, it is preferably 1 to 50 μm.

  The elastic coating layer and the resistance layer may be formed by, for example, adhering or coating a sheet-shaped or tube-shaped layer formed in advance to a predetermined film thickness, or electrostatic spray coating or dipping coating. You may carry out by the apply | coating methods. Moreover, after forming a layer roughly by extrusion molding, the method of adjusting the shape of a layer by grinding | polishing etc. may be used, and the method of hardening and shaping | molding material to a predetermined shape within a type | mold may be used.

  When the layer is formed by a coating method, the solvent used in the coating solution may be any solvent that can dissolve the binder material, for example, alcohols such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, Ketones such as cyclohexanone, amides such as N, N-dimethylformamide and N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether, and methyl acetate Esters such as ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, ethylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, benzene, toluene, xylene, ligroin, chlorobenzene, di Chlorobenzene and aromatic compounds such as.

  As a method for dispersing the particles in the surface layer material, conventionally known solution dispersing means such as a ball mill, a sand mill, a paint shaker, a dyno mill and a pearl mill can be used by mixing the solvent, the surface layer material and the particles. In the present invention, among these dispersers, it is preferable to use a bead mill in which the step of dispersing particles can be continuously performed, the dispersion share is appropriate, and the share can be easily changed.

(3) Electrophotographic photoreceptor The electrophotographic photoreceptor used with the conductive member obtained in the present invention is not particularly limited.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
A charging roller as a charging member obtained in the present invention was produced in the following manner.

Epichlorohydrin rubber 100 parts by mass Quaternary ammonium salt 2 parts by mass Calcium carbonate 90 parts by mass Zinc oxide 5 parts by mass Fatty acid 5 parts by mass

  After kneading the above materials for 10 minutes with a closed mixer adjusted to 60 ° C., 15 parts by mass of an ether ester plasticizer is added to 100 parts by mass of epichlorohydrin rubber, and further cooled for 20 minutes with a closed mixer cooled to 20 ° C. The raw material compound was prepared by kneading. To this compound, 100 parts by mass of epichlorohydrin rubber as a raw rubber, 1 part by mass of sulfur as a vulcanizing agent, 1 part by mass of noxeller DM (dibenzothiazyl sulfide) as a vulcanization accelerator, and noxeller TS (tetramethylthiuram monosulfide) 0.5 parts by mass was added and kneaded for 10 minutes by a two-roll mill cooled to 20 ° C. The resulting compound was molded by an extruder so as to form a roller around a φ6 mm stainless steel support, heated and steam vulcanized, and then polished to an outer diameter of φ12 mm to obtain an elastic layer. . The roller length was 230 mm.

Subsequently, the following acrylic polyol solution (PLACCEL DC2016 manufactured by Daicel Chemical Industries)
100 parts by mass isocyanate A (IPDI) (VESTANAT B1370 manufactured by Degussa)
22 parts by mass isocyanate B (HDI) (DURANATE TPA-B80E manufactured by Asahi Kasei Chemicals Corporation) 34 parts by mass conductive particles (corresponding to particle A) (CS-Bk100Y average particle size: 20 nm manufactured by Toda Kogyo Co., Ltd.) 14 parts by mass titanium oxide ( SMT-150IB manufactured by Teika Co., Ltd. 18 parts by mass modified dimethyl silicone oil (SH28PA manufactured by Toray Dow Corning Silicone Co., Ltd.) 0.2 parts by mass Methyl isobutyl ketone 220 parts by mass was stirred using a mixer to prepare a mixed solution. Next, this mixed solution was mixed with a bead mill disperser (Ultra Visco Mill manufactured by IMEX Co., Ltd.) filled with glass beads having an average particle diameter of 0.8 mm as a medium at a filling rate of 80% with respect to the volume of the vessel. Circulation was carried out for 21 hours at a speed of 8 m / s and a processing speed of 600 ml / min for dispersion treatment.

Furthermore, PMMA particles (corresponding to particle B) (Techpolymer MBX-5 manufactured by Sekisui Plastics Co., Ltd., average particle size: 3 μm) 30 parts by mass of methyl isobutyl ketone 13 parts by mass using a mixer Was put into the previous dispersion, the disk peripheral speed was changed to 6 m / s, and dispersion treatment was performed for 2 hours to obtain a dispersion solution.

  This dispersion solution was applied by a dipping method to form a surface layer having a film thickness of 10 μm to obtain a roller-shaped charging member.

"Evaluation of surface properties of charging roller"
The surface of the charging roller was observed with an electron microscope, and the shape of the particle B was confirmed to be cracked or chipped. The results are shown in Table 1.

"Durability test for continuous multiple image output when only DC voltage is applied to the charging roller"
The charging roller obtained above is attached to the electrophotographic image forming apparatus shown in FIG. 1, and in an L / L environment (temperature of 15 ° C./humidity of 10%), an A4 image of 15000 continuous images with a printing rate of 4% The halftone images were printed every 500 sheets, and image evaluation was visually performed for the occurrence of image defects due to the increase in resistance of the charging roller. The results are shown in Table 2. However, in the initial stage of the image output durability test, the applied voltage (DC voltage only) was set in each environment so that the dark portion potential Vd of the electrophotographic photoreceptor was in the vicinity of the image output durability test.

  A in the table indicates that the obtained image is very good, B is good, C indicates that the halftone image has slightly uneven density, and D indicates that the halftone image has uneven density and unevenness in density.

  Further, the resistance of the charging roller was measured by a method as shown in FIG. 4 before (initially) starting the image printing endurance test and immediately after printing 15000 continuous images. The results are shown in Table 2. In the figure, 2 is a charging roller, 11 is a cylindrical electrode made of stainless steel, 12 is a resistor, and 13 is a recorder. The pressing force between them is the same as that of the image forming apparatus used, and the resistance value when -200 V is applied from the external power source S3 is measured.

(Example 2)
A charging member was produced in the same manner as in Example 1 except that the disk peripheral speed during dispersion of the conductive particles was 10 m / s.

  The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

(Example 3)
A charging member was produced in the same manner as in Example 1 except that the disk peripheral speed during dispersion of PMMA particles (corresponding to particle B) was 4 m / s.

  The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

(Comparative Example 1)
A charging member was prepared in the same manner as in Example 1 except that the disk peripheral speed during dispersion of PMMA particles (corresponding to particle B) was 8 m / s.

  The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

(Comparative Example 2)
A charging member was produced in the same manner as in Example 1 except that the disk peripheral speed during dispersion of the conductive particles (corresponding to the particles A) was 6 m / s.

  The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

(Comparative Example 3)
A charging member was produced in the same manner as in Comparative Example 1 except that the disk peripheral speed during dispersion of the conductive particles (corresponding to the particles A) was 6 m / s.

  The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

It is a schematic block diagram of the image forming apparatus provided with the process cartridge provided with the electroconductive member obtained by this invention. It is the schematic which shows an example of a structure of the charging roller obtained by this invention. It is the schematic which shows the example of the other structure of the charging roller obtained by this invention. It is the schematic of the resistance measuring apparatus of a charging roller.

Explanation of symbols

1; Image carrier (electrophotographic photosensitive member)
2; Charging member (charging roller)
2a; conductive support 2b; elastic layer 2c; surface layer 2d; resistive layer 2e; second resistive layer 3; image exposing means 4; developing means 4a; developing roller 4b; toner supply roller 4c; 5; Transfer means (transfer roller)
6; process cartridges S1, S2, S3; bias application power supply L; exposure P; transfer material 11; cylindrical electrode (metal roller)
12; Fixed resistor 13; Recorder

Claims (7)

One or more coating layers are provided on the conductive support, and at least the metal oxide conductive particles, metal conductive particles, carbon black, or carbon conductive particles are formed on the surface layer of the coating layer . Conductive particles containing at least one kind of conductive particles containing particles A having an average particle diameter of 1 to 500 nm and any one of resin, rubber or elastomer and particles B having an average particle diameter of 1 to 50 μm In the production method, the surface layer of the coating layer is applied using a paint in which the particles A and the particles B are dispersed by a dispersing means, and the share when the particles B are dispersed rather weak than share at the time of dispersion, and the peripheral speed of the portion highest circumferential speed at contributing sites distributed dispersing means in the step of dispersing the particles B are obtained is equal to or less than 6 m / s Method for manufacturing conductive member Method for manufacturing a conductive member according to 請 Motomeko 1 peripheral speed of the portion highest circumferential speed is obtained by contributing sites dispersed Ru der than 7m / s dispersing means in the step of dispersing said particles A. The method for producing a conductive member according to claim 1 or 2 , wherein the dispersing means in the step of dispersing the particles A and the dispersing means in the step of dispersing the particles B are performed by the same disperser. Method for manufacturing a conductive member according to any one of process and particles B Cormorant continuously line the step of dispersing the 請 Motomeko 1-3 to disperse the particles A. Method for manufacturing a conductive member according to any one of Ah Ru請 Motomeko 1-4 in the dispersion means Gabi Zumiru. Claim 1-5 electrophotographic conductive member, characterized in that obtained by the production method of the conductive member according to any one of. Electro-conductive member for electrophotography according to 請 Motomeko 6 Ru Ah at the charging roller.

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