JP2007171826A - Conductive member for electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive member for an electrophotographic device, which has uniform electric characteristics to have a sufficient charging capability and has a low resistance so as to be applicable to a high-speed electrophotographic device and has uniform electric characteristics even after being used for a long period and is superior in resistance stability and is capable of suppressing pollution of an image carrying member like a photoreceptor. <P>SOLUTION: The conductive member for an electrophotographic device includes a conductive support member and a coating layer formed on the outside of the conductive support member, and the coating layer includes composite particles having metallic particles stuck to surfaces of inorganic oxide particles, and a resistance value Y of the conductive member to a voltage of 50 to 200V is within a range satisfying an expression (1): Y(Ω)=A*e(Bx) wherein 0<A<1.0E+10, -0.0001≥B≥-0.010, and 50≥x(V)≥200 are satisfied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive member for an electrophotographic apparatus used for a developing member, a charging member, a transfer member and the like provided in the electrophotographic apparatus.

  In image forming apparatuses such as electrophotographic apparatuses such as copying machines and optical printers and electrostatic recording apparatuses, corona discharge apparatuses have been conventionally used as means for charging an image carrier surface such as a photosensitive member or a dielectric. However, the corona discharge device is effective as means for uniformly charging the surface of a photoconductor such as an image carrier to a predetermined potential, but requires an expensive high-voltage power supply. In addition to the increase in size of the apparatus, corona products such as ozone are often generated during discharge, and the surface of the charged body may be destroyed due to abnormal discharge.

  In recent years, a contact charging method has been adopted for such a corona discharge device. In the contact charging method, a charged member surface is charged by bringing a charging member to which a voltage is applied close to or in contact with the surface of the photoreceptor. In the contact charging method, there are advantages such as less generation of corona products such as ozone, less destruction of the surface of the object to be charged due to abnormal discharge, simple structure, low cost and downsizing of the apparatus. . In the contact charging method, a rubber roller type charging member in which a semiconductive elastic coating layer is formed on a conductive support such as a metal core is used.

The coating layer made of an elastic body of the charging member needs to have an appropriate semiconductivity in order to prevent leakage caused by pinholes or scratches on the surface of a charged body such as a photoreceptor. Further, in order to uniformly charge the photosensitive member, it is preferable that the electric resistance value of the charging member is uniform semiconductivity having a volume resistivity of about 1 × 10 ³ to 1 × 10 ⁹ Ω · cm. In order to impart such electrical characteristics to the elastic layer, an elastic layer is produced using an electronic conductive rubber composition that is semiconductive by blending conductive particles such as carbon black.

In such an electronic conductive rubber composition, the electric resistance can be adjusted by the amount of conductive particles such as carbon black blended in the raw rubber. However, in the semiconductive region having a volume resistivity of 1 × 10 ³ to 1 × 10 ⁹ Ω · cm, the electrical resistance may change greatly due to a slight change in the blending amount of the conductive particles. It is difficult to produce an elastic body layer that exhibits a uniform desired electric resistance value in such a semiconductive region, and the electronic conductive rubber composition causes variations in electric resistance within and between charging members. It becomes a factor of.

  A rubber composition with uniform electrical resistance, such as epichlorohydrin rubber, NBR, or the like, a polar rubber composition that itself has semiconductivity, or an ion conductive system that imparts semiconductivity by adding an ionic conductive agent to raw rubber Rubber compositions are known.

  On the other hand, the charging member is also required not to contaminate an image carrier such as a photoreceptor. In the contact charging method, the charging member is used in contact with the photoconductor, etc., so that, for a long period of use, low molecular components such as ionic conductive agent and softening agent in the charging member are deposited and contaminate the photoconductor. As a result, a functional failure may occur in the photosensitive member, and an image defect may occur.

  As a method for suppressing photoconductor contamination due to low molecular components, there is an example in which a layered organic silicate or a porous filler is mixed in a rubber material used for a charging member. (For example, refer to Patent Documents 1 and 2).

Furthermore, there are examples in which the contamination of the photoconductor is reduced by using an ionic liquid having low volatility among ionic conductive agents or using an ionic conductive agent having a high affinity with a polymer. (For example, refer to Patent Documents 3 and 4).
JP 2003-223038 A JP 2001-109233 A JP 2003-202722 A JP 2004-272209 A

  An object of the present invention is to have uniform electrical characteristics, sufficient charging ability, low resistance applicable to high-speed electrophotographic apparatus, uniform electrical characteristics even after long-term use, and resistance stability. Another object of the present invention is to provide a conductive member for an electrophotographic apparatus that is excellent in that it can suppress contamination of an image bearing member such as a photoreceptor.

  The inventors of the present invention have studied the reduction in resistance of charging members and the like in order to stably charge the electrophotographic photosensitive member under the demand for further speeding up the image forming process in the electrophotographic apparatus. In a charging member having a coating layer using an ionic liquid or an ionic conductive agent (hereinafter collectively referred to as an ionic conductive agent), the amount of addition of the ionic conductive agent or the like in the coating layer is increased. As a result, the resistance of the charging member or the like can be reduced. However, as the amount of the ionic conductive agent added increases, the amount of the ionic conductive agent deposited from the coating layer also increases. In addition to the above problem, it has been found that there is a problem caused by a large amount of the ionic conductive agent in the coating layer. A problem caused by a large amount of the ionic conductive agent or the like in the coating layer can be that uneven distribution of the ionic conductive agent or the like occurs with time in the coating layer. It has been found that uneven distribution of the ionic conductive agent or the like causes non-uniformity in the resistance value of the charging member, which may change the charging ability over time. As a result of intensive studies, the coating layer includes composite particles in which metal particles adhere to the surface of the inorganic oxide particles, and has a resistance value in a specific range with respect to a voltage of 50 to 200 V, which occurs with time. It has been found that precipitation and uneven distribution of ionic conductive agent and the like in the coating layer can be suppressed. As a result, the charging member has a low resistance applicable to a high-speed electrophotographic apparatus, can obtain resistance stability even after long-term use, suppresses contamination of the photoreceptor, and performs stable charging. Based on this knowledge, the present invention has been completed.

That is, the present invention has an electroconductive support and a coating layer formed on the outside thereof, and the coating layer contains composite particles in which metal particles adhere to the surface of inorganic oxide particles. A conductive member having a resistance value Y of a formula (1) with respect to a voltage of 50 to 200V
Y (Ω) = A · e (Bx) (1)
For an electrophotographic apparatus characterized by satisfying the following conditions (where 0 <A <1.0E + 10, −0.0001 ≧ B ≧ −0.010, 50 ≦ x (V) ≦ 200). The present invention relates to a conductive member.

  The conductive member for an electrophotographic apparatus of the present invention has uniform electric characteristics, sufficient charging ability, low resistance applicable to a high-speed electrophotographic apparatus, and uniform electric characteristics even in long-term use. It has excellent resistance stability and can suppress contamination of an image bearing member such as a photoreceptor.

The electroconductive member for an electrophotographic apparatus of the present invention has a conductive support and a coating layer formed on the outside thereof, and the coating layer comprises composite particles in which metal particles adhere to the surface of inorganic oxide particles. It is the electroconductive member for electrophotographic apparatuses to contain. And the resistance is the expression (1) with respect to the voltage at 50 to 200V
Y (Ω) = A · e (Bx) (1)
(Where, 0 <A <1.0E + 10, −0.0001 ≧ B ≧ −0.010, and 50 ≦ x (V) ≦ 200).

  The conductive support provided on the conductive member for an electrophotographic apparatus of the present invention may have any shape such as a roller shape or a blade shape. Any material can be used as long as it is made of metal, and examples thereof include SUS and aluminum.

  The coating layer provided on the conductive member for an electrophotographic apparatus of the present invention contains composite particles in which metal particles adhere to the surface of inorganic oxide particles.

  The metal particles in the composite particles may be any metal as long as they are made of metal, but preferably contain one or more of gold, platinum, silver, cobalt, and copper. The average particle size is preferably 1 to 20 nm. When the average particle diameter is within this range, a desired amount of metal particles can be easily attached to the surface of inorganic oxide particles having a particle diameter described later.

  Here, as the average particle diameter, an image of 50 arbitrary composite particles can be captured by a scanning electron microscope or a transmission electron microscope, and the average particle diameter can be calculated by image analysis. For the sample, the coating layer is cut using a microtome (or cryomicrotome), and when the surface is observed with a scanning electron microscope, the surface is formed, and when the surface is observed with a transmission electron microscope, an ultrathin section having a thickness of about 50 nm is prepared. . The particle size of other particles used in the present invention can also be measured by the same measurement method.

  In addition, the inorganic oxide particles in the composite particles may be any material as long as the material is an inorganic oxide, but it is preferable to include one or more of tin oxide, aluminum oxide, and titanium oxide. The particle size is preferably 20 nm to 1 μm. If the particle size is 20 nm or more, a desired amount of metal particles having the above particle size can be uniformly and easily attached to the surface. If the particle size is 1 μm or less, it can be easily and uniformly dispersed in the coating layer.

Furthermore, in order to obtain composite particles in which the metal particles are uniformly attached to the surface of the inorganic oxide particles, when the particle size of the metal particles is d and the particle size of the inorganic oxide particles is D, the formula (2)
D / 1000 <d <D / 10 (2)
It is preferable to satisfy the relationship. In the composite particles, the metal particles and the inorganic oxide particles have a particle diameter satisfying this relationship, whereby the conductivity in the coating layer can be improved.

  The mass ratio of the metal particles to the inorganic oxide particles in the composite particles is preferably 5 to 90% by mass with respect to the inorganic oxide. If the mass of the metal particles relative to the inorganic oxide in the composite particles is 5% by mass or more, the composite particles have desired conductivity, and if the mass is 90% by mass or less, the composite particles can be easily dispersed uniformly in the coating layer. it can.

  The content of the particles in which the metal particles adhere to the inorganic oxide particles is not particularly limited, but is blended at a ratio of 0.5 to 25 parts by mass with respect to 100 parts by mass of the binder contained in the coating layer. It is preferable to do. If the amount is 0.5 parts by mass or more, the conductivity is improved, and if it is 25 parts by mass or less, a decrease in conductivity can be suppressed.

  In such composite particles, cations such as hydronium ions in the binder contained in the coating layer are coordinated with the hydroxyl groups on the surface of the metal particles. Resistance can be realized. Composite particles rarely move in the binder like ionic conductive agents and ionic liquids, and the conductivity of the conductive member is stable, suppressing migration to the surface and contamination of the photoreceptor, etc. It is possible to suppress non-uniform conductivity of the conductive member accompanying use of the apparatus.

  As an example of the composite particle, as shown in the schematic diagram of FIG. 1, the metal particle 5a attached to the surface of the inorganic oxide particle 5b can be shown.

  The coating layer in the electroconductive member for an electrophotographic apparatus of the present invention preferably contains a resin that serves as a binder for dispersing the composite particles. Although any resin can be used as the binder, it is preferable to use an ion conductive resin having a uniform electric resistance. Examples of the ion conductive resin include ethylene oxide-propylene oxide-allyl glycidyl ether copolymer, epichlorohydrin homopolymer (CHC), epichlorohydrin-ethylene oxide copolymer (CHR), epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer. Examples include coal (CHR-AGE), acrylonitrile-butadiene copolymer (NBR), hydrogenated acrylonitrile-butadiene copolymer (H-NBR), acrylic rubber (ACM, ANM), and urethane rubber (U). Can do. These can be used alone or in combination of two or more.

The volume resistivity of such a coating layer is 1 × 10 ³ to 1 × 10 ⁹ Ω · cm in the case of a charging member to which a photoconductor is applied, so that it can be used in a high-speed electrophotographic apparatus. preferable.

  Furthermore, the coating layer may be a filler, a softening agent, a processing aid, a crosslinking aid, or a crosslinking accelerator that is generally used as an additive for the binder resin, if necessary, within a range that does not impair the function of the composite particles. Agents, crosslinking accelerators, crosslinking retarders, tackifiers, dispersants, foaming agents, and the like. Moreover, the said ionic conductive agent, an electronic conductive agent, etc. may be contained.

  As a method for preparing the coating layer, a composite particle and a binder resin raw material, if necessary, the additive is used as a closed mixer such as a Banbury mixer or a pressure kneader, or an open mixer such as an open roll. And a method of curing by heating and the like.

  The coating layer may have a single-layer structure or a multilayer structure having two or more layers having various functions. In the case of a multilayer structure, the composite particles may be contained in any layer or in all layers. In addition, as necessary, it contains oxides such as carbon black, graphite, titanium oxide and tin oxide, ionic conductive agents such as copper and silver, electronic conductive agents, etc. as necessary. It may be.

  Further, as the outermost layer in contact with the photoreceptor or the like of the coating layer, a non-adhesive treatment layer that has been subjected to a non-adhesion treatment may be provided for the purpose of preventing adhesion of toner and external additives. Non-adhesive treatment includes methods of irradiating energy rays such as electron beams, ultraviolet rays, X-rays and microwaves to cure the surface to make it non-sticky, acrylic resin, polyurethane, polyamide, polyester, polyolefin, silicone resin, etc. It is preferable to use a non-adhesive resin or a silicone-based reactive surface treatment agent.

In such a conductive member for an electrophotographic apparatus of the present invention, the voltage dependency Y of resistance at 50 to 200 V is represented by the formula (1).
Y (Ω) = A · e (Bx) (1)
(Where 0 <A <1.0E + 10, −0.0001 ≧ B ≧ −0.010, and 50 ≦ x (V) ≦ 200). In the electrophotographic apparatus, the electroconductive member has a voltage dependency in a range where the resistance value Y satisfies the formula (1) with respect to a voltage of 50 to 200 V, thereby suppressing the contamination of the photoreceptor. Durability is high and charging ability can be stabilized. In order to obtain a conductive member for an electrophotographic apparatus having such voltage dependency, the composite particles may be contained in the above range in the coating layer.

  Here, the resistance value of the electroconductive member for an electrophotographic apparatus of the present invention can be a value measured using an electrical resistance measuring apparatus schematically shown in FIG. Specifically, the rubber roller 4a, which is the subject, is pressed against the cylindrical aluminum drum 41 by pressing means (not shown) at both ends of the metal core 11, and is rotated following the rotation of the aluminum drum. In this state, a direct current voltage, for example, 100 V or the like is applied to the metal core portion of the rubber roller using the power source 42, and the electric resistance of the charging roller is obtained from the voltage loaded on the resistor 43 connected in series to the aluminum drum. be able to. The electrical resistance was measured at a temperature of 23.5 ° C./humidity of 60% R.D. H. It can be performed in an environment (also described as N / N).

  As an example of the electroconductive member for an electrophotographic apparatus of the present invention, the one shown in the schematic view of FIG. 3 can be exemplified. As the electroconductive member for an electrophotographic apparatus of the present invention, for example, as shown in FIG. 3A, a monolayer structure comprising a cored bar 11 as a conductive support and a coating layer 12 provided on the outer periphery thereof. Even so, as shown in FIG. 3B, the coating layer may have a multilayer structure of two or more layers.

  The electrophotographic apparatus to which the electroconductive apparatus for electrophotographic apparatus of the present invention is applied may be any one of a copying machine, a laser beam printer, an LED printer, an electrophotographic plate making system, and the like. In addition, a process cartridge that is integrated with the image forming apparatus, the photosensitive member, and the like and is detachable from the main body of the electrophotographic apparatus can be used. Specific examples of the member in the electrophotographic apparatus to which the electroconductive member for an electrophotographic apparatus of the present invention is applied include a charging member that contacts the photoreceptor and charges the photoreceptor. In addition, the electrostatic latent image formed on the photosensitive member or the like is developed with toner attached thereto, and the developing member for forming the toner image or the toner image formed on the surface of the photosensitive member or the like is transferred to a transfer material. Examples thereof include a transfer member.

  An example of an electrophotographic apparatus to which the electrophotographic apparatus conductive member of the present invention is applied is the electrophotographic apparatus shown in the schematic configuration diagram of FIG. The electrophotographic apparatus shown in FIG. 4 is provided with an electrophotographic photosensitive member 21 as a member to be charged. The electrophotographic photosensitive member 21 has a drum shape having a basic support layer composed of a conductive support 21b such as aluminum and a photosensitive layer 21a formed on the support 21b. Alternatively, it may be rotationally driven at a predetermined peripheral speed.

  A charging roller 1, which is a conductive member of the present invention, is installed so as to be in contact with the electrophotographic photosensitive member 21 (primary charging) with a predetermined polarity and potential. The charging roller 1 includes a core metal 11 that is a conductive support, an elastic layer 12 formed on the core metal 11, and a coating layer having a surface layer 13 formed on the elastic layer 12. Both end portions of 11 are pivotally attached, and are driven to rotate as the electrophotographic photosensitive member 21 rotates.

  Such a charging roller 1 is charged by applying a predetermined direct current (DC) bias or a direct current and alternating current (DC + AC) bias to the metal core 11 by a rubbing power source 23a connected to the power source 23, and comes into contact therewith. The rotating electrophotographic photosensitive member 21 is charged to a predetermined polarity and potential. The electrophotographic photosensitive member whose peripheral surface is uniformly charged by contact rotation with the charging roller is then subjected to exposure of target image information (laser beam scanning exposure, slit exposure of a document image, etc.) by the exposure means 24, and the periphery thereof. An electrostatic latent image corresponding to target image information is formed on the surface.

  Next, toner is supplied to the electrostatic latent image formed on the photoconductor in the developing device 25, and a visible image is sequentially formed as a toner image. Next, the toner image on the electrophotographic photosensitive member 21 is moved to the transfer roller side by the transfer roller 26 charged to a polarity opposite to that of the toner. At this time, the transfer material 27 is conveyed from the transfer material supply means (not shown) to the nip portion between the electrophotographic photosensitive member 21 and the transfer roller 26 at an appropriate timing in synchronism with the rotation of the electrophotographic photosensitive member 21 and transferred. A toner image is transferred onto the material 27.

  The transfer material 27 onto which the toner image has been transferred is separated from the electrophotographic photosensitive member and conveyed to a fixing unit (not shown), and the toner image is fixed by a fixing unit such as heating and output as an image formed product. Alternatively, in an electrophotographic apparatus that forms an image on the back surface, the image is re-conveyed to the image forming apparatus.

  The peripheral surface of the electrophotographic photosensitive member 21 after the toner image is transferred is subjected to pre-exposure by the pre-exposure device 28, and residual charges on the photosensitive drum are removed (static elimination). In the pre-exposure means 28, for example, an LED chip array, a fuse lamp, a halogen lamp, a fluorescent lamp, or the like can be used. Considering the charge eliminating effect, it can be said that the exposure amount in the pre-exposure means is preferably larger than the exposure amount of the exposure means described above. Further, the position of the pre-exposure means can be appropriately selected and provided between a cleaning member and a charging device described later.

  The cleaned peripheral surface of the electrophotographic photosensitive member 21 is cleaned by a cleaning member 29 to remove adhering contaminants such as toner remaining on the surface without being transferred, and used for the next image formation.

  The charging roller 1 may be driven and rotated by the electrophotographic photosensitive member 21 as described above. However, the charging roller 1 is fixed without rotating, or forward or reverse with respect to the rotation direction of the electrophotographic photosensitive member 21. It may be used in a state of being driven and rotated with a predetermined peripheral speed in the direction.

  When the electrophotographic apparatus is used as a copying machine, the exposure is performed by reflecting or transmitting light from a document, or converting a document into a read signal, scanning a laser beam based on this signal, driving an LED array, Alternatively, it may be performed by driving a liquid crystal shutter array.

  The conductive member for an electrophotographic apparatus of the present invention can be used as a developing member, a transfer member, a charge eliminating member, and a conveying member such as a paper feed roller, in addition to the charging member such as the charging roller.

  As a process cartridge for an electrophotographic apparatus to which the charging member for an electrophotographic apparatus of the present invention is applied, for example, a plurality of elements provided in the electrophotographic apparatus such as an electrophotographic photosensitive member, a charging member, a developing device, a cleaning member, One that is integrally incorporated can be mentioned. Specifically, as shown in FIG. 5, a process cartridge in which the charging roller 1, the photosensitive member 21, the developing device 25, the cleaning member 29 and the like as the conductive member for the electrophotographic apparatus of the present invention are integrated is illustrated. can do. Such a process cartridge is preferably configured to be detachable using guide means such as a rail of the electrophotographic apparatus main body.

  Hereinafter, the electroconductive member for an electrophotographic apparatus of the present invention will be described in detail, but the technical scope of the present invention is not limited thereto.

Hereinafter, unless otherwise specified, “parts” means “parts by mass”, and commercially available high-purity products were used as reagents and the like unless otherwise specified.
[Example 1]
[Production of conductive member]
As raw material rubber, 50 parts of epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (trade name: Epichromer CG105, manufactured by Daiso Corporation) and epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (product) Name: Epichromer ON301, manufactured by Daiso Co., Ltd.) 50 parts, Zinc stearate as processing aid, 1 part of zinc stearate as vulcanization accelerator, MT carbon black as filler (trade name: Therma Macs Flow) 35 parts of Form N990, manufactured by CANCAB, and 5 parts of calcined clay (trade name: ST-KE, manufactured by Shiraishi Calcium Co., Ltd.), the metal particles having an average particle diameter of 2 nm as particles adhered to the inorganic oxide Ag, inorganic oxide particles are Al ₂ O ₃ having an average particle size of 100nm metal containing 2 parts of composite particles (trade name: Nanocera Metal, manufactured by Ningbo Lingji Surface Process Co., Ltd.), dibenzothiazolyl disulfide (trade name: Noxeller DM, Ouchi Shinko Chemical Industries, Ltd.) 1 part), tetramethylthioram disulfide (trade name: Noxeller TS, manufactured by Ouchi Shinko Chemical Co., Ltd.) 1 part, and 1.2 parts of sulfur are mixed in an open roll and unvulcanized. A rubber composition was obtained.

  The obtained unvulcanized rubber composition was extruded into a tube shape by a vent type rubber extruder (caliber 50 mm vent extruder L / D = 16, manufactured by EM Giken Co., Ltd.), and 30 ° C. at 160 ° C. with pressurized steam using a vulcanized can. The rubber tube having an outer diameter of 15 mm, an inner diameter of 5.5 mm, and a length of 250 mm was obtained.

  Next, a conductive hot melt adhesive was applied to the central portion 232 mm in the axial direction of a cylindrical surface of a cylindrical conductive core (steel, surface is nickel plated) having a diameter of 6 mm and a length of 256 mm. The rubber tube described above was press-fitted into what was dried for 2 minutes, followed by secondary vulcanization and adhesion treatment at 160 ° C. for 2 hours in a hot air oven. Cut both ends of the rubber of the vulcanized roller to make the length of the rubber part 232 mm, and then polish the rubber part with a rotating grindstone to obtain a crown shape with an end diameter of 8.40 mm and a central part diameter of 8.5 mm. A coating layer was obtained.

Next, the surface treatment was performed by irradiating the surface of the coating layer with ultraviolet rays. In the surface treatment, while rotating the roller, the surface was irradiated with an ultraviolet intensity of 40 mW / cm ² for 10 minutes using an ultraviolet irradiation device (185 nm and 245 nm were the wavelength main components) to prepare a charging roller.
[Electrical resistance of conductive members]
The electrical resistance of the obtained charging roller was measured at a temperature of 23.5 ° C./humidity of 60% R.D. H. Under the environment (also referred to as N / N), the electrical resistance was determined by applying a voltage of DC 100V between the cored bar and the metal drum using the electrical resistance measuring device of FIG. 10 ⁶ Ω. As a result of measuring the resistance at x = 50 to 200 V, the volume resistance Y (= A · e (Bx)) as voltage dependency was A = 3.0E + 07 and B = −0.0031.
[Evaluation of charging ability of conductive members]
This charging roller was incorporated into the process cartridge shown in FIG. 5, and image evaluation was performed with an electrophotographic apparatus (Laser Shot LBP-2510, manufactured by Canon Inc.). In the image evaluation, only the DC voltage is applied to the core metal of the charging roller so that the surface potential of the photosensitive member becomes −600 V in the N / N environment so that the difference in charging ability by the charging roller is most noticeable. Applied. Further, evaluation was performed by forming a halftone image in which one dot was printed with a comma pattern without operating the pre-exposure means.

  The image evaluation was ranked according to the state of occurrence of a horizontal black streak-like image defect in a halftone image that occurs when charging ability is insufficient. Rank 1 is good (no black streak-like image defects are observed at all), and rank 2 is a level that fine black streak-like image defects can be confirmed on the entire surface of the image. The image rank of this example is rank 1 Met.

Next, 10,000 sheets were passed and the durability test was performed. As a result, the image rank after passing was also 1.
[Evaluation of Contamination of Conductive Member Photoconductor]
Further, the cartridge was placed at 40 ° C./95% R.D. H. After being left for 30 days in this environment, it was once again incorporated into an electrophotographic apparatus, halftone images were formed in an N / N environment, and image evaluation was performed after leaving in a harsh environment. As a result, the transfer of contaminants from the charging roller to the photoreceptor was not confirmed, and an image with good quality was obtained.
[Example 2]
A charging roller was prepared in the same manner as in Example 1 except that 2.5 parts of the composite particles were used. In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electrical resistance under N / N environment is 7.62 × 10 ⁶ Ω, and the volume resistance Y (= A · e (Bx)) as voltage dependence is A = 3.0E + 07, B = −0.0025 there were. The image evaluation in charging ability was rank 1. The evaluation of the image after paper passing was rank 1, and no migration of contaminants from the charging roller to the photoconductor was confirmed even after leaving in a harsh environment.
[Example 3]
A charging roller was produced in the same manner as in Example 1 except that 5.0 parts of the composite particles were used. In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electric resistance under N / N environment is 8.57 × 10 ⁶ Ω, and volume resistance Y (= A · e (Bx)) as voltage dependency is A = 4.0E + 07, B = −0.0022 there were. The image evaluation in charging ability was rank 1. The evaluation of the image after paper passing was rank 1, and no migration of contaminants from the charging roller to the photoconductor was confirmed even after leaving in a harsh environment.
[Example 4]
A charging roller was produced in the same manner as in Example 1 except that 10 parts of the composite particles were used. In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electrical resistance in the N / N environment is 9.37 × 10 ⁶ Ω, and the volume resistance Y (= A · e (Bx)) as voltage dependence is A = 4.0E + 07, B = −0.0026 there were. The image evaluation in charging ability was rank 1. The evaluation of the image after paper passing was rank 1, and no migration of contaminants from the charging roller to the photoconductor was confirmed even after leaving in a harsh environment.
[Example 5]
A charging roller was produced in the same manner as in Example 1 except that 30 parts of the composite particles were used. In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electric resistance under the N / N environment is 1.09 × 10 ⁸ Ω, and the volume resistance Y (= A · e (Bx)) as voltage dependence is A = 6.0E + 07, B = −0.0050 there were. Although no transfer of contaminants from the charging roller to the photoconductor was confirmed even after being left in a harsh environment, the image evaluation in charging ability was ranked 2 because of insufficient charging due to high resistance.
[Comparative Example 1]
The metal particles used as the composite particles are adhered to the inorganic oxide, the metal particles are Ag having an average particle diameter of 2 nm, the inorganic oxide particles are Al ₂ O ₃ having an average particle diameter of 100 nm, and the metal content is 30 wt% (product) Name: Nanocera Metal, manufactured by Ningbo Lingji Surface Process Co., Ltd., China 2) Example 1 except that 2 parts of Adeka Sizer-LV-70 (Asahi Denka Co., Ltd.) were used as the ion conductive agent. In the same manner, a charging roller was produced.

  In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electric resistance in the N / N environment is 5.03 × 10 ⁶ Ω, and the volume resistance Y (= A · e (Bx)) as voltage dependency is A = 2.0E + 07, B = −0.0025 there were. The image evaluation in terms of charging ability was rank 1, and the image evaluation after passing paper was rank 1, but the transfer of contaminants from the charging roller to the photoconductor was observed even after being left in a harsh environment.
[Comparative Example 2]
The metal particles used as the composite particles are adhered to the inorganic oxide, the metal particles are Ag having an average particle diameter of 2 nm, the inorganic oxide particles are Al ₂ O ₃ having an average particle diameter of 100 nm, and the metal content is 30 wt% (product) Name: Nanocera Metal, manufactured by Ningbo Lingji Surface Process Co., Ltd., China 2 parts, EC600JD (Lion Corporation) 8 parts and HS500 (Asahi Carbon Co., Ltd.) 14 parts are used as conductive agents. A charging roller was produced in the same manner as in Example 1 except for the above.

  In the same manner as in Example 1, the electrical resistance of the charging roller and the volume resistance as voltage dependency were measured to evaluate the charging ability and the contamination of the photoreceptor.

The electrical resistance in the N / N environment is 3.18 × 10 ⁴ Ω, and the volume resistance Y (= A · e (Bx)) as voltage dependence is A = 2.0E + 05, B = −0.012. there were. Image evaluation in terms of charging ability was rank 1, and although no contaminants were transferred from the charging roller to the photoconductor even after being left in a harsh environment, the image evaluation after passing paper was ranked 2 because of the effect of resistance fluctuation due to voltage fluctuation. It became.

  As is apparent from the results, the electroconductive member for an electrophotographic apparatus of the present invention has a sufficiently low electric resistance. Therefore, in a high-speed electrophotographic apparatus using the electroconductive apparatus, a halftone image can be output in an N / N environment. The quality of the image and the image after 10,000 sheets is good and excellent in durability. Even when left for a long time in a harsh environment due to contact with the photoconductor, it is caused by the transferred substance from the conductive member. Photoconductor contamination is suppressed and a high quality image is obtained.

It is a schematic diagram which shows an example of the composite particle contained in the electroconductive member for electrophotographic apparatuses of this invention. It is a schematic block diagram which shows an example of the apparatus which measures the electrical resistance of the electroconductive member for electrophotographic apparatuses of this invention. It is a typical sectional view showing an example of a conductive member for electrophotographic devices of the present invention. It is a schematic block diagram which shows an example of the electrophotographic apparatus to which the electroconductive member for electrophotographic apparatuses of this invention is applied. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an electrophotographic apparatus to which a conductive member for an electrophotographic apparatus of the present invention is applied.

Explanation of symbols

1 Charging roller (conductive member for electrophotographic equipment)
11 Core (conductive support)
12 Covering layer 13 Covering layer 21 Image carrier (photoreceptor)
21a photosensitive layer 21b support 21c support shaft 23 power supply 23a rubbing power supply 24 exposure means 25 developing device 26 transfer roller 27 transfer material 28 pre-exposure means 29 cleaning member 41 aluminum drum 42 external power supply 43 reference resistance 4a rubber roller T toner 5a metal Particle 5b Inorganic oxide particle

Claims (7)

A conductive member for an electrophotographic apparatus having a conductive support and a coating layer formed on the outside thereof, wherein the coating layer contains composite particles in which metal particles adhere to the surface of inorganic oxide particles. A conductive member for an electrophotographic apparatus, wherein the resistance value Y is in a range satisfying the formula (1) with respect to a voltage of 50 to 200V.
Y (Ω) = A · e (Bx) (1)
(In the formula, 0 <A <1.0E + 10, −0.0001 ≧ B ≧ −0.010, 50 ≦ x (V) ≦ 200 is satisfied)   The conductive member for an electrophotographic apparatus according to claim 1, wherein the coating layer contains 0.5 to 25 parts by mass of the composite particles with respect to 100 parts by mass of the binder.   The electroconductive member for an electrophotographic apparatus according to claim 1, wherein the composite particles contain inorganic oxide particles having a particle diameter of 20 nm to 1 μm.   The electroconductive member for an electrophotographic apparatus according to any one of claims 1 to 3, wherein the composite particles contain metal particles having a particle diameter of 1 to 20 nm. As composite particles, when the particle size of the inorganic oxide is D and the particle size of the metal particles is d, the formula (2)
D / 1000 <d <D / 10 (2)
5. The electroconductive member for an electrophotographic apparatus according to claim 1, wherein:   The electroconductive member for an electrophotographic apparatus according to any one of claims 1 to 5, wherein the composite particles contain 5 to 90 mass% of metal particles with respect to the inorganic oxide particles. The metal particles include one or more of gold, platinum, silver, cobalt, and copper, and the inorganic oxide particles include one or more of tin oxide, aluminum oxide, and titanium oxide. The electroconductive member for an electrophotographic apparatus according to any one of claims 1 to 6.

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