Abstract: An electrophotographic member including an electro-conductive substrate, an elastic layer, and a surface layer, the surface layer containing a fine particle and a binder resin, and having a thickness of less than 1.0 ?m, the fine particles having an average particle diameter of from 0.1 ?m to 0.9 ?m, the fine particles having a volume occupancy of 60 vol % to 99 vol % with respect to 100 vol % of the binder resin in the surface layer, the elastic modulus E1 of the fine particle being 1,000 MPa or more, and the elastic modulus E2 of the binder resin being 2 MPa to 200 MPa, and MD-1 hardness H1 of the surface layer being 50° to 100°, and a difference (H1?H2) between the H1 and MD-1 hardness H2 of the elastic layer being 5° or more.

Abstract: A developing roll has a metal core, an elastic layer, and a surface layer. A value X is 65.6 N/mm3 or more and a value Y is 229 ?m or more. The value X is P1/(D1×A)?P2/(D2×A). P1 is the load to displace the roll 100 ?m when a metal probe is pressed against the roll. D1 is the displacement of the roll caused by the probe under the load P1. A is the area of the probe. P2 is the load to displace a material roll by 100 ?m when the probe presses against the material roll with the core and the elastic layer and without the surface layer. D2 is the displacement of the material roll caused by the probe under the load P2. The value Y is the displacement of the roll when the probe pierces the surface layer.

Abstract: A developing roll used in an electrophotographic image forming apparatus has a metal core member, an elastic layer made of a rubber disposed around the core member, and a surface layer disposed around the elastic layer. The texture aspect ratio of the surface Str of the surface layer is equal to or greater than 0.55.

Abstract: The purpose of the present invention is to provide a developing roller which is not prone to scumming in a nonprinting area. The solution is to provide a developing roller which has an elastic layer, a coat layer formed on the elastic layer, and end portion coat layers formed on outermost surfaces on two axial end portions, wherein the end portion coat layer contains a conductive material.

Abstract: The purpose of the present invention is to provide a developing roller which is not prone to scumming in a nonprinting area. The solution is to provide a developing roller which has an elastic layer, a coat layer formed on the elastic layer, and end portion coat layers formed on outermost surfaces on two axial end portions, wherein the end portion coat layer contains a conductive material.

Abstract: Provided is a developing device including: a toner; and a developer carrying member. The developer carrying member includes an electroconductive substrate and a surface layer on the substrate, the surface layer being a single layer and including a matrix containing a crosslinked urethane resin as a binder, wherein E1 ?200 MPa and 10 MPa?E2 ?100 MPa, where E1 is an elastic modulus of the matrix in a first region from an outer surface of the surface layer to a depth of 0.1 and E2 is an elastic modulus of the matrix in a second region from a depth of 1.0 to 1.1 ?m from the outer surface. The toner includes a toner particle containing a binder resin and a colorant and having a Martens hardness of 85 to 1,100 MPa when measured under a condition of a maximum load of 2.0×10?4 N.

Abstract: An electroconductive elastic body includes: a cross-linked product of a first ionic electro-conductive rubber, a cross-linked product of a second ionic electro-conductive rubber, and at least one of a fatty acid and a fatty acid metal salt; wherein the electroconductive elastic body has a matrix that includes the cross-linked product of the first ionic electro-conductive rubber, and a domain that includes the cross-linked product of the second ionic electro-conductive rubber; the cross-linked product of the second ionic electro-conductive rubber includes a polyether skeleton; an electrical resistance of the domain is lower than an electrical resistance of the matrix; in a waveform separation profile of the elastic body as obtained by a small-angle X-ray scattering method, A2 and A1 satisfy a relationship expressed by the following expression (1): 0.005?(A2×C2/A1×C1)?0.030??(1).

Abstract: A charging roll includes a core member, a rubber base material disposed around the core member, and a surface layer disposed around the rubber base material. The ten point height of irregularities RZ of a surface of the surface layer is equal to or greater than 3.9 micrometers, and is equal to or less than 6.1 micrometers. The mean spacing between peaks Sm of the surface of the surface layer is equal to or greater than 12.5 micrometers and is equal to or less than 13.5 micrometers.

Abstract: Provided an electrophotographic member capable of causing less fog in an H/H environment even when used in a torque-reduced image forming apparatus. The member comprises an electro-conductive substrate, an electro-conductive layer thereon and insulating parts, the member having a surface having an electrical insulating first region and an electro-conductive second region, the first region and the second region being adjacent to each other, a total area of the second region in a square region put on an outer surface of the member is 30% to 80% of an area of the square region; two or more of the 200 straight lines drawn in the square region at an interval of 5 ?m pass the second region at least once, and, the number of line segment LS having a length of 200 ?m or more is 5% or less of the total number of the line segment LS.

Abstract: A composition for forming an electroless plating undercoat comprising: (A) a conductive polymer (B) one or more resins selected from the group consisting of a polyester polyol resin and a polyether polyol resin; and (C) a polyisocyanate compound.

Abstract: A developing roller includes a base portion, an elastic layer disposed on the outer circumference of the base portion, and a coating disposed on the outer peripheral surface of the elastic layer. The ten-point mean roughness of the coating according to JIS B 0601:1994 is from 2 to 4 micrometers. Furthermore, the mean spacing of profile irregularities of the coating according to JIS B 0601:1994 is from 120 to 290 micrometers. Furthermore, the surface free energy of the coating according to the Owens-Wendt-Rabel-Kaelble method is from 5 to 25 millinewtons per meter.

Abstract: A development device includes a development housing, a development roller, a supply roller and a layer thickness regulating member. The development housing stores a nonmagnetic one-component toner. The development roller is formed by a cylindrical elastic body, and moves in a same direction as a rotational direction of a rotatable photosensitive drum at a development nip area while coming into contact with the photosensitive drum. The supply roller is formed by a cylindrical elastic body, and supplies the toner to the development roller and collects the toner from the development roller. The development roller has a surface free energy within a range of 5 mJ/m2 or more and 27 mJ/m2 or less.

Abstract: Provided is a developer carrying member that can stably form a high-quality electrophotographic image. The developer carrying member includes an electroconductive support and a surface layer in the stated order, wherein the surface layer contains a binder resin and electroconductive particles, and a content of the electroconductive particles in a region from a surface of the surface layer opposite to an outer surface thereof on a side facing the electroconductive support to a depth of 150 nm is 1% or more and 25% or less, and wherein the surface layer has a volume resistivity of 1.0×10?2 ?·cm or more and 1.0×102?·cm or less.

Abstract: An electrophotographic developing member includes an electro-conductive support and an electro-conductive layer provided on the support, wherein the electro-conductive layer has a matrix containing a first rubber and a plurality of domains dispersed in the matrix, and the domain contains a second rubber and an electronic conductive agent and when a frequency is log-log-plotted on a horizontal axis and an impedance is log-log-plotted on a vertical axis with respect to an impedance measured by applying an alternating current voltage having an amplitude of 1 V on the electro-conductive layer while changing a frequency between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, an inclination of an impedance on a high frequency side is ?0.8 or more and ?0.3 or less and an impedance on a low frequency side is 1.0×104? to 1.0×1011?.

Abstract: A toner including toner base particles each including a binder resin and a colorant, and external additive, wherein the toner satisfies conditions (a), (b), and (c) below: (a) storage elastic modulus G?(50) of the toner at 50° C. and storage elastic modulus G?(90) of the toner at 90° C. satisfy Formula (1); G?(50)/G?(90)?6.0×102??Formula (1) (b) a BET specific surface area Bt(m2/g) of the toner and a coverage Ct (%) of the toner base particles covered with the external additive satisfy Formula (2); and Bt?0.03×Ct?1.60??Formula (2) (c) the external additive includes at least cohered particles, the cohered particles are non-spherical secondary particles each formed through cohesion of primary particles, and a number average secondary particle diameter of the cohered particles is 130 nm or greater.

Abstract: Provided is an electrophotographic member in which density unevenness of an image is less likely to occur even in the case of outputting an image after standing in a high-temperature and high-humidity environment for a long period of time. The electrophotographic member includes: an electroconductive substrate; an electroconductive elastic layer on or above the substrate; and an insulating portion on the elastic layer, an outer surface of the electrophotographic member being composed of an outer surface of the insulating portion and an outer surface of the elastic layer that is not covered with the insulating portion, wherein the elastic layer contains a urethane resin as a first resin, and the elastic layer has a region from the outer surface of the elastic layer constituting the outer surface of the electrophotographic member to a depth of 1 ?m, the region further containing a second resin.

Abstract: A buffer material including a skinned polyurethane foam including a foam layer and a skin layer formed on the surface of the foam layer, wherein the skinned polyurethane foam essentially contains no silicone compound, the foam layer is polyurethane foam, the skin layer is a polyurethane resin layer produced by reaction of a skin-isocyanate component containing an aliphatic and/or an alicyclic polyisocyanate with a skin-active hydrogen group-containing component, the skin layer has a storage modulus at 23° C. (E?coat) of 1×107 Pa or more and 3×108 Pa or less, the foam layer has a storage modulus at 23° C. (E?foam) of 1×105 Pa or more and 5×106 Pa or less, and the ratio (E?coat/E?foam) of the storage modulus at 23° C. (E?coat) of the skin layer relative to the storage modulus at 23° C. (E?foam) of the foam layer is 10 or more and 500 or less.

Abstract: A developing roller that suppresses contamination of the surface of a photosensitive member and also obtains a high-quality image. The developing roller includes an electro-conductive substrate, an electro-conductive elastic layer and a surface layer which are stacked in this order, wherein the surface layer has resin particles that are dispersed in a polyurethane matrix, an outer surface of the surface layer has a first protrusion originating in first resin particle and a second protrusion originating in second resin particle, wherein the first resin particle contains polyurethane, an elastic modulus E1 of the first resin particle is 100 to 2000 MPa, an elastic modulus E2 of the second resin particle is 2 to 50 MPa, a maximum height roughness Rz of the outer surface is 6 to 18 ?m, and a peak vertex density Spd is 5.0×103 to 5.0×104(1/mm2).

Abstract: An image forming apparatus includes an image bearing member configured to bear an image and a charging roller to which a direct current voltage is applied and which is configured to charge a surface of the image bearing member. The charging roller includes a shaft member, an elastic layer formed around the shaft member, and a surface layer formed around the elastic layer. Particles having particle diameters within a range of 2 ?m or larger and 15 ?m or smaller are dispersed in the surface layer. A maximum height Sz (?m) and an autocorrelation length Sal (?m) with respected to the surface layer of the charging roller satisfy 8?Sz?16 and 13?Sal?30.

Abstract: A cartridge includes a rotatable developer carrying member rotatably supported by the frame and rotatable about an axis L1 and a coupling member rotatable about an axis L2, with the coupling member being configured to transmit a rotational force to the developer carrying member. The coupling member is movable between (a) a reference attitude in which the axis L2 of the coupling member is parallel to and offset from the axis L1 of the developer carrying member, (b) a first inclination attitude in which the coupling member is inclined in a direction toward the developer carrying member, and (c) a second inclination attitude in which the coupling member is inclined in a direction different from the direction that the coupling member is inclined in the first inclination attitude.

Abstract: An inventive charging roller (1) includes a roller body (2) which is formed of a crosslinked product of a rubber composition containing a rubber component including 30 to 70 parts by mass of GECO, 15 to 60 parts by mass of IR and not less than 1 part by mass of SBR and/or NBR based on 100 parts by mass of the overall rubber component and has an outer peripheral surface (5) finished in a finish-polished surface. An inventive production method includes the steps of: forming a roller body (2) from the crosslinked product of the rubber composition described above; and wet-polishing or mirror-polishing an outer peripheral surface (5) of the roller body (2) into a finish-polished surface.

Abstract: To provide a developing roller having improved toner conveying force in a high-temperature and high-humidity environment. The developing roller has a substrate and an electro-conductive layer on the substrate. The outer surface of the developing roller has an electrical insulating first region and an electro-conductive second region adjacent to the first region and at the same time has at least one groove in the first region.

Abstract: Provided is a developing member capable of sufficiently securing a toner conveyance amount, thereby being capable of suppressing a reduction in image density, even when a solid black image or an image having a high print percentage is continuously output. The developing member includes an electro-conductive substrate and an electro-conductive layer thereon, an outer surface of the developing member includes a first, second and third regions, when surface potentials of the respective regions with scanning probe microscope, and measured surface potential of the respective regions are defined as V1, V2, and V3, respectively, V1 is ?0.70 V to ?0.50 V, 1.30?V1/V2?25.00, and V3 is 0.00 V to 0.50 V.

Abstract: An electrophotographic electroconductive member which keeps high discharge performance even in use under a high temperature and high humidity environment is provided. The electroconductive member includes an electroconductive substrate, and a surface layer including a net-like structural body disposed on the electroconductive substrate, wherein the net-like structural body includes non-electroconductive fibers containing a radiation degradable resin.

Abstract: Provided is a developing roller comprising an electroconductive substrate and an electroconductive layer thereon, the electroconductive layer retaining resin particles so that at least a part of each of the resin particles is exposed on an outer surface of the developing roller; the outer surface of the developing roller constituted by electrically insulating domains and an electroconductive matrix, assuming that a square region 200-?m in a side is put on the outer surface of the developing roller, the square region including the domains, among the domains in the square region at least two of them satisfying specific condition, and assuming that the outer surface of the developing roller is charged, and creating a potential map of the charged outer surface of the developing member, the two domains satisfying the specific condition being ascertained in the potential map.

Abstract: An example charging member includes a conductive support, a conductive elastic body layer laminated on the conductive support, and a conductive resin layer laminated as an outermost layer on the conductive elastic body layer. The conductive resin layer may contain a matrix material and resin particles. The conductive resin layer may have an arithmetic average roughness Ra of 2.0 to 7.0 ?m, a 10-point average roughness Rzjis of 15 to 40 ?m, and a skewness Rsk of 0.5 to 2.5.

Abstract: Provided is a development roller which is capable of improving a black solid density and a 2-dot density simultaneously to form a satisfactory image with excellent contrast and thin line reproducibility. A development roller includes a roller body that contains a tubular inner layer consisting of an elastic material and an outer layer consisting of an elastic material, a roller resistance value R1 (?, an applied voltage of 400 V) in a state when there is only the inner layer satisfies formula (1): 6.5?log R1?9.5??(1), and a volume resistivity R2 (?·cm, an applied voltage of 400 V) in a state when there is only the outer layer satisfies formula (2): log R2?9.0??(2).

Abstract: A height of convexities in a 0.7-mm-square area of a surface of the charging member is measured at five or more different positions in an axial direction and calculated. A height of a position where the charging member occupies 0.01 area % from a highest portion is defined as a reference height. An average proportion of areas occupied by the charging member at a position 1.7 ?m lower than the reference height is 2 area % or less relative to 100 area % of the 0.7-mm-square area.

Abstract: A cartridge includes a rotatable member, a rotatable rotational force receiving member, a preventing member including an accommodating portion, a rotatable coupling member including a free end portion which includes a rotational force receiving portion and including a connecting portion connected with the preventing portion to be partly accommodated in the accommodating portion so that a rotational axis of the coupling member permits tilting thereof relative to a rotational axis of the rotational force receiving member, a shaft portion. The preventing member includes a supporting portion for supporting ends of the shaft portion so as to prevent the shaft portion from moving in a rotational direction of the rotatable member to transmit the rotational force received from the shaft portion via the supporting portion to the rotational force receiving member.

Abstract: A conductive member includes a conductive substrate; and a conductive elastic layer disposed on the conductive substrate and exhibiting ionic conduction. The conductive elastic layer contains an elastic material, which contains epichlorohydrin rubber, and a layered inorganic compound, and the amount of free chlorine ions in the conductive elastic layer is 1 ?g/g or more and 80 ?g/g or less.

Abstract: A conductive member includes a conductive substrate; and a conductive elastic layer disposed on the conductive substrate and exhibiting ionic conduction. The conductive elastic layer contains an elastic material containing epichlorohydrin rubber, and the amount of free chlorine ions in the conductive elastic layer is 1 ?g/g or more and 80 ?g/g or less.

Abstract: A member for electrophotography has an electro-conductive base and at least one electro-conductive resin layer, in which the electro-conductive resin layer of the outermost layer contains urethane resin and the urethane resin has a structure of a silicone graft fluororesin and a structure represented by Formula (1)

Abstract: A cleaning blade includes a resin substrate having a substantially planar shape and a coating layer that covers at least one edge of the resin substrate and that has a connection layer and a surface layer, the connection layer being formed so as to face an interface with the resin substrate and containing diamond-like carbon and at least one selected from the group consisting of titanium nitride, titanium silicon, titanium tungsten, titanium carbide, and titanium carbonitride, the surface layer covering the connection layer and containing diamond-like carbon.

Abstract: Provided is a roller, in particular a conductive roller, capable of suppressing generation of cut debris from a cut surface of an end part of a foam layer in the roller axial direction over a long period of time, and an image forming device using the roller. A roller includes a shaft 1, a foam layer 2 and at least one film layer 3 sequentially provided on the outer periphery of the shaft. Both end parts in the roller axial direction of the foam layer and the film layer are cut, a filler layer 4 is provided on the cut surface of the cut foam layer and the cut film layer, at least the cut surface of the foam layer is covered with the filler layer, and the filler layer contains a water-based urethane resin.

Abstract: A developing roller is provided, which includes a roller body having a simplified structure without a coating film and yet having a higher wear resistance. The developing roller (1) includes a roller body (2) made of a crosslinked product of a rubber composition containing a rubber component including 20 to 50 parts by mass of ECO and/or GECO as an ion conductive rubber and 50 to 80 parts by mass of NBIR based on 100 parts by mass of the overall rubber component, and an oxide film (6) formed in an outer peripheral surface (5) of the roller body (2) by irradiation with ultraviolet radiation or the like.

Abstract: Provided is a developing roller including a shaft body, an elastic layer formed on an external circumference of the shaft body, and a surface layer formed on an external circumference of the elastic layer. The surface layer is formed of polyurethane containing a reaction product of a fluoroethylene vinyl ether copolymer and an isocyanurate form of isocyanate and having a film thickness of from 0.5 ?m through 2.0 ?m. The developing roller has grooves in a surface of the developing roller. The angle of the grooves from a circumferential direction is from 0 degrees through 30 degrees.

Abstract: It is an object of the present invention to provide a development roll rubber member that has a uniformly roughened surface on a rubber member surface, that is capable of ensuring a sufficient thickness without contaminating a peripheral portion while maintaining a flexibility in a coating layer and a convex portion without impairing softness of a rubber substrate layer, and that has the coating layer achieving non-tackiness and low friction, and a method of manufacturing the same, and the object is achieved by putting a reactive silicone oil, an isocyanate compound, and a diluent solvent capable of dissolving both the reactive silicone oil and the isocyanate compound into a reaction container, by causing a prepolymerization reaction in which the reactive silicone oil and the isocyanate compound are reacted into a polymerized state in the diluent solvent in the reaction container while dissolution in the solvent is maintained, by subsequently mixing a polyol and an isocyanate compound solution and using silic

Abstract: The present disclosure provides developing member superior in triboelectric charge imparting ability to a toner. The developing member includes a substrate and a surface layer, the surface layer containing alumina particles and a resin, the surface layer having protrusions on the surface thereof. Each of the protrusions containing the alumina particles, part or all of the alumina particles being exposed at the surfaces of the protrusions, and the resin being interposed among the alumina particles.

Abstract: An image forming apparatus includes: a heating unit; a pressure roller; a first frame supporting the heating unit; a second frame engaging the first frame; a first gear; a second gear; and a fixing member. The second frame supports a shaft portion of the pressure roller. The first gear is provided at one end of the shaft portion and rotatable with the pressure roller. The second gear engages the first gear and transmits a drive force to the first gear. The fixing member has a first portion engaging the shaft portion and a second portion engaging the second frame. At least a part of the first portion engages the shaft portion at a position on a downstream side of the shaft portion in a second direction in which the shaft portion receives a force upon transmission of the drive force.

Abstract: It is directed to providing a developing roller capable of forming a high-quality electrophotographic image. The developing roller includes a substrate, an electro-conductive elastic layer on the substrate, and a plurality of electrical insulating domains on the electro-conductive elastic layer. The developing roller has a length L of 200 mm or more in a longitudinal direction orthogonal to the circumferential direction thereof. The surface of the developing roller includes the surfaces of the domains and an exposed portion of the electro-conductive elastic layer, the exposed portion being uncovered with the domains. The developing roller has protrusions on the surface thereof, the protrusion being formed by the domains. The electro-conductive elastic layer has a plurality of protrusions at the exposed portion. The developing roller has an Asker C hardness of 50 degrees or more and 90 degrees or less.

Abstract: Provided is a roller capable of suppressing generation of cut waste from an end of a roller due to contact with another member inside a device when mounted on an image forming device, particularly a conductive roller, and an image forming device using the same. A roller includes a shaft 1 and a base layer 2 provided on the outer periphery of the shaft. A filler layer 4 covering the base layer is provided on end faces of both ends of the base layer in the roller axial direction, and the filler layer is composed of a material having a breaking strain measured according to a tensile test of JIS K 7127 of not less than 120% and a tensile stress at 100% elongation measured according to a tensile test of JIS K 7127 of from 5 to 30 N/mm2.

Abstract: A method of preparing the surface of a roller comprising adding a coating comprising isocyanate to a ground surface of the roller. A roller comprising a ground surface, the ground surface having unreacted hydroxyl (—OH) groups on the surface of the roller and a layer of isocyanate layered over the unreacted hydroxyl (—OH) groups on the surface of the roller, the isocyanate forming a urethane bond on the surface of the roller.

Abstract: A semiconductive roller (1) is provided, which is formed from a rubber composition containing a rubber component including: (1) an epichlorohydrin rubber; (2) at least one solid rubber selected from the group consisting of a solid BR and a solid SBR; and (3) at least one liquid rubber selected from the group consisting of a liquid BR and a liquid SBR.

Abstract: Provided is a lubricant composition for a refrigerator having the following characteristics: the composition being used for a refrigerator using a refrigerant having a specific structure such as an unsaturated fluorinated hydrocarbon compound serving as a refrigerant having a low global warming potential and usable particularly in current air-conditioning system for cars; the composition having excellent stability as well as excellent compatibility with the refrigerant; the composition including a base oil containing a polyoxyalkylene glycol derivative as a main component and 1 to 20% by mass of a monoepoxy compound based on the total amount of the composition; and the refrigerator using a refrigerant containing at least one kind of fluorine-containing organic compound selected from compounds represented by the molecular formula (A) CpOqFrRs or including a combination of the fluorine-containing organic compound and a saturated fluorinated hydrocarbon compound.

Abstract: A developing roller is provided, which is capable of controlling a solid black density and a dot density at higher levels than currently available levels. An image forming apparatus employing the developing roller is also provided. The developing roller (1) includes a tubular base layer (4) of an elastic material, and a surface layer (6) of an elastic material provided on an outer peripheral surface (5) of the base layer (4), wherein the thickness d1 (mm) of the surface layer, the roller resistance R? (log ? as measured with an application voltage of 10 V) of the base layer, and the roller resistance R (log ? as measured with an application voltage of 100 V) of a stack including the base layer and the surface layer satisfy the following expressions (1) to (3): 1.0?R?R???(1) 0.1?d1?2??(2) 7.5?R?8.5??(3) The image forming apparatus incorporates the developing roller.

Abstract: The present disclosure relates to a method for concentrating a substance, which may be an electrostatic printing ink. An apparatus for concentrating a substance is also described.

Abstract: A developing roller includes a roller main body disposed to face, without contact, an outer circumferential surface of an image carrier. The roller main body includes an aluminum oxide thin film and a resin coat layer, the aluminum oxide thin film being formed on an outer circumferential surface of a base body that is made of a metal including aluminum, the resin coat layer being formed on a surface of the aluminum oxide thin film that has been subjected to a predetermined heating process, the resin coat layer being made of a resin material and having electric conductivity.

Abstract: A transfer member includes a support, an elastic layer, and a resin layer having a sea-island structure on the elastic layer, wherein elongation at break of the resin layer is from 20% to 180%, and an average diameter of an island portion thereof is from 0.5 ?m to 3 ?m.

Abstract: A developing device includes a frame, a developing roller, a blade unit, and a first seal member. A blade unit extends in an axial direction of the developing roller and in contact with the peripheral surface thereof. The first seal member is configured to seal a boundary between the frame and the axial end portions of the developing roller. The frame has a fixing portion to which end portions of the blade is fixed. The fixing portion has a support surface having an outer edge and an inner edge in the axial direction. The outer edge is positioned outward of an inner edge of the first seal member in the axial direction, and the inner edge of the support surface is positioned inward of the inner edge of the first seal member in the axial direction.

Abstract: A developing roller that is capable of carrying toner on a surface thereof, and that supplies the toner carried on the surface to a surface of a photosensitive drum when a voltage is applied thereto, includes: a rubber layer; and a surface layer that covers the rubber layer, contains alumina, and has a higher volume resistivity than the rubber layer.