Charged member, manufacturing apparatus and method thereof, charging apparatus, process cartridge, and image forming apparatus

Abstract

To provide a charging member that excels at suppressing density unevenness in the resulting image. [Solution] A charger comprising a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and the maximum value of the variation in layer thickness from the approximate crown curve of the elastic layer is less than 10 μm.

Description

[Technical Field]

[0001] The present invention relates to a charging member, a manufacturing apparatus and manufacturing method therefor, a charging device, a process cartridge, and an image forming apparatus. [Background Art]

[0002] Patent Document 1 discloses a method for manufacturing a rubber roll, comprising: a first step of sequentially feeding core bars at intervals into a central portion of an unvulcanized rubber material extruded into a cylindrical shape, and alternately discharging rubber roll portions each having an outer peripheral surface of the core bar covered with the rubber material, and an intermediate portion between a leading core bar and a trailing core bar where no core bar exists in the central portion of the rubber material; a second step of performing a vulcanization treatment on the rubber material; and a third step of cutting off the rubber material at portions on both end sides in the longitudinal direction of the core bar to expose both end portions of the core bar to the outside, wherein when an exposure length for exposing both end sides of the core bar in the third step is defined as L, a length of a portion of the core bar covered with the rubber material in the first step is 7L / 10 or less and 2 mm or more.

[0003] Patent Document 2 discloses an apparatus for manufacturing a rubber roll, comprising: an extrusion section having an extrusion die that extrudes an unvulcanized rubber material into a cylindrical shape, and a core bar supply section that supplies a core bar to the central portion of the rubber material extruded into the cylindrical shape in order to coat an outer peripheral surface of the core bar with the rubber material, wherein the extrusion die has a land portion whose length satisfies the following formula (1) with respect to the relationship between a pressure (P0) when only the rubber material is extruded from the extrusion die and a pressure (P1) when the rubber material is extruded from the extrusion die in a state where the core bar is supplied. Formula (1): -0.10≦(P0-P1) / P0≦0.10 [Prior Art Document] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-147434 [Patent Document 2] Japanese Patent Publication No. 2015-30168 [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide a charging member that has a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is less than 15% by mass or more than 40% by mass of the total mass of the rubber material, or the maximum value of the variation in layer thickness from the approximate crown curve of the elastic layer is 10 μm or more, compared to a case in which the resulting image density unevenness is suppressed. [Means for solving the problem]

[0006] The means for solving the above problems include the following embodiments. <1> A charger comprising a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and the maximum value of the variation in layer thickness from the approximate crown curve of the elastic layer is less than 10 μm. <2> The content of the filler is 15% by mass or more and 25% by mass or less, relative to the total mass of the rubber material. <1> The electrostatic component described above. <3> The rubber material includes an epichlorohydrin-based rubber. <1> or <2> The electrostatic component described above. <4> The elastic layer further comprises a conductive agent <1> ~ <3> A charged material as described in any one of the following. <5> The Mooney viscosity of the elastic layer is 30 or more and 60 or less. <1> ~ <4> A charged material as described in any one of the following. <6> <1> ~ <5> A charging device having a charging member as described in any one of the following. <7> Photoreceptor and <1> ~ <5> A process cartridge that is attached to and detached from an image forming apparatus, comprising a charging device having a charging member as described in any one of the above, for charging the photoreceptor, and the process cartridge. <8> Photoreceptor and <1> ~ <5> An image forming apparatus comprising: a charging device having a charging member as described in any one of the above, for charging the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged photoreceptor; a developing device for developing the electrostatic latent image formed on the surface of the photoreceptor with a developer containing toner to form a toner image; and a transfer device for transferring the toner image to the surface of a recording medium. <9> The extrusion unit comprises an extrusion die for extruding unvulcanized rubber material into a cylindrical shape, and a core supply unit for supplying a core to the center of the cylindrically extruded rubber material in order to cover the outer surface of the core with the rubber material, wherein the inner diameter of the extrusion die does not change in the direction of the rubber material extrusion, and the cylindrical rubber material with the core fed to the center passes through in the extrusion direction, and the relationship 108% ≤ (T / S) ≤ 112% is satisfied when the thickness of the elastic layer of the resulting molded product is S and the flow path width of the land is T. <1> ~ <5> A manufacturing apparatus for the charged material described in any one of the following. <10> When the length of the land portion in the extrusion direction is L, the relationship 200% ≤ (L / S) ≤ 400% is satisfied. <9> A manufacturing apparatus for the electrostatically charged material described above. <11> The process comprises: a first step of supplying a core to the center of the unvulcanized rubber material extruded cylindrically from the extrusion die of an extrusion section having an extrusion die, and covering the outer surface of the core with the rubber material; and a second step of performing a vulcanization treatment on the rubber material that has covered the outer surface of the core, wherein the inner surface of the extrusion die has an inner diameter that does not change in the direction of the rubber material extrusion along the direction of the rubber material extrusion, and has a land portion through which the cylindrical rubber material with the core fed into the center passes in the extrusion direction, and satisfies the relationship 108% ≤ (T / S) ≤ 112% when the thickness of the elastic layer of the resulting molded product is S and the flow path width of the land portion is T. <1> ~ <5> A method for manufacturing a charged member as described in any one of the following. <12> When the length of the land portion in the extrusion direction is L, the relationship 200% ≤ (L / S) ≤ 400% is satisfied. <11> A method for manufacturing a charged member as described above. [Effects of the Invention]

[0007] <1> , <3> or <4> According to this, a charging member is provided that has a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is less than 15% by mass or more than 40% by mass of the total mass of the rubber material, or the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer is 10 μm or more, compared to a case in which the resulting image density unevenness is suppressed. <2> According to this, a charging member is provided that exhibits superior suppression of density unevenness in the resulting image compared to cases where the content of the filler is less than 15% by mass or more than 25% by mass relative to the total mass of the rubber material. <5> According to this, a charging member is provided that exhibits superior suppression of density unevenness in the resulting image compared to cases where the Mooney viscosity of the elastic layer is less than 30 or greater than 60. <6> , <7> or <8> According to this, a charging device, process cartridge, or image forming apparatus is provided that has a charging member having a support member and an elastic layer provided on the support member, the surface of the elastic layer being a non-abrasive surface, the elastic layer containing a rubber material and a filler, the filler content being less than 15% by mass or more than 30% by mass of the total mass of the rubber material, or the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer being 10 μm or more, which provides superior suppression of density unevenness in the resulting image. <9> According to this, a manufacturing apparatus for a charged member is provided that, when the thickness of the elastic layer of the obtained molded product is S and the width of the flow channel in the land portion is T, satisfies the relationship 108% ≤ (T / S) ≤ 112%, compared to the case where this relationship is not satisfied. <10> According to this, a manufacturing apparatus for a charged member is provided that is superior in suppressing density unevenness in the resulting image compared to the case where the relationship 200% ≤ (L / S) ≤ 400% is not satisfied when the length of the land portion in the extrusion direction is L. <11> According to this, a method for manufacturing a charged member is provided that, when the thickness of the elastic layer of the resulting molded product is S and the width of the flow channel in the land portion is T, satisfies the relationship 108% ≤ (T / S) ≤ 112%, and is superior in suppressing density unevenness in the resulting image. <12> According to this, a method for manufacturing a charged member is provided that is superior in suppressing density unevenness in the resulting image compared to the case where the relationship 200% ≤ (L / S) ≤ 400% is not satisfied when the length of the land portion in the extrusion direction is L. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the configuration of a manufacturing apparatus for a charged member according to this embodiment. [Figure 2] This is an enlarged cross-sectional view showing the confluence area in the manufacturing apparatus for the charged member according to this embodiment. [Figure 3] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 4] This is a schematic diagram showing another example of the image forming apparatus according to this embodiment. [Modes for carrying out the invention]

[0009] The following describes an example of the present invention. These descriptions and examples are illustrative and do not limit the scope of the embodiments.

[0010] In this specification, "A and / or B" is synonymous with "at least one of A and B." In other words, "A and / or B" may be A alone, B alone, or a combination of A and B.

[0011] In the present specification, a numerical range indicated using "~" represents a range including the numerical values described before and after "~" as the minimum value and maximum value thereof, respectively. In the numerical ranges described stepwise in the present specification, an upper limit or a lower limit described in one numerical range may be replaced with an upper limit or a lower limit of a numerical range described in another stepwise description. Further, in the numerical ranges described in the present specification, the upper limit or the lower limit of the numerical range may be replaced with a value shown in the examples.

[0012] In the present specification, the term "step" includes not only an independent step but also a case that cannot be clearly distinguished from other steps as long as the object of the step is achieved.

[0013] When embodiments are described in the present specification with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of each member in each drawing is conceptual, and the relative relationship of the sizes between members is not limited thereto.

[0014] In the present specification, each component may contain a plurality of types of corresponding substances. When referring to the amount of each component in the composition in the present specification, if a plurality of types of substances corresponding to each component are present in the composition, it means the total amount of the plurality of types of substances present in the composition, unless otherwise specified. In the present specification, a plurality of types of particles corresponding to each component may be contained. When a plurality of types of particles corresponding to each component are present in the composition, the particle diameter of each component means a value for a mixture of the plurality of types of particles present in the composition, unless otherwise specified.

[0015] In the present specification, the "axial direction" of the charging member means the direction in which the rotation shaft of the charging member extends, and the "circumferential direction" of the charging member means the rotation direction of the charging member.

[0016] (Charging Member) The charging member according to this embodiment comprises a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and the maximum variation in layer thickness from the approximate crown curve of the elastic layer is less than 10 μm.

[0017] Conventional electrostatic components have been designed to extend their lifespan by reducing the resistance and Young's modulus of the electrostatic roll, aiming to suppress wear on the photoreceptor and reduce discharge stress. One method to achieve this is to reduce the amount of fillers, such as calcium carbonate, contained in the elastic layer. This increases the proportion of conductive components and decreases the solid content, thereby achieving a lower Young's modulus. However, it is known that reducing the fillers increases the elastic components of the unvulcanized rubber, which significantly reduces processability, such as in extrusion molding. In the charging member according to this embodiment, the content of the filler is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and the maximum value of the layer thickness deviation from the approximate crown curve of the elastic layer is 10 μm or less. As a result, a good crown shape of the elastic layer is stably obtained, and the shape of the charging member is stable, resulting in excellent suppression of density unevenness in the obtained image.

[0018] The shape of the charging member according to this embodiment is not limited to a roll shape, but can also be a belt shape, a tube shape, a blade shape, or the like.

[0019] <Filler content> In the charging member according to this embodiment, the elastic layer comprises a rubber material and a filler, wherein the filler content is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and from the viewpoint of suppressing density unevenness in the resulting image, it is preferably 15% by mass or more and 30% by mass or less, and more preferably 15% by mass or more and 25% by mass or less.

[0020] <Maximum value of thickness variation from the approximate crown curve of the elastic layer> In this embodiment, the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer of the charging member is less than 10 μm, and from the viewpoint of suppressing density unevenness in the resulting image, it is preferably 8.0 μm or less, more preferably 6.5 μm or less, and particularly preferably 5.0 μm or less. The lower limit is 0 μm. The smaller the maximum value of the layer thickness variation, the better the suppression of density unevenness in the resulting image.

[0021] The method for measuring the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer in this embodiment is as follows. To measure the outer diameter of the elastic layer, a light-shielding laser outer diameter measuring device (ROLL2000, manufactured by Asaka Riken Co., Ltd.) is used. Specifically, both ends of the elastic layer to be measured are supported, and the profile of the outer circumference of the elastic layer from one end to the other in the axial direction is measured. This measurement is performed at 15° intervals in the circumferential direction of the elastic layer. Then, the error relative to the approximate crown curve (radius, quadratic curve) is calculated, and the largest value among the errors is taken as the maximum error (maximum value of the layer thickness variation).

[0022] The following describes each layer of the charged component in detail.

[0023] <Support member> The support member is a conductive member that functions as an electrode and support for the charged member. The support member may be a hollow member or a non-hollow member, for example, a rod-shaped, cylindrical, or endless belt-shaped member.

[0024] Examples of support members include metal members such as iron (free-cutting steel, etc.), copper, copper alloys, brass, stainless steel, aluminum, and nickel; iron members plated with chromium, nickel, etc.; resin or ceramic members with plated outer surfaces; and resin or ceramic members containing conductive agents.

[0025] <Elastic layer> The elastic layer is conductive, and its volume resistivity at 20°C is 1 × 10⁻⁶. 3 Ω cm or more 1×10 14It is preferable that the value is Ω·cm or less.

[0026] The volume resistivity of the elastic layer is the value measured by the following method. After removing the surface layer of the charged material by polishing, the elastic layer is cut from the axial center of the charged material to a length of 25 mm in the axial direction and 8 mm in the circumferential direction, and this is used as the sample. The thickness of the sample (i.e., the elastic layer) is measured. Using a measuring jig (R12702A / B Resistivity Chamber: Advantest Corporation) and a high-resistance meter (R8340A Digital High-Resistance / Micro-Ammeter: Advantest Corporation) in accordance with JIS K 6911:1995, a voltage adjusted to produce an electric field (applied voltage / composition sheet thickness) of 1000 V / cm is applied to the sample for 30 seconds. The current value is read and calculated using the following formula. Volume resistivity (Ω cm) = (sample area (cm 2 ((Current value (A) × Applied voltage (V)) / (Sample thickness (cm))

[0027] The elastic layer may be a foamed elastic layer or a non-foamed elastic layer. The elastic layer may be directly placed on the outer surface of the support member, or it may be placed on the outer surface of the support member via an adhesive layer.

[0028] An example of an elastic layer embodiment includes a rubber material, a filler, a conductive agent, and other additives.

[0029] Examples of rubber materials include polyurethane, nitrile rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, and epichlorohydrate. Examples of elastic materials include dilin rubber, epichlorohydrin-ethylene oxide rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butadiene rubber, chloroprene rubber, chlorinated polyisoprene, hydrogenated polybutadiene, butyl rubber, silicone rubber, fluororubber, natural rubber, and elastic materials obtained by mixing two or more of these. Among these elastic materials, polyurethane, silicone rubber, ethylene-propylene-diene rubber, epichlorohydrin-ethylene oxide rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether rubber, acrylonitrile-butadiene rubber, and elastic materials obtained by mixing two or more of these are preferred. In particular, it is preferable that the material contains epichlorohydrin-based rubber.

[0030] Examples of fillers include calcium carbonate, silica, and clay minerals. A single filler may be used, or two or more may be used in combination. Among these, calcium carbonate is preferred as a filler.

[0031] The elastic layer preferably further contains a conductive material. Examples of conductive agents include electronic conductive agents and ionic conductive agents. Examples of electronic conductive agents include powders such as carbon black such as furnace black, thermal black, channel black, Ketjen black, acetylene black, and color black; pyrolytic carbon; graphite; metals or alloys such as aluminum, copper, nickel, and stainless steel; metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, and tin oxide-indium oxide solid solution; and materials whose insulating surfaces have been treated to become conductive. Examples of ionic conductive agents include perchlorates or chlorates such as tetraethylammonium, lauryltrimethylammonium, and benzyltrialkylammonium; and perchlorates or chlorates of alkali metals or alkaline earth metals such as lithium and magnesium. Conductive agents may be used individually or in combination of two or more types.

[0032] The total amount of conductive agent contained in the elastic layer is preferably set based on the volume resistivity of the elastic layer. When an electronically conductive agent is used as the conductive material, the total amount of the electronically conductive agent may be, for example, 1 to 20 parts by mass, or 3 to 20 parts by mass, per 100 parts by mass of the elastic material. When an ionic conductive agent is used as the conductive material, the total amount of the ionic conductive agent may be, for example, 0.1 parts by mass or more and 10 parts by mass or 0.5 parts by mass or more and 5 parts by mass per 100 parts by mass of the elastic material.

[0033] The average primary particle size of the conductive agent is preferably between 1 nm and 500 nm, and more preferably between 5 nm and 200 nm. The average primary particle size of the conductive agent is determined by observing the cross-section of the elastic layer with an electron microscope, measuring the major axis of 100 conductive agent particles, and taking the arithmetic mean of the results.

[0034] Carbon black is preferred as the conductive agent. The average primary particle size of the carbon black is preferably 1 nm to 500 nm, and more preferably 5 nm to 200 nm. The carbon black content is preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of elastic material.

[0035] Other additives include vulcanizing agents, vulcanization accelerators, vulcanization accelerators, softeners, plasticizers, hardeners, antioxidants, surfactants, and coupling agents.

[0036] The Mooney viscosity of the elastic layer is preferably 20 to 70, more preferably 30 to 60, and particularly preferably 40 to 55, from the viewpoint of suppressing density unevenness in the resulting image. In this embodiment, the Mooney viscosity is the value measured in accordance with JIS K6300-1 (2001).

[0037] The thickness S of the elastic layer is preferably 0.5 mm or more and 20 mm or less, more preferably 1.0 mm or more and 10 mm or less, and particularly preferably 1.5 mm or more and 5.0 mm or less. The thickness of the elastic layer is measured by imaging the cross-section with an electron microscope. Measurements are taken at four points in the circumferential direction at 90° intervals in the axial center of the charged member, and the arithmetic mean value is taken as the thickness of the elastic layer.

[0038] Methods for forming an elastic layer on a support member include, for example, extruding an elastic layer-forming composition, which is a mixture of an elastic material, a conductive agent, and other additives, and a cylindrical support member together from an extrusion molding machine to form a layer of the elastic layer-forming composition on the outer surface of the support member, and then heating the layer of the elastic layer-forming composition to cause a crosslinking reaction (including vulcanization) to form an elastic layer; and extruding an elastic layer-forming composition, which is a mixture of an elastic material, a conductive agent, and other additives, from an extrusion molding machine onto the outer surface of an endless belt-shaped support member to form a layer of the elastic layer-forming composition on the outer surface of the support member, and then heating the layer of the elastic layer-forming composition to cause a crosslinking reaction (including vulcanization) to form an elastic layer. The support member may have an adhesive layer on its outer surface.

[0039] [Adhesive layer] An adhesive layer may be provided between the support member and the elastic layer to bond them together. Specific examples of adhesive layers interposed between the support member and the elastic layer include layers containing resins such as polyolefin, acrylic resin, epoxy resin, polyurethane, nitrile rubber, chlorine rubber, vinyl chloride resin, vinyl acetate resin, polyester, phenolic resin, and silicone resin. The adhesive layer may also contain a conductive agent (for example, the aforementioned electronic conductive agent or ionic conductive agent).

[0040] From the viewpoint of adhesion between the elastic layer and the support member, the thickness of the adhesive layer is preferably 1 μm to 50 μm, more preferably 2 μm to 40 μm, and even more preferably 5 μm to 20 μm. The thickness of the adhesive layer is measured by imaging the cross-section with an electron microscope. Measurements are taken at four points in the circumferential direction at 90° intervals in the axial center of the charged member, and the arithmetic mean value is taken as the thickness of the adhesive layer.

[0041] [Surface layer] The charging member according to this embodiment may have a surface layer on the elastic layer. The surface layer preferably contains a resin, conductive particles, and non-conductive inorganic particles.

[0042] Resins include copolymer nylon, polyamide, polyimide, polyamide-imide, polyvinyl butyral, polyester, polyethylene terephthalate, polyarylate, polycarbonate, polyethylene, polyurethane, phenolic resin, silicone resin, acrylic resin, fluorine-modified acrylic resin, silicone-modified acrylic resin, melamine resin, epoxy resin, fluororesin, polyvinylidene fluoride resin, tetrafluoroethylene resin, ethylene-tetrafluoroethylene Examples include tetrafluoroethylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, fluororubber, polyvinyl resins, polyvinyl alcohol, polyvinyl acetal, polyvinylidene chloride, polyvinyl chloride, ethylene vinyl acetate copolymers, cellulose, polythiophene resins, resins obtained by mixing two or more of these, and resins obtained by curing or crosslinking at least one of these with a curing agent or catalyst. The resins may be used individually or in combination of two or more.

[0043] From the viewpoint of suppressing contamination of the surface layer, the resin contained in the surface layer is preferably polyamide, polyvinylidene fluoride resin, or tetrafluoroethylene resin, with polyamide being more preferred. As for polyamide, from the viewpoint of suppressing contamination of the surface layer, alcohol-soluble polyamide is preferred, alkoxymethylated polyamide (e.g., alkoxymethylated nylon) is more preferred, and methoxymethylated polyamide (e.g., methoxymethylated nylon) is even more preferred.

[0044] The surface layer preferably contains polyvinyl butyral from the viewpoint of binding non-conductive inorganic particles. One example of a surface layer embodiment contains polyamide and polyvinyl butyral as the binder resin. In this case, the mass ratio of the two is preferably polyamide:polyvinyl butyral = 95:5 to 65:35, more preferably 90:10 to 70:30, and even more preferably 85:15 to 75:25.

[0045] Examples of conductive particles include carbon black; metal oxides such as tin oxide, titanium oxide, and zinc oxide; etc. Carbon black is preferred as the conductive particle included in the surface layer. Conductive particles may be used individually or in combination of two or more types.

[0046] From the viewpoint of excellent dispersibility in the resin, the conductive particles contained in the surface layer preferably have an average primary particle size of 10 nm to 50 nm. The average primary particle size of conductive particles is determined by observing a cross-section of the surface layer with an electron microscope, measuring the major axis of 100 conductive particles, and taking the arithmetic mean of these measurements.

[0047] The content of conductive particles in the surface layer is preferably 5 to 50 parts by mass, more preferably 8 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of resin.

[0048] The surface layer preferably contains non-conductive inorganic particles to enhance the heat dissipation of the charged member. The non-conductive inorganic particles preferably have a thermal conductivity of 20 W / (m·K) or higher, more preferably 30 W / (m·K) or higher, and even more preferably 40 W / (m·K) or higher. The thermal conductivity of non-conductive inorganic particles may be, for example, 150 W / (m·K) or less, 120 W / (m·K) or less, or 100 W / (m·K) or less.

[0049] The thermal conductivity of non-conductive inorganic particles is measured according to JIS R1611:2010 "Method for measuring thermal diffusivity, specific heat capacity, and thermal conductivity of fine ceramics by flash method". The particles to be measured are filled into the sample holder of the measuring device, and the bulk density is adjusted by applying a load according to the specifications of the measuring device. The measurement is performed in an environment with a temperature of 23°C and a relative humidity of 50%. The non-conductive inorganic particles used for measurement are non-conductive inorganic particles that form the surface layer, or non-conductive inorganic particles extracted from the surface layer. There are no restrictions on the method for extracting non-conductive inorganic particles from the surface layer. For example, the method involves immersing the surface layer peeled off from the charged member in an organic solvent that dissolves the binder resin to extract the non-conductive inorganic particles; or heating the surface layer peeled off from the charged member to a high temperature to remove the binder resin and extract the non-conductive inorganic particles. Methods for extracting particles; and so on.

[0050] As non-conductive inorganic particles, fine ceramic particles are preferred from the viewpoint of excellent thermal conductivity. Examples of fine ceramic particles include nitride particles, oxide particles, carbide particles, and boride particles.

[0051] Examples of nitride particles include aluminum nitride, boron nitride, and silicon nitride. Examples of oxide particles include magnesium oxide and aluminum oxide particles. Examples of carbide particles include silicon carbide particles. Examples of boride particles include titanium boride, niobium boride, and molybdenum boride. These particles may be used individually or in combination of two or more types.

[0052] As non-conductive inorganic particles, from the viewpoint of excellent thermal conductivity, at least one selected from the group consisting of nitride particles and oxide particles is preferred, and at least one selected from the group consisting of aluminum nitride particles, boron nitride particles and magnesium oxide particles is more preferred.

[0053] The non-conductive inorganic particles contained in the surface layer preferably have an average primary particle size of 5 μm to 20 μm, more preferably 5 μm to 15 μm, and even more preferably 5 μm to 10 μm. If the average primary particle size of the non-conductive inorganic particles is 5 μm or larger, fine irregularities (i.e., discharge initiation points that discharge to the photosensitive layer) can be formed on the surface of the surface layer. If the average primary particle size of non-conductive inorganic particles is 20 μm or less, cracks are less likely to occur in the surface layer. The average primary particle size of non-conductive inorganic particles is determined by observing a cross-section of the surface layer with an electron microscope, measuring the major axis of 100 non-conductive inorganic particles, and taking the arithmetic mean of these measurements.

[0054] The amount of non-conductive inorganic particles contained in the surface layer is preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, and more preferably 15 to 25 parts by mass, per 100 parts by mass of resin, from the viewpoint of the surface layer having excellent heat dissipation properties and suppressing crack formation.

[0055] The surface layer may contain various additives. Examples of additives include fillers, softeners, plasticizers, hardeners, antioxidants, coupling agents, surfactants, defoamers, and leveling agents.

[0056] The thickness of the surface layer is preferably 1 μm to 25 μm, preferably 3 μm to 20 μm, and more preferably 5 μm to 15 μm. The thickness of the surface layer is measured by imaging the cross-section with an electron microscope. Measurements are taken at four points in the circumferential direction at 90° intervals in the axial center of the charged member, and the arithmetic mean value is taken as the thickness of the surface layer.

[0057] One method for forming a surface layer on an elastic layer is to apply a surface layer forming composition, which is a mixture of resin, conductive particles, non-conductive inorganic particles, and other additives, to the outer surface of the elastic layer to form a layer of the surface layer forming composition, and then to dry the layer of the surface layer forming composition. Examples of methods for applying the surface layer forming composition to the outer surface of the elastic layer include immersion coating, roll coating, blade coating, wire bar coating, spray coating, bead coating, air knife coating, curtain coating, and the like.

[0058] (Manufacturing apparatus for charged materials, and method for manufacturing charged materials) The apparatus for manufacturing a charged member according to this embodiment comprises an extrusion section having an extrusion die for extruding unvulcanized rubber material into a cylindrical shape, and a core supply section for supplying a core to the center of the cylindrically extruded rubber material in order to cover the outer surface of the core with the rubber material, wherein the inner diameter of the extrusion die does not change in the direction of the extrusion of the rubber material along the extrusion direction of the rubber material, and has a land section through which the cylindrical rubber material with the core fed to the center passes in the extrusion direction, and it is preferable that the relationship 108%≦(T / S)≦112% is satisfied when the thickness of the elastic layer of the resulting molded product is S and the flow path width of the land section is T, and it is more preferable that the relationship 200%≦(L / S)≦400% is satisfied when the length of the land section in the extrusion direction is L.

[0059] The method for manufacturing a charged member according to this embodiment comprises a first step of supplying a core to the center of the unvulcanized rubber material extruded cylindrically from the extrusion die of an extrusion section having an extrusion die, and covering the outer surface of the core with the rubber material, and a second step of performing a vulcanization treatment on the rubber material that has covered the outer surface of the core, wherein the inner surface of the extrusion die has an inner diameter that does not change in the direction of the extrusion of the rubber material along the extrusion direction of the rubber material, and has a land portion through which the cylindrical rubber material with the core fed to the center passes in the extrusion direction, and it is preferable that the relationship 108% ≤ (T / S) ≤ 112% is satisfied when the thickness of the elastic layer of the resulting molded product is S and the flow path width of the land portion is T, and it is more preferable that the relationship 200% ≤ (L / S) ≤ 400% is satisfied when the length of the land portion in the extrusion direction is L.

[0060] Furthermore, it is more preferable that the relationship 109% ≤ (T / S) ≤ 111% is satisfied when S is the thickness of the elastic layer of the resulting molded product and T is the width of the flow channel in the land portion. Furthermore, it is even more preferable that the relationship 250% ≤ (L / S) ≤ 350% is satisfied when the length of the land portion in the extrusion direction is L.

[0061] An example of a manufacturing apparatus for a charged member according to this embodiment, and an example of a method for manufacturing a charged member according to this embodiment, will be described with reference to Figures 1 and 2. In the figures, arrow H indicates the vertical direction of the apparatus, and arrow W indicates the horizontal direction of the apparatus.

[0062] The electrostatic member manufacturing apparatus 10 according to this embodiment, as shown in Figure 1, comprises an extruder 12 composed of a so-called crosshead die, a press 14 located below the extruder 12, and a drawer 16 located below the press 14. The electrostatic member manufacturing apparatus 10 also comprises a cutting machine (not shown) and a control unit 78 that controls each part.

[0063] <Extruder> The extruder 12 includes a rubber material supply unit 18 that supplies unvulcanized rubber material, an extrusion unit 20 that extrudes the rubber material supplied from the rubber material supply unit 18 into a cylindrical shape, and a core metal supply unit 24 that supplies a core metal 22 to the center of the rubber material extruded cylindrically from the extrusion unit 20.

[0064] <Rubber Material Supply Department> The rubber material supply unit 18 includes a screw 28 located inside a cylindrical main body 26, a heater (not shown) for heating the rubber material inside the main body 26, and a drive motor 30 located on the right side of the main body 26 in the figure, which rotates the screw 28. Furthermore, an input port 32 for feeding rubber material is located on the drive motor 30 side of the main body 26.

[0065] In this configuration, the rubber material introduced from the input port 32 is kneaded by the screw 28 inside the main body 26 and then sent out toward the extrusion section 20.

[0066] <Extrusion section> The extrusion unit 20 comprises a cylindrical case 34 connected to the rubber material supply unit 18, a cylindrical mandrel 36 positioned inside the case 34, and a discharge head 38 positioned below the mandrel 36. The mandrel 36 is held in the case 34 by a holding member 40, and the discharge head 38 is held in the case 34 by a holding member 42. An annular channel 44 is formed between the outer circumferential surface of the mandrel 36 (partially the outer circumferential surface of the holding member 40) and the inner circumferential surface of the holding member 42 (partially the inner circumferential surface of the discharge head 38) through which the rubber material flows in an annular manner.

[0067] Furthermore, a through hole 46 is formed in the center of the mandrel 36 through which the core metal 22 is inserted and passed. On the other hand, the tip side (lower end side) of the mandrel 36 has a tapered shape towards the tip. The area below the tip of the mandrel 36 is a confluence region 48 where the core metal 22 supplied from the through hole 46 and the rubber material supplied from the annular channel 44 merge. In other words, the rubber material is extruded in a cylindrical shape toward this confluence region 48, and the core metal 22 is fed into the center of the cylindrically extruded rubber material.

[0068] The length of the portion of the core metal 22 covered with rubber material in the confluence area 48 will be described in detail later.

[0069] <Core metal supply section> The core metal supply unit 24 is equipped with a roller pair 50 positioned above the mandrel 36. Multiple pairs (for example, three pairs) of roller pairs 50 are provided, and the roller on one side (left side in the figure) of each roller pair 50 is connected to a drive roller 54 via a belt 52. When the drive roller 54 is driven, the core metals 22 gripped by each roller pair 50 are fed toward the through hole 46 of the mandrel 36. The core metals 22 are of a predetermined length, and the rear core metals 22 fed by the roller pair 50 push the front core metals 22 already inside the through hole 46 of the mandrel 36, causing multiple core metals 22 to pass through the through hole 46 sequentially.

[0070] In this configuration, the drive of the drive roller 54 is temporarily stopped when the tip of the leading core metal 22 reaches the tip of the mandrel 36 (not shown). Then, the core metals 22 are sequentially fed into the center of the rubber material at intervals. As a result, the rubber roll section 56, in which the outer surface of the core metal 22 is covered with rubber material, and the intermediate section 58, in which there is no core metal 22 inside the rubber material between the core metals 22, are discharged alternately from the discharge head 38. Note that a primer is pre-applied to the outer surface of the core metal 22 to improve adhesion with the rubber material.

[0071] <Pressing machine> The pressing machine 14 is equipped with a pair of semi-cylindrical pressing members 60. The pair of pressing members 60 are positioned opposite each other, sandwiching the rubber roll section 56 discharged from the extruder 12. Each pressing member 60 has a pressing portion 62 that protrudes toward the center. Each pressing member 60 is movable in the left-right direction in the figure by a drive mechanism (not shown).

[0072] <Drawer machine> The puller 16 has a pair of semi-cylindrical gripping members 64. The pair of gripping members 64 are positioned opposite each other so as to sandwich the rubber roll section 56 discharged from the extruder 12. Each gripping member 64 has a gripping portion 66 formed in a shape corresponding to the outer surface shape of the rubber roll section 56. Each gripping member 64 is movable in the left-right and up-down directions by a drive mechanism (not shown).

[0073] <Cutting machine> The cutting machine (not shown) comprises a pair of gripping members that grip both ends of a rubber roll body in which the core metal 22 is sealed, and a pair of cutters.

[0074] The gripping member is designed to rotate the gripped rubber roll in the circumferential direction, while the cutter is designed to move toward and away from the gripped rubber roll.

[0075] In this configuration, the cutting machine cuts off the rubber material covering the end face of the core metal 22, thereby forming a rubber roll in which the ends of the core metal 22 are exposed.

[0076] Furthermore, the flow path width of the land section is dimension T shown in Figure 2, which is the thickness of the portion where the rubber material covers the core metal 22, and the length of the land section in the extrusion direction is dimension L shown in Figure 2, which is the length in the extrusion direction of the portion where the rubber material covers the core metal 22 in the confluence region 48 (the portion with the same diameter inner circumferential surface 38A).

[0077] (Charging equipment, image forming equipment, process cartridges) The charging device according to this embodiment has a charging member according to this embodiment. The charging device according to this embodiment may be a charging device in which the charging member is in contact with the surface of the photoreceptor, or it may be a charging device in which the charging member is not in contact with the surface of the photoreceptor.

[0078] The image forming apparatus according to this embodiment comprises a photoreceptor, a charging device for charging the surface of the photoreceptor, an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoreceptor, a developing device for developing the electrostatic latent image formed on the surface of the photoreceptor with a developer containing toner to form a toner image, and a transfer device for transferring the toner image to the surface of a recording medium. The charging device is a charging device having a charging member according to this embodiment. The charging device may be a charging device in which the charging member contacts the surface of the photoreceptor, or a charging device in which the charging member does not contact the surface of the photoreceptor.

[0079] In the image forming apparatus according to this embodiment, for example, the part comprising the photoreceptor and the charging device may be a cartridge structure that can be attached to and detached from the image forming apparatus (i.e., a process cartridge according to this embodiment). In addition to the photoreceptor and the charging device, the process cartridge may include at least one selected from the group consisting of, for example, an electrostatic latent image forming device, a developing device, and a transfer device. The charging device may be a charging device in which the charging member contacts the surface of the photoreceptor, or a charging device in which the charging member does not contact the surface of the photoreceptor.

[0080] The image forming apparatus according to this embodiment includes known image forming apparatuses such as: an apparatus equipped with a fixing device for fixing a toner image transferred to the surface of a recording medium; a direct transfer apparatus for directly transferring a toner image formed on the surface of a photoreceptor to a recording medium; an intermediate transfer apparatus for first transferring a toner image formed on the surface of a photoreceptor to the surface of an intermediate transfer body, and secondarily transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with a cleaning device for cleaning the surface of the photoreceptor after the transfer of the toner image and before charging; an apparatus equipped with a static elimination device for irradiating the surface of the photoreceptor with static elimination light to eliminate static charge after the transfer of the toner image and before charging; and an apparatus equipped with a photoreceptor heating member for raising the temperature of the photoreceptor and reducing the relative temperature.

[0081] In the case of an intermediate transfer method apparatus, the transfer apparatus may be configured to include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer apparatus that first transfers the toner image formed on the surface of the photoreceptor to the surface of the intermediate transfer body; and a secondary transfer apparatus that secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0082] The image forming apparatus according to this embodiment may be either a dry developing type image forming apparatus or a wet developing type image forming apparatus (a developing method using a liquid developer).

[0083] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and the descriptions of other parts will be omitted.

[0084] Figure 3 is a schematic diagram showing an example of an image forming apparatus according to this embodiment. As shown in Figure 3, the image forming apparatus 100 according to this embodiment comprises a process cartridge 300, an exposure apparatus 9 (an example of an electrostatic latent image forming apparatus), a transfer apparatus 40 (a primary transfer apparatus), and an intermediate transfer body 50. In the image forming apparatus 100, the exposure apparatus 9 is a process cartridge The transfer device 40 is positioned so that the photoreceptor 7 can be exposed through the opening of the 300, and the transfer device 40 is positioned opposite the photoreceptor 7 via the intermediate transfer body 50, with a portion of the intermediate transfer body 50 in contact with the photoreceptor 7. Although not shown, there is also a secondary transfer device that transfers the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) are examples of a transfer device.

[0085] In Figure 3, the process cartridge 300 integrally supports a photoreceptor 7, a charging device 8, a developing device 11, and a cleaning device 13 within a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, which is positioned to contact the surface of the photoreceptor 7. The cleaning member may be a conductive or insulating fibrous member, rather than a cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

[0086] Figure 3 shows an example of an image forming apparatus that includes a fibrous member 132 (roll-shaped) for supplying lubricant 14 to the surface of the photoreceptor 7, and a fibrous member 133 (flat brush-shaped) for assisting cleaning. These can be arranged as needed.

[0087] The following describes the various components of the image forming apparatus according to this embodiment.

[0088] -Photoreceptor- The photoreceptor 7 has a structure in which, for example, an undercoat layer and a photosensitive layer are laminated in this order on a conductive substrate. The photosensitive layer may be a single-layer photosensitive layer or a multilayer photosensitive layer consisting of a charge generation layer and a charge transport layer.

[0089] -Charging device- The charging device 8 has a charging member according to this embodiment. The charging device 8 may be a charging device in which the charging member is in contact with the surface of the photoreceptor, or a charging device in which the charging member is not in contact with the surface of the photoreceptor. The charging device 8 may be a charging device that applies only a DC voltage to the charging member (DC charging method); a charging device that applies only an AC voltage to the charging member (AC charging method); or a charging device that applies a voltage obtained by superimposing a DC voltage on an AC voltage to the charging member (AC / DC charging method).

[0090] -Exposure equipment- Examples of exposure devices 9 include optical equipment that exposes the surface of a photoreceptor 7 to a predetermined image using light such as semiconductor laser light, LED light, or liquid crystal shutter light. The wavelength of the light source is within the spectral sensitivity range of the photoreceptor. As for semiconductor lasers, near-infrared lasers with an oscillation wavelength of around 780 nm are the mainstream. However, the wavelength is not limited to this, and lasers with oscillation wavelengths in the 600 nm range or blue lasers with oscillation wavelengths between 400 nm and 450 nm may also be used. Furthermore, for color image formation, surface-emitting laser light sources capable of outputting multiple beams are also effective.

[0091] -Developing equipment- Examples of developing devices 11 include general developing devices that develop by contacting or not contacting the developing agent. There are no particular restrictions on the developing device 11 as long as it has the above-described functions, and it can be selected according to the purpose. For example, known developing devices that have the function of applying a one-component or two-component developing agent to the photoreceptor 7 using a brush, roller, etc. Among these, those that use a developing roller that holds the developing agent on its surface are preferred.

[0092] The developer used in the developing device 11 may be a single-component developer consisting of toner alone, The developer may be a two-component system containing toner and carrier. Furthermore, the developer may be magnetic or non-magnetic. Known developers are applicable.

[0093] -Cleaning device- The cleaning device 13 uses a cleaning blade system equipped with a cleaning blade 131. In addition to the cleaning blade system, a fur brush cleaning system or a developing and cleaning system may also be used.

[0094] -Transfer device- Examples of the transfer device 40 include contact-type transfer chargers using belts, rollers, films, rubber blades, etc., and transfer chargers that are known themselves, such as scorotron transfer chargers and corotron transfer chargers that utilize corona discharge.

[0095] -Intermediate Transcript- As the intermediate transfer body 50, a belt-shaped material (intermediate transfer belt) containing semiconducting polyimide, polyamide-imide, polycarbonate, polyarylate, polyester, rubber, etc. is used. In addition to the belt shape, a drum-shaped intermediate transfer body may also be used.

[0096] Figure 4 is a schematic diagram showing another example of an image forming apparatus according to this embodiment. The image forming apparatus 120 shown in Figure 4 is a tandem-type multi-color image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, the four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one photoreceptor is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100, except that it is a tandem type. [Examples]

[0097] The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following explanation, unless otherwise specified, "parts" and "%" refer to mass. In the following descriptions, unless otherwise specified, synthesis, manufacturing, processing, and measurement were performed at room temperature (25°C ± 3°C).

[0098] (Example 1) <Manufacturing of electrostatic materials> -Preparation of support members- A support member with a diameter of 8 mm was prepared, consisting of a cylindrical SUM22 component with a 5 μm thick electroless nickel plating.

[0099] -Formation of the adhesive layer- • Chlorinated polypropylene resin (maleic anhydride chlorinated polypropylene resin, Supercron 930, Nippon Paper Chemical Co., Ltd.): 100 copies • Epoxy resin (EP4000, ADEKA Corporation): 10 parts • Conductive agent: Carbon black (Ketjenblack EC, Ketjenblack International Ltd.): 2.5 parts • Toluene: appropriate amount The above materials were mixed and processed using a ball mill for 1 hour to obtain a resin composition. The resin composition was applied to the surface of the support member by flow coating to form an adhesive layer with a thickness of 10 μm.

[0100] -Formation of the elastic layer- • Epichlorohydrin rubber (product name: EPION301, company name: Daiso): 100 parts by mass, processing aid (product name: Tsubaki, company name: Nippon Oil & Fats Co., Ltd.): 1 part by mass • Carbon black (product name: 3030B, company name: Mitsubishi Chemical Corporation): 1 part by mass Calcium carbonate (product name: Viscoexcel-30, company name: Shiraishi Kogyo Co., Ltd.): 20 parts by mass • Plasticizer (Product name: DB02, Company name: Daiso Co., Ltd.): 3 parts by mass Sulfur (product name: Noxellar DM, company name: Ouchi Shinko Chemical Co., Ltd.): 6 parts by mass • Vulcanization accelerator (product name: Zinc Oxide 2 types, company name: Seido Chemical Co., Ltd.) 5 parts by mass An unvulcanized rubber composition was obtained by kneading the rubber material containing the above-mentioned materials using a closed-type kneader and a roll machine. The rubber composition was kneaded in an open roll and molded into a roll shape using an extruder having a land portion with the shape shown in Table 1 on the surface of the adhesive layer. Next, it was heated in a heating furnace at 170°C for 60 minutes to obtain an elastic layer. The elastic layer was polished to obtain a conductive elastic roll with a diameter of 12 mm. The Mooney viscosity of the elastic layer, according to JIS K6300-1 (2001), was 45.

[0101] -Formation of the surface layer- • Resin: N-methoxymethylated nylon (F30K, Nagase ChemteX Corporation): 80 parts • Resin: Polyvinyl butyral (Eslec BL-1, Sekisui Chemical Co., Ltd.): 20 parts • Conductive particles: Carbon black (MONAHRCH 1000, Cabot): 12 parts • Non-conductive particles: Porous polyamide particles (ORGASOL 2001UD Nat1, Arkema): 8 parts • Additive: Dimethylpolysiloxane (BYK-307, BIC Chemie Japan Co., Ltd.): 0.8 parts The above materials were mixed, diluted with methanol / 1-propanol, and dispersed in a bead mill. The resulting dispersion was immersed and coated onto the surface of a conductive elastic roll in an environment of 24°C and 45% relative humidity, and then heated and dried at 145°C for 30 minutes to form a surface layer with a thickness of 10 μm. Thus, the charged member of Example 1 was obtained.

[0102] <Method for measuring the maximum value of layer thickness variation from the approximate crown curve of the elastic layer> The outer diameter of the elastic layer was evaluated (measured). A light-shielding laser outer diameter measuring device (ROLL2000, manufactured by Asaka Riken Co., Ltd.) was used to measure the outer diameter of the elastic layer. Specifically, both ends of the elastic layer to be measured were supported, and the profile of the outer circumference of the elastic layer from one end to the other in the axial direction was measured. This measurement was performed at 15° intervals in the circumferential direction of the elastic layer. The error relative to the approximate crown curve (radius) was then calculated, and the largest value among the errors was defined as the maximum error.

[0103] <Suppression of uneven concentration> If the maximum error is less than 5 μm, the density unevenness grade will fall within the acceptable range when this rubber roll is used as a charging roll in an electrophotographic image forming apparatus, so it was rated "A". On the other hand, if the maximum error is between 5 μm and 10 μm, the density unevenness grade will fall within the acceptable range, but density unevenness that can be seen with the naked eye may be observed, so it was rated "B". Furthermore, if the maximum error is 10 μm or more, the possibility that the density unevenness grade will not fall within the acceptable range when this rubber roll is used as a charging roll in an electrophotographic image forming apparatus increases, so it was rated "C".

[0104] (Examples 2 to 9, and Comparative Examples 1 to 6) A charged member was fabricated and evaluated in the same manner as in Example 1, except that the thickness of the elastic layer, the shape of the land portion, and the content of the filler were changed as shown in Table 1. The evaluation results are shown in Table 1. In Example 9, Shiratsuka CC (calcium carbonate particles, manufactured by Shiraishi Kogyo Co., Ltd., particle size 50 nm) was used as the filler.

[0105] [Table 1]

[0106] From the above results, it can be seen that the charging member of the example is superior in suppressing density unevenness in the resulting image compared to the charging member of the comparative example.

[0107] (((1))) A charger comprising a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is a non-abrasive surface, the elastic layer contains a rubber material and a filler, the filler content is 15% by mass or more and 40% by mass or less of the total mass of the rubber material, and the maximum value of the variation in layer thickness from the approximate crown curve of the elastic layer is less than 10 μm. (((2))) The electrostatic member according to (((1))), wherein the content of the filler is 15% by mass or more and 25% by mass or less with respect to the total mass of the rubber material. (((3))) The electrostatic member according to (((1))) or (((2))) wherein the rubber material comprises an epichlorohydrin-based rubber. (((4))) The charging member according to any one of (((1))) to (((3))) wherein the elastic layer further comprises a conductive agent. (((5))) The charging member according to any one of (((1))) to (((4))) wherein the Mooney viscosity of the elastic layer is 30 or more and 60 or less. A charging device having a charging member as described in any one of (((6))) (((1))) to (((5))). (((7))) A process cartridge that is attached to and detached from an image forming apparatus, comprising a photoreceptor and a charging device having a charging member described in any one of (((1))) to (((5))) for charging the photoreceptor. (((8))) An image forming apparatus comprising: a photoreceptor; a charging device having a charging member described in any one of (((1))) to (((5))) for charging the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged photoreceptor; a developing device for developing the electrostatic latent image formed on the surface of the photoreceptor with a developer containing toner to form a toner image; and a transfer device for transferring the toner image to the surface of a recording medium. (((9))) A manufacturing apparatus for a charged member according to any one of (((1))) to (((5))), comprising: an extrusion section having an extrusion die for extruding unvulcanized rubber material into a cylindrical shape; and a core supply section for supplying a core to the center of the cylindrically extruded rubber material in order to cover the outer surface of the core with the rubber material, wherein the inner diameter of the extrusion die does not change in the direction of the extrusion of the rubber material along the extrusion direction of the rubber material, and has a land section through which the cylindrical rubber material with the core fed to the center passes in the extrusion direction, and when the thickness of the elastic layer of the resulting molded product is S and the flow path width of the land section is T, the relationship 108% ≤ (T / S) ≤ 112% is satisfied. (((10))) A manufacturing apparatus for a charged member as described in (((9))), where L is the length of the land portion in the extrusion direction, and the relationship 200% ≤ (L / S) ≤ 400% is satisfied. (((1))) A method for manufacturing a charged member according to any one of (((1))) to (((5))), comprising: a first step of supplying a core to the center of the unvulcanized rubber material extruded in a cylindrical shape from an extrusion die in an extrusion section having an extrusion die, and covering the outer surface of the core with the rubber material; and a second step of performing a vulcanization treatment on the rubber material that has covered the outer surface of the core, wherein the inner surface of the extrusion die has an inner diameter that does not change in the direction of the extrusion of the rubber material along the extrusion direction of the rubber material, and has a land portion through which the cylindrical rubber material with the core fed to the center passes in the extrusion direction, and when the thickness of the elastic layer of the obtained molded product is S and the flow path width of the land portion is T, the relationship 108% ≤ (T / S) ≤ 112% is satisfied. (((12))) A method for manufacturing a charged member according to (((11))) in which the relationship 200% ≤ (L / S) ≤ 400% is satisfied when the length of the land portion in the extrusion direction is L.

[0108] According to (((1))), (((3))), or (((4))), a charging member is provided that has a support member and an elastic layer provided on the support member, wherein the surface of the elastic layer is an unpolished surface, the elastic layer contains a rubber material and a filler, the filler content is less than 15% by mass or more than 40% by mass of the total mass of the rubber material, or the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer is 10 μm or more, compared to a case in which the resulting image density unevenness is suppressed. According to (((2))), a charging member is provided that is superior in suppressing density unevenness in the resulting image compared to cases where the content of the filler is less than 15% by mass or more than 25% by mass relative to the total mass of the rubber material. According to (((5))), a charging member is provided that is superior in suppressing density unevenness in the resulting image compared to cases where the Mooney viscosity of the elastic layer is less than 30 or greater than 60. According to (((6))), (((7))), or (((8))), a charging device, process cartridge, or image forming apparatus is provided that has a charging member having a support member and an elastic layer provided on the support member, the surface of the elastic layer being a non-abrasive surface, the elastic layer containing a rubber material and a filler, the filler content being less than 15% by mass or more than 30% by mass of the total mass of the rubber material, or the maximum value of the layer thickness variation from the approximate crown curve of the elastic layer being 10 μm or more, which results in superior suppression of density unevenness in the resulting image. According to (((9))), when the thickness of the elastic layer of the obtained molded product is S and the width of the flow path in the land portion is T, a manufacturing apparatus for a charged member is provided that is superior in suppressing density unevenness of the obtained image compared to the case where the relationship 108% ≤ (T / S) ≤ 112% is not satisfied. According to (((10))), a manufacturing apparatus for a charged member is provided that is superior in suppressing density unevenness in the resulting image compared to the case where the relationship 200% ≤ (L / S) ≤ 400% is not satisfied when the length of the land portion in the extrusion direction is L. According to (((11))), a method for manufacturing a charged member is provided that is superior in suppressing density unevenness in the resulting image compared to the case where the relationship 108% ≤ (T / S) ≤ 112% is not satisfied, when the thickness of the elastic layer of the resulting molded product is S and the width of the flow channel in the land portion is T. According to (((12))), a method for manufacturing a charged member is provided that is superior in suppressing density unevenness in the resulting image compared to the case where the relationship 200% ≤ (L / S) ≤ 400% is not satisfied when the length of the land portion in the extrusion direction is L. [Explanation of symbols]

[0109] 10 Manufacturing apparatus for electrostatically charged components, 14 Pressing machine, 22 Core metal, 56 Rubber roll section, 58 Intermediate section

[0110] 7 Photoreceptor, 8 Charging device, 9 Exposure device, 11 Developing device, 13 Cleaning device, 14 Lubricant, 40 Transfer device, 50 Intermediate transfer body, 100 Image forming device, 120 Image forming device, 131 Cleaning blade, 132 Fibrous material (roll type), 133 Fibrous material (flat brush type), 300 Process cartridge

Claims

1. It comprises a support member and an elastic layer provided on the support member, The surface of the elastic layer is an unpolished surface. The elastic layer comprises a rubber material and a filler. The content of the filler is 15% by mass or more and 40% by mass or less, based on the total mass of the rubber material. The maximum variation in layer thickness from the approximate crown curve of the elastic layer is less than 10 μm. Electrostatic component.

2. The electrostatic member according to claim 1, wherein the content of the filler is 15% by mass or more and 25% by mass or less with respect to the total mass of the rubber material.

3. The charging member according to claim 1, wherein the rubber material includes an epichlorohydrin-based rubber.

4. The charging member according to claim 1, wherein the elastic layer further comprises a conductive agent.

5. The charging member according to claim 1, wherein the Mooney viscosity of the elastic layer is 30 or more and 60 or less.

6. A charging device having a charging member according to any one of claims 1 to 5.

7. Photoreceptor and A charging device comprising a charging member according to any one of claims 1 to 5, for charging the photoreceptor, A process cartridge that is attached to and detached from an image forming apparatus.

8. Photoreceptor and A charging device having a charging member according to any one of claims 1 to 5, for charging the photoreceptor, An electrostatic latent image forming apparatus for forming an electrostatic latent image on the surface of the charged photoreceptor, A developing apparatus that develops an electrostatic latent image formed on the surface of a photoreceptor using a developer containing toner to form a toner image, A transfer device for transferring the toner image onto the surface of a recording medium, An image forming apparatus equipped with the following features.

9. An extrusion section having an extrusion die for extruding unvulcanized rubber material into a cylindrical shape, The system includes a core supply unit that supplies the core to the center of the rubber material, which is extruded into a cylindrical shape, in order to cover the outer surface of the core with the rubber material, The inner circumferential surface of the extrusion die has an inner diameter that does not change in the direction of extrusion of the rubber material, and has a land portion through which a cylindrical rubber material with a core metal inserted into the center passes in the extrusion direction. A manufacturing apparatus for a charged member according to any one of claims 1 to 5, wherein the relationship 108% ≤ (T / S) ≤ 112% is satisfied when S is the thickness of the elastic layer of the obtained molded product and T is the width of the flow path in the land portion.

10. The apparatus for manufacturing a charged member according to claim 9, wherein the relationship 200% ≤ (L / S) ≤ 400% is satisfied when the length of the land portion in the extrusion direction is L.

11. A first step involves supplying a core metal to the center of the unvulcanized rubber material, which is extruded in a cylindrical shape from the extrusion die of an extrusion section having an extrusion die, and covering the outer surface of the core metal with the rubber material. The process includes a second step of applying a vulcanization treatment to the rubber material covering the outer surface of the core metal, The inner circumferential surface of the extrusion die has an inner diameter that does not change in the direction of extrusion of the rubber material, and has a land portion through which a cylindrical rubber material with a core metal inserted into the center passes in the extrusion direction. A method for manufacturing a charged member according to any one of claims 1 to 5, where S is the thickness of the elastic layer of the obtained molded product and T is the width of the flow path in the land portion, and the relationship 108% ≤ (T / S) ≤ 112% is satisfied.

12. A method for manufacturing a charged member according to claim 11, wherein the relationship 200% ≤ (L / S) ≤ 400% is satisfied when the length of the land portion in the extrusion direction is L.

Images