Charging member, charging device, process cartridge, and image forming apparatus

Abstract

The invention discloses a charging member, a charging device, a process cartridge, and an image forming apparatus, the charging member having a support member, an elastic layer provided on the support member, and a surface layer provided on the elastic layer, the surface layer containing a resin, conductive particles, and non-conductive inorganic particles, the surface layer contains 5 parts by mass or more and 40 parts by mass or less of the non-conductive inorganic particles with respect to 100 parts by mass of the resin.

Description

Technical Field

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

[0002] In Japanese Unexamined Patent Application Publication No. 2001-005262, there is disclosed a charging member having a conductive support, a semiconductive elastic layer, and a protective layer, and the protective layer is a polyamide resin, a fluororesin, a polyvinyl butyral resin, or a polyester resin.

[0003] In Japanese Unexamined Patent Application Publication No. 2010-113177, there is disclosed a conductive roller having a shaft body, an elastic layer, and a surface layer, which contacts a body to be charged in a state where a voltage is applied thereto to charge the body to be charged. Among them, the surface layer of the conductive roller has insulating particles, and at least two or more of the insulating particles are overlapped and arranged in the thickness direction of the surface layer. The insulating particles are 12 nylon particles.

[0004] In Japanese Unexamined Patent Application Publication No. 2019-219498, there is disclosed a conductive roller including a core material, a rubber base material, and a surface layer, and the surface layer includes a conductive matrix and insulating particles dispersed in the conductive matrix, and the particles include large particles and small particles. Summary of the Invention

[0005] An object of the present invention is to provide a charging member that is less likely to cause density unevenness in an image and less likely to cause cracks on the surface compared to a charging member in which a surface layer contains less than 5 parts by mass or more than 40 parts by mass of non-conductive inorganic particles with respect to 100 parts by mass of a resin.

[0006] According to a first aspect of the present invention, there is provided a charging member having: a support member; an elastic layer provided on the support member; and a surface layer provided on the elastic layer, the surface layer containing a resin, conductive particles, and non-conductive inorganic particles, and the surface layer containing 5 parts by mass or more and 40 parts by mass or less of the non-conductive inorganic particles with respect to 100 parts by mass of the resin.

[0007] According to a second aspect of the present invention, in the charging member based on the first aspect, the non-conductive inorganic particles have a thermal conductivity of 40 W / (m·K) or more.

[0008] According to a third aspect of the present invention, in the charging member based on the first or second aspect, the non-conductive inorganic particles include at least one selected from the group consisting of nitride particles, oxide particles, carbide particles, and boride particles.

[0009] According to a fourth aspect of the present invention, in the charging member based on any one of the first to third aspects, the non-conductive inorganic particles include at least one selected from the group consisting of aluminum nitride particles, boron nitride particles, and magnesium oxide particles.

[0010] According to a fifth aspect of the present invention, in the charging member based on any one of the first to fourth aspects, the average primary particle diameter of the non-conductive inorganic particles is 5 μm or more and 20 μm or less.

[0011] According to a sixth aspect of the present invention, there is provided a charging device having the charging member based on any one of the first to fifth aspects.

[0012] According to a seventh aspect of the present invention, there is provided a processing cartridge including: a photoreceptor; and a charging device having the charging member based on any one of the first to fifth aspects to charge the photoreceptor, the processing cartridge being detachably attachable to an image forming apparatus.

[0013] According to an eighth aspect of the present invention, there is provided an image forming apparatus including: a photoreceptor; a charging device having the charging member based on any one of the first to fifth aspects to charge the photoreceptor; an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged photoreceptor; a developing device that develops the electrostatic latent image formed on the surface of the photoreceptor using a developer containing toner to form a toner image; and a transfer device that transfers the toner image onto the surface of a recording medium.

[0014] (Effect)

[0015] According to the first, third, or fourth aspect, there is provided a charging member that is less likely to cause density unevenness in an image and is less likely to have cracks on the surface compared to a charging member in which the surface layer contains less than 5 parts by mass or more than 40 parts by mass of non-conductive inorganic particles relative to 100 parts by mass of the resin.

[0016] According to the second aspect, there is provided a charging member that is less likely to cause density unevenness in an image and is less likely to have cracks on the surface compared to a charging member in which the thermal conductivity of the non-conductive inorganic particles contained in the surface layer is less than 40 W / (m·K).

[0017] According to the fifth aspect, there is provided a charging member that is less likely to have cracks on the surface compared to a charging member in which the average particle diameter of the non-conductive inorganic particles contained in the surface layer exceeds 20 μm.

[0018] According to the sixth aspect, there is provided a charging device including a charging member which is less likely to cause density unevenness in an image and less likely to cause cracks on the surface as compared with a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass based on 100 parts by mass of the resin.

[0019] According to the seventh aspect, there is provided a processing cartridge including a charging member which is less likely to cause density unevenness in an image and less likely to cause cracks on the surface as compared with a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass based on 100 parts by mass of the resin.

[0020] According to the eighth aspect, there is provided an image forming apparatus including a charging member which is less likely to cause density unevenness in an image and less likely to cause cracks on the surface as compared with a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass based on 100 parts by mass of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic perspective view showing an example of the charging member of the present embodiment;

[0022] Figure 2 is a schematic cross-sectional view showing an example of the charging member of the present embodiment, which is a Figure 1 cross-sectional view taken along line A-A;

[0023] Figure 3 is a schematic structural view showing an example of the image forming apparatus of the present embodiment;

[0024] Figure 4 is a schematic structural view showing another example of the image forming apparatus of the present embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Embodiments of the present invention will be described below. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

[0026] In the present invention, "A and / or B" is synonymous with "at least one of A and B". That is, "A and / or B" may refer only to A, may refer only to B, or may refer to a combination of A and B.

[0027] In the present invention, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0028] Within the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described within a numerical range may also be replaced with the upper limit value or the lower limit value of other stepwise described numerical ranges. Additionally, within the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range may also be replaced with the value shown in the examples.

[0029] In the present invention, the term "process" not only refers to an independent process, but also includes this term even when it cannot be clearly distinguished from other processes, as long as the purpose of the process can be achieved.

[0030] In the present invention, when describing an embodiment with reference to the accompanying drawings, the structure of the embodiment is not limited to the structure shown in the drawings. Additionally, the sizes of the components in each drawing are conceptual sizes, and the relative relationship of the sizes between the components is not limited to this.

[0031] In the present invention, each component may also include multiple corresponding substances. In the present invention, when referring to the amount of each component in a composition, in the case where there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition.

[0032] In the present invention, multiple particles corresponding to each component may also be included. In the case where there are multiple particles corresponding to each component in the composition, unless otherwise specified, the particle size of each component refers to a value related to the mixture of the multiple particles present in the composition.

[0033] In the present invention, the "axial direction" of the charging member refers to the direction in which the rotation axis of the charging member extends, and the "circumferential direction" of the charging member refers to the rotation direction of the charging member.

[0034] <Charging Member>

[0035] The charging member of the present embodiment has a support member, an elastic layer provided on the support member, and a surface layer provided on the elastic layer. The surface layer is the outermost layer of the charging member of the present embodiment.

[0036] Figure 1 It is a schematic perspective view showing an example of the charging member of the present embodiment. Figure 2 Is Figure 1 The A-A cross-sectional view of, which is cut along the radial direction Figure 1 The cross-sectional view of the illustrated charging member.

[0037] Figure 1The charging member 30 shown is a roll-shaped charging member. The charging member 30 has a structure in which an elastic layer 34 and a surface layer 36 are sequentially stacked on a support member 32. The charging member 30 may also have an adhesive layer (not shown) between the support member 32 and the elastic layer 34 and / or between the elastic layer 34 and the surface layer 36. The surface layer 36 is the outermost layer of the charging member 30.

[0038] The shape of the charging member of the present embodiment is not limited to a roll shape, and may also be a strip shape, a tubular shape, a blade shape, etc.

[0039] Regarding the charging member of the present embodiment, the surface layer contains a resin, conductive particles, and non-conductive inorganic particles, and the surface layer contains 5 parts by mass or more and 40 parts by mass or less of non-conductive inorganic particles with respect to 100 parts by mass of the resin.

[0040] With the above structure, the charging member of the present embodiment is less likely to cause density unevenness in the image and is less likely to generate cracks on the surface. The reasons are speculated as follows.

[0041] When image formation is performed for a long time, dirt gradually accumulates on the surface of the charging member. This dirt mainly originates from toner. Dirt on the surface of the charging member is likely to occur in a charging member that contacts the surface of the photoreceptor, and sometimes also occurs in a charging member that does not contact the surface of the photoreceptor due to electrostatic adsorption of toner.

[0042] Moreover, when continuous image formation is performed, the temperature of the charging member rises, and a chemical reaction occurs between the components of the surface layer of the charging member and the components derived from the toner, and contaminants adhere to the surface of the charging member to form a contaminated layer. Due to this contaminated layer, discharge unevenness occurs in the charging member, and density unevenness occurs in the image. In addition, because the contaminated layer is relatively fragile, cracks are likely to occur, and sometimes cracks in the contaminated layer become the starting point and cracks also occur in the charging member.

[0043] In view of the above phenomena, in order to improve the heat dissipation of the charging member, the charging member of the present embodiment contains inorganic particles, which are particles with excellent thermal conductivity, in the surface layer. The inorganic particles contained in the surface layer for heat conduction are non-conductive, so that even if the content is relatively large, it does not affect the electrical characteristics of the charging member.

[0044] The surface layer containing non-conductive inorganic particles suppresses the temperature rise of the charging member due to its excellent heat dissipation. As a result, the chemical reaction between the components of the surface layer of the charging member and the components derived from the toner and the formation of the contaminated layer are suppressed. Therefore, the charging member of the present embodiment is less likely to cause density unevenness in the image and is less likely to generate cracks on the surface.

[0045] In the present invention, the difference between the non-conductivity and conductivity of the particles contained in the surface layer is that the volume resistivity is 1×108 Particles with a volume resistivity of 1 Ω·cm or more are non-conductive particles, and particles with a volume resistivity lower than 1×10 8 Ω·cm are conductive particles.

[0046] The method for measuring the volume resistivity of the particles contained in the surface layer is as follows.

[0047] Fill the particles to be measured into the sample holder of the powder resistance measuring device, and apply a compressive load of 20 kN. The measurement is carried out at a temperature of 23°C and a relative humidity of 50% under an applied voltage of 90 V and a load of 4 kN.

[0048] The particles to be measured are particles used as the material for forming the surface layer or particles taken out from the surface layer. The method for taking out particles from the surface layer is not limited. Such methods are, for example, the following: dipping the surface layer peeled from the charging member in an organic solvent that dissolves the adhesive resin, dissolving the adhesive resin with the organic solvent, and taking out the particles; heating the surface layer peeled from the charging member to a high temperature to make the adhesive resin disappear and taking out the particles.

[0049] Regarding the charging member of the present embodiment, the content of non-conductive inorganic particles in the surface layer is 5 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the resin.

[0050] From the viewpoints of the thermal conductivity and heat dissipation of the surface layer, the content of non-conductive inorganic particles in the surface layer is 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 15 parts by mass or more relative to 100 parts by mass of the resin.

[0051] From the viewpoint that cracks are not easily generated in the surface layer, the content of non-conductive inorganic particles in the surface layer is 40 parts by mass or less, preferably 30 parts by mass or less, and more preferably 25 parts by mass or less.

[0052] Regarding the charging member of the present embodiment, from the viewpoint of suppressing the generation of a contamination layer on the surface of the charging member, the thermal conductivity from the lower surface of the elastic layer to the upper surface of the surface layer is preferably 0.4 W / (m·K) or more, more preferably 0.5 W / (m·K) or more, and further preferably 0.6 W / (m·K) or more.

[0053] The thermal conductivity from the lower surface of the elastic layer to the upper surface of the surface layer can be, for example, 5.0 W / (m·K) or less, 4.0 W / (m·K) or less, 3.0 W / (m·K) or less.

[0054] The method for measuring the thermal conductivity of the charging member from the lower surface of the elastic layer to the upper surface of the surface layer is as follows.

[0055] All layers from the elastic layer to the surface layer are cut out from the central part of the axial direction of the charging member with an axial length of 5 mm × a circumferential length of 2 mm, and used as a specimen. At room temperature (25 °C ± 3 °C), the thermal diffusivity in the thickness direction (i.e., the direction from the lower surface of the elastic layer toward the upper surface of the surface layer) is measured using a thermal diffusivity measuring device (FOX50, manufactured by Waters Corporation). The thermal conductivity (W / (m·K)) is calculated by multiplying the thermal diffusivity by the specific heat and density.

[0056] The method for measuring the specific heat is as follows.

[0057] After cutting out all layers from the elastic layer to the surface layer from the central part of the axial direction of the charging member with an axial length of 5 mm × a circumferential length of 2 mm, the axial length and the circumferential length are adjusted so that the mass of the specimen is 25 mg, and it is used as a specimen. In accordance with JIS K 7123:2012, measurement is performed using an input compensation differential scanning calorimeter (Diamond DSC, manufactured by ParkinElmer), and the specific heat is calculated.

[0058] The method for measuring the density is as follows.

[0059] All layers from the elastic layer to the surface layer are cut out from the central part of the axial direction of the charging member with an axial length of 5 mm × a circumferential length of 2 mm, and used as a specimen. The density is measured using a dry density measuring device (AccuPyc II 1340, manufactured by Micrometrics).

[0060] Hereinafter, each layer of the charging member will be described in detail.

[0061] [Support member]

[0062] The support member is a conductive member that functions as an electrode and a support for the charging member. The support member may be a hollow member or a non-hollow member, and is, for example, a rod-shaped, cylindrical, or endless belt-shaped member.

[0063] Examples of the support member include metal members such as iron (free-cutting steel, etc.), copper, copper alloy, brass, stainless steel, aluminum, and nickel; iron members plated with chromium, nickel, etc.; members obtained by plating the outer peripheral surface of resin or ceramic members; resin or ceramic members containing a conductive agent, etc.

[0064] [Elastic layer]

[0065] Preferably, the elastic layer has conductivity, and the volume resistivity at 20 °C is 1 × 10 3 Ω·cm or more and 1 × 10 14 Ω·cm or less.

[0066] The volume resistivity of the elastic layer is the value measured by the following method.

[0067] After removing the surface layer of the charging member by grinding, an elastic layer is cut out from the axial center part of the charging member with an axial length of 25 mm and a circumferential length of 8 mm and used as a specimen. Measure the thickness of the specimen (i.e., the elastic layer). In accordance with JIS K 6911:1995, using a measuring jig (R12702A / B resistor box: manufactured by Advantest Corporation) and a high-resistance measuring device (R8340A digital high-resistance / microammeter: manufactured by Advantest Corporation), apply a voltage to the specimen for 30 seconds to adjust the electric field (applied voltage / sheet thickness of the composition) to 1000 V / cm. Read the current value and calculate using the following formula.

[0068] Volume resistivity (Ω·cm) = (specimen area (cm 2 2) × applied voltage (V)) / (current value (A) × specimen thickness (cm))

[0069] The elastic layer can be a foamed elastic layer or a non-foamed elastic layer. The elastic layer can be directly disposed on the outer peripheral surface of the support member or can be disposed on the outer peripheral surface of the support member via an adhesive layer.

[0070] An example of an embodiment of the elastic layer includes an elastic material, a conductive agent, and other additives.

[0071] Examples of the elastic material include polyurethane, nitrile rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, epichlorohydrin rubber, epichlorohydrin-ethylene oxide rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether rubber, styrene-butadiene rubber, acrylonitrile-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 them. 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 them are also preferred.

[0072] Examples of the conductive agent include an electronic conductive agent and an ionic conductive agent. Examples of the electronic conductive agent include carbon blacks such as furnace black, thermal black, channel black, Ketjen black, acetylene black, and pigment 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 powders of substances obtained by subjecting the surface of an insulating material to conductivity treatment. Examples of the ionic conductive agent 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. The conductive agent may be used alone or in combination of two or more.

[0073] The total content of the conductive agent contained in the elastic layer is preferably set based on the volume resistivity of the elastic layer.

[0074] When an electronic conductive agent is used as the conductive agent, for example, the total amount of the electronic conductive agent may be 1 part by mass or more and 20 parts by mass or less, or may be 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the elastic material.

[0075] When an ionic conductive agent is used as the conductive agent, for example, the total amount of the ionic conductive agent may be 0.1 part by mass or more and 10 parts by mass or less, or may be 0.5 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the elastic material.

[0076] The average primary particle diameter of the conductive agent is preferably 1 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less. The average primary particle diameter of the conductive agent is determined by the following method: observing the cross-section of the elastic layer using an electron microscope, measuring the major axis of 100 conductive agents, and calculating the arithmetic average thereof.

[0077] As the conductive agent, carbon black is preferred. The average primary particle diameter of the carbon black is preferably 1 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less.

[0078] The content of the carbon black is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 3 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the elastic material.

[0079] Examples of other additives include a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerating aid, a filler, a softening agent, a plasticizer, a curing agent, an antioxidant, a surfactant, and a coupling agent.

[0080] Examples of the filler include calcium carbonate, silica, and clay minerals. The filler may be used alone or in combination of two or more.

[0081] As the filler, calcium carbonate is preferred. The content of calcium carbonate is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 40 parts by mass or less, relative to 100 parts by mass of the elastic material.

[0082] The layer thickness of the elastic layer is preferably 5 mm or more and 20 mm or less, more preferably 10 mm or more and 15 mm or less.

[0083] The layer thickness of the elastic layer is measured by photographing the cross-section of the elastic layer with an electron microscope. The value obtained by measuring four places at 90° increments in the circumferential direction at the axial center of the charging member and taking the arithmetic mean is used as the layer thickness of the elastic layer.

[0084] As a method for forming the elastic layer on the support member, for example, there can be mentioned: a method of extruding a composition for forming an elastic layer, which is a mixture of an elastic material, a conductive agent, and other additives, together with a cylindrical support member from an extrusion molding machine, forming a layer of the composition for forming an elastic layer on the outer peripheral surface of the support member, and then heating the layer of the composition for forming an elastic layer to cause a cross-linking reaction (including vulcanization) to form the elastic layer; a method of extruding a composition for forming an elastic layer, which is a mixture of an elastic material, a conductive agent, and other additives, from an extrusion molding machine onto the outer peripheral surface of an endless belt-shaped support member, forming a layer of the composition for forming an elastic layer on the outer peripheral surface of the support member, and then heating the layer of the composition for forming an elastic layer to cause a cross-linking reaction (including vulcanization) to form the elastic layer, etc. The support member may also have an adhesive layer on its outer peripheral surface.

[0085] [Adhesive layer]

[0086] An adhesive layer for bonding the two may also be present between the support member and the elastic layer.

[0087] Specific examples of the adhesive layer between the support member and the elastic layer include layers containing resins such as polyolefin resin, acrylic resin, epoxy resin, polyurethane, nitrile rubber, chloroprene rubber, vinyl chloride resin, vinyl acetate resin, polyester resin, phenol resin, and silicone resin. The adhesive layer may also contain a conductive agent (for example, the above-mentioned electron conductive agent or ion conductive agent).

[0088] From the viewpoint of the adhesion between the elastic layer and the support member, the layer thickness of the adhesive layer is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 40 μm or less, and further preferably 5 μm or more and 20 μm or less.

[0089] The layer thickness of the adhesive layer is measured by photographing the cross-section with an electron microscope. The value obtained by measuring four places at 90° increments in the circumferential direction at the axial center of the charging member and taking the arithmetic mean is used as the layer thickness of the adhesive layer.

[0090] [Surface layer]

[0091] The surface layer has conductivity, and the volume resistivity at 20 °C is preferably 1×10 3 Ω·cm or more and 1×10 14 Ω·cm or less. The volume resistivity of the surface layer is the value measured by the following method.

[0092] The layer thickness of the surface layer is measured by the measurement method described below. The support member of the charging member is set as the cathode, and an aluminum plate with a width of 1.5 cm wound around the surface layer once is set as the anode. Use SI 1260 impedance / gain phase analyzer (TOYO Corporation) as the power supply and ammeter, and use 1296 dielectric interface (TOYO Corporation) as the current amplifier. Apply an AC voltage of 1 Vp-p from the high-frequency side at a frequency from 1 kHz to 0.01 Hz. The resistance component of the impedance in the range from 100 Hz to 0.1 Hz is obtained as the volume resistance value of the surface layer. The volume resistivity of the surface layer is calculated by the following formula.

[0093] Volume resistivity (Ω·cm) = Volume resistance (Ω) × Area of the anode (cm 2 ) / Layer thickness of the surface layer (cm)

[0094] The surface layer contains a resin, conductive particles, and non-conductive inorganic particles.

[0095] Examples of the resin include copolymerized nylon resin, polyamide resin, polyimide resin, polyamideimide resin, polyvinyl butyral resin, polyester resin, polyethylene terephthalate resin, polyarylate resin, polycarbonate resin, polyethylene resin, polyurethane resin, phenol 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 copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, fluororubber, polyethylene resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinylidene chloride resin, polyvinyl chloride resin, ethylene-vinyl acetate copolymer resin, cellulose, polythiophene resin, a mixture of two or more of them, a resin obtained by curing or crosslinking at least one of them with a curing agent or catalyst, etc. The resin can be used alone or in combination of two or more.

[0096] From the viewpoint of suppressing contamination of the surface layer, the resin contained in the surface layer is preferably a polyamide resin, a polyvinylidene fluoride resin, or a tetrafluoroethylene resin, more preferably a polyamide resin. As the polyamide, from the viewpoint of suppressing contamination of the surface layer, an alcohol-soluble polyamide is preferred, an alkoxymethylated polyamide (such as alkoxymethylated nylon) is more preferred, and a methoxymethylated polyamide (such as methoxymethylated nylon) is further preferred.

[0097] From the viewpoint of the adhesiveness of the non-conductive inorganic particles, the surface layer preferably contains a polyvinyl butyral resin.

[0098] An example of the embodiment of the surface layer contains a polyamide resin and a polyvinyl butyral resin as the adhesive resin. In this case, the mass ratio of the two is preferably polyamide resin: polyvinyl butyral resin = 95:5 to 65:35, more preferably 90:10 to 70:30, and further preferably 85:15 to 75:25.

[0099] Examples of the conductive particles include carbon black; metal oxides such as tin oxide, titanium oxide, and zinc oxide. As the conductive particles contained in the surface layer, carbon black is preferred. The conductive particles can be used alone or in combination of two or more.

[0100] Regarding the conductive particles contained in the surface layer, from the viewpoint of excellent dispersibility in the resin, the average primary particle diameter is preferably 10 nm or more and 50 nm or less.

[0101] The average primary particle diameter of the conductive particles is determined by the following method: observing the cross-section of the surface layer with an electron microscope, measuring the major axis of 100 conductive particles, and calculating the arithmetic mean.

[0102] The content of the conductive particles contained in the surface layer is preferably 5 parts by mass or more and 50 parts by mass or less, more preferably 8 parts by mass or more and 40 parts by mass or less, and further preferably 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the resin.

[0103] In order to improve the heat dissipation of the charging component, the surface layer contains non-conductive inorganic particles. The thermal conductivity of the non-conductive inorganic particles is preferably 20 W / (m·K) or more, more preferably 30 W / (m·K) or more, and further preferably 40 W / (m·K) or more.

[0104] The thermal conductivity of the non-conductive inorganic particles can be, for example, 150 W / (m·K) or less, 120 W / (m·K) or less, or 100 W / (m·K) or less.

[0105] The method for measuring the thermal conductivity of non-conductive inorganic particles is measured in accordance with JIS R1611:2010 "Method for Measuring Thermal Diffusivity, Specific Heat Capacity, and Thermal Conductivity of Fine Ceramics Based on the Flash Method". The particles to be measured are filled in the specimen 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 carried out in an environment with a temperature of 23 °C and a relative humidity of 50%.

[0106] The non-conductive inorganic particles for measurement are non-conductive inorganic particles as a material for forming the surface layer or non-conductive inorganic particles taken out from the surface layer. There is no limitation on the method for taking out non-conductive inorganic particles from the surface layer. For example, the method is as follows: immersing the surface layer peeled from the charging member in an organic solvent that dissolves the adhesive resin, dissolving the adhesive resin with the organic solvent, and taking out the non-conductive inorganic particles; heating the surface layer peeled from the charging member to a high temperature to make the adhesive resin disappear, and taking out the non-conductive inorganic particles, etc.

[0107] As the non-conductive inorganic particles, from the viewpoint of excellent thermal conductivity, fine ceramic particles are preferred. As the fine ceramic particles, for example, nitride particles, oxide particles, carbide particles, and boride particles can be cited.

[0108] As the nitride particles, for example, particles of aluminum nitride, boron nitride, and silicon nitride can be cited.

[0109] As the oxide particles, for example, particles of magnesium oxide and aluminum oxide can be cited.

[0110] As the carbide particles, for example, particles of silicon carbide can be cited.

[0111] As the boride particles, for example, particles of titanium boride, niobium boride, molybdenum boride, etc. can be cited.

[0112] These particles can be used alone or in combination of two or more.

[0113] As the 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.

[0114] Regarding the non-conductive inorganic particles contained in the surface layer, the average primary particle size is preferably 5 μm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less, and further preferably 5 μm or more and 10 μm or less.

[0115] When the average primary particle size of the non-conductive inorganic particles is 5 μm or more, minute irregularities (i.e., discharge starting points for discharging to the photosensitive layer) can be formed on the surface of the surface layer.

[0116] When the average primary particle diameter of the non-conductive inorganic particles is 20 μm or less, cracks are less likely to occur in the surface layer.

[0117] The average primary particle diameter of the non-conductive inorganic particles is determined by the following method: observing a cross-section of the surface layer using an electron microscope, measuring the major axis of 100 non-conductive inorganic particles, and calculating the arithmetic mean thereof.

[0118] From the viewpoints of excellent heat dissipation of the surface layer and suppression of crack generation, the content of the non-conductive inorganic particles contained in the surface layer is 5 parts by mass or more and 40 parts by mass or less, preferably 10 parts by mass or more and 30 parts by mass or less, more preferably 15 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the resin.

[0119] The surface layer may also contain various additives. Examples of the additives include fillers, softeners, plasticizers, curing agents, antioxidants, coupling agents, surfactants, defoaming agents, leveling agents, and the like.

[0120] The layer thickness of the surface layer is preferably 1 μm or more and 25 μm or less, preferably 3 μm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less.

[0121] The layer thickness of the surface layer is measured by photographing a cross-section using an electron microscope. The value obtained by measuring four locations at 90° increments in the circumferential direction at the axial center of the charging member and calculating the arithmetic mean is used as the layer thickness of the surface layer.

[0122] As a method of forming the surface layer on the elastic layer, for example, a method of coating a surface layer-forming composition obtained by mixing a resin, conductive particles, non-conductive inorganic particles, and other additives on the outer peripheral surface of the elastic layer to form a layer of the surface layer-forming composition, and then drying the layer of the surface layer-forming composition can be cited. As a method of coating the surface layer-forming composition on the outer peripheral surface of the elastic layer, for example, dip coating, roll coating, knife coating, wire bar coating, spraying, slot coating, air knife coating, curtain coating, and the like can be cited.

[0123] <Charging Device, Image Forming Device, Process Cartridge>

[0124] The charging device of the present embodiment includes the charging member of the present embodiment. The charging device of the present embodiment may be a charging device in which the charging member is in contact with the surface of the photoreceptor, or may be a charging device in which the charging member is not in contact with the surface of the photoreceptor. In the charging device in which the charging member is in contact with the surface of the photoreceptor, the effects achieved by the present embodiment (less likely to generate density unevenness in the image and less likely to generate cracks on the surface of the charging member) are remarkable.

[0125] The image forming apparatus according to the present embodiment includes a photoreceptor, a charging device that charges the surface of the photoreceptor, an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the photoreceptor, a developing device that develops the electrostatic latent image formed on the surface of the photoreceptor using a developer containing toner to form a toner image, and a transfer device that transfers the toner image onto the surface of a recording medium. Further, as the charging device, a charging device having the charging member according to the present embodiment is applied. The charging device may be a charging device in which the charging member is in contact with the surface of the photoreceptor, or may be a charging device in which the charging member is not in contact with the surface of the photoreceptor. In the charging device in which the charging member is in contact with the surface of the photoreceptor, the effects achieved by the present embodiment (less likely to cause density unevenness in the image and less likely to cause cracks on the surface of the charging member) are remarkable.

[0126] In the image forming apparatus according to the present embodiment, for example, the portion including the photoreceptor and the charging device may be a cartridge structure detachable from the image forming apparatus (i.e., the processing cartridge according to the present embodiment). In the processing cartridge, in addition to the photoreceptor and the charging device, for example, at least one selected from the group consisting of an electrostatic latent image forming device, a developing device, and a transfer device may be further included. The charging device may be a charging device in which the charging member is in contact with the surface of the photoreceptor, or may be a charging device in which the charging member is not in contact with the surface of the photoreceptor. In the charging device in which the charging member is in contact with the surface of the photoreceptor, the effects achieved by the present embodiment (less likely to cause density unevenness in the image and less likely to cause cracks on the surface of the charging member) are remarkable.

[0127] The image forming apparatus according to the present embodiment is applicable to: an apparatus having a fixing device that fixes the toner image transferred onto the surface of the recording medium; a direct transfer type apparatus that directly transfers the toner image formed on the surface of the photoreceptor onto the recording medium; an intermediate transfer type apparatus that transfers the toner image formed on the surface of the photoreceptor onto the surface of an intermediate transfer member once and transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium twice; an apparatus having a cleaning device that cleans the surface of the photoreceptor before charging after the transfer of the toner image; an apparatus having a discharging device that discharges the photoreceptor by irradiating it with pre-exposure light after the transfer of the toner image; an apparatus having a photoreceptor heating member for raising the temperature of the photoreceptor and lowering the relative humidity, etc., which are well-known image forming apparatuses.

[0128] In the case of an intermediate transfer type apparatus, the transfer device is, for example, applicable to a structure having an intermediate transfer member that transfers the toner image onto the surface, a primary transfer device that transfers the toner image formed on the surface of the photoreceptor onto the surface of the intermediate transfer member once, and a secondary transfer device that transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium twice.

[0129] The image forming apparatus according to the present embodiment may be any one of an image forming apparatus using a dry developing method and an image forming apparatus using a wet developing method (a developing method using a liquid developer).

[0130] The following shows an example of the image forming apparatus according to the present embodiment, but is not limited thereto. The main parts shown in the drawings will be described, and the description of the others will be omitted.

[0131] Figure 3 It is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0132] As Figure 3 shown, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300, an exposure device 9 (an example of an electrostatic latent image forming device), a transfer device 40 (a primary transfer device), and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the photosensitive member 7 can be exposed from the opening of the process cartridge 300, the transfer device 40 is disposed at a position facing the photosensitive member 7 with the intermediate transfer member 50 interposed therebetween, and the intermediate transfer member 50 is disposed such that a part thereof is in contact with the photosensitive member 7. Although not shown, there is also a secondary transfer device that transfers the toner image transferred onto the intermediate transfer member 50 to a recording medium (e.g., paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer device.

[0133] Figure 3 In the process cartridge 300 in, the photosensitive member 7, a charging device 8, a developing device 11, and a cleaning device 13 are integrally supported within a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed in contact with the surface of the photosensitive member 7. The cleaning member may not be in the form of the cleaning blade 131 but may be a conductive or insulating fibrous member, and this cleaning member may be used alone or in combination with the cleaning blade 131.

[0134] In Figure 3 an example is shown in which a fibrous member 132 (in a roll shape) for supplying a lubricant 14 to the surface of the photosensitive member 7 and a fibrous member 133 (in a flat brush shape) for assisting cleaning are provided as the image forming apparatus, but they are arranged as needed.

[0135] Next, each structure of the image forming apparatus according to the present embodiment will be described.

[0136] - Photosensitive member -

[0137] The photoreceptor 7 has, for example, a structure in which an undercoat layer and a photosensitive layer are sequentially laminated on a conductive substrate. The photosensitive layer may be a single-layer photosensitive layer or a laminated photosensitive layer composed of a charge generation layer and a charge transport layer.

[0138] - Charging device -

[0139] The charging device 8 has the charging member of the present embodiment. The charging device 8 may be a charging device in a manner where the charging member is in contact with the surface of the photoreceptor, or a charging device in a manner where the charging member is not in contact with the surface of the photoreceptor. The charging device 8 may be any one of 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), and a charging device that applies a voltage obtained by overlapping an AC voltage on a DC voltage to the charging member (AC / DC charging method).

[0140] - Exposure device -

[0141] As the exposure device 9, for example, an optical system device that exposes light such as semiconductor laser light, LED light, and liquid crystal shutter light onto the surface of the photoreceptor 7 in a set image shape can be cited. The wavelength of the light source is set within the spectral sensitivity region of the photoreceptor. As the wavelength of the semiconductor laser, near-infrared light having an oscillation wavelength of around 780 nm is the mainstream. However, it is not limited to this wavelength, and a laser having an oscillation wavelength in the 600 nm range or a laser having an oscillation wavelength of 400 nm or more and 450 nm or less can also be used as a blue laser. In addition, a surface-emitting type laser light source of a type that can output multiple beams is also effective for forming a color image.

[0142] - Developing device -

[0143] As the developing device 11, for example, a normal developing device that develops by bringing the developer into contact or non-contact can be cited. The developing device 11 is not particularly limited as long as it has the above functions and is selected according to the purpose. For example, a known developer having a function of attaching a one-component developer or a two-component developer to the photoreceptor 7 using a brush, a roller, etc. can be cited. Among them, it is also preferable to use a developing roller that holds the developer on its surface.

[0144] The developer used in the developing device 11 may be a one-component developer containing only toner or a two-component developer containing toner and a carrier. In addition, the developer may be magnetic or non-magnetic. These developers are applicable to known developers.

[0145] - Cleaning device -

[0146] The cleaning device 13 uses a cleaning blade method device equipped with a cleaning blade 131. In addition to the cleaning blade method, a brush cleaning method and a cleaning method during development can also be adopted.

[0147] - Transfer device -

[0148] As the transfer device 40, for example, known transfer chargers such as a contact type transfer charger using a belt, a roller, a film, a rubber blade, etc., a grid corotron transfer charger using corona discharge, or a corotron transfer charger can be cited.

[0149] - Intermediate transfer body -

[0150] As the intermediate transfer body 50, a belt-shaped transfer body (intermediate transfer belt) containing polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc., which is given semi-conductivity, is used. In addition, as a method of the intermediate transfer body, in addition to the belt shape, a drum-shaped transfer body can also be used.

[0151] Figure 4 It is a schematic structural diagram showing another example of the image forming apparatus of the present embodiment.

[0152] Figure 4 The shown image forming apparatus 120 is a multi-color image forming apparatus in a tandem type equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged side by side on the intermediate transfer body 50, and a structure is formed in which one photoreceptor is used for each color. The image forming apparatus 120 has the same structure as the image forming apparatus 100 except for the tandem type.

[0153] [Examples]

[0154] Hereinafter, embodiments of the invention will be described in detail by way of examples, but the embodiments of the invention are not limited to these examples.

[0155] In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0156] In the following description, unless otherwise specified, synthesis, manufacturing, processing, measurement, etc. are carried out at normal temperature (25°C ± 3°C).

[0157] <Manufacture of charging roller>

[0158] [Example 1]

[0159] - Preparation of support member -

[0160] A support member having a diameter of 8 mm obtained by electroless nickel plating with a thickness of 5 μm on a cylindrical member made of SUM22 is prepared.

[0161] - Formation of the Adhesive Layer -

[0162] · Chlorinated polypropylene resin (maleic anhydride chlorinated polypropylene resin, Superchlon930, Nippon Paper Chemicals Co., Ltd.): 100 parts

[0163] · Epoxy resin (EP4000, ADEKA Corporation): 10 parts

[0164] · Conductive agent: Carbon black (Ketjen Black EC, Ketjen Black International Co., Ltd.): 2.5 parts

[0165] · Toluene: Appropriate amount

[0166] Mix the above materials and process them using a ball mill for 1 hour to obtain a resin composition. Brush the resin composition on the surface of the support member to form an adhesive layer with a thickness of 10 μm.

[0167] - Formation of the Elastic Layer -

[0168] · Epichlorohydrin rubber (Gechron3106, Zeon Corporation): 100 parts

[0169] · Electronic conductive agent: Carbon black (Asahi #60, Asahi Carbon Co., Ltd.): 10 parts

[0170] · Ion conductive agent: Benzyltriethylammonium chloride (Lion Corporation): 5 parts

[0171] · Calcium carbonate (Whiton SB, Shiraishi Calcium Co., Ltd.): 20 parts

[0172] · Vulcanizing agent: Sulfur (VULNOC R, Ouchi Shinko Chemical Industry Co., Ltd.): 1 part

[0173] · Vulcanization accelerator: Stearic acid (NOF Corporation): 1 part

[0174] · Vulcanization accelerator: Zinc oxide: 1.5 parts

[0175] Mix the above materials, knead them using a tangential pressure kneader, and pass them through a filter to obtain a rubber composition. Knead the rubber composition using an open mill and form it into a roll shape on the surface of the adhesive layer using a molding machine. Then, heat it in a heating furnace at 175 °C for 70 minutes to obtain an elastic layer. Grind the elastic layer to obtain a conductive elastic roller with a diameter of 14 mm.

[0176] - Formation of the Surface Layer -

[0177] · Resin: N-methoxymethylated nylon (F30K, Nagase ChemteX Corporation): 80 parts

[0178] · Resin: Polyvinyl butyral (S-LEC BL-1, Sekisui Chemical Co., Ltd.): 20 parts

[0179] · Conductive particles: Carbon black (MONAHRCH 1000, Cabot Corporation): 12 parts

[0180] · Non-conductive particles: Aluminum nitride particles (AIN050AW, Thrutek Corporation): 8 parts

[0181] · Additive: Dimethylpolysiloxane (BYK-307, BYK Japan Co., Ltd.): 0.8 parts

[0182] Mix the above materials, dilute with methanol / 1-propanol, and disperse using a bead mill. Immerse and coat the obtained dispersion on the surface of the conductive elastic roller in an environment of 24°C and 45% relative humidity, and heat and dry at 130°C for 30 minutes to form a surface layer with a thickness of 10 μm. Thus, the charging roller of Example 1 is obtained.

[0183] [Comparative Example 1]

[0184] The same as Example 1, however, the non-conductive particles were changed to polyamide particles (Orgasol, Arkema Corporation), and used in the addition amounts (parts per 100 parts by mass of the resin) described in Table 1 to manufacture a charging roller.

[0185] [Examples 2-3, Comparative Examples 2-3]

[0186] The same as Example 1, however, the addition amount (parts per 100 parts by mass of the resin) of the aluminum nitride particles was changed to the addition amounts described in Table 1 to manufacture a charging roller.

[0187] [Examples 4-6]

[0188] The same as Example 1, however, the non-conductive particles were changed to boron nitride particles (PT620, Momentive Performance Materials Inc.), and used in the addition amounts (parts per 100 parts by mass of the resin) described in Table 1 to manufacture a charging roller.

[0189] [Examples 7-9]

[0190] The same as Example 1, however, the non-conductive particles were changed to magnesium oxide particles (RF-10C-AC, Ube Materials Industry Co., Ltd.), and used in the addition amounts (parts per 100 parts by mass of the resin) described in Table 1 to manufacture a charging roller.

[0191] [Example 10]

[0192] Similar to Example 1, however, the non-conductive particles were changed to alumina particles (DAW-03, Denka Co., Ltd.), and they were used in the amounts shown in Table 1 (parts per 100 parts by mass of the resin), and a charging roller was manufactured.

[0193] [Examples 11 to 13]

[0194] Similar to Example 1, however, the non-conductive particles were changed to aluminum nitride particles with different particle sizes, and they were used in the amounts shown in Table 1 (parts per 100 parts by mass of the resin), and a charging roller was manufactured.

[0195] The aluminum nitride particles used in Examples 11 to 13 are as follows. The average primary particle size of each aluminum nitride particle is shown in Table 1.

[0196] · Example 11: AIN020AW, Thrutek

[0197] · Example 12: AIN0300AW, Thrutek

[0198] · Example 13: AIN0200AW, Thrutek

[0199] <Performance Evaluation of Charging Component>

[0200] [Thermal Conductivity]

[0201] From the axial center of the charging roller, a sample was cut out from the elastic layer to the surface layer with a size of 5 mm in the axial direction × 2 mm in the circumferential direction. At room temperature (25°C ± 3°C), the sample was placed on the probe of a thermal diffusivity measurement device ai-Phase Mobile (ai-Phase Co., Ltd.), a counterweight of 100 gf was placed, and it was measured three times under the conditions of manual mode, voltage 1.41 V, frequency 1 Hz to 10 Hz (10 divisions), and measurement time 2 seconds, and the average value was calculated.

[0202] [Concentration Non-uniformity]

[0203] The manufactured charging roller was installed in an image forming apparatus Apeos C2360 (Fuji Film Business Innovation Co., Ltd.).

[0204] In an environment of temperature 28°C and relative humidity 80%, 400,000 black halftone images with a concentration of 50% were output on the entire single side of A3-size plain paper. Then, in an environment of temperature 10°C and relative humidity 15%, 1 black halftone image with a concentration of 30% was output on the entire single side of A3-size plain paper.

[0205] At one central location and four end locations of a black medium-tone image with a concentration of 30%, the image concentration was measured using a reflection densitometer X-Rite 404A (X-Rite Inc.). The difference between the maximum and minimum values of the image concentration was calculated and classified as follows.

[0206] 1: The difference in image concentration is less than 0.3.

[0207] 2: The difference in image concentration is 0.3 or more and 1.0 or less. This is the allowable range.

[0208] 3: The difference in image concentration exceeds 1.0. This is not allowable.

[0209] [Crack]

[0210] The surface of the charging roller after the evaluation of concentration unevenness was observed with an optical microscope. The presence or absence of cracks and the crack width were classified as follows.

[0211] 0: No cracks.

[0212] 1: There are cracks, the crack width is less than 10 μm, and the crack length is less than 0.5 mm.

[0213] 2: There are cracks, the crack width is less than 10 μm, and the crack length is 0.5 mm or more.

[0214] 3: There are cracks with a crack width of 10 μm or more.

[0215] [Table 1]

[0216]

[0217] (Supplementary Note) (((1)))

[0219] A charging member, wherein,

[0220] It has a support member, an elastic layer provided on the support member, and a surface layer provided on the elastic layer,

[0221] The surface layer contains a resin, conductive particles, and non-conductive inorganic particles,

[0222] The surface layer contains 5 to 40 parts by mass of the non-conductive inorganic particles with respect to 100 parts by mass of the resin. (((2)))

[0224] According to the charging member described in (((1))), wherein,

[0225] The thermal conductivity of the non-conductive inorganic particles is 40 W / (m·K) or more. (((3)))

[0227] The charging member according to ((1)) or ((2)), wherein

[0228] The non-conductive inorganic particles include at least one selected from the group consisting of nitride particles, oxide particles, carbide particles, and boride particles. ((4))

[0230] The charging member according to any one of ((1)) to ((3)), wherein

[0231] The non-conductive inorganic particles include at least one selected from the group consisting of aluminum nitride particles, boron nitride particles, and magnesium oxide particles. ((5))

[0233] The charging member according to any one of ((1)) to ((4)), wherein

[0234] The average primary particle diameter of the non-conductive inorganic particles is 5 μm or more and 20 μm or less. ((6))

[0236] A charging device having the charging member according to any one of ((1)) to ((5)). ((7))

[0238] A process cartridge, wherein

[0239] Comprising:

[0240] A photoreceptor; and

[0241] A charging device having the charging member according to any one of ((1)) to ((5)) and charging the photoreceptor,

[0242] The process cartridge is detachable from the image forming apparatus. ((8))

[0244] An image forming apparatus comprising:

[0245] A photoreceptor;

[0246] A charging device having the charging member according to any one of ((1)) to ((5)) and charging the photoreceptor;

[0247] An electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged photoreceptor;

[0248] A developing device that uses a developer containing toner to develop an electrostatic latent image formed on the surface of the photoreceptor to form a toner image; and

[0249] A transfer device that transfers the toner image onto the surface of a recording medium.

[0250] According to ((1)), ((3)), or ((4)), there is provided a charging member that is less likely to cause density unevenness in an image and is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass relative to 100 parts by mass of the resin.

[0251] According to ((2)), there is provided a charging member that is less likely to cause density unevenness in an image and is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles with a thermal conductivity lower than 40 W / (m·K).

[0252] According to ((5)), there is provided a charging member that is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles with an average particle diameter exceeding 20 μm.

[0253] According to ((6)), there is provided a charging device including a charging member that is less likely to cause density unevenness in an image and is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass relative to 100 parts by mass of the resin.

[0254] According to ((7)), there is provided a process cartridge including a charging member that is less likely to cause density unevenness in an image and is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass relative to 100 parts by mass of the resin.

[0255] According to ((8)), there is provided an image forming apparatus including a charging member that is less likely to cause density unevenness in an image and is less likely to generate cracks on the surface compared to a charging member having a surface layer containing non-conductive inorganic particles in an amount less than 5 parts by mass or more than 40 parts by mass relative to 100 parts by mass of the resin.

Claims

1. A charging component, characterized in that: have: Support components; an elastic layer disposed on the supporting member; and a surface layer, the surface layer being disposed on the elastic layer, The surface layer contains resin, conductive particles, and non-conductive inorganic particles. The surface layer contains 5 parts by mass or more and 40 parts by mass or less of the non-conductive inorganic particles relative to 100 parts by mass of the resin.

2. The charging member according to claim 1, wherein The thermal conductivity of the non-conductive inorganic particles is 40 W / (m·K) or more.

3. The charging member according to claim 1 or 2, wherein The non-conductive inorganic particles include at least one selected from the group consisting of nitride particles, oxide particles, carbide particles, and boride particles.

4. The charging member according to any one of claims 1 to 3, wherein The non-conductive inorganic particles include at least one selected from the group consisting of aluminum nitride particles, boron nitride particles, and magnesium oxide particles.

5. The charging member according to any one of claims 1 to 4, wherein The non-conductive inorganic particles have an average primary particle size of 5 μm or more and 20 μm or less. 6 . A charging device comprising the charging member according to claim 1 .

7. A processing box, characterized in that: have: a photoreceptor; and A charging device, comprising a charging member according to any one of claims 1 to 5, for charging the photoreceptor, The process cartridge is attachable to and detachable from the image forming apparatus.

8. An image forming device, characterized in that: have: Photoreceptor; A charging device, comprising a charging member according to any one of claims 1 to 5, for charging the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoreceptor; a developing device that develops the electrostatic latent image formed on the surface of the photoreceptor using a developer containing a toner to form a toner image; as well as A transfer device transfers the toner image onto a surface of a recording medium.

Images