Charging member, method for manufacturing charging member, charging device, process cartridge, and image forming apparatus

Abstract

To provide a charging member in which a surface is not easily contaminated and cracks are not easily generated in an external layer even after a long-term use.SOLUTION: A charging member has a support member, an elastic layer, an external layer, and a protective layer being an outermost layer. The protective layer contains silica and has a silicon element concentration of 10 atomic% or more. An outer peripheral surface has a contact angle with water of 35 degrees or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses an electrostatic charging member having a surface layer formed thereon that contains a silicone resin containing silicon atoms to which a compound having a hydrophilic group is bonded, and the contact angle of the surface of the electrostatic charging member with water is 25 degrees or less.

[0003] Patent Document 2 discloses an electrostatic charging member having a conductive support and a conductive body, the conductive body having an elastic layer, a resin layer, and a coating layer forming the outermost surface, the coating layer containing a polysiloxane compound having a Si-O-Zr bond in its molecular structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-202733 A [Patent Document 2] JP 2022-003370 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide an electrostatically charged member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to an electrostatically charged member whose protective layer has a silicon element concentration of less than 10 atomic % and whose outer peripheral surface has a water contact angle of more than 35 degrees. [Means for solving the problem]

[0006] Specific means for solving the above problems include the following aspects. <1> A support member; an elastic layer provided on the support member; an outer layer disposed on the elastic layer; a protective layer that is an outermost layer provided on the outer layer, The protective layer contains silica and has a silicon element concentration of 10 atomic % or more, The water contact angle of the outer surface is 35 degrees or less. Charged member. <2> The water contact angle of the outer peripheral surface is 25 degrees or less. <1> The charging member according to claim 1. <3> The silicon element concentration of the protective layer is 20 atomic % or more and 33 atomic % or less. <1> or <2> The charging member according to claim 1. <4> The silica content of the protective layer is 25% by mass or more and 100% by mass or less. <1> ~ <3> 13. The charging member according to claim 12, <5> The thickness of the protective layer is 1 μm or more and 10 μm or less. <1> ~ <4> 13. The charging member according to claim 12, <6> <1> ~ <5> A method for producing the electrostatic member according to any one of the above items, providing a member having, in order, a support member, an elastic layer, an outer layer, and a layer containing silica; and contacting the silica-containing layer with alkaline electrolyzed water to provide a hydroxyl group on the surface of the silica-containing layer to form a protective layer. A method for manufacturing an electrostatic charging member. <7> <1> ~ <5> 2. A charging device comprising the charging member according to claim 1. <8> A photoconductor; <1> ~ <5> a charging device having the charging member according to any one of claims 1 to 5, wherein the charging member contacts the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; A process cartridge that is detachably attached to an image forming apparatus. <9> A photoconductor; <1> ~ <5> a charging device having the charging member according to any one of claims 1 to 5, wherein the charging member contacts the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; a developing device for developing the electrostatic latent image formed on the surface of the photoconductor with a developer containing a toner to form a toner image; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising: Effect of the Invention

[0007] <1> , <4> or <5> According to the present invention, an electrostatic member is provided whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to an electrostatic member whose protective layer has a silicon element concentration of less than 10 atomic % and whose outer peripheral surface has a water contact angle of more than 35 degrees. <2> According to the present invention, an electrostatic charging member is provided whose surface is less susceptible to contamination even when used for a long period of time, compared to an electrostatic charging member whose outer peripheral surface has a water contact angle of more than 25 degrees. <3> According to the present invention, an electrostatic charging member is provided in which cracks are less likely to occur in the outer layer even when used for a long period of time, compared to an electrostatic charging member in which the silicon concentration in the protective layer is less than 20 atomic %. <6> According to the present invention, there is provided a method for producing an electrostatic member in which the surface is less susceptible to contamination and the outer layer is less susceptible to cracking even after long-term use, compared to a production method in which the layer containing silica is not brought into contact with alkaline electrolytic water. <7> According to this, a charging device is provided that includes a charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to when the silicon concentration of the protective layer of the charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. <8> According to this, a process cartridge is provided that is equipped with an electrostatic charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to when the silicon concentration of the protective layer of the electrostatic charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. <9> According to this, an image forming apparatus is provided that is equipped with a charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to when the silicon concentration of the protective layer of the charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic perspective view illustrating an example of a charging member according to the present embodiment. [Diagram 2] 2 is a schematic cross-sectional view showing an example of a charging member according to the present embodiment, taken along the line AA in FIG. [Diagram 3] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiments, and are not intended to limit the scope of the embodiments.

[0010] In the present disclosure, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0011] In the present disclosure, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.

[0012] When an embodiment of the present disclosure is described 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 the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0013] In the present disclosure, each component may contain multiple types of corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified. In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0014] In this disclosure, the "axial direction" of the charging member means the direction in which the rotation axis of the charging member extends, and the "circumferential direction" of the charging member means the rotation direction of the charging member.

[0015] <Charging material> The charging member according to this embodiment has a support member, an elastic layer provided on the support member, an outer layer provided on the elastic layer, and a protective layer provided on the outer layer.

[0016] Fig. 1 is a schematic perspective view showing an example of a charging member according to the present embodiment, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, showing the charging member shown in Fig. 1 cut in the radial direction. 1 is a roll-shaped charging member. The charging member 30 has a structure in which an elastic layer 34, an outer layer 36, and a protective layer 38 are laminated in this order on a support member 32. The charging member 30 may have an adhesive layer (not shown) between the support member 32 and the elastic layer 34.

[0017] The shape of the charging member according to the present embodiment is not limited to a roll shape, but may be a belt shape, a tube shape, a blade shape, or the like.

[0018] In the charging member according to this embodiment, the protective layer contains silica (silicon dioxide, SiO2) and has a silicon element concentration of 10 atomic % or more, and the water contact angle of the outer circumferential surface is 35 degrees or less.

[0019] The charging member according to this embodiment is unlikely to become contaminated on its surface and unlikely to develop cracks in its outer layer even when used for a long period of time. The reason for this is presumed to be as follows.

[0020] When image formation is performed for a long period of time, dirt gradually accumulates on the surface of the charging member. This dirt is mainly derived from the toner and contains components of the toner base particles and components of the toner external additives. Surface dirt on the charging member is likely to occur in a charging member that contacts the photoreceptor surface, but can also occur in a charging member that does not contact the photoreceptor surface because the toner is electrostatically attracted. The dirt on the surface of the charging member causes an increase in electrical resistance in that area, which reduces the charging uniformity of the charging member. As a result, image defects such as uneven image density and unintended streaky images may occur. Furthermore, when the charging member comes into contact with other members (e.g., a photoconductor or a member for cleaning the charging member), stress is concentrated on the dirty part of the surface of the charging member, which may cause cracks to form in the outer layer of the charging member starting from the dirty part. The charging member according to the present embodiment has a protective layer containing silica, and the silicon element concentration in the protective layer is 10 atomic % or more, thereby suppressing the accumulation of toner-based stains. In addition, silicon has corrosion resistance and deterioration resistance properties. By having the silicon element concentration in the protective layer be 10 atomic % or more, deterioration of the resin in the outer layer due to discharge is suppressed, and the occurrence of cracks in the outer layer is suppressed. Furthermore, in the electrostatically charged member according to this embodiment, the contact angle of water on the outer peripheral surface is 35 degrees or less, i.e., hydrophilic groups (e.g., hydroxyl groups) are arranged so as to cover the outer peripheral surface, which is presumably why adhesion of dirt can be suppressed and charging uniformity can be maintained.

[0021] In the charging member according to this embodiment, from the viewpoint of suppressing the accumulation of toner-based contaminants and from the viewpoint of suppressing deterioration of the resin of the outer layer due to discharge, the silicon element concentration of the protective layer is 10 atomic % or more, preferably 15 atomic % or more, and more preferably 20 atomic % or more. In the charging member according to this embodiment, the silicon element concentration in the protective layer may be 33 atomic % or less, 30 atomic % or less, or 25 atomic % or less.

[0022] In the charging member according to the present embodiment, from the viewpoint of preventing adhesion of dirt, the contact angle of water on the outer peripheral surface is 35 degrees or less, preferably 30 degrees or less, and more preferably 25 degrees or less. From the viewpoint of preventing adhesion of dirt, the lower the contact angle of water on the outer peripheral surface, the better. The charging member according to this embodiment may have a water contact angle of 0 degrees or more on the outer peripheral surface, 10 degrees or more, or 15 degrees or more.

[0023] The silicon element concentration in the protective layer of the charging member is determined by analyzing the elemental composition of the protective layer by SEM-EDX (Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy). The specific analysis method is as follows. The protective layer is peeled off from the support member at the axial center of the charging member, and this is used as a sample. If it is difficult to peel off only the protective layer, the outer layer and the protective layer are peeled off, and this is used as a sample. The thickness of the protective layer is measured, and the detection depth of the SEM-EDX is adjusted so that the protective layer is the subject of analysis. EDX equipment (HORIBA EMAX ENERGY, detector: X-Max 80 mm 2The sample is photographed at a magnification of 150x using an SEM (Hitachi S-4800) equipped with a 1.5 mm hologram microscope. The accelerating voltage of the SEM is 20 kV. Three fields of view are photographed in a rectangle of 0.8 mm in the axial direction and 1.4 mm in the circumferential direction. All elements detected are quantified, and the percentage of silicon element in the protective layer (atomic %) is calculated.

[0024] The contact angle of water on the outer peripheral surface of the charging member is measured as follows. The electrostatically charged member is placed in an environment with a temperature of 22°C and a relative humidity of 55% for 24 hours or more to adjust the temperature and humidity. In an environment with a temperature of 22 degrees and a relative humidity of 55%, the axial direction of the charged member is fixed horizontally, a 1.0 μL drop of ion-exchanged water is dropped onto the apex at the center of the axial direction of the charged member, and the contact angle 10 seconds after the drop is measured by the sessile drop method. The drop of water and the measurement of the contact angle are performed using an automatic contact angle measuring device (Kyowa Interface Science CA-X). Measurements are made at four positions at 90° intervals around the circumference of the charged member, and the four measured values ​​are arithmetically averaged.

[0025] Each layer of the charging member will now be described in detail.

[0026] [Support member] 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 solid member, for example, a rod-shaped, cylindrical, or endless belt-shaped member.

[0027] Examples of support members include metal members such as iron (free-cutting steel, etc.), copper, copper alloys, brass, stainless steel, aluminum, nickel, etc.; iron members plated with chromium, nickel, etc.; resin or ceramic members whose outer surfaces have been plated; and resin or ceramic members containing a conductive agent.

[0028] [Elastic layer] The elastic layer is conductive and has a volume resistivity of 1×10 at 20°C. 3 Ωcm or more 1×10 14 It is preferable that the resistivity is Ωcm or less.

[0029] The volume resistivity of the elastic layer is a value measured by the following method. A sheet-shaped measurement sample is taken from the elastic layer, and a voltage adjusted to an electric field (applied voltage / composition sheet thickness) of 1000 V / cm is applied to the measurement sample for 30 seconds using a measurement tool (R12702A / B resistivity chamber: manufactured by Advantest Corporation) and a high resistance measuring instrument (R8340A digital high resistance / micro ammeter: manufactured by Advantest Corporation) in accordance with JIS K 6911 (1995). The current value is read and calculated using the following formula. Volume resistivity (Ωcm) = (19.63 x applied voltage (V)) / (current value (A) x measured sample thickness (cm))

[0030] The elastic layer may be a foamed elastic layer or a non-foamed elastic layer. The elastic layer may be disposed directly on the outer peripheral surface of the support member, or may be disposed on the outer peripheral surface of the support member via an adhesive layer.

[0031] One embodiment of the elastic layer includes an elastic material, a conductive agent, and other additives.

[0032] Examples of elastic materials 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, butadiene rubber, chloroprene rubber, chlorinated polyisoprene, hydrogenated polybutadiene, butyl rubber, silicone rubber, fluororubber, natural rubber, and elastic materials made 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 made by mixing two or more of these are preferable.

[0033] Examples of the conductive agent include electronic conductive agents and ionic conductive agents. Examples of the electronic conductive agent include 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 substances in which the surface of an insulating material is treated to be conductive. Examples of the ionic conductive agent include perchlorates or chlorates such as tetraethylammonium, lauryltrimethylammonium, and benzyltrialkylammonium; perchlorates or chlorates of alkali metals or alkaline earth metals such as lithium and magnesium; and the like. The conductive agent may be used alone or in combination of two or more.

[0034] The total content of the conductive agent in the elastic layer is preferably set based on the volume resistivity of the elastic layer. When an electronic conductive agent is used as the conductive agent, the total amount of the electronic conductive agent may be, for example, 1 part by mass or more and 20 parts by mass or less, or 3 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the elastic material. When an ionic conductive agent is used as the conductive agent, the total amount of the ionic conductive agent may be, for example, 0.1 parts by mass to 10 parts by mass, or 0.5 parts by mass to 5 parts by mass, relative to 100 parts by mass of the elastic material.

[0035] The average primary particle size of the conductive agent is preferably 1 nm or more and 500 nm or less, and more preferably 5 nm or more and 200 nm or less. 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 particles, and calculating the arithmetic average.

[0036] The conductive agent is preferably carbon black, and the average primary particle size of carbon black is preferably 1 nm or more and 500 nm or less, and more preferably 5 nm or more and 200 nm or less. The content of carbon black is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 3 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the elastic material.

[0037] Examples of other additives include vulcanizing agents, vulcanization accelerators, vulcanization acceleration assistants, fillers, softeners, plasticizers, hardeners, antioxidants, surfactants, and coupling agents.

[0038] Examples of the filler include calcium carbonate, silica, clay minerals, etc. The filler may be used alone or in combination of two or more kinds.

[0039] The filler is preferably calcium carbonate. The content of calcium carbonate is preferably 1 part by mass or more and 50 parts by mass or less, and 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.

[0040] The thickness of the elastic layer is preferably 1 mm or more and 10 mm or less, and more preferably 2 mm or more and 5 mm or less. The thickness of the elastic layer is measured by imaging a cross section with an electron microscope, measuring four locations at 90° intervals in the circumferential direction at the axial center of the charging member, and calculating the arithmetic average value to determine the thickness of the elastic layer.

[0041] Examples of the method for forming an elastic layer on a support member include a method in which an elastic layer-forming composition containing an elastic material, a conductive agent, and other additives is extruded from an extruder together with a cylindrical support member to form a layer of the elastic layer-forming composition on the outer peripheral surface of the support member, and then the layer of the elastic layer-forming composition is heated to undergo a crosslinking reaction (including vulcanization) to form an elastic layer; a method in which an elastic layer-forming composition containing an elastic material, a conductive agent, and other additives is extruded from an extruder onto the outer peripheral surface of an endless belt-like support member to form a layer of the elastic layer-forming composition on the outer peripheral surface of the support member, and then the layer of the elastic layer-forming composition is heated to undergo a crosslinking reaction (including vulcanization) to form an elastic layer; and the like. The support member may have an adhesive layer on its outer peripheral surface.

[0042] [Adhesive layer] An adhesive layer may be provided between the support member and the elastic layer to bond them together. Specific examples of the adhesive layer 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, phenol resin, silicone resin, etc. The adhesive layer may contain a conductive agent (for example, the above-mentioned electronic conductive agent or ionic conductive agent).

[0043] From the viewpoint of adhesion between the elastic layer and the support member, the thickness of the adhesive layer is preferably from 1 μm to 50 μm, more preferably from 2 μm to 40 μm, and even more preferably from 5 μm to 20 μm. The thickness of the adhesive layer is measured by photographing the cross section with an electron microscope, measuring four points at 90° intervals in the circumferential direction at the axial center of the charging member, and taking the arithmetic average value as the thickness of the adhesive layer.

[0044] [Outer layer] The outer layer is electrically conductive and has a volume resistivity of 1×10 at 20°C. 3 Ωcm or more 1×10 14 The volume resistivity of the outer layer is preferably Ωcm or less. The volume resistivity of the outer layer is a value measured by the same method as that of the elastic layer.

[0045] One embodiment of the outer layer includes a resin, a conductive agent, and other additives.

[0046] Examples of the resin contained in the outer layer include copolymer nylon, polyamide, polyimide, polyamideimide, polyester, polyethylene terephthalate, polyarylate, polycarbonate, polyethylene, polyurethane, phenol resin, silicone resin, acrylic resin, fluorine-modified acrylic resin, silicone-modified acrylic resin, melamine resin, epoxy resin, fluororesin, polyvinylidene fluoride resin, tetrafluoroethylene resin, polyvinyl butyral, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluororubber, polyvinyl resin, polyvinyl alcohol, polyvinyl acetal, polyvinylidene chloride, polyvinyl chloride, ethylene-vinyl acetate copolymer, cellulose, polythiophene resin, 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. One type of resin may be used alone, or two or more types may be used in combination.

[0047] From the viewpoint of suppressing contamination of the outer layer, polyamide, polyvinylidene fluoride resin, and tetrafluoroethylene resin are preferable, and polyamide is more preferable. As the polyamide, from the viewpoint of suppressing contamination of the outer layer, alcohol-soluble polyamide is preferable, alkoxymethylated polyamide (alkoxymethylated nylon) is more preferable, and methoxymethylated polyamide (methoxymethylated nylon) is further preferable.

[0048] The conductive material in the outer layer has a volume resistivity of 1×10 9 Conductive particles having a resistivity of Ωcm or less are preferable. Examples of conductive particles include metal oxides such as tin oxide, titanium oxide, and zinc oxide; carbon black; and the like.

[0049] From the viewpoint of excellent dispersibility in resin, the conductive particles contained in the outer layer preferably have a primary particle size of 10 nm or more and 50 nm or less.

[0050] The content of the conductive particles in the outer layer is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the resin.

[0051] The outer layer may contain roughness-forming particles for the purpose of forming fine roughness on its surface. The roughness-forming particles may be inorganic particles or organic particles. Examples of the roughness-forming particles include inorganic particles such as silica particles, alumina particles, and zircon particles; and resin particles such as polyamide particles, fluororesin particles, and silicone resin particles. From the viewpoint of reducing the contamination of the charging member, resin particles are preferred, and polyamide particles are more preferred. The roughness-forming particles may be used alone or in combination of two or more kinds.

[0052] The volume average particle diameter of the unevenness-forming particles is preferably 5 μm or more and 20 μm or less, and more preferably 5 μm or more and 10 μm or less. The volume average particle diameter of the unevenness-forming particles is determined by observing the cross section of the outer layer with an electron microscope, measuring the major axis of 100 particles, and creating a volume-based particle size distribution assuming that the particles are true spheres. The volume average particle diameter is the cumulative 50% particle diameter from the smallest diameter side.

[0053] When the outer layer contains roughness-forming particles, the content of the roughness-forming particles is preferably 5 parts by mass or more and 30 parts by mass or less, and more preferably 8 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the resin.

[0054] The outer layer preferably contains 5 to 30 parts by mass of unevenness-forming particles having a volume average particle size of 5 μm or more and 20 μm or less per 100 parts by mass of resin, and more preferably contains 8 to 20 parts by mass of unevenness-forming particles having a volume average particle size of 5 μm or more and 10 μm or less per 100 parts by mass of resin.

[0055] Examples of other additives include vulcanizing agents, vulcanization accelerators, vulcanization acceleration assistants, fillers, softeners, plasticizers, hardeners, antioxidants, surfactants, and coupling agents.

[0056] The thickness of the outer layer is preferably from 1 μm to 25 μm, more preferably from 2 μm to 20 μm, and even more preferably from 3 μm to 15 μm. The thickness of the outer layer is measured by photographing a cross section with an electron microscope, measuring four locations at 90° intervals in the circumferential direction at the axial center of the charging member, and calculating the arithmetic average value to determine the thickness of the outer layer.

[0057] Examples of the method for forming the outer layer on the elastic layer include a method in which an outer layer forming composition containing a mixture of a resin, a conductive agent, unevenness-forming particles, and other additives is applied to the outer peripheral surface of the elastic layer to form a layer of the outer layer forming composition, and then the layer of the outer layer forming composition is dried. Examples of the method for applying the outer layer forming composition to the outer peripheral surface of the elastic layer include dip coating, roll coating, blade coating, wire bar coating, spray coating, bead coating, air knife coating, curtain coating, and the like.

[0058] [Protective layer] The protective layer is a layer containing silica (silicon dioxide, SiO2). The protective layer may contain a compound other than silica, such as resins such as polyester resin and styrene-acrylic resin, waxes, inorganic particles such as titania (TiO2) and alumina (Al2O3), metal salts of higher fatty acids, and modified components of these compounds.

[0059] The silica content of the protective layer is preferably 25% by mass or more, more preferably 35% by mass or more, and even more preferably 45% by mass or more, from the viewpoint of preventing the accumulation of toner-based dirt and preventing the resin of the outer layer from deteriorating due to discharge and thus preventing cracks from occurring in the outer layer. The silica content of the protective layer may be 100% by mass, or may be 85% by mass or less, or may be 70% by mass or less.

[0060] From the viewpoint of protecting the outer layer, the thickness of the protective layer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 4 μm or more. From the viewpoint of ensuring the charging performance of the charging member, the thickness of the protective layer is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less.

[0061] The thickness of the protective layer is measured by imaging a cross section with an electron microscope, measuring four locations at 90° intervals in the circumferential direction at the axial center of the charging member, and calculating the arithmetic average value to determine the thickness of the protective layer.

[0062] The method for forming the protective layer is not particularly limited, and may be, for example, a method in which a silica-containing layer forming step and a surface treatment step, which will be described later, are carried out in that order.

[0063] <Method of manufacturing electrostatic charging member> As a method for producing the charging member according to the present embodiment, for example, the following embodiment can be mentioned.

[0064] An example of an embodiment of a method for producing an electrostatic member includes preparing a member having a support member, an elastic layer, an outer layer, and a layer containing silica in this order, and contacting the layer containing silica with alkaline electrolyzed water to impart hydroxyl groups to the surface of the layer containing silica to form a protective layer (surface treatment step). Hereinafter, the "layer containing silica" may also be referred to as a "silica-containing layer."

[0065] As an example of an embodiment of preparing a member having a support member, an elastic layer, an outer layer, and a silica-containing layer in this order, a charging member is removed from an image forming apparatus after use. When a member having a support member, an elastic layer, and an outer layer in this order is continuously used as a charging member, toner migrates from the photoreceptor onto the outer layer of the charging member, and a silica-containing layer containing a component derived from silica particles, which is an external additive to the toner, is formed on the outer layer. The charging member removed from the image forming apparatus after use can be regenerated by subjecting the charging member to a surface treatment process using alkaline electrolytic water. The charging member in this case is a so-called regenerated charging member.

[0066] One example of an embodiment of preparing a member having a support member, an elastic layer, an outer layer, and a silica-containing layer in this order is forming a silica-containing layer on the outer layer of a member having a support member, an elastic layer, and an outer layer in this order (silica-containing layer formation process).

[0067] [Silica-containing layer forming process] A member having a support member, an elastic layer, and an outer layer in this order is obtained by forming the elastic layer on the support member and forming the outer layer on the elastic layer. Specific forms of the method of forming the elastic layer on the support member and the method of forming the outer layer on the elastic layer are as described above. The support member and the elastic layer may be bonded with an adhesive layer.

[0068] The silica-containing layer forming step is a step of forming a silica-containing layer (the base film of the protective layer) on the outer layer of the above-mentioned component, and the silica-containing layer is formed so that the silicon element concentration of the silica-containing layer is 10 atomic % or more.

[0069] Examples of methods for forming the silica-containing layer include known film formation methods using silica (silicon dioxide, SiO2) as a material, such as plasma CVD (Chemical Vapor Deposition), vacuum deposition, sputtering, and ion plating.

[0070] Another method for forming a silica-containing layer is to mount a member having a support member, an elastic layer, and an outer layer in this order on a mounting portion of a charging member in an electrophotographic image forming apparatus, operate the image forming apparatus, and form an image using a toner to which silica particles are added. That is, the above-mentioned member is used as a charging member to form an image. According to this method, the toner is transferred from the photoreceptor onto the outer layer of the member, and a silica-containing layer containing a component derived from the silica particles, which is an external additive to the toner, is formed on the outer layer. The image forming apparatus used in the above method may be of a type in which a charging member does not contact the photoconductor (the charging member electrostatically attracts the toner), but a type in which a charging member contacts the photoconductor is more efficient. The above method makes it possible to adjust the silicon element concentration of the silica-containing layer depending on the amount of image formation. The greater the amount of image formation, the higher the silicon element concentration of the silica-containing layer tends to be.

[0071] The toner used in the above method may have silica particles added thereto, and the toner base particles and other external additives are not limited. The toner base particles contain, for example, a binder resin such as polyester resin or styrene acrylic resin, and a release agent (various waxes). The toner base particles may or may not contain a colorant. Examples of other external additives include inorganic particles such as titania (TiO2) and alumina (Al2O3); cleaning active agents (for example, higher fatty acid metal salts such as zinc stearate); and the like.

[0072] [Surface treatment process] The surface treatment process is a process in which the silica-containing layer is brought into contact with alkaline electrolytic water to impart hydroxyl groups to the surface of the silica-containing layer to form a protective layer, and the surface treatment is performed so that the contact angle of water on the surface of the protective layer (i.e., the outer peripheral surface of the charging member) is 35 degrees or less.

[0073] Alkaline electrolyzed water is water produced by electrolyzing water. When alkaline electrolyzed water is brought into contact with a silica-containing layer, hydroxyl groups (-OH) are added to the surface of the silica-containing layer, decreasing the contact angle of the surface with water.

[0074] The method for bringing the silica-containing layer into contact with the alkaline electrolyzed water includes dip coating, spray coating, etc. After bringing the silica-containing layer into contact with the alkaline electrolyzed water, it is preferable to dry it at room temperature.

[0075] The contact angle of water on the surface of the protective layer (that is, the outer circumferential surface of the charging member) can be adjusted by adjusting the pH of the alkaline electrolyzed water and the time that the silica-containing layer is in contact with the alkaline electrolyzed water. The pH of the alkaline electrolyzed water is preferably 10 or more, and more preferably 11 or more, in terms of the efficiency of providing hydroxyl groups. The pH of the alkaline electrolyzed water is preferably 12 or less in order to prevent corrosion of the support member and denaturation of the outer layer and the elastic layer. The time during which the silica-containing layer is in contact with the alkaline electrolyzed water is preferably adjusted according to the pH of the alkaline electrolyzed water. When the alkaline electrolyzed water has a pH of 12, the contact time is preferably 30 seconds or more and 30 minutes or less.

[0076] <Charging device, image forming apparatus, process cartridge> The charging device according to the present embodiment has the charging member according to the present embodiment. The charging device according to the present embodiment may be a charging device in which the charging member contacts the surface of the photoconductor, or may be a charging device in which the charging member does not contact the surface of the photoconductor. In a charging device in which the charging member contacts the surface of the photoconductor, the effect of the present embodiment (the surface of the charging member is less likely to be contaminated and the outer layer is less likely to crack) is remarkable.

[0077] The image forming apparatus according to the present embodiment includes a photoconductor, a charging device for charging the surface of the photoconductor, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged photoconductor, a developing device for developing the electrostatic latent image formed on the surface of the photoconductor 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. As the charging device, a charging device having a charging member according to the present embodiment is applied. The charging device may be a charging device of a type in which the charging member contacts the surface of the photoconductor, or a charging device of a type in which the charging member does not contact the surface of the photoconductor. In a charging device of a type in which the charging member contacts the surface of the photoconductor, the effect of the present embodiment (the surface of the charging member is less likely to be contaminated and the outer layer is less likely to crack) is remarkable.

[0078] In the image forming apparatus according to the present embodiment, for example, a portion including the photoconductor and the charging device may have a cartridge structure (i.e., the process cartridge according to the present embodiment) that is detachably attached to the image forming apparatus. The process cartridge may include, in addition to the photoconductor and the charging device, at least one selected from the group consisting of an electrostatic latent image forming device, a developing device, and a transfer device. The charging device may be a charging device of a type in which the charging member contacts the surface of the photoconductor, or a charging device of a type in which the charging member does not contact the surface of the photoconductor. In a charging device of a type in which the charging member contacts the surface of the photoconductor, the effect of the present embodiment (the surface of the charging member is less likely to be contaminated and the outer layer is less likely to crack) is remarkable.

[0079] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as an apparatus equipped with a fixing device that fixes a toner image transferred onto the surface of a recording medium; an apparatus using a direct transfer method that directly transfers a toner image formed on the surface of a photoconductor onto a recording medium; an apparatus using an intermediate transfer method that performs primary transfer of a toner image formed on the surface of a photoconductor onto the surface of an intermediate transfer body, and then performs secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of a recording medium; an apparatus equipped with a cleaning device that cleans the surface of a photoconductor before charging after the transfer of a toner image; an apparatus equipped with a static elimination device that irradiates the surface of a photoconductor with static elimination light to eliminate static electricity before charging after the transfer of a toner image; and an apparatus equipped with a photoconductor heating member for increasing the temperature of the photoconductor and reducing the relative temperature.

[0080] In the case of an intermediate transfer type device, the transfer device is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer device which primarily transfers the toner image formed on the surface of a photosensitive body onto the surface of the intermediate transfer body, and a secondary transfer device which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of a recording medium.

[0081] The image forming apparatus according to the present embodiment may be either a dry development type image forming apparatus or a wet development type image forming apparatus (a development type using a liquid developer).

[0082] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Principal parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0083] FIG. 3 is a schematic diagram showing an example of an image forming apparatus according to the present embodiment. As shown in FIG. 3, 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 body 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where it can expose the photoconductor 7 from the opening of the process cartridge 300, the transfer device 40 is disposed at a position facing the photoconductor 7 via the intermediate transfer body 50, and the intermediate transfer body 50 is disposed with a part of it in contact with the photoconductor 7. Although not shown, the image forming apparatus 100 also includes 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 (a primary transfer device), and the secondary transfer device (not shown) correspond to an example of a transfer device.

[0084] 3 supports the photoconductor 7, charging device 8, developing device 11, and cleaning device 13 integrally within a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, which is disposed so as to come into contact with the surface of the photoconductor 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

[0085] FIG. 3 shows an example of an image forming apparatus including a fibrous member 132 (roll-shaped) that supplies lubricant 14 to the surface of the photoreceptor 7, and a fibrous member 133 (flat brush-shaped) that assists in cleaning, which may be arranged as needed.

[0086] Hereinafter, each configuration of the image forming apparatus according to this embodiment will be described.

[0087] -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 type photosensitive layer or a laminate type photosensitive layer composed of a charge generating layer and a charge transport layer.

[0088] -Charging device- The charging device 8 has a charging member according to this embodiment. The charging device 8 may be a charging device of a type in which the charging member contacts the photoreceptor surface, or a charging device of a type in which the charging member does not contact the photoreceptor surface. The charging device 8 may be any of the following: a charging device of a type in which only a DC voltage is applied to the charging member (DC charging type); a charging device of a type in which only an AC voltage is applied to the charging member (AC charging type); or a charging device of a type in which a voltage in which an AC voltage is superimposed on a DC voltage is applied to the charging member (AC / DC charging type).

[0089] -Exposure equipment- The exposure device 9 may be, for example, an optical device that exposes the surface of the photoconductor 7 with light such as semiconductor laser light, LED light, or liquid crystal shutter light in a predetermined image. The wavelength of the light source is within the spectral sensitivity range of the photoconductor. The wavelength of the semiconductor laser is mainly near infrared with an oscillation wavelength of about 780 nm. However, it is not limited to this wavelength, and a laser with an oscillation wavelength of 600 nm or a blue laser with an oscillation wavelength of 400 nm to 450 nm may also be used. In addition, a surface-emitting laser light source capable of outputting multiple beams is also effective for forming a color image.

[0090] -Developing device- The developing device 11 may be, for example, a general developing device that develops by contacting or non-contacting the developer. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and may be selected according to the purpose. For example, it may be a known developing device that has a function of attaching a one-component developer or a two-component developer to the photoconductor 7 using a brush, roller, or the like. Among them, it is preferable to use a developing roller that holds the developer on its surface.

[0091] The developer used in the developing device 11 may be a one-component developer containing only toner, or may be a two-component developer containing toner and a carrier. The developer may be magnetic or non-magnetic. Known developers are used.

[0092] -Cleaning device- The cleaning device 13 is a cleaning blade type device equipped with a cleaning blade 131. In addition to the cleaning blade type, a fur brush cleaning type or a simultaneous development and cleaning type may also be adopted.

[0093] -Transfer device- Examples of the transfer device 40 include known transfer chargers such as a contact type transfer charger using a belt, roller, film, rubber blade, etc., and a scorotron transfer charger or corotron transfer charger that utilizes corona discharge.

[0094] -Intermediate transfer body- A belt-like intermediate transfer belt containing semiconductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. is used as the intermediate transfer body 50. The intermediate transfer body may be in the form of a drum other than a belt.

[0095] FIG. 4 is a schematic diagram showing another example of the image forming apparatus according to the present embodiment. 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 photoconductor 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

[0096] Hereinafter, the embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" are by mass. In the following description, unless otherwise specified, synthesis, production, processing, measurement, etc. were carried out at room temperature (25°C ± 3°C).

[0097] <Manufacturing of charging rolls> [Example 1] -Preparing the support members- A cylindrical member made of SUM23L was electrolessly plated with nickel to a thickness of 5 μm, and then plated with hexavalent chromium to obtain a support member with a diameter of 8 mm.

[0098] - Formation of adhesive layer - Chlorinated polypropylene resin (maleic anhydride chlorinated polypropylene resin, Super Chlon 930, Nippon Paper Chemicals Co., Ltd.): 100 parts Epoxy resin (EP4000, ADEKA Corporation): 10 parts Conductive agent: Carbon black (Ketjen Black EC, Ketjen Black International Inc.): 2.5 parts Toluene or xylene: appropriate amount The above materials were mixed and processed in a ball mill for 1 hour to obtain a resin composition, which was then brushed onto the surface of a support member to form an adhesive layer having a thickness of 10 μm.

[0099] Epichlorohydrin rubber (Hydrin T3106, Zeon Corporation): 100 parts Electronic conductive agent: Carbon black (Asahi #60, Asahi Carbon Co., Ltd.): 6 parts Ion conductive agent (BTEAC, Lion Corporation): 5 parts Calcium carbonate (Whiten SB, Shiraishi Calcium Co., Ltd.): 20 parts Vulcanizing agent: Sulfur (Palnoc R, Ouchi Shinko Chemical Industry Co., Ltd.): 1 part Vulcanization accelerator: stearic acid (NOF Corporation): 1 part Vulcanization accelerator: Zinc oxide: 1.5 parts The above materials were mixed, kneaded using a tangential pressure kneader, and passed through a strainer to obtain a rubber composition. The rubber composition was kneaded with an open roll and formed into a roll shape using a molding machine on the surface of the adhesive layer. Then, it was heated in a heating furnace at a temperature of 175°C for 70 minutes to obtain an elastic layer. The diameter to the elastic layer was 12 mm.

[0100] - Formation of the outer layer - Binder resin: N-methoxymethylated nylon 1 (FR101, Lead City Co., Ltd.): 100 parts Conductive agent: Carbon black (volume average particle size 43 nm, MONAHRCH1000, Cabot): 15 parts Particles for forming unevenness: Polyamide particles (volume average particle size 10 μm, Orgasol2001EXDNat1, Arkema Co., Ltd.): 12 parts The above materials were mixed and diluted with methanol, and dispersed for 60 minutes using a bead mill and glass beads with a diameter of 1.3 mm at a propeller speed of 2000 rpm. The resulting dispersion was applied to the surface of the elastic layer by a blade coating method. It was then heated in a heating furnace at a temperature of 150°C for 30 minutes to form an outer layer with a thickness of 10 μm.

[0101] - Formation of protective layer - Silica-containing layer formation process The charging roll with the outer layer formed was attached to the drum cartridge of the image forming apparatus ApeosC7070 of FUJIFILM Business Innovation Co., Ltd. In this case, the charging roll was attached without the cleaning roll for the charging roll. The developer containing the toner with silica particles added to the outside was filled into the developing unit of the image forming apparatus. This image forming apparatus is a type in which a charging member contacts a photoconductor. In an environment of 10°C temperature and 15% relative humidity, 5,000 patch images with many scattered patches and a total image density of 5% were printed on A4-sized plain paper. Through this image formation, a silica-containing layer was formed on the surface of the outer layer of the charging roll. The charging roll with the silica-containing layer was removed from the image forming apparatus.

[0102] Surface treatment process The charged roll having the silica-containing layer was subjected to a surface treatment by immersing it for 30 minutes in alkaline electrolyzed water with a pH of 12. The charged roll was removed from the alkaline electrolyzed water and dried at room temperature for 24 hours to obtain a charged roll having a protective layer. The thickness, silica content, and silicon element concentration of the protective layer, as well as the water contact angle of the outer peripheral surface, were measured by the above-mentioned measuring methods.

[0103] [Example 2] A charging roll was manufactured in the same manner as in Example 1, except that the immersion time in the alkaline electrolytic water in the surface treatment step was changed to 3 minutes.

[0104] [Example 3] An electrostatic charge roll was manufactured in the same manner as in Example 1, except that the immersion time in the alkaline electrolytic water in the surface treatment step was changed to 30 seconds.

[0105] [Example 4] A charging roll was manufactured in the same manner as in Example 1, except that the number of patch images output in the silica-containing layer forming step was changed to 2000, and the immersion time in the alkaline electrolyzed water in the surface treatment step was changed to 30 seconds.

[0106] [Example 5] A charging roll was manufactured in the same manner as in Example 1, except that the number of patch images output in the silica-containing layer forming step was changed to 10,000, and the immersion time in the alkaline electrolyzed water in the surface treatment step was changed to 30 seconds.

[0107] [Comparative Example 1] A charging roll was produced in the same manner as in Example 1, except that the surface treatment step was not carried out.

[0108] [Comparative Example 2] A charging roll was manufactured in the same manner as in Example 1, except that in the surface treatment step, the alkaline electrolytic water was changed to ion-exchanged water.

[0109] [Comparative Example 3] A charging roll was manufactured in the same manner as in Example 1, except that the number of patch images output in the silica-containing layer forming step was changed to 500, and the immersion time in the alkaline electrolyzed water in the surface treatment step was changed to 30 seconds.

[0110] [Comparative Example 4] A charging roll was produced in the same manner as in Example 1, except that the silica-containing layer forming step was not carried out.

[0111] [Example 6] A charging roll was produced in the same manner as in Example 1, except that the silica-containing layer forming step was changed to the following plasma CVD.

[0112] Silica-containing layer formation process A parallel plate type plasma CVD apparatus was used. Using He as a carrier gas, TEOS (tetraethoxysilane), a film-forming raw material, was heated to 60°C, bubbled, and introduced into the chamber. The flow rate of TEOS was controlled by the bubbler pressure and carrier gas flow rate, and O2 was introduced as an oxidizing gas and He as a diluting gas. Discharge was generated at a high frequency of 13.56 MHz, and the film-forming temperature was set to 200°C, the reaction pressure was set to 1 Torr, and the flow rate was adjusted so that the film-forming rate was 100 nm / min, forming a silica-containing layer with a thickness of 5 μm.

[0113] <Performance evaluation of electrostatic components> The charging roll of each example was attached to a drum cartridge of an image forming apparatus Apeos C7070 manufactured by FUJIFILM Business Innovation Co., Ltd. This image forming apparatus is of a type in which a charging member contacts a photoconductor.

[0114] [Stain resistance (1)] In an environment with a temperature of 10°C and a relative humidity of 15%, 100,000 sheets of A3-sized plain paper were printed with a strip-shaped image of 100% image density and 320 mm length x 30 mm width. A 1 μm square area on the surface of the charging roll that contacted the band-like toner image on the photoreceptor was observed using a confocal laser microscope (OLS1100, manufactured by OLYMPAS Corporation), and the degree of contamination was classified as follows.

[0115] G0: Deposits were observed on the charging roll surface, and the area ratio of the deposits was 10% or less. G0.5: Deposition is observed on the charging roll surface, and the area ratio of the deposits is more than 10% and 20% or less. G1: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 20% and 30% or less. G2: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 30% and 40% or less. G3: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 40% and 50% or less.

[0116] [Stain resistance (2)] After the evaluation of contamination resistance (1), 100,000 copies of the same image were printed in the same environment. After that (i.e., after a total of 200,000 copies were printed), the surface of the charging roll was observed using the same observation method as in the evaluation of contamination resistance (1), and the degree of contamination was classified as follows:

[0117] G0: Deposits were observed on the charging roll surface, and the area ratio of the deposits was 10% or less. G0.5: Deposition is observed on the charging roll surface, and the area ratio of the deposits is more than 10% and 20% or less. G1: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 20% and 30% or less. G2: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 30% and 40% or less. G3: Deposits were observed on the charging roll surface, and the area ratio of the deposits was more than 40% and 50% or less.

[0118] [Cracks] After the evaluation of contamination resistance (2), the surface of the charging roll was observed with a laser microscope (model VK) manufactured by Keyence Corporation at a magnification of 50x objective lens. The number of cracks was counted in the entire outer peripheral surface area of ​​1 mm width at both ends in the axial direction, and classified as follows: A crack with a width of 5 μm or more and a length of 50 μm or more was considered to be a crack and was counted as "1 crack."

[0119] G0: 0 cracks G1: 1 to 4 cracks G2: 5 or more cracks

[0120] [Table 1]

[0121] The charging member, the method for producing the charging member, the charging device, the process cartridge, and the image forming apparatus according to the present disclosure include the following aspects.

[0122] (((1))) A support member; an elastic layer provided on the support member; an outer layer disposed on the elastic layer; a protective layer that is an outermost layer provided on the outer layer, The protective layer contains silica and has a silicon element concentration of 10 atomic % or more, The water contact angle of the outer surface is 35 degrees or less. Charged member. (((2))) The electrostatic charging member according to (((1))), wherein the outer peripheral surface has a contact angle with water of 25 degrees or less. (((3))) The electrostatic charging member according to (((1))) or (((2))), wherein the protective layer has a silicon element concentration of 20 atomic % or more and 33 atomic % or less. (((4))) The electrostatic charging member according to any one of (((1))) to (((3))), wherein the silica content in the protective layer is 25% by mass or more and 100% by mass or less. (((5))) The electrostatic charging member according to any one of (((1))) to (((4))), wherein the protective layer has a layer thickness of 1 μm or more and 10 μm or less. (((6))) A method for producing the electrostatic charging member according to any one of (((1))) to (((5))), comprising the steps of: providing a member having, in order, a support member, an elastic layer, an outer layer, and a layer containing silica; and contacting the silica-containing layer with alkaline electrolyzed water to provide a hydroxyl group on the surface of the silica-containing layer to form a protective layer. A method for manufacturing an electrostatic charging member. (((7))) A charging device comprising the charging member according to any one of (((1))) to (((5))). (((8))) A photoconductor; a charging device having the charging member according to any one of (((1))) to (((5))), the charging member contacting the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; A process cartridge that is detachably attached to an image forming apparatus. (((9))) A photoconductor; a charging device having the charging member according to any one of (((1))) to (((5))), the charging member contacting the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; a developing device for developing the electrostatic latent image formed on the surface of the photoconductor with a developer containing a toner to form a toner image; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising:

[0123] According to (((1))), (((4))) or (((5))), an electrostatic member is provided which is less susceptible to surface contamination and less susceptible to cracking in the outer layer even when used over a long period of time, compared to an electrostatic member in which the silicon concentration of the protective layer is less than 10 atomic % and the water contact angle of the outer peripheral surface exceeds 35 degrees. According to (((2))), an electrostatically charged member is provided whose surface is less susceptible to contamination even when used over a long period of time, compared with an electrostatically charged member whose outer peripheral surface has a water contact angle of more than 25 degrees. According to (((3))), an electrostatic member is provided in which cracks are less likely to occur in the outer layer even after long-term use, compared to an electrostatic member in which the silicon concentration in the protective layer is less than 20 atomic %. According to (((6))), a method for producing an electrostatic member is provided in which the surface is less susceptible to contamination and the outer layer is less susceptible to cracking even when used over a long period of time, compared to a production method in which the layer containing silica is not brought into contact with alkaline electrolytic water. According to (((7))), a charging device is provided that includes a charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to when the silicon concentration of the protective layer of the charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. According to (((8))), a process cartridge is provided that is equipped with a charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even with long-term use, compared to a case in which the silicon concentration of the protective layer of the charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. According to (((9))), an image forming apparatus is provided that is equipped with a charging member whose surface is less susceptible to contamination and whose outer layer is less susceptible to cracking even when used over a long period of time, compared to a case in which the silicon concentration of the protective layer of the charging member is less than 10 atomic % and the water contact angle of the outer peripheral surface is more than 35 degrees. [Explanation of symbols]

[0124] 30 charging member, 32 supporting member, 34 elastic layer, 36 outer layer, 38 protective layer

[0125] 7 photoconductor, 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 member (roll-shaped), 133 fibrous member (flat brush-shaped), 300 process cartridge

Claims

1. A support member; an elastic layer provided on the support member; an outer layer disposed on the elastic layer; a protective layer that is an outermost layer provided on the outer layer, The protective layer contains silica and has a silicon element concentration of 10 atomic % or more, The water contact angle of the outer peripheral surface is 35 degrees or less. Charged member.

2. 2. The charging member according to claim 1, wherein the contact angle of water on said outer peripheral surface is 25 degrees or less.

3. 2. The charging member according to claim 1, wherein the silicon element concentration in said protective layer is 20 atomic % or more and 33 atomic % or less.

4. 2. The charging member according to claim 1, wherein the silica content of the protective layer is from 25% by mass to 100% by mass.

5. 2. The charging member according to claim 1, wherein the protective layer has a thickness of from 1 [mu]m to 10 [mu]m.

6. A method for producing the electrostatic charging member according to any one of claims 1 to 5, comprising the steps of: providing a member having, in order, a support member, an elastic layer, an outer layer, and a layer containing silica; and contacting the silica-containing layer with alkaline electrolyzed water to provide a hydroxyl group on the surface of the silica-containing layer to form a protective layer. A method for manufacturing an electrostatic charging member.

7. A charging device comprising the charging member according to any one of claims 1 to 5.

8. A photoconductor; a charging device having the charging member according to any one of claims 1 to 5, the charging member contacting the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; A process cartridge that is detachably attached to an image forming apparatus.

9. A photoconductor; a charging device having the charging member according to any one of claims 1 to 5, the charging member contacting the surface of the photoconductor to charge the surface; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoconductor; a developing device for developing the electrostatic latent image formed on the surface of the photoconductor with a developer containing a toner to form a toner image; a transfer device for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising:

Images