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

Abstract

The invention discloses a conductive member, a charging device, a process cartridge, and an image forming apparatus. The conductive member has an area ratio of a particulate conductive portion of 15 area% or more as measured when a conductive point on a measurement surface of an atomic force microscope is measured while a current passes through the conductive member.

Description

Technical Field

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

[0002] Japanese Patent Publication No. 2011-022410 describes a conductive component comprising a substrate; an elastic layer disposed on the substrate; and a surface layer disposed on the elastic layer, the surface layer having a sea-island structure consisting of a sea portion comprising a first resin and an island portion comprising a second resin, and containing carbon black at least inside the island portion. Summary of the Invention

[0003] The present invention aims to provide a conductive member having excellent suppression of color streaks compared to a case where the area ratio of granular conductive portions measured when conducting points on a surface under atomic force microscopy are measured simultaneously with current flow is less than 15 area %, or the average area of ​​granular conductive portions measured when conducting points on a surface under atomic force microscopy are measured simultaneously with current flow is less than 0.05 μm. 2 .

[0004] According to a first aspect of the present invention, there is provided a conductive member wherein the area ratio of granular conductive portions measured when conductive points on a surface are measured by an atomic force microscope while passing an electric current is 15 area % or more.

[0005] According to a second aspect of the present invention, there is provided a conductive member wherein the average area of ​​the granular conductive portion measured when conducting points on the surface are measured by an atomic force microscope while passing an electric current is 0.05 μm 2 above.

[0006] According to a third aspect of the present invention, in the conductive member according to the first aspect, an area ratio of the conductive portion is 15 area % or more and 80 area % or less.

[0007] According to a fourth aspect of the present invention, in the conductive member according to the third aspect, an area ratio of the conductive portion is 30 area % or more and 60 area % or less.

[0008] According to a fifth aspect of the present invention, in the conductive member according to the first or second aspect, the average area of ​​the conductive portion is 0.05 μm 2 Above and 1.0μm 2 the following.

[0009] According to a sixth aspect of the present invention, in the conductive member according to the fifth aspect, the average area of ​​the conductive portion is 0.20 μm 2Above and 0.50μm 2 the following.

[0010] According to the seventh embodiment of the present invention, in the conductive component involved in any one of the first to sixth embodiments, when a current value is measured while applying -30V to a probe with a diameter of 100nm on the surface to move it, the area in which the current value flowing through a segment obtained by dividing a 50μm square area into a 256×256 grid and having a value of 60pA or more is more than 60% by area.

[0011] According to an eighth aspect of the present invention, the conductive member according to any one of the first to seventh aspects includes: a base material; an elastic layer provided on the base material; and a surface layer provided on the elastic layer.

[0012] According to a ninth aspect of the present invention, in the conductive member according to the eighth aspect, the surface layer contains a first resin, a second resin, and a conductive agent.

[0013] According to a tenth aspect of the present invention, in the conductive member according to the ninth aspect, the surface layer has a sea-island structure including a sea portion formed of the first resin and an island portion formed of the second resin.

[0014] According to an eleventh aspect of the present invention, there is provided a charging device including the conductive member according to any one of the first to tenth aspects.

[0015] According to a twelfth aspect of the present invention, there is provided a process cartridge including the charging device according to the eleventh aspect, wherein the process cartridge is attachable to and detachable from an image forming apparatus.

[0016] According to the thirteenth embodiment of the present invention, there is provided an image forming device comprising: an image retaining body; the charging device according to the eleventh embodiment, which charges the surface of the image retaining body; an electrostatic latent image forming device, which forms an electrostatic latent image on the surface of the image retaining body after charging; a developing device, which develops the electrostatic latent image formed on the surface of the image retaining body by a developer containing a colorant to form a colorant image; and a transfer device, which transfers the colorant image to the surface of a recording medium.

[0017] (Effect)

[0018] According to the first or eighth aspect, there is provided a conductive member having excellent suppression of color streaks compared to a case where the area ratio of granular conductive portions measured when conductive points on the surface are measured by atomic force microscopy while current is passed.

[0019] According to the second aspect, there is provided a conductive member having an average area of ​​less than 0.05 μm of granular conductive portions measured when conducting points on the surface are measured by an atomic force microscope while passing current. 2 Compared with the case of , the color streak generation suppression is excellent.

[0020] According to the third aspect, there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than when the area ratio of the conductive portion is less than 15 area % or exceeds 80 area %.

[0021] According to the fourth aspect, there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than when the area ratio of the conductive portion is less than 30 area % or exceeds 60 area %.

[0022] According to the fifth embodiment, a conductive component is provided, wherein the average area of ​​the conductive component and the conductive portion is less than 0.05 μm 2 or more than 1.0μm 2 Compared with the case of , the color stripe generation suppression is more excellent.

[0023] According to the sixth aspect, a conductive component is provided, wherein the average area of ​​the conductive component and the conductive portion is less than 0.20 μm. 2 or more than 0.50μm 2 Compared with the case of , the color stripe generation suppression is more excellent.

[0024] According to the seventh scheme, a conductive component is provided, which has better suppression of color streaks than the following situation: when -30V is applied to a probe with a diameter of 100nm on the surface to move it while measuring the current value, the area with a current value of 60pA or more flowing in a segment divided by dividing an area of ​​50μm square into a 256×256 grid is less than 60% by area.

[0025] According to the ninth or tenth aspect, there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than in a case where the surface layer contains only one type of resin.

[0026] According to the eleventh, twelfth, or thirteenth aspect, there is provided a charging device, a processing cartridge, or an image forming apparatus, which is superior in suppressing the occurrence of color fringes compared to a case where the conductive member includes the following conductive member: when an electric current is passed and the conductive points on the surface to be measured by an atomic force microscope are measured, the area ratio of the granular conductive parts is less than 15 area%, or when an electric current is passed and the conductive points on the surface to be measured by an atomic force microscope are measured, the average area of ​​the granular conductive parts is less than 0.05 μm. 2. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic perspective view showing an example of a conductive member according to the present embodiment;

[0028] Figure 2 is a schematic cross-sectional view showing an example of a conductive member according to this embodiment. Figure 1 AA cross-sectional view;

[0029] Figure 3 This is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are for illustrative purposes only and do not limit the scope of the invention.

[0031] In the numerical ranges described in this specification, the upper limit or lower limit of one numerical range may be replaced by the upper limit or lower limit of another numerical range described in this specification. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced by the value shown in the examples.

[0032] Each component may also include a plurality of corresponding substances.

[0033] When referring to the amount of each component in a composition, if there are multiple substances equivalent to each component in the composition, unless otherwise specified, the amount of each component refers to the total amount of the multiple substances present in the composition.

[0034] (Conductive parts)

[0035] In the first embodiment of the conductive member of the present embodiment, the area ratio of the granular conductive portion measured when conducting points on the surface are measured while passing an electric current using an atomic force microscope is 15 area % or more.

[0036] In the second embodiment of the conductive member of this embodiment, the average area of ​​the granular conductive portion measured when the conductive points on the surface were measured by atomic force microscopy while passing current was 0.05 μm. 2 above.

[0037] In this specification, unless otherwise specified, the term "conductive member of this embodiment" is used to describe both the first and second embodiments. Furthermore, unless otherwise specified, the term "conductive portion," "surface layer," etc. is used to describe both the first and second embodiments.

[0038] The conductive member of this embodiment can be preferably used as a charging member.

[0039] Conventional conductive members do not have sufficient granular conductive portions formed on the surface, resulting in charging defects and the problem of color streaks.

[0040] In the conductive member of this embodiment, the area ratio of the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while the current is passed is 15 area % or more, or the average area of ​​the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while the current is passed is 0.05 μm 2 As described above, there are many portions with low resistance values ​​on the surface, and it is presumed that the surface is sufficiently charged, thereby suppressing the occurrence of color stripes.

[0041] Next, the conductive member of this embodiment will be described in detail.

[0042] <Area Ratio and Average Area of ​​Granular Conductive Portions>

[0043] In the first embodiment of the conductive component of the present embodiment, the area ratio of the granular conductive part measured when the conductive points on the surface are measured by current simultaneous measurement atomic force microscopy (C-AFM) is 15 area% or more. From the viewpoint of suppressing the generation of color stripes and low resistance, it is preferably 15 area% or more and 80 area% or less, more preferably 20 area% or more and 70 area% or less, further preferably 30 area% or more and 60 area% or less, and particularly preferably 30 area% or more and 50 area% or less.

[0044] In the second embodiment of the conductive component of this embodiment, from the viewpoint of suppressing the generation of color stripes and low resistance, the area ratio of the granular conductive portion measured when measuring the conductive points on the surface by C-AFM is preferably 15 area % or more, more preferably 15 area % or more and 80 area % or less, further preferably 20 area % or more and 70 area % or less, particularly preferably 30 area % or more and 60 area % or less, and most preferably 30 area % or more and 50 area % or less.

[0045] In the second embodiment of the conductive member of this embodiment, when the conductive points on the surface were measured by C-AFM, the average area of ​​the granular conductive parts was 0.05 μm. 2 From the viewpoint of suppressing the occurrence of color fringes and low resistance, 0.05 μm is preferred. 2 Above and 1.0μm 2less than 0.10 μm, more preferably 0.10 μm 2 Above and 0.80μm 2 Below, more preferably 0.20 μm 2 Above and 0.50μm 2 Below, particularly preferably 0.30 μm 2 Above and 0.40μm 2 the following.

[0046] In the first embodiment of the conductive member of this embodiment, from the viewpoint of suppressing the occurrence of color fringes and low resistance, the average area of ​​the granular conductive portion measured when measuring the conductive points on the surface by C-AFM is preferably 0.05 μm 2 More than 0.05 μm 2 Above and 1.0μm 2 Below, more preferably 0.10 μm 2 Above and 0.80μm 2 Below, particularly preferably 0.20 μm 2 Above and 0.50μm 2 Below, most preferably 0.30 μm 2 Above and 0.40μm 2 the following.

[0047] In this embodiment, a method for measuring conductive points on the surface of a conductive member using a current-simultaneous atomic force microscope (C-AFM) is as follows.

[0048] Conductive dots were measured on the surface of the conductive component using a Hitachi High-Technologies Corporation AFM5200S (simultaneous AFM / current measurement) and a 110 μm CL scanner for S-image under the following conditions. Areas with a current of 60 pA or greater were defined as conductive regions, and the area ratio and average area of ​​the granular conductive regions were calculated.

[0049] Probe holder: Multiple holders

[0050] Cantilever: SI-DF20-R (100nm)

[0051] Bias voltage: -10V

[0052] Measuring range: 50μm×50μm

[0053] Data number X: 512 Y: 512

[0054] <Area ratio of the region with a current value of 60 pA or more>

[0055] With regard to the conductive component of the present embodiment, from the viewpoint of suppressing the generation of color stripes, when the current value is measured while applying -30 V to a probe with a diameter of 100 nm on the surface to move it, the area in which the current value of 60 pA or more flows through a segment obtained by dividing an area of ​​50 μm square (= 50 μm × 50 μm) into a grid of 256 × 256 is preferably 60% by area or more, more preferably 60% by area or more and 90% by area or less, further preferably 60% by area or more and 80% by area or less, and particularly preferably 65% ​​by area or more and 75% by area or less.

[0056] In addition, with regard to the conductive component of the present embodiment, from the perspective of suppressing the generation of color stripes, the area in which the current value flowing in the one segment is greater than 60 pA and less than 100 pA is preferably greater than 60 area%, more preferably greater than 60 area% and less than 90 area%, further preferably greater than 60 area% and less than 80 area%, and particularly preferably greater than 65 area% and less than 75 area%.

[0057] In this embodiment, the method for measuring the region on the surface of the conductive member where the current value is 60 pA or more is as follows.

[0058] On the surface of the resulting conductive component, the current simultaneous measurement atomic force microscope was used. While applying -30 V to a 100 nm diameter probe (cantilever) and moving it, a 50 μm square area was divided into 256 × 256 grids, and the current flowing in each segment was measured. Other measurement conditions were the same as those for the conductive dot measurement method.

[0059] From the viewpoint of charging properties and ease of production, the conductive member of this embodiment preferably includes a substrate, an elastic layer disposed on the substrate, and a surface layer provided on the elastic layer.

[0060] Furthermore, from the viewpoint of easiness in forming the granular conductive portion, the surface layer in the conductive member of the present embodiment preferably contains a first resin, a second resin, and a conductive agent.

[0061] Furthermore, from the viewpoint of easiness in forming the granular conductive portion, the surface layer in the conductive member of this embodiment more preferably has a sea-island structure consisting of a sea portion composed of the first resin and an island portion composed of the second resin.

[0062] Figure 1 It is a schematic perspective view showing an example of the conductive member according to this embodiment. Figure 2 This is a schematic cross-sectional view of an example of the conductive member according to this embodiment. Figure 2 yes Figure 1 AA cross-sectional view.

[0063] like Figure 1 and Figure 2 As shown, the conductive member 121A of this embodiment is a roller-shaped member including, for example, a shaft 30 (an example of a base material), an elastic layer 31 disposed on the outer peripheral surface of the shaft 30 , and a surface layer 32 disposed on the outer peripheral surface of the elastic layer 31 .

[0064] Hereinafter, each component of the conductive member of this embodiment will be described in detail, but the reference numerals attached to each component may be omitted.

[0065] <Base material>

[0066] The conductive member of this embodiment preferably includes a substrate.

[0067] The substrate is preferably a conductive cylindrical or columnar member. Here, conductivity means that the volume resistivity is less than 10 13 Ω·cm.

[0068] Examples of the material of the substrate include metals such as iron (free-cutting steel, etc.), copper, brass, stainless steel, aluminum, and nickel. Examples of the substrate include components with a plated outer surface (e.g., resin or ceramic components) and components with a conductive agent dispersed therein (e.g., resin or ceramic components).

[0069] <Elastic layer>

[0070] The conductive member of this embodiment preferably includes an elastic layer provided on the substrate.

[0071] The elastic layer preferably contains, for example, an elastic material and a conductive agent, and may further contain other additives.

[0072] Examples of the elastic material include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluororubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene-propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and rubber blends thereof. Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR, and rubber blends thereof are preferred. These elastic materials may be foamed or non-foamed.

[0073] Conductive agents include electronic conductive agents and ionic conductive agents. Examples of electronic conductive agents include carbon black such as Ketjen black and acetylene black; pyrolytic carbon and graphite; conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; conductive metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solutions, and tin oxide-indium oxide solid solutions; and powders of insulating materials treated to render their surfaces conductive. Examples of ionic conductive agents include onium perchlorates or chlorates such as tetraethylammonium and lauryltrimethylammonium; and alkali metal or alkaline earth metal perchlorates or chlorates such as lithium and magnesium. Conductive agents may be used alone or in combination of two or more.

[0074] Specific examples of carbon black include “Special Black 350” manufactured by Orion Engineered Carbons, “Special Black 100” manufactured by the same company, “Special Black 250” manufactured by the same company, “Special Black 5” manufactured by the same company, “Special Black 4” manufactured by the same company, “Special Black 4A” manufactured by the same company, “Special Black 550” manufactured by the same company, “Special Black 6” manufactured by the same company, “Color Black FW200” manufactured by the same company, “Color Black FW2” manufactured by the same company, and “Color Black FW2V” manufactured by the same company, “MONARCH 880” manufactured by Cabot Corporation, “MONARCH 1000” manufactured by the same company, “MONARCH 1300” manufactured by the same company, “MONARCH 1400” manufactured by the same company, “MOGUL-L” manufactured by the same company, and “REGAL 400R” manufactured by the same company.

[0075] The amount of the conductive agent blended is not particularly limited. However, in the case of an electronic conductive agent, the amount is preferably in the range of 1 part by mass to 30 parts by mass, and more preferably in the range of 15 parts by mass to 25 parts by mass, relative to 100 parts by mass of the elastic material. In the case of an ion conductive agent, the amount is preferably in the range of 0.1 parts by mass to 5.0 parts by mass, and more preferably in the range of 0.5 parts by mass to 3.0 parts by mass, relative to 100 parts by mass of the elastic material.

[0076] Examples of other additives that may be added to the elastic layer include softeners, plasticizers, curing agents, vulcanizers, vulcanization accelerators, antioxidants, surfactants, coupling agents, and fillers (such as silica and calcium carbonate), which are commonly used materials in elastic layers.

[0077] The average thickness of the elastic layer is preferably about 1 mm to about 15 mm, and more preferably about 2 mm to about 10 mm.

[0078] The volume resistivity of the elastic layer is preferably 10 3 Ω·cm or more and 10 14 Ω·cm or less.

[0079] <Surface layer>

[0080] The conductive member of this embodiment preferably includes a surface layer, and more preferably includes a surface layer provided on the elastic layer.

[0081] - Composition of the surface layer-

[0082] From the perspective of ease of forming a granular conductive portion, the surface layer preferably contains a first resin, a second resin, and a conductive agent, and more preferably has a sea-island structure consisting of a sea portion composed of the first resin and an island portion composed of the second resin, and contains a conductive agent.

[0083] Here, the "sea-island structure" refers to a structure in which at least two resins are mixed in a mutually incompatible state, and an island portion as a dispersed phase is contained in a sea portion as a continuous phase.

[0084] The sea-island structure is formed by adjusting the difference in solubility parameters (SP values) between the first and second resins and the mixing ratio of the first and second resins. To facilitate the formation of the sea-island structure, the difference in SP values ​​between the first and second resins is preferably 2 or more and 10 or less.

[0085] The mixing ratio of the first resin and the second resin will be described later.

[0086] The calculation method of the solubility parameter (SP value) is the method described in "Polymer Handbook 4th Edition John Wiley & Sons" VII680 to 683. The solubility parameters of major resins are described in VII702 to 711 of the above document.

[0087] Examples of the first resin include acrylic resins, cellulose resins, polyamide resins, copolymerized nylons, polyurethane resins, polycarbonate resins, polyester resins, polyethylene resins, polyvinyl resins, polyarylate resins, styrene-butadiene resins, melamine resins, epoxy resins, polyurethane resins, silicone resins, fluororesins (e.g., tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, polyvinylidene fluoride, etc.), urea-formaldehyde resins, and the like. Copolymerized nylons are copolymers containing one or more of 610 nylon, 11 nylon, and 12 nylon as polymer units, and may also contain 6 nylon, 66 nylon, etc. as other polymer units. As the first resin, an elastic material formulated in the elastic layer may also be used. As the first resin, a single resin may be used alone, or two or more resins may be used in combination.

[0088] From the perspectives of the electrical properties of the surface layer or its resistance to contamination; the moderate hardness or maintainability of the surface layer required due to the provision of the surface layer on the elastic layer; the dispersion adaptability or film forming properties of the conductive agent when forming the surface layer using a dispersion liquid, the first resin is preferably a polyamide resin (e.g., nylon), and more preferably a methoxymethylated polyamide resin (e.g., methoxymethylated nylon).

[0089] Examples of the second resin include polyvinyl butyral resin, polystyrene resin, and polyvinyl alcohol. As the second resin, one type of resin may be used alone, or two or more types of resins may be used in combination.

[0090] The second resin is preferably a polyvinyl butyral resin from the viewpoints of the electrical properties of the surface layer or its resistance to contamination; the appropriate hardness or maintainability of the surface layer required due to the provision of the surface layer on the elastic layer; the dispersion adaptability or coating film forming properties of the conductive agent when forming the surface layer using a dispersion liquid.

[0091] The content of the second resin is preferably 10 parts by mass or more and 30 parts by mass or less, more preferably 12 parts by mass or more and 28 parts by mass or less, and even more preferably 15 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the total of the first resin and the second resin.

[0092] By setting the content of the second resin to 10 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the total of the first and second resins, the conductive member further suppresses the occurrence of color fringes in the axial direction during image formation. The reason for this is presumably as follows.

[0093] By setting the second resin content to 10 parts by mass or greater relative to 100 parts by mass of the first and second resins combined, the percentage of islands in the surface layer increases. Consequently, the number of conductive paths in the surface layer increases. Furthermore, by setting the second resin content to 30 parts by mass or less relative to 100 parts by mass of the first and second resins combined, the percentage of islands in the surface layer does not become excessively high, allowing the islands to be dispersed in the surface layer in a nearly uniform manner.

[0094] The total content of the first resin and the second resin is preferably 50% by mass to 95% by mass, more preferably 60% by mass to 90% by mass, and even more preferably 70% by mass to 85% by mass, based on the entire surface layer.

[0095] Conductive agents include electronic conductive agents and ionic conductive agents. Examples of electronic conductive agents include carbon black such as Ketjen black and acetylene black; pyrolytic carbon and graphite; conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; conductive metal oxides such as tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solutions, and tin oxide-indium oxide solid solutions; and powders of insulating materials treated to render their surfaces conductive. Examples of ionic conductive agents include onium perchlorates or chlorates such as tetraethylammonium and lauryltrimethylammonium; and alkali metal or alkaline earth metal perchlorates or chlorates such as lithium and magnesium. Conductive agents may be used alone or in combination of two or more.

[0096] As the conductive agent, carbon black is preferred.

[0097] By using carbon black as the conductive agent, it is easier to obtain a conductive member that suppresses the occurrence of color fringes in the axial direction that occur during image formation. The reason for this is presumably as follows.

[0098] Carbon black is more likely to segregate near the island regions in the surface layer than conductive agents other than carbon black. Therefore, by setting the area occupancy of the island regions to between 10% and 45%, or by setting the diameter of the island regions to between 100 nm and 750 nm, the effect of increasing the number of conductive paths in the surface layer is further enhanced.

[0099] Based on the above, it is presumed that the use of carbon black as the conductive agent makes it easier to obtain a conductive member that suppresses the occurrence of color fringes in the axial direction that occur during image formation.

[0100] Examples of carbon black include Ketjen black, acetylene black, and oxidation-treated carbon black having a pH of 5 or less. More specifically, examples include “Special Black 350” manufactured by Orion Engineered Carbons, “Special Black 100” manufactured by the same company, “Special Black 250” manufactured by the same company, “Special Black 5” manufactured by the same company, “Special Black 4” manufactured by the same company, “Special Black 4A” manufactured by the same company, “Special Black 550” manufactured by the same company, “Special Black 6” manufactured by the same company, “Color Black FW200” manufactured by the same company, “Color Black FW2” manufactured by the same company, and “Color Black FW2V” manufactured by the same company, “MONARCH 880” manufactured by Cabot Corporation, “MONARCH 1000” manufactured by the same company, “MONARCH 1300” manufactured by the same company, “MONARCH 1400” manufactured by the same company, “MOGUL-L” manufactured by the same company, and “REGAL 400R” manufactured by the same company.

[0101] The average particle size of carbon black is preferably 15 nm to 30 nm, more preferably 15 nm to 25 nm, and even more preferably 15 nm to 20 nm.

[0102] By setting the average particle size of carbon black to 15 nm or more and 30 nm or less, it is easier to form a conductive member that suppresses the occurrence of color fringes in the axial direction that occur during image formation. The reason for this is presumably as follows.

[0103] By setting the average particle size of carbon black to between 15nm and 30nm, the carbon black particles are more closely packed together and tend to concentrate near the islands in the surface layer. This facilitates current flow through the conductive agent. Consequently, by setting the area occupancy of the islands to between 10% and 45%, or by setting the diameter of the islands to between 100nm and 750nm, the effect of increasing the number of conductive paths in the surface layer is further enhanced.

[0104] Based on the above, it is presumed that the conductive member is more likely to suppress the occurrence of color fringes in the axial direction that occur during image formation.

[0105] The average particle size of carbon black is a value measured by TEM (transmission electron microscope).

[0106] The measurement method is as follows.

[0107] First, the surface layer was cut with a microtome, and the obtained cross section was observed with a TEM (transmission electron microscope). The diameter of a circle equal to the projected area of ​​50 carbon black particles was defined as the particle size, and the average of these diameters was defined as the average particle size.

[0108] The content of the conductive agent is preferably 10 parts by mass or more and 15 parts by mass or less relative to 100 parts by mass of the total of the first resin and the second resin.

[0109] By setting the content of the conductive agent to 10 parts by mass or more and 15 parts by mass or less relative to 100 parts by mass of the total of the first resin and the second resin, the conductive member can more easily suppress the occurrence of color fringes in the axial direction during image formation. The reason for this is presumed as follows.

[0110] By setting the conductive agent content to 10 parts by mass or greater per 100 parts by mass of the first and second resins combined, the amount of conductive agent contained in the surface layer increases. This facilitates the proximity of the conductive agents, allowing current to flow more easily between them. Consequently, by setting the area occupancy of the islands to 10% to 45% or the diameter of the islands to 100 nm to 750 nm, the effect of increasing the number of conductive paths in the surface layer is further enhanced.

[0111] By setting the content of the conductive agent to 15 parts by mass or less relative to 100 parts by mass of the total of the first resin and the second resin, the conductive agent is less likely to be dispersed throughout the sea portion contained in the surface layer, thereby preventing the conductive path from being dispersed and the conductive effect from being reduced.

[0112] Based on the above, it is presumed that the conductive member is more likely to suppress the occurrence of color fringes in the axial direction that occur during image formation.

[0113] The surface layer preferably further comprises a silicon-containing compound.

[0114] The content of the silicon-containing compound is preferably 0.05 parts by mass or more and 0.15 parts by mass or less relative to 100 parts by mass of the total of the first resin and the second resin.

[0115] The surface layer further includes a silicon-containing compound, with the content of the silicon-containing compound being set to 0.05 parts by mass or more and 0.15 parts by mass or less relative to 100 parts by mass of the first and second resins combined. This suppresses the occurrence of axial color fringes during image formation. Furthermore, the conductive component exhibits improved stain resistance and fog suppression. The reasons for this are speculated as follows.

[0116] By setting the silicon-containing compound content to 0.05 parts by mass or greater relative to 100 parts by mass of the first and second resins combined, the surface roughness of the surface layer is appropriately reduced, improving the contamination resistance and fog suppression effects of the conductive component. Furthermore, by setting the silicon-containing compound content to 0.15 parts by mass or less relative to 100 parts by mass of the first and second resins combined, the electrical resistance of the surface layer is reduced.

[0117] The content of the silicon-containing compound is more preferably 0.075 parts by mass or more and 0.125 parts by mass or less, and even more preferably 0.09 parts by mass or more and 0.11 parts by mass or less, relative to 100 parts by mass of the total of the first resin and the second resin.

[0118] The content of the silicon-containing compound is measured using XPS (X-ray photoelectron spectrometer). As an X-ray photoelectron spectrometer, for example, ESCA-3400 manufactured by Shimadzu Corporation can be used.

[0119] Next, the procedure for measuring the content of the silicon-containing compound will be described.

[0120] The Si element is detected based on the peak position of photoelectrons excited by X-rays, and quantified based on the area intensity of each peak intensity.

[0121] The blending ratio of the first and second resins is determined based on the peak ratios of C═O and NH derived from amide bonds in the first resin and CO derived from butyral groups in the second resin, as detected by FT-IR (Fourier transform infrared spectroscopy), and the combined mass of the first and second resins is calculated. For example, the IRSpirit, manufactured by Shimadzu Corporation, can be used as an FT-IR instrument.

[0122] Examples of silicon-containing compounds include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylpolysiloxane; and modified silicone oils such as polyether-modified polysiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, methanol-modified polysiloxane, fluorine-modified polysiloxane, methacrylic acid-modified polysiloxane, mercapto-modified polysiloxane, and phenol-modified polysiloxane.

[0123] From the viewpoint of compatibility, the silicon-containing compound is preferably a polyether-modified polysiloxane.

[0124] The surface layer may also contain other additives.

[0125] As other additives formulated in the surface layer, well-known additives are used, for example, acid catalysts, softeners, plasticizers, curing agents, vulcanizing agents, vulcanization accelerators, antioxidants, surfactants, coupling agents, fillers (porous polyamide, silica, calcium carbonate, etc.), etc.

[0126] -Area ratio of island part-

[0127] When observing a cross section of the surface layer, the area ratio A of the island portion in a region A extending from the surface of the surface layer to a depth of 20% of the film thickness is 25% or more and 45% or less. From the viewpoint of suppressing a decrease in mechanical strength and suppressing the occurrence of color streaks, the area ratio A of the island portion is preferably 30% or more and 40% or less, and more preferably 35% or more and 40% or less.

[0128] When the area ratio of the island portions in the entire surface layer is within an appropriate range, it is easy to maintain mechanical strength and suppress the occurrence of color streaks.

[0129] Therefore, when observing the cross-section of the surface layer, from the viewpoint of suppressing the reduction in mechanical strength and suppressing the generation of color stripes, the area ratio B of the island portion in the region B at a depth exceeding 20% ​​of the film thickness from the surface of the surface layer is preferably greater than 40% and less than 50%, more preferably greater than 42.5% and less than 50%, and further preferably greater than 45% and less than 50%.

[0130] In addition, from the perspective of suppressing the reduction in mechanical strength and suppressing the generation of color stripes, the difference between the area ratio A of the island portion and the area ratio B of the island portion is preferably within 15% in absolute value, more preferably within 10%, and further preferably within 5%.

[0131] The area ratio of the island portion is a value measured as follows.

[0132] A slice sample of the surface layer cut in the thickness direction was prepared by the cryosection method, and a cross-section of the surface layer cut by the cryosection method in the slice sample was observed using a scanning electron microscope.

[0133] In the observed image, the area of ​​the region corresponding to region A, which extends from the surface of the surface layer to a depth of 20% of the film thickness, and the area of ​​the island portion in region A were measured. The ratio of the area of ​​the island portion in region A to the area of ​​the region corresponding to region A was calculated as the area ratio A of the island portion.

[0134] Similarly, the area of ​​the region corresponding to region B at a depth exceeding 20% ​​of the film thickness from the surface of the surface layer and the area of ​​the island in region B are measured, and the ratio of the area of ​​the island in region B to the area of ​​the region corresponding to region B is calculated as the area ratio B of the island.

[0135] -Island diameter-

[0136] For the conductive component of this embodiment, the diameter of the island portion on the cross section of the surface layer (any cross section in region A and region B) is preferably greater than 100 nm and less than 750 nm, more preferably greater than 150 nm and less than 650 nm, further preferably greater than 200 nm and less than 600 nm, and particularly preferably greater than 300 nm and less than 400 nm.

[0137] The diameter of the island portion is a value measured as follows.

[0138] A slice sample of the surface layer cut along the thickness direction was prepared by the cryosection method. The cross-section of the surface layer cut by the cryosection method in the slice sample was observed by scanning electron microscopy. Ten islands were randomly selected. For each of the ten islands, the maximum length (the so-called major diameter) between any two points on the contour line of the island was measured, and the average value of the ten major diameters was set as the diameter (nm) of the island.

[0139] -Surface roughness Rz of the outer peripheral surface of the surface layer-

[0140] The surface roughness Rz of the outer peripheral surface of the surface layer may be 8.0 μm or less.

[0141] Conventionally, if the surface roughness Rz of the outer peripheral surface of the surface layer exceeds 5.0 μm, blurring is likely to occur. However, in the conductive component of this embodiment, even if the surface roughness Rz of the outer peripheral surface of the surface layer exceeds 5.0 μm, blurring is suppressed as long as it is 8.0 μm or less.

[0142] Surface roughness Rz was measured at 23°C and 55% relative humidity using a contact-type surface roughness measuring instrument (Surfcom 570A, manufactured by Tokyo Seimitsu Co., Ltd.) and a contact probe with a diamond tip (5 μm R, 90° cone). The measurement distance was 2.5 mm, and the measurement location was from 5 mm to 7.5 mm from the end of the discharge region. Measurements were taken at four locations along the roller-shaped charging member at 90-degree increments around the circumference, including at both ends of the discharge region. The average value of the eight locations was calculated.

[0143] -Thickness of the surface layer-

[0144] The thickness of the surface layer is preferably 3 μm or more and 25 μm or less, more preferably 5 μm or more and 20 μm or less, and even more preferably 6 μm or more and 15 μm or less.

[0145] The thickness of the surface layer is measured by cutting the surface layer in the thickness direction and observing the obtained cross section with an optical microscope.

[0146] <Resistance Z of conductive components>

[0147] The conductive member of this embodiment preferably has a resistance Z measured by an impedance method of 4.5×10 5 Ω or less, more preferably 4.0×10 5 Ω or less, more preferably 3.5×10 5 Ω or less. In addition, the resistance Z is preferably 1.0×10 4 Ω or more, more preferably 5.0×10 4 Ω or above.

[0148] By setting the resistance Z measured by the impedance method within the above range, the ease of current flow in the entire conductive member is improved, thereby further suppressing the occurrence of color fringes in the axial direction during image formation.

[0149] The steps for measuring the resistance Z are as follows.

[0150] As a power supply and an ammeter, an SI 1260 impedance / gain phase analyzer (manufactured by Toyo Corporation) was used, and as a current amplifier, a 1296 dielectric interface (manufactured by Toyo Corporation) was used.

[0151] The substrate in the impedance measurement sample (conductive component) is set as the cathode, and the material with an aluminum plate with a width of 1.5 cm wrapped around the surface of the conductive component is set as the anode. An AC voltage of 1 Vp-p is applied from the high-frequency side within the frequency range of 1 MHz to 1 mHz, and the resistance Z of each sample is measured based on the AC impedance method.

[0152] <Method for manufacturing conductive member>

[0153] An example of a method for manufacturing the conductive member according to this embodiment will be described below.

[0154] A roll-shaped member having an elastic layer provided on the outer circumferential surface of a cylindrical or columnar substrate is prepared. The method for producing this roll-shaped member is not particularly limited. For example, a method can be used in which a mixture of a rubber material and, if necessary, a conductive agent and other additives is wound around a substrate and heated to vulcanize the mixture to form the elastic layer.

[0155] The method for forming the surface layer on the outer peripheral surface of the elastic layer is not particularly limited. Preferably, the surface layer is formed by applying a dispersion obtained by dissolving and dispersing the first resin, the second resin, and the conductive agent in a solvent to the outer peripheral surface of the elastic layer and then drying the applied dispersion. Examples of the method for applying the dispersion include knife coating, Meyer bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0156] Furthermore, the conductive member of this embodiment can be easily obtained by applying the dispersion to the outer peripheral surface of the elastic layer and setting the dew point of the environment during the step of drying the applied dispersion to 12°C or higher and 18°C ​​or lower. In general, the dew point of the environment during the step of drying the applied dispersion is approximately 5°C.

[0157] Furthermore, in the step of drying the applied dispersion, for example, by reducing the wind speed during drying by half, the conductive member of the present embodiment can be easily obtained.

[0158] <Applications of Conductive Components>

[0159] The conductive member of this embodiment is used, for example, in the following components: a charging roller for charging the surface of an image holder in electrophotographic copiers, electrostatic printers, and the like; a transfer roller for transferring a toner image formed on the image holder to a transfer medium; a toner transport roller for transporting toner to the image holder; a conductive roller for supplying power or driving power in combination with a conductive belt for electrostatically transporting paper; and a cleaning roller for removing toner from the image holder. Furthermore, the conductive member of this embodiment is used in inkjet image forming apparatuses, such as a power supply roller for charging an intermediate transfer member before ink is ejected from an inkjet head.

[0160] Among them, the conductive member of this embodiment is preferably used as a charging roller.

[0161] As described above, the conductive member 121A is described as a roller-shaped member as the conductive member of this embodiment. However, the conductive member of this embodiment is not limited thereto and may be an endless belt-shaped member or a sheet-shaped member.

[0162] In addition, the conductive component of this embodiment can also be a structure having, for example, an adhesive layer (primer layer) arranged between the substrate and the elastic layer, a resistance adjustment layer or migration prevention layer arranged between the elastic layer and the surface layer, and a coating layer (protective layer) arranged on the outside (outermost surface) of the surface layer.

[0163] (Charging Device, Image Forming Device, and Process Cartridge)

[0164] The charging device of this embodiment includes the conductive member of this embodiment.

[0165] The charging device of this embodiment is preferably a charging device that includes the conductive member of this embodiment and charges the image holding member by a contact charging method.

[0166] There is no particular restriction on the circumferential contact width between the conductive component and the image retaining body (i.e., the circumferential width of the conductive component in the area where the image retaining body contacts the conductive component). For example, it can be in the range of 0.5 mm to 5 mm, preferably in the range of 1 mm to 3 mm.

[0167] The process cartridge of this embodiment is detachably mounted on, for example, an image forming apparatus having the following structure, and includes a charging device for charging the surface of an image holding member.

[0168] The processing box of this embodiment may also be equipped with at least one selected from the group consisting of an image retaining body, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged image retaining body, a developing device for developing the latent image formed on the surface of the image retaining body by a colorant to form a colorant image, a transfer device for transferring the colorant image formed on the surface of the image retaining body to a recording medium, and a cleaning device for cleaning the surface of the image retaining body, as needed.

[0169] The image forming apparatus of this embodiment includes an image holder, a charging device for charging the surface of the image holder, an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image holder, a developing device for developing the electrostatic latent image formed on the surface of the image holder using a developer containing toner to form a toner image, and a transfer device for transferring the toner image onto the surface of a recording medium. The charging device described above in this embodiment is employed as the charging device.

[0170] Next, an image forming apparatus and a process cartridge according to this embodiment will be described with reference to the drawings.

[0171] Figure 3 1 is a schematic diagram showing the configuration of an image forming apparatus according to the present embodiment.

[0172] like Figure 3 As shown, image forming apparatus 210 includes an image forming apparatus main body 211 that houses various components. Disposed within image forming apparatus main body 211 are a storage unit 212 for storing recording media P, such as paper, an image forming unit 214 for forming an image on the recording media P, a transport unit 216 for transporting the recording media P from storage unit 212 to image forming unit 214, and a control unit 220 for controlling the operation of various components of image forming apparatus 210. Furthermore, a discharge unit 218 is disposed at the top of image forming apparatus main body 211 to discharge the recording media P on which the image has been formed by image forming unit 214.

[0173] The image forming unit 214 includes image forming units 222Y, 222M, 222C, and 222K (hereinafter referred to as 222Y to 222K) that form toner images of yellow (Y), magenta (M), cyan (C), and black (K), an intermediate transfer belt 224 (an example of a transfer target) to which the toner images formed by the image forming units 222Y to 222K are transferred, a first transfer roller 226 (an example of a transfer roller) that transfers the toner images formed by the image forming units 222Y to 222K to the intermediate transfer belt 224, and a second transfer roller 228 (an example of a transfer member) that transfers the toner images transferred to the intermediate transfer belt 224 by the first transfer roller 226 from the intermediate transfer belt 224 to a recording medium P. The image forming unit 214 is not limited to the above-described configuration and may have other configurations as long as it forms an image on the recording medium P (an example of a transfer target).

[0174] Here, a unit composed of the intermediate transfer belt 224, the first transfer roller 226, and the second transfer roller 228 corresponds to an example of a transfer device. Alternatively, this unit may be referred to as a cartridge (process cartridge).

[0175] The image forming units 222Y to 222K are arranged side by side in a vertically central portion of the image forming apparatus 210 in a state tilted relative to the horizontal direction. Figure 3 The photosensitive body 232 (an example of an image holding body) rotates in the clockwise direction. In addition, since the image forming units 222Y to 222K are constructed in the same manner, Figure 3 In FIG. 1 , reference numerals of the components of the image forming units 222M, 222C, and 222K are omitted.

[0176] Around each photoreceptor 232, there are arranged in sequence, starting from the upstream side in the rotation direction of the photoreceptor 232, a charging device 223 having a charging roller 223A (an example of a charging component) for charging the photoreceptor 232, an exposure device 236 (an example of an electrostatic latent image forming device) for exposing the photoreceptor 232 charged by the charging device 223 to form an electrostatic latent image on the photoreceptor 232, a developing device 238 for developing the latent image formed on the photoreceptor 232 by the exposure device 236 to form a colorant image, and a removal component (cleaning scraper, etc.) 240 that contacts the photoreceptor 232 to remove the colorant remaining on the photoreceptor 232.

[0177] Here, the photoreceptor 232 , the charging device 223 , the exposure device 236 , the developing device 238 , and the removing member 240 are integrally held by a housing (frame) 222A to form a cartridge (process cartridge).

[0178] A self-scanning LED print head is applied to the exposure device 236. Alternatively, the exposure device 236 may be an exposure device of an optical system that exposes the photoreceptor 232 from a light source via a polygonal mirror.

[0179] The exposure device 236 forms a latent image based on the image signal transmitted from the control section 220. The image signal transmitted from the control section 220 may be, for example, an image signal acquired by the control section 220 from an external device.

[0180] The developing device 238 includes a developer supply body 238A that supplies developer to the photoreceptor 232 , and a plurality of conveying members 238B that convey the developer supplied to the developer supply body 238A while stirring the developer.

[0181] The intermediate transfer belt 224 is formed into an endless shape and is arranged above the image forming units 222Y to 222K. Winding rollers 242 and 244 are provided on the inner circumference of the intermediate transfer belt 224 to wind the intermediate transfer belt 224. The intermediate transfer belt 224 is rotated by one of the winding rollers 242 and 244, and is moved in one direction (for example, Figure 3 In addition, the winding roller 242 is provided as a counter roller facing the second transfer roller 228.

[0182] The first transfer roller 226 faces the photoreceptor 232 across the intermediate transfer belt 224. A first transfer position is provided between the first transfer roller 226 and the photoreceptor 232, where the toner image formed on the photoreceptor 232 is transferred to the intermediate transfer belt 224.

[0183] The second transfer roller 228 faces the winding roller 242 across the intermediate transfer belt 224. A second transfer position for transferring the toner image transferred onto the intermediate transfer belt 224 to the recording medium P is provided between the second transfer roller 228 and the winding roller 242.

[0184] The conveying section 216 is provided with a feed roller 246 for feeding out the recording medium P accommodated in the accommodation section 212, a conveying path 248 for conveying the recording medium P fed by the feed roller 246, and a plurality of conveying rollers 250 arranged along the conveying path 248 and conveying the recording medium P fed by the feed roller 246 to the second transfer position.

[0185] A fixing device 260 is provided downstream of the second transfer position in the conveyance direction. The fixing device 260 fixes the toner image formed on the recording medium P by the image forming unit 214 to the recording medium P.

[0186] The fixing device 260 includes a heating roller 264 for heating the image on the recording medium P and a pressure roller 266 as an example of a pressure member. A heat source 264B is provided inside the heating roller 264 .

[0187] Discharge rollers 252 are provided on the downstream side of the fixing device 260 in the conveying direction to discharge the recording medium P on which the toner image is fixed, to the discharge section 218 .

[0188] Next, an image forming operation of forming an image on the recording medium P in the image forming apparatus 210 will be described.

[0189] In the image forming apparatus 210 , the recording medium P fed out from the storage portion 212 by the feed roller 246 is fed into the second transfer position by the plurality of transport rollers 250 .

[0190] Meanwhile, in the image forming units 222Y to 222K, the photoreceptors 232 charged by the charging device 223 are exposed by the exposure device 236, forming latent images on the photoreceptors 232. This latent image is developed by the developing device 238, forming a toner image on the photoreceptors 232. The toner images of the respective colors formed by the image forming units 222Y to 222K are superimposed on the intermediate transfer belt 224 at the primary transfer position, forming a color image. The color image formed on the intermediate transfer belt 224 is then transferred to the recording medium P at the secondary transfer position.

[0191] The recording medium P with the transferred toner image is conveyed to the fixing device 260, where the transferred toner image is fixed by the fixing device 260. The recording medium P with the fixed toner image is discharged by the discharge roller 252 to the discharge section 218. As described above, a series of image forming operations are performed.

[0192] In addition, the image forming device 210 of this embodiment is not limited to the above-mentioned structure. For example, a well-known image forming device such as an image forming device using a direct transfer method that directly transfers the colorant image formed on each photosensitive body 232 of the image forming units 222Y~222K to the recording medium P may also be adopted.

[0193] [Example]

[0194] The following examples are described, but the present embodiment is not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0195] (Example 1: Fabrication of Conductive Component)

[0196] <Formation of elastic layer>

[0197] A mixture of 15 parts by mass of a conductive agent (carbon black, Asahi Thermal, manufactured by Asahi Carbon Co., Ltd.), 1 part by mass of a vulcanizing agent (sulfur, 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.) as an additional additive to be added to the elastic layer, and 2.0 parts by mass of a vulcanization accelerator (Nocceler DM, manufactured by Ouchi Shinko Chemical Co., Ltd.) as an additional additive to be added to the elastic layer, was kneaded using an open roller to obtain an elastic layer-forming composition. The elastic layer-forming composition was then wound onto the outer circumference of an 8 mm diameter SUS303 shaft (substrate) via an adhesive layer using a press molding machine. The roller was then placed in an oven at 180°C and heated for 30 minutes to form a 3.5 mm thick elastic layer on the shaft. The outer circumference of the elastic layer was then polished to obtain a 14 mm diameter conductive elastic roller having a 3.0 mm thick elastic layer.

[0198] (Formation of Surface Layer)

[0199] 15 parts by mass of a composition consisting of 76 parts by mass of a polyamide resin (N-methoxymethylated nylon, F30K manufactured by Nagase Chemtex Co., Ltd.) as a first resin, 24 parts by mass of a polyvinyl butyral resin (S-LEC BL-1 manufactured by Sekisui Chemical Co., Ltd.) as a second resin, 13 parts by mass of carbon black (MONARCH 1000 manufactured by Cabot Corporation) as a conductive agent, 10 parts by mass of a porous polyamide filler (ORGASOL 2001UD NAT 1 manufactured by Arkema) as a filler, 1.0 part by mass of an acid catalyst (NACURE 4167 manufactured by King Industry Co., Ltd.), and 0.025 parts by mass of a leveling agent (polyether-modified polydimethylsiloxane as a polyether-modified polysiloxane, BYK307 manufactured by BYK) was diluted with 85 parts by mass of methanol and dispersed using a bead mill to obtain a dispersion. The obtained dispersion was dip-coated on the outer peripheral surface of the elastic layer of a conductive elastic roller under an environment of a temperature of 24°C and a dew point of 14°C, air-dried, and then heated at 140°C for 30 minutes for crosslinking to form a surface layer with a thickness of 10 μm, thereby obtaining a conductive member.

[0200] (Comparative Example 1)

[0201] During the air drying in the formation of the surface layer, the same procedure as in Example 1 was carried out except that the dew point was set at 5° C. to obtain a conductive member.

[0202] (Example 2 to Example 8)

[0203] As shown in Table 1, a conductive member was obtained in the same manner as in Example 1 except that the coating environment (dew point) and the addition amounts of the first resin and the second resin were changed.

[0204] (Example 9)

[0205] During air drying in the formation of the surface layer, the same procedure as in Example 1 was carried out except that the air volume in the coating chamber was halved to obtain a conductive member.

[0206] (Example 10)

[0207] During the air drying in the formation of the surface layer, the same procedure as in Example 1 was carried out except that the air volume in the coating chamber was further reduced to obtain a conductive member.

[0208] The following properties of the conductive member obtained in each example were measured by the above-mentioned method. The obtained results are shown in Table 2.

[0209] Conductive point measurement using a current-conducting atomic force microscope (C-AFM)

[0210] The conductive spots on the surface of the resulting conductive member were measured under the following conditions using a Hitachi High-Technologies Corporation AFM5200S (simultaneous AFM / current measurement) and an S-image CL scanner (110 μm). Areas with a current of 60 pA or greater were defined as conductive regions, and the area ratio and average area of ​​the granular conductive regions were calculated. The measurement results are shown in Table 2.

[0211] Probe holder: Multiple holders

[0212] Cantilever: SI-DF20-R (100nm)

[0213] Bias voltage: -10V

[0214] Measuring range: 50μm×50μm

[0215] Data number X: 512 Y: 512

[0216] <Ratio of the region with a current value of 60 pA or more>

[0217] On the surface of the obtained conductive component, the current is measured simultaneously using an atomic force microscope. While applying -30 V to a probe (cantilever) with a diameter of 100 nm to move it, an area of ​​50 μm square (= 50 μm × 50 μm) is divided into 256 × 256 grids, and the current value flowing in each segment is measured.

[0218] Table 2 shows the area ratio of the segment having a current value of 60 pA or more in each segment.

[0219] <Measurement of the electrical resistance Z of the conductive member>

[0220] An SI 1260 impedance / gain phase analyzer (manufactured by Toyo Technica Co., Ltd.) was used as a power supply and an ammeter, and a 1296 dielectric interface (manufactured by Toyo Technica Co., Ltd.) was used as a current amplifier.

[0221] The substrate in the impedance measurement sample (conductive component) is set as the cathode, and the material with an aluminum plate with a width of 1.5 cm wrapped around the surface of the conductive component is set as the anode. An AC voltage of 1 Vp-p is applied from the high-frequency side in the frequency range from 1 MHz to 1 mHz, and the resistance Z of each sample is measured based on the AC impedance method.

[0222] <Evaluation>

[0223] -Color stripe evaluation-

[0224] The conductive member obtained in Examples or Comparative Examples was incorporated as a charging roller in a modified image forming apparatus (DocuCentre-V C7776, manufactured by Fujifilm Business Innovation Co., Ltd.), and 5,000 A4 images with an image density of 30% were output under conditions of 28°C and 85% RH.

[0225] The level of color streaks extending in the axial direction of the photoreceptor, which occurred in the image output on the 5,000th sheet, was evaluated as G0 to G3. G0 to G2 were levels with no problems in use. The evaluation results are shown in Table 2.

[0226] G0: Generation of color fringes extending in the axial direction of the photoreceptor was not observed.

[0227] G0.5: The number of color fringes extending in the axial direction of the photoreceptor is one or less.

[0228] G1: The number of color stripes extending in the axial direction of the photoreceptor is 2 or more and 4 or less.

[0229] G1.5: The number of color fringes extending in the axial direction of the photoreceptor is 5 or more and 7 or less.

[0230] G2: The number of color stripes extending in the axial direction of the photoreceptor is 8 or more and 10 or less.

[0231] G2.5: The number of color fringes extending in the axial direction of the photoreceptor is 11 or more and 13 or less.

[0232] G3: There are 14 or more color stripes extending in the axial direction of the photoreceptor.

[0233] - Mechanical Strength Evaluation -

[0234] The mechanical strength of the surface layer was evaluated by the MIT test.

[0235] The MIT test is based on JIS P 8115:2001 (MIT testing machine method).

[0236] Specifically, a strip-shaped test piece having a circumferential width of 15 mm and a length of 200 mm was cut out from the surface layer of the conductive member (the thickness of the test piece was set to the thickness of the surface layer).

[0237] The two ends of the strip test piece are fixed, a tensile force of 1 kgf is applied, and the strip test piece is repeatedly bent (folded) in 90° directions to the left and right using a fixture with a curvature radius R = 0.05 as a fulcrum. The number of bends at which the strip test piece breaks is defined as the folding endurance. Based on the folding endurance, the strength is evaluated according to the following evaluation criteria.

[0238] Furthermore, the MIT test was performed under an environment of a temperature of 22° C. and a humidity of 55% RH.

[0239] The evaluation results are shown in Table 2.

[0240] G0: The folding endurance is more than 100,000 times.

[0241] G1: The folding endurance is more than 50,000 times and less than 100,000 times.

[0242] G2: The folding endurance is more than 10,000 times and less than 50,000 times.

[0243] G3: Folding times are less than 10,000 times.

[0244] [Table 1]

[0245]

[0246] [Table 2]

[0247]

[0248] The abbreviations in Tables 1 and 2 are as follows.

[0249] -First Resin-

[0250] PA1: Polyamide resin (F30K manufactured by Nagase Chemtex Co., Ltd.)

[0251] -Second Resin-

[0252] PVB1: Polyvinyl butyral resin (S-LEC BM-1, manufactured by Sekisui Chemical Co., Ltd.)

[0253] -Conductive agent-

[0254] CB1: Carbon black (MONARCH 1000, manufactured by Cabot Corporation)

[0255] -filler-

[0256] F1: porous polyamide filler (ORGASOL 2001UD NAT 1, manufactured by Arkema)

[0257] -Acid Catalyst-

[0258] CAT1: Amine-neutralized phosphoric acid catalyst (NACURE 4167, manufactured by King Industry Co., Ltd.)

[0259] -Silicon-containing compounds-

[0260] LA1: Polyether-modified polydimethylsiloxane (BYK307, manufactured by BYK) as a polyether-modified polysiloxane

[0261] The above results show that the conductive member of this example is superior in suppressing the occurrence of color streaks compared to the conductive member of the comparative example.

[0262] (Note)

[0263] (((1)))A conductive component, wherein

[0264] The area ratio of the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while passing an electric current is 15 area % or more.

[0265] (((2)))A conductive component, wherein

[0266] The average area of ​​the granular conductive parts measured by atomic force microscopy while measuring the conductive points on the surface through current is 0.05 μm. 2 above.

[0267] (((3))) The conductive component according to (((1))), wherein

[0268] The area ratio of the conductive portion is 15 area % or more and 80 area % or less.

[0269] (((4))) The conductive component according to (((3))), wherein

[0270] The area ratio of the conductive portion is 30 area % or more and 60 area % or less.

[0271] (((5)))The conductive component according to (((1))) or (((2))), wherein

[0272] The average area of ​​the conductive portion is 0.05 μm 2 Above and 1.0μm 2 the following.

[0273] (((6))) The conductive component according to (((5))), wherein

[0274] The average area of ​​the conductive portion is 0.20 μm 2 Above and 0.50μm 2 the following.

[0275] (((7))) The conductive component according to any one of (((1))) to (((6))), wherein

[0276] When a probe with a diameter of 100 nm was moved while applying -30 V on the surface and measuring the current value, a current of 60 pA or higher flowed through a segment obtained by dividing a 50 μm square area into a 256×256 grid, accounting for 60% or more of the area.

[0277] (((8))) The conductive component according to any one of (((1))) to (((7))), wherein

[0278] The invention comprises a base material, an elastic layer provided on the base material, and a surface layer provided on the elastic layer.

[0279] (((9))) The conductive component according to (((8))), wherein

[0280] The surface layer includes a first resin, a second resin, and a conductive agent.

[0281] (((10)))The conductive component according to (((9))), wherein

[0282] The surface layer has a sea-island structure including a sea portion formed of the first resin and an island portion formed of the second resin.

[0283] (((11)))A charging device, wherein:

[0284] A conductive member according to any one of (((1))) to (((10))) is provided.

[0285] (((12)))A processing box, wherein

[0286] (((11))) The above-mentioned charging device is provided, and the process cartridge is attachable to and detachable from the image forming apparatus.

[0287] (((13)))An image forming apparatus comprising:

[0288] An image retaining body; a charging device as described in (((11))), which charges the surface of the image retaining body; an electrostatic latent image forming device, which forms an electrostatic latent image on the surface of the charged image retaining body; a developing device, which develops the electrostatic latent image formed on the surface of the image retaining body with a developer containing a colorant to form a colorant image; and a transfer device, which transfers the colorant image to the surface of a recording medium.

[0289] According to (((1))) or (((8))), a conductive component is provided which has excellent suppression of color streak generation compared to a case where the area ratio of the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while passing an electric current is less than 15 area%.

[0290] According to (((2))), there is provided a conductive member having an average area of ​​less than 0.05 μm of granular conductive portions measured when conductive points on the surface are measured by atomic force microscopy while passing current. 2 Compared with the case of , the color streak generation suppression is excellent.

[0291] According to (((3))), there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than when the area ratio of the conductive portion is less than 15 area % or exceeds 80 area %.

[0292] According to (((4))), there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than when the area ratio of the conductive portion is less than 30 area % or exceeds 60 area %.

[0293] According to (((5))), there is provided a conductive member having an average area with the conductive portion of less than 0.05 μm 2 or more than 1.0μm 2 Compared with the case of , the color stripe generation suppression is more excellent.

[0294] According to (((6))), there is provided a conductive member having an average area of ​​less than 0.20 μm with the conductive portion. 2 or more than 0.50μm 2 Compared with the case of , the color stripe generation suppression is more excellent.

[0295] According to (((7))), a conductive component is provided which has a more excellent ability to suppress the generation of color stripes than in the following case: when a probe with a diameter of 100 nm is applied to the surface and the current value is measured while being moved, the area in which the current value flowing through a segment obtained by dividing an area of ​​50 μm square into a grid of 256×256 is 60 pA or more is less than 60% by area.

[0296] According to (((9))) or (((10))), there is provided a conductive member having a more excellent ability to suppress the occurrence of color streaks than in a case where the surface layer contains only one type of resin.

[0297] According to (((11))), (((12))) or (((13))), there is provided a charging device, a processing box or an image forming device, which is superior in suppressing the generation of color fringes compared to a case where the conductive member includes the following conductive member: the area ratio of the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while an electric current is passed is less than 15 area%, or the average area of ​​the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while an electric current is passed is less than 0.05 μm 2 .

Claims

1. A conductive component, characterized in that The area ratio of the granular conductive portion measured when the conductive points on the surface are measured by an atomic force microscope while passing an electric current is 15 area % or more.

2. A conductive component, characterized in that The average area of ​​the granular conductive parts measured by atomic force microscopy while measuring the conductive points on the surface through current is 0.05 μm. 2 above.

3. The conductive component according to claim 1, wherein The area ratio of the conductive portion is 15 area % or more and 80 area % or less. The conductive component according to claim 3 , wherein The area ratio of the conductive portion is 30 area % or more and 60 area % or less.

5. The conductive component according to claim 1 or 2, wherein The average area of ​​the conductive portion is 0.05 μm 2 Above and 1.0μm 2 the following. The conductive component according to claim 5 , wherein The average area of ​​the conductive portion is 0.20 μm 2 Above and 0.50μm 2 the following.

7. The conductive member according to any one of claims 1 to 6, wherein When a probe with a diameter of 100 nm was moved while applying -30 V on the surface and measuring the current value, a current of 60 pA or higher flowed through a segment obtained by dividing a 50 μm square area into a 256×256 grid, accounting for 60% or more of the area.

8. The conductive member according to any one of claims 1 to 7, wherein The invention comprises a base material, an elastic layer provided on the base material, and a surface layer provided on the elastic layer.

9. The conductive component according to claim 8, wherein The surface layer includes a first resin, a second resin, and a conductive agent.

10. The conductive member according to claim 9, wherein The surface layer has a sea-island structure including a sea portion formed of the first resin and an island portion formed of the second resin.

11. A charging device, characterized in that: A conductive member according to any one of claims 1 to 10 is provided.

12. A process cartridge, characterized in that: The charging device according to claim 11 is provided, wherein the process cartridge is attachable to and detachable from the image forming apparatus.

13. An image forming apparatus, characterized in that: have: Image holding body; The charging device according to claim 11, wherein the charging device charges the surface of the image holding member; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image holding member; a developing device for developing the electrostatic latent image formed on the surface of the image holding member with a developer containing toner to form a toner image; as well as A transfer device transfers the toner image to a surface of a recording medium.

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