JP2019061045A - Charging member, method for manufacturing charging member, process cartridge, and image forming apparatus - Google Patents

Abstract

To provide a charging member that is excellent in image quality maintaining property for a long period regardless of environment.SOLUTION: A charging member has a conductive support and at least an elastic layer on the conductive support. The elastic layer contains conductive carbon, epichlorohydrin rubber, and rubber material other than epichlorohydrin rubber, and the mass ratio of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is larger than the mass ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charging member, a method of manufacturing the charging member, a process cartridge, and an image forming apparatus.

In an image forming apparatus using an electrophotographic method, an image carrier (electrophotographic photosensitive member) is charged by a charging device or the like to form a charge, and an electrostatic latent image is formed by a laser or the like which modulates an image signal, The electrostatic latent image is developed with charged toner to form a toner image. Then, the toner image is transferred to a recording medium directly or through an intermediate transfer member to obtain a desired image.
In this image forming apparatus, a non-contact type charging device such as corotron or scorotron charged by corona discharge generated by applying a high voltage to a conventional metal wire is known as a charging device. However, in recent years, instead of this, a charging device using a charging roll has been widely used because the voltage to be applied is generally small and the amount of generated ozone is also small.

Further, as a composition for forming the elastic layer of the charging member, Patent Document 1 discloses a sea-island structure comprising a polymer continuous phase made of an ion conductive rubber material and a polymer particle phase made of an electron conductive rubber material. A rubber composition, wherein the ion conductive rubber material is mainly made of a raw material rubber A having a volume resistivity of 1 × 10 ¹² Ω · cm or less, and the electroconductive rubber material is made of a raw material rubber B with conductive particles. A semiconductive rubber composition is disclosed which is characterized in that it is made conductive by blending it.

Furthermore, as a conductive member used as a charging member, Patent Document 2 is a conductive member in which at least a conductive elastic layer is formed on the outer periphery of a conductive support, and the conductive elastic layer is Component (C) is contained in an amount of 5 to 80 parts by mass with the following components (A) to (C) as essential components and 100 parts by mass of the total amount of components (A) and (B) A conductive member characterized by being formed of a rubber composition contained therein is disclosed.
(A) Epichlorohydrin rubber (B) acrylonitrile-butadiene rubber (C) electroconductive conductive agent

JP 2002-3651 A Unexamined-Japanese-Patent No. 2004-211062

  Therefore, the object of the present invention is that the elastic layer contains a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the mass ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer The image quality maintenance over a long period regardless of the environment compared with the one having the same or less mass ratio of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer rather than the elastic layer An object of the present invention is to provide a charging member which is excellent in elasticity.

The above-mentioned subject is solved by the following means.
The invention according to claim 1 is
A conductive support and at least an elastic layer on the conductive support, the elastic layer containing conductive carbon, epichlorohydrin rubber and a rubber material other than epichlorohydrin rubber, and the elastic layer per unit volume of the elastic layer The charging member is a charging member in which the mass proportion of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is larger than the mass proportion of the conductive carbon present in the epichlorohydrin rubber.

The invention according to claim 2 is
The charging member according to claim 1, wherein the rubber material other than the epichlorohydrin rubber is at least one rubber selected from the group consisting of acrylonitrile butadiene rubber, styrene butadiene rubber, and chloroprene rubber.

The invention according to claim 3 is
The charging member according to claim 2, wherein the rubber material other than the epichlorohydrin rubber is acrylonitrile butadiene rubber.

The invention according to claim 4 is
The charging member according to claim 3, wherein an acrylonitrile content of the acrylonitrile butadiene rubber is 25% by mass or less.

The invention according to claim 5 is
The content of the conductive carbon in the elastic layer is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber. The charging member according to any one of the above.

The invention according to claim 6 is
The charging according to claim 5, wherein the content of the conductive carbon in the elastic layer is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber. It is a member.

The invention according to claim 7 is
The charging member according to any one of claims 1 to 6, wherein the elastic layer further contains an ion conductive agent.

The invention according to claim 8 is
At least one selected from the group consisting of quaternary ammonium salt compounds, alkali metal or alkaline earth metal salts of perchloric acid, and alkali metal or alkaline earth metal salts of chloric acid It is a charging member according to claim 7, which is a compound.

The invention according to claim 9 is
After each of the step of dispersing conductive carbon in epichlorohydrin rubber and the step of dispersing conductive carbon in a rubber material other than epichlorohydrin rubber, epichlorohydrin rubber containing the conductive carbon and epichlorohydrin containing the conductive carbon are provided. The method of manufacturing a charging member according to any one of claims 1 to 8, further comprising the step of mixing with a rubber material other than rubber.

The invention according to claim 10 is
A process cartridge comprising at least the charging member according to any one of claims 1 to 8.

The invention according to claim 11 is
An image forming apparatus comprising: a charging member according to any one of claims 1 to 8, comprising at least an image carrier, and charging means for contacting the image carrier and charging the surface thereof. It is an apparatus.

According to the invention of claim 1, the elastic layer contains a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer The proportion by mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is the same as or less than the proportion by mass, regardless of the environment over a long period regardless of the environment Provided is a charging member which is excellent in image quality maintenance.
According to the invention as set forth in claim 2, the charging member is provided which is more excellent in image quality maintenance over a long period regardless of the environment as compared with the case where the rubber material other than the epichlorohydrin rubber is ethylene-propylene-diene rubber (EPDM). .
According to the invention as set forth in claim 3, the rubber material other than the epichlorohydrin rubber is a long time regardless of the environment as compared with the case where the rubber material is at least one rubber selected from the group consisting of styrene butadiene rubber and chloroprene rubber. There is provided a charging member which is more excellent in image quality maintenance.
According to the invention as set forth in claim 4, compared to the case where the acrylonitrile content of the acrylonitrile butadiene rubber exceeds 25% by mass, a charging member is provided which is more excellent in image quality maintenance over a long period regardless of the environment.
According to the invention of claim 5, the content of the conductive carbon in the elastic layer is less than 5 parts by mass or 100 parts by mass with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber. A charging member is provided which is more excellent in image quality maintenance over a long time regardless of the environment, as compared to the case where the recording medium is oversized.
According to the invention of claim 6, the content of the conductive carbon in the elastic layer is less than 10 parts by mass or 50 parts by mass with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber. A charging member is provided which is more excellent in image quality maintenance over a long time regardless of the environment, as compared to the case where the recording medium is oversized.
According to the invention as set forth in claim 7 or 8, compared to the case where the elastic layer contains only rubber materials other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, the image quality can be maintained over a long period regardless of the environment. A charging member is provided.

According to the invention of claim 9, the elastic layer contains rubber materials other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer The proportion by mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is the same as or less than the proportion by mass, regardless of the environment over a long period regardless of the environment Provided is a method of manufacturing a charging member which is excellent in image quality maintenance.
According to the invention as set forth in claim 10, the elastic layer in the charging member contains a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the conductive material exists in the epichlorohydrin rubber per unit volume of the elastic layer. The proportion by mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is the same as or less than the proportion by mass of the functional carbon, depending on the environment A process cartridge excellent in image quality maintenance over a long period of time is provided.
According to the invention as set forth in claim 11, the elastic layer in the charging member contains a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the above-mentioned electric conduction present in the epichlorohydrin rubber per unit volume of the elastic layer The proportion by mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is the same as or less than the proportion by mass of the functional carbon, depending on the environment Thus, an image forming apparatus excellent in image quality maintenance over a long period of time is provided.

It is a schematic sectional drawing of the orthogonal | vertical direction to the axis | shaft of a roll which shows an example of the charging member which concerns on this embodiment. It is a schematic sectional drawing of the orthogonal | vertical direction to the axis | shaft of a roll which shows the other example of the charging member which concerns on this embodiment. FIG. 1 is a schematic view showing a basic configuration of an image forming apparatus according to a first embodiment. FIG. 7 is a schematic view showing a basic configuration of an image forming apparatus according to a second embodiment. It is a schematic diagram showing basic composition of an image forming device concerning a 3rd embodiment. It is a schematic diagram showing an example of a process cartridge concerning this embodiment.

Hereinafter, an embodiment which is an example of the present invention will be described in detail.
In the present specification, conductivity means that the volume resistivity at 20 ° C. is 1 × 10 ¹⁴ Ωcm or less.

[Charging member]
The charging member according to this embodiment has a conductive support and at least an elastic layer on the conductive support, and the elastic layer includes a conductive carbon, epichlorohydrin rubber, and a rubber material other than epichlorohydrin rubber. The mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer than the mass ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer It is a charging member having a large ratio.

The charging member is required to charge the photosensitive member in a nearly uniform state. For this reason, it is required to suppress the variation in the electrical resistance of the charging roll to be in a nearly uniform state.
Until now, various methods have been used as a means to make the electrical resistance uniform, but in recent years a uniform epichlorohydrin rubber material having a low resistance of the rubber material itself has been widely used.
However, epichlorohydrin rubber has a large environmental fluctuation of resistance, high resistance at low temperature and low humidity, and low resistance at high temperature and high humidity. When there is a resistance variation of the layer in which rubber is used, the voltage dependency applied to the other layers is observed, so that the environmental dependency of the chargeability occurs. In particular, at the time of direct current charging where only direct current is applied, the above-mentioned phenomenon becomes remarkable.
In addition, it is possible to suppress environmental fluctuation of resistance by making the conduction mechanism not of ion conduction type but of electronic conduction type, but since it is difficult to control resistance uniformity, charging becomes uneven and it is easy to generate white spots etc. .
Furthermore, although an electroconductive rubber is mixed with epichlorohydrin rubber to suppress environmental fluctuation of resistance, the resistance of the epichlorohydrin rubber portion is low, so that electricity flows more easily than the electron conductive region. Therefore, the load by energization is large and the resistance is easily increased.

On the other hand, in the charging member according to this embodiment, the elastic layer contains a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the conductive material exists in the epichlorohydrin rubber per unit volume of the elastic layer. The mass fraction of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is higher than the mass fraction of the penetrable carbon, so that the image quality maintaining property is excellent over a long period regardless of the environment. . Although the reason is not clear, it is guessed as follows.
As described above, epichlorohydrin rubber is a material having excellent conductivity, but the environmental change of resistance is large, the resistance is high at low temperature and low humidity, the resistance is low at high temperature and high humidity, and the environmental stability is poor.
In addition, rubber materials other than epichlorohydrin rubber, which are often used for elastic layers, are materials having poor conductivity, and when conductive carbon is dispersed in the same proportion in the portion of epichlorohydrin rubber and the portion of rubber material other than epichlorohydrin rubber, epichlorohydrin Since a large amount of current flows in the rubber portion and control of resistance uniformity is difficult, it is considered that charging becomes uneven and white spots and the like are easily generated.
Therefore, the presence of more conductive carbon in rubber materials other than epichlorohydrin rubber in the elastic layer improves resistance uniformity, excellent in charging uniformity, and image quality over a long period regardless of the environment, as compared to in epichlorohydrin rubber. It is estimated that a charging member having excellent maintainability can be obtained.

  Hereinafter, the configuration of the charging member according to the present embodiment will be described in detail.

The layer configuration of the charging member according to the present embodiment is not particularly limited as long as it has a conductive support and at least an elastic layer formed on the conductive support. There may be one or more adhesive layers between the layers, a surface layer, and one or more intermediate layers between the elastic layer and the surface layer (see FIGS. 1 and 2). In addition, a conductive agent may be blended in the constituent material in order to obtain desired resistance in each layer.
The form of the charging member is not particularly limited, as exemplified by a roll, a sheet, a blade, etc. Among them, at least the surface layer on the outer peripheral surface of a cylindrical or cylindrical conductive support Preferably, a roll-shaped charging roll is provided.
Hereinafter, the configuration of the charging roller, which is an embodiment of the charging member, will be described by way of example.

FIG. 1 is a schematic cross-sectional view in the direction perpendicular to the axis of a roll, showing an example of a charging member (charging roll) according to the present embodiment. The charging roll shown in FIG. 1 includes an adhesive layer 32, an elastic layer 33 and a surface layer 35 on a conductive support 31.
FIG. 2 is a schematic cross-sectional view in the direction perpendicular to the axis of the roll, showing another example of the charging member (charging roll) according to the present embodiment. The charging roll shown in FIG. 2 includes, on a conductive support 31, an adhesive layer 32, an elastic layer 33, an intermediate layer 34, and a surface layer 35.
The configuration of the charging roll according to the present embodiment is not limited to this, and any other configuration may be used as long as the conductive support and the surface layer having the above-described configuration are provided. For example, the adhesive layer 32 shown in FIGS. 1 and 2 may not be provided.

  The configuration of the charging roll shown in FIG. 1 will be mainly described below. In the following description, reference numerals may be omitted.

(Conductive support)
The charging member according to the present embodiment has a conductive support.
The conductive support functions as an electrode and support member of the charging roll, and is a metal or alloy such as aluminum, copper alloy, stainless steel, etc .; iron plated with chromium, nickel etc., for example, as shown in JIS G4804 What is comprised with the material which plated with chromium, nickel etc. to the free-cutting steel currently used is used. The plating may be formed by electrolytic plating, electroless plating, or the like, and is not limited.

(Adhesive layer)
The charging member according to this embodiment may have an adhesive layer, and for example, it is preferable to have one or more adhesive layers between the conductive support and the elastic layer.
The material for forming the adhesive layer is not particularly limited, but, for example, polyolefin type, chlorine rubber type, acrylic type, epoxy type, polyurethane type, nitrile rubber type, vinyl chloride type, vinyl chloride type, vinyl acetate type, polyester type, phenol type, silicone type And the like, and from the viewpoint of adhesion to the rubber and elastomer forming the elastic layer, polyolefin-based and phenol-based materials are particularly preferable.

The adhesive layer may have a single layer structure or a combination of plural layers.
In the adhesive layer, carbon blacks such as ketjen black and acetylene black provided with conductivity; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel and stainless steel; tin oxide, indium oxide, titanium oxide Various conductive metal oxides such as tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution; conductive surfaces of insulating materials; even powders such as powders, liquid rubber etc. Good.

  The thickness of the adhesive layer is not particularly limited, but is preferably, for example, 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

(Elastic layer)
The charging member according to the present embodiment has at least an elastic layer on the conductive support.
The elastic layer may or may not be in direct contact with the conductive support. For example, the adhesive layer may be provided between the conductive support and the elastic layer.
The elastic layer is a member having a function of imparting elasticity to the charging member according to the present embodiment, and by providing the elastic layer, a nip with the member to be charged is favorably formed.

The elastic layer in the charging member according to the present embodiment includes rubber materials other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber, and the mass ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer The mass ratio of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer is more than that.
In the present embodiment, “conductive carbon present in epichlorohydrin rubber” refers to conductive carbon in a state of being surrounded by epichlorohydrin rubber when the cross section in the thickness direction of the elastic layer is observed. "Conductive carbon present in a rubber material other than epichlorohydrin rubber" means that the conductive carbon is surrounded by a rubber material other than epichlorohydrin rubber when the cross section in the thickness direction of the elastic layer is observed. Sex carbon.
The elastic layer in the present embodiment is a layer in which the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber form at least one structure selected from the group consisting of a sea-island structure and an interpenetrating network structure. Is preferred.
Further, the mass ratio ^{CE of the} conductive carbon per unit volume present in the epichlorohydrin rubber in the elastic layer, and the mass ratio per unit volume of the conductive carbon present in a rubber material other than the epichlorohydrin rubber In the case of C 2 ^O , the ratio C 2 ^{O 2} / C 2 ^E , which is the ratio, is preferably 1.2 or more and 50 or less, and 2 or more and 30 or less from the viewpoint of image quality maintenance over a long period regardless of the environment. Is more preferable, and is particularly preferably 5 or more and 20 or less.

  The ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer, and the ratio of the conductive carbon present in a rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer The method to confirm is converting the area ratio of carbon by a transmission electron microscope (TEM) into a mass ratio. The epichlorohydrin rubber is determined from the presence or absence of a chlorine atom, infrared absorption spectroscopy (IR) analysis and nuclear magnetic resonance (NMR) analysis.

In the elastic layer, the amount of conductive carbon present in the epichlorohydrin rubber is 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the epichlorohydrin rubber from the viewpoint of image quality maintenance over a long period regardless of the environment. It is preferable that it is 0.5 to 20 mass parts, It is especially preferable that it is 1 to 10 mass parts.
In the elastic layer, the amount of conductive carbon present in the rubber material other than epichlorohydrin rubber is 10 mass with respect to 100 parts by mass of the rubber material other than epichlorohydrin rubber from the viewpoint of image quality maintenance over a long period regardless of the environment The content is preferably in the range of 100 parts by weight to 100 parts by weight, more preferably in the range of 20 parts by weight to 80 parts by weight, and particularly preferably in the range of 40 parts by weight to 60 parts by weight.

-Rubber material-
The elastic layer in the charging member according to the present embodiment includes epichlorohydrin rubber and a rubber material other than epichlorohydrin rubber.
The epichlorohydrin rubber is not particularly limited, but the epichlorohydrin rubber is a polymer rubber containing at least epichlorohydrin as a polymerization component. The epichlorohydrin-based rubber may be any of epichlorohydrin homopolymers and multicomponent copolymers (such as binary copolymers and ternary copolymers).
As epichlorohydrin rubber, for example, epichlorohydrin homopolymer, epichlorohydrin-allyl glycidyl ether copolymer, epichlorohydrin-alkylene oxide (ethylene oxide, propylene oxide, or both) copolymer, epichlorohydrin-alkylene oxide-allyl glycidyl ether copolymer And a combination thereof, allyl glycidyl ether modified epichlorohydrin-alkylene oxide copolymer and the like.
Among them, at least one selected from the group consisting of an epichlorohydrin-ethylene oxide copolymer and an epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer from the viewpoint of image quality maintenance over a long period regardless of environment and resistance uniformity. Epichlorohydrin rubber is particularly preferred.

As rubber materials other than epichlorohydrin rubber, isoprene rubber, chloroprene rubber, butyl rubber, polyurethane, silicone rubber, fluororubber, styrene-butadiene rubber, butadiene rubber, ethylene propylene rubber, ethylene-propylene-diene terpolymer rubber (EPDM) And acrylonitrile-butadiene rubber (NBR, nitrile rubber), natural rubber and the like.
The rubber material other than epichlorohydrin rubber is preferably a rubber material incompatible with epichlorohydrin rubber.
Rubber materials other than epichlorohydrin rubber may be used singly or in combination of two or more.

Among them, rubber materials other than epichlorohydrin rubber are at least one rubber selected from the group consisting of acrylonitrile butadiene rubber, styrene butadiene rubber, and chloroprene rubber from the viewpoint of image quality maintenance over a long period regardless of the environment. It is preferable, and at least one rubber selected from the group consisting of acrylonitrile butadiene rubber and styrene butadiene rubber is more preferable, and acrylonitrile butadiene rubber is particularly preferable.
When the content W ^E of epichlorohydrin rubber in the elastic layer and the content W ^O of rubber materials other than the above epichlorohydrin rubber are used, the value of W ^O / W ^E which is the ratio is a long-term image quality regardless of the environment. From the viewpoint of maintenance, it is preferably 0.20 or more and 4 or less, more preferably 0.25 or more and 3 or less, still more preferably 0.50 or more and 2 or less, and 0.80 or more. Particularly preferred is 25 or less.

  In addition, the amount of acrylonitrile (content of monomer units derived from acrylonitrile) of acrylonitrile butadiene rubber is preferably 30% by mass or less, and 25% by mass or less from the viewpoint of image quality maintenance over a long period regardless of the environment. Is more preferable, 20% by mass or less is more preferable, and 16% by mass or more and 19% by mass or less is particularly preferable.

-Conductive agent-
The elastic layer in the charging member according to the present embodiment contains conductive carbon as a conductive agent.
In addition, a conductive agent other than conductive carbon may be added to the elastic layer.
Examples of the conductive carbon include carbon black such as ketjen black and acetylene black, pyrolytic carbon, graphite and the like.
Among these, carbon black is preferably mentioned as the conductive carbon.
Further, the conductive carbon present in the epichlorohydrin rubber and the conductive carbon present in a rubber material other than the epichlorohydrin rubber may be the same as or different from each other, and Each may be one kind alone, or two or more kinds may be mixed.
The arithmetic average particle diameter of the conductive carbon is preferably 10 nm or more and 200 nm or less, more preferably 10 nm or more and 100 nm or less, and particularly preferably 30 nm or more and 70 nm or less.
The method of measuring the arithmetic mean particle diameter of the conductive carbon in the present embodiment is to measure the particle size distribution using a laser diffraction type particle size distribution measuring apparatus (for example, LS13 320 manufactured by Beckman Coulter, Inc.), and each peak of the particle size distribution. Calculate the number average particle size for. Arithmetic mean particle size is calculated by subtracting the cumulative distribution of the number of particles from the small particle size side of each peak with respect to the divided particle size range (channel), and making the cumulative particle size 50% of all particles of each peak. , Arithmetic mean particle diameter of corresponding particles.

As a conductive agent other than conductive carbon, an electronic conductive agent other than conductive carbon and an ion conductive agent are used.
Examples of electronic conductive agents other than conductive carbon include various conductive metals or alloys such as aluminum, copper, nickel and stainless steel; tin oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, tin oxide-oxide Examples thereof include powders of various conductive metal oxides such as indium solid solution; those obtained by subjecting the surface of an insulating material to a conductive treatment; and the like.

  Examples of the ion conductive agent include quaternary ammonium salts such as tetraethyl ammonium and lauryl trimethyl ammonium; alkali metals such as lithium and magnesium; perchlorates of alkaline earth metals; chlorates; and the like.

Among them, as an ion conductive agent, quaternary ammonium salt compounds, alkali metal or alkaline earth metal salts of perchloric acid, and alkali metals or alkalis of chloric acid from the viewpoint of image quality maintenance over a long period regardless of the environment It is preferably at least one compound selected from the group consisting of earth metal salts, and more preferably quaternary ammonium salt compounds.
Moreover, as a conductive agent, it is preferable to use a conductive carbon and an ion conductive agent in combination from the viewpoint of image quality maintenance over a long period regardless of the environment.

The conductive agents may be used alone or in combination of two or more.
Although the addition amount of the conductive agent is not particularly limited, in the case of the electron conductive agent (conductive carbon and other electronic conductive agents), 1 part by mass or more and 30 parts by mass with respect to 100 parts by mass of the rubber component. The content is preferably in the range of parts by mass or less and more preferably in the range of 5 parts by mass or more and 25 parts by mass or less.
On the other hand, in the case of the above-mentioned ion conductive agent, it is preferable that it is a range of 0.1 mass part or more and 5.0 mass parts or less with respect to 100 mass parts of rubber components. The following range is more preferable.

  The content of the conductive carbon in the elastic layer is 5 parts by mass or more to 100 parts by mass with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber from the viewpoint of image quality maintenance over a long time regardless of the environment. It is preferable that it is the following, It is more preferable that it is 7 to 80 mass parts, It is especially preferable that it is 10 to 50 mass parts.

-Crosslinking agent-
When the rubber component is crosslinked, materials such as a crosslinking agent and a crosslinking accelerator are further used. Generally, types of crosslinking by a crosslinking agent include sulfur crosslinking, peroxide crosslinking, quinoid crosslinking, phenolic resin crosslinking, amine crosslinking, metal oxide crosslinking and the like, but crosslinking with a material having a double bond From the viewpoint of ease of application and flexibility of the crosslinked rubber, crosslinking by sulfur is preferred. Even in the case of sulfur crosslinking, crosslinking using a crosslinking agent which releases activated sulfur from the compound instead of a single sulfur is preferable because the distance between bonds can be shortened, and 4,4′-dithiodimorpholine is preferable.

  Examples of the crosslinking accelerator include thiazoles, thiurams, sulfenamides, thioureas, dithiocarbamates, guanidines, aldehydes-ammonias, and mixtures thereof.

-Other additives-
The rubber composition forming the elastic layer may be blended with other additives as required. As other additives, fillers, crosslinking accelerating assistants and the like can be mentioned.
Other fillers include silica, calcium carbonate, clay and the like.
Examples of the vulcanization acceleration assistant include zinc oxide and the like.

  The addition amount of the other additives is preferably in the range of 10 parts by mass to 100 parts by mass with respect to 100 parts by mass of the rubber component, including particles such as zinc oxide as a vulcanization acceleration aid. The range of 20 parts by mass to 80 parts by mass is more preferable.

  When the resistance layer is formed, the above-mentioned constituent material (rubber composition) of the elastic layer may be used as a constituent material of the resistance layer.

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 volume resistivity of the elastic layer is preferably 10 ³ Ωcm or more and 10 ¹⁴ Ωcm or less.

The volume resistivity is a value measured by the following method.
A sheet-like measurement sample is collected from the object to be measured, and a measurement jig (R12702A / B resistivity chamber: made by ADVANTEST CORPORATION) and a high-resistance measuring device (R8340A) according to JIS K 6911 (1995). After applying a voltage adjusted so that the electric field (applied voltage / composition sheet thickness) becomes 1000 V / cm for 30 seconds using a digital high-resistance / micro-ammeter: manufactured by ADVANTEST CORPORATION, the following flowing current value Calculate using the equation.
Volume resistivity (Ω cm) = (19.63 × applied voltage (V)) / (current value (A) × measurement sample thickness (cm))

-Formation of elastic layer-
An elastic layer knead | mixes the mixture of each component mentioned above, for example, prepares the composition for elastic layer formation, and it uses the extrusion molding machine, the injection molding machine, the press molding machine etc. in which the crosshead was equipped. The composition is extruded and vulcanized onto the conductive support.

(Surface layer)
The charging member according to the present embodiment may have a surface layer on the elastic layer.
The surface layer preferably contains a binder resin, a metal oxide, and carbon black. In addition, particles for adjusting the surface roughness of the surface layer (hereinafter also referred to as “filler”), other additives, and the like may be included.

As a binder resin (polymer material), for example, acrylic resin, fluorine modified acrylic resin, silicone modified acrylic resin, cellulose resin, polyamide resin, copolymer nylon, polyurethane resin, polycarbonate resin, polyester resin, polyimide resin, epoxy resin Silicone resin, polyvinyl alcohol resin, polyvinyl butyral resin, cellulose resin, polyvinyl acetal resin, ethylene tetrafluoroethylene resin, melamine resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin. Polyethylene terephthalate resin (PET), fluorocarbon resin (polyvinylidene fluoride resin, tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc. Can be mentioned. Further, the binder resin may also be one obtained by curing or crosslinking a curable resin with a curing agent or a catalyst. The binder resin may be an elastic material.
The binder resin may be used alone, or two or more types may be mixed or copolymerized. In the case of a crosslinkable resin, it may be used after crosslinking.
Here, the copolymerized nylon is a copolymer including any one or more of 610 nylon, 11 nylon, and 12 nylon as a polymerization unit. The copolymerized nylon may contain other polymerized units such as 6 nylon and 66 nylon.

  Among these, polyvinylidene fluoride resin, tetrafluoroethylene resin, and polyamide resin are preferable as the resin from the viewpoint of suppressing the contamination of the surface layer and easily suppressing the occurrence of the charging unevenness, and the polyamide resin is more preferable. The polyamide resin is unlikely to cause frictional charging due to contact with a member to be charged (for example, an image carrier), and adhesion of toner and external additive is easily suppressed.

  As a polyamide resin, the polyamide resin described in the polyamide resin handbook (Fukumoto Osamu, Nikkan Kogyo Shimbun Co., Ltd.) is mentioned. Among these, as the polyamide resin, alcohol-soluble polyamide is preferable, and alkoxymethylated polyamide (alkoxymethylated nylon) is more preferable, and methoxymethylated polyamide (in particular, from the viewpoint of suppressing contamination of the surface layer and suppressing charging unevenness). More preferred is methoxymethylated nylon).

  The number average molecular weight of the binder resin (polymer material) is preferably in the range of 1,000 to 100,000, and more preferably in the range of 10,000 to 50,000.

The surface layer is preferably formed as a composition by mixing the binder resin with carbon black, a conductive agent and various fillers. Other additives such as dispersants and leveling agents are also added as needed.
The filler is added to control the electrical properties and to form convex portions of the surface roughness, and the addition amount thereof is not particularly limited, but in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the binder resin. Is preferably, and more preferably in the range of 3 to 20 parts by mass.
The fillers may be used alone or in combination of two or more.

  In addition, the surface layer may contain other additives, for example, known additives such as a curing agent, a vulcanizing agent, a vulcanization accelerator, an antioxidant, a dispersant, a surfactant, a coupling agent, etc. Agents.

  The thickness of the surface layer is preferably 1 μm or more and 20 μm or less, and more preferably 3 μm or more and 15 μm or less.

-Formation of surface layer-
The surface layer is formed by dispersing or dissolving the above components in a solvent to prepare a coating solution, applying the coating solution on the elastic layer prepared in advance, and drying it. Examples of the method of applying the coating solution include blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method and the like.
The solvent used for the coating solution is not particularly limited and general ones may be used. For example, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; diethyl ether, dioxane and the like Solvents such as ethers may be used.

(Intermediate layer)
The charging member according to the present embodiment may have an intermediate layer, and may have, for example, one or more intermediate layers between the elastic layer and the surface layer.
The intermediate layer is provided as needed for resistance adjustment when the electrical resistance of the elastic layer is low. The material constituting the intermediate layer is not particularly limited, but epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, butadiene rubber, acrylonitrile-butadiene copolymer rubber (NBR), natural And rubbers, and blends thereof.

[Method of manufacturing charging member]
The method for producing the charging member according to the present embodiment is not particularly limited, but after each of the step of dispersing conductive carbon in epichlorohydrin rubber and the step of dispersing conductive carbon in a rubber material other than epichlorohydrin rubber It is preferable that the method includes a step of mixing the epichlorohydrin rubber containing the conductive carbon and a rubber material other than the epichlorohydrin rubber containing the conductive carbon.

There is no restriction | limiting in particular as a method to disperse | distribute electroconductive carbon to rubber materials other than epichlorohydrin rubber or epichlorohydrin rubber, A well-known dispersion method can be used. Among them, a method of performing kneading (rubber kneading) using a kneader (rubber kneading) is preferably mentioned.
The amounts of conductive carbon used in the step of dispersing conductive carbon in epichlorohydrin rubber and in the step of dispersing conductive carbon in a rubber material other than epichlorohydrin rubber may be appropriately set according to the desired content ratio. However, the amount of conductive carbon used in the step of dispersing conductive carbon in a rubber material other than epichlorohydrin rubber is larger than the amount of conductive carbon used in the step of dispersing conductive carbon in epichlorohydrin rubber.

Epichlorohydrin rubber containing the conductive carbon obtained by the step of dispersing conductive carbon in epichlorohydrin rubber and rubber other than epichlorohydrin rubber containing the conductive carbon by the step of dispersing conductive carbon in a rubber material other than epichlorohydrin rubber There is no restriction | limiting in particular as a mixing method in the process of mixing a material, A well-known mixing method can be used. Among them, a mixing method using an open roll is preferably mentioned.
Moreover, the temperature and time in the said dispersion | distribution and mixing do not have a restriction | limiting in particular, What is necessary is just to set each suitably.

An elastic layer is formed on a conductive support using a material obtained by the step of mixing the epichlorohydrin rubber containing the conductive carbon and a rubber material other than the epichlorohydrin rubber containing the conductive carbon, and a charging member is obtained. It is preferable to form.
The method for forming the elastic layer is not particularly limited, and a known method may be used. For example, a method of forming by injection molding is preferably mentioned. Conditions such as injection temperature in injection molding may be set appropriately.

[Charging device]
The charging device according to the present embodiment is a charging device provided with the charging member according to the present embodiment.
The charging device according to the present embodiment may be constituted only by, for example, the charging member according to the present embodiment, or the charging member according to the present embodiment and the cleaning member are disposed in contact with each other at a specific bite amount. It may be a configuration.

  The charging device provided with the charging member according to the present embodiment is used for the purpose of charging the body to be charged while being in contact with the body to be charged. For example, it is suitably used as a charging member in an image forming apparatus, and specifically, the toner is transferred from the image holding member (electrophotographic photosensitive member) to the recording medium from the charging member for charging the image holding member (electrophotographic photosensitive member) It is used as a transfer member or the like.

[Image forming apparatus]
The image forming apparatus according to the present embodiment includes at least an image carrier, and a charging unit that contacts the image carrier and charges the surface thereof, and the image forming unit includes the charging member according to the present embodiment. A charging device including an image carrier, the charging member according to the present embodiment, and the charging member for charging the image carrier by bringing the charging member into contact with the surface of the image carrier; A latent image forming device for forming a latent image on the surface of the image carrier, a developing device for developing a latent image formed on the surface of the image carrier with toner to form a toner image, and It is preferable that the image forming apparatus includes a transfer device for transferring the toner image to a recording medium.
Hereinafter, an image forming apparatus according to the present embodiment will be described based on the drawings.

-1st Embodiment-
FIG. 3 is a schematic view showing a basic configuration of the image forming apparatus according to the first embodiment. The image forming apparatus 200 shown in FIG. 3 includes an electrophotographic photosensitive member (an example of an image carrier) 207, a charging device 208 for charging the electrophotographic photosensitive member 207, a power source 209 connected to the charging device 208, and a charging device. An exposure device (an example of a latent image forming device) 206 which exposes the electrophotographic photosensitive member 207 charged by 208 to form a latent image, and the latent image formed by the exposure device 206 is developed with toner to obtain a toner image The image forming apparatus includes a developing device 211 to be formed, a transfer device 212 for transferring a toner image formed by the developing device 211 to the recording medium 500, a cleaning device 213, a static eliminator 214, and a fixing device 215. The static eliminator 214 shown in FIG. 3 may not be provided.

  The electrophotographic photosensitive member 207 is not particularly limited, and a known electrophotographic photosensitive member is used. For example, on a conductive substrate, an undercoating layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge generation layer and the charge transport layer are separately provided. A photoreceptor is mentioned. In addition, it may be a photosensitive member having a function integral type photosensitive layer provided with both charge generation capability and charge transport capability. The electrophotographic photosensitive member 207 may not be provided with the undercoat layer, may be provided with an intermediate layer between the undercoat layer and the photosensitive layer, and is protected by including the charge transport material on the photosensitive layer. A layer may be provided.

  The electrophotographic photosensitive member 207 preferably has a total thickness of 25 μm or more, and 25 μm or more and 32 μm or less from the viewpoint of prolonging the life while suppressing the occurrence of image defects. Is more preferred.

  Here, in the present embodiment, the “surface layer having charge transportability” of the photosensitive member refers to the function separation type photosensitive layer, and in the case where the charge transport layer including the charge transport material is the outermost surface layer, the charge transport layer. In the case of having a protective layer containing a charge transport material on the charge transport layer, it is the total thickness of the charge transport layer and the protective layer, and the photosensitive layer of a function integrated type including the charge transport material is the outermost surface. When it is a layer, it is the photosensitive layer, and when it has a protective layer containing a charge transport material on the functional integrated photosensitive layer, it is the total thickness of the photosensitive layer and the protective layer.

  The charging device 208 is a system (contact charging system) of charging the surface of the photosensitive member 207 by bringing a charging member (charging roll) into contact with the surface of the electrophotographic photosensitive member 207, and relates to the above-described embodiment. A charging device provided with a charging member is used.

  As the exposure device 206, an optical system device capable of exposing a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like to a desired image on the surface of the electrophotographic photosensitive member can be used.

  The developing device 211 contains toner. The toner used in the present embodiment is configured to include, for example, a binder resin and a colorant. Examples of the binder resin include homopolymers and copolymers of styrenes, monoolefins, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, vinyl ethers, vinyl ketones, etc. Representative binding resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer And coal, polyethylene, polypropylene and the like. Further, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can also be mentioned.

  As colorants, magnetic powder such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chromium yellow, ultramarine blue, duPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black Rose Bengal C. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 etc. can be mentioned as a representative.

The toner may be subjected to internal addition processing or external addition processing of a known additive such as a charge control agent, a release agent, or other inorganic particles.
As a mold release agent, low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, candelilla wax etc. are mentioned as a typical thing.
As a charge control agent, although a well-known thing can be used, charge control agents, such as an azo metal complex compound, a metal complex compound of salicylic acid, and a resin type containing a polar group, can be used.

As other inorganic particles, small-diameter inorganic particles having an average primary particle diameter of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger in diameter for reducing adhesion. Inorganic or organic particles may be used in combination. Known other inorganic particles can be used.
In addition, the surface treatment of the small-diameter inorganic particles is effective because the dispersibility is enhanced and the effect of improving the powder flowability is increased.

  As a method for producing the toner used in the present embodiment, a polymerization method such as an emulsion polymerization aggregation method or a solution suspension method is preferably used because high shape controllability can be obtained. Alternatively, the toner obtained by the above-described method may be used as a core, and further aggregation particles may be attached and heat fused to give a core-shell structure. When an external additive is added, it can be produced by mixing the toner and the external additive with a Henschel mixer or a V blender. When the toner is produced by a wet process, it may be externally added by a wet process.

  When transferring the toner image formed on the electrophotographic photosensitive member 207 onto the recording medium 500, the transfer device 212 can supply a current of a predetermined current density toward the electrophotographic photosensitive member. Is preferred.

  The cleaning device 213 is for removing the residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this is repeatedly subjected to the above image forming process. . As the cleaning device, in addition to the cleaning blade, brush cleaning, roll cleaning and the like can be used, but among these, it is preferable to use the cleaning blade. Further, as a material of the cleaning blade, urethane rubber, neoprene rubber, silicone rubber and the like can be mentioned.

  Further, as shown in FIG. 3, the image forming apparatus according to the present embodiment may further include an erase light irradiation device 214 as a charge removing device for removing the residual potential of the electrophotographic photosensitive member. This prevents the phenomenon in which the residual potential of the electrophotographic photosensitive member is brought to the next cycle when the electrophotographic photosensitive member is repeatedly used, and therefore the image quality can be further improved.

-Second embodiment-
FIG. 4 is a schematic view showing the basic configuration of the image forming apparatus according to the second embodiment. The image forming apparatus 210 shown in FIG. 4 transfers the toner image formed on the electrophotographic photosensitive member 207 to the primary transfer member 212a, and then supplies the toner image between the primary transfer member 212a and the secondary transfer member 212b. An intermediate transfer type transfer device for transferring to the recording medium 500, and at the time of such transfer, a current of a predetermined current density can be supplied from the primary transfer member 212a to the electrophotographic photosensitive member. ing. Although not shown in FIG. 4, the image forming apparatus 210 may further include a static eliminator similar to the image forming apparatus 200 shown in FIG. 3. Further, the other configuration of the image forming apparatus 210 is the same as the configuration of the image forming apparatus 200.
As described above, the image forming apparatus 210 differs in that the intermediate transfer method is applied. However, as in the case of the image forming apparatus 200 according to the first embodiment, the electrophotographic photosensitive member 207 and the present embodiment are implemented. By combining with the charging device provided with the charging member according to the embodiment, the occurrence of the image defect is suppressed.

  Furthermore, when the toner image formed on the electrophotographic photosensitive member 207 is transferred to the primary transfer member 212a, a current of a predetermined current density is supplied from the primary transfer member 212a to the electrophotographic photosensitive member 207. This makes it possible to suppress the fluctuation of the transfer current due to the type, material, and the like of the recording medium 500, so that the amount of charge flowing into the electrophotographic photosensitive member 207 can be accurately controlled. As a result, it is possible to achieve higher image quality and reduced environmental impact at a higher level.

-Third embodiment-
FIG. 5 is a schematic view showing the basic configuration of the image forming apparatus according to the third embodiment. The image forming apparatus 220 shown in FIG. 5 is an intermediate transfer type image forming apparatus, and in the housing 400, four electrophotographic photosensitive members 401a to 401d (for example, the electrophotographic photosensitive member 401a is yellow and the electrophotographic photosensitive member 401b is magenta) The electrophotographic photosensitive member 401 c can form an image of cyan and the electrophotographic photosensitive member 401 d can form a black color, respectively, which are arranged in parallel along the intermediate transfer belt 409.

  Each of the electrophotographic photosensitive members 401a to 401d is rotatable in a specific direction (counterclockwise in the drawing), and charging members (charging rolls) 402a to 402d and developing devices 404a to 404d, 1 are arranged along the rotation direction. Next transfer rolls 410a to 410d and cleaning blades 415a to 415d are disposed. The four color toners of black, yellow, magenta, and cyan contained in the toner cartridges 405a to 405d can be supplied to the developing devices 404a to 404d, respectively. The primary transfer rolls 410 a to 410 d are in contact with the electrophotographic photosensitive members 401 a to 401 d via the intermediate transfer belt 409, respectively.

  Further, a laser light source (exposure device) 403 is disposed in the housing 400, and it becomes possible to irradiate the surface of the electrophotographic photosensitive members 401a to 401d after charging with the laser light emitted from the laser light source 403. ing. Thus, the steps of charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401 a to 401 d, and toner images of the respective colors are transferred overlappingly on the intermediate transfer belt 409.

  The intermediate transfer belt 409 is supported under tension by a drive roll 406, a back roll 408 and a tension roll 407, and can rotate without deflection by rotation of these rolls. Further, the secondary transfer roll 413 is arranged to be in contact with the back roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 which has passed between the back roll 408 and the secondary transfer roll 413 is cleaned, for example, by a cleaning blade 416 disposed in the vicinity of the drive roll 406, and then repeatedly subjected to the next image forming process. Be done.

  Further, a recording medium storage container 411 is provided in the housing 400, and the recording medium 500 such as paper in the recording medium storage container 411 is transferred between the intermediate transfer belt 409 and the secondary transfer roll 413 by the transfer roll 412, Furthermore, after being sequentially transferred between two fixing rolls 414 in contact with each other, the sheet is discharged to the outside of the housing 400.

  Although the case of using the intermediate transfer belt 409 as an intermediate transfer member has been described in the above description, the intermediate transfer member may be belt-like as the intermediate transfer belt 409 or may be drum-like. It may be.

Process cartridge
The process cartridge according to the present embodiment is a process cartridge provided with at least the charging member according to the present embodiment, and the charging member which contacts the surface of the image carrier and the surface of the body to be charged and charges the surface of the body Preferably, the process cartridge includes the charging device having the charging member according to the present embodiment, and is detachable from the image forming apparatus.

FIG. 6 is a schematic view showing an example of the process cartridge according to the present embodiment. The process cartridge 300 shown in FIG. 6 includes an electrophotographic photosensitive member (an example of an image carrier) 207, a charging device 208, a developing device 211, a cleaning device 213, an opening 217 for exposure, and an opening for discharge exposure. 218 are combined and integrated using mounting rails 216. The developing device 211 supplies toner to the electrophotographic photosensitive member 207.
The process cartridge 300 is detachably attachable to the image forming apparatus main body including the transfer device 212, the fixing device 215, and other components not shown, and the image forming apparatus as well as the image forming apparatus main body. Configure

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. In addition, "part" means a "mass part" unless there is particular notice.

Example 1
-Preparation of rubber composition-
A mixture of the following composition was kneaded (rubber kneading) with a kneader to obtain a rubber material 1.
· Matrix material A-1: 100 parts by mass (epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, Hydran T3108, manufactured by Nippon Zeon Co., Ltd.)
· Conductive material B-1: 1.5 parts by mass (benzyl trimethyl ammonium chloride, trade name "BTEAC", manufactured by Lion Akzo Co., Ltd.)
· Conductive material B-2: 5 parts by mass (carbon black, # 3030B, manufactured by Mitsubishi Chemical Corporation, arithmetic mean particle size: 55 nm)
Calcium carbonate: 30 parts by mass Stearic acid: 1 part by mass Zinc oxide: 5 parts by mass
(Zinc oxide 1 type, manufactured by Shodo Chemical Industry Co., Ltd.)
Vulcanizing agent: 2 parts by mass (organic sulfur, 4,4'-dithiodimorpholine, Barnock R, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Vulcanization accelerator: 1.5 parts by mass (thiazole, di-2-benzothiazolyl disulfide, Noxceler DM-P, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Vulcanization accelerator: 1.5 parts by mass (thiuram, tetraethylthiuram disulfide, Noxceler TET-G, manufactured by Ouchi Shinko Chemical Co., Ltd.)

A mixture of the following composition was kneaded (rubber kneading) with a kneader to obtain a rubber material 2.
· Matrix material A-2: 100 parts by mass (acrylonitrile butadiene rubber, N250S, 19.5% by mass of acrylonitrile, manufactured by JSR Corporation)
· Conductive material B-1: 1.5 parts by mass (benzyl trimethyl ammonium chloride, trade name "BTEAC", manufactured by Lion Akzo Co., Ltd.)
· Conductive material B-2: 50 parts by mass (carbon black, # 3030B, manufactured by Mitsubishi Chemical Corporation)
Calcium carbonate: 30 parts by mass Stearic acid: 1 part by mass Zinc oxide: 5 parts by mass
(Zinc oxide 1 type, manufactured by Shodo Chemical Industry Co., Ltd.)
Vulcanizing agent: 2 parts by mass (organic sulfur, 4,4'-dithiodimorpholine, Barnock R, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Vulcanization accelerator: 1.5 parts by mass (thiazole, di-2-benzothiazolyl disulfide, Noxceler DM-P, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Vulcanization accelerator: 1.5 parts by mass (thiuram, tetraethylthiuram disulfide, Noxceler TET-G, manufactured by Ouchi Shinko Chemical Co., Ltd.)

  The rubber material 1 and the rubber material 2 were mixed by an open roll to obtain a rubber composition 1.

-Preparation of elastic roll-
The rubber composition 1 was mixed with 2 parts by mass of carbon black (Ketjen Black EC 300J: manufactured by Lion Corporation): a polyolefin adhesive (XJ-150, manufactured by Lord Far East Co., Ltd.) and having a thickness of 15 μm An elastic layer was formed on a conductive support (SUM 24L) with a diameter of 8 mm on which an adhesive layer was formed using an injection molding machine, and vulcanized, and thereafter, the elastic roll 1 with a diameter of 12 mm was obtained by polishing.

-Formation of surface layer-
The following mixture is dispersed by a bead mill, and the obtained dispersion liquid 1 is diluted with methanol, dip coated on the surface of the elastic elastic roll 1, heat dried at 160 ° C. for 30 minutes, and a 6 μm thick surface layer The charging member (charging roller) of Example 1 was obtained.

Polymer material (N-methoxymethylated nylon, F30K, manufactured by Nagase ChemteX Co., Ltd.): 100 parts by mass Polymer material (polyvinyl butyral resin, S-Lec BL-1, manufactured by Sekisui Chemical Co., Ltd.): 10 Mass part Metal oxide (tin oxide, 6010, manufactured by Mitsui Mining & Smelting Co., Ltd.): 60 parts by mass Carbon black (Ketjen black EC300J: manufactured by Lion Co.): 3 parts by mass Filler (polyamide resin, Orgasol 2001 DNat 1 Alkema Co., Ltd .: 10 parts by mass Catalyst (Nacure 4167: Enomoto Kasei Co., Ltd.) 1 part by mass Solvent (methanol) 700 parts by mass Solvent (butanol) 200 parts by mass

-Image quality maintenance evaluation-
The obtained charging member was mounted on a drum cartridge of a color copying machine DocuCentre-IV C2260 (manufactured by Fuji Xerox Co., Ltd.), and image quality was evaluated by halftone printing.
In the evaluation of high temperature and high humidity conditions, the color copying machine was installed in an atmosphere of 28 ° C. and 85% RH, and image quality evaluation after initial printing and after printing of 50,000 sheets was performed.
In addition, in the evaluation of low temperature and low humidity conditions, the color copying machine was installed in an atmosphere of 10 ° C. and 15% RH, and image quality evaluation after initial printing and after printing 50,000 sheets was performed.
The results are shown in Table 1 or Table 2.
A: No image defects such as uneven density, white spots, color spots, streaks and the like have not occurred.
B: Partial image defects such as slight density unevenness, white spots, color spots, and streaks.
C: Minor density unevenness, image defects such as white spots, color spots, streaks, etc. occur.
D: Image defects such as density unevenness, white spots, color spots, streaks, etc. occur.

-Measurement of volume resistivity of elastic layer-
The volume resistivity of the elastic layer was measured by the method described above, and the common logarithm of the obtained value was taken.
The results are shown in Table 1 or Table 2.

Examples 2 and 3 and Comparative Example 1
A charging member was produced and evaluated in the same manner as in Example 1 except that various matrix materials, conductive materials, and their contents were changed as described in Table 1 or Table 2.
Moreover, in the comparative example 1, all the materials of the said rubber material 1 and the said rubber material 2 were collectively knead | mixed (rubber kneading | mixing) by the kneader.

Examples 4 and 5
A charging member was produced and evaluated in the same manner as in Example 1 except that the content of carbon black in Example 2 was changed as described in Table 1.

Example 6
A charging member was produced and evaluated in the same manner as in Example 1 except that the epichlorohydrin rubber of the matrix material A-1 was changed to the following resin.
Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber: Hydran T3106, manufactured by Nippon Zeon Co., Ltd.

Example 7
A charging member was produced and evaluated in the same manner as in Example 1 except that acrylonitrile butadiene rubber of matrix material A-2 was changed to the following resin.
Styrene butadiene rubber: SL 552, manufactured by JSR Corporation

Example 8
A charging member was produced and evaluated in the same manner as in Example 1 except that the carbon black of the conductive material B-1 was changed to the following.
Carbon black: # 3050B, manufactured by Mitsubishi Chemical Corporation

Example 9
A charging member was produced and evaluated in the same manner as in Example 1 except that acrylonitrile butadiene rubber of matrix material A-2 was changed to the following resin.
Acrylonitrile butadiene rubber: N 222 L (Acrylonitrile content: 43%), manufactured by JSR Corporation

Comparative Example 2
A charging member was produced and evaluated in the same manner as in Example 1 except that the content of carbon black in Example 1 was changed as described in Table 2.

  In Comparative Example 1, the matrix materials A-1 and A-2 are sufficiently dispersed, and the conductive carbon in the elastic layer is composed of a mixture of epichlorohydrin rubber and a rubber material other than epichlorohydrin rubber. It was in contact with

  From the above results, it can be seen that the charging member of this example is superior to the charging member of the comparative example in image quality maintenance over a long period regardless of the environment.

  31: conductive support, 32: adhesive layer, 33: elastic layer, 34: intermediate layer, 35: surface layer, 200, 210, 220: image forming apparatus, 206: exposure device, 207: electrophotographic photosensitive member, 208 ... charging device 209 power source 211 developing device 212 transfer device 213 cleaning device 214 static elimination device 215 fixing device 216 mounting rail 217 aperture for exposure, 218 static elimination Opening for exposure 300 300 Process cartridge 400 Housing 401a to 401d Electrophotographic photosensitive member 402a to 402d Charging member (charging roll) 403 Laser light source (exposure device) 404a to 404d Development Apparatus, 405a to 405d: Toner cartridge, 406: Drive roll, 407: Stretching roll, 408: Back side row , 409: intermediate transfer belt, 410a to 410d: primary transfer roll, 411: recording medium storage container, 412: transfer roll, 413: secondary transfer roll, 414: fixing roll, 415a to 415d, cleaning blade, 416: cleaning Blade, 500 ... recording medium

Claims (11)

A conductive support,
At least an elastic layer on the conductive support,
The elastic layer comprises a rubber material other than conductive carbon, epichlorohydrin rubber and epichlorohydrin rubber,
The mass of the conductive carbon present in the rubber material other than the epichlorohydrin rubber per unit volume of the elastic layer than the mass ratio of the conductive carbon present in the epichlorohydrin rubber per unit volume of the elastic layer Charged member with a large percentage.   The charging member according to claim 1, wherein the rubber material other than the epichlorohydrin rubber is at least one rubber selected from the group consisting of acrylonitrile butadiene rubber, styrene butadiene rubber, and chloroprene rubber.   The charging member according to claim 2, wherein the rubber material other than the epichlorohydrin rubber is acrylonitrile butadiene rubber.   The charging member according to claim 3, wherein an acrylonitrile content of the acrylonitrile butadiene rubber is 25% by mass or less.   The content of the conductive carbon in the elastic layer is 5 parts by mass to 100 parts by mass with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber The charging member according to any one of the above.   The charging according to claim 5, wherein the content of the conductive carbon in the elastic layer is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total content of the epichlorohydrin rubber and the rubber material other than the epichlorohydrin rubber. Element.   The charging member according to any one of claims 1 to 6, wherein the elastic layer further contains an ion conductive agent.   At least one selected from the group consisting of quaternary ammonium salt compounds, alkali metal or alkaline earth metal salts of perchloric acid, and alkali metal or alkaline earth metal salts of chloric acid The charging member according to claim 7 which is a compound. Dispersing conductive carbon in epichlorohydrin rubber,
And d) dispersing conductive carbon in a rubber material other than epichlorohydrin rubber.
The method for manufacturing a charging member according to any one of claims 1 to 8, further comprising the step of mixing the epichlorohydrin rubber containing the conductive carbon and a rubber material other than the epichlorohydrin rubber containing the conductive carbon.   A process cartridge comprising at least the charging member according to any one of claims 1 to 8.   An image forming apparatus comprising: a charging member according to any one of claims 1 to 8, comprising at least an image carrier, and charging means for contacting the image carrier and charging the surface thereof. apparatus.