JP2016184149A - Charging member, charging device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging member that has suppressed occurrence of unevenness in charging.SOLUTION: There is provided a charging member that comprises a conductive support 31 and a surface layer 35 arranged on the conductive support 31, and has an electron emission energy on the surface of 10cps/eV or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charging member, a charging device, a process cartridge, and an image forming apparatus.

In an image forming apparatus using an electrophotographic method, an image holding member (electrophotographic photosensitive member) is charged by a charging device or the like to form a charge, and after forming an electrostatic latent image by a laser or the like that modulates an image signal, The electrostatic latent image is developed with charged toner to form a toner image. Then, the required image is obtained by transferring the toner image to a recording medium via an intermediate transfer member.
In this image forming apparatus, a non-contact charging device such as a corotron or a scorotron that is charged by a 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 contact-type charging device using a charging roll has been widely used because, for example, the applied voltage is small and the amount of ozone generated is small.

  Patent Document 1 discloses a charging member having a conductive substrate and a conductive surface layer, the surface layer including a binder resin and composite particles dispersed in the binder resin, The surface of the member has convex portions derived from the composite particles, the composite particles have an average particle diameter of 1 μm or more and 30 μm or less, and the core portion is coated with a conductive material, The core portion includes a polymer including units derived from ethylene oxide, and the content of the units derived from ethylene oxide is 20% by mass or more and 100% by mass or less with respect to the polymer. A charging member including at least one selected from the group consisting of carbon black, conductive polymer, metal oxide, and metal is disclosed.

  Patent Document 2 discloses a charging member having a surface layer on a conductive support, and the surface layer includes a binder resin, graphite particles, and a group consisting of calcium titanate, barium titanate, and strontium titanate. The surface of the charging member includes ferroelectric particles selected from the above, and convex portions derived from graphite particles (graphite convex portions) and convex portions derived from ferroelectric particles (ferroelectric convex portions) are formed. A charging member having a ferroelectric convexity lower than the plane of 80% or more of the total ferroelectric convexity when a plane including three vertices of the graphite convexity adjacent to the ferroelectric convexity is formed. Is disclosed.

Further, Patent Document 3 includes a shaft body, a resistance adjustment layer formed directly or via another layer on the outer periphery of the shaft body, and a protective layer formed on the outer periphery of the resistance adjustment layer. A charging roll, wherein the protective layer is composed of a composition containing the following (A) binder polymer, (B) porous particles having a specific surface area of 9 m ² / g or more, and (C) a conductive agent. It is disclosed.

JP 2010-197936 A JP 2010-102016 A JP 2009-175427 A

  An object of the present invention is to provide a charging member in which the occurrence of uneven charging is suppressed as compared with the case where the electron emission energy on the surface is out of the following range.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive support;
A surface layer disposed on the conductive support;
With
A charging member having a surface electron emission energy of 10 cps ^0.5 / eV or less.

The invention according to claim 2
The charging member according to claim 1, wherein the surface layer contains a conductive agent containing phosphorus-doped tin oxide.

The invention according to claim 3
The charging member according to claim 2, wherein the conductive agent is at least one selected from phosphorus-doped tin oxide particles and conductive metal oxide particles coated with phosphorus-doped tin oxide.

The invention according to claim 4
The said surface layer contains resin, The content rate of the electrically conductive agent containing the said phosphorus dope type tin oxide in the said surface layer is 5 mass parts or more and 180 mass parts or less with respect to 100 mass parts of said resin. Item 4. The charging member according to Item 3.

The invention according to claim 5
The charging member according to claim 2, wherein the surface layer further contains carbon black.

The invention according to claim 6
The surface layer contains a resin, and the content of the conductive agent containing the phosphorus-doped tin oxide in the surface layer is 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the resin.
The content ratio of the conductive agent containing phosphorus-doped tin oxide and the carbon black (conductive agent containing phosphorus-doped tin oxide: carbon black (mass ratio)) is 10:25 to 100: 5. Charging member.

The invention according to claim 7 provides:
The charging member according to claim 2, wherein the surface layer further contains a filler.

The invention according to claim 8 provides:
The charging member according to claim 1, which is used for charging by a direct current charging method.

The invention according to claim 9 is:
A charging device comprising the charging member according to claim 1, wherein the charging member is charged by bringing the charging member into contact with a surface of a member to be charged.

The invention according to claim 10 is:
An image carrier,
And a charging device according to claim 9 for charging the image carrier.
A process cartridge attached to and detached from the image forming apparatus.

The invention according to claim 11 is:
The process cartridge according to claim 10, wherein the image carrier is an electrophotographic photosensitive member having at least a surface layer having a charge transporting property of 25 μm or more on a substrate.

The invention according to claim 12
The process cartridge according to claim 10 or 11, wherein a rotation speed of the charging member is 100 mm / s or less.

The invention according to claim 13 is:
An image carrier,
The charging device according to claim 9, wherein the image holding body is charged.
A latent image forming apparatus for forming a latent image on the surface of the charged 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;
A transfer device for transferring the toner image formed on the surface of the image carrier to a recording medium;
An image forming apparatus comprising:

The invention according to claim 14 is:
The image forming apparatus according to claim 13, wherein the image holding member is an electrophotographic photosensitive member having at least a surface layer having a charge transporting property of 25 μm or more on a substrate.

The invention according to claim 15 is:
The image forming apparatus according to claim 13, wherein a rotation speed of the charging member is 100 mm / s or less.

  According to the first aspect of the present invention, there is provided a charging member in which the occurrence of uneven charging is suppressed as compared with the case where the surface electron emission energy is out of the range.

  According to the second and third aspects of the present invention, there is provided a charging member in which the occurrence of uneven charging is suppressed as compared with the case where the surface layer contains only carbon black as a conductive agent.

  According to the fourth aspect of the present invention, there is provided a charging member in which the occurrence of charging unevenness is suppressed as compared with the case where the content of the conductive agent containing phosphorus-doped tin oxide in the surface layer is out of the above range.

  According to the fifth aspect of the present invention, compared to the case where the surface layer contains only the conductive agent containing phosphorus-doped tin oxide as the conductive agent, the occurrence of charging unevenness is suppressed while reducing the content of the conductive agent. A charging member is provided.

  According to the invention described in claim 6, when at least one of the content ratio of the conductive agent containing phosphorus-doped tin oxide and the content ratio of the conductive agent containing phosphorus-doped tin oxide and carbon black in the surface layer is out of the above range. Compared to the above, a charging member in which the occurrence of uneven charging is suppressed is provided.

  According to the seventh aspect of the present invention, there is provided a charging member in which the occurrence of uneven charging after repeated charging is suppressed as compared with the case where the surface layer does not contain a filler.

  According to the eighth aspect of the present invention, there is provided a charging member in which the occurrence of charging unevenness is suppressed even when it is used for charging by a DC charging method as compared with the case where the surface electron emission energy is out of the range. Provided.

  According to the ninth aspect of the present invention, there is provided a charging device in which the occurrence of uneven charging is suppressed as compared with the case where a charging member whose surface electron emission energy is out of the above range is used.

  According to the invention described in claims 10 and 13, the process cartridge and the image in which the occurrence of image defects due to charging unevenness is suppressed as compared with the case of using a charging member whose surface electron emission energy is out of the above range. A forming apparatus is provided.

  According to the invention described in claims 11 and 14, the image carrier has a charge transporting property having a thickness of 25 μm or more on the substrate as compared with the case where a charging member whose surface electron emission energy is outside the above range is used. A process cartridge and an image forming apparatus in which occurrence of image defects due to charging unevenness is suppressed even with an electrophotographic photosensitive member having a surface layer are provided.

  According to the inventions of claims 12 and 15, even when the charging member has a rotational speed of 100 mm / s or less, the charging unevenness is smaller than when a charging member whose surface electron emission energy is out of the above range is used. A process cartridge and an image forming apparatus in which the occurrence of image defects due to the above are suppressed are provided.

It is a schematic sectional drawing of an 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. 1 is a schematic diagram illustrating a basic configuration of an image forming apparatus according to a first embodiment. FIG. 4 is a schematic diagram illustrating a basic configuration of an image forming apparatus according to a second embodiment. It is the schematic which shows the basic composition of the image forming apparatus which concerns on 3rd Embodiment. It is the schematic which shows an example of the process cartridge which concerns on this embodiment. It is a graph which shows the measurement result of the variation | change_quantity of the photoelectron emission number when increasing the energy amount irradiated to the surface of a measurement sample in steps.

  Hereinafter, embodiments of the present invention will be described in detail.

[Charging member]
The charging member according to the present embodiment includes at least a conductive support and a surface layer disposed on the conductive support. The electron emission energy on the surface of the charging member is 10 cps ^0.5 / eV or less.

As a means for charging the object to be charged, a contact-type charging member that performs charging by contacting the surface of the object to be charged is used. For example, at least a surface layer is provided on a conductive support, and the surface layer is electrically conductive. For example, a charging member containing a conductive agent is used in order to impart properties.
However, with these contact-type charging members, it is not easy to suppress electrical unevenness, and charging unevenness, that is, a phenomenon in which the amount of charge with respect to an object to be charged varies depending on the location. Therefore, for example, when this contact-type charging member is used as a charging member for charging an image carrier (electrophotographic photosensitive member) in an image forming apparatus, uneven charging occurs on the image carrier, resulting in formation. In some cases, image defects (color points, white spots, streaky image defects extending in the axial direction (direction intersecting with the conveyance direction of the recording medium), etc.) due to uneven charging may occur.

Note that in a contact-type charging device using a charging member, there are a DC charging method in which only a direct current is applied as a method for applying a voltage, and an alternating current superimposing method (AC charging method) in which alternating current is superimposed on direct current. The DC charging method is preferable in that it has an advantage that it is easier to suppress the wear of the photoconductor, the generation of discharge noise due to vibration of the photoconductor is also suppressed as compared to the AC charging method, and the power supply cost is easily reduced. Used for. However, the above uneven charging tends to occur more than the AC charging method.
In addition, when the image carrier (electrophotographic photosensitive member) as a member to be charged is provided with a surface layer having charge transporting property, the above-described charging unevenness is caused by the thickness of the surface layer having charge transporting property (charge transporting property on the surface). In the case where a plurality of layers having a thickness of 2 are laminated, the total thickness) of the plurality of layers tends to be generated more, particularly when the thickness is 25 μm or more.
Further, as the driving speed (rotational speed) of the charging member is slow, that is, as the time until the contacted portion between the charging member and the member to be charged comes into contact with each other is longer, the charging unevenness tends to occur more. In particular, it has been more generated when the rotation speed of the charging member is 100 mm / s or less.

  Further, the charging member may come into contact with the object to be charged and repeatedly adhere to the surface. For example, when it is used in an image forming apparatus, toner or external additives adhere to the surface. Sometimes. When such deposits occur, it becomes more difficult to suppress uneven charging, that is, the charging unevenness tends to occur after repeated charging.

On the other hand, in this embodiment, since the electron emission energy on the surface of the charging member is 10 cps ^0.5 / eV or less, the occurrence of the charging unevenness is suppressed.
The reason why this effect is achieved is not necessarily clear, but in the charging process by the charging member, not only the conductivity in the surface layer contributes, but also the discharge from the surface of the surface layer has an effect. it is conceivable that. That is, since it is required that the electron emission from the surface is controlled and the discharge is appropriately generated, it is presumed that the uneven charging is suppressed by the electron emission energy on the surface being in the above range.
Further, not only the initial charging unevenness but also the occurrence of charging unevenness after repeated charging is suppressed. This is considered to be because excellent electron-emitting properties are continuously exhibited even when the surface of the charging member is contaminated with deposits, and the discharge is controlled within an appropriate range.
As a result, by using the charging member according to the present embodiment in an image forming apparatus, image defects (color point, white point, and axial direction (direction intersecting with the conveyance direction of the recording medium)) caused by uneven charging in the image. Occurrence of an elongated streak-like image defect or the like) is also satisfactorily suppressed.

・ Surface electron emission energy (electron emission)
The surface electron emission energy (electron emission) means the amount of change in the number of photoemissions when the amount of energy applied to the surface is increased stepwise, especially when electrons start to be emitted. Change amount (cps ^0.5 / eV) is used. Surface electron emission energy is measured by irradiating a surface layer measurement sample with ultraviolet light that has been dispersed with a monochromator while changing the energy in an air atmosphere, and determining the energy at which photoelectrons begin to be emitted by the photoelectric effect. It is.
Specifically, from a charging member, a measurement sample of a surface layer (including an elastic layer if an elastic layer is included) is collected by a cutter or the like, and using an atmospheric photoelectron spectrometer AC-2 manufactured by Riken Keiki Co., Ltd. The electron emission energy (cps ^0.5 / eV) is measured.
FIG. 7 shows the measurement results of the amount of change in the number of photoelectrons emitted when the amount of energy applied to the surface of the measurement sample is increased stepwise using the atmospheric photoelectron spectrometer AC-2. The amount of increase in photoemission (the slope of the electron emission line in FIG. 7) is defined as electron emission energy.

In the charging member according to the present embodiment, the surface electron emission energy is 10 cps ^0.5 / eV or less, ^preferably 2 cps ^0.5 / eV or more and 10 cps ^0.5 / eV or less, preferably 2 cps ^0.5 / e. more preferably eV or more ^8cps is 0.5 / eV or ^less, and more preferably not more than ^{4 cps} 0.5 / eV or ^{6 cps} 0.5 / eV. When the electron emission energy is within the above range, it is considered that the discharge from the surface of the charging member is controlled to be within a range, and the occurrence of the uneven charging is more effectively suppressed. Note that the electron emission energy on the surface of the charging member is determined not only by the type of material used, but also by the formulation, surface properties, and the like.

-Inclusion of conductive agent containing phosphorus-doped tin oxide In this embodiment, the surface layer preferably contains a conductive agent containing phosphorus-doped tin oxide (hereinafter also simply referred to as "phosphorus-doped tin oxide-containing conductive agent"). By including the phosphorus-doped tin oxide-containing conductive agent, the electron emission energy on the surface of the charging member can be easily controlled within the above range. In addition, the conductivity of the surface layer is controlled by the inclusion of the phosphorus-doped tin oxide-containing conductive agent, and the electron emission from the surface is also controlled to the required range, so that discharge can be generated appropriately. It is conceivable that the charging unevenness is further suppressed by these contributions.
Examples of the phosphorus-doped tin oxide-containing conductive agent include phosphorus-doped tin oxide particles and conductive metal oxide particles coated with phosphorus-doped tin oxide. Details of these will be described later.

-Content of phosphorus-doped tin oxide-containing conductive agent The content of phosphorus-doped tin oxide-containing conductive agent in the surface layer (ratio to 100 parts by mass of resin (polymer material) in the surface layer) is not particularly limited. However, it is preferably 5 to 180 parts by mass, more preferably 10 to 170 parts by mass, and still more preferably 20 to 160 parts by mass.

  In addition, when not using together with other conductive agents (conductive agents not containing phosphorus-doped tin oxide) as a conductive agent, but using only a phosphorus-doped tin oxide-containing conductive agent, the inclusion of a phosphorus-doped tin oxide-containing conductive agent in the surface layer The ratio (ratio to 100 parts by mass of the resin (polymer material) in the surface layer) is not particularly limited, but is preferably 80 parts by mass or more and 180 parts by mass or less, and 110 parts by mass or more and 170 parts by mass. The following is more preferable, and 120 to 160 parts by mass is further preferable.

  When the content of the phosphorus-doped tin oxide-containing conductive agent is in the above range, the occurrence of uneven charging at the initial stage and the occurrence of uneven charging after repeated charging are satisfactorily suppressed. This is considered to be because the content of the phosphorus-doped tin oxide-containing conductive agent is controlled to a range in which the conductivity of the surface layer is required by being equal to or higher than the above lower limit, and the surface by being equal to or lower than the upper limit. This is because the degree of discharge from the layer is controlled within a required range.

Carbon black It is preferable that the surface layer further contains carbon black as a conductive agent. By using carbon black together, even if the content of the entire conductive agent is reduced, the effect of suppressing uneven charging can be satisfactorily exhibited. In other words, the effect of suppressing uneven charging can be achieved while reducing the amount of conductive agent.

-Content rate of phosphorus-doped tin oxide-containing conductive agent and carbon black When using phosphorus-doped tin oxide-containing conductive agent and carbon black in combination, the content of phosphorus-doped tin oxide-containing conductive agent in the surface layer (resin in the surface layer ( The ratio of the polymer material) to 100 parts by mass is not particularly limited, but is preferably 5 parts by mass or more and 180 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, and 20 parts by mass. More preferred is 60 parts by mass or less. By being in the above range, the occurrence of uneven charging at the initial stage and the occurrence of uneven charging after repeated charging are satisfactorily suppressed.

Moreover, the content ratio of the phosphorus-doped tin oxide-containing conductive agent and carbon black (phosphorus-doped tin oxide-containing conductive agent: carbon black (mass ratio)) is not particularly limited, but the following ranges are preferable.
-10:25 (= 0.4: 1) thru | or 100: 5 (= 20: 1) are preferable.
20:15 (≈1.33: 1) to 80:10 (= 8: 1) is more preferable.
20:15 (≈1.33: 1) to 60:10 (= 6: 1) is more preferable.
By being in the above range, the occurrence of charging unevenness in the initial stage and the occurrence of charging unevenness after repeated charging can be suppressed more satisfactorily.

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

The form of the charging member includes, but is not particularly limited to, a roll shape, a sheet shape, a blade shape, etc. Among them, at least the surface layer on the outer peripheral surface of a cylindrical or columnar conductive support. A roll-shaped charging roll provided with is preferable.
Below, the structure is demonstrated taking the charging roll which is one form of the charging member as an example.

FIG. 1 is a schematic cross-sectional view perpendicular to the axis of the 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 sectional view in a 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 an adhesive layer 32, an elastic layer 33, an intermediate layer 34, and a surface layer 35 on a conductive support 31.
Note that 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 it includes the conductive support and the surface layer having the above-described configuration. For example, the adhesive layer 32 shown in FIGS. 1 and 2 may not be provided.
Hereinafter, the configuration of the charging roll shown in FIG. 1 will be mainly described. In the following description, reference numerals may be omitted.

In this specification, the term “conductive” means that the volume resistivity at 20 ° C. is less than 1 × 10 ¹³ Ωcm.

(Conductive support)
The conductive support 31 will be described.
The conductive support 31 functions as an electrode and a support member for the charging roll, and is made of a metal or alloy such as aluminum, copper alloy, or stainless steel; iron plated with chromium, nickel, or the like, such as JIS G4804. The free-cutting steel shown is made of a material plated with chromium, nickel, or the like. The plating may be formed by an electrolytic plating method or an electroless plating method, and is not limited.

(Adhesive layer)
Although the material which forms the contact bonding layer 32 is not specifically limited, For example, polyolefin type, chlorine rubber type, acrylic type, epoxy type, polyurethane type, nitrile rubber type, vinyl chloride type, vinyl acetate type, polyester type, phenol type, silicone From the viewpoint of adhesion to rubber and elastomer forming the elastic layer, polyolefin-based and phenol-based materials are particularly preferable.

The adhesive layer may have a single layer configuration or a combination of a plurality of layers.
Carbon black such as conductivity imparted ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, 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; the surface of an insulating material made conductive; Good.

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

(Elastic layer)
The elastic layer 33 is a member having a function of imparting elasticity to the charging member according to the present embodiment. By providing the elastic layer, a nip with the member to be charged is favorably formed. The charging member including the elastic layer tends to cause the above-described charging unevenness with the formation of the nip with the member to be charged. The occurrence of uneven charging is suppressed satisfactorily.

-Rubber component-
The elastic layer can be formed of rubber components such as various rubbers and elastomers.
As the rubber component, epichlorohydrin rubber is preferable from the viewpoint of suppressing resistance unevenness, and epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber and the like are particularly preferable.
The elastic layer preferably contains the epichlorohydrin rubber as a main component. “Epichlorohydrin rubber as the main component” means that the rubber component contained in the rubber composition forming the elastic layer contains the most epichlorohydrin rubber, and the epichlorohydrin rubber is included in the rubber component. The amount is preferably 50% by mass or more, more preferably 90% by mass or more, and all the rubber components are particularly preferably (100% by mass) epichlorohydrin rubber.

Other rubber components used in combination with the epichlorohydrin rubber or other rubber components used in place of the epichlorohydrin rubber include, for example, isoprene rubber, chloroprene rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, and styrene-butadiene rubber. Butadiene rubber, nitrile rubber, ethylene propylene rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber and the like.
A rubber component may be used independently and may be used in combination of 2 or more type.

-Conductive agent-
A conductive agent may be added to the elastic layer from the viewpoint of imparting conductivity. As the conductive agent, an electronic conductive agent or an ionic conductive agent is used.
Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; tin oxide, indium oxide, titanium oxide And various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution;

  Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals ;

These conductive agents may be used alone or in combination of two or more.
Further, the amount of addition is not particularly limited, but in the case of the electronic conductive agent, it is preferably in the range of 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the rubber component. A range of 25 parts by mass or less is more preferable.
On the other hand, in the case of the ionic conductive agent, it is preferably in the range of 0.1 parts by mass or more and 5.0 parts by mass or less, and 0.5 parts by mass or more and 3.0 parts by mass with respect to 100 parts by mass of the rubber component. The following range is more preferable.

-Crosslinking agent-
In the case of crosslinking the rubber component, materials such as a crosslinking agent and a crosslinking accelerator are further used. Generally, the types of cross-linking with a cross-linking agent include sulfur cross-linking, peroxide cross-linking, quinoid cross-linking, phenolic resin cross-linking, amine cross-linking, metal oxide cross-linking, etc., but cross-linking with materials having double bonds. From the viewpoint of easy handling and the flexibility of the crosslinked rubber, crosslinking with sulfur is preferred. Even in the sulfur cross-linking, cross-linking using a cross-linking agent that releases activated sulfur from a compound is preferable because it can shorten the distance between bonds, and 4,4′-dithiodimorpholine is preferable.

  Examples of the crosslinking accelerator include thiazole, thiuram, sulfenamide, thiourea, dithiocarbamate, guanidine, aldehyde-ammonia, and mixtures thereof.

-Other additives-
Further, the rubber composition forming the elastic layer in the present embodiment may contain other additives as necessary. Examples of other additives include fillers and crosslinking accelerators.
Other fillers include silica, calcium carbonate, clay and the like.
Examples of the vulcanization acceleration aid include blending of zinc oxide and the like.

  The amount of other additives added is in the range of 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the rubber component, including particles such as carbon black and zinc oxide as a vulcanization acceleration aid. Is preferable, and the range of 20 parts by mass or more and 80 parts by mass or less is more preferable.

  The constituent material (rubber composition) of the elastic layer may be used as a constituent material of the resistance layer when the resistance layer is formed.

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 from 10 ³ Ωcm to 10 ¹⁴ Ωcm.

-Formation of elastic layer-
The elastic layer is prepared, for example, by kneading a mixture of the components listed above to prepare a composition for forming an elastic layer, and using an extrusion molding machine, an injection molding machine, a press molding machine or the like equipped with a crosshead. Then, the composition is formed by extruding and vulcanizing the composition on the conductive support.

(Surface layer)
The surface layer preferably includes at least a conductive agent and a resin. Moreover, you may be comprised including the filler for adjusting the surface roughness of a surface layer, another additive, etc.

-Conductive agent-
In this embodiment, it is preferable that the surface layer contains a conductive agent containing phosphorus-doped tin oxide.
Examples of the shape of the phosphorus-doped tin oxide-containing conductive agent include particles. The particle shape of the phosphorus-doped tin oxide-containing conductive agent is not particularly limited, but for example, a spherical shape is preferable.

Although it does not specifically limit as a primary particle diameter (number average particle diameter) of a phosphorus dope type tin oxide containing electrically conductive agent, The range of 20 nm or less is preferable, and 8 nm or more and 12 nm or less are more preferable.
The primary particle size (number average particle size) of the phosphorus-doped tin oxide-containing conductive agent is measured using a scanning electron microscope (SEM). In addition, let an average particle diameter be the average value of the particle diameter measured about several particle | grains.

  Examples of the phosphorus-doped tin oxide-containing conductive agent include phosphorus-doped tin oxide particles and conductive metal oxide particles coated with phosphorus-doped tin oxide.

Phosphorus-doped tin oxide particles The powder specific resistance (volume resistivity) of the phosphorus-doped tin oxide particles is not particularly limited, but is preferably in the range of 1 Ω · cm to 100 Ω · cm, and preferably 5 Ω · cm to 50 Ω. More preferably, it is not more than cm, more preferably not less than 10Ω · cm and not more than 40Ω · cm.
In addition, the measurement of the powder specific resistance is performed by solidifying the phosphorus-doped tin oxide particles, preparing a measurement sample, and measuring the resistance with a resistance measuring device that can apply a fine current, and measuring the powder multiple times. Go and adopt the average value.

  Specific examples of commercially available phosphorus-doped tin oxide particles include SP-2 manufactured by Mitsubishi Materials Electronic Chemicals.

Conductive metal oxide particles coated with phosphorus-doped tin oxide Conductive metal oxide particles coated with phosphorus-doped tin oxide (hereinafter also simply referred to as “P-doped tin oxide-coated conductive agent particles”) Conductive metal oxide particles whose surface is coated with tin.
Examples of the conductive metal oxide include titanium oxide, indium oxide, tin oxide, tin oxide-antimony oxide solid solution, and tin oxide-indium oxide solid solution. Among these, titanium oxide is more preferable.

  The coating amount of phosphorus-doped tin oxide (the mass ratio of phosphorus-doped tin oxide to the total amount (mass) of conductive metal oxide coated with phosphorus-doped tin oxide) is not particularly limited, and depends on the required performance Can be adjusted.

  Specific examples of commercially available P-doped tin oxide-coated conductive agent particles include W-4 (titanium oxide coated with phosphorus-doped tin oxide) manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.

Other conductive agents Other conductive agents other than the phosphorus-doped tin oxide-containing conductive agent may be used in combination on the surface layer.
Other conductive agents that can be used in combination with the surface layer include electronic conductive agents and ionic conductive agents. Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; tin oxide, indium oxide, titanium oxide And various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals ; These other conductive agents may be used alone or in combination of two or more.

Among the above, carbon black is preferable as the other conductive agent used in combination with the phosphorus-doped tin oxide-containing conductive agent. By using a phosphorus-doped tin oxide-containing conductive agent and carbon black in combination, even if the total content of the conductive agent is reduced, the effect of suppressing uneven charging can be demonstrated well. In other words, charging unevenness can be suppressed while reducing the amount of conductive agent. Both effects can be achieved.
The carbon black is not particularly limited, but is preferably an acidic type carbon black.

  Here, as a commercially available product of carbon black, specifically, “MONARCH1000”, “MONARCH1300”, “MONARCH1400”, “MOGUL-L”, “REGAL400R” manufactured by Cabot Corporation, manufactured by Orion Engineered Carbons “Special Black 350”, “Special Black 100”, “Special Black 250”, “Special Black 5”, “Special Black 4”, “Special Black 4A”, “Special Black 550”, “ Special Black 6 ”,“ Color Black FW200 ”,“ Color Black FW2 ”,“ Color Black FW2V ”, and the like.

  The content of the phosphorus-doped tin oxide-containing conductive agent in the surface layer is preferably in the above range. Moreover, the preferable content rate when using only a phosphorus dope-type tin oxide containing conductive agent, without using together with another electroconductive agent (electrically conductive agent which does not contain phosphorus dope type tin oxide) as a conductive agent, phosphorus dope type tin oxide containing conductive agent and carbon The preferred content when black is used in combination, the preferred content ratio of the phosphorus-doped tin oxide-containing conductive agent and carbon black in that case, and the like are also as described above.

-Filler-
A filler may be added to the surface layer from the viewpoint of controlling electric characteristics and forming a convex portion with surface roughness. By adding a filler, the surface roughness of the surface layer is controlled within an appropriate range, and contamination due to adhesion of substances (for example, toner and external additives) on the surface of the charging member is suppressed, and charging is repeated. The occurrence of the charging unevenness after the heating is further suppressed.

The filler may be either conductive particles or non-conductive particles, but non-conductive particles are desirable.
As electroconductive particle, the particle | grains of the material mentioned as said electroconductive agent added to a surface layer are mentioned. Non-conductive particles include resin particles (polyamide resin particles, polyimide resin particles, methacrylic resin particles, polystyrene resin particles, fluorine resin particles, silicone resin particles, etc.), inorganic particles (clay particles, kaolin particles, talc particles, silica particles). , Alumina particles, etc.), or ceramic particles. One type of filler may be used alone, or two or more types may be used in combination.
The filler may be particles composed of the same type of resin as described later (polymer material). Conductivity means that the volume resistivity is less than 10 ¹³ Ωcm, and non-conductivity means that the volume resistivity is 10 ¹³ Ωcm or more.

Although there is no restriction | limiting in particular in content of a filler, It is preferable that it is the range of 1 mass part or more and 100 mass parts or less with respect to 100 mass parts of below-mentioned resin (polymer material), 5 mass parts or more and 60 mass parts The following range is more preferable.
The surface roughness Rz of the surface layer formed by the filler is preferably 2 μm or more and 15 μm or less from the viewpoint of suppressing unevenness in charging, and more preferably 3 μm or more and 10 μm or less.
In this embodiment, the surface roughness Rz is the ten-point average roughness Rz of JIS B0601 (1994). For the surface roughness Rz, a surface roughness measuring machine (Surfcom 1400 manufactured by Tokyo Seimitsu Co., Ltd.) was used, and the measurement target 3 was measured under the conditions of a cutoff of 0.8 mm, a measurement length of 4.0 mm, and a traverse speed of 0.3 mm / sec. A place (for example, in the case of a roll, 20 mm positions at both ends in the axial direction and three places at the center) is measured, and the average value is calculated.

-Resin-
The surface layer may include a resin (polymer material). The resin (polymer material) constituting the surface layer is not particularly limited, but is polyamide, polyurethane, polyvinylidene fluoride, tetrafluoroethylene. Copolymer, polyester, polyimide, silicone resin, acrylic resin, polyvinyl butyral, ethylene tetrafluoroethylene copolymer, melamine resin, fluoro rubber, epoxy resin, polycarbonate, polyvinyl alcohol, cellulose, polyvinylidene chloride, polyvinyl chloride, polyethylene , Ethylene vinyl acetate copolymer, copolymer nylon and the like.
The above resins may be used alone or in combination of two or more. In the case of a crosslinkable resin, it may be used after being crosslinked. The number average molecular weight of the 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.

Examples of other additives in the surface layer include materials that can be added to the normal surface layer such as a curing agent, a vulcanizing agent, a vulcanization accelerator, an antioxidant, a dispersant, a surfactant, and a coupling agent. Can be mentioned.
The thickness of the surface layer is desirably 1 μm or more and 20 μm or less, and more desirably 3 μm or more and 15 μm or less. The volume resistivity of the surface layer is preferably 10 ³ Ωcm or more and 10 ¹⁴ Ωcm or less.

-Formation of surface layer-
The surface layer can be formed by preparing a coating solution by dispersing the resin, conductive agent or the like in a solvent, applying the coating solution on an elastic layer prepared in advance, and drying the coating solution. Examples of the application method of the coating liquid include a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method.
The solvent used in the coating solution is not particularly limited, and general solvents are used. For example, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; diethyl ether and dioxane Solvents such as ethers may be used.

[Charging device]
The charging device according to the present embodiment includes the charging member according to the present embodiment.
The charging device according to the present embodiment may be configured by only the charging member according to the present embodiment, for example, or the charging member and the cleaning member according to the present embodiment are arranged in contact with each other with a specific biting amount. It may be a configuration.

  As a method for applying a voltage to the charging member, there are a DC charging method in which only a DC voltage is applied, and an AC superposition method in which an AC voltage is superimposed on the DC voltage and applied. In the present embodiment, a DC charging method by applying a DC voltage is preferable from the viewpoint of wear of the photoconductor, generation of ozone, and discharge noise due to vibration of the photoconductor. Note that the above-described charging unevenness is more likely to occur in the direct current charging method than in the alternating current charging method. However, according to the present embodiment, even when the direct current charging method is adopted, the occurrence of the uneven charging is good. To be suppressed.

-Use-
The charging device including the charging member according to the present embodiment is used for the purpose of charging the object to be charged while being in contact with the object to be charged. For example, it is preferably used as a charging member in an image forming apparatus, and specifically, a charging member for charging an image carrier (electrophotographic photosensitive member), and toner is transferred from the image carrier (electrophotographic photosensitive member) to a recording medium. Used as a transfer member or the like.

[Image forming apparatus]
An image forming apparatus according to the present embodiment includes an image carrier, and a charging device that includes the charging member according to the present embodiment and charges the image carrier by bringing the charging member into contact with the surface of the image carrier. A latent image forming device that forms a latent image on the surface of the charged image carrier, a developing device that forms a toner image by developing the latent image formed on the surface of the image carrier with the toner, and the image carrier A transfer device that transfers the toner image formed on the surface of the body to a recording medium.
Hereinafter, an image forming apparatus according to the present embodiment will be described with reference to the drawings.

-First embodiment-
FIG. 3 is a schematic diagram illustrating a basic configuration of the image forming apparatus according to the first embodiment. An image forming apparatus 200 shown in FIG. 3 includes an electrophotographic photosensitive member (an example of an image holding member) 207, a charging device 208 that charges the electrophotographic photosensitive member 207, a power source 209 connected to the charging device 208, and a charging device. An exposure apparatus (an example of a latent image forming apparatus) 206 that exposes an electrophotographic photosensitive member 207 charged by 208 to form a latent image, and a latent image formed by the exposure apparatus 206 is developed with toner to form a toner image. A developing device 211 to be formed, a transfer device 212 that transfers 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 are provided. Note that the static eliminator 214 illustrated in FIG. 3 may not be provided.

  The electrophotographic photosensitive member 207 is not particularly limited, and a known electrophotographic photosensitive member can be used. For example, an undercoat layer, a charge generation layer, and a charge transport layer are laminated in this order on a conductive substrate, and a function-separated type photosensitive layer in which the charge generation layer and the charge transport layer are separately provided is provided. Examples include a photoreceptor. Further, it may be a photoreceptor having a function-integrated type photosensitive layer having both charge generation ability and charge transport ability. Further, the electrophotographic photoreceptor 207 may not include an undercoat layer, or an intermediate layer may be provided between the undercoat layer and the photosensitive layer, or a protective material including a charge transport material on the photosensitive layer. A layer may be provided.

In the electrophotographic photosensitive member 207 according to this embodiment, the total thickness of the surface layers having charge transporting properties is preferably 25 μm or more from the viewpoint of suppressing the occurrence of image defects and extending the lifetime, and is 25 μm or more. More preferably, it is 32 μm or less.
However, as the thickness of the surface layer having the charge transport property in the electrophotographic photosensitive member 207 increases, the above-described charging unevenness tends to occur more, particularly when the thickness is 25 μm or more. . On the other hand, in the present embodiment, by providing the charging member according to the present embodiment, even if the thickness of the surface layer having the charge transporting property is 25 μm or more, the occurrence of the charging unevenness is further suppressed. The

  Here, in the present embodiment, the “surface layer having charge transport properties” of the photoreceptor means a charge transport layer when the charge transport layer containing the charge transport material is the outermost surface layer in the function-separated type photosensitive layer. And a protective layer containing a charge transport material on the charge transport layer is the total thickness of the charge transport layer and the protective layer, and the function-integrated type photosensitive layer containing the charge transport material is the outermost surface. In the case of a layer, this is the photosensitive layer, and in the case where a protective layer containing a charge transport material is provided on the function-integrated type photosensitive layer, the total thickness of the photosensitive layer and the protective layer.

  The charging device 208 is of a type (contact charging method) in which a charging member (charging roll) is brought into contact with the surface of the electrophotographic photosensitive member 207 to charge the surface of the photosensitive member 207, and according to the above-described embodiment. A charging device including a charging member is used.

Here, in the image forming apparatus 200, the rotation speed (process speed) of the electrophotographic photosensitive member 207 is set according to the image to be formed, the type of the recording medium 500 to be used, and the like. In addition, the driving speed (rotational speed) of the charging member (charging roll) in the charging device 208 is also adjusted. For example, as the recording medium 500 is a thick recording medium such as thick paper, the rotation speed of the electrophotographic photosensitive member 207 becomes slower and the driving speed (rotation speed) of the charging roll tends to be set slower.
As the driving speed (rotation speed) of the charging roll is slower, that is, as the time from contact of a certain portion between the charging roll and the electrophotographic photosensitive member 207 to contact is longer, the charging unevenness is increased. It was more likely to occur, particularly when the rotation speed of the charging roll was 100 mm / s or less. On the other hand, in the present embodiment, by providing the charging roll according to the present embodiment, even if the rotation speed of the charging roll is 100 mm / s or less, the occurrence of the charging unevenness is more effectively suppressed.

  As the exposure device 206, an optical system device that can expose a light source such as a semiconductor laser, an LED (light emitting diode), and a liquid crystal shutter on the surface of the electrophotographic photosensitive member in a desired image-like manner can be used.

  The developing device 211 stores toner. The toner used in the present embodiment includes, 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. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can also be mentioned.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. 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 is a typical example.

The toner may be internally added or externally added with known additives such as a charge control agent, a release agent, and other inorganic particles.
Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.
Known charge control agents can be used, but charge control agents such as azo-based metal complex compounds, metal complex compounds of salicylic acid, and resin types containing polar groups can be used.

As other inorganic particles, small-diameter inorganic particles having an average primary particle size of 40 nm or less are used for the purpose of powder fluidity, charge control, and the like. Inorganic or organic particles may be used in combination. As these other inorganic particles, known ones can be used.
In addition, the surface treatment of the small-diameter inorganic particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  As a method for producing the toner used in the exemplary embodiment, a polymerization method such as an emulsion polymerization aggregation method or a dissolution suspension method is preferably used because high shape controllability can be obtained. In addition, a manufacturing method may be performed in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered 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. In addition, when the toner is manufactured by a wet method, the toner may be added by a wet method.

  The transfer device 212 is capable of supplying a current having a predetermined current density toward the electrophotographic photosensitive member when the toner image formed on the electrophotographic photosensitive member 207 is transferred to the recording medium 500. Is preferred.

  The cleaning device 213 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process. The cleaned electrophotographic photosensitive member is repeatedly used for the image forming process described above. . As the cleaning device, brush cleaning, roll cleaning, and the like can be used in addition to the cleaning blade. Among these, it is preferable to use the cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  In addition, 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 eliminator for removing the residual potential of the electrophotographic photosensitive member. As a result, when the electrophotographic photosensitive member is repeatedly used, the phenomenon that the residual potential of the electrophotographic photosensitive member is brought into the next cycle is prevented, so that the image quality can be further improved.

-Second Embodiment-
FIG. 4 is a schematic diagram illustrating a basic configuration of an 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 it between the primary transfer member 212a and the secondary transfer member 212b. In this transfer, a current having 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 as in the image forming apparatus 200 shown in FIG. Other configurations of the image forming apparatus 210 are the same as those of the image forming apparatus 200.
As described above, the image forming apparatus 210 is different 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. By combining with the charging device including the charging member according to the embodiment, the occurrence of image defects is suppressed.

  Further, when the toner image formed on the electrophotographic photosensitive member 207 is transferred to the primary transfer member 212a, a current having a predetermined current density is supplied from the primary transfer member 212a to the electrophotographic photosensitive member 207. As a result, fluctuations in the transfer current due to the type and material of the recording medium 500 can be suppressed, 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 burden at a higher level.

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

  Each of the electrophotographic photoreceptors 401a to 401d can be rotated in a specific direction (counterclockwise on the paper surface), and charging members (charging rolls) 402a to 402d, developing devices 404a to 404d, and 1 are provided along the rotation direction. Next transfer rolls 410a to 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can supply toner of four colors, black, yellow, magenta, and cyan accommodated in the toner cartridges 405a to 405d. Further, the primary transfer rolls 410a to 410d are in contact with the electrophotographic photosensitive members 401a to 401d via the intermediate transfer belt 409, respectively.

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

  The intermediate transfer belt 409 is supported with tension by a drive roll 406, a back roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. The secondary transfer roll 413 is disposed so as to contact the back roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 that has passed between the back roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  In addition, 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 moved between the intermediate transfer belt 409 and the secondary transfer roll 413 by the transfer roll 412. Further, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. There may be.

[Process cartridge]
A process cartridge according to the present embodiment includes an image carrier, and a charging device that includes the charging member according to the present embodiment and charges the image carrier by bringing the charging member into contact with the surface of the image carrier. And is attached to and detached from the image forming apparatus.

FIG. 6 is a schematic view showing an example of a process cartridge according to the present embodiment. A 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 static elimination exposure. 218 is 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 attached to an image forming apparatus main body including a transfer device 212, a fixing device 215, and other components (not shown), and the image forming apparatus together with the image forming apparatus main body. Configure.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example. Unless otherwise specified, “part” means “part by mass”.

(Preparation of electrophotographic photoreceptor 1)
Zinc oxide: (average particle size 70 nm: manufactured by Teika: specific surface area value 15 m ² / g) 100 parts of tetrahydrofuran were stirred and mixed, and 1.25 parts of silane coupling agent (KBM603: manufactured by Shin-Etsu Chemical Co., Ltd.) was added. Added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a silane coupling agent surface-treated zinc oxide pigment.

60 parts of the surface-treated zinc oxide pigment, 0.6 parts of alizarin, curing agent: 13.5 parts of blocked isocyanate (Sumidule 3175: manufactured by Sumitomo Bayern Urethane Co., Ltd.), butyral resin (ESREC BM-1) : Sekisui Chemical Co., Ltd.) 15 parts, 38 parts of a solution obtained by dissolving 85 parts of methyl ethyl ketone and 25 parts of methyl ethyl ketone are mixed and dispersed in a sand mill for 2 hours using 1 mmφ glass beads. Got. To the obtained dispersion, 0.005 part of dioctyltin dilaurate as a catalyst and 4.0 parts of silicone resin particles (Tospearl 145: manufactured by Momentive Performance Materials) are added to form an undercoat layer. A coating solution was obtained.
This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

Next, a photosensitive layer (photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer) was formed on the formed undercoat layer as follows.
First, the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using the Cukα ray as the charge generation material is at least 7.3 °, 16.0 °, 24.9 °, 28.0 °. A mixture comprising 15 parts of hydroxygallium phthalocyanine having a diffraction peak at a position, 10 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 200 parts of n-butyl acetate Was dispersed in a sand mill for 4 hours using 1 mmφ glass beads. To the obtained dispersion, 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added and stirred to obtain a coating solution for a charge generation layer.
This charge generation layer coating solution was dip coated on the undercoat layer and dried at room temperature (22 ° C.) to form a charge generation layer having a thickness of 0.2 μm.

Next, 1 part of tetrafluoroethylene resin particles, 0.02 part of fluorine-based graft polymer, 5 parts of tetrahydrofuran, and 2 parts of toluene are sufficiently mixed by stirring to obtain a tetrafluoroethylene resin particle suspension. It was.
Next, 4 parts of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine as a charge transport material and bisphenol Z-type polycarbonate 6 parts of resin (viscosity average molecular weight 40,000) and 23 parts of tetrahydrofuran are mixed and dissolved in 10 parts of toluene, and then the tetrafluoroethylene resin particle suspension is added and stirred and mixed. Using a high-pressure homogenizer (trade name LA-33S, manufactured by Nanomizer Co., Ltd.) equipped with a penetrating chamber with a pressure of 400 kgf / cm ² (3.92 × 10 ⁻¹ Pa), the dispersion treatment was performed 6 times. Repeatedly, a tetrafluoroethylene resin particle dispersion was obtained. Further, 0.2 part of 2,6-di-t-butyl-4-methylphenol was mixed to obtain a coating solution for forming a charge transport layer. This coating solution was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 22 μm.
Thus, an electrophotographic photoreceptor 1 having a charge generation layer and a charge transport layer in this order on the undercoat layer was obtained.

(Preparation of electrophotographic photoreceptor 2)
An electrophotographic photoreceptor 2 was produced in the same manner as the electrophotographic photoreceptor 1 except that the thickness of the charge transport layer was 34 μm.

[Example A]
<Example A1>
-Production of rubber composition-
A mixture having the following composition was kneaded with a 2.5 L kneader to obtain a rubber composition A1.
・ Rubber material 100 parts (Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, Hydrin T3106: manufactured by Nippon Zeon Co., Ltd.)
-Conductive agent (carbon black # 3030B: manufactured by Mitsubishi Chemical Corporation) 5 parts-Ionic conductive agent (benzyltrimethylammonium chloride, trade name "BTEAC", manufactured by Lion Specialty Chemicals) 1 part-Vulcanizing agent (organic sulfur, 4,4'-dithiodimorpholine, Barnock R: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.5 parts ・ Vulcanization accelerator A (thiazole series, di-2-benzothiazolyl disulfide, Noxeller DM-P: large 1.5 parts ・ Vulcanization accelerator B (thiuram, tetraethylthiuram disulfide, Noxeller TET-G: made by Ouchi Shinsei Chemical Co., Ltd.) 1.8 parts ・ Vulcanization accelerator (oxidation) Zinc, zinc oxide 1 type: manufactured by Shodo Chemical Co., Ltd.) 3 parts ・ Stearic acid 1.0 part ・ Heavy calcium carbonate 40 parts

-Production of elastic rolls-
After electroless nickel plating having a thickness of 5 μm, a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid was prepared.
The rubber composition A1 is extruded at a screw rotation of 25 rpm using a uniaxial rubber extruder with a cylinder inner diameter of 60 mm and L / D20, and the conductive support is continuously passed through a crosshead, thereby providing a conductive support. The rubber composition A1 was coated on the body. The temperature conditions of the extruder were set to 80 ° C. for all of the cylinder part, screw part, head part, and die part. The unvulcanized rubber roll formed of the conductive support and the coated rubber composition was vulcanized at 165 ° C. for 70 minutes in an air heating furnace to obtain an elastic roll A1 having a diameter of 12 mm.

-Formation of surface layer-
The following mixture was dispersed with a bead mill to obtain dispersion A1. The dispersion A1 was diluted with methanol and dip-coated on the surface of the elastic roll A1, and then heated and dried at 160 ° C. for 30 minutes to form a surface layer having a thickness of 10 μm, whereby a charging roll A1 was obtained.
・ Polymer material (N-methoxymethylated nylon, F30K: manufactured by Nagase ChemteX Corporation) 100 parts ・ Polymer material (polyvinyl butyral resin, ESREC BL-1: manufactured by Sekisui Chemical Co., Ltd.) 10 parts ・ Conducting agent (phosphorus doped type) 80 parts of tin oxide particles (SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd., particle shape: spherical, powder specific resistance 22.2 Ω · cm)
Filler (polyamide resin, Orgasol 2001 DNat1: Arkema) 20 parts Catalyst (Nacure 4167: King Industry) 4 parts Solvent (methanol) 700 parts Solvent (butanol) 200 parts

≪Physical properties≫
-Surface electron emission energy-
A measurement sample was collected from the surface of the obtained charging roll with a cutter. Next, the electron emission energy (cps ^0.5 / eV) was measured on the collected measurement sample using an atmospheric photoelectron spectrometer AC-2 manufactured by Riken Keiki Co., Ltd. The results are shown in Table 1 below.

≪Evaluation test≫
-Image quality evaluation-
Copier Apeos Port-V C3320: manufactured by Fuji Xerox Co., Ltd. as a contact-type charging device for charging the image carrier (electrophotographic photosensitive member) with the electrophotographic photosensitive member 1 (charge transport layer thickness 22 μm) and the charging roll A1. The image quality was evaluated by 50%, 30%, and 0% halftone printing in the initial stage and after printing 20,000 sheets, and evaluated according to the following evaluation criteria.
In addition, said evaluation test was implemented about the case where process speed (= rotational speed of a charging roll) was set to 128 mm / s, and the case where it set to 64 mm / s.
The results are shown in Table 1 below.
A (◎): Image defects such as density unevenness, white spots, color spots, streaks have not occurred.
B (◯): Image defects such as slight density unevenness, white spots, color spots, and streaks partially occur.
C (Δ): Image defects such as slight density unevenness, white point, color point, streak occur.
D (x): Image defects such as density unevenness, white spots, color spots, streaks occur.

-Evaluation of uneven charging-
The occurrence of charging unevenness was measured and evaluated by the following method. The results are shown in Table 1 below.
A specific evaluation test method is to set an applied voltage at the time of charging to 100 V lower than usual, and then read an image obtained by printing a blank paper with a scanner, convert the total density into 255 levels, Was used as an index of charging unevenness.

<Example A2>
A charging roll was prepared and evaluated in the same manner as in Example A1, except that the surface layer conductive agent of Example A1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronic Chemicals) 130 parts

<Example A3>
A charging roll was prepared and evaluated in the same manner as in Example A1, except that the surface layer conductive agent of Example A1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 180 parts

<Example A4>
In the evaluation test of Example A2, a charging roll was prepared and evaluated in the same manner as in Example A2, except that the electrophotographic photoreceptor 1 was changed to the electrophotographic photoreceptor 2 (charge transport layer thickness 34 μm). It was shown to.

<Comparative Example A1>
A charging roll was prepared and evaluated in the same manner as in Example A1, except that the surface layer conductive agent of Example A1 was changed as follows.
-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot) 20 parts

<Comparative Example A2>
A charging roll was prepared and evaluated in the same manner as in Example A1, except that the surface layer conductive agent of Example A1 was changed as follows.
-Conductive agent (antimony-doped tin oxide, T-1: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 130 parts

[Example B]
<Example B1>
-Production of rubber composition-
A mixture having the following composition was kneaded with a 2.5 L kneader to obtain a rubber composition B1.
・ Rubber material 100 parts (Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, Hydrin T3106: manufactured by Nippon Zeon Co., Ltd.)
-Conductive agent (carbon black # 3030B: manufactured by Mitsubishi Chemical Corporation) 5 parts-Ionic conductive agent (benzyltrimethylammonium chloride, product name "BTEAC" Lion Specialty Chemicals) 1 part-Vulcanizing agent (organic sulfur, 4 , 4′-dithiodimorpholine, Balnock R: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.5 parts ・ Vulcanization accelerator A (thiazole type, di-2-benzothiazolyl disulfide, Noxeller DM-P: Ouchi 1.5 parts ・ Vulcanization accelerator B (thiuram, tetraethylthiuram disulfide, Noxeller TET-G: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.8 parts ・ Vulcanization accelerator (Zinc oxide) , Zinc oxide 1 type: manufactured by Shodo Chemical Co., Ltd.) 3 parts ・ Stearic acid 1.0 part ・ Heavy calcium carbonate 40 parts

-Production of elastic rolls-
After electroless nickel plating having a thickness of 5 μm, a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid was prepared.
The rubber composition B1 is extruded at a screw rotation of 25 rpm using a uniaxial rubber extruder having a cylinder inner diameter of 60 mm and L / D20, and the conductive support is continuously passed through a crosshead, thereby providing a conductive support. The rubber composition B1 was coated on the body. The temperature conditions of the extruder were set to 80 ° C. for all of the cylinder part, screw part, head part, and die part. The unvulcanized rubber roll formed of the conductive support and the coated rubber composition was vulcanized at 165 ° C. for 70 minutes in an air heating furnace to obtain an elastic roll B1 having a diameter of 12 mm.

-Formation of surface layer-
The following mixture was dispersed in a bead mill to obtain dispersion B1. This dispersion B1 was diluted with methanol, dip-coated on the surface of the elastic roll B1, and then heated and dried at 160 ° C. for 30 minutes to form a surface layer having a thickness of 10 μm, to obtain a charging roll B1.
・ Polymer material (N-methoxymethylated nylon, F30K: manufactured by Nagase ChemteX Corporation) 100 parts ・ Polymer material (polyvinyl butyral resin, ESREC BL-1: manufactured by Sekisui Chemical Co., Ltd.) 10 parts ・ Conducting agent (phosphorus doped type) Tin oxide particles, SP-2: manufactured by Mitsubishi Materials Denka Kasei Co., Ltd., particle shape: spherical, powder specific resistance 22.2 Ω · cm 20 parts • conductive agent (carbon black, MONARCH 1000: manufactured by Cabot) 5 parts • filler ( Polyamide resin, Orgasol 2001 DNat 1: Arkema) 20 parts ・ Catalyst (Nacure 4167: King Industry) 4 parts ・ Solvent (methanol) 700 parts ・ Solvent (butanol) 200 parts

  About the obtained charging roll B1, the physical-property measurement and evaluation test similar to Example A1 were performed. The results are shown in Table 2 below.

<Example B2>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 10 parts

<Example B3>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 15 parts

<Example B4>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 60 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 5 parts

<Example B5>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 60 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 10 parts

<Example B6>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical) 60 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 15 parts

<Example B7>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 100 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 5 parts

<Example B8>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical) 100 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 10 parts

<Example B9>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 100 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 15 parts

<Example B10>
In the evaluation test of Example B2, a charging roll was prepared and evaluated in the same manner as in Example B2, except that the electrophotographic photoreceptor 1 was changed to the electrophotographic photoreceptor 2 (charge transport layer thickness 34 μm). It was shown to.

<Comparative Example B1>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the type and amount of the conductive agent in the surface layer of Example B1 were changed as follows. The results are shown in Table 3.
-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot) 18 parts

<Comparative Example B2>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the type and amount of the conductive agent in the surface layer of Example B1 were changed as follows. The results are shown in Table 3.
-Conductive agent (antimony-doped tin oxide, T-1: manufactured by Mitsubishi Materials Electronics Chemical) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 10 parts

<Comparative Example B3>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the type and amount of the conductive agent in the surface layer of Example B1 were changed as follows. The results are shown in Table 3.
-Conductive agent (antimony-doped tin oxide, T-1: manufactured by Mitsubishi Materials Electronics Chemical) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 15 parts

[Example C]
<Example C1>
A charging roll was prepared and evaluated in the same manner as in Example A2 except that the surface layer filler in Example A2 was changed to no addition, and the results are shown in Table 4.

<Example C2>
A charging roll was prepared and evaluated in the same manner as in Example B2, except that the surface layer filler in Example B2 was not added, and the results are shown in Table 4.

<Comparative Example C1>
The charging roll was prepared and evaluated in the same manner as in Example B1, except that the type and amount of the conductive agent in the surface layer of Example B1 were changed as follows, and the filler in the surface layer was changed to no addition. Table 4 shows.
-Conductive agent (tin oxide, S-2000: manufactured by Mitsubishi Materials Electronics) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 15 parts

[Example D]
<Example D1>
-Production of rubber composition-
A rubber composition D1 was obtained by kneading a mixture having the following composition with a 2.5 L kneader.
・ Rubber material 100 parts (Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, Hydrin T3106: manufactured by Nippon Zeon Co., Ltd.)
-Conductive agent (carbon black # 3030B: manufactured by Mitsubishi Chemical Corporation) 5 parts-Ionic conductive agent (benzyltrimethylammonium chloride, trade name "BTEAC", manufactured by Lion Specialty Chemicals) 1 part-Vulcanizing agent (organic sulfur, 4,4'-dithiodimorpholine, Barnock R: manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1.5 parts ・ Vulcanization accelerator A (thiazole series, di-2-benzothiazolyl disulfide, Noxeller DM-P: large 1.5 parts ・ Vulcanization accelerator B (thiuram, tetraethylthiuram disulfide, Noxeller TET-G: made by Ouchi Shinsei Chemical Co., Ltd.) 1.8 parts ・ Vulcanization accelerator (oxidation) Zinc, zinc oxide 1 type: manufactured by Shodo Chemical Co., Ltd.) 3 parts ・ Stearic acid 1.0 part ・ Heavy calcium carbonate 40 parts

-Production of elastic rolls-
After electroless nickel plating having a thickness of 5 μm, a conductive support made of SUM23L having a diameter of 8 mm and subjected to hexavalent chromic acid was prepared.
The rubber composition D1 is extruded at a screw rotation of 25 rpm using a uniaxial rubber extruder with a cylinder inner diameter of 60 mm and L / D20, and the conductive support is continuously passed through a crosshead, thereby providing a conductive support. The rubber composition D1 was coated on the body. The temperature conditions of the extruder were set to 80 ° C. for all of the cylinder part, screw part, head part, and die part. The unvulcanized rubber roll formed of the conductive support and the coated rubber composition was vulcanized at 165 ° C. for 70 minutes in an air heating furnace to obtain an elastic roll D1 having a diameter of 12 mm.

-Formation of surface layer-
The following mixture was dispersed with a bead mill to obtain dispersion D1. The dispersion D1 was diluted with methanol, dip-coated on the surface of the elastic roll D1, and then heated and dried at 160 ° C. for 30 minutes to form a surface layer having a thickness of 10 μm, whereby a charging roll D1 was obtained.
・ Polymer material (N-methoxymethylated nylon, F30K: manufactured by Nagase ChemteX Corporation) 100 parts ・ Polymer material (polyvinyl butyral resin, ESREC BL-1: manufactured by Sekisui Chemical Co., Ltd.) 10 parts ・ Conducting agent (phosphorus doped type) Titanium oxide particles coated with tin oxide) 130 parts (W-4: Mitsubishi Materials Electronics Kasei Co., Ltd., primary particle diameter 10 nm, particle shape: spherical)
Filler (polyamide resin, Orgasol 2001 DNat1: Arkema) 20 parts Catalyst (Nacure 4167: King Industry) 4 parts Solvent (methanol) 700 parts Solvent (butanol) 200 parts

  About the obtained charging roll D1, the physical-property measurement and evaluation test similar to Example A1 were performed. The results are shown in Table 5 below.

<Example D2>
A charging roll was prepared and evaluated in the same manner as in Example D1 except that the conductive agent for the surface layer of Example D1 was changed as follows. The results are shown in Table 5.
-Conductive agent (titanium oxide particles coated with phosphorus-doped tin oxide, W-4: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 80 parts

<Example D3>
A charging roll was prepared and evaluated in the same manner as in Example D1 except that the conductive agent for the surface layer of Example D1 was changed as follows. The results are shown in Table 5.
-Conductive agent (titanium oxide particles coated with phosphorus-doped tin oxide, W-4: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 180 parts

<Example D4>
In the evaluation test of Example D1, a charging roll was prepared and evaluated in the same manner as in Example D1, except that the electrophotographic photosensitive member 1 was changed to the electrophotographic photosensitive member 2 (charge transport layer thickness 34 μm). It was shown to.

<Comparative Example D1>
A charging roll was prepared and evaluated in the same manner as in Example D1 except that the conductive agent for the surface layer of Example D1 was changed as follows. The results are shown in Table 5.
-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot) 20 parts

<Comparative Example D2>
A charging roll was prepared and evaluated in the same manner as in Example D1 except that the conductive agent for the surface layer of Example D1 was changed as follows. The results are shown in Table 5.
-Conductive agent (antimony-doped tin oxide, T-1: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 130 parts

[Example E]
<Example E1>
A charging roll was prepared and evaluated in the same manner as in Example D1, except that the surface layer filler of Example D1 was changed to no addition, and the results are shown in Table 6.

[Example F]
<Example F1>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 100 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot Corporation) 20 parts

<Example F2>
A charging roll was prepared and evaluated in the same manner as in Example B1, except that the amount of the conductive agent added to the surface layer of Example B1 was changed as follows.
-Conductive agent (phosphorus-doped tin oxide particles, SP-2: manufactured by Mitsubishi Materials Electronics Chemical) 20 parts-Conductive agent (carbon black, MONARCH1000: manufactured by Cabot) 0 parts

DESCRIPTION OF SYMBOLS 31 ... Electroconductive support, 32 ... Adhesive layer, 33 ... Elastic layer, 34 ... Intermediate | middle layer, 35 ... Surface layer, 200, 210, 220 ... Image forming apparatus, 206 ... Exposure apparatus, 207 ... Electrophotographic photoreceptor, 208 DESCRIPTION OF SYMBOLS ... Charging device, 209 ... Power source, 211 ... Developing device, 212 ... Transfer device, 213 ... Cleaning device, 214 ... Static eliminator, 215 ... Fixing device, 216 ... Mounting rail, 217 ... Opening for exposure, 218 ... Static elimination Opening for exposure, 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 Device, 405a to 405d ... Toner cartridge, 406 ... Drive roll, 407 ... Stretch roll, 408 ... Low back 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 (15)

A conductive support;
A surface layer disposed on the conductive support;
With
A charging member having a surface electron emission energy of 10 cps ^0.5 / eV or less.   The charging member according to claim 1, wherein the surface layer contains a conductive agent containing phosphorus-doped tin oxide.   The charging member according to claim 2, wherein the conductive agent containing phosphorus-doped tin oxide is at least one selected from phosphorus-doped tin oxide particles and conductive metal oxide particles coated with phosphorus-doped tin oxide.   The said surface layer contains resin, The content rate of the electrically conductive agent containing the said phosphorus dope type tin oxide in the said surface layer is 5 mass parts or more and 180 mass parts or less with respect to 100 mass parts of said resin. Item 4. The charging member according to Item 3.   The charging member according to claim 2, wherein the surface layer further contains carbon black. The surface layer contains a resin, and the content of the conductive agent containing the phosphorus-doped tin oxide in the surface layer is 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the resin.
The content ratio of the conductive agent containing phosphorus-doped tin oxide and the carbon black (conductive agent containing phosphorus-doped tin oxide: carbon black (mass ratio)) is 10:25 to 100: 5. Charging member.   The charging member according to claim 2, wherein the surface layer further contains a filler.   The charging member according to claim 1, which is used for charging by a direct current charging method.   A charging device comprising the charging member according to claim 1, wherein the charging member is charged by bringing the charging member into contact with a surface of a member to be charged. An image carrier,
And a charging device according to claim 9 for charging the image carrier.
A process cartridge attached to and detached from the image forming apparatus.   The process cartridge according to claim 10, wherein the image carrier is an electrophotographic photosensitive member having at least a surface layer having a charge transporting property of 25 μm or more on a substrate.   The process cartridge according to claim 10 or 11, wherein a rotation speed of the charging member is 100 mm / s or less. An image carrier,
The charging device according to claim 9, wherein the image holding body is charged.
A latent image forming apparatus for forming a latent image on the surface of the charged 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;
A transfer device for transferring the toner image formed on the surface of the image carrier to a recording medium;
An image forming apparatus comprising:   The image forming apparatus according to claim 13, wherein the image holding member is an electrophotographic photosensitive member having at least a surface layer having a charge transporting property of 25 μm or more on a substrate. The image forming apparatus according to claim 13, wherein a rotation speed of the charging member is 100 mm / s or less.