JP2001166563A - Conductive member, process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain good electrifying characteristics over a long period of time by preventing electrifying failure due especially to an extreme rise in resistance or soiling when only DC voltage is utilized as applied voltage. SOLUTION: In a conductive member, a processing cartridge provided with the conductive member and an image forming device, the conductive member is provided with a supporting body 2a and a coating layer 2c on the supporting body 2a and is installed in contact to an electrophotographic photoreceptor, the conductive member where the voltage is applied contains a conductive agent, of which the surface of the covering layer is surface-treated and the surface of the conductive member has a coefficient of static friction of <=1.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact member such as a charging member, a developer carrying member, a transfer member, a cleaning member, and a charge removing member in an electrophotographic image forming apparatus such as a printer, a facsimile, and a copying machine. And a process cartridge and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, a charging process in an electrophotographic process is performed by applying a high voltage (DC voltage of 6 to 8 k) to a metal wire.
A corona charger that uniformly charges a surface of an electrophotographic photosensitive member, which is a member to be charged, to a predetermined polarity and potential by a corona shower generated by applying V) has been widely used. However, there are problems such as requiring a high-voltage power supply and generating a relatively large amount of ozone.

On the other hand, a contact charging system in which a voltage is applied while a conductive member is in contact with a photosensitive member to charge the surface of the photosensitive member has been put to practical use. In this method, a conductive member (charging member) as a charge supply member such as a roller type, a blade type, a brush type, and a magnetic brush type is brought into contact with the photoreceptor, and a predetermined charging bias is applied to the contact charging member to expose the photosensitive member. The body surface is uniformly charged to a predetermined polarity and potential.

[0004] This charging system has the advantages of lowering the voltage of the power supply and generating less ozone. Among them, a roller charging method using a conductive roller (charging roller) as a contact charging member is preferably used from the viewpoint of charging stability. However, the charging uniformity is somewhat disadvantageous as compared with the corona charger.

In order to improve the charging uniformity, Japanese Patent Application Laid-Open
As disclosed in Japanese Patent Application Laid-Open No. 149669, the charging start voltage (V) is changed to a DC voltage corresponding to a desired surface potential Vd of the member to be charged.
_TH ) AC voltage component (A) having a peak-to-peak voltage of twice or more
An “AC charging method” is used in which a voltage (pulsating voltage; a voltage whose voltage value changes periodically with time) superimposed on the C voltage component is applied to the contact charging member. This is for the purpose of the leveling effect of the potential by the AC voltage, and the potential of the member to be charged converges to the potential Vd, which is the center of the peak of the AC voltage, and is not affected by disturbances such as the environment. This is an excellent method as a contact charging method.

However, in order to superimpose a high AC voltage which is a peak-to-peak voltage which is twice or more the discharge starting voltage (V _TH ) when a DC voltage is applied, an AC power supply is required separately from the DC power supply, and the apparatus itself is required. This leads to higher costs. Furthermore, there is a problem that the durability of the charging roller and the photoreceptor is easily reduced by consuming a large amount of the alternating current.

[0007] These problems can be solved by applying only a DC voltage to the charging roller to perform charging. However, if only a DC voltage is applied to the charging roller, the following problems are likely to occur.

[0008]

When only a DC voltage is applied to the above-mentioned conventional charging member, the charging member is deteriorated by continuous use, particularly in a low humidity environment, and the resistance of the charging member is likely to increase (charge-up). Along with this, there is a problem that the charged potential of the surface of the charged member subjected to the charging treatment is reduced.

When a plurality of continuous images are output by an image forming apparatus using, for example, a reversal developing method, using a conventional charging roller having such a problem, a plurality of continuous images are output after the initial image is output. Has a problem that the image quality is deteriorated.

[0010] To solve this problem, a technique of reducing the resistance change of the charging member due to oxidation of the conductive agent by oxygen or moisture by incorporating a silane-coupled conductive agent into the surface layer of the charging member has been proposed. JP Hei 10
-254217.

However, this publication does not disclose a low-humidity environment, and a conductive member having a smaller resistance change has been desired.

Further, in an image forming apparatus using a contact charging system, there is a tendency that unevenness in image density or the like occurs due to poor charging due to contamination of the charging member (adhesion of the surface of the developer), thereby causing a problem in durability. There is an urgent need to prevent the influence of poor charging due to dirt on the prints to enable printing of a plurality of sheets. In particular, in the case of a DC charging system in which only a DC voltage is applied to the charging member, the influence of contamination on the charging member is reduced by AC.
As compared with the charging system, the image tends to appear as an image defect.

The object of the present invention has been made in view of the above, and even when a charging process is performed on a member to be charged by applying only a DC voltage to the charging member, the resistance of the conductive member does not easily increase. Another object of the present invention is to provide a conductive member capable of maintaining good charging characteristics for a long period of time, a process cartridge and an image forming apparatus using the same.

Another object of the present invention is to provide a conductive member capable of maintaining good charging characteristics for a long period without causing charging failure due to contamination of the conductive member, a process cartridge using the same, and an image. An object of the present invention is to provide a forming apparatus.

[0015]

That is, the present invention relates to a conductive member having a support and a coating layer on the support, wherein the conductive member is disposed in contact with an electrophotographic photosensitive member and is applied with a voltage. A conductive member, wherein the coating layer contains a surface-treated conductive agent, and the surface of the conductive member has a static friction coefficient of 1.0 or less.

According to another aspect of the present invention, there is provided a process cartridge which integrally supports an electrophotographic photosensitive member and the above-described conductive member, and is detachable from an image forming apparatus main body.

Further, the present invention is an image forming apparatus comprising an electrophotographic photosensitive member, a charging unit having the above-mentioned conductive member, an exposing unit, a developing unit and a transferring unit.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the use of a specific conductive agent and the setting of the surface static friction coefficient to a specific value act synergistically to not only suppress the resistance change of the conductive member but also to reduce the resistance change. In addition, dirt hardly adheres to the surface of the conductive member, and poor charging due to dirt on the charging member does not occur, and a very excellent image can be obtained. In particular, as shown in FIG. 1, a plurality of sheets of an image forming apparatus employing a so-called developing and cleaning (cleanerless) system in which a developing unit does not have a developing and independent cleaning unit and collects toner remaining on a photoreceptor after transfer by a developing unit. It is extremely effective in enabling printing.

Although the mechanism of the present invention has not been clarified, the following has been elucidated through intensive studies by the present inventors.

First, when the surface layer is formed by coating,
Hydrophobizing the conductive agent contained in the surface layer increases the affinity with the paint solvent, improves the dispersibility of the conductive agent, improves the surface properties of the coating film, affects the coefficient of static friction, and causes contamination. Has been found to be advantageous for the adhesion of

It has also been found that the resistance change during continuous use of the conductive member depends at least on the surface state (hydrophilicity, hydrophobicity) of the conductive agent. For example, it has been found that when a hydrophilic conductive agent is contained in the conductive member, the resistance is likely to increase due to continuous use of the conductive member. Particularly, in a low-temperature and low-humidity environment, the resistance of the conductive member greatly increases. Then, in this low-temperature and low-humidity environment, it has been found that it is effective to use a hydrophobized conductive agent as a conductive agent for the conductive member in order to reduce a rise in resistance due to continuous use of the conductive member.

Although the mechanism of the increase in resistance during continuous use of the conductive member is not clear, the increase in resistance that occurs when a hydrophilic conductive agent is contained in the surface layer causes polarization or the like of the hydrophilic group on the surface of the conductive agent due to conduction. Wake up, charge up,
It is thought that the conductive function as a conductive agent may be lost.

In particular, in a low-temperature and low-humidity environment, it is considered that water is not present around the hydrophilic group, so that it is likely to be affected by energization. Therefore, it is conceivable that the charge-up portion can be reduced by crushing the hydrophilic group by performing the hydrophobic treatment, so that the resistance does not increase even if the charging member is used continuously (continuous energization).

According to the various studies described above, it has been determined that the surface layer of the conductive member contains a hydrophobized conductive agent and that the static friction coefficient of the surface of the conductive member is 1.0 or less. The charging member of the present invention is excellent in charging stability / durability.

Next, the schematic structure of the image forming apparatus of the present invention will be described.

(1) Image Forming Apparatus FIG. 1 is a schematic structural view of an example of an image forming apparatus provided with the process cartridge of the present invention. The image forming apparatus of the present embodiment is a reversal developing system using a transfer type electrophotography, and a developing and cleaning system (cleanerless).

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member as an image bearing member, which is rotated at a predetermined peripheral speed (process speed) in the direction of an arrow.

Reference numeral 2 denotes a charging roller (conductive member of the present invention) as charging means for the electrophotographic photosensitive member, which is brought into contact with the electrophotographic photosensitive member 1 with a predetermined pressing force. In this embodiment, the charging roller is driven. Rotates at the same speed as the electrophotographic photosensitive member 1. A predetermined DC voltage (in this case, -1300 V) is applied to the charging roller 2 from a charging bias application power source S1 to cause the surface of the electrophotographic photosensitive member 1 to have a predetermined polarity potential (dark portion potential -700V). ) Uniform contact charging method / DC
It is charged by a charging method.

Reference numeral 3 denotes an exposure unit, for example, a laser beam scanner. Exposure L corresponding to the target image information is performed on the charged surface of the electrophotographic photoreceptor 1 by the exposure unit 3 so that the surface potential of the electrophotographic photoreceptor is set to the potential of the exposed light portion (the potential of the light portion -120 V). ) Is selectively reduced (attenuated) to form an electrostatic latent image.

Reference numeral 4 denotes a reversal developing means, which is a toner (negative toner) charged in the exposed portion of the electrostatic latent image on the electrophotographic photosensitive member to the same polarity as that of the electrophotographic photosensitive member (developing bias -350 V). ) Is selectively adhered to visualize the electrostatic latent image as a toner image. In the figure, 4a is a developing roller, 4a
b denotes a toner supply roller, and 4c denotes a toner layer thickness regulating member.

Reference numeral 5 denotes a transfer roller as transfer means.
A transfer portion is formed by contacting the electrophotographic photosensitive member 1 with a predetermined pressing force, and rotates at a peripheral speed substantially equal to a rotational peripheral speed of the electrophotographic photosensitive member in a forward direction with the rotation of the electrophotographic photosensitive member.
Further, a transfer voltage having a polarity opposite to the charge polarity of the toner is applied from the transfer bias application power source S2. The transfer material P is fed to the transfer unit from a paper feed mechanism (not shown) at a predetermined control timing, and the back surface of the fed transfer material P is charged by the transfer roller 5 to which a transfer voltage is applied. The toner image on the electrophotographic photoreceptor 1 is electrostatically transferred to the transfer material P at the transfer portion by being charged to the opposite polarity.

The transfer material to which the toner image has been transferred in the transfer section is separated from the electrophotographic photosensitive member, introduced into a toner image fixing means (not shown), subjected to a toner image fixing process, and output as an image formed product. Is done. In the case of the double-sided image forming mode or the multiple image forming mode, this image-formed product is introduced into a recirculation transport mechanism (not shown) and is re-introduced into the transfer section.

Residues on the electrophotographic photosensitive member such as transfer residual toner are charged to the same polarity as the charging polarity of the electrophotographic photosensitive member by the charging roller 2. And the transfer residual toner is
The light passes through the exposure unit to the developing means 4 and is electrically collected in the developing device by the back contrast, thereby achieving development and cleaning (cleanerless).

In this embodiment, the electrophotographic photosensitive member 1, the charging roller 2, and the developing means 4 are integrally supported, and the process cartridge 6 is detachable from the image forming apparatus main body. At this time, the developing means 4 may be provided separately.

(2) Conductive member For example, the charging member is in the form of a roller as shown in FIG. 2, and has a conductive support 2a and a coating layer, and an elastic layer 2b integrally formed on the outer periphery thereof and a coating of the elastic layer. It is composed of a surface layer 2c formed on the outer periphery.

FIG. 3 shows another configuration of the charging member of the present invention. As shown in FIG. 3, the charging member may be a three-layer structure including an elastic layer 2b, a resistance layer 2d and a surface layer 2c, or a second resistance layer 2e provided between the resistance layer 2d and the surface layer 2c. Alternatively, a configuration in which four or more layers are formed as a coating layer on the conductive support 2a may be employed.

The conductive support 2a used in the present invention comprises:
Round bars of metal materials such as iron, copper, stainless steel, aluminum and nickel can be used. Further, these metal surfaces may be subjected to plating treatment for the purpose of rust prevention and imparting scratch resistance, but it is necessary that the conductivity is not impaired.

In the charging roller 2, the elastic layer 2b has appropriate conductivity and elasticity to supply power to the electrophotographic photosensitive member as a member to be charged and to ensure good uniform adhesion to the electrophotographic photosensitive member 1. I have. Also, charging roller 2
In order to ensure uniform adhesion of the electrophotographic photoreceptor 1 and the electrophotographic photoreceptor 1, it is preferable that the elastic layer 2b is formed by polishing so that the central portion is thickest at the center and becomes thinner toward both ends, that is, a so-called crown shape. A commonly used charging roller 2
However, since a predetermined pressing force is applied to both ends of the support 2a to make contact with the electrophotographic photosensitive member 1, the pressing force at the central portion is small, and the pressing force at the both ends is large. There is no problem if the straightness is sufficient, but if it is not sufficient, density unevenness may occur in the images corresponding to the center and both ends. The crown shape is formed to prevent this.

The conductivity of the elastic layer 2b is such that a conductive agent having an electronic conduction mechanism such as carbon black, graphite and a conductive metal oxide and an ion such as an alkali metal salt and a quaternary ammonium salt are contained in an elastic material such as rubber. It is preferable to adjust to less than 10 ¹⁰ Ωcm by appropriately adding a conductive agent having a conductive mechanism. As a specific elastic material of the elastic layer 2b, for example, natural rubber, ethylene propylene rubber (EP
DM), synthetic rubbers such as styrene butadiene rubber (SBR), silicone rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR), nitrile butadiene rubber (NBR) and chloroprene rubber (CR), and polyamide. Resins, polyurethane resins and silicone resins are also included.

In order to achieve charging uniformity, a charging member for charging a member to be charged by applying only a DC voltage is preferably made of a medium-resistance polar rubber (for example, epichlorohydrin rubber, NBR, CR and urethane). It is preferable to use rubber or the like) or a polyurethane resin as the elastic material. These polar rubbers and polyurethane resins are considered to have a small amount of conductivity due to moisture and impurities in the rubber or resin serving as carriers, and it is considered that these conductive mechanisms are ionic conduction. However, an elastic layer was formed without adding any conductive agent to these polar rubbers or polyurethane resins, and the obtained charging member had a resistance value of 10 ¹⁰ Ωcm or more in a low-temperature and low-humidity environment (L / L). Therefore, a high voltage must be applied to the charging member.

Therefore, the above-mentioned conductive agent having an electronic conductive mechanism or the conductive agent having an ionic conductive mechanism is appropriately added and adjusted so that the resistance value of the charging member becomes less than 10 ¹⁰ Ωcm in an L / L environment. Is preferred. However, a conductive agent having an ionic conduction mechanism has a small effect of lowering the resistance value, and particularly has a small effect in an L / L environment. Therefore, the resistance may be adjusted by supplementarily adding a conductive agent having an electronic conductive mechanism together with adding a conductive agent having an ionic conductive mechanism. However, when the elastic layer is a surface layer, the conductive agent needs to be surface-treated.

The elastic layer 2b may be a foam obtained by foaming and molding these elastic materials.

Since the resistance layer 2d (e) is formed at a position in contact with the elastic layer, it is provided for the purpose of preventing bleed-out of the softening oil, plasticizer, etc. contained in the elastic layer to the surface of the charging member. Provided for the purpose of adjusting the electric resistance of the entire charging member.

Examples of the material constituting the resistance layer used in the present invention include epichlorohydrin rubber, NBR, polyolefin-based thermoplastic elastomer, urethane-based thermoplastic elastomer, polystyrene-based thermoplastic elastomer, fluororubber-based thermoplastic elastomer, and polyester-based thermoplastic elastomer. Examples thereof include thermoplastic elastomers, polyamide thermoplastic elastomers, polybutadiene thermoplastic elastomers, ethylene vinyl acetate thermoplastic elastomers, polyvinyl chloride thermoplastic elastomers, and chlorinated polyethylene thermoplastic elastomers. These materials may be used alone or as a mixture of two or more kinds, and may be a copolymer.

The resistance layer 2d (e) used in the present invention needs to have conductivity or semi-conductivity. Conductivity,
In order to develop semiconductivity, conductive agents having various electron conduction mechanisms (conductive carbon, graphite, conductive metal oxide, copper, aluminum, nickel, iron powder, alkali metal salts, ammonium salts, etc.) or ions A conductive agent can be used as appropriate. In this case, in order to obtain a desired electric resistance, two or more of the above-mentioned various conductive agents may be used in combination. It is particularly preferable that the resistance layer 2d (e) of the present invention contains a surface-treated conductive agent, and when the resistance layer is a surface layer, it is necessary that the surface-treated conductive agent be used. .

In the present invention, the surface of the conductive member has a coefficient of static friction of 1.0 or less, preferably 0.01 or more, and particularly preferably 0.5 or less. If the coefficient of static friction exceeds 1.0, the releasability of the surface of the conductive member is reduced, so that the transfer residual toner is liable to be attached, which causes deterioration of image quality. In particular, in a low-temperature and low-humidity environment, it tends to cause deterioration of image quality. If the ratio is less than 0.1, the electrophotographic photosensitive member and the conductive member are likely to slip, which undesirably affects rotational driving. The coefficient of static friction depends not only on the type and mixing ratio of the materials used for the surface layer, but also on the mixing state of the materials. In the present invention, it is important that the coefficient of static friction satisfies the above range. Is not particularly limited. However, it is preferable to use a binder resin having a static friction coefficient of 0.50 or less.

Hereinafter, the static friction coefficient of the surface of the conductive member is represented by μs.
And the coefficient of static friction of the binder resin in the surface layer is μs _B.

In the present invention, the measurement of the static friction coefficient μs _B of the binder resin in the selection of the material of the surface layer is performed by forming the binder resin as a coating film on an aluminum sheet, obtaining a sample sheet, and measuring the static friction coefficient; HEIDON Tribogear Muse TYPE: 941 "Shinto Kagaku Co., Ltd."
The static friction coefficient μs _B of the binder resin material on the surface layer of the charging member was determined.

The material having a static friction coefficient μs _B of 0.50 or less obtained by this measuring method contains a conductive agent and other additives to form a surface layer of the conductive member. Further, the material of the conductive member is designed so that the surface of the conductive member has a static friction coefficient μs of 1.0 or less.

FIG. 5 schematically shows the measurement of the coefficient of static friction μs on the surface of the conductive member according to the present invention. This measurement method is a method suitable for the case where the object to be measured is in the form of a roller, and is a method according to the Euler belt system. According to this method, the object comes into contact with the conductive member as the object at a predetermined angle (θ). One end of the belt (thickness: 20 μm, width: 30 mm, length: 180 mm) is connected to the measurement unit (load meter), and the other end is connected to the weight W. In this state, when the conductive member is rotated at a predetermined direction and speed, when the force measured by the measuring unit is F (g) and the weight of the weight is W (g), the friction coefficient (μ) is Μ = (1 / θ) In (F / W) An example of a chart obtained by this measurement method is shown in FIG. Here, it can be seen that the value immediately after rotating the conductive member is the force required to start the rotation, and the value after that is the force required to continue the rotation. (Time = 0 seconds) can be referred to as a static friction force, and a force at an arbitrary time of 0 <t (sec) ≦ 60 can be referred to as a dynamic friction force at an arbitrary time. Therefore, the coefficient of static friction: μs = (1 / θ) In (F _{<
t = 0>} / W).

In this measuring method, the surface of the belt (the surface that comes into contact with the conductive member) is made of a predetermined material (for example, the outermost layer of the photoreceptor, one coated with a developer by an appropriate means, or a standard material such as stainless steel). By doing so, the coefficient of friction for various substances can be determined. In other words, it is more preferable to adjust the material of the contact surface, the rotation speed, the load, etc. to the process conditions of the actual machine, but it is necessary to measure the friction coefficient between the conductive member and the photoconductor and the friction coefficient between the conductive member and stainless steel. As a result of conducting a comparative study, it was found that the friction coefficient for stainless steel may be used. That is, it is roughly represented by the coefficient of friction K between the conductive member and the photosensitive member × the coefficient of friction between the conductive member and stainless steel. Here, K is a numerical value determined by the material and state of the photoreceptor surface, and is a substantially constant value if the photoreceptor material and surface state are the same, but changes if they are slightly different.

Therefore, it is desirable that the material type, the compounding ratio thereof, the production conditions, the surface physical properties, and the like match the actual system as much as possible. However, this requires a great deal of complexity and, as described above, the conductive member. In the present invention, for the sake of simplicity, the coefficient of friction between the stainless steel and the surface of the stainless steel is determined by the ten-point average roughness, since the friction coefficient between the stainless steel and the photosensitive member and the friction coefficient between the conductive member and the stainless steel tend to have regularity. (Rz) is 5 μm or less｝, rotation speed is 100 rpm, and load is 50 g.
It measured on condition of.

As a result of our intensive studies, when the surface of the conductive member has the above physical properties (μs ≦ 1.0),
Since toner hardly adheres to the surface of the charging roller, uniform charging can be performed even when the total number of printed sheets increases, and fogging on an image does not occur. It was also found that even in a low-temperature and low-humidity environment where image fogging easily occurs due to toner adhesion, image fogging does not occur even when the total number of printed sheets increases. If the coefficient of static friction μs exceeds 1.0, the releasability of the surface of the charging member becomes small, so that the transfer residual toner tends to adhere, which may cause deterioration of image quality. In particular, in a low-temperature and low-humidity environment, it tends to cause deterioration of image quality.
Note that the lower limit of the static friction coefficient μs is preferably 0.01 or more in terms of roller slippage and the like.

Further, the surface layer 2c constitutes the surface of the charging member, and should not be made of a material that is in contact with the photoreceptor to be charged and contaminates the photoreceptor.

Surface layer 2 for exhibiting the characteristics of the present invention
Examples of the binder resin material of c include fluorine resin, polyamide resin, acrylic resin, polyurethane resin, silicone resin, butyral resin, styrene-ethylene / butylene-
An olefin copolymer (SEBC) and an olefin-ethylene-butylene-olefin copolymer (CEBC) are exemplified. As the material of the surface layer in the present invention, a fluororesin, an acrylic resin, a silicone resin and the like are particularly preferable.

For the purpose of reducing the coefficient of static friction to these binder resins, a solid lubricant such as graphite, mica, molybdenum disulfide and a fluororesin powder, a fluorine-based surfactant, a wax, and a silicone oil are added. May be.

For the surface layer, various conductive agents (conductive carbon, graphite, copper, aluminum, nickel, iron powder, and conductive metal oxides such as conductive tin oxide and titanium oxide) are appropriately used. In the present invention, in order to obtain a desired electric resistance, two or more of the above-mentioned various conductive agents may be used in combination. The particle size of the conductive agent is 0.001 to 1.
It is preferably 0 μm. Average particle size 0.001μ
If it is less than m, the conductive agents are likely to agglomerate, making the surface treatment difficult or uneven in the surface treatment, making it difficult to perform uniform treatment. If the thickness exceeds 1.0 μm, the surface roughness of the charging member is easily affected, which is not preferable.

The ratio between the conductive agent and the binder resin is preferably 0.1: 1.0 to 2.0: 1.0 by mass. If the conductive agent is less than 0.1, it is difficult to obtain the effect of including the conductive agent, and if it exceeds 2.0, the mechanical strength of the surface layer decreases, the layer becomes brittle, and the hardness increases. , Tend to lose flexibility.

In the present invention, the conductive agent for the surface layer comprises a surface treatment,
Preferably, it is characterized by being subjected to a hydrophobic treatment. As the hydrophobizing agent, a coupling agent (a central element such as silicon, titanium, aluminum and zirconium is not particularly selected), an oil, a varnish, and an organic compound are preferable. Particularly, an alkoxysilane coupling agent and a fluoroalkylalkoxysilane coupling agent are preferable.

As a method of making the conductive agent hydrophobic, for example, in the case of a silane coupling agent, there are two methods, a dry method and a wet method.

(A) Dry method A silane coupling agent is sprayed or blown in a vapor state while thoroughly stirring a conductive agent. Heat treatment is added if necessary.

(B) Wet method A conductive agent is dispersed in a solvent, and a silane coupling agent is also diluted with water or an organic solvent, and added in a slurry state with vigorous stirring. This method is preferred for uniform processing. Further, there are the following three specific methods as the silane pretreatment of the conductive agent surface.

Aqueous solution method About 0.1 to 0.5% of silane is injected and dissolved in water of constant pH or water-solvent with sufficient stirring, and hydrolyzed. After immersing the filler in this solution, it is filtered or squeezed to remove water to some extent, and then at 120 to 130 ° C.
Dry thoroughly.

Organic Solvent Method Silane is dissolved in a small amount of water and an organic solvent (alcohol, benzene, halogenated hydrocarbon) containing a hydrolysis solvent (hydrochloric acid, acetic acid). After the filler is immersed in this solution, it is filtered or pressed to remove the solvent, and is sufficiently dried at 120 to 130 ° C.

Spraying method An aqueous solution of silane or a solvent solution is sprayed while vigorously stirring the filler. Then 120-130 ° C
Dry thoroughly.

The degree of hydrophobicity of the conductive agent is 20 to 98%
Is particularly preferable, and 30 to 70% is particularly preferable. When the degree of hydrophobicity is less than 20%, when the charging member is continuously used in a low-temperature and low-humidity environment, the resistance rises to a level at which a problem becomes a problem, and the charging potential on the surface of the member to be charged tends to decrease. Further, when the degree of hydrophobicity exceeds 98%, it becomes difficult to control the function (conductivity) as a conductive agent, and it becomes easy for the pigment to coagulate strongly.

The resistance value of the surface layer is 10 ⁴ to 10 ¹⁵ Ωcm.
It is preferred that Further, the thickness is preferably 1 to 500 μm. In particular, the thickness is preferably 1 to 50 μm.

In the present invention, the ten-point average surface roughness Rz (JIS B0601) of the conductive member is 10 μm.
The following is preferred.

When the conductive member (charging roller) of the present invention is used, if the surface of the conductive member is rough, uneven charging on the surface may cause slight charging unevenness, resulting in poor image quality. Alternatively, the photoconductor surface may be eroded (e.g., scraped). Recently, since a developer (toner) having a size of several μm is generally used,
If the surface roughness of the conductive member exceeds 10 μm, the developer may enter the recesses on the surface and cause contamination of the conductive member surface. Therefore, it is preferable that the surface of the conductive member is smoother. Specifically, the ten-point average surface roughness Rz is 10 μm.
m or less, more preferably 4 μm or less.

The degree of hydrophobicity of the conductive agent is set in the above range (2).
(0 to 98%), the ten-point average surface roughness (Rz) of the conductive member could be relatively easily reduced.

On the other hand, when a conductive agent having a degree of hydrophobicity of less than 20% is used, Rz may vary depending on the measurement location, or the maximum height Rmax may become a large value. It is considered that this may be caused by poor affinity between the solvent and the pigment and poor dispersibility when preparing a paint for forming the surface layer because the degree of hydrophobicity of the pigment is low.

When a conductive agent having a degree of hydrophobicity of more than 98% is used, very fine irregularities such as noise tend to be generated on the roughness curve on the chart when the surface roughness of the conductive member is measured. And the ten-point average surface roughness (Rz) tended to be a relatively large value. It is thought that this is because the conductive agent is re-agglomerated in the paint dispersing step for forming the surface layer due to strong aggregation of the conductive agent, resulting in poor dispersion.

(3) Electrophotographic Photoreceptor The electrophotographic photoreceptor used in the present invention is not particularly limited.

[0074]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1) A charging roller as a charging member of the present invention was prepared in the following manner. Epichlorohydrin rubber 100 parts by mass Quaternary ammonium salt 2 parts by mass Calcium carbonate 30 parts by mass Zinc oxide 5 parts by mass Fatty acid 5 parts by mass The above materials were adjusted to 10 by a closed mixer adjusted to 60 ° C.
After kneading for 15 minutes, 15 parts by mass of an ether ester plasticizer was added to 100 parts by mass of epichlorohydrin rubber,
The mixture was further kneaded with a closed mixer cooled to 20 ° C. for 20 minutes to prepare a raw material compound. To this compound was added 1 part by mass of sulfur as a vulcanizing agent, 1 part by mass of Noxerer DM as a vulcanization accelerator and 0.5 part by mass of Noxerer TS with 100 parts by mass of epichlorohydrin rubber as a raw rubber, and cooled to 20 ° C. The mixture was kneaded with a roll machine for 10 minutes. The obtained compound is molded by an extruder so as to form a roller around a support made of stainless steel having a diameter of 6 mm, and then subjected to heat vulcanization molding, followed by polishing treatment so as to have an outer diameter of 12 mm to obtain an elastic layer. Was.

A surface layer as shown below was formed on the elastic layer by coating. As a material of the surface layer 2c, 5 parts by mass of isocyanate (HDI) and 100 parts by mass of a mixed solution of acrylic polyol in toluene / methyl ethyl ketone (MEK) (solid content: 10% by mass) and a conductive agent subjected to hydrophobic treatment as a conductive agent are used. Tin oxide particles (number average particle size 0.03μ
m) Using a paint (parts by mass of conductive agent / parts by mass of binder resin (P / B) = 0.8 / 1.0) to which 8 parts by mass was added, coating was performed by a dipping method to form a film. A 10 μm surface layer was coated to form a roller-shaped charging member.

Ethyltrimethoxysilane was used as a hydrophobizing agent for the conductive tin oxide. The organic solvent method described above was selected as the method for making the filler hydrophobic.

[Measurement of Hydrophobicity of Conductive Agent] In order to evaluate the hydrophobicity of the conductive agent, the hydrophobicity was measured using methanol as follows. 0.2 g of fine particles (in the case of Example 1, tin oxide) is added to 50 ml of water in an Erlenmeyer flask.
Methanol is titrated from the burette. At this time, the solution in the flask is constantly stirred with a magnetic stirrer.
The end of settling of the microparticles is confirmed by the total amount suspended in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water at the end of settling. The degree of hydrophobicity of the conductive tin oxide measured by the above method was 62%.

[Measurement of Static Friction Coefficient μs _B of Surface Layer Material]
The same binder resin as that on which the surface layer was formed was made into a paint, and the clear paint was coated on an aluminum sheet to obtain a sample sheet for measuring a coefficient of static friction (μs _B ).

The static friction coefficient of the sample sheet was measured as follows:
Static friction coefficient measuring device: HEIDON Tribogear Muse TYPE: 941 "manufactured by Shinto Kagaku Co., Ltd." The coefficient of static friction μs _B was an average value obtained by measuring five arbitrary points on the sample sheet. The coefficient of static friction of the binder resin of the surface layer in this example was 0.26.

[Measurement of Static Friction Coefficient μs on Charging Roller Surface] As described above, when the static friction coefficient μs was measured using the measuring device shown in FIG. 5, the static friction coefficient μs on the charging roller surface of the present embodiment was found to be 0.36.

The ten-point average surface roughness (R
z) was 2.9 μm.

"When only DC voltage is applied to the charging roller
Endurance test for producing multiple continuous images of an image "
Attach the charging roller obtained above to the image forming apparatus of the formula
Environment 1 (temperature 23 ° C./humidity 55%), environment 2 (temperature
Temperature 32.5 ° C / 80% humidity) and environment 3 (temperature 15 ° C /
A4 image with a printing rate of 4% in each environment of 10% humidity)
Performs image output of 15,000 images continuously, and every 500 images
Print a halftone image and increase the resistance of the charging roller
Visual evaluation of image defects caused by image
Was done. Table 1 shows the results. However, for electrophotographic photoreceptors
Dark section potential V _DHas -700V at the beginning of the image output durability test
Set the printing voltage (DC voltage only) in each environment
An image output durability test was performed.

In the table, ◎ indicates that the obtained image is very good,
Is good, △ is slightly uneven density in halftone image, ×
Indicates that the halftone image has density unevenness and density roughness.

The resistance of the charging roller was measured by the method shown in FIG. 4 before starting the image output durability test (initial stage) and immediately after outputting 15,000 continuous images. Table 1 shows the results. In the figure, 2 is a conductive member, 11
Denotes a cylindrical electrode made of stainless steel, 12 denotes a resistor, and 13 denotes a recorder. The pressing force between them is the same as that of the image forming apparatus used, and the resistance value when -250 V is applied from the external power supply S3 is measured.

"Evaluation of Image Fogging Due to Adhesion of Toner on Charging Roller" The charging roller obtained above was mounted on an electrophotographic image forming apparatus similar to that used in the above evaluation, and the environment 1 (temperature of 23 ° C. / Under the respective environments of humidity 55%), environment 2 (temperature 32.5 ° C./humidity 80%), and environment 3 (temperature 15 ° C./humidity 10%), an image endurance test was performed on a plurality of sheets. By visually observing the obtained image, the toner was attached to the charging roller, and the occurrence of fog on the printing paper due to the toner was evaluated. Specifically, a plurality of A4 images with a printing rate of 4% are output,
A solid white image and a halftone image were printed every 500 sheets, and evaluated visually. Table 2 shows the results.

In the table, ◎ indicates that the obtained image is very good,
Is good, △ is fog in halftone image,
X indicates that there is fog in the halftone image and the solid white image.

As a result, a good image was obtained from the beginning in all environments, and an image which was almost the same as the initial image was obtained even after 15,000 images were output.

(Example 2) A charging roller as a charging member of the present invention was prepared in the following manner. NBR 100 parts by weight Quaternary ammonium salt 3 parts by weight Ester plasticizer 25 parts by weight Calcium carbonate 30 parts by weight Zinc oxide 5 parts by weight Fatty acid 2 parts by weight The above materials were adjusted by a closed mixer adjusted to 60 ° C. 10
After kneading for 20 minutes, the mixture was further kneaded with a closed mixer cooled to 20 ° C. for 20 minutes to prepare a raw material compound. To this compound, 1 part by mass of sulfur as a vulcanizing agent and 3 parts by mass of Noxeller TS as a vulcanization accelerator were added to 100 parts by mass of NBR of raw rubber, and kneaded for 10 minutes by a two-roll machine cooled to 20 ° C. The obtained compound is
A 6 mm stainless steel support is molded around the support with an extruder so as to form a roller, and then heated and vulcanized.
The elastic layer was obtained by performing a polishing treatment so as to have a thickness of 12 mm.

On the above elastic layer, a surface layer as shown below was formed by coating. Using polyvinyl butyral resin as a material for the surface layer 2c, 45 parts by mass of conductive titanium oxide (number average particle size 0.1 μm) subjected to hydrophobic treatment with respect to 100 parts by mass of the ethanol solution (solid content 50% by mass). Was applied by a dipping method using a paint (P / B = 0.9 / 1.0) to which a surface layer having a thickness of 3 μm was coated to obtain a roller-shaped charging member.

In this example, i-butyltrimethoxysilane was used as the hydrophobizing agent. The above-mentioned aqueous solution method was selected as the hydrophobic treatment method. Further, as a result of measuring the degree of hydrophobicity of the conductive titanium oxide of this example by the above-described method, the degree of hydrophobicity was 20%.

The same binder resin as that used to form the surface layer was formed into a paint, and the clear paint was used to coat an aluminum sheet to obtain a sample sheet for measuring the coefficient of static friction. Static friction coefficient μs of the binder resin of the surface layer of this embodiment
_B was 0.34.

The static friction coefficient μ of the surface of the charging roller of this embodiment
s was measured by a method as shown in FIG.
It was 2. The ten-point average surface roughness (Rz) of the charging roller surface was 1.8 μm.

This charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

(Example 3) A charging roller as a charging member of the present invention was prepared in the following manner. Epichlorohydrin rubber 100 parts by mass Quaternary ammonium salt 1 part by mass Conductive carbon black 10 parts by mass Calcium carbonate 30 parts by mass Zinc oxide 5 parts by mass Fatty acid 2 parts by mass The above materials were adjusted by a closed mixer adjusted to 60 ° C. 10
After kneading for 15 minutes, 15 parts by mass of an ether ester plasticizer was added to 100 parts by mass of epichlorohydrin rubber,
The mixture was further kneaded with a closed mixer cooled to 20 ° C. for 20 minutes to prepare a raw material compound. To this compound was added 1 part by mass of sulfur as a vulcanizing agent, 1 part by mass of Noxerer DM as a vulcanization accelerator and 0.5 part by mass of Noxerer TS with 100 parts by mass of epichlorohydrin rubber as a raw rubber, and cooled to 20 ° C. The mixture was kneaded with a roll machine for 10 minutes. The obtained compound was molded in a roller shape around a φ6 mm stainless steel support by an extruder, and was heated and vulcanized.
The elastic layer was obtained by performing a polishing treatment so as to form a crown shape having a diameter of 11.9 mm and both ends of φ11.9 mm.

On the above elastic layer, a resistance layer as shown below was formed by coating. As a material of the resistance layer 2c, 100 parts by mass of epichlorohydrin rubber was dispersed and dissolved in a toluene solvent to prepare a coating for the resistance layer. This paint was applied onto the elastic layer 2b by dipping to form a 100 μm-thick resistive layer 2d.

Further, a surface layer 2c shown below was formed by coating on the resistance layer 2d. As a material of the surface layer 2c, a fluororesin copolymer obtained by copolymerizing fluoroolefin (tetrafluoride type), hydroxyalkyl vinyl ether and vinyl carboxylate is used.
Using a paint obtained by adding 5 parts by mass of isocyanate (HDI) and 40 parts by mass of a conductive tin oxide (number average particle diameter 0.03 μm) subjected to a hydrophobic treatment to 00 parts by mass (solid content: 50% by mass). , Applied by dipping method to a film thickness of 5 μm
To form a roller-shaped charging member.

In the examples, n-hexyltrimethoxysilane was used as the hydrophobizing agent. The above-mentioned organic solvent method was selected as the hydrophobic treatment method. The degree of hydrophobicity of the conductive tin oxide of this example was 30%.

The same binder resin as that used to form the surface layer was formed into a paint, and the clear paint was coated on an aluminum sheet to obtain a surface layer sample sheet for measuring a static friction coefficient. The static friction coefficient μs _B of the binder resin of the surface layer of the present example was 0.12.

The coefficient of static friction μs of the surface of the charging roller of this embodiment was 0.23. The ten-point average surface roughness (Rz) of the charging roller surface was 2.5 μm.

This charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

Example 4 Instead of ethyltrimethoxysilane as a hydrophobizing agent, methyltrimethoxysilane and fluoroalkylalkoxysilane @ CF ₃ CH ₂ C
A charging roller was prepared and evaluated in the same manner as in Example 1, except that H ₂ Si (OCH ₃ ) ₃ } was used (mass ratio 1: 1). The results are shown in Tables 1 and 2. The degree of hydrophobicity of the conductive tin oxide of this example was 80%.

Further, the static friction coefficient μs _B of the binder resin of the surface layer of this embodiment was 0.14, and the static friction coefficient μs of the surface of the charging roller was 0.24. The ten-point average surface roughness (Rz) of the charging roller surface was 2.5 μm.

Example 5 A charging roller was prepared and evaluated in the same manner as in Example 4, except that titanium oxide (number average particle diameter: 0.1 μm) was used instead of tin oxide as a conductive agent. . The results are shown in Tables 1 and 2. The degree of hydrophobicity of the conductive titanium oxide of this example was 98%.

Further, the static friction coefficient μs _B of the binder resin of the surface layer of this embodiment was 0.17, and the static friction coefficient μs of the charging roller surface was 0.27. The ten-point average surface roughness (Rz) of the charging roller surface was 2.2 μm.

Comparative Example 1 A charging roller was prepared by the following method. EPDM 100 parts by mass Conductive carbon black 30 parts by mass Zinc oxide 5 parts by mass fatty acid 2 parts by mass
After kneading for 15 minutes, 15 parts by mass of paraffin oil was added to 100 parts by mass of EPDM, and the mixture was further kneaded with a closed mixer cooled to 20 ° C. for 20 minutes to prepare a raw material compound. The compound rubber EPDM100
0.5 parts by mass of sulfur as a vulcanizing agent and MBT (mercaptobenzothiazole) 1 as a vulcanization accelerator with respect to parts by mass
2 parts by mass, 1 part by mass of TMTD (tetramethylthiuram disulfide) and 1.5 parts by mass of ZnMDC (zinc dimethyl dithiocarbamate) were added, and the mixture was cooled to 20 ° C.
The mixture was kneaded with this roll machine for 10 minutes. The obtained compound was placed around a φ6 mm stainless steel support with an outer diameter of φ12.
An elastic layer was obtained by heat vulcanization molding using a press molding machine so as to form a roller having a diameter of 2 mm.

A resistance layer as shown below was formed on the elastic layer by coating. As a material of the resistance layer 2d, 100 parts by weight of a polyurethane resin and 15 parts by weight of a conductive carbon black are dispersed and dissolved in a methyl ethyl ketone (MEK) solvent to prepare a coating for the resistance layer. This paint is applied on the elastic layer 2b by dipping to form a resistive layer 2 having a thickness of 100 μm.
d was coated.

Further, a surface layer 2c shown below was formed on the resistance layer 2d by coating. As a material for the surface layer 2c, 100 parts by mass of a polyamide resin, 10 parts by mass of conductive tin oxide (untreated hydrophobized, number average particle size 0.03 μm) are dispersed and dissolved in a mixed solvent of methanol / toluene to prepare a coating for the surface layer. create. Using this paint, a surface layer having a thickness of 5 μm was formed by coating by a dipping method to obtain a roller-shaped charging member. In addition, the hydrophobicity of the conductive tin oxide of Comparative Example 1 was 0%.

The same binder resin as that used to form the surface layer was formed into a paint, and the clear paint was used to coat an aluminum sheet to obtain a sample sheet of the surface layer for measuring the coefficient of static friction. The static friction coefficient μs _B of the binder resin of the surface layer of Comparative Example 1 was 0.71.

The coefficient of static friction μs of the charging roller surface is 1.0
It was 3. The ten-point average surface roughness (Rz) of the charging roller surface was 7.9 μm.

The charging roller was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

When an image forming apparatus using this charging roller was used to perform an image forming durability test on a plurality of sheets, it was found that an image defect due to an increase in resistance of the charging member in a low-temperature and low-humidity environment (temperature 15 ° C./humidity 10%). Had occurred. Further, in the durability test for image output on a plurality of sheets, unevenness in image density due to toner adhesion occurred.

(Example 6) As a material of the surface layer 2c, 100 parts by mass of a polyurethane elastomer and 60 parts by mass of tin oxide (number average particle diameter 0.03 μm) subjected to hydrophobic treatment were used.
A charging roller was prepared in the same manner as in Comparative Example 1 except that methyl ethyl ketone (MEK) was used as a solvent.

In this example, a titanium coupling agent (isopropoxytitanium tristearate: TTS) was used as the hydrophobizing agent. The hydrophobization treatment was performed as follows. That is, tin oxide and TTS were dispersed in a toluene solvent, and the solvent was removed by stirring while heating to 70 to 80 ° C, and then sufficiently dried at 120 to 130 ° C.

The static friction coefficient μs _B of the binder resin of the surface layer was 0.70, and the static friction coefficient μs of the charging roller surface was 0.99. The ten-point average surface roughness (Rz) of the charging roller surface was 8.5 μm.

This charging roller was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

When an image forming apparatus using this charging roller was used to carry out an image forming durability test on a plurality of sheets, an image defect due to an increase in resistance of the charging member in a low-temperature and low-humidity environment (temperature 15 ° C./humidity 10%). Had occurred. In addition, image fogging caused by toner adhesion occurred in a multiple-sheet image output durability test.

(Example 7) A charging roller was prepared by the following method. NBR 100 parts by mass Lithium perchlorate 5 parts by mass Calcium carbonate 30 parts by mass Zinc oxide 5 parts by mass Fatty acid 2 parts by mass The above materials were adjusted to 10 by a closed mixer adjusted to 60 ° C.
After kneading for 100 minutes, DOS
(Dioctyl sebacate) 20 parts by mass of a plasticizer were added, and 2
Kneaded for another 20 minutes in a closed mixer cooled to 0 ° C,
A raw material compound was prepared. In this compound, sulfur 1 as a vulcanizing agent was added to 100 parts by mass of NBR of raw rubber.
3 parts by mass of Noxeller TS as a vulcanization accelerator were added, and the mixture was kneaded with a two-roll mill cooled to 20 ° C. for 10 minutes. The obtained compound was molded by an extrusion molding machine so as to form a roller around a φ6 mm stainless steel support, heated and vulcanized, and then polished to an outer diameter of 12 mm to obtain an elastic layer. .

A surface layer as shown below was formed on the elastic layer by coating. As a material of the surface layer 2c, a polyurethane elastomer 100 parts by mass Hydrophobized conductive tin oxide (number average particle size 0.03 μm) 40 parts by mass is dispersed and dissolved in a xylene / methyl isobutyl ketone (MIBK) solvent to form the surface layer 2c. Create paint for paint. Using this paint, a surface layer having a thickness of 10 μm was formed by coating by a dipping method to obtain a roller-shaped charging member.

In this example, ethoxysilane was used as the hydrophobizing agent. Further, as the hydrophobic treatment method,
The organic solvent method described above was selected. The degree of hydrophobicity of the conductive tin oxide was 99%.

The static friction coefficient μs _B of the binder resin of the surface layer was 0.64, and the static friction coefficient μs of the charging roller surface was 0.90. The ten-point average surface roughness (Rz) of the charging roller surface was 5.9 μm.

The charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2. Images output by an image forming apparatus using this charging roller include:
From the beginning, the halftone image was rough.

Example 8 For the purpose of reducing the coefficient of static friction, 0.5 parts by mass of silicone oil was added to the surface layer of the charging roller, and as a conductive agent, oxidation treatment was performed in the same manner as in Example 3 so that the hydrophobicity was treated. A charging roller was prepared in the same manner as in Comparative Example 1, except that tin (number average particle diameter: 0.03 μm) was used. The degree of hydrophobicity of the conductive tin oxide of this example was 30%.
Met.

The static friction coefficient μs _B of the binder resin of the surface layer of this embodiment was 0.71, and the static friction coefficient μs of the charging roller surface was 0.89. The ten-point average surface roughness (Rz) of the charging roller surface was 6.2 μm.

This charging roller was evaluated in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

Comparative Example 2 A charging roller was prepared and evaluated in the same manner as in Example 2 except that the surface layer was made of non-hydrophobized titanium oxide and the film thickness was changed to 40 μm. The results are shown in Tables 1 and 2.

The degree of hydrophobicity of the conductive agent was 0%, the static friction coefficient of the surface of the charging roller was 0.55, and the ten-point average surface roughness (Rz) was 2.8 μm.

Comparative Example 3 A charging roller was prepared and evaluated in the same manner as in Example 8, except that the silicone oil used for the surface layer was not used. The results are shown in Tables 1 and 2.

The degree of hydrophobicity of the conductive agent is 30%.
The static friction coefficient of the surface of the charging roller was 1.07, and the ten-point average surface roughness (Rz) was 6.6 μm.

[0130]

[Table 1]

[0131]

[Table 2]

[0132]

As described above, according to the present invention, since toner adherence to the surface of the charging roller is small, image fog and image density unevenness caused by toner adherence do not occur.
As a result, the total number of printed sheets of the image forming apparatus is greatly increased, and the durability stability is improved. Further, even in a low-temperature and low-humidity environment, image fogging caused by toner adhesion does not occur. In addition, in a charging member in which only a DC voltage is applied to the charging member to perform a charging process on the member to be charged by a contact charging method, there is almost no increase in resistance (charge-up) during continuous use of the charging member, so that the charging member is stably applied over a long period of time. The charged potential on the surface of the charged body is obtained. Therefore, by using the conductive member of the present invention in an image forming apparatus, high image quality can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus including a process cartridge of the present invention.

FIG. 2 is a schematic sectional view of a conductive member of the present invention.

FIG. 3 is a schematic sectional view of a conductive member of the present invention.

FIG. 4 is a schematic view of a device for measuring the resistance of a conductive member.

FIG. 5 is a schematic view of a static friction coefficient measuring device for a conductive member.

FIG. 6 is an example of a chart obtained when measurement is performed using a static friction coefficient measuring device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/16 103 G03G 15/16 103 21/10 21/00 312 21/06 340

Claims (15)

[Claims] 1. A conductive member having a support and a coating layer on the support, wherein the conductive member is placed in contact with an electrophotographic photosensitive member and a voltage is applied to the conductive member. A conductive member comprising an agent and a surface of the conductive member having a static friction coefficient of 1.0 or less. 2. The conductive member according to claim 1, wherein the applied voltage is a DC voltage only. 3. The method according to claim 1, wherein the coating layer is a surface layer.
The conductive member as described in the above. 4. The conductive member according to claim 3, wherein the conductive member has an elastic layer and a surface layer on the elastic layer. 5. The conductive member according to claim 1, which has a static friction coefficient of 0.01 or more. 6. The static friction coefficient is 0.5 or less.
6. The conductive member according to any one of claims 1 to 5. 7. The conductive agent whose surface has been treated is 0.001 to 0.001.
The conductive member according to claim 1, having a number average particle size of 1.0 μm. 8. The coating layer contains a surface-treated conductive agent and a binder resin, and the ratio of the conductive agent to the binder resin is 0.1: 1.0 to 2.0: 1. 8. The method according to claim 1, wherein the value is 0.
The conductive member according to any one of the above. 9. The conductive member according to claim 1, wherein the surface treatment is a hydrophobic treatment. 10. The conductive member according to claim 9, wherein the hydrophobic treatment is a treatment with a coupling agent. 11. The conductive member according to claim 9, wherein a degree of hydrophobicity obtained by the hydrophobic treatment is 20 to 98%. 12. The conductive member has a ten-point average surface roughness of 10 μm.
The conductive member according to any one of claims 1 to 11, which has the following surface roughness. 13. The conductive member according to claim 1, wherein the conductive member is a charging member. 14. An electrophotographic photosensitive member and an electrophotographic photosensitive member according to claim 1.
A process cartridge integrally supporting the conductive member according to any one of the above, and being detachably attached to an image forming apparatus main body. 15. An image forming apparatus comprising: an electrophotographic photosensitive member; a charging unit having the charging member according to claim 1; an exposing unit; a developing unit; and a transfer unit.