JPH07166052A - Polyurethane resin, electrostatically charging member, and electrophotographic apparatus - Google Patents

Abstract

PURPOSE:To obtain a conductive elastomer by mixing a specific solid electrolyte into a reaction product of a copolymer of and/or a mixture of polyether polyols with a mixture of aliph. and arom. diisocyanates. CONSTITUTION:A mixed prepolymer is obtd. by reacting a mixture of at least two polyether diols (e.g. polypropylene glycol and polytetramethylene glycol) with a mixture of arom. and aliph. diisocyanates (e.g. tolylene and hexamethylene diisocyanates). The prepolymer is mixed with about 0.05-30wt.% solid electrolyte of the formula (wherein R1 to R4 are each H, alkyl, or aryl) (e.g. a quaternary ammonium perchlorate) and further with a chain extender, a catalyst, etc., and is reaction molded, to give a conductive polyurethane elastomer with a desired shape and a low electric resistance. The elastomer is used for a member for electrostatically charging a photoreceptor in an electrophotographic apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyether type urethane resin, and more particularly to a urethane resin having a medium resistance such as antistatic property.

Further, the present invention relates to a charging member and an electrophotographic apparatus used in an electrophotographic apparatus, and more particularly to a contact charging member and an electrophotographic apparatus for pressing a charging device against an electrostatic latent image carrier such as a photoconductor to charge it. .

[0003]

2. Description of the Related Art Recently, polyurethane resins have been used in various products due to their good moldability and have been expanding the market.

However, the polyurethane resin is liable to be charged with static electricity, and therefore, it has been desired to develop a resin which has a low electric resistance and can easily conduct electricity. That is, when the polyurethane resin is charged with static electricity, dust and dirt are attached to the surface of the resin and it becomes dirty, or the resins stick to each other due to static electricity, which reduces work efficiency and reduces static electricity during processing of the resin. It was often inconvenient that sparks were generated by electrification.

For this reason, conventionally, development has been carried out to prevent electrification. As an example, there is a method in which a cationic or nonionic surfactant is added to the resin as an antistatic agent, but if the addition amount is not increased, the effect will not be obtained, the economy will be poor, and the binding strength will be weak. Therefore, it may fall out of the resin, and the composition of the resin may be changed, which is not practical.

There is also a method in which a conductive filler is dispersed in a resin, but this is also not preferable due to the problem of quantity, the problem of moldability and the like.

Further, there is also a method of spraying the above-mentioned surfactant or the like onto the resin after molding in a post-treatment, but the effect is not long lasting compared to the processing cost, the economical efficiency is lacked, and there is a problem that the surface is deteriorated. It was

Further, recently, a contact charging member for directly contacting and charging a photosensitive member has been proposed as described in, for example, Japanese Patent Laid-Open No. 63-167380, and compared with a conventionally used corona charging method. It has been recognized that it has advantages such as that a low applied voltage can be used and that ozone generation is small.

The conductivity is adjusted by adding a conductive substance such as conductive carbon black into the elastic layer. In order to improve the electric characteristics and the like, for example, JP-A-1-191161
No. 4.0x over the elastic layer as described in No.
A contact charging member has been proposed which is covered with a member having a volume resistance value of 10 ⁹ Ωcm or more.

In any case, the binder resin used for the elastic layer generally has a high resistance value of 10 ¹⁰ Ωcm or more,
It is difficult to stably lower the resistance value, and there are problems such as resistance fluctuation due to energization and resistance fluctuation due to molding conditions.

According to the studies by the inventors, it has been found that these problems are caused by the difference in resistance between the binder resin and the conductive pigment. It is considered that this is because when the difference in the specific resistance value between the binder resin and the conductive pigment is large, the electricity is concentrated in the pigment portion and easily deteriorates. Therefore, it is desired to develop an inexpensive resin in the medium resistance region.

Another method has been proposed in which an AC electric field and a DC electric field are applied together to obtain uniform charging. In contact charging in which an electric field in which an AC electric field is superimposed on a DC electric field is applied to the contact charging member for charging, mechanical vibration due to the AC electric field occurs in the charging member, which gives an unpleasant environment as a charging sound. There is. In particular, when the frequency of the alternating electric field is as high as several hundred Hz, it is recognized that the charging sound becomes remarkable due to the problem of tone color. When an AC electric field is applied to the charging member, this phenomenon is caused by vibration of the charging member due to the strength of the electric field and the vibration propagating to the photoconductor. At this time, when the support of the photoconductor is composed of a metal cylinder as is conventionally used, it is recognized that the propagated vibration causes resonance without being attenuated and a remarkable charging sound is generated. A charging member that can be charged only by the field is desired.

An object of the present invention is to provide a contact charging member that solves the above-mentioned drawbacks.

A further object of the present invention is to provide an elastic body that solves the above problems.

Another object of the present invention is to provide a urethane resin having a low specific resistance value.

A further object of the present invention is to provide a charging member that does not change its resistance value even when it is repeatedly energized.

Still another object of the present invention is to provide a charging member which can realize uniform charging only by a DC electric field.

Another object of the present invention is to provide an electrophotographic apparatus using these charging members.

[0019]

That is, the first aspect of the present invention is to provide a copolymer, a mixture, or a mixture and a mixture of two or more polyether polyols selected from dihydric alcohols, an aromatic diisocyanate, and A reaction product with a mixture of aliphatic diisocyanates and having the general formula (1)

[0020]

[Chemical 3] (In the formula, R ₁ to R ₄ represent a hydrogen atom, an alkyl group or an aryl group). A polyurethane resin containing a solid electrolyte.

Further, in a charging member which is brought into contact with a member to be charged and which is charged by applying a voltage, and which has at least a conductive elastic layer, the conductive elastic layer is selected from dihydric alcohols. A copolymer, a mixture, or a copolymer and a mixture of two or more polyether polyols,
A reaction product of a mixture of an aromatic diisocyanate and an aliphatic diisocyanate and having the general formula (1)

[0022]

[Chemical 4] (In the formula, R ₁ to R ₄ represent a hydrogen atom, an alkyl group or an aryl group) A charging member comprising a polyurethane resin containing a solid electrolyte.

Further, in an electrophotographic apparatus having a photoreceptor, a latent image forming means, a means for developing the formed latent image, and a means for transferring the developed image to a transfer material, the photoreceptor is charged as the latent image forming means. An electrophotographic apparatus characterized by using the above charging member for processing.

The first aspect of the present invention will be described below.

Examples of the polyol (PO) used in the present invention include an alkyl dihydric alcohol polymerized with an alkyl oxide such as ethylene oxide and propylene oxide as a monomer, and an aromatic dihydric alcohol such as bisphenol.

When the dihydric alcohol is polymerized, two or more kinds of monomers may be used as the PO of the present invention, or the PO of the present invention may be obtained by polymerizing the monomers independently and then mixing them. Further, PO synthesized alone may be mixed with the copolymer. It is preferable that one of these contains polyethylene oxide.

The isocyanate used in the present invention includes
Tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MD) as aromatic isocyanate
General-purpose isocyanates such as I) are mentioned. Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), hydrogenated MDI, hydrogenated xylylene diisocyanate (hydrogenated XDI), and other general-purpose isocyanates. In the present invention, two or more kinds of isocyanates are used in combination in order to improve mechanical properties and the like.

Polyurethane (PU) used in the present invention
As a method for synthesizing the above, PO and isocyanate may be reacted in advance as a prepolymer and then polymerized in two steps using a diamine, a chain extender or the like, or PO and isocyanate may be added in equal amounts to polymerize in one step. Good.

In the present invention, two or more prepolymers may be prepared and mixed in the polymerization stage. Thereby, the coexistence range of conductivity and elasticity can be further widened.

In the present invention, a quaternary ammonium salt of perchloric acid is used as the solid electrolyte. Quaternary ammonium is represented by the following formula.

[0031]

[Chemical 5] (In the formula, R ₁ to R ₄ represent a hydrogen atom, an alkyl group or an aryl group) The addition amount of the quaternary ammonium salt of perchloric acid used in the present invention is preferably 0.05 to 30% by weight. .
If the addition amount is less than 0.05% by weight, the effect of addition is small, and if it exceeds 30% by weight, workability and strength are deteriorated, which is not preferable.

In the present invention, a conductive pigment may be added to finely adjust the resistance value. Examples of the conductive pigment include carbon black, zinc oxide, titanium oxide, metal particles and the like.

Further, if necessary, known materials such as amine-based and organotin-based catalysts, crosslinking agents, stabilizers, foaming agents and the like may be added.

Further, for the purpose of improving the surface property of the charging member and improving the bleeding resistance, it is possible to coat the surface with a thin layer.

Examples of the electrophotographic apparatus used in the present invention include copying machines and LBPs.

The shape of the charging member used in the present invention is as follows.
It is possible to mention that the contact portion is uniform such as a cylindrical shape, a blade shape, and a block shape. It is preferably cylindrical due to durability and the like.

The photosensitive layer used in the present invention includes α-S
A photosensitive layer containing a commonly used photoconductor such as i, selenium, and OPC (organic photoconductor) can be used. In particular, an OPC photosensitive member is preferable because of the simplicity of the manufacturing method.

The OPC photoreceptor has a single layer type in which a charge generating (CG) material and a charge transporting (CT) material are mixed, or a laminated type in which a CG layer and a CT layer are laminated. In the case of a single-layer type photosensitive layer, a CG material and a CT material are dissolved and mixed in a suitable resin component using a solvent and the like, and the photosensitive layer is formed on the support by coating. In the case of a laminated type photosensitive layer, a CG layer and a CT layer are laminated in this order on a support, or C
The T layer and the CG layer may be laminated in this order, which is determined by the application.

Examples of the bias used in the present invention include a DC power supply and a DC + AC power supply. Specifically, in the case of a DC power supply, an electric field in which the charging start voltage is added to the desired charging voltage is applied. Further, the amount of change in resistance due to the environment may be finely adjusted by constant current control. In the case of a DC + AC power supply, an electric field in which a charging target voltage is superimposed on an AC having a peak-to-peak voltage that is at least twice the charging start voltage is applied.

The second aspect of the present invention is to react a copolymer, a mixture or a mixture of two or more polyether polyols selected from dihydric alcohols with a mixture of an aromatic diisocyanate and an aliphatic diisocyanate. It is a polyurethane resin characterized by being a product.

Further, in a charging member which is brought into contact with an object to be charged and which applies a voltage to charge the charging member having at least a conductive elastic layer, the conductive elastic layer is selected from dihydric alcohols. A copolymer, a mixture, or a copolymer and a mixture of two or more polyether polyols,
A charging member comprising a polyurethane resin which is a reaction product of a mixture of an aromatic diisocyanate and an aliphatic diisocyanate.

Further, in an electrophotographic apparatus having a photoconductor, a latent image forming means, a means for developing the formed latent image and a means for transferring the developed image to a transfer material, the photoconductor is charged as the latent image forming means. An electrophotographic apparatus characterized by using the above charging member for processing.

The second aspect of the present invention will be described below.

Examples of the polyol (PO) used in the present invention include alkyl dihydric alcohols obtained by polymerizing alkyl oxides such as ethylene oxide and propylene oxide as monomers, and aromatic dihydric alcohols such as bisphenol.

When the dihydric alcohol is polymerized, two or more kinds of monomers may be used as the PO of the present invention, or the PO of the present invention may be obtained by polymerizing the monomers independently and then mixing them. Further, PO synthesized alone may be mixed with the copolymer. It is preferable that one of these contains polyethylene oxide.

The isocyanate used in the present invention includes
Examples of aromatic isocyanates include general-purpose isocyanates such as TDI and MDI. Examples of the aliphatic isocyanate include general-purpose isocyanates such as HDI, hydrogenated MDI, hydrogenated XDI. The use of two or more isocyanates in the present invention is to improve mechanical properties.

Polyurethane (PU) used in the present invention
As a method for synthesizing the above, PO and isocyanate may be reacted in advance as a prepolymer and then polymerized in two steps using a diamine, a chain extender or the like, or PO and isocyanate may be added in equal amounts to polymerize in one step. Good.

In the present invention, two or more prepolymers may be prepared and mixed in the polymerization stage. This allows
The coexistence range of conductivity and elasticity can be further widened.

In the present invention, a conductive pigment may be added to finely adjust the resistance value. Examples of the conductive pigment include carbon black, zinc oxide, titanium oxide, metal particles and the like.

Further, if necessary, known materials such as amine-based and organotin-based catalysts, crosslinking agents, stabilizers, foaming agents and the like may be added.

Further, the surface of the charging member may be coated with a thin layer to improve the surface property, bleeding resistance and the like.

Examples of the electrophotographic apparatus used in the present invention include apparatuses such as a copying machine and LBP as shown in FIG. In FIG. 1, 1 is a member to be charged, 2 is a charging device, 3 is a document exposing device, 4 is a whole surface exposing device, 5 is a developing device, 6 is a transferring device, 7 is a cleaning device, 8 is a charging device power supply, and 9 is Document platen 10, lens 10 and fixing device 11 are omitted (other than main devices are omitted).

The shape of the charging member used in the present invention is as follows.
It is possible to mention that the contact portion is uniform such as a cylindrical shape, a blade shape, and a block shape. It is preferably cylindrical due to durability and the like.

The photosensitive layer used in the present invention includes α-S
A photosensitive layer containing a commonly used photoconductor such as i, selenium, and OPC (organic photoconductor) can be used. In particular, an OPC photosensitive member is preferable because of the simplicity of the manufacturing method.

The OPC photosensitive member may be of a single layer type in which a charge generating (CG) material and a charge transporting (CT) material are mixed, or a laminated type in which a CG layer and a CT layer are laminated. In the case of a single-layer type photosensitive layer, a CG material and a CT material are dissolved and mixed in an appropriate resin component using a solvent and the like, and the photosensitive layer is formed on the support by coating. In the case of a laminated type photosensitive layer, a CG layer and a CT layer are laminated in this order on a support, or C
The T layer and the CG layer may be laminated in this order, which is determined by the application.

The bias used in the present invention may be a DC power supply. Specifically, an electric field in which the charging start voltage is added to the desired charging voltage is applied. Further, the amount of change in resistance due to the environment may be finely adjusted by constant current control.

[0057]

EXAMPLES Specific examples will be shown below, but it is obvious that the examples are not limited thereto. First, an example of the first present invention will be described. Example 1 PPG (Mw: 1000) 1 mol. To TDI 2mo
l. To give Prepolymer 1. PTMG (M
w: 1000) 1 mol. To HDI 2 mol. To give Prepolymer 2. PEG (Mw: 1000)
1 mol. To TDI 2 mol. To give Prepolymer 3.

As a quaternary ammonium salt compound of perchloric acid, tetrabutylammonium perchlorate was added in an amount of 5% by weight and prepolymers 1, 2 and 3 each had 1 mol. And 1,4-butanediol as a chain extender 3 mol. Then, after adding the organotin catalyst, φ6 with an injection molding machine
Formed around a core metal of 3 mm to have a wall thickness of 3 mm,
A cylindrical molded product was obtained. When the specific resistance value was measured, it was 3 × 10 ⁶ Ωcm.

This is a laser beam printer LBPA
It was attached to the position of the charging device 404 (manufactured by Canon Inc.) and a bias was applied using the power supply of the main body.

Development V _DC -400V Drum surface potential -550V DC voltage -550V AC voltage 1.8KV _PP , f =
Image evaluation was performed by enduring 3000 sheets in a 150 Hz low temperature low humidity environment (15 ° C., 10%, hereinafter L / L) and a high temperature high humidity environment (32.5 ° C., 85%, hereinafter H / H).

As a result, there was no abnormal image in both L / L and H / H at the initial stage / after the endurance, and there was no problem.

Example 2 10 parts by weight of PPG (Mw: 1000) was terminated with PEG.
PO modified with 90 parts by weight of (Mw: 1000)
1 mol. Against TDI 2 mol. To give Prepolymer 1. PPG (Mw: 1000) 1 mol.
Against HDI 2 mol. To give Prepolymer 2.

The quaternary ammonium salt of perchloric acid was added in the same manner as in Example 1. Using these, a charging member was molded by the same method as in Example 1. When the specific resistance value was measured in a normal environment, it was 1 × 10 ⁶ Ωcm.

As a result, there was no problem in H / H at the initial stage and after the endurance test, and there was no problem. However, at L / L, a decrease in potential due to an increase in resistance due to environmental changes was observed.
However, no abnormalities on the image were observed.

Example 3 The charging member of Example 1 was attached to the position of the charging device of the copying machine FC310 (manufactured by Canon Inc.), and the bias was -12.
A DC electric field of 00 V was applied and image evaluation was performed.

As a result, no abnormal image was found at the initial stage in both L / L and H / H, and no abnormality due to durability was observed.

Example 4 Evaluations were made in the same manner as in Example 1 except that tetraheptyl ammonium perchlorate was used as the quaternary ammonium salt of perchloric acid and the addition amount was 30% by weight. Resistance value is 5 × 10
It was ⁴ Ωcm.

As a result, there was no abnormal image in the initial stage for both L / L and H / H, but the occurrence of minute cracks was recognized with the endurance. However, no abnormality was found on the image.

Example 5 Example 5 was repeated except that the amount of tetraheptylammonium perchlorate added was changed to 0.05% by weight. The resistance value was 5 × 10 ⁷ Ωcm.

As a result, no abnormality was found in H / H both in the initial stage and after the endurance, but in L / L, an increase in resistance was observed due to environmental changes and the influence of endurance, and a decrease in potential occurred. . However, no abnormalities were observed on the image.

Comparative Example 1 PPG and HDI were used except that Prepolymer 1 was used in Example 2.
The evaluation was performed in the same manner except that it was composed only. The resistance value was 5 × 10 ¹⁰ Ωcm, and the resistance was high for a charging device, and uniform charging could not be obtained.

As a result, both L / L and H / H were fogged on the image from the initial stage due to poor charging, and could not be used.

Comparative Example 2 Evaluation was carried out in the same manner as in Example 2, except that the HDI of the prepolymer 2 was changed to TDI and the isocyanate component of the prepolymers 1 and 2 was only TDI. Resistance value is 1 ×
It was 10 ⁹ Ωcm.

As a result, both L / L and H / H had no problem because there was no abnormal image at the initial stage, but in both environments, mechanical defects such as cracks occurred in the charging member due to durability, and especially in L / L. An image defect due to cracks occurred, and it could not be used.

Comparative Example 3 Evaluation was carried out in the same manner as in Example 1 except that the quaternary ammonium salt compound of perchloric acid was omitted. Resistance value is 1 x 1
It was 0 ¹⁰ Ωcm.

As a result, in L / L, an increase in resistance due to environmental changes was recognized, fog was generated from the initial stage, and it could not be used.

Next, an example of the second invention will be described. Example 6 PPG (Mw: 1000) 1 mol. To TDI 2mo
l. To give Prepolymer 1. PTMG (M
w: 1000) 1 mol. To HDI 2 mol. To give Prepolymer 2. PEG (Mw: 400) 1
mol. To TDI 2 mol. To react the prepolymer 3
And

Prepolymers 1, 2 and 3 each 1 mol. 1,4-butanediol 3 as a chain extender
mol. After adding the organotin catalyst, the mixture was molded by an injection molding machine so as to have a thickness of 3 mm around a core metal having a diameter of 6 mm to obtain a cylindrical molded product. When the specific resistance value was measured, it was 4 × 10 ⁹ Ωcm.

This is a laser beam printer LBPA
It was attached to the position of the charging device 404 (manufactured by Canon Inc.), and a DC electric field of -1300 V was applied as a bias. Image evaluation was performed by enduring 3000 sheets in a low temperature and low humidity environment (15 ° C., 10%) (hereinafter L / L) and a high temperature and high humidity environment (32.5 ° C., 85%) (hereinafter H / H).

As a result, both L / L and H / H had no abnormal image at the initial stage, and there was no problem. However, in L / L, a decrease in potential due to a slight increase in resistance was observed in the latter half of the durability test. However, no abnormalities on the image were observed.

Example 7 10 parts by weight of PPG (Mw: 1000) was terminated with PEG.
(Mw: 400) PO 1 modified with 90 parts by weight
mol. Against TDI 2 mol. To give Prepolymer 1. PPG (Mw: 1000) 1 mol. Against HDI 2 mol. To give Prepolymer 2.

Using these, a charging member was molded in the same manner as in Example 6. When the specific resistance value was measured in a normal environment, it was 1 × 10 ⁹ Ωcm.

As a result, there was no problem in the H / H at the initial stage / after the endurance and there was no problem, but at the L / L, a decrease in potential was observed along with an increase in the resistance value due to environmental changes. However, no abnormalities on the image were observed.

Example 8 Evaluations were made in the same manner as in Example 7, except that 2 parts by weight of conductive carbon black (Ketjen black) was added to the prepolymer 2 of Example 7. The resistance value was 5 × 10 ⁸ Ωcm.

As a result, no abnormal image was found at the initial stage in both L / L and H / H, and no abnormality associated with durability was observed.

Example 9 The charging member of Example 8 was attached to the position of the charging device of copying machine FC310 (manufactured by Canon Inc.), and a bias of −13 was applied.
A DC electric field of 00 V was applied and image evaluation was performed.

As a result, no abnormal image was found at the initial stage in both L / L and H / H, and no abnormality associated with durability was observed.

Comparative Example 4 PPG and HDI were used except that Prepolymer 1 was used in Example 7.
The evaluation was performed in the same manner except that it was composed only. The resistance value was 5 × 10 ¹² Ωcm, and the resistance was high for a charging device, and uniform charging could not be obtained.

As a result, in both L / L and H / H, fogging due to poor charging occurred on the image at the initial stage, and the image could not be used.

Comparative Example 5 Evaluations were made in the same manner as in Example 7, except that the HDI of the prepolymer 2 was changed to TDI and the isocyanate component of the prepolymers 1 and 2 was only TDI. Resistance value is 1 ×
It was 10 ⁹ Ωcm.

As a result, both L / L and H / H showed no abnormal images at the initial stage, and there was no problem. However, in both environments, mechanical defects such as cracks occurred in the charging member due to durability, and particularly in L / L. An image defect due to cracks occurred, and it could not be used.

[0092]

As described above, the polyurethane resins of the first and second aspects of the present invention have a resistance value in the medium resistance region.

Further, these polyurethane resins can be applied to a contact charging member for charging by charging the charging member with the photosensitive member and applying an electric field to the charging device.

Further, it is possible to satisfy both the resistance value and the mechanical characteristics such as hardness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus of the present invention.

Claims (6)

[Claims] 1. A reaction product of a copolymer, a mixture, or a copolymer and a mixture of two or more polyether polyols selected from dihydric alcohols, and a mixture of an aromatic diisocyanate and an aliphatic diisocyanate, And general formula (1) A polyurethane resin containing a solid electrolyte represented by the formula (wherein R ₁ to R ₄ represent a hydrogen atom, an alkyl group or an aryl group). 2. A charging member which contacts an object to be charged and applies a voltage to charge the charged member, which has at least a conductive elastic layer, wherein the conductive elastic layer is selected from dihydric alcohols. It is a reaction product of a copolymerization product, a mixture or a mixture and a mixture of two or more polyether polyols with a mixture of an aromatic diisocyanate and an aliphatic diisocyanate, and has the general formula (1) A charging member comprising a polyurethane resin containing a solid electrolyte represented by the formula (wherein R ₁ to R ₄ represent a hydrogen atom, an alkyl group or an aryl group). 3. An electrophotographic apparatus having a photoconductor, a latent image forming unit, a unit for developing the formed latent image, and a unit for transferring the developed image to a transfer material, wherein the photoconductor is charged as the latent image forming unit. An electrophotographic apparatus, wherein the charging member according to claim 2 is used for processing. 4. A reaction product of a copolymer, a mixture, or a copolymer and a mixture of two or more polyether polyols selected from dihydric alcohols, and a mixture of an aromatic diisocyanate and an aliphatic diisocyanate. Polyurethane resin characterized by. 5. A charging member that contacts an object to be charged and applies a voltage to charge the charged member, the charging member having at least a conductive elastic layer, wherein the conductive elastic layer is selected from dihydric alcohols. A polyurethane resin, which is a reaction product of a copolymer, a mixture, or a mixture and a mixture of two or more polyether polyols, and a mixture of an aromatic diisocyanate and an aliphatic diisocyanate. Charging member. 6. An electrophotographic apparatus having a photoconductor, a latent image forming means, a means for developing the formed latent image, and a means for transferring the developed image to a transfer material, wherein the photoconductor is charged as the latent image forming means. An electrophotographic apparatus, wherein the charging member according to claim 5 is used for processing.