JP2966900B2 - Charging member - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a charging member, and more particularly to a charging member used for primary charging, transfer charging, and charge removal in electrophotography.

[Conventional technology]

The charging process in the electrophotographic process using the electrophotographic photoreceptor has almost always involved a high voltage (DC)
(5-8 kV) is applied and charging is performed by the corona generated. However, in this method, ozone and NO
There have been problems such as deterioration of the surface of the photoreceptor due to corona products such as _x, causing image blurring and deterioration, and contamination of the wire affecting image quality, resulting in image white spots and black stripes. On the other hand, the electric current directed to the photoreceptor is 5 to 30
%, Most of which flowed to the shield plate and was ineffective as a charging means.

In order to compensate for such disadvantages, direct charging methods have been studied and many proposals have been made (JP-A-57-178267, JP-A-56-104351, JP-A-58-40566, JP-A-58-40566). -139156, JP-A-58-150975, etc.). However, even if the photoconductor is charged by the contact charging method as described above, each portion of the photoconductor surface is not uniformly charged,
Spot-like uneven charging occurs. For example, in the reversal development method, even if a process of light image exposure or less is applied to the photosensitive member in the spot-like uneven charging state, the output image becomes a spot-like black spot image corresponding to the spot-like charging unevenness, and the regular developing method uses the spot-like black spot image. The image becomes a spot-like white spot image with respect to unevenness, and a high-quality image cannot be obtained.

Further, the direct charging method has no market record in spite of many proposals. The reasons for this include the uniformity of charging and the occurrence of discharge breakdown of the photoconductor due to the direct application of voltage. One breakdown point due to discharge breakdown, for example, in the case of a cylindrical photosensitive member, has a drawback that charging in the entire axial direction flows to the breakdown point and the charge is no longer charged.

[Problems to be solved by the invention]

A method of forming a resin layer on the surface to prevent this dielectric breakdown has also been reported. However, these materials also have large fluctuations in resistance under low temperature and low humidity, and their chargeability is unstable. The resin on the surface of the photoconductor and the resin on the surface of the charging member were compatible with each other and had defects such as sticking.

Accordingly, an object of the present invention is to solve the above-mentioned drawbacks and to provide a spot-like fog due to non-uniform charging, and to stably supply a high-quality image free from image defects and the like due to discharge breakdown of a photoconductor. It is to provide a member.

[Means for solving the problem]

That is, the present invention provides a charging member having a conductive elastic layer on a conductive support, wherein polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer or butadiene-butene copolymer is formed on the conductive elastic layer. A charging member having a resin layer containing the coalesced particles.

 Hereinafter, the present invention will be described in more detail.

In the charging member of the present invention, as shown in FIG. 1, a conductive elastic layer 2 is provided on a conductive support 1a, and a resin layer 3 containing a butadiene-based polymer is further provided on the elastic layer 2. The basic configuration is to adopt a three-layer configuration as described above.

In the present invention, as the butadiene-based polymer, a homopolymer of butadiene, and a copolymer of a butadiene-styrene copolymer, a butadiene-acrylonitrile copolymer, and a copolymer with a monomer capable of butadiene-butene copolymer are used. Can be

 Further, a binder resin may be added to the resin layer.

However, the addition amount of the binder resin is preferably 30% by weight or less based on the total resin. Examples of the binder resin in the resin layer include acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, polyvinyl butyral, polyvinyl acetal, polyarylate, polycarbonate, phenoxy resin, polyvinyl acetate, polyvinyl pyridine and the like.

Because the surface of the conventional charging member was made of rubber or polyurethane, if it is kept in contact with the electrophotographic photoreceptor, the photoreceptor and the charging member are fixed or wrinkles are generated when the surface is hard, Image defects occurred.

On the other hand, the charging member having the resin layer containing the butadiene-based polymer of the present invention has low adhesion to the electrophotographic photoreceptor, and has high flexibility, so that a high-quality image is provided, and toner smear is also reduced. It can be used as a stable charging member with little change in volume resistance of the resin layer even under low temperature and low humidity.

The thickness of the resin layer is preferably in the range of 5 to 500 μm, particularly preferably in the range of 20 to 200 μm.

The elastic layer 2 may be made of a metal such as aluminum, iron, copper, or the like, a conductive polymer such as polyacetylene, polypyrrole, or polythiophene, or a rubber or plastic elastomer obtained by dispersing a conductive material by dispersing carbon, metal, or the like. Those laminated with metal or another conductive substance can be used. Further, the elastic layer 2 may have a multilayer structure in which functions are separated as necessary. Iron, copper, stainless steel, or the like can be used as the conductive support 1a.

Further, as shown in FIG. 2, a protective layer 4 may be provided on the surface of the charging member to protect the charging member. This protective layer is formed of a resin layer, and may be mixed with conductive particles therein to control conductivity and insoluble resin powder 5 to control surface roughness of the charging member.

In the case of a blade-shaped charging member as shown in FIG. 3, a conductive elastic layer 2 is provided on a conductive sheet metal 1b, and a resin layer 3
Is provided.

 Further, a protective layer may be provided.

The shape of the charging member may be any of a roller shape and a blade shape, but is preferably a roller shape in terms of uniform charging.

The electrophotographic photoreceptor is based on a configuration in which a photosensitive layer is provided on a conductive support. As the conductive support, a support having conductivity itself, for example, aluminum, an aluminum alloy, stainless steel, chromium, titanium, or the like can be used.In addition, aluminum, an aluminum alloy, an indium oxide-tin oxide alloy, or the like can be used. A conductive support having a layer formed by vacuum deposition, plastic, a support in which conductive particles (eg, carbon black, tin oxide particles, etc.) are impregnated with a suitable binder into plastic or paper, and a conductive binder. Plastic or the like can be used.

An undercoat layer having a barrier function and an adhesive function may be provided between the conductive support and the photosensitive layer. The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane, gelatin, aluminum oxide, or the like. The thickness of the undercoat layer is 5 μm or less, preferably 0.5 to 3 μm.
m is appropriate. The undercoat layer preferably has a resistivity of 10 ⁷ Ω · cm or more in order to exhibit its function.

The photosensitive layer is formed, for example, by coating a photoconductor such as an organic photoconductor, amorphous silicon, or selenium with a binder as necessary, and then forming the coating or vacuum deposition. When an organic photoconductor is used, a photosensitive layer composed of a combination of a charge generation layer that generates charge carriers upon exposure and a charge transport layer capable of transporting the generated charge carriers can also be used effectively.

The charge generation layer is formed by depositing one or more kinds of charge generation materials such as azo pigments, quinone pigments, quinone anine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, and quinacdrine pigments, or It can be formed by dispersing together with a binder (even without a binder) and coating.

The binder can be selected from a wide range of insulating resins or organic photoconductive polymers. For example, as the insulating resin, polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, acrylic resin, polyacrylamide resin, polyamide, cellulose resin, urethane resin, epoxy resin, Casein, polyvinyl alcohol and the like can be mentioned. Examples of the organic photoconductive polymer include carbazole, polyvinyl anthracene, and polyvinyl pyrene.

The thickness of the charge generation layer is 0.01 to 15 μm, preferably 0.05 to
5 μm, and the weight ratio between the charge generation layer and the binder is 10: 1 to
1:20.

The solvent used for the coating for the charge generation layer is selected from the solubility and dispersion stability of the resin and the charge transporting material used. As the organic solvent, alcohols, sulfoxides, ethers, esters, and aliphatic halides are used. Hydrocarbons or aromatic compounds can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a Meyer bar coating method, and a blade coating method.

The charge transport layer is formed by dissolving a charge transport material in a film-forming resin. Examples of the organic charge transporting material used in the present invention include hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials can be used alone or in combination of two or more.

Examples of the binder used for the charge transport layer include phenoxy resin, polyacrylamide, polyvinyl butyral, polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenolic resin, epoxy Resin, polyester, alkyd resin, polycarbonate,
Polyurethane or a copolymer containing two or more of the repeating units of these resins, for example, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, and a styrene-maleic acid copolymer can be given. In addition, organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene can be selected.

The thickness of the charge transport layer is 5 to 50 μm, preferably 8 to 20 μm.
m, and the weight ratio of the charge transport material to the binder is 5: 1 to 1:
5, preferably about 3: 1 to 1: 3. The coating can be performed by the coating method as described above.

Furthermore, since dyes, pigments, organic charge transporting substances, and the like are generally vulnerable to contamination by ultraviolet rays, ozone, oil, and the like, metals, and the like, a protective layer may be provided as necessary. To form an electrostatic latent image on this protective layer, the surface resistivity must be 10 ¹¹ Ω
It is desirable that it is above.

The protective layer of the photoconductor is made of a resin such as polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer. A solution dissolved by a solvent can be formed on the photosensitive layer by coating and drying. At this time, the thickness of the protective layer is generally in the range of 0.05 to 20 μm. The protective layer may contain an ultraviolet absorber or the like.

The charging member of the present invention can be applied to, for example, an electrophotographic apparatus as shown in FIG. In this apparatus, a primary charging member 6, an image exposure unit 7, a developing unit 8, a corona charger 9 for transfer charging, a cleaning unit 10, and a pre-exposure unit 11 are arranged on a peripheral surface of an electrophotographic photosensitive member 12. .

A voltage (for example, a pulsating voltage in which a DC voltage of 200 V or more and 2000 V or less and an AC voltage of 4000 V or less between peaks are superimposed) is externally applied to the primary charging member 6 which is arranged in contact with the electrophotographic photosensitive member 12. Then, the surface of the electrophotographic photosensitive member 12 is charged, and the image on the original is image-exposed to the photosensitive member by the image exposure means 7 to form an electrostatic latent image. Next, the electrostatic latent image on the photoconductor is developed (visualized) by adhering the developer in the developing means 8 to the photoconductor, and the developer on the photoconductor is transferred to a corona charger for charging. The developer is transferred to a transfer member 13 such as paper by 9, and the developer remaining on the photoconductor without being transferred to the paper at the time of transfer by the cleaning unit 10 is collected.

Although an image can be formed by such an electrophotographic process, if residual charges remain on the photoreceptor, light is applied to the photoreceptor by the pre-exposure means 11 before primary charging, and the residual charges are removed. It is better to remove electricity.

When the charging member of the present invention is used for transfer charging, it can be applied to, for example, an electrophotographic apparatus as shown in FIG. This apparatus includes a primary charging corona charger 14, an image exposure means 7, a developing means 8, a transfer charging member 15, a cleaning means 10, a pre-exposure means
11 are located.

A voltage (for example, a DC voltage of 400 to 1000 V) is applied to the transfer charging member 15 which is arranged in contact with the electrophotographic photosensitive member 12 to transfer the developer on the electrophotographic photosensitive member to a transfer member such as paper. Can be.

When the charging member of the present invention is used for static elimination charging, it can be applied to, for example, an electrophotographic apparatus as shown in FIG. 6. This apparatus has a primary charging corona on the peripheral surface of the electrophotographic photosensitive member 12. A charger 14, an image exposure unit 7, a developing unit 8, a transfer charging corona charger 9, and a cleaning unit 10 are arranged.

A voltage (for example, an AC peak-to-peak voltage of 500 to 2000) is applied to the charging member 16 for discharging and charging, which is disposed in contact with the electrophotographic photosensitive member 12.
V) can be applied to eliminate charges on the electrophotographic photosensitive member.

The charging member of the present invention exerts its characteristics remarkably by being applied to an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductor, which is susceptible to deterioration in mechanical strength and chemical stability. can do.

The charging member to be brought into contact with the photoreceptor in the present invention is not limited to a specific method, and the charging member may be fixed, or may be moved in the same direction as the photoreceptor or rotated in the opposite direction. it can. Further, it is also possible for the charging member to function as a developer cleaning device on the photosensitive member.

Applied voltage to the charging member in the direct charging of the present invention,
Regarding the application method, it depends on the specifications of each electrophotographic apparatus, but in addition to the method of applying the desired voltage instantaneously, the method of gradually increasing the applied voltage for the purpose of protecting the photoreceptor, the method of applying DC to AC Can be applied in the order of DC AC or AC DC in the case of superimposing.

When the charging member of the present invention is used for primary charging of an electrophotographic apparatus, it is necessary to superimpose a DC voltage and an AC voltage on an electrophotographic photosensitive member in an image output area.

When primary charging is applied only with a DC voltage, uniform charging cannot be performed.

When used for transfer charging, a DC voltage alone or a DC voltage and an AC voltage may be superimposed.

When used for static elimination charging, it is necessary to apply only an AC voltage.

In the present invention, the processes such as image exposure, development, and cleaning can employ any method known in the field of electrostatography, and are not limited to a specific type such as a type of developer. The charging member of the present invention is not limited to a copying machine, but may be a laser printer or a CRT printer,
It can also be used in electrophotographic application fields such as facsimile machines having an electrophotographic plate making system and a receiving means for receiving image information from a remote terminal.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1 An aluminum cylinder having a thickness of 0.5 mm and a diameter of 60 mm × 260 mm was prepared as a conductive support.

Copolymer nylon (trade name: CM8000, manufactured by Toray Industries, Inc.) 4
Part and type 8 nylon (trade name: Lacamide 500
3, Dainippon Ink Co., Ltd.) 4 parts methanol 50 parts, n
-Dissolved in 50 parts of butanol and dip-coated on the support to form a 0.6 μm thick undercoat layer.

10 parts of disazo pigment of the following structural formula, And polyvinyl butyral resin (trade name: Estelec)
BM2, Sekisui Chemical Co., Ltd.) 10 parts, cyclohexanone 120
The mixture was dispersed with a sand mill for 10 hours. 30 parts of methyl ethyl ketone was added to the dispersion, and the dispersion was coated on the undercoat layer to form a 0.15 μm thick charge generation layer.

Prepare 10 parts of polycarbonate Z resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a weight average molecular weight of 120,000, and prepare a hydrazone compound having the following structural formula. It was dissolved in 80 parts of monochlorobenzene together with 10 parts. This was applied on the charge generation layer to form a charge transport layer having a thickness of 16 μm, thereby producing an electrophotographic photosensitive member No. 1.

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
Melt and knead parts by weight, φ8 ×
It was formed into a diameter of 20 × 240 mm through a stainless steel shaft of 260 mm, and a conductive elastic layer of a roller-shaped charging member was provided.

The volume resistance of the conductive elastic layer of the charging member is set to 22
It is 3 × 10 ⁴ Ωcm when measured in an environment of 60 ° C. and 60% humidity.

Next, 20 parts by weight of polybutadiene (98% of 1,2 adduct, number average molecular weight of 20,000) was dissolved in 30 parts by weight of monochlorobenzene, and dip coating was performed on the conductive elastic layer of the charging member.
After drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member.

As shown in FIG. 3, this charging member is connected to a regular image copying machine PC.
-20 (manufactured by Canon) Attached in place of the primary corona charger, and driven to rotate with the electrophotographic photoreceptor, the primary charging voltage is a superposition of DC voltage -750V and AC peak-to-peak voltage 1500V, and the dark potential of the electrophotographic photoreceptor The potential measurement of bright potential and the image were examined.

 The results are shown in Table 1.

Further, the potential characteristics and images when the charging member was mounted on the positive development type copying machine at a temperature of 15 ° C. and a humidity of 10% in a low temperature and low humidity state were similarly examined, and the results are shown in Table 1.

Example 2 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared.

Next, a butadiene-styrene copolymer (styrene content
20% by weight of 25%, number average molecular weight of 20,000) is dissolved in 30 parts by weight of monochlorobenzene, dip coating is performed on the conductive elastic layer of the charging member, and after drying, a resin layer having a thickness of 200 μm is provided.
A roller-shaped charging member was manufactured.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

Example 3 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared.

Next, 20 parts by weight of a butadiene-acrylonitrile copolymer (acrylonitrile content: 25%, number average molecular weight: 20,000) was dissolved in 30 parts by weight of monochlorobenzene, and dip-coated on the conductive elastic layer of the charging member. 200μm after drying
And a roller-shaped charging member was manufactured.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

Comparative Example 1 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared.

Next, 5 parts by weight of 6-66-10-12 nylon was mixed with 90 parts of methanol.
It was dissolved in parts by weight, and was applied by dip coating on the conductive elastic layer of the charging member. After drying, a resin layer having a film thickness of 200 μm was provided to produce a roller-shaped charging member.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

Comparative Example 2 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

Next, 5 parts by weight of methoxymethylated nylon 6 (methoxymethylation rate: 25%) was dissolved in 90 parts by weight of methanol, dip-coated on the conductive elastic layer of the charging member, and dried to a thickness of 200 μm. A resin layer was provided, and a roller-shaped charging member was manufactured.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

Comparative Example 3 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared.

Next, 4 parts by weight of a polyester polyol (Nipporan 121, manufactured by Nippon Polyurethane Co., Ltd.) and 1 part by weight of tolylene diisocyanate were dissolved in 90 parts by weight of n-butanol.
Dip coating was performed on the conductive elastic layer of the charging member, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

Comparative Example 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

Next, 5 parts by weight of silicon RTV rubber was dissolved in 90 parts by weight of toluene, and the resultant was applied by dip coating on the conductive elastic layer of the charging member. After drying, a resin layer having a thickness of 200 μm was provided. Was manufactured.

 This was evaluated in the same manner as in Example 1 and shown in Table 1.

As can be seen by comparing Examples 1, 2, and 3 with Comparative Examples 1 and 2, the present invention can prevent generation of image defects of wavy fog caused by hardening of the resin layer at low temperature and low humidity.

Further, as can be seen by comparing Examples 1, 2, and 3 with Comparative Examples 3 and 4, it is possible to prevent fusion between the charging member and the photosensitive member and suppress the occurrence of a horizontal streak image.

Example 4 Hereinafter, characteristics as a transfer charger were examined.

 A photoconductor was produced in the same manner as in Example 1.

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
A part by weight was melted and kneaded, and formed into a φ30 × 240 mm through a stainless shaft of φ8 × 260 mm at the center to provide a conductive elastic layer of a roller-shaped transfer charging member.

This transfer charging volume resistance is 4 × 10 ⁴ Ωcm when measured in an environment at a temperature of 22 ° C. and a humidity of 60%.

Next, 10 parts by weight of polybutadiene (98% of 1,2 adduct, number average molecular weight of 20,000) is dissolved in 30 parts by weight of monochlorobenzene, dip-coated on the conductive elastic layer of the transfer charging member, and dried. A resin layer having a post-film thickness of 100 μm was provided to manufacture a roller-shaped transfer charging member.

This transfer charging member was attached in place of the transfer corona charger of the positive development type copying machine PC-20 (manufactured by Canon), and DC-500 V was applied for transfer charging, and the state of the image and the transfer charging member was examined.

 The results are shown in Table 2.

Further, the image and the state of the transfer charging member when the transfer charging member was mounted on a regular image copying machine in a low temperature and low humidity state of a temperature of 15 ° C. and a humidity of 10% were examined.

Example 5 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, a butadiene-styrene copolymer (styrene-containing layer
10% by weight of 25%, number average molecular weight of 20,000) is dissolved in 30 parts by weight of monochlorobenzene, dip-coated on the conductive elastic layer of the transfer charging member, and dried to form a 100 μm-thick resin layer. A roller-shaped transfer charging member was manufactured.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

Example 6 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, 10 parts by weight of a butadiene-acrylonitrile copolymer (acrylonitrile content: 25%, number average molecular weight: 20,000) is dissolved in 30 parts by weight of monochlorobenzene, and is dip-coated on the conductive elastic layer of the transfer charging member. And after drying 100
A roller-shaped transfer charging member was manufactured by providing a μm resin layer.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

Comparative Example 5 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, 5 parts by weight of 6-66-10-12 nylon was mixed with 90 parts of methanol.
Dissolved in parts by weight, dip coating on the conductive elastic layer of the transfer charging member, providing a resin layer having a thickness of 100 μm after drying,
A roller-shaped transfer charging member was manufactured.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

Comparative Example 6 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, 5 parts by weight of methoxymethylated nylon 6 (25% methoxymethylation rate) was dissolved in 90 parts by weight of methanol, dip-coated on the conductive elastic layer of the transfer charging member, and dried to a film thickness of 100 μm. To form a roller-shaped transfer charging member.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

Comparative Example 7 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, 4 parts by weight of a polyester polyol (Nipporan 121, manufactured by Nippon Polyurethane) and 1 part by weight of tolylene diisocyanate are dissolved in 90 parts by weight of n-butanol and dip coated on the conductive elastic layer of the transfer charging member. A resin layer having a dry film thickness of 100 μm was provided to manufacture a roller-shaped transfer charging member.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

Comparative Example 8 In the same manner as in Example 4, a conductive elastic layer of a transfer charging member was prepared.

Next, 5 parts by weight of silicon RTV rubber was dissolved in 90 parts by weight of toluene, and the resultant was applied by dip coating on the conductive elastic layer of the transfer charging member. After drying, a resin layer having a thickness of 100 μm was provided. The members for manufacture were manufactured.

 This was evaluated in the same manner as in Example 4, and is shown in Table 2.

As can be seen from Examples 4, 5, and 6 and Comparative Examples 5 and 6, according to the present invention, high image quality can be maintained without lowering of density or wavy fog even under low temperature and low humidity.

Further, as can be seen from Examples 4, 5, and 6 and Comparative Examples 7 and 8, in the present invention, since the transfer charging member does not fuse with the photoconductor and does not fuse with the toner, defects occur in the photoconductor and the charging member. It can be used without.

Example 7 Hereinafter, characteristics as a static eliminator were examined.

 A photoconductor was produced in the same manner as in Example 1.

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
A part by weight was melt-kneaded and molded on a 2 mm × 260 mm stainless plate at the center so as to have a free length of 10 mm × 240 mm as shown in FIG. 3 to provide a conductive elastic layer of a blade-shaped charging member. The volume resistance of the charge removing member is set to a temperature of 22 ° C and a humidity of 60.
It is 4 × 10 ⁴ Ωcm when measured in a% environment.

Next, 10 parts by weight of polybutadiene (98% of 1,2 adduct, number average molecular weight of 20,000) is dissolved in 30 parts by weight of monochlorobenzene, dip-coated on the conductive elastic layer of the charge removing member, and dried. A resin layer having a post-film thickness of 100 μm was provided, and a blade-shaped member for static elimination and charging was manufactured.

This static elimination charging member is installed in place of the pre-exposure static eliminator of the positive development type copier PC-20 (manufactured by Canon). For static elimination, an AC peak-to-peak voltage of 1000 V is applied. The state of the members for use was examined.

 The results are shown in Table 3.

Further, the image and the state of the charge-eliminating member when the charge-eliminating member was attached to the positive development copying machine at a low temperature and a low humidity of 15 ° C. and a humidity of 10% were examined.

Example 8 In the same manner as in Example 7, a conductive elastic layer of a member for discharging and charging was prepared.

Next, a butadiene-styrene copolymer (styrene ratio 25
%, Number average molecular weight 20,000) 10 parts by weight of monochlorobenzene
After dissolving in 30 parts by weight, dip coating was performed on the conductive elastic layer of the charge eliminating charge member, and after drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped charge eliminating charge member.

 This was evaluated in the same manner as in Example 7 and shown in Table 3.

Example 9 In the same manner as in Example 7, a conductive elastic layer of a charge removing member was prepared.

Next, 10 parts by weight of a butadiene-acrylonitrile copolymer (acrylonitrile content: 25%, number average molecular weight: 20,000) is dissolved in 30 parts by weight of monochlorobenzene, and then dip-coated on the conductive elastic layer of the charge removing member. And after drying 100
A μm resin layer was provided, and a blade-shaped member for static elimination charging was manufactured.

 This was evaluated in the same manner as in Example 7 and shown in Table 3.

Comparative Example 9 In the same manner as in Example 7, a conductive elastic layer of a member for discharging and charging was prepared.

The charge removing member was used without providing a resin layer.

 This was evaluated in the same manner as in Example 7 and shown in Table 3.

Comparative Example 10 In the same manner as in Example 7, a conductive elastic layer of a member for discharging and charging was prepared.

Next, 10 parts by weight of methoxymethylated nylon-6 was dissolved in 90 parts by weight of methanol, dip-coated on the conductive elastic layer of the member for static elimination and charging, and after drying, a resin layer having a thickness of 100 μm was provided. A member for shape neutralization and charging was manufactured.

 This was evaluated in the same manner as in Example 7 and shown in Table 3.

Comparative Example 11 In the same manner as in Example 7, a conductive elastic layer of a member for discharging and charging was prepared.

Next, 8 parts by weight of a polyester polyol (Nipporan 121, manufactured by Nippon Polyurethane) and 2 parts by weight of toluylene diisocyanate are dissolved in 90 parts by weight of n-butanol, and dip-coated on the conductive elastic layer of the member for static elimination and charging. After drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped member for static elimination and charging.

 This was evaluated in the same manner as in Example 7 and shown in Table 3.

Comparative Example 12 The static elimination was carried out by pre-exposure without using the static elimination charging member of the present invention, and this was evaluated in the same manner as in Example 7. Table 3 shows the results.

As can be seen by comparing Examples 7, 8, and 9 with Comparative Rows 9 and 11, in the present invention, the fusion between the charging member and the photoconductor is prevented, and the occurrence of horizontal stripe-shaped image defects is prevented.

Further, as can be seen by comparing Examples 7, 8, and 9 with Comparative Example 10, stable static electricity elimination performance was exhibited even at low temperature and low humidity, and the material of the present invention can suppress image defects.

In Comparative Example 12, the static elimination performance was low in the conventional pre-exposure type static elimination, and the residual potential was likely to remain at low temperature and low humidity, causing a background fog defect.

〔The invention's effect〕

As is clear from the above results, by using the charging member of the present invention, the adhesion to the electrophotographic photoreceptor is low and the flexibility is high, so that a high-quality image is provided and the toner smear is small. Especially stable potential characteristics even under low temperature and low humidity,
Image characteristics are obtained.

[Brief description of the drawings]

1 and 2 are cross-sectional views in the direction of the central axis of a roller-shaped charging member, FIG. 3 is a cross-sectional view of a blade-shaped charging member, and FIGS. 4, 5, and 6 are cross sections of an electrophotographic apparatus. FIG. 1a conductive support, 1b conductive sheet metal, 2 conductive elastic layer, 3 resin layer, 4 protective layer, 5 resin powder, 6 charging member, 7 ... Image exposure means, 8 development means, 9 corona charger for transfer charging, 10 cleaning means, 11 pre-exposure means, 12 electrophotographic photosensitive member,
14 Corona charger for primary charging, 15 Charging member for transfer charging, 16 Charging member for static elimination charging.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-50172 (JP, A) JP-A-1-267667 (JP, A) JP-A-64-7086 (JP, A) JP-A-60-1985 216361 (JP, A) JP-A-61-151570 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/02 G03G 15/16 G03G 21/06

Claims (5)

(57) [Claims] 1. A charging member having a conductive elastic layer on a conductive support, wherein polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer or butadiene-butene copolymer is formed on the conductive elastic layer. A charging member comprising a resin layer containing a coalescence. 2. The charging member according to claim 1, wherein said photosensitive member is charged by contact with said electrophotographic photosensitive member. 3. The charging member according to claim 1, wherein the electrophotographic photosensitive member is primarily charged by applying a voltage obtained by superimposing a DC voltage and an AC voltage. 4. The charging member according to claim 1, wherein the developer is transferred from the electrophotographic photosensitive member to the member to be transferred by applying a DC voltage or a voltage obtained by superimposing a DC voltage and an AC voltage. 5. The charging member according to claim 1, wherein said electrophotographic photosensitive member is neutralized by applying an AC voltage.