JPH04106565A - Part for electrification - Google Patents

Abstract

PURPOSE:To obtain a durable member part which can stably give high-quality picture images without speckle-type fogging by providing a resin layer containing conductive carbon and graphite fine powder on a conductive elastic layer. CONSTITUTION:A conductive elastic layer 2 is provided on a conductive supporting body 1a and further a resin layer 3 containing conductive carbon and graphite fine powder is formed thereon. The particle sizes of the graphite fine powder and conductive carbon are average <=10mum and <=100mum, respectively. The resin layer consists of a binder resin. When this electrifying part is used for primary electrification, DC voltage and AC voltage are superimposed thereon. For the use of transfer electrification, only DC voltage or both of DC and AC voltage may be applied. For use in destatization/electrification, only AC voltage is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a charging member, and more particularly to a charging member used for primary charging, transfer charging, and static elimination charging in electrophotography.

[Conventional technology]

The charging process in the electrophotographic process using an electrophotographic photoreceptor has conventionally applied a high voltage (DC) to a metal wire.
5 to 8 kV) is applied, and charging is performed by the generated corona. However, with this method, when corona occurs, corona products such as ozone and NOx alter the surface of the photoreceptor, causing image blurring and deterioration, and dirt on the wire affects the quality of the image, resulting in white spots and black lines in the image. There were some problems such as: On the other hand, in terms of electric power, the current flowing toward the photoreceptor is
The amount was only ~30%, and most of it flowed to the shield plate, making it ineffective as a charging means.

In order to compensate for these drawbacks, many methods of direct charging have been researched and proposed (Japanese Unexamined Patent Publications No. 178-267-1982, No. 104-351-1983, No. 4-4 of 1983)
0566, JP-A-58-139156, JP-A-58150975, etc.). However, in reality, even if the photoreceptor is charged by the contact charging method as described above, the surface of the photoreceptor is not uniformly charged at each part, and uneven charging occurs. For example, in the reversal development method, even if a process below photoimage exposure is applied to a photoconductor with spotty charging unevenness, the output image will be a spotty black dot image corresponding to the spotty charging unevenness, whereas in the regular development method, the output image will be a spotty black dot image corresponding to the spotty charging unevenness. In contrast to the unevenness, the image becomes a speckled white dot image, making it impossible to obtain a high-quality image.

Further, although there are many proposals for the direct charging method, there is no market experience at all. The reason for this is the uniformity of charging,
Examples include orders for discharge dielectric breakdown of photoreceptors by directly applying voltage. For example, in the case of a cylindrical photoreceptor, one breakdown point due to discharge dielectric breakdown has the disadvantage that the entire charge in the axial direction flows to the breakdown point and is no longer charged.

[Problem to be solved by the invention]

In order to prevent this dielectric breakdown, a method of forming a resin layer on the surface has also been reported. (Unexamined Japanese Patent Publication No. 1-205180,
(Japanese Patent Application Laid-Open No. 1-211779) However, these materials also have large fluctuations in resistance under low temperature and low humidity conditions, have unstable charging properties, and when used in contact with an organic photoreceptor, the contact between the organic photoreceptor and the charging member may deteriorate. It had defects such as the resins on the surfaces becoming compatibilized and sticking together.

Further, the charging member lacks durability because dirt, dust, etc. tend to adhere to its surface. In particular, residual toner due to poor cleaning of the photoreceptor adheres to the surface of the charging member and gradually accumulates, causing a filming phenomenon, resulting in deterioration of charging performance.

In addition, a method of attaching resin powder to the surface of the charging member to improve the lubricity of the surface in order to prevent filming phenomena has been considered (Japanese Patent Application Laid-Open No. 1-66673), but the resin itself is insulating. Therefore, charging performance was degraded.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a durable charging member that can solve the above-mentioned drawbacks, stably supply high-quality images without spot-like fog due to uneven charging.

[Means to solve the problem]

That is, the present invention provides a charging member having a conductive elastic layer on a conductive support, characterized in that a resin layer containing conductive carbon and graphite fine powder is provided on the conductive elastic layer. It is a member for use.

The present invention will be explained in more detail below.

As shown in FIG. 1, the charging member of the present invention includes a conductive elastic layer 2 provided on a conductive support la, and a resin layer containing conductive carbon and graphite fine powder on the elastic layer 2. The basic form is a three-layer structure in which 3 are provided.

In the present invention, graphite fine powder is a gray to black, shiny, slippery crystalline mineral that is used in pencils and the like. It also has good conductivity. There are two types of graphite: natural and artificial, and both can be used.

In the present invention, the average particle size of the fine graphite powder is 10 μm or less. Preferably 0.1 μm or more and 5 μm
It is as follows.

Further, in the present invention, the conductive carbon is a polymer of a substance containing carbon as a main component and having a fine particle size. In addition to being a black pigment, this conductive carbon has functions such as reinforcing various substances and improving electrical properties.

Further, the particle size of the conductive carbon used in the present invention is preferably 100 m or less in average particle size, more preferably 10 m or less.
It is not less than mμ and not more than 50 mμ.

Further, as a specific example of the conductive carbon used in the present invention, Columbian Carbon rRAVEN125 manufactured by Nippon
5 J rcONDUcTEX 975 BEADS
J,rcONDIJcTEX 900 BEADS
J, rcONDtlcTHX SCJ, "Easy Dispersibility Denka Black" manufactured by Denki Kagaku Kogyo ■, and "Ketchen Black ECJ" manufactured by Lion ■.

Further, a binder resin is used in the resin layer.

As the binder resin in the resin layer, polyamide,
Examples include acrylic resins such as polyurethane, polymethyl methacrylate, and polybutyl methacrylate, polyvinyl butyral, polyvinyl acetal, polyarylate, polycarbonate, phenoxy resin, polyvinyl acetate, and polyvinylpyridine.

The above-mentioned graphite fine powder is preferably added to the binder resin in an amount of 1 to 30% by weight.

Further, the conductive carbon is preferably added in an amount of 1 to 30% by weight in the binder resin.

The ratio of the amount added (fine graphite powder/conductive carbon) is preferably 9/1 to 1/2.

Conventional charging members have surfaces made of rubber or polyurethane, so if they come into contact with an electrophotographic photoreceptor, the photoreceptor and charging member may stick together, or if the surface is hard, wrinkles may occur. This caused image defects.

Furthermore, toner that has been poorly cleaned tends to adhere, forming a toner filming layer on the surface of the charging member, resulting in charging failure, and a durable charging member cannot be obtained.

On the other hand, the charging member having a resin layer containing conductive carbon and graphite fine powder of the present invention has low adhesion to the electrophotographic photoreceptor and is flexible, so it provides high-quality images. There is little toner staining, and there is little variation in the volume resistivity of the resin layer even under low temperature and low humidity conditions, so it can be used as a durable charging member. Also, the addition amount ratio is 9/1
By reducing the thickness to 1/2, durability can be significantly improved.

The thickness of the resin layer is 5 to 500 μm, particularly 20 to 200 μm.
A range of m is preferred.

The volume resistivity of the resin layer is preferably in the range of 106 to 1012 Ω·1, and as shown in Japanese Patent Application No. 62-230334, the volume resistivity of the resin layer is determined by the volume of the lower conductive elastic layer in contact with the resin layer. It is preferable that it is larger than the resistivity.

The volume resistivity of the elastic layer is preferably in the range of 1O9 to 10I'Ω·1, particularly 102 to 10I0Ω·1. Elastic layer 2
Examples include metals such as aluminum, iron, and copper, conductive polymers such as polyacetylene, polypyrrole, and polythiophene,
Rubber or plastic elastomer that has been treated to be conductive by dispersing carbon, metal, etc., or a rubber or plastic elastomer whose surface is laminated and coated with metal or other conductive substance can be used. Also,
This elastic layer 2 may have a multilayer structure with separate functions as required. As the conductive support 1a, iron, copper, stainless steel, etc. can be used.

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 insoluble resin powder 5 may be mixed therein to control the conductivity and the surface roughness of the charging member.

In the case of a plate-shaped charging member as shown in FIG. 3, a conductive elastic layer 2 is provided on the conductive sheet metal ibO, and a resin layer 3
will be established.

Further, a protective layer may be provided.

The charging member may have any shape such as a roller shape or a blade shape, but a roller shape is preferable in terms of uniform charging.

Electrophotographic photoreceptors basically have a structure in which a photosensitive layer is provided on a conductive support. As the conductive support, materials that are conductive themselves such as aluminum, aluminum alloy, stainless steel, chromium, titanium, etc. can be used. In addition, aluminum, aluminum alloy, indium oxide-tin oxide alloy, etc. can be used. The conductive support or plastic has a layer formed by vacuum deposition, a support in which plastic or paper is impregnated with conductive particles (e.g. carbon black, tin oxide particles, etc.) together with a suitable binder, or a conductive binder. Plastic or the like can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The subbing layer can be formed from casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid coholic acid polyamide, polyurethane, gelatin, aluminum oxide, or the like. The thickness of the undercoat layer is suitably 5 μm or less, preferably 0.5 to 3 μm. In order for the undercoat layer to perform its function, it is desirable that the undercoat layer has a resistance of 10'Ω·1 or more.

The photosensitive layer is formed, for example, by coating a photoconductor such as an organic photoconductor, amorphous silicon, selenium, etc. together with a binder if necessary, or by vacuum deposition. Furthermore, when using an organic photoconductor, a photosensitive layer consisting of a combination of a charge generation layer that generates charge carriers upon exposure to light and a charge transport layer that has the ability to transport the generated charge carriers can also be effectively used.

The charge-generating layer may be formed by depositing one or more charge-generating materials such as azo pigments, quinone pigments, quinone-anine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, and quinacridone pigments, or by depositing a suitable material. It can be dispersed with a binder (or without a binder) and formed by coating.

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

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

The solvent used in the paint for the charge generation layer is selected based on the solubility and dispersion stability of the resin and charge transport material used, and examples of organic solvents include alcohols, sulfoxides, ethers, esters, and aliphatic halogenated solvents. Hydrocarbons or aromatic compounds can be used.

Coating can be carried out using a coating method such as a dip coating method, a spray coating method, a Meyer bar coating method, or a blade coating method.

The charge transport layer is formed by dissolving a charge transport material in a film-forming resin. Examples of organic charge transport materials used in the present invention include vidrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds,
Examples include thiazole compounds and triarylmethane compounds.

These charge transport materials can be used alone or in combination of two or more.

Examples of binders used in 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, and epoxy. resin, polyester, alkyd resin, polycarbonate, polyurethane, or two of the repeating units of these resins
copolymers containing one or more, such as styrene-butadiene copolymers, styrene-acrylonitrile copolymers,
Examples include styrene-maleic acid copolymer. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

The thickness of the charge transport layer is 5 to 50 μm, preferably 8 to 20 μm.
μm, and the weight ratio of charge transport material and binder is 5:
The degree is 1 to 1:5, preferably 3:1 to 1:3. The coating method described above can be used for coating.

Furthermore, dyes, pigments, organic charge transport substances, and the like are generally susceptible to ultraviolet rays, ozone, stains caused by oil, and metals, so a protective layer may be provided as necessary. In order to form an electrostatic latent image on this protective layer, the surface resistivity is 1011.
It is desirable that it is Ω or more.

The protective layer of the photoreceptor is made of polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin,
It can be formed by dissolving a resin such as nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer, etc. in a suitable organic solvent on the photosensitive layer and drying it. . At this time, the thickness of the protective layer is generally in the range of 0.05 to 20 μm.

This 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 means 7, a developing means 8, a corona charger 9 for transfer charging, a cleaning means 10, and a pre-exposure means 11 are arranged on the circumferential surface of an electrophotographic photoreceptor 12. .

The primary charging member 6 placed in contact with the electrophotographic photoreceptor 12 is applied with an external voltage (for example, 200 μm or more
The surface of the electrophotographic photoreceptor 12 is charged by applying a pulsating voltage that is a superimposition of a DC voltage of V or less and an AC voltage of 4000V or less between peaks, and the image on the document is transferred to the photoreceptor by the image exposure means 7. Expose to light to form an electrostatic latent image. Next, by attaching the developer in the developing means to the photoreceptor, the electrostatic latent image on the photoreceptor is developed (visualized), and then the developer on the photoreceptor is transferred to a corona charger for transfer charging. 9 transfers the developer onto a transfer member 13 such as paper, and a cleaning means 10 collects the developer remaining on the photoreceptor without being transferred to the paper during transfer.

Images can be formed by such an electrophotographic process, but if residual charges remain on the photoreceptor, the photoreceptor is exposed to light by the pre-exposure means 11 to remove the residual charges before primary charging. It is better to remove the static electricity.

When using the charging member of the present invention for transfer charging, for example,
It can be applied to an electrophotographic apparatus as shown in FIG. In this apparatus, a corona charger 14 for primary charging, an image exposure means 7, a developing means 8, a charging member 15 for transfer charging, a cleaning means 10, and a pre-exposure means 11 are arranged on the circumferential surface of an electrophotographic photoreceptor 12. There is.

A voltage (for example, a DC voltage of 400 to 100 O
V) can be applied to transfer the developer on the electrophotographic photoreceptor to a transfer member such as paper.

When the charging member of the present invention is used for static electricity removal charging, for example,
It can be applied to an electrophotographic apparatus as shown in FIG. In this apparatus, a corona charger 4 for primary charging, an image exposure means 7, a developing means 8, a corona charger 9 for transfer charging, and a cleaning means 10 are arranged on the circumferential surface of an electrophotographic photoreceptor 12.

A voltage (for example, an AC peak-to-peak voltage of 500 to 500
2000V) can be applied to remove the electric charge on the electrophotographic photoreceptor.

By applying the charging member of the present invention to an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductor, which easily deteriorates in terms of mechanical strength and chemical stability, its characteristics can be clearly exhibited. can do.

In the present invention, the method for installing the charging member in contact with the photoreceptor is not limited to a specific method.
Any method of movement such as rotation in the same direction as the photoreceptor or in the opposite direction can be used. Furthermore, it is also possible to cause the charging member to function as a developer cleaning device on the photoreceptor.

Regarding the voltage applied to the charging member and the application method in the direct charging of the present invention, it depends on the specifications of each electrophotographic device, but in addition to the method of instantly applying the desired voltage, there are also methods for protecting the photoreceptor. A method can be adopted in which the applied voltage is increased stepwise, or in the case of applying a superimposed alternating current on direct current, a method can be adopted in which the voltage is applied in the order of direct current and alternating current or alternating current and direct current.

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

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

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 alternating current voltage.

FIG. 7 shows a schematic configuration of a general transfer type electrophotographic apparatus using a drum-type photoreceptor.

In the figure, reference numeral 101 denotes a drum-type photoreceptor as an image carrier, which is rotated at a predetermined circumferential speed in the direction of the arrow around a shaft 101a. The photoreceptor 101 is uniformly charged at a predetermined positive or negative potential on its circumferential surface by the charging means (charging member) 102 of the present invention during its rotation process, and then the photoreceptor 101 is charged uniformly at a predetermined positive or negative potential by the charging means (charging member) 102 of the present invention.
At step 3, the photoreceptor is subjected to optical image exposure (slit exposure, laser beam scanning exposure, etc.) by an image exposure means (not shown). As a result, electrostatic latent images corresponding to the exposed images are sequentially formed on the circumferential surface of the photoreceptor.

The electrostatic latent image is then developed with toner by the developing means 104, and the toner developed image is transferred from a paper feed section (not shown) to the photoreceptor 101 and the transfer means 105 by the transfer means 105.
The images are sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the rotation of 01.

The transfer material P that has undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 108, where the image is fixed and printed out outside the machine as a copy.

The surface of the photoreceptor 101 after image transfer is cleaned by cleaning means 10.
At step 6, the remaining toner is removed and the surface is made clean, which is repeatedly used for image formation.

As the uniform charging means 102 for the photoreceptor 101, the charging member of the present invention is used. Furthermore, corona transfer means is used as the transfer means 105.

An electrophotographic apparatus is constructed by combining a plurality of components such as the above-mentioned photoreceptor, developing means, and cleaning means into an apparatus unit, and this unit is configured to be detachable from the apparatus main body. It's okay. For example, the photoreceptor 101 and the cleaning means 106 may be integrated into one apparatus unit, and may be configured to be detachable using a guide means such as a rail of the apparatus main body. At this time,
The above device unit may be configured with a charging means and/or a developing means.

Furthermore, when using an electrophotographic device as a copying machine or printer, light image exposure uses the reflected light or transmitted light from the original, or the original is read and converted into a signal, and this signal is used to scan the laser beam and light emitting diode. This is performed by driving an array or driving a liquid crystal shutter array.

Furthermore, when used as a facsimile printer, the optical image exposure is exposure for printing received data. FIG. 8 is a block diagram showing an example of this case.

The controller 111 controls the image reading unit 110 and the printer 1.
Controls 19. The entire controller 111 is CPU1
17. The read data from the image reading section 110 is transmitted to the partner station through the transmitting circuit 113. Data received from the partner station is sent to the printer 119 through the receiving circuit 112. Image memory 116 stores predetermined image data. Printer controller 1
18 controls a printer 119. 114 is a telephone.

Image information received from the line 115 (image information from a remote terminal connected via the line) is sent to the receiving circuit 11
After being demodulated in step 2, the CPU 117 performs decoding processing, and the images are sequentially stored in the image memory 116. Then, when at least one page of image information is stored in the memory 116, the image of that page is recorded. The CPU 117 reads one page of image information from the memory 116 and sends the decoded one page of image information to the printer controller 118. The printer controller 118 is a CPU
When the image information of one page is received from the printer 117, the printer 119 is controlled to record the image of that page.

Note that the CPU 117 is receiving the next page while the printer 119 is recording.

Images are received and recorded in the manner described above.

Further, in the present invention, processes such as image exposure, development, and cleaning can be performed using any method known in the field of electrostatic photography, and are not limited to a specific type of developer.

The charging member of the present invention can be used not only in copying machines but also in electrophotographic applications such as laser printers, CRT printers, and electrophotographic plate making systems.

〔Example〕

The present invention will be explained below using examples.

Example 1 As a conductive support, 60φ×2 with a wall thickness of 0.5 tan
A 60 mm aluminum cylinder was prepared.

Copolymerized nylon (product name: CM8000, manufactured by Toshi ■)
Part 4 and Type 8 nylon (trade name Niratsukamite 5)
003, manufactured by Dainippon Ink), 50 parts of methanol,
It was dissolved in 50 parts of n-butanol and applied on the above support by dip coating to form a 0.6 μm thick undercoat layer.

10 parts of a disazo pigment with the following structural formula, and polyvinyl butyral resin (product name: S-LEC B)
10 parts of M2 (manufactured by Sekisui Chemical Co., Ltd.), 12 parts of cyclohexanone
It was dispersed for 10 hours in a sand mill with 0 parts. 30 parts of methyl ethyl ketone was added to the dispersion and coated on the undercoat layer to form a charge generation layer with a thickness of 0.15 μm.

10 parts of polycarbonate Z resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a weight average molecular weight of 120,000 was prepared and dissolved in 80 parts of monochlorobenzene along with 10 parts of a hydrazone compound having the following structural formula. This was coated on the charge generation layer to form a charge transport layer having a thickness of 16 μm, thereby producing an electrophotographic photoreceptor N01.

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
Melt and knead the weight part and form φ8X in the center as a conductive support.
φ20X240am+ through 260- stainless steel shaft
A conductive elastic layer of a roller-shaped charging member was provided.

The volume resistance of the conductive elastic layer of this charging member is determined at a temperature of 22
When measured in an environment of ℃ and 60% humidity, it is 3×10'Ω1.

Next, 0.6 parts by weight of conductive carbon (Conductex C900, manufactured by Columbia Carbon), 3 parts by weight of natural graphite fine powder (CSP, manufactured by Nippon Graphite), and 7 parts by weight of nylon copolymer (CM8000, manufactured by Toshi). was added to 90 parts by weight of ethanol and dispersed in a ball mill.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member. A resin layer was similarly provided on an aluminum sheet, and the volume resistance was measured.

This charging member is connected to a normal development type copying machine PC as shown in Fig. 3.
-20 (manufactured by Canon) - Installed in place of the next corona charger and rotated in accordance with the electrophotographic photoreceptor. Potential measurements and images of dark potential and bright potential were examined.

Furthermore, 5,000 images were repeatedly taken, and the potential measurements and images after durability were examined.

The results are shown in Table 1.

Example 2 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, conductive carbon (Conductesox C-900,
0.7 parts by weight (manufactured by Columbia Carbon), 4 parts by weight of natural graphite fine powder (C3PE, manufactured by Nippon Graphite), and methoxymethylated nylon-6 (methoxymethylation rate 2
8%) was added to 90 parts by weight of ethanol and dispersed in a ball mill.

A roller-shaped charging member was manufactured by dip coating on the conductive elastic layer of the charging member and providing a resin layer with a thickness of 200 μm after drying.

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

Example 3 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1 using zero-order conductive carbon (Conductex C-900,
0.51 parts (manufactured by Columbia Carbon), 2 parts by weight of artificial graphite fine powder (manufactured by Showa Denko), and 8 parts by weight of polyvinyl butyral (BX-1゜Building Chemical) were added to 90 parts by weight of ethanol, and dispersed in a ball mill. .

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member.

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

Example 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, conductive carbon (Conductex C-900,
0.9 parts by weight (manufactured by Columbia Carbon), 4 parts by weight of artificial graphite fine powder (manufactured by Showa Denko), and 6 parts by weight of vinyl chloride-vinyl acetate copolymer (VMCf (manufactured by UCC) were added to 90 parts by weight of methyl ethyl ketone, and the mixture was placed in a ball mill. and dispersed.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member.

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

Comparative Example 1 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, conductive carbon (Conductesox C-900,
(manufactured by Columbia Carbon) and 7 parts by weight of nylon copolymer (CM8000, manufactured by Toshi) in 90 parts of ethanol.
In addition to parts by weight, they were dispersed in a ball mill.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member.

This was evaluated in the same manner as in Example 1 and is 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, polytetrafluoroethylene fine powder (Luburon)
2, 2 parts by weight (manufactured by Daikin) and nylon copolymer (CM
8000. 8 parts by weight (manufactured by Toshi) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member.

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

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

Next, polyvinylidene fluoride fine powder (manufactured by Kyner Tomoe Industries)
2 parts by weight and polyvinyl butyral (S-LEC BX-
1. Sekisui Chemical Co., Ltd.) 8 parts by weight were added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member.

This was evaluated in the same manner as in Example 1 and is 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, 10 parts by weight of polyvinyl butyral (S-LEC BX-1, manufactured by Miki Kagaku) was dissolved in 90 parts by weight of methyl ethyl ketone, and the solution was dip-coated onto the conductive elastic layer of the charging member to form a resin film with a thickness of 200 μm after drying. A layer was provided to produce a roller-shaped charging member.

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

As can be seen by comparing Examples 1.2.3.4 and Comparative Example 1.4, the present invention can prevent filming due to toner stains on the charging member during durability and can prevent image defects from occurring.

Further, as can be seen by comparing Examples 1.2.3.4 and Comparative Example 4, it is possible to prevent fusion between the charging member and the photoreceptor, and to suppress the occurrence of horizontal stripe defect images.

In Comparative Examples 2.3, a resin lubricating additive was used, and the charging performance deteriorated during durability, resulting in a decrease in concentration.

Example 5 Below, the characteristics as a transfer charger were investigated.

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

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
Melt and knead the weight part and pass it through the center with a stainless steel shaft of φ8 x 260 mm. Molded to OX240m,
A conductive elastic layer of a roller shape transfer charging member was provided.

The volume resistance of this transfer charging member was determined at a temperature of 22°C and a humidity of 60°C.
% environment, it is 4X10'Ωcm.

Next, 0.9 parts by weight of conductive carbon (Condex C-900, manufactured by Columbian Carbon), 4 parts by weight of natural graphite fine powder (C3P, manufactured by Nippon Graphite), and 6 parts by weight of nylon copolymer (CM8000, manufactured by Toshi). Parts by weight were added to 90 parts by weight of ethanol and dispersed in a ball mill.

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 to produce a roller shape transfer charging member. A resin layer was similarly provided on the aluminum sheet, and the volume resistance was measured.

This transfer charging member was installed in place of the transfer corona charger of the normal development type copying machine PC-20 (manufactured by Canon) as shown in Fig. 5, and a direct current of -500 V was applied for transfer charging. We examined the state of

Furthermore, 5,000 images were repeatedly taken, and the potential measurements and images after durability were examined.

The results are shown in Table 2.

Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, conductive carbon (Condextex C-90
0.0, manufactured by Columbia Carbon), 5 parts by weight of natural graphite fine powder (Japanese graphite, C3PE), and methoxymethylated nylon 6 (methoxymethylation rate 28
%) was added to 90 parts by weight of ethanol and dispersed in a ball mill.

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 to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Example 7 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, conductive carbon (Condextex C-90
0.0, manufactured by Columbia Carbon), 3 parts by weight of Carpenter graphite fine powder (Showa Denko type), and 7 parts by weight of polyvinyl butyral (BX-1゜ manufactured by Block Chemical) were added to 9 parts by weight of methyl ethyl ketone, and then milled in a ball mill. It was dispersed.

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 to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Example 8 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, conductive carbon (Condextex C-90
0.8 parts by weight of (manufactured by Columbian Carbon), 5 parts by weight of artificial graphite fine powder (Showa Denko type), and 5 parts by weight of vinyl chloride-acetate copolymer (VMCH, manufactured by UCC90) were added to 90 parts by weight of methyl ethyl ketone, and the mixture was placed in a ball mill. and dispersed.

dip coating on the conductive elastic layer of the transfer charging member;
A resin layer having a thickness of 1100 a after drying was provided to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Comparative Example 5 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, conductive carbon (Conductenx C-90
0, produced by Columbia Carbon] and 7 parts by weight of a nylon copolymer (CM8000, produced by Toshi) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

A resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Comparative Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, 2 parts by weight of polytetrafluoroethylene fine powder (Luburon L-2, manufactured by Daikin) and nylon copolymer CM8000. 8 parts by weight (manufactured by Toshi) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

A resin layer having a thickness of 200 pm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Comparative Example 7 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, 2 parts by weight of polyvinylidene fluoride fine powder (Kynar, manufactured by Tomoe Kogyo) and 8 parts by weight of polyvinyl butyral (S-LEC BX-1, manufactured by Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

dip coating on the conductive elastic layer of the transfer charging member;
After drying, a resin layer having a thickness of 200 μm was provided to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Comparative Example 8 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, polyvinyl butyral (S-LEC BX-1
．． Sekisui Chemical Co., Ltd.) is dissolved in 90 parts by weight of methyl ethyl ketone and applied by dip coating on the conductive elastic layer of the transfer charging member to form a resin layer with a thickness of 200 μm after drying.
A roller shape transfer charging member was manufactured.

This was evaluated in the same manner as in Example 5 and is shown in Table 2.

As can be seen by comparing Example 5.6.7.8 and Comparative Example 5.8, the present invention prevents filming due to toner stains on the charging member during durability, and reduces image defects such as low density and white spots. Occurrence can be prevented.

Further, as can be seen by comparing Examples 5, 6, 7, and 8 with Comparative Example 8, it is possible to prevent the charging member from fusing with the photoreceptor and to suppress the occurrence of horizontal stripe defect images.

In Comparative Examples 6 and 7, a resin lubricating additive was used, and the charging performance deteriorated during durability, resulting in a decrease in concentration.

Example 9 Below, we investigated its characteristics as a static eliminator.

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

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
The weight part was melted and kneaded and molded onto a stainless steel plate of 2 x 260 pieces in the center to have a free length of 10 x 240 pieces as shown in Figure 3, and a conductive elastic layer of the blade-shaped charging member was formed. Established. The volume resistance of this static eliminating charging member is determined at a temperature of 22°
When measured in an environment with C1 humidity of 60%, it is 4 x 104 Ωcm. Next, conductive carbon (Conductex C-900,
0.8 parts by weight of Columbian Carbon), 3 parts by weight of natural graphite fine powder (C3P, manufactured by Nippon Graphite), and 7 parts by weight of nylon copolymer (CM8000, Toshi 90) were added to 90 parts by weight of ethanol, and the mixture was milled in a ball mill. It was dispersed.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer with a film thickness of 100 μm was provided to produce a blade-shaped static elimination/charging member. A resin layer was similarly provided on the aluminum sheet, and the volume resistance was measured.

As shown in Fig. 6, this charge-eliminating member is installed in place of the pre-exposure charge eliminator of the normal development type copying machine PC-20 (manufactured by Canon), and an AC peak-to-peak voltage of 1000 V is applied to remove the charge from the image. The condition of the charging member was examined.

Furthermore, 5,000 images were repeatedly taken, and the potential measurement and images after durability were examined.

The results are shown in Table 3.

Example 10 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, conductive carbon (Conductesox C-90
0. 4 parts by weight of natural graphite fine powder (C3PE, manufactured by Nippon Graphite) and 6 parts by weight of methoxymethylated nylon-6 (methoxymethylation rate 28%) were added to 90 parts by weight of ethanol, and the mixture was placed in a ball mill. and dispersed.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer with a film thickness of 100 μm was provided to produce a blade-shaped static elimination/charging member.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Example 11 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, conductive carbon (Condextex C-90
0.0, manufactured by Columbia Carbon), 3 parts by weight of Carpenter graphite fine powder (Showa Denko type), and 8 parts by weight of polyvinyl butyral (BX-1, manufactured by Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone, and the mixture was placed in a ball mill. and dispersed.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer with a film thickness of 100 μm was provided to produce a blade-shaped static elimination/charging member.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Example 12 Similarly to Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, conductive carbon (Condextex C-900
, manufactured by Columbia Carbon), 4 parts by weight of artificial graphite fine powder (Showa Denko type), and 6 parts by weight of vinyl chloride-vinyl acetate copolymer (VMCH, manufactured by UCC) were added to 90 parts by weight of methyl ethyl ketone, and dispersed in a ball mill. did.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer with a film thickness of 1100 IJ was provided to produce a blade-shaped static elimination/charging member.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Comparative Example 9 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, conductive carbon (Conductenx C-90
3 parts by weight of Colombian carbon fiber and 7 parts by weight of a nylon copolymer (CM8000 manufactured by Toshi) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Comparative Example 10 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, 2 parts by weight of polytetrafluoroethylene fine powder (Luburon L-2, manufactured by Daikin) and nylon copolymer CM8000. 8 parts by weight (manufactured by Toshi) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer having a thickness of 100 μm was provided to produce a roller-shaped static elimination/charging member.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Comparative Example 11 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared. Next, 2 parts by weight of polyvinylidene fluoride fine powder Kynar (manufactured by Tomoe Kogyo) and 8 parts by weight of polyvinyl butyral (S-LEC BX-1, manufactured by Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

Dip coating on the conductive elastic layer of the static elimination charging member,
After drying, a resin layer with a film thickness of 100 μm was provided to produce a blade-shaped static elimination/charging member.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

Comparative Example 12 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared.

Next, 10 parts by weight of polyvinyl butyral (S-LEC BX1, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 90 parts by weight of methyl ethyl ketone, and the solution was applied by dip coating onto the conductive elastic layer of the static eliminating charge member, and after drying, the resin layer had a film thickness of 100 μm. A blade-shaped static elimination/charging member was manufactured.

This was evaluated in the same manner as in Example 9 and is shown in Table 3.

As can be seen by comparing Example 9.10.1112 and Comparative Example 9.12, the present invention can prevent filming due to toner stains on the charging member during durability, suppress the residual potential, and prevent the occurrence of soil blurring. .

In addition, as can be seen by comparing Examples 9, 10, 11, 12 and Comparative Example 12, fusion between the charging member and the photoreceptor was prevented,
It is possible to suppress the occurrence of horizontal stripe defect images.

In Comparative Examples 10 and 11, a resin lubricating additive was used, and the charging performance deteriorated during durability, resulting in vertical streak defect images.

〔Effect of the invention〕

As is clear from the above results, by using the charging member of the present invention, the adhesion to the electrophotographic photoreceptor is low;
It is also flexible and provides high quality images. In particular, there is no toner filming phenomenon even during durability.
Good potential characteristics and image characteristics are maintained.

[Brief explanation of drawings]

Figures 1 and 2 are sectional views in the central axis direction of a roller-shaped charging member, Figure 3 is a sectional view of a blade-shaped charging member, and Figures 4, 5, and 6 are cross-sectional views of an electrophotographic device. It is a diagram. FIG. 7 is a schematic diagram of a general transfer type electrophotographic apparatus. FIG. 8 is a block diagram of a facsimile machine using an electrophotographic device as a printer. 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: developing means,
9: Corona charger for transfer charging, 10 Cleaning means, 11: Pre-exposure means, 12: Electrophotographic photoreceptor, 14 Corona charger for primary charging, 15: Charging member for transfer charging, 16: Charger for neutralizing charge Members, 101: Photoreceptor, 102: Charging means, 103: Exposure section, 104: Developing means, 105: Transfer means, 106
:Cleaning means, :Pre-exposure means, :Image fixing means.

Claims (5)

[Claims] (1) A charging member having a conductive elastic layer on a conductive support, the charging member comprising a resin layer containing conductive carbon and fine graphite powder on the conductive elastic layer. (2) The charging member according to claim 1, wherein the charging member contacts an electrophotographic photoreceptor to charge the photoreceptor. (3) The charging member according to claim 1, wherein the electrophotographic photoreceptor is primarily charged by superimposing a DC voltage and an AC voltage as applied voltages. (4) The charging member according to claim 1, wherein the developer is transferred from the electrophotographic photoreceptor to the transfer member by using a DC voltage as the applied voltage or by superimposing a DC voltage and an AC voltage. (5) The charging member according to claim 1, wherein the electrophotographic photoreceptor is neutralized using an alternating current voltage as the applied voltage.