JPH0457073A - Member for electrification - Google Patents

Abstract

PURPOSE:To obtain the member which has the lower adhesiveness to an electrophotographic sensitive body and good pliability and forms high-quality images by providing a resin layer contg. graphite fine particle on a conductive elastic layer. CONSTITUTION:The conductive elastic layer 2 is provided on a conductive base 1 and the resin layer 3 is provided on the elastic layer 2. This resin layer 3 is constituted of a material contg. graphite fine particle in a binder resin. While the thickness of the resin layer 3 varies with conditions, such as the amt. of the graphite fine particle to be incorporated, the thickness is preferably 5 to 500mum. The volume resistivity of the resin layer is preferably larger than that of the elastic layer 2 and is specified to a 10<6> to 10<12>OMEGAcm range. A liquid prepd. by dissolving a resin, such as polyvinyl butyral, by an org. solvent is used for a protective layer. The adhesiveness to the electrophotographic sensitive body is lessened by incorporating the graphite fine particle into the resin layer in such a manner. Since the resin layer has the pliability as well, the high- quality images are obtd. and the staining with toners is lessened.

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.
Charging is performed by corona generated by applying a voltage of 5 to 8 KV. However, with this method, when corona occurs, the surface of the photoreceptor is altered by corona products such as ozone and NO, causing image blurring and deterioration, and wire dirt affects image quality, resulting in white spots and black spots in the image. There were problems such as streaks. On the other hand, in terms of electric power, the current flowing to the photoreceptor is only 5 to 30% of the total current, and most of it flows to the shield plate, making it ineffective as a charging means.

In order to compensate for these drawbacks, direct charging methods have been researched and many proposals have been made (for example, JP-A No. 57-17
8267, JP 56104351, JP 58-40566, JP 511139156
(Japanese Patent Application Laid-Open No. 150975/1984, etc.).

[Problem to be solved by the invention]

However, even if the photoreceptor is charged by the above-described direct charging method, uniform charging is not achieved over the entire surface of the photoreceptor, and the occurrence of spot-like charging unevenness is unavoidable. When photoimage exposure and subsequent processes are applied to a photoreceptor with such spotty uneven charging,
The resulting output image is a speckled black dot image corresponding to speckled charging unevenness in the reversal development method, and a speckled white dot image in the regular image method, making it impossible to obtain a high-quality image.

Furthermore, although there are many proposals for the direct charging method,
There is no market track record. Reasons for this include non-uniform charging and occurrence of dielectric breakdown due to discharge of the photoreceptor due to direct application of voltage. For example, in the case of a cylindrical photoreceptor, a breakdown point caused by dielectric breakdown due to discharge causes the charged charge to flow in the axial direction toward the breakdown point, resulting in a disadvantage that the photoconductor is no longer charged.

In order to prevent this dielectric breakdown, charging members with a resin layer provided on the surface have also been reported (for example, JP-A-1-2003)
5180 and Japanese Unexamined Patent Publication No. 1211779). However, these materials also have large fluctuations in resistance at low temperatures and low humidity, and are unstable in their charging properties.Also, when used in contact with an organic photoreceptor, the resins may bond with each other on the surface of the organic photoreceptor and the charging member. They had defects such as becoming compatibilized and sticking to each other. Further, there is a lot of dirt and dust adhering to the surface of the charging member, which is the reason why durability is not improved. Toner that has been poorly cleaned adheres to the charging member and accumulates, causing filming and deteriorating charging performance. The use of resin powder is also being considered as a way to make it easier for toner to slide on the surface of the charging member (
However, due to the insulating properties of the resin, the resin powder itself deteriorates the charging performance.

The present invention has been made in order to solve the above-mentioned problems with conventional charging members, and can stably supply high-quality images without spotty fog caused by uneven charging. An object of the present invention is to provide a charging member with excellent durability.

[Means and effects for solving the problems] The present invention provides a charging member comprising a conductive support and a conductive elastic body provided thereon, in which fine graphite powder is contained on the conductive elastic body. It is characterized by being provided with a resin layer.

The present invention will be explained in more detail below with reference to the drawings.

The charging member of the present invention is, for example, a roller-shaped member as shown in FIG. A resin layer 3 is provided on the elastic layer 2. The resin layer 3 is made of a binder resin mixed with fine graphite powder.

That is, since the charging member of the present invention has the resin layer 3 mixed with fine graphite powder on the conductive elastic layer 2, it has less adhesion to the electrophotographic photoreceptor and is flexible, so it can achieve high image quality. It can be advantageously used as a charging member that provides an image, has little toner stain, has little variation in the volume resistivity of the resin layer even under low temperature and low humidity conditions, and is durable.

On the other hand, conventional charging members have surfaces made of rubber or polyurethane, so if they are left in contact with the electrophotographic photoreceptor, they may stick to the photoreceptor, or if the surface is hard, they may not adhere to the photoreceptor. This caused image defects due to the occurrence of wrinkles. According to the invention, all such drawbacks are eliminated.

In the charging member of the present invention, the thickness of the resin layer 3 is preferably in the range of 5 to 500 μm, particularly 20 to 200 μm, although it varies depending on conditions such as the amount of graphite fine powder mixed.

Binder resins include polyamide, polyurethane,
Acrylic resins such as polymethyl methacrylate or polybutyl methacrylate, polyvinyl butyral, polyvinyl acecool, polyarylate, polycarbonate, phenoxy resin, polyvinyl acetate, polyvinylpyridine, and the like can be mentioned.

The fine graphite powder mixed into the binder resin is generally a gray to black, glossy, highly slippery crystalline mineral, and is known as a raw material for pencil leads. There are natural and synthetic types, both of which can be used in the present invention. The average particle size of the fine graphite powder is preferably 10μ or less, preferably in the range of 0.1μ to 5μ.

It is preferable that the resin layer 3 has a volume resistivity in the range of 10 6 to 10 12 Ω·Cl11. Also, the 6th special request
As described in No. 2-230334, the resin layer 3
It is preferable that the volume resistivity of the elastic layer 2 is larger than that of the elastic layer 2 in contact with the elastic layer 2. The volume resistivity of the elastic layer 2 is to'~10 1Ω・CIl+, especially 102~1
A range of 0I0Ω·cm is preferable. As the elastic layer 2,
Metals such as aluminum, iron, copper, conductive polymers such as polyacetylene, polypyrrole, polythiophene, rubber or insulating resins treated with conductivity with carbon or metals, or insulating resins such as polycarbonate, polyester, or rubber surfaces made of metal. It is possible to use a material coated with a laminate with a conductive material such as .

Further, the elastic layer 2 may have a multilayer structure in which each layer has a separate function.

As the material of the conductive substrate 1, iron, copper, stainless steel, etc. can be used.

Furthermore, as shown in FIG. 2, the charging member may have a protective layer 4 for protecting the resin layer 3 as the outermost layer.

This protective layer 4 may have particles 5 mixed therein, such as conductive particles for controlling conductivity or insoluble resin particles for controlling surface roughness.

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 above-mentioned 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 blank, tin oxide particles, etc.) together with a suitable binder, or a conductive binder. It is possible to use plastics that have

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

The subbing layer is casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer polyamide,
It can be formed from polyurethane, gelatin, aluminum oxide, etc. The thickness of the subbing layer is 5 μm or less, preferably 0.
．． A suitable thickness is 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 7 Ω·cm 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 quinacridine 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 fats 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. In addition, examples of organic photoconductive polymers include carbazole, polyvinylanthracene,
Examples include polyvinylpyrene.

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. Organic solvents include alcohols, sulfoxides, ethers, esters, and aliphatic solvents. Rogenated 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 hydrazone 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,
Mention may be made of polyester, alkyd resin, polycarbonate, polyurethane, or copolymers containing two or more repeating units of these resins, such as styrene-butadiene copolymer, styrene-acrylonite copolymer, styrene-maleic acid copolymer, etc. can. 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 5:1
~1:5, preferably 3:l ~ 1:3 degree. 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 must be 101+.
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 an appropriate organic solvent and coating it 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. This device includes a primary charging member 6 on the circumferential surface of a drum-shaped electrophotographic photoreceptor 12;
Image exposing means 7, developing means 8, transfer charging means 9, cleaning means 10, and pre-exposure means 11 are arranged.

The primary charging member 6 placed in contact with the electrophotographic photoreceptor 12 is applied with an external voltage (for example, 200V 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 4000 V or less between peaks, and the image on the document is imaged onto the photoreceptor by the image exposure means 7. Exposure to light to form an electrostatic latent image. Next, the electrostatic latent image on the photoreceptor is developed (visualized) by adhering the developer in the developing means 8 to the photoreceptor, and then the developer on the photoreceptor is transferred to the paper by the charging means 9. The developer is transferred to a transfer member 13 such as a photoreceptor, and the 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 eliminate 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, and a developing means 8 are provided on the circumferential surface of an electrophotographic photoreceptor 12.
, a charging member 15 for transfer charging, and a cleaning means IO1 pre-exposure means 11 are arranged.

A voltage (for example, a DC voltage of 400 to 1000
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 14 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.

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 applied voltage and applied force method to the charging member in the direct charging of the present invention, it depends on the specifications of each electrophotographic device, but in addition to the method of instantaneously applying a desired voltage, it is also possible to protect the photoreceptor. A method can be adopted in which the applied voltage is increased step by step, or in the case of applying a superimposed alternating current on direct current, the voltage is applied in the order of alternating current (direct current) or alternating current and then 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.

Furthermore, 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 copiers but also in electrophotographic applications such as laser printers, CRT printers, and electrophotographic plate making systems.

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. During the rotation process, the photoreceptor 101 is uniformly charged to a predetermined positive or negative potential on its circumferential surface by the charging means 102 of the present invention, and then exposed to a light image by an image exposure means (not shown) in the exposure section 103 using a slit. light exposure, laser beam scanning exposure, etc.). 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 a developing means 104, and the toner image is transferred from a paper feeding section (not shown) by a transfer means 105 to a photoreceptor 101 between the photoreceptor 101 and 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 No. 1.

The transfer material P that has undergone the image transfer is separated from the photoreceptor surface and introduced into the image fixing means 8, where the image is fixed and a copy is produced.
will be printed out on the outside of the aircraft.

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. Further, for the transfer device 105, corona transfer means is generally widely used. 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-mentioned device unit may include a charging means and/or a developing means.

In addition, when using an electrophotographic device as a copying machine or printer, optical image exposure involves scanning the reflected light or transmitted light from the document, or by reading the document and converting it into a signal. 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 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. Predetermined image data is stored in the image memory. A printer controller 118 controls a printer 119. 114 is a telephone.

Images received from the line 115 (image information from a remote terminal connected via the line) are demodulated by the receiving circuit 112, and then the CPU 117 decodes the image information and sequentially stores it in the image memory 116. . Then, once at least one page of images is stored in the memory 116,
Record an image of that page. CP[1117 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 CPt1
When it receives one page of image information from l17, it controls the printer 119 to record the image information of that page.

Note that during recording by the printer 119, the CPU 117
The next page is being received.

As described above, images are received and recorded.

Examples of the present invention are shown below.

Example 1 As a conductive support, 60φ×26 with a wall thickness of 0.5 mm
An aluminum cylinder with zero opening was prepared.

4 parts of copolymerized nylon (trade name: CM8000, manufactured by Toshiku Co., Ltd.) and 4 parts of type 8 nylon (trade name: Lasocamide 5003, manufactured by Dainippon Ink Co., Ltd.) were mixed with 5 parts of methanol.
0 parts and n-butanol were dissolved in 50 parts of n-butanol and dip coated onto the above support to form a 0.6 μm thick undercoat layer.

10 parts of a disazo pigment with the following structural formula, and polyvinyl butyral resin (trade name: Esresoku B)
10 parts of M2 (manufactured by Sekisui Chemical Co., Ltd.), 1 part of cyclohexanone
Dispersion was carried out with 20 parts in a sand mill apparatus for 10 hours. 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 together 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 with a thickness of 16 μm, thereby producing an electrophotographic photoreceptor M1.

Next, conductive carbon 5 was added to 100 parts by weight of chloroprene rubber.
The weight part was melt-kneaded and molded into a diameter of 20 x 240 mm through a stainless steel shaft of 8 x 260 mm in the center, and 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 x 106 Ωcm.

Next, 3 parts by weight of natural graphite fine powder (C3P manufactured by Nippon Graphite Co., Ltd.) and 7 parts by weight of nylon copolymer (0M8000 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. 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. 4.
-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.

The results are shown in Table 1.

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

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

Next, natural graphite fine powder (C3PE made by Nippon Graphite) 4
Parts by weight and 6 parts by weight of -methoxymethylated nylon-6 (methoxymethylation rate 28%) 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 3 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

Next, artificial graphite fine powder (UPG-2 manufactured by Showa Denko)
2 parts by weight and 8 parts by weight of polyvinyl butyral (BX-II! Water Chemical) were 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 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

Next, artificial graphite fine powder (UFG-2 manufactured by Showa Denko)
4 parts by weight and 6 parts by weight of vinyl chloride and vinyl acetate copolymer (manufactured by VMCH1UCC) 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 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+, 9o).

3 parts by weight of Columbia Carbon Co., Ltd.) and 7 parts by weight of a nylon copolymer (CM8000) 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 2 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

Next, polytetrafluoroethylene fine powder (Luburon L-
2 (manufactured by Daikin) and 2 parts by weight of nylon copolymer (CM8)
000 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.

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 (Kyner Tomoe Industries) 2
Parts by weight and polyvinyl butyral (Suresoku BX-1
8 parts by weight (manufactured by Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

A roller-shaped charging member was manufactured by dip coating on the electrosensitive 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.

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 BX1 Sekisui Chemical) was dissolved in 90 parts by weight of methyl ethyl ketone, and the solution was dip-coated on the conductive elastic layer of the charging member to form a resin layer with a thickness of 200 μm after drying. A roller-shaped charging member was manufactured.

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 1-ner 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.

Next, we investigated its characteristics as a transfer charger.

Example 5 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 parts were melt-kneaded, passed through a stainless steel shaft of 8 mm x 260 mm in the center, and molded to a size of 30 mm x 240 mm, and a conductive elastic layer of a roller-shaped 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 4×106 Ωcm.

Next, 4 parts by weight of natural graphite fine powder (Japanese graphite C3P) and 6 parts by weight of nylon copolymer (0M8000 East) were dissolved in 90 parts by weight of ethanol, and the solution was dipped onto the conductive elastic layer of the transfer charging member. After coating and drying, the film thickness is 100μ
A resin layer of m 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, and the state of the image and the transfer charging member was It was investigated.

The results are shown in Table 2.

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

Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5.

Next, 5 parts by weight of natural graphite fine powder (Japanese graphite C3PE) and 5 parts by weight of methoxymethylated nylon-6 (methoxymethylation rate 28%) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

A roller-shaped transfer charging member was manufactured by dip coating the conductive elastic layer of the transfer charging member and providing a resin layer with a thickness of 100 μm after drying.

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, artificial graphite fine powder (Showa Denko UFG-2) 3
Part by weight and polyvinyl butyral (BX-1 Sekisui Chemical)
7 parts by weight 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 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, artificial graphite fine powder (Showa Denko tlFG-2)
5 parts by weight and vinyl chloride, vinyl acetate copolymer (VMCHlUCC)
5 parts by weight 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 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.

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

Next, 3 parts by weight of conductive carbon (Conductesox 0900 manufactured by Columbia Carbon) and nylon copolymer (0
7 parts by weight of M8000 East) 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 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 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5.

Next, polytetrafluoroethylene fine powder (Luburon L-
2 (manufactured by Daikin) and 2 parts by weight of nylon copolymer (0M8
000 manufactured by Toshi) 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 200 μm was provided to produce a roller shape transfer charging member.

This was evaluated in the same manner as in Example 5 and 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, polyvinylidene fluoride fine powder (Kyner Tomoe Industries) 2
Parts by weight and polyvinyl butyral (Suresoku BX-1
8 parts by weight (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, 10 parts by weight of polyvinyl butyral (Suresoku BX1 Sekisui Chemical) 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 transfer charging member, and after drying, a resin layer with a film thickness of 200 μm was formed. 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 transfer performance deteriorated during durability, resulting in a decrease in concentration.

Next, we investigated its characteristics as a static eliminator.

Example 9 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 parts to form a 2 mm x 260 mm piece at the center.
on a stainless steel plate with a free length of 10 mm as shown in Figure 3.
It was molded to have a length of 240 mm, and a conductive elastic layer of a blade-shaped charging member was provided. When the volume resistivity of this static electricity removal charging member is measured in an environment of temperature 22℃ and humidity 60%, it is 4XIO.
' Ωcm.

Next, 3 parts by weight of natural graphite fine powder (C3P manufactured by Nippon Graphite Co., Ltd.) and 7 parts by weight of nylon copolymer (0M8000 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, and a blade-shaped static elimination/charging member as shown in FIG. 3 was manufactured. 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 parts was examined.

The results are shown in Table 3.

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

Example 10 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared.

Next, natural graphite fine powder (C3PE made by Nippon Graphite) 4
Parts by weight and 6 parts by weight of methoxymethylated nylon-6 (methoxymethylation rate 28%) 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 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, artificial graphite fine powder (Showa Denko UFG-2) 2
Part by weight and polyvinyl butyral (BX-1 Sekisui Chemical)
8 parts by weight 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 thickness of 100 μm was provided to produce a blade shape transfer charging member.

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

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

Next, carpenter graphite fine powder (UFG2 manufactured by Showa Denko) 4
Parts by weight and vinyl chloride, vinyl acetate copolymer (VMCH).

(manufactured by UCC) was 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 9 In the same manner as in Example 9, a conductive elastic layer of a static elimination/charging member was prepared.

Next, 3 parts by weight of conductive carbon (Conductesox 0900 manufactured by Columbian Carbon) and nylon copolymer (C
7 parts by weight of M8000 East) 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, polytetrafluoroethylene fine powder (Luburon L-
2 (manufactured by Daikin) and 2 parts by weight of nylon copolymer (CM8)
000 manufactured by Toshi) was 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 film thickness of 100 mm and 1711 mm was provided to produce a blade-shaped static eliminating and 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, polyvinylidene fluoride fine powder (manufactured by Kyner Tomoe Industries)
2 parts by weight and polyvinyl butyral (Suresoku BX-
1 (manufactured by Sekisui Chemical) was 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 (Suresoku 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, a resin layer with a film thickness of 100 μM was formed. 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 Examples 9.10.11.12 and Comparative Example 9.12, the present invention prevents filming due to toner stains on the charging member during durability, suppresses residual potential, and prevents the occurrence of soil burr. It can be prevented.

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 static elimination performance deteriorated during durability, resulting in vertical streak defect images.

〔Effect of the invention〕

As explained above, the charging part of the present invention has a resin layer mixed with fine graphite powder on the conductive elastic layer, so that it has less adhesion to the electrophotographic photoreceptor.
It also has good flexibility, and therefore, when applied to an electrophotographic device or a copying machine, 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, so it provides high quality images. It also has excellent durability and can maintain the above effects for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a roller-shaped charging member according to the present invention, FIG. 2 is a longitudinal sectional view showing another roller-shaped charging member according to the invention, and FIG. 3 is a longitudinal sectional view showing a blade-shaped charging member according to the present invention. FIG. 4 is a longitudinal cross-sectional view showing a charging member, FIG. 4 is a schematic vertical cross-sectional view of an electrophotographic apparatus equipped with the charging member of the present invention shown in FIG. 1 or FIG. 2, and FIG. FIG. 2 is a schematic vertical cross-sectional view of an electrophotographic apparatus equipped with the charging member of the present invention for transfer charging, and FIG. 6 is a schematic longitudinal sectional view of a normal development type copying machine equipped with the charging member of FIG. 3. 7 is a schematic vertical sectional view of a general transfer type electrophotographic apparatus using a drum type photoreceptor, and FIG. 8 is a block diagram showing the configuration of the apparatus shown in FIG. 7. (2) is a conductive support, 2 is a conductive elastic layer, 3 is a resin layer, and 4 is a conductive support.
1 is a protective layer, 5 is a particle, 6 is a primary charging member, 7 is an image exposure means, 8 is a developing means, 9 is a transfer charging means, 10 is a cleaning means, 11 is a pre-exposure means, 12 is a photoreceptor, 13 14 is a corona charger for primary charging; L5. ．．
16 is a charging member. Diagram

Claims (4)

[Claims] (1) A charging member comprising a conductive support and a conductive elastic body provided thereon, characterized in that a resin layer containing fine graphite powder is provided on the conductive elastic body. Parts for use. (2) The charging member according to claim 1, further comprising a protective layer as an outermost layer for protecting the resin layer. (3) The charging member according to claim 1 or 2, wherein the resin layer has a volume resistivity in the range of 10^6 to 10^1^2 Ω·cm. (4) The charging member according to any one of claims 1 to 3, wherein the resin layer has a thickness within a range of 5 to 500 μm.