JP2929558B2 - Charging member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging member, and more particularly to a charging member used for primary charging, transfer charging, and charge removal in electrophotography.

[0002]

2. Description of the Related Art Conventionally, in a charging process in an electrophotographic process using an electrophotographic photosensitive member, charging is performed by a corona generated by applying a high voltage (5 to 8 kV DC) to a metal wire. However, if at the time of corona generating in this way, by corona products such as ozone and NO _x denature the surface of the photosensitive member, allowed to proceed for image blurring or deterioration,
There is a problem in that the stain on the wire affects the image quality, causing white spots and black stripes on the image. 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 the current flows to the shield plate.

In order to compensate for such a drawback, methods of direct charging have been studied, and many methods have been proposed (for example, Japanese Patent Application Laid-Open Nos. 57-178267 and 56-10435).
No. 1, JP-A-58-40566, JP-A-58-40566
-139156, JP-A-58-150975, etc.).

[0004]

However, even if the photoreceptor is charged by the above-described direct charging method, in practice, uniform charging over the entire surface of the photoreceptor is not achieved.
It is inevitable that spot-like uneven charging occurs. When a photoreceptor having such spot-like charging unevenness is subjected to light image exposure and the subsequent process, the resulting output image is
In the reversal development method, a spot-like black spot image corresponding to spot-like charging unevenness is obtained, and in the normal development method, a spot-like white spot image is obtained, and a high-quality image cannot be obtained.

[0005] The direct charging method has no market record at all, despite many proposals. The reasons for this include non-uniform charging and the occurrence of dielectric breakdown due to discharge of the photoconductor due to direct application of a voltage. In the case of a cylindrical photoreceptor, for example, in the case of a cylindrical photoreceptor, a charged point flows in an axial direction toward the broken point, and a breakdown point caused by dielectric breakdown due to discharge causes a defect that charging is stopped.

In order to prevent this dielectric breakdown, charging members provided with a resin layer on the surface have also been reported (for example, JP-A-1-205180 and JP-A1-211779).
No.). However, these materials also have large fluctuations in resistance under low temperature and low humidity, and their charging properties are unstable. Also, when they are used in contact with an organic photoreceptor, when the resin is used in contact with the organic photoreceptor and the charging member, the resin forms Had a defect that they were compatible with each other and stuck to each other. Also, dust on the surface of the charging member,
A large amount of dust adheres, which causes the durability to not be improved. In addition, poor cleaning toner adheres to and accumulates on the charging member, causing a phenomenon of filming, thereby deteriorating charging performance. As a method of making the toner slip on the surface of the charging member, use of a resin powder has been studied (Japanese Patent Laid-Open No. 1-66673). However, the resin powder itself is charged due to the insulating property of the resin. Performance was to be degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional charging member, and stably supplies a high-quality image without spot-like fog due to uneven charging. It is an object of the present invention to provide a charging member which can be formed and has excellent durability.

[0008]

According to the present invention, there is provided a charging member comprising a conductive support and a conductive elastic body provided thereon, wherein a resin layer containing carbon fibers is provided on the conductive elastic body. Is provided.

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

The charging member of the present invention is, for example, a roller as shown in FIG. 1 and includes a conductive support 1 in the form of a shaft and a conductive elastic layer 2 provided therearound. The resin layer 3 is provided on the conductive elastic layer 2. The resin layer 3 is made of a material in which carbon fibers are mixed in a binder resin.

That is, since the charging member of the present invention has the resin layer 3 in which carbon fibers are mixed on the conductive elastic layer 2,
Low adhesion to electrophotographic photoreceptor and high flexibility, giving high quality image, less toner stain, less change in volume resistance of resin layer even under low temperature and low humidity, and durable It can be advantageously used as a charging member.

On the other hand, since the surface of the conventional charging member is made of rubber or polyurethane, if it is kept in contact with the electrophotographic photoreceptor, it will stick to the photoreceptor or if the surface is hard, Image defects were caused by wrinkling of the photoreceptor. According to the present invention, all such disadvantages are eliminated.

In the charging member of the present invention, the thickness of the resin layer 3 varies depending on conditions such as the amount of carbon fiber mixed therein, but is preferably in the range of 5 to 500 μm, particularly preferably 20 to 200 μm.

Examples of the binder resin include an acrylic resin such as polyamide, polyurethane, polymethyl methacrylate or polybutyl methacrylate, polyvinyl butyral, polyvinyl acetal, polyarylate, polycarbonate, phenoxy resin, polyvinyl acetate, polyvinyl pyridine and the like. it can.

The carbon fibers to be mixed into the binder resin are manufactured from three kinds of raw materials, such as polyacrylonitrile, rayon and pitch. From the point of strength, it is classified into a low modulus product (LM), a medium strength product (A), a high strength product (HS), a high modulus product (HM), and a super high modulus product (UHM).

The carbon fibers used in the present invention may have any strength. Particularly, an LM type graphite material is preferable.

The carbon fiber used in the present invention has a fiber diameter of 10 μm.
Hereinafter, those having a fiber length of 20 μ to 10,000 μ are used.

The resin layer 3 preferably has a volume resistivity in the range of 10 ⁶ to 10 ¹² Ω · cm. Further, as described in Japanese Patent Application No. 62-230334, the volume resistivity of the resin layer 3 is preferably larger than that of the elastic layer 2 in contact therewith. The volume resistivity of the elastic layer 2 is 10 ⁰ to 10 ¹¹ Ω · cm, especially 10 ² to 10
A range of ¹⁰ Ω · cm is preferred. Examples of the elastic layer 2 include metals such as aluminum, iron, and copper, conductive polymers such as polyacetylene, polypyrrole, and polythiophene; rubber and an insulating resin conductively treated with carbon or a metal; and insulating resins such as polycarbonate and polyester. Alternatively, a material obtained by laminating the surface of rubber with a conductive material such as metal or the like can be used. The elastic layer 2 may have a multilayer structure in which individual functions are assigned to each layer.

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

Further, as shown in FIG. 2, the charging member comprises:
A protective layer 4 for protecting the resin layer 3 may be provided on the outermost layer. The protective layer 4 may be formed by mixing particles 5 such as conductive particles for controlling conductivity or insoluble resin particles for controlling surface roughness. As shown in FIG. 3, a conductive elastic layer 2 attached to a flat conductive support 1 is provided.
It may have a structure in which the resin layer 3 is provided thereon. The resin layer 3 is made of a material in which carbon fibers are mixed in a binder resin.

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

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

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

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

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

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

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

The solvent used for the coating for the charge generating layer is selected from the solubility and dispersion stability of the resin and the charge transporting material used. Examples of the organic solvent include alcohols, sulfoxides, ethers, esters, and fatty acids. An aromatic halogenated hydrocarbon or an aromatic compound can be used.

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

The charge transport layer is formed by dissolving a charge transport material in a resin having a film forming property. Examples of the organic charge transporting material used in the present invention include a hydrazone compound,
Examples include stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials are 1
They can be used alone or in combination of two or more.

Examples of the binder used for the charge transport layer include:
Phenoxy resin, polyacrylamide, polyvinyl butyral, polyarylate, polysulfone, polyamide,
Acrylic resin, acrylonitrile resin, methacrylic resin,
Vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or a copolymer containing two or more of repeating units of these resins, for example, styrene-
Butadiene copolymers, styrene-acrylonitrile polymers, styrene-maleic acid copolymers and the like can be mentioned. Also, poly-N-vinyl carbazole,
It can also be selected from organic photoconductive polymers such as polyvinyl anthracene and polyvinyl pyrene.

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

Further, pigments, pigments, organic charge transporting substances, etc. are generally stained by ultraviolet rays, ozone, oil, etc.
A protective layer may be provided as necessary because it is weak against metals and the like. In order to form an electrostatic latent image on the protective layer, the surface resistivity is desirably 10 ¹¹ Ω or more.

The protective layer of the photoreceptor is polyvinyl butyral,
Polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate,
A station in which a resin such as polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer or the like is dissolved by a suitable organic solvent is applied on the photosensitive layer, and dried. At this time, the thickness of the protective layer is generally in the range of 0.05 to 20 μm. The protective layer may contain an ultraviolet absorber or the like.

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

An external voltage (for example, 200) is applied to the primary charging member 6 which is arranged in contact with the electrophotographic photosensitive member 12.
DC voltage between V and 2000V and peak-to-peak voltage 400
The surface of the electrophotographic photosensitive member 12 is charged, and an image on an original is image-exposed to the photosensitive member by the image exposure means 7 to form an electrostatic latent image. . Next, the electrostatic latent image on the photoconductor is developed (visualized) by attaching the developer in the developing unit 8 to the photoconductor,
Further, the developer on the photoreceptor is transferred to the transfer member 13 such as paper by the transfer charging means 9, and the developer remaining on the photoreceptor without being transferred to the paper at the time of transfer is collected by the cleaning means 10.

An image can be formed by such an electrophotographic process. However, if residual charge remains on the photosensitive member, the photosensitive member is exposed to light by the pre-exposure means 11 before primary charging. It is better to remove the charge.

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

A voltage (for example, a DC voltage of 4) is applied to the charging member 15 for transfer charging, which is disposed in contact with the electrophotographic photosensitive member 12.
00 to 1000 V) to transfer the developer on the electrophotographic photosensitive member to a member to be transferred such as paper.

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

A voltage (for example, an AC peak-to-peak voltage of 500 to 2,000 V) is applied to the charge member 16 for static elimination charging, which is disposed in contact with the electrophotographic photoreceptor 12, to eliminate the charge on the electrophotographic photoreceptor.

The charging member of the present invention is applied to an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductor, which is liable to deteriorate in mechanical strength and chemical stability.
The characteristics can be remarkably exhibited.

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

The voltage applied to the charging member and the method of application in the direct charging of the present invention depend on the specifications of each electrophotographic apparatus. For the purpose of (1), a method of increasing the applied voltage in a stepwise manner, or a method of applying a voltage in the form of DC → AC or AC → DC in the case of applying AC in a form of superimposing AC on DC can be adopted.

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

When the primary charging is applied only with a DC voltage,
It cannot be charged uniformly.

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

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

In the present invention, processes such as image exposure, development, and cleaning can employ any method known in the field of electrostatography, and are limited to specific ones such as the type of developer. Not something. The charging member of the present invention can be used not only for copying machines but also for laser printers and CRTs.
It can also be used in electrophotographic applications such as printers and electrophotographic prepress systems.

FIG. 7 shows a schematic configuration of a general transfer type electrophotographic apparatus using a drum type photosensitive member.

In FIG. 1, reference numeral 101 denotes a drum-type photosensitive member as an image bearing member, which is driven to rotate around an axis 101a in a direction indicated by an arrow at a predetermined peripheral speed. The photoreceptor 101 receives a uniform charge of a predetermined positive or negative potential on its peripheral surface by the charging means 102 of the present invention during the rotation process.
Receives light image exposure L (slit exposure, laser beam scanning exposure, etc.) by an image exposure means (not shown). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then developed with toner by the developing means 104. The toner development is performed by the transfer means 105 between the photosensitive body 101 and the transfer means 105 from a paper feeding unit (not shown) by the rotation of the photosensitive body 101. The transfer material P is sequentially transferred onto the surface of the transfer material P which has been synchronized and fed.

The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out of the machine as a copy.

The surface of the photoreceptor 101 after the image is transferred is cleaned by the cleaning unit 106 to remove the untransferred toner, and is repeatedly used for image formation.

As the uniform charging means 102 for the photosensitive member 101, the charging member of the present invention is used. Transfer device 1
05 also generally uses corona transfer means. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is configured to be detachable from the apparatus body. May be. 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 body. At this time,
The above-mentioned device unit may be provided with a charging unit and / or a developing unit.

In the case where the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is a light reflected from or transmitted from the original, or a read signal of the original, and is converted into a signal by this signal. The driving is performed by driving a light emitting diode array or a liquid crystal shutter array.

When used as a facsimile printer, the light image exposure L is an 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 119. The entire controller 111 is controlled by the CPU 117. The read data from the image reading unit is transmitted to the partner station through the transmission 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. Printer controller 1
Reference numeral 18 controls the printer 119. 114 is a telephone.

The image received from the line 115 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 112, and then the CPU 117 performs a decoding process of the image information and sequentially stores the image information in the image memory 116. Is stored.
When the image of at least one page is stored in the memory 116, the image of the page is recorded. CPU1
Reference numeral 17 reads out one page of image information from the memory 116 and sends the decoded one page of image information to the printer controller 118. Printer controller 118
The printer 1 receives the image information of one page from the CPU 117 and records the image information of the page.
19 is controlled.

The CPU 117 receives the next page during recording by the printer 119.

As described above, image reception and recording are performed.

Examples of the present invention will be described below.

[0063]

EXAMPLE 1 As a conductive support, a thickness of 0.5 mm and a size of 60φ × 260 were used.
mm aluminum cylinder was prepared.

Copolymer nylon (trade name: CM8000,
4 parts of Toray Industries, Inc. and Type 8 nylon (trade name:
4 parts of lactamide 5003 (manufactured by Dainippon Ink and Chemicals, Inc.) were dissolved in 50 parts of methanol and 50 parts of n-butanol, and dip-coated on the support to form an undercoat layer having a thickness of 0.6 μm.

10 parts of a disazo pigment having the following structural formula

[0066]

Embedded image And polyvinyl butyral resin (trade name: S-REC B)
M2 Sekisui Chemical Co., Ltd.) 10 parts with cyclohexanone 1
The mixture was dispersed for 10 hours in a sand mill together with 20 parts. 30 parts of methyl ethyl ketone was added to the dispersion and applied onto the undercoat layer to form a 0.15 μm thick charge generation layer.

10 parts of a polycarbonate Z resin having a weight average molecular weight of 120,000 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was prepared, and a hydrazone compound having the following structural formula was prepared.

[0068]

Embedded image It was dissolved in 80 parts of monochlorobenzene together with 10 parts. This was applied on the charge generation layer to form a charge transport layer having a thickness of 16 μm. 1 was produced.

Next, 100 parts by weight of chloroprene rubber and 5 parts by weight of conductive carbon are melted and kneaded.
It was molded to have a diameter of 20 × 240 mm through a stainless steel shaft of 2 mm, 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 was 3 × 10 ^{4 when} measured in an environment at a temperature of 22 ° C. and a humidity of 60%.
Ωcm.

Next, 3 parts by weight of LM type graphite carbon fiber (diameter 2 μm, length 200 μm) and 7 parts by weight of a nylon copolymer (CM8000 Toray) were added to 90 parts by weight of ethanol and dispersed by a ball mill.

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

As shown in FIG. 4, this charging member is attached in place of a primary developing type copying machine PC-20 (manufactured by Canon) in place of a primary corona charger, and is rotated by rotation with an electrophotographic photosensitive member. 750V and AC peak-to-peak voltage 15
00V was superimposed, and the dark potential and the bright potential of the electrophotographic photosensitive member were measured and the image was examined. The results are shown in Table 1.

Further, 10,000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

Example 2 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, LM type graphite carbon fiber (diameter 4μ,
500 μm) 4 parts by weight and methoxymethylated nylon
6 (methoxymethylation ratio 28%) 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 having a thickness of 200 μm after drying. This was evaluated in the same manner as in Example 1 and shown in Table 1.

Example 3 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, HS type carbon fiber (diameter 4 μm, length 1000 μm)
m) 2 parts by weight and 8 parts by weight of polyvinyl butyral (BX-1 Sekisui Chemical) were added to 90 parts by weight of ethanol, and dispersed in a ball mill.

Dip coating was performed on the conductive elastic layer of the charging member, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member. This was evaluated in the same manner as in Example 1 and shown in Table 1.

Example 4 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, HM type carbon fiber (diameter 8 μm, length 5000 μm)
m) 5 parts by weight and a vinyl chloride / vinyl acetate copolymer (VMCH, UC
C) (5 parts by weight) was added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

Dip coating was performed on the conductive elastic layer of the charging member, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member. This was evaluated in the same manner as in Example 1 and shown in Table 1.

Comparative Example 1 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, conductive carbon (Conductex C-900)
3 parts by weight (made by Columbian Carbon Co.) and 7 parts by weight of a nylon copolymer (CM8000 Toray) were added to 90 parts by weight of ethanol, followed by ball mill dispersion.

A roller-shaped charging member was manufactured by dip coating on the conductive elastic layer of the charging member and providing a resin layer having a thickness of 200 μm after drying. This was evaluated for the initial potential measurement and the image in the same manner as in Example 1. The results are shown in Table 1. Further, 5000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

Comparative Example 2 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, 2 parts by weight of a polytetrafluoroethylene fine powder (manufactured by Lubron L-2 Daikin) and a nylon copolymer (C
8 parts by weight (M8000, manufactured by Toray Industries, Inc.) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

On the conductive elastic layer of the charging member, dip coating was performed, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member. This was evaluated in the same manner as in Comparative Example 1 and shown in Table 1.

Comparative Example 3 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, 2 parts by weight of polyvinylidene fluoride fine powder (Kainer Tomoe Kogyo) and polyvinyl butyral (Eslec B)
X-1 manufactured by Sekisui Chemical Co., Ltd.)
In addition to parts by weight, the mixture was dispersed in a ball mill.

Dip coating was performed on the conductive elastic layer of the charging member, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped charging member. This was evaluated in the same manner as in Comparative Example 1 and shown in Table 1.

Comparative Example 4 In the same manner as in Example 1, a conductive elastic layer of a charging member was prepared. Next, 10 parts by weight of polyvinyl butyral (Eslek BX-1 Sekisui Chemical) is dissolved in 90 parts by weight of methyl ethyl ketone, dip-coated on the conductive elastic layer of the charging member, and dried to form a 200 μm-thick resin layer. To manufacture a roller-shaped charging member. This was evaluated in the same manner as in Comparative Example 1 and shown in Table 1.

As can be seen from a comparison between Examples 1, 2, 3, and 4 and Comparative Examples 1 and 4, in the present invention, filming due to toner contamination of the charging member during durability can be prevented, and image defects can be prevented. .

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

In Comparative Examples 2 and 3, the lubricating additive of the resin was used, and the charging performance was degraded at the time of durability, and the density was reduced. Next, characteristics as a transfer charger were examined.

Example 5 A photoconductor was prepared in the same manner as in Example 1. Next, 100 parts by weight of chloroprene rubber is melt-kneaded with 5 parts by weight of conductive carbon, and the center is formed through a stainless steel shaft of φ8 × 260 mm to form φ30 × 240 mm to provide a conductive elastic layer of a roller-shaped charging member. Was.

The volume resistance of the transfer charging member was set at a temperature of 22.
It is 4 × 10 ⁴ Ωcm when measured in an environment at a temperature of 60 ° C. and a humidity of 60%.

Next, 4 parts by weight of LM type graphite carbon fiber (diameter 2 μm, length 200 μm) and 6 parts by weight of a nylon copolymer (CM8000 Toray) are dissolved in ethanol 90 parts by weight, and the conductivity of the transfer charging member is reduced. Dip coating on the elastic layer, providing a resin layer with a thickness of 100 μm after drying,
A roller-shaped transfer charging member was manufactured. A resin layer was similarly provided on the aluminum sheet, and the volume resistance was measured.

This transfer charging member was attached in place of the transfer corona charger of the forward development type copying machine PC-20 (manufactured by Canon) as shown in FIG. 5, and a transfer charge of -500 V was applied. The condition of the members was studied. The results are shown in Table 2. Further, 10,000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

Example 6 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, LM type graphite carbon fiber (diameter 4μ)
m, 500 μm in length) 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.

Dip coating was performed on the conductive elastic layer of the transfer charging member, and after drying, a resin layer having a thickness of 100 μm was provided to manufacture a roller-shaped transfer charging member. Example 5
Table 2 shows the evaluation results.

Example 7 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, HS type carbon fiber (diameter 4 μm, length 1000)
μm) 3 parts by weight and 7 parts by weight of polyvinyl butyral (BX-1 Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone, followed by ball mill dispersion.

Dip coating was performed on the conductive elastic layer of the transfer charging member, and after drying, a resin layer having a thickness of 100 μm was provided to manufacture a roller-shaped transfer charging member. Example 5
Table 2 shows the evaluation results.

Example 8 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, HM type carbon fiber (diameter 8 μm, length 500 μm)
m) 5 parts by weight and a vinyl chloride / vinyl acetate copolymer (VMCH, UC
C) 5 parts by weight were added to 90 parts by weight of methyl ethyl ketone, and the mixture was dispersed in a ball mill.

The transfer charging member was dip-coated on the conductive elastic layer, dried and then provided with a resin layer having a thickness of 100 μm to manufacture a roller-shaped transfer charging member. Example 5
Table 2 shows the evaluation results.

Comparative Example 5 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, conductive carbon (Conductex C-90)
0 parts by weight of Columbian Carbon Co., Ltd.) and 7 parts by weight of a nylon copolymer (CM8000 Toray) were added to 90 parts by weight of ethanol and dispersed by a ball mill.

Dip coating was performed on the conductive elastic layer of the transfer charging member, and after drying, a resin layer having a thickness of 200 μm was provided to produce a roller-shaped transfer charging member.

This was measured in the same manner as in Example 5 except for the initial potential measurement.
And the images were evaluated and are shown in Table 2. Further, 5000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

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

A transfer-charging member having a roller shape was manufactured by dip-coating the conductive elastic layer of the transfer-charging member and providing a resin layer having a thickness of 200 μm after drying. This was compared with Comparative Example 5
Table 2 shows the evaluation results.

Comparative Example 7 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, 2 parts by weight of polyvinylidene fluoride fine powder (Kainer Tomoe Kogyo) and polyvinyl butyral (Eslec B)
X-1 manufactured by Sekisui Chemical Co., Ltd.)
In addition to parts by weight, the mixture was dispersed in a ball mill.

The transfer charging member was manufactured by 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-shaped transfer charging member. This was compared with Comparative Example 5
Table 2 shows the evaluation results.

Comparative Example 8 In the same manner as in Example 5, a conductive elastic layer of a transfer charging member was prepared. Next, polyvinyl butyral (Eslec BX-1)
(Sekisui Chemical) 10 parts by weight dissolved in 90 parts by weight of methyl ethyl ketone, dip-coated on the conductive elastic layer of the transfer charging member, provided with a 200 μm-thick resin layer after drying, Was manufactured. This was evaluated in the same manner as in Comparative Example 5 and shown in Table 2.

As can be seen by comparing Examples 5, 6, 7, and 8 with Comparative Examples 5 and 8, in the present invention, filming due to toner contamination of the charging member at the time of durability is prevented, and the density of the charging member is reduced, and whitening is prevented. The occurrence of image defects 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 fusion between the charging member and the photoreceptor and to suppress the occurrence of a horizontal stripe defect image.

In Comparative Examples 6 and 7, a resin lubricity additive was used, and the transfer performance was deteriorated during durability, resulting in a decrease in density. Next, the characteristics as a static eliminator were examined.

Example 9 A photoconductor was prepared in the same manner as in Example 1. Next, 100 parts by weight of chloroprene rubber and 5 parts by weight of conductive carbon are melted and kneaded, and molded on a 2 mm × 260 mm stainless plate at the center so as to have a free length of 10 mm × 240 mm as shown in FIG. The conductive elastic layer of the member was provided. The volume resistance of the charge removing member is 4 × 10 ⁴ Ωcm when measured in an environment at a temperature of 22 ° C. and a humidity of 60%.

Next, 3 parts by weight of LM type graphite carbon fiber (diameter 2 μm, length 200 μm) and 7 parts by weight of a nylon copolymer (CM8000 Toray) were added to 90 parts by weight of ethanol, and dispersed by a ball mill.

Dip coating was performed on the conductive elastic layer of the charge-eliminating member, and after drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped charge-eliminating member as shown in FIG. A resin layer was similarly provided on the aluminum sheet, and the volume resistance was measured.

The charge removing member is attached in place of the pre-exposure charge remover of the positive development type copying machine PC-20 (manufactured by Canon Inc.) as shown in FIG.
V was applied to examine the state of the image and the charge removing member.
The results are shown in Table 3. Further, 10,000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

Example 10 In the same manner as in Example 9, a conductive elastic layer of a charge removing member was prepared. Next, LM type graphite carbon fiber (diameter 4μ)
m, 500 μm in length) 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 dispersed in a ball mill.

Dip coating was performed on the conductive elastic layer of the charge-eliminating member, and after drying, a resin layer having a thickness of 100 μm was provided to manufacture a blade-shaped charge-eliminating member. Example 9
Table 3 shows the results.

Example 11 In the same manner as in Example 9, a conductive elastic layer of a member for discharging and charging was prepared. Next, HS type carbon fiber (diameter 4 μm, length 1000)
2 μm) and 8 parts by weight of polyvinyl butyral (BX-1 Sekisui Chemical) were added to 90 parts by weight of methyl ethyl ketone, and the mixture was dispersed in a ball mill.

Dip coating was performed on the conductive elastic layer of the charge removing member, and after drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped transfer charge member. Example 9
Table 3 shows the results.

Example 12 In the same manner as in Example 9, a conductive elastic layer of a charge removing member was prepared. Next, HM type carbon fiber (diameter 8 μm, length 5000)
μm) 4 parts by weight and a polyvinyl chloride / vinyl acetate copolymer (VMCH, U
6 parts by weight (manufactured by CC) were added to 90 parts by weight of methyl ethyl ketone and dispersed in a ball mill.

On the conductive elastic layer of the charge-eliminating member, dip coating was performed, and after drying, a resin layer having a thickness of 100 μm was provided to manufacture a blade-shaped charge-eliminating member. Example 9
Table 3 shows the results.

Comparative Example 9 In the same manner as in Example 9, a conductive elastic layer of a member for discharging and charging was prepared. Next, conductive carbon (Conductex C-90)
0 parts by weight of Columbian Carbon) and 7 parts by weight of a nylon copolymer (CM8000 Toray) were added to 90 parts by weight of ethanol and dispersed in a ball mill. This was subjected to initial potential measurement and image evaluation in the same manner as in Example 9, and the results are shown in Table 3. Further, 5000 images were repeatedly taken, and the potential measurement and the image after durability were examined.

Comparative Example 10 In the same manner as in Example 9, a conductive elastic layer of a member for discharging and charging was prepared. Next, 2 parts by weight of polytetrafluoroethylene fine powder (manufactured by Lubron L-2 Daikin) and 8 parts by weight of a nylon copolymer (manufactured by CM8000 Toray) were added to 90 parts by weight of ethanol, followed by ball mill dispersion.

On the conductive elastic layer of the charge-eliminating member, dip coating was performed, and after drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped charge-eliminating member. This was compared with Comparative Example 9
Table 3 shows the results.

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

On the conductive elastic layer of the charge-eliminating member, dip coating was performed, and after drying, a resin layer having a thickness of 100 μm was provided to produce a blade-shaped charge-eliminating member. This was compared with Comparative Example 9
Table 3 shows the results.

Comparative Example 12 In the same manner as in Example 9, a conductive elastic layer of a member for discharging and charging was prepared. Next, polyvinyl butyral (Eslec BX-1)
10 parts by weight of Sekisui Chemical Co., Ltd. were dissolved in 90 parts by weight of methyl ethyl ketone, dip-coated on the conductive elastic layer of the member for static elimination and charging, and dried to form a resin layer having a thickness of 100 μm. Components were manufactured. This was evaluated in the same manner as in Comparative Example 9 and shown in Table 3.

Examples 9, 10, 11, 12 and Comparative Example 9,
As can be seen from a comparison of No. 12, in the present invention, filming due to toner contamination of the charging member during durability can be prevented, the residual potential can be suppressed, and occurrence of background fog can be prevented. Further, as can be seen by comparing Examples 9, 10, 11, and 12 with Comparative Example 12, it is possible to prevent fusion between the charging member and the photosensitive member and suppress occurrence of a horizontal stripe defect image. In Comparative Examples 10 and 11, the lubricating additive of the resin was used, and the static elimination performance was deteriorated at the time of durability, and a vertical streak defect image was generated.

[0129]

[Table 1]

[0130]

[Table 2]

[0131]

[Table 3] Resistance measurement method .

The resistance of the conductive elastic layer was measured by the method shown in FIG. 9: a charging member was sandwiched between conductive frames, and a DC voltage of 1 kV was applied to the core and the frame to measure the resistance. Find the resistance value.

In FIG. 9, reference numeral 201 denotes a metal core of a charging member;
2 is a conductive elastic layer of the charging member, 203 is a frame type, 204 is a conducting wire, and 205 is an ohmmeter.

The volume resistance of the resin layer is determined by providing a resin layer material on an aluminum sheet and applying a DC voltage of 1 kV with a resistance meter (16008A) manufactured by Hewlett-Packard Company to determine the volume resistance value.

[0135]

As described above, the charging member of the present invention has a low adhesion to an electrophotographic photosensitive member by providing a resin layer containing carbon fibers on a conductive elastic layer. And it has good flexibility, so when it is applied to electrophotographic devices or copiers, there is little toner contamination,
Since the volume resistance of the resin layer is small even under low temperature and low humidity,
Gives high quality images. It is also excellent in durability and can maintain the above effects for a long time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a roller-shaped charging member according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing another roller-shaped charging member according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a blade-shaped charging member according to still another embodiment of the present invention.

FIG. 4 is a schematic longitudinal sectional view of an electrophotographic apparatus provided with the charging member of the present invention shown in FIG. 1 or FIG.

FIG. 5 is a schematic longitudinal sectional view of an electrophotographic apparatus provided with the charging member of the present invention shown in FIG. 1 or 2 for transfer charging.

6 is a schematic longitudinal sectional view of a positive development type copying machine provided with the charging member of FIG.

FIG. 7 is a schematic longitudinal sectional view of a general transfer type electrophotographic apparatus using a drum type photoreceptor.

FIG. 8 is a block diagram showing the configuration of the device shown in FIG. 7;

FIG. 9 is an explanatory diagram showing a method for determining the volume resistance of a conductive elastic layer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 conductive elastic layer 3 resin layer 4 protective layer 5 particles 6 primary charging member 7 image exposure means 8 developing means 9 transfer charging means 10 cleaning means 11 pre-exposure means 12 photoreceptor 13 transferred member 14 primary Corona charger for charging 15, 16 Charging member

Claims (4)

(57) [Claims] 1. A charging member comprising a conductive support and a conductive elastic body provided thereon, wherein a resin layer containing carbon fibers is provided on the conductive elastic body. Charging member. 2. The charging member according to claim 1, wherein a protective layer for protecting the resin layer is provided as an outermost layer. 3. The charging member according to claim 1, wherein the resin layer has a volume resistivity in a range of 10 ⁶ Ω · cm to 10 ¹² Ω · cm. 4. The charging member according to claim 1, wherein the thickness of the resin layer is in a range of 5 to 500 μm.