JPH04306675A - Member for electrification - Google Patents

Abstract

PURPOSE:To stably supply a high definition image without dotted fogging due to non-uniform electrification, and to obtain a member for electrification, excellent in durability. CONSTITUTION:A member for electrification is used for primary electrification, transfer electrification, and for elimination electrification in electrophotographing method, and is formed of a conductive supporting material 1 and a conductive elastic material 2 provided thereon, while a resin layer 3 including a ZnO whisker is provided on the conductive elastic material 2, which is a characteristic of this device. When the member is used for electrophotographing device or for a copying machine, toner soil is at a low level, and a high quality image is obtained. Durability of retaining this effect for a long time is also obtained.

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 static elimination charging in electrophotography.

0002

2. Description of the Related Art Conventionally, the charging process in an electrophotographic process using an electrophotographic photoreceptor has mostly been performed by applying a high voltage (DC 5 to 8 kV) to a metal wire and using corona generated. However, with this method, when corona occurs, the surface of the photoreceptor is altered by corona products such as ozone and NOx, causing image blurring and deterioration, and wire dirt affects image quality, resulting in white spots and black lines in the image. There were problems such as the occurrence of 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, Japanese Patent Laid-Open Nos. 57-178267 and 1982-10435).
1 Publication, JP-A-58-40566, JP-A-58
-139156, JP-A-58-150975, etc.).

0004

[Problems to be Solved by the Invention] However, even if the photoreceptor is charged by the above-mentioned direct charging method, uniform charging is not achieved over the entire surface of the photoreceptor;
Spot-like charging unevenness cannot be avoided. When photoimage exposure and subsequent processes are applied to a photoconductor with such spotty charging unevenness, the resulting output image is
In the reversal development method, a speckled black dot image corresponding to spotty charging unevenness is produced, and in the normal development method, a speckled white dot image is produced, making it impossible to obtain a high-quality image.

[0005]Also, although there are many proposals for the direct charging method, there is no market experience at all. 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.

[0006] In order to prevent this dielectric breakdown, charging members having a resin layer provided on the surface have also been reported (for example, JP-A-1-205180 and JP-A-1-211779).
Publication No.). 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. In addition, there may be dust on the surface of the charging member.
There is a lot of dust attached, which is the reason why the durability does not improve. In addition, toner that has been poorly cleaned adheres to the charging member and accumulates, causing a filming phenomenon and deteriorating charging performance. The use of resin powder has been considered as a method for making it easier for toner to slide on the surface of the charging member (Japanese Patent Laid-Open No. 1-66673), but due to the insulating properties of the resin, the resin powder itself is not charged. It was supposed to degrade performance.

The present invention has been made to solve the above-mentioned problems with conventional charging members, and is capable of stably producing high-quality images without spotty fog caused by non-uniform charging. It is an object of the present invention to provide a charging member that can be supplied and has excellent durability.

[0008]

[Means for Solving the Problems] The present invention provides a direct charging member comprising a conductive support and a conductive elastic body provided thereon, in which a resin containing ZnO whiskers is placed on the conductive elastic body. It is characterized by having layers.

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, roller-shaped as shown in FIG. 1, and includes a conductive support 1 in the form of a shaft and a conductive elastic layer 2 provided around the support. A resin layer 3 is provided on the conductive elastic layer 2. This resin layer 3 is made of a material in which ZnO whiskers are mixed into a binder resin.

That is, since the charging member of the present invention has the resin layer 3 mixed with ZnO whiskers on the conductive elastic layer 2, it has little adhesion to the electrophotographic photoreceptor and is flexible, so it has high performance. It can be advantageously used as a charging member that provides high-quality images, has little toner staining, has little variation in volume resistivity of the resin layer even under low temperature and low humidity conditions, and is durable.

In contrast, 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, This caused wrinkles on the photoreceptor, resulting in image defects. 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 5 to 500 μm, particularly 20 to 200 μm, although it varies depending on conditions such as the amount of ZnO whiskers mixed in.
A range of is preferred.

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

[0015] The ZnO whiskers mixed into the binder resin are tetrapod-shaped or needle-shaped crystals, the thickness of the whiskers is 0.5 to 5 μm, and the length of the whiskers is preferably 1 to 50 μm. ZnO whiskers are
It is manufactured by heat treating Zn powder in the presence of oxygen. As an example, a tetrapot-shaped ZnO whisker commercially available from Matsushita Industrial Equipment Co., Ltd. under the trade name "Panatedra" may be used.

In the case of needle-shaped crystals, those obtained by mechanically crushing tetrapod-shaped ZnO whiskers are used.

Preferably, the resin layer 3 has a volume resistivity in the range of 10 6 to 10 12 Ω·cm. Also, as stated 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 that is in contact with it. The volume resistivity of the elastic layer 2 is 100 to 1011 Ω·cm, particularly 102
A range of 1010 Ω·cm is preferable. As the elastic layer 2, metals such as aluminum, iron, copper, polyacetylene,
Conductive polymers such as polypyrrole and polythiophene, rubber or insulating resin treated with conductivity with carbon or metal, or insulating resin or rubber such as polycarbonate or polyester whose surface is laminated and coated with a conductive substance such as metal; etc. can be used. Further, the elastic layer 2 may have a multilayer structure in which each layer has a separate function.

[0018] 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 is
A protective layer 4 for protecting the resin layer 3 may be provided 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. Further, as shown in FIG. 3, a conductive elastic layer 2 attached to a flat conductive support 1 is provided.
It may also have a structure in which a resin layer 3 is provided thereon. This resin layer 3 is made of a material in which ZnO whiskers are mixed into a binder resin.

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

[0021] The electrophotographic photoreceptor basically has a structure in which a photosensitive layer is provided on a conductive support. As the conductive support, materials that are conductive themselves such as aluminum, aluminum alloy, stainless steel, chromium, titanium, etc. can be used. In addition, aluminum, aluminum alloy, indium oxide-tin oxide alloy, etc. can be used. The conductive support or plastic has a layer formed by vacuum deposition, a support in which plastic or paper is impregnated with conductive particles (e.g. carbon black, tin oxide particles, etc.) together with a suitable binder, or a conductive binder. Plastic or the like can be used.

[0022] 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 undercoat layer is suitably 5 μm or less, preferably 0.5 to 3 μm. In order for the undercoat layer to exhibit its function, it is preferable 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 generation layer may be 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 quinacridine pigments; Alternatively, it can be formed by dispersing and coating with a suitable binder (or without a binder).

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

The thickness of the charge generation layer is 0.01 to 15 μm,
The thickness 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 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. Examples of organic solvents include alcohols, sulfoxides, ethers, esters, and fats. Group halogenated 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 Mayer-Barkofing 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,
Examples include stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials are 1
It can be used in one species 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, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or a copolymer containing two or more repeating units of these resins, such as styrene-
Examples include butadiene copolymer, styrene-acrylonite copolymer, styrene-maleic acid copolymer, and the like. Also, poly-N-vinylcarbazole,
Organic photoconductive polymers such as polyvinylanthracene and polyvinylpyrene can also be selected.

The thickness of the charge transport layer is 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: It is about 3. The coating method described above can be used for coating.

Furthermore, dyes, pigments, organic charge transport substances, etc. are generally susceptible to stains caused by ultraviolet rays, ozone, oil, etc.
Since it is sensitive to metals, a protective layer may be provided as necessary. In order to form an electrostatic latent image on this protective layer, it is desirable that the surface resistivity is 10 11 Ω or more.

The protective layer of the photoreceptor is made of polyvinyl butyral,
Polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate,
The photosensitive layer can be formed by applying a solution of a resin such as polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer, etc. in a suitable organic solvent onto 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, an image exposure means 7, a developing means 8, and a transfer charging means 9 on the circumferential surface of a drum-shaped electrophotographic photoreceptor 12.
, cleaning means 10, and pre-exposure means 11 are arranged.

A voltage (for example, 200 V) is applied from the outside to the primary charging member 6 placed in contact with the electrophotographic photoreceptor 12.
DC voltage above 2000V and peak-to-peak voltage 4000V
A pulsating current voltage superimposed with an alternating current voltage of V or less is applied to charge the surface of the electrophotographic photoreceptor 12, and the image on the document is exposed to the photoreceptor by the image exposure means 7 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.

Although an image can be formed by such an electrophotographic process, if residual charges remain on the photoreceptor, the photoreceptor is exposed to light by the pre-exposure means 11 before primary charging to eliminate the residual charges. It is better to eliminate 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 corona charger 14 for primary charging, an image exposure means 7, a developing means 8, a charging member 15 for transfer charging, a cleaning means 10, and a pre-exposure means 11 are arranged on the circumferential surface of an electrophotographic photoreceptor 12. There is.

A voltage (for example, DC voltage 40
0 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 elimination charging, it can be applied to, for example, 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 on the circumferential surface of an electrophotographic photoreceptor 12.

Electric charges on the electrophotographic photoreceptor 12 can be removed by applying a voltage (for example, AC peak-to-peak voltage of 500 to 2000 V) to the charging member 16 for charge removal that is placed in contact with the electrophotographic photoreceptor 12 .

The charging member of the present invention can be applied 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 demonstrated.

[0042] The method of installing the charging member in contact with the photoreceptor in the present invention is not limited to a particular method; the charging member may be fixed or moved by rotating in the same direction or opposite direction to the photoreceptor. It can also be used. Furthermore, it is also possible to cause the charging member to function as a developer cleaning device on the photoreceptor.

Regarding the voltage applied to the charging member and the application method in the direct charging of the present invention, it depends on the specifications of each electrophotographic apparatus, but in addition to the method of instantly applying the desired voltage, there is also a method for protecting the photoreceptor. For this purpose, the applied voltage can be increased in stages, or in the case of applying a superimposed alternating current on direct current, the voltage can be applied in the order of direct current → alternating current or alternating current → direct current.

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 the electrophotographic photoreceptor in the image output area.

[0045] When primary charging is applied only with DC voltage,
Unable to charge uniformly.

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

[0047] When used for static elimination charging, it is necessary to apply only an alternating current voltage.

Further, in the present invention, processes such as image exposure, development, and cleaning can be performed using any method known in the field of electrostatic photography, and are limited to specific methods such as the type of developer. It's not a thing. The charging member of the present invention is applicable not only to copiers but also to laser printers and CRTs.
It can also be used in electrophotographic applications such as 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, 1
01 is a drum-type photoreceptor as an image carrier, and a shaft 101
It is rotated at a predetermined circumferential speed in the direction of the arrow around point a. The photoreceptor 101 is charged by the charging means 10 of the present invention during its rotation process.
2, its peripheral surface is uniformly charged to a predetermined positive or negative potential, and then subjected to optical image exposure L (slit exposure, laser beam scanning exposure, etc.) by an image exposure means (not shown) in the exposure section 103. As a result, electrostatic latent images corresponding to the exposed images are sequentially formed on the circumferential surface of the photoreceptor.

The electrostatic latent image is then developed with toner by the developing means 104, and the toner image is transferred by the transfer means 105 from a paper feeding section (not shown) between the photoreceptor 101 and the transfer means 105 due to the rotation of the photoreceptor 101. The images are sequentially transferred onto the surface of the transfer material P that is fed in synchronization. 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 printed out as a copy outside the machine. After the image has been transferred, the surface of the photoreceptor 101 is cleaned by a cleaning means 106 to remove residual toner and 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. Also, the transfer device 1
Corona transfer means for 05 is also 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.

When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L is performed using reflected light or transmitted light from a document, or by converting the document into a signal and scanning the laser beam using this signal. , driving a light emitting diode array, or driving a liquid crystal shutter array.

Furthermore, when used as a facsimile printer, the optical image exposure L is exposure for printing received data. FIG. 8 is a block diagram showing an example of this case. A controller 111 controls an image reading section 110 and a printer 119. The entire controller 111 is controlled by a CPU 117. 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. 1
14 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 decodes the image information and sequentially stores it in the image memory 116. Stored. When the image of at least one page is stored in the memory 116, the image of that page is recorded. CPU1
17 reads one page of image information from the memory 116 and sends the decoded one page of image information to the printer controller 118. Upon receiving one page of image information from the CPU 117, the printer controller 118 controls the printer 11 to record the image information of that page.
Control 9. Note that the CPU 117 is connected to the printer 119.
During recording, the next page is being received. As described above, images are received and recorded.

Examples of the present invention are shown below.

[0056]

[Example] Example 1 As a conductive support, 60φ×260 with a wall thickness of 0.5 mm
A mm aluminum cylinder was prepared.

[0057] Copolymerized nylon (product name: CM8000,
Toray Industries, Inc.) Part 4 and Type 8 Nylon (Product name:
4 parts of Laccamide 5003 (manufactured by Dainippon Ink Co., Ltd.) was dissolved in 50 parts of methanol and 50 parts of n-butanol, and the solution was dip coated onto the above support to form a 0.6 μm thick subbing layer.

10 parts of a disazo pigment having the following structural formula,

0
059]

[Chemical formula 1] and polyvinyl butyral resin (product name: S-LEC 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 a hydrazone compound having the following structural formula was prepared.

[0061]

embedded image 10 parts and 80 parts of monochlorobenzene were dissolved. This was applied onto the charge generation layer to form a charge transport layer with a thickness of 16 μm. 1 was manufactured.

Next, 5 parts by weight of conductive carbon was melted and kneaded with 100 parts by weight of chloroprene rubber, and a φ8×260
It was molded into a diameter of 20 mm x 240 mm through a stainless steel shaft of mm, and a conductive elastic layer of a roller-shaped charging member was provided.

The volume resistivity of the conductive elastic layer of this charging member is 3×10 4 when measured in an environment with a temperature of 22° C. and a humidity of 60%.
It is Ωcm.

Next, 4 parts by weight of tetrapod ZnO whiskers (length 10 μm) and 6 parts by weight of nylon copolymer (manufactured by Toray Industries, Ltd., trade name "CM8000") were added to 9 parts by weight of ethanol.
0 parts by weight and dispersed using a propeller stirrer.

A ZnO-containing 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.

As shown in FIG. 4, this charging member is attached in place of the primary corona charger of a normal development type copying machine PC-20 (manufactured by Canon), and is rotated in accordance with the electrophotographic photoreceptor, so that the primary charging voltage is a DC voltage - 750V and AC peak-to-peak voltage 15
00V was superimposed, and the dark potential and bright potential of the electrophotographic photoreceptor were measured and the images were examined. The results are shown in Table 1. Furthermore, 10,000 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, 2 parts by weight of tetrapod ZnO whiskers (length 30 μm) and 8 parts by weight of methoxymethylated nylon-6 (methoxymethylation rate 28%) were added to 90 parts by weight of ethanol, and dispersed with a propeller stirrer. I let it happen.

A ZnO-containing 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, tetrapod-shaped ZnO whiskers (length 30 μm
) was dry-milled in a ball mill to produce acicular ZnO whiskers (
A length of 5 μm) was prepared. This acicular ZnO whisker 4
parts by weight, and 6 parts by weight of polyvinyl butyral (trade name "BX-1" manufactured by Sekisui Chemical Co., Ltd.) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

A ZnO whisker-containing resin layer having a thickness of 200 μm after drying was provided by dip coating on the conductive elastic layer of the charging member to produce a roller-shaped charging member. This was evaluated in the same manner as in Example 1 and is shown in Table 1.

Example 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, 2 parts by weight of the acicular ZnO whiskers produced in Example 3 and the tetrapod ZnO whiskers (length 30 μm) were added.
) 2 parts by weight, and vinyl chloride/vinyl acetate copolymer (
6 parts by weight (manufactured by UCC, trade name "VMCH") were added to 90 parts by weight of methyl ethyl ketone and dispersed using a propeller stirrer.

A ZnO whisker-containing 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 1 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, 3 parts by weight of conductive carbon (Conductex C-900 manufactured by Columbia Carbon) and 7 parts by weight of nylon copolymer (CM8000 manufactured by Toray) 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.

[0076] In the same manner as in Example 1, initial potential measurements and images were evaluated, and the results are shown in Table 1. Furthermore, 5,000 images were repeatedly taken, and the potential measurement and images after durability were examined.

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 Daikin) 2 parts by weight and nylon copolymer (CM
8000 manufactured by Toray Industries) was added to 90 parts by weight of ethanol and dispersed in a ball mill.

A roller-shaped charging member was manufactured by dip coating on the conductive elastic layer of the charging member and providing a resin layer with a thickness of 200 μm after drying. This was evaluated in the same manner as Comparative Example 1 and 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 (S-LEC BX-
1 (manufactured by Sekisui Chemical) was 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 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 Comparative Example 1 and shown in Table 1.

Comparative Example 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1. Next, 10 parts by weight of polyvinyl butyral (S-LEC BX-1 Sekisui Chemical) was dissolved in 90 parts by weight of methyl ethyl ketone, and the solution was dip coated onto the conductive elastic layer of the charging member, and after drying, a resin layer with a thickness of 200 μm was formed. and manufactured a roller-shaped charging member. This was evaluated in the same manner as Comparative Example 1 and shown in Table 1.

As can be seen by comparing Examples 1, 2, 3, and 4 with Comparative Examples 1 and 4, the present invention can prevent filming due to toner stains on the charging member during durability and prevent image defects from occurring. .

Furthermore, 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 to suppress the occurrence of horizontal stripe defect images.

In Comparative Examples 2 and 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, 100 parts by weight of chloroprene rubber was melted and kneaded with 5 parts by weight of conductive carbon, passed through a stainless steel shaft of 8 x 260 mm in the center, and formed into a 30 x 240 mm diameter, and a conductive elastic layer of a roller-shaped charging member was provided. Ta.

The volume resistance of this transfer charging member was determined at a temperature of 22
When measured in an environment of ℃ and 60% humidity, it is 4 x 104 Ωcm.

Next, 4 parts by weight of tetrapod ZnO whiskers (length 10 μm) and 6 parts by weight of nylon copolymer (manufactured by Toray Industries, Ltd., trade name "CM8000") were added to 9 parts by weight of ethanol.
0 parts by weight and dispersed using a propeller stirrer. Dip coating this on the conductive elastic layer of the transfer charging member,
A ZnO whisker-containing resin layer having a thickness of 100 μm after drying 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. The condition of the parts was examined. The results are shown in Table 2. Furthermore, 10,000 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, tetrapod-shaped ZnO whiskers (length 30
μm) 2 parts by weight, and methoxymethylated nylon-6
(Methoxymethylation rate 28%) 8 parts by weight to 9 parts by weight of ethanol
0 parts by weight and dispersed using a propeller stirrer.

A ZnO whisker-containing resin layer having a thickness of 100 μm after drying was provided by dip coating on the conductive elastic layer of the transfer charging member to produce a roller-shaped transfer charging member. This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Example 7 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, tetrapod-shaped ZnO whiskers (length 30
μm) was dry-pulverized using a ball mill to produce needle-shaped ZnO whiskers (5 μm in length). 4 parts by weight of this acicular ZnO whisker and 6 parts by weight of polyvinyl butyral (trade name "BX-1" manufactured by Sekisui Chemical Co., Ltd.) were added to 90 parts by weight of ethanol and dispersed using a ball mill.

A ZnO whisker-containing resin layer having a thickness of 100 μm after drying was provided by dip coating on the conductive elastic layer of the transfer charging member to produce a roller-shaped 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, 2 parts by weight of the acicular ZnO whiskers produced in Example 3 and the tetrapod-shaped ZnO whiskers (length 30 parts by weight) were added.
2 parts by weight of vinyl chloride/vinyl acetate copolymer (manufactured by UCC, trade name "VMCH") were added to 90 parts by weight of methyl ethyl ketone and dispersed using a propeller stirrer.

A ZnO whisker-containing resin layer having a thickness of 100 μm after drying was provided by dip coating on the conductive elastic layer of the transfer charging member to produce a roller-shaped transfer charging member. This was evaluated in the same manner as in Example 5 and is shown in Table 2.

Comparative Example 5 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, conductive carbon (Conductex C-90
0 (manufactured by Columbia Carbon) and 7 parts by weight of a nylon copolymer (CM8000 manufactured by Toray Industries) 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 on the conductive elastic layer of the transfer charging member and providing a resin layer with a thickness of 200 μm after drying. Example 5
Initial potential measurements and images were evaluated in the same manner as in Table 2. Furthermore, 5,000 images were repeatedly taken, and the potential measurement and images after durability were examined.

Comparative Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, 2 parts by weight of polytetrafluoroethylene fine powder (Luburon L-2 manufactured by Daikin) and nylon copolymer (
CM8000 (manufactured by Toray)) was 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 on the conductive elastic layer of the transfer charging member and providing a resin layer with a thickness of 200 μm after drying. Comparative example 5
The results are shown in Table 2.

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

A roller-shaped transfer charging member was manufactured by dip coating on the conductive elastic layer of the transfer charging member and providing a resin layer with a thickness of 200 μm after drying. Comparative example 5
The results are shown in Table 2.

Comparative Example 8 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Next, polyvinyl butyral (S-LEC BX-1
Sekisui Chemical) 10 parts by weight was dissolved in 90 parts by weight of methyl ethyl ketone, dip coated on the conductive elastic layer of the transfer charging member, and after drying, a resin layer with a film thickness of 200 μm was provided to form a roller shape transfer charging member. was manufactured. This was evaluated in the same manner as 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, the present invention prevents filming due to toner stains on the charging member during durability, and prevents problems such as thin density and white spots. Image defects can be prevented from occurring.

Furthermore, 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 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, 100 parts by weight of chloroprene rubber and 5 parts by weight of conductive carbon were melt-kneaded and molded onto a stainless steel plate of 2 mm x 260 mm in the center to have a free length of 10 mm x 240 mm as shown in Figure 3, and the blade shape was charged. A conductive elastic layer was provided for the member. The volume resistivity of this charge-eliminating member is 4×10 4 Ωcm when measured in an environment of a temperature of 22° C. and a humidity of 60%.

Next, 4 parts by weight of tetrapod ZnO whiskers (length 10 μm) and 6 parts by weight of nylon copolymer (manufactured by Toray Industries, trade name "CM8000") were mixed with 9 parts by weight of ethanol.
0 parts by weight and dispersed using a propeller stirrer.

[0106] A resin layer having a thickness of 100 μm was applied by dip coating on the conductive elastic layer of the above-mentioned static elimination/charging member, and after drying, 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 static eliminator charging member is installed in place of the pre-exposure static eliminator of the normal development type copying machine PC-20 (manufactured by Canon), and the static eliminator is charged at an AC peak-to-peak voltage of 1000.
V was applied, and the image and the state of the static eliminating charging member were examined. The results are shown in Table 3. Further, 10,000 images were repeatedly taken, and the potential measurement and images after durability were examined.

Example 10 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared. Next, tetrapod-shaped ZnO whiskers (length 30
μm) 2 parts by weight, and methoxymethylated nylon-6
(Methoxymethylation rate 28%) 8 parts by weight to 9 parts by weight of ethanol
0 parts by weight and dispersed using a propeller stirrer.

[0109] A blade-shaped static elimination/charging member was manufactured by dip coating on the conductive elastic layer of the static elimination/charging member and providing a resin layer with a thickness of 100 μm after drying. Example 9
The results were evaluated in the same manner as above and shown in Table 3.

Example 11 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared. Next, tetrapod-shaped ZnO whiskers (length 30
μm) was dry-pulverized using a ball mill to produce needle-shaped ZnO whiskers (5 μm in length). 4 parts by weight of this acicular ZnO whisker and 6 parts by weight of polyvinyl butyral (trade name "BX-1" manufactured by Sekisui Chemical Co., Ltd.) were added to 90 parts by weight of ethanol and dispersed in a ball mill.

[0111] A resin layer having a thickness of 100 μm was provided by dip coating on the conductive elastic layer of the above-mentioned charge-eliminating charging member to produce a blade shape transfer charging member. Example 9
The results were evaluated in the same manner as above and shown in Table 3.

Example 12 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared. Next, 2 parts by weight of the acicular ZnO whiskers produced in Example 3 and the tetrapod-shaped ZnO whiskers (length 30 parts by weight) were added.
2 parts by weight of vinyl chloride/vinyl acetate copolymer (manufactured by UCC, trade name "VMCH") were added to 90 parts by weight of methyl ethyl ketone and dispersed using a propeller stirrer.

[0113] A blade-shaped static elimination/charging member was manufactured by dip coating on the conductive elastic layer of the static elimination/charging member and providing a resin layer with a thickness of 100 μm after drying. Example 9
The results were evaluated in the same manner as above and shown in Table 3.

Comparative Example 9 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared. Next, conductive carbon (Conductex C-90
0 (manufactured by Columbia Carbon) and 7 parts by weight of a nylon copolymer (CM8000 manufactured by Toray Industries) 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. Furthermore, 5,000 images were repeatedly taken, and the potential measurement and images after durability were examined.

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

[0116] A blade-shaped static elimination/charging member was manufactured by dip coating on the conductive elastic layer of the static elimination/charging member and providing a resin layer with a thickness of 100 μm after drying. Comparative Example 9
The results were evaluated in the same manner as above and shown in Table 3.

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

[0118] A blade-shaped static elimination/charging member was manufactured by dip coating on the conductive elastic layer of the static elimination/charging member and providing a resin layer with a thickness of 100 μm after drying. Comparative Example 9
The results were evaluated in the same manner as above and shown in Table 3.

Comparative Example 12 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared. Next, polyvinyl butyral (S-LEC BX-1
Sekisui Chemical) 10 parts by weight of methyl ethyl ketone was dissolved in 90 parts by weight of methyl ethyl ketone, dip coated on the conductive elastic layer of the static elimination charging member, and after drying, a resin layer with a film thickness of 100 μm was provided. The parts were manufactured. This was evaluated in the same manner as Comparative Example 9 and shown in Table 3.

[0120] Examples 9, 10, 11, 12 and comparative example 9,
As can be seen by comparing No. 12, the present invention can prevent filming due to toner stains on the charging member during durability, suppress residual potential, and prevent background fogging. Furthermore, as can be seen by comparing Examples 9, 10, 11, and 12 with Comparative Example 12, it is possible to prevent the charging member from fusing with the photoreceptor and to suppress the occurrence of horizontal streak 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.

[0121]

[Table 1]

[0122]

[Table 2]

[0123]

[Table 3] How to measure resistance.

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

In FIG. 9, 201 is a core bar of a charging member;
2 is a conductive elastic layer of the charging member, 203 is a frame, 204 is a conductive wire, and 205 is a resistance meter.

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

[0127]

As explained above, the charging member of the present invention has a resin layer mixed with ZnO whiskers 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 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.

4 is a schematic vertical sectional view of an electrophotographic apparatus provided with the charging member of the present invention shown in FIG. 1 or 2. FIG.

FIG. 5 is a schematic vertical 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 vertical sectional view of a normal development type copying machine provided with the charging member of FIG. 3; FIG.

FIG. 7 is a schematic vertical cross-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 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]

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 Corona charger for primary charging 15, 16 Charging member

Claims (4)

[Claims] 1. A direct charging member comprising a conductive support and a conductive elastic body provided thereon, characterized in that a resin layer containing ZnO whiskers is provided on the conductive elastic body. Charging member. 2. The charging member according to claim 1, further comprising a protective layer as an outermost layer for protecting the resin layer. 3. The resin layer has a resistance of 10 6 to 10 12 Ω·c.
The charging member according to claim 1 or 2, having a volume resistivity in the range of m. 4. The charging member according to claim 1, wherein the thickness of the resin layer is within a range of 5 to 500 μm.