JPH04306676A - 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 of excellent durability. CONSTITUTION:A member for electrification is used for primary electrification, transfer electrification, and for elimination electrification in electron photographing method, and is formed out of a conductive supporting material 1 and a conductive elastic material 2 provided thereon, while a ZnO whisker is characteristically included in the conductive elastic material 2. The member has good flexibility, and when this is used for electron photographing device or for a copying machine, noise is at low level, and a high quality image is obtained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a direct charging member,
In particular, the present invention relates to a charging member used for primary charging, transfer charging, and neutralizing charging in electrophotography.

0002

2. Description of the Related Art Charging processes in electrophotographic processes using electrophotographic photoreceptors have heretofore mostly been carried out using corona generated by applying a high voltage (5 to 8 kV DC) to a metal wire. 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.
Dirt on the wires affected the image quality, causing problems such as white spots and black lines in 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 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
The reversal development method produces a speckled black dot image corresponding to spotty charging unevenness, and the regular image method produces a speckled white dot image, 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.

Furthermore, due to the hardness of the charging member, the frequency of the superimposed alternating current voltage causes the charging member to vibrate, and this vibration is transmitted to the photoreceptor that is in close contact with it, causing unpleasant noise to be generated from the photoreceptor. There were also points.

The present invention has been made to solve the above-mentioned problems with conventional charging members, and is capable of stably supplying high-quality images without spotty fog caused by non-uniform charging. To provide a charging member that can be used for charging 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 the conductive elastic body contains ZnO whiskers. It is characterized by

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

The charging member of the present invention is in the form of a roller, for example 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. . Further, as shown in FIG. 2, a resin layer 3 may be provided on the conductive elastic layer 2. Alternatively, the charging member of the present invention may have a conductive elastic layer 2 supported on a conductive support 1 in the form of a flat plate, as shown in FIG. A resin layer 3 may be provided on the layer 2. Furthermore, as shown in FIG. 5, the charging member of the present invention may be one in which an endless belt-shaped conductive elastic layer 2 is supported on a conductive support 1 in the form of a pair of parallel shafts. However, the conductive elastic layer 2 is made of binder resin,
It is composed of a material mixed with ZnO whiskers.

That is, since the charging member of the present invention has a resin layer in which ZnO whiskers are mixed in the conductive elastic layer, it has excellent flexibility, provides high-quality images, has low charging noise, and has excellent durability. It can be advantageously used as a certain charging member.

A further object of the present invention is to provide a charging member that prevents unpleasant noises caused by vibrations caused by applied alternating current voltage;
An object of the present invention is to provide a contact charging device and an electrophotographic device.

On the other hand, since conventional charging members are composed of conductive carbon, metal powder, or metal oxide powder as a conductive material, the resistance of the conductive elastic layer may be uneven, or the resistance may be lowered. Therefore, when the content of the conductive material is increased, the surface becomes hard and wrinkles occur, resulting in image defects. According to the invention, all such drawbacks are eliminated.

The structure of the charging member of the present invention will be explained below.

[0015] As the conductive substrate, metals such as iron, copper, and stainless steel, conductive resins such as carbon-dispersed resins, metal particle-dispersed resins, etc. can be used, and the shape thereof can be rod-like, plate-like, etc. can.

The conductive elastic layer can be formed by dispersing 1% to 30% by weight of ZnO askers in an elastic body such as rubber, sponge, or thermoplastic elastomer.

The elastic body may be rubber or sponge such as chloroprene rubber, isoprene rubber, EPDM rubber, polyurethane rubber, epoxy rubber, butyl rubber, styrene-butadiene thermoplastic elastomer, polyurethane thermoplastic elastomer, polyester thermoplastic elastomer, or ethylene. - Thermoplastic elastomers such as vinyl acetate thermoplastic elastomers can be used.

The hardness of the conductive elastic layer is determined according to JIS K-1 from the viewpoint of adhesion to the charged object due to its flexibility and vibration absorption properties.
It is preferable that the rubber hardness is 30 degrees or less as measured by a JIS-A type measuring device (trade name "Techlock GS-706", manufactured by Techlock Co., Ltd.) in accordance with the measurement method of 6301. Also,
From the above point, the thickness of the conductive elastic layer is preferably 1.5 mm or more, particularly 2 mm or more.

The ZnO whiskers mixed in the binder resin are tetrapod-shaped or needle-shaped crystals, and 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 produced by heat treating Zn powder in the presence of oxygen. Tetrapot-shaped ZnO whiskers commercially available from Matsushita Industrial Equipment Co., Ltd.
"Panatetra" etc. are used.

[0020] In the case of needle-like, tetrapod-shaped ZnO
Mechanically crushed whiskers are used.

The volume resistivity of the conductive elastic layer 2 of the present invention is 100 to 1011 Ω·cm, particularly 102 to 10
A range of 10 Ω·cm is preferable.

The resistance layer is formed to have a higher resistance than the conductive layer, and has a volume resistivity of 106 to 1012Ω.
・cm, preferably 10 7 to 10 11 Ω·cm, and semiconductive resin, conductive particle-dispersed insulating resin, etc. can be used. Semiconductive resins include ethyl cellulose, nitrocellulose, methoxymethylated nylon,
Examples include resins such as ethoxymethylated nylon, copolymerized nylon, polyvinylpyrrolidone, casein, and mixtures of these resins. The conductive particle-dispersed insulating resin is made by dispersing a small amount of conductive particles such as carbon, aluminum, indium oxide, titanium oxide, etc. in an insulating resin such as urethane, polyester, vinyl acetate-vinyl chloride copolymer, polymethacrylic acid, etc. For example, the resistance can be adjusted by adjusting the resistance. Among these, in consideration of the homogeneity and smoothness of the surface of the resistance layer, semiconductive resins formed from resin alone are preferable.

In addition, the thickness of the resistance layer is 1 μm from the viewpoint of charging property.
m to 500 μm, particularly preferably 50 μm to 200 μm.

[0024] In addition to these layers, other layers such as an adhesive layer for improving the adhesion of each layer may be provided.

The charging member according to the present invention is manufactured, for example, as follows.

First, a metal rod is prepared as a conductive base of a charging member. The material for the conductive elastic layer is formed on a metal rod by melt molding, injection molding, dip coating, spray coating, etc. to provide the conductive elastic layer.

A material for the resistive layer is applied onto the conductive layer by dip coating, spray coating, gravure coating, etc. to form a resistive layer.

Furthermore, the charging member may have a protective layer for protecting the resin layer 3 as the outermost layer. This protective layer may contain particles such as conductive particles for controlling conductivity or insoluble resin particles for controlling surface roughness.

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

The structure of the present invention makes it possible to control both flexibility and conductivity, thus solving the problem of conventional conductive rubbers that are difficult to soften. The charging member of the present invention having such a structure maintains sufficient conductivity due to the conductive elastic layer, and can obtain uniform adhesion to the photoconductor due to the flexibility and surface smoothness of the resistance layer. Therefore, uniform charging without uneven charging can be performed.

Furthermore, the charging member of the present invention can prevent or reduce noise caused by alternating current waves of alternating current voltage applied and superimposed from an external power source. That is, the charging member to which a direct current voltage and an alternating current voltage are applied from the outside in a superimposed manner absorbs vibrations caused by the applied pulsating voltage due to the flexibility of the elastic layer between the conductive base and the conductive layer. Therefore, vibrations are not transmitted to the photoreceptor that is in contact with the charging member, so that unpleasant noise from the photoreceptor and the inside of the photoreceptor accompanying the vibration can be prevented or reduced.

Furthermore, by providing a resistive layer, dielectric breakdown caused by internal defects in the photoreceptor can be prevented, and even if there is a pinhole, white spots extending in the longitudinal direction of the contact area and reverse development can be prevented in the normal development method. In this method, image defects such as black lines can be prevented and excellent images can be obtained.

In contrast, by creating a charging member in which a conductive elastic layer and a resistance layer are provided on a conductive base,
Since the contact portion with the photoreceptor is a resistive layer, charges are dispersed and dielectric breakdown at defective portions can be prevented. Also,
Even if conduction occurs at the pinhole portion of the photoreceptor, the presence of the resistive layer maintains resistance to the applied voltage, so no load is applied to the external power supply section, and voltage drop can be prevented. Therefore, image defects such as white spots or black lines caused by pinholes can be prevented.

The electrophotographic photoreceptor basically has a structure in which a photosensitive layer is provided on a conductive support. As the conductive support, materials whose support itself is conductive can be used, such as aluminum, aluminum alloy, stainless steel, chromium, titanium, etc. 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.

[0035] 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 generating layer may be formed by depositing one or more charge generating materials such as azo pigments, quinone pigments, quinone anine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, and quinacridine pigments, or 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. In this apparatus, a primary charging member 6, an image exposure means 7, a developing means 8, a transfer charging means 9, a cleaning means 10, and a pre-exposure means 11 are arranged on the circumferential surface of a drum-shaped electrophotographic photoreceptor 12. There is.

A voltage (for example, 200
DC voltage between V and 2000V and peak-to-peak voltage 400V
A pulsating current voltage superimposed with an AC voltage of 0 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, by attaching the developer in the developing means 8 to the photoreceptor, the electrostatic latent image on the photoreceptor is developed (visualized),
Further, the developer on the photoreceptor is transferred to a transfer member 13 such as paper by a transfer charging means 9, and the developer remaining on the photoreceptor without being transferred to the paper during transfer is collected by a cleaning means 10.

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.

A voltage (for example, a DC voltage of 4
00 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.

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.

[0055] The method of installing the charging member in contact with the photoreceptor in the present invention is not limited to a specific 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 device, 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 step by step, or if DC and AC are superimposed on each other, the voltage can be applied in the order of DC → AC or AC → DC.

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.

[0058] 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.

[0060] When used for static electricity removal charging, it is necessary to apply only an alternating current voltage.

Furthermore, in the present invention, processes such as image exposure, development, and cleaning can be performed using any method known in the field of electrostatic photography, and are 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. 9 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 between the photoreceptor 101 and the transfer means 105 from a paper feed section (not shown) by 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 to the outside of 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 used repeatedly 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 device unit, and configured to be detachable using a guide means such as a rail on the main body of the device. At this time,
The above device unit may be configured with 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. 10 is a block diagram showing an example of this case.

The controller 111 controls the image reading section 110 and the 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. Printer controller 1
18 controls a 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 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 receiving the next page while the printer 119 is recording.

[0072] As described above, images are received and recorded.

Examples of the present invention are shown below.

[0074]

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

[0075] 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
077]

embedded image and 10 parts of polyvinyl butyral resin (trade name: S-LEC BM2 manufactured by Sekisui Chemical Co., Ltd.) were dispersed together with 120 parts of cyclohexanone in a sand mill 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.

[0079]

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, 10 parts by weight of tetrapod-shaped ZnO whiskers (length 10 μm) were melt-kneaded with 100 parts by weight of chloroprene rubber, and a stainless steel shaft of φ8×260 mm was passed through the center and formed into a shape of φ20×240 mm. A conductive elastic layer of a charging member was provided.

The volume resistivity of the conductive elastic layer of this charging member is 3×10 8 when measured in an environment with a temperature of 22° C. and a humidity of 60%.
It is Ωcm.

As shown in FIG. 6, this charging member was attached in place of the primary corona charger of a normal development type copying machine PC-20 (manufactured by Canon), and rotated in accordance with the electrophotographic photoreceptor, so that the primary charging voltage was set to a DC voltage of - 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 image and noise were examined. The results are shown in Table 1.

Example 2 A charging member was molded in the same manner as in Example 1, except that 8 parts by weight of tetrapod-shaped ZnO whiskers (length 30 μm) were used instead of the ZnO whiskers used in Example 1. The volume resistance of the conductive member of this charging member is determined at a temperature of 22°C.
, when measured in an environment with 60% humidity, it is 6 x 10 8 Ω·cm. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Example 3 The tetrapod-shaped ZnO whiskers used in Example 1 (
A conductive elastic layer of a roller-shaped charging member was provided in the same manner as in Example 1, except that 15 parts by weight of a material having a length of 10 μm was used. The volume resistance of the conductive elastic layer of this charging member is determined at a temperature of 22
When measured in an environment of ℃ and 60% humidity, it is 6 x 106 Ωcm.

Next, N-methoxymethylated nylon-6 (
10 parts by weight of methoxymethylation rate 30%) and 9 parts by weight of methanol
It was dissolved in 0 parts by weight and applied by dip coating on the conductive elastic layer, and after drying, the film thickness was set to 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistivity of the surface resistance layer is 5×10 9 Ω·cm when measured in an environment with a temperature of 22° C. and a humidity of 60%. This charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Example 4 The tetrapod-shaped ZnO whiskers used in Example 1 (
A conductive elastic layer of a roller-shaped charging member was provided in the same manner as in Example 1, except that 15 parts by weight of a material having a length of 10 μm was used. The volume resistance of the conductive elastic layer of this charging member is determined at a temperature of 22
When measured in an environment of ℃ and 60% humidity, it is 6 x 106 Ωcm.

Next, 1 part by weight of indium oxide powder (manufactured by Dowa Chemical Co., Ltd.) and 19 parts by weight of nitrocellulose were mixed with 70 parts by weight of methanol, dispersed in a ball mill, applied by dip coating onto the conductive elastic layer, and dried. After that, a surface resistance layer was provided with a film thickness of 200 μm. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer is 5 x 108 when measured at a temperature of 22°C and a humidity of 60%.
It is Ωcm. This charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Comparative Example 1 A charging member was molded in the same manner as in Example 1, except that 10 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 1. did. The volume resistivity of the conductive elastic layer of this charging member is 6×10 10 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Comparative Example 2 A charging member was used in the same manner as in Example 1, except that 20 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 1. Molded. The volume resistivity of the conductive elastic layer of this charging member is 3×10 6 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Comparative Example 3 A conductive elastic layer of a charging member was molded in the same manner as in Comparative Example 2. Next, 10 parts by weight of N-methoxymethylated nylon-6 (methoxymethylation rate 30%) was dissolved in 90 parts by weight of methanol, and the solution was dip coated onto the conductive elastic layer, and after drying,
A surface resistance layer was provided with a film thickness of 200 μm. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistivity of the surface resistance layer is 5×10 9 Ω·cm when measured in an environment with a temperature of 22° C. and a humidity of 60%. This charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Comparative Example 4 A conductive elastic layer of a charging member was molded in the same manner as in Comparative Example 2. Next, 1 part by weight of indium oxide powder (manufactured by Dowa Chemical Co., Ltd.) and 19 parts by weight of nitrocellulose were mixed with 70 parts by weight of methanol, dispersed in a ball mill, and dip coated onto the conductive elastic layer. After drying, the film was coated. The thickness was 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer is determined by temperature 2.
When measured in an environment of 2°C and 60% humidity, it is 6 x 108 Ωcm. This charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Potential measurement, images, and noise were examined in the same manner as in Example 1.

Examples 1, 2, 3, 4 and comparative examples 1, 2, 3
, 4, the present invention can prevent the vibration noise of the charging member and prevent the occurrence of image defects. Furthermore, the charging characteristics of the photoreceptor by the charging member are improved.

[0093] Furthermore, even as a single layer, the problems of conventional charging members are solved. Next, we investigated its characteristics as a transfer charger.

Example 5 A photoreceptor was produced in the same manner as in Example 1. 100 parts by weight of styrene-butadiene thermoplastic elastomer (Solprene T, manufactured by Nippon Elastomers) and 10 parts by weight of tetrapod-shaped ZnO whiskers (length 10 μm) are melted and kneaded, and passed through a stainless steel shaft of φ8 x 260 mm into the center to form a diameter of φ30 x 240 mm. A conductive elastic layer of a roller shape transfer charging member was provided. The volume resistivity of the conductive elastic layer of this transfer charging member is 6×10 6 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%.

This transfer charging member was installed in place of the transfer corona charger of a normal development type copying machine PC-20 (manufactured by Canon) as shown in FIG. 7, and 500 V DC was applied for transfer charging, and images and noise were examined. . The results are shown in Table 2.

Example 6 A charging member was molded in the same manner as in Example 5, except that 8 parts by weight of tetrapod ZnO whiskers (length 30 μm) were used instead of the ZnO whiskers used in Example 5. The volume resistance of the conductive member of this transfer charging member is set at a temperature of 22
When measured in an environment of ℃ and 60% humidity, it is 9×10 8 Ω·cm. Images and noise were examined in the same manner as in Example 5.

Example 7 The tetrapod-shaped ZnO whiskers used in Example 5 (
A conductive elastic layer of a roller shape transfer charging member was provided in the same manner as in Example 5, except that 15 parts by weight of the material (length: 10 μm) was used. The volume resistivity of the conductive elastic layer of this transfer charging member was measured at 22°C and 60% humidity, and was 7 x 106Ω.
cm.

Next, N-methoxymethylated nylon-6 (
10 parts by weight of methoxymethylation rate 30%) and 9 parts by weight of methanol
It was dissolved in 0 parts by weight and applied by dip coating on the conductive elastic layer, and after drying, the film thickness was set to 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistivity of the surface resistance layer is 5×10 9 Ω·cm when measured in an environment with a temperature of 22° C. and a humidity of 60%. This transfer charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Images and noise were examined in the same manner as in Example 5.

Example 8 Tetrapot-shaped ZnO whiskers used in Example 5 (
A conductive elastic layer of a roller shape transfer charging member was provided in the same manner as in Example 5, except that 15 parts by weight of the material (length: 10 μm) was used. The volume resistivity of the conductive elastic layer of this transfer charging member was measured at 22°C and 60% humidity, and was 7 x 106Ω.
cm.

Next, 1 part by weight of indium oxide powder (manufactured by Dowa Chemical Co., Ltd.) and 19 parts by weight of nitrocellulose were mixed with 70 parts by weight of methanol, dispersed in a ball mill, applied by dip coating onto the conductive elastic layer, and dried. After that, a surface resistance layer was provided with a film thickness of 200 μm. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer is 6 x 108 when measured at a temperature of 22°C and a humidity of 60%.
It is Ωcm. This transfer charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Images and noise were examined in the same manner as in Example 5.

Comparative Example 5 A transfer charging member was prepared in the same manner as in Example 5, except that 10 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 5. was molded. The volume resistivity of the conductive elastic layer of this transfer charging member is 8×10 10 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%. Images and noise were examined in the same manner as in Example 5.

Comparative Example 6 A transfer charging member was prepared in the same manner as in Example 5, except that 20 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 5. was molded. The volume resistivity of the conductive elastic layer of this transfer charging member is 5×10 6 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%. Images and noise were examined in the same manner as in Example 5.

Comparative Example 7 A conductive elastic layer of a transfer charging member was molded in the same manner as in Comparative Example 2. Next, 10 parts by weight of N-methoxymethylated nylon-6 (methoxymethylation rate: 30%) was dissolved in 90 parts by weight of methanol, and the solution was dip-coated onto the conductive elastic layer, and after drying, the film thickness was reduced to 200 μm. A surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer is measured at a temperature of 22°C and a humidity of 60%.
When measured in this environment, it is 5×109Ω・cm. This transfer charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Images and noise were examined in the same manner as in Example 5.

Comparative Example 8 A conductive elastic layer of a transfer charging member was molded in the same manner as in Comparative Example 2. Next, 1 part by weight of indium oxide powder (manufactured by Dowa Chemical Co., Ltd.) and 19 parts by weight of nitrocellulose were mixed with 70 parts by weight of methanol, dispersed in a ball mill, and dip coated onto the conductive elastic layer. After drying, the film was coated. The thickness was 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. When the volume resistance of the surface resistance layer is measured at a temperature of 22℃ and a humidity of 60%, it is 6 x 108Ω・c.
It is m. This transfer charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Images and noise were examined in the same manner as in Example 5.

[0105] Examples 5, 6, 7, 8 and comparative examples 5, 6, 7
, 8, the present invention can prevent the vibration noise of the charging member and prevent the occurrence of image defects. Furthermore, the transfer characteristics by the transfer charging member are improved.

[0106] Furthermore, even as a single layer, the problems of conventional transfer charging members are solved. Next, we investigated its characteristics as a static eliminator.

Example 9 A photoreceptor was produced in the same manner as in Example 1. 100 parts by weight of chloroprene rubber, tetrapod-shaped ZnO whiskers (
(length 10 μm) was melted and kneaded to form a 2 mm x 26
Free length 10mm x 240m on a 0mm stainless steel plate
m, and a conductive elastic layer of a blade-shaped static elimination/charging member was provided.

[0108] When the volume resistivity of the conductive elastic layer of this charge eliminating static charge member is measured in an environment with a temperature of 22°C and a humidity of 60%, it is 4 × 1.
08Ω·cm.

[0109] As shown in Fig. 8, this charge-eliminating member was installed in place of the pre-exposure charge eliminator of the normal development type copying machine PC-20 (manufactured by Canon), and the charge-eliminating charge was applied at an AC peak-to-peak voltage of 100
0V was applied and residual potential measurements, images and noise were examined. The results are shown in Table 3.

Example 10 An antistatic charging member was molded in the same manner as in Example 9, except that 8 parts by weight of tetrapod-shaped ZnO whiskers (length 30 μm) were used instead of the ZnO whiskers used in Example 9. The volume resistivity of the conductive elastic layer of this static electricity removal charging member was measured at 22°C and 60% humidity, and was 7 x 108Ω.
cm. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Example 11 Tetrapod-shaped ZnO whiskers used in Example 9 (
The conductive elastic layer of the blade-shaped static elimination/charging member was provided in the same manner as in Example 9, except that 15 parts by weight of the material (length: 10 μm) was used. The volume resistivity of the conductive elastic layer of this static electricity removal charging member was measured at 22°C and 60% humidity and was 7 x 106Ω.
cm.

Next, N-methoxymethylated nylon-6 (
10 parts by weight of methoxymethylation rate 30%) and 9 parts by weight of methanol
It was dissolved in 0 parts by weight and applied by dip coating on the conductive elastic layer, and after drying, the film thickness was set to 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistivity of the surface resistance layer is 5×10 9 Ω·cm when measured in an environment with a temperature of 22° C. and a humidity of 60%. This neutralizing and charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Example 12 Tetrapod-shaped ZnO whiskers used in Example 9 (
The conductive elastic layer of the blade-shaped static elimination/charging member was provided in the same manner as in Example 9, except that 15 parts by weight of the material (length: 10 μm) was used. The volume resistivity of the conductive elastic layer of this static electricity removal charging member was measured at 22°C and 60% humidity and was 7 x 106Ω.
cm.

Next, 1 part by weight of indium oxide powder (manufactured by Dowa Chemical Co., Ltd.) and 19 parts by weight of nitrocellulose were mixed with 70 parts by weight of methanol, dispersed in a ball mill, applied by dip coating onto the conductive elastic layer, and dried. After that, a surface resistance layer was provided with a film thickness of 200 μm. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer is 6 x 108 when measured at a temperature of 22°C and a humidity of 60%.
It is Ωcm. This neutralizing and charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Comparative Example 9 A static eliminating charging member was used in the same manner as in Example 9, except that 10 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 9. Molded. The volume resistivity of the electrically conductive elastic layer of this charge-eliminating member is 7×10 10 Ω·cm when measured in an environment of a temperature of 22° C. and a humidity of 60%. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Comparative Example 10 A static eliminating charging member was prepared in the same manner as in Example 9, except that 20 parts by weight of conductive carbon (Conductex C-900, manufactured by Columbia Carbon) was used instead of the ZnO whiskers used in Example 9. was molded. The volume resistivity of the electrically conductive elastic layer of this neutralizing and charging member is 5×10 6 Ω·cm when measured in an environment with a temperature of 22° C. and a humidity of 60%. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Comparative Example 11 In the same manner as in Comparative Example 10, a conductive elastic layer of a static elimination/charging member was molded. Next, 10 parts by weight of N-methoxymethylated nylon-6 (methoxymethylation rate: 30%) was dissolved in 90 parts by weight of methanol, and the solution was dip-coated onto the conductive elastic layer, and after drying, the film thickness was reduced to 200 μm. A surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. The volume resistance of the surface resistance layer was measured at a temperature of 22°C and a humidity of 60°C.
% environment, it is 5×109Ω・cm. This neutralizing and charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

Comparative Example 12 In the same manner as in Comparative Example 10, a conductive elastic layer of a static elimination/charging member was molded. Next, indium oxide powder (manufactured by Dowa Chemical) 1
parts by weight, 19 parts by weight of nitrocellulose and 70 parts by weight of methanol.
The mixture was mixed in parts by weight, dispersed in a ball mill, and dip coated on the conductive elastic layer. After drying, the film thickness was set to 200 μm, and a surface resistance layer was provided. A surface resistance layer was similarly provided on the aluminum sheet, and the volume resistance was measured. When the volume resistance of the surface resistance layer is measured at a temperature of 22°C and a humidity of 60%, it is 6 x 108Ω.
cm. This neutralizing and charging member had a conductive elastic layer and a surface resistance layer provided on a conductive support. Residual potential measurement, images, and noise were examined in the same manner as in Example 9.

[0119] Examples 9, 10, 11, 12 and comparative example 9,
As can be seen from the comparison of Nos. 10, 11, and 12, the present invention can prevent vibration noise of the static eliminating/charging member and prevent image defects from occurring. Furthermore, the static elimination potential characteristics of the static elimination charging member are improved. In addition, even as a single layer, the problems of conventional static eliminating charging members are solved.

[0120]

[Table 1]

[0121]

[Table 2]

[0122]

[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 metal 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 resistance meter (16008A) manufactured by Hewlett-Packard.

[0126]

As explained above, the charging member of the present invention exhibits good flexibility by containing ZnO whiskers in the conductive elastic layer, and when applied to an electrophotographic device or a copying machine, Gives high quality images with less noise.

[Brief explanation of drawings]

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

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

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

FIG. 4 is a longitudinal sectional view showing another blade-shaped charging member according to the present invention.

FIG. 5 is a longitudinal sectional view showing a belt-shaped charging member according to the present invention.

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

FIG. 7 is a schematic vertical sectional view of an electrophotographic apparatus provided with the charging member of the present invention shown in FIGS. 1 to 4 for transfer charging.

8 is a schematic longitudinal sectional view of a normal development type copying machine provided with the charging member of FIG. 5. FIG.

FIG. 9 is a schematic vertical cross-sectional view of a general transfer type electrophotographic apparatus using a drum-type photoreceptor.

FIG. 10 is a block diagram showing the configuration of the device in FIG. 9.

FIG. 11 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 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 Charging member 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 the conductive elastic body contains ZnO whiskers. 2. The charging member according to claim 1, further comprising a resistance layer as an outermost layer on the conductive elastic body. 3. The conductive elastic body is 100 to 1011
The charging member according to claim 1 or 2, having a volume resistivity in the range of Ω·cm. 4. The charging member according to claim 1, wherein the conductive elastic body has a rubber hardness of 30 degrees or less.