JPH04299355A - Member for electrification - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 neutralization charging in electrophotography.

0002

2. Description of the Related Art Conventionally, most charging processes in electrophotographic processes using electrophotographic photoreceptors have 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, corona products such as ozone and NOx alter the surface of the photoreceptor, causing image blurring and deterioration, and dirt on the wires affects image quality, resulting in white spots and black lines in the image. There were other problems. On the other hand, the current flowing toward the photoreceptor is
It was only 5 to 30% of the input power, and most of it flowed to the shield plate, making it ineffective as a charging means.

[0003] In order to compensate for these drawbacks, many methods of direct charging have been researched and proposed (Japanese Patent Application Laid-Open No. 57-17
8267, JP 56-104351, JP 58-40566, JP 58-13915
6, JP-A-58-150975, etc.). However, in reality, even if the photoreceptor is charged by the contact charging method as described above, the surface of the photoreceptor is not uniformly charged at each part, and uneven charging occurs. For example, in the reversal development method, even if a process below photoimage exposure is applied to a photoconductor with spotty charging unevenness, the output image will be a black dot image on spots corresponding to the spotty charging unevenness, whereas in the regular development method, the output image will be a black dot image on spots corresponding to the spotty charging unevenness. In contrast to the unevenness, the image becomes a speckled white dot image, making it impossible to obtain a high-quality image.

[0004]Also, although there are many proposals for the direct charging method, there is no market experience at all. Reasons for this include the uniformity of charging and the occurrence of electrical discharge breakdown of the photoreceptor due to direct voltage application. In the case of a cylindrical photoreceptor, for example, in the case of a cylindrical photoreceptor, the discharge dielectric breakdown has a drawback that the entire charge in the axial direction flows to that breakdown point and is no longer charged.

[0005] In order to prevent this dielectric breakdown, a method of forming a resin layer on the surface has also been reported (Japanese Patent Laid-Open No. 1-20
5180, JP-A-1-211779). However, these materials also have large electrical resistance fluctuations under low temperature and low humidity conditions, resulting in unstable charging properties, and when used in contact with an organic photoreceptor, the resin on the surface of the charging member may cause damage to the surface of the organic photoreceptor. It had defects such as being compatible with resin and sticking together.

[0006]

[Problems to be Solved by the Invention] The present invention solves the above-mentioned drawbacks and can stably produce high-quality images without causing spot fog due to non-uniform charging or image defects due to discharge dielectric breakdown of the photoreceptor. The object of the present invention is to provide a charging member that can be supplied.

[0007]

[Means for Solving the Problems] That is, the present invention provides a charging member having a conductive elastic layer on a conductive support.
A charging member characterized by having a polymer layer containing a water-soluble polymer selected from polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyethyleneimine, and starch on the conductive elastic layer. .

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

The charging member of the present invention has a basic configuration in which multiple layers are laminated on a conductive substrate 1, as shown in FIG. The volume electrical resistivity of the polymer layer 3 is preferably in the range of 10 6 to 10 12 Ω·cm. Further, as shown in Japanese Patent Application No. 62-230334, the volume electrical resistivity of the polymer layer 3 is
It is preferable that it is larger than the body electrical volume resistivity of . lower layer 2
The volume electrical resistivity of is 100 to 1011Ω・cm
In particular, a range of 102 to 1010 Ω·cm is preferable. The lower layer 2 is made of metals such as aluminum, iron, copper, etc., conductive polymers such as polyacetylene, polypyrrole, polythiophene, etc., carbon, rubber, insulating resin, polycarbonate, polyester, etc. that have been treated to be conductive by dispersing metals in a matrix. An insulating resin or rubber substrate whose surface is laminated and coated with metal or other conductive material can be used. Further, the lower layer 2 may have a multilayer structure with functions separated as necessary. As the conductive substrate 1, iron, copper, corrosion-resistant steel (stainless steel), etc. can be used.

Furthermore, as shown in FIG. 2, a protective layer 4 may be provided on the surface of the charging member to protect the charging member.

This protective layer is formed of a resin layer, and even if conductive particles are mixed therein to control conductivity, insoluble resin powder 5 is mixed therein to control the surface roughness of the charging member. You may do so.

In the case of a blade-shaped charging member as shown in FIG. 3, a conductive elastic layer is provided as a lower layer 2 on the surface of a conductive sheet metal 1, and a polymer layer 3 is further provided on the surface thereof.

Furthermore, a protective layer may be provided on the polymer layer 3.

Examples of water-soluble polymers used to prepare the charging member of the present invention include: synthetic polymers such as polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and polyethyleneimine; Natural polymers such as starch are used. Further, these water-soluble polymers may form a copolymer with other polymer components.

To form the polymer layer of the present invention, for example, the water-soluble polymer described above is dissolved in a suitable solvent (water, organic solvent, etc.), and the solution is coated on the conductive elastic layer and dried.

The structural formula of the water-soluble polymer used is shown in Table 1.

[0017]

[Table 1] As the starch, α-starch and β-starch are used. Starch can be used by dissolving it in hot water.

When measuring a 10% aqueous solution with a B-type viscometer (No. 2 rotor; 60 rpm), these polymers were
;20°C) having a viscosity of 1 centipoise (cps) to 100 centipoise (cps) is preferably used.

Furthermore, various additives as described below may be added to the polymer layer.

[0020] As the additive, a crosslinking agent consisting of a polyfunctional compound that reacts with active hydrogen in the water-soluble polymer is used. Examples include acid anhydrides such as phthalic anhydride and maleic anhydride, and isocyanates such as tolylene diisocyanate and hexamethylene diisocyanate.

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

The present invention eliminates these drawbacks of conventional charging members and forms high-quality images.

The charging member made of the polymer layer containing the water-soluble polymer of the present invention is less likely to stick to the electrophotographic photoreceptor and is flexible, so it can form high-quality images. In addition, the toner stains less during use, and the volume resistivity of the polymer layer does not vary much even under low temperature and low humidity, so it can be used as a stable charging member. The film thickness of the polymer layer 3 is 5 to 500 μm, preferably 20 to 500 μm.
Select a range of 200 μm.

The shape of the charging member may be either a roller shape or a blade shape, but a roller shape is preferable since uniform charging can be easily achieved.

The electrophotographic photoreceptor basically has a structure in which a photosensitive layer is provided on a conductive support 1. As the conductive support 1, materials whose support itself is conductive, such as aluminum, aluminum alloy, stainless steel, chromium, titanium, etc., can be used.In addition, aluminum, aluminum alloy, indium oxide, etc. can be used on the surface of the support. The above-mentioned conductive support is formed by vacuum deposition of a film such as a tin oxide alloy, or 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. , plastic having a conductive binder, etc. can be used.

An undercoat layer having barrier and adhesive functions can also be provided between the conductive support 1 and the photosensitive layer. The subbing layer can be formed from casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane, gelatin, aluminum oxide, or the like. The thickness of the undercoat layer is suitably 5 μm or less, preferably 0.5 to 3 μm. In order for the subbing layer to perform its function, its volume resistivity must be 107 Ω・c.
It is desirable that it is more than m.

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, or It can be formed by dispersing and coating with a suitable binder (binder resin) (or without a binder).

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

The solvent used in the paint for the charge generation layer is selected based on the solubility and dispersion stability of the resin and charge transport material used, and organic solvents include alcohols, sulfoxides, ethers, esters, Aliphatic 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 Meyer bar coating method, or a blade coating method.

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

Examples of the binder (binder resin) 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 of the constituent units of these resins, such as styrene-butadiene copolymer, styrene -acrylonitrile copolymer, styrene-maleic acid copolymer, etc. It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

The thickness of the charge transport layer is 5 to 50 μm, preferably 8 to 20 μm, and the weight ratio of the charge transport material to the binder is former/latter = 5/1 to 1/5, preferably 3/5. 1
It is about ~1/3. Coating can be performed by the coating method described above.

Furthermore, since dyes, pigments, organic charge transport substances, etc. are generally sensitive to ultraviolet rays, ozone, stains caused by oil, etc., and contact with metals, etc., a protective layer may be provided on their surfaces, if 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 is made of a suitable organic resin such as polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer, etc. It can be formed by applying a solution dissolved in a 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 41, image exposure means 43, developing means 44, transfer charging means 45, cleaning means 47, and pre-exposure means 48 are arranged on the circumferential surface of an electrophotographic photoreceptor 42.

A voltage (for example, 200
DC voltage between V and 2000V and peak-to-peak voltage 400V
A pulsating current voltage superimposed with an alternating current voltage of 0 V or less is applied to charge the surface of the electrophotographic photoreceptor 42, and the image on the document is exposed onto the photoreceptor by the image exposure means 43 to form an electrostatic latent image. Next, by making the developer in the developing means 44 adhere to the photoreceptor, the electrostatic latent image on the photoreceptor 42 is developed (visualized), and the developer on the photoreceptor 42 is transferred to the charging means 45.
The developer is transferred onto a transfer member 46 such as paper, and the developer remaining on the photoreceptor without being transferred to the paper during transfer is collected by the cleaning means 47.

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 48 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 device, a corona charger 55 for primary charging, an image exposure means 53, a developing means 54, a charging member 51 for transfer charging, a cleaning means 57, and a pre-exposure means 52 are arranged on the circumferential surface of an electrophotographic photoreceptor 52. .

A voltage (for example, a DC voltage of 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 65 for primary charging, an image exposure means 63, a developing means 64, a corona charger 68 for transfer charging, and a cleaning means 67 are arranged on the circumferential surface of an electrophotographic photoreceptor 62.

A voltage (for example, AC peak-to-peak voltage of 500 to 2000 V) is applied to the charging member 61 for charge removal that is placed in contact with the electrophotographic photoreceptor 62 to charge the electrophotographic photoreceptor 12.
It is possible to eliminate the charge on the top.

When using the electrophotographic device equipped with the charging member of the present invention as a facsimile printer,
The optical image exposure L is exposure for printing received data. FIG. 7 is a block diagram showing an example of this case.

In FIG. 7, a controller 71 controls an image reading section 70 and a printer 79. The entire controller 71 is controlled by a CPU 77. The read data from the image reading section 70 is transmitted to the partner station through the transmitting circuit 73. Data received from the other station is sent to the printer 79 through the receiving circuit 72. Image memory 7
6 stores predetermined image data. A printer controller 78 controls a printer 79. 74 is a telephone.

After the image received from the line 75 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 72, the image information is decoded by the CPU 77 and sequentially transferred to the image memory 76. is stored in next,
Once at least one page worth of images is stored in the memory 76,
Record an image of that page. The CPU 77 reads one page of image information from the memory 76 and sends it to the printer controller 7.
One page of image information decoded into 8 is sent. When the printer controller 78 receives one page of image information from the CPU 77, it controls the printer 79 to record the image information of that page. Note that the CPU 77 is the printer 7.
9, image information of the next page is being received.

As described above, image information is received and recorded.

The charging member of the present invention can be applied to an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductor that is susceptible to deterioration in terms of mechanical strength and chemical stability. can be demonstrated significantly.

The method for installing the charging member of the present invention in contact with the photoreceptor is not limited to a particular method. The charging member can be either fixed or movable, such as rotating in the same direction as the photoreceptor or in the opposite direction. Furthermore, it is also possible to cause the charging member to function as a developer cleaning device on the photoreceptor.

Regarding the voltage and application method to be applied to the charging member in the direct charging of the present invention, it depends on the specifications of each electrophotographic apparatus, but in addition to the method of instantaneously applying a desired voltage, the method of applying the voltage to the charging member For protection purposes, the applied voltage can be increased in stages, or if DC and AC are applied in a superimposed manner, 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. When primary charging is applied only with DC voltage, uniform charging cannot be achieved.

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

[0054] When used for static elimination charging, it is necessary to apply only an alternating current voltage.

Further, in the present invention, any method known in the field of electrostatic photography can be employed for processes such as image exposure, development, and cleaning. Further, the developer is not limited to a specific type, such as the type of developer. The charging member of the present invention can be used not only in copiers but also in electrophotographic applications such as laser printers, CRT printers, and electrophotographic plate making systems.

[0056]

[Example] Example 1 An aluminum cylinder (outer diameter 6
0 mm x length 260 mm x wall thickness 0.5 mm) was prepared.

Copolymerized nylon [Product name: CM8000 (
(manufactured by Toray Industries, Inc.)] and 4 parts of Type 8 nylon [trade name: Laccamide 5003 (manufactured by Dainippon Ink Co., Ltd.)] were dissolved in a mixed solvent of 50 parts of methanol and 50 parts of n-butanol, and the mixture was placed on the above support. A 0.6 μm thick undercoat layer was formed by dip coating.

10 parts of a disazo pigment having the following structural formula "Chemical formula 1"

[0059]

[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
The mixture was mixed and dispersed with 20 parts in a sand mill for 10 hours. A coating solution obtained by adding 30 parts of methyl ethyl ketone to the dispersion was coated on the undercoat layer, and a charge generation layer (0.15 parts
(μm thickness) was formed.

Prepare 10 parts of polycarbonate Z resin [weight average molecular weight 120,000 (manufactured by Mitsubishi Gas Chemical Co., Ltd.)], and add a hydrazone compound of the following structural formula "Chemical formula 2".

[0061]

[Case 2] It was dissolved together with 10 parts in 80 parts of monochlorobenzene.

This was coated on the charge generation layer to form a charge transport layer (16 μm thick), and electrophotographic photoreceptor No.
．． 1 was manufactured.

Next, 100 parts by weight of chloroprene rubber was melted and kneaded with 5 parts by weight of conductive carbon, and a stainless steel shaft (diameter 8 mm x length 260 mm) was passed through the center of the obtained mass so that it had an outer diameter of 20 mm x length of 240 mm. Molded into
A conductive elastic layer of a roller-shaped charging member was provided.

The volume resistivity of the conductive elastic layer of this charging member was measured at a temperature of 22° C. and a humidity of 60%, and it was found to be 3×1.
It was 0.04 Ω·cm.

Polyvinyl alcohol (structural formula 1; 10%
10 parts by weight (viscosity of aqueous solution: 50 centipoise) and 90 parts by weight of pure water
A roller-shaped charging member was manufactured by dissolving the mixture in parts by weight and applying it by dip coating on the conductive elastic layer of the charging member to form a polymer layer having a thickness of 200 μm after drying. A polymer layer was similarly provided on an aluminum sheet, and the volume electrical resistivity of the layer was measured.

As shown in FIG. 3, this charging member is installed in a normal development type copying machine [product name: PC-20 (manufactured by Canon Inc.)] in place of the primary corona charger, and the electrophotographic photoreceptor and driven rotation are connected to each other. while the primary charging voltage is -750V DC voltage.
and an AC peak-to-peak voltage of 1500 V are applied in a superimposed manner,
The dark potential and bright potential of the electrophotographic photoreceptor were measured and the formed image was evaluated. The results are shown in Table 2.

Furthermore, the volume electrical resistivity of the polymer layer of the charging member, the potential characteristics and the image when this charging member is installed in a normal development type copying machine under low temperature and low humidity conditions of 15° C. and 10% humidity were determined. Table 2 shows the results of the same evaluation.

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

10 parts by weight of polymethacrylic acid copolymer (Structural formula 5 in Table 1; viscosity of 10% aqueous solution 70 centipoise) was dissolved in 90 parts by weight of pure water, and the resulting coating liquid was applied to the charging member. A roller-shaped charging member was prepared by dip coating on the conductive elastic layer and providing a polymer layer (film thickness after drying: 200 μm). This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

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

9 parts by weight of polyethyleneimine (Structural formula 6; viscosity of 10% aqueous solution 20 centipoise) and 1 part by weight of toluylene diisocyanate are dissolved in 90 parts by weight of n-butanol, and the resulting coating liquid is applied to the above-mentioned charging member. The polymer layer (film thickness after drying is 200 mm) is applied by dip coating on top of the conductive elastic layer.
μm) to create a roller-shaped charging member. This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Example 4 A conductive elastic layer of a charging member was prepared in the same manner as in Example 1.

α-starch (viscosity of 10% aqueous solution: 350
Centipoise) was heated and dissolved in 90 parts by weight of pure water, and the resulting coating solution was dip coated onto the conductive elastic layer of the charging member to form a polymer layer (film thickness after drying of 200 μm). )
was installed to create a roller-shaped charging member. This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

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

Copolymerized nylon (6-66-10-12)
10 parts by weight was dissolved in 90 parts by weight of methanol, and the resulting coating liquid was dip coated on the conductive elastic layer made of the charging member to form a resin layer (film thickness after drying: 200 μm). , a roller-shaped charging member was created. This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

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

8 parts by weight of polyester polyol [trade name: Nipporan 121 (manufactured by Nippon Polyurethane Co., Ltd.)] and 2 parts by weight of tolylene diisocyanate were mixed with 90 parts by weight of n-butanol.
The resulting coating liquid was applied by dip coating onto the conductive elastic layer made of the charging member to form a polymer layer (film thickness after drying of 200 μm), and a roller-shaped charging member Created the parts. This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

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

[0079] 10 parts by weight of silicone RTV rubber was dissolved in 90 parts by weight of toluene, and the resulting coating liquid was dip-coated on the conductive elastic layer of the charging member, and the polymer layer (film after drying) was coated by dip coating. A roller-shaped charging member was prepared by providing a charging member with a thickness of 200 μm. This was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0080]

[Table 2] (1) Comparing Examples 1, 2, 3, and 4 with Comparative Example 1 reveals the following: Image defect called wavy fog caused by hardening of the polymer layer at low temperature and low humidity. The present invention can prevent the occurrence of. (2) Comparing Examples 1, 2, 3, and 4 with Comparative Examples 1, 2, and 3 reveals the following: It is possible to prevent fusion between the charging member and the photoreceptor, and to suppress the occurrence of horizontal streak images. Can be done.

As in Comparative Example 2, the volume electrical resistivity remains high in the polyurethane polymer layer, but by incorporating a water-soluble resin into the polymer layer as in Examples 1, 2, 3, and 4, , an appropriate volume electrical resistivity was obtained and more useful charging characteristics were obtained.

Next, the characteristics as a transfer charger were investigated.

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, and a stainless steel shaft (outer diameter 8 mm x length 260 mm) was passed through the center of the resulting mass to form a cylindrical shape (outer diameter 30 mm x length). 240 mm), and a conductive elastic layer of a roller-shaped charging member was provided.

The volume electrical resistivity of this transfer charging member was measured at a temperature of 22° C. and a humidity of 60%, and it was found to be 4×104.
It was Ωcm.

Polyvinyl alcohol (structural formula 1; 10%
10 parts by weight of aqueous solution viscosity 200 centipoise) and 90 parts by weight of pure water
The resulting coating liquid was applied by dip coating onto the conductive elastic layer of the transfer charging member to form a polymer layer (film thickness after drying of 100 μm), and a roller-shaped transfer charging member was prepared. I created a component for this purpose. A polymer layer was similarly provided on an aluminum sheet, and the volume electrical resistivity of the resin was measured.

[0087] This transfer charging member was used in a normal development type copying machine [
Product name: PC-20 (manufactured by Canon Inc.)] is installed in place of the transfer corona charger, and the transfer charge is DC -50.
0V was applied, and the image formed and the state of the transfer charging member were evaluated. The results are shown in Table 3.

Furthermore, the volume electrical resistivity of the polymer layer of the transfer charging member under low temperature and low humidity conditions of 15° C. and 10% humidity,
Table 3 shows the results of evaluation of the image formed by attaching this transfer charging member to a normal development type copying machine and the state of the transfer charging member.

Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. 10 parts by weight of polyacrylic acid (Structural formula 2; viscosity of 10% aqueous solution 100 centipoise) is dissolved in 90 parts by weight of pure water, and the resulting coating liquid is immersed on the conductive elastic layer of the transfer charging member. Coating, polymer layer (film thickness after drying: 100 mm)
μm) to create a roller-shaped transfer charging member. This was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

Example 7 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. 9 parts by weight of polyethyleneimine (Structural formula 6; viscosity of 10% aqueous solution 80 centipoise) and 1 part by weight of hexamethylene diisocyanate are dissolved in 90 parts by weight of n-butanol, and the resulting coating liquid is applied to the conductive layer of the transfer charging member. The polymer layer (thickness after drying is 10 mm) is applied by dip coating on the elastic layer.
0 μm) to produce a roller-shaped transfer charging member. This was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

Example 8 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. 10 parts by weight of α-starch (viscosity of 10% aqueous solution, 700 centipoise) was dissolved by heating in 90 parts by weight of pure water, and the resulting coating liquid was dip coated onto the conductive elastic layer of the transfer charging member. A roller-shaped transfer charging member was prepared by providing a polymer layer (film thickness after drying: 100 μm). This was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

Comparative Example 4 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Copolymerized nylon (-6-66-10-12) 1
0 parts by weight of methanol is dissolved in 90 parts by weight of methanol, and the resulting coating liquid is dip coated onto the conductive elastic layer of the transfer charging member to form a polymer layer (film thickness after drying: 100 μm). hand,
A roller-shaped transfer charging member was created. This was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

Comparative Example 5 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. Polyester polyol [Product name: Nipporan 1
21 (manufactured by Nippon Polyurethane Co., Ltd.)] and 2 parts by weight of tolylene diisocyanate were dissolved in 90 parts by weight of n-butanol, and the resulting coating liquid was immersed on the conductive elastic layer of the transfer charging member. Coating, polymer layer (film thickness after drying: 1
00 μm) to create a roller-shaped transfer charging member. Table 3 shows the results of evaluating this in the same manner as in Example 5.
Shown below.

Comparative Example 6 A conductive elastic layer of a transfer charging member was prepared in the same manner as in Example 5. 10 parts by weight of silicone RTV rubber was dissolved in 90 parts by weight of toluene, and the resulting coating liquid was dip-coated on the conductive elastic layer of the transfer charging member to form a polymer layer (film thickness after drying of 100 μm). ) to create a roller-shaped transfer charging member. This was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

[0095]

[Table 3] (3) Comparison of Examples 5, 6, 7, and 8 with Comparative Example 4 reveals the following: With the charging member of the present invention, neither density decrease nor wavy fog occurs even under low temperature and low humidity. , high image quality can be maintained. (4) Furthermore, from a comparison of Examples 5, 6, 7, and 8 and Comparative Examples 5 and 6, the following is found: In the present invention, the transfer charging member does not stick to the photoreceptor, and also does not stick to the toner. It is useful not to cause any defects on the photoreceptor or the charging member, and stable image formation can be performed.

Next, the characteristics as a static eliminator were investigated.

Example 9 A photoreceptor was produced in the same manner as in Example 1.

100 parts by weight of chloroprene rubber and 5 parts by weight of conductive carbon were melt-kneaded, and the plate-like material obtained was placed on a stainless steel plate (2 mm x 260 mm) to form the plate shape shown in Fig. 3 (free length 10 mm x 240 mm). A conductive elastic layer made of a blade-shaped charging member was provided. The volume electrical resistivity of this static elimination charging member is determined at a temperature of 22°C.
Measured in an environment with 60% humidity, 4 x 104 Ω・cm
Met.

Polyvinyl alcohol (structural formula 1; 10%
(Viscosity of aqueous solution: 560 centipoise) 10 parts by weight of pure water
0 parts by weight, and the resulting coating liquid was applied by dip coating onto the conductive elastic layer of the static elimination/charging member, a polymer layer (film thickness after drying: 100 μm) was formed, and a blade shape was formed. A static electricity removal charging member was created. A polymer layer was similarly provided on an aluminum sheet, and its volume electrical resistivity was measured.

[0100] This static eliminating charging member is used in a normal development type copying machine [
Product name: PC-20 (manufactured by Canon Inc.)] is installed in place of the pre-exposure static eliminator, and AC peak-to-peak voltage 10 is used for static charge removal.
00V was applied, and the residual potential image after static elimination and the state of the static elimination charging member were evaluated. The results are shown in Table 4.

[0101] Furthermore, the volume electrical resistivity of the polymer layer of the static electricity removal charging member under low temperature and low humidity conditions of 15° C. and 10% humidity,
Table 4 shows the results of evaluation of the image formed by attaching this static eliminating charging member to a normal development type copying machine and the condition of the static neutralizing charging member.

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

Polymethacrylic acid (viscosity of 10% aqueous solution 2
30 centipoise) was dissolved in 90 parts by weight of pure water, and the resulting coating liquid was dip-coated on the conductive elastic layer of the static elimination/charging member. 100μ
m) to create a blade-shaped static elimination/charging member. This was evaluated in the same manner as in Example 9, and the results are shown in Table 4.

Example 11 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared.

[0105] 9 parts by weight of polyethyleneimine (Structural formula 3; viscosity of 10% aqueous solution 70 centipoise) and 1 part by weight of tolylene diisocyanate were dissolved in 90 parts by weight of n-butanol, and the resulting coating liquid was used for the above-mentioned charge eliminating charge. Dip coating is performed on the conductive elastic layer of the member, and the polymer layer (film thickness after drying is 10
0 μm) to create a blade-shaped static elimination/charging member. This was evaluated in the same manner as in Example 9, and the results are shown in Table 4.

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

α-starch (viscosity of 10% aqueous solution: 300
Centipoise) was heated and dissolved in 90 parts by weight of pure water, and the resulting coating solution was dip-coated on the conductive elastic layer of the static elimination/charging member. 100μ
m) to create a blade-shaped static elimination/charging member. This was evaluated in the same manner as in Example 9, and the results are shown in Table 4.

Comparative Example 7 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared.

[0109] The above-mentioned charge eliminating member was used as it was without providing a polymer layer.

[0110] This was evaluated in the same manner as in Example 9, and the results are shown in Table 4.

Comparative Example 8 In the same manner as in Example 9, a conductive elastic layer of a static electricity removal/charging member was prepared.

8 parts by weight of polyester polyol [trade name: Nipporan 121 (manufactured by Nippon Polyurethane Co., Ltd.)] and 2 parts by weight of tolylene diisocyanate were mixed with 90 parts by weight of n-butanol.
parts by weight, and the resulting coating liquid is dip-coated on the conductive elastic layer of the static elimination/charging member to form a polymer layer (film thickness after drying: 100 μm), and a blade-shaped A static electricity removal charging member was created. This was evaluated in the same manner as in Example 9, and the results are shown in Table 4.

Comparative Example 9 Table 4 shows the results of the evaluation in the same manner as in Example 9, in which static electricity was removed during pre-exposure without using the charging member for charge removal of the present invention.

[0114]

[Table 4]

[0115]

Effects of the Invention The contact charging member of the present invention does not cause much change in electrical resistance due to environmental changes and can form stable images. In addition, charge loss is less likely to occur.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a cylindrical charging member of the present invention.

FIG. 2 is a schematic cross-sectional view of a cylindrical modification of the charging member of the present invention.

FIG. 3 is a schematic cross-sectional view of a flat plate form of the charging member of the present invention.

FIG. 4 is a schematic cross-sectional view of one embodiment of an electrophotographic apparatus equipped with a charging member of the present invention.

FIG. 5 is a schematic cross-sectional view of another embodiment of an electrophotographic apparatus equipped with a charging member of the present invention.

FIG. 6 is a schematic cross-sectional view of another embodiment of an electrophotographic apparatus equipped with a charging member of the present invention.

FIG. 7 is a block diagram of a facsimile machine whose constituent unit is a printer equipped with the charging member of the present invention.

[Explanation of symbols]

1 Conductive support, 2 Lower layer, 3 Resin layer, 4 Protective layer, 5 Insoluble resin powder, 41 Charging member, 42 Electrophotographic photoreceptor, 43 Image exposure means, 44 Developing means, 45 Transfer charging means, 47 Cleaning means, 48 Pre-exposure means, 51 Charging member, 52 Electrophotographic photoreceptor, 53 Image exposure means, 54 Developing means, 55 Transfer charging means, 57 Cleaning means, 58 Pre-exposure means, 61 Charging member, 62 Electrophotographic photoreceptor, 63 Image exposure means, 64 Developing means, 65 Transfer charging means, 67 Cleaning means, 68 Pre-exposure means, 70 Image reading unit, 71 Controller, 72 Receiving circuit, 73 Transmission circuit, 74 Telephone, 75 line, 76 Image memory, 77 CPU, 78 Printer controller, 79 Printer.

Claims (8)

[Claims] Claim 1: A charging member having a conductive elastic layer on a conductive support, on the conductive elastic layer, a material selected from polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyethyleneimine, and starch. A charging member comprising a polymer layer containing a water-soluble polymer. 2. The charging member according to claim 1, for charging an electrophotographic organic photoreceptor by contact with the photoreceptor. 3. The charging member according to claim 1, wherein the charging member is primarily charged by applying a DC voltage and an AC voltage in a superimposed manner. 4. The charging member according to claim 1, for transferring the developer from the electrophotographic photoreceptor to the transfer target member by applying a DC voltage and an AC voltage in a superimposed manner. 5. The charging member according to claim 1, for eliminating static electricity by applying an alternating current voltage. 6. The charging member according to claim 1 and a member to be charged that is charged by contacting the contact charging member are integrally supported together with at least an electrophotographic photoreceptor to form a unit, and the unit is detachably attached to an apparatus main body. An electrophotographic device unit characterized in that it is a single unit that can be used. 7. An electrophotographic apparatus comprising an electrophotographic photoreceptor, a latent image forming means, a means for developing the formed latent image, and a means for transferring the developed image to a transfer material, wherein the charging member is the electrophotographic device according to claim 1. An electrophotographic device characterized by being as described in . 8. A facsimile machine comprising an electrophotographic apparatus equipped with the charging member according to claim 1 and a receiving means for receiving image information from a remote terminal.