JP2001290340A - Contact electrifying device, method for contact electrifying and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact electrifying device with which a good image can be obtained by using an electrifying body which can be uniformly electrified without nonuniformity and has excellent cleaning properties, and to provide a method for contact electrification by using the device and an electrophotographic device equipped with the device. SOLUTION: In the contact electrifying device to electrify a body to be electrified by externally applying voltage to an electrifying member disposed in contact with the objective body, the contact electrifying member has a resistance layer and a surface layer having >=1.4 μm and <=2.4 μm surface roughness Rp (average line height) and <=1.45 μm Rv (average line depth) and containing a conducting agent in N-alkoxymethyl nylon. The contact electrifying device, the method for contact electrification and the electrophotographic device are characterized in that the voltage externally applied is a pulsating voltage generated by superposing a DC voltage and an AC voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact charging device for directly charging a member to be charged by contacting a charging member, a contact charging method, and an electrophotographic apparatus having the contact charging device.

[0002]

2. Description of the Related Art Heretofore, inorganic photoconductive materials such as selenium, cadmium sulfide and zinc oxide have been known as photoconductive materials used in electrophotographic photosensitive members. These photoconductive materials have a number of advantages, for example, they can be charged to an appropriate potential in a dark place, have little charge dissipation in a dark place, or can quickly dissipate charges by light irradiation. It has various disadvantages.

For example, in a selenium-based electrophotographic photosensitive member,
Crystallization proceeds easily due to factors such as temperature, humidity, dust, and pressure. Particularly, when the ambient temperature exceeds 40 ° C., crystallization is remarkable, and there is a disadvantage that chargeability is reduced and white spots are generated on an image.

Cadmium sulfide-based electrophotographic photoreceptors do not provide stable sensitivity in a humid environment, and sensitizing effects of sensitizing dyes represented by rose bengal in zinc oxide-based electrophotographic photoreceptors. However, such a sensitizing dye has a drawback that a stable image cannot be provided for a long period of time because charge deterioration due to charging and light fading due to exposure light occur.

On the other hand, it has been discovered that certain organic compounds exhibit photoconductivity. For example, organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene, carbazole, anthracene, pyrazolines,
In addition to low molecular weight organic photoconductors such as oxadiazoles, hydrazones and polyarylalkanes, phthalocyanine pigments, azo pigments, cyanine dyes, polycyclic quinone pigments, perylene pigments, indigo dyes, thioindigo dyes or squarices Organic pigments and dyes such as acid methyl dyes are known. In particular, organic photoconductors such as organic pigments and dyes having photoconductivity are easier to synthesize than inorganic materials, and the variety in which compounds exhibiting photoconductivity in an appropriate wavelength range can be selected has been expanded. Has many suggestions.

For example, US Pat. No. 4,123,270, US Pat. No. 4,251,613, US Pat.
No. 251614, U.S. Pat. No. 4,256,821, U.S. Pat. No. 4,260,672, U.S. Pat. No. 4,268,596, U.S. Pat. No. 4,278,747, and U.S. Pat. No. 4,293,628. As described above, an electrophotographic photoreceptor using a disazo pigment having photoconductivity as a charge generating material in a photosensitive layer which is functionally separated into a charge generating layer and a charge transporting layer is known.

In a charging process in an electrophotographic process using such an electrophotographic photosensitive member, a high voltage (DC 5 to 8 KV) is applied to a metal wire and charging is performed by a corona generated. However, or allowed to proceed image blurring or deterioration denature the surface of the electrophotographic photosensitive member by corona products such as ozone and NO _X during corona generating in this way, contamination of the wire affects the image quality,
There were problems such as white spots and black stripes on the image. In particular,
The electrophotographic photoreceptor in which the photosensitive layer contains an organic photoconductor has chemical reactivity because the organic photoconductor is an organic compound, and is easily deteriorated by corona products.

On the other hand, the electric current flowing toward the electrophotographic photosensitive member is only 5 to 30% of the electric power, and most of the electric current flows to the shield plate and is inefficient as a charging means.

In order to compensate for such a disadvantage, Japanese Patent Application Laid-Open No.
178267, JP-A-56-104351, JP-A-58-40566, and JP-A-58-13
Japanese Patent Application Laid-Open No. 9156 and JP-A-58-150975 disclose a method in which a charging member is brought into contact with a member to be charged such as an electrophotographic photosensitive member to directly charge the member.

Conventionally, as a charging member used for direct charging, a conductive rubber roller in which conductive particles such as carbon are dispersed in a metal core material, or nylon or the like disclosed in Japanese Patent Publication No. 50-13661 is used. Rollers coated with polyurethane are known.

[0011]

However, the discharge characteristics and cleaning properties vary greatly depending on the surface roughness of the surface layer, and the discharge characteristics and cleaning properties are not defined in the commonly used specifications of surface roughness such as Ra and Rz. There was a problem that it was difficult to balance gender.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a contact charging device capable of uniformly charging without uneven charging and having excellent cleaning properties and obtaining a good image, a contact charging method using the same, and a contact charging method using the same. To provide an electrophotographic apparatus having the same.

It is a further object of the present invention to provide a contact charging device capable of charging at a relatively low voltage, a contact charging method using the same, and an electrophotographic apparatus having the same.

[0014]

According to the present invention, there is provided a contact charging device for applying an external voltage to a charging member arranged in contact with a member to be charged to charge the member to be charged. Contact charging having a surface layer having a surface roughness Rp (average line height) of not less than 1.4 μm and not more than 2.4 μm and an Rv (average line depth) of not more than 1.45 μm and a resistance layer. A contact charging device, wherein the externally applied voltage is a pulsating voltage obtained by superimposing a DC voltage and an AC voltage.

According to the present invention, the contact charging member has a surface roughness Rp (average line height) of at least 1.4 μm and at least 2.4 μm.
m, and a contact charging member having a surface layer and a resistance layer having an Rv (average line depth) of 1.45 μm or less, and by applying a pulsating voltage of a DC voltage and an AC voltage from outside. And a charging method for charging a member to be charged in contact with the charging member.

Further, according to the present invention, on the peripheral surface of the electrophotographic photosensitive member, a primary charging member disposed in contact with the electrophotographic photosensitive member, an exposing unit, a developing unit, a transfer charging unit, a cleaning unit, Wherein the contact charging member has a surface roughness Rp (average line height) of 1.4 μm in an electrophotographic apparatus for charging the electrophotographic photosensitive member by applying an external voltage to the primary charging member. Not less than 2.4 μm and Rv
(Average line depth) is a contact charging member having a surface layer and a resistance layer of 1.45 μm or less, and a voltage applied from outside is a pulsating voltage obtained by superimposing a DC voltage and an AC voltage. Is provided.

[0017]

Embodiments of the present invention will be described below in detail.

N for forming the surface layer of the charging member of the present invention
-Alkoxymethylated nylon is obtained by substituting the hydrogen atom of an amide bond -NHCO- of nylon with an alkoxymethyl group such as a methoxymethyl group, an ethoxyethyl group and a propoxymethyl group. It is soluble, and has particularly high solubility in lower alcohols. In the case of alcohol solubility, alcohol can be used as the solvent, so that the surface layer can be formed without dissolving the lower layer such as rubber.

As an example of the synthesis of N-alkoxymethylated nylon, for example, 50 g of nylon-6 resin is mixed with formic acid 2
The mixture is stirred and dissolved in a mixed solvent of 50 g / 250 g of acetic anhydride. 15 g of paraformaldehyde and 15 g of methanol are added thereto, and the mixture is heated to 60 ° C. and reacted for 5 hours. Next, the reaction solution is cooled to room temperature, poured into 5 liters of acetone, and reprecipitated and filtered to obtain a white reaction product. This product is washed by stirring in a large amount of water and filtered.
Drying under reduced pressure under the condition of ２０20 mmHg gives 54.1 g of N-methoxymethylated nylon 6 (methoxymethyl group substitution rate: 30.6%).

The surface layer of the charging member in the present invention may be made of another resin such as nylon 6, nylon 66, nylon 610, nylon 11 and nylon 12 as long as the functions such as resistance, environmental stability and hardness are not impaired. Polyamide resins such as those obtained by copolymerization of nylon and the like can be contained, and alcohol-soluble copolymerized nylon such as nylon 6/66 / bis (4-aminocyclohexyl) methane 6 copolymer is particularly preferable.

The N-alkoxymethylated nylon forming the surface layer of the charging member can maintain a constant moisture absorption even when the environment changes, so that the N-alkoxymethylated nylon has excellent environmental stability, especially low temperature and low humidity. Below (for example, 15 ° C./10% RH)
Therefore, since the volume resistance hardly changes, the charging ability is always stable, and uniform charging without uneven charging can be performed.

Furthermore, the surface layer formed of N-alkoxymethylated nylon has a volume resistivity of 10 ⁶ to 10 ¹² Ω · c as well as a stability of the volume resistance against environmental changes.
m, especially 10 ⁸ to 10 ¹¹ Ω · cm.

Further, the resistance can be further reduced by adding a metal oxide or carbon, and the volume resistivity can be reduced to 10 ^3.
It can be set to 〜１０10 ⁶ Ω · cm. Further, the volume resistivity of the resistance layer needs to be set slightly higher than the surface layer in consideration of the insulating property, but by adjusting the volume resistivity to 10 ⁸ Ω · cm to 10 ¹¹ Ω · cm, the insulating property and the lowering of the voltage can be secured. . The low resistance of the surface layer and the resistance layer is particularly effective against dielectric breakdown of the member to be charged and image defects accompanying the breakdown.

That is, in the case of direct charging, if a high voltage is applied to a charging member which is arranged in contact with a member to be charged, a defective portion inside the member to be charged will cause discharge breakdown. Such an object to be charged becomes non-uniformly charged, and furthermore, an excessive current flows from the charging member to the destruction point, and the voltage applied to the charging member drops. As a result, when the member to be charged is an electrophotographic photosensitive member, charging failure occurs over the entire contact area of the electrophotographic photosensitive member, and appears on an image as a white band in the regular image system and a black band in the reversal developing system. . In order to prevent these, it is preferable to reduce the voltage applied to the charging member to a low voltage, and to perform uniform charging by applying the low voltage, the surface layer and the resistance layer of the charging member are It is preferable to keep the resistance low.

Further, products such as ozone and NO _X during the charging and applying a high voltage will be generated many electrophotographic photosensitive member having a photosensitive layer containing an electrophotographic photosensitive member, particularly an organic photoconductor In this case, an adverse effect such as blurring of an image, image deletion, or the like is exerted.

On the other hand, as in the present invention, the surface layer of the charging member is made of N-alkoxymethylated nylon to have a volume resistivity of 10 ³ Ω · cm to 10 ⁶ Ω · cm, and the volume resistivity of the resistance layer is 10 Ω · cm. would be ^{8 ~10 11 Ω} · cm, it is possible to uniform charging at low voltage, in which image defects are significantly improved.

From the above, as the voltage applied to the charging member of the present invention, a low voltage DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage can be applied. A pulsating voltage in which a DC voltage of 200 V to ± 2000 V and an AC voltage of 4000 V or less between peaks are superimposed is preferable.

Further, a resin or rubber such as hydrin rubber, urethane, silicone rubber or EPDM is used for the resistance layer. The charging member having the resistance layer using these materials is a plasticizer for the surface of the electrophotographic photosensitive member. It is necessary to provide a surface layer in order to solve problems such as seepage and fusion of the surface, and it is necessary to maintain the surface layer at a low resistance as described above. ,
There is a problem that the member to be charged is easily shaved.

Further, the discharge characteristics to the member to be charged vary depending on the surface condition of the surface layer. Even when the same voltage is applied, the amount of current supplied to the discharge is different. The amount of current increases, and if the current is smooth, it is difficult to discharge, and the amount of discharge current decreases. The amount of discharge current needs to flow more than a certain amount to eliminate image defects such as sand fog.
If the amount is too large, scraping of the member to be charged is promoted and the life is shortened, so that optimization is required.

The appropriate value of the discharge current is 50 to 80 μA. If the discharge current is less than 50 μA, the amount of the current is insufficient, and a kind of image defect such as defective charging such as sand fog occurs. In addition, 80μ
If it exceeds A, the abrasion of the member to be charged is promoted, and the life is shortened. The surface roughness Rp (average line height) of the charged body for obtaining 50 μA of the lower limit of the appropriate value of the discharge current is 1.4 μm,
The surface roughness Rp (average line height) for obtaining an appropriate upper limit of 80 μA was 2.4 μm.

Further, the cleaning property of the charged body is such that when the surface is rough, foreign substances such as toner external additives and paper powder easily accumulate in the concave sections, and it is difficult to clean the foreign substances. Foreign matter hardly accumulates
It was found that a surface roughness contradictory to the discharge characteristics, such as good cleaning properties, was required. There is a correlation between the number of sheets having image defects due to defective cleaning of the charged body and the surface roughness Rv (average line depth). When the number of sheets is 45,000 or more, the surface roughness Rv (average line depth) is obtained. Had to be 1.45 μm or less. The surface roughness Rv (average line depth) is the depth of the concave portion. If the surface roughness Rv exceeds 1.45 μm, external additives of toner and fine paper powder attached to the charged member cannot be cleaned, and the uniformity of charging becomes poor. It is considered that the image disappeared and became an image defect.

Therefore, an evaluation was made using the average line height Rp and the average line depth Rv instead of the conventional surface roughness Rz, to find a point at which both characteristics (discharge characteristics and cleaning properties) are compatible.

Hereinafter, the configuration of the present invention will be described.

The charging member of the present invention has a multilayer structure on the conductive support 2 as shown in FIG. 1, and may have any shape such as a roller and a blade.

A metal core such as iron, copper and stainless steel is used as the conductive support 2 and a metal such as aluminum and copper, a conductive polymer such as polyacetylene, polypyrrole and polythiophene, or carbon is dispersed as the base layer 3. The conductive layer is formed by dip coating or spray coating with rubber or insulating resin, and the above-described resistance layer 4 and surface layer 5 are formed on the base layer 3. Incidentally, ⁰ less is 10 preferable than the volume resistivity of the base layer 3 is resistive layer 4 to 1
0 ¹¹ Ω · cm, and particularly preferably 10 ² to 10 ¹⁰ Ω · cm. The thickness of the resistance layer 4 is preferably 50 to 300 μm, and particularly preferably 150 to 250 μm. The thickness of the surface layer 5 is preferably 3 to 50 μm, and particularly preferably 5 to 15 μm.

The alkoxymethylation rate (substitution ratio of the alkoxymethyl group to all amide bonds of nylon) in the surface layer 5 is determined by the solubility in a solvent, flexibility, adhesion to the resistive layer 4, film formability and resistance. 18% in terms of controllability
The above is preferred.

The measurement of the alkoxymethylation rate is carried out, for example, by the following method using the Vieock-Schwappach method {Berichteder Deutschen Ch.
emischen Gesellschaft, 63,
2318 (1930)}.

[0038]

Embedded image

As shown in the above formula, when heated together with hydroiodic acid, the alkoxy group is easily decomposed to form an alkyl iodide. The generated alkyl iodide is absorbed by a mixed solution of sodium acetate and acetic acid containing a small amount of bromine to become ethyl bromide and iodine bromide. The latter is further oxidized to iodic acid and hydrogen bromide, but excess bromine is decomposed with formic acid, hydrogen bromide is neutralized with sodium acetate, potassium iodide is added, and the liberated iodine is dissolved in sodium thiosulfate solution. Titrate with.

The alkoxymethylation rate is measured as described above.

Next, the surface of the surface layer can be formed to a desired surface without any adverse effect by controlling the concentration of a solvent atmosphere at the time of coating the surface layer, controlling the temperature, performing physical texture treatment, and dispersing fine particles having an appropriate particle size into the surface layer. The method is not limited as long as the surface state (Rp, Rv) can be obtained.

The member to be charged used in the present invention is a dielectric,
There are various types of electrophotographic photoreceptors and the like, and in the case of electrophotographic photoreceptors, they are configured as follows.

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

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

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

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

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

The thickness of the charge generating layer is preferably from 0.01 to 15 μm, particularly preferably from 0.05 to 5 μm, and the mass ratio of the charge generating layer to the binder is from 10: 1 to 1:20.

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

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

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

Examples of the binder used for the charge transport layer include phenoxy resin, polyacrylamide, polyvinyl butyral, polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, Epoxy resins, polyesters, alkyd resins, polycarbonates, polyurethanes or copolymers containing two or more of the repeating units of these resins, such as styrene-butadiene copolymers, styrene-acrylonitrile copolymers and styrene-maleic acid copolymers Can be. Further, it can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 8 to 20 μm, and the mass ratio of the charge transport material to the binder is preferably 5: 1 to 1: 5, particularly preferably 3: 1 to 1 About 1: 3 is preferable. The coating can be performed by the coating method as described above.

Further, since the coloring matter, the pigment, the organic charge transporting material and the like are generally susceptible to stains by ultraviolet rays, ozone and oil, metals and the like, a protective layer may be provided as necessary. In order to form an electrostatic latent image on this protective layer, the surface resistivity is preferably 10 ¹¹ Ω · cm or more.

The protective layer which can be used in the present invention includes polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer and styrene-acrylonitrile. A solution in which a resin such as a copolymer is dissolved by an appropriate organic solvent is applied on the photosensitive layer,
It can be formed by drying. At this time, the thickness of the protective layer is generally in the range of 0.05 to 20 μm. The protective layer may contain an ultraviolet absorber or the like.

The charging member used in the present invention can be applied to an electrophotographic apparatus as shown in FIG. In this apparatus, a primary charging roller 1 serving as a charging member, an exposure unit 6, a developing unit 7, a transfer charging unit 9, a cleaning unit 10, and a pre-exposure unit 11 are arranged on a peripheral surface of an electrophotographic photosensitive member 12.

An external voltage (for example, ± 200) is applied to the primary charging roller 1 which is arranged in contact with the electrophotographic photosensitive member.
DC voltage not less than V and ± 2000 V and peak-to-peak voltage of 40
A pulsating voltage superimposed with an AC voltage of 00 V or less is applied to charge the surface of the electrophotographic photosensitive member 12, and the image on the original is exposed to the electrophotographic photosensitive member by the exposure means 6 to form an electrostatic latent image. Form. Next, the electrostatic latent image on the electrophotographic photosensitive member is developed (visualized) by adhering the developer in the developing means 6 to the electrophotographic photosensitive member, and the developer on the electrophotographic photosensitive member is further developed. Is transferred to the transfer member 8 such as paper by the transfer charging means 9.
The developer remaining on the electrophotographic photosensitive member without being transferred to the transfer-receiving member 8 at the time of transfer by the cleaning unit 10 is collected.

Although an image can be formed by such an electrophotographic process, if residual charge remains on the electrophotographic photosensitive member, the pre-exposure means 11 applies it to the electrophotographic photosensitive member before performing primary charging. It is better to irradiate light to remove residual charges.

The charging member used in the present invention is easily degraded in terms of mechanical strength and chemical stability, and is applied to an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductor. Characteristics can be remarkably exhibited.

The installation of the charging member to be brought into contact with the electrophotographic photosensitive member in the present invention is not limited to a specific method.
As the charging member, any of a fixed system and a moving system such as rotation in the same or opposite direction to the electrophotographic photosensitive member can be used. Further, it is also possible for the charging member to function as a developer cleaning device on the electrophotographic photosensitive member.

The voltage and method of application to the charging member in the direct charging of the present invention depend on the specifications of each electrophotographic apparatus. A method of gradually increasing the applied voltage for the purpose of protecting the body, or a method of applying the voltage in the order of DC → AC or AC → DC if the AC is applied in the form of AC superimposed on DC Can be.

In the electrophotographic apparatus of the present invention,
Processes such as image exposure, development and cleaning Any method known in the field of electrostatography can be adopted, and the type of developer is not limited to a specific one. The electrophotographic apparatus of the present invention can be used not only for copying machines but also for electrophotographic applications such as laser printers, CRT printers, and electrophotographic plate making systems.

[0063]

The present invention will be described in more detail with reference to the following examples. In addition, "part" in an Example shows a mass part.

Example 1 100 parts of chloroprene rubber was melt-kneaded with 5 parts of conductive carbon, and was molded through a stainless steel shaft so as to have a diameter of 20 × 300 mm to provide a base layer of a primary charging roller. The volume resistance of the primary charging roller base layer measured under an environment of a temperature of 22 ° C. and a humidity of 60% was 3 × 10 ⁹ Ω · cm.

Next, the hydrin rubber 100 obtained by copolymerizing epichlorohydrin and ethylene oxide was used.
Then, 0.5 part of conductive carbon was melt-kneaded in each part, and dip coating was performed on the base layer so that the film thickness became 200 μm, thereby providing a primary charging roller resistance layer. Similarly, a resistance layer was provided on the aluminum sheet. At this time, the volume resistance of the resistance layer is 1.5 × 1.
It was 0 ¹⁰ Ω · cm.

Next, N-alkoxymethylated nylon-
6 (alkoxymethylation ratio 30%) 100 parts of conductive carbon 5 parts were kneaded and dissolved in 90 parts of methanol, and dip-coated on the primary charging roller resistance layer to a thickness of 10 μm. A primary charging roller surface layer was provided. A surface layer was similarly provided on the aluminum sheet. At this time, the volume resistance of the surface layer was 1.0 × 10 ⁴ Ω · cm. At this time, the surface roughness Rp of the surface layer was 1.4 μm.
m and Rv were adjusted by performing texture processing so as to be 0.6 μm.

(Example 2) The surface roughness Rp was 2.1 μm,
A primary charging roller was produced in the same manner as in Example 1 except that dip coating was performed so that Rv became 1.2 μm.

(Example 3) The surface roughness Rp was 2.4 μm,
A primary charging roller was produced in the same manner as in Example 1 except that dip coating was performed so that Rv became 0.4 μm.

(Comparative Example 1) The surface roughness Rp was 0.5 μm,
A primary charging roller was produced in the same manner as in Example 1, except that dip coating was performed so that Rv became 1.6 μm.

(Comparative Example 2) Surface roughness Rp is 1.05 μm
A primary charging roller was produced in the same manner as in Example 1, except that dip coating was performed so that m and Rv became 2.0 μm.

(Comparative Example 3) Surface roughness Rp is 2.95 μm
A primary charging roller was produced in the same manner as in Example 1, except that dip coating was performed so that m and Rv became 0.9 μm.

This primary charging roller is mounted in place of a primary charger of a reversal developing type primary charger, exposure light, a developing device, a transfer charger, and a copying machine (GP215: manufactured by Canon) having a cleaning device. , DC voltage -75
A pulsating voltage in which 0 V and an AC peak-to-peak voltage of 1500 V were superimposed was applied, and a durability test was performed to evaluate a discharge current amount, a cleaning property, a shaving amount, and an image evaluation. Table 1 shows the results.

Discharge current amount: At a low voltage, the applied voltage and the current amount change along E = I · R, but when the pressure becomes high, the discharge is accompanied, so that the current value increases from E = I · R. The increase of the current at this time is defined as the discharge current amount.

Cleaning performance: The number of durable sheets at the time when an image becomes defective due to contamination of the primary charger.

Rp (average line height): When a cross-sectional curve obtained by measuring the surface roughness is cut along the average line, the actual state of the cross-sectional curve connecting two points adjacent to each other at the intersection is obtained. Is the distance from the average line of the protruding part.

Rv (average line depth): When a cross-sectional curve obtained by measuring the surface roughness is cut along the average line, the actual state of the cross-sectional curve connecting two points adjacent to each other at the intersection is obtained. The distance from the average line of the recessed part.

Abrasion amount: Abrasion amount of an electrophotographic photosensitive member as a member to be charged when a durability test was performed on 45,000 sheets.

[0078]

[Table 1]

In Comparative Examples 1 and 2, the average line height Rp was 1.
Since it is less than 4, an image defect due to fog occurs in the output image with a small discharge current amount, and the average line depth Rv is 1.
Since it exceeds 45, the surface of the charged body is rough, so that dust easily accumulates, and image defects due to dirt also occur. In Comparative Example 3, since the average line height Rp was more than 2.4 and the discharge current amount was large, the electrophotographic photosensitive member as the member to be charged was scraped.

[0080]

As described above, in a contact charging device for applying a voltage from outside to a charging member placed in contact with a member to be charged and charging the member to be charged, the contact charging member is made of N-alkoxymethyl. Surface roughness Rp (average line height) containing a conductive agent in reinforced nylon is 1.4 μm or more and 2.4 μm
A contact charging member having a surface layer and a resistance layer having an Rv (average line depth) of 1.45 μm or less, and a voltage applied from the outside is a pulsating voltage obtained by superimposing a DC voltage and an AC voltage. With the use of the contact charging device, uniform charging can be performed without charging unevenness, and a good image can be obtained with a charged body excellent in cleaning performance with less shaving of the charged body. .

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a sectional view of a charging member used in the present invention.

FIG. 2 is a diagram showing an example of a schematic view of an electrophotographic apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 charging member (primary charging roller) 2 conductive support 3 base layer 4 resistive layer 5 surface layer 6 exposing means 7 developing means 8 transferred member 9 transfer charging means 10 cleaning means 11 pre-exposure means 12 electrophotographic photosensitive member

Claims (9)

[Claims] 1. A contact charging device for externally applying a voltage to a charging member placed in contact with a member to be charged to charge the member to be charged, comprising: a N-alkoxymethylated nylon containing a conductive agent; The roughness Rp (average line height) is 1.4 μm
Not less than 2.4 μm and Rv (average line depth) of 1.
A contact charging device comprising: a contact charging member having a surface layer of 45 μm or less and a resistance layer, wherein the voltage applied from the outside is a pulsating voltage obtained by superimposing a DC voltage and an AC voltage. 2. The contact charging device according to claim 1, wherein the member to be charged is an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductor on a conductive support. 3. An externally applied voltage of ± 200 V to ± 200 V
The contact charging device according to claim 1, wherein the contact charging device is a pulsating voltage obtained by superimposing a DC voltage of 2000V and an AC voltage of 4000V or less between peak voltages. 4. An N-alkoxymethylated nylon containing a conductive agent and having a surface roughness Rp (average line height) of 1.4 μm.
Not less than 2.4 μm and Rv (average line depth) of 1.
By applying a DC voltage and a pulsating voltage of an AC voltage from the outside to a contact charging member having a surface layer and a resistance layer of 45 μm or less, charging is performed on a member to be charged which is placed in contact with the charging member. A contact charging method, comprising: 5. The contact charging method according to claim 4, wherein the member to be charged is an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductor on a conductive support. 6. An externally applied voltage of ± 200 V to ± 200 V
The contact charging method according to claim 4, wherein the contact charging method is a pulsating voltage in which a DC voltage of 2000V and an AC voltage of 4000V or less are superimposed. 7. A primary charging member disposed on the peripheral surface of the electrophotographic photosensitive member in contact with the electrophotographic photosensitive member, an exposure unit,
An electrophotographic apparatus, comprising a developing unit, a transfer charging unit, and a cleaning unit, for applying an external voltage to the primary charging member to charge the electrophotographic photosensitive member, wherein the charging member is an N-alkoxy. The methylated nylon contains a conductive agent, and has a surface roughness Rp (average line height) of 1.4 μm or more.
4 μm or less and Rv (average line depth) of 1.45 μm
An electrophotographic apparatus having the following surface layer and resistive layer, and wherein a voltage applied from the outside is a pulsating voltage obtained by superimposing a DC voltage and an AC voltage. 8. The electrophotographic apparatus according to claim 7, wherein the electrophotographic photosensitive member has a photosensitive layer containing an organic photoconductor on a conductive support. 9. An externally applied voltage of ± 200 V to ± 200 V
The electrophotographic apparatus according to claim 7, wherein the electrophotographic apparatus is a pulsating voltage obtained by superimposing a DC voltage of 2000 V and an AC voltage having a peak-to-peak voltage of 4000 V or less.