JP2002108063A - Electrifying member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrifying member having both of excellent electrification performance and leak resistance. SOLUTION: This electrifying device 11 has a layered structure to have at least an electrically conductive elastic body layer and a surface layer, which is formed by dispersing an electrically conductive material, layered successively on a core material. The electrically conductive elastic body layer has 1×107 Ωcm or lower volume resistivity and the surface layer has the volume resistivity of 10 to 1×106 times of that of the electrically conductive elastic body layer. The device 11 has 1×105 to 1×1010 Ωcm volume resistivity as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charging member used in an electrophotographic apparatus such as a copying machine, a laser printer, a facsimile, and a composite OA machine.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic system forms a uniform charge on an image carrier (photoreceptor), and forms an electrostatic latent image by a laser or the like that modulates an image signal. The electrostatic latent image is developed with the charged toner to form a toner image. Then, the desired transfer image can be obtained by electrostatically transferring the toner image to the recording medium via an intermediate transfer member or directly.

As described above, in an image forming apparatus using an electrophotographic system, a charging process for forming a uniform charge on an image carrier is performed. As one of charging members for performing such a charging process, there is a contact type charging system. Such a charging member of the contact-type charging system has an advantage that the amount of ozone generated is very small as compared with a corotron or scorotron which is a charging member of a non-contact charging system in general, in which a small current is applied.

[0004] A contact-type charging member is formed by forming a conductive elastic layer on a core material. The charging member is brought into contact with a photosensitive member in an electrophotographic apparatus, and is provided between the charging member and the photosensitive member. By applying a predetermined voltage, a charging potential is applied to the photoconductor.

[0005] The charging member is used for the purpose of blocking bleeding from the conductive elastic layer, adjusting resistance, improving abrasion resistance, reducing toner contamination, preventing pinhole leaks, etc., or resisting environmental pollution. Therefore, in some cases, a structure having two or more layers formed with a surface layer and an intermediate layer in addition to the conductive elastic layer may be employed. However, in a charging member having a configuration of two or more layers,
In particular, it is difficult to achieve both charging performance and leak resistance. That is, the charging performance is improved by lowering the volume resistivity of the entire charging member, but if the volume resistivity is too low, a problem of leakage at the time of charging occurs, and in the charging member having a configuration of two or more layers, It is difficult to balance the charging performance and the leak resistance because the volume resistivity of the entire charging member is governed by the volume resistivity of each layer.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, an object of the present invention is to provide a charging member that achieves both good charging performance and leak resistance.

[0007]

The above object is achieved by the following means. That is, the present invention provides: <1> a charging member having a layer structure in which at least a conductive elastic layer and a surface layer in which a conductive substance is dispersed are sequentially laminated on a core material; The volume resistivity of the elastic layer is 1 × 10 ⁷ Ωcm or less, the volume resistivity of the surface layer is 10 to 1 × 10 ⁶ times the volume resistivity of the conductive elastic layer, and the entire layer structure of the charging member is Has a volume resistivity of 1 × 10 ⁵
帯 電 1 × 10 ¹⁰ Ωcm.

<2> The charging member according to <1>, wherein the conductive substance contained in the surface layer is carbon black having a pH of 6.0 or less. <3> The charging member according to <1> or <2>, wherein the surface layer further contains a fluorine-based polymer compound and / or a silicone-based polymer compound.

<4> The thickness of the surface layer is 1 to 50 μm.
m. The charging member according to any one of <1> to <3>, wherein the charging member has a range of m. <5> The charging member according to any one of <1> to <4>, wherein the conductive elastic layer mainly includes epichlorohydrin rubber.

<6> The charging member according to <5>, wherein the conductive rubber layer further contains 1 to 5% by weight of a second rubber component. <7> The charging member according to <6>, wherein the second rubber component is a nitrile butadiene rubber.

<8> The conductive elastic layer further contains a conductive substance. <1> to <7>
The charging member according to any one of the above. <9> The conductive substance contained in the conductive elastic body layer,
<8> The charging member according to <8>, wherein the charging member is an organic ion conductive substance. <10> The charging member according to <9>, wherein the conductive substance contained in the conductive elastic layer is a quaternary ammonium salt having a benzene ring.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The charging member of the present invention is a charging member having a layer structure in which at least a conductive elastic layer and a surface layer in which a conductive substance is dispersed are sequentially laminated on a core material. And the volume resistivity of the conductive elastic layer is 1 × 10 ⁷ Ωc
m or less, the volume resistivity of the surface layer is 10 to 1 × 10 ⁶ times the volume resistivity of the conductive elastic layer, and the volume resistivity of the entire layer structure of the charging member is 1 × 10 ⁵ to 1 ×. 10 ¹⁰ Ωcm
It is a feature.

The layer structure of the charging member of the present invention includes a conductive elastic material layer and a surface layer, an intermediate layer provided between the conductive elastic material layer and the surface layer, and a core material and a conductive elastic material. Other layers, such as an adhesive layer provided between the body layers, may be provided. Hereinafter, the charging member of the present invention will be described first with respect to the volume resistivity defined in the present invention, and then
A description will be given for each configuration.

<Volume Resistivity> In the present invention, it is essential that the volume resistivity of the conductive elastic layer be 1 × 10 ⁷ Ωcm or less, and 1 × 10 ³ to 1 × 10 ⁷ Ωcm. It is desirable. The volume resistivity of the conductive elastic layer is 1
When it exceeds × 10 ⁷ Ωcm, it becomes difficult to adjust the entire layer structure of the charging member to a volume resistivity suitable for charging performance, and a voltage required to flow a desired current becomes high, so that it is usually used. Since the power supply capacity exceeds 2.7 kV, charging failure may occur.

In the present invention, the volume resistivity of the surface layer is 10 to 1 × 10 ⁶ of the volume resistivity of the conductive elastic layer.
It is essential that it be twice, and it is more preferable that it be 1 × 10 ² to 1 × 10 ⁵ . It is the ratio between the volume resistivity of the surface layer and the volume resistivity of the conductive elastic layer that can achieve a good balance between the charging performance and the leak resistance.
The volume resistivity of the surface layer is 1 of the volume resistivity of the conductive elastic layer.
If it is less than 0 times, black streaks will occur due to leakage, and 1 ×
If more than 10 ^six times, image quality head and ghost occurs.

Here, the surface layer refers to a layer located on the outermost surface of the charging member, and even if an intermediate layer or the like is provided between the layer located on the outermost surface and the conductive elastic layer. Regardless of the intermediate layer or the like, the volume resistivity of the surface layer is defined by the relationship with the volume resistivity of the conductive elastic layer.

The volume resistivity of the conductive elastic layer and the surface layer is as follows:
A sheet-shaped measurement sample made of the same material as the conductive elastic layer or surface layer to be measured is separately prepared, or a portion of the conductive elastic layer or surface layer is cut out from the completed charging member to form a sheet. To prepare a measurement sample, and set the obtained measurement sample on a circular electrode of a volume resistivity measuring device (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.), and measure according to JIS K6991. Can be.

In the present invention, it is essential that the volume resistivity of the entire layer structure of the charging member is 1 × 10 ⁵ to 1 × 10 ¹⁰ Ωcm, and 1 × 10 ⁶ to 1 × 10 ⁹ Ωcm. It is desirable. When the volume resistivity of the entire layer structure of the charging member is less than 1 × 10 ⁵ Ωcm, a leak may occur. On the other hand, when the volume resistivity exceeds 1 × 10 ¹⁰ Ωcm,
Poor charging may occur.

Here, the volume resistivity of the entire layer structure of the charging member refers to the entire volume resistivity of the charging member except for the core material, on which all the constituent layers are formed. In the case of a two-layer structure composed of only the elastic layer and the surface layer, the volume resistivity is the total of the two layers, and in the case of including other layers such as an intermediate layer and an adhesive layer, these layers are also included. Volume resistivity of all layers.

The volume resistivity of the entire layer structure of the charging member can be determined by separately preparing a sheet-shaped measurement sample formed in the same manner as all the layers formed on the charging member to be measured, or by using a completed charging member. Then, all the layers are cut out to prepare a measurement sample in the form of a sheet, and the measurement can be performed in the same manner as the conductive elastic layer and the surface layer.

<Core Material> In the present invention, as the core material,
Conventionally known metals such as iron, nickel-plated iron, copper, and stainless steel can be used. As the shape of the core material,
In general, it is generally a shaft shape used as a core material of a charging member.

<Conductive Elastic Layer> In the present invention, the conductive elastic layer is made of an elastic substance having conductivity, and
It satisfies the above-mentioned specification of volume resistivity. The material and composition are not particularly limited as long as such a material is used, but usually, a conductive material is dispersed and blended in a base material serving as a base. Examples of the conductive substance include an organic ion conductive substance, carbon black, and a metal oxide. In the present invention, the conductive material used for the conductive elastic layer is particularly preferably an organic ion conductive material from the viewpoint of resistance uniformity and leak resistance.

As the organic ion conductive substance, quaternary ammonium salts (for example, lauryl trimethyl ammonium,
Perchlorates such as stearyltrimethylammonium, octadodecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, denatured fatty acid and dimethylethylammonium, chlorate, borofluoride, sulfate, ethosulfate, halogen Benzyl salts (benzyl bromide salts, benzyl chloride salts, etc.), aliphatic sulfonates, higher alcohol sulfates, higher alcohol ethylene oxide addition sulfates, higher alcohol phosphates,
Higher alcohol ethylene oxide addition phosphoric acid ester salts, various betaines, higher alcohol ethylene oxide, polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid esters, and the like.

Examples of the organic ion conductive substance include polyhydric alcohols (1,4 butanediol, ethylene glycol,
Complexes of polyethylene glycol, propylene glycol, polyethylene glycol and the like and derivatives thereof with metal salts, and complexes of monools (such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether) with metal salts are also included. Examples of the metal salt include Li
ClO ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiBF ₄ ,
NaClO ₄ , NaSCN, KSCN, NaCl, etc., Group 1 metal salts of the periodic table; electrolytes, such as NH ⁴⁺ salts;
(ClO ₄ ) ₂ , Ba (ClO ₄ ) ₂ etc., a metal salt of Group 2 of the periodic table; active hydrogen which reacts with isocyanate such as at least one or more hydroxyl group, carboxyl group, primary or secondary amine group Having a group having the formula: Specifically, as such a complex, PEL (L
complex of iClO ₄ and polyethylene glycol).

Of these, a quaternary ammonium salt is preferable as the organic ion conductive substance from the viewpoint of compatibility with the base material. The quaternary ammonium salt has a weight average molecular weight (Mw) of 1 from the viewpoint of bleeding and charging characteristics.
The number is preferably from 00 to 600, and more preferably from 150 to 300. As the quaternary ammonium salt, those having one or more benzene rings are particularly preferable from the viewpoint of bleeding and charging characteristics as described above.

Preferred organic ion conductive materials include quaternary ammonium salts represented by the following general formula (I).

[0027]

Embedded image

In the above formula, R ¹ , R ² and R ³ are each independently hydrogen or a hydrocarbon group which may contain a substituent, preferably hydrogen, an alkyl group having 1 to 20 carbon atoms, 6 to 10 aryl groups or 7 to 2 carbon atoms
0 is an alkylaryl group. T represents a linking group containing a single bond, preferably a single bond or a group having 1 carbon atom.
To 5 alkylene groups. Hereinafter, specific examples of suitable quaternary ammonium salts will be shown, but the present invention is not limited thereto.

[0029]

Embedded image

Examples of the metal oxide used as the conductive material include zinc oxide, titanium oxide, tin oxide, and antimony-doped tin oxide. Note that carbon black used as a conductive substance is preferably used in a surface layer described below, and thus will be described in detail in the section of the surface layer.

The base material of the conductive elastic layer is not particularly limited, and conventionally known materials can be used. For example, polyimide, polyester, polyether ether ketone, polyamide, polycarbonate, polyvinylidene fluoride (PVDF) ), Resin materials such as polyfluoroethylene-ethylene copolymer (ETFE); polyurethane,
Elastic materials such as chlorinated polyisoprene, acrylonitrile butadiene rubber (NBR), chloropyrene rubber, ethylene propylene diene rubber (EPDM), hydrogenated polybutadiene, butyl rubber, silicone rubber, acrylic rubber, and epichlorohydrin rubber; Thermoplastic elastomers, heat-shrinkable (thermosetting) rubbers, foamable rubbers, and non-diene-based rubbers irrespective of the diene type as described above can also be suitably used. These can also be used as an alloy (blend material) in which two or more kinds are blended.

Among the above, the base material of the conductive elastic layer is preferably composed mainly of epichlorohydrin rubber in terms of resistance uniformity and resistance stability. In addition,
The phrase “mainly composed of epichlorohydrin rubber” means that the main component of the base material component is epichlorohydrin rubber, and those that account for 50% by weight or more of the base material component are included in the concept of “mainly composed of”. include.

The base material of the conductive elastic layer preferably contains epichlorohydrin rubber as a main component and further contains 1 to 5% by weight of a second rubber component. By containing the second rubber component, workability such as formation and polishing is remarkably improved. If the second rubber component is less than 1% by weight, the effect of containing the second rubber component cannot be obtained, and if the second rubber component exceeds 5% by weight, the resistance uniformity becomes poor,
Image quality defects are likely to occur. As the second rubber component, any of the rubber materials described above as the material of the base material can be used. In particular, nitrile butadiene rubber (NB)
It is preferable to use R) in terms of uniformity of resistance, chargeability, and workability.

The conductive material may be used alone in the base material, but may be used in combination of two or more kinds.
In addition to electrical resistance (surface resistivity, volume resistivity), mechanical strength,
It can be blended to meet the requirements of the whole system such as hardness and rebound resilience. The amount of the conductive substance to be added to the substrate may be appropriately adjusted so as to satisfy the above-described regulation of the volume resistivity, but is preferably 0.01 to 200 phr.
("Phr" means parts by weight based on 100 parts by weight of the base material)
It is generally preferred that the amount is 0.01 to 20 phr for a salt alone and 200 phr or less for a metal oxide.

In the conductive elastic layer, a curing agent, a plasticizer, a vulcanization accelerator and the like may be used, if necessary, in addition to the base material and the conductive material. In the case of foaming, a foaming agent or the like can be appropriately used. The thickness of the conductive elastic layer is not particularly limited, but is preferably about 1 to 10 mm, and more preferably about 2 to 5 mm.

The conductive elastic material layer is formed by dissolving the base material, the conductive material, and other substances added as necessary in a suitable solvent and applying the resulting solution to a core material. Can be formed by kneading a compound with a base material and forming a compound, winding the material around a core material and pressing, or by a known molding method such as injection molding. In the case of forming by applying, it is desirable to apply the layers repeatedly to secure a predetermined thickness.

<Surface Layer> In the present invention, the surface layer is a layer which functions not only to adjust the resistance but also to block the bleed material from the elastic layer and to protect it from contaminants. It is made by dispersing an active substance. Examples of the conductive substance include an organic ion conductive substance, carbon black, and a metal oxide.

As the organic ion conductive substance and the metal oxide as the conductive substance, the same ones as described in the section of the conductive elastic layer can be used. In addition, carbon black can be used in the conductive elastic layer, but the control of dispersion in the elastic layer, the uniformity of resistance,
It is difficult to obtain stability, and it is preferable to use it as a reinforcing agent. In addition, carbon black is preferably used for the surface layer in the present invention since bleeding does not occur.

The pH of the carbon black is preferably not more than 6.0, more preferably not more than 5.0, even more preferably not more than 4.5. here,
The pH is a physical property value of carbon black and is defined as follows (for details, see JIS K6221-1982).
According to). The term “pH” refers to the pH (logarithmic value of hydrogen ion concentration) measured for a mud obtained by boiling carbon black with water, cooling, and removing the supernatant. It is related to the amount of oxygen-containing functional groups (each functional group such as carboxylic acid, hydroxyl, lactone and quinoid) on the surface of carbon black,
It is considered that the lower the pH is, the more acidic surface functional groups are (see "Carbon Black Handbook" edited and published by Carbon Black Association of Japan, 1995). In addition, there is a volatile component as a physical property value indicating the amount of the oxygen-containing functional group on the carbon black surface. This volatile matter is defined as 950 ± 2 carbon black.
The percentage of weight loss when held in a 5 ° C. atmosphere for 7 minutes is expressed as a percentage. Generally, carbon black having a lower pH tends to have more volatile components, and it is sufficient to specify either one. Conceivable.

By using carbon black as a conductive substance, an excessive current flows partially, and is less susceptible to oxidation by repeated voltage application, and furthermore, due to the effect of oxygen-containing functional groups attached to the surface, It has high dispersibility to the base material and can reduce resistance variation,
Electric field dependence is also reduced, and electric field concentration due to energization is less likely to occur. As a result, resistance change due to energization is prevented, uniformity of electric resistance is improved, electric field dependence is small, and resistance change due to environment is small, and uniform charging is possible. For this reason, it is possible to prevent electric field concentration caused by large aggregates of carbon black and leakage discharge such as pinhole leak, which is considered to be caused by dielectric breakdown, and also prevent toner from sticking. Further, image quality defects caused by uneven charging and leak discharge due to resistance change and resistance variation, and fluctuations in image density due to environmental fluctuations are reduced, and high-quality images can be obtained over a long period of time.
In addition, carbon black does not require a coupling treatment for improving dispersibility, addition of insulating particles, metal oxides, or the like, and the manufacturing process is simplified. further,
Since carbon black is electronically conductive, there is no problem of bleeding using ionic conductivity, for example, an ionic conductive material that contains an ether segment and tends to contaminate the image carrier. Accordingly, there is no need to provide a layer or the like for preventing bleeding, and the manufacturing process is similarly simplified.

The carbon black is preferably acidic, and the surface thereof has a large amount of oxygen-containing functional groups (such as carboxylic acid groups, hydroxyl groups (for example, phenol hydroxyl groups), lactone groups, and quinoid groups). Generally, the oxygen-containing functional group on the surface of carbon black imparts polarity to carbon black consisting only of carbon, improves affinity with a base material (binder polymer), and enables uniform dispersion.・ While widely recognized in systems containing solvents such as paints, it is presumed that this is true even when kneading and dispersing in a dry system.

[0042] Carbon black can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Carbon black can also be produced by a furnace black method using gas or oil as a raw material. If necessary, after these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. Note that carbon black can be produced by a contact method, but this contact method is hardly produced at present due to problems such as air pollution, and is usually produced by a closed furnace method. In the furnace method, only carbon black having a high pH and a low volatile content is usually produced, but the pH can be adjusted by subjecting the carbon black to the above-mentioned liquid acid treatment. Therefore, the carbon black obtained by the furnace method may be adjusted to have a pH of 6 or less by post-processing.

As carbon black, specifically, "MA100" (3.5, volatile matter 1.5 by Mitsubishi Chemical Corporation)
%), The same "MA100R" (pH 3.5, volatile matter 1.5
%) And "MA100S" (pH 3.5, volatile matter 1.5
% #) And "# 970" (pH 3.5, volatile content 3.0)
%, The same “MA11” (pH 3.5, volatile content 2.0)
% "And"# 1000 "(pH 3.5, volatile content 3.0)
%) And "# 2200" (pH 3.5, volatile matter 3.5)
%) And "MA230" (pH 3.0, volatile matter 1.5
%) And "MA220" (pH 3.0, volatile matter 1.0)
%) And "# 2650" (pH 3.0, volatile matter 8.0)
%), "MA7" (pH 3.0, volatile content 3.0%),
"MA8" (pH 3.0, volatile content 3.0%), "O8"
IL7B "(pH 3.0, volatile content 6.0%)," MA
77 "(pH 2.5, volatile content 3.0%) and"# 235
0 "(pH 2.5, volatile content 7.5%) and"# 270
0 "(pH 2.5, volatile content 10.0%) and"# 240
0 "(pH 2.5, volatile content 9.0%);" Color Black FW1 "manufactured by Degussa (pH 4.5, volatile content 5.0
%), "Color Black FW18" (pH 4.5, volatile content 5.0%), "Color Black S170" (pH
4.5, volatile content 5.0%)
0 "(pH 4.5, volatile content 5.0%)," Printex U "(pH 4.5, volatile content 5.0%)," Printex V "(pH 4.5, volatile content 5.0) %) And "Printex 140U" (pH 4.5, volatile matter 5.0)
%), "Printex 140V" (pH 4.5, volatile content 5.0%), "Printex 150T" (4.
0, volatile content 10.0%) and “Special Black 35”
0 "(pH 3.5, volatile content 2.2%)," Special Black 100 "(pH 3.3, volatile content 2.2%)," Special Black 250 "(pH 3.1, volatile content 2.0%) %) And "Special Black 5" (pH 3.
0, volatile content 15.0%), "Special Black 4"
"Special Black 4A" (pH 3.0, volatile content 14.0%), "Special Black 550" (pH 2.8, volatile content 2.5%) And “Special Black 6” (pH 2.
5, volatile matter 18.0%), and “Color Black FW20”
0 "(pH 2.5, volatile matter 20.0%)," Color Black FW2 "(pH 2.5, volatile matter 16.5%)," Color Black FW2V "(pH 2.5, volatile matter 1
6.5%), “MONARCH100” manufactured by Cabot Corporation
0 "(pH 2.5, volatile matter 9.5%)," MONAR
CH1300 "(pH 2.5, volatile content 9.5%), and" MONARCH 1400 "(pH 2.5, volatile content 9.5%).
0%), “MOGUL-L” (pH 2.5, volatile content 5.0%), “REGAL400R” (pH 4.0,
Volatile content 3.5%);

The above-mentioned conductive substance may be used alone in the substrate, but any two or more kinds may be used.
In addition to electrical resistance (surface resistivity, volume resistivity), mechanical strength,
It can be blended to meet the requirements of the whole system such as hardness and rebound resilience. The amount of the conductive substance to be added to the base material may be appropriately adjusted so as to satisfy the above-described regulation of the volume resistivity, and is 1 to 100 phr (“p
It is generally preferred that "hr" be about the same as the number of parts by weight per 100 parts by weight of the base material.

As the base material of the surface layer, the same materials as those described in the section of the conductive elastic layer can be used. In the surface layer, the aliphatic polyester resin is subjected to a crosslinking reaction with the melamine resin. It is desirable to use a thermosetting resin in terms of film strength and bleed.

The mixing ratio of the melamine resin to the aliphatic polyester resin is 100 to 100 parts by weight.
It is preferably 0 parts by weight, more preferably 40 to 60 parts by weight. When the amount of the melamine resin is less than 30 parts by weight, an uncrosslinked portion remains, and the obtained surface layer is sticky and easily tacky to the photoreceptor. When the amount exceeds 70 parts by weight, the degree of crosslinking may be high. The surface layer is brittle, hard, and easily cracks, which are not preferred.

When the above-mentioned thermosetting resin is used as the base material of the surface layer, the surface layer further contains a fluorine-based polymer compound and / or a silicone-based polymer compound. It is desirable in terms of prevention and resistance to environmental stability.

The content of the fluorine-based polymer and / or the silicone-based polymer is preferably in the range of 5 to 100 parts by weight based on 100 parts by weight of the thermosetting resin. More preferably, it is in the range of 80 to 80. If the content is less than 5 parts by weight, the effect of the inclusion cannot be obtained, and if it exceeds 100 parts by weight, the processability is remarkably reduced, the film becomes brittle, and the effect of increasing the amount of toner to prevent toner adhesion is also reduced. Almost no, just undesirably expensive. .

The surface layer is formed by dissolving the above-mentioned base material, the above-mentioned conductive substance, and other substances added as necessary in a suitable solvent, and applying the resulting solution to the core material. It can be formed by winding the compound kneaded and compounded with a core material and pressing it, or by a known molding method such as injection molding. In the case of forming by applying, it is desirable to apply the layers repeatedly to secure a predetermined thickness. When a thermosetting resin is used as the base material, it is preferable to heat at a temperature sufficient for curing after coating or molding.

<Application of the Present Invention> The charging member of the present invention described above is used for a copying machine, a laser printer, a facsimile,
It is suitably used as a charging member in a contact-type charging system charger in an electrophotographic apparatus such as a composite OA apparatus.

An electrophotographic apparatus to which the charging member of the present invention is suitably applied will be described in detail with reference to the drawings. FIG.
FIG. 1 is a schematic cross-sectional view illustrating an example of an electrophotographic apparatus to which the charging member of the present invention is applied. The electrophotographic apparatus shown in FIG.
An electrophotographic photoreceptor 10; a charger 11 comprising the charging member of the present invention for charging the surface of the electrophotographic photoreceptor 10; a power supply 12 for applying a voltage to the charger 11; An image input device 13 for forming a latent image on the surface of the electrophotographic photoreceptor 10 with a toner, and a developing device 14 for developing a latent image formed on the surface of the electrophotographic photosensitive member 10 to obtain a toner image. , A cleaner 16 for removing residual toner and the like on the surface of the electrophotographic photoreceptor 10, a static eliminator 17 for removing residual potential on the surface of the electrophotographic photoreceptor 10, and a transfer to the surface of the transfer-receiving body 20 And a fixing device 18 for fixing the formed toner image by heat and / or pressure.

The charger 11 comprising the charging member of the present invention
It operates by the voltage supplied from the power supply 12, and charges the surface of the photoconductor. In addition, an image input device 13, a developing device 14, a transfer device 15, a cleaning device 16, a static eliminator 17, and a fixing device 1
The configuration 8 is not particularly limited in the present invention, and any configuration conventionally known in the field of electrophotography can be applied as it is. Note that the static eliminator 17 is not necessarily provided.

The operation of the electrophotographic apparatus shown in FIG. 1 will be described. The surface of the electrophotographic photosensitive member 10 is uniformly charged by the charger 11, and then a latent image is formed by the image input device 13. The latent image formed on the surface of the electrophotographic photoreceptor 10 is developed by a toner built in the developing device 14 to form a toner image. The toner image formed on the surface of the electrophotographic photoreceptor 10 is transferred to the surface of the transfer receiving member 20 inserted between the electrophotographic photoreceptor 10 and the transfer unit 15 facing the electrophotographic photoreceptor 10. And / or fixed by pressure or the like. On the other hand, the transferred electrophotographic photoreceptor 10
The residual toner on the surface is removed by the cleaning device 16. Then, before proceeding to the next image forming cycle, the residual potential on the surface of the electrophotographic photosensitive member 10 is removed by the neutralizer 17.

[0054]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. <Manufacture of charging member> As core material, length 331 mm, 8 m
A stainless steel mφ was prepared. On this core material, a conductive elastic layer and a surface layer having the respective compositions and film thicknesses shown in Table 1 below were sequentially formed, and Examples 1 to 7 and Comparative Examples 1 to 5 were formed.
Were manufactured.

[0055]

[Table 1]

The conductive elastic layers and surface layers in Examples 1 to 8 and Comparative Examples 1 to 4 were formed as follows. (Conductive Elastic Layer) The materials for forming the conductive elastic layer shown in Table 1 above were kneaded by an open roll, and a roll having a diameter of 15 mm was obtained by using a press forming machine.
Finished to 4 mmφ.

(Surface Layer) A solution for forming a surface layer was prepared by uniformly dispersing the materials for forming a surface layer shown in Table 1 above using a dyno mill. Each of the obtained surface layer forming solutions was applied by dipping, and heated and fired at 160 ° C./30 minutes to form each surface layer having the thickness shown in Table 1.

<Measurement of Volume Resistivity> In the same manner as in <Production of Charging Member>, only the conductive elastic material layer, only the surface layer, and the conductive elastic material layer and the surface layer were made of the same material and had the same thickness. A sample formed in a sheet shape was prepared.

For each of the obtained samples, a circular electrode shown in FIG. 2 (HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: 16 mmφ in outer diameter of cylindrical electrode portion C, 30 mmφ in inner diameter of ring-shaped electrode portion D, Outer diameter of 40 mmφ) and 2
Under a 2 ° C./55% RH environment, a voltage of 100 V is applied,
The current value after seconds was determined, and each volume resistivity was determined. Result is,
It is as shown in Table 2 below.

[0060]

[Table 2]

<Evaluation Test> Fuji Xerox Co
An evaluation test of the charging member was performed by replacing the charging member of lor Laser Wind 3310 with each of the obtained charging members of Examples 1 to 7 and Comparative Examples 1 to 5, and performing image formation. Evaluation items and evaluation contents are as follows. The results obtained are shown in Table 3 below.

(Leak Resistance) Fuji Xerox C
In the photoconductor of color Laser Wind 3310, a hole of 0.2 mmφ is made until reaching the aluminum base material,
The halftone was printed out, the image quality was visually observed, and the leak resistance was evaluated. The evaluation indices are as follows. ：: Black spots of φ1 mm or less are generated in print image quality Δ: Black spots of φ3 mm or less are generated in print image quality X: Horizontal stripes are generated or BCR is broken

(Power Supply Capacity) Fuji Xerox Co
lor Laser Wind 3310, connected to an external power supply Trec 615, and a predetermined AC current of 1.2 m
The voltage Vpp required for flowing A was measured. Power supply capacity Vp
Since the maximum output of p is 2.7 kV, charging failure occurs at 2.7 kV or more. Therefore, the evaluation index was evaluated as ○ when the power supply capacity Vpp was less than 2.7 kV and as × when the power supply capacity was 2.7 kV or more.

(Image Quality) Fuji Xerox Colo
The image quality was evaluated by printing out three sheets each of blank paper and halftone using r Laser Wind 3310. The evaluation indices are as follows. ：: No fog occurred, ghost level 2 or less ×: Fog occurred, ghost level 3 or more

[0065]

[Table 3]

[0066]

As described above, according to the present invention, it is possible to provide a charging member having both good charging performance and leak resistance.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an electrophotographic apparatus to which a charging member of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electrophotographic photoreceptor 11 Charging device 12 Power supply 13 Image input device 14 Developing device 15 Transfer device (transfer member) 16 Cleaning device 17 Static eliminator 18 Fixing device 20 Transfer object

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16C 13/00 F16C 13/00 BE // (C08L 71/03 (C08L 71/03 9:02) 9 : 02) (72) Inventor Hisashi Akabane 1600 Takematsu, Minamiashigara, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masato Ono 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. Suzuka Fuji Xerox Co., Ltd. (72) Inventor Nobuaki Sugaya 1900, Ifuna-cho, Suzuka City, Mie Prefecture Suzuka Fuji Xerox Co., Ltd. In-house (72) Inventor Hideo Nishinomiya 1900, Ifuna-cho, Suzuka-shi, Mie F-term in Suzuka Fuji Xerox Co., Ltd. HA60 4F100 AA37H AH03B AH03H AK17C AK27B AK27J AK29B AK29J AK52C AK54B AL01B AL09B AN02B AR00C AT00A BA03 BA07 BA10A BA10C BA26B BA26C DE01C GB41 JA20C JG01B JG01C JG01H JG03 JG04 JG10 YY00 YY00B YY00C YY00H 4J002 AC072 CH041 DE196 DG046 DK006 EB126 EB136 EC076 EH046 EN136 EV186 EV256 EW046 FD116 GF00 GM00

Claims (10)

[Claims] 1. A charging member having a layer structure in which at least a conductive elastic layer and a surface layer in which a conductive substance is dispersed are sequentially laminated on a core material, wherein the conductive elastic layer is The volume resistivity is 1 × 10 ⁷ Ωcm or less, and the volume resistivity of the surface layer is one of the volume resistivity of the conductive elastic layer.
0 to 1 × 10 ⁶ times, and the volume resistivity of the entire layer structure of the charging member is 1 × 10 ⁵ to 1 ×.
A charging member having a resistivity of 10 ¹⁰ Ωcm. 2. The method according to claim 1, wherein the conductive material contained in the surface layer is p-type.
The charging member according to claim 1, wherein the charging member is a carbon black having an H of 6.0 or less. 3. The charging member according to claim 1, wherein the surface layer further contains a fluorine-based polymer compound and / or a silicone-based polymer compound. 4. The charging member according to claim 1, wherein the thickness of the surface layer is in a range of 1 to 50 μm. 5. The charging member according to claim 1, wherein the conductive elastic layer mainly comprises epichlorohydrin rubber. 6. The charging member according to claim 5, wherein the conductive elastic layer further contains 1 to 5% by weight of a second rubber component. 7. The charging member according to claim 6, wherein the second rubber component is a nitrile butadiene rubber. 8. The charging member according to claim 1, wherein the conductive elastic body layer further contains a conductive substance. 9. The charging member according to claim 8, wherein the conductive material contained in the conductive elastic layer is an organic ionic conductive material. 10. The charging member according to claim 9, wherein the conductive substance contained in the conductive elastic layer is a quaternary ammonium salt having a benzene ring.