JP2002132020A - Rubber composition for conductive roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a conductive roller which has small hardness and superior workability in manufacture, is satisfactory in compression permanent distortions, is small in surface roughness after surface polishing and has stable and low electrical resistance. SOLUTION: The rubber composition used for an elastic layer of the conductive roller, having the elastic layer on at least the outer periphery of a conductive shaft body, is composed of epichlorhydrin-base rubber of >=36 mol% in the ratio of an ethylene oxide copolymer as a chief raw material and contains at least a quaternary ammonium salt, which is an ion conducting agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a conductive roller, and more particularly to a rubber composition for a conductive roller such as a charging roller and a developing roller arranged in contact with a photoreceptor in an image forming apparatus such as an electrophotographic apparatus. And a rubber composition for a conductive roller.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, the surface of a photosensitive member is uniformly charged, and an image is projected on the photosensitive member from an optical system to irradiate light. A latent image is formed by erasing the charge of a portion, and then a toner image is formed (development) by attaching toner, and the toner image is transferred to a recording medium such as paper to perform printing.

As means for uniformly charging the surface of the photoreceptor, a charging member to which a voltage (for example, 1 to 2 kV) is applied is brought into contact with the photoreceptor with a predetermined pressing force to bring the photoreceptor to a predetermined potential. A contact charging system for charging is known. Among the contact charging methods, the charging roller is an important point for uniform charging by the contact charging method, and uniform contact with the photoreceptor is made by two rotating cylinders, so brush charging and blade charging etc. It is easier to realize than other contact charging methods and is adopted.

Since the charging roller is in contact with the photoreceptor, good releasability from the surface of the photoreceptor and releasability from the toner are also required. Furthermore, the charging roller is required to maintain a uniform nip width for uniform charging by contact with the photoreceptor. Therefore, appropriate charging (flexibility) and compression force due to contact are required. Must have sufficient resilience. A charging roller having two layers, a low hardness elastic layer on the outer periphery of the conductive shaft and a surface layer covering the surface of the low hardness elastic layer, in order to achieve both the releasability of the surface of the photoconductor and the toner and flexibility. It has been known.

[0005] Further, since the charging roller charges the photosensitive member in contact as described above, if the charging roller is electrically non-uniform or if the surface of the charging roller is uneven,
Charging density unevenness that reflects the electric non-uniformity and the surface irregularities occurs. Therefore, the charging roller has a predetermined resistance, is electrically uniform, and has a surface roughness (R
z) is required to be small.

In the formation (development) of a toner image by the adhesion of the toner, one of the methods for developing a non-magnetic one-component toner includes a photoconductor and a toner carrier for carrying a toner charged to a predetermined polarity. Develop by direct contact. The so-called contact development method is widely used. A developing roller is used as the toner conveying body. In order to obtain a uniform nip width by contact, the developing roller needs to have appropriate hardness (flexibility) and sufficient recovery from the compressive force due to contact. It is also required that the surface of the developing roller has good releasability from the toner and that the toner does not film on the roller surface. Further, it is required to have an appropriate surface roughness in order to obtain a uniform toner thin film on the surface of the developing roller. A developing roller having a low hardness elastic layer on the outer periphery of a conductive shaft and a surface layer covering the surface of the low hardness elastic layer has been known in order to achieve both releasability and flexibility for the toner. I have.

[0007]

In response to these requirements for a conductive roller such as a charging roller or a developing roller which is disposed in contact with a photoreceptor in an image forming apparatus such as an electrophotographic apparatus, the low-hardness elastic body has been developed. Conductive rubber is used. To obtain this low-hardness conductive rubber, ethylene-propylene rubber, styrene-
There is known a polymer in which a conductive filler such as carbon black is added to a polymer such as butadiene rubber, and a large amount of a softening agent is further added to obtain a low hardness. However, in the resistance adjustment by the conductive filler, the resistance value greatly fluctuates in a state where the conductive filler is present in the rubber, and is electrically non-uniform. Also, the addition of a large amount of a softening agent for lowering the hardness tends to deteriorate the compression set (recovery of the shape upon contact). As a measure against the electric non-uniformity, the rubber itself has a low resistance to some extent, for example, by using a conductive rubber composition using nitrile butadiene rubber (NBR) or epichlorohydrin-based rubber. It is also known that a conductive rubber having excellent properties can be obtained. However, nitrile-butadiene rubber (NBR) has a volume resistivity of about 2 × 10 ⁹ to 1 × 10 ¹⁰ Ω · cm of a vulcanized product, and is known to be a polymer having a low resistance value among various rubbers. In the case of epichlorohydrin rubber, the vulcanizate has a volume resistivity of about 5 × 10 ^{7 to} 3 × 10 ⁹ Ω · cm. However, the volume resistivity required for the material of the elastic layer of the conductive roller such as the charging roller and the developing roller is often about 1 × 10 ^{4 to} 5 × 10 ⁷ Ω · cm. Rubber (NBR)
In the case of a rubber composition composed solely of epichlorohydrin rubber or epichlorohydrin rubber, conductivity is often insufficient. Furthermore, when a plasticizer is added using a nitrile-butadiene rubber (NBR) or an epichlorohydrin rubber to obtain a low-hardness conductive elastic body, the plasticizer migrates to the surface layer of the low-hardness elastic body, and And the compression set tends to deteriorate. In order to obtain a conductive elastic body having a low hardness without containing a plasticizer, the crosslink density must be low. Alternatively, there is a method of preparing a rubber composition containing no filler or adding a small amount of filler. However, rubber having a low cross-linking density has poor compression set, and a rubber composition containing no filler or having a small amount of filler added has poor rubber kneading and extrusion processability and is not practical. Further, if a plasticizer is not used, it is difficult not only to reduce the hardness but also to deteriorate the roll workability in rubber kneading and the extrusion workability in preforming. Furthermore, low hardness rubbers generally have poor surface grindability and tend to have poor surface roughness (Rz) after surface polishing for obtaining a predetermined outer diameter and shape.
In addition, in the vulcanization of epichlorohydrin rubber, as an acid acceptor that adsorbs hydrochloric acid gas generated during crosslinking,
In many cases, lead compounds such as red lead are blended, and there is a problem in safety such as toxicity.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image forming apparatus such as an electrophotographic apparatus having an elastic layer at least on the outer periphery of a conductive shaft. In a rubber composition for a conductive roller used for an elastic layer of a conductive roller such as a charging roller or a developing roller disposed in contact with a photoconductor, a vulcanized product of the rubber composition has a low hardness and a permanent compression. Excellent in distortion, excellent in electrical uniformity, excellent in grindability, small in surface roughness after polishing, and the rubber composition in an unvulcanized state has good rubber kneading workability and extrusion workability, and An object of the present invention is to provide a rubber composition for a conductive roller containing no lead compound.

[0009]

In order to achieve the above object,
The present invention provides a rubber composition for a conductive roller used for the elastic layer of a conductive roller having an elastic layer on at least the outer periphery of a conductive shaft, wherein the rubber composition comprises epichlorohydrin rubber (A component). As a main raw material, it contains at least a sub (B component) and an ion conductive agent (C component).

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a charging roller, a developing roller, and the like.
Volume specificity required for the material for the elastic layer of the conductive roller
Resistance is 1 × 10^Four~ 5 × 10⁷Many are about Ωcm
Therefore, epichlorohydrin, a low-resistance polymer,
Rubber-based rubber is used as the main raw material. Also, epichlorohydride
Phosphorus rubber alone has insufficient conductivity, and ionic conductivity
The conductivity is improved by using an agent. As an ion conductive agent
Is LiClO_Four, LiCF_ThreeSO_Three, LiBF_Four, L
iN (CF_ThreeSO_Three)_Two, NaClO_FourLi⁺, N
a ⁺Metal salts such as tetraethylammonium perchlorate,
Tetrabutylammonium perchlorate, tetramethyl chloride
Ammonium, tetraethylammonium chloride,
Trabutylammonium, tetramethylammonium bromide
System, tetrapropylammonium bromide, tetrame iodide
Quaternary ammonium salts such as tyl ammonium
It is. Even if these ionic conductive agents are used alone, two or more
May be used in combination. In addition, it contains an ion conductive agent
Epichlorohydrin rubber has poor processability in production,
If the hardness is low, the surface roughness after surface polishing is inferior,
The strain is not good. Epi containing these ionic conductive agents
The problem with chlorohydrin rubber is that the sub (component B) is added.
It is greatly improved by adding.

That is, according to the present invention, low elasticity required for an elastic body of a conductive roller such as a charging roller or a developing roller, excellent workability in production, good compression set, small surface roughness, and low Is obtained.

Another embodiment of the present invention is a three-dimensional crosslinked oil wherein the sub-component (B) does not contain sulfur and chlorine, and the sub-component (B) is 10 parts by mass with respect to 100 parts by mass of epichlorohydrin rubber (A component). １００100 parts by mass.

The sub (B component) is also called factice,
Softeners for rubber, known as processing aids, include black sub and golden factice containing sulfur and cross-linked vegetable oil, etc., and white sub and candy sub containing sulfur chloride and cross-linked vegetable oil etc. Commonly used. By adding such a sub-component (B), an elastic body having good workability and excellent grinding properties can be obtained as compared with the case where a plasticizer is used. By using the sub-component (B) which is a three-dimensional crosslinked oil containing no sulfur and chlorine, the processability is further improved, and an elastic body having excellent compression set can be obtained. The reason for this is that sulfur (B) containing chlorine or chlorine (B
Component) is present in the compressed state for a long period of time, so that crosslinking is more likely to proceed in the compressed state due to the action of existing sulfur or sulfur chloride, which affects the deterioration of compression set. In the sub-component (B) that does not contain sulfur and chlorine, the fact that the substance that promotes crosslinking is reduced and the cross-linking of the sub-component (B) itself is strong are considered to be factors that reduce the compression set. The sub (component (B)) containing no sulfur and chlorine is 10 to 100 parts by mass based on 100 parts by mass of the epichlorohydrin rubber.
It is contained by mass. When the added amount of this sub (B component) is 10
If the amount is less than 100 parts by mass, the effect of improvement is small. If the amount is more than 100 parts by mass, the effect of improving the surface roughness after surface polishing is lost, and the compression set is deteriorated. Preferably, the added amount of the sub-component (B component) containing no sulfur and chlorine is 20 to 100 parts by mass.

That is, according to the present invention, it is possible to obtain a conductive roller which is excellent in workability in production, has small surface roughness after surface polishing, and has good compression set.

According to another aspect of the present invention, the epichlorohydrin rubber (component A) is a copolymer of epichlorohydrin-ethylene oxide-allyl glycidyl ether, or a copolymer of epichlorohydrin-ethylene oxide, or a mixture thereof. It is a mixture, and the ethylene oxide copolymerization ratio in the whole epichlorohydrin rubber is 36 mol% or more.

The epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer or the epichlorohydrin-ethylene oxide terpolymer is
As the copolymerization ratio of ethylene oxide increases, the volume resistivity of the vulcanized rubber tends to decrease. For this reason, if the copolymerization ratio of ethylene oxide is less than 36 mol%, it becomes difficult to obtain an electric resistance value required for an elastic body of a conductive roller such as a charging roller or a developing roller, and the temperature dependence of the electric resistance becomes large. . Preferably, the ethylene oxide copolymerization ratio in the epichlorohydrin rubber is 3
8 to 58 mol%.

That is, according to the present invention, it is possible to obtain a conductive roller in which the elasticity of a conductive roller such as a charging roller or a developing roller is less dependent on the environment in terms of conductivity and electric resistance.

In another embodiment of the present invention, the ionic conductive agent (component C) is a quaternary ammonium salt, and the ionic conductive agent (component C) is 0.1 part by mass with respect to 100 parts by mass of epichlorohydrin rubber (component A). It is contained in an amount of 5 to 15 parts by mass.

A quaternary ammonium salt is used as an ionic conductive agent which is added to epichlorohydrin rubber to lower the electric resistance. By using a quaternary ammonium salt as the ion conductive agent, it is possible to obtain a conductive roller having small environmental dependence of electric resistance. The quaternary ammonium salt is not particularly limited, and various salts can be used. For example, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride And quaternary ammonium salts such as tetramethylammonium bromide, tetrapropylammonium bromide and tetramethylammonium iodide. These may be used alone or in combination of two or more. The quaternary ammonium salt is contained in an amount of 0.5 to 15 parts by mass based on 100 parts by mass of the epichlorohydrin rubber. When the amount of the quaternary ammonium salt is 0.5
If the amount is less than 15 parts by mass, the effect of lowering the electric resistance value is small, and if it is more than 15 parts by mass, the ionic conductive agent tends to bloom on the surface. Preferably, the addition amount of the quaternary ammonium salt is 1 to 8 parts by mass.

That is, according to the present invention, it is possible to obtain a conductive roller in which the elasticity of a conductive roller such as a charging roller or a developing roller is less dependent on the environment in terms of conductivity and resistance.

In another embodiment of the present invention, an epichlorohydrin rubber (A component), a sub (B component), an ionic conductive agent (C
And vulcanizates of rubber compositions containing 2,4,6-trimercapto-S-triazine (component D) as a vulcanizing agent in addition to component (1).

As the epichlorohydrin rubber (especially allyl glycidyl ether copolymer), various vulcanizing agents such as sulfur, sulfur-containing organic compounds and peroxides can be used. Elastic bodies using sulfur and sulfur-containing organic compounds have slightly lower compression set, and peroxides give better compression set, but vulcanization that requires mold vulcanization The method is limited, and the obtained electric resistance tends to be high, so that the method of use is often limited. By using 2,4,6-trimercapto-S-triazine as a vulcanizing agent, various vulcanizing methods can be adopted and a product having excellent compression set can be obtained.

That is, according to the present invention, it is possible to obtain a conductive roller having a good compression set while maintaining an electric resistance required for an elastic body of a conductive roller such as a charging roller or a developing roller.

In another embodiment of the present invention, the above epichlorohydrin rubber (component A), sub-component (B), ionic conductive agent (component C), 2,4,6-trimercapto-S-triazine (component D) In addition, 2 to 15 parts by mass of hydrotalcite (component E) as an acid acceptor is contained with respect to 100 parts by mass of the epichlorohydrin rubber (component A). When 2,4,6-trimercapto-S-triazine is used as a vulcanizing agent in the epichlorohydrin rubber, HCl gas is generated in the formation of triazine crosslinks by the chlorine extraction reaction of epichlorohydrin. It is necessary to add an acid acceptor for the purpose of adsorption. Lead acid (Pb ₃ O ₄ ), litharge (PbO) and the like have been blended as acid acceptors. Although it is said that lead tin and the like are easy to obtain in terms of vulcanization properties of the elastic body, it is desirable not to use it because it has problems of lead toxicity and environmental pollution. For this reason, studies have been made to use magnesium oxide as an acid acceptor. However, when magnesium oxide and 2,4,6-trimercapto-S-triazine are used in combination, hardness changes due to a slight difference in the amount of magnesium oxide added. Therefore, there are problems that the hardness tends to vary, the magnesium oxide has a high hygroscopicity, and the roll adhesion in the rubber kneading process of the hydrin-based rubber is slightly increased to deteriorate the processability. By using hydrotalcite as the acid acceptor, an epichlorohydrin-based rubber elastic body which does not use lead and has good processability can be obtained. Hydrotalcite is contained in an amount of 2 to 15 parts by mass based on 100 parts by mass of the epichlorohydrin rubber. If the added amount of hydrotalcite is less than 1 part by mass, a rapid vulcanization rate cannot be obtained, and the acid-accepting effect is too small, so that HC
There is a possibility that the 1-gas may not be completely absorbed, and even if it is added in an amount of more than 15 parts by mass, the compression set deteriorates.

That is, the present invention provides a rubber composition for an epichlorohydrin-based rubber elastic conductive roller which has a small environmental dependence of electric resistance, excellent workability, small variation in hardness and the like, and does not use a lead compound. Can be

The rubber composition used in the conductive roller of the present invention may contain various additives in addition to the above components. Examples of the additive include an antioxidant, a vulcanization accelerator, a reinforcing agent such as carbon black, a filler, and a processing aid. These additives may be used alone or in combination of two or more.

[0027]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

Tables 1 to 5 show the proportions of the rubber compositions used in the examples and comparative examples. The raw materials shown in Tables 1 to 5 were kneaded with an open roll to produce rubber compositions of Examples and Comparative Examples.

The materials used in the examples and comparative examples are as follows. Epichlorohydrin rubber [Epichlorohydrin 40 mol%, ethylene oxide 56 mol%, allyl glycidyl ether 4 mol
%; Trade name Zeklon 3106 manufactured by Nippon Zeon Co., Ltd.] [Epichlorohydrin 48 mol%, ethylene oxide 48 mol%, allyl glycidyl ether 4 mol]
%; Trade name Epichromer CG105 Daiso Corporation
[Epichlorohydrin 56 mol%, ethylene oxide 41 mol%, allyl glycidyl ether 3 mol]
%; Trade name Epichromer CG107 Daiso Co., Ltd.
[Epichlorohydrin 58 mol%, ethylene oxide 38 mol%, allyl glycidyl ether 3 mol]
%; Trade name Zeklon 3105 manufactured by Nippon Zeon Co., Ltd.] [Epichlorohydrin 62.5 mol%, ethylene oxide 35 mol%, allyl glycidyl ether 2.5
mol%; trade name Zeklon 3102 manufactured by Nippon Zeon Co., Ltd.] [epichlorohydrin 67 mol%, ethylene oxide 25 mol%, allyl glycidyl ether 8 mol
%; Trade name Zeklon 3100 manufactured by Nippon Zeon Co., Ltd.] nitrile butadiene rubber [NBR (bound acrylonitrile amount (AN) 33.5% by weight; trade name: Nipol 1042 manufactured by Nippon Zeon Co., Ltd.) Chlorine sub; trade name Lenoprene EPS
Bayer Co., Ltd.] [Sulfur-containing sub; trade name: Black sub pure type, manufactured by Tenma Sub-Kako Co., Ltd.] [Sulfur chloride-containing sub; trade name: White Sub 1; Tenma Sub-Kako Co., Ltd.] Sulfur conductive agent [Quaternary ammonium salt; trade name: KS-555, manufactured by Kao Corporation] [Tetraethylammonium perchlorate; Kanto Chemical Co., Ltd.]
[Lithium perchlorate; manufactured by Kanto Chemical Co., Ltd.] Acid acceptor [Hydrotalcite; trade name: DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd.] [Magnesium oxide; trade name: Kyowa Mag # 150 Kyowa Chemical Industry Co., Ltd.] Vulcanizing agent [2,4,6-trimercaptotriazine; trade name Disnet F manufactured by Nippon Zeon Co., Ltd.] [Sulfur; trade name Sulfax PMC Tsurumi Chemical Industry Co., Ltd.] Vulcanization accelerator [1,3 diphenylguanidine; trade name Noxeller D
Ouchi Shinko Chemical Co., Ltd.] [Dibenzothiazyl disulfide; trade name Noxeller DM manufactured by Ouchi Shinko Chemical Co., Ltd.] [Tetraethylthiuram disulfide; trade name Noxeller TET manufactured by Ouchi Shinko Chemical Co., Ltd.] [Dipentamethylene thiuram tetrasulfide; trade name Noxeller TRA manufactured by Ouchi Shinko Chemical Industry Co., Ltd.] [2- (4 'morpholinothio) benzothiazole; trade name Noxeller MBT manufactured by Ouchi Shinko Chemical Industry Co., Ltd. ] Vulcanization retarder [N-cyclohexylthiophthalimide; trade name retarder CTP manufactured by Ouchi Shinko Chemical Industry Co., Ltd.] Other materials [dioctyl phthalate; trade name DOP manufactured by Dainippon Ink and Chemicals, Inc.] [dioctyl seba] Gate; trade name DOS, manufactured by Dainippon Ink and Chemicals, Inc.] [Sebacic acid polyester; product Polycizer P
-202, manufactured by Dainippon Ink and Chemicals, Inc.] [Calcium carbonate; trade name: Silver W, manufactured by Shiraishi Kogyo Co., Ltd.] [Zinc oxide; trade name: Zinc flower 2 species Hakusui Chemical Co., Ltd.]
[Stearic acid; trade name: Stearic acid S Kao Corporation]
The test pieces and the conductive rollers of the examples and comparative examples were produced as follows.

Test Specimens: The rubber compositions of Examples and Comparative Examples were press-vulcanized to give a 2 mm sheet (vulcanized at 160 ° C. for 20 minutes) and a compression set test specimen (vulcanized at 160 ° C. for 25 minutes). Produced.

Conductive roller: After extruding the rubber composition into a tube shape using an extruder, the extruder is used in a vulcanizer at 160 ° C. × 3.
Vulcanization for 0 minutes to produce a rubber vulcanizate in the form of a tube,
Next, a conductive shaft having a diameter of 60 mm was press-fitted into the inner diameter of the rubber vulcanizate in the form of a tube to obtain a roller-shaped molded body. This compact was set in a polishing machine equipped with a polishing grindstone GC80, and polished so that the outer diameter was 12 mm at a rotation speed of 2000 RPM and a feed speed of 500 m / min.
A conductive roller was manufactured.

Further, properties relating to volume specific resistance, hardness, compression set, working accuracy, and roller surface roughness were measured by the following methods. <Workability> In each of the above Examples and Comparative Examples, the workability in each step of kneading, extrusion molding, vulcanization, etc. of the rubber material was comprehensively judged. Poor, although slightly worse, but practicable, and X, poor workability and unsuitable for practical use. <Volume resistivity> A 10 mm direct current voltage was applied to a 2 mm thick vulcanized rubber sheet sandwiched between electrodes with a guide ring, and the electrical resistance was measured. The environmental conditions are a low temperature / low humidity L / L environment (15 ° C. × 10% RH), a normal temperature / normal humidity N / N environment (23 ° C. × 50% RH), and a high temperature / high humidity H / H environment (3
(5 ° C. × 85% RH). <Hardness> The hardness was measured in accordance with JIS K-6253. <Compression set ratio> The compression set ratio is based on JIS K-6.
262 large specimen (diameter 29mm, thickness 12.5m)
m), the compression set after standing for 72 hours under the conditions of 40 ° C. × 85% RH × 25% compression was measured. <Roller Surface Roughness> The surface roughness (Rz) of each of the conductive rollers of the examples and comparative examples was measured using a surface roughness measuring device Surfcorder SE3500 manufactured by Kosaka Laboratory Co., Ltd., and the average value was measured. I asked. <Roller resistance> The roller resistance is determined by applying a pressure of 1 kg / cm ² on the shaft of the conductive roller to an aluminum drum having an outer diameter of 30 mm and pressing the shaft between the shaft and the aluminum drum. The measurement was performed by applying a voltage of 100V.

The results are shown in Tables 6-9.

The rubber compositions using the rubber compositions of Examples 1 to 12 have excellent workability in each step such as kneading, extrusion molding, and vulcanization of the rubber material, and have a specific volume resistivity measured with a vulcanized rubber sheet. The L / L environment and the H / H environment change by only about one order, the environment dependence is small, and the volume resistivity of the N / N environment is 1.8 × 10 ^{6 to} 1.2 × 10 ⁷ . It has a suitable electrical resistance. Further, the compression set was 11% or less in all cases and excellent in compression set, and the hardness was 45 or less, and the hardness was suitable. The roller surface roughness (Rz) after polishing was 4 μm or less, and the surface roughness was excellent. It has been found that a conductive roller having a suitable roller resistance can be obtained.

In Examples 13 and 14, the subs containing sulfur or chlorine were used instead of the subs in Example 2, and the compression set rates were 15% and 13%, respectively. Although it is somewhat inferior, it is a usable category,
Other properties are excellent, and a usable conductive roller is obtained.

In Example 15, the amount of addition of sulfur-free and chlorine-free sub was set to 9 parts by mass with respect to Example 1, and the extrudability was slightly inferior to Examples 1 to 12, but practical. This is a category, and other properties are excellent, and a usable conductive roller is obtained.

Example 16 differs from Example 1 in that the amount of sulfur-free and chlorine-free sub was 130 parts by mass, the compression set was 17%, and the roller surface roughness after polishing was as follows. Although (Rz) is 4.7 μm, which is slightly inferior to Examples 1 to 12, other characteristics are excellent, and a usable conductive roller is obtained.

In Example 17, an epichlorohydrin rubber having a smaller ethylene oxide content of 35 mol% than that of Example 2 was used, and the volume resistivity measured on a 2 mm sheet under an N / N environment was 2.8 ×. 10 ⁷ Ω · cm,
An excellent property other is somewhat high resistance roller resistance measured is a 3 × 10 ⁶ Ω under N / N environment, practical conductive roller of what range of use is limited is obtained.

Example 18 is different from Example 2 in that lithium perchlorate was used as the ion conductive agent, and the volume resistivity measured on a 2 mm sheet under an N / N environment was 2.5 × 1.
0 ⁷ Ω · cm, roller resistance measured under N / N environment is 3
× 10 ⁶ Ω and a slightly higher resistance.
The characteristics are excellent except that the fluctuation value of the volume resistivity measured on a 2 mm sheet in a / H environment is as large as 1.9 × 10 ^1, and a practically usable conductive roller is obtained although the use range is limited.

Example 19 is different from Example 2 in that the vulcanization system was sulfur vulcanized, and the compression set was 24%.
Other properties that are slightly larger have excellent characteristics, and a practically usable conductive roller can be obtained.

The vulcanization system used in Example 20 is sulfur vulcanization as compared with Example 2, and the compression set is a little as large as 15%. Is obtained.

In Examples 21 and 22, when MgO was used as the acid acceptor in Example 2, as can be seen from a comparison between Example 21 and Example 22, the hardness depends on the amount of MgO added. Is a great difference, but is an excellent property, and a practicable conductive roller can be obtained by strictly controlling the addition amount.

In Example 23, when the addition amount of hydrotalcite as an acid acceptor was increased to 20 parts by mass as compared with Example 2, the hardness was slightly higher at 47 and the compression set was 14%. Other properties that are slightly larger have excellent characteristics, and a practically usable conductive roller can be obtained.

In Comparative Example 1, no sub was added to Example 2, but the rubber kneading and extrusion processability was poor, the hardness was as high as 48, and the surface roughness after polishing was Rz.
Since it was as large as 7.5 μm, the practicality was poor.

In Comparative Example 2, workability was improved and low hardness was obtained by adding dioctyl phthalate as a plasticizer to Comparative Example 1, but the surface roughness after polishing was Rz 10 μm. Therefore, its practicality was inferior.

In Comparative Example 3, dioctyl sebacate as a plasticizer was added to Comparative Example 1 to improve workability and reduce hardness, but the surface roughness after polishing was reduced. Since Rz was as large as 9.5 μm, practicality was poor.

In Comparative Example 4, the workability was improved and the hardness was reduced by adding a sebacic acid-based polyester as a plasticizer to Comparative Example 1, but the surface roughness after polishing was reduced. Was as large as Rz 9.3 μm, which was inferior in practicality.

In Comparative Example 5, the hardness was reduced by using 10 parts by mass of CaCO ₃ as a filler without using a sub and reducing the amount of addition of a vulcanizing agent. The rubber kneading and extrusion processability were very poor, and the compression set was 41%, which was not practical.

In Comparative Example 6, the amount of ethylene oxide was 25
mol% of epichlorohydrin rubber and no ionic conductive agent, but 2m under N / N environment
Volume resistivity measured on m sheet is 6.5 × 10 ⁸ Ω ·
cm, roller resistance measured in N / N environment is 6 × 10 ⁷
The resistance was as high as Ω, and the desired resistance could not be obtained.

In Comparative Example 7, an ion conductive agent was not added to Example 2, but the volume resistivity measured on a 2 mm sheet in an N / N environment was 8.3 × 10 ⁷ Ω · cm.
The roller resistance measured in an N / N environment was as high as 9 × 10 ⁶ Ω, and the desired resistance could not be obtained.

In Comparative Example 8, acrylonitrile butadiene rubber (NBR) was used as the raw material rubber.
Volume resistivity measured with a 2 mm sheet under N environment is 2.1
The roller resistance measured under an environment of × 10 ⁸ Ω · cm and N / N was as high as 2 × 10 ⁷ Ω, and the desired resistance could not be obtained.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

[Table 5]

[0057]

[Table 6]

[0058]

[Table 7]

[0059]

[Table 8]

[0060]

[Table 9]

[0061]

As is apparent from the above description, according to the rubber composition for a conductive roller of the present invention, the hardness is excellent, the workability in production is excellent, the compression set is good, and the surface after polishing is obtained. A conductive rubber material having a small surface roughness and a desired conductivity and containing no lead compound can be obtained.

Accordingly, the conductive roller using the rubber composition for a conductive roller is suitable for a conductive roller such as a charging roller and a developing roller arranged in contact with a photosensitive member in an image forming apparatus such as an electrophotographic apparatus. Can be used for

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 91/00 C08L 91/00 F16C 13/00 F16C 13/00 B G03G 15/08 501 G03G 15/08 501D (72) Inventor Masayuki Hashimoto 1888-2 Kusazaki, Kusazaki-cho, Inashiki-gun, Ibaraki Prefecture Inside Canon Chemical Co., Ltd. Person Naoki Fuui 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (Reference) 2H003 BB11 CC05 2H077 AD06 FA22 FA25 3J103 BA41 EA03 FA03 FA15 FA30 GA02 GA52 GA57 GA58 HA04 HA12 HA20 HA53 4J002 AE052 CH041 CH041 DE196 DE288 EN136 EV347 FD116 FD147 FD208 GM00

Claims (6)

[Claims] 1. A conductive roller having an elastic layer at least on the outer periphery of a conductive shaft, wherein the rubber composition used for the elastic layer is an epichlorohydrin rubber (A component)
A rubber composition for a conductive roller, comprising: as a main raw material, at least a sub-component (B) and an ionic conductive agent (C-component). 2. The (B component) is a three-dimensional crosslinked oil containing no sulfur and chlorine, and the (A component) 100
The rubber composition for a conductive roller according to claim 1, wherein the component (B) is contained in an amount of 10 to 100 parts by mass with respect to parts by mass. 3. The component (A) is an epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer or an epichlorohydrin-ethylene oxide terpolymer alone or a mixture thereof. 3. The rubber composition for a conductive roller according to claim 1, wherein an ethylene oxide copolymerization ratio in the rubber is 36 mol% or more. 4. The (C component) is a quaternary ammonium salt, and the (C component) is added to 100 parts by mass of the (A component).
The rubber composition for a conductive roller according to any one of claims 1 to 3, wherein the component (A) is contained in an amount of 0.5 to 15 parts by mass. 5. The method according to claim 1, wherein 2,4,6-trimercapto-S-triazine (D component) is contained as a vulcanizing agent in addition to the (A component), (B component) and (C component). The rubber composition for a conductive roller according to any one of claims 1 to 4, wherein: 6. Hydrotalcite (E component) as an acid acceptor based on 100 parts by mass of (A component) in addition to (A component), (B component), (C component) and (D component)
The rubber composition for a conductive roller according to claim 5, wherein the rubber composition is contained in an amount of 2 to 15 parts by mass.