JPH10310268A - Rubber composition for paper feed roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a paper feed roller, being high in storage stability and capable of being vulcanized in a short time, and a paper feed roller which is excellent in ozone resistance and will not decrease in friction coefficient even if stocked for a long period. SOLUTION: A rubber composition for a paper feed roller 1 contains ethylene- propylene-diene copolymer rubber as its rubber component, a zinc dithiocarbamate vulcanization promoter as a vulcanization promoter, and a fatty acid vulcanization assistant as a vulcanization assistant, all as essential components, with the copolymer rubber being at least 60 wt.% of the entire rubber components, and with the weight percentages of the zinc dithiocarbamate vulcanization promoter and the fatty acid vulcanization assistant in the entire rubber components being respectively 0.5 to 3 parts by weight and 0.1 to 1.0 parts by weight for 100 parts by weight of the entire rubber components; for 100 parts by weight of the entire rubber components, not more than 10 parts by weight of a filler are contained in the entire composition. The paper feed roller 1 is obtained by vulcanizing the rubber composition.

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 paper feed roller which has high storage stability and can be vulcanized in a short time, and has a low ozone resistance and a low friction coefficient even when stored for a long period of time. And a sheet-feeding / conveying roller without the same.

[0002]

2. Description of the Related Art Image forming apparatuses such as printers, copiers and facsimile machines have a paper feed mechanism in which various rollers and the like are combined. In such a roller, a high paper feeding force and a high abrasion resistance are required in order to obtain a favorable paper feeding state of the recording paper or the like. For this reason, conventionally, natural rubber, urethane rubber, chloroprene rubber, ethylene-propylene-diene copolymer rubber (hereinafter, sometimes referred to as EPDM) has a high friction coefficient and excellent abrasion resistance, such as no solex rubber, and Rubber having excellent mechanical strength is used as the rubber component (Japanese Patent Application Laid-Open No. 7-23779).
7, Japanese Unexamined Patent Application Publication No. 7-293550,
41949 and JP-A-7-263395).

On the other hand, in a copying machine or the like, ozone having a strong oxidizing power is generated in a photosensitive drum portion due to an image forming mechanism.
Therefore, the roller needs to have high ozone resistance.
Recently, EPDM has been suitably used because it satisfies all the above physical properties and is inexpensive.

[0004]

In a rubber composition for a roller containing EPDM, EPDM is a rubber having no double bond in the main chain. Therefore, it is necessary to shorten the vulcanization time and reduce the production cost of the roller. In addition to vulcanization accelerators such as dithiocarbamate and sulfenamide, which have strong accelerating power, vulcanization can be carried out by further using vulcanization aids such as metal oxides and fatty acids. is necessary. However, if the vulcanization time is reduced by simply adding these vulcanization accelerators and vulcanization aids, the vulcanization reaction gradually proceeds during storage of the rubber composition for rollers at room temperature. Thus, there arises a problem that so-called rubber scorch or the like occurs, and the storage stability of the rubber composition for a roller is reduced.

[0005] On the other hand, fillers, plasticizers, and the like are further added to the rubber composition, if necessary, for the purpose of imparting reinforcing properties and the like. In order to balance the hardness and flexibility of the obtained roller and to increase the initial coefficient of friction, a small amount of filler is usually blended in the rubber composition for rollers. However, if the compounding amount of the filler is too small, the vulcanization accelerator, the vulcanization aid and the plasticizer contained in the roller are precipitated from the roller surface during storage, and the friction coefficient of the roller gradually decreases. The problem arises.

[0006] Therefore, an object to be solved by the present invention is to provide a rubber composition for a paper feed roller which has high storage stability and can be vulcanized in a short time, and has excellent ozone resistance and can be stored for a long period of time. An object of the present invention is to provide a sheet feeding / conveying roller without a decrease in friction coefficient.

[0007]

Means for Solving the Problems The present inventors have conceived that in order to achieve the above objects, it is necessary to consider the types and amounts of vulcanization accelerators and vulcanization aids, and these are considered. As a result of diligent studies on, as a result of selecting a zinc dithiocarbamate-based vulcanization accelerator as a vulcanization accelerator, and selecting a fatty acid-based vulcanization aid as a vulcanization aid, and setting the amounts thereof within a specific range, the rubber composition With the knowledge that vulcanization in a short time can be realized without lowering the storage stability of the product and that the obtained roller does not show a decrease in the coefficient of friction even after long-term storage, the present invention has been reached. .

That is, the rubber composition for a paper feed roller of the present invention comprises an ethylene-propylene-diene copolymer rubber as a rubber component, a zinc dithiocarbamate-based vulcanization accelerator as a vulcanization accelerator, and a vulcanization aid. Wherein the copolymer rubber is at least 60% by weight of the whole rubber component, and the zinc dithiocarbamate-based vulcanization accelerator and the fatty acid-based vulcanization are based on the whole rubber component. The weight ratio of the auxiliaries is 1
0.5 to 3 parts by weight of a zinc dithiocarbamate vulcanization accelerator and 0.1 to
1.0 part by weight, and the filler contains not more than 10 parts by weight based on 100 parts by weight of the whole rubber component in the whole composition.

The paper feed roller of the present invention is obtained by vulcanizing the above rubber composition.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition for a paper feeding / conveying roller of the present invention contains a rubber component containing EPDM, a zinc dithiocarbamate-based vulcanization accelerator, and a fatty acid-based vulcanization aid as essential components. , A composition that may further comprise a filler. Hereinafter, each component of the rubber composition for the paper feeding and conveying roller will be described in detail. [Rubber Component] The rubber component used in the rubber composition for the paper feeding and conveying roller of the present invention contains EPDM as a main component. E
The PDM has an effect of imparting excellent ozone resistance to a paper feed roller obtained by vulcanizing the rubber composition, and preventing a friction coefficient from being lowered even after long-term storage. EPDM should be mixed in at least 6 parts of the total rubber component.
0% by weight, preferably 70% by weight or more, more preferably 80% by weight or more. If the blending ratio of EPDM is less than 60% by weight, ozone resistance is reduced, and the coefficient of friction is reduced during storage.

The rubber component may contain a rubber component other than EPDM as required. As such other rubber components, for example, natural rubber, ethylene-propylene rubber (EPM), styrene-butadiene rubber (SB)
R), butyl rubber (IIR), acrylonitrile-butadiene rubber (NBR), chlorosulfonated polyethylene, silicone rubber, urethane rubber, and silicone-ethylene propylene mixed rubber. Among them, acrylonitrile-butadiene rubber (NBR) is preferable as the other rubber component. [Zinc dithiocarbamate-based vulcanization accelerator] The rubber composition for a paper feed roller of the present invention contains a zinc dithiocarbamate-based vulcanization accelerator as an essential component as a vulcanization accelerator. The vulcanization accelerating power of the zinc dithiocarbamate vulcanization accelerator is very strong. For this reason, EPDM which does not have a double bond in the main chain and is difficult to vulcanize with a normal vulcanization accelerator can be vulcanized in a short time.

Examples of the zinc dithiocarbamate-based vulcanization accelerator include, for example, zinc dimethyldithiocarbamate (Z
nMDC), zinc diethyldithiocarbamate (ZnE
DC), zinc di-n-butyldithiocarbamate (Zn
BDC), zinc pentamethylenedithiocarbamate (Z
nPDC), zinc dibenzyldithiocarbamate (Zn
DBDC) and zinc ethylphenyldithiocarbamate (ZnEPDC). Zinc dithiocarbamate-based vulcanization accelerator is one of these
Species may be used, or two or more kinds may be used. Among them,
Examples of the zinc dithiocarbamate-based vulcanization accelerator include di-n
-Zinc butyldithiocarbamate is preferred.

The mixing ratio of the zinc dithiocarbamate vulcanization accelerator in the rubber composition for a roller of the present invention is 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, per 100 parts by weight of the whole rubber component. It is 3 parts by weight, more preferably 1-2 parts by weight. If the compounding ratio of the zinc dithiocarbamate-based vulcanization accelerator is less than 0.5 part by weight with respect to 100 parts by weight of the entire rubber component, the vulcanization time becomes longer, and the cost of manufacturing the paper feed roller increases. . On the other hand, the mixing ratio of the zinc dithiocarbamate-based vulcanization accelerator is 100% for the entire rubber component.
If the amount exceeds 3 parts by weight with respect to parts by weight, the vulcanization reaction gradually proceeds during storage of the rubber composition for a roller at room temperature, so-called rubber scorch or the like occurs, and the rubber composition for a roller The storage stability is reduced, and the fluidity of the rubber component is reduced in the mold during vulcanization, so that a normal paper feed roller cannot be obtained.

The vulcanization accelerator may be, in addition to the zinc dithiocarbamate-based vulcanization accelerator, suitably a dithiocarbamic acid or other metal vulcanization accelerator or a general-purpose vulcanization accelerator (hereinafter referred to as "dithiocarbamic acid or other metal vulcanization accelerator"). Accelerators, general-purpose vulcanization accelerators, etc. "may be referred to as" other vulcanization accelerators. ") The solubility of the rubber component and the vulcanization accelerator is balanced, and the vulcanization rate is adjusted. It is preferable because it can be performed.

Examples of dithiocarbamic acid and other metal vulcanization accelerators include dimethyldithiocarbamate, diethyldithiocarbamate, and di-n, of metals such as tellurium, selenium, lead, cadmium, copper, bismuth, iron and nickel. -Butyldithiocarbamate, pentamethylenedithiocarbamate, ethylphenyldithiocarbamate and the like. Dithiocarbamic acid and other metal vulcanization accelerators are one of these
Species may be used, or two or more kinds may be used.

As general-purpose vulcanization accelerators, for example, tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), dipentamethylenethiuram tetrasulfide Thiuram-based vulcanization accelerators such as sulfide (DPTT); 2-mercaptobenzothiazole (MB
T), dibenzothiazyl disulfide (MBTS), 2
-Mercaptobenzothiazole zinc salt (ZnMBT),
2-mercaptobenzothiazole sodium salt (NaM
BT), cyclohexylamine salt of 2-mercaptobenzothiazole (CMBT), 2- (2'4-denitrophenylthio) benzothiazole (DPBT) and other thiazole vulcanization accelerators; N-cyclohexyl-2-benzothiazole Sulfenamide (CBS), Nt-butyl-2-benzothiazolesulfenamide (BBS),
N-oxyethylene-2-benzothiazolesulfenamide (OBS), N, N'-diisopropyl-2-benzothiazolesulfenamide (DPBS), N,
Examples thereof include sulfenamide-based vulcanization accelerators such as N'-dicyclohexyl-2-benzothiazolesulfenamide. The general-purpose vulcanization accelerator may be any one of these, or may be two or more. Among them, as the general-purpose vulcanization accelerator, at least one selected from tellurium diethyldithiocarbamate, N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and tetramethylthiuram disulfide (TMTD) is preferable. It is more preferable to use them in combination.

The compounding ratio of the other vulcanization accelerator in the rubber composition for the paper feeding and conveying roller of the present invention is 6 parts by weight or less, preferably 1 to 5 parts by weight, per 100 parts by weight of the whole rubber component. Parts, more preferably 2 to 4 parts by weight. When the amount of the other vulcanization accelerator exceeds 6 parts by weight, the other vulcanization accelerator blooms, and the friction coefficient of the sheet feeding / conveying roller tends to decrease. [Fatty Acid Vulcanization Aid] The rubber composition for the paper feed conveyance roller of the present invention contains a fatty acid vulcanization aid as an essential component as a vulcanization aid. As described above, EPDM is difficult to vulcanize. Therefore, by using a zinc dithiocarbamate-based vulcanization accelerator having a strong vulcanization accelerating power and using a fatty acid-based vulcanization aid together, EPDM can be vulcanized in a shorter time. Can be vulcanized.

Examples of the fatty acid-based vulcanization aid include stearic acid, oleic acid, palmitic acid, lauric acid,
Behenic acid and the like can be mentioned. The fatty acid-based vulcanization aid may be any one of these, or may be two or more. The compounding ratio of the fatty acid-based vulcanization aid in the rubber composition for a roller of the present invention is 0.1 to 1.0 part by weight, preferably 0.1 to 0 part by weight, per 100 parts by weight of the whole rubber component. 0.7 parts by weight, more preferably 0.2 to
0.5 parts by weight. The compounding ratio of the fatty acid-based vulcanization aid is
If the amount is less than 0.1 part by weight with respect to 100 parts by weight of the whole rubber component, the vulcanization time becomes longer, and the cost of manufacturing the paper feed roller increases. On the other hand, when the compounding ratio of the fatty acid-based vulcanization aid exceeds 1.0 part by weight with respect to 100 parts by weight of the entire rubber component, the friction coefficient of the paper feed roller obtained by vulcanizing the rubber composition for a roller is increased. Greatly decreases during storage, and the paper feeding force decreases.

If the vulcanization aid contains a metal oxide-based vulcanization aid such as zinc oxide or magnesium oxide in addition to the fatty acid-based vulcanization aid, the vulcanization accelerator can be activated. Therefore, it is preferable. The compounding ratio of the metal oxide-based vulcanization aid in the rubber composition for a roller of the present invention is 10 parts by weight or less, preferably 3 to 7 parts by weight, per 100 parts by weight of the whole rubber component.
Parts by weight, more preferably 4 to 6 parts by weight. If the amount of the metal oxide-based vulcanization aid exceeds 10 parts by weight, the metal oxide-based vulcanization aid will bloom and the coefficient of friction of the sheet feeding / conveying roller tends to decrease. [Filler and Other Ingredients] The rubber composition for the paper feeding and conveying roller of the present invention may contain a filler. The filler is
Usually, it is used to improve the reinforcing property. The compounding ratio balances the hardness and the flexibility of the paper feed roller obtained by vulcanization, and furthermore, in order to increase the initial friction coefficient, 100 parts by weight of the whole rubber component in the whole composition. 10 parts by weight or less, and may be 0 parts by weight. When the amount of the filler exceeds 10 parts by weight based on 100 parts by weight of the whole rubber component, the hardness of the paper feed roller obtained by vulcanization increases, and the initial coefficient of friction decreases.

Examples of the filler include powders of silica, carbon black, clay, talc, calcium carbonate, titanium oxide, dibasic phosphite (DLP), basic magnesium carbonate, alumina and the like. it can.
The filler may be any one of these, and
Two or more types may be used. In addition to the components described in detail above, the rubber composition for a paper feed roller of the present invention may further include, as necessary, for example, a paraffinic, naphthenic, aromatic or other mineral oil-based softener, or dioctyl. Phthalate (DOP), dibutyl phthalate (DBP), dioctyl sepate (DOS), dioctyl adipate (DO)
Additives such as a plasticizer such as A); sulfur; a foaming agent; an antioxidant; and a wax. The mixing ratio of these additives is not particularly limited, and a necessary amount can be appropriately used.

As the method for producing the rubber composition for the paper feed / conveyance roller, a known method can be adopted. For example, each of the above-mentioned components can be mixed with a rubber kneading device such as an open roll or a Banbury mixer to obtain a rubber composition. ~ 130 ° C, 10
It is obtained by kneading for 60 minutes. [Sheet Conveying Roller] The sheet conveying roller of the present invention is obtained by vulcanizing the above-described rubber composition for the sheet conveying roller. A known method can be employed as a method of manufacturing the paper feed conveyance roller. For example, using an injection molding machine, the rubber composition for the paper feed conveyance roller is formed into a shape of the paper feed conveyance roller while being vulcanized. And the rubber composition for the paper feeding and transporting roller is transferred to, molded by, injection molding, vulcanizing can, electric press, etc.
There is a method of forming and vulcanizing at 10 ° C. for 10 to 120 minutes at a pressure of 3 to 60 kg / cm ² .

The shape of the paper feeding and conveying roller is not particularly limited as long as it is cylindrical or columnar. FIG. 1 shows a schematic diagram in which a sheet feeding roller is used as a sheet feeding roller of a copying machine. A shaft 2 is fitted in the center hole of the paper feed roller 1, and a pad 3 is provided to face the paper feed roller 1. When the shaft 2 is rotated around the central axis in the direction of the arrow,
The paper feed roller 1 also rotates in the same direction about the same central axis as the center of rotation, so that the paper 4 near the paper feed roller 1 is entangled and passes through the gap between the paper feed roller 1 and the pad 3. That is, the paper 4 is supplied into the copy machine.

Next, FIG. 2 is a schematic diagram in which the sheet feeding and conveying rollers are used as the conveying rollers of a copying machine. In the same manner as described above, two transport rollers 5 with the shafts 2 mounted thereon are prepared and opposed to each other. When the respective shafts 2 are rotated in opposite directions, the paper 4 near the transport rollers 5 is entangled. The paper passes through the gap between the opposing transport rollers 5 and 5. The paper feeding and conveying roller of the present invention can be easily mass-produced because of its excellent molding workability, and can be used for various devices having a mechanism for conveying paper. For example, when used for a paper feeding roller, a conveying roller, a paper discharging roller, and the like of an image forming apparatus such as a laser beam printer, an electrostatic copying machine (copying machine), and a plain paper facsimile machine, the properties of ozone resistance are sufficiently high. Be demonstrated. Also, even if the paper feed / conveyance rollers are stored for a long period of time, the vulcanization accelerator, vulcanization aid, and plasticizer contained in the paper feed / conveyance rollers precipitate out from the roller surface during storage, and the paper Does not occur.

[0024]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to the following Examples. (Example 1) A rubber component of each amount (parts by weight) shown in Table 1,
Filler, zinc white, stearic acid, zinc di-n-butyldithiocarbamate (Noxeller BZ), 2 parts by weight of softener (Diana Process Oil PW-90, manufactured by Idemitsu Kosan), N-cyclohexyl-2-benzothiazole sulf 2 parts by weight of phenamide (Ouchi Shinko Chemical, Noxeller CZ), 1 part by weight of tetraethylthiuram disulfide (Ouchi Shinko Chemical, Noxeller TET), tellurium diethyldithiocarbamate (Ouchi Shinko Chemical, Noxeller TTT)
E) 0.5 part by weight and 3 parts by weight of sulfur (trade name: powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.) were prepared, and the above components were kneaded at 110 ° C. for 15 minutes using a Banbury mixer.
A rubber composition (1) was obtained.

The obtained rubber composition (1) was subjected to transfer molding using a press mold, and the surface was polished to produce a rubber roller (1) having an outer diameter of 30 mm, an inner diameter of 20 mm, and a width of 20 mm. The molding conditions were as follows: molding temperature: 160 ° C .; molding time: JIS K6300, 8.
According to the method described in 3.5, t of the rubber composition (1)
_c (90) was _calculated and set to twice this t _c (90).

Each friction coefficient of the obtained rubber roller (1),
The vulcanization time, storage stability, hardness and ozone resistance were evaluated by the following evaluation methods, and the results and the overall judgment of these results are shown in Table 1. [Evaluation method] Coefficient of friction was measured using the apparatus shown in FIG. Temperature 23 ℃, humidity 5
Under an atmosphere of 0%, the A4 size paper 4 is set between the transport roller 5 and the Teflon plate 6 and 500 gf
Vertical load (W) is applied, and the peripheral speed is 50 mm / sec (a).
And the measured value (F, unit: gf) of the load cell 7 at that time was determined, and the friction coefficient (μ) was determined by the following equation.

Coefficient of friction (μ) = F / 500 The initial coefficient of friction (μ ₀ ) is a value measured after a rubber roller is manufactured and left for one day in an atmosphere of a temperature of 23 ° C. and a humidity of 50%. Coefficient of friction during storage, μ ₃₀ (coefficient of friction after standing for 30 days), μ ₆₀ (coefficient of friction after standing for 60 days), μ
₁₈₀ (coefficient of friction after standing for 180 days) were 30 and 6 in an atmosphere of a temperature of 23 ° C. and a humidity of 50%, respectively.
0 and values measured after standing for 180 days. Vulcanization time When the above t _c (90) was within 10 minutes, it was evaluated as ○, and when it exceeded 10 minutes, it was evaluated as ×. After the storage-stable rubber composition was left at 30 ° C. for 14 days, transfer molding was performed, and the molding state was observed. Those without rubber burns were rated as 、, and those with rubber burns were rated as △. Hardness (Hs) was measured according to JIS A. The rubber roller was allowed to stand for 12 hours in an atmosphere having an ozone resistance of 40 ° C. and an ozone concentration of 100 pphm, and the surface condition of the rubber was examined.
も の indicates a good surface condition, Δ indicates a slightly good surface condition, and × indicates a poor surface condition. All friction coefficients (μ ₀ , μ ₃₀ , μ ₆₀ , μ ₁₈₀ ) were 2.0 or more, μ ₁₈₀ -μ ₀ was 0.2 or less, and the vulcanization time and storage stability were Certain items were evaluated as comprehensive judgment ○. The results other than the comprehensive judgment ○ were evaluated as the comprehensive judgment ×. (Examples 2 to 8, Comparative Examples 1 to 6) For rubber components, fillers, zinc white, stearic acid and zinc di-n-butyldithiocarbamate (Noxeller BZ), the amounts shown in Tables 1 and 2, respectively. (Parts by weight), 2 parts by weight of a softening agent, 2 parts by weight of N-cyclohexyl-2-benzothiazolesulfenamide (Noxeller CZ), and tetraethylthiuram disulfide (Noxerar TET)
1 part by weight, 0.5 parts by weight of tellurium diethyldithiocarbamate (Noxeller TTTE) and 3 parts by weight of sulfur were prepared and kneaded in the same manner as in Example 1 to obtain a rubber composition (2) to
(8) and Comparative rubber compositions (1) to (6) were obtained.

The obtained rubber composition was molded in the same manner as in Example 1 to produce rubber rollers (2) to (8) and comparative rubber rollers (1) to (6). The friction coefficient, vulcanization time, storage stability, hardness and ozone resistance of the obtained rubber roller were evaluated, and the results and the comprehensive judgment of these results are shown in Tables 1 and 2.

[0029]

[Table 1]

[0030]

[Table 2]

* 1 ESPRENE 60 manufactured by Sumitomo Chemical Co., Ltd.
0F EPDM: extending oil = 50: 50 (weight ratio). The values shown in the table do not include the extension oil. * 2 Nipol 1052J manufactured by Zeon Corporation. * 3 Asahi Carbon FEF Asahi # 60. * 4 Nipsil L300 made by Nippon Silica.

* 5 Company: manufactured by Mitsui Kinzoku Mining Co., Ltd.
Two types of zinc oxide. * 6 Company: Nippon Oil & Fat Product name: Stearic acid
Paulownia. * 7 Nouchira BZ manufactured by Ouchi Shinko Chemical. <Evaluation Results> In Examples 1 to 8, all of the rubber compositions have high storage stability and can be vulcanized in a short time.
Further, the paper feed roller obtained by vulcanizing the rubber composition is excellent in ozone resistance, and does not lower the friction coefficient even when stored for a long period of time.

In Comparative Example 1, since stearic acid was not added, the vulcanization time was prolonged, and the cost of manufacturing the paper feed roller was increased. Further, in Comparative Example 2, since the blending amount of stearic acid was too large, the friction coefficient of the paper feed roller obtained by vulcanizing the rubber composition was significantly reduced during storage, and the paper feeding force was reduced. In Comparative Example 3, since zinc di-n-butyldithiocarbamate was not blended,
The vulcanization time is prolonged, and the cost of manufacturing the feed roller is increased. Further, in Comparative Example 4, since the amount of zinc di-n-butyldithiocarbamate was too large, the vulcanization reaction gradually progressed during storage of the rubber composition at room temperature, and so-called rubber burning and the like occurred. As a result, the storage stability of the rubber composition for rollers is slightly reduced.

In Comparative Example 5, since the blending amount of EPDM is too small, the obtained paper feed roller has reduced ozone resistance and reduced friction coefficient during storage. In Comparative Example 6, since the amount of the filler was too large, the hardness of the sheet feed roller obtained by vulcanization was high, and the initial coefficient of friction was low.

[0035]

The vulcanization reaction of the rubber composition of the present invention for a paper feeding and conveying roller does not progress gradually during storage at room temperature, the storage stability is high, and the rubber composition is used in a short time. Can be vulcanized. Further, the paper feed transport roller of the present invention has excellent ozone resistance, and even when stored for a long period of time, the vulcanization accelerator, vulcanization aid, and plasticizer contained in the roller precipitate from the roller surface during storage. And there is no reduction in the coefficient of friction.

[Brief description of the drawings]

FIG. 1 is a schematic diagram in which a sheet feed roller of the present invention is used as a sheet feed roller of a copying machine.

FIG. 2 is a schematic diagram in which a paper feed conveyance roller of the present invention is used as a conveyance roller of a copying machine.

FIG. 3 is a schematic diagram illustrating a method for measuring a friction coefficient of a sheet feeding / conveying roller according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed roller 2 shaft 3 pad 4 paper 5 transport roller 6 Teflon plate 7 load cell

Claims (2)

[Claims] An essential component of an ethylene-propylene-diene copolymer rubber as a rubber component, a zinc dithiocarbamate-based vulcanization accelerator as a vulcanization accelerator, and a fatty acid-based vulcanization aid as a vulcanization aid. The copolymer rubber is at least 60% by weight of the whole rubber component, and the weight ratio of the zinc dithiocarbamate-based vulcanization accelerator and the fatty acid-based vulcanization aid to the whole rubber component is 100 parts by weight of the whole rubber component. On the other hand, 0.5 to 3 parts by weight of a zinc dithiocarbamate-based vulcanization accelerator and 0.1 to 1.0 part by weight of a fatty acid-based vulcanization aid, and 100% of the rubber component in the whole composition A rubber composition for a paper-feeding / conveying roller, containing 10 parts by weight or less of a filler relative to parts by weight. 2. A paper feed roller formed by vulcanizing the rubber composition according to claim 1.