JP2003277557A - Rubber parts for preventing paper leaves from being supplied as piled up - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber parts for preventing paper leaves being supplied as piled up which is excellent in abrasion resistance with a certain range of frictional coefficient kept. <P>SOLUTION: The rubber parts for preventing paper leaves being supplied as piled up such as a separating sheet 6 and a separating pad are molded using a rubber composition comprising a rubber component of 100 pts.wt, silicon dioxide of 10-30 pts.wt and a silane coupling agent of 5-30 wt.% relative to the silicone dioxide. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet double feed preventing rubber member, and more specifically, a sheet such as a separation sheet or a separation pad used in a paper feeding mechanism of a copying machine, a printer, a facsimile or the like. Adjust the compounding of the double feed prevention rubber member of
It improves the coefficient of friction and wear resistance.

[0002]

2. Description of the Related Art In a paper feed mechanism, a large number of paper sheets such as PPC paper and OHP film are stored in a tray, and these paper sheets are sent to an image forming mechanism by a paper feed roller. The friction coefficient between the paper feed roller and the paper sheets needs to be relatively large. Specifically, the friction coefficient between the paper sheets and the paper feed roller must be larger than the friction coefficient between the paper sheets. As a result, the sheets are reliably separated one by one and sent to the image forming mechanism, which prevents so-called double feeding.

In this paper feed mechanism, no matter how large the coefficient of friction between the paper sheets and the paper feed roller is, when the number of remaining paper sheets in the tray becomes small (for example, about several sheets), the remaining paper sheets remain. Sometimes all the leaves are sent at once and double feed occurs. This is because the friction coefficient between the tray and the paper sheets is smaller than the friction coefficient between the paper sheets, so that the paper sheets are not reliably separated one by one. In order to prevent double feeding when the number of remaining sheets is small, the friction coefficient between the tray and the sheets needs to be relatively large.

However, if the friction coefficient between the tray and the paper sheets is too large and becomes larger than the friction coefficient between the paper feed roller and the paper sheets, the last paper sheet in the tray cannot be fed and the so-called paper sheet is not fed. The rest will occur. In order to prevent the paper residue, it is necessary that the friction coefficient between the tray and the paper sheets is smaller than the friction coefficient between the paper feed roller and the paper sheets. That is,
In this type of paper feed mechanism, in order to prevent double feed and paper residue at the same time, the friction coefficient μ between the paper feed roller and the paper sheet is
1. The relationship of μ1>μ2> μ3 is required to be established between the friction coefficient μ2 between the tray and the paper sheets and the friction coefficient μ3 between the paper sheets.

For example, when the paper sheets are PPC paper,
μ1 is about 1.5 to 2.5, and μ2 is 0.3 to 0.
It is about 35. Therefore, μ3 needs to be about 0.5 to 1.2. However, since the tray main body is usually made of synthetic resin and the surface of this synthetic resin has a small friction coefficient, it is difficult to set μ3 within an appropriate range only with the tray main body.

Therefore, in order to obtain an appropriate friction coefficient, a sheet multi-feed preventing member such as a separation sheet, a separation pad, a separation roller, etc. may be provided at a position facing the paper feed roller of the tray body. . This type of double feed prevention member is generally molded using a rubber composition, has stable separation performance for paper sheets, and has excellent durability such as ozone resistance and abrasion resistance. Is required.

For example, in JP-A-8-151489,
As a rubber composition having excellent durability, 1 to butadiene rubber is added to 100 parts by weight of a rubber composition comprising 95 to 5 parts by weight of ethylene-propylene-diene three-dimensional copolymer and 5 to 95 parts by weight of acrylic rubber. A rubber composition containing 30 parts by weight has been proposed.

[0008]

However, since the rubber composition of Japanese Patent Laid-Open No. 8-151489 has a low hardness, it has a good friction coefficient as a rubber member for preventing double feeding of paper sheets as described above. There is a problem that you can not.

As described above, unlike the paper feed roller which may have a high friction coefficient, the multi-feed preventing rubber member such as the separation sheet is required to have a friction coefficient within a certain range. Formulation is very important. Usually, in order to control the friction coefficient, the hardness is adjusted to be high. However, when the hardness is increased, there is a problem that the amount of the filler or the like is increased and the abrasion resistance is deteriorated.

The present invention has been made in view of the above problems, and provides a rubber member for preventing double feeding of paper sheets which is excellent in abrasion resistance while maintaining a friction coefficient within a certain range. Is an issue.

[0011]

In order to solve the above problems, the present invention comprises a rubber component containing EPDM rubber as a main component, a silicon oxide and a silane coupling agent, and 100 parts by weight of the rubber component. Silicon oxide is 1
Paper sheets formed by using a rubber composition containing 0 to 30 parts by weight and 5% to 30% by weight of the silane coupling agent with respect to the silicon oxide. To provide a double feed preventing rubber member.

As a result of earnest studies, the present inventor has found that a rubber composition containing EPDM rubber as a main component contains a silane coupling agent in a specified amount together with silicon oxide.
It was found that the hardness can be increased by reducing the amount of the filler (compounding chemical such as calcium carbonate and titanium oxide that is not involved in crosslinking), and the abrasion resistance can be improved. Therefore, abrasion resistance can be improved while having an appropriate friction coefficient as a multi-feed preventing rubber member for paper sheets such as separation sheets and separation pads.

The amount of silicon oxide is set to 10 to 30 parts by weight with respect to 100 parts by weight of the above rubber component. When the amount of silicon oxide is less than 10 parts by weight, the friction coefficient becomes too high, which is good as a double feed preventing rubber member. This is because the performance is not shown. On the other hand, when the amount of silicon oxide is more than 30 parts by weight, the friction coefficient becomes too low and the double feed preventing rubber member does not show good performance and the workability is deteriorated. In addition, it is preferably 15 to 30 parts by weight.

The silane coupling agent has two kinds of functional groups having different reactivities, and the reactive groups can chemically bond the inorganic substance and the organic substance. Therefore, the silane coupling agent reacts with silicon oxide and also bonds with carbon of rubber, whereby the reinforcing property of the double feed preventing member for paper sheets can be increased. The silane coupling agent also reacts with fillers (alumina, titanium oxide, etc.) other than silicon oxide, but since silicon oxide has the same silicon (Si) as the silane coupling agent, it has a particularly good bondability with the silane coupling agent. By using the both in combination, the reinforcing property can be efficiently enhanced. To mix silicon oxide, specifically, it is preferable to mix it as silica (silicon dioxide) and the like, and as the filler containing a large amount of silicon dioxide, kaolin, talc and the like can be mentioned.

The amount of the silane coupling agent is set to 5% by weight to 30% by weight with respect to the silicon oxide because the amount of wear is increased when the amount of the silane coupling agent is less than 5% by weight. On the other hand, if the amount of the silane coupling agent is more than 30% by weight, the rubber hardness becomes high and the friction coefficient becomes low. The content is preferably 10% by weight to 30% by weight.

In the EPDM rubber (ethylene-propylene-diene rubber), the friction coefficient can be easily adjusted by the compounding amount thereof. Further, since the main chain of EPDM is composed of a saturated hydrocarbon and does not contain a double bond in the main chain, even if the EPDM is exposed to a high-concentration ozone atmosphere, an environment such as irradiation with light for a long time, the molecular main chain is unlikely to break. Therefore, the ozone resistance of the double feed preventing rubber member for paper sheets can also be improved.

From the viewpoint of high friction coefficient and high ozone resistance, it is most preferable to use only EPDM as the rubber component. When EPDM and another rubber are blended, the ratio of EPDM to the total rubber is: It is preferably 50% by weight or more, more preferably 80% by weight or more.

1 part by weight of the filler other than the silicon oxide and the silane coupling agent is added to 100 parts by weight of the rubber component.
It is preferably contained in an amount of 5 to 25 parts by weight. this is,
This is because if the amount is less than 15 parts by weight, it is difficult to increase the hardness and it becomes difficult to obtain the necessary friction coefficient. On the other hand, if the amount is more than 25 parts by weight, the abrasion resistance tends to deteriorate. As the filler other than silicon oxide, calcium carbonate, titanium oxide and carbon are preferable. In addition, clay, barium sulphate, magnesium carbonate, metal oxides, inorganic fillers such as mica, graphite, aluminum hydroxide, etc., and one type of compounded chemical that does not affect crosslinking such as metal powder, ceramic powder, glass powder, wood powder, etc. Alternatively, a plurality of types can be used.

The hardness of the rubber member for preventing double feeding of the above-mentioned paper sheets is J
It is preferable that the ISA hardness is in the range of 70 degrees to 90 degrees.
As a result, it is possible to obtain a favorable friction coefficient as the double feed preventing rubber member and to stabilize the separation performance of the paper sheets.

In the above rubber composition, natural rubber (NR) and butadiene rubber (B) are used as rubber components other than EPDM.
R), styrene-butadiene rubber (SBR), isoprene rubber, acrylonitrile-butadiene rubber and other diene rubbers, butyl rubber, BR, isoprene rubber, SBR, chloropropylene rubber (CR), NR, acrylonitrile-butadiene rubber, acrylic rubber, ethylene You may use together 1 type (s) or 2 or more types selected from a propylene rubber (EPR).

Examples of the silane coupling agent include those represented by the following formula. In the formula below, X is an organic reactive group, and examples thereof include an amino group, an epoxy group, a mercapto group, a methacryl group, and a vinyl group. Y is an inorganic reactive group,
In the reactive group represented by the general formula (-OR), R is the same or different saturated alkyl group having 1 to 3 carbon atoms. Note that n is an integer of 1 to 3.

Further, specifically, as the silane coupling agent, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tri (2-methoxyethoxy) silane, vinyltrichlorosilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
Examples thereof include bis (3-triethoxysilylpropyl) tetrasulfene.

As the vulcanizing agent, powdered sulfur is preferable. In addition to sulfur and organic sulfur-containing compounds, peroxides and the like can also be used. Examples of the organic sulfur-containing compound include tetramethylthiuram disulfide and N, N-dithiobismorpholine. Examples of the peroxide include benzoyl peroxide and the like. The addition amount of the vulcanizing agent is 0.5 parts by weight or more and 3 parts by weight or less, preferably 1 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the rubber component.

Further, a vulcanization accelerator may be blended, and inorganic accelerators such as slaked lime, magnesia (MgO) and litharge (PbO) and organic accelerators described below can be used. Examples of organic accelerators include thiazoles such as 2-mercapto benzothiazole, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazolesulfene, and aliphatic primary amines such as n-butylamine, tert-butylamine, and propylamine. And 2-mercapto
Oxidative condensate with benzothiazole, dicyclohexylamine, pyrrolidine, piperidine and other aliphatic secondary amines with 2-mercapto benzothiazole, alicyclic primary amine with 2-mercapto benzothiazole Condensates, sulfenamide compounds such as oxidative condensation products of morpholin-based compounds and 2-mercaptobenzothiazole, and thiuram compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and dipentamethylenethiuram tetrasulfide. , Zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, tellurium diethyldithiocarbamate, etc., dithiocarbamate, trimethylthiourea, N, N ′
-Thiourea such as diethylthiourea, di-ortho-tolylguanidine, 1,3-diphenylguanidine, 1-
A guanidine-based compound such as an ortho-tolyl biguanide or a di-ortho-tolyl guanidine salt of dicatecholborate can be appropriately combined. The addition amount of the vulcanization accelerator is 0.5 parts by weight or more and 5 parts by weight or less, preferably 2 parts by weight or more and 4 parts by weight or less, based on 100 parts by weight of the rubber component.

Further, a vulcanization accelerating aid may be blended, and examples thereof include metal oxides such as zinc white, fatty acids such as stearic acid, oleic acid and cottonseed fatty acid, and other conventionally known vulcanization accelerating aids. To be

If necessary, a plasticizer, a softening agent such as oil, an antioxidant, a wax and the like may be added to the rubber composition.

A known method can be adopted as a method for producing the double feed preventing rubber member of the present invention. For example, the following method can be used. The rubber composition is put into a rubber kneading device such as a twin-screw extruder, an open roll, a Banbury mixer, and a kneader, kneaded, and kneaded for about 5 to 6 minutes while heating at 80 to 90 ° C., and this mixture is mixed. It is set in a mold and press-vulcanized at 165 to 175 ° C. to produce a rubber sheet. After slicing this sheet to a desired thickness, it is further cut into a rectangle of a desired size to form a sheet multi-feed preventing rubber member.

[0028]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a paper feed mechanism using a separation sheet as a double feed prevention rubber member for paper sheets of the present invention.

This paper feed mechanism includes a paper feed roller 2 and a tray 4.
It has and. The tray 4 has a paper feed roller 2 on its upper surface.
A separation sheet 6 is provided on the side. A large number of sheets 8 are stacked and stored on the upper surface of the tray 4. The tray 4 near the paper feed roller 2 is pushed upward by a spring (not shown) that abuts the lower surface of the tray 4, and is pressed toward the paper feed roller 2.

Between the separation sheet 6 and the paper feed roller 2,
The leading end portion 10 of the paper sheet 8 is sandwiched, and the paper feed roller 2
Is rotated in a direction indicated by an arrow R in the figure, so that the paper sheets 8 are fed one by one toward the image forming mechanism.

Separation sheet 6 which is a rubber member for preventing double feeding of paper sheets is formed by using the following rubber composition. EPDM rubber is used alone as the rubber component, and the rubber component is 100
15 parts by weight of silicon oxide is blended with respect to parts by weight, and 10% by weight of a silane coupling agent is blended with respect to silicon oxide. Further, as a filler other than silicon oxide, 15 parts by weight of calcium carbonate, 2 parts by weight of titanium oxide and 1 part by weight of carbon are blended. In addition, sulfur, vulcanization accelerator, zinc oxide, and stearic acid are added.

After kneading the rubber composition having the above composition, it is set in a mold and press-vulcanized at 165 to 175 ° C. to prepare a rubber sheet. After slicing this sheet to a desired thickness, it is further cut into a rectangle having a desired size to obtain a separation sheet 6 which is a rubber member for preventing double feeding of paper sheets.

As described above, the separation sheet 6 is molded using the rubber composition in which the silane coupling agent and the silicon oxide are blended in the specified amounts with respect to the EPDM rubber. Therefore, the hardness can be increased while reducing the amount of the filler to be blended. As a result, the friction coefficient can be adjusted within a certain range, and the abrasion resistance can be improved.

FIG. 2 is a schematic sectional view showing a paper feed mechanism using a separation pad as a double feed preventing rubber member for paper sheets of the present invention. In this paper feeding mechanism, the tray 12 and the paper feeding roller 2 are separated from each other, and a separation pad 16 fixed to the substrate 14 is provided at a position facing the paper feeding roller 2. By rotating the paper feed roller 2 in the direction indicated by the arrow R in the figure, the paper sheets 8 on the tray 12
Are sent to the image forming mechanism one by one.

Further, instead of the separation pad 16, there is also a paper feed mechanism provided with a separation roller, and there is also a paper feed mechanism provided with both a separation pad and a separation sheet. In any case of the above-described separation sheet, separation pad, separation roller, etc., the rubber sheet can be used as the multi-feed preventing rubber member of the present invention.

Further, the surface of the multi-feed preventing rubber member such as the separating sheet, the separating pad, the separating roller and the like may be increased by polishing the surface, and the friction coefficient thereof may be adjusted.

Hereinafter, examples and comparative examples of the double feed preventing rubber member of the present invention will be described in detail. As shown in Table 1 below, for Examples and Comparative Examples, kneaded products having the formulations shown in the tables were prepared, and the kneaded products were press-vulcanized under conditions of 170 ° C. for 20 minutes to obtain 50 mm × 200 mm × 2 mm. After being formed into a sheet, the sheet was sliced into 1.2 mm, and then cut into a rectangle having a width of 10 mm and a length of 60 mm to manufacture a multi-feed preventing rubber member for paper sheets.

[0038]

[Table 1]

The numerical unit of each composition in the table is parts by weight,
The materials used are as follows. EPDM rubber: Sumitomo Chemical's "Esprene 586" Silane coupling agent: Degussa Japan "Si69" Silicon oxide: Nihon Silica "Nipseal VN3" Calcium carbonate: Bihoku powder "BF300" Titanium oxide: Titanium industry "Kronos titanium oxide" KR
380 "Carbon: Tokai Carbon's" SEAST SO "Stearic acid: Nippon Oil &Fat's" Tsubaki "Powder sulfur: Tsurumi Chemical's" powder sulfur "Vulcanization accelerator DM: Dibenzothiazyl disulfide, Ouchi Emerging Chemicals" NOXCELLER DM " Sulfurization accelerator TET: Tetraethyl thiuram disulfide, Ouchi Shinko Kagaku “Noccer TET”

(Examples 1 to 5) As shown in Table 1, EPDM rubber and 10 to 30 parts by weight of silicon oxide per 100 parts by weight of EPDM rubber component are contained in the silicon oxide. On the other hand, a rubber composition containing the above-mentioned silane coupling agent in an amount of 5% by weight to 30% by weight was used to form a double feed preventing rubber member for paper sheets.

(Comparative Examples 1 to 3) In Comparative Example 1, the compounding amount of silicon oxide was smaller than the specified amount. In Comparative Example 2, the compounding amount of silicon oxide was made larger than the specified amount. In Comparative Example 3, the compounding amount of silicon oxide was made larger than the specified amount, and the silane coupling agent was not compounded.

With respect to the double feed preventing rubber members for paper sheets of the above Examples and Comparative Examples, initial friction coefficient, durability (abrasion amount), and paper passing condition were evaluated by the methods described later. In addition, the workability was evaluated as “◯”, and the workability was not so good as “Δ”. Table 1 shows the evaluation results
It shows in the lower column of.

[Measurement of initial friction coefficient] Haydon 14 type friction coefficient measuring machine (trade name "Tribogear" manufactured by Shinto Kagaku Co., Ltd.)
TYPE: HEIDON-14DR ") was prepared, and the initial friction coefficient was measured using a proper bond paper of Canon Inc. as a measuring paper. The measurement condition is that the load is 200 gf
The speed was set to 600 mm / min. An initial friction coefficient of 0.6 or more and 1.1 or less was considered good.

[Paper-passing test] The paper-passing condition was observed with a printer (trade name "LBP470" manufactured by Canon Inc.) equipped with a rubber member for preventing double-feeding of the sheets of Examples and Comparative Examples as a separation pad. It was "○" indicates that the paper passing condition is good,
Those with non-delivery and double feeding were marked with "△", and those with frequent non-delivery and double feeding were marked with "X". In addition, the observation was carried out with the initial 1000 sheets of paper. Further, as the durability test, a 50,000 sheet (50K) sheet passing test was conducted using the above printer. The optimum wear amount was 35 mg or less.

[Measurement of Hardness] JIS A Hardness (JIS
K6253 spring type measuring method) was measured. Example 1
Is 75 °, Example 2 is 70 °, Example 3 is 78 °, Example 4 is 82 °, Example 5 is 87 °, and Comparative Example 1 is 72 °.
Comparative Example 2 was 93 °, and Comparative Example 3 was 86 °.

As shown in Table 1, Examples 1 to 5 are EP
Since DM has a specified amount of silicon oxide and a silane coupling agent, the initial friction coefficient is 0.8 to
It was 1.1, which was an appropriate value for the multi-feed preventing rubber member, and it was confirmed that the paper feeding performance was excellent. Moreover, the abrasion resistance was as small as 15 mg to 30 mg, and the abrasion resistance was excellent. Furthermore, it was excellent in workability.

On the other hand, Comparative Example 1 was not suitable because the amount of wear was as large as 60 mg. In Comparative Example 2, the friction coefficient was low, the paper passing performance was poor, and the processability was also poor. In Comparative Example 3, the wear amount was very large (100 mg), the wear resistance was poor, and the workability and the paper passing performance were not so good.

[0048]

As is apparent from the above description, according to the present invention, the rubber composition containing the EPDM rubber as the main component and the silane coupling agent and silicon oxide in the specified amounts is used. A rubber member for preventing double feeding of paper sheets is molded. Therefore, the hardness can be increased while reducing the amount of the filler to be blended. As a result, the friction coefficient can be adjusted within a certain range, and the abrasion resistance can be improved. Furthermore, it has excellent ozone resistance and can have good durability.

Therefore, when the separation sheet, the separation pad, the separation roller and the like are arranged so as to face the paper feed roller,
The separation performance of paper can be stabilized. Therefore, in a paper feed mechanism such as an inkjet printer, a laser printer, an electrostatic copying machine, a plain paper facsimile machine,
It can be preferably used.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a paper feed mechanism using a separation sheet as a double feed prevention rubber member for paper sheets of the present invention.

FIG. 2 is a schematic cross-sectional view showing a sheet feeding mechanism using a separation pad as a double feed preventing rubber member for paper sheets of the present invention.

[Explanation of symbols]

2 paper feed rollers 4, 12 trays 6 Separation sheet 8 Paper sheets 10 Tip 14 board 16 Separation Pad

Continued front page    F term (reference) 3F343 JD08 JD37                 4F071 AA11 AA12 AA13 AA15X                       AA20X AA21X AA76 AB26                       AC16 AF22 AF28 AH16 BA01                       BB05 BC10                 4J002 AC011 AC021 AC031 AC061                       AC071 AC081 AC091 BB151                       DJ016 EX037 FD016 GM00

Claims (3)

[Claims] 1. A rubber component containing EPDM rubber as a main component, silicon oxide and a silane coupling agent are contained, and 1 part of silicon oxide is contained with respect to 100 parts by weight of the rubber component.
Paper sheets formed by using a rubber composition containing 0 to 30 parts by weight and 5% to 30% by weight of the silane coupling agent with respect to the silicon oxide. Double feed prevention rubber member. 2. The prevention of double feeding of paper sheets according to claim 1, wherein the filler other than the silicon oxide and the silane coupling agent is contained in an amount of 15 to 25 parts by weight with respect to 100 parts by weight of the rubber component. Rubber member. 3. The double feed preventing rubber member for paper sheets according to claim 1 or 2, having a JIS A hardness of 70 to 90 degrees.