JP4593389B2 - Paper feed roller - Google Patents

Description

  The present invention relates to a rubber roller for paper feeding, and more particularly to a rubber roller used for a paper feeding mechanism in an ink jet printer, a laser printer, an electrostatic copying machine, a plain paper facsimile machine, an automatic deposit payment machine (ATM) and the like. It is.

  In OA equipment such as inkjet printers, laser printers, electrostatic copying machines, facsimile machines, and automatic deposit payment machines (ATMs), the paper feed mechanism that transports paper, films, etc. includes natural rubber, urethane rubber, and EPDM. A rubber roller for paper feeding made of rubber such as rubber, polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber or an elastomer composition is used.

  In recent years, the number of office automation equipment for personal use has increased, and various types of paper have been passed. It is required to ensure wearability and a high friction coefficient. Therefore, it has been proposed to obtain a high friction coefficient by reducing the hardness of the rubber roller. However, when the hardness of the rubber roller is lowered, there is a problem that the wear resistance is deteriorated. In addition, when a large amount of oil as a softening agent is added to reduce the hardness, there is a problem that the oil added in a large amount bleeds and precipitates on the surface, and a roller mark remains on the printed matter.

  In order to solve the above problem, in Japanese Patent Laid-Open No. 2001-335180 (Patent Document 1), as shown in FIG. 4, a sheet feeding member comprising a core body 2 and an annular elastic body 3 attached to the outer peripheral surface thereof. 1, by providing a plurality of convex portions 4 on the inner peripheral surface of the annular elastic body 3, the rubber elasticity of the annular elastic body 3 is increased, and the paper feeding member 1 that can increase the friction coefficient of the surface of the paper feeding member is provided. Proposed.

  In addition, in Japanese Patent Application Laid-Open No. 2005-035732 (Patent Document 2), the present applicant uses the inner peripheral surface 5a of the rubber roller 5 as a knurled surface as shown in FIG. 5, and sets the surface roughness Rmax of the inner peripheral surface. By setting the Shore A hardness in the range of 0.05 mm to 2.0 mm and the Shore A hardness in accordance with JIS K6253 to 20 to 60, a rubber roller having a high friction coefficient is proposed.

  However, the paper feeding member of Patent Document 1 and the rubber roller of Patent Document 2 are both made up of a single layer of solid rubber. With such a paper feed roller made up of a single layer of solid rubber, friction increases when the number of sheets to be passed increases. There is a possibility that so-called non-feeding may occur because the coefficient decreases and the paper cannot be fed.

  Further, in a paper feed roller composed of a single layer of solid rubber, unpleasant unusual noise called “squeal” such as cue / cue / shoes / shoes often occurs when paper is passed. The occurrence of squeal when passing paper causes the roller to vibrate when the paper rubs against the roller surface, and the vibration causes the shaft core, the bearing member, the housing, etc. of the paper feeding device to resonate and resonate. Therefore, in order to reduce the noise, it is necessary to absorb the vibration of the paper feed roller inside the roller so that the vibration is not transmitted to the shaft core. On the other hand, a gap is formed in the paper feeding member of Patent Document 1 and the rubber roller of Patent Document 2 by a convex portion or a knurled surface. This gap is formed in the roller in contact with the shaft core. Since it is a peripheral surface, it cannot be said that vibration absorption is sufficient, and there is a problem that vibrations are transmitted to the shaft core, resulting in squealing.

JP 2001-335180 A JP 2005-035732 A

  The present invention has been made in view of the above problems, and has a high coefficient of friction and wear resistance, and the decrease in the coefficient of friction is small even when the number of sheets to be passed increases. An object of the present invention is to provide a paper feed roller that can greatly reduce the occurrence of abnormal noise.

In order to solve the above-mentioned problem, the present invention is a paper feed roller that is used with a shaft core attached to a hollow portion of a rubber roller,
The rubber roller is composed of two or more laminated rubber layers, and a knurled groove is provided on the outer circumferential surface of any one of the rubber layers other than the outermost circumferential layer, and the inner circumferential surface of the knurled groove and the outer circumferential rubber layer. The value of V1 / V2 is 0.3 or more and 0.7 or less, where V1 is the total volume of the voids formed by the above and V2 is the total volume of the laminated rubber layers. Offering a roller.

  As described above, when the rubber roller is composed of two or more laminated rubber layers and a knurled groove is provided on the outer circumferential surface of any one of the rubber layers other than the outermost circumferential layer, the knurled groove and the outer circumferential rubber layer are provided. The gap formed by the inner peripheral surface of the sheet can serve as a cushion that absorbs vibrations and shocks generated during paper feeding. Therefore, the hardness of the entire roller can be reduced, the contact area between the paper feed roller and the paper can be increased, and the friction coefficient of the entire rubber roller can be increased. Further, even if the number of sheets to be passed increases, the decrease in the friction coefficient can be reduced.

  In particular, the rubber roller is composed of two or more laminated rubber layers, and the knurled groove is provided not on the inner peripheral surface in contact with the shaft core but on the outer peripheral surface of any one rubber layer other than the outermost peripheral layer. Vibrations and shocks generated during paper feeding can be absorbed by the gap inside the roller away from the shaft core. Therefore, since the vibration and impact generated in the paper feed roller are not easily transmitted to the shaft core, the occurrence of squeal can be greatly reduced.

In the paper feed roller of the present invention, V1 / when V1 is the total volume of voids formed by the knurled grooves and the inner peripheral surface of the outer peripheral rubber layer, and V2 is the total volume of the laminated rubber layers. The value of V2 is set to 0.3 or more and 0.7 or less. If V2 is less than 0.3, the gap formed by the knurled groove and the inner peripheral surface of the rubber layer on the outer peripheral side becomes narrower. This is because the performance deteriorates, the necessary friction coefficient as the paper feed roller and sufficient vibration absorption cannot be obtained, and the occurrence of squeal cannot be reduced. On the other hand, if the ratio exceeds 0.7, the outer diameter of the rubber roller increases and wear resistance deteriorates.
More preferably, the value of V1 / V2 is 0.4 or more and 0.6 or less.

The shape of the knurled groove may be appropriate, but it is preferable that the knurled groove is continuously provided in the axial direction and is provided at a constant pitch in the circumferential direction. It can set suitably so that it may become 0.7 or less.
The rubber layer provided with knurled grooves on the outer peripheral surface formed a rubber composition composed of a rubber material, a vulcanizing agent, and various compounding agents blended as necessary, and formed desired irregularities (knurled pattern) on the inner surface. It can be obtained by vulcanization molding using a mold.

Further, in the paper feed roller of the present invention, an outer layer is a rubber layer on the outer peripheral side from the rubber layer provided with the knurled groove, and an inner layer is a rubber layer provided with the knurled groove and a rubber layer on the inner peripheral side from the rubber layer. The Shore A hardness according to JIS K6253 is preferably 20 or more and 60 or less for the outer layer and 15 or less for the inner layer. The lower limit of the inner layer is “0” or more, but this “0” is in a state where the hardness is too low but the needle does not move on the hardness meter and indicates “0”.
As described above, by setting the Shore A hardness of the outer layer to 20 or more and 60 or less, it is possible to obtain a high coefficient of friction and maintain wear resistance. If the range is less than 20, the wear resistance of the roller is likely to be reduced, and if it is greater than 60, the friction coefficient is lowered and the roller performance may not be sufficiently exhibited. It depends on.
The Shore A hardness of the outer layer described above is a value measured according to JIS K6253 for a single rubber layer.

In addition, as described above, the inner layer is softer than the outer layer, and the Shore A hardness of the inner layer is 0 or more and 15 or less, so that a higher friction coefficient can be obtained for the entire roller, and the vibration absorption is increased to reduce noise. Can be made.
The Shore A hardness of the inner layer is a value measured according to JIS K6253 for the rubber layer alone.
The outer layer of the paper feed roller of the present invention is preferably 1 to 2 layers, and the inner layer is also preferably 1 to 2 layers.

The rubber layer constituting the paper feed roller of the present invention is obtained by crosslinking a composition containing rubber as a main component. Examples of the rubber used include natural rubber, ethylene-propylene-diene copolymer rubber (EPDM), polynorbornene rubber, butadiene rubber, butyl rubber, isoprene rubber, styrene butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, acrylic rubber, Examples include chlorosulfonated polyethylene. In particular, most of the main chain consists of saturated hydrocarbons and does not contain much double bonds in the main chain, so molecular main chain cleavage is unlikely to occur even when exposed to high-concentration ozone atmosphere, light irradiation, or other environments for a long time. For this reason, EPDM rubber is preferably used for the rubber component of the outer layer. The EPDM rubber includes a non-oil-extended EPDM rubber composed only of a rubber component and an oil-extended EPDM rubber containing a confidential oil together with the rubber component of the EPDM. The type can also be used.
As the rubber component of the inner layer, butyl rubber having low rebound resilience and excellent vibration damping is also preferably used.

  The rubber layer constituting the paper feed roller of the present invention is obtained by crosslinking the composition. The crosslinking form is not particularly limited, and sulfur crosslinking, metal salt crosslinking, peroxide crosslinking, resin crosslinking, electron beam crosslinking, and the like can be applied. In general, sulfur crosslinking is performed, but a vulcanization accelerator may be used in combination with the sulfur crosslinking. Depending on the use conditions, blooming may occur on the roller surface due to sulfur crosslinking, and in this case, resin crosslinking may be used.

Moreover, a softener, a filler, a reinforcing agent, etc. are suitably mix | blended with the said composition as needed. Examples of the softening agent to be blended include oils such as paraffinic mineral oils, naphthenic mineral oils, aromatic mineral oils, synthetic oils composed of hydrocarbon oligomers, dioctyl phthalate, dibutyl phthalate, dioctyl sepagate, dioctyl adipate. And the like. Therefore, by increasing the amount of the softening agent added to the composition of the inner layer over the outer layer, an inner rubber layer having a lower hardness than the outer layer can be obtained.
Examples of the filler to be blended include silica and zinc oxide. Moreover, as a reinforcement agent mix | blended, carbon black is mentioned, for example.

  When obtaining a roller-shaped molded product of the crosslinked rubber composition, first, the respective raw materials are kneaded. Even if the kneaded product is crosslinked before or after the molding, the working time is shortened. Alternatively, the kneaded product may be formed simultaneously. When a roller-like rubber layer is produced by crosslinking simultaneously with molding of the kneaded product, a mold having a desired tube shape is heated, and the kneaded product is filled into the heated mold and compression molded. (Press vulcanization).

The laminated rubber layers in the paper feed roller of the present invention are formed separately, and the inner peripheral rubber layer is press-fitted into the hollow portion of the outer rubber layer, or the inner peripheral rubber layer A rubber layer on the outer peripheral side may be externally fitted to the rubber layer and integrated.
The outer peripheral rubber layer in contact with the rubber layer provided with the knurled groove may be externally fitted to the rubber layer provided with the knurled groove via an adhesive and integrated with the adhesive.

  The paper feed roller according to the present invention effectively absorbs vibration and impact generated on the roller surface during the passage of the paper inside the roller and makes it difficult to transmit the vibration and impact to the shaft core. Can do. On the other hand, when a plurality of sheets enter the retard roller, the torque limiter may balance and stop, and in this state, stick slip occurs between the sheet and the retard roller, and noise often occurs. . Therefore, when the paper feed roller is used as a retard roller, not only the paper feed performance is improved by a high friction coefficient but also the noise can be reduced.

  As described above, according to the present invention, the rubber roller is composed of two or more laminated rubber layers, and the knurled groove is provided on the outer circumferential surface of any one rubber layer other than the outermost circumferential layer. The value of V1 / V2 is 0.3 or more and 0.7 when the total volume of voids formed by the inner peripheral surface of the outer peripheral rubber layer is V1, and the total volume of the laminated rubber layers is V2. By making the following, wear resistance and a high coefficient of friction can be obtained, and even if the number of sheets passed increases, the decrease in coefficient of friction can be reduced, and vibrations and impacts that occur during paper feeding are separated from the shaft. Therefore, the generation of abnormal noise called “squeal” can be greatly reduced.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment, and FIG. 1A is a schematic view showing a paper feed roller 10 according to the present invention together with an axis 11. The paper feed roller 10 is fixed to the shaft core 11 by press-fitting the shaft core 11 into the hollow portion of the paper feed roller 10 or by joining them together with an adhesive.

  The paper feed roller 10 is composed of two layers, an outer rubber layer 12 and an inner rubber layer 13. The outer rubber layer 12 is prepared by blending a known crosslinking agent, softening agent and other fillers with EPDM rubber and kneading them, filling the obtained kneaded material into a tube-shaped mold and press vulcanizing. Is obtained. The Shore A hardness of the outer rubber layer 12 in accordance with JIS K6253 is 25.

On the other hand, the inner rubber layer 13 is kneaded by blending butyl rubber with a conventionally known crosslinking agent, softener and other fillers, filling the kneaded product into a mold having a knurled pattern, and press vulcanizing. As shown in FIG. 1B, the outer peripheral surface of the inner rubber layer 13 is provided with a concave portion 13a that is a knurled groove, and a portion that is not the concave portion 13a becomes a convex portion 13b. It is a knurled surface that continues alternately in the direction. The concave portion 13a, which is a knurled groove, has a narrow and recessed shape, and the convex portion 13b has a trapezoidal shape.
The Shore A hardness of the inner rubber layer 13 in accordance with JIS K6253 is 15.

  The outer rubber layer 12 is extrapolated via an adhesive to the inner rubber layer 13 provided with knurled grooves to form the paper feed roller 10. V1 / V2 where V1 is the total volume of the voids formed by the recess 13a and the inner peripheral surface of the outer rubber layer 12, and V2 is the total volume of the inner rubber layer 12 and the outer rubber layer 13. The value is 0.3 or more and 0.7 or less (0.5 in this embodiment).

  With the above-described configuration, the paper feed roller 10 according to the present embodiment can provide wear resistance and a high friction coefficient, and can reduce the decrease in the friction coefficient even when the number of sheets to be passed increases. Occasionally generated vibrations and shocks can be effectively absorbed by the gap inside the roller away from the axis, so that the generation of abnormal noise called “squeal” can be greatly reduced.

FIG. 2 shows a paper feed roller 10-1 of the second embodiment, an outer rubber layer 12-1, an inner rubber layer provided with a concave portion 13a-1 of a knurled groove on the outer peripheral surface, and a convex portion 13b-1. A three-layer structure including 13-1 and an innermost rubber layer 50 disposed on the inner peripheral surface side of the inner rubber layer 13-1.
The outer rubber layer 12-1 and the inner rubber layer 13-1 as an intermediate layer are made of the same rubber composition as in the first embodiment and have a Shore A hardness.
The innermost rubber layer 50 uses the same rubber composition as that of the inner rubber layer 13-1, but the Shore A hardness is set to about 13 slightly lower than that of the rubber layer 13-1.
These three rubber layers 12-1, 13-1, and 50 are individually molded, the inner rubber layer 13-1 is externally fitted to the innermost rubber layer 50, and the inner rubber layer 13-1 is further fitted. The outer rubber layer 12-1 is externally fitted to each other, and each is fixed and integrated through an adhesive.

  The total volume of voids formed by the recess 13a-1 and the inner peripheral surface of the outer rubber layer 12-1 is V1, the innermost rubber layer 50, the inner rubber layer 13-1, and the outer rubber layer 12. The value of V1 / V2 is 0.3 or more and 0.7 or less when the total volume of −1 is V2.

FIG. 3 shows a paper feed roller 10-2 according to the third embodiment. The three-layer structure is the same as that of the second embodiment, and the innermost rubber layer 50-1 is the inner rubber layer 13 (intermediate layer). As with -1, a recess 50a-1 serving as a knurled groove is provided on the outer peripheral surface. The recess 50a-1 is provided at a position corresponding to the inner portion (projection 13b-1) by providing the recess 13a-1 with the rubber layer 13-1.
The sum of the volume of voids formed by the concave portion 13a-1 and the inner peripheral surface of the outer rubber layer 12-1 is V1-1, and is formed by the inner peripheral surface of the concave portion 50a-1 and the rubber layer 13-1. When V1 = V1-1 + V1-2, V1 / V2 is the value of V1 / V2 with respect to the total volume V2 of the three rubber layers 12-1, 13-1, and 50-1. Between 0.3 and 0.7.

Hereinafter, Examples 1-3 and Comparative Examples 1-3 of the paper feed roller of the present invention will be described in detail.
The outer rubber layer and the inner rubber layer of Examples 1 to 3 and Comparative Examples 2 and 3 were prepared based on the formulation shown in Table 1. As the EPDM rubber, “Esprene 670F” manufactured by Sumitomo Chemical was used. This EPDM rubber contains 100 parts by weight of process oil with respect to 100 parts by weight of EPDM polymer. Therefore, half of the numerical values in the table are actual polymer components (rubber content). As the butyl rubber, “Butyl 268” manufactured by JSR was used. As the silicon oxide, “Nippeal VN3” manufactured by Nippon Silica was used. As calcium carbonate, “BF300” manufactured by Bihoku Flourishing Co., Ltd. was used. As the paraffin oil, Idemitsu Kosan "PW-380" was used. As the zinc oxide, “Zinc oxide 2 types” manufactured by Mitsui Metals was used. As stearic acid, “Tsubaki” manufactured by NOF Corporation was used. The carbon black used was “Seast SO” made by Tokai Carbon. Powdered sulfur manufactured by Tsurumi Chemical Industry was used. Tetraethylthiuram disulfide and dibenzothiazyl sulfide used as the vulcanization accelerator were “Noxeller TET” and “Noxeller DM” manufactured by Ouchi Shinsei Chemical.

  The numerical unit of each formulation in the table is parts by weight when the rubber polymer is 100.

  The rubber layer of the inner layer was prepared by kneading all the raw materials of the inner layer at 80 ° C. for 20 minutes with a kneader. A tube-shaped cot having an outer diameter of 15 mm and a length of 60 mm was produced. During press vulcanization, a mold with a knurled pattern is used, and a knurled surface is formed on the outer circumferential surface of the inner rubber layer by alternately forming concave and convex knurled grooves in the circumferential direction. Has been. This cot was cut to a width of 10 mm to form an inner rubber layer.

On the other hand, the rubber layer of the outer layer is obtained by kneading all the raw materials of the outer layer at 80 ° C. for 15 minutes with a kneader, and crosslinking the obtained kneaded material at the same time as molding at 160 ° C. for 20 minutes by press vulcanization. A tube-shaped cot having a diameter of 14 mm, an outer diameter of 21 mm, and a length of 60 mm was produced. This cot was polished with a cylindrical grinder to an outer diameter of 20 mm and cut to a width of 10 mm to form an outer rubber layer.
A paper feed roller was manufactured by press-fitting a cored bar into the hollow portion of the inner rubber layer and fixing the outer rubber layer to the inner rubber layer via an adhesive.

  In Comparative Example 1, a paper feed roller composed of a single layer of solid rubber using the same raw material as the outer rubber layer shown in Table 1 was produced. All raw materials of the outer rubber layer were kneaded in the same manner, and the obtained kneaded material was press-molded at 170 ° C. for 20 minutes and simultaneously crosslinked to form a tube having an inner diameter of 9 mm, an outer diameter of 21 mm, and a length of 38 mm. The cot was made. This cot was polished with a cylindrical grinder to an outer diameter of 20 mm and cut to a 10 mm width. A paper feed roller composed of a single layer of solid rubber was produced by press-fitting a metal core into the hollow portion of the rubber.

(Examples 1-3)
In Example 1, the porosity was 30%, in Example 2, the porosity was 50%, and in Example 3, the porosity was 70%. The void ratio (%) is defined as V1 representing the total volume of voids formed by the knurled grooves of the inner rubber layer and the inner peripheral surface of the outer rubber layer, and V2 representing the total volume of the inner and outer rubber layers. Is a value obtained by (V1 / V2) × 100.

(Comparative Examples 2 and 3)
In Comparative Example 2, the porosity was 20% outside the range, and in Comparative Example 3, the porosity was 80% outside the range.

  For the paper feed rollers of Examples 1 to 3 and Comparative Examples 1 to 3, various evaluations were performed by methods described later. The evaluation results are shown in Table 2.

(Measurement of hardness)
The hardness was measured with a testing machine durometer type A according to the description of “Hardness test method of vulcanized rubber and thermoplastic rubber” of JIS K6253. This hardness is the same as the conventional Shore A which is an international standard.

(Measurement of initial friction coefficient)
As a measurement paper, Fuji Xerox's 60 mm x 210 mm size P paper (plain paper) is set between a paper feed roller and a Teflon (registered trademark) plate, a vertical load of 250 gf is applied to the paper, and a peripheral speed is 300 mm. The paper feed roller is rotated at / sec, and the conveyance force F at that time is measured with a load cell. The coefficient of friction was calculated from F / 250.

(Observation of paper feeding status and friction coefficient after passing 50,000 sheets)
A copying machine “VIVECE 455” (manufactured by Fuji Xerox Co., Ltd.) was equipped with a paper feed roller, 50,000 sheets of the P paper were passed, and the passing condition was visually observed and evaluated. The coefficient of friction after passing 50,000 sheets was also measured in the same manner as described above.

(Evaluation of “squeal”)
A paper feeding roller was attached to the copying machine “VIVECE455” (manufactured by Fuji Xerox), 1000 sheets of the P paper were passed, and the presence of “squeal” was confirmed.

  As shown in Table 2, Examples 1 to 3 in which the porosity was 30 to 70% had a high initial friction coefficient and maintained a high friction coefficient after passing 50,000 sheets. Moreover, it was an excellent paper feed roller without occurrence of squeal.

On the other hand, in Comparative Example 2, since the porosity value was too low, vibrations could not be sufficiently absorbed inside the roller and squeal occurred. Further, the friction coefficient after passing 50,000 sheets was slightly lower than those of Examples 1 to 3.
In Comparative Example 3, since the porosity was too high, the abrasion resistance was poor and 50,000 sheets could not be passed.
Further, in Comparative Example 1 having one solid rubber layer, since there is no gap, vibration cannot be absorbed in the roller and squeal occurs, and the coefficient of friction after passing 50,000 sheets is slightly lower than those in Examples 1 to 3. It became.

  From the above results, the paper feed roller is composed of the inner layer and the outer rubber layer, and the knurled grooves are provided on the outer peripheral surface of the inner layer so that the porosity is 30 to 70%. It was confirmed that even when the number of sheets increased, the coefficient of friction did not decrease greatly and no unpleasant noise called “squeal” occurred.

The paper feed roller of this invention is shown, (A) is a whole schematic diagram, (B) is sectional drawing. It is sectional drawing of the paper feed roller of 2nd embodiment. It is sectional drawing of the paper feed roller of 3rd embodiment. It is sectional drawing of the conventional paper feed roller. It is sectional drawing of the conventional paper feed roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Paper feed roller 11 Shaft core 12 Outer rubber layer 13 Inner rubber layer 13a Concave part (knurl groove)
13b Convex part

Claims (5)

A paper feed roller used by attaching a shaft core to a hollow portion of a rubber roller,
A knurled groove is formed on the outer peripheral surface of any one rubber layer other than the outermost peripheral layer, and is formed by the knurled groove and the inner peripheral surface of the outer peripheral rubber layer. A paper feed roller, wherein a value of V1 / V2 is 0.3 or more and 0.7 or less, where V1 is a total volume of voids and V2 is a total volume of laminated rubber layers.   When the rubber layer on the outer peripheral side of the rubber layer provided with the knurled groove is an outer layer, and the rubber layer provided with the knurled groove and the rubber layer on the inner peripheral side of the rubber layer are used as an inner layer, a shore according to JIS K6253 The paper feed roller according to claim 1, wherein the A hardness is 20 or more and 60 or less in the outer rubber layer, and 15 or less in the inner rubber layer.   The rubber layer on the outer peripheral side in contact with the rubber layer provided with the knurled groove is externally fitted to the rubber layer provided with the knurled groove and integrated through an adhesive. Paper feed roller as described.   The paper feed roller according to any one of claims 1 to 3, wherein the paper feed roller is used as a retard roller. The said outermost peripheral layer consists of a composition containing ethylene-propylene-diene copolymer rubber, and the rubber layer in which the knurled groove | channel is provided consists of a composition containing butyl rubber in any one of Claims 1 thru | or 4. Paper feed roller as described.

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