JP4936992B2 - Paper feed roll manufacturing method - Google Patents

Description

The present invention is an electrophotographic copying machine and used in an electrophotographic apparatus such as a printer, paper feed rolls, it relates to preparation of sheet feed roll such as a transport roll.

  2. Description of the Related Art Generally, a paper feeding system in an electrophotographic apparatus such as an electrophotographic copying machine or a printer has a structure in which paper is fed from a paper tray to a paper separating unit by a pick-up roll, and the paper is separated and fed one by one by the paper separating unit. It is what has. The paper separation unit is usually provided with a double feed prevention mechanism by the FRR method or the FR method so that the paper can be reliably fed one by one.

  Here, in the paper feed system provided with the FRR type double feed prevention mechanism, as shown in FIG. 7, the pickup roll 13 feeds the paper 11 from the paper tray 12 to the paper separation unit, and the paper separation unit feeds the feed roll 14. The retard roll 15 provided in contact with the sheet 11 prevents the paper 11 from being double fed. That is, when two or more sheets of paper 11 are fed, the torque limiter 16 does not reach the limit because it is not affected by the frictional force of the feed roll 14, and the retard roll 15 stops or rotates in the reverse direction and extra. The fed paper 11 is stopped, and only the uppermost paper 11 in contact with the feed roll 14 is fed out.

  As a paper feed roll such as a pickup roll 13, a feed roll 14, and a retard roll 15 used in such a paper feeding system, for example, an ethylene-propylene-diene copolymer ( EPDM) and other olefin rubbers, natural rubber, urethane rubber, foamed urethane and the like are used. In addition, as a method for producing the roll, (1) a method of cutting a cylindrical roll material from a solid rubber material or urethane foam, passing through a cored bar, polishing the surface to make a roll, or (2) a mold A method is generally used in which a metal is molded or foam-molded around a core bar, and then the surface is polished to form a roll.

And since the surface of these paper feed rolls is polished as described above, the polishing allowance in the processing cost is large, which hinders cost reduction. For this reason, polishingless rolls have been studied, and attempts have been made to use rolls having a textured surface (a fine uneven surface due to the textured shape) similar to the polished surface by molding (for example, Patent Documents 1 and 2). reference).
Japanese Patent Laid-Open No. 5-221059 Japanese Patent Laid-Open No. 8-108591

  However, the molding roll (abrasion-less roll) such as a textured surface roll that has been studied so far has a mirror surface portion in contact with the paper on the surface of the roll, so that paper dust generated during the passage of paper tends to adhere and Since it is difficult to escape, it is difficult to stably maintain the friction coefficient for a long time.

  Further, in a conventional mold forming roll (abrasion-less roll) such as a textured surface roll, the inner surface of the molding die is shot blasted or chemically etched to form the surface shape. However, it is difficult to form deep irregularities by shot blasting, and the surface of the convex portion is smooth (pseudo mirror surface) by simple chemical etching, so that it is not possible to achieve the same performance as a polishing surface roll. In addition, it is difficult to obtain a sufficient sheet feeding performance even in the complex shape of these surface states.

  Furthermore, if the texture on the roll surface is lost due to wear due to paper passing, the roll tends to slip during paper feeding and the life of the roll will reach the end of its life. short. Therefore, there is still room for improvement in this respect.

The present invention has been made in view of such circumstances, an inexpensive consists abrasive-less roll, less likely to adhere to the paper dust roll surface caused by paper feeding, roll for paper feeding excellent long-term in the paper feeding properties The purpose is to provide a manufacturing method.

In order to achieve the above object, the present invention provides an abrasive-free paper feed roll comprising a shaft body and a polyurethane elastomer layer formed on the outer periphery thereof, on the outer peripheral surface of the polyurethane elastomer layer. A plurality of concave grooves extending in the circumferential direction are formed at predetermined intervals in the axial direction, and both the outer peripheral surface of the convex band by the portion without the concave groove and the groove bottom of the concave groove have a textured shape. Ru der relates preparation of a paper feed roll fine uneven portion is formed.

And this invention is a manufacturing method of the paper feed roll which has the said structure , Comprising: The cylindrical electrode by which the several recessed groove extended in the circumferential direction is formed in the outer peripheral surface of a metal cylinder, In addition, after preparing a mold base in which a cylindrical hollow hole capable of accommodating the cylindrical electrode is formed, and accommodating the cylindrical electrode in the hollow hole of the mold base, the cylindrical electrode The hollow hole inner peripheral surface is subjected to electric discharge machining into an irregular surface by discharging from the electrode while swinging the metal, and a metal mold is set in the hollow portion of the mold. A paper-feeding roll for producing a roll having an outer peripheral surface formed by casting and crosslinking a polyurethane-based elastomer layer-forming composition into a gap between the mold and the shaft, and transferring the inner peripheral surface of the mold. the preparation, the gist of it.

That is, the present inventor repeated earnest research to solve the above problems, and in the course of the research, the roll was provided with a polyurethane-based elastomer layer excellent in paper feedability, wear resistance, etc. What was formed without polishing by transferring the fine uneven surface (texture) on the inner periphery of the electric discharge machined mold was confirmed by experiment, and it was found that paper feedability was improved even when the entire outer surface of the roll was not in contact with the paper. I found it superior. The present inventor pays attention to this, and forms a plurality of grooves extending in the circumferential direction at predetermined intervals in the axial direction on the outer peripheral surface of the roll, thereby eliminating paper dust and paper without impairing paper feedability. Reminded to improve the powder adhesion prevention. At the same time, when the concave and convex portion is formed on both the outer peripheral surface of the convex band by the portion without the concave groove and the groove bottom of the concave groove, the convex portion of the convex band is worn by durable use of the roll. Even if it becomes flat, the wrinkles at the bottom of the groove will appear due to the wear, so that the wrinkles can continue to feed the paper, and as a result, the life of the roll can be extended, It was found that the paper feeding performance was excellent . And it reached the manufacturing method of this invention as a manufacturing method which can manufacture such a roll of the outstanding performance efficiently .

As described above, the paper feed roll obtained by the production method of the present invention has a plurality of grooves extending in the circumferential direction at predetermined intervals in the axial direction on the outer peripheral surface of the polyurethane-based elastomer layer. A fine uneven portion having a textured shape is formed on both the outer peripheral surface of the convex band by the portion without the concave groove and the groove bottom of the concave groove. For this reason, paper dust is less likely to adhere to the roll surface, and the durability of the friction coefficient due to durable use is higher than that of normal abrasive rolls or textured surface rolls. Some wrinkles appear and the life of the roll is extended, and excellent paper feeding performance can be exhibited over a long period of time.

Then, a cylindrical electrode having a special shape in which a plurality of concave grooves extending in the circumferential direction is formed is accommodated in the hollow hole of the mold base, and the discharge is performed while swinging the hollow electrode. A paper mold having a special shape as described above is manufactured by the manufacturing method of the present invention in which a mold having an uneven surface formed thereon is manufactured and a polyurethane elastomer layer is transferred and formed using the uneven surface of the mold. Rolls can be manufactured.

  Next, embodiments of the present invention will be described in detail.

A paper feed roll obtained by the production method of the present invention includes, for example, as shown in FIG. 1, a shaft body 1 and a polyurethane elastomer layer 2 formed along the outer periphery of the shaft body 1. On the outer peripheral surface of the polyurethane elastomer layer 2, a plurality of concave grooves 2 a extending in the circumferential direction are formed at predetermined intervals in the direction of the shaft body 1, and the outer peripheral surface of the convex band 2 b by a portion without the concave grooves 2 a A fine concavo-convex portion having a textured shape is formed on both the groove bottom of the concave groove 2a. When the cross section of the polyurethane elastomer layer 2 is enlarged, it is as shown in FIG. 2, and H indicates the depth of the groove 2a. With such a configuration, even if the texture on the convex band 2b is worn and flattened due to the use of a roll, the texture on the bottom of the groove 2a appears continuously, so that the paper feeding performance is kept constant. As a result, the life of the roll can be extended.

  In particular, the uneven surface on the outer periphery of the polyurethane elastomer layer 2 is preferably formed so as to satisfy the relationship shown in the following (α). In other words, such an uneven surface is superior in paper feedability, paper dust rejection and paper dust adhesion prevention, and becomes a roll having a longer life. In addition, the depth of the concave groove 2a in the following formula (α) and the surface roughness (Rz) of the fine irregularities due to the embossed shape are determined by, for example, JIS B using a surface roughness measuring device Surfcom 550A (manufactured by Tokyo Seimitsu Co., Ltd.). It can be measured according to 0601. Moreover, the cross-sectional sample of the polyurethane-type elastomer layer 2 may be extract | collected, and the measurement may be performed based on this micrograph.

  And it is preferable that the depth [H of Formula ((alpha))] of the said concave groove 2a is the range of 30-200 micrometers. That is, when the depth of the concave groove 2a is less than 30 μm, when the embossed shape of the convex band 2b has lost its wear, the embossed shape of the concave groove 2a has already progressed, and the paper dust eliminability is reduced. In contrast, if the depth of the concave groove 2a exceeds 200 μm, the concave shape of the concave groove 2a does not come into contact with the paper when the convex shape of the convex band 2b loses wear, and the conveyance force and paper dust are eliminated. This is because the effect cannot be fully exhibited.

  Further, in terms of stable paper feedability, paper dust rejection and paper dust adhesion prevention, the width of the convex band 2b (Wb shown in FIG. 1) is preferably in the range of 3 to 5 mm, and the concave The width of the groove 2a (Wa shown in FIG. 1) is preferably in the range of 3 to 5 mm.

  Further, the surface roughness (Rz) shown in A of the above formula (α) is preferably in the range of 30 to 100 μm from the viewpoint of paper feedability and paper dust adhesion prevention. That is, when the surface roughness (Rz) is less than 30 μm, the roll surface is close to a mirror surface, and paper powder is likely to adhere, and the friction coefficient decreases greatly. Conversely, the surface roughness (Rz) is If it exceeds 100 μm, the surface roughness is too rough, so the initial friction coefficient is small and the conveying force is insufficient. Note that the surface roughness (Rz) of the outer peripheral surface of the convex band 2b and the surface roughness (Rz) of the groove bottom of the concave groove 2a are usually set to be approximately the same. Different values may be used. In this case, A in the above formula (α) is an average value of these.

The JIS-A hardness of the outer peripheral surface of the paper feed roll obtained by the production method of the present invention is preferably in the range of 30 to 80 °, more preferably JIS- A hardness is in the range of 45 to 75 °.

The shaft body 1 which is a constituent material of the paper feed roll obtained by the manufacturing method of the present invention is not particularly limited, and for example, a metal or resin hollow body or solid body is used. Examples of the material include stainless steel, aluminum, polyacetal, and the like. In order to improve the adhesiveness of the polyurethane-based elastomer layer 2, an adhesive, a primer, or the like may be applied to the outer peripheral surface of the shaft body 1 as necessary.

  Further, the material of the polyurethane elastomer layer 2 formed on the outer peripheral surface of the shaft 1 is not particularly limited, but polyether polyurethane is preferable because it is excellent in paper feedability, abrasion resistance and the like.

  And it is preferable to set the thickness of the said polyurethane-type elastomer layer 2 in the range of 2-10 mm from the point of the use use.

The paper feed roll manufacturing method of the present invention can be performed , for example, as follows.

  That is, first, a cylindrical electrode 31 having a special shape as shown in FIG. 3 (a cylindrical electrode in which a plurality of concave grooves extending in the circumferential direction is formed on the outer periphery of a metal cylindrical body) is prepared, together with it. Then, a mold base 32 having a cylindrical hollow hole 32a capable of accommodating the cylindrical electrode 31 is prepared, and the cylindrical electrode 31 is accommodated in the hollow hole 32a of the mold base 32 ( In the direction of the arrow in FIG. FIG. 4 is a view of this state as seen from above. Thereafter, while the cylindrical electrode 31 is swung in a zigzag manner in the direction of the arrow in FIG. 4, the inner peripheral surface of the hollow hole 32a is discharged into an uneven surface by discharge from the cylindrical electrode 31 to form a mold. Make it. Specifically, as shown in the cross-sectional view of FIG. 5, the inner peripheral portion (shaded portion in FIG. 5) of the hollow hole is shaved due to the swinging of the cylindrical electrode 31 (in the direction of the arrow in FIG. 5) and the discharge. A mold 32 ′ having a desired concavo-convex pattern formed on the inner peripheral surface of the mold can be manufactured.

  Next, as shown in FIG. 6, the lower lid 5 is externally fitted to the mold 32 ′ manufactured as described above, and a shaft body (core metal) 1 is prepared, and the shaft is inserted into the hollow portion of the mold 32 ′. Set Body 1 In addition, you may apply | coat an adhesive agent, a primer, etc. to the outer peripheral surface of the said shaft body 1 before the said setting previously. Then, a polyurethane-based elastomer layer 2 forming composition is prepared and cast into the gap between the mold 32 ′ and the shaft body 1, and then the upper lid 7 is fitted on the mold 32 ′. Subsequently, these are heated to crosslink the composition for forming the polyurethane elastomer layer 2 to form the polyurethane elastomer layer 2. Thereafter, the shaft body 1 on which the polyurethane-based elastomer layer 2 is formed is removed from the mold, so that a desired paper feed roll (see FIG. 1) can be obtained. Further, the shaft body 1 may be pulled out and press-fitted into another shaft body (metal shaft, resin core material, etc.).

Such sheet feed roll that obtained in the electrophotographic copying machine, the sheet feed roll and transport roll for use in paper feed system in an electrophotographic apparatus such as a printer, specifically, the pickup roll, feed roll, retard It can be suitably used as a roll or the like.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

[Example 1]
A mixture prepared by mixing a urethane prepolymer with a glycol-based cross-linking agent from an ether-based polyol and an isocyanate is prepared, and an electric discharge machined die is prepared by the method shown in FIGS. 3 to 5, and the core metal is formed by the method shown in FIG. The mixture prepared above was poured into the set mold, then heated to release the mold, and the intended paper feed roll was prepared without polishing.

  Due to the shape of the cylindrical electrode used in the electric discharge machining (a plurality of concave grooves extending in the circumferential direction is formed), convex bands and concave grooves are alternately formed on the inner peripheral surface of the mold. Furthermore, fine wrinkles (two-stage wrinkles) are formed on the inner peripheral surface of the mold by electric discharge machining. And as a result of measuring the dimension and JIS-A hardness of the paper feed roll formed using this metal mold | die, it was as showing in Table 1 of the postscript. In Table 1, the grain roughness A, the groove depth H, the groove width Wa, and the band width Wb (see FIG. 1) were measured using a surface roughness measuring device Surfcom 550A (manufactured by Tokyo Seimitsu Co., Ltd.). It was measured according to B 0601.

[Examples 2 to 7, Comparative Examples 1 and 2]
In Examples 2 to 7, paper feeding rolls were produced by the same manufacturing method as in Example 1 except that the metal mold was subjected to electric discharge machining (processing into a two-stage textured die) by changing the dimensions of the cylindrical electrode. Further, for comparison, a conventional abrasive roll paper feeding roll using EPDM instead of polyurethane elastomer (Comparative Example 1) and a die processed by electric discharge machining with a cylindrical electrode without an uneven surface were formed. Also, a conventional paper-feeding roll with a simple embossed surface (Comparative Example 2) was also produced. The dimensions and JIS-A hardness of these paper feed rolls are also shown in Table 1 and Table 2 below. In addition, these measuring methods are based on Example 1.

  Each of the paper feed rolls thus obtained was used as a feed roll for an FRR bench test machine (see FIG. 7), and an evaluation test was carried out to feed paper continuously at a paper feed speed of 500 mm / sec. The friction coefficient is measured for the initial roll and the roll after feeding 1000K of paper (1 million sheets), and the number of sheets fed until the feed roll reaches the end of its life is measured by a durability test. Evaluated. These results are also shown in Table 3 and Table 4 below. The paper used in this test is A4 paper (trade name: REY) manufactured by INTERNATIONAL PAPER (France).

  From the results of the above table, the paper feeding roll of the example has a large number of sheets fed until the life of the roll, and in particular, the rolls of Examples 1 to 4 show a high coefficient of friction even after 1000K paper feeding. It can be seen that a long life has been achieved. On the other hand, it can be seen that the paper feeding roll of the comparative example has a short life because the number of sheets fed until the life of the roll is smaller than that of the embodiment and the friction coefficient is significantly reduced due to durable use.

It is a perspective view which shows an example of the paper feed roll obtained by the manufacturing method of this invention. It is a principal part enlarged view which shows the cross-sectional shape of the polyurethane-type elastomer layer in the said paper feed roll. It is explanatory drawing which shows the manufacturing process of the metal mold | die of the said paper feed roll. It is explanatory drawing which shows the manufacturing process of the metal mold | die of the said paper feed roll. It is explanatory drawing which shows the manufacturing process of the metal mold | die of the said paper feed roll. It is explanatory drawing which shows the manufacture process of the said paper feed roll. FIG. 4 is an explanatory diagram illustrating an overview inside a sheet feeding device.

Explanation of symbols

1 Shaft 2 Polyurethane Elastomer Layer 2a Groove 2b Convex Belt

Claims (7)

A shaft body, e Bei a polyurethane elastomer layer formed on the outer circumference, in the polyurethane elastomer layer the outer peripheral surface, the grooves extending in a circumferential direction, with which a plurality of formed at predetermined intervals in the axial direction, the A method for producing an abrasive-free paper feed roll, in which fine irregularities are formed on both the outer peripheral surface of a convex band by a portion without a concave groove and the groove bottom of the concave groove. A mold in which a cylindrical electrode having a plurality of grooves extending in the circumferential direction is formed on the outer peripheral surface of a cylindrical body, and a cylindrical hollow hole capable of accommodating the cylindrical electrode is formed with the cylindrical electrode. After the cylindrical electrode is accommodated in the hollow hole of the mold base, the hollow hole inner peripheral surface is made uneven by discharging from the electrode while the cylindrical electrode is swung. The above mold is manufactured by electric discharge machining A metal shaft body is set in the hollow portion, the polyurethane elastomer layer forming composition is cast and crosslinked in the gap between the mold and the shaft body, and the outer periphery is transferred by transferring the inner peripheral surface of the mold. A method for producing a paper feed roll, comprising producing a roll having a surface formed thereon . The polyurethane elastomer layer the outer peripheral surface, according to claim 1 sheet feed roll procedure described you formed so as to satisfy the relationship shown in the following (alpha).

The depth of the groove of the polyurethane elastomer layer the outer peripheral surface, sheet feed roll method according to claim 1 or 2, wherein you formed to be in the range of 30 to 200 [mu] m. The polyurethane elastomer layer the outer peripheral surface of the embossed shape by the surface roughness of the fine unevenness portion (Rz), for paper feeding according to any one of claims 1 to 3 you formed to be in the range of 30~100μm How to make a roll. The width of the convex zone of the polyurethane elastomer layer the outer peripheral surface, sheet feed roll process according to claim 1 you formed to be in the range of 3 to 5 mm. The width of the groove of the polyurethane elastomer layer the outer peripheral surface, sheet feed roll process according to any one of claims 1 to 5 you formed to be in the range of 3 to 5 mm. The JIS-A hardness of the roll outer surface, sheet feed roll process according to any one of claims 1 to 6 you formed to have a range of 30 to 80 °.

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