JP5690160B2 - Paper feed roller - Google Patents

Description

  The present invention relates to a paper feed roller used for paper feed in an electrostatic copying machine, various printers, and the like.

  For example, various paper feed rollers are incorporated in a paper feed mechanism in devices such as an electrostatic copying machine, a laser printer, a plain paper facsimile machine, an ink jet printer, and an automatic cash dispenser (ATM). Examples of the paper feed roller include a paper feed roller, a transport roller, a platen roller, and a paper discharge roller that rotate while contacting paper (including a plastic film, etc.) and convey the paper by friction. It is done.

As the paper feeding roller, conventionally, rollers made of various rubbers such as natural rubber (NR), urethane rubber, ethylene-propylene-diene rubber (EPDM), polynorbornene rubber, silicone rubber, chlorinated polyethylene rubber and the like are generally used. Has been used.
However, paper dust generated from the paper is likely to adhere to the outer peripheral surface of the paper feed roller, and the paper feed roller accumulates on the outer peripheral surface while repeatedly contacting the paper, thereby reducing the friction coefficient of the paper feed roller against the paper. As a result, a paper conveyance failure may occur relatively early.

In recent years, in order to reduce the running cost of the equipment, a lot of cheap paper with a lot of ash is on the market. However, such a paper with a lot of ash tends to generate paper dust, and the accumulation of the paper dust and the conveyance of the paper due to it. Prone to defects.
In Patent Literature 1, at least two cylindrical rubber layers are laminated, and a knurled groove is formed on the outer circumferential surface of at least one rubber layer other than the outermost layer. A paper feed roller having a gap between the rubber layer and the rubber layer is described.

According to such a paper feed roller, by reducing the hardness of the entire rubber layer by the gap, it is said that the contact area of the outer peripheral surface of the paper feed roller with the paper can be increased and the friction coefficient can be increased. .
However, with the above-described configuration, it is impossible to prevent a reduction in the coefficient of friction due to accumulation of paper dust.

JP 2007-15792 A JP-A-8-26511

  An object of the present invention is to provide a paper feed roller that is less likely to cause a reduction in the coefficient of friction due to adhesion of paper dust and can maintain good paper feed for a longer period of time.

The present invention is a cylindrical inner rubber layer, the cylindrical outer rubber layer forming the outer peripheral surface of the paper feed roller is coated on the outer periphery of the inner rubber layer, it is inserted into the center of the front Symbol inner rubber layer shaft And a cylindrical resin core through which the shaft is inserted, and the resin core extends in parallel to each other radially outward from the cylindrical core body and both axial ends of the core body and the middle. A flange, and an area between adjacent flanges is recessed radially inward from the outer peripheral surface of the resin core along the circumferential direction of the resin core and provided at least apart from each other in the axial direction. Two annular recesses are provided, and the inner rubber layer whose outer diameter is smaller than the outer diameter of the flange is fitted in each recess separately between the flanges on both sides forming the recess. And each The radially outer side is sandwiched between the flanges on both sides, and the outer rubber layer is covered with the outer peripheral surface protruding radially outward from the flange. Between the outer rubber layers adjacent to each other in the axial direction, at least one annular groove that is recessed radially inward from the outer peripheral surface is provided along the circumferential direction of the outer peripheral surface of the paper feed roller . Is a paper feed roller characterized by

According to the inventor's study, the coefficient of friction between the paper feed roller and the paper is not uniform over the entire outer peripheral surface of the paper feed roller. The friction coefficient tends to be larger than other regions at both ends in the axial direction of the outer peripheral surface. The both end portions function as contact points of the outer peripheral surface of the paper feed roller with respect to the paper, and the coefficient of friction of the entire paper feed roller is ensured.
On the other hand, according to the present invention, as described above, the annular recess that is recessed inward in the radial direction from the outer circumferential surface along the circumferential direction at a position in the axial direction on the outer circumferential surface of the paper feed roller. Since the groove is provided, the edge portions on both sides of the concave groove on the outer peripheral surface can function as an end portion having a large coefficient of friction, that is, a point of contact with the paper, similarly to the original both end portions.

Therefore, the number of the contact points existing on the outer peripheral surface of one paper feed roller can be increased more than before, and the overall friction coefficient can be improved.
The concave groove also functions to accumulate paper dust generated from the paper and reduce the amount of paper dust accumulated on the outer peripheral surface.
Therefore, according to the paper feed roller of the present invention, it is difficult to reduce the friction coefficient due to the adhesion of paper dust, and good paper feed can be maintained over a longer period.

  In FIG. 1 of Patent Document 2, it appears that a structure similar to the present invention is disclosed at first glance. However, the one described in Patent Document 2 includes a separation roller connected to the shaft through a one-way clutch and a pickup roller integrated with the shaft independently of each other on the same shaft in the axial direction of the shaft. The paper feeding roller is completely different from the paper feeding roller of the present invention.

The paper feed roller of the present invention is rather applied as a separation roller or a pickup roller itself that constitutes the feeding device of Patent Document 2, so that even the feeding device of Patent Document 2 can be used for a longer period of time. Good paper feed is possible over the entire area .

Grooves, for example, by devising the cross-sectional shape of the outer rubber layer, it is conceivable to form the outer rubber layer. Further, the cross-sectional shape of the inner rubber layer is devised to form a groove base in the inner rubber layer, and the outer rubber layer is selectively covered with a portion of the outer periphery of the inner rubber layer other than the groove. It is also conceivable to form a concave groove.
However, since both the rubber layers are pressed against the paper when the paper is fed and repeatedly deformed, when the cross-sectional shape including the concave groove is formed as described above, the deformation is repeated. There is a problem that corners and the like inside the groove are damaged in a relatively short period due to stress concentration.

On the other hand , if it is the structure of this invention, the cross-sectional shape of both rubber layers can be simplified and the damage in the short period by the said stress concentration etc. can be suppressed.
The inner rubber layer is preferably formed of butyl rubber having excellent vibration damping performance near room temperature (5-35 ° C.) in consideration of preventing occurrence of “squealing” due to friction with paper. The outer rubber layer is preferably formed of ethylene propylene rubber having excellent wear resistance in consideration of suppressing the decrease in the friction coefficient due to wear on the outer peripheral surface as much as possible.

The outer rubber layer is preferably coated directly on the outer periphery of the inner rubber layer and integrated with the inner rubber layer by a friction coefficient between the two rubber layers.
Thereby, since it does not adhere | attach via an adhesive agent, it does not carry out vulcanization adhesion, or heat welding, the process and structure which laminate | stack both layers can be simplified, and the cost reduction of a paper feed roller can be achieved. .

In addition, it is not necessary to consider the affinity of the two rubber layers with respect to the adhesive, the vulcanization adhesion between the two rubber layers, or the compatibility at the time of heat welding. A rubber having excellent characteristics can be selected and used, and versatility of both rubber layers can be improved.
When the outer rubber layer is worn, only the outer rubber layer needs to be replaced, and the labor and cost of replacement can be omitted.

  According to the present invention, it is possible to provide a paper feed roller that is less likely to cause a reduction in the coefficient of friction due to adhesion of paper dust and can maintain good paper feed for a longer period of time.

FIG. 3 is a partially cutaway perspective view showing an appearance of an example of the embodiment of the paper feed roller of the present invention. It is sectional drawing which shows the internal structure of the paper feed roller of the said example. It is a disassembled perspective view which shows the state which decomposed | disassembled the paper feed roller of the said example into each part.

FIG. 1 is a partially cutaway perspective view showing the appearance of an example of an embodiment of a paper feed roller of the present invention. FIG. 2 is a cross-sectional view showing the internal structure of the paper feed roller of the above example. FIG. 3 is an exploded perspective view showing a state in which the paper feed roller of the above example is disassembled into various parts.
1 to 3, a paper feed roller 1 of this example includes a shaft 2, a cylindrical resin core 3 through which the shaft 2 is inserted, and two cylindrical shapes fitted to the outer periphery of the resin core 3. Inner rubber layer 4 and two cylindrical outer rubber layers 5 fitted to the outer peripheries of the two inner rubber layers 4, respectively. The shaft 2, the resin core 3, the inner rubber layer 4, and the outer rubber layer 5 are each arranged concentrically.

The outer rubber layer 5 constitutes the outer peripheral surface of the paper feed roller 1. That is, the outer peripheral surface 6 of the outer rubber layer 5 is the outer peripheral surface of the paper feed roller 1.
Two inner rubber layers 4 and two outer rubber layers 5 are provided to be spaced apart from each other in the axial direction of the resin core 3, and between the adjacent inner rubber layers 4 and between the outer rubber layers 5, An annular groove 7 that is recessed radially inward from the outer peripheral surface 6 is formed.

In the example shown in the figure, the shaft 2 is formed in a columnar shape having a constant diameter, for example, by resin or metal.
The resin core 3 includes a cylindrical core body 9 having a through hole 8 through which the shaft 2 is inserted at the center, a pair of outer flanges 10 provided at both ends of the core body 9 in the axial direction, and the core body. 9 is provided with one middle flange 11 provided at the center in the axial direction. The resin core 3 is configured by, for example, integrally molding the respective parts with a relatively hard resin.

The through hole 8 has a constant inner diameter, and the core body 9 has a constant outer diameter. The outer peripheral surface 12 of the core body 9 is disposed concentrically with the inner peripheral surface of the through hole 8 and the shaft 2 inserted into the through hole 8.
The outer flange 10 and the intermediate flange 11 both extend radially outward perpendicular to the axial direction of the core body 9 and are arranged in parallel to each other in the surface direction.

Each of the flanges 10 and 11 is formed in a disk shape having the same diameter and a constant thickness.
The outer edges of the flanges 10 and 11 are arranged concentrically with the inner peripheral surface of the through-hole 8 and the outer peripheral surface of the shaft 2 inserted into the through-hole 8, respectively. A surface 13 is formed. The outer peripheral surface 13 is disposed concentrically with the outer peripheral surface 12 of the core body 9, the inner peripheral surface of the through hole 8, and the shaft 2 inserted into the through hole 8.

A region between one of the pair of outer flanges 10 and the intermediate flange 11 is a recess 14 that is recessed radially inward from the outer peripheral surface 13 to reach the outer peripheral surface 12 of the core body 9. . A region between the other outer flange 10 and the intermediate flange 11 is also a recess 14 that is recessed radially inward from the outer peripheral surface 13 to reach the outer peripheral surface 12 of the core body 9.
Both concave portions 14 are formed in an annular shape along the circumferential direction of the outer peripheral surface 13. Further, the both concave portions 14 are provided so as to be separated from each other in the axial direction over the entire circumference by separating the intermediate flange 11.

Further, as described above, the outer flange 10 and the intermediate flange 11 are disposed in parallel to each other in the surface direction, so that both the recesses 14 have a constant axial width over the entire circumference of the outer peripheral surface 13. Is formed. Moreover, in the example of a figure, the width | variety of both the recessed parts 14 is equal because a pair of outer flange 10 and the intermediate | middle flange 11 are provided in the axial direction at equal intervals.
Furthermore, both the concave portions 14 are arranged so that the outer peripheral surface 13 of the resin core 3 and the outer peripheral surface 12 of the core body 9 are concentrically arranged as described above, so that the entire periphery of the outer peripheral surface 13 has a depth. Are formed constant and the depths of the two are equal.

The inner rubber layer 4 is formed in a cylindrical shape having a constant outer diameter and having a through hole 15 through which the core body 9 of the resin core 3 is inserted. The through-hole 15 has a constant inner diameter and is concentrically disposed at the center of the inner rubber layer 4. That is, the inner peripheral surface of the through hole 15 is disposed concentrically with the outer peripheral surface 16 of the inner rubber layer 4.
Both end surfaces in the axial direction of the inner rubber layer 4 are flat surfaces orthogonal to the axial direction. The length between the both end faces of the inner rubber layer 4 (length in the axial direction) is equal to the axial distance between the outer flange 10 and the intermediate flange 11 of the resin core 3.

The inner rubber layer 4 is made of, for example, rubber such as nitrile rubber (NBR), butyl rubber (IIR), styrene butadiene rubber (SBR), natural rubber, urethane rubber, thermoplastic elastomer such as styrene-based thermoplastic elastomer, polyethylene, polypropylene, etc. It is formed of one kind or two or more kinds such as a soft resin.
In particular, the inner rubber layer 4 is preferably formed of butyl rubber. The butyl rubber is particularly excellent in vibration damping performance near room temperature (5 to 35 ° C.), and therefore has an excellent effect of preventing the occurrence of the “squeal” due to friction with paper.

The inner rubber layer 4 may be porous or non-porous. In consideration of improving the vibration damping performance of the inner rubber layer 4, it is preferably porous, but in view of durability, it is preferably non-porous. In particular, in consideration of achieving both vibration damping performance and durability, the non-porous inner rubber layer 4 made of the butyl rubber is preferable.
The inner rubber layer 4 is formed by molding a rubber composition containing butyl rubber or the like into a cylindrical shape by, for example, press vulcanization and cutting it into a predetermined length.

The two inner rubber layers 4 are respectively fitted in the recesses 14 of the resin core 3.
As described above, the two concave portions 14 are formed so as to be spaced apart from each other in the axial direction of the resin core 3 over the entire circumference. For this reason, the inner rubber layers 4 fitted in the respective recesses 14 are also arranged apart from each other in the axial direction over the entire circumference. Accordingly, a base portion of the annular groove 7 is formed between the adjacent inner rubber layers 4.

The inner diameter of the through hole 15 is equal to or slightly smaller than the outer diameter of the core body 9 of the resin core 3. Therefore, each inner rubber layer 4 is directly covered on the outer periphery of the core body 9 of the resin core 3 by the fitting, and is integrated with the resin core 3 by friction of the inner rubber layer 4.
Thereby, the process which adhere | attaches via an adhesive agent or heat welding is abbreviate | omitted, and the cost reduction of the paper feed roller 1 can be achieved.

In addition, since it is not necessary to consider the affinity of the inner rubber layer 4 and the resin core 3 to the adhesive or compatibility at the time of heat welding, the rubber excellent in the characteristics required for the inner rubber layer 4 as described above. Can be selected and used, and the versatility of the inner rubber layer 4 can also be improved.
Further, for example, when the inner rubber layer 4 is damaged, only the inner rubber layer 4 needs to be replaced, and the labor and cost of replacement can be omitted.

The outer diameter of the inner rubber layer 4 is made smaller than the outer diameters of both flanges 10 and 11, whereby the both flanges 10 and 11 have a diameter larger than the outer peripheral surface 16 of the inner rubber layer 4 fitted in the recess 14. It protrudes outward in the direction.
The outer rubber layer 5 is formed in a cylindrical shape having a constant outer diameter provided with a through hole 17 through which the inner rubber layer 4 is inserted. The through-hole 17 has a constant inner diameter and is concentrically disposed at the center of the outer rubber layer 5. That is, the inner peripheral surface of the through hole 17 is disposed concentrically with the outer peripheral surface 6 of the outer rubber layer 5.

Both end surfaces in the axial direction of the outer rubber layer 5 are planes orthogonal to the axial direction. The length between the both end faces of the outer rubber layer 5 (the length in the axial direction) is made equal to the axial distance between the outer flange 10 and the intermediate flange 11 of the resin core 3.
The outer rubber layer 5 is made of, for example, rubber such as ethylene propylene rubber (EPDM, EPM), urethane rubber, NBR, thermoplastic elastomer such as polyester-based thermoplastic elastomer, styrene-based thermoplastic elastomer, urethane-based thermoplastic elastomer, polyethylene, polypropylene, etc. It is formed by 1 type, or 2 or more types, such as soft resins.

In particular, the outer rubber layer 5 is preferably formed of ethylene propylene rubber, especially EPDM. Since the ethylene propylene rubber is excellent in wear resistance, it is possible to suppress a decrease in the friction coefficient due to wear on the outer peripheral surface as much as possible.
The outer rubber layer 5 may be porous or non-porous. In consideration of improving the coefficient of friction of the outer rubber layer 5 with respect to the paper, it is preferably porous, but considering durability, it is preferably non-porous. In particular, the non-porous outer rubber layer 5 made of EPDM is preferable in consideration of achieving both a coefficient of friction and durability.

The outer rubber layer 5 is formed by molding a rubber composition containing EPDM or the like into a cylindrical shape by, for example, press vulcanization and cutting it to a predetermined length.
The two outer rubber layers 5 are individually coated on the outer periphery of the inner rubber layer 4 fitted in the recess 14 of the resin core 3. The two outer rubber layers 5 are sandwiched between both flanges 10 and 11 projecting radially outward from the outer periphery of the inner rubber layer 4.

As described above, the two concave portions 14 are formed so as to be spaced apart from each other in the axial direction of the resin core 3 over the entire circumference. In addition, the inner rubber layers 4 fitted in the respective recesses 14 are also arranged apart from each other in the axial direction over the entire circumference.
Therefore, the two outer rubber layers 5 covered on the outer periphery of each inner rubber layer 4 in a state sandwiched between both flanges 10 and 11 are also arranged apart from each other in the axial direction over the entire periphery. It is installed. Therefore, the annular concave groove 7 is formed between the adjacent outer rubber layers 5.

The inner diameter of the through hole 17 is equal to or slightly smaller than the outer diameter of the inner rubber layer 4. Therefore, each outer rubber layer 5 is directly covered on the outer periphery of the inner rubber layer 4 by the coating, and is integrated with each other by friction between the rubber layers 4 and 5.
Thereby, since it does not adhere via an adhesive, vulcanization adhesion, or heat welding, the process and configuration for laminating both rubber layers 4 and 5 are simplified, and the cost of the paper feed roller 1 is reduced. Can be achieved.

Moreover, since it is not necessary to consider the affinity of the rubber layers 4 and 5 to the adhesive, the vulcanization adhesion between the rubber layers 4 and 5 or the compatibility at the time of thermal welding, It is possible to select and use a rubber excellent in the characteristics required for the rubber layers 4 and 5 and to improve the versatility of the rubber layers 4 and 5.
Further, when the outer rubber layer 5 is worn, only the outer rubber layer 5 needs to be replaced, and the labor and cost of replacement can be omitted.

In the paper feed roller 1 of this example provided with the above-described portions, both end portions P1 in the axial direction of the outer peripheral surface 6 can function as contact points with the paper. Not only that, the edge portions P2 on both sides of the concave groove 7 can function as end portions having a large friction coefficient, that is, contact points to the paper, similarly to the original both end portions P1.
Therefore, the number of the contact points existing on the outer peripheral surface 6 of one paper feed roller 1 can be increased more than before, and the overall friction coefficient can be improved.

The concave groove 7 also functions to accumulate paper dust generated from the paper and reduce the amount of paper dust accumulated on the outer peripheral surface 6.
Therefore, according to the paper feed roller 1, it is difficult to reduce the friction coefficient due to the adhesion of paper dust, and it is possible to maintain good paper feed for a longer period.
In addition, the structure of this invention is not limited to the example of FIGS. 1-3 demonstrated above.

For example, two or more concave grooves 7 may be provided. In that case, for example, by forming two or more intermediate flanges 11 between the outer flanges 10 of the resin core 3, three or more recesses 14 are provided on the outer peripheral surface 13 of the resin core 3. The inner rubber layers 4 may be fitted together one by one, and the outer circumference of each inner rubber layer 4 may be covered with the outer rubber layer 5.
As will be apparent from the results of the examples described later, as the number of the concave grooves 7 is increased, the friction coefficient due to the adhesion of paper powder is less likely to be reduced, and good paper feeding is maintained over a longer period. It becomes possible.

However, since the area of the outer peripheral surface 6 decreases as the number of the concave grooves 7 is increased, if the number is increased too much, the friction coefficient may be lowered. Therefore, it is preferable that the number of the concave grooves 7 provided on the outer peripheral surface 6 is appropriately set according to the total axial length of the outer peripheral surface 6, the axial width of the concave grooves 7, and the like.
There is no particular limitation as to how much the width of the groove 7 in the axial direction is set. However, if the width is too narrow, the outer rubber layers on both sides of the groove 7 are deformed when pressed against the paper during paper feeding. 5 may come into contact, and the effect of providing the concave groove 7 may not be sufficiently exhibited. Moreover, since the area of the outer peripheral surface 6 will reduce when too large, there exists a possibility that a friction coefficient may fall. Therefore, the width of the concave groove 7 is appropriately set according to the hardness of the rubber layers 4 and 5, the outer diameter of the outer peripheral surface 6, the total axial length of the outer peripheral surface 6, the number of the concave grooves 7, and the like. preferable.

The hardness and thickness of both rubber layers 4 and 5 can be arbitrarily set. In either case, the function of the concave groove 7 makes it possible to maintain good paper feeding over a long period of time.
In addition, various design changes can be made without departing from the scope of the present invention.

<Example 1>
(Production of inner rubber layer)
Each component shown in Table 1 was press vulcanized at 160 ° C. for 30 minutes to form a cylindrical body (cot) having an inner diameter φ12.6, an outer diameter φ21, and a length of 60 mm and serving as an inner rubber layer. Next, this cylindrical body was cut to a length of 13.5 mm to produce a cylindrical inner rubber layer 4 shown in FIGS.

Each component in Table 1 is as follows.
Butyl rubber: Butyl 268 manufactured by ExxonMobil
Calcium carbonate: BF300 manufactured by Bihoku Powder Chemical Co., Ltd.
Carbon black HAF: Seast 3 made by Tokai Carbon Co., Ltd.
Paraffin oil: Diana (registered trademark) process oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.
2 types of zinc oxide: manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: trade name “Tsubaki” manufactured by NOF Corporation
Powdered sulfur: Tsurumi Chemical Co., Ltd. accelerator TBT: Ouchi Shinsei Chemical Co., Ltd. Noxeller (registered trademark) TBT, tetrabutyl thiuram disulfide accelerator DM: Ouchi Shinsei Chemical Industry Co., Ltd. DM, di-2-benzothiazolyl disulfide (Preparation of outer rubber layer)
Each component shown in Table 2 was subjected to press vulcanization at 160 ° C. for 20 minutes to form a cylindrical body (cott) having an inner diameter φ14, an outer diameter φ25, and a length of 60 mm as a base of the inner rubber layer. Next, this cylindrical body was polished using a cylindrical grinder until the outer diameter became φ24, and further cut to a length of 13.5 mm to produce the cylindrical outer rubber layer 5 shown in FIGS. 1 to 3. .

EPDM, silicon oxide, titanium oxide, and accelerator TET in Table 2 are as follows. Other ingredients are the same as in Table 1.
EPDM: Esprene (registered trademark) 670F manufactured by Sumitomo Chemical Co., Ltd., oil-extended EPDM, EPDM: oil-extended oil = 100: 100 (mass ratio)
Silicon oxide: Nipsil (registered trademark) VN3 manufactured by Tosoh Silica Corporation
Titanium oxide: Trade name Kronos KR380 manufactured by Titanium Industry Co., Ltd.
Accelerator TET: Noxeller TET manufactured by Ouchi Shinsei Chemical Co., Ltd., tetraethylthiuram disulfide (resin core)
The entire resin core 3 is formed of a hard resin into the three-dimensional shape shown in FIGS. 1 to 3. The core body 9 has an outer diameter of 14 mm, the flanges 10 and 11 have an outer diameter of 22 mm, and a thickness of 1. .5 mm, the number of the intermediate flanges 11 is one, the number of the concave portions 14 is two, the axial distance between the flanges 10, 11, that is, the axial width of the two concave portions 14 is 13.5 mm. I prepared something.

(Paper feed roller)
The inner rubber layer 4 is fitted in the two recesses 14 of the resin core 3 and the outer rubber layer 5 is coated on the outer circumference of the inner rubber layer 4 to form the paper shown in FIGS. A feed roller 1 was constructed.
The outer diameter of the outer circumferential surface 6 constituted by the outer rubber layer 5 of the paper feed roller 1 is 24.6 mm, the total length in the axial direction is 28.5 mm, the number of the concave grooves 7 is one, and the axial direction of the concave grooves 7 The width of was 1.5 mm.

<Example 2>
The inner rubber layer 4 was prepared by cutting the same cylindrical body formed in Example 1 to a length of 8.5 mm. As the outer rubber layer 5, the same cylindrical body as that formed in Example 1 was polished using a cylindrical grinder until the outer diameter was φ24, and further cut to a length of 8.5 mm. .

As the resin core 3, the outer diameter of the core body 9 and the outer diameters and thicknesses of the flanges 10 and 11 are the same as those in the first embodiment, the number of the intermediate flanges 11 is two, the number of the recesses 14 is three, The axial distance between 10 and 11, that is, the axial width of the three recesses 14 was 8.5 mm.
The inner rubber layer 4 was fitted into the three recesses 14 of the resin core 3, and the outer rubber layer 5 was coated on the outer periphery of the inner rubber layer 4 to constitute the paper feed roller 1.

The outer diameter of the outer peripheral surface 6 constituted by the outer rubber layer 5 of the paper feed roller 1 is 24.6 mm, the total length in the axial direction is 28.5 mm, the number of the concave grooves 7 is two, and the axial direction of the concave grooves 7 The width of was 1.5 mm.
<Example 3>
The inner rubber layer 4 was prepared by cutting the same cylindrical body formed in Example 1 into a length of 6 mm. As the outer rubber layer 5, the same cylindrical body as that formed in Example 1 was polished using a cylindrical grinder until the outer diameter became φ24, and further cut into a length of 6 mm.

As the resin core 3, the outer diameter of the core body 9 and the outer diameters and thicknesses of the flanges 10 and 11 are the same as those in the first embodiment, the number of the intermediate flanges 11 is three, the number of the recesses 14 is four, The axial distance between 10 and 11, that is, the axial width of the four recesses 14 was 6 mm.
The inner rubber layer 4 was fitted into the four recesses 14 of the resin core 3, and the outer rubber layer 5 was coated on the outer periphery of the inner rubber layer 4 to constitute the paper feed roller 1.

The outer diameter of the outer peripheral surface 6 constituted by the outer rubber layer 5 of the paper feed roller 1 is 24.6 mm, the total length in the axial direction is 28.5 mm, the number of the concave grooves 7 is three, and the axial direction of the concave grooves 7 is The width of was 1.5 mm.
<Comparative example 1>
The inner rubber layer 4 was prepared by cutting the same cylindrical body formed in Example 1 into a length of 28.5 mm. As the outer rubber layer 5, the same cylindrical body as that formed in Example 1 was polished using a cylindrical grinder until the outer diameter was φ24 and further cut to a length of 28.5 mm. .

As the resin core 3, the outer diameter of the core body 9 and the outer diameter and thickness of the outer flange 10 are the same as those of the first embodiment, the intermediate flange 11 is not provided (the number is 0), the number of the concave portions 14 is one, the outer flange An axial interval between 10, that is, one recess 14 having an axial width of 28.5 mm was prepared.
The inner rubber layer 4 was fitted into one recess 14 of the resin core 3 and the outer rubber layer 5 was coated on the outer periphery of the inner rubber layer 4 to constitute the paper feed roller 1.

The outer diameter of the outer peripheral surface 6 constituted by the outer rubber layer 5 of the paper feed roller 1 was 24.6 mm, the total length in the axial direction was 28.5 mm, and the number of grooves 7 was zero.
<Friction coefficient test and paper passing status evaluation>
The paper feeding roller of each example and comparative example was incorporated into a laser printer HP Laser Jet 4350n manufactured by Hewlett-Packard Japan, and 10,000 sheets of paper [Xerox Business 4200 manufactured by Xerox Co., Ltd.] were passed.

Next, the paper feed roller is taken out and pressed onto a paper of 60 mm wide × 120 mm long (Xerox Business 4200 made by Xerox Co., Ltd.) placed on a Teflon (registered trademark) plate while applying a vertical load of 300 gf. In this state, when the sheet is rotated at a peripheral speed of 150 mm / second, the conveyance force F applied to the paper is measured using a load cell, and the formula (1):
Friction coefficient = F / 300 (1)
Thus, the coefficient of friction after durability was obtained.

In addition, the number of times of paper feeding failure was recorded during the continuous paper feeding.
The results are shown in Table 3.

From the results of Examples 1 to 3 and Comparative Example 1 in the table, by providing a concave groove on the outer peripheral surface as the structure of FIGS. It has been found that good paper feed can be maintained over a period of time. Moreover, it turned out from the result which compared Examples 1-3 that the said effect can be improved, so that the number of concave grooves is increased.

DESCRIPTION OF SYMBOLS 1 Paper feed roller 2 Shaft 3 Resin core 4 Inner rubber layer 5 Outer rubber layer 6 Outer peripheral surface 7 Concave groove 8 Through hole 9 Core main body 10 Outer flange 11 Middle flange 12 Outer peripheral surface 13 Outer peripheral surface 14 Recess 15 Through hole 16 Outer peripheral surface 17 Through hole P1 Both ends P2 Edge

Claims (3)

A paper feed roller, through tubular inner rubber layer, the cylindrical outer rubber layer forming the outer peripheral surface of the paper feed roller is coated on the outer periphery of the inner rubber layer, in the center of the front Symbol inner rubber layer And a cylindrical resin core through which the shaft is inserted, and the resin core extends in parallel with each other from the cylindrical core body and both axial ends of the core body to the radially outward direction. And an area between adjacent flanges is recessed radially inward from the outer peripheral surface of the resin core along the circumferential direction of the resin core, and spaced apart from each other in the axial direction. The inner rubber layer having an outer diameter smaller than the outer diameter of the flange in a state in which the outer diameter is at least two annular recesses and is sandwiched between the flanges on both sides forming the recesses separately. Fit In addition, the outer rubber layer covers the outer rubber layer in a state in which the radially inner side is sandwiched between the flanges on both sides and the outer peripheral surface protrudes radially outward from the flange. In addition, at least one annular groove that is recessed radially inward from the outer peripheral surface is provided between the outer rubber layers adjacent to each other in the axial direction along the circumferential direction of the outer peripheral surface of the paper feed roller. A paper feed roller characterized by being made. The paper feed roller according to claim 1 , wherein the inner rubber layer is made of butyl rubber and the outer rubber layer is made of ethylene propylene rubber. The paper feed roller according to claim 1 or 2 , wherein the outer rubber layer is directly coated on an outer periphery of the inner rubber layer and integrated with the inner rubber layer by friction between the two rubber layers.

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