JP4367409B2 - Feed roller - Google Patents

Description

  The present invention relates to a paper feed roller such as a pick-up roller, a feed roller, a reverse roller, and a transport roller that is used for transporting paper in a machine such as a copying machine, a printer, and a facsimile machine.

  A paper feed roller used in a copying machine or the like is required to have excellent wear resistance and maintain a coefficient of friction over a long period of time. Furthermore, a sheet having a low hardness is required from the viewpoints of performance of separating the sheet (securing the nip width), prevention of damage to the sheet, and the like.

In view of this, conventionally, a paper feed roller has been proposed in which an elastic layer having a single-layer structure or a two-layer structure is formed on the outer peripheral surface of a hub (shaft body). Examples of the elastic layer having a single-layer structure include, for example, a structure in which through holes parallel to the rotation axis are formed at predetermined intervals in the circumferential direction at a position slightly inward from the outer peripheral surface of the elastic layer. It has been proposed (see Patent Document 1). In addition, as an elastic layer having a two-layer structure, for example, an inner layer made of a foamed cured body such as urethane rubber and an outer layer made of a non-foamed cured body such as silicone rubber has been proposed (Patent Literature). 2).
Japanese Patent Laid-Open No. 11-29238 Japanese Patent No. 3571983

  On the other hand, the hub (shaft body) of the paper feed roller is attached to a torque limiter, a motor or the like, and may generate heat due to frictional heat due to sliding rotation with the torque limiter, heat conduction from the motor, or the like. In addition, the inside of a device such as a copying machine may become hot. When the heat is transmitted to the elastic layer, the hardness of the elastic layer may change or the elastic layer itself may be modified, and the paper transportability may deteriorate.

  However, in Patent Document 1, although the elastic layer is easily deformed and reduced in hardness by the through holes formed in the elastic layer, heat dissipation is not considered, and the elastic layer is a single layer. Due to the layer structure, there is a limit in wear resistance and friction coefficient maintenance. Moreover, although the thing of the said patent document 2 also makes the elastic layer low hardness by making an inner layer into a foaming hardening body, heat dissipation is not considered.

  The present invention has been made in view of such circumstances, and it is possible to reduce the hardness while ensuring the wear resistance and the friction coefficient maintenance property, and to provide a paper feed roller excellent in heat dissipation. Objective.

  In order to achieve the above object, a paper feed roller of the present invention is a paper feed roller comprising a hub and an elastic layer formed on the outer peripheral surface of the hub, and the elastic layer is composed of an inner layer and an outer layer. The inner layer is made of a non-foamed cured body of thermosetting urethane rubber, and the outer layer is made of a non-foamed cured body of thermosetting urethane rubber, and has a higher hardness than the non-foamed cured body of the inner layer. A plurality of through holes extending in the axial direction are formed at predetermined intervals over the entire circumference in the circumferential direction, and the inner diameter of the through holes is set within a range of 38 to 16% of the outer diameter of the hub. The shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub is set in a range of 0.5 to 3.0 mm.

  In the paper feeding roller of the present invention, the inner layer and the outer layer are both made of a non-foamed cured body of thermosetting urethane rubber, and the non-foamed cured body of the outer layer is set to have a higher hardness than that of the inner layer. ing. Further, the inner layer has a specific through hole (inner diameter is in the range of 38 to 16% of the outer diameter of the hub, and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub is in the range of 0.5 to 3.0 mm. By forming the inner layer, the through-hole portion of the inner layer is easily deformed, and the hardness of the inner layer is appropriately softened in combination with the non-foamed cured body of the inner layer. For these reasons, the hardness of the surface of the elastic layer composed of the inner layer and the outer layer and the overall softness combine to ensure the wear resistance and the friction coefficient maintainability, while maintaining the entire elastic layer to an appropriate hardness. can do. Moreover, the said specific through-hole formed in the inner layer can improve the heat dissipation of a hub and an inner layer together with the non-foaming hardening body of an inner layer.

  In particular, the ASKER-C hardness of the non-foamed cured body of the inner layer is set in the range of 20 to 70 degrees, the JIS-A hardness of the non-foamed cured body of the outer layer is set in the range of 40 to 80 degrees, When the JIS-A hardness measured from the outer layer side of the elastic layer composed of the inner layer in which the through-hole is formed and the outer layer is set within a range of 5 to 45 degrees, the paper feeding roller is used as an abrasion resistance. In addition, the coefficient of friction maintenance is suitable, and the hardness of the entire elastic layer is also suitable.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this.

  1 and 2 show an embodiment of a paper feed roller of the present invention. This paper feed roller is composed of a cylindrical hub 1, an inner layer 2 formed on the outer peripheral surface of the hub 1, and an outer layer 3 formed on the outer peripheral surface of the inner layer 2. The outer layer 3 is made of a non-foamed cured body of thermosetting urethane rubber. The non-foamed cured body of the outer layer 3 is set to have a higher hardness than that of the inner layer 2. The inner layer 2 is formed with a plurality of (12 in FIG. 2) through-holes 4 extending in the axial direction at predetermined intervals along the entire circumference. The inner diameter A of the through hole 4 is set within a range of 38 to 16% of the outer diameter B of the hub 1, and the shortest distance C between the inner peripheral surface of the through hole 4 and the outer peripheral surface of the hub 1 is , 0.5 to 3.0 mm.

  The outer diameter B of the hub 1 is normally set within a range of 8 to 20 mm from the viewpoint of making it suitable as a paper feed roller. The thickness of the inner layer 2 is set in the range of 3 to 30 mm from the viewpoint of setting the inner layer 2 to an appropriate hardness in consideration of the non-foamed cured body constituting the inner layer 2 and the specific through-hole 4. The Furthermore, the thickness of the outer layer 3 is also set within a range of 0.2 to 3 mm from the viewpoint of setting the outer layer 3 to an appropriate hardness in consideration of the non-foamed cured body constituting the outer layer 3.

  Thus, by forming the specific through-hole 4 in the inner layer 2 made of the non-foamed cured body of the thermosetting urethane rubber, the heat dissipation of the hub 1 and the inner layer 2 becomes excellent, and the inner layer The hardness of 2 is made appropriate. Furthermore, by forming the outer layer 3 on the outer peripheral surface of the inner layer 2 and setting the hardness of the non-foamed cured body of the outer layer 3 higher than the hardness of the non-foamed cured body of the inner layer 2, the inner layer 2 and the outer layer 3 The surface of the elastic layer is made hard and the entire elastic layer is softened to ensure wear resistance and friction coefficient maintenance.

  More specifically, the reason why the inner diameter A of the through hole 4 is set in the range of 38 to 16% of the outer diameter B of the hub 1 is that the inner diameter A of the through hole 4 is 16 of the outer diameter B of the hub 1. %, The area of the inner peripheral surface of the through hole 4 becomes too small with respect to the area of the outer peripheral surface of the hub 1, so that the heat dissipation of the inner layer 2 is lowered and the inner diameter A of the through hole 4 is also reduced. For this reason, the amount of deformation of the through-hole 4 becomes insufficient, and the hardness of the inner layer 2 does not sufficiently decrease, so that a sufficient nip width with the sheet cannot be obtained, and the sheet transportability is decreased. On the contrary, if the inner diameter A of the through hole 4 exceeds 38% of the outer diameter B of the hub 1, the heat dissipation of the inner layer 2 is improved, but the hardness of the inner layer 2 is too low, so that the contact force with the paper is sufficient. This is because the sheet transportability is deteriorated.

  The reason for setting the shortest distance C between the inner peripheral surface of the through hole 4 and the outer peripheral surface of the hub 1 within the range of 0.5 to 3.0 mm is that the shortest distance C is less than 0.5 mm. This is because the rubber thickness of the inner layer 2 on the inner side of the through hole 4 becomes thin, so that the moldability is deteriorated and the strength is insufficient, and the press-fitting into the hub 1 becomes difficult. Conversely, the shortest distance C is 3.0 mm. This is because the position of the through hole 4 is too far from the outer peripheral surface of the hub 1 and the heat dissipation of the hub 1 is deteriorated.

  Furthermore, the shortest distance D between the inner peripheral surfaces of the adjacent through holes 4 is within a range of 1.0 to 3.0 mm from the viewpoint of making the heat dissipation, the hardness of the inner layer 2 and the hardness of the entire elastic layer appropriate. It is preferably set, and more preferably in the range of 1.5 to 2.5 mm.

  The inner diameter A of the through hole 4, the shortest distance C between the inner peripheral surface of the through hole 4 and the outer peripheral surface of the hub 1, and the shortest distance D between the inner peripheral surfaces of adjacent through holes 4 are along the axial direction. The average value of the values measured at the respective cross sections of the inner layer 2 cut in the thickness direction at any 10 locations. The cross-sectional shape of the through hole 4 is preferably a circle, but may be an ellipse, a polygon such as a quadrangle, and the inner diameter A of each through hole 4 is an average of the maximum diameter and the minimum diameter of each through hole 4. ing.

  Regarding the hardness of the non-foamed cured body of the inner layer 2 and the outer layer 3, from the viewpoint of making the paper feed roller more appropriate, the hardness of the non-foamed cured body of the inner layer 2 is an ASKER-C hardness of 20 to 70 degrees. It is preferably set within the range, more preferably within the range of 30 to 50 degrees. Further, the hardness of the non-foamed cured body of the outer layer 3 is preferably set in the range of JIS-A hardness of 40 to 80 degrees, more preferably in the range of 50 to 70 degrees. And the hardness measured from the outer layer 3 side of the elastic layer consisting of the inner layer 2 and the outer layer 3 is preferably set within a range of JIS-A hardness of 5 to 45 degrees, more preferably 10 to 30 degrees. Within range.

  In addition, the ASKER-C hardness of the non-foamed cured body of the inner layer 2 is a prototype composed of only the non-foamed cured body of the inner layer 2 (one in which the through hole 4 is not formed) on the outer peripheral surface of the core metal, It is the average value of the values measured at any 10 points along the circumferential direction of the prototype. In addition, the JIS-A hardness of the non-foamed cured body of the outer layer 3 is an arbitrary 10 along the circumferential direction of the prototype by producing a prototype consisting of only the non-foamed cured body of the outer layer 3 on the outer peripheral surface of the core metal. It is the average value of the values measured at the location. And the hardness measured from the outer layer 3 side of the elastic layer consisting of the inner layer 2 and the outer layer 3 is along the circumferential direction of the paper feed roller of the present invention (the inner layer 2 is formed with the through hole 4). It is an average value of values measured at arbitrary 10 points.

  Next, materials for forming the hub 1, the inner layer 2 and the outer layer 3 constituting the paper feed roller of the present invention will be described.

  Examples of the material for forming the hub 1 include synthetic resins such as polyacetal (POM), acrylonitrile butadiene styrene copolymer (ABS), polycarbonate, and nylon, and metal materials such as iron, stainless steel, and aluminum.

  The non-foamed cured body of the inner layer 2 is obtained by crosslinking and curing an uncrosslinked thermosetting urethane rubber. Examples of a material for forming the uncrosslinked thermosetting urethane rubber include polypropylene glycol (PPG), poly Those containing each component such as isocyanate, chain extender, plasticizer and the like can be mentioned. The hardness of the non-foamed cured body of the inner layer 2 obtained by crosslinking and curing is adjusted by adjusting the blending ratio of the chain extender and the plasticizer with respect to polypropylene glycol (PPG). For example, when the ASKER-C hardness of the non-foamed cured body of the inner layer 2 is set to the above preferable range (range of 20 to 70 degrees), 4 chain extenders are added to 100 parts by weight of polypropylene glycol (PPG). A weight part and a plasticizer are mix | blended within the range of 50-10 weight part. Further, when the ASKER-C hardness of the non-foamed cured body of the inner layer 2 is set to a more preferable range (range of 30 to 50 degrees), a chain extender is added to 100 parts by weight of polypropylene glycol (PPG). 4 parts by weight and a plasticizer are blended in the range of 35 to 20 parts by weight.

  The non-foamed cured body of the outer layer 3 is also obtained by crosslinking and curing an uncrosslinked thermosetting urethane rubber. Examples of the material for forming the uncrosslinked thermosetting urethane rubber include polyether polyol, polyisocyanate, Examples include those containing each component such as a chain extender and a plasticizer. The polyether polyol is a mixture of polypropylene glycol (PPG) used for forming the inner layer 2 and polytetramethylene ether glycol (PTMG). By mixing the polytetramethylene ether glycol (PTMG), crosslinking is performed. The hardness of the non-foamed cured body of the outer layer 3 obtained by curing can be made higher than that of the inner layer 2. For example, when the JIS-A hardness of the non-foamed cured body of the outer layer 3 is set to the above preferred range (range of 40 to 80 degrees), polytetramethylene ether glycol (PTMG) and polypropylene glycol (PPG) are combined with PTMG. / PPG = mixing at a weight ratio of 99/1 to 50/50. Moreover, when setting the JIS-A hardness of the non-foamed cured body of the outer layer 3 to a more preferable range (range of 50 to 70 degrees), polytetramethylene ether glycol (PTMG) and polypropylene glycol (PPG), Mix in a weight ratio of PTMG / PPG = 90 / 10-60 / 40.

  Next, a method for producing the paper feed roller of the present invention, which is performed using each of the above forming materials, will be described.

  First, a mold for forming the inner layer 2 is prepared. In this mold, a core metal is set coaxially, and a rod-shaped mold for forming the through hole 4 is set around the core metal. Then, an uncrosslinked thermosetting urethane rubber that is a material for forming the inner layer 2 is filled into a molding space excluding the core metal and the rod-shaped mold. Next, it is put in an oven or the like and heated under predetermined conditions. Thereby, the non-foaming hardened | cured material of the thermosetting urethane rubber bridge | crosslinked and hardened in the substantially cylindrical shape is formed in the outer peripheral surface of the said metal core. Then, the core metal and the rod-shaped mold are extracted from the substantially cylindrical non-foamed cured body, and the non-foamed cured body is demolded to obtain the inner layer 2. In this step, the trace of the rod-shaped mold becomes the through hole 4. The heating condition in the formation of the inner layer 2 is that the crosslinking target is a thermosetting urethane rubber, so that the crosslinking temperature can be in the range of 120 to 130 ° C., and the time required for crosslinking is 20 to 40. About a minute. In addition, after the demolding, secondary crosslinking may be performed as necessary. This secondary crosslinking is performed at a temperature lower than the crosslinking temperature (for example, in the range of 100 to 110 ° C.).

  Next, after washing the obtained inner layer 2, a core metal is inserted into the hollow portion of the inner layer 2, and it is set coaxially in a mold for molding the outer layer 3. The molding space between the outer peripheral surface of the inner layer 2 and the inner peripheral surface of the mold is filled with uncrosslinked thermosetting urethane rubber, which is a material for forming the outer layer 3. Next, by putting it in an oven or the like and heating it under predetermined conditions, a non-foamed cured body (outer layer 3) of a thermosetting urethane rubber cross-linked and cured in a cylindrical shape is formed on the outer peripheral surface of the inner layer 2. Is done. And the said core metal is extracted from the cylindrical laminated body which consists of this inner layer 2 and the outer layer 3, and the cylindrical laminated body is demolded. The heating conditions and secondary cross-linking in the formation of the outer layer 3 are the same as those in the formation of the inner layer 2.

  Next, the cylindrical laminated body which consists of the said inner layer 2 and the outer layer 3 is cut | disconnected to predetermined length. Thereafter, the hub 1 of the paper feed roller is press-fitted into the hollow portion of the cylindrical laminate. In this way, the paper feed roller can be obtained. The molding order of the inner layer 2 and the outer layer 3 may be reversed.

  In such a paper feed roller manufacturing method, the inner layer 2 and the outer layer 3 are both formed by crosslinking and curing uncrosslinked thermosetting urethane rubber, and thus can be performed in the same manner. . Moreover, the formation of the inner layer 2 and the outer layer 3 by crosslinking and curing the uncrosslinked thermosetting urethane rubber can be produced with conventional equipment. For these reasons, the paper feed roller of the present invention can be manufactured with reduced costs.

  Furthermore, since both the inner layer 2 and the outer layer 3 are thermosetting urethane rubbers, the inner layer 2 and the outer layer 3 have good compatibility, and the adhesion between the inner layer 2 and the outer layer 3 is strong.

  It should be noted that when the paper feed roller of the present invention is used in a copying machine or the like, the inner layer 2 is bonded to the outer peripheral surface of the hub 1 so that the inner layer 2 does not idle in the circumferential direction on the outer peripheral surface of the hub 1. An agent, a primer, or the like may be applied, or the hub 1 may have a groove formed on the outer peripheral surface thereof along the axial direction. Further, in order to improve the paper feedability of the paper, in the method of manufacturing the paper feed roller, the outer peripheral surface of the outer layer 3 may be polished and roughened after demolding, or the gold for forming the outer layer 3 may be used. A mold whose surface is roughened by electrical discharge machining, chemical etching, shot blasting or the like is used, and the rough surface is transferred to the outer peripheral surface of the outer layer 3 so that the outer peripheral surface of the outer layer 3 is made into a textured surface. It may be formed.

  The paper feed roller of the present invention is suitable as a pick-up roller, a feed roller, a reverse roller, a transport roller, etc. used in office automation equipment such as a copying machine. It can also be used as a feed roller for a money changer, counter, cash dispenser, or the like.

  Next, examples will be described together with comparative examples.

[Preparation of inner layer forming material (uncrosslinked thermosetting urethane rubber)]
100 parts by weight of polypropylene glycol (PPG) [manufactured by Asahi Glass Co., Ltd., PREMINOL S 3005 (monool content: 0.8% by weight, Mn: 5000, number of functional groups: 3, total degree of unsaturation: 0.0048 meq / g)] In contrast, 20 parts by weight of a plasticizer [dibutyl carbitol adipate (Asahi Denka Co., Ltd., Adeka Sizer RS705)], 4 parts by weight of a chain extender [trimethylolpropane (TMP)], 0.01% of a catalyst (DBU-formate) An uncrosslinked thermosetting urethane rubber which is an inner layer forming material was prepared by blending parts by weight and stirring and mixing for 2 minutes under reduced pressure.

[Preparation of outer layer forming material (uncrosslinked thermosetting urethane rubber)]
90 parts by weight of polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG) [manufactured by Asahi Glass Co., Ltd., PREMINOL S 3005 (monool content: 0.8% by weight, Mn: 5000, number of functional groups: 3, total degree of unsaturation) : 0.0048 meq / g)] was vacuum degassed and dehydrated at 80 ° C. for 1 hour, and then mixed with 14 parts by weight of polyisocyanate [tolylene diisocyanate (TDI)], and the mixture was heated to 80 ° C. under a nitrogen atmosphere. For 3 hours to prepare a urethane prepolymer having an NCO group at the end (NCO content: 3.0 wt%, NCO index: 105). The urethane prepolymer was vacuum degassed at 90 ° C. for 30 minutes, then 1.4 parts by weight of a chain extender [1,4-butanediol (1,4-BD)] and a chain extender [trimethylolpropane. (TMP)] 1.2 parts by weight and 0.01 part by weight of catalyst (DBU-formate) are mixed under stirring for 2 minutes under reduced pressure to form an uncrosslinked thermosetting urethane rubber as a material for forming the outer layer. Was prepared.

[Production of paper feed roller]
In the same manner as in the above embodiment, first, a core metal (outer diameter 9 mm) is coaxially set as an inner layer molding die, and 12 rod-shaped molds (outer diameter 6 mm) are disposed around the core metal. ) Are set at equal intervals, and the molding space is filled with the above-mentioned uncrosslinked thermosetting urethane rubber, which is the inner layer forming material, and then the molding die is placed in an oven. Crosslinking was performed at 130 ° C. for 30 minutes. Then, a non-foamed cured body (thickness 9 mm) of a thermosetting urethane rubber cross-linked and cured on the outer peripheral surface of the core metal is obtained, and the core metal and the rod-shaped mold are extracted from the non-foamed cured body and the non-foamed cured body. Was demolded to obtain an inner layer. Next, after washing the inner layer, a cored bar (outer diameter 9 mm) was inserted into the hollow part of the inner layer, and it was set coaxially in the outer layer molding die. Next, the molding space between the outer peripheral surface of the inner layer and the inner peripheral surface of the mold is filled with the uncrosslinked thermosetting urethane rubber as the outer layer forming material, and then the molding die is placed in an oven. And crosslinked at 130 ° C. for 30 minutes. And the non-foaming hardening body (outer layer: thickness 1mm) of the thermosetting urethane rubber bridge | crosslinked and hardened on the outer peripheral surface of the said inner layer was obtained, and the cylindrical laminated body which consists of an inner layer and an outer layer was demolded. Next, the cylindrical laminate was cut to a length of 20 mm, and a cylindrical polyacetal (POM) hub (length: 25 mm, outer diameter: 16 mm) was press-fitted into the hollow portion. In this way, a paper feed roller was obtained.

  In this paper feeding roller, the ASKER-C hardness of the inner layer non-foamed cured body is 70 degrees, the JIS-A hardness of the outer layer non-foamed cured body is 70 degrees, and measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer. The JIS-A hardness (JIS-A hardness of the entire elastic layer) was 5 degrees. The through hole formed in the inner layer had an inner diameter of 6 mm (38% of the hub outer diameter of 16 mm), and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 1.5 mm.

  In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped die for forming the through hole, the through hole formed in the inner layer has an inner diameter of 4 mm (25 mm of the hub outer diameter of 16 mm). %), The shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 1.5 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 25 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

  In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole, the through hole formed in the inner layer has an inner diameter of 2.5 mm (the outer diameter of the hub is 16 mm). 16%), the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 2.25 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 45 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

  In the first embodiment, when the inner layer is formed, the through hole formed in the inner layer has an inner diameter of 5 mm (31 mm with an outer diameter of 16 mm of the hub) by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole. %), The shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 0.5 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 10 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

  In the first embodiment, when the inner layer is formed, the through hole formed in the inner layer has an inner diameter of 3.5 mm (the outer diameter of the hub is 16 mm) by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole. 22%), and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 1.5 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 30 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

  In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole, the through hole formed in the inner layer has an inner diameter of 2.5 mm (the outer diameter of the hub is 16 mm). 16%), the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 3.0 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 40 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

  In Example 1 above, the following materials were used as the inner layer and outer layer forming materials, so that the inner layer non-foamed cured body had an ASKER-C hardness of 20 degrees, and the outer layer non-foamed cured body had a JIS-A hardness of 40. Set to degrees. The through hole formed in the inner layer has an inner diameter of 2.5 mm (16% of the hub outer diameter of 16 mm), and a shortest distance of 0.5 mm between the inner peripheral surface of the through hole and the outer peripheral surface of the hub (the number is Same as Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the whole elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 5 degrees. Other than that, it was the same as in Example 1 above.

[Preparation of inner layer forming material (uncrosslinked thermosetting urethane rubber)]
In Example 1, the plasticizer was changed to 50 parts by weight. Other than that, it was the same as in Example 1 above.

[Preparation of outer layer forming material (uncrosslinked thermosetting urethane rubber)]
In Example 1 above, polytetramethylene ether glycol (PTMG) was changed to 50 parts by weight and polypropylene glycol (PPG) to 50 parts by weight, and a plasticizer [dibutyl carbitol adipate (Adeka Sizer RS705, manufactured by Asahi Denka Co., Ltd.)] Was added to prepare 50 parts by weight. Other than that, it was the same as in Example 1 above.

  In Example 1 above, the following materials were used as the inner layer and outer layer forming materials, whereby the inner layer non-foamed cured body had an ASKER-C hardness of 45 degrees, and the outer layer non-foamed cured body had a JIS-A hardness of 60. Set to degrees. The through hole formed in the inner layer has an inner diameter of 2.5 mm (16% of the hub outer diameter of 16 mm), and a shortest distance of 0.5 mm between the inner peripheral surface of the through hole and the outer peripheral surface of the hub (the number is Same as Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the whole elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 25 degrees. Other than that, it was the same as in Example 1 above.

[Preparation of inner layer forming material (uncrosslinked thermosetting urethane rubber)]
In Example 1, the plasticizer was changed to 30 parts by weight. Other than that, it was the same as in Example 1 above.

[Preparation of outer layer forming material (uncrosslinked thermosetting urethane rubber)]
In Example 1 above, polytetramethylene ether glycol (PTMG) was changed to 70 parts by weight and polypropylene glycol (PPG) to 30 parts by weight, and a plasticizer [dibutyl carbitol adipate (Adeka Sizer RS705, manufactured by Asahi Denka Co., Ltd.)] Was added to prepare 30 parts by weight. Other than that, it was the same as in Example 1 above.

  In Example 1 above, the JIS-A hardness of the non-foamed cured body of the outer layer was set to 80 degrees by using the following as the forming material of the outer layer (for the inner layer forming material and the non-foamed cured body, the above-mentioned The same as in Example 1). The through hole formed in the inner layer has an inner diameter of 6 mm (38% of the outer diameter of the hub of 16 mm), and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub is 0.5 mm Same as 1). Thereby, the JIS-A hardness (JIS-A hardness of the whole elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 45 degrees. Other than that, it was the same as in Example 1 above.

[Preparation of outer layer forming material (uncrosslinked thermosetting urethane rubber)]
In Example 1 above, 99 parts by weight of polytetramethylene ether glycol (PTMG) and 1 part by weight of polypropylene glycol (PPG) were prepared. Other than that, it was the same as in Example 1 above.

[Comparative Example 1]
In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole, the through hole formed in the inner layer has an inner diameter of 7 mm (44 mm of the hub outer diameter of 16 mm). %), The shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 0.5 mm (the number is the same as in Example 1). The JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer could not be measured due to the shape buckling of the inner layer (ASKER of the non-foamed cured body of the inner layer) -C hardness and JIS-A hardness of the non-foamed cured body of the outer layer are the same as in Example 1). Other than that, it was the same as in Example 1 above.

[Comparative Example 2]
In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped die for forming the through hole, the through hole formed in the inner layer has an inner diameter of 1.5 mm (the outer diameter of the hub is 16 mm). 9%), and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 0.5 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 53 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

[Comparative Example 3]
In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped mold for forming the through hole, the through hole formed in the inner layer has an inner diameter of 6 mm (38 mm of the hub outer diameter of 16 mm). %), And the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 0.2 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 45 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above. However, the inner layer portion inside the through hole was torn, and the following wear resistance, friction coefficient maintenance, and heat dissipation could not be evaluated.

[Comparative Example 4]
In the first embodiment, when the inner layer is formed, by changing the outer diameter and arrangement of the rod-shaped die for forming the through hole, the through hole formed in the inner layer has an inner diameter of 3 mm (19 mm of the hub outer diameter of 16 mm). %), The shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub was 4 mm (the number is the same as in Example 1). Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 40 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

[Comparative Example 5]
In Example 1, when the inner layer was formed, a paper feed roller having no through hole formed in the inner layer was produced without using a rod-shaped die for forming a through hole. Thereby, the JIS-A hardness (JIS-A hardness of the entire elastic layer) measured from the outer layer side of the elastic layer composed of the inner layer and the outer layer was set to 55 degrees (ASKER-C hardness of the non-foamed cured body of the inner layer and The JIS-A hardness of the non-foamed cured body of the outer layer is the same as in Example 1). Other than that, it was the same as in Example 1 above.

(Abrasion resistance)
Each of the paper feed rollers of Examples 1 to 9 and Comparative Examples 1 to 5 thus obtained was incorporated into a paper passing durability jig, and 100,000 sheets were passed. Then, the outer diameter of each paper feed roller was measured before being incorporated into the copying machine and after 100,000 sheets were passed, and the wear amount of the outer layer was calculated. As a result, if the outer layer wear amount is less than 50 μm, the wear resistance is extremely excellent, ◎, 50 μm or more and less than 200 μm is excellent in wear resistance, ○, more than 200 μm is inferior in wear resistance, and × It evaluated and it described together with the following Tables 1 and 2. For measuring the outer diameter, a laser outer diameter measuring device (Laser Scan Micrometer, manufactured by Mitutoyo Corporation) was used.

[Friction coefficient maintenance]
Further, the coefficient of friction of the outer peripheral surface of each paper feed roller was measured before being incorporated into the paper passing durability jig and after 100,000 sheets were passed, and the difference was calculated. As a result, when the difference in friction coefficient is 0.1 or less, it is evaluated that the friction coefficient maintenance property is excellent, and when the friction coefficient difference exceeds 0.1, the friction coefficient maintenance property is inferior. This is also shown in Tables 1 and 2.

[Heat dissipation]
Each of the paper feed rollers was used as a separation roller equipped with a torque limiter in an RT (25 ± 3 ° C.) environment, and the surface temperature of each paper feed roller immediately after the continuous 10,000 sheets were measured. As a result, those having a surface temperature of less than 50 ° C. were evaluated as “good” because the heat dissipation was excellent, and those having a surface temperature of 50 ° C. or higher were evaluated as “poor” because they were inferior in heat dissipation.

  From the results of Table 1 above, the paper feed rollers of Examples 1 to 9 are excellent in wear resistance and friction coefficient maintenance and heat dissipation as compared with the paper feed rollers in Comparative Examples 1 to 5. Recognize.

1 is a perspective view schematically showing an embodiment of a paper feed roller of the present invention. It is sectional drawing orthogonal to the axis | shaft of the said paper feeding roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hub 2 Inner layer 3 Outer layer 4 Through-hole A Inner diameter of a through-hole B Outer diameter of a hub C The shortest distance between the inner peripheral surface of a through-hole, and the outer peripheral surface of a hub

Claims (2)

  A paper feed roller comprising a hub and an elastic layer formed on the outer peripheral surface of the hub, wherein the elastic layer is composed of an inner layer and an outer layer, and the inner layer is made of a non-foamed cured body of thermosetting urethane rubber. The outer layer is made of a non-foamed cured body of thermosetting urethane rubber, and has a higher hardness than the non-foamed cured body of the inner layer, and a plurality of through holes extending in the axial direction are formed in the inner layer over the entire circumference. The inner diameter of the through hole is set in a range of 38 to 16% of the outer diameter of the hub, and the shortest distance between the inner peripheral surface of the through hole and the outer peripheral surface of the hub is formed at a predetermined interval. A paper feed roller which is set within a range of 0.5 to 3.0 mm.   The ASKER-C hardness of the non-foamed cured body of the inner layer is set within a range of 20 to 70 degrees, the JIS-A hardness of the non-foamed cured body of the outer layer is set within a range of 40 to 80 degrees, and the through hole The paper feed roller according to claim 1, wherein the JIS-A hardness measured from the outer layer side of the elastic layer composed of the inner layer formed with the outer layer and the outer layer is set in a range of 5 to 45 degrees.

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