JP4570093B2 - Paper feeding / conveying separation roll and manufacturing method thereof - Google Patents

Description

  The present invention relates to a sheet feeding / conveying separation roll mounted on a sheet feeding apparatus such as various printers such as an ink jet printer, various OA devices such as copying machines and facsimile machines, and an automatic teller machine, and a manufacturing method thereof.

  Conventionally, when designing belts and rolls for transporting banknotes, films, magnetic cards, etc. in automatic ticket gates, cash deposit machines, currency exchange machines, etc., consider wear resistance, oil swelling resistance, and environmental dependency. There must be. In addition, a roll for sheet feeding / conveying separation of various OA devices is required to have particularly large conveying force and excellent wear resistance. For these reasons, EPDM (ethylene / propylene / diene rubber) is conventionally used as a roll material having excellent mechanical strength and a high friction coefficient.

  However, with the recent increase in life and speed of OA equipment, EPDM has a problem that satisfactory wear resistance cannot be obtained.

  On the other hand, urethane materials that are excellent in wear resistance have been studied as materials for rolls for paper feed / conveyance separation.

  However, since it is difficult to have a low hardness, there is a problem that the paper feeding performance is inferior. That is, in cast urethane, 50 ° is the limit of low hardness according to JIS A type durometer, and if it is lower than this, it is difficult to use in terms of durability.

  Moreover, the roll which consists of a layer of a foam and a non-foamed layer is proposed (refer patent documents 1-4). However, it is necessary to provide a skin layer on the surface or to bond it, which makes it difficult to manufacture.

Japanese Patent Laid-Open No. 5-80650 (claims) Japanese Patent Laid-Open No. 6-80269 (Claims etc.) Japanese Patent Laid-Open No. 7-266459 (Claims) JP-A-7-285702 (Claims etc.)

  In view of such circumstances, it is an object of the present invention to provide a roll for paper feed conveyance separation having a low hardness, wear resistance, and a stable friction coefficient, and a manufacturing method thereof.

The first aspect of the present invention for solving the above problems is a roll in which at least two layers of rubber-like elastic bodies are formed on the outer periphery of the shaft body, and the outermost layer is made of a cast-type non-foaming polyurethane, wherein Ri inner lining of the outermost layer Do urethane foam closed cell, the outermost layer, which the raw material of the non-foamed polyurethane to the outer periphery of the urethane foam of the closed cell cast was formed by curing It is in the roll for sheet feeding conveyance separation characterized by being.

  According to a second aspect of the present invention, in the first aspect, the surface of the outermost layer is unpolished and has a concavo-convex surface formed by molding.

  According to a third aspect of the present invention, in the first or second aspect, the surface of the inner layer is polished.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the outermost layer has a hardness of 35 to 60 degrees according to JIS A.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the inner layer has a hardness of 10 to 50 degrees in Asker C.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the paper feeding / separation roll has a hardness of 20 to 50 degrees according to JIS A. It is in.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the uneven surface on the surface of the outermost layer is formed with an uneven portion having a corrugated cross section, and the recessed portion is along the axial direction of the roll. The roll for feeding and separating is characterized in that the width of the concave portion is 500 μm or less, the width of the convex portion is 500 μm or less, the height of the convex portion is 50 to 150 μm, and Rz is 40 to 120 μm.

  An eighth aspect of the present invention is a roll manufacturing method in which at least two layers of rubber-like elastic bodies are formed on the outer periphery of a shaft body, and a urethane foam formed by a mechanical floss method is polished into a predetermined roll shape. An inner layer is formed by processing, a shaft is inserted into the inner layer, and a mold is installed outside, and a non-foamed polyurethane is cast and cured between the inner layer and the mold to cure the inner layer. The outermost layer is formed on the outer side.

  ADVANTAGE OF THE INVENTION According to this invention, the roll for paper conveyance separation which has low hardness, is abrasion-resistant, and the friction coefficient was stabilized, and its manufacturing method can be provided.

  Details of the embodiment of the present invention will be described below.

  The roll of the present invention is a roll in which at least two layers of rubber-like elastic bodies are formed on the outer periphery of the shaft body, and the outermost layer is a cast type polyurethane, and the inner layer inside the outermost layer is a closed cell urethane. It consists of a foam. Moreover, the roll should just be the multilayered structure formed from the elastic body of the two layers mentioned above, and of course, it may provide two or more layers by providing a layer under the inner layer. However, the hardness of the roll is 20 to 50 °, preferably 20 to 40 ° according to JIS A. When two or more layers are provided, it is preferable that one layer or two or more layers be provided further on the inner side of the inner layer to enhance the adhesion with the shaft body.

  The urethane foam forming the inner layer of the roll according to the present invention is not particularly limited as long as it is a conventionally known foamed polyurethane. For example, polytetramethylene ether glycol and one or more in the molecular chain A polyol selected from polyols having double bonds (hereinafter sometimes referred to as diene-based polyols) and having a number average molecular weight of 1000 to 4000 and a polyisocyanate compound, and having a trifunctional or higher functionality as a crosslinking agent. Examples thereof include those using a trifunctional polyol having an average molecular weight of 500 to 5000 and a short-chain diol having a number average molecular weight of 80 to 160.

  Here, examples of the polyol having one or more double bonds in the molecular chain include butadiene-based polyols and isoprene-based polyols. Moreover, the polyol obtained by the dehydration condensation of 1,9-nonanediol and 2-methyl-octanediol and a dibasic acid can be mentioned.

  On the other hand, as polyisocyanate to be reacted with polyol, 2,6-toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), 3 , 3-dimethyldiphenyl-4,4′-diisocyanate (TODI). In particular, MDI is preferable in terms of performance and cost.

  Here, examples of the trifunctional polyol having a trifunctional or higher functionality and a number average molecular weight of 500 to 5000 used as a crosslinking agent include ether-based and ester-based polyols.

  On the other hand, the short-chain diol has a number average molecular weight of 80 to 160, and examples thereof include butanediol, pentanediol, hexanediol, and diethylene glycol.

The foaming density (g / cm ³ ) of the urethane foam (cast weight [g] / cast mold volume [cm ³ ]) is, for example, 0.3 to 0.9 [g / cm ³ ]. preferable. If it is less than 0.3, Hs is too low, the cell diameter becomes large and wear resistance decreases, and if it exceeds 0.9, it is close to a solid and affected by paper dust. In addition, when using as a roll for paper feeding conveyance separation, especially a reverse roll, it is preferable to set it as a foaming ratio of 0.3-0.7 (g / cm < ³ >).

  In the case of molding a urethane foam, it may be foam-molded after blending the raw materials at a predetermined ratio, and is molded by mechanical floss that is foamed mechanically by adding a foam stabilizer. Here, the urethane foam is a closed cell. By making the inner layer a closed-cell urethane foam, when casting the outermost layer, there is no risk that the material of the outermost layer will penetrate into the inner layer, and the product hardness of the roll can be easily controlled.

  Further, the rubber hardness (Asker C) of the urethane foam may be appropriately determined according to the use and production conditions, but is preferably 10 to 50 °, more preferably 20 to 40 ° in Asker C. . If the angle is less than 10 °, sufficient mechanical strength cannot be obtained. On the other hand, if the rubber hardness exceeds 50 °, the conveying force is reduced, and a remarkable effect cannot be obtained.

  The surface of the inner layer is polished. By polishing the surface, it is possible to form a roll for paper feed / separation with good dimensional accuracy.

  The outermost layer according to the present invention is made of a cast type urethane, and has a hardness of 35 to 60 °, preferably 40 to 50 ° according to JIS A. By using such a casting type polyurethane, it is possible to obtain a roll for paper feed conveyance separation having excellent wear resistance.

  Here, the casting type liquid polyurethane contains a high molecular weight polyol, an isocyanate compound, a chain extender and a crosslinking agent. Examples of the polyol include polyester polyol, polycarbonate polyol, polyether polyol, and polycarbonate ether polyol. As isocyanate compounds, 4,4′-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), 3,3-dimethyldiphenyl-4-diisocyanate (TODI) ) And paraphenylene diisocyanate (PPDI). Further, it is necessary to use at least a short-chain diol and a short-chain triol as the crosslinking agent. The short-chain diol is not particularly limited, but preferably has at least one of propanediol (PD) and butanediol (BD). Here, 1,3-propanediol is representative as propanediol, and 1,4-butanediol is representative as butanediol, and 1,3-propanediol and 1,4-butanediol are performance and cost. However, the present invention is not limited to this. The short-chain triol is not particularly limited, but preferably has at least one of trimethylolethane (TME) and trimethylolpropane (TMP). Of course, two or more kinds of short-chain diols and short-chain triols may be mixed and used.

  The outermost layer according to the present invention is preferably unpolished and preferably has an uneven surface.

  The uneven surface is not particularly limited as long as it exhibits sheet feeding / conveying separation performance, but it is particularly desirable to have an uneven surface described below.

  FIG. 1 is a schematic perspective view showing an example of a suitable uneven surface of a paper feed / separation roll according to the present invention. As shown in FIG. 1, the feed / separation roll 1 is provided with an inner layer 3 on a cored bar 2, and an outermost layer 4 is provided on the outer periphery of the inner layer 3. In the roll for sheet feeding and conveying separation according to the present invention, an uneven portion having a corrugated cross section is formed on the outer peripheral surface of the elastic layer 3, and the recessed portion 5 forming the uneven portion extends along the axial direction of the roll. ing. That is, the recess is formed by a long groove extending along the axial direction of the roll.

  Here, a preferable uneven surface has an uneven portion with a corrugated cross-section formed on the surface, the recess extends along the axial direction of the roll, the width of the recess is 500 μm or less, the width of the protrusion is 500 μm or less, The height of the part is 50 to 150 μm, and Rz is 40 to 120 μm.

  Here, the “axial direction” includes a direction within about 45 ° with respect to the roll axis. A plurality of the recesses may be provided in the circumferential direction or the axial direction, or a single recess may be provided. When an example of a case where a plurality of recesses are provided on the outer peripheral surface of the roll is schematically illustrated, the outer surface of FIG. It looks like an enlarged view. The hatched portion in FIG. 2 represents a recess. Moreover, the size of each unevenness may be the same size (FIG. 3 (a)) or different sizes (FIG. 3 (b)), as shown in FIG. 3 which is an enlarged sectional view in the roll circumferential direction. ).

  The width of the recess is preferably 500 μm or less. This is because if the width of the concave portion is larger than 500 μm, the distance for conveying the paper is shortened and the paper feeding / conveying performance tends to be poor. As shown in FIG. 3, the width of the concave portion is the distance between the intermediate portions from the top of adjacent convex portions to the bottom of the concave portion formed between the convex portions, that is, the height of the concave and convex portions shown in FIG. The width is based on the average center plane. In addition, the width | variety of a recessed part, the width | variety of a convex part mentioned later, and the height of a convex part can be measured with a general surface roughness measuring machine (Surfcoder SE3500: made by Kosaka Laboratory), for example.

  The width of the convex portion is preferably 500 μm or less. In this case, the concave portion constituting the concavo-convex portion is constituted by a plurality of long grooves arranged at intervals. If the width of the convex portion is larger than 500 μm, it tends to be easily affected by the load, the paper feed speed, and the paper type, and the transport distance tends to be short and the paper feed / conveyance separation performance tends to be inferior. As shown in FIG. 3, the width of the convex portion is the distance between the intermediate portions from the bottom of the adjacent concave portion to the top of the convex portion formed between the concave portions, that is, the height of the concave and convex portions shown in FIG. The width is based on the average center plane.

  Further, when the roll outer peripheral surface is divided by a 1 mm square lattice, it is preferable that each of the divisions has one or more convex portions and concave portions over the entire outer peripheral surface of the roll. It may be a roll having no irregularities at the edges or partially having irregularities.

  The height of the convex part is preferably 50 to 150 μm. If paper dust or the like gets stuck in the recess, paper feeding performance will deteriorate, but if the height of the projection is 50 to 150 μm, paper dust etc. can be trapped in the recess, so paper is repeatedly passed However, the paper feeding performance is not deteriorated and the paper feeding performance is stabilized. In addition, the height of a convex part means the height from the bottom part of a recessed part to the top part of a convex part, as shown in FIG.

  Moreover, it is preferable that both the concave part and the convex part have an axial length that is at least twice as long as the circumferential length. When the length of the concave portion in the axial direction is smaller than twice the circumferential length of the concave portion, the paper powder trapping effect is lowered. Further, when the length of the convex portion in the axial direction is smaller than twice the circumferential length of the convex portion, the contact area between the paper sheet portion and the roll is reduced, and thus the paper feeding characteristics are deteriorated.

  Further, the surface roughness Rz is preferably 40 to 120 μm, more preferably 50 to 80 μm. This is because if the surface roughness is too small, the paper dust trapping effect cannot be obtained, and if it is too large, the paper feed characteristics are not stable.

  As described above, since both the outermost layer and the inner layer are made of polyurethane, a sheet feeding / separating roll having excellent strength can be obtained. In this respect, it is particularly preferable to use polyurethane having the same or similar composition. Furthermore, the outermost layer and the inner layer can be bonded without using an adhesive or the like due to the affinity between the same materials and the anchor effect, and a sheet feeding / separating roll can be easily manufactured. Even if the same material is used, the inner layer is an independent foam, so the outermost layer material does not enter the inner layer, and the product hardness of the roll can be easily controlled.

  With reference to FIG.4 and FIG.5, the manufacturing method of the roll mentioned above is demonstrated. As shown in FIG. 4A, first, the core metal 2 is installed on the central axis of the inner layer manufacturing mold 6. Here, the inner layer manufacturing die 6 and the core metal 2 may be any metal having a certain degree of hardness, and the core metal 2 only needs to have the same outer diameter as the inner diameter of a desired roll. As shown in FIG. 4 (b), the inner layer manufacturing die 6 having the core 2 placed on the central axis is preheated, the raw material of the inner layer 3 is injected by the mechanical floss method, heat-cured, and polished. The inner layer 3 as shown in (c) is obtained. Here, the polishing of the inner layer can improve the dimensional accuracy of the inner layer, whereby the layer of the roll can be manufactured to a uniform thickness, and a roll with good dimensional accuracy can be manufactured.

  Next, as shown in FIG. 5A, the core metal 2 is covered with the inner layer 3 and installed so that the axis center of the outermost layer manufacturing die 8 and the axis center of the core metal 2 coincide. By installing in this way, the cylindrical space 7 is formed. The outermost layer manufacturing die 8 may be a metal having a certain degree of hardness, and the inner diameter of the outermost layer manufacturing die 8 may be substantially equal to the outer diameter of a desired roll. When a surface pattern is applied to the roll, a transfer pattern that is opposite to the surface pattern applied to the roll surface is formed on the inner surface of the outermost layer manufacturing mold 8. The transfer pattern may be formed by an appropriate method such as etching, grinding, or shot blasting.

  Next, as shown in FIG. 5B, the raw material of the outermost layer 4 is injected into a cylindrical space 7 formed between the inner layer 2 and the outermost layer manufacturing mold 8 and heated. Then, when the outermost layer 4 is cured, it is removed from the cored bar 2 and the outermost layer manufacturing mold 8 to obtain a desired paper feed conveyance separation roll as shown in FIG.

  As described above, after the inner layer is cured and polished, the outermost layer is formed, thereby preventing thermal deterioration of the outermost layer that plays a functionally important role.

  Hereinafter, the present invention will be described based on examples.

Example 1
100 parts by weight of polyol O-2010 (manufactured by Kuraray, molecular weight 2000), 15 parts by weight of plasticizer RS107 (manufactured by Asahi Denka), MDI, 6 parts by weight of diethylene glycol (DEG) as a chain extender, and P-3403 (manufactured by Daicel Chemical Industries, molecular weight 4000) was added, mixed at 70 ° C., and further stirred for 3 minutes so as to embed air. A core metal having a diameter of 12 mm was provided at the center of the shaft, and the above-described raw material was cast and cured so that the expansion ratio was 1.3 in an inner layer manufacturing die preheated to 120 ° C. Then, grinding | polishing and parting-off processing were obtained and the urethane foam (inner layer) of inner diameter 12mm, outer diameter 18mm, and length 30mm was obtained. Thereafter, an outermost layer manufacturing die having an inner diameter of 20 mm and having an uneven pattern formed on the inner surface was placed outside the 12 mm core metal covered with the urethane foam. A solution mixed with the urethane foam so as not to embed air was cast and cured to obtain a two-layer feeding / conveying roll.

(Comparative Example 1)
A roll for feeding and separating paper was obtained in the same manner as in Example 1 except that an open-cell foam (inner layer) was formed using silicone.

(Comparative Example 2)
The outermost layer is first manufactured in the same composition as in Example 1, the outermost layer is set in a mold, and then the uncured inner layer is cast and cured in the same manner as in Example 1 to feed and separate the paper. A roll was obtained.

(Comparative Example 3)
A sheet feeding / separating roll was obtained in the same manner as in Example 1 except that the outermost layer in Experimental Example 1 was formed into a single layer with the same composition.

(Comparative Example 4)
A paper feeding / separating roll was obtained in the same manner as in Example 1 except that a single layer was formed from urethane having a hardness of JIS A and 30 ° as a raw material.

(Comparative Example 5)
A paper feeding / separating roll was obtained in the same manner as in Example 1 except that EPDM having a hardness of JIS A and 35 ° was used as a raw material to form a single layer.

(Test Example 1)
With respect to the rolls for sheet feeding and separation formed in Example 1, Comparative Example 1 and Comparative Example 2, the presence or absence of peeling of the upper inner layer and decoloration of the upper layer were visually observed. Further, the outer diameter, the flare, and the product hardness of the sheet feeding / separating roll were measured at 5 and 8 locations, respectively. The results are shown in Table 1.

  In Example 1, separation between the outermost layer and the inner layer did not occur, and variations in dimensional accuracy and product hardness were not observed. On the other hand, in Comparative Example 1, since the outermost layer and the inner layer were not the same material, peeling occurred between the outermost layer and the inner layer. Further, in Comparative Example 2, since the outermost layer was formed first, decolorization occurred due to thermal deterioration, and a significant decrease in dimensional accuracy and a variation in product hardness were observed.

(Test Example 2) Wear resistance evaluation The wear resistance of Example 1 and Comparative Examples 3 to 5 was evaluated at normal temperature and humidity using the durability tester shown in FIG. This endurance tester provides a large speed difference between the roll rotation speed and the sheet moving speed to forcibly generate wear. A free roll 12 is disposed opposite to the paper feed / conveyance separation roll 11 and plain paper (64 g / m ² ) is fed at 20 mm / min from the roll paper 13 in a state where the free roll 12 is pressed with a pressure load of 500 gf. The outer diameter after the paper was fed and the paper feeding / rolling roll 11 was rotated 25000 at 400 rpm was measured, and the rate of change from the outer diameter before the test was measured. The result is shown in FIG.

  As shown in FIG. 7, in Example 1 and Comparative Example 3, it was found that the outer diameter change rate was very small and the wear resistance was good. In contrast, Comparative Examples 4 and 5 were found to have a large outer diameter change rate and low wear resistance.

(Test Example 3) Stability of Friction Coefficient Friction force was measured for each of the sheet feeding and conveying rolls of Example 1 and Comparative Example 3. As shown in FIG. 8, the free roll 12 provided rotatably is brought into pressure contact with each paper feeding / conveying separation roll 11 with a load of 100 gf across the paper 21 and the paper 21 is pulled out at a speed of 50 mm / sec. It was. At this time, the value detected by the load cell 22 attached to one end of the paper 21 becomes the frictional force of each paper feed / conveyance separation roll. The measurement environment was normal temperature and humidity, and the paper type was Ricoh TYPE6200. Measurement was performed when displacements of 0.1 mm and 0.2 mm were generated at the positions shown in FIG. The result is shown in FIG.

  In the roll of Example 1, there was no significant change in the frictional force between the displacement of 0.1 mm and the displacement of 0.2 mm. On the other hand, in the roll of Comparative Example 3, the displacement was 0.2 mm. The frictional force was so great that measurement was impossible.

  As a result, it has been found that the roll of the present invention has excellent wear resistance and a stable friction coefficient.

It is a schematic perspective view showing the image of the roll for sheet feeding conveyance separation concerning the present invention. It is the schematic which shows the state in which the several recessed part was provided in the outer peripheral surface of the roll for sheet feeding conveyance separation of this invention. It is an enlarged view of the cross section of the roll for sheet feeding conveyance separation of this invention. It is a schematic perspective view which shows the manufacturing method of the roll for sheet feeding conveyance separation which concerns on one Embodiment of this invention. It is a schematic perspective view which shows the manufacturing method of the roll for sheet feeding conveyance separation which concerns on one Embodiment of this invention. It is a schematic perspective view which shows an endurance tester. It is a figure which shows the result of Test Example 2. It is a schematic perspective view which shows a friction coefficient measuring apparatus. It is a figure which shows a displacement. It is a figure which shows the result of Test Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Roll for sheet feeding conveyance separation 2 Core metal 3 Inner layer 4 Outermost layer 5 Recessed part 6 Inner layer manufacturing die 7 Cylindrical space 8 Outermost layer manufacturing die 12 Free roll 13 Roll paper 21 Paper 22 Load cell

Claims (8)

A roll in which at least two layers of rubber-like elastic bodies are formed on the outer periphery of a shaft body, and the outermost layer is made of a cast-type non-foaming polyurethane, and the inner layer inside the outermost layer is a closed cell urethane foam. Tona is, the outermost layer, sheet transportation separating roll, characterized in that the material of the non-foamed polyurethane to the outer periphery of the urethane foam of the closed cell cast, and is formed by curing. 2. The sheet feeding / conveying / separating roll according to claim 1, wherein a surface of the outermost layer is unpolished and has an uneven surface formed by molding. The roll for paper feed / separation according to claim 1 or 2, wherein the surface of the inner layer is polished. 4. The paper feeding / separating roll according to claim 1, wherein the outermost layer has a hardness of 35 to 60 [deg.] According to JIS A. 5. The paper feeding / separating roll according to claim 1, wherein the hardness of the inner layer is 10 to 50 degrees in Asker C. 6. The paper feed transport separation roll according to claim 1, wherein the paper feed transport separation roll has a hardness of 20 to 50 degrees according to JIS A. In any one of Claims 1-6, the said uneven surface of the surface of the said outermost layer is formed with the uneven | corrugated | grooved part of a cross-sectional waveform shape, the recessed part is extended along the axial direction of a roll, and the width | variety of a recessed part is 500 micrometers or less. A roll for feeding and separating paper, wherein the width of the convex portion is 500 μm or less, the height of the convex portion is 50 to 150 μm, and Rz is 40 to 120 μm. A method of manufacturing a roll in which at least two layers of a rubber-like elastic body are formed on the outer periphery of a shaft body, wherein an urethane foam formed by a mechanical floss method is polished into a predetermined roll shape to form an inner layer, Inserting a shaft body inside the inner layer and installing a mold outside, casting an unfoamed polyurethane between the inner layer and the mold and curing it to form an outermost layer outside the inner layer A method of manufacturing a roll for separating and feeding paper, which is characterized.

Images