JP2006312293A - Apparatus for producing paper feeding roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus which can produce a high quality paper-feeding roller efficiently and inexpensively. <P>SOLUTION: The apparatus 1 for producing the paper feeding roller, which is shown in Fig. 1, has a mold 2 having a cylindrical cavity 23 and a channel 5 which communicates with the cavity 23 and supplies a molten thermoplastic elastomer into the cavity 23, an injection pin 3 which can move independently of the mold 2, a nozzle 4 supplying the thermoplastic elastomer to the channel 5, and temperature conditioning means 61 and 62 which can condition the temperature of the mold 2. At least one part of each of the mold 2 and the injection pin 3 is preferably constituted of a porous body having a continuous hole formed by adjacent holes communicating with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper feed roller manufacturing apparatus.

Thermoplastic elastomers have weather resistance, rubber elasticity, and can be produced with low hardness. Therefore, thermoplastic elastomers are often used as constituent materials for portions that come into contact with paper in paper feeding roller parts such as OA equipment. In addition, a large number of convex portions are formed on the contact surface so that the paper can be stably conveyed.
A method of forming a paper feeding roller having a complicated shape on the surface in this manner relatively easily by using an injection molding method is disclosed (for example, see Patent Document 1).

However, in the method as described above, when a thermoplastic elastomer is injection-molded, since the filling property at the time of injection molding is low, sink marks are generated when the molded body is solidified, the surface of the molded body is rough, the shape of the complex shape There are various problems such as poor transferability.
In view of this problem, conventionally, additional processing such as correction of sink marks and surface roughness by post-processing, and formation of convex portions after injection molding has been performed.
In addition, the molded body after injection molding is discharged from the mold by the eject pin, but in the molded body composed of a thermoplastic elastomer having a relatively low hardness, molding is performed by applying a high local pressure with the eject pin. The body may be deformed or damaged.

JP-A-9-156784

  An object of the present invention is to provide a paper feed roller manufacturing apparatus capable of efficiently and inexpensively manufacturing a high quality paper feed roller.

The above object is achieved by the following.
The apparatus for manufacturing a paper feed roller according to the present invention is a manufacture of a paper feed roller for producing a paper feed roller having a plurality of minute convex portions on a contact surface with paper by an injection molding method using a thermoplastic elastomer. A device,
A mold having a cavity in which a plurality of concave portions corresponding to the plurality of minute convex portions are formed on an inner surface, and a flow path that communicates with the cavity and supplies the thermoplastic elastomer in a molten state;
Temperature control means for adjusting the temperature of the mold,
Heating means for maintaining the thermoplastic elastomer in the flow path in a molten state.
Thus, a paper feed roller manufacturing apparatus capable of efficiently and inexpensively manufacturing a high quality paper feed roller is obtained.

In the paper feed roller manufacturing apparatus of the present invention, the temperature adjusting means adjusts the temperature of the mold during the injection of the thermoplastic elastomer to a temperature lower by 10 to 150 ° C. than the melting point of the thermoplastic elastomer. Is preferred.
As a result, the flowability (viscosity) of the thermoplastic elastomer is optimized, and the filling property of the thermoplastic elastomer into the cavity is improved, so that a paper feeding roller having better dimensional accuracy and appearance can be obtained. .

In the paper feed roller manufacturing apparatus of the present invention, the temperature adjusting means sets the temperature of the mold during cooling of the thermoplastic elastomer to a temperature lower by 20 to 100 ° C. than the temperature of the mold during injection. It is preferable to adjust.
Thereby, the paper feeding roller which has the more outstanding dimensional accuracy and external appearance can be obtained by solidifying the thermoplastic elastomer in a cavity, suppressing a sink or a deformation | transformation. In addition, the releasability of the paper feed roller with respect to the cavity is improved, and the paper feed roller can be released more easily by the eject pin.

In the paper feed roller manufacturing apparatus of the present invention, the inner surface preferably has a surface roughness Ra (specified in JIS B 0601) of 5 to 200 μm.
Thereby, a convex portion is formed on the surface of the paper feeding roller, and the paper feeding roller can press the paper with a necessary and sufficient pressing force by the convex portion, so that the paper feeding roller slips, It is possible to suppress or prevent the paper feeding roller from being deformed due to application of a pressing force more than necessary.

In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the concave portion is formed by at least one method of blast, transfer, and vibration cutting.
Thereby, the recessed part of a desired shape can be formed efficiently and easily.
In the paper feed roller manufacturing apparatus according to the present invention, the molding die includes an eject pin for detaching the molded paper feed roller from the molding die, and an end surface of the eject pin constitutes a part of the inner surface. It is preferable.
Thereby, the paper feed roller can be detached from the mold.

In the paper feed roller manufacturing apparatus according to the present invention, it is preferable that the cavity has a cylindrical shape, and the flow path opens at one end face of the cylindrical shape of the cavity.
Thereby, it can prevent that the solid substance of a thermoplastic elastomer will be formed in the contact surface (side surface) with the paper of the cylindrical paper feeding roller.
In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the cavity has a cylindrical shape, and the flow path is open to a side surface of the cylindrical cavity.
Thereby, a solid body of thermoplastic elastomer is formed on the side surface of the cylindrical paper feeding roller, and this solid body is one of a plurality of minute convex portions intentionally formed on the side surface. As a result, it contributes to the stable conveyance of paper.

In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the cavity has a cylindrical shape, and an end surface of the eject pin constitutes one end surface of the cylindrical cavity.
As a result, the end face of the eject pin can uniformly press the entire end face of the paper feed roller, so that deformation of the paper feed roller due to the pressing force can be minimized.

The paper feed roller manufacturing apparatus of the present invention is configured such that the eject pin can be moved in a direction to reduce the volume of the cavity before the thermoplastic elastomer is solidified in the cavity. Is preferred.
As a result, the thermoplastic elastomer before being solidified is further compressed to increase the density of the paper feeding roller, and a high-quality paper feeding roller with high density and reduced sink marks and deformation can be obtained.

In the paper feed roller manufacturing apparatus of the present invention, the eject pin is composed of a porous body having at least part of continuous pores in which adjacent pores communicate with each other,
It is preferable that the gas in the cavity is discharged to the outside of the cavity through the continuous holes.
Thereby, when the thermoplastic elastomer is injected into the cavity, the residual gas in the cavity can be efficiently discharged to the outside of the cavity through the continuous holes. As a result, it is possible to more reliably prevent the residual gas from being taken into the formed paper feed roller and causing a defect (such as a void).

In the paper feed roller manufacturing apparatus of the present invention, at least a part of the mold is composed of a porous body having continuous pores in which adjacent pores communicate with each other,
It is preferable that the gas in the cavity is discharged to the outside of the cavity through the continuous holes.
Thereby, when the thermoplastic elastomer is injected into the cavity, the residual gas in the cavity can be efficiently discharged to the outside of the cavity through the continuous holes. As a result, it is possible to more reliably prevent the residual gas from being taken into the formed paper feed roller and causing a defect (such as a void).

In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the pressure when supplying the thermoplastic elastomer into the cavity is 5 to 150 MPa.
Thereby, the filling property of the thermoplastic elastomer into the cavity is improved, and the obtained paper feeding roller has better dimensional accuracy and appearance.
In the paper feed roller manufacturing apparatus of the present invention, the thermoplastic elastomer preferably has a Shore A hardness of 10 to 40 °.
Thereby, the stability of paper feeding of the paper feeding roller can be improved most, and the moldability (ease of molding) and filling property of the paper feeding roller can be improved.

In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the paper feed roller manufacturing apparatus has a pressure reducing means for decompressing the inside of the cavity.
Thereby, the inside of a cavity can be exhausted and pressure-reduced via the piping, exhaust path, and small diameter exhaust path which mutually communicate. As a result, when the thermoplastic elastomer is injected into the cavity, it is possible to improve the quality and appearance of the paper feed roller by preventing the residual gas in the cavity from being taken into the thermoplastic elastomer and causing defects. .

In the paper feed roller manufacturing apparatus of the present invention, the molding die is provided with a mounting portion for mounting the shaft of the paper feeding roller, and the shaft is mounted on the mounting portion as an inner material for inner molding. In this state, it is preferable that the thermoplastic elastomer is configured to be subjected to inner molding.
As a result, when obtaining a paper feeding roller assembly in which the shaft is inserted into the through hole of the paper feeding roller, the shaft can be penetrated simultaneously with the manufacture of the paper feeding roller. The trouble of doing can be omitted.

In the paper feed roller manufacturing apparatus of the present invention, it is preferable that the paper feed roller manufacturing apparatus has a second mold for molding the shaft.
As a result, the shaft and the paper feed roller can be manufactured in a series of manufacturing processes, so that the trouble of penetrating the shaft into the through hole can be omitted, and the cost required for manufacturing or preparing the shaft can be reduced. can do.

Hereinafter, a paper feed roller manufacturing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
<First Embodiment>
First, a first embodiment of a paper feed roller manufacturing apparatus according to the present invention will be described.
FIG. 1 is a schematic view (longitudinal sectional view) showing a closed state of a first embodiment of a paper feeding roller manufacturing apparatus, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a paper shown in FIG. It is a perspective view of the paper feed roller manufactured with the manufacturing apparatus of the feed roller.

  A paper feeding roller manufacturing apparatus 1 shown in FIG. 1 includes a mold 2 having a cylindrical cavity 23 and a flow path 5 that communicates with the cavity 23 and supplies a molten thermoplastic elastomer to the cavity 23. The ejector pin 3 is movable independently of the mold 2, the nozzle 4 supplies a thermoplastic elastomer to the flow path 5, and temperature control means 61 and 62 that can adjust the temperature of the mold 2.

  The paper feeding roller manufacturing apparatus 1 according to the present invention is an injection molding apparatus that obtains a paper feeding roller 10 by filling a cavity 23 with a thermoplastic elastomer. That is, by feeding a thermoplastic elastomer (molding material) into the cavity 23 via the nozzle 4 and the flow path (runner) 5, the paper feed as shown in FIG. The roller 10 is configured to be molded.

Hereinafter, each part will be described in detail.
The mold 2 has a pair of a movable mold 21 and a fixed mold 22.
Among these, the movable die 21 is movable to the left and right, and has two cylindrical shapes that have a cavity 211 inside and open at the contact surface 212 with the fixed die 22 as shown in FIG. It has a cavity 23, two core molds 213 that pass through both end faces of each cavity 23, and temperature adjusting means 61 that can adjust the temperature of the movable mold 21. In addition, an eject pin 3 is provided inside the movable die 21, and one end surface 31 thereof constitutes the inner surface of the cavity 23. Further, outside the movable mold 21, the movable mold 21 and the fixed mold 22 are separated from the movable mold 21 and the fixed mold 22 shown in FIG. A moving means (not shown) for moving the movable mold 21 is provided so as to shift to the open state.

On the other hand, as shown in FIG. 1, the fixed mold 22 has a cavity 221 inside thereof, and temperature adjusting means 62 that can adjust the temperature of the fixed mold 22. Further, adjacent to the inside and outside of the fixed mold 22, a flow path 5 having one open end on the contact surface 222 with the movable mold 21 and a nozzle 4 communicating with the other open end of the flow path 5 are provided. ing.
Further, the mold 2 defines a cylindrical cavity 23 surrounded by both the molds 21 and 22 and the eject pin 3 when the contact surfaces 212 and 222 shown in FIG. At the same time, one open end (gate) of the flow path 5 is configured to be located at a portion corresponding to the end surface of the cavity 23 of the contact surface 222.

  The constituent material of the mold 2 is not particularly limited as long as it has characteristics as a mold, and for example, various metal materials and various ceramic materials can be used. Among these, the constituent material is preferably a metal material. The metal material has a high thermal conductivity, whereby the thermal conductivity of the mold 2 is improved, and the temperature adjustment by the temperature adjusting means 61 and 62 can be performed more accurately and quickly. As a result, the obtained paper feed roller 10 has better dimensional accuracy and appearance.

  Moreover, it is preferable that the shaping | molding die 2 is comprised with the porous body which has the continuous void | hole from which the adjacent void | hole communicates at least one part. Thereby, as will be described later, when the thermoplastic elastomer is injected into the cavity 23, the residual gas in the cavity 23 can be efficiently discharged to the outside of the cavity 23 through the continuous holes. As a result, it is possible to more reliably prevent the residual gas from being taken into the molded paper feeding roller 10 and causing defects (voids or the like). Specific examples of such a porous body include, for example, porous metals (porous metals), porous ceramics (porous ceramics), and the like. In addition, the inner diameter of the pores of the porous body is not particularly limited as long as the pores are continuous pores, but is preferably about 10 to 100 μm, and more preferably about 20 to 50 μm.

The cavity 23 is a cylindrical cavity defined by the molds 21 and 22 and the eject pin 3 when the molds 21 and 22 are closed.
By filling the cavity 23 with a thermoplastic elastomer, the paper feeding roller 10 that matches the shape of the cavity 23 can be formed. By providing a desired shape on the inner surface of the cavity 23, the paper feed roller 10 having a shape corresponding to the shape can be obtained.
Conventionally, since the thermoplastic elastomer has low filling property at the time of injection molding, even if a complicated shape is formed on the inner surface of the cavity, it is difficult to transfer the shape to the molded body with high dimensional accuracy. For this reason, it is generally difficult to form a plurality of convex portions (textures) provided on the contact surface of the paper feed roller with the paper by an injection molding method.

The present inventor has completed the paper feeding roller manufacturing apparatus 1 of the present invention in order to solve such problems.
That is, by using the paper feeding roller manufacturing apparatus 1 of the present invention, a plurality of minute convex portions formed corresponding to the plurality of concave portions provided on the inner surface of the cavity 23 are provided on the contact surface with the paper. The paper feed roller 10 can be efficiently manufactured with high dimensional accuracy.

  The inner surface of the cavity 23 has a surface roughness Ra (as defined in JIS B 0601) of preferably about 5 to 200 μm, more preferably about 10 to 150 μm. That the surface roughness Ra of the inner surface of the cavity 23 is within the above range indicates that there is a concave portion having the same depth on the inner surface of the cavity 23. The concave portion is formed as a convex portion having the same height on the surface of the paper feed roller 10 as the paper feed roller 10 is injection molded. As a result, the paper feeding roller 10 can press the paper with a necessary and sufficient pressing force by this minute convex portion, and therefore the paper feeding roller 10 slips or imparts an excessive pressing force. Further, it is possible to suppress or prevent the paper feeding roller 10 from being deformed. That is, it is possible to obtain the paper feeding roller 10 that can stably convey the paper.

By the way, the concave portion formed on the inner surface of the cavity 23 may be formed by any method. For example, blast, transfer, vibration cutting, machining, milling, laser processing, water jet processing, etc. It can be formed using electric discharge machining or the like. Of these, blasting, transfer, and vibration cutting are preferably used. Thereby, the recessed part of a desired shape can be formed efficiently and easily.
At this time, the concave portion having a desired shape may be formed by various surface processing such as satin, wave pattern, lattice, emboss, silk pattern, vertical line, horizontal line, and the like.

An eject pin 3 is provided in the movable die 21 shown in FIG.
One end surface 31 of the eject pin 3 constitutes a part of the inner surface of the cavity 23, and after forming the paper feed roller (molded body) 10, when the mold 2 is in the mold open state, By moving independently and being inserted into the cavity 23, the paper feeding roller 10 is detached from the mold 2. Further, the other end portion of the eject pin 3 extends to a moving means 32 provided outside the movable die 21, whereby the eject pin 3 is movable in a manner that it can be inserted into and removed from the cavity 23. .

  Since one end surface 31 of the eject pin 3 constitutes a part of the inner surface of the cavity 23, the eject pin 3 does not have a small area in which the paper feeding roller 10 is pressed (pressed area) in a point-like manner. The paper feeding roller 10 can be pressed by the planar end face 31 having a larger pressing area to be detached from the mold 2. Thereby, the pressing force that the eject pin 3 applies to the paper feed roller 10 can be dispersed without being concentrated locally. As a result, deformation of the paper feed roller 10 due to the pressing force can be prevented more reliably.

  The shape of the eject pin 3 is not particularly limited as long as the paper feeding roller 10 can be detached from the mold 2, but when the cavity 23 has a cylindrical shape, the end surface 31 has the cylindrical shape. It is preferable to constitute one end face. As a result, the end surface 31 can uniformly press the entire end surface of the paper feed roller 10, so that deformation of the paper feed roller 10 due to the pressing force can be suppressed to a minimum.

  Furthermore, in this case, it is preferable that the eject pin 3 can be moved in a direction to reduce the volume of the cavity 23 before the cavity 23 is filled with the thermoplastic elastomer and the thermoplastic elastomer is solidified. As a result, the thermoplastic elastomer before being solidified is further compressed to increase the density of the paper feed roller 10 and to obtain a high-quality paper feed roller 10 with higher density and reduced sink marks and deformation. .

Further, like the mold 2, at least a part of the eject pin 3 is preferably composed of a porous body having continuous pores in which adjacent pores communicate with each other. Thereby, as will be described later, when the thermoplastic elastomer is injected into the cavity 23, the residual gas in the cavity 23 can be efficiently discharged to the outside of the cavity 23 through the continuous holes. As a result, it is possible to more reliably prevent the residual gas from being taken into the molded paper feeding roller 10 and causing defects (voids or the like). Specific examples of such a porous body include, for example, porous metals (porous metals), porous ceramics (porous ceramics), and the like. In addition, the inner diameter of the pores of the porous body is not particularly limited as long as the pores are continuous pores, but is preferably about 10 to 100 μm, and more preferably about 20 to 50 μm.
As shown in FIG. 1, the nozzle 4 is provided adjacent to the fixed mold 22 on the side opposite to the movable mold 21.

The nozzle 4 communicates with the flow path 5 and supplies molten thermoplastic elastomer to the flow path (runner) 5 at a high pressure.
On the side opposite to the flow path 5 of the nozzle 4, there is an injection means (not shown). The injection means interlocks with the moving means for moving the moving mold 21 and, when the mold 2 is in the closed state, causes the molten thermoplastic elastomer to enter the cavity 23 through the nozzle 4 and the flow path 5 at a high pressure. To supply.

The flow path 5 is provided inside the fixed mold 22 and serves as a flow path for supplying (injecting) the thermoplastic elastomer supplied from the nozzle 4 to the cavity 23 at a high pressure.
Moreover, the flow path 5 is provided with a heating means 51 for heating the thermoplastic elastomer in the flow path 5 so that the molten state of the thermoplastic elastomer can be maintained and can be circulated without delay. As a result, wasteful consumption of the thermoplastic elastomer can be suppressed, and the manufacturing cost of the paper feed roller can be reduced.

  The pressure when supplying the thermoplastic elastomer from the flow path 5 into the cavity 23 is slightly different depending on the fluidity (viscosity) of the thermoplastic elastomer, but is preferably about 5 to 150 MPa, and about 5 to 100 MPa. More preferably. By setting the pressure within the above range, the filling property of the thermoplastic elastomer into the cavity 23 is improved, and the obtained paper feeding roller 10 has more excellent dimensional accuracy and appearance.

  Further, as described above, one open end of the flow path 5 is configured to be located at a portion corresponding to the end face of the cylindrical cavity 23. With such a configuration, the solid matter may be very small on the end surface of the cylindrical paper feeding roller 10, but even in that case, There is no possibility of adversely affecting the dimension of the side surface that is the contact surface with the paper. Therefore, it is possible to obtain a high-quality paper feed roller 10 having excellent paper conveyance performance.

  The constituent material of the nozzle 4 and the flow path 5 is not particularly limited as long as it has durability against the thermoplastic elastomer in a molten state. For example, various metal materials and various ceramic materials are used. be able to. Among these, the constituent material is preferably a metal material. The metal material has a high thermal conductivity, and by using this, the thermal conductivity of the nozzle 4 and the channel 5 can be improved, and the temperature of the nozzle 4 and the channel 5 can be adjusted more accurately and quickly. As a result, the thermoplastic elastomer in the nozzle 4 and the flow path 5 can be maintained in a molten state, and the viscosity thereof can be maintained more stably. The resulting paper feed roller 10 has superior dimensional accuracy and It will have an appearance.

The temperature adjusting means 61 is provided in the movable mold 21 and adjusts the temperature of the movable mold 21, and the temperature adjusting means 62 is provided in the fixed mold 22 and adjusts the temperature of the fixed mold 22.
By adjusting the temperature of the mold 2 using these temperature control means 61 and 62, the temperature of the thermoplastic elastomer filled in the cavity 23 is adjusted, and the degree of melting or solidification of the thermoplastic elastomer is adjusted. can do. As a result, it is possible to optimize the molding of the plurality of convex portions formed on the surface of the paper feed roller 10 and obtain the paper feed roller 10 having better dimensional accuracy and appearance.

  Further, the temperature adjusting means 61 and 62 can adjust the temperature of the mold 2 to 10 to 150 ° C. lower than the melting point of the thermoplastic elastomer to be used when the thermoplastic elastomer is injected into the cavity 23. preferable. By adjusting the temperature of the mold 2 within the above range, the flowability (viscosity) of the thermoplastic elastomer is optimized, and the filling property of the thermoplastic elastomer into the cavity 23 is improved. In addition, the paper feeding roller 10 having an appearance can be obtained.

  Further, the temperature adjusting means 61, 62, when cooling and solidifying the thermoplastic elastomer injected into the cavity 23, sets the temperature of the mold 2 to 20-100 from the temperature of the mold 2 at the time of injection. It is preferable that the temperature can be adjusted to a lower temperature. Thereby, the paper-feeding roller 10 having better dimensional accuracy and appearance can be obtained by solidifying the thermoplastic elastomer in the cavity 23 while suppressing sink marks and deformation. In addition, the releasability of the paper feed roller 10 with respect to the cavity 23 is improved, and the paper feed roller 10 can be released more easily by the eject pin 3.

As a specific example of such temperature control means 61 and 62, for example, a heat exchanger is provided inside or outside the mold 2 and a working fluid (water, oil, etc.) having a predetermined temperature is supplied to the heat exchanger. Thus, a method for adjusting the temperature of the mold 2, winding a conductive wire around the mold 2, and applying an alternating current of a predetermined voltage / current to the conductive wire, heat due to loss of induced current generated in the mold 2 Examples include a method of adjusting the temperature of the mold 2 using energy.
Further, the paper feeding roller manufacturing apparatus 1 includes a decompression unit 7 that decompresses the inside of the cavity 23.

  The decompression means 7 shown in FIG. 1 includes an exhaust pump 71, a pipe 72 that connects the exhaust pump 71 and the cavity 23 in an airtight manner, an exhaust path 73, and a small-diameter exhaust path 74. The exhaust pump 71 can exhaust and depressurize the cavity 23 through the pipe 72, the exhaust path 73, and the small-diameter exhaust path 74 that communicate with each other. As a result, when the thermoplastic elastomer is injected into the cavity 23, the residual gas in the cavity 23 is prevented from being taken into the thermoplastic elastomer to cause defects, and the quality and appearance of the paper feed roller 10 are improved. be able to.

The decompression means 7 has an exhaust pump 71, a pipe 72 that communicates with each other, an exhaust path 73, and a small-diameter exhaust path 74. These are connected in order of the pipe 72, the exhaust path 73, and the small diameter exhaust path 74 from the exhaust pump 71 side, and the end of the small diameter exhaust path 74 opposite to the exhaust pump 71 opens into the cavity 23. .
The exhaust pump 71 can be configured by, for example, a rotary pump, a dry pump, a turbo molecular pump, or the like.

The pipe 72 is not particularly limited as long as it maintains airtightness and connects the exhaust pump 71 and the exhaust path 73, but is preferably flexible. Thereby, when the movable mold | type 21 moves, it can prevent that remarkable load is added to the connection part of the piping 72 because the piping 72 bends.
The exhaust path 73 is provided in the movable mold 21 and connects the pipe 72 and the small-diameter exhaust path 74. The inner diameter of the exhaust path 73 is preferably as large as possible. Thereby, exhaust can be performed efficiently.

The small-diameter exhaust path 74 connects the exhaust path 73 and the cavity 23. The small-diameter exhaust passage 74 has an extremely small inner diameter. Thereby, it is possible to more reliably prevent the thermoplastic elastomer supplied to the cavity 23 from leaking out of the cavity 23.
At this time, the inner diameter of the small-diameter exhaust passage 74 varies slightly depending on the viscosity of the thermoplastic elastomer, but is preferably about 10 to 100 μm, and more preferably about 20 to 50 μm. Thereby, leaking out of the thermoplastic elastomer can be more reliably prevented while the pressure inside the cavity 23 is reliably reduced. As a result, it is possible to more reliably prevent burrs of the paper feed roller 10 caused by leakage.

Hereinafter, an example of a method (action) of using the paper feeding roller manufacturing apparatus 1 as described above will be described.
[1] First, as shown in FIG. 1, the mold 2 is put into a closed state. Further, the eject pin 3 is moved by the moving means 32 so that the cavity 23 has a predetermined volume.
[2] Next, the exhaust pump 71 is activated to exhaust the gas in the cavity 23 to reduce the pressure in the cavity 23.
Although it does not specifically limit as a pressure after pressure reduction in the cavity 23, It is preferable that it is about 0.01-0.1 MPa, and it is more preferable that it is about 0.01-0.05 MPa. The pressure may be lower than the above range, but it is not expected to further improve the filling property of the thermoplastic elastomer.

[3] Next, the flow path 5 is heated by the heating means 51.
The temperature at the time of heating is appropriately set according to the melting point of the thermoplastic elastomer used for the paper feed roller 10 to be manufactured, but is preferably set to a temperature at which the thermoplastic elastomer is in a molten state.
[4] Next, prior to molding of the thermoplastic elastomer, the temperatures of the movable mold 21 and the fixed mold 22 are adjusted by the temperature adjusting means 61 and 62. Thereby, the fluidity (viscosity) of the thermoplastic elastomer is optimized, and the filling property into the cavity 23 is improved.
The temperature is appropriately set depending on the composition of the thermoplastic elastomer to be used, fluidity (viscosity), and the like, but as described above, it is preferably adjusted to a temperature lower by 10 to 150 ° C. than the melting point of the thermoplastic elastomer to be used.

[5] Next, the molten thermoplastic elastomer is supplied into the cavity 23 from the injection means and the nozzle 4 through the flow path 5 at a high pressure and filled.
The pressure at which the thermoplastic elastomer is supplied varies depending on the fluidity (viscosity) of the thermoplastic elastomer, but is adjusted within the above range.
Although it does not specifically limit as a thermoplastic elastomer, For example, a styrene-type thermoplastic elastomer, a polyolefin-type thermoplastic elastomer, a polyester-type thermoplastic elastomer, a polyvinyl chloride-type thermoplastic elastomer, a polyurethane-type thermoplastic elastomer, a polyamide-type thermoplastic elastomer A combination of one or two or more of polybutadiene-based thermoplastic elastomer, polyisoprene-based thermoplastic elastomer, nitrile-based thermoplastic elastomer, and the like is preferably used.
Moreover, as a thermoplastic elastomer, it is preferable that the Shore A hardness is 10-40 degrees, and it is more preferable that it is 15-35 degrees. Thereby, the stability of paper feeding of the paper feeding roller 10 can be most improved, and the moldability (ease of molding) and the filling property of the paper feeding roller 10 can be improved.

  [6] Next, the eject pin 3 is moved by the moving means 32 in the direction of decreasing the volume of the cavity 23. Thereby, the thermoplastic elastomer before solidification can be further compressed to increase the density, and the paper feeding roller 10 with high dimensional accuracy and less deformation (sink mark etc.) after molding can be obtained. In addition, by performing such compression molding, the transfer property to the paper feeding roller 10 having the shape of the concave portion provided on the inner surface of the cavity 23 becomes more excellent.

[7] Next, in order to solidify the thermoplastic elastomer, each temperature of the movable mold 21 and the fixed mold 22 is adjusted by the temperature adjusting means 61 and 62. Thereby, the thermoplastic elastomer can be solidified while suppressing sink marks and deformation, and the paper feeding roller 10 can be obtained.
As described above, the temperature is preferably adjusted to a temperature lower by 20 to 100 ° C. than the temperature of the step [5].

[8] Next, the exhaust pump 71 is stopped, the pressure reducing means 7 is disabled, and the movable die 21 is moved to the opposite side of the fixed die 22 to bring the molding die 2 into the mold open state.
[9] Next, the ejecting pin 3 is moved to the fixed mold 22 side by the moving means 32 and the paper feed roller 10 in the cavity 23 is discharged.
As described above, the cylindrical paper feeding roller 10 having the through holes 12 as shown in FIG. 3A can be obtained.

If necessary, after the step [9], one columnar shaft 11 is inserted into each through hole 12 of one or two or more paper feed rollers 10, and FIG. A paper feeding roller assembly 10 ′ as shown in FIG.
The shaft 11 is provided with a rotational torque when the paper feeding roller assembly 10 ′ is rotated, and becomes a rotational shaft.

Second Embodiment
Next, a second embodiment of the paper feed roller manufacturing apparatus of the present invention will be described.
FIG. 4 is a schematic view (longitudinal sectional view) showing a mold closing state of the second embodiment of the paper feed roller manufacturing apparatus.
Hereinafter, the paper feed roller manufacturing apparatus according to the second embodiment will be described. The difference from the paper feed roller manufacturing apparatus according to the first embodiment will be mainly described, and the same matters will be described. Is omitted.

  As shown in FIG. 4, the paper feed roller manufacturing apparatus 1 according to the second embodiment is mounted so that the shaft 11 of the paper feed roller 10 is positioned so as to be located approximately in the middle of the movable die 21 and the fixed die 22. A portion 24 is provided in the movable die 21 and the fixed die 22, and a cavity 23 is formed so as to cover a part of the shaft 11 with the shaft 11 as a center. The shaft 11 is attached to the mounting portion 24 as an inner material. In this state, the apparatus is the same as the paper feed roller manufacturing apparatus 1 of the first embodiment except that the inner molding of the thermoplastic elastomer is performed.

  When the shaft 11 is inserted into the through-hole 12 of the cylindrical paper feed roller 10, in the first embodiment, it is performed after the paper feed roller 10 is manufactured. Since it can be performed at the same time as the manufacturing, the trouble of penetrating the shaft 11 into the through hole 12 can be omitted. As a result, the paper feed roller manufacturing apparatus 1 capable of more efficiently manufacturing the paper feed roller assembly 10 'is obtained.

In the second embodiment, one open end of the flow path 5 is configured to be located at a portion corresponding to the side surface of the cylindrical cavity 23. With such a configuration, a small amount of the solid matter generated in the vicinity of the opening end may be generated on the side surface of the cylindrical paper feeding roller 10, that is, the contact surface with the paper. Even in this case, the solid matter contributes to the stable conveyance of the paper as one of a plurality of minute convex portions (textures) intentionally formed on the side surface.
When using the paper feed roller manufacturing apparatus 1 of the second embodiment, the columnar shaft 11 is mounted on the mounting portion 24 prior to the step [1], and then the mold 2 is closed. And

<Third Embodiment>
Next, a third embodiment of the paper feed roller manufacturing apparatus of the present invention will be described.
FIG. 5 is a schematic view (longitudinal sectional view) showing a mold closing state of the third embodiment of the paper feed roller manufacturing apparatus.
Hereinafter, the paper feeding roller manufacturing apparatus according to the third embodiment will be described. However, the difference from the paper feeding roller manufacturing apparatus according to the first and second embodiments will be mainly described, and similar matters will be described. The description is omitted.

  As shown in FIG. 5, the paper feeding roller manufacturing apparatus 1 according to the third embodiment supplies a second cavity 25 for molding the shaft 11 and a molding material of the shaft 11 to the second cavity 25. A second flow path 52, a second nozzle 41 for supplying the molding material to the second flow path 52, a second heating means 53 for heating the molding material in the second flow path 52, and paper The apparatus for manufacturing a paper feed roller according to the second embodiment, except that the feed roller 10 is fitted in a space corresponding to a cavity for molding and has a core 26 constituting a part of a mold of the shaft 11. Same as 1.

In the third embodiment, the shaft 11 and the paper feed roller 10 can be manufactured in a series of manufacturing steps prior to the formation of the paper feed roller 10, so that the trouble of penetrating the shaft 11 into the through hole 12 can be reduced. Further, the cost required for manufacturing or preparing the shaft 11 can be reduced. As a result, the paper feed roller manufacturing apparatus 1 that can manufacture the paper feed roller assembly 10 'more efficiently and inexpensively is obtained.
The second cavity 25 is a columnar cavity defined by the movable mold 21, the fixed mold 22, and the core 26 in the closed state.

FIG. 6 is a diagram (perspective view) showing the core 26 mounted on the paper feed roller manufacturing apparatus 1 according to the third embodiment.
The core 26 has a shape in which the paper feeding roller 10 is divided into two along the central axis. The core 26 is mounted in a space to be filled with a thermoplastic elastomer, and prevents the space from being filled with the constituent material of the shaft 11 when the shaft 11 is molded.

Here, a method of using the paper feeding roller manufacturing apparatus 1 according to the third embodiment will be described.
In the present embodiment, the second cavity 25 is filled with the molding material of the shaft 11 from the nozzle 41 through the flow path 52 in a state where the core 26 is mounted, thereby matching the shape of the second cavity 25. The shaft 11 can be formed. At this time, a desired shape can be formed on the surface of the shaft 11 by providing a desired shape on the inner surface of the second cavity 25.

  Next, after the shaft 11 is molded, the mold 2 is opened and the core 26 is removed. Then, in the mold closed state again, the space (cavity 23) from which the core 26 has been removed is filled with the thermoplastic elastomer from the nozzle 4 through the flow path 5, whereby the paper feed roller 10 that matches the shape of the cavity 23. Can be formed. As a result, the paper feeding roller assembly 10 ′ having the shaft 11 and the paper feeding roller 10 can be manufactured more efficiently and inexpensively.

In the third embodiment, it is particularly preferable to use various resin materials as the molding material of the shaft 11. The resin material can be easily formed by the injection molding method as described above.
The resin material is preferably a resin material that requires a higher melting point than that of the thermoplastic elastomer used as the constituent material of the paper feed roller 10. Thereby, when the shaft 11 is exposed to the molten thermoplastic elastomer, deformation due to melting or softening can be prevented.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to this.
For example, each part constituting the paper feed roller manufacturing apparatus of the present invention can be replaced with an arbitrary one that exhibits the same function, or another configuration can be added.
In each of the above-described embodiments, the paper feeding roller manufacturing apparatus is described based on a configuration having cavities for two paper feeding rollers. However, the present invention is not limited to this, and three or more cavities are used. You may have. Further, the nozzle may be omitted by extending the flow path, and the thermoplastic elastomer may be directly supplied to the flow path from the injection means.

Next, specific examples of the present invention will be described.
1. Production of paper feed roller (Example)
The paper feed roller 10 shown in FIG. 3 was produced using the paper feed roller manufacturing apparatus having the structure shown in FIG. The conditions at the time of production are shown below.

Mold component material: Porous stainless steel Temperature of heating means of channel: 200 ° C
Mold temperature during injection: 100 ° C
Mold temperature during cooling: 30 ° C
Cavity shape: Cylindrical (diameter 10 mm x length 20 mm, through hole inner diameter 5 mm)
Cavity inner surface roughness: Ra50μm (pear finish)
Molding pressure: 15 MPa
Pressure in the cavity after decompression: 0.05 MPa
Composition of thermoplastic elastomer: Styrenic thermoplastic elastomer Hardness of thermoplastic elastomer: 35 ° (Shore A hardness)
Injection time: 5 seconds Cooling time: 60 seconds (comparative example)
The paper feeding roller 10 shown in FIG. 3 is used by using a paper feeding roller manufacturing apparatus having the same structure as that of the above embodiment except that the heating means for maintaining the thermoplastic elastomer in the flow path in a molten state is not provided. Produced.

2. Evaluation The fine shape of the inner surface of the cavity was satinly transferred to the surface of the paper feed roller obtained in the example. Also, the dimensional accuracy of the paper feed roller was good. Furthermore, the mold release from the cavity could be performed smoothly.
On the other hand, in the comparative example, the transferability of the fine shape by the satin finish was low, and the target fine shape could not be formed on the surface of the paper feed roller. Further, the cavity inner surface and the paper feeding roller after molding are in close contact with each other, and the paper feeding roller cannot be easily released even when pressed with an eject pin.

It is the schematic (longitudinal sectional view) which shows the mold closing state of 1st Embodiment of the manufacturing apparatus of the paper feed roller. It is the elements on larger scale of FIG. FIG. 2 is a perspective view of a paper feed roller manufactured by the paper feed roller manufacturing apparatus shown in FIG. 1. It is the schematic (longitudinal sectional view) which shows the mold closing state of 2nd Embodiment of the manufacturing apparatus of the paper feed roller. It is the schematic (longitudinal sectional view) which shows the mold closing state of 3rd Embodiment of the manufacturing apparatus of a paper feed roller. It is a figure (perspective view) which shows the core with which the manufacturing apparatus of the paper feed roller of 3rd Embodiment is mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus of paper feed roller 2 ... Mold 3 ... Eject pin 4 ... Nozzle 5 ... Flow path 7 ... Pressure reducing means 10 ... Paper feed roller 10 '... Paper feed roller group Solid 11 …… Shaft 12 …… Through hole 21 …… Moveable type 22 …… Fixed type 23 …… Cavity 24 …… Mounting part 25 …… Second cavity 26 …… Core 31 …… End face 32 …… Moving means 41 …… Second nozzle 51 …… Heating means 52 …… Second flow path 53 …… Second heating means 61, 62 …… Temperature adjusting means 71 …… Exhaust pump 72 …… Piping 73 …… Exhaust path 74 …… Small-diameter exhaust passage 211, 221 …… Cavity 212, 222 …… Contact surface 213 …… Core type

Claims (17)

A paper feed roller manufacturing apparatus for manufacturing a paper feed roller having a plurality of minute convex portions on a contact surface with paper by an injection molding method using a thermoplastic elastomer,
A mold having a cavity in which a plurality of concave portions corresponding to the plurality of minute convex portions are formed on an inner surface, and a flow path that communicates with the cavity and supplies the thermoplastic elastomer in a molten state;
Temperature control means for adjusting the temperature of the mold,
Heating means for maintaining the thermoplastic elastomer in the flow path in a molten state, and a paper feed roller manufacturing apparatus.   2. The apparatus for manufacturing a paper feed roller according to claim 1, wherein the temperature adjusting means adjusts the temperature of the mold during the injection of the thermoplastic elastomer to a temperature lower by 10 to 150 ° C. than the melting point of the thermoplastic elastomer. .   The paper feed roller according to claim 2, wherein the temperature adjusting means adjusts the temperature of the mold when the thermoplastic elastomer is cooled to a temperature lower by 20 to 100 ° C than the temperature of the mold during the injection. Manufacturing equipment.   4. The apparatus for manufacturing a paper feed roller according to claim 1, wherein the inner surface has a surface roughness Ra (specified in JIS B 0601) of 5 to 200 μm. 5.   5. The apparatus for manufacturing a paper feed roller according to claim 1, wherein the concave portion is formed by at least one method of blasting, transfer, and vibration cutting.   The paper according to any one of claims 1 to 5, wherein the forming die includes an eject pin for detaching the formed paper feeding roller from the forming die, and an end surface of the eject pin constitutes a part of the inner surface. Feed roller manufacturing equipment.   The paper feed roller manufacturing apparatus according to any one of claims 1 to 6, wherein the cavity has a cylindrical shape, and the flow path is opened at one end surface of the cylindrical shape of the cavity.   The paper feed roller manufacturing apparatus according to any one of claims 1 to 6, wherein the cavity has a cylindrical shape, and the flow path is open to a side surface of the cylindrical shape of the cavity.   9. The apparatus for manufacturing a paper feed roller according to claim 6, wherein the cavity has a cylindrical shape, and an end face of the eject pin constitutes one end face of the cavity having the cylindrical shape. .   10. The apparatus for manufacturing a paper feed roller according to claim 9, wherein the eject pin is configured to move in a direction of decreasing the volume of the cavity before the thermoplastic elastomer is solidified in the cavity. . The eject pin is composed of a porous body having at least part of continuous pores in which adjacent pores communicate with each other,
The apparatus for manufacturing a paper feed roller according to any one of claims 6 to 10, wherein the gas in the cavity is configured to be discharged to the outside of the cavity through the continuous holes. The mold is composed of a porous body having at least part of continuous pores in which adjacent pores communicate with each other,
12. The apparatus for manufacturing a paper feed roller according to claim 1, wherein the gas in the cavity is configured to be discharged to the outside of the cavity through the continuous holes.   The apparatus for producing a paper feed roller according to any one of claims 1 to 12, wherein a pressure when the thermoplastic elastomer is supplied into the cavity is 5 to 150 MPa.   The apparatus for manufacturing a paper feed roller according to any one of claims 1 to 13, wherein the thermoplastic elastomer has a Shore A hardness of 10 to 40 °.   15. The apparatus for manufacturing a paper feed roller according to claim 1, further comprising a decompression unit that decompresses the inside of the cavity.   The molding die is provided with a mounting portion for mounting the shaft of the paper feed roller, and in the state where the shaft is mounted on the mounting portion as an inner material for inner molding, the inner molding of the thermoplastic elastomer is performed. The apparatus for manufacturing a paper feed roller according to any one of claims 1 to 15, wherein the apparatus is configured to perform. The apparatus for manufacturing a paper feed roller according to any one of claims 1 to 15, wherein the paper feed roller manufacturing apparatus has a second mold for molding the shaft.

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