JP2007152894A - Roller mold and roller manufacturing method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller mold capable of manufacturing a roller reduced in the deflection of its outer diameter dimension. <P>SOLUTION: In the roller mold equipped with a mold main body 3 having opening parts 2A and 2B at both ends thereof and the cap parts 4A and 4B fitted to the opening parts 2A and 2B, the cap parts 4A and 4B have cap main bodies 5A and 5B having cylindrical opening parts provided to the central parts thereof, the support parts 6A and 6B arranged to the opening parts of the cap main bodies 5A and 5B to support the end parts of a roller shaft and plug members 7A and 7B freely movable in the direction of the roller shaft and having openings at both ends thereof. The cap main bodies 6A and 6B and the support parts 6A and 6B are connected to ribs 8A and 8B. The inside end part in the roller shaft direction of the injection side plug member 7A can be penetrated in the gap between the cylindrical opening part of the injection inside cap main body 5A and the injection side support part 6A while the discharge side plug member 7B can be penetrated in the discharge side cap main body 5B and the discharge side support part 6B has the protrusion 10 capable of being penetrated in the roller shaft direction inside opening 9 of the discharge side plug member 7B at the outside end part in the roller shaft direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a roller mold and a roller manufacturing method using the roller mold, and more particularly to a roller mold capable of manufacturing a roller having a small deflection of an outer diameter of an elastic layer.

  In general, an image forming apparatus such as a copying machine or a printer is provided with conductive rollers such as a developing roller, a charging roller, and a transfer roller around a photosensitive drum that holds a latent image. A shaft and an elastic layer formed on the outer periphery of the shaft are provided. Since the dimensional accuracy of these rollers greatly affects the quality of the image to be formed, the roller for the image forming apparatus is required to have high dimensional accuracy, in particular, small fluctuation of the outer diameter of the elastic layer. The

  On the other hand, conventionally, the conductive roller forms an elastic layer by using a roller mold having a cylindrical cavity, and then polishes the formed elastic layer to reduce the fluctuation of the outer diameter. Has been manufactured by a method. However, since this method requires both a molding process and a polishing process, the number of processes is large, and ancillary equipment such as a polishing apparatus is required. There was a problem in terms of productivity.

  On the other hand, in recent years, along with the downsizing of image forming apparatuses, in particular, downsizing of image forming apparatuses capable of forming color images, it has been required to downsize the rollers. On the other hand, in the method of polishing the elastic layer after forming the elastic layer using the mold described above, the outer diameter of the roller is sufficiently reduced while sufficiently reducing the fluctuation of the outer diameter of the elastic layer of the roller. Could not be made smaller.

JP 2001-129835 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a roller mold that solves the above-described problems of the prior art and that can produce a roller having a small outer diameter and a small deflection of the outer diameter of the elastic layer. . Another object of the present invention is to provide a method for producing a roller using such a roller mold.

  As a result of intensive studies to achieve the above object, the inventor has a cylindrical main body portion and cap portions positioned at both ends of the main body portion, and the cap portion has a cylindrical opening at the center. A cap body having a portion, a support portion disposed in the opening of the cap body and supporting the end of the shaft of the roller, and an inlet and a discharge port formed between the cap body and the support portion. The outer diameter of the elastic layer is small even if the outer diameter is small by manufacturing a roller using a roller molding die having a structure in which the support portion and the cap body are connected by a rib. The present inventors have found that a roller having a small runout can be obtained and completed the present invention.

That is, the roller mold of the present invention is a roller mold having a shaft and an elastic layer formed on the outer periphery of the shaft, and a cylindrical mold body having openings at both ends, and the mold body. An injection side cap portion of the elastic layer material fitted into one of the openings, and a discharge side cap portion of the elastic layer material fitted into the other opening of the mold body,
The injection-side cap portion includes a cap body having a cylindrical opening in the center, a support portion disposed in the cylindrical opening of the cap body and supporting an end of a roller shaft, and a roller shaft A plug member that is movable in the direction and has openings at both ends, and the inner end portion in the roller axial direction of the plug member can be press-fitted into the gap between the cylindrical opening of the cap body and the support portion. The cap body and the support portion are connected by a rib extending in the axial direction of the roller disposed on the outer periphery of the inner end portion in the roller axial direction of the support portion,
The discharge-side cap portion includes a cap body having a cylindrical opening in the center, a support portion disposed in the cylindrical opening of the cap body and supporting an end of a roller shaft, and a roller shaft A stopper member that is movable in the direction and has openings at both ends, and can be press-fitted into the cap body, and the support portion can be press-fitted into the inner opening in the roller axial direction of the stopper member at the outer end in the roller axial direction. The cap body and the support part are connected by a rib extending in the axial direction of the roller disposed on the outer periphery of the inner end part in the roller axial direction of the support part,
The inner end of the injection side plug member in the axial direction of the roller is press-fitted into the gap between the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side plug member is press-fitted into the discharge side cap body. At the same time, the convex part of the discharge side support part is press-fitted into the opening in the roller axial direction of the discharge side plug member, so that a cylindrical shape sealed between the outer surface of the roller shaft, the inner surface of the mold main body, and both cap parts is formed. It is characterized in that a cavity can be formed.

  According to the roller molding die, since the support portion that supports the end of the shaft of the roller and the cap body that is in contact with the inner surface of the mold body are fixed by the rib, the shaft of the roller to be molded and the elastic layer The concentricity can be made sufficiently high, and there is no need to further polish the molded roller. Therefore, according to the roller molding die, even when the outer diameter is small, it is possible to manufacture a conductive roller with a small fluctuation in the outer diameter of the elastic layer with a high yield.

  In addition, since the elastic layer material can be injected and discharged through the opening of both plug members, air is mixed when the plug member is moved and sealed in the axial direction of the roller after completely filling the elastic layer material. There is nothing to do. Further, since the cavity formed between the outer surface of the roller shaft, the inner surface of the mold body, and both cap portions is a closed space, the elastic layer material leaks out of the mold during the curing of the elastic layer material. Therefore, the so-called sink can be surely prevented.

  In a preferred example of the roller mold of the present invention, the stopper member of the discharge side cap portion further has a cylindrical portion that can be press-fitted into the inner peripheral surface of the cylindrical opening of the cap body of the discharge side cap portion. In this case, generation of voids can be further suppressed.

  In another preferred embodiment of the roller mold according to the present invention, the number of ribs connecting the cap body and the support portion is 3 or more, and the length of the ribs in the roller axis direction is 3 to 10 mm. is there. In this case, it is possible to uniformly inject the elastic layer material while ensuring a sufficient strength of the cap portion, so that it is possible to prevent the occurrence of welds.

In another preferred embodiment of the roller mold according to the present invention, the total area between the ribs on the cut surface by a plane perpendicular to the axis of the roller passing through the rib of the cap portion is 6 mm ² or more. In this case, since the pressure loss at the time of injection of the elastic layer material is sufficiently small, the roller can be continuously formed.

The roller manufacturing method of the present invention is a roller manufacturing method using the roller molding die,
The elastic layer material is injected from between the injection side ribs through the gaps between the injection side plug member and the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side Excess elastic layer material was discharged from the opening of the discharge side plug member through the gap between the rib and between the cylindrical opening of the discharge side cap body and the discharge side support portion, and filled with the elastic layer material. rear,
The inner end of the injection side plug member in the axial direction of the roller is press-fitted into the gap between the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side plug member is inserted into the discharge side cap body. The mold main body is hermetically sealed by press-fitting the convex portion of the discharge-side support portion into the inner opening in the roller axial direction of the discharge-side plug member. According to this method, air can be prevented from being mixed into the cylindrical space defined by the outer shaft surface of the roller, the inner surface of the mold main body, and both cap portions.

  According to the present invention, there is provided a roller molding die having a cylindrical main body portion and cap portions respectively positioned at both ends of the main body portion, wherein the cap portion has a cylindrical opening portion in the center; A support part disposed in the opening of the cap body and supporting the end of the shaft of the roller; and a plug member for closing the inlet and the outlet formed between the cap body and the support part; By using a roller molding die having a structure in which the support portion and the cap body are connected by a rib, a roller having a small deflection of the outer diameter of the elastic layer can be manufactured even if the outer diameter is small. it can.

  Hereinafter, a roller mold according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an example of a roller mold according to the present invention at the time of injecting an elastic layer material, and FIG. 2 is a cross-sectional view of an example of a roller mold according to the present invention at the time of sealing after injecting an elastic layer material. 3 is an enlarged view of the injection side cap portion of the roller mold shown in FIG. 1, FIG. 4 is an enlarged view of the injection side cap portion of the roller mold shown in FIG. 2, and FIG. 6 is an enlarged view of the discharge side cap portion of the roller mold shown in FIG. 1, FIG. 6 is an enlarged view of the discharge side cap portion of the roller mold shown in FIG. 2, and FIG. 7 is a line VII-VII in FIG. FIG. 8 is an enlarged sectional view of a preferred example of the discharge side cap portion of the roller mold according to the present invention at the time of injecting the elastic layer material, and FIG. 9 is an injection of the elastic layer material. Afterwards, suitable for the discharge side cap portion of the roller mold according to the present invention at the time of sealing It is an enlarged sectional view of the.

  The roller mold shown in FIGS. 1 and 2 is a roller mold having a shaft 1 and an elastic layer formed on the outer periphery of the shaft 1, and is a cylindrical shape having openings 2A and 2B at both ends, respectively. Mold body 3, elastic layer material injection side cap 4 </ b> A fitted in one opening 2 </ b> A of mold body 3, and elastic layer material fitted in the other opening 2 </ b> B of mold body 3 The discharge side cap portion 4B.

  In addition, it does not specifically limit as a material of the said mold main body 3, A synthetic resin, a metal, etc. can be used. Further, the material of the cap portions 4A and 4B is not particularly limited, and for example, synthetic resins such as polypropylene, polyethylene, and nylon can be used.

  In the illustrated roller forming mold, as shown in FIGS. 3 and 4, the injection side cap portion 4A includes an injection side cap body 5A having a cylindrical opening at the center, and a cylindrical shape of the injection side cap body 5A. 6A, an injection side support 6A that supports the injection side end of the roller shaft 1 and an injection side plug member 7A that is movable in the axial direction of the roller and has openings at both ends. Here, the inner end in the roller axial direction of the injection side plug member 7A can be press-fitted into the gap between the cylindrical opening of the injection side cap body 5A and the injection side support 6A. The injection-side cap body 5A and the injection-side support portion 6A are formed by injection-side ribs 8A extending in the axial direction of the roller disposed on the outer periphery of the roller-side inner end portion of the injection-side support portion 6A. It is connected.

  Further, as shown in FIGS. 5 and 6, the discharge-side cap portion 4B includes a discharge-side cap body 5B having a cylindrical opening at the center, and a cylindrical opening of the discharge-side cap main body 5B. A discharge-side support portion 6B that supports the discharge-side end portion of the shaft 1 of the roller, and a discharge-side plug that is movable in the axial direction of the roller and has openings at both ends and can be press-fitted into the discharge-side cap body 5B. Member 7B. Here, the discharge side support portion 6B has a convex portion 10 that can be press-fitted into the opening 9 on the inner side in the roller axial direction of the discharge side plug member 7B at the outer end in the roller axial direction. Further, the discharge-side cap body 5B and the discharge-side support portion 6B are formed by discharge-side ribs 8B extending in the axial direction of the rollers disposed on the outer periphery of the roller-side inner end portion of the discharge-side support portion 6B. It is connected.

  The injection side support 6A disposed in the cylindrical opening of the injection side cap body 5A is connected to and integrated with the injection side cap body 5A by the injection side rib 8A, as shown in detail in FIG. The cylindrical opening of the injection side cap body 5A and the injection side support 6A are arranged concentrically. Here, a plurality of ribs 8A are arranged on the outer periphery of the injection-side support portion 6A, and the gaps between the ribs 8A serve as the injection port 11 for the elastic layer material. On the other hand, although not shown, the cut surface of the discharge-side cap portion 4B by a plane perpendicular to the shaft 1 of the roller passing through the rib 8B is the same as that in FIG. 7, and excess elastic layer material is between the ribs 8B. Pass through.

  In the illustrated example of the roller mold, the injection side rib 8A passes through both the openings of the injection side plug member 7A and the gap between the cylindrical opening of the injection side cap body 5A and the injection side support 6A. The elastic layer material is injected from between the discharge side ribs 8B and the gap between the discharge side cap body 5B and the cylindrical opening of the discharge side cap body 5B and the discharge side support part 6B. Excess elastic layer material is discharged from the opening, and the gap between the shaft 1 and the mold body 3 is filled with the elastic layer material. Here, the excess elastic layer material only needs to pass through at least the opening 9 inside the discharge-side plug member 7B in the roller axial direction. Then, after the elastic layer material is completely filled in the gap between the shaft 1 and the mold body 3, the inner end of the injection side plug member 7A in the roller axial direction is connected to the cylindrical opening of the injection side cap body 5A. The discharge-side cap member 7B is press-fitted into the gap with the injection-side support portion 6A, and the discharge-side cap member 7B is press-fitted into the discharge-side cap member 7B. The cylindrical cavity 12 sealed between the outer surface of the roller shaft 1, the inner surface of the mold main body 3, and the cap portions 4A and 4B is formed by press-fitting the convex portion 10 of the portion 6B. Thereafter, the elastic layer material in the cavity 12 is cured by maintaining the temperature and time appropriately selected according to the elastic layer material to be used, whereby the shaft 1 and the elastic layer formed on the outer periphery of the shaft 1 are obtained. The roller provided can be integrally formed. The discharge side plug member 7B only needs to be able to be press-fitted into any part of the discharge side cap body 5B. For example, when the discharge side cap body 5B is composed of a plurality of parts having different diameters as in the illustrated example, the discharge side cap member 7B A structure in which the main body 5B is press-fitted into a portion other than the cylindrical opening may be used.

  In the roller mold of the present invention, the discharge side plug member 7B further has a cylindrical portion 13 that can be press-fitted into the inner peripheral surface of the cylindrical opening of the discharge side cap body 5B, as shown in FIGS. It is preferable. Since the cylindrical portion 13 is present in the discharge side plug member 7B, the space formed between the discharge side plug member 7B, the discharge side cap body 5B, and the discharge side support portion 6B can be further reduced. Can be further suppressed.

  In the roller molding die of the present invention, it is preferable that the concentricity φ between the outer periphery of the cylindrical openings of the cap bodies 5A and 5B and the inner periphery of the support portions 6A and 6B is 15 μm or less. In addition, it is preferable that the shape of support part 6A, 6B is a cylindrical shape by which one end was sealed. Here, the concentricity φ is defined as twice the distance between the center point of the outer periphery of the cylindrical openings of the cap bodies 5A and 5B and the center point of the inner periphery of the support portions 6A and 6B. Since the outer peripheries of the cylindrical openings of the cap bodies 5A and 5B are in contact with the inner peripheral surface of the mold body 3, the outer peripheries of the cylindrical openings of the cap bodies 5A and 5B and the inner peripheries of the support parts 6A and 6B By making the concentricity φ 15 μm or less, the concentricity between the manufactured shaft 1 and the elastic layer can be made sufficiently high, and the fluctuation of the outer diameter of the roller is 70 μm or less, preferably 30 μm or less. be able to. Note that the runout of the outer diameter of the roller is defined as the difference between the maximum value and the minimum value of the distance measured by measuring the distance between the roller and the reference rod by rotating the roller parallel to the reference rod. It can be measured using a general shake measuring machine.

  In the roller molding die of the present invention, the number of ribs 8A and 8B connecting the cap bodies 5A and 5B and the support portions 6A and 6B is 3 or more in each of the cap portions 4A and 4B, and It is preferable that the length of the ribs 8A and 8B in the roller axis direction is 3 to 10 mm. If the number of ribs per cap part is less than 3, the strength of the cap part will be insufficient. Also, if the length of the rib in the axial direction of the roller is less than 3 mm, the strength of the cap portion is insufficient. On the other hand, if it exceeds 10 mm, it becomes difficult to uniformly inject the elastic layer material and welds are likely to occur. Although not particularly limited, the rib width is preferably in the range of 0.3 to 1 mm, and the rib height (that is, the cylindrical openings of the cap bodies 5A and 5B from the outer periphery of the support portions 6A and 6B). The distance to the inner periphery of the part is preferably in the range of 3 to 5 mm.

In the roller molding die of the present invention, the total area between the ribs on the cut surface by the plane perpendicular to the axis 1 of the roller passing through the ribs 8A and 8B of the cap portions 4A and 4B (that is, in FIG. The total area of the injection port 11 defined by the support 6A, the rib 8A, and the cylindrical opening of the cap body 5A is preferably 6 mm ² or more. If the total area between the ribs is less than 6 mm ² , the pressure loss during filling of the elastic layer material is large, and continuous molding of the conductive roller becomes difficult.

  In forming a roller using the roller forming die of the present invention, as the shaft 1 of the roller, for example, a metal core made of a solid body such as iron, stainless steel, aluminum, or the like is hollowed out. A metal shaft such as a metal cylinder or a highly conductive plastic shaft can be used.

  On the other hand, for the elastic layer of the roller, it is preferable to use urethane foam obtained by mechanical stirring and foaming of a urethane raw material, that is, mechanical floss foamed urethane. The urethane foam is produced by a method in which bubbles are mixed by mechanically stirring a urethane raw material without using a foaming agent. Here, examples of the urethane material include a polyol and a polyisocyanate, or a urethane prepolymer synthesized from a polyol and a polyisocyanate, and a chain extender. The urethane material further includes a catalyst, a foam stabilizer, a conductive agent, and the like. can do.

  In the method for manufacturing a roller according to the present invention, the injection-side rib is formed via both openings of the injection-side plug member 7A and the gap between the cylindrical opening of the injection-side cap body 5A and the injection-side support 6A. The elastic layer material is injected from between 8A, and the discharge side plug member 7B is passed through the gap between the discharge side ribs 8B and the cylindrical opening of the discharge side cap body 5B and the discharge side support part 6B. After the excess elastic layer material is discharged from the opening of the nozzle and the gap between the shaft 1 and the mold body 3 is completely filled with the elastic layer material, the inner end of the injection side plug member 7A in the roller axial direction is the injection side. Press-fitting into the gap between the cylindrical opening of the cap body 5A and the injection-side support 6A, and press-fitting the discharge-side plug member 7B into the discharge-side cap body 5A, and the roller shaft of the discharge-side plug member 7B In the opening 9 inside By press-fitting the convex portion 10 of the serial discharge side support portion 6B, to seal the mold body 3. According to the method of the present invention, after the elastic layer material is completely filled, the injection side plug member 7A and the discharge side plug member 7B are pressed into the mold body 3 while discharging the excess elastic layer material. By sealing, air can be prevented from being mixed into the cylindrical space formed by the outer surface of the shaft 1 of the roller, the inner surface of the mold body 3, and the cap portions 4A and 4B.

It is sectional drawing of an example of the roller shaping | molding die according to this invention at the time of elastic layer material injection | pouring. It is sectional drawing of an example of the roller shaping | molding die according to this invention at the time of sealing after injection | pouring of elastic layer material. It is an enlarged view of the injection side cap part of the roller mold shown in FIG. It is an enlarged view of the injection side cap part of the roller mold shown in FIG. It is an enlarged view of the discharge side cap part of the roller mold shown in FIG. It is an enlarged view of the discharge side cap part of the roller mold shown in FIG. It is sectional drawing of the roller shaping | molding die in alignment with the VII-VII line of FIG. It is an expanded sectional view of the suitable example of the discharge side cap part of the roller mold according to this invention at the time of elastic layer material injection | pouring. It is an expanded sectional view of the suitable example of the discharge side cap part of the roller shaping | molding die according to this invention at the time of sealing after elastic layer material injection | pouring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 axis | shaft 2A injection | pouring side opening part of mold main body 2B discharge side opening part of mold main body 3 mold main body 4A injection side cap part 4B discharge side cap part 5A injection side cap main body 5B discharge side cap main body 6A injection side support part 6B discharge side support Portion 7A Injection-side plug member 7B Discharge-side plug member 8A Injection-side rib 8B Discharge-side rib 9 Opening on the inner side in the roller axial direction of the discharge-side plug member 10 Convex portion on the outer end in the roller axial direction of the discharge-side support member 11 Inlet 12 Cavity 13 The cylindrical part of the discharge side plug member that can be press-fitted into the inner peripheral surface of the cylindrical opening of the discharge side cap body

Claims (5)

A molding die for a roller comprising a shaft and an elastic layer formed on the outer periphery of the shaft,
The roller mold includes a cylindrical mold body having openings at both ends, an injection-side cap portion of an elastic layer material fitted into one opening of the mold body, and the other mold body. A discharge side cap portion of the elastic layer material fitted in the opening,
The injection-side cap portion includes a cap body having a cylindrical opening in the center, a support portion disposed in the cylindrical opening of the cap body and supporting an end of a roller shaft, and a roller shaft A plug member that is movable in the direction and has openings at both ends, and the inner end portion in the roller axial direction of the plug member can be press-fitted into the gap between the cylindrical opening of the cap body and the support portion. The cap body and the support portion are connected by a rib extending in the axial direction of the roller disposed on the outer periphery of the inner end portion in the roller axial direction of the support portion,
The discharge-side cap portion includes a cap body having a cylindrical opening in the center, a support portion disposed in the cylindrical opening of the cap body and supporting an end of a roller shaft, and a roller shaft A stopper member that is movable in the direction and has openings at both ends, and can be press-fitted into the cap body, and the support portion can be press-fitted into the inner opening in the roller axial direction of the stopper member at the outer end in the roller axial direction. The cap body and the support part are connected by a rib extending in the axial direction of the roller disposed on the outer periphery of the inner end part in the roller axial direction of the support part,
The inner end of the injection side plug member in the axial direction of the roller is press-fitted into the gap between the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side plug member is press-fitted into the discharge side cap body. At the same time, the convex part of the discharge side support part is press-fitted into the opening in the roller axial direction of the discharge side plug member, so that a cylindrical shape sealed between the outer surface of the roller shaft, the inner surface of the mold main body, and both cap parts is formed. A roller mold capable of forming a cavity.   2. The roller molding according to claim 1, wherein the plug member of the discharge-side cap portion further includes a cylindrical portion that can be press-fitted into an inner peripheral surface of a cylindrical opening of a cap body of the discharge-side cap portion. Type.   2. The roller molding according to claim 1, wherein the number of ribs connecting the cap body and the support portion is three or more, and the length of the ribs in the roller axial direction is 3 to 10 mm. Type. ^2. The roller mold according to claim 1, wherein a total area between the ribs in a cut surface by a plane perpendicular to an axis of the roller passing through the rib of the cap portion is 6 mm ² or more. A method for producing a roller using the roller mold according to claim 1,
The elastic layer material is injected from between the injection side ribs through the gaps between the injection side plug member and the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side Excess elastic layer material was discharged from the opening of the discharge side plug member through the gap between the rib and between the cylindrical opening of the discharge side cap body and the discharge side support portion, and filled with the elastic layer material. rear,
The inner end of the injection side plug member in the axial direction of the roller is press-fitted into the gap between the cylindrical opening of the injection side cap body and the injection side support part, and the discharge side plug member is inserted into the discharge side cap body. A method for producing a roller, wherein the mold main body is sealed by press-fitting and press-fitting a convex portion of the discharge-side support portion into an inner opening in the roller axial direction of the discharge-side plug member.

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