JP2008221473A - Mold of foam roller and foam roller molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold of a high-quality foam roller of little abnormal foaming such as a weld or a void constituted so as to reduce the cost of a liquid receiving cup and the cost of processing apparatus therefor by use of a piece having space volume. <P>SOLUTION: The mold of the foam roller is constituted so that the piece thereof has the casting function of the liquid receiving cup used in a conventional mold, that is, space volume for receiving the material used for forming the foamed elastic layer to store it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding die and a molding method for a foam roller mounted on an image forming apparatus such as a copying apparatus, an image recording apparatus, a printer, and a facsimile machine. More specifically, the present invention relates to a molding die and a molding method for a foam roller made of a core material and a cylindrical foam rubber material provided around the core material.

  In recent years, with the demands for miniaturization, high image quality and low price of electrophotographic apparatuses, functional rollers such as toner supply rollers, charging rollers, and transfer rollers incorporated in the electrophotographic apparatuses Lower prices are required. Accordingly, efforts have been made to reduce manufacturing costs while improving or maintaining the quality of these functional rollers.

  Under these circumstances, as a method for manufacturing the roller, in the conventional molding, a core material, a piece for holding the core material, and a pipe die are assembled, and then a foaming material is press-fitted from an injection port installed in the piece. Is generally known (Patent Document 1). There is also a method of casting a foam material from above the pipe mold (Patent Document 2).

  However, in the method of Patent Document 1, since a stress is applied to the foam material when the foam material is press-fitted, usable materials are limited. In the method of Patent Document 2, it is required to cast a foam material into a narrow space between the core material and the pipe mold wall surface, and molding is difficult depending on the size of the roller to be molded.

As a manufacturing method for solving those problems, a core material, a piece for holding the core material, and a pipe mold are assembled, then the material is injected into a liquid receiving cup for receiving the material, and then the molded A method has been proposed in which the mold is assembled and heat-cured (Patent Document 3). Referring to FIG. 1 (a), in this method, first, the core material 5 is arranged in the pipe mold 2, and the upper and lower ends of the core material 5 are held by the core material holding portions of the upper and lower frames, Preheat with temperature. On the other hand, after the foamed material is discharged into the liquid receiving cup 4 preheated to a predetermined temperature, it is assembled to the pipe mold 2. The foam material in the liquid receiving cup 4 is filled into the pipe mold 2 by natural foaming. Thereafter, the foamed material is cured by controlling the temperature at a predetermined temperature for a predetermined time, and the foamed roller is obtained by removing the mold.
JP-A-5-329855 Japanese Patent Laid-Open No. 5-318497 JP 2006-68943 A

  However, the method of Patent Document 3 has a problem that the filling material in the liquid receiving cup portion becomes a waste material as it is, and a processing device such as cleaning of the liquid receiving cup and application of a release agent is necessary, and the apparatus cost is high. There was a need for improvement. Also, the piece on the liquid receiving cup side of the foaming roller molding die is provided with ribs as flow paths in order to hold one end of the core material and secure the flow of the foaming roller material. This rib may cause quality degradation such as weld and void entrainment of the foaming roller to be molded, and improvement has been demanded.

  The present invention eliminates the liquid receiving cup, thereby reducing the liquid receiving cup cost, and further the processing cost of the liquid receiving cup, and a high-quality foam roller molding die and molding method free from voids and welds. The purpose is to provide.

  The present invention relates to a molding die for a foaming roller having a core material and a foamed elastic layer laminated around the core material, the pipe mold in which the core material is disposed, and the pipe mold And two pieces provided with a core material holding part for holding the core material on the central axis of the pipe mold, and either one of the two pieces has the foam elasticity A space volume for receiving and accumulating the material forming the layer, and the core material holding portion of the piece having the space volume is on the central axis of the bottom surface of the piece, from the bottom surface portion It has a protruding structure.

  Furthermore, the present invention is a method for molding a foam roller having a core material and a foamed elastic layer laminated around the core material, the core material, a pipe mold in which the core material is disposed, And a first step of preheating the upper piece holding the core material and a lower piece provided with a space volume, a second step of arranging the core material on the lower piece, and discharging a foam material into the lower piece And a third step of assembling the lower piece in which the foamed material is accumulated together with the upper piece to the pipe mold, and heat-curing the foamed material foamed inside the pipe mold, And a fifth step of releasing from the pipe mold.

  The present invention is also a foam roller manufactured by the molding method described above.

  By using the foaming roller molding die and method of the present invention, it is possible to eliminate the liquid receiving cup that has been conventionally used in molding, thereby reducing the liquid receiving cup cost and further the processing cost of the liquid receiving cup. It becomes possible to do. Further, in the molding, it is possible to reduce the filling material that has remained in the liquid receiving cup and had to be discarded. Furthermore, since the present invention has a mold structure in which ribs do not exist in the material flow path as in the case of a conventional cup on the side of the liquid receiving cup, it is possible to stably mold a high-quality foam roller without voids or welds. it can.

  First, the gist of the present invention will be described. In the present invention, the conventionally used liquid receiving cup 4 (FIG. 1A) is not used in foaming roller molding. Instead, a lower piece 6 (piece cup) having a holding portion for holding one end of the core material 5 and having a space volume for receiving and storing the material forming the foamed elastic layer (see FIG. 1 (b)) is used. By doing so, it is possible to obtain a high-quality foam roller in which abnormal foaming such as welds and voids is greatly reduced. Furthermore, since the conventional liquid receiving cup is not necessary, it is possible to reduce the molding die and peripheral device costs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The configuration of the foaming roller molding die and the roller molding method of the present invention will be described with reference to FIG. The roller molding die of the present invention is provided at both ends of the pipe die 2 on which the core material 5 is disposed, and holds the core material 5 on the central axis of the pipe die 2. It has two pieces (the upper piece 1 and the lower piece 6) provided with the core material holding | maintenance part 10 to perform.

  First, the pipe mold 2, the core material 5, the upper piece 1, and the lower piece 6 are preheated at a predetermined temperature. Next, the core material 5 is arranged in a lower piece (hereinafter referred to as a piece cup) 6 having a volume space for receiving and storing the foamed material. Then, after the foam material is discharged from above into the piece cup 6 preheated to a predetermined temperature, it is assembled to the pipe mold 2 together with the upper piece 1. The foam material in the piece cup 6 is filled into the pipe mold 2 by natural foaming. Thereafter, the foam material is heated and cured by controlling the temperature at a predetermined temperature for a predetermined time, and defoamed to obtain a foam roller.

  Next, the configuration of the piece cup 6 will be described with reference to FIG. FIG. 2B is a schematic view of the piece cup 6 of the present invention. The piece cup 6 includes a core material holding portion 10 that holds the core material 5. The core material holding part 10 is provided on the central axis of the bottom surface of the piece cup 6 so that the core material 5 can be held on the central axis of the pipe mold 2, and protrudes from the bottom surface part. Has a structure. Similarly to the piece cup 6, the upper piece 1, which is the other piece, also includes the core material holding portion 10 on the central axis thereof, but does not need to have a protruding structure like the piece cup 6. . Moreover, the piece cup 6 has a space volume 8 for receiving and accumulating the material forming the foamed elastic layer. In the conventional lower piece 3 (piece B), as shown in FIG. 2A, ribs 11 are arranged on the outer periphery of the core material holding portion 10 in order to fix the core material holding portion 10. Since this rib 11 is in the material flow path forming the foamed elastic layer, the occurrence rate of welds, voids, and the like of the foamed roller to be molded increases. On the other hand, in the present invention, the core material holding part 10 fixes the core material with a structure protruding from the central axis of the bottom surface of the piece cup 6, so that the rib 11 is not necessary. The piece cup 6 of the present invention does not obstruct the flow of foaming because there is no shielding like the rib 11 in the material flow path. Further, the space volume 8 can be increased or decreased by changing the height and diameter of the piece cup 6 depending on the shape of the foaming roller to be molded, so that the volume can be optimized according to the shape of the roller. In consideration of the ease of discharging the material from above into the space volume 8, it is preferable to increase the distance d between the core material holding part 10 and the piece cup inner diameter side part. However, even if the distance d is too wide, the molding die is enlarged, and the peripheral device that handles the molding die is enlarged and the cost is increased accordingly. Therefore, it is required to select an appropriate value.

  The material of the mold is not particularly limited as a mold member, and can be appropriately selected. For example, a metal member obtained by plating a steel material such as iron with nickel or chromium, or a metal member such as iron, copper, aluminum, stainless steel, or pre-hardened steel can be used. In addition to these, synthetic resins such as polycarbonate and polyamide, ceramics, and the like can also be used.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  In this embodiment, a mold having a configuration basically similar to that of the mold shown in FIG. 1B was used as the mold. Moreover, the space volume of the piece cup was made into the same quantity as the liquid receiving cup volume of a prior art. As the material of the mold, SUS304 was used for the pipe mold 2 and chemical nickel of HPM38 (pre-hardened steel) was applied to the piece A and the piece cup 6 by surface treatment.

  Next, the material, molding conditions, and manufacturing procedure of the molded rubber foam roller are shown. In implementation, a foaming roller having the shape shown in FIG. 3 was molded. The foaming roller has a core material and a foamed elastic layer laminated around the core material.

  First, as a mixed polyol, 100 parts by weight of FA-908, 0.5 parts by weight of diethanolamine, 1 part by weight of L5366, 0.1 part by weight of ToyoCat-ET, 0.5 part by weight of TEDA-L33, water ( 2 parts by weight of a foaming agent) was prepared and mixed. The FA-908 is a polyether polyol manufactured by Sanyo Chemical Co., Ltd. L5366 is a silicone-based foam stabilizer manufactured by Nippon Unicar Co., Ltd. The ToyoCat-ET is a tertiary amine catalyst manufactured by Tosoh Corporation. The TEDA-L33 is a tertiary amine catalyst manufactured by Tosoh Corporation. Then, TCO (Mitsui Takeda Chemical Co., Ltd. isocyanate, NCO% = 48) 29.5 parts by weight, M200 (Mitsui Takeda Chemical Co., Ltd. isocyanate, NCO% = 31) 7.4 parts and NCO index 100 A foamed material was prepared by mixing and stirring.

  A silicone oil release agent was applied to the molding die of this example and preheated to 65 ° C. Thereafter, the foamed material that has been mixed and stirred is discharged into a piece cup preheated to 65 ° C., a core metal of φ5 × 260 mm (L) is set in the piece cup and assembled with a pipe mold, and then the other end of the core material The side piece was assembled with the pipe mold. At that time, since the molding material discharged to the piece cup is a foam material, the inside of the pipe mold 2 is filled with the material by natural foaming. Thereafter, it was cured on a hot plate controlled at 65 ° C. for 10 minutes, and demolded to obtain a foaming roller of this example. The foam roller has a foam outer diameter of φ12 and a foam part length of 220 mm.

  In the foaming roller produced by the molding die of this example, abnormal foaming such as welds and voids was reduced by 80% compared to that produced by the conventional die (however, due to the cell connection of the foam) Excluding air accumulation). In addition, it was possible to reduce waste materials generated in the piece channel in the conventional molding die. Furthermore, since the liquid receiving cup is not used, the liquid receiving cup processing device is not required.

(A) Conventional foaming roller molding die, (b) Foaming roller molding die of the present invention. (A) Conventional foaming roller molding die, (b) Foaming roller molding piece of the present invention. Schematic of a foam roller.

Explanation of symbols

1 Upper piece (Koma A)
2 Pipe mold 3 Piece B
4 Liquid receiving cup 5 Core material 6 Lower piece (piece cup)
7 Foam 8 Material storage space volume 10 Core material holding part 11 Rib

Claims (3)

A molding die for a foam roller having a core material and a foam elastic layer laminated around the core material,
A pipe mold in which the core material is disposed;
Two pieces provided with both ends of the pipe mold and provided with a core material holding part for holding the core material on the central axis of the pipe mold;
Have
One of the two pieces has a space volume for receiving and accumulating the material forming the foamed elastic layer, and the core member holding portion of the piece having the space volume A foaming roller molding die having a structure on a central axis of a bottom surface and protruding from a bottom surface portion thereof. A foaming roller molding method comprising: a core material; and a foamed elastic layer laminated around the core material,
A first step of preheating the core material, a pipe mold in which the core material is disposed, and an upper piece for holding the core material and a lower piece provided with a space volume;
A second step of arranging the core material on the lower piece;
A third step of discharging the foam material into the lower piece;
A fourth step of assembling the lower piece, in which the foam material is accumulated, together with the upper piece to the pipe mold;
A fifth step of heat-curing the foamed material foamed inside the pipe mold and demolding from the pipe mold;
A foaming roller molding method comprising:   A foam roller produced by the foam roller molding method according to claim 2.