JP2006264143A - Mold for manufacturing foam roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for manufacturing a foam roller which, in manufacturing the same by integral molding with a shaft, prevents the generation of cell roughening of foam cells and cracks in the ends of a molding and which can give the high-quality foam roller free from such defects. <P>SOLUTION: The mold 10 is used for manufacturing the foamed body roller comprising an shaft 1 and a foamed body supported on the outer periphery of the shaft. The mold comprises a hollow pillar-shaped mold main body 11 and cap members 12 which are inserted in the openings of both ends of the mold main body, hold the shaft end parts and at the same time plug the openings, wherein the manufacture of the foam roller is performed by injecting a raw material into the mold main body in such a state that the shaft is installed to penetrate the center line of the mold main body. The cap members 12 comprises, in the inner periphery of the parts holding the shaft 1 end parts, at least one air leak gap 12a which extends almost to the longitudinal direction and makes the inside and the outside of the mold main body 11 communicant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for manufacturing a foam roller (hereinafter also simply referred to as “mold”), and more specifically, can be suitably used for a foam roller used for various purposes in an image forming apparatus or the like, particularly a toner supply roller. The present invention relates to a mold for manufacturing a foam roller for manufacturing a foam roller.

  In electrophotographic image forming apparatuses such as copiers, printers, and facsimiles, a developing roller, a toner layer forming roller, and a cleaning roller are used in each process of development, toner layer formation, cleaning, paper feeding, and conveyance in an electrophotographic process. Various roller members such as a paper feed roller and a transport roller are used.

  These roller members have a structure in which an elastic material layer made of an elastic material or a resin material is supported around the shaft, and particularly in a member that requires a uniform contact surface such as a toner supply roller, In general, an elastic foam roller using an elastic foam such as polyurethane foam is used.

On the other hand, in manufacturing such an elastic body roller, as shown in FIG. 2, the hollow columnar mold body 21 and the ends of the shaft 1 are inserted and fitted into the openings at both ends, and the openings are opened. A method is known in which an elastic body is formed on the outer periphery of the shaft 1 by integral molding using a mold 20 having cap members 22a and 22b for closing the cap. For example, Patent Document 1 discloses a technique for obtaining a roller member by integral molding using a mold.
JP 2003-156930 A (Claims etc.)

  As shown in FIGS. 2 (a) and 2 (b), in the mold 20 as shown, a foam is formed by starting foaming of the raw material 30 from one end or the center of the mold, and is integrally formed with the shaft. Is used. In this case, conventionally, a groove 42a is provided between the mold main body 41 and the cap member 42 as shown in the partial enlarged view of the mold end portion of FIG. 3, and the air inside the mold is passed through the groove 42a. There was a leak.

  However, in the foam roller obtained by this method, cell roughness of the foam cell occurs at the foam end face corresponding to the part finally filled with the foam in the mold, that is, the molding end X, or the crack 31 is generated. There was a problem such as occurrence (see FIG. 2C).

  Accordingly, an object of the present invention is to produce a foam roller by integral molding with a shaft, thereby preventing the occurrence of cell roughening and cracking of the foam cell at the molding end, and not having such defects. An object of the present invention is to provide a mold for producing a foam roller capable of obtaining the above.

  As a result of intensive studies, the present inventors have found that cracks at the foam end are caused by the final residual air in the mold and the positions of holes for air leakage, and the cap member of the mold As a result of examining this structure from the viewpoint of the air leak position, it was found that leaking air from the periphery of the portion carrying the shaft of the cap member is effective in preventing cracks that are likely to occur in the vicinity.

That is, in order to solve the above-mentioned problems, the mold for manufacturing a foam roller of the present invention is a mold used for manufacturing a foam roller including a shaft and a foam supported on the outer periphery of the shaft. A hollow columnar mold body, and a cap member that is fitted into both end openings of the mold body to hold the shaft end and close the opening, and the center of the mold body In a foam roller manufacturing mold for manufacturing a foam roller by injecting a raw material into the mold body with the shaft penetrating on a wire,
The cap member has at least one, preferably at least four air leak grooves extending substantially in the longitudinal direction and communicating the inside and the outside of the mold main body on the inner periphery of the holding portion of the shaft end portion. It is what.

  The mold of the present invention is suitably used for manufacturing a toner supply roller.

  According to the present invention, when the foam roller is manufactured by integral molding with the shaft, the above-described configuration prevents the occurrence of cell roughening and cracking of the foam cell at the molding end, and does not have such a defect. It has become possible to realize a mold for manufacturing a foam roller capable of obtaining a high-quality foam roller.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 shows an enlarged sectional view of an end of a mold for producing a foam roller of the present invention. The illustrated mold 10 includes a hollow columnar mold main body 11 and a cap member 12 that is fitted into the openings at both ends to hold the end of the shaft 1 and close the opening, as shown in the figure. The foam roller is manufactured by injecting the foam raw material 30 into the mold body 11 with the shaft 1 penetrating the center line of the mold body 11.

  As shown in the drawing, in the mold 10 of the present invention, the cap member 11 extends substantially in the longitudinal direction on the inner periphery of the holding portion at the end of the shaft 1 so as to communicate the inside and the outside of the mold body 11 with each other. It is important to have By providing the air leak groove 12a in the portion in contact with the shaft of the cap member 12, it is possible to effectively reduce the occurrence of cracks that have conventionally been liable to occur around this, and as a result, a high-quality foam roller without defects. It became possible to manufacture.

  If at least one air leak groove 12a is provided, the desired effect of the present invention can be obtained. However, in order to reliably perform air leak, the air leak groove 12a should be point-symmetric with respect to the center of the shaft. It is preferable to provide at least two. More preferably, at least four are provided at equal intervals in the circumferential direction. As a result, air can be leaked in a more balanced manner, and the occurrence of molding defects such as pinholes and voids can be effectively prevented. More preferably, the number is about 8 to 12 at regular intervals in the circumferential direction.

  In the mold 10 of the present invention, there is no need to leak air between the mold body 41 and the cap member 42 as in the mold 20 shown in FIG. Absent. Therefore, air may remain at this end portion, but this end portion hits a portion that is cut off at the stage of obtaining the product roller (the dashed line in the figure indicates the cutting position), so a substantial problem occurs. Absent.

  In the mold 10 of the present invention, it is only important to provide the air leak groove 12a in the cap member 12, and the other parts of the cap member 12 and the shape and structure of the mold main body 11 are appropriately selected as in the prior art. Although it can be configured, it is preferably as follows.

  The shape and structure of the mold main body 11 are not particularly limited in the present invention, and can be selected according to a desired roller shape. As the material, ceramics can be used in addition to metals such as iron, copper, aluminum, and stainless steel, and stainless steel is preferably used from the viewpoint of strength, rust prevention, cost, and the like. Further, the material of the cap member 12 is not particularly limited as long as it can withstand the heating at the time of molding. However, from the viewpoint of releasability of the roller member after molding, it is preferable to use polypropylene. .

  The mold of the present invention is used for manufacturing a foam roller including a shaft and a foam supported on the outer periphery thereof. For example, for manufacturing a toner supply roller using polyurethane foam as a foam. It can be used suitably.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Example)
As shown in FIG. 1, a mold body 11 and a cap member 12 that holds the end of the shaft 1 are provided. A foam roller was produced using the columnar mold 10. On the inner periphery of the holding portion at the end of the shaft 1 of the cap member 12, four air leak grooves 12 a extending substantially in the longitudinal direction and communicating the inside and the outside of the mold body 11 are formed evenly in the circumferential direction.

First, a polyurethane material composed of a polyol component system and an isocyanate component system shown in Table 1 below was injected into the interior from the upper opening of the mold through an injection head using a high-pressure injector. The polyol component system and the isocyanate component system were impinged and mixed in the injection head at an injection pressure of 100 kg / cm ² and injected into the mold at a supply rate of 10 g / sec in a state of high-pressure foaming. Thereafter, the foamed polyurethane material injected into the mold was cured to obtain a foam roller in which a polyurethane foam layer was integrally formed on the outer periphery of the shaft 1.

  The obtained foam roller had a skin layer forming a continuous smooth surface on the surface thereof, and an opening portion communicating with the internal cell was formed in the skin layer. The foam roller was taken out from the mold body 1, and the foam was cut using a cutter at a position corresponding to the end surface in the longitudinal direction of the foam in the finished product roller (a chain line in FIG. 1).

  Cracks were not generated at the end of the foam roller of the obtained example, and no pinholes or voids were present. Moreover, the cell roughening of the foam cell was not seen, but the uniform foam was formed.

(Comparative example)
As shown in FIG. 3, a mold body 41 and a cap member 42 that holds the end of the shaft 1 are provided, and the inside of the mold is interposed through a groove 42 a provided between the mold body 41 and the cap member 42. A foam roller was produced in the same manner as in the example except that the mold 40 for leaking air was used.

  The obtained foam roller had a skin layer forming a continuous smooth surface on the surface thereof, and an opening portion communicating with the internal cell was formed in the skin layer. The foam roller was taken out from the mold main body 1, and the foam was cut using a cutter at a position corresponding to the end face in the longitudinal direction of the foam in the finished product roller (a chain line in FIG. 3).

  Cracks were observed near the outer periphery of the shaft at the end of the obtained foam roller of the comparative example. In addition, the presence of pinholes and voids was observed in the vicinity of the outer periphery of the shaft, and cell roughness of the foamed cells was also observed.

It is an edge part expanded partial sectional view which shows the metal mold | die for foam-roller manufacture concerning one suitable embodiment of this invention. (A), (b) is a schematic explanatory drawing which shows an example of the conventional metal mold | die for roller member manufacture, (c) is a schematic sectional drawing which shows the roller member obtained by this. It is an edge part expanded fragmentary sectional view which shows the conventional metal mold | die for foam roller manufacture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shafts 10 and 20 Molds 11 and 21 and 41 for foam roller manufacture Mold main bodies 12, 22a, 22b and 42 Cap member 12a Air leak groove 30 Foam raw material 42a Groove X Molding end

Claims (3)

A mold used in the manufacture of a foam roller comprising a shaft and a foam carried on the outer periphery of the shaft, the mold being inserted into a hollow column-shaped mold body and both ends of the mold body. A cap member that holds the shaft end and closes the opening, and injects the raw material into the mold body with the shaft penetrating on the center line of the mold body. In the foam roller manufacturing mold for manufacturing the foam roller,
The foam roller manufacturing method according to claim 1, wherein the cap member has at least one air leak groove extending in a substantially longitudinal direction to communicate the inside and the outside of the mold body on the inner periphery of the holding portion of the shaft end portion. Mold.   The mold for manufacturing a foam roller according to claim 1, wherein the mold has at least four air leak grooves.   3. A mold for producing a foam roller according to claim 1, which is used for producing a toner supply roller.

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