JP2007015117A - Mold for molding roller, roller manufacturing method and roller manufactured by them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding a roller which suppresses occurrence of burr or a flaw on the surfaces of both of a core material and the piece which supports the core material and excellent in durability or the like, and to provide a roller manufacturing method and the roller manufactured by them. <P>SOLUTION: In the mold for molding the roller having the core material 5, a pipe mold 2 for forming a cylindrical elastic layer on the outer periphery of the core material and at least two pieces 1 and 3 provided in both end parts of the pipe mold and equipped with core material holding parts for holding the core material in the pipe mold, at least the contact parts with the core material of the core material-holding parts 11 in two pieces are enhanced in hardness so that surface hardness is set to 50-70 at Rockwell C hardness (HRC). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mold for molding a roller, a method for manufacturing the roller, and a roller manufactured by these. In particular, a mold for forming a roller and a roller mounted on a developing device used for developing and visualizing an electrostatic latent image formed on an image carrier made of an electrophotographic photosensitive member or an electrostatic recording derivative And a roller manufactured by these methods.

In recent years, due to demands for miniaturization, high image quality, and low price of electrophotographic apparatus, high precision and low performance for functional rollers such as toner supply rollers, charging rollers, and transfer rollers incorporated in the electrophotographic apparatus. Pricing has been required.
On the other hand, efforts have been made to reduce the manufacturing cost while maintaining the quality of the functional roller in response to these requirements.
Further, in mass production of rollers, it is indispensable to automate a manufacturing apparatus to some extent. Therefore, a manufacturing apparatus that can be easily automated while maintaining the quality of the roller has been demanded.

Under these circumstances, a roller having a cylindrical elastic portion on the outer periphery of a core material, which is one of such functional rollers, conventionally has a core material disposed inside a pipe-shaped molding die. In general, a method of manufacturing by supporting by a piece provided at both ends of a mold and injecting a raw material into the mold to foam and solidify the mold has been used.
By the way, in the case of such a manufacturing method, in particular, it is required to reduce the eccentric amount of the elastic roller formed on the outer periphery of the core material as much as possible to improve the outer diameter deflection accuracy. Such demands are increasing more and more with the progress of image quality improvement.

For this reason, Patent Document 1 proposes that the cored bar holding portions of the pieces provided at both ends of the mold are formed of a material having a higher linear expansion coefficient than the material of the piece to improve the outer diameter deflection accuracy. This is because the cored bar is centered by expansion of the cored bar holding part due to heating during molding, and the position accuracy of the cored bar is improved, and as a result, the outer diameter deflection accuracy is improved.
In Patent Document 2, a proposal has been made to improve the outer diameter deflection accuracy by providing a large-diameter core insertion hole at the back of the core body holding portion. According to this, by providing the large-diameter core body insertion hole, the bending force does not act on the core body at the time of molding, and the outer diameter deflection accuracy is improved.
Japanese Patent Laid-Open No. 2002-292637 JP 2001-205639 A

By the way, in the above-mentioned conventional example, when the core material is arranged at the center of the pipe mold and the core material is held by the core material holding portions of the pieces provided at both ends of the mold, these core material and core A burr | flash and a crack will generate | occur | produce on the surface of the part which contacts a material holding | maintenance part.
Such burrs and scratches cause deterioration of the roller outer diameter fluctuation of the molded product, and also adversely affect the assembly of the roller to the developing device. In particular, when the core arrangement is automated by a manufacturing apparatus during molding, burrs and scratches are likely to occur due to a slight shift in the core arrangement position and difficulty in adjusting the force.
However, the conventional example described above is not always satisfactory in preventing the occurrence of such burrs and scratches. Further, the durability of these contact portions has been demanded for further improvement.

  In view of the above problems, the present invention suppresses the occurrence of burrs and scratches on the surface of the core material and the piece that supports the core material, and has excellent durability and the like. An object of the present invention is to provide a roller manufactured by these.

In order to achieve the above object, the present invention provides a molding die for a roller configured as follows, a method for manufacturing the roller, and a roller manufactured by these.
That is, the mold for molding the roller of the present invention includes a core material, a pipe mold for forming a cylindrical elastic layer on the outer periphery of the core material, and the pipe mold provided at both ends of the pipe mold. In a roller molding die having at least two pieces having a core material holding portion for holding the core material therein, at least a portion of the core material holding portion in the two pieces that is in contact with the core material, It is characterized by high hardness. At that time, it is more preferable that the surface hardness due to the increase in the hardness is Rockwell C hardness (HRC) 50 to 70, or Rockwell C hardness (HRC) 63 to 68.
Also, the roller manufacturing method of the present invention includes a core material, a pipe mold for forming a cylindrical elastic layer on the outer periphery of the core material, and provided in both ends of the pipe mold and disposed in the pipe mold. A roller manufacturing method for manufacturing a roller made of a cylindrical elastic layer on an outer periphery of the core material, the roller manufacturing method comprising: In production, the roller molding die described above is used to produce a roller made of a cylindrical elastic layer on the outer periphery of the core material.
The roller of the present invention is a roller having a core material and a cylindrical elastic layer formed on the outer periphery of the core material, and the above-described roller molding die or the method for manufacturing the roller described above It is characterized by being manufactured by.

  According to the present invention, on the surface of the core material and the piece that supports the core, the generation of burrs and scratches is suppressed, and the roller molding die excellent in durability and the like, the method for manufacturing the roller, and the manufacturing method using these Can be realized.

Hereinafter, as an example of a molding die according to an embodiment of the present invention, a molding die for an elastic roller made of a foam (hereinafter referred to as a foamed elastic roller) will be described with reference to the drawings.
FIG. 1 shows the configuration of a molding die for a foamed elastic roller, which is an example of an embodiment of the present invention.
FIG. 3 shows the configuration of the foamed elastic roller molded by the molding die according to the embodiment of the present invention.
In FIG. 1, 1 is an upper piece, 2 is a pipe mold, 3 is a lower piece, 4 is a liquid receiving cup, and 5 is a core.
Further, 6 is a foam having a core material 5 taken out from the cylindrical pipe mold 2 after molding as shown in FIG. 3, and 7 is a foam material filling port formed in the lower piece 3.
Reference numeral 11 denotes a core material holding portion for holding the core material 5 formed on the upper piece 1 and the lower piece 3.

Initially, the outline at the time of shape | molding a foaming elastic body roller using the metal mold | die of such a structure is demonstrated.
First, the core material 5 is arranged in the pipe mold 2, the upper and lower portions of the core material 5 are held by the core material holding portions 11 of the upper piece 1 and the lower piece 3, and the core material 5 is set at a predetermined temperature. Preheat. On the other hand, after the foam material is discharged into the liquid receiving cup 4 that has been preheated to a predetermined temperature, it is assembled to the molding die 2. The foam material in the liquid receiving cup 4 is filled into the pipe mold 2 through the foam material filling port 7 by natural foaming. Thereafter, the foamed material is cured by controlling the temperature to a predetermined temperature for a predetermined time, and demolding to obtain a foamed elastic roller.

The above is the outline of the foamed elastic roller molding process in the present embodiment. At this time, in the present embodiment, the hardness of the portion where the core material 5 and the core material holding portion 11 are in contact is HRC50 to 70, preferably HRC63 to 68, and the generation of burrs and scratches is suppressed. It has characteristics.
In conventional steel for general molds, the hardness is less than HRC50 and the surface hardness is not sufficient. For this reason, when the core material is held by the core material holding portions 11 of the upper piece 1 and the lower piece 3, burrs and scratches are easily attached to the portion where the core material 5 and the core material holding portion 11 are in contact. Once such burrs and scratches are generated, further burrs and scratches are produced in the subsequent molding, which has a problem of vicious circle. Moreover, even when the surface hardness is a high hardness of HRC 70 or more, it is not preferable from the viewpoint of a decrease in toughness.

On the other hand, as in the present embodiment, the hardness of the portion where the core material 5 and the core material holding portion 11 are in contact is set to HRC 50 to 70, preferably HRC 63 to 68, so that the core material and the piece are When a force is applied by contact, burrs and scratches are less likely to occur, and stable good product molding can be maintained over a long period of time. At that time, it is more desirable that the surface roughness of the hardened portion is small.
In the present embodiment, the means for increasing the hardness is not particularly limited. For example, carbon tool steel (SK), high speed tool steel (SKH), alloy tool steel (SKS, SKD), chromium molybdenum steel (SCM) , Etc. can be heat-treated. Alternatively, in addition to these, means such as hard chrome plating, hard alumite, tuftride, DLC treatment, etc. can be used.

  Further, as for the portion to be increased in hardness, it is sufficient that at least the portion in contact with the core material is subjected to high hardness treatment, but is not particularly limited. An example is shown in FIG. In FIG. 2, reference numeral 11 a denotes a core material support member that has been subjected to high hardness processing at a portion that contacts the core material 5 of the core material holding portion 11. As described above, not only the core member supporting member that is partially hardened is provided on the upper piece 1 and the lower piece 3, but also the whole piece may be hardened. However, when the whole piece is hardened, the deformation of the support member and the finish workability by the above-described hardening means are deteriorated, so that only the contact portion of the core material holding portion 11 with the core material is hardened. Is more preferable.

  As described above, when the hardness is partially increased, the mold material other than the high hardness portion is not particularly limited as a mold member. For example, use metal materials such as iron, copper, aluminum, stainless steel, pre-hardened steel, etc., as well as engineering plastics such as PEEK, ceramics, etc. Can do.

Although the manufacturing method of the foam rubber roller in the Example to which this invention is applied is demonstrated below, this invention is not limited at all by these Examples.
In this embodiment, a molding die having a structure basically similar to that of the molding die shown in FIG. 1 was used.
In the present embodiment, in the core holding part 11 of the upper piece 1 and the lower piece 3, the member 11a having a hardness of around HRC64 by heat-treating the alloy tool steel SKS31 shown in FIG. 2 is made of a piece of material HPM38 (prehardened steel). Press-fitted into the member 10a. As the material of the other mold, a pipe mold with SUS304 and a liquid receiving cup with HPM38 (prehardened steel) chemical nickel subjected to surface treatment was used.

Next, the material and molding conditions of the molded roller, and the manufacturing procedure will be shown.
In implementation, a roller having the shape shown in FIG. 3 was formed.
First, as a mixed polyol, FA-908 (Sanyo Chemical Co., Ltd. polyether polyol) 100 parts by weight, diethanolamine 0.5 part by weight, L5366 (Nihon Unicar Co., Ltd. silicone-based foam stabilizer) 1 part by weight, ToyoCat-ET (Tosoh Corporation tertiary amine catalyst) 0.1 parts by weight, TEDA-L33 (Tosoh Corporation tertiary amine catalyst) 0.5 parts by weight, water (foaming agent) 2 parts by weight were mixed. 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, so that NCO index 100 A foamed material was prepared by mixing and stirring. A silicon oil release agent was applied to the roller molding die (hereinafter referred to as “die”) of this example, and then a core metal of φ5 × 260 mm (L) was set in the die and preheated to 65 ° C. On the other hand, the foamed material that had been mixed and stirred was preheated to 65 ° C., discharged into a liquid receiving cup, and assembled with a mold. Since it is a foam material, the mold is filled with the material by natural foaming. Thereafter, it was cured in a hot plate controlled at 65 ° C. for 10 minutes and demolded to obtain a roller of this example. The roller has a foam outer diameter of φ12 and a foam part length of 220 mm.
Burrs and scratches generated in the conventional molding die can no longer be seen by using the molding die of this example. As described above, according to the mold of the present embodiment, it is possible to stably mold a foam roller having no burrs or scratches on the core material.

The figure which shows the structure of the metal mold | die for a foaming elastic body roller which is an example of embodiment of this invention. The structure of the piece in which the core material holding member by which high hardness processing was provided in the contact part with the core material in the core material holding part in embodiment of this invention is shown. The figure which shows the structure of the foaming elastic body roller shape | molded with the said metal mold | die in embodiment of this invention.

Explanation of symbols

1: Upper piece 2: Pipe die 3: Lower piece 4: Liquid receiving cup 5: Core material 6: Foam 7: Foam filling port 10a: Piece member 11 of material HPM38 (pre-hardened steel) 11: Core material holding portion 11a : Hardened core material support member

Claims (5)

A core material, a pipe mold that forms a cylindrical elastic layer on the outer periphery of the core material, and a core material holding portion that is provided at both ends of the pipe mold and holds the core material in the pipe mold. In a roller molding die having at least two pieces provided,
A roller molding die characterized in that at least a portion of the core material holding portion of the two pieces that comes into contact with the core material is hardened.   2. The roller molding die according to claim 1, wherein a hardened core material support member is provided in a portion of the core material holding portion that contacts the core material. 3.   3. The roller molding die according to claim 1, wherein the surface hardness due to the increase in hardness is Rockwell C hardness (HRC) of 50 to 70. 4. A core material, a pipe mold that forms a cylindrical elastic layer on the outer periphery of the core material, and a core material holding that is provided at both ends of the pipe mold and holds the core material arranged in the pipe mold A roller manufacturing method for manufacturing a roller made of a cylindrical elastic layer on the outer periphery of the core material,
A roller comprising a cylindrical elastic layer on the outer periphery of the core material using the roller molding die according to any one of claims 1 to 3 in manufacturing the roller. Manufacturing method.   A roller having a core material and a cylindrical elastic layer formed on the outer periphery of the core material, wherein the roller is a roller molding die according to any one of claims 1 to 3, or A roller manufactured by the method for manufacturing a roller according to claim 4.

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