JPH0737034B2 - Method for producing rubber-plastic coated sponge roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a rubber-plastic coated sponge roller used in a heat fixing portion of an electrophotographic copying machine, for example.

(Prior Art) Conventionally, as a rubber / plastic coated sponge roller used in a heat fixing portion of an electrophotographic copying machine, a sponge rubber is cylindrically coated on the surface of a core shaft, and silicone rubber having a constant thickness is formed on the outermost layer. A structure having a rubber / plastic layer is known.

Such a rubber / plastic coated sponge roller is manufactured as follows.

First, as shown in FIG. 3, a bottom member 2 in which a funnel-shaped taper surface is formed at the center of the upper surface of a cylindrical mold 1 held upright is formed.
Then, a predetermined amount of liquid rubber / plastic material 3 which has been degassed in advance is injected into the cylindrical mold 1. After this, the sponge roller 4 in which the sponge rubber 4b is cylindrically coated on the outer circumference of the rear shaft 4a is inserted by inserting a conical cap 5 into one end of the sponge roller 4, and the cap 5 is fitted into the tapered surface of the upper surface of the bottom member 2. Let Next, the lid member 6 having the support hole 6a for supporting the core shaft 4a in the center is fitted on the upper portion of the cylindrical mold 1, and the sponge roller 4 is concentrically positioned and fixed in the cylindrical mold 1. With the insertion of the sponge roller 4, the liquid rubber / plastic material 3 is ascended and filled into the gap between the inner wall of the cylindrical mold 1 and the sponge roller 4. In this state, the liquid rubber / plastic material 3 is cured to form a rubber / plastic layer, and then the rubber / plastic layer is extracted from the cylindrical mold 1 to manufacture a rubber / plastic-coated sponge roller.

(Problems to be Solved by the Invention) However, in such a conventional method for manufacturing a rubber / plastic-coated sponge roller, when the sponge roller 4 is inserted, unevenness of bubble marks is formed especially on the surface of the sponge rubber 4b. Therefore, there is a problem in that air is likely to be entrained in the liquid rubber / plastic material 3, and this air remains as bubbles in the rubber / plastic layer, which significantly deteriorates the quality of the product.

Also, in order to reduce the formation of such bubbles,
After molding the sponge rubber 4b, it is performed to dip and cure liquid rubber / plastic material on the surface to fill the irregularities on the surface and smooth it, but there is a problem that the number of steps is large and the work is complicated. .

Further, in this method, it is necessary to carry out secondary processing such as grinding after the liquid rubber / plastic material 3 is hardened, which further disadvantageously increases the number of steps and causes a considerable amount of material loss.

Therefore, the present invention has been made in order to eliminate such a conventional problem, it is possible to omit the dipping process after the sponge roller molding and the grinding process after curing, thereby significantly reducing the number of steps, Moreover, it is an object of the present invention to provide a method for producing a rubber / plastic-coated sponge roller, which is capable of producing a high-quality roller in which bubbles in the rubber / plastic layer are prevented from being produced with good yield.

[Structure of the Invention] (Means for Solving the Problems) In the method for manufacturing a rubber / plastic coated sponge roller of the present invention, a funnel-shaped tapered surface for guiding a core shaft is provided inside a cylindrical lower part that is held upright. The lower plug body with the material press-fitting hole formed in the center is fitted, and a sponge roller having a cylindrical sponge layer on the outer periphery of the core shaft is inserted into this cylindrical mold. To form a funnel-shaped tapered surface for guiding the core shaft inside and to fit an upper plug body with a degassing hole at the center, and then press-fit the liquid rubber / plastic material from the material press-fitting hole to cure it. Is characterized by.

Examples of the liquid rubber / plastic material used in the present invention include room temperature curing type silicone rubber, thiochol rubber, chloroprene rubber, elastic epoxy resin and the like.

(Operation) According to the method of the present invention, since the liquid rubber / plastic material is injected from the lower portion in the state where the sponge roller is incorporated in the cylindrical mold, air in the gap between the inner wall of the cylindrical mold and the sponge roller and the sponge roller are The air in the bubbles on the surface of the sponge layer is pushed up and discharged through the degassing holes, and the air is prevented from being entrained in the liquid rubber / plastic material.

Therefore, secondary processing such as dipping treatment on the surface of the sponge roller or grinding after hardening is substantially unnecessary, the manufacturing process is simplified, and material loss is prevented.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show rubber in one embodiment of the present invention.
It is a longitudinal section showing a manufacturing process of a plastic covering sponge roller.

As shown in these drawings, the molding apparatus used in this embodiment is a cylindrical mold 11 having the same inner diameter as the finished outer diameter of the roller held upright, and the inner portion of the cylindrical mold 11 fitted to the lower part. A lower plug 12 having a core-shaped guide-shaped funnel-shaped tapered surface 12a and a material press-fitting hole 12b formed in the center, and a funnel-shaped tapered surface for guiding the core-axis fitted inside the cylindrical mold 11 13
It is composed of an upper plug 13 forming a and having a degassing hole 13b opened in the center.

The tapered surface 13a of the upper plug 13 is provided with a groove 13c for deaeration.

Further, a nozzle 14 of a material press-fitting mechanism (not shown) is connected to the material press-fitting hole 12b of the lower plug body 12, and a pressing mechanism (not shown) that presses the upper plug body 13 in the axial direction is attached to the upper plug body 13. Omitted) is connected.

The present invention is carried out as follows using the molding apparatus configured as described above.

First, the cylindrical mold 11 is held upright, and the lower plug body 12 is fitted to the lower part thereof. Then, the sponge roller 15 having a structure in which the outer circumference of the core shaft 15a is concentrically covered with a cylindrical sponge rubber 15b is inserted into the cylindrical mold 11. Further, the upper plug 13 is fitted on the upper part of the cylindrical mold 11, the sponge roller 15 is concentrically positioned by the upper plug 13 and the lower plug 12, and the upper plug is pressed by the upper plug pressing mechanism at an appropriate pressure. The body 13 is pressed and fixed.

After that, the material press-fitting mechanism is operated, and the liquid rubber / plastic material 1 is supplied from the nozzle 14 through the material press-fitting hole 12b of the lower plug body 12.
6, for example, room temperature curable silicone rubber composition cylindrical
Press into 1 The liquid rubber / plastic material 16 pushes the sponge roller 15 upward due to the fluid pressure thereof and flows into the space between the sponge roller 15 and the cylindrical mold 11. On the other hand, the air in this space is extruded to the outside from the air vent groove 13c of the tapered surface 13a of the upper plug 13 through the deaeration hole 13b.

In this way, when the liquid rubber / plastic material 16 is filled and the space internal pressure and the material press-fitting pressure are balanced, the sponge roller 15 descends due to its own weight, and the end surface of the sponge roller 15 has a lower plug as shown in FIG. It is pressed against the tapered surface 12a of the body 12 to be in a close contact state.

After this, the nozzle 14 of the material press-fitting mechanism is removed, but the liquid rubber / plastic material 16 filled in the cylindrical mold 11 is cured while maintaining an appropriate internal pressure. After curing, top plug
The rubber / plastic coated sponge roller of the present invention is manufactured by removing 13 and pulling out the sponge roller from the cylindrical mold 11.

The rubber / plastic layer of the sponge roller thus obtained has no pinholes or air bubbles that can be identified with the naked eye. The desired rubber / plastic coated sponge roller can be obtained without performing.

In the present invention, the secondary processing is not particularly required as described above, but the accuracy can be further improved and the quality can be improved by adding a simple grinding process.

As described above, according to the method for manufacturing a rubber / plastic-coated sponge roller of the present invention, since the liquid rubber / plastic material is cast and hardened without entraining air, the front surface of the sponge roller is prevented. It is possible to manufacture a high-quality roller with good yield without performing secondary processing such as grinding after processing or curing. Therefore, economic efficiency is also improved.

[Brief description of drawings]

FIG. 1 and FIG. 2 show rubber in one embodiment of the present invention.
FIG. 3 is a vertical sectional view showing a manufacturing process of the plastic-coated sponge roller, and FIG. 3 is a vertical sectional view showing a conventional manufacturing process. 11 …… Cylinder type 12 …… Lower stopper 12a …… Tapered surface 12b …… Material press-fitting hole 13 …… Upper stopper 13a …… Tapered surface 13b …… Deaeration hole 15a …… Core shaft 15b …… Sponge rubber 15… … Sponge roller 16 …… Liquid rubber / plastic material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location B29K 105: 20 B29L 31:32 (72) Inventor Toshinori Asai 2-chome Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1-1 No. 1 Showa Cable Denki Co., Ltd. (72) Inventor Yoshiyuki Nuno 2-1-1, Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa

Claims (1)

[Claims] 1. A lower plug having a funnel-shaped tapered surface for guiding a core shaft inside and a material press-fitting hole opened at the center is fitted to the lower part of the cylindrical mold held upright, and the cylindrical mold is Then, a sponge roller provided with a cylindrical sponge layer on the outer periphery of the core shaft was inserted, and further, a funnel-shaped tapered surface for guiding the core shaft was formed inside the upper part of the cylindrical shape, and a deaeration hole was opened in the center. A method for producing a rubber / plastic-coated sponge roller, characterized in that an upper plug is fitted, and then a liquid rubber / plastic material is press-fitted and cured from the material press-fitting hole.