JPH0768557A - Vulcanizing Mold of Thin Rubber Belt and Method for Manufacturing Thin Rubber Belt - Google Patents

Abstract

(57) [Abstract] [Purpose] When vulcanizing and molding a thin rubber belt used as a base paper conveyance for a copying machine, the purpose is to shorten the molding cycle time for each time and increase the production efficiency. [Structure] A core mold 16 having a thin-walled cylindrical shape, a core mold 16 having a circular cross section disposed inside outer molds 12, 14, a core mold 22 inserted and arranged in the hollow inside of the pipe mold 20, and a pipe. It is configured so as to include pipe receivers 24 and 26 that support the ends of the mold 20, and a planar heater 38 is arranged in a gap 32 formed between the pipe mold 20 and the core mold 22. The planar heater 3 attached to the inner peripheral surface of the core mold 20
The pipe mold 20 can be heated at 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vulcanization mold for a thin rubber belt and a method for manufacturing a thin rubber belt using the same.

[0002]

2. Description of the Related Art An endless annular thin rubber belt 100 (having a thickness of about 1 mm) as shown in FIG. 4 is used for carrying raw paper in a copying machine. The thin rubber belt 100 has been conventionally manufactured as follows.

FIG. 5 shows the structure of a vulcanizing mold used for manufacturing the thin rubber belt 100. In the figure, 102 and 104 are an upper mold and a lower mold as outer molds, and 106 is a heating plate for heating the molding mold through these outer molds.

Reference numeral 108 denotes a core mold having a circular cross section, which is arranged inside an outer mold composed of an upper mold 102 and a lower mold 104.
Is an annular molding space formed between the upper mold 102 and the lower mold 104 and the core mold 108.

The core mold 108 is composed of one member as a whole, and a hollow portion 114 is formed in the center thereof, and a rod heater 112 is inserted therein. Bar heater 11
2 is for keeping the core mold 108 warm.

Thin rubber belt 1 using this vulcanizing mold
In the conventional manufacturing method of No. 00, the unvulcanized rubber sheet is wound around the outer peripheral surface of the core mold 108 and set in the molding space 110, and then the unvulcanized rubber sheet is held for a predetermined time in the mold clamping state. Pressurizing and heating, and then vulcanization molding is performed.
The thin rubber belt 100 shown in (1) was obtained as a product.

[0007]

By the way, in manufacturing the thin rubber belt 100 by the present method, the unvulcanized rubber for the vulcanization mold is maintained while the vulcanization mold is kept at the same high temperature as during the vulcanization molding. When the sheets are set, the unvulcanized rubber sheet has a small thickness, so that vulcanization progresses during the work, which causes a problem of product failure.

Therefore, conventionally, as shown in FIG. 6, the mold is once cooled from a high temperature A during vulcanization molding to a temperature B lower than this by forced cooling, and then an unvulcanized rubber sheet is set. Then, the vulcanization molding of the thin rubber belt 100 was performed by raising the temperature of the vulcanization mold to the high temperature A necessary for vulcanization molding and maintaining it for a predetermined time.

However, in the case of the conventional manufacturing method using the above-mentioned vulcanizing mold, since the mold is heated by using only the heating plate arranged outside the outer mold as a heat source, the unvulcanized rubber sheet is set. It takes a long time to heat the vulcanization mold from the low temperature B for high temperature to the high temperature A for vulcanization, which increases the cycle time for vulcanization of the thin rubber belt 100. This was a hindrance to productivity improvement.

The bar heater 112 arranged in the center of the core mold 108 is, as described above, only the core mold 108.
It is for keeping heat and does not substantially function as a heat source for raising the temperature of the cooled core mold 108 to the high temperature A for vulcanization molding.

[0011]

The present invention has been made to solve the above problems, and its gist is as follows.
(A) an outer mold, (b) a core mold arranged inside the outer mold, and (c) a molding space for the thin rubber belt formed between the outer mold and the core mold. And the core type is (a)
A pipe die forming the outer peripheral portion thereof, (b) a core die inserted inside the pipe die in a state of forming a constant gap in the radial direction with respect to the inner peripheral surface of the pipe die, (c) Interposed between the pipe-shaped and core-shaped ends,
A pipe holder that supports the end of the pipe mold; and (d) a planar heater that is housed in the gap between the pipe mold and the core mold and that is attached along the inner peripheral surface of the pipe mold. A thin-walled rubber belt is manufactured by using a vulcanization molding die comprising.

[0012]

As described above, according to the present invention, the core type, which is conventionally formed as an integral body, is configured to include the pipe type, the core type, and the pipe receiver, and the inner peripheral surface of the pipe type is used. A sheet heater is attached to the sheet, and a thin rubber belt is manufactured by using a vulcanization molding die including such a core die. According to the present invention, once a non-vulcanized rubber sheet is set. The forcedly cooled vulcanization mold, particularly the pipe mold, which is a main part of molding in the core mold, can be quickly heated to the high temperature required for vulcanization and raised in temperature. As a result, the cycle time for vulcanization molding of the thin rubber belt can be greatly shortened, and the production efficiency can be increased.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, 10 is a hot platen, 12, 14
Are upper and lower molds as outer molds, and 16 is these upper molds 1
2, a core mold having a circular cross section disposed inside an outer mold composed of a lower mold 14. A thin annular molding space 18 is formed between the core mold 16 and the outer mold. The core mold 16 is a thin-walled cylindrical pipe mold 20, a thick-walled cylindrical core mold 22 inside thereof, and a pipe receptacle 2 at the end in the axial direction.
4 and 26 are included.

The one pipe receiver 24 is separate from the pipe mold 20 and the core mold 22. The pipe receiver 24 has a short cylindrical shape and is fitted to the outer peripheral surface of the end of the core mold 22 and is fixed to the end surface of the core mold 22.
It is locked by 8

The pipe receiver 24 has a large diameter portion on one end side, and a stepped surface 30 is formed on the outer peripheral portion of the large diameter portion. At this stepped surface 30, the end of the pipe mold 20 is formed. The parts are fitted and supported in a state where a predetermined gap 32 is formed between the parts and the core mold 22.

On the other hand, the other pipe receiver 26 is formed integrally with the core mold 22. A large diameter portion is also formed in the pipe receiver 26, and a stepped surface 30 is formed on the outer peripheral portion thereof, and the other end of the pipe die 20 is fitted and supported on the stepped surface 30.

A plug 34 is provided at one axially open end of the core mold 22. An axial through hole 36 is formed in the center of the plug 34. A lead wire 40 of a planar heater 38, which will be described later, is inserted through the through hole 36. The core die 22 also has a through hole 42 through which the lead wire 40 is inserted.

A sheet heater 38 is disposed in the gap 32 between the pipe die 20 and the core die 22, and the sheet heater 38 is attached along the entire inner peripheral surface of the pipe die 20. Has been done.

FIG. 3A shows the planar heater 38 in a developed state. In the figure, reference numeral 44 denotes a flexible long base sheet 44, and a plurality of (three in this example) sheet-shaped heaters 46 are attached to the base sheet 44.

FIG. 3B shows the sectional structure of the sheet heater 46. In this figure, 48 is an insulating layer,
The heating wire 50 is embedded so as to be sandwiched between these insulating layers 48. The heating wire 50 is distributed over the entire surface of the sheet-shaped heater 46. Reference numeral 52 is a terminal for connecting the lead wire 40 to the heating wire 50, and 56 is a fixing cap. As shown in FIG. 3A, the heating wire 50 of each sheet-shaped heater 46 is the lead wire 40.
Are connected to each other.

As described above, in this embodiment, the core portion of the core die 16 for forming the thin rubber belt is constructed as the thin pipe die 20, and the sheet heater 38 is attached along the inner peripheral surface thereof. Then, the pipe die 20 is directly heated by the planar heater 38.

Therefore, in this example, the upper die 12 and the lower die 1
When the outer mold and the core mold 16 composed of 4 and especially the pipe mold 20 are forcibly cooled and then cooled to a high temperature for vulcanization molding again, the heating plate 10 and the planar heater 38 are used.
The temperature can be raised rapidly by heating with the, and therefore the cycle time for vulcanization molding of the thin rubber belt can be shortened.

In addition, according to this example, by controlling the distribution pattern and distribution density of the heating wires 50 in the planar heater 38, it is possible to equalize the temperature distribution of the pipe mold 20 and the outer mold. Based on this, the product quality of the thin rubber belt as a vulcanized molded product can be improved.

Since the thin rubber belt has a small wall thickness, if the temperature distribution of the molding die is not uniform, this affects the product quality, but in this example, the temperature distribution of the molding die can be made uniform. Can improve product quality.

The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention is configured and modified in various forms and modes based on the knowledge of those skilled in the art without departing from the spirit of the invention. It is feasible.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vulcanization molding die for a thin rubber belt, which is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the same vulcanizing mold.

3A is an exploded view of the planar heater shown in FIGS. 1 and 2, and FIG. 3B is a sectional view taken along line BB in FIG.

FIG. 4 is a diagram showing an example of a thin rubber belt to which the present invention is applied.

FIG. 5 is a view of a vulcanization molding die of a thin rubber belt which has been conventionally used.

FIG. 6 is a diagram showing an example of a temperature rising / falling pattern of a vulcanization mold in one cycle of thin rubber belt vulcanization molding.

[Explanation of symbols]

 10 Hot Plate 12 Upper Mold 14 Lower Mold 16 Core Mold 18 Molding Space 20 Pipe Mold 22 Core Mold 24, 26 Pipe Receiving 32 Gap 38 Planar Heater 50 Heating Line

Claims (2)

[Claims] 1. A thin rubber belt formed by: (a) an outer mold; (b) a core mold disposed inside the outer mold; and (c) a thin rubber belt formed between the outer mold and the core mold. A molding die having a molding space, and the core die (a) is a pipe die forming an outer peripheral portion thereof;
(B) a core mold inserted inside the pipe mold in a state where a constant gap is formed in the radial direction with respect to the inner peripheral surface of the pipe mold; and (c) the pipe mold and the end of the core mold. A pipe receiver interposed between them to support the end of the pipe mold, and (d) housed in the gap between the pipe mold and the core mold and along the inner peripheral surface of the pipe mold. A vulcanization molding die for a thin rubber belt, characterized in that it is provided with a surface heater attached. 2. A thin rubber belt, comprising: (a) an outer mold; (b) a core mold disposed inside the outer mold; and (c) a thin rubber belt formed between the outer mold and the core mold. A molding die having a molding space, and the core die (a) is a pipe die forming an outer peripheral portion thereof;
(B) a core mold inserted inside the pipe mold in a state where a constant gap is formed in the radial direction with respect to the inner peripheral surface of the pipe mold; and (c) the pipe mold and the end of the core mold. A pipe receiver interposed between them to support the end of the pipe mold, and (d) housed in the gap between the pipe mold and the core mold and along the inner peripheral surface of the pipe mold. Using a vulcanization mold equipped with a pasted heater, the outer mold and pipe mold are forcibly cooled to a temperature lower than the temperature during vulcanization molding, and then unvulcanized in the molding space. After the rubber sheet is loaded, the outer mold and the pipe mold are heated again to the temperature at the time of vulcanization molding and held for a predetermined time, whereby the thin rubber belt is vulcanized and molded.