JPH05139564A - Thin-walled belt for carrying use - Google Patents

Abstract

PURPOSE:To facilitate production of a thin-walled belt with high dimensional accuracy by forming a thin-walled cylindrical formed body by injecting a rubber into a cavity formed by a metallic mold body and a core, and after removing the metallic mold, reversing the inner and the outer surface of this formed body, and making the obtained outer surface to be the carrying surface. CONSTITUTION:A cavity of a thin-walled cylindrical shape to form a thin-walled belt is formed by means of a metallic mold body 1 and a core 2. A recessed part to form this cavity 3 is provided to the metallic body 1, and a heater 4 to achieve heating or insulation is usually inserted into the metallic mold body 1. The cavity 3 is provided with at least one ring gate 5 at an intermediate part in the axial direction, and the distance where the injected rubber from a spool 6 flows is shortened, preventing generation of troubles such as scorch. After the thin-walled cylindrical formed body is formed and vulcanized by such a forming device, the metallic mold body 1 is opened, and removed, and the inner and the outer surfaces of the formed body are reversed. The desired thin-walled belt is completed by making the obtained outer surface to be the carrying surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyor thin-walled belt used in an automatic document feeder of a copying machine.

[0002]

2. Description of the Related Art In an OA device such as a copying machine or a facsimile equipped with an automatic document feeding mechanism capable of continuously copying a plurality of documents, a conveyed material such as paper or film is accurately and stably placed at a predetermined position. Since it is necessary to convey the belt, slipping and meandering of the conveyor belt must be prevented, and the conveyor belt is required to have a high dimensional accuracy and a uniform conveyor surface.

Conventionally, as this kind of conveying belt, a belt made of an elastomer such as rubber or thermoplastic resin has been known. For example, in JP-A-1-255527, a thermoplastic elastomer is extruded. It has been proposed that a seamless tube having high productivity be obtained by extruding from a machine to form a seamless tube and cutting the seamless tube into a ring shape.

However, the above-mentioned Japanese Patent Laid-Open No. 1-255252.
In No. 7, since an extruder is used, E which requires vulcanization
It was not possible to obtain a rubber-made conveyor belt such as PDM or NBR, and it was not possible to obtain a rubber-made conveyor belt that has sufficient frictional force between the original and the original to reliably convey the original.

Further, in order to obtain a rubber conveyor belt, a rubber sheet having a predetermined thickness is wound around the surface of a cylindrical mandrel, heat-molded, and then demolded to polish the surface to a predetermined thickness and both ends are Although it is also finished by cutting in parallel, it requires multiple molding steps, mainly due to the need for thinness and quality requirements, resulting in poor yield and production efficiency and enormous manufacturing cost. is doing.

[0006]

DISCLOSURE OF THE INVENTION In view of the above, the present invention provides a rubber thin-walled conveyor belt obtained by a simple, high-yield, and highly productive process. It is also intended to have a uniform conveying surface which is excellent in dimensional stability and does not cause slipping or meandering even when used by being attached to equipment.

[0007]

The present invention has as its basic means that a rubber conveyor belt is obtained by injection molding or transfer molding. Rubber is injected into a cavity formed by a mold body and a core. The thin-walled cylindrical molded body formed by opening the mold body and reversing the inner and outer surfaces of the thin-walled cylindrical molded body, and using the newly-formed outer surface as the transport surface. Is the gist.

[0008] Further, the gist of a thin-walled conveyor belt is such that an uneven surface is formed on the surface of the core, the inner and outer surfaces of the thin-walled cylindrical molded body are reversed, and the newly-conveyed outer surface is roughened. To do.

[0009]

With the above construction, a conveyor belt can be obtained easily and efficiently by injection molding or transfer molding, and it can retain the sufficient frictional force of rubber such as EPDM to ensure the original conveyance. It can be carried out.

Since the parting line of the mold is not formed on the transfer surface of the transfer belt, the transfer surface can be made uniform and has high dimensional accuracy, and slips and meandering can be prevented when using the document feeder of the copying machine. It does not occur and no stripes of parting lines are generated on the copy paper.

Further, due to the uneven pattern of the core surface, the carrying surface formed by this surface is uniformly roughened without forming a parting line, and a more reliable friction force with the original can be maintained. ..

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a thin-walled conveyor belt according to the present invention, FIG. 2 is a longitudinal sectional view of a mold showing an example of a mold used for molding this belt, and FIG. It is an A'sectional view.

One of the features of the thin-walled conveyor belt of the present invention is that it is obtained by employing an injection molding method or a transfer molding method, which has a relatively simple manufacturing apparatus and high productivity.

First, a mold set in an injection molding machine or a transfer molding machine (hereinafter, both are simply referred to as a molding machine) used in the present invention will be described. The mold body 1 and the core 2 form a thin-walled cylindrical cavity 3 for molding a thin-walled belt. The thickness of the cavity 3 is usually about 0.3 to 3 mm, and is determined by the intended thickness of the thin belt. Thickness is 0.3
If the thickness is less than mm, the injected rubber will not flow smoothly, and the product will have low tensile strength and excessive elongation during use, which is not preferable. However, the above range is preferable because there is no advantage of unnecessarily increasing the thickness. In the present embodiment, the concave portion for forming the cavity 3 is provided in the mold body 1 and, although it is preferable, it may be provided in the core 2.

A heater 4 for heating or keeping heat is usually inserted in the mold body 1. If necessary, also insert a heater in the core 2. Further, in order to make the belt conveying surface rough, a surface of the core 2 forming the cavity 3 is provided with an appropriate uneven pattern. If the surface of the core 2 is provided with a concavo-convex pattern, a parting line does not occur on the surface formed by this surface, and the core 2 can be evenly textured.

Next, the cavity 3 of the present invention is provided with at least one ring gate 5 at an intermediate portion in the axial direction. In this embodiment, one ring gate 5 is provided at the center. Since the ring gate 5 is located in the middle of the cavity 3, the flow distance of the injected rubber becomes short, troubles such as scorch can be easily avoided, and the rubber can be completely filled in every corner of the cavity 3. Further, since the injection distance of the rubber can be small because the flowing distance is short, the mold clamping pressure may be small, and burrs on the parting line are unlikely to occur. When the belt width does not exceed 500 mm, it is generally sufficient to provide one ring gate 5 at the center thereof. When a plurality of ring gates are provided, it is preferable that the ring gates are provided symmetrically in the axial direction. Further, the mold body 1 is mounted with a mold clamping machine (not shown) via the mold mounting plate 7. The mold does not matter whether it is a single mold or a multiple mold.

The mold thus prepared is set in a molding machine (not shown). The ring gate 5 is joined to the nozzle of the molding machine directly or via the spool 6. Rubber is injected from the molding machine into the cavity 3 of the mold set in the molding machine, molded and vulcanized, and then the mold body 1 is opened and demolded. The molded body that has been released from the mold has the inner and outer surfaces inverted and the core 2
The textured surface on the side is the outer transport surface 11, and the surface of the ring gate 5 on which the ridges 13 are formed is the inner surface 12.

The thin-walled cylindrical body manufactured in this manner has high dimensional accuracy and is seamless, and the surface of the mold body 1 on which the trace of the ring gate 5, the trace of rubber injection, and the parting line is formed is a conveyor belt. The inside of the conveyor belt 10 can be used as it is as it is without the need for secondary processing such as polishing to remove these.

[0019]

According to the present invention, it is possible to expect a product having a uniform thickness and a high dimensional accuracy, even though it is a rubber-made thin-walled conveyor belt which can be obtained with high productivity by an injection molding method or a transfer molding method.

Further, the inner and outer surfaces of the molded body are reversed, the core side capable of uniform graining is used as the conveying surface, and the ring gate trace, the elastomer injection trace, and the mold body surface with the parting line are inside. Since there is no need for secondary processing such as polishing, there is no parting line on the conveying surface, and dimensional accuracy and dimensional stability are excellent, so the belt does not slip or meander during use, and it can be used as copy paper. There is no risk of streaks or the like due to the parting line being transferred.

The convex stripes of the ring gate mark can be used as a guide for preventing meandering, but can also be used as a conveyor belt having smooth inner and outer surfaces by polishing it if necessary.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a thin transport belt of the present invention.

FIG. 2 is a vertical cross-sectional view of a mold showing an example of a mold used to mold the thin-walled conveyor belt of the present invention.

FIG. 3 is a sectional view taken along the line AA ′ of FIG.

[Explanation of symbols]

1: Mold body, 2: Core, 3: Cavity, 4:
Heater, 5: Ring gate, 6: Spool, 7: Mold mounting plate, 10: Conveyor belt, 11: Outer conveying surface, 1
2: Inner surface, 13: ridge.

Claims (2)

[Claims] 1. A thin cylindrical molded body formed by injecting rubber into a cavity formed by a mold body and a core,
A thin-walled belt for transportation, characterized in that the inner and outer surfaces of the thin-walled cylindrical molded body, which is released from the mold body by opening, are reversed so that the newly outer surface serves as a transportation surface. 2. The core surface is formed into an uneven surface,
The thin-walled conveyor belt according to claim 1, wherein the inner and outer surfaces of the thin-walled cylindrical molded body are reversed and the newly-conveyed outer surface is roughened.