JPH0159911B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the manufacturing method of synthetic resin molded products such as key caps having a curved surface to which letters, symbols, etc. are applied. The object of the present invention is to provide a method for manufacturing synthetic resin molded products such as key caps with characters, symbols, etc., which have excellent abrasion resistance, in a simple process and without misalignment or misregistration.

Regarding key caps among synthetic resin molded products,
This will be explained below.

Key caps decorated with characters, symbols, etc. are often used in keyboards of push-button telephones, electronic desktop calculators, typewriters, word processors, personal computers, and the like.

By the way, there are various methods for producing key caps with letters and symbols, but the present inventor used a transfer sheet, which has been used for marking various articles, to produce letters and symbols on the surface of the key cap base material.
By inventing a transfer printing method using a transfer pad that dyes and forms patterns such as symbols, he succeeded in obtaining key caps with characters and symbols that are highly wear-resistant (Japanese Patent Application No. 38333/1983). ). In this method, a transfer sheet is formed by forming a pattern layer of characters, symbols, etc. on a base sheet using ink containing a heat-transferable dye, and a plurality of key caps are fixed by a fixing jig. The pattern layer is placed on the base material so as to be in contact with the transferred surface of the key cap base material, and then a transfer pad having a plurality of elastic protrusions with curved tips is used to transfer the transfer sheet to the base material. The transfer surface of the key cap base material and the pattern layer are brought into close contact with each other by pressing from the sheet side, and then heat treatment is performed while the transfer surface of the key cap base material and the pattern layer are in close contact with each other to form the pattern layer. The heat-transferable dye inside is thermally transferred to stain the transfer surface of the key cap base material with desired patterns such as characters, symbols, etc., and then the base sheet is removed to form characters, symbols, etc. on the surface of the key cap base material. This is a method of dyeing and forming patterns.

However, it has been found that a new problem arises when implementing the transfer printing method using this transfer pad. That is, since the top surface of the key cap base material usually has a concave curved surface in order to improve the feeling of contact with the fingertips, the key cap base material is This is because it is difficult to provide clear characters, symbols, etc. In other words, when the transfer sheet is placed on the key cap base material and then pressed using a transfer pad, the transfer sheet is brought into close contact along the concave curved surface of the top surface of the key cap base material, so it is locally This is because tension is applied, resulting in misalignment and misregistration, and in extreme cases, the transfer sheet may be torn and the pattern layer may be damaged.

The present inventors have completed the present invention as a result of various experiments and considerations in view of the above-mentioned problems. That is, in the present invention, a plurality of synthetic resin molded products each having a curved surface to be transferred are arranged in a plane, and a pattern layer of characters, symbols, etc. is formed on a base sheet using ink containing a heat transferable dye. A transfer sheet made of a material is placed so that the pattern layer is in contact with the surface to be transferred of the synthetic resin molded product, and then a transfer pad having a plurality of elastic protrusions with curved tips is used to perform the transfer. The transfer surface of the synthetic resin molded product and the pattern layer are brought into close contact with each other by pressing from the base sheet side of the sheet, and the heat-transferable dye in the pattern layer is heat-transferred by heat treatment in that state. A method for producing a synthetic resin molded product with characters and symbols, which comprises forming a desired pattern of characters, symbols, etc. on the transferred surface of the synthetic resin molded product, and then removing the base sheet,
A method for producing a synthetic resin molded product with characters and symbols, characterized in that at least before the transfer sheet is deformed by pressing the transfer pad against the transfer sheet, perforations are provided in advance between the pattern layers of the transfer sheet. .

Hereinafter, the present invention will be explained in detail based on the drawings.

The transfer sheet 1 used in the present invention has a basic layer structure in which a pattern layer 3 consisting of characters, symbols, etc. is laminated on a base sheet 2 of paper, plastic film, etc. ( (See Figure 1).

The pattern layer 3 consisting of characters, symbols, etc. is formed using ink containing a heat-transferable dye.

The key cap base material 4 according to the present invention may be made of any material as long as it can be dyed with the heat-transferable dye, such as polybutylene terephthalate, polycarbonate, and the like.

The transfer pad 5 used in the present invention is made of an elastic material such as silicone rubber, and has a plurality of protrusions each having a curved tip. Furthermore, this protrusion
Provide the number corresponding to the number of keycap base materials to be dyed.

Next, characters are printed on the key cap base material 4 using the transfer sheet 1 having the above structure and the transfer pad 5.
The method of adding symbols etc. will be explained.

First, a plurality of key cap base materials are arranged in a plane using a fixing jig. The key cap base material is usually
Arrange about 50 to 200 pieces.

Next, the transfer sheet 1 is placed on the key cap base material 4 so that the pattern layer 3 and the surface to be transferred of the key cap base material 4 are in contact with each other (see FIG. 2). At this stage, the pattern layer 3 is placed on the transfer surface of the key cap base material 4 and is not in close contact with it.

Next, using the transfer pad 5, transfer the transfer sheet 1
Before pressing from the base sheet 2 side, perforations 6 are provided between the pattern layers 3 of the transfer sheet 1 in advance. The step of providing this perforation, which is a feature of the present invention, can be implemented in various ways. For example, (1) a method of forming perforations 6 in the transfer sheet 1 by using a metal plate having a plurality of needles 7 or blades on its surface and lowering it from above the transfer sheet 1 placed on the key cap base material 4 ( 3), (2) a method of forming perforations 4 in the transfer sheet 1 almost simultaneously with pressing the transfer pad 5 by using a transfer pad 5 having a needle or blade between the elastic protrusions; (3) It is possible to consider a method in which perforations 6 are provided in the transfer sheet 1 as a separate process before the transfer sheet 1 is placed on the keycap base material 4.

The shape of the perforations 6 may be any shape that can disperse or relieve tension when local tension is applied to the transfer sheet 1, and may be shaped according to the shape of the key cap base material 4, taking into account workability, etc. It is good to design.
For example, one in which perforations 6 consisting of grid-like perforations are provided between the pattern layer 3 (see Figure 6), and one in which perforations 6 are provided in the top, bottom, left and right of the pattern layer 3 (see Fig. 6).
(see figure), etc. can be considered.

Next, using the transfer pad 5, transfer the transfer sheet 1
from the side of the base sheet 2 to bring the transfer surface of the key cap base material 4 and the pattern layer 3 into complete contact (see FIG. 4).

Thereafter, heat treatment is performed while the transfer surface of the key cap base material 4 and the pattern layer 3 are kept in close contact with each other. By doing so, the heat-transferable dye in the pattern layer 3 is thermally migrated, and a desired pattern of characters, symbols, etc. is formed on the surface of the key cap base material 4.

Thereafter, by removing the base sheet 2, a key cap with characters and symbols according to the present invention is obtained (see FIG. 5).

Since the method for manufacturing a keycap with characters and symbols according to the present invention has the above-described structure, it has the following effects. That is, when pressing the transfer sheet placed on the key cap base material with the transfer pad, even if tension is applied locally to the transfer sheet, the tension can be reduced by providing perforations in the transfer sheet in advance. Dispersion, misalignment due to relaxation,
It does not cause any misregistration.

Therefore, the method for manufacturing a keycap with characters and symbols according to the present invention has extremely excellent industrial utility value.

Although the above explanation has been about a method for manufacturing key caps with characters and symbols, the present invention is not limited to key caps as objects to be transferred, but can be applied to synthetic resin molded products whose surfaces to be transferred have a curved surface. It goes without saying that this is possible.

[Brief explanation of drawings]

FIG. 1 is an enlarged schematic cross-sectional view of a transfer sheet used in the present invention, FIGS. 2 to 4 are schematic cross-sectional views showing the steps of the present invention, and FIG. A schematic cross-sectional view of the key cap is shown. 6 and 7 respectively show embodiments of the shapes of perforations formed in the transfer sheet according to the present invention. In the figure, 1... transfer sheet, 2... base sheet,
3... pattern layer, 4... key cap base material, 5
... Transfer pad, 6... Perforation, 7... Needle, 8...
...Key cap with letters and symbols, 9...Dyeing section.

Claims (1)

[Claims] 1 A transfer sheet made by arranging a plurality of synthetic resin molded products with curved transfer surfaces in a plane, and forming a pattern layer of letters, symbols, etc. on a base sheet using ink containing a heat-transferable dye. is placed so that the pattern layer is in contact with the transferred surface of the synthetic resin molded product, and then a transfer pad having a plurality of elastic protrusions with curved tips is used to transfer the base sheet of the transfer sheet. The transfer surface of the synthetic resin molded product and the pattern layer are brought into close contact with each other by pressing from the side, and heat treatment is performed in that state to cause the heat transfer dye in the pattern layer to thermally migrate, thereby producing the synthetic resin molded product. A method for manufacturing a synthetic resin molded product with characters and symbols, which comprises forming a desired pattern of characters, symbols, etc. on the transferred surface of the transfer pad, and then removing the base sheet, at least onto the transfer sheet of the transfer pad. A method for manufacturing a synthetic resin molded product with characters and symbols, characterized in that before the transfer sheet is deformed by pressure, perforations are provided between the pattern layers of the transfer sheet.