JPH032667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing key caps decorated with characters, symbols, etc., and the object thereof is to easily manufacture key caps decorated with characters, symbols, etc. with excellent wear resistance. The purpose is to provide an economical manufacturing method using a simple process.

Conventionally, key caps with letters, symbols, etc.
For example, keycaps used in keyboards of push-button telephones, desktop computers, typewriters, word processors, personal computers, etc. are manufactured by the following method. Namely, (1) a method of printing octopuses on the surface of the molded key cap, (2) a method of pouring colored ink into the recesses of the surface of the engraved key cap, and (3) a method of printing the main body of the key cap and the patterned parts such as letters and symbols with a different color material. It is manufactured using a method such as injection molding using so-called unique molding.

However, each of these key cap manufacturing methods has the following drawbacks, and at present no satisfactory method has yet been obtained. In other words, method (1) (i) has major problems with physical properties such as abrasion resistance because the printing ink is piled up on the surface of the keycap base material, and it cannot withstand long-term use. (ii) When trying to form characters, symbols, etc. in multiple colors on one key cap, it is extremely difficult to register each color, and (iii) There are disadvantages such as poor key touch feel. are doing. Method (2): (i) It is necessary to make a mold for each character and symbol, which increases the cost of the mold; (ii) Color ink is poured into each key cap, and then it is unnecessary. (iii) As with method (1), it is extremely difficult to form characters, symbols, etc. in multiple colors on one key cap, as it requires a process of wiping off the ink, which requires manpower and has extremely low productivity. (iv) dust tends to accumulate in the recesses of letters, symbols, etc., and the key cap surface tends to get dirty; and (v) the touch of the keys is also poor. Similar to methods (i) and (2), method (3) requires the production of a mold for each character and symbol.
The cost of molds is high; (ii) forming characters, symbols, etc. in multiple colors on one key cap requires extremely complicated processes such as three-color molding and four-color molding; (iii) characters. , it is difficult to express thin line parts such as symbols, etc. In particular, methods (2) and (3), which require a mold to be manufactured for each character or symbol, are completely unsuitable in the current situation where rockets are becoming smaller and more diverse. There is.

In view of the above-mentioned drawbacks, the present inventors completed the present invention as a result of various experiments and research. That is, the present invention provides a transfer sheet 3 in which a pattern layer 2 of characters, symbols, etc. is formed on a base sheet 1 using an ink containing a heat-transferable dye, which is made of a synthetic resin that thermally diffuses the heat-transferable dye. The pattern layer 2 is placed so as to be in contact with the surface of the key cap base material 4, and then the transfer pad 5 is pressed from the base sheet 1 side of the transfer sheet 3 to bring the surface of the key cap base material 4 and the pattern layer 2 together. The pattern layer 2 is brought into close contact with the surface of the key cap base material 4, and then heat-treated while the surface of the key cap base material 4 and the pattern layer 2 are in close contact with each other, thereby thermally diffusing the heat-transferable dye in the pattern layer 2 to form a desired color on the surface of the key cap base material 4. This method of manufacturing a keycap with characters and symbols is characterized in that a pattern of characters, symbols, etc. is formed thereon, and then the base sheet 1 is peeled off.

Hereinafter, the present invention will be explained in more detail using the drawings.

The transfer sheet 3 used in the present invention includes a base sheet 1 and a pattern layer 2 consisting of characters, symbols, etc.
(See Figure 1).

The base sheet 1 may be a plastic film such as polyethylene terephthalate, polybutylene terephthalate, vinyl chloride, or nylon, paper such as glassine paper, kraft paper, coated paper, or art paper, cellophane film, or composite paper thereof. be.

The pattern layer 2 consisting of characters, symbols, etc. is formed using ink containing a heat-transferable dye. The heat-transferable dye is one that can be thermally diffused during heat treatment and dye the surface of the key cap base material 4. Such heat-transferable dyes include disperse dyes, oil-soluble dyes,
Examples include basic dyes, and any suitable one may be used.

The key cap base material 4 according to the present invention may be made of any synthetic resin as long as it can be dyed with the heat-transferable dye. For example, key cap base materials molded using polyethylene terephthalate, polybutylene terephthalate, polycarbonate, triacetate, diacetate, polyether sulfone, aromatic nylon, 66-nylon, etc. can be used. Although their shape varies depending on the purpose, the top surface, that is, the part that comes into contact with the fingertips, usually has a slightly concave shape in order to improve the feel with the pads of the fingers. . The present invention is particularly suitable for those exhibiting such a shape.

It goes without saying that the present invention can be applied not only to those having a concave top surface as described above, but also to those having a flat top surface. Furthermore, it can also be applied to parts exhibiting a convex shape, such as the side surfaces of key caps.

As the transfer pad 5 used in the present invention, an elastic body such as silicone rubber is used, for example. Further, the shape of the transfer pad 5 is such that the tip thereof has a curved surface. More specifically, when the portion of the key cap base material 4 forming the pattern layer 2 has a concave shape, it is desirable to use an elastic body that has a convex shape with a radius of curvature slightly smaller than the radius of curvature of that portion. This is because when pressing the transfer sheet 3 with the transfer pad 5, the tip of the transfer pad 5 first comes into contact with the transfer sheet 3, and then gradually comes into contact from the center toward the periphery. The air between the sheet 3 and the key cap base material 4 is successfully removed, and the key cap base material 4
This is because the surface and pattern layer 2 are in complete contact with each other. Furthermore, when the part of the key cap base material 4 forming the pattern layer 2 has a convex shape, an elastic body having a concave shape having a radius of curvature slightly larger than that of that part is used for the same reason as described above. It's okay.

Further, the hardness of the transfer pad 5, for example, the hardness of silicone rubber, is preferably about 10 to 50 degrees. This is because if it is harder than this, it will be difficult to make the pattern layer 2 adhere to the surface of the key cap base material 4 when pressed, and if it is softer than this, the resistance of the silicone rubber will be weakened and continuous transfer printing processing will be difficult. This is because it is inappropriate for

Next, characters are printed on the key cap base material 4 using the transfer sheet 3 having the above structure and the transfer pad 5.
The method of adding symbols etc. will be explained.

First, the transfer sheet 3 is placed so that the pattern layer 2 and the surface of the keycap base material 4 face each other (see FIG. 2). At this time, registration is performed so that the pattern contacts a predetermined position on the surface of the keycap base material 4. At this stage, the pattern layer 2 is placed on the surface of the key cap base material 4 and is not in close contact with it.

Next, using the transfer pad 5, press the transfer sheet 3 from the base sheet side, and press the key cap base material 4.
The surface and the patterned layer 2 are completely brought into close contact (see FIG. 3).

Thereafter, heat treatment is performed while the surface of the key cap base material 4 and the pattern layer 2 are kept in close contact with each other. By doing so, the heat-transferable dye in the pattern layer 2 is thermally diffused, and a desired pattern of characters, symbols, etc. is formed on the surface of the key cap base material 4.
The heat treatment can be carried out by pressing with a heated transfer pad 5, by heating the key cap base material 4 in advance and then pressing with the transfer pad 5, or by pressing the key cap base material 4 with the surface of the key cap base material 4. There is a method of leaving the patterned layer 2 in a heated atmosphere while being in close contact with it. As the method for preheating the key cap base material, there are radiant heating methods such as a heater using an infrared light bulb, a gas infrared heater, a far infrared heater, and a convection heating method such as a hot air circulation heater. The heating conditions may be the temperature and time at which the heat-transferable dye is thermally diffused, and are usually 150 to 230°C and about 5 to 60 seconds.

Thereafter, by peeling off the base sheet 1, a keycap with characters and symbols according to the present invention is obtained (see FIG. 4).

The method for manufacturing a keycap with letters and symbols according to the present invention has the above-mentioned structure and has the following effects. That is, (1) since the key cap obtained by the present invention has characters, symbols, etc. dyed on it, it has extremely excellent physical properties such as abrasion resistance. Therefore, it can withstand long-term use. Also, unlike engraved key caps, dust does not accumulate in the recesses of characters, symbols, etc., and the feel of the key touch is not impaired. (2) Since the key cap base material does not require molding for each character or symbol, the cost of molding molds, which was one of the major problems when manufacturing key caps, is low, making it economical. It is. (3) Since the transfer sheet used in the present invention only prints desired characters, symbols, etc. on the base sheet, it is easy to express thin line parts such as characters, symbols, etc., and multiple characters can be printed on one key cap. It is also easy to form characters, symbols, etc. with different colors.
Furthermore, it can easily accommodate the recent trend toward smaller rockets and a greater variety of products. (4) Since the transfer pad is used to heat and dye the key cap base material surface and the pattern layer of the transfer sheet in complete contact, there is no misalignment of letters, symbols, etc., and beautiful letters and symbols are produced.
A key cap with symbols etc. is obtained. (5) The manufacturing process requires no labor and is highly productive, allowing for mass production. (6) Since it uses a transfer sheet, for example, when forming characters, symbols, etc. on the key cap of a keyboard such as an electronic desktop calculator, all characters, symbols, etc. should be formed on the transfer sheet. On the other hand, if a corresponding keycap base material is prepared, transfer printing processing can be performed at one time. Therefore, the method of manufacturing a keycap with characters and symbols according to the present invention is extremely useful in industrial applications.

Examples will be shown and explained below. All "parts" represent "important parts."

Example 1 Mirror images of 100 characters for key cap printing were printed on 70 g/m ² kraft paper by screen printing using ink having the composition below to obtain a transfer sheet.

(Parts by weight) Ethyl cellulose N-200 (manufactured by Hercules)
Part 15 Hostersam Blue HBL (manufactured by Hoechst)
10 parts Solbetsuso 150 50 parts Solbetsuso 100 10 parts n-butanol 15 parts Next, 100 key caps made of polybutylene terephthalate whose top surface has a concave portion with a radius of curvature of 17.5 mm were arranged on a jig and preheated at 210°C for 5 minutes. . Thereafter, the transfer sheet was placed on the preheated key cap in register.

After that, a hemispherical convex part with a radius of curvature of 10.0 mm was
190 silicone rubber transfer pads with 100 pieces
After preheating to .degree. C., heat and pressure were applied from above the transfer sheet for 20 seconds. Thereafter, when the base sheet was peeled off, normal blue letters were formed on the top surface of the concave key cap.

Next, a head abrasion test was performed on the surface of the key cap obtained in this way with 80 mesh carborundum at a head of 1.5 m, a flow rate of 450 g/min, and a contact surface of 45 degrees for 10 minutes. It was not removed.

[Brief explanation of the drawing]

FIG. 1 shows an enlarged schematic cross-sectional view of a transfer sheet used in the present invention, and FIGS. 2 to 4 each show enlarged schematic cross-sectional views of the manufacturing process according to the present invention. In the figure, 1... base sheet, 2... pattern layer,
3... Transfer sheet, 4... Key cap base material, 5
... Transfer pad, 6... Pattern (dyed part).

Claims (1)

[Scope of Claims] 1. A transfer sheet formed by forming a pattern layer of characters, symbols, etc. on a base sheet using an ink containing a heat transferable dye, which is made of a synthetic resin that thermally diffuses the heat transferable dye. placing the pattern layer in contact with the surface of the keycap base material, then pressing a transfer pad from the base sheet side of the transfer sheet to bring the surface of the keycap base material and the pattern layer into close contact;
Thereafter, heat treatment is performed while the surface of the key cap base material and the pattern layer are kept in close contact with each other, thereby thermally diffusing the heat-transferable dye in the pattern layer to form desired patterns such as characters and symbols on the surface of the key cap base material. A method for producing a key cap with characters and symbols, which comprises forming a key cap, and then peeling off the base sheet. 2. The method for manufacturing a key cap with characters and symbols as set forth in claim 1, wherein the transfer pad is an elastic body exhibiting a convex shape. 3. The method for manufacturing a key cap with characters and symbols as set forth in claim 1, wherein the transfer pad is an elastic body having a concave shape.