JPH0368820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin molded product with characters and symbols, and its object is to produce a synthetic resin molded product on which cut-out characters with excellent wear resistance are formed. That is, the object of the present invention is to provide a method for economically producing a dark-colored synthetic resin molded product with a pattern of light-colored characters, symbols, etc., which has excellent abrasion resistance, through a simple process.

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 have been various methods for manufacturing keycaps with patterns such as letters and symbols, but the applicant has previously developed a method for producing keycap base materials using transfer sheets that have been used to decorate various articles. He invented and filed an application for a transfer printing method using a transfer pad, which dyes and forms patterns such as letters and symbols on the surface (see Japanese Patent Laid-Open No. 155957/1983).
In this method, a transfer sheet is formed by forming a colored layer of characters, symbols, etc. on a base sheet using an ink containing a heat-transferable dye, and a transfer sheet is placed on a key cap base material.
Place the colored layers so that they are in contact with each other, then press the transfer sheet from the base sheet side using a transfer pad to bring the colored layer into close contact with the transferred surface of the key cap base material, By heating the surface and the colored layer while keeping them in close contact with each other, the heat-transferable dye in the colored layer is thermally transferred, and a desired pattern of characters, symbols, etc. is dyed on the transferred surface of the key cap base material. In this method, patterns such as letters and symbols are dyed and formed on the surface of the key cap base material by removing the transfer sheet. According to this method, key caps with patterns of characters, symbols, etc., which are excellent in wear resistance, can be manufactured economically through easy steps.

However, in this method, patterns such as letters and symbols are formed on the surface of the key cap base material by dyeing with a heat-transferable dye. The only fatal drawback was that it was not possible to form a light-colored pattern. Therefore, in order to apply patterns such as light-colored letters and symbols on the surface of a dark-colored keycap base material,
At present, the method described above cannot be applied, and the conventional method described below has to be relied upon.
Namely, (1) a method of printing octopuses on the surface of the molded key cap base material, (2) a method of pouring colored ink into the recesses on the surface of the key cap base material that has been engraved and molded, and (3) a method of patterning the key cap body and characters, symbols, etc. (4) So-called anti-color molding, in which patterns such as letters and symbols are formed on the surface of the key cap base material using ink with an anti-dye function, and then dyed. They had no choice but to rely on legal and other methods.

However, each of these key cap manufacturing methods has the following drawbacks. In other words, in method (1), printing ink is piled up on the surface of the keycap base material, so there are major problems with physical properties such as abrasion resistance, and it cannot withstand long-term use. It has some drawbacks, such as a poor feel when touching the keys.

Method (2) requires making a mold for each character/symbol, which increases the cost of the mold, and is completely unsuitable in the current situation where small lots and a wide variety of products are being produced. It requires a process of pouring colored ink into each key cap and then wiping off unnecessary ink, which requires manpower and is extremely low in productivity.Dust tends to accumulate in the recesses of letters and symbols, and the key cap surface gets dirty easily. It has drawbacks such as the ink easily coming off, it cannot withstand long-term use, and the touch of the keys is not good.

Method (3) has the advantage of having excellent physical properties such as abrasion resistance and a good feel when touching the keys, but as with method (2), each character/symbol is It is difficult to express fine line parts such as letters and symbols, and it is completely unsuitable in the current situation where small lots and a wide variety of products are being produced.
It has the following drawbacks.

Method (4) requires steps such as resist pattern printing, dyeing, and resist removal, and has the disadvantage of extremely low productivity.

In view of the current situation, the present inventors conducted intensive research and consideration in order to eliminate all of the above-mentioned drawbacks of the conventional technology, and as a result, the present inventors developed a transfer printing method using the above-mentioned transfer pad and the above-mentioned different color molding method. Alternatively, the inventors have discovered that all of the above-mentioned drawbacks can be overcome at once by combining this method with a resist dyeing method, and have finally completed the present invention. That is, the present invention provides a transfer sheet having, on a base sheet, a colored layer in which desired characters, symbols, etc. are formed as punched characters using an ink containing a heat-transferable dye; First, using a synthetic resin molded product in which the part forming the cut-out characters is light-colored compared to the color of the heat-transferable dye, and the other part is dark-colored, which is the same color as the heat-transferable dye, Place the transfer sheet so that the cut-out character part and the light-colored part of the synthetic resin molded product are in contact with each other, and then use a transfer pad to press the transfer sheet from the base sheet side to separate the transferred surface and the colored layer. The transfer sheet is then heat-treated while in close contact, and the heat-transferable dye in the colored layer is thermally transferred onto the transfer surface to form the desired cut-out characters on the transfer surface, and then the transfer sheet is removed. This is a method for producing a synthetic resin molded product with characters and symbols.

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

The transfer sheet 1 used in the present invention is composed of a base sheet 2 and a colored layer 3 consisting of cut-out characters such as letters and symbols (Figures 1-a and 1-b).
(see figure).

The base sheet 2 may be paper such as medium-quality paper, high-quality paper, or uncoated paper such as kraft paper, metal foil such as aluminum, a sheet-like material obtained by laminating the above-mentioned paper and metal foil, or plastic film. etc. can be mentioned.

The colored layer 3 in the present invention consists of cut-out characters 4 such as letters and symbols, and is formed using an ink containing a heat-transferable dye. At this time, what is important in the present invention is that the heat-transferable dye dyes the portion other than the cut-out characters formed on the transferred surface 6 of the key cap base material 5 in the same color as the background color of the key cap body. Selective use of dyes such as In other words, a dye is used that can dye the light-colored portion A of the transfer surface 6 of the keycap other than the cut-out characters so that it becomes the same color as the dark-colored portion B.

The heat-transferable dye is appropriately selected from among dyes that can be thermally diffused during heat dyeing and dye the surface of the key cap base material 5, such as disperse dyes, oil-soluble dyes, and basic dyes. As a forming means, an appropriate means such as a screen printing method is used.

The transfer sheet 1 used in the present invention is as described above, but in order to improve the adhesion to the key cap base material 5 or to ensure the positioning with respect to the key cap base material 5,
It is preferable to form a half cut or a perforation between the four parts of the cut-out characters (Utility Application No. 57-110872).
(Refer to Jitsugan No. 57-123565).

The key cap base material 5 in the present invention is a synthetic material in which at least the portion of the transferred surface 6 where cutout characters are formed is light colored, and the other portion is dark colored in the same color as the heat-transferable dye of the colored layer. It is made of resin. The light-colored portion A is a portion that will become a pattern of cut-out characters such as letters and symbols formed on the surface of the keycap, and the dark-colored portion B is a portion that will be the main body of the keycap. The light-colored portion A may constitute the entire surface of the transfer surface 6 (see Figure 2-a), or may constitute a part of the transfer surface 6 (at least the portion where cutout characters are formed). (See Figure 2-b). Furthermore, it goes without saying that when patterns such as letters and symbols are applied to two sides of the key cap base material 5 at the same time, for example, the top surface and the front surface, these two sides may be composed of the light-colored portion A. (See Figure 2-c).

In order to configure the key cap base material 5 of the present invention in this manner, it is preferable to manufacture it by the following method. That is, the so-called unique color molding method involves injection molding a light colored part and a dark colored part using different colored materials.
Alternatively, a light-colored key cap base material is molded by injection molding using a light-colored material, then a resist dyeing layer is formed using an ink with a resist dyeing function on the part where the light-colored part will be formed, and then a dark color is formed. It is preferable to use a so-called resist dyeing method, in which the resist dyeing layer is dyed with a dye, and then the resist dyeing layer is removed. In consideration of workability, productivity, etc., the unique molding method is the most suitable.

In addition, in the present invention, the key cap base material 5
When forming a key cap, a different color molding method is sometimes used. However, unlike the conventional method described above, the different color molding method of the present invention does not require a mold for each pattern. If so,
The same mold can be used,
It is extremely suitable even in the current situation where small lots and a wide variety of products are being produced.

The key cap base material 5 may be made of any material as long as it can be dyed with the heat-transferable dye. Examples include polyethylene terephthalate, polybutylene terephthalate, polycarbonate, triacetate, diacetate, polyether sulfone, aromatic nylon, 66-nylon, polyacetal, and the like.

As the transfer pad 7 used in the present invention, an elastic body such as silicone rubber is used, for example. Further, as the shape of the transfer pad 7, it is preferable to use one having a curved tip.

Next, a method for applying patterns such as letters and symbols to the key cap base material 5 using the transfer sheet 1, key cap base material 5, and transfer pad 7 constructed as described above will be explained.

First, the transfer sheet 1 is placed so that the colored layer 3 and the key cap base material 5 face each other (see FIG. 3). At this time, registration is performed so that the pattern contacts a predetermined position on the surface of the keycap base material 5. At this stage, the colored layer 3 is placed on the surface of the key cap base material 5 and is not in close contact with it.

Next, using the transfer pad 7, the transfer sheet 1 is pressed from the base sheet 2 side to completely bring the surface of the key cap base material 5 and the colored layer 3 into close contact (see FIG. 4).

Thereafter, heat treatment is performed while the surface of the key cap base material 5 and the colored layer 3 are kept in close contact with each other. By doing so, the heat-transferable dye in the colored layer is thermally diffused, and a pattern consisting of cut-out characters 4 such as desired characters and symbols is formed on the surface of the key cap base material 5. Methods for performing heat treatment include a method of pressing using a heated transfer pad 7, and a method of heating the key cap base material 5 in advance (Japanese Patent Application No. 57-145291).
There is a method of placing the key cap base material 5 and the transfer sheet 1 in a heated atmosphere while keeping them in close contact with each other. The heating conditions may be the temperature and time at which the heat-transferable dye thermally diffuses, usually 150°C to 230°C,
It takes about 5 to 60 seconds.

Thereafter, the transfer sheet 1 is peeled off (see FIG. 5).

By doing this, it is possible to obtain a key cap 8 in the color of the dark color part B on which cutout characters 4 in the color of the light color part A are formed (6th
(see figure).

In the above explanation, the cut-out character 4 portions are formed by not applying ink containing a heat-transferable dye to the colored layer 3 of the transfer sheet 1. , the cut-out character 4 portion is expressed by the ground color of the light-colored portion A of the keycap base material 5. However, in the present invention, not only this, but also the above-mentioned cutout character 4
Parts can also be colored in any color. That is, the cutout characters 4 of the colored layer 3 of the transfer sheet 1
By forming the part using an ink containing a heat-transferable dye whose color is darker than the light-colored part A of the key cap base material 5 (see Figure 1-c), the cut-out character 4 part can be formed into any arbitrary shape. It can also be colored.

Furthermore, if there are a plurality of cutout character 4 portions in the colored layer 3 of the transfer sheet 1, it is easy to color each portion in a desired color.

Since the present invention has the above-mentioned structure, it overcomes the drawbacks of the conventional octopus printing method, pouring method, different color molding method, resist dyeing method, etc., namely, abrasion resistance, key touch feel, productivity, fine Key caps with cut-out characters that eliminate all drawbacks such as character reproducibility and have excellent abrasion resistance, that is, dark colors with patterns of light-colored letters and symbols that are highly abrasion resistant. This key cap can be manufactured economically through a simple process, and has extremely high industrial value.

According to the present invention, as described above, it is possible to obtain the effect that light-colored characters, symbols, etc. can be formed on a dark-colored keycap base material. Conventional methods that can form characters, symbols, etc.
That is, by using this method in combination with a transfer printing method using a transfer pad, it is possible to manufacture key caps with all kinds of characters and symbols.

Although the above explanation has been about a method for manufacturing key caps with letters and symbols, the present invention is not limited to key caps as objects to be transferred, but can be applied to various molded products that can be dyed with heat-transferable dyes. Needless to say, it can be applied to

[Brief explanation of drawings]

Fig. 1-a is a cross-sectional view of the transfer sheet according to the present invention, Fig. 1-b is a perspective view of the transfer sheet shown in Fig. 1-a, and Fig. 1-c is a cross-sectional view of the transfer sheet according to the present invention. FIGS. 2-a, 2-b and 2-c are perspective views of the key cap base material of the present invention, and FIGS. 3 to 5 illustrate the manufacturing process of the present invention. The sectional view shown in FIG. 6 and FIG. 6 each show a perspective view of a key cap with characters and symbols obtained by the present invention. In the figure, 1... transfer sheet, 2... base sheet,
3... Colored layer, 4... Cut-out characters, 5... Key cap base material, 6... Transferred surface, 7... Transfer pad, 8... Key cap with letters/symbols, A... Light colored part, B ...Dark colored parts.

Claims (1)

[Scope of Claims] 1. A transfer sheet comprising, on a base sheet, a colored layer in which desired characters, symbols, etc. are formed as cut-out characters using an ink containing a heat-transferable dye; First, by using a synthetic resin molded product in which at least the part forming the cut-out characters is light-colored compared to the color of the heat-transferable dye, and the other parts are dark-colored, which is the same color as the heat-transferable dye, Place the transfer sheet so that the cut-out character part and the light-colored part of the synthetic resin molded product are in contact with each other, and then use a transfer pad to press the transfer sheet from the base sheet side to separate the transferred surface and the colored layer. After that, the transfer sheet is heat-treated while in close contact, and the heat-transferable dye in the colored layer is thermally transferred onto the transfer surface to form desired punched characters on the transfer surface, and then the transfer sheet is A method for manufacturing a synthetic resin molded product with characters and symbols, which is characterized by the removal of characters and symbols. 2. Synthetic resin molding with characters and symbols as set forth in claim 1, characterized in that the cut-out character portions of the colored layer of the transfer sheet are formed by not applying ink containing a heat-transferable dye. method of manufacturing the product. 3. Claims characterized in that the cut-out character portions of the colored layer of the transfer sheet are formed using ink containing a heat-transferable dye that is darker in color than the light-colored portions of the synthetic resin molded product. A method for producing a synthetic resin molded product with characters and symbols as described in item 1. 4. A synthetic resin molded product with characters and symbols as set forth in claim 1, wherein the light-colored part and the dark-colored part of the synthetic resin molded product are produced by a different-color molding method. manufacturing method. 5. The light-colored part and the dark-colored part of the synthetic resin molded product form an anti-dye layer using an ink that has a resist-dye function on at least the part where cutout characters will be formed on the transferred surface of the light-colored synthetic resin molded product. a step of dyeing the synthetic resin molded article with a dye of the same color as the heat-transferable dye of the colored layer; and a step of removing the resist dyeing layer. A method for manufacturing a synthetic resin molded product with characters and symbols as described in item 1. 6. The method for manufacturing a synthetic resin molded product with characters and symbols as set forth in claim 1, wherein the transfer pad is an elastic body exhibiting a convex shape.