JP2000094638A - Method for printing in pad transfer type, key top and method for indicating it and printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for printing of a pad transfer type capable of easily increasing a thickness of an ink image to be transferred to a surface to be printed as needed. SOLUTION: Ink 18 is given to a surface of a screen plate 16 having a printing element part 14 corresponding to a printed image, and placed on a flat surface 20a of a flat plate 20. Then, the ink 18 is forcibly passed through the part 14 of the plate 16, transferred to the surface 20a, and an ink image 24 corresponding to a functional indication of the key top 10 is formed on the surface 20a of the plate. Thereafter, a pad 26 is pressed to the surface 20a to transfer the image 24 to a surface 26a of the pad 26. Eventually, a part of the pad 26 carrying the image 24 is elastically urged to a top surface 12 of the top 10 to transfer the image 24 by following to the surface shape. Thus, a functional indication of the sufficient thickness is printed on the surface 12 of the top 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pad transfer printing method capable of printing an image on various surfaces such as a flat surface, a curved surface, and an uneven surface. Further, the present invention relates to a key top having a function sign of a key switch used for an input unit or the like of an electronic device and a method of printing the sign.

[0002]

2. Description of the Related Art As a method of printing images such as characters and symbols on various surfaces such as a flat surface, a curved surface, and an uneven surface, a so-called pad printing in which an ink image carried on an elastic body, that is, a pad surface is transferred to a printing surface. The law is known. In the conventional pad printing method, first, as shown in FIG. 3, ink 3 is applied to the plate surface of an intaglio 2 having an intaglio image portion 1 corresponding to a print image,
After wiping the ink 3 other than the concave image portion 1, the concave image portion 1
The ink image 5 is transferred to the pad surface by strongly pressing the pad 4 made of silicone rubber or the like. Then, of the pad 4,
By elastically pressing the portion carrying the ink image 5 against the printing surface 6, the ink image 5 is transferred onto the printing surface 6 following the surface shape thereof.

The above-described pad printing method is conventionally used in a process of manufacturing a key switch used for an input section of various electronic devices such as a personal computer, a word processor, a push-type telephone, and the like. This is advantageously implemented when printing a function mark such as a character or a symbol on the surface of 3). In this type of key top,
The top surface is formed in a concave curved surface in order to improve the operability with a finger, and the function mark of the key switch is printed on the concave curved top surface. Further, fine irregularities may be formed on the surface of the key top for the purpose of enhancing the operational feeling and designability and suppressing reflected light. According to the pad printing method, it is possible to accurately print a function sign on such a curved surface and a fine uneven surface.

[0004]

In the conventional pad printing method, the thickness (film thickness) of an ink image transferred to a printing surface is determined.
Depends on the depth and width of the intaglio portion of the intaglio, the elasticity of the pad, and the like. However, the elasticity of the pad is generally determined within a range where proper printing can be performed. Therefore, when printing an image of a desired thickness, even if the depth of the concave image portion of the intaglio is made deeper than necessary, the pad can penetrate only to a certain depth in the concave image portion. It is difficult to transfer all the ink in the image area to the pad (see FIG. 3). Due to such restrictions, in the conventional pad printing method, the thickness of the ink image transferred to the printing surface is several tens μm.
It is difficult to increase the thickness as needed.

By the way, in the above-mentioned key top, usually,
Since the function sign is printed on the top surface where the operator's finger contacts, there is a risk that the function sign will be worn out and become unclear during long-term use. In order to eliminate such fears, it is advantageous to increase the ink thickness of the function mark as much as possible to increase the fixing force of the ink to the key top surface. However, as described above, it is difficult to increase the ink film thickness as needed by the conventional pad printing method. Therefore, when the function sign is printed on the key top by the pad printing method, the wear resistance of the function sign is reduced. There is a problem of lack of performance. Further, when the ink film thickness of the function sign is thin, there is a problem that the visibility of the function sign is impaired due to the influence of the color of the key top itself. In addition, when fine irregularities are formed on the key top surface, and the difference in the height of the irregularities is larger than the thickness of the ink image carried on the pad surface, the ink is sufficiently transferred to the fine irregular surface. However, there is a problem that the function display becomes uneven or unclear.

Accordingly, an object of the present invention is to provide a flat surface, a curved surface,
In order to solve the above-mentioned problems in the conventional pad printing method capable of printing images on various surfaces such as uneven surfaces, it is possible to easily increase the thickness of the ink image transferred to the printing surface as needed, and thereby to perform printing. An object of the present invention is to provide a pad transfer type printing method capable of effectively improving the abrasion resistance and sharpness of a printed image. It is another object of the present invention to improve the wear resistance and sharpness of a function indicator printed on the surface of a key top in a key switch used for an input unit or the like of an electronic device.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, an ink image is formed by supplying ink to the surface of a flat plate, and an elastic body is pressed against the surface of the flat plate. The present invention provides a pad transfer type printing method characterized by transferring an ink image to a surface of an elastic body, pressing the elastic body against a printing surface, and transferring the ink image to the printing surface.

According to a second aspect of the present invention, there is provided a pad transfer printing method according to the first aspect, wherein the flat plate is made of an ink-resistant metal material. Claim 3
The invention described in the above, in the pad transfer printing method according to claim 1 or 2, before supplying ink to the surface of the flat plate,
Provided is a pad transfer type printing method for plating a surface of a flat plate.

According to a fourth aspect of the present invention, there is provided a pad transfer type printing method according to any one of the first to third aspects, wherein an ink image is formed on a flat plate surface by a screen printing method. Provide the law. According to a fifth aspect of the present invention, there is provided a key top having a function sign, the function top being printed on the surface by the pad transfer printing method according to any one of the first to fourth aspects. I will provide a.

According to a sixth aspect of the present invention, there is provided a key top sign printing method having a function sign, wherein ink is supplied to the surface of the plate to form an ink image corresponding to the function sign, and the surface of the plate is formed. Pressing the elastic body onto the elastic body, transferring the ink image to the surface of the elastic body, pressing the elastic body onto the keytop, transferring the ink image to the surface of the keytop, and printing the function markings, A sign printing method is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings. In the drawings, the same or similar components are denoted by common reference numerals. Referring to the drawings, FIG. 1 shows a procedure of performing a pad transfer printing method according to an embodiment of the present invention. The pad transfer printing method according to the illustrated embodiment includes a personal computer,
In a manufacturing process of a key switch used for an input unit of various electronic devices such as a word processor and a push-type telephone, a function sign such as a character or a symbol is printed on a concave top surface 12 of a key top 10 made of resin or the like. Shown as a method. However, the pad transfer printing method according to the present invention is implemented as a method of printing images such as characters and symbols on various printing surfaces such as flat surfaces, curved surfaces, and uneven surfaces of printing materials of various other forms. You can do it.

In the pad transfer type printing method according to the illustrated embodiment, first, ink 18 is applied to a plate surface of a screen plate 16 (generally, a gauze and a plate film are adhered to each other) having an image portion 14 corresponding to a print image. , This screen version 16
Is placed on the flat surface 20 a of the flat plate 20. Next, the tip of the squeegee or the doctor blade 22 is slid on the plate surface of the screen plate 16 to forcibly remove the ink 18.
The image is transferred to the surface 20 a of the flat plate 20 by passing through the image portion 14 of the screen plate 16. Thus, an ink image 24 corresponding to the function mark to be printed on the key top 10 is formed on the surface 20a of the flat plate 20.

Next, an elastic body made of silicone rubber or the like, that is, a pad 26 is pressed against the surface 20a of the flat plate 20, and the ink image 24 is transferred to the surface 26a of the pad 26. Finally, the portion of the pad 26 carrying the ink image 24 is elastically pressed against the top surface 12 of the key top 10 which is the surface to be printed, so that the ink image follows the surface shape of the top surface 12. 24 is transferred. In this manner, the function sign is printed on the top surface 12 of the key top 10.

In FIG. 1, the screen plate 16 is shown enlarged in the thickness direction to facilitate understanding, but the actual thickness of the screen plate 16 can be usually selected within a range of several μm to several hundred μm. And therefore the surface 20 of the flat plate 20
The thickness of the ink image 24 formed on a is also several μm to several hundred μ.
m. Then, according to the pad transfer printing method of the present invention, unlike the conventional pad printing method using an intaglio, as shown in an enlarged manner in FIG. By pressing the pad 26 against the flat plate surface 20a, substantially all of the ink image 24 can be transferred to the surface 26a of the pad 26. Therefore, the surface 26a of the pad 26 has several μm
m to hundreds of μm, and as a result, the top surface 12 of the key top 10 has a thickness of several μm to several hundred μm.
It is possible to print a function sign having a desired film thickness in the range of.

As described above, according to the pad transfer type printing method of the illustrated embodiment, only by increasing the thickness of the screen plate 16, the function indication of the key top 10 becomes larger than the ink film thickness obtained by the conventional pad printing method. Can be further increased as necessary. Therefore, the fixing force of the ink image 24 to the top surface 12 of the key top 10 can be increased, and the wear resistance of the function sign can be improved. In addition, by giving a sufficient ink film thickness to the function sign, it is possible to ensure the visibility and the sharpness of the function sign without being affected by the color of the key top itself or minute irregularities on the surface.

In the above embodiment, the flat plate 20
Can be formed from a metal material having resistance to the ink 18 such as melting resistance and corrosion resistance. In this case, the surface 20a of the flat plate 20 may be subjected to a surface treatment such as a plating process in advance. As the ink 18, any ink that can be used in a conventional screen printing method can be used.

[0017]

As is apparent from the above description, according to the pad transfer printing method of the present invention, it is possible to print an image on various surfaces such as a flat surface, a curved surface, an uneven surface and the like. The thickness of the ink image transferred to the printing surface can be easily increased as needed, thereby effectively improving the abrasion resistance and sharpness of the printed image. If the pad transfer type printing method of the present invention is applied to the key top sign printing in the manufacturing process of a key switch used for an input unit of an electronic device, etc., the surface of the key top has excellent wear resistance and sharpness. Function indicators can be printed.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a procedure of performing a pad transfer printing method according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing one stage of an execution procedure of the pad transfer type printing method of FIG.

FIG. 3 is a flowchart showing a procedure for performing a conventional pad printing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Key top 12 ... Top surface 14 ... Image part 16 ... Screen plate 18 ... Ink 20 ... Flat plate 24 ... Ink image 26 ... Pad

Claims (6)

[Claims] 1. An ink image is formed by supplying ink to the surface of a flat plate, an elastic body is pressed against the surface of the flat plate, and the ink image is transferred to the surface of the elastic body. A pad transfer type printing method, wherein the ink image is transferred to the printing surface by pressing a body. 2. The pad transfer printing method according to claim 1, wherein the flat plate is made of an ink-resistant metal material. 3. The pad transfer printing method according to claim 1, wherein a plating process is performed on the surface of the flat plate before supplying ink to the surface of the flat plate. 4. The pad transfer printing method according to claim 1, wherein the ink image is formed on the surface of the flat plate by a screen printing method. 5. A key top having a function sign, wherein the function sign is printed on a surface by the pad transfer printing method according to claim 1. Description: 6. A method for printing a key top having a function sign, comprising supplying ink to a surface of a flat plate to form an ink image corresponding to the function mark, and pressing an elastic body against the surface of the flat plate. Transferring the ink image to the surface of the elastic body, pressing the elastic body against a key top, transferring the ink image to the surface of the key top, and printing the function mark. Sign printing method.