Bleaching and dyeing; fluid treatment and chemical modification – Diffusion transfer dyeing process – transfer sheet and product – Dry heat treatment for penetration
Patent
1986-10-27
1988-08-16
Clingman, A. Lionel
Bleaching and dyeing; fluid treatment and chemical modification
Diffusion transfer dyeing process, transfer sheet and product
Dry heat treatment for penetration
8470, 101407BP, 156230, 1563099, 1563809, 156541, B41F 1600, B41F 128, B44C 116
Patent
active
047641770
DESCRIPTION:
BRIEF SUMMARY
TECHNOLOGY ASSOCIATED WITH THE INVENTION
The present invention relates to a method of making plastic molded articles having patterns of characters and/or symbols on their top faces and front side faces, and a pattern imparting machine. More specifically, it relates to a method of making plastic molded articles having patterns of characters and/or symbols efficiently and with no misprint, and a pattern imparting machine convenient to use therefor.
BACKGROUND ART
As plastic molded articles requiring patterns of characters and/or symbols on their top faces and front side faces, there are generally many products, a representative example of which is a key cap. This key cap is used in a keyboard of, for example, a push-button telephone, a desk top electronic calculator, a typewriter, a word processor, a personal computer and the like. Hereinafter, reference will be made to the key cap as a plastic molded article for the description of the present invention.
Japanese Laid-open Patent Publication No. 58-155957 discloses a transfer printing method utilizing a transfer pad wherein a transfer sheet used for imparting a picture to various articles is used to form a pattern of characters and/or symbols on a key cap matrix surface by dyeing. That method uses a transfer sheet which is a support sheet on which a pattern of characters and/or symbols are formed by the use of an ink containing thermally migrateable dyes. The transfer sheet is placed on a top face of the key cap matrix with the pattern held in contact therewith. The transfer pad is then pressed from the side of the support sheet of the transfer sheet to cause the pattern to tightly contact the surface of the key cap matrix. A heating treatment is subsequently effected while the key cap matrix surface and the pattern are held in tight contact with each other to cause the thermally migrateable dyes within the pattern to be diffused thermally to form a desired pattern of characters and/or symbols on the surface of the key cap matrix. The support sheet is thereafter removed. Since the pattern of characters and/or symbols is formed by dyeing, this method is effective to provide a product excellent in resistance to wear as compared with a so-called direct printing method and is also effective to provide an inexpensive product as compared with a so-called bicolor molding method, and has, therefore, an extreme utility.
TECHNICAL PROBLEMS
However, the above described conventional method is not intended to impart the pattern of characters and/or symbols simultaneously to the top face and the front side face of the key cap and has the following problems.
Key-caps frequently have a number of functions and, therefore, the necessity has arisen to impart a pattern of characters and/or symbols descriptive of these functions not only to the top face, but also to the front side face of the key cap. However, the conventional method is of such a nature that it cannot cope with the new demand. In other words, even though the conventional method is applied in the form as presented, the pattern of characters and/or symbols cannot be formed simultaneously on the top face and the front side face. Therefore, the use has been currently made of a method wherein, while the conventional method is applied only to the top face, a direct printing method is applied to the front side face. Alternatively, a method is used wherein the conventional method of transfer printing to the top face and a transfer printing step to the front side face are separately performed. However, these methods are disadvantageous in that the productivity is considerably inferior because of the increased production steps. In addition, since no simultaneous imparting of the pattern to the top face and to the front side face can be done, there is a possibility that an error may occur in the combination of the top face pattern and the front side face pattern both required in one key cap.
SUMMARY OF THE INVENTION
The inventors of the present invention have conducted a series of experiments and examination in l
REFERENCES:
patent: 4516978 (1985-05-01), Goto et al.
patent: 4662966 (1987-05-01), Sumi et al.
Inako Yoshihide
Nishida Masahiro
Sumi Takao
Clingman A. Lionel
Nissha Printing Co. Ltd.
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