| 摘要 |
<p>PURPOSE:To allow data to be recorded into land deleted from a synthetic resin card repeatedly by partly frosting a smooth layer at higher than a glass transition temperature and lower than a melting point temperature of synthetic resin to form a distorted frost image, or heating the smooth layer at a higher temperature than a frosting temperature. CONSTITUTION:A frosted image 2 such as specified character or symbol is formed in the smooth layer 1 of a card C which has the smooth layer 1 of synthetic resin on at least, part of the surface. The frosted image 2 is formed at higher than a glass transition temperature and less than a melting point temperature of the resin of the smooth layer 1, so that the image 2 has an internal distortion. For this reason, if the smooth layer is heated again, the image 2 disappears and the original smooth surface is restored. In this case, the distortion retained in the frosted image 2 is corrected by heating the card C at a higher temperature than a temperature for frosting, and the image 2 is deleted to restore the original smooth surface. Thus the card can be used repeatedly many times as the frosting and smoothing process is reversible.</p> |
