| 摘要 |
<p>PURPOSE:To contrive the improvement of the printing speed of a thermal head by making a thin metallic film layer located farther from a base sheet lower in fusing point than a thin metallic film layer located near the base sheet. CONSTITUTION:A prepaid card C is formed by stamping out the material consisting of a base sheet 1 coated with a colored layer 2, an anchor layer 3 coated on the surface of the colored layer 2, a first thin metallic film layer 4 evaporated onto the anchor layer 3, a second thin metallic film layer 5 evaporated onto the surface of the first thin metallic film layer 4 and a protective layer 6 formed on the surface of the second thin metallic film layer 5. At this time, the bismuth (Bi) having a purity of 99.99% and a film thickness of 100 Angstrom is evaporated as the first thin metallic film layer 4 and the tin (Sn) having a purity of 99.99% and film thickness of 1000 Angstrom is evaporated as the second thin metallic film layer 5. Since in this way the thin metallic film layer 5 located farther from the base sheet 1 is made lower in fusing point than the metallic film layer 4 located near the base sheet, the thermal responsiveness of the two thin metallic film layers is improved and the fusing reaction rate is increased relative to the heating control by a heat printing means such as thermal head, thereby improving the printing speed.</p> |
