| 摘要 |
PROBLEM TO BE SOLVED: To provide a sheet such as a post card and a greeting card having confidential information which is printed in a non-visible state to keep it confidential and can be visualized for a receiver by a simple means. SOLUTION: Confidential information is applied in a non-visible state by printing mainly comprising a heat-melting wax and/or a thermoplastic resin including micro-capsules containing a photochromic substance transferred from the thermal transfer layer of a thermal transfer ribbon on the surface of a base material. |
