| 摘要 |
PROBLEM TO BE SOLVED: To provide an invisible information printing sheet from which invisible information is impossible to see, of which the invisible information printing portion is hard to color with abrasion in ordinary handling, in which the invisible information can be easily visualized by rubbing with a nail and which is free from shavings on the occasion of visualizing the invisible information, enables attainment of a clear colored image particularly on the occasion of visualization and moreover is so processed as to suppress unjust reading of the information. SOLUTION: The invisible information printing sheet is formed by a method wherein portions to be printed respectively by using two or more kinds of scratch coloring inks containing an electron donating dye precursor, an electron accepting compound and varnish are provided on the same side of a substrate. COPYRIGHT: (C)2009,JPO&INPIT |
