| 摘要 |
PURPOSE:To make it possible to develop color instantaneously at any position on a printed matter which is printed using a discoloring agent without performing coating work. CONSTITUTION:A discolored sheet 2 which is printed using ink containing a discoloring agent which is turned from a colorless state to a colored state by being reacted with color developing liquid 5 and a color developing bag 3 storing therein a sheet-shaped body 7 which is impregnated with the color developing liquid 5 are connected together so as to be folded inwardly. A hole 12 adapted to expose the sheet-shaped body 7 is formed on the surface of the color developing bag 3, which is opposed to an unprinted sheet surface 6B of the sheet 2 when the sheet 2 and the bag 3 are folded inward, so as to be aligned with a discoloring area, and the hole 12 is covered releasably with a cover 13 in liquid-tight manner. |
