| 摘要 |
PURPOSE:To obtain a multicolor image by a single heating through controlling the temperature of a thermal head, by using a thermal recording sheet coated with a uniform mixture of microcapsules having different color forming temperatures for cyan, magenta and yellow. CONSTITUTION:For example, where cyan, magenta and yellow microcapsules form respective colors respectively at temperatures T1, T2 and T3 (T1<T2<T3), the cyan microcapsules 3 are so designed that a heat-fusible substance provided as a core substance 4 is melted at a temperature of not lower than T1, while a heat-fusible substance forming capsule walls 7 is melted only at a temperature not lower than T2, whereby only the core substance 4 is melted while the capsule walls 7 are not melted at temperature T1, and a cyan leuco dye 5 reacts with a color developer 6 to form a cyan color. Similarly, the magenta microcapsules 3 form a magenta color at temperature T2, in which case the capsule walls of the cyan microcapsules 3 are melted, and the cyan dye developed into the cyan color reacts with a decolorizing agent 8, whereby the developed cyan color is removed. Accordingly, when dots of the thermal head 9 are brought to temperatures T1, T2 and T3, the microcapsules 3 on the thermal recording sheet 1 corresponding to the dots are melted, and the respective colors are developed, thereby forming a multicolor image. |
