| 摘要 |
PURPOSE: To obtain heat responsiveness and prevent coloring of a ground by providing, on a support body, a heat sensitive coloring layer which contains a leuco dye which is colorless or has light color at room temperature and an organic acidic substance to be colored in reaction with the leuco dye by heating, and using a compound of a specified naphthol derivative as the organic acidic substance. CONSTITUTION: A leuco dye to be used as a color coupler is of a substance which is colorless or has light color at room temperature and colors in reaction with an acidic substance being heated. For the color coupler, selected one kind or two or more kinds can be used. An organic acidic substance is of a compound of a naphthol derivative to be represented by a formula. In the formula, R represents a 1-4C alkyl group. By using an organic compound having a temperature of 170-230 deg. in a heat sensitive coloring layer as a sensitizer, coloring of a ground under high temperature can be restrained and excellent heat responsiveness at high temperature can be developed, so that excellent high temperature preservability and high temperature coloring property can be obtained. |
