| 摘要 |
PURPOSE:To improve preservation properties by containing 3,4-dihydroxyphenyl- p-tolylsulfonic acid in a compound represented by a given formula as a coloring compound and used as a developing compound. CONSTITUTION:A heat-developing layer is formed by containing 3,4- dihydroxyphenyl-p-tolylsulfonic acid as a developing compound and also containing a compound represented by formula I or formula II as a coloring compound. As the coloring compound, a fluoran compound, a triarylmethane compound, a spiro compound or the like can be used and, for example, 3- diethylamino-6-methyl-7 anilinofluoran or the like can be used. As an example, it is proper to use a developing compound at the ratio of approximately 0.5-10 pts.wt., preferably 1-5 pts.wt., to the coloring compound of 1 pts.wt. |
