| 摘要 |
PURPOSE:To improve light fastness before use and the stability of a developed color image by using a 4-substituted phenylindolylphthalide derivative substituted with an anilino group having a halogen atom at least at the 2-position thereof as an electron donating leuco dye. CONSTITUTION:A compound pref. as a 4-substituted phenylindolylphthalide derivative substituted with an anilino group having a halogen atom at the 2-position thereof is represented by general formula (wherein R1 and R2 are a hydrogen atom, an alkyl group or an aryl group, R3 and R6 are a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a substituted amino group, a hydroxyl group or a nitro group, R4 and R5 are a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a substituted amino group, a nitro group or a cyano group, a ring A is an aromatic ring, R is a halogen atom and n and m are an integer of 1 - 4). The especially pref. ratio of this electron donating leuco dye to be used and an electron acceptive compound is between 1 : 5 - 2 : 3 on a wt. basis. At this time, it is pref. to combinedly use the heat- meltable substances. |
