| 摘要 |
PURPOSE:To provide a high sensitivity, prevent decoloration of image parts or development of ground color from being caused by plasticizer, oil, alcohol or the like and prevent image density from being lowered under pressure in a humid condition, by a method wherein a specified antipyrine complex of zinc thiocyanate is used as a color developer, and an overcoat layer comprising a water-soluble resin as a main constituent is provided on a thermal color forming layer. CONSTITUTION:The thermal color forming layer comprising a leuco dye and a color developer is provided on a base. An antipyrine complex of zinc thiocyanate of the formula is used as the color developer. The overcoat layer comprising a water-soluble resin as a main constituent is provided on the color forming layer. The water-soluble resin used in the overcoat layer is ordinarily a known water-soluble high molecular weight compound in the state of an aqueous emulsion. A water-insoluble resin may be jointly used in the overcoat layer, if required, in which case the amount of the water-soluble resin is preferably not less than 20% based on the total amount of resins in the overcoat layer. |
