| 摘要 |
PURPOSE:To enhance the fixing sensitivity, resolving power, shelf stability, etc. by forming 3-layer structure composed of a basic substance generating layer contg. a Co (III) ammine complex, a specified polynuclear quinone and a specified chelating agent, a specified middle layer and a color developing layer contg. a specified oxidizable leuco body, etc. CONSTITUTION:On support 1, basic substance generating layer 2 is formed consisting essentially of a Co (III) ammine or amine complex, a redox couple of a polynuclear quinone showing absorption in the 400-550nm wavelength region and a hydrogen donor, and a chelating agent showing slight absorption in the visible region when it coordinates to Co. Layer 2 is coated with middle layer 3 made of water- soluble resin or emulsion resin, and on layer 3 color developing layer 4 or the like is formed consisting essentially of oxidizable leucoaminotriarylmethane, an acid promoting color development, hexaarylbiimidazole which is converted into a photooxidizing agent for the leuco body when it absorbs ultraviolet rays, and a polymer binder having repeating units each contg. a carbonyl group and capable of forming carbinol amine by reaction with NH3 or amine. The polymer binder is cross-linked and hardened to inhibit the color development of the ground part. |
