| 摘要 |
PURPOSE:To obtain a sufficient developed color density, stabilize a developed color image and suppress discoloration with time or by moisture, light or the like, by blending an electron-donative colorless dye with an electron-acceptive compound which is a gallic acid ester derivative. CONSTITUTION:One or more of electron-donative colorless dyes used singly or in combination are dissolved in a solvent such as a synthetic oil and a vegetable oil, and the resultant solution is applied to a base such as a paper and a plastic sheet to produce a color former sheet. On the other hand, one or more gallic acid ester derivatives used singly or in combination or together with other electron-acceptive compound are dispersed in a binder such as a styrene-butadiene latex and a polyvinyl alcohol, and the resultant dispersion is applied to a base such as a paper and plastic sheet to produce a color developer sheet. When the color former sheet and the color developer sheet are brought into contact with each other and a pressure or an impact is exerted thereon, a black image is instantaneously obtained which has high density and excellent resistance to light and heat. |
