| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition which facilitates tracking investigation of counterfeit copied matter by blending a colorant, water, an electron-donating color former and an electron-accepting developer. SOLUTION: An ink composition comprises 0.2-7 wt.% of a water-soluble dye or 0.5-25 wt.% of an inorganic or organic dye as a colorant, 0.02-5 wt.% of an electron-donating color former, 0.02-10 wt.% of an electron-accepting developer, 4-30 wt.% of a wetting agent such as ethylene glycol, other components such as a dispersant, a viscosity modifier, an antioxidant and a surfactant, and the balance of water. This composition is applied on a recording medium and the medium is heated at 80 deg.C or more or a pressure of 10 kg/cm2 or more is applied on the medium to develop the desired color. The electron- donating color former includes fluoran-based compounds, phenothiazine-based compounds and triphenylmethane-based compounds. The electron-accepting developer includes phenol resins, novolak resins and salicylic acid derivatives. At least one of the color former or the developer is microencapsulated. |
