| 摘要 |
PROBLEM TO BE SOLVED: To enable a thermal recording medium to be free from a color change as color develops, and also from a defective discoloration, if exposed to light, and to be light fast, and enable the color development to be securely preserved against heat in a reversibly color forming composition. SOLUTION: This reversibly thermal recording medium consists of an electron-donative coloring compound and an electron-receptive compound as main components and is provided on the support with a recording layer capable of forming a color development and a discoloration relatively depending upon a difference in the heating temperature and/or the cooling speed after heating. In addition, a guanidine derivative shown by formula I and/or vitamins K are added to the recording layer or an adjacent layer to the recording layer. |
