| 摘要 |
PURPOSE:To prevent discoloring of a recorded image and a background coloring by employing as a leuco dye a specific brown black coloring fluorine compound and a green coloring fluorine compound. CONSTITUTION:A heat sensitive layer contains at least one of brown black coloring fluorine compounds represented by the formulaI, where R1, R2 signify hydrogen, alkyl group, alicyclic group, substituted alkyl group, phenyl group, etc., R3 signifies hydrogen or alkyl group, Xn signifies hydrogen, alkyl group, alicyclic group, phenyl group, etc., m, n signify 0-3, and Ym signifies hydrogen, alkyl, halogenated alkyl group, etc., and at least one of green coloring fluorine compounds represented by the formula II. Red side wavelength of visible spectrum is absorbed by these leuco dyes, thereby approaching to pure black as near as possible, and further preventing discoloring of the recorded image and background coloring. |
