PURPOSE: To improve the preservability of a recorded image by adding a specific diazo compound to a thermal recording layer.
CONSTITUTION: A thermal recording material consists of a thermal recording layer containing diazo compound, a compound which generates a coupling component base, or a base due to heating, and a binder on a support. A thermally recording material containing a diazo compound expressed by formula I is formed in said thermal recording layer. In the formula, R1 to R2 are hydrogen atom and a substitution or non-substitution alkyloxy group; R1 to R4 can be the same as or different from each other. R5, R6 are a 1 to 20C substitution or non-substitution alkyl group and aralkyl group. R5, R6 can be the same as or different from each other. R7 is a substitution or non-substitution lower alkylene group. X- is an acid anion. A recorded image formed using a diazo compound expressed by the formula is less susceptible of chromatic fading due to light.
ISHIGE SADAO
TANAKA TOSHIHARU
