| 摘要 |
PURPOSE:To ensure that a favorable pure black tone color is constantly formed under any heating condition, by incorporating a diazonium salt, a blue color forming coupler, a yellow color forming coupler and an organic borate all of which are specified respectively. CONSTITUTION:The recording medium is produced by incorporating a diazonium salt of formula [ I ], a blue color forming coupler of formula [II], a yellow color forming coupler of formula [III] and an organic borate of formula [IV]. In the formulas, R1 is 1-4C alkyl or alkoxy, each of R2 and R3 is 1-4C alkyl, X is a paired anion component, n is an integer of 1-18, each of R4 and R5 is 1-18C alkyl or R4 and R5 are groups forming a heterocyclic ring with the nitrogen atom to which they are bonded, each of R6-R9 is alkyl, alkenyl, cycloalkyl, aryl, heterocyclic ring group or cyano, and M is Li or Na. Accordingly, black images with high contrast can be obtained, and the ground density is little changed when the medium is heated after fixing. |
