| 摘要 |
PURPOSE:To obtain an image expressing gradations with favorable fidelity over a wide range, by using a substance of a specified structural formula as a gradation-controlling agent in a thermal recording medium comprising a heat-fusible ink component which contains a heat- fusible substance, a coloring agent and the gradation-controlling agent as main constituents. CONSTITUTION:A gradation-controlling agent incorporated in a heat-fusible ink component is one of compounds of structural formulas I-III, wherein R1 is H, a subst. or unsubst. alkyl or subst. or unsubst. aryl, each of R2 and R3 is a subst. or unsubst. alkyl, alkoxyl, halogen or nitro, and n is 0, 1, 2, 3 or 4. The grdation-controlling agent, a coloring agent and a holding material are mixed and dispersed together with an organic solvent to obtain an ink dispersed liquid (or solution). Separately, a solution obtained by dissolving a resin in an organic solvent is mixed with the ink dispersed liquid, and the mixture is uniformly dispersed in an intimate mixer. A dispersed liquid thus obtained is applied to a base, followed by drying to obtain a heat-fusible ink layer having a fine structure. According to the magnitude of thermal energy applied to a thermal transfer medium having the ink layer, an ink exudes through a porous resin structure and through a network structure of a filler to be transferred onto the surface of a receiving sheet. Therefore, by controlling the thermal energy applied at the time of transfer, a transferred image having excellent gradation expression can be obtained. |
