THE DEVELOPMENT OF DIRECT THERMAL FULL-COLOR RECORDING MATERIAL

To obtain a full-color image by a direct thermal recording method, int roduction of a fixing process into the thermal recording is indispensa ble. This is so, because an image printed by low thermal energy is dis turbed by the high thermal energy applied for another color. We studie d the fixing methods of thermal images and came to the conclusion, tha t the method utilizing a diazonium salt compound as a color forming ma terial is the best. A thermal recording image is photofixed by the dec omposition of unused diazonium salt compound. Utilizing this key techn ology, we have developed a new direct thermal full color recording pap er named ''Thermo-Autochrome paper'' which produces high resolution, p hoto-quality print with vivid color and rich tonal gradation.