PRINTING SYSTEM AND PRINTING CHARACTERISTICS OF LASER-DYE THERMAL TRANSFER USING A HIGH-POWER LASER

In laser dye transfer printing, the small laser spot provides high res olution, but the printing speed is relatively low compared to that of thermal head printing, in which a large number of dots can be recorded simultaneously. To shorten the printing time, a compact high-power Nd :YAG laser is used for the light source in our printing system. We hav e developed a practical laser dye transfer printing system with a newl y developed Nd:YAG laser and compact optical head. Printing characteri stics with a short pulse, of the order of 1 mu s, are evaluated in thi s printing system. As a result, continuous-tone printing with a pulse of 2 mu s is feasible when laser power is 1.0 W, indicating a signific ant advance in printing speeds. The transfer efficiency as a function of pulse width has a peak that can be observed. A thick ink layer prod uces maximum optical density, although a reduction in efficiency resul ts from increasing the layer thickness. Good halftone printing is also performed using this system.