In laser dye thermal transfer printing, high resolution and continuous tone images can be easily obtained, since a laser light focuses on a small spot, and its heat energy can be controlled by pulse width modulation. On the other hand, the physical phenomena occur- ring in an ink donor sheet during or just after the laser heating have not bee clarified yet. In this article, the surface of the ink layer consisting of sublimation color dye is heated by microsecond laser pulse irradiation and is observed using time resolve optical micros- copy. The ink layer is deformed during ad after laser pulse irradiation. A small hole is formed as a result of melt and ablation of the ink layer upon laser heating. The diameter of the hole increases rapidly after passing through an induction period, but then the rate of increase slows down. A successful explanation is made of such thermal responses of the ink layer on the time scale of microseconds by assuming Gaussian spatial distribution of laser light intensity and the diffusion of the heat energy by thermal conduction.
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