Performances of thermal transfer printing and their improvement by model calculations

The thermodynamic behavior of a thin-film multilayer structure is calculated under stress of a periodical powered electrical heat source. The model is used to optimize the print quality, lifetime, and efficiency of a thermal-transfer printhead. The modeling task involves the adaptation of the printing conditions (pulse power, timing, and mechanical forces) to the thermal and mechanical properties of the printhead, with the aim of good print quality, high printing speed, low power consumption, and a high lifetime of the printhead. The calculations were done in one dimension on the basis of the heat-transfer equation. Numerical solutions were found with Euler´s method, while the material constants were taken from literature. The results are shown to be in good agreement with IR-microscope measurements. The technology has been realised in the Siemens PT 34 thermal transfer page printer