中間熱転写印刷のヘッド-ベルト間の接触伝熱状態の解明

Abstract

An indirect thermal transfer printing is capable of printing on both flat and uneven surfaces and is generally used for IC card printer. At present, a transfer unit of the indirect thermal transfer printer has a problem with large power consumption. To overcome this problem a technique of a thermal print head in place of a heating roller currently used has been proposed as power saving technology of the transfer unit of the indirect thermal transfer printer. However, it is difficult to design it because contact heat transfer characteristics between the thermal print head and an indirect transfer belt are not clear. In this study, we simulated the transfer process, and revealed the contact heat transfer characteristics of the thermal print head through evaluation of the temperature distribution and the pressure distribution. First, contact heat transfer coefficients which are dominant parameters in the contact heat transfer characteristics were determined by inverse analysis method. Next, to find out the suitable shape of the thermal print head, three different types of thermal print heads were prepared. The flat thermal print head has shown the most sufficient heat transference to the indirect transfer belt and the heat transfer coefficient decreased in the order of the convex and the concave. However, the manufacturing cost of the concave thermal print head is about one half of those of the other two types. Then, the possibility of improving the heat transference of the concave thermal print head was considered. The heat transference of the concave thermal print head was able to be improved by spreading the concave width.