Head for thermal printing with stable resistance - obtd. by sputtering a metal boride resistance heating element onto a glazed substrate

摘要

A thermal head consists of a substrate with a resistance heating element on the substrate and electrical conductors to carry the current to the heating element. The resistance heating element consists of a metal boride, pref. Hf, Zr, La, Ta, V, Nb, W, Cr, Ti or Mo borides or their mixts. Alternatively, the heating element contains a metal boride and oxygen. The element may be coated with a layer of SiO2 and/or a protective layer of Ta2O5, Al2O3, MgO, or ZrO2. The substrate pref. consists of a glazed base of a material with good thermal conductivity and a glass layer. On this glazed base is another glass layer consisting of a glass with low alkali content and a softening pt. of 745 degrees C. This glass layer may be quartz. The thermal head is used for the thermal recording of information. The specific resistance of the heating element mah be set to a high value. The head is suitable for high speed printing and has a long operational life.