| 摘要 |
<p>PURPOSE:To permit printing of printing dot periods of 0.9-0.6m.sec. by providing a projected graze layer containing SiO2 and B2O3 partly on a base plate and also providing a heating resistor and a conductor on the graze layer. CONSTITUTION:In printing, a voltage occurs between conductors 4a and 4b and an electric current flows in a heating resistor 3 to electrically energize the resistor 3. The heat so generated is partly conducted to a protective film 5 and then to a recording paper and partly conducted to a graze layer 6 and then to an alumina base plate 1. In the case of printing of printing dot periods of 0.9- 0.6m.sec., the surface temperature of the thermal head becomes 550-650 deg.C. The graze layer 6 contains 80-95% SiO2 and B2O3 in all in a proportion of 8:1, and therefore, the softening temperature of the graze layer 6 becomes 700- 800 deg.C. No melting of the graze layer occurs during the printing operation.</p> |
