New Type Thermal Printing Head Using Thin Film

This paper describes the development of a new type thermal printing head. The main features of this paper are as follows. 1) The heating element is a Ta
2
N thin-film resistor coated with a SiO
2
-Ta
2
O
5
double layer. The SiO
2
layer prevents oxidation of Ta
2
N; the Ta
2
O
5
layer, which rubs directly against the heat-sensitive paper, is hard enough to resist abrasion. 2) A theoretical calculation revealed that the thermal time constant can be controlled by changing the thickness of the heat insulating layer. It was found that a glazed alumina ceramic substrate has the most suitable thermal properties. 3) A beam-lead diode array and a crossover structure have been developed to satisfy the electrical interface requirements of both the thermal printing head and the external logic.