Abstract: A thermal print head comprises: a thermally resistant insulating substrate; a glazed glass partially formed on the substrate at one end side thereof; a heating element formed on the glazed glass; a first common electrode formed on the heating element; and a protective film formed on the first electrode; a second common electrode a part of which is formed between the insulating substrate and the glazed glass, the first and second electrodes being connected to each other; wherein the insulating substrate has a chamfer on the one end side where the first and second common electrodes are arranged, the chamfer being formed closely from the glazed glass, a part of the first and second common electrode being arranged on the chamfer.

Abstract: The strength of a join between a ceramic and an associated non-ceramic is determined using an ultrasonic microscope. A converging ultrasonic beam is radiated against a point on a surface of the ceramic, said point being a predetermined distance away from the join between the ceramic and the associated non-ceramic. Data on the intensities of interference waves at respective predetermined variations of the relative distance between a probe of the ultrasonic microscope and the ceramic are collected. The residual stress at the point is calculated on the basis of the cycle of echo intensities of the interference waves for the respective predetermined variations of the relative distance. The strength of the join is then determined on the basis the residual stress.

Abstract: A thermal print head including a glass layer disposed at the edge of a heat resistant substrate, a heat generating element on the glass layer and an electrode for driving the heat generating element disposed both under the glass layer and on the heat generating element is provided. The glass layer is formed of a lower layer of crystallized glass on the electrode and an upper non-crystallized glass portion under the heat generating element. The electrode under the glass layer is formed by print burning a thick conductive film on the substrate from a metal paste having a higher burning temperature than the burning temperature of the glass layers.

Abstract: A thermal print head including a glass layer disposed at the edge of a heat resistant substrate, a heat generating element on the glass layer and an electrode for driving the heat generating element disposed both under the glass layer and on the heat generating element is provided. The glass layer is formed of a lower layer of crystallized glass on the electrode and an upper noncrystallized glass portion under the heat generating element. The electrode under the glass layer is formed by print burning a thick conductive film on the substrate from a metal paste having a higher burning temperature than the burning temperature of the glass layers.