| 摘要 |
PURPOSE:To enable the value of resistance of a heating resistor to be stabilized, by forming a protective film in a non-high temperature atmosphere. CONSTITUTION:A heating resistor 6, a common electrode 4, and a discrete electrode 5, which are formed on a surface 3a of a glass glaze layer 3 on an insulating substrate 2, are covered with a protective film 7. The protective film 7 is made of a material, such as Ta2O5, Al2O3, and SiC, by vapor deposition or sputtering. At this time, the insulating substrate 2 prevented from a high temperature decreases the reaction of the forming protective film 7 with the heating resistor 6 and results in a small fluctuation in the value of resistance of the heating resistor 6. When a thermal head 1 conducts printing, the heating resistor 6 comes into contact with a recording paper through the protective film 7 either directly or indirectly through an ink ribbon. The projective film 7 can protect the heating resistor 6, etc., from wearing because it is made of a material having sufficient hardness.
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