| 摘要 |
PURPOSE:To improve the durability of a protective membrane and minimize the possibility of disconnection of a common electrode by directly covering the surface of a hard layer in the section opposed to the ribbon edge of an ink ribbon with a protective coat. CONSTITUTION:The exposed surfaces of the substrate 1, glazed layer 2, heat generating element 4, common electrode 5 and discrete electrode 6 of a thermal head are covered with a protective coat 7. The common electrode 5 reaches the top of the glazed layer 2 on both ends of a thermal resistor 3 except the section opposed to the edge part 9 of an ink ribbon 8. Then a thermal resistor layer 3 is completely covered with the coat. On the other hand, the common electrode 5 reaches the mid-part of the glazed layer 2 in the section opposed to the edge part 9 of the ink ribbon 8. Then the thermal resistor layer 3 at the top of the glazed layer 2 is caused to be exposed. After this, the edge part 9 of the ink ribbon 8 slides to the protective coat 7, resulting in the concentration of a load on the protective coat 7. Since the hard thermal resistor layer 3 and the glazed layer 2 exist below the protective layer 7, the protective coat 7 is not deformed. |
