Patent ID: 7876343

Claim:
A thermal printhead comprising: a glaze layer formed on an insulating substrate; a resistor layer formed on the glaze layer; a conductor layer formed on the resistor layer so that part of the resistor layer is exposed to serve as a heating portion; and a protective film formed to cover the conductor layer and the heating portion; wherein the protective film comprises a lower first protective layer, and an upper second protective layer overlapping the first protective layer, the upper second protective layer being an outermost layer; and wherein the first protective layer has a hardness of 500 to 800 Hk and a thickness of 1 to 2 μm, whereas the second protective layer has a hardness of 1000 to 2000 Hk and a thickness of 5 to 8 μm, so that the first protective layer is smaller in hardness and thickness than the second protective layer.