PURPOSE: To attain to enhance the anti-wear property and heat conductivity of a polyimide resin used in the protective film of a thermal head, by forming the protective film of a heat generator from the polyimide resin in which a filler comprising a predetermined material is contained in a required wt. ratio.
CONSTITUTION: Fine particles with high hardness comprising silicon carbide or alumina are contained in a polyimide resin for forming the protective layer 4 provided to the heat generator layer 2 of a thermal head as a filler in an amount of 20W50% by wt. of the polyimide resin. Because this polyimide resin is used, high temp. baking can be performed and the anti-wear property and heat conductivity of the polyimide resin used in the protective film of the thermal head is enhanced while the enhancement in printing quality over a long period of time can be achieved.
SHIBATA SUSUMU
SAWAI HIDEO
KUROKI KENJI
