THERMAL HEAD

PURPOSE:To obtain a thermal head which prevents oxidation and corrosion of a heat generating resistor, an electrode and improves its heat transfer by filling a defect of a protective layer with inorganic oxide and (or) hydroxide. CONSTITUTION:A thermal head has an insulating board 1, a low thermal conductive layer 2 provided on the board 1, a heat generating resistor 3 provided on the layer 2, an electrode 4 provided on the resistor 3 as well as a protective layer 5 provided on the resistor 3 and the electrode 4. As the protective layer, a material having high thermal conductivity and excellent wear resistance such as silicon carbide, silicon nitride, tantalum oxide, etc., can be employed. Thus, since inorganic oxide and(or) hydroxide is filled in the defect of the layer 5, the protective layer becomes a dense film to shut off invasion of detrimental ions generated from a printing medium, oxygen, moisture in the air into the resistor, the electrode to prevent the oxidation, corrosion of the resistor, the electrode and to prevent an increase in its resistance value.