Patent ID: 8212849

Claim:
A method of manufacturing a thermal head, comprising: forming an opening in at least one of a top surface of a support substrate having a flat-plate shape and a back surface of an upper plate substrate having a flat-plate shape; bonding the back surface of the upper plate substrate to the top surface of the support substrate formed with the opening so as to bring the upper plate substrate and the support substrate into stacked relation; processing a top surface of the upper plate substrate bonded to the support substrate to thin the upper plate substrate to a thickness T; and forming a heating resistor on a region of the processed top surface of the upper plate substrate which opposes the opening, wherein the processing comprises processing the top surface of the upper plate substrate so that a roughness Ra of the top surface of the upper plate substrate satisfies the following expression (1): Ra ≦log e ( T 2 )/(3×10 6 )+6.5×10 −6 (1).