Patent ID: 8009183

Claim:
A thermal printer comprising: a paper housing unit which sets two or more kinds of thermal paper; a paper feeding unit which selectively feeds the thermal paper set in the paper housing unit; a first thermal head which prints one side of thermal paper fed by the paper feeding unit; a second thermal head which prints the other side of thermal paper fed by the paper feeding unit; a first control section which feeds thermal paper from the paper feeding unit, and prints a mark on both sides of the thermal paper with the first and second thermal heads; mark sensors which detects the marks printed by the first control section; a determination section which determines whether the thermal paper fed from the paper feeding unit is double-side thermal paper having a thermosensitive layer on both sides, or one-side thermal paper having a thermosensitive layer on only one side, according to the detection results of the mark sensors; a second control section which selects double-side thermal paper set in the paper housing unit based on the determination result of the determination section, and feeds the paper by the paper feeding unit, at the time of double-side printing; and a third control section which selects one-side thermal paper set in the paper housing unit based on the determination result of the determination section, and feeds the paper by the paper feeding unit, at the time of one-side printing.