US Patent 7782349 Thermal printer and method of controlling the same

A thermal paper sheet having heat-sensitive layers on a first surface and a second surface having a front-and-rear relationship is prepared. A first thermal head which comes into contact with a front surface of this thermal paper sheet and a second thermal head which comes into contact with a rear surface 1b of the same are provided. Further, printing data input from the outside is divided into first printing data and second printing data. The thermal heads are driven in accordance with the printing data.