Patent ID: 8313258

Claim:
A printing apparatus comprising: a first thermal head which is arranged to come into contact with one of surfaces of thermal recording paper; a first platen roller which faces the first thermal head across the thermal recording paper; first biasing means for pressing the first thermal head against the first platen roller; a platen roller gear which is rotated while being integral with the first platen roller; a second thermal head which is arranged on an upstream side of the first thermal head in a paper feed direction to come into contact with the other surface of the thermal recording paper; a second platen roller which faces the second thermal head across the thermal recording paper; second biasing means for pressing the second thermal head toward the second platen roller; a motor; and a power transmission mechanism which transmits rotation of the motor to the platen roller gear, wherein the power transmission mechanism includes: a driving gear which is rotated by the motor; and an idler gear which is arranged to be coaxial with the second platen roller and is relatively rotatable with respect to the second platen roller, and engages both the driving gear and the platen roller gear to transmit rotation of the driving gear to the platen roller gear.