Printing apparatus including plural printheads and a drive mechanism for the platen rollers

A printing apparatus comprising:

• a thermal recording paper conveyance mechanism which conveys thermal recording paper along a paper conveyance path;
• a first thermal head which is provided along the paper conveyance path, and is arranged to face a first surface side of the paper conveyance path;
• a first platen roller which is arranged to face the first thermal head across the paper conveyance path;
• a first spring that presses the first thermal head toward the first platen roller with a first force;
• a second thermal head which is provided along the paper conveyance path and on a supply side of the thermal recording paper with respect to the first thermal head, and is arranged to face a second surface side of the paper conveyance path;
• a second platen roller which is arranged to face the second thermal head across the paper conveyance path;
• a second spring that presses the second thermal head toward the second platen roller with a second force;
• a drive mechanism that includes a selective torque transmission mechanism that engages a gear mechanism to transmit torque when the first platen roller is rotated in a conveyance direction of the thermal recording paper, and disconnect the torque when the first platen roller is rotated in a reverse conveyance direction of the thermal recording paper, wherein the first platen roller differs from the second platen roller in a feed speed of the thermal recording paper and the second platen roller is exclusively driven by the thermal recording paper when the selective torque transmission mechanism engages the gear mechanism to transmit the torque when the first platen roller is rotated in the conveyance direction of the thermal recording paper.