Printing Apparatus with Controllable Back Tension on Ink Film and Transfer Film

A printing apparatus for printing images on a transfer film by a transfer operation to transfer ink of an ink film onto the transfer film, comprising:

• four bobbins, wherein one film among the ink film and the transfer film is wound around and stretched between a first bobbin and a second bobbin, while another film among the ink film and the transfer film is wound around and stretched between a third bobbin and a fourth bobbin;
• a platen roller and a thermal head configured to put the ink film and the transfer film into pressed contact, in the transfer operation;
• and
• a driving unit configured to move said one film between the first bobbin and the second bobbin, the driving unit having:
• a motor;
• a first transmission route portion configured to constantly transmit a torque generated by the motor to the first bobbin in a rotational direction according to a rotational direction of the motor;
• and
• a second transmission route portion, branching from the first transmission route portion at a branching portion, configured to selectively transmit the torque to the second bobbin, the second transmission router portion being configured to not transmit the torque to the second bobbin when the motor is rotating in a first rotational direction, and transmit the torque to the second bobbin when the motor is rotating in a second rotational direction opposite of the first rotational direction.