Patent ID: 7425973

Claim:
A thermal type image forming apparatus for printing images on both sides of a medium, which are a first surface and a second surface, by rotating a thermal print head (TPH) about a platen roller to a first position facing the first surface of the medium and to a second position facing the second surface of the medium, the thermal type image forming apparatus, comprising: a transfer unit for transferring the medium in a first direction to supply the medium between the platen roller and the thermal print head and in a second direction substantially opposite to the first direction to perform printing; a control member for controlling movement of the platen roller in the second direction to align a printing nip formed by the platen roller and the TPH with a heating line of the thermal print head, the control member including a first control portion for controlling movement of the platen roller in the second direction when the thermal print head is located at the first position; and a second control portion for controlling movement of the platen roller in the second direction when the thermal print head is located at the second position; and a bias member elastically biasing the platen roller to contact the control member.