Patent ID: 7929005

Claim:
A thermal printer, comprising: a case main body; a thermal head fixed to a side wall of the case main body; a platen roller mounted for undergoing rotation about a rotational center thereof to feed heat sensitive paper, the platen roller confronting a printing surface of the thermal head so that the heat sensitive paper is fed between the platen roller and the thermal head; a swing arm mounted to the case main body for undergoing swinging movement about a swing center of the swing arm; a slider rotatably supporting the platen roller and mounted to a front end of the swing arm for undergoing linear movement on a plane including the rotational center of the platen roller and the swing center of the swing arm; an engagement piece provided to one of the slider and the case main body; an engagement concave portion provided to the other of the slider and the case main body for engagement with the engagement piece to hold the swing arm in a swing radius direction of the swing arm at a position where the platen roller confronts the printing surface of the thermal head; a chamfer portion formed in one of the engagement piece and the engagement concave portion for causing the slider to move when the engagement concave portion engages the engagement piece; and biasing means for biasing the slider in an outward direction of the swing radius direction of the swing arm such that the engagement piece engages the engagement concave portion and the platen roller pressurizes the heat sensitive paper against the printing surface of the thermal head in a state in which the heat sensitive paper is fed between the platen roller and the printing surface of the thermal head.