Patent ID: 7561173

Claim:
A thermal printer, comprising: a main body frame; a thermal head swingably mounted to the main body frame; a platen roller disposed to be opposed to a printing surface of the thermal head, for sandwiching a thermal paper with the thermal head to feed the thermal paper; a lock arm swingably mounted to the main body frame, for locking the platen roller with the main body frame by pressing a shaft bearing which rotatably supports the platen roller against the thermal head; a first spring disposed between the lock arm and the thermal head, for biasing the platen roller in a direction in which the platen roller moves toward the thermal head; and a second spring disposed between the thermal head and the main body frame, for biasing the thermal head in a direction in which the thermal head comes into close contact with the platen roller, wherein the first spring is disposed so that the first spring applies a biasing force to the lock arm at a position where the first spring is closer to a swing center of the lock arm than the second spring is.