The thermal head [A] is pressed against the platen roller [B] only during the master making process. The thermal head position is moved up and down by changing the position of the cam [C]. The cam position is changed by the thermal head pressure release motor [D] via gears. The thermal head pressure release sensor [E] monitors the cam position. The sensor, which is a photointerrupter, is interrupted by the shutter mounted on the gear [F] as the pressure release motor turns to maintain the cam position.
