PURPOSE: To avoid the load fluctuation while the carriage is shifting by mounting the carriage to the first guide bar in a rotatable way and then making the guide wheel provided to the carriage follow the second guide bar.

CONSTITUTION: Carriage 1 is erected, and ink jet head 2 is positioned to oppose to record paper PR on drum 6. Under these conditions, permanent magnet 10 tries to attract iron plate 4a to give the clockwise rotation force to carriage 1. As a result, guide wheel 9 is pressed to second guide bar 4. With the scan driving of carriage 1, wheel 9 is pressed to bar 4 while shifting. Thus, no load fluctuation is caused