PRINTER

PURPOSE:To enable the alignment of a printing head by simple procedure by energizing a head unit in three directions mutually crossing at an almost right angle by a spring in such a state that the head unit and a chassis are closed and engaging the head unit in orthogonal directions by bearings and bringing the head unit into contact with a platen under pressure in the remaining direction among three directions. CONSTITUTION:A head unit 9 and a chassis are made freely openable and closable and, in such a state that both of them are closed, the head unit 9 is energized in respective directions of arrows X, Y, Z mutually crossing at an almost right angle by a spring. In the direction of the arrow X, a bearing 19 is brought into contact with the head unit 9 and, in the direction of the arrow Y, a bearing 23 is brought into contact with the head unit 9. By this constitution, the head unit 9 is fixed at the position on the plane formed by the arrows X, Y. Further, the head unit 9 is brought into contact with a platen under pressure by energizing the head unit 9 in the direction of the arrow Z and its position is spatially fixed. As a result, the detachment and alignment of a printing head is possible by simple procedure.