PURPOSE: To make the speed and acceleration of a driving wire uniform, and improve the durability and printing quality by a method wherein a current value which is added to a coil at an electromagnetic driving part and a pattern minimum cross sectional area of copper foil, etc., in a substrate are respectively, separately set while considering a counter force which generates at positioning of a wire.

CONSTITUTION: When one wire or a plurality of wires are selected, based on a printing command signal, a uniform voltage is added to a copper foil pattern in a substrate 3, magnetic force generates by a coil 8, a suction surface 17 of a lever 2 is attracted to the core surface 18 of a frame 7, the wire springs out, and an ink on an ink ribbon 19 is transferred on a printing paper, and thus printing is performed. In this case, by setting a minimum cross sectional area for respective wire by changing the minimum width dimension of the copper foil pattern, of which thickness is uniform, in the substrate 3, a speed and acceleration by which a wire 1 is driven are totally made the same. That is because even when totally the same voltage is added to a plurality of identical coils 8, since the minimum cross sectional areas of the copper foil pattern 16 are respectively set to a suitable one, and a resistance value of the copper foil is changed, and thus currents which flow to respective identical coils 8 are changed, therefore, the strength of magnetic force of respective electromagnetic driving parts can be changed.