| 摘要 |
PURPOSE:To uniformize impact forces exerted on a printing medium by wires and prevent nonuniformity in printing from being generated, by adjusting the fitting position of each coil in accordance with the distance between the surface of a platen and the tip of each wire. CONSTITUTION:In accordance with the spacing of each wire 17 from the outer peripheral surface of the platen 3, the fitting position of each coil 9 for each core 8 is adjusted so that a magnetic force acting on an armature 16 corresponding to the wire 17 associated with a smaller value of the spacing is smaller than that acting on an armature 16 corresponding to the wire 17 associated with a larger value of the spacing, whereby a magnetic flux bypassing each of the armatures 16 is adjusted. Namely, the spacing D1 between a tip part of the core 8 and an end part of the coil 9 on the left side in the figure is set to be larger than that D2 on the right side. Accordingly, the impact force exerted by the wire 17 provided on the lift armature 16 is smaller than the impact force exerted by the wire 17 provided on the right armature 16. |
