| 摘要 |
PURPOSE:To increase the magnetic attractive force of an armature and a yoke and also an operating speed by providing a yoke which extends in the inner radial direction beyond the inner radial end of the armature and further, extends in this energizing direction of an armature leaf spring beyond the energizing direction end. CONSTITUTION:The inner ends of legs 25a, 25b, 26a, 26b of yokes 25, 26 are extended to the inner radial end beyond the inner end of an armature 34. In addition, protrusions 26c, 26d which extend further upward beyond the upper end of the armature 34 are provided. The magnetism-coupled area increases by virture of this configuration of the yokes 25, 26 and armature 34 and thereby, the mutual magnetic attraction force can be increased. In the meantime, if a coil 33 is excited, a magnetic flux which is inverted to the orientation of the magnetic flux phi generates, shutting off a magnet ism coupling between an inner leg 22 and the armature 34. Consequently, the armature 34 and in turn, printing wire 36 are displaced in an arrow direction A1 by the spring force of a leaf spring 29 to perform a printing action. If an electric power to the coil 33 is deenergized, the armature 34 is attracted to the inner leg 22 side by the magnetic attraction force of the magnetic flux phi. This process is repeated sequentially to continue the printing action. |
