| 摘要 |
PURPOSE:To operate an armature at a high speed and with limited power consumption by forming a notch with an armature guide on both sides of armatures in such a manner as to be positioned between the fulcrum of rotation and the tip on the needle side. CONSTITUTION:With the energization of a coil 16, an armature 18 is attracted to an attraction surface 27 of a core 17 and rotated on the fulcrum 21 of rotation to perform a dot printing with a needle 11. At this point, as a notch 19 is positioned between the rotation fulcrum 21 of a yoke 15 and the needle 11 side, the facing position between the notch 19 and the yoke 15 is deviated while the magnetic permeability can be heightened with a larger opposed area between the armature 18 and the yoke 15 while the radial distance l3 of the yoke 15 can be reduced, hence lessening the distance l1 from the rotation fulcrum 21 to the center of the attraction surface 27. This also can enlarge the ratio of the distance l2 to the needle 11 side to l1 to allow an action with a small attraction force through a smaller equivalent mass of the armature 18 thereby enabling a high speed operation in terms of the same attraction force. A smaller power consumption is satisfactory enough with a less air gap G. |
