| 摘要 |
PURPOSE:To prevent the leakage of the magnetic flux and miniature the printing head by employing a composite half-hard core in which a half-hard magnetic member equivalent to the permanent magnet is integrated with a half-hard magnetic member smaller in coersive force than the magnetic member. CONSTITUTION:The magnet coil 4 is arranged around the composite half-hard core 13 in which a half-hard magnetic member 13 large in coersive force enough to act as permanent magnet and a half-hard magnetic member 13b smaller in coercive force are integrated like a concentric wire material or in a multi-layer sheet. The magneic member 13a is maintained constant and with the energization of the coil 4, the magnetic field larger in coersive force than that of the magnetic member 13b is inverted from the position to the negative. When the magnetic member 13b coincides the magnetic member in the magnetizing direction, the plate spring 7 is attracted while when they are different in coersive force, the attraction is released from the sprint to drive the printing wire 8. Thus, the dot printing is done by the wire 8. |
