| 摘要 |
PURPOSE:To improve printing quality and besides, to realize low power consumption owing to nearly freedom from influence from magnetic interference, by a method wherein a cylindrical member composed of a magnetic material is provided to an inner perpherty of a core, a coil is wound on outer peripheral surface of the cylindrical member, and current is applied according to the number of simultaneous exciting magnet coils. CONSTITUTION:An inner peripheral ring 11 composed of a cylindrical magnetic material is arranged at a position in contact with an inner periphery of a base plate 2, a bottom end part of the inner peripheral ring 11 comes in contact with the base plate 2, and an upper end part thereof comes in contact with an inner peripheral edge of a side yoke 5. An inner peripheral coil 13 is wound on an outer peripheral surface of the inner peripheral ring 11. Since a loop A composed of the magnetic material is formed, permeance of a magnetic path of a magnet coil 7 becomes extremely large, and an armature 6 can be released only by applying a slight electric energy to the magnet coil 7. When current application time of the inner peripheral coil 13 is varied according to the number of simultaneous exciting magnet coils, a magnetic flux quantity between the armature 6 and a core 1 can be always kept constant, and good printing quality can be obtained owing to nearly freedom from influence from magnetic interference. |
