| 摘要 |
PURPOSE:To make a hammer drive mechanism applicable onto a high speed dot printer which does not produce much heat, by making slits approximately in parallel with the direction of magnetic flux flowing through a core, thereby reducing eddy current occurring in the core when a hammer is driven and improving energy efficiency of a hammer drive mechanism. CONSTITUTION:A leaf spring is normally attracted to a core 5 by magnetic force of a permanent magnet 1 and bent. When current is fed to a degaussing coil 7, as required, magnetic force of the permanent magnet is cancelled to release the leaf spring 6 so as to move a print pin 9 by the energy stored in the leaf spring 6 thus printing onto a paper through an ink ribbon. When there are slits 4 in the direction approximately in parallel with the magnetic flux flowing through the core 5, electrical resistance is increased by the slits made in the path of eddy current upon supply of current to the degaussing coil 7 thereby eddy current is reduced. The permanent magnet 1 is sandwitched by a yoke 2 and a base yoke 3 to which the core 5 having slits 4 approximately in parallel with flux flowing from the permanent magnet 1 is welded. |
