| 摘要 |
PURPOSE:To obtain a high speed printer enhanced in the heat transfer and radiation effect of a yoke member and imparting high printing quality by allowing the inner peripheral wall of a metallic yoke member to be adjacent to an exciting coil corresponding to the outer shape thereof as close as possible within a range not becoming insulation inferiority. CONSTITUTION:A yoke member 3 is composed of a magnetic material having a bottomed cylindrical shape and integrally formed along with the coil core 3a arranged to the inner surface thereof in a ring form and constituted of the outer peripheral parts 3b-3e of the yoke member 3 adjacent to the outer peripheral contour of the exciting coil 4, which is wound around the coil bobbin 18 mounted to the coil core 3a, as close as possible. When a current is applied to one or plural exciting coils 4 selected by a printing order signal, the magnetic flux flowing through the bottomed cylindrical yoke 5 and a side yoke 6 from the coil core 3a through the yoke member 3 is opposed to the coil core 3a to flow in the armatures 8 having a ferromagnetic property provided on both sides of a drive lever 7 and the drive lever 7 is attracted to the coil core 3a to revolve in a clockwise direction. The printing wire 10 held to the leading end of the drive lever is allowed to impinge against recording paper 20 through an ink ribbon 19 to perform printing. |
