| 摘要 |
PURPOSE:To obtain a dot printer head capable of driving a needle at a high speed, by independently providing a brake part for braking the operation of an armature outside a magnetic circuit in close vicinity to the armature from the attraction surface of a magnetic coil. CONSTITUTION:A needle 22 is driven by the armature 28 revolving in a state magnetically attracted to a magnetic coil 26 and reciprocally moves to perform printing by the leading end thereof. The armature 28 is contacted with a brake part 34 before contacted with the attraction surface 27 of the magnetic coil 26 and a gap is formed between the armature and the attraction surface and no closed circuit is formed between the armature and a magnetic circuit. By this method, the time before the armature is again attracted after was returned to the initial position can be shortened. Because the brake part is independent outside the magnetic field 25, one foot of the magnetic coil can be contacted with the revolution center side of the armature and magnetic efficiency is enhanced and the rising speed of the armature is increased. |
