| 摘要 |
PURPOSE:To reduce the magnetic resistance of a magnetic path and contrive a smaller size and higher response characteristic, by intermediately providing a magnetic fluid between a side face of an armature and a surface of a yoke opposed to the side surface. CONSTITUTION:Where a printing head is not printing, a lower surface of the armature 4 is attracted to a core of an electromagnet mechanism, and the gap between the side face of the armature 4 and an auxiliary yoke 2b is filled with a magnetic fluid 7, so that the magnetic resistance of the magnetic path is extremely low, and the armature 4 is attracted to the core more strongly as compared with the case where the magnetic fluid 7 is not intermediately provided. When a coil 9 of the electromagnet mechanism is momentarily energized, the magnetic flux phia present in the magnetic path is canceled, and the armature 4 is released from the core by elastic energy stored in a spring 6. An electric current required for generating a reversely exciting magnetic flux phib can be smaller as compared with that in the case where the magnetic flux 7 is not provided between the side face of the armature 4 and the auxiliary yoke 2b. |
