| 摘要 |
PURPOSE:To obtain an impact dot head which is excellent in reliability at low power consumption by a method wherein a form of a core is made thinner as an armature side is being approached. CONSTITUTION:A core part 3a of a base core 3 is opposed to an underside of an armature 2, and a coil 2 is wound around the core part 3a. When S1 for an area of the opposed part of the core part 2a to the armature 2, S2 for an areal circle at a root, H1 for a height from the root to a top, and H2 for a height from the root to a position at which a sectional area of the core part 3a varies are adopted, the title impact dot head is so constructed that formulae of S1/S2=30-80% and H2/H1=20-70% are established. Even through current is made to flow to the coil 10 in a direction of erazing magnetic flux of a permanent magnet 4 during a printing process, since a leak of the magnetic flux of the permanent magnet 4 is little in the core part 3a, it does never occur that leak magnetic flux passe between the armature 2 and the top part of the core part 3a and release of the armature is made insufficient. Therefore, by applying slightly electric energy to the coil 10, the armature 2 can be sufficiently released, and necessary printing quality can be obtained. |
