| 摘要 |
PURPOSE:To obtain a type head having a simple structure and enabling high speed printing by providing a type needle so as to be protruded by an electromagnetic force acting between a flat plate like wound coil and a leaf spring comprising a good electric conductor adjacent thereto. CONSTITUTION:When impulse electric current is applied to a wound coil from a curent passing terminal 9, secondary current due to electromagnetic induction action is induced to a leaf spring 3 comprising a good electric conductor through a thin insulator 6. If said insulator 6 is extremely thin, said secondary current is formed into current distribution almost equal to that of the wound coil 1 and, moreover, because a direction thereof is reverse, an electromagnetic repelling force is generated between the wound coil 1 and the leaf spring 3 and a type needle 5 attached to a free end of the leaf spring 3 is protruded from a window 8 of a cover 7 to carry out printing. In this case, by selecting the leaf spring 3 from a material with high conductivity and good spring characteristics, a large driving force is instantaneously obtained and, because there is no staturation of the electromagnetic force, high speed printing is enabled. |
