| 摘要 |
PURPOSE:To enable an improvement in durability by brazing a holder and an armature to a spring while increasing the strength and characteristic of the spring in a brazing process, in an impact type dot-matrix printer. CONSTITUTION:The opposite end portion 21a of an armature 21 is positioned between the forked portions 23a and 23b of a holder 20, and the large-diameter portions 22a-22c of a spring 22 are fitted in the respective through holes. Then, a palladium solder is inserted into holes 25a, 25b and 21b, vacuum heat treatment is performed in a vacuum heating furnace to apply solid solution treatment to the spring 22, and thereby re-crystallization and internal stress are removed therefrom. Thereafter an N2 gas is introduced for cooling down, and then brazing and magnetic annealing are applied, so as to increase the magnetic saturation density characteristic of the armature 21. Next, re-heating is made to a prescribed temperature, an aging process is applied to the spring 22 so as to increase the strength and spring characteristic thereof, and then an operating body 9 is formed by cooling. In this way, the durability and reliability thereof can be increased. |
