| 摘要 |
PURPOSE:To keep the whole of yokes at a uniform temperature by a method wherein an inner yoke, an outer yoke, and the connecting part thereof are hollowed, a bottom cover for sealing the hollows is provided, and the hollows are filled with a magnetic fluid. CONSTITUTION:An inner yoke 1 and an outer yoke 3 have hollow inside. The connecting part of the inner yoke 1 and the outer yoke 3 is also hollowed. The hollows are filled with a magnetic fluid 13. A bottom cover 14 is provided on the bottoms of the inner yoke 1 and the outer yoke 3 so as to prevent the leakage of the magnetic fluid 13. When a coil 2 is electrically conducted, the magnetic fluid 13 inside the inner yoke 1 and the outer yoke 3 serves as a magnetic body and is stirred by the longitudinal movement of a printing head. In this manner, the whole of the yokes can be kept at a uniform temperature, and yokes having various kinds of characteristic values can be freely manufactured. |
