| 摘要 |
PURPOSE:To miniaturize an electric magnet and to decrease its heat-generation by making the diameter of the center yoke of the electromagnet smaller than the length of a recording area and providing a tip yoke in a length corresponding to the recording area on the tip of the center yoke. CONSTITUTION:Around the center yoke 21 in round shaft-shape whose diameter is smaller than the recording length, a coil 22 is wound. On the tip of the center yoke 21, the tip yoke 24 of narrow width which has the length corresponding to the recording length is provided integrally. Since the tip yoke 24 is thus provided, even though the diameter of the center yoke 21 is made thus small, the magnetic field can be supplied over the entire length of recording. In association with that the diameter of the center yoke 21 can be made small, the coil 22 comes also small, hence the whole electromagnet 25 is miniaturized, thus the length of coil 22 is shortened. As a result, the amount of heat generated by its resistance can be reduced. |
