| 摘要 |
PURPOSE:To reduce the power consumption of an erasing head and stabilize the run of a magnetic tape, by providing a permanent magnet to the erasing head and, at the same time, contacting a dummy member with the magnetic tape at the time of reproduction. CONSTITUTION:The permanent magnet erasing head 8 is equipped with a magnet 8c which is magnetized so as to produce a gradually decreasing alternating magnetic field and a dummy member 8d provided with an arc having a radius of curvature which is almost same as that of the magnet 8c and a center of curvature which is different from that of the magnet 8c as a tape contacting surface and made of a non-magnetic substance, is arranged in a case 8a to be adjusted to the magnet 8c. When the magnet 8c contacts with a magnetic tape 7, the magnetic tape 7 is erased and a picture recording mode is created. In the reproducing mode of a video tape recorder, the case 8a oscillates so as to contact the dummy member 8d with the magnetic tape 7. Therefore, a rotary shaft 9a is rotated by supplying an electric current to a motor only when the mode is switched between the picture recording and reproducing modes. As a result the power consumption is reduced considerably. |
