| 摘要 |
PURPOSE:To erase the magnetism of a magnetic tape automatically by demagnetizing the magnetic tape by moving the tape through the gap between a couple of channel-shaped iron cores wound with coils and by stopping the tape by detecting the tape passing. CONSTITUTION:A couple of channel-shaped iron cores 1 are wound with coil 3 and, while width A of the gap is made greater than the thickness of magnetic tape cassette 2, are arranged opposint to each other. When tape cassette 2 is inserted into gap A with main switch 13 on, microswitch 14 turns on to input the output of transformer 16 to voltage regulator 19. With the output of voltage regulator 20, coil 20 are excited to make contact 18, so that motor 8 rotates. At the same time, demagnetizing coils 3 are excited. Through motor 8, tape cassette 2 passes in the gap to demagnetize the magnetic tape and when cassette 2 moves a prescribed distance away from iron core 1, microswitch 15 is turned off to break contact 18, so that the excitation and motor stop. Therefore, magnetic erasure is automatically carried out. |
