| 摘要 |
PURPOSE:To execute an erasion without generating a noise, by forming a magnetic pole of a ferromagnetic field on the upstream side in the tape running direction of the head surface, forming a nonmagnetized part adjacently on the downstream side, and forming plural magnetic poles of a gradually reducing magnetic field toward the downstream side from said nonmagnetized part. CONSTITUTION:When a magnetic head device 10 is placed in a position of a full line against a ferromagnetic material 8 and an electric current is made to flow in the prescribed direction to a magnetic coil 15, an S-pole and an N-pole are magnetized and formed to a part 8a and a part 8b, respectively, in the ferromagnetic material 8. Subsequently, when the magnetic head device 10 is moved by length being equal to a magnetic pole array pitch (p) in the direction A, and an electric current whose polarity becomes opposite is made to flow to the magnetic coil 15, the part 8b is opposed to a magnetized effective face 13a, but since the direction of the electric current is reversed, it is magnetized to the N-pole side in the same way as the previous time, and a part 8c opposed to a magnetized effective face 14a is magnetized to the S-pole side. Subsequently, when magnetizing and forming a gradually reducing magnetic field magnetizing part 6 of an erasing head 3, it is executed by varying a quantity of an electric current which is made to flow by reverse-switching it at every intermittent relative movement of the pitch (p) each. In this way, a good erasion by which a residual magnetic flux is converged to zero is executed. |
