| 摘要 |
PURPOSE:To surely erase the magnetic recording with inexpensive constitution by forming the upperstream side of an erasure gap of an erasure head by a magnetic material having a high saturated magnetic flux density and the downstream side by a magnetic material having a lower saturated magnetic flux density. CONSTITUTION:A magnetic material having a high saturated magnetic flux density is coated to a base 10 at the floppy disk upperstream side of an erasure gap 4 to form a magnetic film 11 and a magnetic material having a lower saturated magnetic flux density than that of the film 11 is used to the downstream side of the gap 4 to form a magnetic layer 12. Through the constitution above, the strength of the magnetism around the gap 4 sufficiently exceeds the strength Hs required for erasure and the attenuation of the magnetic field at the outside of the gap 4 is gradual, in other words, the distance between points M and N is long. When a magnetic medium passes through the part from the right toward the left, the medium is magnetically saturated between the points L and M, while passing through the points M, N, the magnetic hysteresis curve is gradually narrowed and finally converged to the point zero of the hysteresis curve. That is, the nearly complete erasure is attained.
|
