Patent ID: 7369337

Claim:
A magnetic field application apparatus for initially magnetizing a slave medium and/or for reversing magnetization thereof in magnetic transfer of a signal pattern onto the slave medium, wherein the magnetic transfer is performed by initially magnetizing the slave medium in a predetermined direction, by placing the slave medium and an original disk for transfer in close contact with each other after initial magnetization and by applying a magnetic field in a direction opposite to that of initial magnetization so as to reverse magnetization of the slave medium based on a pattern on a surface of the original disk for transfer, the apparatus comprising: a pair of magnetic field application means, each of which is arranged, at least during application of a magnetic field, on either side of a magnetic field application target so as to face each other, and which generate a magnetic field in a desired direction, wherein each of the magnetic field application means includes a pair of magnetic portions which generate a magnetic field in a desired direction from one of the magnetic portions toward the other magnetic portion, and of which the polarities on the side facing the magnetic field application target are different from each other, wherein each of the magnetic portions is formed so that magnetic force applied to the magnetic field application target becomes weaker stepwise or continuously from the side of the magnetic portion, facing the other magnetic portion, toward the opposite side thereof, wherein each magnetic portion of the pair of magnetic portions includes a plurality of magnets which are arranged so that magnetic force applied to the magnetic field application target becomes weaker from the side of the magnetic portion, facing the other magnetic portion, toward the opposite side thereof.