Patent ID: 8208211
Filing Date: 2012-06-26
Classification: B82Y,G11B

Abstract:
1. A magnetic transfer device for transferring preformat information carried by a master disk to a magnetic recording layer of a magnetic recording medium by causing close contact between a surface of a transfer information pattern of the master disk and a recording surface of the medium, the transfer information pattern corresponding to the preformat information to be transferred and comprising a ferromagnetic material, and by applying a transfer magnetic field in a direction perpendicular to the surfaces in close contact, the magnetic transfer device comprising: a magnetic field generating structure for applying the transfer magnetic field to a conjoined body comprising the master disk and the magnetic recording medium, the magnetic field generating structure having a pair of permanent magnets and a return yoke, the pair of permanent magnets being arranged such that respective magnetic poles of different polarity of the permanent magnets are opposing, the return yoke being connected to respective other poles of the permanent magnets; a device configured to rotate the conjoined body; and a device configured to move the magnetic field generating structure relative to the conjoined body in a direction of a radius of the conjoined body in a configuration in which the return yoke is positioned radially more outwardly than the pair of permanent magnets in the direction of the radius of the conjoined body, the conjoined body is interposed between the opposing magnetic poles of the pair of permanent magnets and the return yoke, and the magnetic field generating structure is kept at a constant distance from the surfaces in close contact, wherein an inequality holds, wherein M is a length in millimeters in a radial direction of the magnetic field generating structure, X is a number of rotations of the conjoined body in revolutions per minute, and Y is a speed of movement of the magnetic field generating structure from an inner periphery to an outer periphery of the conjoined body.