Title:
DEMAGNETIZING METHOD FOR ANNULAR RECORDING MEDIUM LAYER WITH OUTER PERIPHERY OF ROTOR
Document Type and Number:
Japanese Patent JPS5914350
Kind Code:
A
Abstract:
PURPOSE:To eliminate noise by locally heating an annular recording medium layer while rotating a rotor, applying a magnetic field by an erasure head, thereby effectively erasing the magnetization only at a resin magnet and eliminating the remaining magnetization simultaneously magnetized in a motor. CONSTITUTION:A resin magnet 1 and a permanent magnet 4 of a reocrding medium layer attached onto the outer periphery of a rotor are simultaneously magnetized. Then, a section 6 of thicknesswise direction of the magnet 1 is heated by heating means 7. In this case, a rotor is rotated, and locally heated to the vicinity of Curie temperature by heating means 7. At this time, an erasing magnetic field is simultaneously applied by an erasure head 8. In this manner, only the magnet 1 part is demagnetized.
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Inventors:
KAMINAKA NOBUMASA
Application Number:
JP12230482A
Publication Date:
January 25, 1984
Filing Date:
July 13, 1982
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H02K21/14; G11B15/54; H01F13/00; H02K15/03; (IPC1-7): G11B15/54; H02K21/06; H02K21/14
Attorney, Agent or Firm:
Toshio Nakao