The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 11, 1990
Filed:
Nov. 19, 1986
Youichi Hayata, Odawara, JP;
Michihiro Matsui, Odawara, JP;
Fuji Photo Film Co., Ltd., Minami-ashigara, JP;
Abstract
A magnetic recording medium such as a magnetic recording tape or disk is demagnetized by applying a saturating magnetic field to the magnetic recording medium, then applying an unsaturating magnetic field to the magnetic recording medium in a direction opposite to the direction of the saturating magnetic field, and finally applying an alternating magnetic field to the magnetic recording medium to remove residual magnetism which has been produced on the magnetic recording medium by the unsaturating magnetic field. The saturating, unsaturating, and alternating magnetic fields are generated respectively by a first DC erasing head, a second DC erasing head, and an AC erasing head, which are arranged at spaced intervals in the order named in the direction in which the magnetic recording medium is continuously moved.