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. 23, 1986
Filed:
Dec. 13, 1982
Norio Miyatake, Kobe, JP;
Mitsuaki Uenishi, Neyagawa, JP;
Nobuo Kashimura, Katano, JP;
Keizo Ishiwatari, Kobe, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A magnetic erasing head for erasing a magnetic recording media such as magnetic tape. The device has a head surface defined to make sliding contact with the tape surface. The head surface includes a permanent magnet material and a high permeability material. The permanent magnet material defines the portion of the head surface extending from the inlet side toward the exit side thereof for the sliding tape and is magnetized to include portions which have alternate polarities and which have a field strength which gradually decrease from the inlet side to the exit side of the head surface. The high permeability material defines a portion of the head surface with a predetermined length from the exit side toward the inlet side and with a width of about one-half of the recording track of the tape. The high permeability material is positioned substantially in alignment with the center of the recording track. Thus, the magnetic tape erased by the erasing head does not induce secondary harmonic distortion due to mutual cancellation of residual magnetism.