公开(公告)号：EP0081855A2

公开(公告)日：1983-06-22

申请号：EP82111647.2

申请日：1982-12-15

申请人： MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.

发明人： Miyatake, Norio ,  Uenishi, Mitsuaki ,  Kashimura, Nobuo ,  Ishiwatari, Keizo

IPC分类号： G11B5/127

CPC分类号： G11B5/325 ,  G11B5/00826 ,  G11B5/024

摘要： A permanent magnet type erasing head for generating a gradually decreasing alternating magnetic field in which a plurality of magnetic poles (43-45, 110, 111) are provided along a magnetic recording medium. The first magnetic pole (43, 110) generates a magnetic field of an intensity strong enough to saturate the magnetic recording medium while each of the second and succeeding magnetic poles (44, 111) except the last magnetic pole (45) have a magnetic field with an opposite polarity to that of a preceding magnetic pole and a weaker intensity than that of the preceding magnetic pole.