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:
Feb. 08, 1994
Filed:
Oct. 11, 1990
Hideaki Tanaka, Katsuta, JP;
Kenichi Gomi, Hitachi, JP;
Shoichi Sawahata, Hitachi, JP;
Maki Kondo, Sendai, JP;
Masaki Ohura, Odawara, JP;
Norikazu Tsumita, Hiratsuka, JP;
Katuo Uda, Kanagawa, JP;
Yoshiki Kato, Tokyo, JP;
Yoshihiko Miyake, Odawara, JP;
Toyoji Okuwaki, Tokyo, JP;
Noriaki Okamoto, Ibaraki, JP;
Nobuo Nakagawa, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
There is provided a magnetic disk apparatus including at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate; a magnetic head which faces the magnetic disk in a rotating state with a micro gap and is supported by a slider; rotating means for rotating the magnetic disk; and magnetic head positioning means for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein a plurality of protrusions each having a flat surface are formed in at least a region on the surface of the magnetic disk where a contact start/stop operation can be executed, an area ratio of the protrusions per 1 mm.sup.2 lies within a range from 0.1 to 80%, a height of the protrusion of the maximum height among the protrusions lies within a range from 5 to 40 nm, and the magnetic layer is formed on the whole surface on the base plate. According to the above magnetic disk apparatus, the frictional force between the disk and the head is small, and the floating height of the head can be reduced, and good floating stability is obtained, so that excellent recording and reproducing characteristics are obtained.