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.

Date of Patent:
Oct. 23, 1990

Filed:

May. 27, 1988
Applicant:
Inventors:

Toshio Ono, Kanagawa, JP;

Hiroshi Ogawa, Kanagawa, JP;

Chiaki Mizuno, Kanagawa, JP;

Shinji Saito, Kanagawa, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428213 ; 427131 ; 428323 ; 428329 ; 428336 ; 428408 ; 428694 ; 428900 ;
Abstract

A magnetic recording medium is described, comprising a nonmagnetic support having thereon a first magnetic layer and having on the first magnetic layer a second magnetic layer, in that order, said second magnetic layer comprising a magnetic particle, a binder, abrasive particles and carbon black having an average primary particle diameter of 80 m.mu. or more, said first magnetic layer comprising a magnetic particle, a binder and carbon black having an average primary particle diameter of 40 m.mu. or less without substantially containing abrasive particles in the first magnetic layer, and the thickness ratio of the first layer to the second layer, first layer thickness/second layer thickness is 1.8 or more.


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