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. 15, 1992
Filed:
Sep. 10, 1990
Applicant:
Inventor:
Akira Kawakami, Hino, JP;
Assignee:
Konica Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428336 ; 4284242 ; 4284259 ; 428694 ; 428900 ; 428522 ;
Abstract
A magnetic recording medium is disclosed which comprises a support and, provided thereon, a magnetic layer containing a binder and a back coat layer containing carbon black on the side opposite to the magnetic layer. The magnetic layer contains a copolymer comprising a unit derived from vinyl monomer having sulfonic acid salt group and a unit derived from vinyl carboxylic acid ester having a hydroxyl group, the back coat layer has Ra, an average surface roughness of from 0.010 to 0.035 .mu.m, and not less than 70% by weight of the carbon black has an average particle diameter of from 10 to 30 .mu.m.