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:
Jul. 11, 1978
Filed:
Jul. 11, 1975
Applicant:
Inventors:
Masashi Somezawa, Sendai, JP;
Shigetaka Higuchi, Sendai, JP;
Tatsuo Shimizu, Tagajo, JP;
Isao Ishibashi, Tagajo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ;
U.S. Cl.
CPC ...
427130 ; 427128 ;
Abstract
A method of preparing a magnetic recording medium, the surface of which has a very smooth magnetic layer. Magnetic paint is coated on a non-magnetic base, which is then passed between calender rolls which comprise a polyurethane roll and a steel roll heated between approximately 40.degree. C. and 200.degree. C. The hardness of the polyurethane roll is greater than approximately 70.degree. in Shore D, and the pressure between the rolls is between approximately 50 Kg/cm and 500 Kg/cm.