| 摘要 |
<p>1416495 Magnetic recording material ARVIN INDUSTRIES INC 29 Jan 1973 [3 Feb 1972] 4470/73 Heading B2E A magnetic recording medium comprises a substrate (e.g. a flexible web) coated with magnetically anisotropic material in a binder, the particles in each of a plurtlity of areas of the medium being circularly oriented, and indicia on the medium locating the centre of each circular area. In a method of making such a recording medium and cutting discs therefrom, the binder 14 is a liquid and the particles 15 are preferable acicular iron oxide, but may be chromium and nickel compounds, and the mixture of the two is spread on a substrate 10 in the form of a flexible web. The web is passed through means 20 for forming a circular magnetic field e.g. circular permanent magnets, electro-magnets or a wire carrying a d.c. current, while the binder is still liquid. The centre of each oriented area is indexed when the field is applied. The binder is then solidified or cured in a drier 30 to form a flexible coating. The discs 40 are then die cut by a die 35 which is aligned by the index marks which may be notches in the side of the web or holes punched at the centre of the circularly oriented areas.</p> |
