| 摘要 |
PURPOSE:To equalize the influence of friction between the inner peripheral part and the external peripheral part, by forming a wear-resistant layer on a magnetic recording medium and adopting the structure increasing the thickness of the wear-resistant layer in the external peripheral direction. CONSTITUTION:It is defined that the radius of a track executing the magnetic recording and reproducing of a floppy disc 1 is r(mm.), recording frequency is f(HZ) and the rotating speed per minute of a disc is N(rpm). In addition, d0 and dx show inherent spacing and variable spacing respectively. When the relative loss is fixed and the value is (a), the variable spacing dx is expressed by the following equality. dx=(a.2pirN/54.6.5)-do. In other words, the formation of a recording medium obtained by forming a protective layer 2 as dx on the magnetic recording medium and changing the thickness of the layer 2 in the radius direction of the magnetic recording medium while keeping the relation shown by the equality makes it possible to attain magnetic recording and reproducing fixing the relative loss in the using range. |
