| 摘要 |
<p>PURPOSE:To assuredly prevent unjust use by sequentially layering, on a top face of a substrate consisting of non-magnetic body, a magnetic layer consisting of magnetic body having coercive force of a specific range and a magnetic layer consisting of magnetic body with high coercive force and having recorded information which can not be added nor deleted afterward. CONSTITUTION:A magnetic recording medium has a magnetic recording track T. Here, in a cross section taken on line X-X' of the magnetic recording track T, a first magnetic layer 2 consisting of magnetic body having coercive force of 250-4000 oersted is layered on a top face of a substrate 1 consisting of non- magnetic layer. On the top face of the first magnetic layer 2, a second magnetic layer 3 consisting of magnetic body with high coercive force of 4500 oersted or more and having recorded information which can not be added nor deleted afterward is layered. At manufacturing it, the top face of the substrate 1 is coated with required magnetic coating material and dried so as to form the first magnetic layer 2, thereafter, magnetic recording is performed on it. Next, the top face of the first magnetic layer 2 is coated with other magnetic coating material and dried so as to form the second magnetic layer 3.</p> |
