| 摘要 |
PROBLEM TO BE SOLVED: To prevent a magnetic card from being forged or altered and to eliminate a noise component by performing magnetic writing to a magnetic recording medium with a cyclic signal corresponding to a signal recording density higher than the signal recording density of the magnetic recording medium. SOLUTION: A magnetic layer 3 of a magnetic card 1 has a one-time recording track (issue information track) 4 and a read/write track (use actual result track) 6h5. On the one-time recording track 5, issue information is recorded at the time of issuance; and then an M magnetic body 4a records contents with a very high holding force and a high-holding recording magnetic body 4b holds and records the contents. The read/write track 5 is erased with a DC magnetic field at the time of issuance; and an M magnetic body 5a has a very high-holding force to disable and invalidate magnetic rewriting and a high-holding recording magnetic body 5b has high-holding recording information erased and then has no information recorded. Thus, magnetic writing to the magnetic recording medium with a cyclic signal corresponding to a signal recording density higher than the magnetic recording density is performed. |
