| 摘要 |
PROBLEM TO BE SOLVED: To prevent forgery of data, etc., for showing the using state, etc., by performing one-directional magnetical recording. SOLUTION: A part of a recording surface 11 of a prepaid card 10 is made to be a one-directional recording area 13 by using a magnetic material capable of magnetic recording only under the demagnetizing state at ordinary temp., and is moreover divided into a 1st recording area 131 and a 2nd recording area 132 , and at the manufacturing time, the one-directional recording area 13 is initialized into the demagnetizing state. At the time of issuing the card, a specific data for this card is recorded in the 1st recording area 131 , and also the specific data is recorded in a reading commencement part of the 2nd recording area 132 . Then, whenever the card is used, the data recorded in the 1st and 2nd recording areas 131 and 132 are read out and collated after demagnetizing an already recorded part out of the one-directional recording area 13. Afterward, a frequency data showing used frequency is additionally recorded in the 2nd recording area 132 . |
