Method of measuring coercive force of a magnetic card

• US 6,637,653 B1
• Filed: 05/04/2001
• Issued: 10/28/2003
• Est. Priority Date: 11/19/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Sankyo Seiki Seisakusho
• Original Assignee: Kabushiki Kaisha Sankyo Seiki Seisakusho
• Inventors: Takita, Yukihiko, Uemura, Yoshiharu
• Primary Examiner(s): Lee, Michael G.
• Assistant Examiner(s): TRAIL, ALLYSON NEEL
• Application Number:
  US09/831,136
• Time in Patent Office: 907 Days
• Field of Search: 235/449, 235/493, 235/457, 235/380, 235/492, 235/450
• US Class Current: 235/449
• CPC Class Codes: G06K 7/084 sensing magnetic material by relative movement detecting flux changes without altering its magnetised state
• CPC Class Codes: G11B 19/12 by sensing distinguishing features of or on records, e.g. diameter end mark
• CPC Class Codes: G11B 5/00808 magnetic cards
• CPC Class Codes: G11B 5/80 Card carriers

Abstract

A method for judging coercive force of a magnetic card to judge coercive force of a magnetic card to be used. According to the method for judging coercive force of a magnetic card for reproducing or recording magnetic information formed on a low coercive force card or a high coercive force card inserted from a card slot by a magnetic head, after erasing data of an inserted card by an electric current capable of erasing data of only a low coercive force card (step S32), the data of the card is reproduced (step S33), the inserted card is judged as the low coercive force card (step S36) if the data has been destroyed (No at the step S34). Destruction of the data is judged based on the number of times of flux reversal of the reproduced data or by a fact that specific data (STX code) which should be recorded on a predetermined card is not recognized.

Claims

1. A method for judging coercive force of a magnetic card for reproducing or recording magnetic information formed on a low coercive force card or a high coercive force card inserted from a card slot by a magnetic head, wherein after rewriting data of said inserted card by an electric current capable of rewriting data of only said low coercive force card, said data of said card is reproduced, and said inserted card is judged as said low coercive force card if said data has been destroyed.

2. A method for judging coercive force of a magnetic card according to claim 1, wherein destruction of said data is judged by a fact that specific data which should be recorded on a predetermined card is not recognized.

3. A method for judging coercive force of a magnetic card for detecting whether a card inserted from a card slot is a low coercive force card and reproducing or recording magnetic information formed on said card by a magnetic head, wherein after rewriting data of said inserted card by an electric current capable of rewriting data of only said low coercive force card, said data of said card is reproduced, and said inserted card is judged as said low coercive force card if said data has been destroyed.

4. A method for judging coercive force of a magnetic card for detecting whether a card inserted from a card slot is a high coercive force card and reproducing or recording magnetic information formed on said card by a magnetic head, wherein after rewriting data of said inserted card by an electric current capable of rewriting data of only said low coercive force card, said data of said card is reproduced, and said inserted card is judged as said high coercive force card if said data has not been destroyed.

5. A method for judging coercive force of a magnetic card according to claim 4, wherein non-destruction of said data is judged by a fact that specific data which should be recorded on a predetermined card is recognized.

6. A method for judging coercive force of a magnetic card for reproducing or recording magnetic information formed on a low coercive force card or a high coercive force card inserted from a card slot by a magnetic head, wherein after erasing data of said inserted card by an electric current capable of erasing data of said low coercive force card and said high coercive force card, data is written by an electric current capable of writing data of only said low coercive force card, and said inserted card is judged as said low coercive force card if a reproduction state is appropriate when said data is reproduced.

7. A method for judging coercive force of a magnetic card according to claim 6, wherein said appropriate reproduction state of said data is judged based on a number of times of flux reversal of said reproduced data or judged by recognition of specific data which should be recorded on a predetermined card.

8. A method for judging coercive force of a magnetic card for detecting whether a card inserted from a card slot is a high coercive force card and reproducing or recording magnetic information formed on said card by a magnetic head, wherein after erasing data of said inserted card by an electric current capable of erasing data of a low coercive force card and said high coercive force card, data is written by an electric current capable of writing data of only said low coercive force card, and said inserted card is judged as said high coercive force card if appropriate reproduction is impossible when said data is reproduced.

9. A method for judging coercive force of a magnetic card according to claim 8, wherein impossibility of appropriate reproduction is determined when a number of times of flux reversal of a reproduction output is smaller than a usual number of times of flux reversal according to recording density of a magnetic stripe.

10. A method for judging coercive force of a magnetic card for detecting whether a card inserted from a card slot is a low coercive force card and reproducing or recording magnetic information formed on said card by a magnetic head, wherein after erasing data of said inserted card by an electric current capable of erasing data of said low coercive force card and a high coercive force card, data is written by an electric current capable of writing data of only said low coercive force card, and said inserted card is judged as said low coercive force card if a reproduction state is appropriate when said data is reproduced.

11. A method for judging coercive force of a magnetic card according to claim 10, wherein said appropriate reproduction state of said data is judged as appropriate when specific data which should be recorded on a predetermined card is recognized.

12. A method for judging coercive force of a magnetic card for reproducing or recording magnetic information formed on a low coercive force card or a high coercive force card inserted from a card slot by a magnetic head, wherein after erasing data of said inserted card by an electric current capable of erasing data of only said low coercive force card, said data of said card is reproduced, and said inserted card is judged as said low coercive force card if said data has been destroyed, and wherein destruction of said data is judged based on a number of times of flux reversal of said reproduced data or judged by a fact that specific data which should be recorded on a predetermined card is not recognized.

13. A method for judging coercive force of a magnetic card for detecting whether a card inserted from a card slot is a low coercive force card and reproducing or recording magnetic information formed on said card by a magnetic head, wherein after erasing data of said inserted card by an electric current capable of erasing data of only said low coercive force card, said data of said card is reproduced, and said inserted card is judged as said low coercive force card if said data has been destroyed, and wherein destruction of said data is judged-based on a number of times of flux reversal of said reproduced data or judged by a fact that specific data which should be recorded on a predetermined card is not recognized.