JP2772571B2 - Magnetic card recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic card recording / reproducing apparatus particularly suitable for recording / reproducing a magnetic card such as a prepaid card used for shopping or the like.

2. Description of the Related Art Conventionally, a magnetic card used as a prepaid card of this type has a large problem when forged, and various countermeasures for preventing forgery have been taken. FIG. 3 of the accompanying drawings schematically shows an example of a magnetic card which has been subjected to counterfeit prevention. This magnetic card 30
A magnetic recording track 33 is provided, and a magnetic ink portion 31 is formed on a part of the magnetic recording track 33 by printing as appropriate. A conventional magnetic card recording / reproducing apparatus for such a magnetic card includes a first magnetic head and a second magnetic head, and reproduces a specific magnetic signal 32 with the first magnetic head. It is determined whether or not the magnetic card is forged, and when it is determined that the magnetic card is forged, predetermined information is recorded and reproduced on the magnetic recording track 33 by the second magnetic head.

Problems to be Solved by the Invention However, in recent years, since a large number of magnetic card recording / reproducing devices are commercially available, anyone can easily obtain a magnetic head, and the conventional magnetic card as described above is used. In combination with a magnetic card recording / reproducing device, by reading a specific magnetic signal or recorded information of the magnetic card, the recorded information of the magnetic card can be easily falsified.

Accordingly, an object of the present invention is to provide a magnetic card recording / reproducing apparatus that cannot easily forge or falsify a magnetic card.

A magnetic card recording / reproducing apparatus according to the present invention includes a first magnetic head and a second magnetic head respectively corresponding to a first magnetic recording track and a second magnetic recording track of a magnetic card, and the magnetic recording track. In the direction along the first
In a state where the magnetic head and the second magnetic head are spaced apart from each other by a predetermined distance represented by a unit of magnetic reversal recorded on the magnetic recording track, each magnetic head is positioned relative to each corresponding magnetic recording track. Magnetic head holding means for holding the first magnetic head and the second magnetic head, so that the first magnetic head reproduces a first specific magnetic signal from the first magnetic recording track. After that, the second magnetic head moves the second magnetic recording track
Determining means for measuring the number of reproduction pulses reproduced by the second magnetic head from the second magnetic recording track to determine the authenticity of the magnetic card until the specific magnetic signal is reproduced; It is characterized by having.

In the magnetic card recording / reproducing apparatus of the present invention, after the first specific magnetic signal of the magnetic card is reproduced by the first magnetic head, the second specific magnetic signal is reproduced by the second magnetic head. By determining that the number of magnetic reversals at intervals up to the predetermined time is within a predetermined range, it is possible to verify whether the magnetic card is valid.

Embodiment Next, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 and 2 of the accompanying drawings.

FIG. 1 is a view showing an arrangement of a first magnetic head, a second magnetic head, and a magnetic card in an embodiment of a magnetic card recording / reproducing apparatus according to the present invention, and FIG. FIG. 1 (b) is a plan view thereof. As shown in FIGS. 1 (a) and 1 (b), the magnetic card recording / reproducing apparatus of this embodiment includes a first magnetic head 1 and a second magnetic head 2. As shown in FIG. 1B, the magnetic card 10 includes a first magnetic recording track 21.
And a second magnetic recording track 22. A first specific magnetic signal 3 formed as a magnetic bar is recorded on the first magnetic recording track 21, and a second specific magnetic signal 4 is recorded on the second magnetic recording track 22. In particular, these magnetic signals have a particularly long magnetic reversal length. Further, as is well shown in FIG. 1A, for example, the first magnetic head 1 and the second magnetic head 2 are magnetically separated by a magnetic reversal interval of 64 ± 2 bits (7.74 ± 0.24 mm at 210 BPI). The recording heads are arranged and mounted on a common base (not shown) forming a part of the magnetic head holding means, separated from the recording track in the extending direction.

The first specific magnetic signal 3 is a recording / reproducing start position.
The second magnetic recording track 22 is provided after the magnetic reversal length of 23 to 104
(A 4-bit random number A indicated by reference numeral 27, in this case,
The number obtained by multiplying the decimal value “3” by “0011” and the constant 40 is 40
) Is recorded, and immediately after that, the second specific magnetic signal 4 is recorded. Further after the second specific magnetic signal 4, a random number A and verification information C = f (A, B) indicated by reference numeral 29 are recorded together with information B indicating a certain value indicated by reference numeral 28. Note that reference numeral 1
0 ′ indicates the magnetic layer of the magnetic card 10.

FIG. 2 shows the first magnetic head 1 described with reference to FIG.
FIG. 1 is a block diagram showing the overall configuration of a magnetic card recording / reproducing apparatus according to the present invention including a second magnetic head 2. As shown in FIG. 2, the first magnetic head 1 includes:
A recording / reproducing circuit 6 is connected, a recording / reproducing circuit 6 'is connected to the second magnetic head 2, and a counter 7 for measuring the number of pulses by magnetic reversal is connected to the recording / reproducing circuit 6'. The recording / reproducing circuits 6 and 6 'further control the transport and recording / reproducing of the magnetic card 10,
CP for judging that the number of pulses generated by the random reversal and the magnetic reversal measured by the counter 7 are within a predetermined range.
U8 is associated. The constants are stored in the memory of CPU8.
Forty are stored.

Next, the operation of the magnetic card recording / reproducing apparatus of this embodiment of the present invention will be described with reference to FIGS.

When the magnetic card 10 shown in FIG. 1 is inserted into this magnetic card recording / reproducing apparatus, and the first specific magnetic signal 3 is detected by the first magnetic head 1, the counter 7 is controlled by the second magnetic head 2. By detecting a pulse signal due to magnetic reversal recorded on the card, measurement of the number of pulses due to the magnetic reversal is started. Immediately after the second specific magnetic signal 4 is detected by the second magnetic head 2, the counter 7 stops counting the number of pulses by magnetic reversal and holds the value as the number of magnetic reversals. The first magnetic head 1 and the second magnetic head 2 are arranged at intervals of a magnetic reversal interval of 64 ± 2 bits and a first magnetic signal after 104 magnetic reversal intervals from the recording / reproduction start position 23. − (64 ± 2) = 40 ± 2 The second magnetic signal 4 is from the recording / reproduction start position 26 to 160
Since it is after the magnetic reversal interval, 160− (40 ± 2) = 120 ± 2 This value is the number of pulses by the magnetic reversal measured by the counter 7. The range of the value of the number of magnetic reversals measured by the counter 7 can be determined by the CPU 8, and if the magnetic card has been tampered with, it can be eliminated as follows.

First, a random number A is reproduced, and a constant 40 is added to the decimal value “3”.
Multiply by That is, 3 × 40 = 120 is obtained. If this value does not coincide with the value measured by the counter 7 within an error range of ± 2, the magnetic card is removed without using it.

To rewrite the recording information of the magnetic card 10 after shopping or the like, a new random number A ', for example, "0100", that is, a decimal "4" is generated by the CPU 8, and the recording / reproducing start position of the second magnetic head 2 is After recording 26 to 200 magnetic reversals (the value obtained by multiplying the constant "40" by the decimal value "4" of the random number A 'and adding 40), the second specific magnetic signal, 2, a random number A 'and verification information C' = f together with valuable information B 'reduced by shopping after the specific magnetic signal
Record (A ', B'). Therefore, when this magnetic card is used in the next shopping or the like, the range of the pulse number measured by the counter 7 is 200- [104- (64 ± 2)] = 160 ± 2.

By the way, suppose that even though the valuable information 28 is reduced by shopping or the like, an attempt is made to illegally rewrite the magnetic card 10 to a state before shopping or the like using a certain magnetic head. However, making the relative position error between the first specific magnetic signal 3 and the second specific magnetic signal 4 to be less than ± 2 magnetic reversals (± 0.24 mm) means that the magnetic head obtained independently (in other words, And the second magnetic head alone), it is very difficult to perform such unauthorized tampering.

Here, the reason for including the 4-bit random number is that the number of magnetic reversals before the second specific magnetic signal 4 is not made as constant as possible, but is changed every time the card is used. It is to pretend not to be. When the number of magnetic reversals is kept constant, a 4-bit random number or the like is not necessary, and after the first specific magnetic signal 3 is reproduced, the second specific magnetic signal 3 is reproduced.
The range of the value of the number of pulses due to magnetic reversal during the reproduction of the second specific magnetic signal 4 by the magnetic head 2 is as follows:
What is necessary is just to store in the memory of CPU8.

Needless to say, the first specific magnetic signal 3 may be formed by a hole other than the magnetic bar, such as a punched hole.
Further, it is desirable that the random numbers be changed between the cards at the time of ticket issuance. The reason why the verification information is recorded on the card is that if only the valuable information B of the magnetic card is altered to B ″ and the verification information remains C = f (A, B), the use of the magnetic card is not performed. Because it can be eliminated.

Further, in the magnetic card 10 in which magnetic layers having different coercive forces described in JP-A-51-129209 are laminated, the magnetic layer having the larger coercive force is used as the recording layer of the first magnetic head. The specific magnetic signal 3 is recorded, and the magnetic layer having the smaller coercive force is used as the recording layer of the second magnetic head 2 to obtain the second specific magnetic signal 4 and information 28 representing a certain value.
Etc. may be recorded.

As described above, according to the present invention, after the first magnetic head detects the first specific magnetic signal of the magnetic card, the second magnetic head detects the second specific magnetic signal. By determining that the number of pulses due to magnetic reversal of the interval until the magnetic card is within a predetermined range, it is possible to verify whether the magnetic card is valid or not. It is generally very difficult to record the magnetic signal of the first specific magnetic signal with a mutual positional error of about ± 0.24 mm or less, so that unauthorized tampering can be more difficult.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a relationship between a first magnetic head, a second magnetic head, and a magnetic card in an embodiment of a magnetic card recording / reproducing apparatus according to the present invention, and FIG. 2 is a magnetic card recording / reproducing apparatus according to the present invention. FIG. 3 is a block diagram schematically showing the overall configuration of the embodiment, and FIG. 3 is a schematic plan view showing an example of a conventional magnetic card. 1 ... first magnetic head, 2 ... second magnetic head, 3 ...
First specific magnetic signal, 4... Second magnetic signal, 5
... Magnetic reversal unit, 6, 6 ′ recording / reproducing circuit, 7 counter, 8 CPU, 10 magnetic card, 21 first magnetic recording track, 22 second magnetic recording track, 23, 26
...... Recording / reproducible start position, 27 ... Random number A, 28 ... Value information B, 29 ... Verification information C

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuyoshi Ito 1-13-1 Nihombashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-63-138525 (JP, A) JP-A Sho 63-86093 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06K 17/00 G06K 19/00-19/18

Claims (4)

(57) [Claims] A first magnetic head and a second magnetic head respectively corresponding to a first magnetic recording track and a second magnetic recording track of the magnetic card; and the first magnetic head and the second magnetic head in a direction along the magnetic recording track. In a state where the two magnetic heads are separated from each other by a predetermined interval represented by a unit of magnetic reversal recorded on the magnetic recording track, each magnetic head is moved relatively to each corresponding magnetic recording track. Magnetic head holding means for holding the first magnetic head and the second magnetic head; and the first magnetic head reproduces a first specific magnetic signal from the first magnetic recording track. 2 The second magnetic head reproduces data from the second magnetic recording track until the second magnetic head reproduces a second specific magnetic signal from the second magnetic recording track. Magnetic card recording and reproducing apparatus characterized by comprising determination means for determining the authenticity of the magnetic card by measuring the number of reproduction pulse. 2. The method according to claim 1, wherein the determining means includes:
3. A recording position rewriting means for rewriting a recording position of the second specific magnetic signal on the second magnetic recording track by using the second recording head.
The magnetic card recording / reproducing apparatus according to claim 1. 3. The method according to claim 2, wherein the recording position of the second specific magnetic signal is rewritten so that the number of reproduction pulses is determined according to the magnitude of the random number to be generated. Magnetic card recording and reproducing device. 4. The magnetic card recording / reproducing apparatus according to claim 3, wherein the verification information created by combining the random number and the value information is recorded on the magnetic card.