JPH043281A - Magnetic card recording/reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic card recording and reproducing apparatus particularly suitable for recording and reproducing magnetic cards such as prepaid cards that are used for shopping and the like.

BACKGROUND OF THE INVENTION Conventionally, magnetic cards used as prepaid cards of this type pose a serious problem if they are counterfeited.
Various measures have been taken to prevent counterfeiting. FIG. 3 of the accompanying drawings schematically shows, in plan, an example of a magnetic card provided with anti-counterfeiting measures. This magnetic card 30 has a normal magnetic recording track 33, and further has an appropriate number of magnetic ink portions 31 printed on a portion thereof, which are used as magnetic bars to generate a specific magnetic signal 32. are doing. A conventional magnetic card recording/reproducing device for such a magnetic card includes a first magnetic head and a second magnetic head, and the first magnetic head reads the specific magnetic signal 3.
2 to determine whether the magnetic card is a forgery, and if it is determined to be legitimate, the second magnetic head records and reproduces predetermined information on the magnetic recording track 33. That's what I do.

Problems to be Solved by the Invention However, in recent years, a large number of magnetic card recording and reproducing devices have become commercially available, and anyone can easily create a magnetic head by hand. In combination with a magnetic card recording and reproducing device, it has become possible to easily falsify the recorded information on the magnetic card by reading specific magnetic signals and recorded information on the magnetic card.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic card recording/reproducing device that prevents magnetic cards from being easily forged or tampered with.

Means for Solving the Problems A magnetic card recording/reproducing device according to the present invention includes a first magnetic head and a second magnetic head that respectively correspond to a first magnetic recording track and a second magnetic recording track of a magnetic card, and With the first magnetic head and the second magnetic head spaced apart from each other by a predetermined interval represented by the unit of magnetic reversal recorded on the magnetic recording track, each magnetic head a magnetic head holding means for holding the first magnetic head and the second magnetic head so that the first magnetic head and the second magnetic head are moved relative to the recording track; After reproducing a specific magnetic signal, before the second magnetic head reproduces a second specific magnetic signal from the second magnetic recording track, the second magnetic head reads the second magnetic recording track. The present invention is characterized by comprising a measuring means for determining the authenticity of the magnetic card by measuring the number of reproduction pulses reproduced from the track.

Function: In the magnetic card recording/reproducing device of the present invention, after the first magnetic head reproduces the first specific magnetic signal of the magnetic card, the second magnetic head reproduces the second specific magnetic signal. It is possible to verify whether or not the magnetic card is legitimate by determining that the number of magnetic reversals in the interval before the magnetic card is within a predetermined range.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be described in more detail with reference to embodiments of the invention with reference to FIGS. 1 and 2 of the accompanying drawings.

FIG. 1 is a diagram showing the arrangement of a first magnetic head, a second magnetic head, and a magnetic card in an embodiment of a magnetic card recording/reproducing device according to the present invention, and FIG. 1(a) is a partially cutaway elevation view of the magnetic card. 1(b) is a plan view thereof. These Figure 1 (
As shown in a) and (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. 1 et al., the magnetic card 10 is
A first magnetic recording track 21 and a second magnetic recording track 2
2. A first specific magnetic signal 3 formed as a magnetic bar is recorded in the first magnetic recording track 21, and a second specific magnetic signal 4 is recorded in the second magnetic recording trunk 22. Specifically, these magnetic signals have a particularly long magnetic reversal interval. Furthermore, as best shown in the first effl(a),
For example, the first magnetic head l and the second magnetic head 2 are 6
Magnetic reversal interval of 4 bits and 2 bits (for 2108PI, 7,
74 t 0.24 mm) along the direction of extension of the magnetic recording trunk on a common base (not shown) forming part of the magnetic head holding means.

The first specific magnetic signal 3 is at a recording/reproduction start position 2
3 to 104 magnetic reversal major axes, and the second magnetic recording track 22 includes tracks from a recording/reproduction start position 26,
For example, 160 (4-bit random number A indicated by reference numeral 27)
1 Here, a magnetic reversal section 5 of "0011" (a value obtained by multiplying the decimal value "3" by a constant 40, plus 40) is recorded, and immediately after that, a second specific magnetic reversal section 5 is recorded. Signal 4 is recorded. Further after the second specific magnetic signal 4, there is a random number A, verification information C=f (A, B
) are recorded. Note that reference numeral 10' indicates a magnetic layer of the magnetic card 10.

FIG. 2 is a block diagram showing the overall configuration of a magnetic card recording/reproducing apparatus according to the present invention, which includes the first magnetic head 1 and the second magnetic head 2 described with reference to FIG.

As shown in FIG. 2 of 2, a recording/reproducing circuit 6 is connected to the first magnetic head 1, and a recording/reproducing circuit 6 is connected to the second magnetic head 2.
A recording/reproducing circuit 6' is connected to the recording/reproducing circuit 6'.
A counter 7 that measures the number of pulses due to magnetic reversal is connected to the recording/reproducing circuits 6 and 6'.Furthermore, the recording/reproducing circuits 6 and 6' control the conveyance of the magnetic card 10, record/reproduce, generate random numbers, and perform measurements by the counter 7. A CPU that determines that the number of pulses due to magnetic reversal is within a predetermined range.
8 is associated. Note that a constant 40 is stored in the memory of the CPU 8.

Next, the operation of the magnetic card recording/reproducing apparatus according to this embodiment of the present invention will be explained with reference to FIGS. 1 and 2.

When the magnetic card 10 shown in FIG. 1 is inserted into this magnetic card recording/reproducing device and the first specific magnetic signal 3 is detected by the first magnetic head 1, the counter 7 is By detecting the pulse signal caused by the magnetic reversal recorded on the card, the measurement of the number of pulses caused by the magnetic reversal is started. As soon as the second specific magnetic signal 4 is detected by the second magnetic head 2, the counter 7 stops counting the number of pulses due to magnetic reversal, and holds the value as the number of magnetic reversals. The arrangement interval between the first magnetic head 1 and the second magnetic head 2 is a magnetic reversal interval of 64±2 bits, and since the first magnetic signal is present after 104 magnetic reversal intervals from the recording/reproduction start position 23, -(64±2)=40 output 2 The second magnetic signal 4 is 1 from the recording/reproduction possible start position 26
Since it is after 60 magnetic reversal intervals, 160-(40±2)
=120±2 This value is the number of pulses due to magnetic reversal measured by the counter 7. The range of the number of magnetic reversals measured by the counter 7 can be determined by the CPU, and if the magnetic card has been tampered with, it can be eliminated as follows.

First, reproduce the random number A, and set the constant 4 to its decimal value "3".
Multiply by 0. That is, find 3×40=120. If this value and the value measured by the counter 7 do not match within an error range of =2, the magnetic card is rejected without being used.

To rewrite the recorded information on the magnetic card 10 after shopping, etc., the CPU 8 inputs a new random number A', for example, °0100.
”, that is, the decimal number “4” is generated, and the second magnetic head 2 generates 200 pieces from the recording/reproduction start position 26 (the number obtained by multiplying the decimal value “4” of the random number A′ by the constant 40). 4
After recording the magnetic reversal of 0 (plus 0), a second specific magnetic signal is generated, and further after this second specific magnetic signal, a random number A' is generated together with valuable information B' that has been deducted due to shopping, etc.
, verification information C' = f (A', B') is recorded. Therefore, when this magnetic card is used for the next shopping, etc., the range of the number of pulses planned by the counter 7 is 20 (1-'104- (64±2); -160=2).

Incidentally, suppose that an attempt is made to illegally rewrite the magnetic card 10 using a certain magnetic head to the state before the purchase or the like, even though the valuable information 28 has been reduced due to the purchase or the like. However, it is possible to create a relative position error between the first specific magnetic signal 3 and the second specific magnetic signal 4 to be less than the magnetic reversal (±0.24 mm) of the magnetic head 2 by hand alone. (In other words, since it is extremely difficult to use the second magnetic head alone), such unauthorized tampering becomes even more difficult.

Here, the reason for including the 4-bit random number is to keep the number of magnetic reversals before the second specific magnetic signal 4 as constant as possible.
This is to make it appear that this magnetic reversal interval has no meaning by changing it each time the card is used. When making the number of magnetic reversals constant, a 4-bit random number is not necessary, and after the first specific magnetic signal 3 is reproduced, the second specific magnetic signal 4 is reproduced by the second magnetic head 2. The range of the number of pulses due to magnetic reversal during reproduction is expressed as CPt
All you have to do is store it in the J8's memory.

Note that it goes without saying that the first specific magnetic signal 3 may be formed using a punched hole or the like other than the magnetic bar. Furthermore, it is desirable to vary the random numbers between cards when tickets are issued. 1. The verification information was recorded on the card by
Even if only the valuable information B on the magnetic card is tampered with B'', if the verification information remains C-f (A, B),
This is because the use of the magnetic card can be eliminated.

Further, in a magnetic card 10 in which magnetic layers having different coercive forces are laminated, which is described in Japanese Patent Application Laid-open No. 51-129209, the magnetic layer having a larger coercive force is used as the recording layer of the first magnetic head. A specific magnetic signal 3 is recorded, and the magnetic layer with the smaller coercive force is transferred to the magnetic head 21a
A second specific magnetic signal 4, information 28 representing a certain value, etc. may be recorded as the recording layer.

Effects of the Invention 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. It is possible to verify whether the magnetic card is legitimate by determining that the number of pulses due to magnetic reversal in the interval until it is detected is within a predetermined range.
Since it is generally very difficult to record a second specific magnetic signal with a relative position error of less than about 0.24 mm relative to the first specific magnetic signal, unauthorized falsification is only possible. It can be difficult.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the 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. FIG. 3 is a block diagram schematically showing the overall configuration of the embodiment. FIG. 3 is a schematic plan view showing an example of a conventional magnetic card. I...first magnetic head, 2...first magnetic head, 3...first specific magnetic signal, 4...second magnetic signal, 5... -Magnetic reversal unit, 6.6'...Recording/reproducing circuit, 7...Counter, 8...CPU, 0...Magnetic card, l...First magnetic recording track, 2...Second magnetic recording track, 3.26...Recording/reproduction possible start position, 7...Random number A, 8...Value information B, 9...Verification information C0th Figure 1 (a) Card movement direction (b)

Claims (2)

[Claims] (1) A first magnetic head and a second magnetic head respectively corresponding to the first magnetic recording track and the second magnetic recording track of the magnetic card, and the first magnetic head and the second magnetic head in the direction along the magnetic recording track. such that each magnetic head is moved relative to each corresponding magnetic recording track with a predetermined interval between the head and the magnetic recording track represented by a unit of magnetic reversal recorded on the magnetic recording track; a magnetic head holding means for holding the first magnetic head and the second magnetic head; and after the first magnetic head reproduces a first specific magnetic signal from the first magnetic recording track, the second magnetic head The number of reproduction pulses that the second magnetic head reproduces from the second magnetic recording track is measured until the head reproduces the second specific magnetic signal from the second magnetic recording track, and the number of reproduction pulses reproduced from the second magnetic recording track is measured. 1. A magnetic card recording/reproducing device comprising: determination means for determining the authenticity of a magnetic card. (2) The determination means causes the second magnetic head to rewrite the recording position of the second specific magnetic signal on the second magnetic recording track each time the magnetic card is used. The magnetic card recording and reproducing apparatus according to claim 1, further comprising a replacement means.