JPH08263834A - Magnetic card and recording-reproducing device therefor - Google Patents

Abstract

PURPOSE: To prevent alteration by regulating the Curie temp. of a 1st magnetic layer having high coercive force to 100-200 deg.C and the reproduction output of a 2nd magnetic layer having low coercive force to 1/10-1/2 of that of the 1st magnetic layer. CONSTITUTION: A 1st magnetic layer 3a having high coercive force, a 2nd magnetic layer 4a having low coercive force and a protective layer 5 are laminated on a plastic substrate 2a to obtain the objective magnetic card 1a. The coercive force of the 1st magnetic layer 3a is higher than that of the 2nd magnetic layer 4a, the coercive force of the 1st magnetic layer 3a is 7-15kOe at ordinary temp. and that of the 2nd magnetic layer 4a is 200Oe to 6kOe at ordinary temp. The Curie temp. of the 1st magnetic layer 3a is 100-200 deg.C. Altenation with a conventional recording-reproducing device can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic card suitable for applications such as credit, CD (cash dispenser), ID (authentication), in which information is not rewritten under normal use, and a recording / reproducing apparatus thereof. In particular, the present invention relates to a magnetic card that cannot be tampered with by a conventional magnetic card recording / reproducing apparatus and its recording / reproducing apparatus, and a magnetic card and its recording / reproducing apparatus that have little adverse effect on recorded information even when a strong magnetic field such as a high magnetic force magnet approaches.

[0002]

2. Description of the Related Art A conventional magnetic card erases or rewrites information on the magnetic card and invalidates the subsequent use of the magnetic card when the personal identification numbers do not match in order to prevent unauthorized use. However, since information can be tampered with by the conventional recording / reproducing apparatus, there is a possibility that the recorded information on the magnetic card, from which the information has been erased or rewritten, is rewritten into a usable state and is illegally used. Furthermore, there is a risk that an unauthorized card may be used by reading the information on a proper magnetic card and copying this information to another magnetic card.

On the other hand, if the recorded information on the magnetic card is erased or rewritten by a simple mistake such as a mistake in the personal identification number, the card is reissued in order to resume use. Moreover, the coercive force of the conventional magnetic card is 2
Since it is from 00 Oe to 3 kOe, the information is easily erased when the stop magnet or the magnetic clip of the handbag or the eyeglass case approaches. Even when the magnetic card becomes unusable due to such an erasing accident, the magnetic card is reissued in the same manner.

Japanese Unexamined Patent Publication No. 6-187636 discloses a magnetic recording medium in which two magnetic layers having different Curie temperatures and coercive forces are laminated, and a magnetic layer having a high coercive force and a magnetic layer having a low coercive force are different. A method has been proposed in which two pieces of information are recorded, the magnetic layer having a low coercive force is erased at the time of reproduction, and information is read only from the magnetic layer having a high coercive force. In this case, in order to read the information recorded in the magnetic layer having a high coercive force, it is necessary to erase the magnetic data in the magnetic layer having a low coercive force, which cannot be processed by the conventional recording / reproducing apparatus.
Further, in order to invalidate the use, a recording / reproducing device that rewrites information in the magnetic layer having a high coercive force is required.

[0005]

Therefore, the present invention eliminates the need to prevent tampering, to invalidate the use of a magnetic card that has been tampered with, and to reissue a magnetic card that has been invalidated due to a mismatch in personal identification numbers. And the recorded information can be read even if it is accidentally brought close to the high magnetic force magnet, while the information can be recorded by heating it near the Curie temperature. Therefore, it is an object of the present invention to provide a magnetic card and a recording / reproducing apparatus for the same, in which recording for performing a procedure for invalidating the use of the card is possible even with a conventional recording / reproducing apparatus having no heating means.

[0006]

In order to achieve the above object, the present invention is a magnetic card in which two magnetic layers having different coercive forces in a predetermined state are laminated on a substrate, and the first magnetic layer has a high coercive force. Curie temperature of the layer is 100 ℃ or more 20
The reproduction output of the second magnetic layer having a low coercive force in the range of 0 ° C. or lower is 1/10 or more of the reproduction output of the first magnetic layer 1
It is characterized by being in the range of / 2 or less.

In the recording / reproducing apparatus of the present invention for recording information on the magnetic card, when the same information is recorded on the first and second magnetic layers, information is recorded by a magnetic field generated from the magnetic head by the recording current Ia. To enable recording, first the first magnetic layer is once heated to around the Curie temperature, and then the temperature of the first magnetic layer is lower than the Curie temperature due to contact with the magnetic head or natural heat dissipation. Information is recorded by the magnetic head while the coercive force of the first magnetic layer is lowered. It should be noted that the recording current Ia is set in a range not less than a value at which sufficient recording can be performed on the second magnetic layer.

On the other hand, when recording is performed only on the second magnetic layer, recording is performed by the recording magnetic field of the magnetic head generated by the recording current Ib which does not affect the recording information on the first magnetic layer.

Further, in the recording / reproducing apparatus, a lamp is used as a means for heating the first magnetic layer, and the magnetic card is heated by the lamp light in a non-contact manner. Further, in order to erase the information recorded on the second magnetic layer and the information illegally recorded on the conventional magnetic card, the recording / reproducing having the magnetic field generating means in the range where the recorded information on the first magnetic layer is not lost. Provide a device.

[0010]

The information recorded in the first magnetic layer having a high coercive force of the magnetic card of the present invention has almost no demagnetization even when the magnetic card approaches the high magnetic force magnet, and the second magnetic layer having a low coercive force. Even if the information recorded in (1) is erased, the information in the first magnetic layer remains, so that the information can be read. Further, in the case where the same information is recorded in the first and second magnetic layers, or in the state where the information is recorded in the first magnetic layer and the second magnetic layer is erased, even in the conventional read-only machine. Information can be read. Further, in the conventional recording / reproducing apparatus having no heating means, the information in the first magnetic layer cannot be rewritten, and tampering can be prevented.

On the other hand, when the conventional recording / reproducing apparatus is used to rewrite the information of the magnetic card in which the information is normally recorded, the rewritable outputs are only the first and second magnetic layers. Information recorded on the two magnetic layers is mixed, and correct information cannot be obtained, and the magnetic card can be invalidated. If there is a discrepancy in the personal identification numbers and there is a suspicion of illegal use, by recording only on the second magnetic layer,
Similarly, the readable output is a mixture of the information recorded on the first and second magnetic layers, and the subsequent use of the magnetic card can be invalidated. Further, since the original information remains in the first magnetic layer, it is possible to manufacture a reusable magnetic card by erasing only the second magnetic layer.

On the other hand, to a fraudulent card in which the information of the magnetic card of the present invention is directly copied onto the conventional magnetic card, a magnetic field within a range in which the recorded information of the first magnetic layer is not lost is applied to the illegal card. Although the information on the magnetic card cannot be unreadable, the information on the unauthorized card is erased and the information cannot be read, thus preventing unauthorized use.

[0013]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a partial sectional view of an embodiment of a magnetic card according to the present invention. Magnetic card 1 according to the present invention
a is a first magnetic layer 3a having a high coercive force and a second magnetic layer 4 having a low coercive force on a substrate 2a made of a plastic material.
a and the protective layer 5 are laminated. Either of the first magnetic layer 3a and the second magnetic layer 4a may be laminated on top. In order to record information in a state in which the first magnetic layer 3a having a high coercive force is heated and the coercive force is lowered, in order to improve the heating efficiency, as shown in FIG. The second magnetic layer 4a is preferably provided on the upper layer. The magnetic layer is preferably formed by a coating method, but is not particularly limited to a vapor deposition method, a sputtering method, a plating method, or the like.

The coercive force of the magnetic layer is higher in the first magnetic layer 3a than in the second magnetic layer 4a, the coercive force of the first magnetic layer 3a is 7 kOe or more and 15 kOe or less at room temperature, and the second magnetic layer 4a.
Has a coercive force of 200 Oe or more and 6 kOe or less at room temperature,
The Curie temperature of the first magnetic layer 3a is 100 ° C. or higher and 200.
The range below ℃ is desirable. When the Curie temperature is lower than 100 ° C., the magnetic characteristics are greatly deteriorated when the temperature of the magnetic card rises due to being left in an automobile or the like, and the output is likely to be reduced due to demagnetization. When the Curie temperature is higher than 200 ° C., when the first magnetic layer 3a is heated around the Curie temperature, thermal deformation easily occurs due to the heat resistance of the plastic material used for the card substrate, and the magnetic layer and There is also a problem that the protective layer 5 is thermally deteriorated. The Curie temperature of the second magnetic layer 4a is not particularly limited, but as with the first magnetic layer 3a, 100 ° C. or higher is desirable so that the deterioration of the magnetic characteristics when the temperature of the magnetic card rises is reduced. If the coercive force of the second magnetic layer 4a is less than 200 Oe, it becomes difficult to retain the recorded information for a long period of time, and if it exceeds 6 kOe, it becomes difficult to record with a conventional recording / reproducing apparatus.
Above 6 kOe is desirable. The first magnetic layer 3a is shown in FIG.
And an example of the material of the magnetic powder of the second magnetic layer 4a, the Curie temperature, the coercive force, and the reproduction output ratio (relative value).

FIG. 3 is a conceptual diagram showing the basic structure of the magnetic card (the protective layer is omitted) and the magnetic card recording / reproducing apparatus according to the present invention. The recording / reproducing apparatus is the first of the magnetic card 1a.
A halogen lamp 6a is provided as a lamp for heating the magnetic layer 3a in a non-contact manner, and a magnetic head 7a using a sendust alloy as a core material. The halogen lamp 6a can be heated immediately after it emits light, does not require warming-up time required for other heating methods such as a heat roller and a thermal head, and operation such as holding high temperature during standby, and the surface of the magnetic card compared to the contact heating method. Has the advantage of not scratching. The magnetic head 7a includes a first magnetic layer 3a and a second magnetic layer 4a,
A recording magnetic field of 4 kOe to 5 kOe is generated. As the core material of the magnetic head 7a, in addition to Sendust alloy, Fe
Any one of —Ni type alloy and Fe—Co type amorphous alloy, or a material having equivalent characteristics may be used.

The operation of the magnetic card and the magnetic card recording / reproducing apparatus according to the present invention will be described with reference to FIG. The halogen lamp 6a of the recording / reproducing apparatus is caused to emit light, and the Curie temperature (15) of the first magnetic layer 3a of the magnetic card 1a is
(0 ° C) around 140 ° C to 160 ° C. After that, the first magnetic layer 3a is cooled to a temperature lower than the Curie temperature by contact with the magnetic head 7a or natural heat dissipation. Since the amount of temperature decrease due to contact with the magnetic head 7a is particularly large, the magnetic head 7a is replaced by a PTC thermistor (not shown in the figure).
Then, the temperature is raised from 50 ° C. to 70 ° C. in advance. As a result, variation in temperature of the first magnetic layer 3a is suppressed and stable recording characteristics can be obtained as compared with the case where the temperature of the magnetic head 7a is not raised. Further, since the temperature decrease of the first magnetic layer 3a can be alleviated and the heating temperature of the first magnetic layer 3a by the halogen lamp can be set low, the thermal damage of the magnetic card can be reduced. The coercive force of the temperature-raised first magnetic layer 3a is kept in the range of 200 Oe to 4 kOe where the magnetic head 7a can record information and record information, and in this state, the recording current Ia is passed to the first magnetic layer 7a. Information is recorded on the first magnetic layer 3a. At this time, the same recording magnetic field is applied to the second magnetic layer 4a. Second magnetic layer 4
Since the Curie temperature of a is as high as 450 ° C., there is almost no decrease in coercive force, and since the coercive force is 1.5 kOe, the same information as that of the first magnetic layer 3 is recorded in the second magnetic layer 4 a. The magnetization state shown in FIG. 3 is obtained. The recording current Ia is
It is set so that sufficient recording can be performed on the first magnetic layer 3a. Therefore, when the coercive force of the second magnetic layer 4a is low, recording demagnetization may occur due to the recording current Ia, but the effect of the present invention does not pose any problem. As the temperature raising means for the magnetic head 7, a ceramic heater or the like may be used instead of the PTC thermistor. On the other hand, in order to read the information on the magnetic card 1a, it is not necessary to heat the magnetic card or erase the second magnetic layer 4a, so that the conventional read-only machine can be used.

When the first magnetic layer 3a is cooled to room temperature after recording information, the coercive force of the first magnetic layer 3a is restored to a high coercive force of 9 kOe. For this reason, even if it approaches a Nd-Fe-B type high magnetic force magnet as well as a handbag, a stop magnet of an eyeglass case, a magnetnet clip, etc.
Of the first magnetic layer 3 although the magnetization of the magnetic layer 4a of
The magnetization of a is hardly affected. At this time, as can be seen from the reproduction output ratio of FIG. 2, the reproduction output obtained from the magnetic card 1a is 80% before the information is erased from the second magnetic layer 4a. I do not receive it.

FIG. 4 shows a magnetized state when the legitimate information of the magnetic card 1a according to the present invention is falsified. In order to rewrite the information on the magnetic card 1a, the first magnetic layer 3
It is necessary to apply a magnetic field greater than the coercive force of a. But,
The magnetic head used in the conventional recording / reproducing apparatus has 6
A recording magnetic field of about kOe is limited, and a recording magnetic field of 9 kOe or more that can sufficiently magnetize the first magnetic layer 3a cannot be generated. Therefore, the second magnetic layer 4a having a low coercive force
Even if the information is rewritten, the normal information remains in the first magnetic layer 3a, and the magnetization state becomes as shown in FIG. The information obtained by reproducing the magnetic card 1a is processed as a falsified magnetic card in which the legitimate information of the first magnetic layer 3a and the falsified information of the second magnetic layer 4a are mixed. .

When there is a discrepancy in the personal identification numbers and there is a suspicion of illegal use, the conventional recording / reproducing apparatus deals with this by erasing or rewriting the information on the magnetic card. According to the magnetic card and the recording / reproducing apparatus of the present invention, when there is a suspicion of improper use due to mismatch of the secret codes, the recorded information of the first magnetic layer 3a having a high coercive force is not affected, and the second magnetic layer is used. By the recording magnetic field of the magnetic head 7 by the recording current Ib capable of magnetizing the layer 4a, recording is performed only on the second magnetic layer 4a having a low coercive force without heating the magnetic card. The magnetized state at this time is as shown in FIG. 4 just as in the case where the information of the magnetic card 1a according to the present invention which has been properly recorded is tampered with by the conventional recording / reproducing apparatus. With this magnetic card 1a, it becomes impossible to read accurate information, and it is possible to take measures such as invalidating the subsequent use of the magnetic card 1a. Obviously, it is possible to perform recording only on the second magnetic layer 4a and prevent unauthorized use, even with a conventional recording / reproducing apparatus.

Further, in the magnetic card 1a in which the second magnetic layer 4a has been rewritten in this way, the original signal is left in the first magnetic layer 3a, so the second magnetic layer 4a should be erased. Since the original information can be read again with, the magnetic card can be reused without reissuing.

Further, for an illegal card in which the information of the magnetic card 1a according to the present invention is directly copied onto a conventional magnetic card having a coercive force of 200 Oe or more and 6 kOe or less,
The information of the magnetic card 1a cannot be read by the recording / reproducing apparatus according to the present invention, which can apply a magnetic field in a range in which the recorded information of the magnetic layer 4a is not lost by a high magnetic force magnet, a DC electromagnet, a magnetic head or the like. However, the information on the fraudulent card is erased and the information cannot be read, thus preventing illegal use.

The coercive force of the first magnetic layer 3a at room temperature may be such that it cannot be sufficiently magnetized by a magnetic head made of an existing Fe-Ni-based alloy or Fe-Co-based amorphous alloy, and is 7 kOe or more. A magnetic layer having a coercive force is preferable. The material of the first magnetic layer 3a is Sm-C shown in FIG. 2 and Table 5.
O-based magnetic powder, Sr ferrite-based magnetic powder, Nd-Fe
It may be a B-type magnetic powder. Moreover, the upper limit of the coercive force of the magnetic powder realized at a Curie temperature of 100 ° C. or higher and 200 ° C. or lower is 15 kOe for Nd—Fe—B magnetic powder.
Is. Therefore, the coercive force of the first magnetic layer 3a at room temperature is 7 kOe or more and 15 kOe or less. In contrast, the second
The coercive force of the magnetic layer 4a at room temperature has a lower limit of 200 Oe at which recording can be held as a magnetic card, and coercive force capable of recording information with a conventional magnetic head made of an Fe-Ni-based alloy or an Fe-Co-based amorphous alloy. Is 6 kOe, the second magnetic layer has a coercive force of 200 at room temperature.
The range of Oe or more and 6 kOe or less is desirable.

FIG. 5 shows, as another embodiment of the magnetic card according to the present invention, the material of the magnetic powder of the first magnetic layer 3b having a high coercive force and the second magnetic layer 4b having a low coercive force, the Curie temperature, The coercive force and the reproduction output ratio (relative value) are shown.

FIG. 6 is a conceptual diagram of the basic structure of the magnetic card 1b having the characteristics shown in FIG. 5 and the magnetic card recording / reproducing apparatus according to the present invention. Similar to the embodiment of the magnetic card 1a having the characteristics shown in FIG. 2 and the magnetic card recording / reproducing apparatus according to the present invention, the magnetic card 1b is heated and the first magnetic layer 3 is heated.
The coercive force of b is kept in the range of 200 Oe to 4 kOe where the magnetic head 7b can record and the recorded information can be held.
In this state, information is recorded on the first magnetic layer 3b by the magnetic head 7b which is supplied with the recording current Ic. At this time, when the temperature of the second magnetic layer 4b is equal to or higher than the Curie temperature of the second magnetic layer 4b, the coercive force is almost zero, so the magnetization state of the second magnetic layer 4b is as shown in FIG. No information is recorded. When the temperature of the second magnetic layer 4b dropped and the coercive force began to return to about several tens of Oe, the first information was recorded.
Of the second magnetic layer 4b by the magnetic field generated by the magnetic layer 3b of
Is magnetized, and the information recorded in the first magnetic layer 3b is transferred by the time the temperature returns to room temperature.

FIG. 7 shows a magnetization state in which the information of the first magnetic layer 3b is transferred to the second magnetic layer 4b. Magnetic card 1
Since the reproduction output of b is transferred, the first magnetic layer 3
b and the reproduction output of the second magnetic layer 4b. When the reproduction output of the first magnetic layer 3b is 1, the second magnetic layer 4b
The reproduction output is 1/5, and the output obtained by reproducing the magnetic card 1b is 4/5, so that there is no problem in reading the information. Further, it is obvious that the same effect as that of the magnetic card 1a having the characteristics of FIG. 2 can be obtained in dealing with the case where the information on the illegal card or the second magnetic layer 4b is erased.

Consider the reproduction output ratio of the first magnetic layer and the second magnetic layer of the magnetic card. When the reproduction output of the first magnetic layer 3a of the magnetic card 1a is 1, and the reproduction output ratio of the second magnetic layer 4a to the first magnetic layer 3a is less than 1/10,
The second magnetic layer 4 is provided so that the use of the magnetic card 1a is invalidated.
Even if recording is performed on a, the first magnetic layer 3 is read at the time of reading information.
The reproduction output of a becomes dominant, and only the information of the first magnetic layer 3a is obtained, and the use of the magnetic card 1a cannot be invalidated. Further, when the reproduction output ratio of the second magnetic layer 4a exceeds 1/2, the first magnetic layer 3a and the second magnetic layer 4 are formed.
When the same information is recorded in a, the reproduction output of the magnetic card 1a exceeds 1.5 and it is determined that the card is an illegal card. This is because the playback device for magnetic cards generally has a higher playback output than a regular magnetic card, so the level at which it is judged as an illegal card is
This is because the reproduction output of the regular card is 1.5 and is 1.5 or more.

Next, the first magnetic layer 3b of the magnetic card 1b.
If the reproduction output ratio of the second magnetic layer 4b to the first magnetic layer 3b is set to less than 1/10 with the reproduction output of 1 as 1, the use of the magnetic card 1b is disabled in the second magnetic layer 4b. Even if recording is performed, the information in the first magnetic layer 3b becomes dominant at the time of reading as in the magnetic card 1a.
The use of b cannot be disabled. On the other hand, magnetic card 1b
When the same information is recorded on the first magnetic layer 3b and the second magnetic layer 4b, transfer occurs. Therefore, the magnetic card 1b
The reproduction output of is obtained as the difference between the outputs of both magnetic layers. Generally, since the recording / reproducing apparatus for a magnetic card is smaller than the reproduction output of a regular magnetic card, the level at which it is determined as an illegal card is 0.5 with the reproduction output of a regular card as 1.
Therefore, in the magnetic card having the Curie temperature and coercive force characteristics shown in Table 2, the upper limit of the reproduction output of the second magnetic layer 4b is preferably 1/2 or less of the first magnetic layer 3b.

From the above, the reproduction output ratio of the first magnetic layer and the second magnetic layer of the magnetic card is 1 when the reproduction output of the first magnetic layer is 1. It is preferably / 10 or more and 1/2 or less.

On the other hand, the card substrate is required to have workability. Generally, vinyl chloride is used as the substrate in consideration of embossability. However, since the magnetic card of the present invention heats the first magnetic layer having a high coercive force in the range of 100 ° C. to 200 ° C. around the Curie temperature, vinyl chloride having a softening temperature of about 70 ° C. is used as the base material. When it is used for the above, thermal deformation occurs, and problems such as deterioration of head touch occur during subsequent recording / reproducing. Therefore, it is desired that the base material has a high softening temperature and good embossing workability. However, it is difficult to select a plastic material that satisfies such conditions, and a magnetic card structure as shown in the examples of FIGS. 8 to 10 can be considered.

8 to 10 are sectional views of the magnetic card in the direction perpendicular to the magnetic stripe. FIG. 8 shows an example of a magnetic card in which four blocks are bonded. The magnetic layer 8 includes the first magnetic layer, the second magnetic layer, and the protective layer, is laminated on the high heat resistant substrate 9, and is treated as a one-block structure. Since the high heat resistant substrate 9 is directly below the magnetic layer 8 and is required to have the highest heat resistance, it is preferable to use polyimide or polyether imide. High heat-resistant substrate 9 on which magnetic layer 8 is laminated
Is laminated on the heat resistant substrate 10. The heat-resistant base material 10 is not required to have high heat resistance because the high-heat-resistant base material 9 is interposed between the heat-resistant base material 10 and the magnetic layer 8. Therefore, thermoplastic polycarbonate or the like, which has a softening temperature lower than that of the high heat-resistant substrate 9, is suitable. On the other hand, the heat resistance and workability of the base material 11 are similar to those of the conventional one, and vinyl chloride or the like is preferable. FIG. 9 shows an example of a five-block structure in which a part of the heat resistant base material 10 is changed to a base material 11 in order to improve the workability of the embossed area. FIG. 10 shows an example of a 7-block structure in which magnetic stripes are provided on both sides.

[0031]

As described above, according to the present invention, the following effects can be obtained.

(1) The coercive force of the magnetic card is higher in the first magnetic layer than in the second magnetic layer. Moreover, since the first magnetic layer preferably has 7 kOe to 15 kOe at room temperature,
It is possible to prevent tampering with a conventional recording / reproducing apparatus. Further, even if the information recorded in the first magnetic layer having a high coercive force is accidentally brought close to the high magnetic force magnet, the reading of the information is not affected at all.

(2) The magnetic card constructed as described above is heated to a temperature near the Curie temperature to give a coercive force of 200 O.
By setting e to 4 kOe, it becomes possible to record information on the first magnetic layer using a conventional magnetic head. A halogen lamp used as a magnetic card heating means can be heated immediately after light emission, has a fast rise time, and does not need to be kept at a high temperature during standby. Moreover, the surface of the magnetic card is not scratched as compared with the contact heating method. When the temperature of the magnetic head is raised from 50 ° C. to 70 ° C. by the temperature raising means, the first
Since the temperature variation of the magnetic layer can be suppressed, stable recording characteristics can be obtained, and the temperature decrease can be mitigated, the heating temperature of the first magnetic layer by the halogen lamp can be set low, and the thermal damage to the magnetic card can be reduced. .

(3) As is important with this type of magnetic card, recording can be performed on the second magnetic layer as necessary, and it is possible to make the use of the magnetic card invalid. Further, it is possible to reuse the magnetic card without reissuing it by only erasing the second magnetic layer.

(4) The coercive force of the magnetic layer is from 200 Oe to 6
Even if the information of the magnetic card according to the present invention is copied as it is onto a conventional magnetic card of 000 Oe to forge,
The magnetic card recording / reproducing apparatus according to the present invention having a DC electromagnet, a high magnetic force magnet, a magnetic head, etc., can erase the information on the conventional magnetic card which is determined to have a high suspicion of tampering. Can be prevented.

(5) If a material having a high Curie point is used for the second magnetic layer, simultaneous recording of the first magnetic layer and the second magnetic layer allows the first magnetic layer and the second magnetic layer to be recorded. Since a high output combined with the output can be obtained, it is possible to obtain a sufficient output even if the first magnetic layer is made of a material having a low residual magnetic flux density, and an inexpensive material can be selected.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a magnetic card according to the present invention.

FIG. 2 is a diagram showing a material of the magnetic powders of the first magnetic layer and the second magnetic layer, Curie temperature,
An example of coercive force and reproduction output ratio (relative value) is shown.

FIG. 3 is a conceptual diagram showing a basic configuration of the magnetic card (the protective layer is omitted) and its recording / reproducing apparatus shown in FIG.

FIG. 4 is a diagram showing a magnetized state when the legitimate information of the magnetic card shown in FIG. 1 is falsified.

FIG. 5 is a first embodiment of another embodiment of the magnetic card according to the present invention.
The magnetic powder material, Curie temperature, coercive force, and reproduction output ratio (relative value) of the magnetic layer and the second magnetic layer are shown.

6 is a conceptual diagram showing the basic configuration of the magnetic card (the protective layer is omitted) and its recording / reproducing apparatus shown in FIG.

7 is a diagram showing a magnetized state after the information of the first magnetic layer is transferred to the second magnetic layer of the magnetic card shown in FIG.

FIG. 8 is a cross-sectional view of the magnetic card in the direction perpendicular to the magnetic stripe, showing an example of the magnetic card with four blocks bonded together.

FIG. 9 is a cross-sectional view of the magnetic card in the direction perpendicular to the magnetic stripe, showing an example of a five-block structure in which a part of the heat-resistant base material is changed to a base material in order to improve the processability of the embossed region.

FIG. 10 is a cross-sectional view of the magnetic card in the direction perpendicular to the magnetic stripes, showing an example of a 7-block structure in which magnetic stripes are provided on both sides.

[Explanation of symbols]

 1a, 1b Magnetic card 2a, 2b Plastic substrate 3a, 3b First magnetic layer 4a, 4b Second magnetic layer 5 Protective layer 6a, 6b Halogen lamp 7a, 7b Magnetic head 8 Magnetic layer 9 High heat-resistant substrate 10 Heat-resistant substrate Material 11 Base material

Claims (5)

[Claims] 1. In a magnetic card in which two magnetic layers having different coercive forces in a predetermined state are laminated on a substrate, the Curie temperature of the first magnetic layer having a high coercive force is 100 ° C. or higher.
The reproduction output of the second magnetic layer having a low coercive force in the range of 00 ° C. or lower is 1/10 of the reproduction output of the first magnetic layer.
A magnetic card characterized by being in the range of ½ or less. 2. The recording / reproducing apparatus for a magnetic card according to claim 1, further comprising means for heating the first magnetic layer to record information at least. 3. The recording on the magnetic card according to claim 1, wherein information is recorded only on the second magnetic layer by a recording magnetic field of a magnetic head that does not affect recorded information on the first magnetic layer. A recording / reproducing apparatus for a magnetic card, characterized by comprising means. 4. A recording / reproducing apparatus for a magnetic card according to claim 2, further comprising a lamp as a heating means. 5. The recording / reproducing apparatus for a magnetic card according to claim 2, further comprising magnetic field generating means within a range in which recorded information on the first magnetic layer is not demagnetized.