JPH1031816A - Magnetic card and magnetic recording method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a magnetic card which cannot erase or write information for the purpose of forgery and has higher security. SOLUTION: The magnetic card 10 having a magnetic layer 2 to a portion at least on the substrate 1, a magnetic material contained in the magnetic layer 2 has the general formula is represented by R _x T _100-xy M _y It has a composition that is Here, R is at least one element selected from rare earth elements containing Sm as an essential component and Y, and T is C
M is at least one selected from transition metals (Fe, Co, Ni) containing o as a main component, and M is Si, Ti, A
1, Ga, V, Cr, Mn, Cu, Zr, Nb, Mo,
It is represented by at least one of Pd, Hf, Ta, W, Pt, and Au, and the composition value x of R is 16.0 to 22.0,
The composition value y of M has a composition range of 0 ≦ y <30 (all at%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic card, and more particularly to a magnetic card having excellent security in which predetermined magnetically recorded information is difficult to be rewritten due to overwriting or the like, and a magnetic recording method thereof.

[0002]

2. Description of the Related Art Magnetic cards used as tickets, telephone cards, prepaid cards, etc., are:
Each time a card is used, it is used by rewriting predetermined information such as a balance on a magnetic recording layer provided on the card by a predetermined device. These cards are provided with measures such as providing a protective layer on the magnetic recording layer, making the magnetic recording layer multiple layers, or punching a hole in the card each time the card is used as a measure to prevent forgery. .

[0003]

However, with the spread of the magnetic card, the technology of a device for reproducing and recording information on the magnetic card has also been developed, and the information recorded on the magnetic card can be easily read and further written. Until now.

Specifically, each time a magnetic recording card is used,
All information, including new information, is rewritten so that it overwrites the old information, so if there is a device that records and reproduces information on the card, the information can be easily rewritten, thereby forging the card. Can be easily performed, and in recent years, forgery of magnetic cards has been remarkably increased.

It is considered that this is because the coercive force of the magnetic layer for performing magnetic recording is as low as 2 to 3 kOe.
In other words, if the coercive force of the magnetic layer is low, information can be easily rewritten by a conventional magnetic recording / reproducing apparatus, and the card can be forged.

Accordingly, a first technical object of the present invention is to provide a magnetic card which cannot erase or write information for the purpose of forgery, and a magnetic recording method therefor.

[0007] A second technical object of the present invention is to provide a magnetic card having better security.

[0008]

Means for Solving the Problems The present inventors first record in the longitudinal direction at the time of initial information recording, and then, when recording new information sequentially, partially delete the existing information. We studied a method to record new information by destroying it. As a result, the present inventors have found a magnetic card and a magnetic recording method having excellent security, and have accomplished the present invention.

The magnetic card of the present invention has a magnetic layer having a high coercive force as compared with the conventional magnetic card, and the magnetic layer has characteristics excellent in magnetization. Further, in the present invention, a magnetic recording method in which a magnetic field is applied to the magnetic layer in advance when reading recorded information on the magnetic layer, and thereafter the recorded information is read.

Here, the magnetic layer having a high coercive force of the magnetic card according to the present invention has a coercive force of 3.0 kOe or more and has a coercive force of at least 3.0 kOe because erasing or overwriting of recorded information is difficult (impossible). 1/1 of coercive force for effective expression
It is preferable to have a magnetization of 25% or more of the saturation magnetization with an applied magnetic field of 2 or less.

[0011] as a good magnetic layer and adhesion-magnetic high coercivity in the present invention have the general _{formula, R x T 100-xy M} y ( wherein, R is selected from rare earth elements including Y as an essential component Sm T is at least one selected from transition metals (Fe, Co, Ni) containing Co as a main component, and M is Si, Ti, Al, Ga, V,
Cr, Mn, Cu, Zr, Nb, Mo, Pd, Hf, T
a, W, Pt, and Au are represented by at least one kind, and the composition value x of R is 16.0 to 22.0, and the composition value y of M
Has a composition range of 0 ≦ y <30 (all at%). In the method for manufacturing a magnetic layer according to the present invention, it is preferable that a magnetic material is dispersed in a binder to form a magnetic layer.

[0012] In the present invention, reasons for limiting the composition of the general formula, in _{R x T 100-xy M y} , x is 1
If it is less than 6.0 at%, the coercive force is reduced to 22.0 at%.
This is because the magnetization is undesirably reduced above.
This is because if M is at least 30 at%, the coercive force decreases, which is not preferable.

In the magnetic recording method of the present invention,
In the method of magnetic recording on the magnetic layer of any of the magnetic cards described above, first, initial information is recorded, and then, when new information is sequentially recorded each time the card is used, a part of the existing information is recorded. The new information is recorded by destroying the information.

Further, in the magnetic recording method of the present invention,
When reading recorded information on the magnetic layer, it is preferable to apply a magnetic field to the magnetic layer in advance, and then read the recorded information.

Specifically, according to the present invention, first, when initial information is recorded, recording is performed in the longitudinal direction, and when new information is sequentially recorded, a part of existing information is destroyed. (Overwriting, etc.) to record new information.

Furthermore, in the present invention, forgery is aimed at by using a magnetic recording material in which the initial magnetic recording is easy, the coercive force is high, and the information once recorded is difficult or impossible to rewrite. It is possible to provide a high-security magnetic recording system in which information cannot be erased or written and a magnetic card having a magnetic layer.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partial sectional view showing a magnetic card according to an embodiment of the present invention. As shown in FIG. 1, a magnetic card 10 has a magnetic layer 2, a non-magnetic layer 3, and a protective layer 4 thereon in this order on a substrate 1. The magnetic layer 2 magnetic material contained in the general formula, having a composition represented by _{R x T 100-xy M y} .

In the above general formula, R is at least one element selected from rare earth elements containing Sm as an essential component and Y, and T is a transition metal (Fe,
At least one selected from Co, Ni), M
Are Si, Ti, Al, Ga, V, Cr, Mn, Cu,
It is represented by at least one of Zr, Nb, Mo, Pd, Hf, Ta, W, Pt, and Au, and the composition value x of R is 1
6.0 to 22.0 at%, and the composition value y of M is 0 ≦ y <30.
The composition range is at%.

Here, the reasons for limiting the composition are as follows:
In _{R x T 100-xy M y} , x decreases the coercive force is less 16.0At%, at 22.0At% or more is because the magnetization is not preferable to decrease, also, M is the is more than 30 at% This is because a decrease in coercive force is observed, which is not preferable.

The magnetic material having the above composition may be produced by a rapid quenching method or a diffusion reduction method, or may be a bulk alloy obtained by ordinary melting and cooling, an alloy obtained by powder metallurgy, The powder can be obtained by a ball mill, vibration mill, jet mill, hydrogen storage pulverization, or the like.

The powder obtained by the above method may be heat-treated in a vacuum or in an inert atmosphere at a temperature in the range of 600 to 1100 ° C. to obtain a desired particle size.

The coercive force of such a magnetic material is 3 k
Oe or more, which is sufficient for obtaining the effects of the present invention.

The magnetic layer 2 can be formed as a coating type magnetic layer. In this case, the magnetic layer 2 may be formed by dispersing the above magnetic material in a binder, and may be contained in the magnetic layer at a weight ratio of binder: magnetic material = 9: 1 to 1: 9.

Incidentally, two or more binders may be used.
Further, a known dispersant, surface treatment agent and the like may be contained. Further, the thickness of the magnetic layer 2 may be about 0.5 to 50 μm. The nonmagnetic layer 3 is provided in an area different from the magnetic layer 2. The material of the non-magnetic layer 3 is not particularly limited, and may have a structure in which the entire surface of the card is the magnetic layer 2 and the non-magnetic layer is not formed. The protective layer 4 provided on the magnetic layer 2 and the nonmagnetic layer 3 can be selected from, for example, a protective layer made of a known resin used for a magnetic card including a shield.

The magnetic card 10 manufactured as described above
Has a high coercivity magnetic layer 2 having a magnetization of 25% or more of the saturation magnetization with an applied magnetic field having a coercivity of 3.0 kOe or more and a half or less of the coercivity. . This magnetic layer can easily record information, but it is difficult or impossible to erase or rewrite the recorded information.

Further, in the method of performing magnetic recording in the longitudinal direction in the plane of the magnetic card, the magnetic layer records information in the longitudinal direction at the time of initial information recording, and then records new information sequentially thereafter. In this case, new information can be recorded by destroying a part of the existing information. Here, when recording information, in-plane magnetic recording is performed on the magnetic layer,
When reproducing, it can be read using an in-plane magnetic recording / reproducing device. Even when a fixed one-directional magnetic field is applied in the in-plane direction using a magnetic head, the magnetic information of the magnetic layer remains without being erased because of the high coercive force.

When new information is recorded on the magnetic layer, new information can be recorded by destroying a part of the existing recorded information.

Therefore, it is possible to provide a magnetic card which can be additionally written and which is difficult or impossible to rewrite.

Hereinafter, the specific manufacture of the magnetic card according to the embodiment of the present invention will be described. First, purity 99.
Dissolve 0% or more of Sm and Co to make Sm _19.1 Co _68.7 Al
An alloy having a composition of _12.2 was prepared, hydrogen was absorbed at room temperature, and the obtained powder was pulverized using a jet mill to obtain a powder having an average particle diameter of 2 μm. Further, 100
Heat treatment in an Ar atmosphere at 0 ° C. for 15 minutes to obtain a magnetic material N
o. 1 was obtained.

The coercive force of this magnetic material was 15 kOe. This magnetic material No. Using the powder of No. 1, paint A having the composition shown in Table 1 below was prepared.

[0032]

[Table 1] Next, paint B having the composition shown in Table 2 below was prepared.

[0033]

[Table 2]

Next, paint A and paint B were simultaneously applied in parallel on a PET substrate and dried to form a magnetic layer. The layer thickness after drying was about 10 μm each. The substrate coated with the magnetic layer and the non-magnetic layer was punched to obtain a magnetic card 10.
Recording was performed on the magnetic layer 2 (see FIG. 1) of the obtained magnetic card 10 at a recording density of 210 BPI with a magnetic recording head and reproduction was performed with an in-plane magnetic recording / reproduction head. As a result, an output of 3.0 V was obtained.

Next, on the magnetic layer 2 of the recorded magnetic card,
When a unidirectional magnetic field was applied by the in-plane magnetic recording / reproducing head to erase and reproduce the information, the initially recorded information could be read with an output of about 2V. In addition, when the recorded magnetic card was overwritten by a magnetic recording head and reproduced, it was confirmed that neither the initially recorded information nor the overwritten information could be accurately read, and that the information was destroyed. .

In the embodiment described above, the magnetic layer 2
And the non-magnetic layer 3 were simultaneously coated and formed, but the method of manufacturing the magnetic card of the present invention is not limited thereto.
As a method of separately applying the magnetic layer and the non-magnetic layer and a coating method, a method such as gravure, reverse roll, and die coater can be applied.

[0037]

As described above, according to the present invention,
Since it is difficult or impossible to erase or rewrite recorded information, it is possible to obtain a magnetic card that cannot erase or write information for the purpose of forgery, and is extremely useful in industrial and security applications. A magnetic recording method can be provided.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Magnetic layer 3 Non-magnetic layer 4 Protective layer 10 Magnetic card

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location // B22F 1/00 H01F 1/04 B

Claims (5)

[Claims] 1. A magnetic material having a magnetic layer entirely or partially on a substrate, wherein a magnetic material contained in the magnetic layer is represented by a general formula:
_x T _100-xy M _y (where, R represents at least one selected from rare earth elements including Y as an essential component Sm, T
Is a transition metal whose main component is Co (Fe, Co, Ni)
At least one selected from the group consisting of Si, T
i, Al, Ga, V, Cr, Mn, Cu, Zr, Nb,
It is represented by at least one of Mo, Pd, Hf, Ta, W, Pt, and Au, and the composition value X of R is 16.0-2.
The composition value y of 2.0 and M is 0 ≦ y <30 (all at at
%). A magnetic card having a composition represented by the formula (1), wherein the magnetic layer is formed by dispersing the magnetic material in a binder. 2. The magnetic card according to claim 1, wherein when magnetic recording is performed on the magnetic layer, firstly, initial information is recorded, and thereafter, when new information is sequentially recorded each time the magnetic layer is used, A magnetic card which records new information by destroying a part of existing information. 3. The magnetic card according to claim 1, wherein a magnetic field is applied to the magnetic layer before reading the recorded information on the magnetic layer, and then the recorded information is read. 4. The method for magnetically recording on the magnetic layer of the magnetic card according to claim 1, wherein firstly, initial information is recorded,
Further, a magnetic recording method characterized in that when new information is successively recorded each time it is used, new information is recorded by destroying a part of the existing information. 5. The magnetic recording method according to claim 4, wherein
A magnetic recording method comprising: applying a magnetic field to the magnetic layer in advance when reading recorded information on the magnetic layer; and then reading the recorded information.