JPH1040535A - Magnetic card - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a magnetic card which facilitates recording on magnetic recording and improves reproduction output. SOLUTION: A magnetic card having a soft magnetic layer 2 as a first magnetic layer on a substrate 1, and a magnetic recording layer 3 provided thereon.

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 magnetizability and being excellent in preventing forgery.

[0002]

2. Description of the Related Art A magnetic card used as a cash voucher such as a ticket, a telephone card, a prepaid card, etc. is provided by a predetermined device each time the magnetic card is used. It is used by rewriting predetermined information.

In order to prevent forgery, these magnetic cards are provided with a protective layer on the magnetic recording layer or a multilayered magnetic recording layer.

[0004] However, with the spread of magnetic cards, device technology for reproducing and recording information on magnetic cards has also been developed, and information recorded on magnetic cards can be easily read, and even information can be written.

As a countermeasure against this, various measures have been taken, such as providing a protective layer on the magnetic recording layer or increasing the number of magnetic recording layers.

[0006]

However, due to such measures, the lines of magnetic force from the magnetic recording head do not sufficiently reach the magnetic recording layer farthest from the head, resulting in insufficient recording, and insufficient reproduction of information. Output cannot be obtained.

Further, when a high coercivity material is used for the magnetic recording layer to enhance security, information is difficult to be recorded, so that the output at the time of reading is also weak, and S
Since the / N ratio also becomes small, it causes output of incorrect information.

In view of the above, it is an object of the present invention to provide a magnetic card which facilitates recording on a magnetic recording layer and improves output during reproduction.

[0009]

As a result of various studies to solve the above-mentioned problems, the present inventor has found that a soft magnetic layer is provided between a substrate and a magnetic recording layer to record / record information.
It has been found that a magnetic card which is excellent in reproduction and in which the use of a high coercive force material for the magnetic recording layer makes it difficult to erase and write information for the purpose of forgery can be provided.

That is, according to the present invention, a soft magnetic layer is provided as a first magnetic layer on a substrate, and at least one magnetic recording layer is provided as another magnetic layer on the soft magnetic layer. Is obtained.

Further, according to the present invention, in the above magnetic card, a magnetic card characterized in that the magnetic material contained in the first magnetic layer has a coercive force of 50 Oe or less.

The operation of the present invention will be described. The magnetic recording layer is multi-layered to prevent forgery, or the card is multi-layered by providing a protective layer. The magnetic field lines generated from the magnetic recording head are not sufficiently magnetized in the magnetic recording layer farthest from the magnetic recording head, information is insufficiently recorded, the output at the time of reading becomes weak, and S
Since the / N ratio also becomes small, it causes output of incorrect information. Also, when a high coercive force material is provided in the magnetic recording layer, information is still difficult to be recorded, which causes erroneous information to be output as described above.

In order to solve this problem, the present invention provides a soft magnetic layer between the substrate and the magnetic recording layer, which increases the average magnetic permeability of the entire magnetic layer. Even if the layer is a multilayer, or even if a high coercive force material is used for the magnetic recording layer, the magnetic field lines from the magnetic recording head can sufficiently and easily reach the magnetic recording layer farthest from the head, and sufficient recording can be performed. . Therefore, a sufficient output can be obtained in reproducing the information, and erroneous information is not provided due to insufficient output. Note that the coercive force of soft magnetism is 50
The reason for setting Oe or less is that when a magnetic material having a coercive force higher than that is used for the soft magnetic layer, the reproduction output is not sufficiently improved and the effect is lost.

When the magnetic recording layer of the other magnetic layer provided on the soft magnetic layer of the first magnetic layer has a multi-layer structure, the material used for the magnetic recording layer on the soft magnetic layer side has a high coercive force and a high magnetic coercive force. It is desirable to use a material having good magnetism. Thus, it is possible to supply a magnetic card having a forgery prevention effect in which it is difficult to erase and rewrite information once recorded.

[0015]

Embodiments of the present invention will be described below.

FIG. 1 is a partial sectional view of a magnetic card according to an embodiment of the present invention. The magnetic card shown in FIG.
A soft magnetic layer 2 as a first magnetic layer and a magnetic recording layer 3 and a protective layer 4 as other magnetic layers are sequentially provided thereon.

The soft magnetic layer 2 as the first magnetic layer can be formed as a coating type magnetic layer. in this case,
The soft magnetic layer 2 may be such that the magnetic material is dispersed in the binder at a weight ratio of about binder: magnetic material = 9: 1 to 1: 9 and contained in the soft magnetic layer 2. Note that two or more kinds of binders may be used, and a known dispersant, surface treatment agent, or the like may be contained.

The thickness of the soft magnetic layer 2 as the first magnetic layer is as follows:
The magnetic material contained in the soft magnetic layer 2 may be Ni-Zn ferrite, Mn-
Examples include, but are not limited to, Zn ferrite, permalloy and sendust. The larger the magnetic permeability of the soft magnetic material used in the soft magnetic layer 2 as the first magnetic layer, the better the permeability of the magnetic field lines from the head.

A magnetic recording layer 3 is provided between the soft magnetic layer 2 as the first magnetic layer and the protective layer 4 as another magnetic layer. Examples of the magnetic material contained in the magnetic recording layer 3 include magnetic powder such as barium ferrite, Sr ferrite, and Sm-Co alloy (Japanese Patent Application No. 6-320091). The magnetic recording layer 3 can be formed as a coating type magnetic layer, similarly to the soft magnetic layer 2 of the first magnetic layer, and the manufacturing condition is the same as that of the soft magnetic layer 2 of the first magnetic layer. Are the same as the conditions in the description. The magnetic recording layer 3 of another magnetic layer
May be used as a countermeasure for preventing forgery using a magnetic recording layer having a multilayer structure of two or more layers having different coercive forces.

The protective layer 4 provided on the magnetic recording layer 3 of another magnetic layer can be selected from known protective layers used for magnetic cards including a shield layer.

As described in detail above, according to the present invention, it is possible to provide a magnetic card having excellent magnetizability and having a forgery prevention effect.

(Examples) The present invention will be described in detail below with reference to examples.

First, a coating material A having the following composition was prepared using Ni-Zn ferrite powder. Ni-Zn ferrite 40 parts by weight Dispersant 3 parts by weight Polyurethane resin 13 parts by weight Polyisocyanate resin 2 parts by weight MEK 40 parts by weight MIBK 40 parts by weight Toluene 40 parts by weight The coercive force of Ni-Zn ferrite was 10 Oe.

Next, Sm, Co, A having a purity of 99.0% or more.
was melted to prepare an alloy having a composition of Sm19.1Co68.7Al12.2, hydrogen was absorbed at room temperature, and pulverized using the obtained powder jet mill to obtain a powder having an average particle diameter of 2 μm. Further, the obtained powder was subjected to a heat treatment at 1000 ° C. for 15 minutes in an Ar atmosphere to obtain a magnetic material No. 1. The coercive force of this magnetic material was 15 kOe.

Using the powder of the magnetic material No. 1, a paint B having the following composition was prepared. Magnetic material No. 1 50 parts by weight Dispersant 3 parts by weight Polyurethane resin 20 parts by weight Polyisocyanate resin 2 parts by weight MEK 40 parts by weight Cyclohexanone 40 parts by weight Toluene 40 parts by weight

Next, the coating material A was applied on a PET substrate and dried to form a first magnetic layer. Layer thickness after drying is about 5μm
Met. Further, the coating material B was applied on the first magnetic layer and dried to form another magnetic layer. The thickness of the other magnetic layers is about 10 μm
Met.

In this way, the substrate on which the first magnetic layer and the other magnetic layers were laminated was punched out to obtain a magnetic card. Recording was performed on the obtained magnetic card at a magnetic recording head recording density of 210 BPI, and reproduction was performed with an in-plane magnetic recording / reproduction head. As a result, an output of 3.1 V was obtained.

A magnetic card was manufactured in the same manner as described above, using magnetic materials having various coercive forces for the soft magnetic layer. Magnetic recording and reproduction were performed under the same conditions. FIG. 2 shows the relationship between the coercive force and the reproduction output at that time. This results in a coercivity of
It can be seen that the reproduction output decreases when it exceeds 0 Oe.

(Comparative Example) As a comparative example, a magnetic card having no soft magnetic layer was manufactured under the same manufacturing conditions by using the coating material B using the same magnetic material as that of the example. Then, a recording density of 210 B was applied to the obtained magnetic card with a magnetic recording head.
When recording was performed by PI and the information was reproduced by the in-plane magnetic recording / reproduction head, a reproduction output of 2.0 V was obtained.

[0030]

As described above, according to the present invention, it is possible to obtain a magnetic card having excellent magnetizability and an effect of preventing forgery, and to provide a magnetic card which is extremely useful in industry.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a relationship between a coercive force of a soft magnetic layer and a reproduction output of the magnetic card of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 soft magnetic layer (first magnetic layer) 3 magnetic recording layer (other magnetic layer) 4 protective layer

Claims (2)

[Claims] 1. A magnetic card having a soft magnetic layer as a first magnetic layer on a substrate and at least one or more magnetic recording layers as another magnetic layer on the soft magnetic layer. 2. The magnetic card according to claim 1, wherein the magnetic material contained in the first magnetic layer has a coercive force of 50%.
A magnetic card characterized by being equal to or less than Oe.