JPH0877685A - Magnetic recording system and magnetic recording medium - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnetic recording system and a magnetic recording medium that can easily rewrite information without the need to prepare a special magnetic recording / reproducing device and have an excellent anti-counterfeiting effect. [Structure] A fixed information area 51 and an erased information area 52 are provided in the longitudinal direction of the information area 5 of the magnetic card 1. Fixed information is recorded in the fixed information area. Variable information is magnetically recorded in the erase information area as a group of a plurality of recordings. These recordings are performed using a magnetic head (for example, generated magnetic field: 10 kG). Rewriting of variable information is performed by magnetically erasing a selected record from a plurality of records instead of recording. The magnetic layer of the magnetic card has a coercive force of 4 kOe or less, and although the recorded information can be easily erased, it is difficult or impossible to write or rewrite the record.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording system and a magnetic recording medium.

[0002]

2. Description of the Related Art Conventionally, as one type of magnetic recording medium, a magnetic card used as a cash voucher such as a ticket, a telephone card, or a prepaid card is known.
This magnetic card is provided with a magnetic layer on a base for recording predetermined information such as remaining money. Then, each time the magnetic card is used in a predetermined device, the recording on the magnetic layer is rewritten.

The information recorded on the magnetic layer of this type of magnetic card is usually readable by a magnetic viewer or the like. This increases the risk of forgery or alteration of the magnetic card.

In order to prevent forgery and alteration of the magnetic card,
Various measures have been taken such as providing a protective layer on the magnetic layer, forming the magnetic layer in multiple layers, and punching a magnetic card with each use.

The base of the magnetic card is made of polyethylene terephthalate (PET) resin, for example. On the other hand, for the magnetic layer, a magnetic paint in which magnetic powder of barium ferrite having a coercive force of 2 to 3 kOe is dispersed in a resin binder such as vinyl chloride or vinyl acetate together with a dispersant such as stearic acid is applied to the surface of the substrate. It is formed by

[0006]

Recently, along with the widespread use of magnetic cards, magnetic recording / reproducing devices for recording and reproducing information on the magnetic cards have been developed, and the information recorded on the magnetic cards can be easily read, and further, You can write information. Therefore, the conventional magnetic card has a drawback that it cannot effectively prevent forgery and alteration. Specifically, all information including new information generated at each use of the magnetic card is rewritten each time in a form of overwriting the old information, so that it is a device that records and reproduces card information. It is possible to easily rewrite information and thereby forge a magnetic card.

The reason for permitting forgery and alteration of the magnetic card is that the coercive force of the magnetic layer is as low as 2 to 3 kOe so that it can be rewritten by the conventional magnetic recording / reproducing apparatus. That is, if the coercive force of the magnetic layer is low, the information can be easily rewritten by the conventional magnetic recording / retransmission device, and the card can be forged or altered.

The recording magnetic head used in the conventional magnetic recording / reproducing apparatus can generate a magnetic field of about 5 kG. The coercive force of the magnetic layer of a magnetic card that can be magnetized (recordable) by this magnetic head is about 2 to 3 kOe, which is about half the magnetic field generated by the head. If the coercive force is larger than this, rewriting (overwriting) becomes difficult. Due to such circumstances, card forgery has not been fundamentally prevented.

That is, the problem with the prior art is that each time a magnetic card is used, new information such as the remaining amount and the used amount is written by overwriting the existing recorded information. If the coercive force of the magnetic layer is too large,
The conventional magnetic recording / reproducing apparatus cannot rewrite information.

Therefore, an object of the present invention is to provide a magnetic recording system and a magnetic recording medium which can easily rewrite information without the need for preparing a special magnetic recording / reproducing apparatus and which has an excellent anti-counterfeiting effect. Especially.

Another problem of the present invention is that it is difficult to attach magnetism.
It is to provide a magnetic recording medium having a low coercive force and excellent erasability.

Still another object of the present invention is to provide a magnetic recording system which produces a great effect by using the magnetic recording medium.

[0013]

According to the magnetic recording method of the present invention, information is magnetically recorded on a magnetic recording medium as a group of a plurality of recordings, and the rewriting of the information is selected from the plurality of recordings. It is characterized in that the recorded data is only erased magnetically.

Further, in the magnetic recording system of the present invention, a fixed information area and an erased information area are provided on the magnetic recording medium, fixed information is recorded in the fixed information area, and a plurality of variable information is recorded in the erased information area. It is characterized in that magnetic recording is performed as a group of recordings, and rewriting of the variable information is performed only by magnetically erasing a recording selected from the plurality of recordings. In this case, reading the fixed information and the variable information, processing the variable information with reference to the fixed information, and magnetically erasing a selected record from the plurality of records from the erase information area. Therefore, it is preferable to rewrite the variable information.

According to the present invention, in a magnetic recording medium having a magnetic layer provided on a substrate, the magnetic layer has the general formula RaCo1.
00-b-c-dFebCuZrd (where R is Sm
Is a rare earth element containing at least one or more Y as a main component.

[Equation 2] A magnetic recording medium characterized by containing the magnetic powder represented by

[0016]

1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention. This magnetic recording medium is the magnetic card 1 used as a ticket such as a ticket, a telephone card, or a prepaid card. This magnetic card 1
Is a magnetic layer 3 formed on one main surface of a base 2 made of polyethylene terephthalate (PET) resin by applying a magnetic paint described later, and a protective layer 4 is further formed thereon as needed. is there.

FIG. 2 is a diagram for explaining a magnetic recording system according to an embodiment of the present invention. The magnetic layer of the magnetic card 1 is provided with a striped information area 5 extending between both ends in the longitudinal direction of the magnetic card 1. Information area 5
Although the above description is made so as to be clearly visible in the drawings for the sake of convenience, it is desirable that the element be provided in a form that cannot be actually viewed.

In the information area 5, information as initial information is magnetically recorded as a group of a plurality of recordings adjacent in the longitudinal direction. Specifically, the number of records corresponding to the amount of money of the magnetic card 1 is recorded in the information area 5 in a state of being adjacent in the longitudinal direction. Therefore, the portion of the information area 5 in which information is recorded has a length depending on the set amount of money of the magnetic card 1. The portions where information is recorded are shown by hatching.

Rewriting of information in the information area 5 is performed only by magnetically erasing a selected record of the plurality of records. Specifically, a plurality of records in the information area 5 are erased in order from the end in the longitudinal direction according to the frequency of use of the magnetic card 1. Therefore, the portion of the information area 5 where information is recorded (that is, the hatched portion) is shortened in sequence as indicated by the arrow 6 in FIG. 2 as the magnetic card 1 is used.

Information can be rewritten by erasing a plurality of recordings in the information area 5 in the middle portion in the longitudinal direction.

FIG. 3 is a diagram for explaining a magnetic recording system according to another embodiment of the present invention. The magnetic layer of the magnetic card 1 is provided with a striped information area 5 extending between both ends in the longitudinal direction of the magnetic card 1. Information area 5
A fixed information area 51 and an erased information area 52 are provided adjacent to each other in the longitudinal direction. Fixed information is recorded in the fixed information area 51. On the other hand, the erase information area 52
The variable information is magnetically recorded as a collection of a plurality of recordings. Rewriting of the variable information in the erase information area 52 is performed only by magnetically erasing a selected record of the plurality of records. In this case, the magnetic recording / reproducing apparatus reads the fixed information and the variable information, the processing circuit refers to the fixed information to perform a predetermined process on the variable information, and then the magnetic recording / reproducing apparatus writes a plurality of information from the erase information area 52. It is preferable to rewrite the variable information by magnetically erasing a selected one of the records.

Next, the magnetic paint for forming the magnetic layer of the magnetic card 1 will be described.

First, as a general description, R (where R is a rare earth element containing Sm as a main component and containing at least one or more types of Y), Co, Fe, Cu and Zr are melted and homogenized (1100 to 1210). ℃), then aging treatment (7
The magnetic alloy formed by
aCo100-b-c-dFebCuZrd

(Equation 3) The magnetic powder represented by This magnetic powder is kneaded with a binder to produce the above-mentioned magnetic paint.

Further, this magnetic coating material is applied to a substrate made of PET resin and dried, and a protective layer is provided if necessary to manufacture a magnetic card. The protective layer can be omitted, in which case the magnetic card can be manufactured more easily and thinly.

In the above general formula, a is 10.0a
If it is less than t%, the magnetizability is improved, and if a exceeds 13.5%, the coercive force becomes large and it becomes difficult to erase information. When b is less than 8.0 at%, the holding power becomes large and it becomes difficult to erase information, and when b exceeds 20.5 t%, the magnetizability is improved, which is not preferable. When c is less than 4.0 at%, the magnetizability is improved, and when c is more than 18.5 at%, the coercive force becomes large, both of which are not preferable. If d is less than 0.5 at% or exceeds 4.0 at%, the coercive force is reduced and the magnetizability is improved, which facilitates recording of information, which is not preferable.

Here, an example of a method for producing magnetic powder will be described. Sm, Co, Fe, Cu, Z with a purity of 99% or more
By melting r, Sm: 9.0 to 15.0 at
%, Fe: 7.2 to 21.9 at%, Cu: 3.1 to 1
9.6 at%, Zr: 0.2 to 4.5 at%, Co: b
An alloy having a composition of al was prepared, and this alloy was subjected to homogenizing heat treatment at a temperature of 1195 ° C. for 24 hours in an Ar atmosphere. Next, after aging treatment of the obtained alloy at a temperature of 700 to 900 ° C., each alloy was coarsely pulverized with a tisk mill and further finely pulverized with a ball mill to obtain a powder having an average particle diameter of 3 μm.

The magnetic properties of the obtained magnetic powder were measured using a vibrating sample magnetometer (VSM). The result is shown in Figure 4.
And shown in FIG. The magnetic characteristic B5 / B18 in the figure is the ratio of the magnetization in the applied magnetic field of 5 kOe to the magnetization in the applied magnetic field of 18 kOe in the initial magnetization curve. H _CJ (10) is a coercive force when the applied magnetic field is 10 kOe.

Using the above-mentioned magnetic powder, a magnetic coating material having the composition shown in Table 1 below is obtained.

[0029]

[Table 1]

Further, as shown in FIG. 1, the above-mentioned magnetic paint is applied onto a base 2 made of PET resin to have a thickness of 20 μm.
The coating was performed so that the magnetic card 1 having the magnetic layer 3 formed thereon was prepared.

A magnetic head (generated magnetic field of 10 kG) was used for the magnetic layer 3 of the magnetic card 1 thus obtained,
Recording was performed by the FM method, leaving some unrecorded portions in the longitudinal direction of the card. When this was read as it was using the conventional magnetic card reader / writer, all the recorded information that was written could be read. Similarly, a general magnetic card reader / writer (generated magnetic field: 5 kG) was used to newly record on the recorded portion and the unrecorded portion of the magnetic card 1, and the recorded information was read. It was confirmed that the information could not be read, and that a general card reader / writer could not overwrite the existing information and newly write to the unrecorded portion.

Next, erasure of all records on the magnetic card was performed using a magnetic head of a general magnetic card reader / writer (generated magnetic field of 5 kG), and the magnetic card after the erasing process was read using the magnetic head. It was confirmed that all existing records were erased by the erase process.

[0033]

As described above, according to the present invention,
A magnetic recording system and a magnetic recording medium having an excellent forgery prevention effect can be provided. Further, according to the present invention,
Erasing information is easy, but writing new information,
Further, it is difficult to rewrite information, and therefore it is impossible to rewrite or write information for the purpose of forgery, and to provide a magnetic recording system of a magnetic recording card, a magnetic recording medium used therefor, and a manufacturing method thereof. You can

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic card as a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a magnetic card for explaining a magnetic recording method according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a magnetic card for explaining a magnetic recording method according to another embodiment of the present invention.

FIG. 4 is a graph showing the magnetic characteristics of the magnetic powder used to manufacture the magnetic card of FIG. 1 in relation to Sm.

5 is a graph showing the magnetic characteristics of the magnetic powder used to manufacture the magnetic card of FIG. 1 in relation to Fe.

[Explanation of symbols]

 1 Magnetic Card 2 Base 3 Magnetic Layer 4 Protective Layer 5 Information Area 51 Fixed Information Area 52 Variable Information Area

Claims (4)

[Claims] 1. Information is magnetically recorded on a magnetic recording medium as a group of a plurality of recordings, and rewriting of the information is performed only by magnetically erasing a selected recording of the plurality of recordings. A magnetic recording method characterized by being performed. 2. A magnetic recording medium is provided with a fixed information area and an erase information area, fixed information is recorded in the fixed information area, and variable information is magnetically recorded in the erase information area as a group of a plurality of records. The magnetic recording method is characterized in that the variable information is recorded and rewritten only by magnetically erasing a selected one of the plurality of records. 3. The magnetic recording system according to claim 2,
The variable information is read by reading the fixed information and the variable information, processing the variable information with reference to the fixed information, and magnetically erasing a selected one of the plurality of records from the erase information area. A magnetic recording method characterized by rewriting information. 4. A magnetic recording medium having a magnetic layer provided on a substrate, wherein the magnetic layer has the general formula RaCo100-b-c-.
dFebCuZrd (where R is a rare earth element containing Sm as a main component and containing at least one or more types of Y). A magnetic recording medium comprising a magnetic powder represented by: