JPH08161735A - Magnetic recording system, magnetic card and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a magnetic recording system of a magnetic card and a manufacturing method thereof which achieves anti-forging effect while existing information is kept hard to be erased and a characteristic of allowing new recording with a low coercive force while the information after recorded is kept hard to be erased. CONSTITUTION: A magnetic card 1 has on a base body 2 a magnetic layer 3 on which is applied a magnetic paint containing a magnetic powder and the magnetization characteristic of the magnetic powder is such that saturation magnetization exceeds 25% by an applied magnetic field equivalent to less than a half of a coercive force. The magnetic paint is as given by a formula of Ra Co(100-a-b-c-d) Feb Cuc Zrd (wherein R represents rate earth element containing at least one kind of Y with Sm as main component with a=10.0-13.5at%, b=17.5-22.0at%. c=2.0-8.0at% and d=0.5-3.5at%). When initial information is recorded on the magnetic card by a system of magnetic recording in the longitudinal direction within the surface of the magnetic card, one part yet to be recorded is left and when new information is recorded sequentially, the information is recorded at the part yet to be recorded without deleting the existing information.

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 for a magnetic card having a magnetic layer, a magnetic card and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as one kind 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 has a magnetic layer for recording information on a substrate such as resin or paper.

Then, every time the magnetic card is used in a predetermined device, the content of the information already magnetically recorded in the magnetic layer is rewritten.

The information recorded on the magnetic layer of this type of magnetic card can usually be read by a magnetic viewer or the like. This may lead to 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 a multilayer magnetic layer, or punching a magnetic card for each use.

The substrate of the magnetic card is made of polyethylene terephthalate (PET) resin or paper, for example. On the other hand, in the conventional magnetic layer, a magnetic paint in which magnetic powder of barium ferrite with 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 applying to.

[0007]

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, Information can be written easily. For this reason, the conventional magnetic card has a drawback that it cannot effectively prevent forgery and alteration. Specifically, all information including new information generated each time the magnetic card is used is overwritten on the old information and is rewritten each time. Therefore, if there is a device that records / reproduces the information on the card. It is possible to easily rewrite information and forge the recorded contents of 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, information can be easily rewritten by the conventional magnetic recording / reproducing apparatus, and the magnetic 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 magnetic head. If the coercive force of this magnetic layer is larger than this, rewriting (overwriting) cannot be performed.

That is, the problem with the prior art is that, every time a magnetic card is used, the existing record information is overwritten so that the existing record information is erased and new information such as the remaining amount and the used amount is written. Are using. If the coercive force of the magnetic layer of the magnetic card is large, the conventional magnetic recording / reproducing device cannot record new information.

Therefore, the first technical problem of the present invention is
(EN) Provided are a magnetic recording system and a magnetic card which have an excellent anti-counterfeiting effect, in which information can be easily recorded without preparing a special magnetic recording / reproducing device and existing information is hard to erase, and a manufacturing method thereof. Especially.

A second technical object of the present invention is to provide a magnetic card having a magnetic recording layer which has a low coercive force and excellent characteristics for new recording, and has a characteristic that it is difficult to erase recorded information once recorded. A magnetic recording method, a magnetic card used for the magnetic recording method, and a method for manufacturing the same are provided.

[0013]

According to the present invention, there is provided a magnetic recording system for magnetic recording in a longitudinal direction of a magnetic recording medium of a magnetic card, wherein the magnetic card has a coercive force of 1 A magnetic layer coated with a magnetic paint containing a magnetic powder having a magnetization of 25% or more of the saturation magnetization at an applied magnetic field of ½ or less, wherein the magnetic powder has a general formula of RaCo _(100-abcd) F
e _b Cu _c Zr _d (where R is a rare earth element containing Sm as a main component and containing at least one type of Y, and the ratio of each component is a = 10.0 to 13.5 at% and b = 17.5). ~ 2
2.0 at%, c = 2.0 to 8.0 at%, d = 0.5
˜3.5 at%), and when recording the initial information on the magnetic card, magnetic recording is performed while leaving at least one unrecorded portion in the longitudinal direction, and then the magnetic card is used. When recording new information for each time, by recording new information in the unrecorded portion without erasing existing information, it is easy to record information when recording information. A magnetic recording system is obtained which is characterized in that it is difficult to erase or rewrite recorded information.

Further, according to the present invention, in a magnetic card provided with a magnetic recording layer for magnetically recording in the longitudinal direction of the surface, the magnetic recording layer has a coercive force of 1/2 of the coercive force provided on the base of the magnetic card. comprising a magnetic layer formed from the coated magnetic powder having more than 25% of the magnetization of saturation magnetization in the following applied magnetic field, the magnetic powder has the general formula _{RaCo (100-abcd) Fe b} Cu
_c Zr _d (where R is at least 1 whose main component is Sm)
It is a rare earth element containing Y, and the ratio of each component is a = 1.
0.0-13.5 at%, b = 17.5-22.0 at
%, C = 2.0 to 8.0 at%, d = 0.5 to 3.5a
The magnetic card is characterized in that it is easy to record the information when recording the information on the magnetic card, but it is difficult to erase or rewrite the recorded information. can get.

According to the present invention, in the method for producing the magnetic powder used for the magnetic card, the ingot obtained by melting each element as shown by the chemical composition of the general formula is obtained by crushing. A method for producing magnetic powder characterized by the above is obtained.

Here, in the present invention, the ingot is crushed in vacuum or in an inert gas before crushing.
The heat treatment is preferably performed at a temperature of 50 ° C to 950 ° C.

According to the present invention, there is provided a method of manufacturing a magnetic card for magnetically recording in a longitudinal direction of a magnetic recording medium, wherein saturation magnetization is applied on a substrate of the magnetic card with an applied magnetic field of 1/2 or less of coercive force. Forming a magnetic layer by applying a magnetic coating material containing magnetic powder having a magnetization of at least 25% of
The magnetic powder has the general formula _{RaCo (100-abcd) Fe b} C
u _c Zr _d (where R is a rare earth element containing Sm as a main component and containing at least one type of Y, and the ratio of each component is a =
10.0-13.5 at%, b = 17.5-22.0a
t%, c = 2.0 to 8.0 at%, d = 0.5 to 3.5
The magnetic card is characterized in that at the time of recording information, the information can be easily recorded, but it is difficult to erase or rewrite the recorded information. A method is obtained.

Here, in the method for manufacturing a magnetic card of the present invention, the magnetic powder is obtained by crushing an ingot obtained by melting each element as shown in the chemical composition of the general formula. Is preferably used. In the method for manufacturing a magnetic card according to the present invention, the ingot may be crushed in a vacuum or an inert gas before being crushed.
It is more preferable to perform the heat treatment at a temperature of 0 ° C to 950 ° C.

In the present invention, existing recorded information is hard to erase and new information can be easily recorded on the magnetic layer, and the magnetic card using the magnetic layer has an unrecorded portion. The magnetic recording method is adopted so that new information can be recorded in that area.

[0020]

In the magnetic card of the present invention, since the magnetic layer is formed by using the magnetic powder having the above composition, its magnetic characteristic is that the rising of the magnetic flux is quick and magnetic recording can be easily performed.

However, demagnetization is difficult and effective in preventing falsification and forgery of information once recorded.

[0022]

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

FIG. 1 is a sectional view of a magnetic card according to an embodiment of the present invention. The magnetic card 1 is used as a ticket such as a ticket, a telephone card, or a prepaid card. This magnetic card 1 has a magnetic layer 3 formed on a main surface of a substrate 2 made of polyethylene terephthalate (PET) resin by applying a magnetic paint, and a protective layer 4 is further formed on the magnetic layer 3 if necessary. It was formed.

FIG. 2 is a plan view seen from the surface of the magnetic layer 3 for explaining the magnetic recording method according to the embodiment of the present invention. The magnetic layer 3 of the magnetic card 1 is provided with a stripe-shaped information recording area 5 extending between both ends in the longitudinal direction of the magnetic card 1. The information recording area 5 is described in FIG. 2 so that it can be clearly viewed for the sake of convenience, but it is provided in a form that cannot be viewed in reality.

In the information recording area 5, recording information as initial information is magnetically recorded as a group of a plurality of recordings adjacent in the longitudinal direction. Specifically, the information of the magnetic card 1, for example, the number of records corresponding to the amount of money is recorded in the information recording area 5 in the state of being adjacent in the longitudinal direction. Therefore, the portion of the information recording area 5 where the information has already been recorded is shown by hatching.

An existing information recording area 51 and an unrecorded information recording area 52 are adjacent to the information recording area 5 in the longitudinal direction.
Are provided. Fixed information is recorded in the existing information recording area 51. When sequentially recording new information each time the magnetic card is used, new information is recorded in the unrecorded information recording area 52 without erasing the recorded information in the existing information recording area 51. Although it is difficult to rewrite the variable information in the information recording area 52 of the unrecorded portion, which is once recorded, it is performed only by magnetically erasing a selected record among a plurality of records. In this case, the magnetic recording / playback device reads the existing fixed information and variable information,
The processing circuit refers to the existing fixed information and performs a predetermined process on the variable information, and then the magnetic recording / reproducing apparatus magnetically selects a selected recording from the plurality of recordings from the unrecorded information recording area 52. The variable information can be rewritten by erasing.

Next, the magnetic coating material containing the magnetic powder for forming the magnetic layer 3 of the magnetic card 1 will be specifically described.

Sm, Co, Fe, C having a purity of 99% or more
u and Zr are dissolved, and the composition value of Sm is 9.0 to 15.0.
at%, Fe composition value is 16.0 to 23.0 at%, C
An alloy ingot having a composition in which the composition value of u is 1.0 to 10.0 at%, the composition value of Zr is 0.2 to 4.0 at%, and the composition value of Co is bal is produced. Then, this ingot was homogenized at a temperature of 1195 ° C. for 12 hours or more in an Ar gas atmosphere. Then, 750 ° C to 950
After holding at a temperature of ° C for a predetermined time, the ingot was crushed using a disc mill to obtain a coarse powder. Next, this coarse powder was further pulverized using a vortex to obtain an average particle size of 2.0.
˜3.0 μm powder was obtained. The magnetic characteristics of these powders were measured using a vibrating sample magnetometer (VSM), and the results are shown in FIGS.

In the composition value of the above alloy, as shown in FIG. 3, the ratio of the composition value of Sm has a great influence on the coercive force of the magnetic layer, and when it is 10.0 at% or less, the coercive force Hcj decreases,
It becomes easy to erase the recorded information. On the other hand, when the composition value ratio of Sm is 13.5 at% or more, the magnetizability decreases, and magnetic recording (magnetism) becomes difficult. In the figure, B5 / B1
8 (%) shows that the magnetization in the initial magnetization curve is square.

Similarly, as shown in FIG. 4, when the Fe composition value is 17.5 at% or less, the coercive force Hcj decreases, and
If it is 2.0 at% or more, the magnetizability decreases.

Similarly, as shown in FIG. 4, when the Cu composition value is 2.0 at% or less, the coercive force Hcj decreases to 8.0.
When it is at% or more, the magnetizability decreases.

Similarly, as shown in FIG. 3, when the composition value of Zr is 0.5 at% or 3.5 at% or more, the coercive force H is
cj decreases, it becomes easy to erase the magnetically recorded information, and there is a risk of tampering with the information. A magnetic coating material having the composition shown in Table 1 below was obtained using the magnetic powder having the above composition value range.

[0033]

[Table 1]

Further, as shown in FIG. 1, the magnetic coating described above was applied onto the base 2 made of PET resin, and the magnetic coating was applied so as to have a thickness of 20 μm. Card 1 was created.

On the magnetic layer 3 of the magnetic card 1 thus obtained, a magnetic head (generated magnetic field of 5 kG) was used, and some unrecorded portions were left in the longitudinal direction of the card, and recording was performed by, for example, the FM system. . When this was read as it was using the conventional magnetic card reader / writer, all the recorded information that was written could be read. Next, erasure of all recordings 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 not erased by the erasing process.

When new information was recorded in the longitudinal direction of the card using a general magnetic head, existing recorded information was not erased and new information could be easily recorded in the unrecorded portion.

[0037]

As described above, according to the present invention,
It is possible to provide a magnetic layer in which information can be newly written or rewritten easily, while erasing information is difficult.

Further, according to the present invention, it is possible to provide a magnetic recording method for a magnetic card in which information cannot be rewritten or written for the purpose of forgery, a magnetic recording medium used therefor and a manufacturing method thereof.

[Brief description of drawings]

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

FIG. 2 is a plan view of a magnetic card according to an embodiment of the present invention.

3 is a graph showing the relationship between the magnetic properties of the magnetic powder used to manufacture the magnetic card of FIG. 1 and the composition values of Sm and Zr.

FIG. 4 is a graph showing the relationship between the magnetic properties of the magnetic powder used to manufacture the magnetic card of FIG. 1 and the composition values of Fe and Cu.

[Explanation of symbols]

 1 magnetic card 2 substrate 3 magnetic layer 4 protective layer 5 information recording area 51 existing information recording area 52 information recording area of unrecorded portion

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masaya Kawabe 6-7 Koriyama, Taichiro-ku, Sendai, Miyagi Prefecture Tokin Co., Ltd.

Claims (7)

[Claims] 1. A method of magnetically recording in a longitudinal direction of a magnetic recording medium of a magnetic card, wherein the magnetic card has a saturation magnetization at an applied magnetic field of 1/2 or less of a coercive force formed on a substrate. A magnetic layer coated with a magnetic coating material containing magnetic powder having a magnetization of 25% or more is used, and the magnetic powder has the general formula Ra
Co _(100-abcd) Fe _b Cu _c Zr _d (where R is S
A rare earth element containing m as a main component and containing at least one type of Y, and the ratio of each component is a = 10.0 to 13.5 at
%, B = 17.5 to 22.0 at%, c = 2.0 to 8.
0 at%, d = 0.5 to 3.5 at%), and when the initial information is recorded on the magnetic card, magnetic recording is performed while leaving at least one unrecorded portion in the longitudinal direction. , After that, each time a magnetic card is used, when new information is sequentially recorded, the new information is recorded in an unrecorded portion without erasing the existing information. The magnetic recording method is characterized in that it is easy to record, but it is difficult to erase or rewrite the recorded information. 2. A magnetic card provided with a magnetic recording layer for magnetic recording in the longitudinal direction of the plane, wherein the magnetic recording layer is saturated with an applied magnetic field of 1/2 or less of a coercive force provided on the base of the magnetic card. A magnetic layer made of coated magnetic powder having a magnetization of 25% or more, the magnetic layer having the general formula R
_{aCo (100-abcd) Fe b} Cu c Zr d ( where R is a rare earth element including at least one Y mainly comprising Sm, the ratio of each component, a = 10.0~13.5at
%, B = 17.5 to 22.0 at%, c = 2.0 to 8.
0at%, d = 0.5 to 3.5at%), and when the information is recorded on the magnetic card, the information can be easily recorded, but the recorded information can be erased and rewritten. A magnetic card characterized by difficulty. 3. The method for producing magnetic powder for use in a magnetic card according to claim 2, which is obtained by crushing an ingot obtained by melting each element as shown in the chemical composition of the general formula. A method for producing magnetic powder, characterized in that 4. The method for producing magnetic powder according to claim 3, wherein the ingot is subjected to heat treatment at a temperature of 750 ° C. to 950 ° C. in a vacuum or an inert gas before crushing. Production method. 5. A method of manufacturing a magnetic card for magnetically recording in a longitudinal direction of a magnetic recording medium, wherein at least 25% of saturation magnetization is applied to a substrate of the magnetic card at an applied magnetic field of 1/2 or less of coercive force. Forming a magnetic layer by applying a magnetic coating material containing magnetic powder having the magnetization of
Formula RaCo in _{(100-abcd) Fe b Cu} c Zr d ( wherein R is a rare earth element including at least one Y mainly comprising Sm, the ratio of each component, a = 10.0 to 1
3.5 at%, b = 17.5 to 22.0 at%, c =
2.0 to 8.0 at%, d = 0.5 to 3.5 at%). When the information is recorded on the magnetic card, the information can be easily recorded, but the recorded information is recorded. Is a method for manufacturing a magnetic card, characterized in that it is difficult to erase and rewrite. 6. The method for manufacturing a magnetic card according to claim 5, wherein the magnetic powder is obtained by crushing an ingot obtained by melting each element as shown in the chemical composition of the general formula. A method for manufacturing a magnetic card, characterized in that a magnetic card is used. 7. The magnetic card manufacturing method according to claim 6, wherein the ingot is heat-treated at a temperature of 750 ° C. to 950 ° C. in a vacuum or an inert gas before crushing. Manufacturing method.