JP2636542B2 - Magnetic recording medium and information reading method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, such as a magnetic card, a magnetic ticket, a magnetic commuter pass, a magnetic coupon, and a magnetic sheet, on which information is recorded by a magnetic pattern.
In particular, the present invention relates to a magnetic recording medium capable of significantly increasing a forgery prevention effect by giving more information to fixed information of a magnetic pattern and a method of reading the information.

[0002]

2. Description of the Related Art In recent years, magnetic recording media such as magnetic cards, magnetic tickets, magnetic commuter passes, magnetic coupons, and magnetic sheets have been widely used in our social life. Among them, for example, a magnetic card usually has a magnetic recording layer having a thickness of about 10 to 15 μm applied on a nonmagnetic substrate having a thickness of 100 to 250 μm. Between this magnetic recording layer and the protective layer which is the top coat, a magnetic bar code which is a magnetic pattern, a concealing layer, a thermal printing layer and the like are laminated. In this case, the number of layers and the type of layers are set according to the required output and required characteristics of the magnetic card.

[0003] Of these, a magnetic barcode is a combination of a magnetic barcode containing a magnetic substance and a dummy barcode not containing a magnetic substance, so that fixed information (for example, the amount of money or the issuing institution) is stored on the card. Pattern information), that is, security is added.

FIG. 4 is a sectional view showing a configuration example of this type of magnetic card. That is, after forming the magnetic recording layer 42 on the base 41, as shown in FIG.
A magnetic barcode 43 containing a magnetic powder having a lower coercive force than the magnetic substance used for the magnetic recording layer 42 is provided by a method such as offset printing or screen printing, and a dummy barcode 44 is formed in the same manner as the magnetic barcode 43. It is provided by the method described above. Further, in a normal card, the concealing layer 4
5. The protective layer 46 is formed in the same manner as the magnetic barcode 43.

By the way, in this type of magnetic card,
Conventionally, two types of magnetic barcodes 43 have been used, and how to read them also differs depending on the type. One of them is to form a magnetic barcode 43 using a magnetic material having a coercive force that does not affect the magnetic recording layer 42 and that can sufficiently perform recording, and use the magnetic barcode 43 for the magnetic recording layer 42. This is a method of writing and reading a record in a similar manner. Examples of the magnetic material used in this case include magnetite (Fe ₃ O ₄ ) and γ-iron oxide (γ-Fe ₂ O ₃ ).

However, when the magnetic bar code 43 used in this method is applied with a commercially available magnet viewer or the like, the magnetic bar code 43 and the dummy bar code 44 can be distinguished. In order to prevent this, the information recorded on the magnetic barcode 43 must be read and then demagnetized. As a result, there is a problem that the magnetic barcode reading system becomes complicated and large. .

Therefore, in order to solve such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-109524,
There is a magnetic barcode using not a magnetic material having a coercive force used for magnetic recording, but a magnetic material which is not sensed by a magnet viewer having a low coercive force.

This is the second type, which uses carbonyl iron powder, Mn-Zn ferrite, or the like, which is a magnetic material with a low coercive force of 30 Oe or less, which is not sensed by a magnet viewer and has a low coercive force. The method of reading a magnetic barcode formed using these magnetic materials is as follows.
That is, a DC bias current is applied to the read magnetic head, and a weak DC bias magnetic field that does not affect magnetic recording is applied to the magnetic barcode. Then, the magnetic barcode having a low coercive force is magnetized by the DC bias magnetic field, and when this is read simultaneously by the reading magnetic head, an output signal waveform as shown in FIG. 5 can be obtained. In this case, since the dummy bar code portion is not magnetized, there is no output, and an output signal waveform of a specific pattern which is a combination of the magnetic bar code and the dummy bar code can be obtained.

On the other hand, in addition to the above, in order to provide security, a combination of magnetic barcodes having different coercive forces (for example, see JP-A-63-133321).
Or a combination of magnetic barcodes having different magnetization amounts (for example, JP-A-63-223892), or a magnetic material using magnetic materials having different Curie points. Various types have been proposed, such as a combination of barcodes (for example, “Japanese Utility Model Application Laid-Open No. 62-147191”), all of which are different from fixed magnetic recording in a normal magnetic recording layer. It is information, and generally, providing a magnetic barcode on a magnetic card is nothing but providing security.

[0010] However, the conventional barcode is a very simple one which only determines whether or not a barcode using a magnetic material and a barcode not using a magnetic material are mixed in a barcode. It cannot be said that the system of prevention is so effective.

[0011]

As described above, in a conventional magnetic recording medium such as a magnetic card on which a magnetic pattern is formed, only one type of output signal pattern can be obtained, so that the effect of preventing forgery is low. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and provides more information to fixed information of a magnetic pattern using a low coercive force magnetic material that is not sensed by a magnet viewer or the like. It is an object of the present invention to provide a magnetic recording medium and a method of reading information on the magnetic recording medium, which can significantly enhance the forgery prevention effect.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a magnetic recording medium on which information is recorded by a magnetic pattern containing a magnetic material. As the magnetic pattern, as a magnetic material, a magnetic pattern using a magnetic material having a low coercive force lower than an external magnetic field at the time of reading information and being saturated with an external magnetic field less than a predetermined value, and as a magnetic material, It is composed of a combination of a magnetic pattern using a magnetic material having a low coercive force lower than the magnetic field and saturated with an external magnetic field of the predetermined value or more.

Here, a dummy pattern containing no magnetic material is added.

According to the third aspect of the present invention, the magnetic material is a magnetic material having a low coercive force lower than an external magnetic field at the time of reading information and saturated with an external magnetic field less than a predetermined value. Information is obtained by a magnetic pattern composed of a combination of a magnetic pattern and a magnetic pattern using a magnetic material that is a low coercivity magnetic material lower than an external magnetic field as a magnetic material and saturates at an external magnetic field equal to or greater than the predetermined value. In a method of reading recorded information of a magnetic recording medium by passing a DC bias current to a read magnetic head, the magnitude of the DC bias current is changed so as to be sequentially increased, and at that time, the magnitude of the DC bias current is changed. The magnetic pattern is read while changing the slice level voltage so as to increase or decrease sequentially, and by the different output signal patterns, Recording, information, to perform the authenticity determination.

[0016]

Accordingly, in the magnetic recording medium and the information reading method of the present invention, the magnetic material is a low coercive force magnetic material lower than the external magnetic field at the time of reading information, and saturates with an external magnetic field less than a predetermined value. A magnetic pattern using a magnetic pattern using a magnetic material and a magnetic pattern using a magnetic material that is a magnetic material having a low coercive force lower than an external magnetic field and that is saturated with an external magnetic field equal to or more than the predetermined value as a magnetic material. And changing the magnitude of the DC bias current flowing through the read magnetic head so as to sequentially increase or decrease,
Further, at that time, by reading the magnetic pattern while changing the slice level voltage sequentially so as to correspond to the DC bias current, at least three different output signal patterns can be obtained. This allows the magnetic pattern to have more complicated recording and information than the conventional magnetic pattern, so that when it comes to counterfeiting magnetic recording media, more information can be included in the magnetic pattern than before. Thus, the security can be significantly improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a magnetic material having a low coercive force lower than an external magnetic field at the time of reading information as a magnetic material in a magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material. And a magnetic pattern using a magnetic material that saturates with an external magnetic field less than a predetermined value, and as a magnetic material, a low coercive force magnetic material lower than the external magnetic field, and saturates with an external magnetic field that is equal to or more than the predetermined value. It is composed of a combination with a magnetic pattern using a magnetic material.

That is, as described above, a magnetic pattern using a magnetic material having a low coercive force is read by passing a DC bias current through a reading magnetic head. In this case, for example, based on the experimental results shown in FIG. 3, the flowing DC bias is used for the magnetic pattern using the saturated magnetic material (A) and the magnetic pattern using the unsaturated magnetic material (B). It can be seen that the output voltage characteristics differ greatly depending on the magnitude of the current. That is, a saturated type magnetic substance (A)
In, the output voltage value shows a large value as compared with the unsaturated type magnetic material (B) at a small DC bias current and saturates. On the other hand, unsaturated type magnetic material (B)
Output voltage value increases linearly in a DC bias current within a range that does not affect the magnetic recording layer that is the base of the magnetic pattern. Therefore, if we take advantage of this property,
When a magnetic pattern is read with DC bias currents of different magnitudes, at least three types of information are read with a magnetic pattern comprising a combination of a dummy, a magnetic material of a saturated type (A), and a magnetic material of an unsaturated type (B). be able to.

In the present invention, for example, DC bias current values I ₁ , I ₂ , I ₃ (I ₁ <I ₂ <
I ₃ ), and the slice level V _{1 of} the output voltage value,
V ₂ and V ₃ (V ₁ <V ₂ <V ₃ ) are set.
Here, when the magnetic pattern is read by the combination of (I ₁ , V ₁ ), only the magnetic pattern using the saturated type magnetic material (A) is obtained as an output signal. In the combination of (I ₂ , V ₂ ), both magnetic patterns using the saturated type magnetic substance (A) and the unsaturated type magnetic substance (B) are read, and the combination of (I ₃ , V ₃ ) Then, only the magnetic pattern using the unsaturated type magnetic material (B) is read. Here, it is needless to say that the slice level V ₂ may be omitted.

As described above, by forming a magnetic pattern in the above-described configuration and reading information, at least three different output signal patterns are obtained in a magnetic pattern in which conventionally only one type of output signal can be obtained. Can be obtained.

Hereinafter, an embodiment of the present invention based on the above-described concept will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of the configuration when the present invention is applied to a magnetic card. As shown in FIG. 1, the magnetic card of the present embodiment has a base material 21, a magnetic recording layer 22 provided on the base body 21, and a plurality of magnetic patterns provided on the magnetic recording layer 22. Magnetic barcode 2
3, 24 and a dummy barcode 25, and a concealing layer 26 provided on the magnetic barcodes 23 and 24, the dummy barcode 25 and the magnetic recording layer 22 to conceal them.
And a protective layer 27 provided on the concealing layer 26. Usually, the number of layers, types of layers, layer thickness, etc.
It is set according to the required output and required characteristics of the magnetic card.

Here, the substrate 21 is formed in a card shape, and its material is, for example, polyester (PE).
T), plastics such as polyvinyl chloride and polystyrene, paper, synthetic paper and the like can be used alone or as a composite. The magnetic recording layer 22 is made of, for example, a known B
Using magnetic ink made by dispersing magnetic fine particles such as a-ferrite, Sr-ferrite, and γ-iron oxide in an appropriate resin, for example, polyurethane resin, vinyl chloride-vinyl acetate copolymer, polyester resin, etc. The magnetic ink can be formed by applying and fitting a magnetic ink by a method such as roll coating, gravure coating, screen printing and the like. In this case, as the composition of the magnetic ink, adhesion to the substrate 21 and flexibility when formed into a coating film, abrasion resistance, chemical resistance, and the like are taken into consideration.

On the other hand, the magnetic barcodes 23 and 24 are made of magnetic ink prepared by dispersing magnetic fine particles in an appropriate resin, for example, a vinyl chloride-vinyl acetate copolymer, a polyester resin or the like. Ordinary commercially available inks can be used. in this case,
The magnetic fine particles of the magnetic barcode 23 are magnetic substances having a low coercive force that cannot be detected by the magnet viewer and are saturated with an external magnetic field less than a predetermined value (for example, 5000 Oe), that is, for example, the magnetic substance 11 shown in FIG. As shown in FIG. 5, a saturated magnetic material can be used. Further, the magnetic fine particles of the magnetic barcode 24 are magnetic substances having a low coercive force that cannot be detected by the magnet viewer and are saturated with an external magnetic field of a predetermined value (for example, 5000 Oe) or more, for example, as shown in FIG. A saturated type magnetic material as shown in (12) can be used.

On the other hand, the concealing layer 26 is
3, 24, dummy barcode 25 and magnetic recording layer 22
Is an ink having high concealing properties, such as Ag, Cr, Al, Zn, and S.
A non-magnetic metal powder such as n, Pb, Cu, Bi, Ge, and In is dispersed in a binder solution and formed using an ink. Further, the protective layer 27 has a role of protecting the concealing layer 26, and as a material thereof, for example, a UV curable ink or the like can be used.

Next, an example of an actual prototype magnetic card will be described.

On a 188 μm PET film (Toray E-22) as the base material 21, Ba-ferrite 30 parts by weight Vinyl chloride-vinyl acetate copolymer resin 10 parts by weight Toluene 30 parts by weight Methyl ethyl ketone 30 parts by weight as a magnetic recording ink One part of the composition was applied by gravure coating to a thickness of 15 μm.

On the other hand, as the magnetic ink for the magnetic barcode 23 of the saturated type (A), Mn-Zn ferrite 70 parts by weight Vinyl chloride-vinyl acetate copolymer resin 10 parts by weight cyclohexanone 10 parts by weight butyl cellosolve 10 parts by weight The composition was used.

The magnetic ink for the magnetic bar code 24 of the unsaturated type (B) includes carbonyl iron powder 50 parts by weight vinyl chloride-vinyl acetate copolymer resin 20 parts by weight cyclohexanone 15 parts by weight butyl cellosolve 15 parts by weight The composition was used.

Further, as the ink for the dummy barcode 25, gray ink manufactured by Seiko Advance Co., Ltd. was used.

Using each of the above barcode inks, five (A, A, B, 5)
Dummy, A) Pattern was formed by screen printing using a screen stencil of 300 lines / inch.

On the other hand, as the ink for the concealing layer 26, an ink having a composition of 30 parts by weight of aluminum paste, 60 parts by weight of polyester resin, 5 parts by weight of cyclohexanone, and 5 parts by weight of butyl cellosolve was used. It was formed by screen printing using a screen plate.

The ink for the protective layer 27 was formed by UV dry offset printing with a thickness of 2 μm using a commercially available FDOP varnish manufactured by Toyo Ink Mfg. Co., Ltd.

After the above printing, the card was cut out to a prescribed size to produce the magnetic card of this embodiment.

The bar code portion of the magnetic card constructed as described above was measured by a magnetic bar code inspection machine (information was read).

That is, the bar code pattern is (A,
A, B, dummy, A), the magnitude of the DC bias current is I ₁ = 10 mA, I
₂ = ₃₀ mA, and I ₃ = 50 mA. The slice level voltage is changed to V ₁ = 0.6 in accordance with the DC bias current.
V, V ₂ = 1.0 V, V ₃ = 2.0 V The measurement was performed by passing through a magnetic bar code inspection machine while being changed so as to be sequentially increased. In this case, in the combination of (10 mA, 0.6 V), the output signal pattern was as shown by I ₁ −V ₁ in FIG. 2, and the signal was (11001). Further, in the combination of (30 mA, 1.0 V), the output signal pattern becomes as shown by I ₂ −V ₂ in FIG.
A signal (11101) was obtained. In addition, (50m
A, 2.0 V), the output signal pattern is as shown by I ₃ −V ₃ in FIG.
100) was obtained.

Thus, the bar code is read as described above, and recording, information, and authenticity determination can be performed based on the different output signal patterns. That is,
The difference between the output voltage levels causes the reading method and the recognition method corresponding to the pattern to be set in advance as shown in FIG. 2 so that the validity of the magnetic card can be known. If there is no difference between the output voltage levels, it is not the corresponding magnetic card.

As described above, in this embodiment, the base material 21
A magnetic recording layer 22 provided on the base 21; a plurality of magnetic barcodes 23 and 24 and a dummy barcode 25 which are magnetic patterns provided on the magnetic recording layer 22; 24, a dummy bar code 25, and a magnetic card including a concealing layer 26 provided on the magnetic recording layer 22 for concealing them, and a protective layer 27 provided on the concealed layer 26. As a magnetic material, a magnetic material having a low coercive force that cannot be detected by a magnet viewer, and
A magnetic material that saturates in an external magnetic field of less than 000 Oe is used. As a magnetic material of the magnetic barcode 24, a magnetic material that is a low coercive force that cannot be detected by a magnet viewer and saturates in an external magnetic field of 5000 Oe or more is used. When reading a recorded information by supplying a DC bias current to a reading magnetic head, the magnitude of the DC bias current I is changed so as to be sequentially increased. The barcodes 23, 24, and 25 are read while changing the slice level voltage V so as to sequentially increase in accordance with I, and recording, information, and authenticity determination are performed based on the different output signal patterns. is there.

Therefore, conventionally, only one type of output signal pattern could be provided, but the magnetic card of this embodiment can have at least three types of output signal patterns. This allows the magnetic pattern to have more complicated recording and information than conventional magnetic barcodes.
More information can be included in the magnetic pattern than in the prior art, and security can be significantly improved. This makes it possible to significantly improve the forgery prevention effect. In other words, by falsifying or falsifying data for one or two magnetic recording methods by using a read method and a recognition method using a reproduced output voltage level corresponding to the pattern by patterning the output signal. Has a very high anti-counterfeiting effect.

It should be noted that the present invention is not limited to the above-described embodiment, but can be similarly implemented in the following manner.

In each of the above embodiments, the case where three types of output signal patterns are obtained by changing the magnitudes of the DC bias current and the slice level voltage in three steps has been described. It is also possible to obtain a signal pattern.

In each of the above embodiments, the case where a magnetic bar code is provided has been described. However, the present invention is not limited to this, and if the magnetic bar code has a specific magnetic pattern, the output signal may be more complicated than the conventional one by the same method as described above. A pattern can be obtained.

Further, in each of the above embodiments, the case where information is read by changing the DC bias current and the slice level voltage so as to be sequentially increased has been described. However, the DC bias current and the slice level voltage are not limited thereto. It is also possible to read information by changing the level voltage so as to decrease the magnitude sequentially.

[0044]

As described above, according to the present invention, in a magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material, a magnetic material is used as a magnetic pattern when reading information. A magnetic pattern using a magnetic material that is a low coercive force lower than the magnetic field and saturated with an external magnetic field less than a predetermined value, and as a magnetic material, a low coercive force magnetic material lower than the external magnetic field, and Composed of a combination with a magnetic pattern that uses a magnetic material that saturates with an external magnetic field that is greater than or equal to a predetermined value.When a DC bias current is passed to the read magnetic head to read recorded information, the magnitude of the DC bias current is sequentially increased. Alternatively, the magnetic pattern is changed while decreasing so as to sequentially increase the slice level voltage corresponding to the DC bias current at that time. The recording, information, and authenticity are determined based on the different output signal patterns, so more information can be stored in the fixed information of the magnetic barcode using a low-coercivity magnetic material that is not detected by a magnet viewer or the like. Thus, a magnetic recording medium and a method of reading information thereof, which can significantly enhance the forgery prevention effect, can be provided.

[Brief description of the drawings]

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

FIG. 2 is a waveform chart showing an example of an output signal pattern of a magnetic barcode in the embodiment.

FIG. 3 is a characteristic diagram showing an example of a relationship between a DC bias current and an output voltage value for explaining the concept of the present invention.

FIG. 4 is a sectional view showing a configuration example of a conventional magnetic card.

FIG. 5 is a waveform chart showing an example of an output signal pattern of a conventional magnetic barcode.

[Explanation of symbols]

21: Base, 22: Magnetic recording layer, 23, 24: Magnetic barcode, 25: Dummy barcode, 26: Concealment layer, 27
... Protective layer.

Claims (3)

(57) [Claims] 1. A magnetic recording medium on which information is recorded by a magnetic pattern containing a magnetic material, wherein the magnetic pattern is a magnetic material having a low coercive force lower than an external magnetic field at the time of reading information. There is a magnetic pattern using a magnetic material that saturates with an external magnetic field less than a predetermined value, and a magnetic material that is a low coercive force magnetic material lower than the external magnetic field and saturates with an external magnetic field that is equal to or more than the predetermined value. A magnetic recording medium comprising a combination with a magnetic pattern using a body. 2. The magnetic recording medium according to claim 1, wherein a dummy pattern containing no magnetic material is added. 3. A magnetic pattern using a magnetic material having a low coercive force lower than an external magnetic field and being saturated by an external magnetic field less than a predetermined value as a magnetic material; Information of a magnetic recording medium in which information is recorded by a magnetic pattern composed of a combination of a magnetic pattern using a magnetic material that is a low coercive force magnetic material lower than a magnetic field and saturates with an external magnetic field of the predetermined value or more. In a reading method in which a direct current bias current is passed through the read magnetic head, the magnitude of the direct current bias current is changed so as to be sequentially increased, and at that time, the slice level voltage is sequentially increased corresponding to the direct current bias current. Alternatively, the magnetic pattern is read while being changed so as to decrease, and recording,
A method for reading information on a magnetic recording medium, characterized in that information and authenticity are determined.