JPH04301213A - Magnetic recording medium and information reading method for the same - Google Patents

Abstract

PURPOSE:To improve a forgery preventive effect by giving information to a magnetic bar code using the magnetic material of low coercive force not detected by a magnet viewer, etc., and reading a magnetic pattern from it as changing voltage. CONSTITUTION:The magnetic material which is the low coercive force magnetic material of an extent not detected by the magnet viewer and is saturated by an external magnetic field below 5000Oe is used as the magnetic material of the magnetic bar code 23. The magnetic material which is the low coercive force magnetic material not detected by the magnet viewer and in addition, is saturated by the external magnetic field over 5000Oe is used as the magnetic material for the magnetic bar code 24. In the case that the recorded information is read by flowing a DC bias current in a reading magnetic head, the bar codes 23, 24, 25 are read as changing slice level voltage so as to increase it successively, and the truth or the falseness of the recorded information is judged by these different output signal patterns. Thus, the forgery preventive effect can be remarkably improved.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to magnetic recording media such as magnetic cards, magnetic tickets, magnetic commuter passes, magnetic coupon tickets, magnetic sheets, etc., in which information is recorded using magnetic patterns.
In particular, the present invention relates to a magnetic recording medium and a method for reading information from the magnetic recording medium in which a large amount of information is given to the fixed information of a magnetic pattern, thereby significantly increasing the anti-counterfeiting effect.

0002

2. Description of the Related Art In recent years, magnetic recording media such as magnetic cards, magnetic tickets, magnetic commuter passes, magnetic coupon tickets, and magnetic sheets have come into widespread use in our social lives. Among these, for example, in the case of a magnetic card, a magnetic recording layer with a thickness of about 10 to 15 μm is usually coated on a nonmagnetic substrate with a thickness of 100 to 250 μm. Laminated between this magnetic recording layer and the protective layer, which is a top coat, are a magnetic barcode, which is a magnetic pattern, a hiding layer, a thermal printing layer, and the like. In this case, the number of layers and the type of layers are set depending on the required output and required characteristics of the magnetic card.

Among these, magnetic barcodes are a combination of a magnetic barcode that contains a magnetic material and a dummy barcode that does not contain a magnetic material. pattern information), that is, security is added.

FIG. 4 is a sectional view showing an example of the structure of this type of magnetic card. That is, as shown in FIG. 4, in the magnetic card, after forming the magnetic recording layer 42 on the base 41,
A magnetic barcode 43 containing magnetic powder with a coercive force lower than that of the magnetic material used in the magnetic recording layer 42 is provided by a method such as offset printing or screen printing, and a dummy barcode 44 is provided in the same manner as the magnetic barcode 43. Provided in the following manner. Furthermore, in a normal card, there is a hidden layer 45 on top of this.
, the protective layer 46 is formed by the same method as the magnetic barcode 43.

By the way, in this kind of magnetic card,
Conventionally, two types of magnetic barcodes 43 have been used, and the way they are read differs depending on the type. One method is to form the magnetic barcode 43 using a magnetic material that has a coercive force that does not affect the magnetic recording layer 42 and is sufficient for recording. This is a method for writing and reading records in a similar manner. Examples of magnetic materials used in this case include magnetite (Fe3 O4) and γ-iron oxide (γ-Fe2 O3).

However, the magnetically recorded magnetic barcode 43 used in this method can be distinguished from the dummy barcode 44 by applying a commercially available magnet viewer or the like. In order to prevent this, it is necessary to demagnetize the magnetic barcode 43 after reading the information recorded on it, which poses a problem in that the magnetic barcode reading system becomes complicated and large. .

[0007] In order to solve this problem, for example, as shown in "Japanese Unexamined Patent Publication No. 1-109524",
There are magnetic barcodes that are not made of magnetic materials with coercive force like those used for magnetic recording, but are made of magnetic materials that have even lower coercive force and cannot be detected by magnetic viewers.

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

On the other hand, in addition to the above, in order to provide security, magnetic barcodes with different coercive forces are combined (for example, "Japanese Patent Application Laid-Open No. 133321/1983").
, or “Japanese Patent Application Laid-Open No. 63-308724”), combinations of magnetic barcodes with different amounts of magnetization (for example,
Various types of barcodes have been proposed, such as "Japanese Unexamined Patent Publication No. 63-223892") and combinations of magnetic barcodes using magnetic materials with different Curie points (for example, "Japanese Utility Model Application No. 147191/1983"). ing. All of these pieces of information are fixed information that is different from magnetic recording in a normal magnetic recording layer, and generally, providing a magnetic barcode on a magnetic card is nothing but providing security.

[0010] However, conventional barcodes are very simple, and only determine whether barcodes that use magnetic materials and those that do not use magnetic materials coexist. It cannot be said that it is very effective as a prevention system.

[0011]

[Problems to be Solved by the Invention] As described above, in magnetic recording media such as magnetic cards on which conventional magnetic patterns are formed, only one type of output signal pattern can be obtained, so the effectiveness in preventing counterfeiting is low. There was a problem.

The present invention has been made to solve the above-mentioned problems, and it provides more information to the fixed information of the magnetic pattern using a magnetic material with a low coercive force that is not detected by a magnet viewer, etc. It is an object of the present invention to provide a magnetic recording medium and a method for reading information from the magnetic recording medium that can significantly improve the anti-counterfeiting effect.

[0013]

[Means for Solving the Problems] In order to achieve the above object, firstly, in the invention according to claim 1, in a magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material, The above-mentioned magnetic pattern includes a magnetic pattern using a magnetic material with a low coercive force lower than the external magnetic field at the time of information reading, and which saturates in an external magnetic field less than a predetermined value, and an external magnetic material as the magnetic material. It is composed of a combination with a magnetic pattern using a magnetic material that is a low coercive force magnetic material that is lower than the magnetic field and is saturated by an external magnetic field that is equal to or greater than the above-mentioned predetermined value.

[0014] Here, a dummy pattern that does not contain any magnetic material is added.

[0015] Furthermore, in the invention as set forth in claim 3, the magnetic material is a low coercivity magnetic material that is lower than the external magnetic field during information reading, and is saturated with an external magnetic field less than a predetermined value. Information is transmitted by a magnetic pattern composed of a combination of a magnetic pattern and a magnetic pattern using a magnetic material having a low coercive force lower than that of an external magnetic field and saturated by an external magnetic field equal to or higher than the predetermined value. A method of reading recorded information on a magnetic recording medium by passing a DC bias current through a reading magnetic head, in which the magnitude of the DC bias current is sequentially increased and corresponds to the DC bias current at that time. The magnetic pattern is read while sequentially increasing or decreasing the slice level voltage, and recording, information, and authenticity determination are performed based on the different output signal patterns.

[0016]

[Operation] Therefore, in the magnetic recording medium and the information reading method of the present invention, the magnetic material is a low coercivity magnetic material that is lower than the external magnetic field at the time of information reading, and is saturated in the external magnetic field less than a predetermined value. A magnetic pattern is created from a combination of a magnetic pattern using a magnetic material and a magnetic pattern using a magnetic material that is a low coercivity magnetic material that is lower than the external magnetic field and is saturated in the external magnetic field of the predetermined value or more. and sequentially increases or decreases the magnitude of the DC bias current flowing through the reading magnetic head,
Furthermore, by reading the magnetic pattern while sequentially increasing the slice level voltage in response to the DC bias current, it is possible to obtain at least three different output signal patterns. This allows the magnetic pattern to contain more complex records and information than conventional magnetic patterns, so when it comes to counterfeiting magnetic recording media, it is possible to include more information in the magnetic pattern than before. , it is possible to significantly improve security.

[0017]

[Example] The present invention uses a low coercive force magnetic material, which is lower than the external magnetic field when reading information, as a magnetic pattern in a magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material. A magnetic pattern using a magnetic material that saturates in an external magnetic field that is less than a predetermined value, and a magnetic material that uses a low coercive force magnetic material that is lower than the external magnetic field and saturates in an external magnetic field that is greater than or equal to the predetermined value. It is constructed from a combination with a magnetic pattern using a magnetic material.

That is, a magnetic pattern using a magnetic material with a low coercive force is read by passing a DC bias current through the reading magnetic head, as described above. In this case, for example, based on the experimental results shown in FIG.
) and an unsaturated type magnetic material (B
), it can be seen that the output voltage characteristics differ greatly depending on the magnitude of the DC bias current applied. That is, in the saturated type magnetic material (A), the output voltage value exhibits a larger value than that of the unsaturated type magnetic material (B) at a small DC bias current, and is saturated. On the other hand, the output voltage value of the unsaturated type magnetic material (B) increases linearly in a DC bias current range that does not affect the magnetic recording layer underlying the magnetic pattern. Therefore, if such a property is used, when a magnetic pattern is read with different magnitudes of DC bias current, a magnetic pattern consisting of a combination of a dummy, a saturated type magnetic material (A), and an unsaturated type magnetic material (B) can be obtained. in,
At least three types of information can be read.

In the present invention, for example, the DC bias current values I1, I2, I3 (I1 < I2
<I3), and the slice level V1 of the output voltage value
, V2, and V3 (V1 <V2 <V3), respectively. Here, when a magnetic pattern is read using the combination of (I1, V1), only the magnetic pattern using the saturation type magnetic material (A) is obtained as an output signal. In addition, in the combination of (I2, V2), both magnetic patterns using saturated type magnetic material (A) and unsaturated type magnetic material (B) are read, and (I3, V3)
With this combination, only the magnetic pattern using the unsaturated type magnetic material (B) is read. It goes without saying that the slice level V2 can be omitted here.

As described above, by forming a magnetic pattern with the above-described configuration and reading information, it is possible to obtain at least three different types of output signal patterns from the magnetic pattern, which conventionally only provided an output signal of one type. can be obtained.

An embodiment of the present invention based on the above concept will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of the structure when the present invention is applied to a magnetic card. As shown in FIG. 1, the magnetic card of this embodiment includes a base material 21, a magnetic recording layer 22 provided on the base material 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, 24, the dummy barcode 25, and the magnetic recording layer 22 to hide them.
and a protective layer 27 provided on the concealing layer 26. In addition, the number of layers, type of layers, layer thickness, etc. are usually as follows:
It is set depending on the required output and characteristics of the magnetic card.

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

On the other hand, the magnetic barcodes 23 and 24 use magnetic ink made by dispersing magnetic fine particles in a suitable resin, such as vinyl chloride-vinyl acetate copolymer, polyester resin, etc., and the dummy barcode 25 uses , ordinary commercially available inks can be used. in this case,
The magnetic fine particles of the magnetic barcode 23 are a magnetic material with a low coercive force that is not detected by a magnet viewer and is saturated in an external magnetic field of less than a predetermined value (for example, 5000 Oe), that is, for example, the magnetic material 11 in FIG. 3 described above. A saturation type magnetic material as shown in can be used. Further, the magnetic fine particles of the magnetic barcode 24 are a magnetic material with a low coercive force that is not detected by a magnet viewer, and is a magnetic material that is saturated by an external magnetic field of a predetermined value (for example, 5000 Oe) or more, that is, for example, as shown in FIG. A saturation type magnetic material as shown in No. 12 can be used.

On the other hand, the concealing layer 26 includes the magnetic barcode 23
, 24, to hide the dummy barcode 25 and the magnetic recording layer 22 so that they cannot be visually identified, and ink with high hiding properties, such as Ag, Cr, Al, Zn, Sn.
, Pb, Cu, Bi, Ge, In, and other non-magnetic metal powders are dispersed in a binder solution. Further, the protective layer 27 has a role of protecting the concealing layer 26, and its material is, for example, U.
V-curable ink or the like can be used.

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

A 188 μm PET film (Toray E-22), which is the base material 21, was coated with magnetic recording ink.
Ba-ferrite
30 parts by weight
Vinyl chloride-vinyl acetate copolymer resin
10 parts by weight
toluene
30
Parts by weight Methyl ethyl ketone
A composition of 30 parts by weight was applied to a thickness of 15 μm by gravure coating.

On the other hand, as the magnetic ink for the magnetic barcode 23 which is the saturation type (A), Mn-Zn ferrite is used.
70 parts by weight
Vinyl chloride-vinyl acetate copolymer resin
10 parts by weight
cyclohexanone
10 parts by weight Butyl cellosolve

A composition of 10 parts by weight was used.

Furthermore, as the magnetic ink for the unsaturated type (B) magnetic barcode 24, carbonyl iron powder is used.
50 parts by weight Vinyl chloride-vinyl acetate copolymer resin
20 parts by weight
cyclohexanone
15
Part by weight Butyl cellosolve

A composition of 15 parts by weight was used.

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

[0031] Using each of the above barcode inks, a screen plate with a width of 1 mm and a length of 5 mm with a pattern of 5 lines (A, A, B, dummy, A) and a rate of 300 lines/inch was made. It was formed by screen printing.

On the other hand, as the ink for the hiding layer 26,
aluminum paste
30 parts by weight polyester resin
60 parts by weight cyclohexanone

5 parts by weight Butyl cellosolve
5 parts by weight
A material with a composition of 20
It was formed by screen printing using a 0 lines/inch screen plate.

As the ink for the protective layer 27, a commercially available FDOP varnish manufactured by Toyo Ink Manufacturing Co., Ltd. was used, and the protective layer 27 was formed to a thickness of 2 μm by UV dry offset printing.

[0034] After the above printing, the magnetic card of this example was manufactured by punching out the card to the specified size.

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

That is, the barcode pattern is (A,
For the magnetic cards A, B, dummy, and A), the magnitude of the DC bias current is I1 = 10 mA, I
2 = 30 mA, I3 = 50 mA, and at that time, the magnitude of the slice level voltage is changed to V1 = 0 in accordance with the DC bias current.
．． 6V, V2 = 1.0V, and V3 = 2.0V, which were successively increased, while being passed through a magnetic barcode inspection machine and measured. In this case, (10mA, 0.6V)
In the combination of , the output signal pattern is I1 in FIG.
-V1, and a signal (11001) was obtained. Further, in the combination of (30 mA, 1.0 V), the output signal pattern became as shown in I2-V2 in FIG. 2, and the signal (11101) was obtained. Furthermore, in the combination of (50mA, 2.0V),
The output signal pattern was as shown in I3-V3 in FIG. 2, and the signal (00100) was obtained.

[0037] Therefore, barcodes can be read in the manner described above, and recording, information, and authenticity determination can be performed based on the different output signal patterns. In other words, when a difference occurs in the output voltage level, by setting the reading method and recognition method corresponding to that pattern in advance as shown in Figure 2, it is possible to know the validity of the magnetic card. If a difference in output voltage level does not occur in accordance with the pattern, it means that the magnetic card is not the one in question.

As mentioned above, in this embodiment, the base material 21
, a magnetic recording layer 22 provided on this base 21 , a plurality of magnetic barcodes 23 , 24 and a dummy barcode 25 which are magnetic patterns provided on this magnetic recording layer 22 , and these magnetic barcodes 23 , 24. In a magnetic card consisting of a concealing layer 26 provided on a dummy barcode 25 and a magnetic recording layer 22 to conceal them, and a protective layer 27 provided on this concealing layer 26, the magnetic barcode 23 is As a magnetic material, it is a low coercive force magnetic material that is not detected by a magnet viewer, and
A magnetic material that saturates in an external magnetic field of less than 000 Oe is used, and as the magnetic material of the magnetic barcode 24, a magnetic material with a low coercive force that is not detected by the magnet viewer and that saturates in an external magnetic field of 5000 Oe or more is used. When reading recorded information by passing a DC bias current through the reading magnetic head, the magnitude of the DC bias current I is sequentially increased, and at that time, the DC bias current is The barcodes 23, 24, and 25 are read while the slice level voltage V is sequentially increased in response to I, and recording, information, and authenticity determination are performed based on the different output signal patterns. be.

[0039]Therefore, although conventional magnetic cards could only have one type of output signal pattern, the magnetic card of this embodiment can have at least three types of output signal patterns. This allows magnetic patterns to contain more complex records and information than conventional magnetic barcodes, so when it comes to counterfeiting magnetic cards,
More information can be included in the magnetic pattern than before, and security can be significantly improved. This makes it possible to significantly enhance the anti-counterfeiting effect. In other words, by patterning the output signal and using a reading method and recognition method that utilizes the reproduction output voltage level corresponding to the pattern, it is possible to prevent data tampering or alteration for one or two magnetic recording methods. It has an extremely high anti-counterfeiting effect.

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

In each of the above embodiments, a case has been described in which three types of output signal patterns are obtained by changing the magnitude of the DC bias current and slice level voltage in three stages, but the present invention is not limited to this. It is also possible to obtain a signal pattern.

Further, in each of the above embodiments, the case where a magnetic bar code is provided has been explained, but this is not limited to this, and as long as the bar code has a specific magnetic pattern, an output signal more complicated than the conventional one can be generated using the same method as described above. It is possible to obtain a pattern.

Further, in each of the above embodiments, the case where information is read by sequentially increasing the magnitude of the DC bias current and the slice level voltage has been described; however, the present invention is not limited to this. It is also possible to read information by changing the magnitude of the level voltage so as to sequentially decrease it.

[0044]

Effects of the Invention As explained above, according to the present invention, in a magnetic recording medium in which information is recorded using a magnetic pattern containing a magnetic material, an external magnetic material is used as the magnetic pattern and as a magnetic material when reading information. A magnetic pattern using a magnetic material that is a low coercive force magnetic material that is lower than a magnetic field and saturates in an external magnetic field less than a predetermined value, and a magnetic material that is a low coercive force magnetic material that is lower than an external magnetic field, and the above It consists of a combination with a magnetic pattern using a magnetic material that saturates with an external magnetic field of a predetermined value or more, and when reading recorded information by flowing a DC bias current to the reading magnetic head, the magnitude of the DC bias current is gradually increased. At that time, the slice level voltage is sequentially increased in response to the DC bias current, and the magnetic pattern is read, and the different output signal patterns can be used to record, information, or identify authenticity. A magnetic recording medium that uses a low coercive force magnetic material that is not detected by a magnetic viewer, etc., to provide more information to the fixed information of the magnetic barcode, and can significantly improve the anti-counterfeiting effect. and how to read that information.

[Brief explanation of the drawing]

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

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

FIG. 3 is a characteristic diagram showing an example of the relationship between DC bias current and output voltage value to explain the idea of the present invention.

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

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

[Explanation of symbols]

21... Substrate, 22... Magnetic recording layer, 23, 24... Magnetic barcode, 25... Dummy barcode, 26... Hiding layer, 27
…protective layer.

Claims (3)

[Claims] 1. A magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material, wherein the magnetic material is a low coercivity magnetic material lower than an external magnetic field when reading information. a magnetic pattern using a magnetic material that saturates in an external magnetic field of less than a predetermined value;
A magnetic material characterized by being constructed by combining a magnetic material with a magnetic pattern using a magnetic material having a low coercive force lower than that of an external magnetic field and saturated by an external magnetic field of at least the predetermined value. recoding media. 2. The magnetic recording medium according to claim 1, further comprising a dummy pattern containing no magnetic material. 3. A magnetic pattern using a magnetic material having a low coercive force lower than an external magnetic field and saturated in an external magnetic field less than a predetermined value as a magnetic material; It is a low coercivity magnetic material that is lower than the magnetic field,
A DC bias current is applied to a magnetic head for reading information on a magnetic recording medium in which information is recorded by a magnetic pattern formed by a combination of a magnetic pattern using a magnetic material that is saturated by an external magnetic field of the predetermined value or more. In the reading method, the magnetic pattern is read by sequentially increasing the magnitude of the DC bias current, and at the same time sequentially increasing or decreasing the slice level voltage corresponding to the DC bias current. A method for reading information from a magnetic recording medium, characterized in that recording, information, and authenticity are determined by reading and different output signal patterns.