JPH0535903A - Information reader of magnetic recording medium - Google Patents

Abstract

PURPOSE:To remarkably improve a forgery prevention effect by giving much information by the fixing information of a magnetic bar code for which magnetic material with a low coercive force which is not sensible by a magnet viewer, etc., is used. CONSTITUTION:A magnetic pattern is constituted by combining a magnetic pattern for which magnetic material which is one with a low coercive force lower than at an external magnetic field at the time of reading information as magnetic materials and is saturated at the external magnetic field of less than a prescribed value is used with a magnetic pattern for which magnetic material which is one with a low coercive force lower than at an external magnetic field at the time of reading information as magnetic materials and is saturated at the external magnetic field of more than the prescribed value is used. When recording information is read by flowing direct current bias current to magnetic heads for reading 3, 4, by changing the size of the bias current by sucessively increasing/decreasing it, reading the magnetic pattern by successively increasing/decreasing slice level voltage corresponding to it, performing the truth decision of a magnetic recording medium is executed by the different output signal patterns.

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, in which information is recorded by a magnetic pattern, and in particular, a magnetic pattern The present invention relates to an information reading device for a magnetic recording medium, which is capable of significantly increasing the forgery prevention effect by giving more information to fixed information.

[0002]

2. Description of the Related Art In recent years, in our social life, magnetic cards, magnetic tickets, magnetic commuter passes, magnetic coupons, magnetic sheets.
Magnetic recording media such as G.T. Of these, for example, in a magnetic card, a magnetic recording layer having a thickness of about 10 to 15 μm is usually applied on a non-magnetic substrate having a thickness of 100 to 250 μm. A magnetic bar code which is a magnetic pattern, a concealing layer, a heat-sensitive printing layer, and the like are laminated between the magnetic recording layer and the protective layer which is the top coat. In this case, the number of layers and the types of layers are set according to the required output and required characteristics of the magnetic card.

Among them, the magnetic bar code is a combination of a magnetic bar code containing a magnetic substance and a dummy bar code not containing a magnetic substance, whereby fixed information (for example, amount of money or issuing agency) is recorded on the card. Pattern information), that is, security is added.

FIG. 5 is a sectional view showing a structural example of this type of magnetic card. That is, in the magnetic card, as shown in FIG. 5, after the magnetic recording layer 52 is formed on the base 51,
A magnetic bar code 53 containing magnetic powder having a coercive force lower than that of the magnetic material used for the magnetic recording layer 52 is provided by a method such as offset printing or screen printing, and a dummy bar code 54 is also provided like the magnetic bar code 53. Method. Further, in a normal card, the concealing layer 5 is formed on this.
5. The protective layer 56 is formed by the same method as the magnetic bar code 53.

By the way, in this type of magnetic card,
As the magnetic bar code 53, two types have been conventionally used, and the reading method also differs depending on the type. One of them is that the magnetic barcode 53 is formed using a magnetic material having a coercive force that does not affect the magnetic recording layer 52 and that recording can be sufficiently performed, and is used for the magnetic recording layer 52. It is a method of writing / reading a record by the same method. Examples of magnetic materials used in this case include magnetite (Fe ₃ O ₄ ) and γ-iron oxide (γ-Fe ₂ O ₃ ).

However, the magnetically recorded magnetic bar code 53 used in this method can be distinguished from the magnetic bar code 53 and the dummy bar code 54 by applying a commercially available magnet viewer or the like. In order to prevent this, it is necessary to demagnetize after reading the information recorded in the magnetic bar code 53, which causes a problem that the magnetic bar code reading system becomes complicated and large. .

Therefore, in order to solve such a problem, for example, as shown in "Japanese Patent Laid-Open No. 1-109524",
There is a magnetic bar code using a magnetic material having a coercive force that is not used in magnetic recording, and a magnetic material that is not detected by a magnet viewer having a low coercive force.

This is the second one, and uses carbonyl iron powder, Mn-Zn ferrite, or the like, which is a magnetic material having a low coercive force of 30 Oe or less, which is not detected by the magnet viewer. The method of reading a magnetic barcode formed using these magnetic materials is as follows.
That is, a DC bias current is passed through the reading magnetic head to apply a weak DC bias magnetic field to the magnetic bar code portion to the extent that magnetic recording is not affected. Then, the magnetic bar code having a low coercive force is magnetized by the DC bias magnetic field, and when this is simultaneously read by the reading magnetic head, an output signal waveform as shown in FIG. 6 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, a combination of magnetic bar codes having different coercive forces is added to provide security (see, for example, "JP-A-63-133321").
No. "or" JP-A-63-308724 "), a combination of magnetic bar codes having different magnetization amounts (for example," JP-A-63-223892 "), and a magnetic material using magnetic materials having different Curie points. Various types have been proposed, such as a combination of bar codes (for example, “Jitsukai Sho 62-147191”), all of which are different from fixed magnetic recording in a normal magnetic recording layer. It is information, and in general, providing a magnetic barcode on a magnetic card is nothing but providing security.

However, the conventional bar code is a very simple one which only judges whether or not the bar code using the magnetic material and the bar code using the magnetic material are not present. It cannot be said that it is so effective as a prevention system.

[0011]

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

The present invention has been made to solve the above-mentioned problems, and more information is given to fixed information of a magnetic pattern using a magnetic material having a low coercive force which is not detected by a magnet viewer or the like. An object of the present invention is to provide an information reading device for a magnetic recording medium capable of significantly enhancing the forgery prevention effect.

[0013]

In order to achieve the above object, in the present invention, the magnetic material is a magnetic material having a low coercive force lower than the external magnetic field at the time of reading information, and an external magnetic field less than a predetermined value. A magnetic pattern using a magnetic material that saturates, and a magnetic pattern using a magnetic material that has a low coercive force lower than the external magnetic field at the time of reading information and that saturates in an external magnetic field of a predetermined value or more. In a device for reading information on a magnetic recording medium on which information is recorded by a magnetic pattern composed of a combination of the above, a first bias means for setting a first DC bias current of a predetermined magnitude, and a first bias means.
Second bias means for setting a second DC bias current having a magnitude different from that of the DC bias current and the first DC bias current set by the first bias means to read the magnetic pattern of the magnetic recording medium. A first magnetic head for reading and a second magnetic head set by a second bias means.
The second read magnetic head for reading the magnetic pattern of the magnetic recording medium with the DC bias current and the output signals from each of the first and second read magnetic heads at a predetermined slice level voltage corresponding to the DC bias current. Slice level means for slicing, first binarizing means and second binarizing means for converting output signals from the first and second read magnetic heads sliced by the slice level means into binary data, respectively. Means and the output data from the first binarizing means and the output data from the second binarizing means are compared and collated, and the comparison collated data is code-decoded to determine the authenticity of the magnetic recording medium. It is provided with an authenticity determining means for performing.

Here, especially as the authenticity determination means, the first
An inversion circuit that inverts the output data from the binarizing means, a logical product circuit that takes a logical product (AND) condition between the output data from the inverting circuit and the output data from the second binarizing means, and Based on a clock signal obtained from the pattern information, a register circuit for sampling the output data from the AND circuit, and a decoder for decoding the data sampled by the register circuit to determine the authenticity of the magnetic recording medium. Made of

[0015]

Therefore, in the information reading apparatus for the magnetic recording medium of the present invention, the magnetic material is a magnetic material having a low coercive force lower than the external magnetic field at the time of reading the information, and the magnetic material is saturated in the external magnetic field less than the predetermined value. From a combination of a magnetic pattern using the body and a magnetic material using a magnetic material that has a low coercive force lower than the external magnetic field at the time of reading information and that is saturated with the external magnetic field of a predetermined value or more A magnetic pattern is formed, and DC bias currents of different magnitudes are respectively applied to the first and second read magnetic heads to read the magnetic pattern of the magnetic recording medium, and the first and second read magnetic heads are read. The output signal from the magnetic head is sliced at a predetermined slice level voltage, each sliced output signal is converted into binary data, and each binary data is compared. Collating, and by performing authenticity determination of the magnetic recording medium encoding decrypt the comparison and collation data, it is possible to obtain at least two or more different output signal patterns.

This allows the magnetic pattern to have more complicated recording and information than the conventional magnetic pattern. Therefore, when it comes to forgery of a magnetic recording medium, more information can be included in the magnetic pattern than before. Therefore, the security can be significantly improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a magnetic pattern in a magnetic recording medium in which information is recorded by a magnetic pattern containing a magnetic material, and as a magnetic material, a low coercive force magnetic material lower than an external magnetic field at the time of reading information. And a magnetic pattern using a magnetic material that is saturated with an external magnetic field less than a predetermined value, and a low coercive force magnetic material lower than the external magnetic field at the time of reading information as a magnetic material, It is configured by a combination with a magnetic pattern using a magnetic substance that is saturated by a magnetic field.

That is, a magnetic pattern using a magnetic material having a low coercive force is read by applying a DC bias current to the reading magnetic head as described above. In this case, for example, from the experimental results shown in FIG. 4, the magnetic patterns using the saturated type magnetic body (A) 11 and the magnetic patterns using the unsaturated type magnetic body (B) 12 flow. It can be seen that the output voltage characteristics differ greatly depending on the magnitude of the DC bias current. That is, in the saturated type magnetic body (A) 11, the output voltage value shows a larger value than the unsaturated type magnetic body (B) 12 with a small DC bias current, and is saturated. On the other hand, the output voltage value of the unsaturated type magnetic body (B) 12 increases linearly in the DC bias current in a range that does not affect the magnetic recording layer which is the base of the magnetic pattern. Therefore, if such a property is utilized, when a magnetic pattern is read with different DC bias currents, it is composed of a combination of a dummy, a saturated type magnetic body (A) 11 and an unsaturated type magnetic body (B) 12. At least two types of information can be read by the magnetic pattern.

In the present invention, for example, DC bias current values I ₁ and I ₂ (I ₁ <I ₂ ) and slice levels V ₁ and V ₂ (V ₁ <V ₂ ) of output voltage values as shown in FIG. 4 are used. Are set respectively. Here, when the magnetic pattern is read with the combination of (I ₁ , V ₁ ), only the magnetic pattern using the saturation type magnetic body (A) 11 is obtained as the output signal. With the combination of (I ₂ , V ₂ ), both magnetic patterns using the saturated type magnetic body (A) 11 and the unsaturated type magnetic body (B) 12 are read.

As described above, at least two or more different output signals are obtained in the magnetic pattern in which only one type of pattern output signal was conventionally obtained by forming the magnetic pattern with the above-described structure and reading the information. You can get the pattern.

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

FIG. 2 is a sectional view showing a structural example of a magnetic card applied to the present invention. The magnetic card of this embodiment is
As shown in FIG. 2, a base material 21, a magnetic recording layer 22 provided on the base material 21, a plurality of magnetic bar codes 23 that are magnetic patterns provided on the magnetic recording layer 22,
24 and the dummy bar code 25, and the concealment layer 26 provided on the magnetic bar codes 23 and 24, the dummy bar code 25 and the magnetic recording layer 22 to conceal them.
It is composed of a protective layer 27 provided on the concealing layer 26. The number of layers, the type of layers, the layer thickness, etc. are usually set according to the required output and required 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, and paper and synthetic paper can be used alone or as a composite. Further, the magnetic recording layer 22 is formed of, for example, a known B
Using magnetic ink prepared by dispersing magnetic fine particles of a-ferrite, Sr-ferrite, γ-iron oxide, etc. in a suitable resin such as polyurethane resin, vinyl chloride-vinyl acetate copolymer, polyester resin, etc. The magnetic ink can be applied by a method such as roll coating, gravure coating, or screen printing, and dried to form. In this case, as the composition of the magnetic ink, the adhesiveness to the base material 21, the flexibility when it becomes a coating film, the abrasion resistance, the chemical resistance, etc. are considered.

On the other hand, the magnetic bar codes 23 and 24 are magnetic inks prepared by dispersing magnetic fine particles in a suitable resin, for example, vinyl chloride-vinyl acetate copolymer, polyester resin or the like, and the dummy bar code 25 is used. Ordinary commercially available ink can be used. in this case,
The magnetic fine particles of the magnetic bar code 23 are magnetic materials having a low coercive force which is not detected by a magnet viewer and which are saturated with an external magnetic field of less than a predetermined value (for example, 5000 Oe), that is, 11 in FIG. 4 described above. A saturated type magnetic material (A) as shown in FIG. Further, the magnetic fine particles of the magnetic bar code 24 are magnetic materials having a low coercive force which is not detected by the magnet viewer and which are saturated with an external magnetic field of a predetermined value (for example, 5000 Oe), that is, for example, as shown in FIG. The unsaturated type magnetic material (B) as shown in No. 12 can be used.

On the other hand, the concealing layer 26 is composed of the magnetic bar code 2
3, 24, dummy barcode 25 and magnetic recording layer 22
Is concealed so that it cannot be visually discerned, and an ink with a high concealing property, for example, Ag, Cr, Al, Zn, S
A non-magnetic metal powder such as n, Pb, Cu, Bi, Ge and In is dispersed in a binder solution to form an ink. Further, the protective layer 27 has a role of protecting the concealing layer 26, and as the material thereof, for example, 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, as 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 30 parts by weight. Part of the composition was applied by gravure coating to a thickness of 15 μm.

On the other hand, as a magnetic ink for the magnetic bar code 23 of the saturated type (A), 70 parts by weight of Mn-Zn ferrite, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin, 10 parts by weight of cyclohexanone, and 10 parts by weight of butyl cellosolve are used. 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.

As the ink for the dummy bar code 25, gray ink manufactured by Seiko Advance Co., Ltd. was used.

Using each of the above bar code inks, 5 pieces (A, A, B, and 5 mm) having a width of 1 mm and a length of 5 mm are used.
The dummy, A) pattern was formed by screen printing using a screen plate 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.

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

After the above printing, the card was pulled out to a prescribed size to manufacture a magnetic card of this example.

Next, FIG. 1 is a block diagram showing a configuration example of an information reading apparatus for a magnetic card according to the present invention.

As shown in FIG. 1, the information reading apparatus of this embodiment comprises a first bias circuit 1, a second bias circuit 2, a first read magnetic head 3, and a second read circuit. The magnetic head 4, the slice level circuit 5, and the first 2
It is composed of a binarizing amplifier circuit 6, a second binarizing amplifier circuit 7, an inverting (NOT) circuit 8, a logical product (AND) circuit 9, a register circuit 10, and a decoder 15. The inverting (NOT) circuit 8 and the logical product (AND) circuit 9
The register circuit 10 and the decoder 115 constitute a true / false determination unit.

Here, the first bias circuit 1 is for setting a first DC bias current of a predetermined magnitude. The second bias circuit 2 sets a second DC bias current having a magnitude different from that of the first DC bias current. Further, the first read magnetic head 3 reads the bar code information of the magnetic card 16 with the first DC bias current set by the first bias circuit 1. Furthermore, the second read magnetic head 4 reads the bar code information of the magnetic card 16 with the second DC bias current set by the second bias circuit 2.

On the other hand, the slice level circuit 5 slices the output signals from the first and second read magnetic heads 1 and 2 with a predetermined slice level voltage corresponding to the DC bias current. The first binarizing amplifier circuit 6 converts the output signal from the first read magnetic head 1 sliced by the slice level circuit 5 into binary data. Further, the second binarizing / amplifying circuit 7 converts the output signal from the second read magnetic head 2 sliced by the slice level circuit 5 into binary data.

On the other hand, the inverting (NOT) circuit 8 has the first 2
The output data from the binarizing and amplifying circuit 6 is inverted. The logical product (AND) circuit 9 takes a logical product (AND) condition of the output data from the inverting circuit 8 and the output data from the second binarizing and amplifying circuit 7. Further, the register circuit 10 samples the output data from the AND circuit 9 based on the clock signal 17 created by operating a reference pulse generator (not shown) based on the bar code information. Furthermore, the decoder 15 decodes the data sampled by the register circuit 10 to determine the authenticity of the magnetic card 16.

Next, the operation in the case of reading the information of the bar code portion of the magnetic card 12 by the information reading apparatus configured as described above will be described with reference to FIG.

As shown in (c) of FIG. 3, the bar code pattern is (A, A, B, dummy, A). The bar code pattern of the magnetic card 16 is read by the first read magnetic head 3 set to I ₁ = 10 mA by the first bias circuit 1. The output signal waveform in this case is as shown in FIG. The output signal from the first read magnetic head 3 is a slice level voltage set to V ₁ = 0.6V by the slice level circuit 5, and is an unsaturated type magnetic material (B) 12 in the bar code pattern. Magnetic barcode 2
The output from 4 is sliced. The signal sliced by the slice level circuit 5 is digitally converted into binary data by the first binarizing amplifier circuit 6, and the magnetic field using the saturation type magnetic material (A) 11 in the bar code pattern is used. A signal of "1" is obtained only for the output from the bar code 23. That is, (A,
From the bar code of the pattern of A, B, dummy, A),
The data of (1,1,0,0,1) is detected. Further, this (1, 1, 0, 0, 1) data is inverted (N
The data (0, 0, 1, 1, 0) inverted by the (OT) circuit 8 is input to the logical product (AND) circuit 9.

On the other hand, for the same magnetic card 16, the magnitude of the DC bias current is I _{1 in the} second bias circuit 2.
The bar code pattern of the magnetic card 16 is read by the second read magnetic head 4 set to = 40 mA. The output signal waveform in this case is as shown in FIG. The output signal from the second read magnetic head 4 is V ₁ = in the slice level circuit 5.
Slice with the slice level voltage set to 1.0V. Then, the signal sliced by the slice level circuit 5 is digitally converted into binary data by the second binarization amplifier circuit 7, and the magnetic field using the saturation type magnetic material (A) 11 in the bar code pattern is used. A signal of "1" is obtained for the outputs from both the bar code 23 and the magnetic bar code 24 using the unsaturated type magnetic material (B) 12. That is, the data of (1, 1, 1, 0, 1) is detected from the barcode of the pattern of (A, A, B, dummy, A). Further, the data of (1, 1, 1, 0, 1) is input to the logical product (AND) circuit 9.

As a result, in the logical product (AND) circuit 9, the logical product (AND) condition of the output data from the inverting circuit 8 and the output data from the second binarizing and amplifying circuit 7 is taken. Data of the result (0, 0, 1, 0, 0) is obtained and is input to the register circuit 10. That is,
In this embodiment, the unsaturated type magnetic material (B) 12 is read with the saturated type magnetic material (A) 11 as a reference.

On the other hand, the register circuit 10 receives a clock signal 17 created by operating a reference pulse generator (not shown) based on the bar code information, and based on the clock signal 17, the AND circuit 9 outputs the clock signal 17. The output data (0,0,1,0,0) is sampled. Further, in the decoder 15, the sampled data (0,0,1,0,0) is code-decoded, and the authenticity of the magnetic card 16 input to the information reading apparatus is judged. As a result, when the magnetic card 16 is “true”, the following processing (reading of the magnetic recording layer 22)
If the magnetic card 16 is “fake”, the process for ejecting the magnetic card 16 input to the information reading device or an alarm such as a buzzer sound indicating that the magnetic card 16 is abnormal is issued. Processing will be performed.

Therefore, the bar code can be read as described above, and recording, information, and authenticity determination can be performed by the different output signal patterns. That is,
Due to the difference in the output voltage levels, the legitimacy of the magnetic card can be known by setting the reading method and the recognition method corresponding to the pattern in advance as shown in FIG. If the output voltage level difference does not occur, it is not the 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 recording layer 22, and a magnetic card including a concealing layer 26 for concealing these and a protective layer 27 provided on the concealing layer 26. As a magnetic material, a low coercive force magnetic material that is not detected by a magnet viewer, and
A magnetic substance 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 substance that has a low coercive force that is not detected by a magnet viewer and that saturates in an external magnetic field of 5000 Oe or more is used. A magnetic bar code is constructed by using the first bias circuit 1 for setting a first direct current bias current having a predetermined magnitude and a second device having a magnitude different from the first direct current bias current. Second bias circuit 2 for setting the DC bias current of the first read magnetic head 3 for reading the bar code information of the magnetic card 16 with the first DC bias current set by the first bias circuit 1. And a second read magnetic field for reading the bar code information of the magnetic card 16 with the second DC bias current set by the second bias circuit 2. And de 4, a slice level circuit 5 for slicing in the first and the second output signal from the magnetic head 1 and 2 for each reading of a predetermined slice level voltage corresponding to the DC bias current, the slice level circuit 5
The first read / write magnetic head 2 sliced by the slice level circuit 5 and the first binarization amplifier circuit 6 for converting the output signal from the first read magnetic head 1 sliced by Second binarization amplifier circuit 7 for converting the output signal from the first binarization data into binary data, and inversion (NOT) for inverting the output data from the first binarization amplifier circuit 6.
Based on the circuit 8, the logical product (AND) circuit 9 which takes a logical product (AND) condition of the output data from the inverting circuit 8 and the output data from the second binarization amplification circuit 7, and the bar code information. A register circuit 10 for sampling the output data from the AND circuit 9 and the data sampled by the register circuit 10 are code-decoded based on the clock signal 17 created by It is composed of a decoder 15.

Therefore, the bar code 23, while changing the magnitude of the DC bias current I so as to sequentially increase and further increasing the slice level voltage V correspondingly to the DC bias current I at that time. Two
4, 25 are read, and recording, information, and authenticity determination can be performed by different output signal patterns. That is, conventionally, only one type of output signal pattern can be provided, but the magnetic card 12 of the present embodiment can have at least three types of output signal patterns. As a result, more complicated recording and information than the conventional magnetic bar code can be given to the magnetic pattern, so when it comes to forgery of a magnetic card, more information can be included in the magnetic pattern than before. It is possible to significantly improve security.
This makes it possible to remarkably enhance the forgery prevention effect. In other words, by patterning the output signal, by using the reading method and the recognition method that utilize the reproduction output voltage level corresponding to the pattern, the data can be tampered with or altered with respect to one or two magnetic recording methods. In contrast, the anti-counterfeiting effect is extremely high.

The present invention is not limited to the above-mentioned embodiments, but can be implemented in the same manner as described below.

In each of the above embodiments, the case where the magnitudes of the DC bias current and the slice level voltage are changed in three steps to obtain three types of output signal patterns has been described, but the present invention is not limited to this, and four or more types of output are provided. It is also possible to obtain a signal pattern.

Further, in the above embodiment, the case where the magnetic bar code is provided has been described, but the present invention is not limited to this, and as long as it has a specific magnetic pattern, an output signal pattern more complicated than the conventional one can be obtained by the same method as described above. Is what you can get.

Further, in the above embodiment, the case where the magnitude of the DC bias current and the slice level voltage is changed so as to be sequentially increased and the information is read is described, but the present invention is not limited to this, and the DC bias current and the slice level voltage are read. It is also possible to read the information by changing the magnitude of the voltage so as to be gradually decreased.

Furthermore, in the above-described embodiment, the case where the unsaturated type magnetic body (B) 12 is read with the saturated type magnetic body (A) 11 as a reference has been described. Saturation type magnetic body (B) 1
Saturation type magnetic material (A) 1 with reference to 2
It is also possible to read 1. In this case,
The inversion (NOT) circuit 8 is replaced with the second binarization amplifier circuit 7
It may be provided in the output stage of.

[0053]

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, the magnetic material is lower than the external magnetic field at the time of reading information. A magnetic pattern using a magnetic material that is a low coercive force magnetic substance and is saturated with an external magnetic field less than a predetermined value, and a magnetic material that is a low coercive force magnetic substance lower than the external magnetic field at the time of reading information, and A first bias means configured to be combined with a magnetic pattern using a magnetic substance that is saturated with an external magnetic field of a predetermined value or more, and further, a first bias means for setting a first direct current bias current of a predetermined magnitude; and a first direct current bias. A second bias means for setting a second DC bias current having a magnitude different from the current, and a magnetic pattern of the magnetic recording medium with the first DC bias current set by the first bias means. A first read magnetic head for reading, a second read magnetic head for reading a magnetic pattern of a magnetic recording medium with a second DC bias current set by a second bias means, and a first read magnetic head. Of the output signals from the first and second read magnetic heads sliced by the slice level means, and the slice level means for slicing the output signal from the slice level means with a predetermined slice level voltage corresponding to the DC bias current. First binarizing means and second second
The binarizing means, the output data from the first binarizing means, and the second
Since it is configured to include a genuine / counterfeit determining unit that compares and collates the output data from the binarizing unit and decodes the comparative collating data to determine whether the magnetic recording medium is true or false, the magnet. It is possible to provide an information reading device for a magnetic recording medium, which can give more information to the fixed information of the magnetic bar code using a magnetic material having a low coercive force that is not sensed by a viewer or the like and can remarkably enhance the forgery prevention effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an information reading device for a magnetic card according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of a magnetic card applied to the present invention.

FIG. 3 is a waveform chart showing an example of an output signal pattern of a magnetic barcode in the example.

FIG. 4 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. 5 is a cross-sectional view showing a configuration example of a conventional magnetic card.

FIG. 6 is a waveform diagram showing an example of an output signal pattern of a conventional magnetic bar code.

[Explanation of symbols]

1 ... 1st bias circuit, 2 ... 2nd bias circuit, 3
... first read magnetic head, 4 ... second read magnetic head, 5 ... slice level circuit, 6 ... first binarization amplifier circuit, 7 ... second binarization amplifier circuit, 8 ... inversion (NO
T) circuit, 9 ... AND circuit, 10 ... Register circuit, 15 ... Decoder, 16 ... Magnetic card, 17 ... Clock signal, 21 ... Substrate, 22 ... Magnetic recording layer, 23, 24
... magnetic bar code, 25 ... dummy bar code, 26 ... concealing layer, 27 ... protective layer.

Claims (2)

[Claims] 1. A magnetic pattern that uses a magnetic material having a low coercive force lower than an external magnetic field at the time of reading information as a magnetic material and that is saturated with an external magnetic field less than a predetermined value, and an information as the magnetic material. A magnetic material having a low coercive force lower than the external magnetic field at the time of reading and a magnetic pattern in which information is recorded in combination with a magnetic pattern using a magnetic material that is saturated by the external magnetic field having a predetermined value or more. In an apparatus for reading information on a recording medium, a first direct current bias current of a predetermined magnitude is set.
Bias means for setting a second DC bias current having a magnitude different from that of the first DC bias current, and a first DC bias current set by the first bias means. A first read magnetic head for reading the magnetic pattern of the magnetic recording medium, and a second read magnetic head for reading the magnetic pattern of the magnetic recording medium with a second DC bias current set by the second bias means. Slice level means for slicing the output signals from the magnetic head and the first and second read magnetic heads at a predetermined slice level voltage corresponding to the DC bias current, and sliced by the slice level means. The first
And first binarizing means for converting the output signals from the second reading magnetic head into binary data, and the second binarizing means.
Binarizing means, output data from the first binarizing means, and the second binary data.
Magnetic recording comprising: authenticity determining means for comparing and collating output data from the digitizing means, and decoding the comparative collating data to determine the authenticity of the magnetic recording medium. Media information reader. 2. The authenticity determining means includes an inverting circuit that inverts output data from the first binarizing means,
Based on a logical product circuit that takes a logical product (AND) condition of output data from the inverting circuit and output data from the second binarizing means, and a clock signal obtained from the magnetic pattern information, 2. A register circuit for sampling the output data from the logical product circuit, and a decoder for decoding the data sampled by the register circuit to determine the authenticity of the magnetic recording medium. An information reading apparatus for the magnetic recording medium described.