JPH06325344A - Magnetic recording medium and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a magnetic recording medium having high productivity and hard to counterfeit, such as a magnetic card such as a shopping card, a commuter pass, a ticket, a magnetic sheet, and a magnetic roll paper, and a manufacturing method thereof. A method for preventing forgery of a magnetic recording medium is provided. [Structure] 200 to 50 is formed on a base made of a non-magnetic material.
A magnetic recording layer made of a magnetic material having a coercive force of 00 oersted and a magnetic thin film layer having a coercive force of 1000 oersted or less are sequentially laminated, and fixed information that cannot be added or erased later is formed on the magnetic thin film layer. Recording medium and manufacturing method thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to magnetic cards such as shopping cards, savings and savings cards, commuter passes, boarding tickets, coupons, pre-baid cards, cash cards, credit cards, identification cards, medical examination cards, magnetic sheets, magnetic rolls. The present invention relates to a magnetic recording medium used for paper and the like and a manufacturing method thereof.

[0002]

2. Description of the Related Art Recently, the fields of application of magnetic recording media such as magnetic recording cards or magnetic roll paper are becoming wider. The basic structure is that a magnetic layer is provided on a non-magnetic substrate and magnetized. In such a magnetic recording medium, it is necessary to prevent illegal use due to duplication or falsification of magnetic information, and therefore various illegal use prevention measures are taken. Typical methods for preventing unauthorized use are roughly classified into a method of making it difficult to record and reproduce magnetic recording information and a method of providing the magnetic recording medium itself with authenticity determination information. The former is a method of hiding recorded magnetic information and making it difficult to falsify or copy the magnetic information by making it difficult to write or read the information.
The latter is a method of preventing forgery and alteration by putting identification information for determining whether or not the magnetic card is legitimate into the card itself.

[0003]

More specifically, the former known measure for preventing unauthorized use by making it difficult to record and reproduce magnetically recorded information has a multilayer magnetic recording layer. This makes it impossible to read the legitimate information by making it unreadable or superimposing dummy information to make it difficult to analyze the legitimate information.However, if the legitimate information and the dummy information are recorded on the same track, the Since the dummy information is sometimes superimposed on the legitimate information, the legitimate information cannot be read by a normal method. However, there are drawbacks such as a complicated writing and reading device for recording,
Also, once the details of the method for reading legitimate information are known, if you are familiar with magnetic recording, you can read the information,
Since it can be analyzed, there is a problem that a large number of magnetic recording media can be duplicated. On the other hand, in the latter magnetic card itself, which is provided with authenticity determination information, for example, a magnetic recording medium is provided with a magnetically readable bar code, and the authenticity of the information is determined by the bar code information. It is difficult to illegally use by duplicating a large amount of medium because the medium itself has the information to judge whether the magnetic recording medium is legitimate, but illegal use such as rewriting the information on the legitimate medium. Can not deal with.

[0004]

The magnetic recording medium according to the present invention is provided with the latter function of preventing unauthorized use, but unlike the conventional magnetic recording medium, different fingerprint information is given to each medium. Illegal use is impossible because
At the same time, the layer formed for imparting the fraud prevention function can also be used as a print recording layer, which is convenient.

The outline of the present invention is as follows. The invention according to claim 1 is characterized in that 20
A magnetic layer made of a magnetic material having a coercive force of 0 Oersted to 5000 Oersted and a magnetic thin film layer having a coercive force of 1000 Oersted or less are sequentially laminated, and fixed information that cannot be added or erased later is formed on the magnetic thin film layer. It is a magnetic recording medium characterized in that According to the invention of claim 2, in manufacturing the magnetic recording medium according to claim 1, a magnetic coating material having a coercive force of 200 Oersted to 5000 Oersted is applied on a substrate made of a non-magnetic material and dried to form a magnetic recording layer. Then, the method for producing a magnetic recording medium is characterized in that a magnetic thin film layer is formed on the magnetic recording layer by at least one method selected from a vapor deposition method, a sputtering method and a plating method. The invention of claim 3 is claim 1
A magnetic recording medium is characterized in that the magnetic thin film layer of the magnetic recording medium described above is printed by a discharge breakdown method.

In the method of manufacturing the magnetic recording medium according to the second aspect, magnetic recording is first performed on the magnetic recording layer formed on the non-magnetic material, and then the magnetic thin film layer is formed thereon. The magnetic metal, magnetic alloy, or magnetic compound forming the magnetic thin film layer is deposited thicker than other portions on the magnetic flux reversal interface portion of the magnetic recording layer to form a pattern. This pattern portion has the same function as a magnetic bar code made of a magnetic metal, a magnetic alloy or a magnetic compound, and can be magnetically detected by a magnetic head or the like. That is, this pattern becomes fixed information that cannot be added or erased later, and can be used as information for preventing unauthorized use of the medium.

In the present invention, the content of the fixed information formed on the non-magnetic thin film is determined by the magnetic recording information on the magnetic recording layer. That is, by controlling the magnetic recording information, it becomes possible to give different fixed information to each magnetic card in the final product magnetic recording medium, for example.

Conventionally, since such fixed information is formed by a printing method, it is only possible to give the same information or only a limited kind of information to each magnetic recording medium. On the other hand, according to the method of the present invention, it is possible to dramatically increase the recording density of fixed information, and it is possible to add more complicated information.

It is preferable that the magnetic information formed in a pattern is difficult to visually confirm because it is used as illegal use prevention information. According to the method of the present invention, it is possible to obtain a sufficient magnetic output even if the fixed information formed in the pattern is very thin, and the physical protrusion (thickness) of the pattern may be small. , It is difficult to visually confirm, and it is easy to hide. Further, in the method of the present invention, the layer formed on the magnetic recording layer is a magnetic thin film layer, which is very thin, so that it has almost no adverse effect on ordinary magnetic recording performed on a portion other than the fixed information portion. It has the characteristic that it does not exist. In addition to the function that the magnetic thin film layer has fixed information for preventing forgery formed, the magnetic thin film layer also has the function of a print recording layer by the discharge printing method. It is possible to perform print recording requiring visual inspection.

The present invention will be described below with reference to the drawings.
FIG. 1A is a plan view of a magnetic recording medium (card) according to the present invention, which has a magnetic track T. FIG. 1B is a sectional view taken along the line XX 'of the track T. The magnetic recording layer 2 made of a magnetic material having a coercive force of 200 Oersted to 5000 Oersted and the adhesion auxiliary layer 3 are formed on a substrate 1 made of a non-magnetic layer. 10,
It is composed of a magnetic thin film layer 4 of not more than 00 Oersted and a protective layer 5 provided as necessary. A portion T in FIG. 1A is a track of magnetic recording performed on the magnetic recording layer.
P corresponds to the magnetic flux reversal interface portion of the magnetic recording performed on the magnetic recording layer, and the magnetic thin film layer formed on the magnetic recording layer is thickly deposited on this portion, so that fixed information in a pattern is formed. Further, the protective layer 5 may be further printed with a graphic character or the like and a protective coating.

Next, materials constituting the magnetic recording medium of the present invention will be described. First of all, as the base made of non-magnetic material,
A sheet-shaped non-magnetic material such as a polyester film having a thickness of 150 μm to 1 mm, a vinyl chloride film, a synthetic paper, a wood pulp paper, a laminated paper, a metal sheet, or a ceramic such as glass can be applied. The magnetic substance used for the magnetic recording layer laminated adjacent to the substrate is not particularly limited, but is generally a ferromagnetic substance having a coercive force of 200 to 5000 oersted, for example, γ-iron oxide, cobalt-doped γ. −
Fine powders of iron oxide, chromium oxide, barium ferrite, strontium ferrite, etc. are applied. These magnetic materials are used as binders for vinyl chloride / vinyl acetate copolymers, vinyl chloride / vinyl acetate / vinyl alcohol copolymers, polyurethane resins, polyester resins, epoxy resins, polyisocyanate resins, and other additives such as pigments. A magnetic recording layer can be formed by dispersing and forming a coating liquid or ink together with the coating liquid or printing on a substrate.
At this time, the magnetic recording layer 2 may be subjected to a magnetic field orientation treatment before the magnetic paint or ink is dried.

The magnetic thin film layer 4 is provided to form fixed information, to function as a forgery prevention function, and to function as a print recording layer by a discharge printing method. As a material for forming the magnetic thin film layer, it is necessary that the coercive force is 1000 oersted or less. For example, a magnetic metal such as Ni, Co or Fe, a sendust alloy which is an Fe-Al-Si based alloy,
Fe-Al based alloys, Fe-Si based alloys, Fe-Ni based permalloys, Ni-Fe-Mo based supermalloys and other alloys, transition metals and transition metal-metalloid amorphous alloys, magnetic properties such as gamma iron oxide and barium ferrite. Soft magnetic ferrites such as metal compounds, Zn ferrite, and Mn.Zn ferrite are applied to the present invention. The magnetic thin film layer is formed by using these materials by vapor deposition, sputtering or plating. If the coercive force is 1000 oersteds or more, it becomes difficult to concentrate and deposit the material forming the magnetic thin film layer on the magnetic flux reversal interface portion of the magnetic recording performed on the magnetic recording layer, and it becomes difficult to form the fixed information. .

In the magnetic recording medium of the present invention, it is preferable to provide an adhesion auxiliary layer 3 between the magnetic recording layer 2 and the magnetic thin film layer 4. The adhesion auxiliary layer 3 is provided between the magnetic recording layer and the magnetic thin film layer to improve the adhesive force between them, and also has the function of promoting the destruction of the magnetic thin film layer 4 during discharge recording and improving the print recording characteristics. have. Examples of the material include acrylic resin such as polystyrene and polymethylmethacrylate (PMMA), cellulose acetate propionate (C
Cellulose resins such as AP), thermoplastic resins such as vinyl chloride-vinyl acetate copolymer resins, polyester resins, epoxy resins and urethane resins are used. Further, in order to control the thermoplasticity of the thermoplastic resin, additives such as a plasticizer, wax and inorganic pigment may be added to the adhesion auxiliary layer. When the magnetic thin film layer is not used as the discharge print recording layer, a thermosetting resin, such as a polyester resin, a polyisocyanate curing agent and a two-liquid mixed type resin, may be used for the adhesion auxiliary layer. Further, it is also possible to use a photocurable resin, an electron beam curable resin or the like made of an acrylic oligomer. If the magnetic recording layer and the magnetic thin film layer are sufficiently adhered, the adhesion auxiliary layer may not be provided. Further, as the protective layer 5 which is provided if necessary, a resin such as a cellulose-based resin, a polyester-based resin, a urethane-based resin, an epoxy-based resin, or an acrylic resin can be used. These resins may be used alone or in combination of two or more, or may be used in combination with a curing agent such as an isocyanate curing agent. Also acrylic,
An ultraviolet curable resin or an electron beam curable resin made of polyester, epoxy, phosphazene or the like resin may be used. Wax, an inorganic pigment, a silicon-based compound, or a fluorine-based compound may be added to these resin systems individually or in combination in order to enhance discharge recording characteristics.

The manufacturing method of the present invention will be described in more detail. For example, as shown in FIG. 2, a substrate 1 made of a non-magnetic material is delivered from a delivery reel 11 and guided to a coating device 12 for coating a magnetic recording layer. To apply. Coating head 1
The substrate 1 applied in 3 is wound on a winding reel 18 via a roll 14, a magnetic field orientation device 15, a drying part 16 and a roll 17. The wound roll is a raw material coated with only the magnetic recording layer. Next, an adhesion auxiliary layer is applied to the surface of the magnetic recording layer. The coating method is the same as that of the above-mentioned magnetic recording layer. At this time, a recording magnetic head is mounted at position 19 of the coating device to perform magnetic recording on the magnetic recording layer. Recording may be performed in the same manner as recording on a magnetic recording medium using an ordinary magnetic recording device. If the adhesion between the magnetic recording layer and the magnetic thin film layer is sufficient, it is not necessary to provide the adhesion auxiliary layer, but in this case, magnetic recording may be performed using a magnetic recording device as shown in FIG. 3, for example. In any case, the situation of magnetic recording will be described as shown in FIGS. That is, the magnetic original sheet 22 having the magnetic recording layer 2 is sent out from the magnetic original sheet roll 23, magnetized by the magnetic head 21 composed of electromagnets connected to a plurality of drive circuits (not shown), and fixed for forgery prevention. The magnetic information that is the source of the information is recorded. Reference numeral 25 is a magnetic recording track, and the magnetic material 22 is wound around a magnetically recorded material material roll 24. The same reference numerals in each figure indicate the same parts. On the magnetic recording track 25, a magnetic flux reversal interface portion 31 is formed in the magnetic recording portion 26 as shown in a sectional view of FIG. Then, a magnetic thin film layer is formed on the magnetic recording layer on which magnetic recording has been performed, with or without an adhesion auxiliary layer. The magnetic thin film layer is formed by a vapor deposition method, a sputtering method, a plating method, or the like. Then, as shown in FIG. 6, the material forming the magnetic thin film layer is thickly deposited on the magnetic flux reversal interface 31 to form the fixed information pattern 32.

In the above method, the magnetic substance mixed in the magnetic recording layer has a coercive force of 200 Oersted to 5000 Oersteds, which is about the same as that of a normal magnetic recording medium.
After forming the magnetic recording layer, magnetic recording can be easily performed with a magnetic recording head. In this case, if the magnetic substance is less than 250 Oersted, the magnetic recording external magnetic field causes the problem of being erased, while if it exceeds 5,000 Oersted, the magnetic recording of the magnetic head currently in practical use becomes impossible. When forming the magnetic thin film layer 4, first, magnetic recording is performed on the magnetic recording layer previously formed. Recording may be performed at a predetermined recording density by using a recording magnetic head, as in ordinary magnetic recording. As an example, magnetic recording is performed as follows. The digital FM recording method is used to apply a pulse current to the recording magnetic head, which enables sufficient saturated recording on the magnetic recording layer. As the record information, it is sufficient to record the information that each recording medium (for example, one magnetic card) as a final product should have. That is, different recording media may be recorded on different recording media, such as uniform number information or random fingerprint information, or recognition information for each manufacturing lot,
Unified information such as manufacturer code may be used. Also, these may be combined.

As described above, the magnetic thin film layer 4 is formed by using the sputtering method, the vapor deposition method or the plating method. The material forming the magnetic thin film layer is concentrated and deposited on the portion of the magnetic field reversal interface where the magnetic field is strong in the magnetic recording pattern previously formed on the magnetic recording layer, and a pattern corresponding to the magnetic recording pattern is formed on the magnetic thin film layer. It is fixed. The pattern formed on the magnetic thin film layer can be magnetically read even after the magnetic recording information provided on the magnetic recording layer is erased. For example, by reading with a magnetic head while applying a DC bias magnetic field, an output according to the pattern can be obtained.
If the coercive force of the magnetic thin film layer is 20 Oersted or less,
Even after reading fixed information with a magnetic head while applying a bias magnetic field, the pattern part does not become magnetized,
Since the presence of the pattern cannot be confirmed by observation with a magnetic viewer or the like, it is more preferable for use in preventing unauthorized use.

The fixed pattern information formed on the magnetic thin film layer is formed corresponding to the magnetic recording information formed on the magnetic recording layer. Therefore, when the fixed information is changed, the magnetic recording information performed on the magnetic recording layer may be changed in the manufacturing process, which can be easily changed. When fixed information such as a magnetic barcode is formed by using a printing method or the like, a new plate must be created each time the fixed information is changed, but this method is not necessary.

[0018]

EXAMPLES The present invention will be described in detail below based on examples. In addition, all parts represented by the material composition are parts by weight. After the mixture prepared by the following composition was dispersed by a ball mill for 8 hours, 5 parts of a polyisocyanate curing agent was added,
Further, the dispersion was carried out for 1 hour to obtain a coating material for the magnetic recording layer. The coating material was applied by a reverse roll coater to one side of a substrate made of a white polyester film having a thickness of 188 μm so that the coating thickness after drying was 12 μm, to form a magnetic recording layer. At this time, the magnetic recording layer was subjected to a magnetic field orientation treatment by a magnetic field orientation device before being dried. Barium ferrite (coercive force 2750 oersted, specific surface area 7 m ² / g) 100 parts Carbon black 3 parts Lecithin 1 part Vinyl chloride / vinyl acetate / vinyl alcohol copolymer 20 parts Polyurethane resin 20 parts Toluene 60 parts Methyl ethyl ketone 60 parts Methyl isobutyl ketone 60 copies

Magnetic recording was performed on the magnetic recording layer thus obtained using a magnetic head. A magnetic head having a head gap of 50 μm was used, and recording was performed at a recording current that was sufficient for saturated recording on the magnetic recording layer. The recording method was the FM method and the recording density was 250 bpi.
Then, the surface of the magnetic recording layer was coated with a coating material for an adhesion auxiliary layer having the following composition by a reverse roll coater so that the coating thickness after drying was 2 μm. Aqueous polyolefin resin 100 parts Fine powder silica 5 parts Trimethylolpropane / triβ-aridinyl propionate 1 part Isopropyl alcohol 15 parts Water 25 parts

Subsequently, Ni was deposited on the surface of the adhesion auxiliary layer by a vacuum deposition method to form a magnetic thin film layer. The film thickness was adjusted to be 600Å as measured by a crystal oscillator. Further, a coating material for a protective layer prepared by the following composition was applied on the obtained magnetic thin film layer by a reverse roll coater to obtain a desired raw material for a magnetic recording medium. Aqueous polyolefin resin 5 parts Fine powder silica 1 part Isopropyl alcohol 3 parts Water 20 parts In addition, the pattern that becomes the fixed information is to form a metal thin film layer (in this case, a metal vapor deposition layer) after magnetic recording is performed on the magnetic recording layer. Then, the material (Ni in this case) forming the metal thin film layer is concentrated and deposited on the magnetic flux reversal interface portion of the magnetic recording. A JIS size magnetic card was punched out from the thus obtained raw material for a magnetic recording medium, and the following evaluation was performed.

That is, direct current degaussing was performed on the portion of the magnetic thin film layer where the fixed information was formed under the condition that the magnetic recording performed on the magnetic recording layer could be sufficiently erased. After that, when the fixed information was read using the reproducing magnetic head while applying the bias magnetic field of 500 gauss, the information according to the fixed information pattern could be read. This information was not erased even after DC demagnetization, and was fixed to the magnetic thin film layer as information independent of the magnetic recording layer. This information can be used as ID information of the magnetic card to prevent unauthorized use. In addition, when the magnetic recording / reproducing device for the card having a coercive force of up to 3000 Oersted was used to repeatedly perform normal magnetic recording, reproduction, and erasing on the portion of the card where the fixed information was not formed, no problem was found. I was able to use it. Furthermore, when a character pattern such as numbers and Chinese characters was printed on the part of this card where the fixed information was not formed using an electric discharge recording device, it could be printed and recorded in the same manner as a normal electric discharge recording card. did it.

[0022]

As described above, in the magnetic recording medium of the present invention, magnetically detectable fixed information for preventing unauthorized use corresponding to the information recorded in the magnetic recording layer is formed in the magnetic thin film layer. . Further, the unauthorized use information can be ID information (fingerprint information) which is different for each magnetic recording medium product. Furthermore, the magnetic recording medium of the present invention has an unprecedented function and effect that it is possible to print and record on the magnetic thin film layer on which the fixed information is formed by the discharge recording method. Further, the method of manufacturing the magnetic recording medium of the present invention is
This is an application of the method used in the conventional method of manufacturing a magnetic recording medium and the magnetic recording itself. Since no special device is required, it is possible to easily manufacture a magnetic recording medium that is almost impossible to illegally use. Have.

[Brief description of drawings]

FIG. 1A is a plan view of a magnetic recording medium of the present invention, and FIG. 1B is a magnetic state diagram after magnetization in a sectional view taken along line XX ′ in FIG.

FIG. 2 is a process diagram of a step of providing a magnetic recording layer.

FIG. 3 is a schematic diagram of a magnetic recording device.

FIG. 4 is a plan view showing the state of magnetic recording.

FIG. 5 is a cross-sectional view near the magnetic reversal interface.

FIG. 6 is a diagram showing a state in which magnetic thin film layers and fixed information are formed.

[Explanation of symbols]

 T track P magnetic flux reversal interface 1 substrate made of non-magnetic material 2 magnetic recording layer 3 adhesion auxiliary layer 4 magnetic thin film layer 5 protective layer 11 delivery reel 12 coating device 13 coating head 14 roll 15 magnetic field aligning device 16 dry part 17 rolls 18 take-up reel 21 magnetic head 22 magnetic original roll 23 magnetic original roll 24 magnetic recorded magnetic thick anti-roll 25 magnetic recording track 26 magnetic recording part 31 magnetic flux reversal interface part 32 fixed information pattern

Claims (3)

[Claims] 1. A magnetic recording layer made of a magnetic material having a coercive force of 200 oersted to 5000 oersted and a magnetic thin film layer having a coercive force of 1000 oersted or less are sequentially laminated on a substrate made of a non-magnetic material. A magnetic recording medium, characterized in that fixed information that cannot be added or erased later is formed on the layer. 2. In manufacturing the magnetic recording medium according to claim 1, after a magnetic coating material having a coercive force of 200 Oersted to 5000 Oersted is applied on a substrate made of a non-magnetic material and dried to form a magnetic recording layer. , Magnetic recording is performed, and thereafter, a magnetic thin film layer is formed on the magnetic recording layer by at least one method selected from vapor deposition, sputtering, and plating. A method of manufacturing a magnetic recording medium, characterized in that information is formed on the magnetic thin film layer. 3. A magnetic recording medium according to claim 1, wherein the magnetic thin film layer is provided with print recording by a discharge printing method.