JP2001134728A - Thermosensible magnetic recording medium and recording/ reading-reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information recording medium provided with an information recording part capable of easily recording information by existing method and means but difficult in fraudulent alteration by dissolving conventional defects occurring at the time of recording magnetic information. SOLUTION: The information is thermosensitively or pressure-sensitively recorded on the medium in which a recording layer 3 having appearance similar to ordinary magnetic stripes and containing ferromagnetic particulates is formed on a substrate 2, then the medium is magnetized. Thus only a part 3b subjected to thermosensible recording or pressure-sensitive recording is selectively magnetized, so that the recording medium difficult in fraudulent alteration can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for heat-sensitive recording / magnetic reading which is suitable for use in a field where forgery or alteration is a problem. It is provided with a recording layer that can be replaced with a forgery, and has difficulty in forgery and alteration. Also, the present invention
The present invention relates to a method for recording information using such a medium and reading and reproducing the recorded information.

[0001]

2. Description of the Related Art Counterfeiting and falsification poses a problem, such as stock certificates, securities, gift certificates, cash vouchers, and cash advance payment cards for transportation (collectively referred to as "gold vouchers").
Also, a bank card, a credit card, and other ID cards (collectively, "cards" after "and") and the like are included. Cash vouchers have an economic value equal to or more than the indicated face value, and in some cases have an economic value similar to cash. Cards enable the withdrawal of bank deposits and credit-free credit transactions when purchasing goods based on the ID information recorded on the card. Although there is no cash-like value like this, its use brings indirect but still economic value.

[0002] Since these cash vouchers and cards have great economic damage when used illegally, various measures have been taken to prevent forgery and tampering. Various techniques have been devised, such as elaborating designs such as printing, having a plurality of means for holding information, and holding some of the means which are difficult to manufacture and process.

Normally, information recorded on cash vouchers or cards includes visually observable information (printed characters, embossed characters, a signature of a holder, etc.), and information (magnetic information) readable by physical means. Information, optical information, or electronic information), etc., and are recorded in portions suitable for recording the respective information, which are set on cash vouchers and cards.

[0004] Among various types of information recording, magnetic information recording is widely performed in the field of recording media. However, there is a disadvantage that information is lost when carelessly touched with a magnet or the like. Is also well known, and can be easily tampered with by a person with improper intent. If the magnetic information is converted to a magnetic barcode, falsification becomes difficult. However, since the magnetic barcode is formed by printing or the like, it is not suitable to include individual information as ID information.

[0005]

SUMMARY OF THE INVENTION In the present invention, the conventional disadvantages that occur when recording magnetic information are eliminated, and the recording itself can be easily performed by existing methods and means, but information recording that is difficult to falsify is performed. It is an object to provide an information recording medium having a section.

[0006]

Means for Solving the Problems The present inventor forms a resin layer containing ferromagnetic fine particles on a base material, and performs thermal recording with a thermal head in place of performing normal magnetic recording thereon. However, since a region having a small magnetic anisotropy and a region having a large magnetic anisotropy are formed separately, when a magnetic field is externally applied to the entire resin layer, magnetic recording that can be read by a magnetic head is performed. Turned out to be possible.

The first invention relates to a thermosensitive magnetic recording medium characterized in that a thermosensitive magnetic recording layer comprising a layer in which ferromagnetic fine particles are dispersed in a polymer matrix is laminated on a substrate. The second invention relates to the thermosensitive magnetic recording medium according to the first invention, wherein the diameter of the ferromagnetic fine particles is 100 nm or less. A third invention relates to the thermosensitive magnetic recording medium according to the first or second invention, wherein the substrate is a card substrate. According to a fourth aspect of the present invention, the thermosensitive magnetic recording layer of the thermosensitive magnetic recording medium according to any one of claims 1 to 3 is subjected to heat-sensitive recording or pressure-sensitive recording to obtain an area having a small magnetic anisotropy and a magnetic anisotropy. Forming information comprising a large area, and then magnetizing the formed area having a small magnetic anisotropy and the area having a large magnetic anisotropy to form magnetic information; The present invention relates to a recording / reading / reproducing method characterized by magnetically reading / reproducing information.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of the present invention will be described with reference to the drawings. FIG. 1 shows a thermosensitive magnetic recording medium 1 according to the present invention.
FIG. 2 is a schematic view showing a recording method using the thermosensitive magnetic recording medium 1 of the present invention, and FIG. 3 is a cross-sectional view schematically showing a recorded state. is there.

FIG. 1A shows a very basic structure of a thermosensitive magnetic recording medium 1 when the present invention is applied to a card. The card 1 has a thermosensitive magnetic recording layer 3 on a card base 2.
Are arranged. The present invention is not limited to a card, but can be widely applied to a field in which a magnetic recording medium is used, but a card which is a typical magnetic recording medium will be described as an example.

[0010] The card base 2 is based on long-standing custom,
It usually has a predetermined size and shape set internationally. In this example, the thermosensitive magnetic recording layer 3 is laminated at a position slightly away from one long side along the longitudinal direction of the card base material 2 and has a stripe shape with a width of about 6 mm. FIG. 1B corresponds to a cross-sectional view taken along line AA of the card of FIG.
Is constructed such that the entire thickness of the layer is embedded inward from the surface of the card substrate 2 so that the exposed surface of the thermosensitive magnetic recording layer 3 is flush with the surface of the card substrate 2.

As the base material 2, a material such as paper, a plastic sheet, a metal foil or a metal plate is used alone or in combination of the same or different materials. Select and use it in consideration of the required rigidity, flexibility, adhesiveness at the time of processing, printability, and if necessary, embossability according to the application.

As a plastic sheet suitable for the base material 2, a sheet made of a vinyl chloride resin is often used because of its suitability for processing, but a polyethylene terephthalate resin (= P
ET), polybutylene terephthalate resin (= PB
T), or a polyester resin such as polyethylene-2,6-naphthalate resin (= PEN), or a sheet of a polyolefin-based resin or another resin. The substrate 2 is subjected to processing such as printing that is usually performed on cash vouchers or cards.

The thermosensitive magnetic recording layer 3 is preferably composed of ferromagnetic fine particles having a particle diameter of 100 nm or less (generally called ultrafine particles) at which the melting point drops due to the surface tension thereof. Is 10 nm.

As the ferromagnetic material, a metal such as iron, cobalt or nickel, or an alloy of these metals or other metals is used. Generally, when the particle diameter of the metal fine particles is 100 nm or less, the melting point is lowered due to the surface tension. When heat or pressure, or heat and pressure, is applied to the ultrafine particles having a lowered melting point, the surface is melted and bonded at a lower temperature than the original melting point, and it becomes as if sintered. In the state where the ultrafine particles are dispersed in the binder, the magnetic anisotropy is very small,
The squareness ratio becomes smaller. In the state of being sintered as described above, anisotropy occurs due to the shape. Especially when it is shaped like a bar code, it has anisotropy in its long side direction,
The squareness ratio is high in the long side direction. By detecting the difference in the squareness ratio, the difference in the residual magnetization, or the difference in the magnetic permeability, information can be recorded / reproduced.

The ferromagnetic fine particles can be obtained by pulverizing the ferromagnetic material and dispersing it in a polymer binder to form the thermosensitive magnetic recording layer 3. As another method, see Japanese Patent Application Laid-Open No. 5-62159. No., ferromagnetic metal compound such as ferromagnetic metal carboxylate, reducing agent, polymer binder, and paint with solvent,
After obtaining a coating film which is applied to the substrate 2 or the like and dried, a method of reducing the ferromagnetic metal compound in the coating film by heating to form metal fine particles may be used. In addition to coating on the substrate, by applying to a different substrate, not the substrate of the magnetic recording medium, and then pasted or formed by coating on a peelable substrate, by the method of transfer Is also good.

In the above, iron (II) is used as a ferromagnetic carboxylate for obtaining metal fine particles by reduction.
I) acetylacetonate, iron cyclohexylbutyrate (I
II), cobalt acetate, cobalt (II) acetylacetonate, cobalt (III) acetylacetonate,
Cobalt (II) benzoate, cobalt gluconate (I
I), cobalt stearate, cobalt (II) phenyldiazosulfonate, cobalt cyclohexyl butyrate (I
I), cobalt naphthenate, nickel acetate, nickel (II) acetylacetonate, nickel (II) cyclohexyl butyrate, nickel naphthenate and the like.

As the reducing agent for reducing the ferromagnetic metal compound in the polymer binder of the coating film, 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis- (4-ethyl 6-t-butylphenol), 2-t-
Butyl-6- (3'-t-butyl-5'-methyl-2 '
-Hydroxylbenzyl) -4-methylphenyl acrylate, hydroquinone and the like can be used.

FIGS. 2 and 3 show how recording, reading and reproducing are performed. Using a thermal printer equipped with a thermal head 4 on the thermal magnetic recording layer 3 or a pressure printer equipped with a pressure-sensitive head, thermal recording or pressure-sensitive recording is performed, and signals, characters, bar codes, images, etc. By outputting the information, the layer 3b, which originally has a small magnetic anisotropy, exhibits magnetic characteristics (high squareness ratio, high remanence, high magnetic susceptibility, high magnetic permeability) according to the output pattern; and A portion 3a exhibiting other magnetic properties (low squareness ratio, low remanence magnetization, low magnetic susceptibility, low magnetic permeability) is obtained.

When a magnetic field is applied to the layer 3 in this state by a magnetic head, a large magnetization remains in the portion 3b having a large squareness even after the magnetic field is removed, but remains in the portion 3a having a small squareness. Since the magnetization is reduced, a pattern composed of the portion 3b having a large residual magnetization and the portion 3a having a small residual magnetization is formed. Therefore, the state of the magnetization can be detected by a magnetic head or the like. As described above, writing of information by heat or pressure, reading and reproduction of information by magnetic means can be performed.

Therefore, the thermosensitive magnetic recording medium of the present invention magnetizes and records information after applying the heat-sensitive technique or the pressure-sensitive technique, and reads or reproduces the recorded information magnetically.
Alternatively, it is used for a recording / reading / reproducing method in which information is recorded by applying a heat-sensitive method or a pressure-sensitive method, magnetization is performed prior to reproduction of the information, and then the information is magnetically read / reproduced. .

The information is printed on the thermosensitive magnetic recording layer 3 by a thermal printer or a pressure-sensitive printer, and is classified into a ferromagnetic portion 3b and another paramagnetic portion 3a. The magnetic recording layer 3 itself does not look different from the state before printing, and has no difference from the normal magnetic recording layer.

Suitable for recording, reading and reproducing as described above,
The thermosensitive magnetic recording layer 3 is formed by dispersing ferromagnetic fine particles having a particle size of 100 nm or less, more preferably 10 nm or less in a polymer binder and dissolving or dispersing the fine particles together with a solvent or the like to form a thermosensitive magnetic recording layer forming composition. It is formed by preparing a product and applying it on the substrate 2 or the like.

As the polymer binder in the above,
Cellulosic resins such as nitrocellulose, cellulose acetate, cellulose butyrate, or ethyl cellulose,
Chloride rubber, cyclized rubber, polyamide resin, polyvinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin, ethylene /
One or more of vinyl acetate copolymer resin, chlorinated polypropylene, acrylic resin, polyurethane resin, styrene malee resin, acrylic resin, urethane resin and the like can be selected and used.

A main component such as ferromagnetic fine particles, a polymer binder, a solvent or a dispersion medium, and additives such as a surfactant or an antisettling agent are dissolved or dispersed to form a thermosensitive magnetic recording layer. Used as a composition.

In order to form the thermosensitive magnetic recording layer 3 by directly applying the composition for forming a thermosensitive magnetic recording layer onto the substrate 2, a known coating method, for example, a roll coating method, a gravure coating method, a spray coating method, or the like is used. Or a kiss coating method, or a known printing method such as a gravure printing method, a flexographic printing method, or a silk screen printing method.

The thermosensitive magnetic recording layer 3 may be formed directly on a base material, or may be formed on an appropriate base material by cutting it into a predetermined size and pasting it. Alternatively, the thermosensitive magnetic recording layer 3 is coated and formed on a temporary substrate whose surface is peelable, and usually, an adhesive is further laminated on the outermost layer.
The thermosensitive magnetic recording layer 3 can be formed on the thermosensitive magnetic recording medium such as the card base material 2 by thermal transfer or the like.

In the description of the base material 2, it has been described that processing such as printing which is usually performed on cash vouchers or cards is given. However, the following processing including printing is a known processing. And may be arbitrarily selected and applied. First,
By printing, as characters and pictures, (1) the name of the issuer of the vouchers or cards, the name of the voucher or card, or the name of the association if distributed to the member, such as the ground pattern, character, (2) (3) expiration date, (4) mark for indicating the direction of insertion into the recording / reader, and (5) general precautionary notes on use, etc., on the surface of the base material 2. Alternatively, it can be formed on the back surface. Since printing may be performed every time a voucher or card is issued, a layer capable of thermal printing may be formed so as to be suitable for such use.

Various recording layers may be arbitrarily selected and provided on the substrate 2. (6) a normal magnetic recording layer,
(7) Holograms and diffraction gratings, (8) Writing layers made of materials easy to write for signatures, (9) ICs and LSIs with arithmetic and memory units, (10) Sublimation transfer and photo pasting An area where an image can be formed, and the like.

Each of the above-mentioned items (1) from the formation of characters and patterns to (10) providing an area capable of sublimation transfer or the like may be provided directly on the outermost surface of the substrate 2.
When the base material 2 is formed by integrating a plurality of sheets by hot pressing, the sheets may be inserted between the sheets and stacked. Except for the case where it must be exposed to the outermost surface for recording or the like, forming it inside the outermost surface can prevent damage due to abrasion, contamination, and the like.

In addition to the above-described processing, bookbinding and binding with wire, thread, or adhesive for forming each thermosensitive magnetic recording medium can be performed as necessary.

[0031]

According to the first aspect of the present invention,
While having a normal magnetic recording layer, heat-sensitive recording or pressure-sensitive recording, then by magnetizing, etc., it is impossible to perform normal magnetic recording and reading and reproducing methods, and recording and reading and reproducing are possible. It is possible to provide a thermosensitive magnetic recording medium which has no problem in manufacturing and can sufficiently suppress forgery and alteration. In addition, since data is not written on this thermosensitive magnetic recording medium unless thermal or pressure-sensitive recording is performed first, forgery / falsification is required only by preparing means for magnetic recording and erasing. Cannot be performed, and once the thermal recording or the pressure-sensitive recording is performed,
Since there remains a record that cannot be erased by a normal method, there is also an advantage that alteration becomes difficult. According to the second aspect of the invention, it is possible to provide a thermosensitive magnetic recording medium in which the effect of the first aspect of the invention is more reliable. According to the invention of claim 3, claim 1
In addition to the effects of the second aspect, it is possible to provide a highly sensitive thermosensitive magnetic recording medium that has a high effect of suppressing forgery and falsification for cards that are widely used and frequently used by individuals.
According to the fourth aspect of the present invention, recording can be performed on the thermosensitive magnetic recording medium according to any one of the first to third aspects by performing thermal recording or pressure-sensitive recording, and reading can be performed by performing magnetization. Thus, information can be read out and read out by magnetic means, and as a means for that,
It is possible to provide an easy-to-use recording / reading / reproducing method that can be used by combining well-known and widely used means.

[Brief description of the drawings]

FIG. 1 is a diagram of a thermosensitive magnetic recording medium applied to a card.

FIG. 2 is a diagram showing a state of recording on a thermosensitive magnetic recording medium.

FIG. 3 is a diagram schematically showing a recorded state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal magnetic recording medium 2 Base material 3 Thermal magnetic recording layer 4 Thermal head

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C005 HA01 HB10 JA02 JA18 JA19 JA26 JB19 KA02 KA15 KA21 KA25 KA37 KA41 KA70 LA03 LA20 LB08 LB10 LB18 5B035 AA13 BB02 BB04 BC01 BC02 5D006 BA08 BA19 DA01 FA00

Claims (4)

[Claims] 1. A thermosensitive magnetic recording medium characterized in that a thermosensitive magnetic recording layer comprising a layer in which ferromagnetic fine particles are dispersed in a polymer matrix is laminated on a substrate. 2. The ferromagnetic fine particles have a diameter of 10 nm to 10 nm.
2. The thermosensitive magnetic recording medium according to claim 1, wherein the thickness is 0 nm. 3. The thermosensitive magnetic recording medium according to claim 1, wherein the base material is a card base material. 4. A thermosensitive or pressure-sensitive recording is performed on the thermosensitive magnetic recording layer of the thermosensitive magnetic recording medium according to claim 1, wherein the magnetic anisotropy area is large and the magnetic anisotropy is large. And forming the magnetic information by magnetizing the formed area having a small magnetic anisotropy and the area having the large magnetic anisotropy, and forming the magnetic information. Recording / reading / reproducing method for magnetically reading / reproducing data. [0001]