JP3149420B2 - Thermal information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive information recording medium, and more particularly, to a heat-sensitive information recording medium capable of performing arbitrary recording which can be read by an optical reader.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable spread of cards having machine-readable information recorded on a magnetic recording medium. For example, ID cards, credit cards, cash cards, gift cards and telephone cards have been widely used. It is used in many fields, such as prepaid cards, tickets, coupons, and commuter passes. This kind of card is
A magnetic recording layer is provided on a card base, and information is magnetically recorded on the magnetic recording layer. Although magnetically recorded information is visually invisible, on the other hand, with the spread of magnetic reading machines, there is a risk that magnetic information may be intentionally erased or rewritten.

[0003] Also, information is recorded on the card surface by means such as a barcode, MICR, OCR, etc., but since the information can be read visually, it is easy to falsify such as falsification. There is a problem.
For this reason, these cards are required to have higher security. Are arranged so that the magnetic recording contents cannot be easily read from the outside.

[0004]

As one of such devices, a thermosensitive magnetic recording medium uses magnetic recording and thermosensitive recording as means for confirming a value record such as balance information. With the widespread use of magnetic recording information, it is possible to easily erase and rewrite magnetically recorded information with a normal magnetic head, and to modify or alter the information. There was a problem that alteration and falsification were easy and lacked security.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. One of the two types of information can be read out optically by mechanical means, and the difference in the threshold is determined. Another object of the present invention is to provide a highly reliable information recording card that can more effectively and reliably prevent forgery, falsification, and the like, and that can easily determine authenticity.

[0006]

The present inventors have Means for Solving the Problems] As a result of intense research in view of the above problems, the object of the present invention, on a substrate having a thermosensitive recording layer, the thermosensitive recording layer, heated The coloring portion has a light absorption in the infrared region at the time of coloring, and the coloring portion is adjusted so as to be a portion having at least two different coloring densities when in the heating coloring state.
The heat-sensitive information recording medium is characterized in that the light absorptance in the infrared region of the color-forming portion varies according to
The heat-sensitive information recording medium, wherein the portions having different coloring densities are portions having different thicknesses of at least two types of heat-sensitive recording layers , or portions having different contents of thermosensitive coloring materials, or a magnetic recording layer on a substrate, Make the magnetic recording layer invisible
The first hiding layer, the thermosensitive recording layer and the thermosensitive recording layer are invisible.
In a thermosensitive information recording medium, a second concealing layer is sequentially laminated, wherein the thermosensitive recording layer has a coloring portion having light absorption in an infrared region at the time of coloring by heating , and the coloring portion is heated.
At least two types of portions having different color densities when in a color developing state
Is adjusted so that the color-forming portion corresponds to the color-forming density.
It has been found that this is achieved by providing a thermosensitive information recording medium characterized by having different light absorptances in the infrared region .

[0007]

According to the present invention, there is provided a heat-sensitive information recording medium for recording information such as letters, numbers, and patterns on a heat-sensitive recording layer by thermally coloring the information with a thermal head or the like. The colored information is irradiated with infrared rays. When it does, it absorbs the infrared ray without reflecting it. At this time, the thermosensitive recording layer is provided with several kinds of density differences in advance separately from the recorded information pattern.
The infrared absorptivity differs depending on the magnitude of each concentration. Therefore, it is possible to determine the authenticity of the card by reading the difference between the reflectances of the respective portions simultaneously with the recorded information such as the pattern. In addition, the heat-sensitive recording layer is invisible due to the concealing layer thereon, and the colored pattern portion and the uncolored portion are on the same plane, making it even more difficult to detect the presence thereof, and forgery. ,
It is possible to prevent tampering and the like.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the heat-sensitive information recording medium of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an enlarged sectional view of one embodiment of the heat-sensitive information recording medium of the present invention. According to FIG. 1, the recording medium of the present invention has a magnetic recording layer 2 on a card base 1. And
On this, there is provided a first concealing layer 3 for making the magnetic recording layer made of a non-magnetic metal invisible, and further thereon, variable information is thermally recorded, and a thermosensitive recording layer 4 having a thickness step is provided. Layer 4
Has a second concealing layer 5 that makes invisible and a protective layer 6 that is provided as necessary. The magnetic recording layer 2 of the present invention may be formed over the entire surface of the substrate or a part thereof, and the size thereof is appropriately determined.

Here, the card base 1 is made of paper or a plastic sheet or the like. The magnetic recording layer 2 has γ
-Fe ₂ Co ₃ , Co-coated γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Ba
It is formed by dispersing magnetic powder such as ferrite or Fe in an appropriate resin or ink vehicle by a known coating method such as a gravure method, a roll coating method, or a screen printing method, and then drying. Its thickness is preferably from 10 to 15 μm.

The first concealing layer 3 is made of Ag, Cr, Al, Sn
A coating liquid in which a nonmagnetic metal powder such as a non-magnetic metal powder having a scale-like shape and a hiding power is dispersed in a binder solution such as polyvinyl alcohol and polymethacrylic acid resin is applied on the magnetic recording layer by the above-described coating method to form a coating. It was done.

The heat-sensitive recording layer 4 is composed mainly of a polymer binder such as an acrylic resin, a vinyl chloride resin or a polyester resin and a heat-sensitive coloring material. The heat-sensitive coloring material contains an organic metal salt or a leuco dye. There are methods to use. Examples of the organic metal salt include a chelate compound of ferric stearate and gallic acid. In this embodiment, a leuco dye is shown.Examples of the leuco dye include fluorene-based compounds, fluoran-based compounds, phthalide compounds, and the like. Each of the most suitable color developer and the one dispersed in the above-mentioned appropriate resin is dispersed to have a density difference (here, a thickness difference) of 4 to 10 μm by a gravure printing method, a screen printing method, an offset printing method, or the like.
The heat-sensitive recording layer 4 is formed by printing on the concealing layer 3 to a thickness of about 3 mm. The heat-sensitive coloring material is preferably 5 to 5 in the heat-sensitive recording layer.
20% by weight.

The second concealing layer 5 mixes a process ink (yellow, magenta, cyan) having a spectral reflectance characteristic as shown in FIG. 2 at an appropriate ratio, while transmitting infrared light but not visible light. The formed gray ink is formed by a screen or an offset printing method. Its thickness is preferably 1-3 μm.

The protective layer 6 is formed by dissolving a resin such as an acrylic resin, a vinyl chloride resin, a polyester resin, or nitrocellulose in a solvent such as toluene or xylene to a thickness of about 1 to 3 μm by a gravure method or a roll coating method. Form. In addition, a thermosetting resin and an ultraviolet curable resin are also used. A lubricant may be added to the protective layer for the purpose of improving the suitability for the thermal head.

A pattern such as a bar code or a mark is formed by a thermal head in which a predetermined energy is applied to the heat-sensitive recording layer 4 of the prepaid card having the above-mentioned structure. The pattern portion is colored green, blue-green, or black, but cannot be detected from the outside because it is concealed by the second concealing layer 5. Further, since the thermal layer is provided with a thickness difference, different coloring densities can be obtained depending on the thickness.

Next, a method of reading this pattern is performed by irradiating the card with infrared rays. That is, the colored pattern portion has a spectral reflectance characteristic as shown in FIG. 3, and in the infrared region having a wavelength of 700 nm or more, the uncolored portion shows a high reflectance, but the colored pattern portion reflects the infrared light. Not shown, and shows the absorption rate according to the concentration. That is, the higher the concentration of the heat-sensitive layer (here, the thicker one), the higher the absorption rate, and the lower the concentration (here, the thinner layer), the smaller the absorption rate. Therefore, it is possible to simultaneously read both the color development pattern itself and the absorptance according to the density, thereby discriminating the authenticity of the card and recognizing data such as the amount of money. As a specific method, when this color pattern portion is scanned by an infrared sensor, an output signal voltage corresponding to the pattern and the step can be obtained as shown in FIG. It is possible to determine the authenticity by confirming whether it is a predetermined one or not.

In another invention, since a difference in density is provided depending on the content of the heat-sensitive material, the higher the content, the higher the density and the higher the light absorption.

FIG. 5 shows an example of using this variable pattern in a store code. In this example, variable information (such as a barcode pattern) that can be written by the thermal head at the time of ticket issuance is used as the store name code of the store. When this is used, first, the pattern (variable information) of the thermosensitive recording layer is compared with the output difference (fixed information) generated by the thickness using an optical reader, and the following information is obtained only when the two information are as set. It can be used as a card, proceeding to reading and writing of magnetic information. Even if only one of them matches, the card cannot be used.

[0019]

As described above, according to the present invention, on a substrate made of paper, a plastic sheet or the like, when heated and colored, infrared rays are absorbed, but uncolored portions reflect infrared rays. By having a thermosensitive recording layer having a plurality of types of density differences, it is possible to provide a thermosensitive information recording medium that more reliably prevents forgery and tampering,
Furthermore, since the concealing layers that transmit infrared rays and make the heat-sensitive recording layer invisible are sequentially laminated, it is impossible to visually recognize the presence of the recorded machine-readable pattern.

A pattern such as a bar code recorded on the heat-sensitive recording layer can be arbitrarily recorded by a thermal head. Therefore, when comparing the method of the present invention with another method, for example, a method of printing and fixing a pattern on the first concealing layer with an ink containing an infrared absorber instead of the heat-sensitive recording layer of the present invention, In the former printing method, the pattern is inevitably limited to the same type or at most several types from the printing means, but the latter using the heat-sensitive recording layer of the present invention requires a thermal head. Since patterns can be freely recorded, very flexible use is possible.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing one embodiment of a thermosensitive information recording medium of the present invention.

FIG. 2 is a spectral reflectance characteristic curve of a second hiding layer .

FIG. 3 is a spectral reflectance characteristic curve of a colored portion and a non-colored portion of a thermosensitive recording layer.

FIG. 4 is a diagram showing the shape and magnitude of an output signal obtained according to a pattern and a step.

FIG. 5 is a flowchart of one embodiment of a method for reading a thermosensitive information recording medium according to the present invention.

[Main reference numbers]

DESCRIPTION OF SYMBOLS 1 Card base 2 Magnetic recording layer 3 First concealment layer 4 Thermal recording layer 5 Second concealment layer 6 Protective layer 7 Information recording pattern

Claims (4)

(57) [Claims] Claims: 1. A thermosensitive recording layer having a thermosensitive recording layer on a substrate, wherein the thermosensitive recording layer has a color-developing portion having light absorption in an infrared region at the time of coloring by heating , and the thermochromic portion is in a heating and coloring state. less <br/> Kutomo two adjusted so that different portions of the color density
Light absorption in the infrared region of the color-forming portion according to the color density.
A heat-sensitive information recording medium characterized by different rates . 2. The heat-sensitive recording layer according to claim 1, wherein the at least two portions having different color densities are at least two portions having different thicknesses of the heat-sensitive recording layer . Thermal information recording medium. 3. The heat-sensitive recording layer according to claim 1, wherein the at least two types of portions having different coloring densities are portions having different contents of at least two types of thermosensitive coloring materials of the thermosensitive recording layer. The heat-sensitive information recording medium according to claim 1. 4. A magnetic recording layer on a substrate, wherein the magnetic recording layer is
First hiding layer to be visible, heat-sensitive recording layer, and the heat-sensitive recording layer
In a heat-sensitive information recording medium obtained by sequentially laminating a second concealing layer that makes invisible a, the heat-sensitive recording layer has a color-developing portion having light absorption in an infrared region at the time of heating and coloring, and the color-forming portion is Adjustment is made so that at least two types of portions having different color densities are formed in the heated color developing state.
A heat-sensitive information recording medium characterized in that the light-absorbing rate of the colored region in the infrared region is different .