JPH0761178A - Information recording medium - Google Patents

Abstract

PURPOSE:To provide an information recording medium of high security and good electromagnetic conversion characteristics in which an information to distinguish false from truth which can not be discriminated visually, and can be read only by using a proper means and to prevent forgery for every individual information recording medium is retained. CONSTITUTION:In an information recording body constituted by forming a magnetic layer containing an infrared ray absorbent, a heat degradation printing layer 3 and a masking layer 4 which is transparent in an infrared ray area and opaque in a visible ray area laminated successively on a substrate 1, the surface roughness of the substrate 1 is 1.2mum or under based on the average roughness in a center line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information recording such as prepaid cards, cash cards, credit cards, various voting tickets such as betting tickets, pass tickets such as tickets and commuter tickets, and various tickets in which value information is held in a magnetic layer. It concerns media.

[0002]

2. Description of the Related Art The information recording medium of the present invention can be used as an information recording medium such as various voting tickets such as prepaid cards, cash cards, credit cards, betting tickets, pass tickets such as tickets and commuter tickets, and various tickets. However, in general, these information recording media hold information about the value itself that the information recording media bears, such as the amount of money and the expiration date. Hereinafter, this information is referred to as "value information". In addition, there is a case where information provided for the purpose of preventing unauthorized use of these information recording media is held. Hereinafter, this information is referred to as "authenticity determination information". Further, these information recording media may hold advertising information and information for planning such as fortune-telling for the purpose of service to customers and sales promotion. Hereinafter, this information is referred to as "attached information".

With the recent widespread use of various types of cards and the like, there are various risks of forgery, tampering, and illegal use, and new fraud prevention techniques corresponding to these risks are constantly demanded. In other words, "security information" with high security that is difficult to forge and alter is desired.

Therefore, various methods have been proposed for preventing counterfeiting or falsification of securities, boarding tickets, commuter tickets, betting tickets, prepaid cards and the like. Among them, as a magnetic method, a magnetic recording layer is provided on the support, and when recording information, the recording density or the signal encoding method is changed so that the general device cannot read or write, There is a method of providing a magnetic shield layer on the magnetic recording layer. These methods mainly aim to prevent the "value information" held by the information recording medium from being illegally read or rewritten.

On the other hand, for preventing forgery of the information recording medium,
It can be considered that the information recording medium is provided with "authenticity determination information" for determining whether the information recording medium is genuine. Among these methods, as a method that uses vision, a method that uses a hologram that uses light interference to make a three-dimensional image appear when exposed to light, and a pattern is printed invisible using fluorescent ink. There is a method of printing a hidden character that emits fluorescence when exposed to ultraviolet rays so that the pattern can be visually confirmed. Furthermore, JP-A-59-3
In Japanese Patent Application Laid-Open No. 8099, Japanese Patent Application Laid-Open No. 61-297192, Japanese Patent Application Laid-Open No. 64-87395, etc., invisible information is utilized by utilizing the difference in the absorption coefficient and the reflectance with respect to light having a wavelength other than the visible light region. Is described for how to form. Further, JP-A-59-44082 and JP-A-2
Japanese Patent Laid-Open No. 6193 and Japanese Patent Laid-Open No. 3-231394 disclose methods for utilizing forgery prevention information using a thermochromic material.

Alternatively, it is considered to provide "authenticity determination information" by using a magnetic method. Among these, JP-A-62-33323 and JP-A-3-130
The method disclosed in Japanese Patent Laid-Open No. 197 is to provide "authenticity determination information" on an information recording medium having a high coercive force layer and a low coercive force layer laminated by appropriate means. However, the "authenticity determination information" given by these methods is basically recorded by a magnetic recording device, and all the information recording media have the same morphological structure except for the recording pattern of the magnetic layer. ing. Therefore, as long as the magnetic recording method is known, the same information recording medium can be formed by rewriting the information to the information recording medium originally holding different information, and so-called " It is hard to say that there is sufficient security against counterfeiting, which is called "alteration." On the other hand, a method of providing a magnetic bar code or the like to give unique information to the information recording medium has been reported. For example, Japanese Patent Laid-Open No. 1-269227,
JP-A-2-98498 and JP-A-3-252901
In the publication, there is a portion having a different coercive force at an appropriate position in the magnetic layer, and information for preventing forgery using the pattern is shown. According to these methods, since the respective information recording media have different morphological structures, it is difficult to "alter" by simply rewriting the information. However, in these methods, the "authenticity determination information" formed on the information recording medium is
It includes a problem that it is restricted to a specific limited pattern due to complexity in manufacturing. In other words, the problem with these methods is that there is a high probability that multiple information recording media will have the same "authenticity determination information", and "authenticity determination information" as "fingerprints" on the information recording media "
There is a point that the effect of can not be fully exerted.

In addition, if one or more layers are newly provided on the magnetic layer in order to give "authenticity determination information" to the information recording medium, a magnetic signal is generated due to a spacing loss due to these layers. There is a problem that the reading output and the resolution are reduced.

[0008]

As described above, the "authenticity determination information" or fingerprint information provided on the information recording medium is preferably different for each information recording medium. It is necessary to avoid the existence of "authentication information". Furthermore, those "authentication information"
Is preferably a random pattern that is difficult to duplicate. Furthermore, the anti-counterfeiting information cannot be read in a normal state, and the anti-counterfeiting effect can be further enhanced if the information can be read only by using an appropriate means. In addition, these "authentication information"
If the operation of forming the information recording medium on the information recording medium is complicated, the manufacturing cost will increase, and even if the system has a high security, it may not actually be used, so it is important that it is simple and low cost. Is. Moreover, it is unavoidable that the electromagnetic conversion characteristics in magnetic recording fall below the usable range because "authenticity determination information" is given to the information recording medium.

[0009]

The present inventor holds "authenticity determination information" which is readable only by using such appropriate means and is unique to each information recording medium. However, as a result of various studies in order to obtain a new information recording medium with higher security and good electromagnetic conversion characteristics of magnetic recording simply and at low cost, as a result, (1) infrared absorber was formed on the support. An information recording medium comprising a magnetic layer containing (1), a thermal destruction printing layer formed of a metal thin film layer, and (3) a concealing layer which is transparent in the infrared region and opaque in the visible region and are sequentially laminated. The present invention has led to the invention of an information recording medium characterized by having a center line average roughness (Ra) of 1.2 μm or less. Next, the principle of giving the intended “authenticity determination information” to the information recording medium of the present invention will be described.

The metal thin film layer, which is the thermal destruction printing layer of the information recording medium of the present invention, has been used for a long time as a thermal destruction thermosensitive layer, mainly for displaying the balance and the like in prepaid cards and the like. In this case, the metal thin film layer is a vapor deposition layer of tin or aluminum, and a colored layer such as a magnetic layer is provided under the vapor deposition layer, and an appropriate thermal energy is applied from above the vapor deposition layer with a thermal head or the like. Then, the vapor-deposited layer shrinks only at that portion and loses the hiding power, so that the colored portion of the lower layer is exposed, and the intended printing of information is achieved.

When used only for displaying various kinds of information as described above, it is premised that the human can visually confirm the information, and therefore at least the colored layer such as the magnetic layer must have absorption in the visible light region. Furthermore, when this colored layer contains an infrared absorbent, the vapor deposition layer of tin, aluminum, etc. reflects infrared rays, so that the infrared reflectance differs between the printed and non-printed areas due to heat. Can be done. Therefore, it is possible to form “authenticity determination information” that can be determined only by infrared rays by utilizing this difference in reflectance of infrared rays. Moreover, since this "authenticity determination information" can be formed in an arbitrary pattern by the thermal head, it is possible to form a different pattern for each information recording medium, and further to make the pattern a random one that is difficult to forge. It is also possible to do so.

However, as it is, since the "authenticity determination information" formed on the information recording medium can be easily visually observed, the effect of preventing forgery is small. Therefore, it is necessary to hide this "authenticity determination information". Therefore, by providing a concealing layer that is transparent in the infrared region and opaque in the visible light region on the metal thin film layer that is the thermal destruction printing layer, the "authenticity determination information" can be concealed, and this makes it very It is possible to achieve high security. In this way, the information recording medium of the present invention can easily form "authenticity determination information" that is invisible and difficult to forge, which is different for each information recording medium.

However, when a thermal destruction printing layer for forming "authenticity determination information" and a masking layer for masking the formed "authenticity determination information" are provided on the magnetic layer as described above, The electromagnetic conversion characteristics of magnetic recording tend to deteriorate due to spacing loss due to those layers. These appear in the form of, for example, a reduction in reading output or a reduction in resolution. Naturally, this spacing loss can be improved by reducing the thickness of the thermal destruction printing layer and the concealing layer, but in order to make the functions of each layer sufficient, it is necessary to secure a certain thickness. Specifically, in order to uniformly conceal the magnetic layer and to secure an appropriate infrared reflectance, the thermal destruction printing layer has a thickness of 10 nm to 10 μm.
Is preferable, and 0.05 μm to 1.0 μm is particularly preferable. The hiding layer needs to be 0.5 μm to 5 μm, preferably 1 μm to 3 μm in order to sufficiently hide the “authenticity determination information” formed on the thermal destruction printing layer. Moreover, when a protective layer is further provided for the purpose of improving the durability of the information recording medium, the distance between the magnetic layer and the magnetic head is further increased by 1 μm to 2 μm.

However, what determines the electromagnetic conversion characteristics of the information recording medium of the present invention is not only the film thickness of the thermal destruction printing layer and the concealment layer but also the surface roughness of the magnetic layer itself. Further, the surface roughness of this magnetic layer is greatly affected by the surface roughness of the support. In view of this point, the surface roughness of the magnetic layer is made good, and even if the spacing loss occurs due to both the thermal destruction printing layer and the concealment layer, the electromagnetic conversion characteristics of the information recording medium are set within the usable range. As a result of an examination aiming at maintaining, it was concluded that the surface roughness of the support is preferably 1.2 μm or less in terms of center line average roughness (Ra). This centerline average roughness is
The cut-off value was 0.8 mm using a stylus type three-dimensional surface roughness meter "Surfcom" manufactured by Tokyo Seimitsu Co., Ltd. In addition, the needle used for the measurement has a stylus tip of 1 μm.
When a stylus tip having a tip of 5 μm was used, it could not be used because the load of the stylus was large and the sample surface was damaged. Next, each component of the invention will be described in detail.

The support used in the information recording medium of the present invention includes paper, various non-woven fabrics, woven fabrics, synthetic resin films,
A foamed film, synthetic resin laminated paper, synthetic paper, metal foil, glass, etc., or a composite sheet in which these are combined can be arbitrarily used according to the purpose, but is not limited thereto. However, in any support, the value of the center line average roughness (Ra) obtained by the above-mentioned measuring means is preferably 1.2 μm or less, and 0.7 μm
More preferably, it is m or less.

As the magnetic material used in the magnetic layer of the information recording medium of the present invention, a magnetic material used in known magnetic recording materials can be used. For example, γ-Fe ₂
O ₃ , Fe ₃ O ₄ , Co-containing iron oxide, CrO ₂ , metal powder,
Examples include Ba ferrite and the like.

The magnetic dispersant is lecithin,
A vinyl acetate-vinyl chloride-maleic anhydride copolymer, a vinyl acetate-vinyl chloride-vinyl alcohol copolymer, polyvinyl butyral, polyester, or a water-soluble polyacrylic acid-based dispersant can be used.

Further, as a binder for the magnetic layer, a vinyl chloride-vinyl acetate copolymer, a partially saponified product thereof, a vinyl acetate-vinyl chloride-maleic anhydride copolymer, a polyurethane, a modified polyurethane, a styrene-acrylic acid copolymer. , Saturated polyester, unsaturated polyester, epoxy resin, phenol resin, nitrocellulose, chlorinated polyethylene, melamine resin, polyvinyl butyral resin and the like can be used, and a curing agent such as polyisocyanate can be used in combination if necessary.

The infrared absorber contained in the magnetic layer is a dye that absorbs light having a wavelength of 700 nm to 1 mm, but a dye that absorbs near infrared light of 700 nm to 2500 nm is preferable for practical use. Examples thereof include system dyes, squarylium dyes, methine dyes, naphthoquinone dyes, quinoneimine dyes, quinonediimine dyes, 1,2-dithiol metal complexes, other organic metal complexes, and carbon black.

Te, Sn, In, Al, Bi and P are used as the metal constituting the thermal destruction printing layer of the information recording medium of the present invention.
Metals such as b and Zn, or alloys thereof can be used. The thermal destruction print layer can be formed of these metals and alloys by a vacuum deposition method, a sputtering method, a plating method, or the like.

For the hiding layer of the information recording medium of the present invention, an ink obtained by mixing known process inks (yellow, magenta, cyan) described in JP-A-64-87397 in an appropriate ratio is subjected to an offset or screen printing method. And the like.

The layer structure of the information recording medium of the present invention is such that (1) a magnetic layer containing an infrared absorbent, (2) a thermal destruction printing layer, and (3) a transparent and visible infrared region on a support. Although a concealing layer that is opaque in the light region is sequentially provided, an undercoat layer may be provided between the support and the magnetic layer for the purpose of adhesiveness, durability, heat insulation and the like. In addition, a protective layer may be provided on the concealing layer depending on the purpose of abrasion resistance, chemical resistance, durability and the like. When the undercoat layer and the protective layer are provided, as the resin used for the undercoat layer and the protective layer, resins such as polyester, polycarbonate, polyvinyl alcohol, acrylic resin, and nitrocellulose can be used. The undercoat layer and the protective layer may be composed of a plurality of layers of 2 to 3 layers or more. Also, the "authenticity judgment information" of the information recording medium does not need to be provided on the entire surface of the thermal destruction print layer, and is displayed for "value information" and "accessory information" except for the part used for "authenticity judgment information". Since it can be used, the hiding layer only needs to be applied to the portion where the "authenticity determination information" is formed.

[0023]

Since the information recording medium of the present invention uses a special method of measuring a pattern due to a difference in reflectance of infrared rays, the "authentication determination information" has very high security. Moreover, it is not visible due to the presence of the hiding layer. These "authentication determination information" can be arbitrarily formed for each information recording medium by a thermal head or the like, and the effort for forgery or alteration is immeasurable. Furthermore, from the two pieces of information "value information" and "authenticity information", "encryption information" is formed by a specific function, and this is recorded for each information recording medium, and these three pieces of information are recorded for each use. If you have a system to compare,
Counterfeiting and even alteration are almost impossible.

[0024]

EXAMPLES Examples of the present invention will now be described in detail with reference to the drawings, but the present invention is not limited to this mode.

Example 1 FIG. 1 is an example in which the information recording medium of the present invention is applied to a prepaid card and shows the layer structure of its cross section. In the prepaid card of Example 1, the magnetic layer 2, the thermal destruction layer 3, the concealing layer 4, and the protective layer 5 are formed on the support 1 in this order. Next, specific manufacturing methods of these components will be described.

As the support, general paper having a basis weight of 180.0 g / m ² and a thickness of 171 μm was used. The surface roughness of this paper is
The measurement result (Ra) was 1.15 μm.

(A) Magnetic Layer Magnetic Material (Barium Ferrite “MC127” manufactured by Toda Kogyo Co., Ltd.) 100 parts Water 85 parts Dispersant (“SN Dispersant 5468” manufactured by San Nopco Co., Ltd.) 1.5 parts The above composition Was dispersed for 4 hours using a paint conditioner to prepare a preliminary dispersion liquid. Next, the following composition was added to this preliminary dispersion liquid, followed by stirring with a three-one motor for 1 hour to obtain a magnetic coating liquid. Binder (styrene-acrylic ester copolymer emulsion “DM60” manufactured by Hoechst Synthetic Co., Ltd.) 120 parts Thickener (methyl cellulose “Chirose H1000P” manufactured by Hoechst Synthetic Co., Ltd.) 0.25 part (Hoechst Synthetic Co., Ltd.) Carboxy Copolymer Emulsion "Viscarex HV30" 2.7 parts 10% Ammonia water 0.6 part Infrared absorber (carbon black) 8.0 parts This magnetic coating liquid is applied to the support in a thickness of 10 μm. Immediately after coating, a magnetic field of 2000 G was applied to orient the magnetic particles.

(B) Thermal Destruction Printing Layer Next, a 0.1 μm thick metal tin layer was provided on the magnetic layer by a vacuum deposition method.

(C) Concealing Layer Next, yellow, magenta, and cyan process inks were mixed in a ratio of 2: 3: 3, and this was printed on the tin vapor deposition layer so that the film thickness was 2 μm.

(D) Protective Layer Vinyl Chloride-Vinyl Acetate-Vinyl Alcohol Copolymer (“S-REC A” manufactured by Sekisui Chemical Co., Ltd.) 3 parts MEK 30 parts Toluene 30 parts A film of the above composition on the hiding layer. A protective layer was prepared by coating so as to have a thickness of 1 μm and drying.

A bar code pattern was printed on the information recording medium thus manufactured with a thermal head at an energy of 100 mJ / mm ² to form "authenticity determination information". FIG. 2 shows a cross section of the prepaid card at this time, and 6 shows a bar code pattern at this time. The portion printed by the thermal head suffers thermal destruction and cannot reflect infrared rays, and since infrared rays are absorbed by the infrared absorbing agent in the magnetic layer, when the reflectance of infrared rays is measured, the area where thermal destruction occurs ( The difference between the printed area) and the non-printed area (comparative printed area) clearly appears. Of course, this "authenticity determination information" cannot be visually confirmed because of the hidden layer.

Example 2 Instead of the general paper having a (Ra) of 1.15 μm as the support used in Example 1, a polyethylene laminated paper having a surface roughness (Ra) of 0.64 μm was used. A prepaid card was manufactured in the same manner as in Example 1.

Comparative Example 1 Instead of the general paper having a (Ra) of 1.15 μm used in Example 1 as the support, a general paper having a surface roughness (Ra) of 1.3 μm was used. A prepaid card having the same structure as in Example 1 was manufactured.

Next, the static magnetization characteristics, the electromagnetic conversion characteristics, the "authenticity determination information" of each prepaid card were read by infrared rays, and the concealability of the "authenticity determination information" was evaluated.
Here, the static magnetization characteristic is measured by a squareness ratio using a vibrating sample magnetometer ("BHV-35" manufactured by Riken Denshi Co., Ltd.), and the electromagnetic conversion characteristic is measured by a card reader / writer (Sanwa Newtec Co., Ltd.). "CRS-700" manufactured by K.K.) resolution (ratio of output at 420FRPI and 210FRPI)
Evaluated by Squareness ratio is 0.8 or more, resolution is 8
0% or more was considered good. Table 1 shows the evaluation results of Examples 1 and 2 and Comparative Example 1.

[0035]

[Table 1]

[0036]

[Effect] According to the present invention, the information recording medium can be arbitrarily formed, and the information is recorded by a special method such as a difference in reflectance of infrared rays. By holding the "false judgment information", it was possible to realize an information recording medium having extremely high security and good electromagnetic conversion characteristics of magnetic recording.

[Brief description of drawings]

FIG. 1 is a sectional view of a prepaid card using the present invention.

FIG. 2 is a cross-sectional view of a print pattern when “authenticity determination information” is recorded in a barcode on a prepaid card using the present invention.

[Explanation of symbols]

 1 Support 2 Magnetic Layer 3 Thermal Destruction Printing Layer 4 Concealment Layer 5 Protective Layer 6 Bar Code Pattern Showing "Authenticity Judgment Information"

Claims (1)

[Claims] 1. A (1) magnetic layer containing an infrared absorbent, (2) a thermal destruction printing layer comprising a metal thin film layer on a support,
(3) In an information recording medium in which a concealing layer that is transparent in the infrared region and opaque in the visible region is sequentially laminated, the surface roughness of the support has a center line average roughness (Ra) of 1.2 μm. An information recording medium characterized by the following.