JPH05197949A - Information recording medium and production thereof - Google Patents

Abstract

PURPOSE:To disable detection with an ordinary magnetic head and to prevent dishonest use by providing a magnetic recording layer on a base body, forming fine stripe ruggedness in partially different directions on the surface of the layer and providing a nonmagnetic thin film thereon. CONSTITUTION:The magnetic recording layer 2 is provided on the base body 1 and the region A having the fine stripe ruggedness is formed in the partially different directions on the surface of the recording layer 2. The nonmagnetic thin film 3 is provided thereon. The magnetic orientation direction of a magnetic coating material is partially changed by a magnetic field means while the material has a flow property and thereafter the coating is dried at the time of applying the magnetic coating material on the substrate 1, by which the region B having the fine stripe ruggedness in the directions different from the directions of the region A is formed. The nonmagnetic thin film is formed thereon. Thus, the fixed cords formed on the information recording medium cannot be detected by the ordinary magnetic head and, therefore, the recording medium is effective for preventing the dishonest use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, and more particularly to an information recording medium excellent in forgery prevention and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, information recording media, particularly in the form of magnetic cards, are increasingly used in place of small bills. Along with this, it is necessary to take measures to prevent unauthorized use such as information alteration and card forgery. Therefore, various fraud prevention measures have been proposed. As an example of using a magnetic bar code as a fixed code, Japanese Unexamined Patent Publication No. 48-47723 "Credit Card", a card having a unique detecting means (a plurality of magnetic regions having different magnetic characteristics) in addition to a magnetic track, 118800 "Counterfeiting prevention ticket" Counterfeiting prevention ticket combining magnetic bar code and non-magnetic bar code, Japanese Patent Laid-Open No. 50-23931 "Recording medium" Information such as signal coded on non-magnetic board And a recording medium characterized by being recorded by a paint containing a component having a magnetic characteristic and having a different amount of reflection of light. JP-A-62-145585 "Magnetic information recording card" Magnetic recording at a specific position on a magnetic recording layer. There has been proposed a magnetic information recording body in which a specific code is formed of a minute magnetic material having a squareness ratio smaller than Hc of the recording layer and a concealing layer is provided on the entire surface.
As another means, in Japanese Patent Laid-Open No. 63-9016 "Information recording medium and its manufacturing method", a magnetic recording medium having a magnetic layer provided on a base made of a non-magnetic material is used. Most of the magnetic layer is oriented so as to be biased in a direction at a predetermined angle with respect to the coating direction of the magnetic layer, and a part of the magnetic layer has a certain angle with respect to the above-mentioned orientation direction and has a disordered orientation. Means such as a characteristic magnetic recording medium are disclosed.

[0003]

The above-mentioned prior art aims at preventing counterfeiting and tampering of a card, but the fixed code () formed by a magnetic bar code formed on the card is an ordinary magnetic head. Since it can detect code information, it cannot be said to be sufficient for preventing unauthorized use. In addition, there is a drawback that the portion where the magnetic bar code is formed protrudes to the surface of the medium and tilts when the magnetic cards are stacked. Further, when the variable information is written on the magnetic bar code, there is a drawback that the output waveform changes in level. In the other case, there is no drawback that the portion where the magnetic bar code is formed protrudes on the surface of the medium and causes an inclination when a magnetic card is piled up, but when variable information is written in the fixed code portion, an output waveform level fluctuation occurs. There are drawbacks. The present invention has been made to solve these drawbacks.

[0004]

That is, according to the present invention, a magnetic recording layer is provided on a substrate, and fine streaky unevenness is formed on the surface of the magnetic recording layer in partially different directions. Provided is an information recording medium characterized in that a non-magnetic thin film is provided on the. Further, according to the present invention, when a magnetic coating is applied on a substrate to form a magnetic recording layer, the magnetic recording layer is partially dried while the magnetic coating is fluid and then dried to form the magnetic recording layer. Provided is a method for manufacturing an information recording medium, which comprises forming and forming a nonmagnetic thin film on the magnetic recording layer. The present invention further forms a magnetic recording layer by applying a magnetic coating material on a substrate, and fine streaky unevenness is formed on the magnetic recording layer in different directions by magnetic field means.
Further provided is a method for manufacturing an information recording medium, which is characterized by forming a non-magnetic thin film thereon.

[0005]

In the information recording medium manufactured by the above means, the fine stripe-shaped irregularities formed on the surface of the magnetic recording layer in different directions are large depending on the measuring direction of the reflectance of the surface of the non-magnetic thin film. By causing a change and detecting it by the optical measuring means, it becomes possible to detect it as a code signal peculiar to the medium. Further, since the fine unevenness generated on the surface of the medium is 1 μm or less, when the variable information signal is written in the magnetic recording layer, the output waveform of the reproduction signal is not adversely affected.

[0006]

1 and 2 show an embodiment (magnetic card) of an information recording medium according to the present invention. That is, a magnetic recording layer 2 is provided on a base body (1), and an area A having a fine unevenness in a specific direction on its surface and an area having a fine unevenness in a partially different direction from the area A. Form B. This latter area B can be recorded according to a fixed code. A nonmagnetic layer 3 is further formed on the surface of the magnetic recording layer 2 having the regions A and B.

The fine unevenness lines on the surface of the magnetic recording layer 2 can be formed by any method such as mechanical polishing, magnetic orientation, and formation of an indentation by a pressure plate. The light reflectance of the formed non-magnetic layer is in the region A,
It is important to form directional streaks that differ corresponding to B. Although it is desirable to form the fine uneven lines in the regions A and B by changing the direction, it may be possible to obtain a sufficient effect even if one of the lines is omitted.

One method for achieving this is to apply a magnetic coating on the substrate 1 to form a magnetic layer, and while the magnetic coating is fluid, the magnetic field is oriented in the direction of +45 degrees as shown in FIG. As shown in FIG. 1 is formed in a portion which is to be an area B and then has an area A having fine uneven lines extending in the same direction.
The magnetic recording layer 2 is formed by changing the magnetic orientation in the direction of 45 degrees and then dried to finally form the non-magnetic thin film 3 on the magnetic recording layer 2.

Another method is to apply a magnetic coating on the substrate 1 and dry it to form the magnetic recording layer 2, and polish the magnetic recording layer 2 in different directions partially by mechanical means such as pressing.
Fine line-shaped irregularities having different directions are formed to form different regions A and B, and the nonmagnetic thin film 3 is further formed thereon.

Examples of the material of the component that can be used in the present invention include the following. (1) Substrate: PET, PVC, paper, metal, alloy. (2) Magnetic powder of magnetic recording layer: γFe ₂ O ₃ , Co-containing Fe ₂ O ₃ , Fe ₃ O ₄ , BaO.6Fe ₂ O ₃ , Sr
O · 6Fe ₂ O ₃ , Fe, Co-Fe, Fe-Co, F
e-Ni-Co. (3) Binder resin: A known thermoplastic, thermosetting, or electron beam curable resin such as a vinyl chloride-vinyl acetate-vinyl alcohol copolymer or polyurethane. (4) Non-magnetic thin film: Te, Sn, In, Al, Bi, P
b, Zn, Cr, Mo or alloys thereof. Next, a specific example will be described.

Example 1 A magnetic card was manufactured according to FIG. A magnetic coating prepared by dispersing barium ferrite in a PVAC binder resin was applied to one surface of a PET base having a thickness of 188 μm using a knife coater. Before the magnetic coating material loses its fluidity, the entire magnetic field is oriented in the direction of +45 degrees with respect to the longitudinal direction to form the region A, and then the magnetic coating material loses its fluidity, A magnetic field was partially oriented in the direction of 45 degrees to form a region B and then dried to form a magnetic layer composed of regions A and B having different magnetic field orientations partially. Further, Sn was formed to a thickness of about 1000Å on the magnetic layer by a vacuum vapor deposition method to manufacture an information recording medium. When light was applied to the surface of the non-magnetic layer of this recording medium from a direction of +45 degrees with respect to the longitudinal direction, a result of about 90% in A and about 7% in B was obtained as shown in FIG. For reference, the reflectance when the incident direction of light is gradually changed from the magnetic field orientation direction is also plotted in FIG. The measurement was performed using a Macbeth print contrast meter PCM-II (trade name), 3050
It was performed by irradiating a light beam having a diameter of 0.2 mm at 45 degrees at 45 °.

A magnetic coating prepared by dispersing barium ferrite in a PVAC binder resin was applied to one surface of a PET base having a thickness of 188 μm by a knife coater and dried. Next, an indentation was made by partially changing the direction on a specific portion of the surface of the magnetic layer using a printing plate having a stripe pattern with a depth of 1 μm.
Further, similarly to Example 1, Sn was formed to a thickness of about 1000Å to prepare an information recording medium. When this medium was used to measure the light reflectances of two regions having different indentation directions from a certain direction, the light reflectances were significantly different, and they could be used for recording a fixed code.

[0013]

The present invention has the following effects. (1) Since the fixed code formed on the information recording medium cannot be detected by a normal magnetic head, it is effective in preventing unauthorized use. (2) Since there is no partial protrusion as in the case of forming a magnetic bar code, it is possible to prevent an inclination when a large number of cards are piled up and a trouble of conveying the cards in the issuing machine. (3) When variable information is written on the magnetic recording layer from above the fixed code, there is no drawback that the output waveform changes in level. (4) Since variable information can be recorded even in the portion where the fixed code is recorded, the amount of information that can be recorded in the medium can be increased.

[Brief description of drawings]

FIG. 1 is a plan view of an information recording medium of the present invention.

2 is a cross-sectional view taken along the line AA of the information recording medium of FIG.

FIG. 3 is a graph showing light reflection characteristics of the information recording medium of Example 1.

[Explanation of symbols]

1 Base 2 Magnetic Recording Layer 3 Non-Magnetic Layer A Region with Specific Fine Streaky Roughness B Region with Fine Streaky Roughness in Different Direction from Region A

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G11B 5/845 Z 7303-5D 19/04 S 7525-5D

Claims (3)

[Claims] 1. A magnetic recording layer is provided on a substrate, fine streaky unevenness is formed in different directions on the surface of the magnetic recording layer, and a nonmagnetic thin film is further provided thereon. And an information recording medium. 2. A magnetic recording layer is formed by coating a magnetic coating on a substrate to form a magnetic recording layer by partially changing the magnetic orientation direction while the magnetic coating is fluid. Then, a method for manufacturing an information recording medium, comprising forming a non-magnetic thin film on the magnetic recording layer. 3. A magnetic coating is applied on a substrate to form a magnetic recording layer, and fine linear unevenness is formed on the magnetic recording layer in different directions by mechanical means. A method for manufacturing an information recording medium, which comprises forming a non-magnetic thin film on the top.