JPS63133321A - magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve a security performance with extremely simple constitution by combining and disposing a high coercive force pattern and low coercive force pattern in correspondence to information. CONSTITUTION:The printing pattern 2 of the high coercive force material, the printing pattern 3 of the low coercive force material and the dummy printing pattern 4 of a nonmagnetic material are combined and disposed according to recording contents on a base material 1 of a card. Residual magnetization is generated in the high coercive force pattern 2 but the low coercive force pattern 3 is the pattern where no residual magnetization is generated. The residual magnetization is, therefore, generated only in the pattern 2 and is not detectable in the low coercive force pattern 3 even if the information such as, for example, a code for deciding true or false is attempted to be read by a magnet viewer. The security is thus improved even if the recording layer is not subjected to a special processing such as demagnetization.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to magnetic recording media, and particularly to improving security.

INDUSTRIAL APPLICABILITY The present invention is applied to magnetic recording media, such as magnetic cards, which require a function to prevent unauthorized use and a function to prevent forgery and tampering.

[Prior Art] Conventionally, a method has been adopted in which a code for determining authenticity is formed on a part of a magnetic card, and the code is read by a magnetic head to determine authenticity and improve the security of the card. ing.

In conventional magnetic cards, such a code for determining authenticity is formed by a magnetic print pattern and a non-magnetic dummy print pattern, so that the code cannot be easily read. The material for magnetic printing patterns is magnetite (
Fe304) and magmuhemite (γ-Fe2O3)':
! A high coercive force material of P is used.

[Problems to be Solved by the Invention] However, in the conventional magnetic recording medium described in Section 2, when an external magnetic field is applied to read the authenticity determination code, residual magnetization occurs in the magnetic printing pattern, resulting in reprinting. If Magnetic Pure was used, there was a problem in that it became possible to visually check the authenticity determination code.

If this problem were to be solved, it would be necessary to demagnetize each time after applying an external magnetic field for reading, etc., which would complicate the system.

The present invention is intended to solve the above-mentioned conventional problems, and its purpose is to provide a magnetic recording medium with a compact structure and high security.

[Means for Solving the Problems] The magnetic recording medium according to the present invention is characterized in that at least a high coercive force pattern and a low coercive force pattern are combined in correspondence with information.

[Function] The above-mentioned high coercive force pattern is a pattern in which residual magnetization may occur, and the low coercive force pattern is a pattern in which residual magnetization does not occur.

In such a configuration, even if an external magnetic field is applied to read information, residual magnetization occurs only in the high coercive force pattern. Therefore, even if an attempt is made to decipher information such as truth/false/regularity using a magnet pure or the like, a low coercive force pattern cannot be detected. Therefore, security can be increased with an extremely simple configuration without special processing such as demagnetization.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an embodiment of a magnetic recording medium according to the present invention.

In the figure, on a base material 1 of card 7, a printed pattern 2 of a high coercive force material 1, a printed pattern 3 of a low coercive force material, and a dummy printed pattern 4 of a non-magnetic material are arranged in combinations corresponding to the recorded contents. has been done.

Examples of high coercive force materials include B a Fe12019,
y-Fe203, Co-y-Fe203,
There is Fe304 etc. Examples of low coercive force materials include Fe, Sendust alloy, M n -Z n 7. Light, Ni
-Zn ferrite, Cu-Zn ferrite, etc.

The base material 1 may be paper, a synthetic resin film, or the like, and may have a magnetic recording layer formed on its surface.

FIG. 2 is an explanatory diagram of the reading method of this embodiment. First, when the card of this embodiment is inserted into the reading device, it is conveyed in the direction of arrow A, and information is read by the magnetic field.

Reading of information is performed as follows. First, a constant magnetic flux is generated in the magnetic helad 5 by direct current. The card is then conveyed in the direction of arrow A, and the magnetic pattern on the card is scanned by the magnetic head 5.

When the magnetic head 5 passes over the high coercive force pattern 2 or the low coercive force pattern 3, the magnetic head 5 causes magnetic coupling with each magnetic pattern 2 or 3, and the magnetic flux changes and the starting end of the pattern and Generates a voltage in the opposite direction at the termination. On the other hand, since no change occurs in the magnetic flux on the non-magnetic dummy pattern 4, no voltage is generated in the magnetic head 5.

Thus, as shown in FIG.
A voltage is detected from the magnetic herad 5 only when
Therefore, the recorded contents can be read.

FIG. 3 is a schematic cross-sectional view of this embodiment after application of an external magnetic field.

Since the reading scan is performed by generating magnetic flux in the magnetic hemisphere 5, residual magnetization exists only in the high coercive force pattern 2 after the scan. Therefore, the information is read by the reading device and the desired processing is performed on P:T1. .

After that, the card is taken out from the device and held by the user in the state shown in the figure.

The information on such cards cannot be read in the reprinted version of Magnet Pure. This is because Magnet Pure can detect only the high coercive force pattern 2 that has residual magnetization, and cannot detect the low coercive force pattern 3 that constitutes information together with the high coercive force pattern 2.

[Effects of the Invention] - As described in detail, the magnetic recording medium according to the present invention is composed of at least two types of magnetic patterns, and therefore is difficult to counterfeit. In addition, residual magnetization occurs only in high coercive force patterns, so even if you try to decipher information such as authenticity codes with Magnet Pure, etc., you will not be able to detect low coercive force patterns, and as a result, The information cannot be read, so security can be increased with an extremely simple configuration without special processing such as demagnetization.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment of a magnetic recording medium according to the present invention, FIG. 2 is an explanatory diagram of a reading method of the embodiment, and FIG.
FIG. 3 is a schematic cross-sectional view of the present example after application of an external magnetic field. l...Base material 2...High coercive force pattern 3...Low coercive force pattern 4...Non-magnetic dummy pattern 5...Magnetic head representative Patent attorney Seki Yamashita Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A magnetic recording medium characterized in that at least a high coercive force pattern and a low coercive force pattern are combined in correspondence with information.