JPH03241520A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enable writing with various kinds of magnetic heads and to prevent theft or forging of data by using at least two kinds of magnetic particles having different particle sizes to form a magnetic layer on a substrate surface. CONSTITUTION:The magnetic layer 2 consists of a mixture of magnetic particles 21 of large particle size and magnetic particles 22 of small particle size. When a magnetic head (A) having a gap width suitable for the magnetic particles 21 is used to apply a magnetic field on this layer, both of particles 21 and 22 are magnetized. On the other hand, when a magnetic head (B) having a gap width suitable for the magnetic particles 22 is used, only the magnetic particles 22 are magnetized while the magnetic particles 21 are not magnetized. Therefore, two kinds of different data can be written in one magnetic layer 2 and the recorded data can not be written in one magnetic layer 2 and the recorded data can not be completely read out without reparing all of the magnetic heads applicable for respective magnetic particles. This prevents theft or forging of the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium including a magnetic layer formed of a plurality of types of magnetic particles.

[Prior Art] Conventionally, magnetic recording media such as magnetic cards and magnetic disks that magnetically record data have been provided with a magnetic layer composed of magnetic particles of a certain size.

Then, data is recorded by magnetically writing signals into the magnetic layer using a magnetic head having a gap matching the size of the magnetic particles. Also, data recorded on the magnetic layer was read.

[Problems to be Solved by the Invention] However, since the magnetic recording medium described above records data magnetically, it is easy to read and write data, and there is a risk that the data may be stolen or forged. there were.

Furthermore, since data can only be read and written by a magnetic head that is compatible with the magnetic particles in the magnetic layer, there is a drawback that it cannot be used with multiple read/write devices using different types of magnetic heads.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a magnetic recording medium that can write magnetic data compatible with a plurality of types of magnetic heads and that can prevent data theft and forgery.

[Means for Solving the Problems J] In order to achieve the above object, the present invention provides a magnetic recording medium comprising a base material and a magnetic layer provided on the surface of the base material for magnetically writing data. The magnetic layer is characterized by being formed of at least two types of magnetic particles having different sizes.

The invention set forth in item 2 is characterized in that, in the invention set forth in item 1, when data is written in the magnetic layer, the direction of magnetism of the magnetic particles is made different for each magnetic particle.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing a magnetic recording medium according to an embodiment of the present invention.

The magnetic recording medium of this example consists of a base material 1 and a magnetic layer 2. Further, a protective layer 3 for protecting the magnetic layer 2 is usually provided on the surface of the magnetic layer 2 .

The base material 1 is made of a material that does not affect magnetism, such as resin or paper. Further, depending on the use of the magnetic recording medium, it can take various shapes such as a card shape as shown in the figure, a disk shape, and a tape shape.

The magnetism M2 is provided over the entire surface of one side of the base material 1. This magnetic layer 2 may be provided in a band shape on a part of the base material l. As shown in FIG. 2, the magnetic M2 is formed by mixing large-diameter magnetic particles 21 and small-diameter magnetic particles 22.

As a result, when a magnetic field is applied to the magnetic layer 2 by a magnetic field A having a cap size adapted to the size of the magnetic particles 21 as shown, both of the magnetic particles 21 and 22 are magnetized. On the other hand, if a magnetic field is applied to the magnetic layer 2 using a magnetic field B having a gap size adapted to the size of the magnetic particles 22, the magnetic particles 21 will not be magnetized and only the magnetic particles 22 will be magnetized. Become. Therefore, by writing data into the magnetic layer 2 with the magnetic head A and then writing data with the magnetic head B, different data can be written twice into the same magnetic layer 2. Become.

Also, when reading data, the magnetic head A can only read data recorded on the magnetic particles 21, and the magnetic head B can only read data recorded on the magnetic particles 22. duality is ensured.

Furthermore, when data is written by magnetic head B, data is written with the direction of the gap set at a different angle from that of magnetic head A, thereby making the magnetic directions of the magnetic particles 21 and 22 different from each other. be able to.

Note that in this embodiment, there are two types of magnetic particles forming the magnetic layer 2, but it goes without saying that there is no need to limit the number of types to this.

[Effects of the Invention] As explained above, in the magnetic recording medium of the present invention, since the magnetic layer is formed of at least two types of magnetic particles having different sizes, different data can be recorded for each magnetic particle. Furthermore, since data is read separately for each magnetic particle, it is possible to support a plurality of read/write devices with different magnetic heads.

In addition, if all the data from each magnetic particle is combined to form one piece of information, complete information cannot be obtained unless all magnetic heads that are compatible with each magnetic particle are available, which can lead to data theft and forgery. It has the effect of preventing

In the invention described in item 2, when writing data in the magnetic layer, the magnetic direction of the magnetic particles is made different for each magnetic particle, so that in order to read all the data, a magnetic head that is compatible with each magnetic particle is used. In addition to having everything in place, the magnetic direction of each magnetic particle must be aligned, which is more effective in preventing data theft and forgery.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of the magnetic layer shown in FIG. 1. l: Base material 2: Magnetic layer 21.22 = Magnetic particles A, B: Magnetic head

Claims (2)

[Claims] (1) In a magnetic recording medium consisting of a base material and a magnetic layer provided on the surface of the base material for magnetically writing data, the magnetic layer is formed of at least two types of magnetic particles of different sizes. A magnetic recording medium characterized by: (2) The magnetic recording medium according to claim 1, characterized in that when data is written in the magnetic layer, the direction of magnetism of each magnetic particle is made different for each magnetic particle.