JPH11154306A - Magnetic head and magnetic recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable realizing a magnetic record which is hard to forge by forming a magnetic shield plate by opposing magnetic plates of almost C type and making a gap between them, and varying timing of a magnetic recording current for each track magnetic head of both sides of a magnetic shield plate. SOLUTION: A shield plate 41 is arranged between write-side magnetic cores 1a and 1b on which wires 2a are wound, stored in a magnetic core holding frame 3a, a shield plate 41 is arranged between read-side magnetic cores 1c and 1d in which magnetic cores 11 are laminated at both sides of a magnetic core 1 on which wires 2b are wound, and stored in a magnetic core holding frame 3b. A magnetic gap material 5 is placed between the write-side magnetic cores 1a, 1b and the read-side magnetic cores 1c, 1d and they are assembled, mold resin is filled in an internal space, and a 2-track combination magnetic head is formed. Magnetic recording is performed for a magnetic medium through a gap part by forming the shield plate in a C letter type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic head and a magnetic recording method used for a magnetic card reader and the like, and more particularly to a magnetic head and a magnetic recording method used in a field requiring high-security magnetic recording.

[0002]

2. Description of the Related Art Cash cards, prepaid cards,
With the spread of magnetic cards such as credit cards, counterfeit cards and the like have increased, and this has become a social problem. At present, as a countermeasure against forgery, improvements in the structure of a magnetic head, a recording signal system, and the like are being made.

FIG. 6 is an exploded perspective view of a conventionally used two-track combination magnetic head.

[0004] As shown in FIG. 6, a conventional magnetic head includes:
A substantially C-shaped write-side magnetic core 1 on which a winding 2a is applied in advance
a, 1b and a rectangular shield plate 4 housed in a groove formed in the magnetic core holding frame 3a,
The magnetic cores 11 are provided on both sides of the substantially C-shaped magnetic core 1 provided with
The magnetic core material 1c, 1d and the shield plate 4 housed in a groove formed in the magnetic core holding frame 3b are connected to the two screws 6 with the magnetic gap material 5 interposed therebetween.
Then, the mold resin is filled in the inside from the direction of arrow a and assembled.

Thereafter, as shown in FIG. 2, the gap 7 of the magnetic head is polished in an arc shape to the magnetic cores 1a, 1b, 1c and 1d to complete the magnetic head 8.

The shield plate 4 of this conventional magnetic head is
It is provided only for magnetic shielding so that the magnetic field generated by the winding of the magnetic core does not leak to the magnetic core of another adjacent track. That is, in the shield plate of the conventional magnetic head, the magnetic flux is not concentrated because the shield plate in the gap portion is not narrowed down, and the amount of magnetic flux leaking from the gap portion of the shield plate to the card sliding surface is extremely small. Magnetic recording is not possible.

[0007]

In order to increase the amount of information to be recorded and to make it difficult to forge, there is a demand for increasing the number of tracks in the same shape with respect to the conventional magnetic head.

However, the improvement in increasing the number of tracks of the magnetic head increases the unit price of the head.
Further, in the magnetic recording using a magnetic head in which the number of tracks is simply increased, there is a problem that when the magnetic head is stolen, there is a risk that a forged card is made by using the magnetic head.

Accordingly, an object of the present invention is to provide a magnetic head and a magnetic recording method capable of performing magnetic recording with high security without changing the appearance and price of a conventional magnetic head.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a multi-track magnetic head which enables magnetic recording with a shield plate by improving the shape of a shield plate used only for magnetic shielding. By applying a special magnetic recording current to the magnetic recording medium, magnetic recording that is difficult to forge can be performed.

That is, according to the present invention, in a magnetic head having two or more tracks formed by butting a pair of magnetic core holding frames accommodating a shield plate between magnetic cores with a magnetic gap material interposed therebetween, the shield plate is substantially C-shaped. This is a magnetic head having a shape of a magnetic plate.

Further, the present invention is a magnetic recording method for magnetically recording a current flowing through a winding of a magnetic core of each track of the magnetic head on a magnetic medium while adjusting or intentionally changing an energizing timing. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a two-track combination magnetic head according to an embodiment of the present invention.
In the present embodiment, except that the shape of the magnetic shield plate is a substantially C-shaped shield plate 41, it is the same as the conventional product, and a detailed description is omitted.

After assembling the components shown in FIG. 1, the magnetic head of the present invention is finished as shown in FIG. 2 by polishing the gap 7 to an arc shape up to the magnetic core.

FIG. 3 is a diagram showing the flow of magnetic flux during magnetic recording by the shield plate 41 of the two-track combination magnetic head of the present invention. In FIG. 3, the track interval is set large for easy explanation, but actually, the track is adjacent to each other.

In FIG. 3, a magnetic core 1a, a magnetic core 1
When a current flows through each of the windings 2a of b, a magnetic flux φ1 flows through each of the magnetic cores. At this time, the magnetic flux leaked from each winding 2a is applied to the shield plate 41 of the present invention.
Magnetic flux φ2 is induced.

In the case of the magnetic head of the present invention, since the gap 7 is formed in the shield plate 41 and the shield plate in the gap 7 is narrowed, the shields concentrated near the gap are formed. Plate magnetic flux φ2
Leaks to the card sliding surface like the magnetic flux φ3.

At this time, if the magnetic card is on the gap 7 of the magnetic head, magnetic recording is performed by the shield plate 41. Therefore, the shield plate 41 of the magnetic head of the present invention
In the magnetic recording in the above, the magnetization direction and strength are determined by the direction of the current flowing through the magnetic core 1a and the magnetic core 1b.

In the magnetic head of the present invention, since the magnetic signal portion recorded by the shield plate 41 cannot be reproduced by the shield plate 41, another read-only magnetic head is required. In the case of the magnetic head of the present invention shown in FIG. 1, each track composed of the magnetic cores 1a, 1c and 1b, 1d is a write / read track, and the portion of the shield plate 41 is dedicated to writing.

It is necessary to combine a read-only head with another position of the card reader corresponding to the write-only track, thereby making it possible to construct a highly secure magnetic recording system.

The reason why the magnetic head of the present invention has high security is that even if the magnetic head is stolen, the magnetic recording method is complicated, the reproduction of the magnetic recording state is complicated, and the analysis of the magnetic recording method is very difficult. Because it is difficult. less than,
An example of the magnetic recording method will be described.

FIG. 4 is a schematic diagram showing a recording state of a magnetic card on which magnetic recording has been performed by the magnetic head according to the embodiment of the present invention. 4, part A of the magnetic card 9 is a medium part having a high coercive force, part B is a medium part having a low coercive force, and the signal part recorded by the shield plate 41 (see FIG. 1) is
Part A.

In the magnetic recording on the part A, a large current
The magnetic recording is performed by the shield plate 41 while flowing through the windings of the magnetic cores 1a and 1b of the magnetic head shown in FIG. The magnetic recording of the portion A is performed by adjusting or intentionally changing the current application timing of each winding. Therefore,
It is possible to arbitrarily change the waveform shape when reproducing with a read-only head.

Next, the magnetic recording in the portion B of the low coercive force medium portion is performed by passing a small current through the windings of the magnetic cores 1a and 1b. At this time, the portion A of the high coercivity medium portion is not overwritten.

FIG. 5 is a comparison diagram of a waveform shape at the time of reproduction in general magnetic recording and an irregular waveform shape by the magnetic recording of the present invention. FIG. 5A shows a normal waveform shape, and FIG. 5B shows an irregular reproduced waveform shape by magnetic recording according to the present invention. By recognizing the irregular waveform shape shown in FIG. 5B, it is possible to recognize a regular card and a counterfeit card. In addition, it is possible to further enhance security by making a punch hole in the recording section of the section A.

Further, by comparing the irregularly reproduced waveform of the portion magnetically recorded in the portion A with the reproduced waveform of the track in the portion B, higher security magnetic recording becomes possible.

[0028]

As described above, according to the present invention, according to the present invention, the magnetic shield plate is formed into a shape having a gap in the shape of an opening formed by abutting a substantially C-shaped shield plate, and the timing of energizing the magnetic core is changed. A magnetic head and a magnetic recording method capable of performing high-security magnetic recording can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic head according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a magnetic head.

FIG. 3 is a diagram showing a flow of a magnetic flux of the magnetic head according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing a recording state of a magnetic card on which magnetic recording has been performed by the magnetic head according to the embodiment of the present invention;

FIG. 5 is a comparison diagram of a normal reproduction waveform shape and an irregular reproduction waveform shape.

FIG. 6 is an exploded perspective view of a conventional magnetic head.

[Explanation of symbols]

 1,11 Magnetic core 1a, 1b (Write side) Magnetic core 1c, 1d (Read side) Magnetic core 2a, 2b Winding 3a, 3b Magnetic core holding frame 4 Shield plate 41 Shield plate (substantially C-shaped magnetic plate) 5 Gap material 6 Tightening screw 7 Gap 8 Magnetic head 9 Magnetic card a Arrow (mold resin filling direction) φ1, φ2, φ3 Magnetic flux

Claims (2)

[Claims] 1. A multi-track magnetic head in which a pair of magnetic core holding frames accommodating a shield plate between magnetic cores are abutted with a magnetic gap material interposed therebetween, wherein the shield plate is formed of a substantially C-shaped magnetic plate. A magnetic head. 2. The magnetic recording according to claim 1, wherein a current flowing through a winding of a magnetic core of each track of the magnetic head is magnetically recorded on a magnetic medium while adjusting or changing the current application timing. Method.