JPH03224106A - Magnetic transfer type magnetic recorder - Google Patents

Abstract

PURPOSE:To make a counterfeit and falsification difficult with a simple and inexpensive device by energizing a magnetic head under the state of approaching a magnetic layer of a magnetic recording medium and the state of separating it with a positive and negative pulse current. CONSTITUTION:This recorder is provided with a magnetic recording means for performing the magnetic recording by energizing the magnetic head with the positive and negative pulse current for magnetic recording under the state of the magnetic head 2 comparatively close to the magnetic layer 11 of the magnetic recording medium 1, and a magnetic transfer means for performing the magnetic transfer by energizing the magnetic head 2 with the positive and negative pulse current in the similar manner to the above positive and negative pulse current under the state of the magnetic head 2 comparatively apart from the magnetic layer 11 of the magnetic recording medium 1. That is, under the state of magnetic gap 3 (3') of the magnetic head 2 (2') is separated from the magnetic layer 11 of the magnetic recording medium 1 two times or more as long as the length of the magnetic gap, the positive and negative pulse current that can be generated in a magnetic recording circuit is impressed on this magnetic head, and magnetic information recorded in the magnetic layer 12 of high coercive force of the magnetic recording medium can be transferred to the magnetic layer 13 of low coercive force. By this method, the device constitution is simplified, and the counter feit and falsification, etc., are difficult to execute.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording device used in a prepaid card system and the like, and particularly to a magnetic transfer type magnetic recording device.

2. Description of the Related Art Conventional magnetic transfer type magnetic recording devices of this type have
As disclosed in Japanese Patent No. 3-34727, an alternating current for generating an alternating magnetic field is applied to a magnetic head dedicated to magnetic transfer, a solenoid coil, etc. whose magnetic gap shape is different from that of a magnetic head for magnetic recording/reproduction. By magnetically transferring the magnetic information recorded in the high coercive force magnetic layer of the magnetic recording medium to the low coercive force magnetic layer, counterfeiting and tampering are made difficult.

Problems to be Solved by the Invention However, such conventional magnetic transfer type magnetic recording devices require an alternating current circuit for magnetic transfer, a special magnetic head exclusively for magnetic transfer, etc. This made it more complicated and more expensive.

An object of the present invention is to solve these conventional problems and provide a simple and inexpensive magnetic transfer type magnetic recording device.

Means for Solving the Problems According to the present invention, a magnetic recording medium having a magnetic layer having a high coercive force layer portion having a relatively high coercive force and a low coercive force layer portion having a relatively low coercive force. In a magnetic transfer type magnetic recording device for recording, the magnetic head is energized with positive and negative pulse currents for magnetic recording while the magnetic head is brought relatively close to the magnetic layer of the magnetic recording medium. A magnetic recording means for performing magnetic recording and a magnetic head are attached to the magnetic head with positive and negative pulse currents similar to the positive and negative pulse currents in a state where the magnetic head is relatively separated from the magnetic layer of the magnetic recording medium. The present invention is characterized by comprising a magnetic transfer means for performing magnetic transfer by applying force.

Embodiments Next, the present invention will be described in more detail with reference to embodiments of the present invention based on the accompanying drawings.

FIG. 1 schematically shows the relationship between a magnetic recording medium and a magnetic head in a magnetic transfer type magnetic recording device as an embodiment of the present invention. As shown in FIG. 1, the magnetic recording medium 1 is in the shape of a magnetic card, and includes a substrate 10 made of, for example, polyethylene terephthalate with a thickness of about 188 μm, and a substrate 10 with a high coercive force of about 27500 e and a thickness of about 6 μm. Approximately 12 μm with magnetic layer 12 and low coercive force of approximately 2700e
a magnetic layer 10 consisting of two layers, a magnetic layer 13 having a thickness of approximately 2.
The protective layer 14 has a thickness of μm. This magnetic recording apparatus mainly includes a magnetic head 2 for magnetic transfer with a magnetic gap length of about 50 μm, and a magnetic head 2' for magnetic recording and reproduction with a magnetic gap length of about 50 μm. The magnetic head 2 has a magnetic gap 3, and the magnetic head 2' has a magnetic gap 3'. In addition, the magnetic head 2
is fixed to the lower end of a shaft 4, and is supported by a magnetic head support 5 via this shaft 4, a spring 6, and a fixing plate 7. On the other hand, the magnetic head 2' is mounted on a magnetic head fixing base 4.
’ is fixed. The magnetic head 2 for magnetic transfer and the magnetic head 2' for magnetic recording/reproduction are arranged to face each other with the magnetic recording medium 1 in between. 10, the magnetic head 2' is pressed against the protective layer 14 of the magnetic recording medium 1.

Note that the magnetic gap shapes of the magnetic head 2 and the magnetic head 2' are the same.

FIG. 2 is a diagram showing the magnetization state of a magnetic transfer type magnetic recording medium used in an embodiment of the magnetic transfer type magnetic recording device according to the present invention, and arrows indicate the direction of magnetization. Figure 2 (a
) shows the magnetization state when information is magnetically recorded on the magnetic recording medium 1 by applying positive and negative pulse currents generated by a magnetic recording circuit to the magnetic head 2'. Figure 2(b)
shows the magnetization state when the magnetization recorded in the high coercive force magnetic layer 12 is magnetically transferred to the low coercive force magnetic layer 13 by applying positive and negative pulse currents to the magnetic head 2, and in this state, Almost no magnetic flux due to magnetization flows out of the magnetic recording medium 1 because a closed magnetic path is formed between the high coercive force magnetic layer 12 and the low coercive force magnetic layer 13 as shown by the broken line. FIG. 2(C) shows the magnetization state when only the low coercive force magnetic layer 13 of the magnetic recording medium 1 is DC demagnetized by applying a DC current to the magnetic head 2. FIG. The magnetic flux caused by the magnetization of the high coercive force magnetic layer 12 on which information is magnetically recorded flows out of the magnetic recording medium 1 as shown by the broken line.

FIG. 3 is a diagram showing the magnetic field distribution near the magnetic gap of the magnetic head, and H8 is the maximum magnetic field of the magnetic gap.

FIG. 4 is a diagram showing an outline of the main flow of magnetic flux from the magnetic head 20, and FIG. 4(a) shows the distance between the magnetic gap and the magnetic layer of the magnetic recording medium in FIG. The ratio y/g to the gap length is less than or equal to 0.5, and therefore,
The magnetic field at the center of the gap (x=0) is relatively strong, resulting in a flow of magnetic flux that allows magnetic recording. Figure 4(b) shows the third
77g in the figure is 2 or more, which is a flow of magnetic flux that cannot generally be used for magnetic recording. The thickness of the arrow represents the strength of the magnetic field. It can be seen from FIG. 3 that the ratio of the magnetic field at the gap center (x=0) when 77g is 2 to the magnetic field at the gap center when 77g is 0.5 is 1/3 or less.

The operation of the magnetic transfer type magnetic recording apparatus of the embodiment shown in FIG. 1 will be described with reference to FIGS. 1, 2, and 4.

When the magnetic recording medium 1 is inserted into the magnetic transfer type magnetic recording device schematically shown in FIG. 1 and moved to the magnetic gap 3' of the magnetic head 2' as shown, The distance between the magnetic gap 3' and the high coercive force magnetic layer 12 of the magnetic recording medium 1 is approximately 14 μm, which is less than 0.3 times the length of the magnetic gear lug of the magnetic head 2', which is 50 μm.
Magnetic recording can be performed by the flow of magnetic flux shown in FIG. 4(a), and by applying positive and negative pulse currents generated by a magnetic recording circuit (not shown) to the magnetic head 2',
record information. Here, when the moving speed of the magnetic recording medium 1 is about 19 cm/s and the recording density is 210 BPI using the FM recording modulation method, the IF height is 57 bps and the 2F is 3.14.
This is a positive and negative pulse current at a speed of bps. The magnetization state of the magnetic recording medium 1 at this time is as shown in FIG. 2(a). The maximum magnetic reversal length is approximately 121 μm.

Next, when the moving direction of the magnetic recording medium 1 is reversed and the substrate 10 of the magnetic recording medium 1 comes into contact with the magnetic head 2, the distance between the magnetic gap 3 and the high coercivity magnetic layer 12 of the magnetic recording medium 1 is The distance to the magnetic layer 13 having a low coercive force of about 188 μm is about 194 μm, which is more than 3.7 times the length of the magnetic gear lug of the magnetic head 2 (50 μm), so the flow of magnetic flux is similar to that shown in FIGS. When positive and negative pulse currents generated from a magnetic recording circuit and applied to the magnetic head 2 at a speed higher than the IF, the maximum value of the magnetic field applied to the magnetic layer 12 is smaller than the coercive force of the magnetic layer 12, and the magnetic field applied to the magnetic layer 13 Since the maximum value of is larger than the coercive force of the magnetic layer 13, the second
As shown in Figure (b), the magnetization of the high coercive force magnetic layer 12 is magnetically transferred to the low coercive force magnetic layer 13.

In this magnetized state, the magnetic flux due to magnetization is
Since almost no information leaks out of the magnetic head, it is not possible to reproduce the magnetically recorded information using a general magnetic head, and even if a magnetic developer such as magnetic fluid is used, the magnetic pattern of the magnetically recorded information cannot be visually observed. I can't. Therefore, forgery, falsification, etc. are extremely difficult.

To reproduce the information magnetically recorded on the magnetic recording medium 1, a direct current having a value equivalent to the peak value of the positive and negative pulse currents for magnetically recording the information is applied to the magnetic head 2 to generate a low coercive force magnetic material. It is sufficient to demagnetize the layer 13 with direct current, and the magnetic recording medium 1
The magnetization state of is as shown in FIG. 2(C).

In addition, in FIG. 1, the thickness of the high coercive force magnetic layer 12 is approximately 6 μm.
In this case, the coercive force was set to about 27500e, the thickness of the low coercive force magnetic layer 13 was set to about 12 μm, and the coercive force was set to about 2700e.
From Figure 3, the ratio of high coercive force to low coercive force is 7 (77
It is clear that it is sufficient that the value is greater than or equal to the reciprocal of the value of H, (x, y)/H, at x=0 when g is 2). In the embodiment described above, this ratio is about 10, so the design is easy and the thickness of the substrate 10 can be changed from about 188 μm to about 95 μm.
It has been confirmed that even if the magnetic recording medium is changed to a magnetic recording medium having a thickness of 0 μm, the above-described operation is performed. Also, a magnetic head 2 for magnetic transfer and a magnetic head 2' for magnetic recording and reproduction are provided.
The magnetic head for magnetic transfer is arranged so as to sandwich the magnetic recording medium 1 between the magnetic layers 1 and 1 of the magnetic recording medium.
1 and the magnetic gap for magnetic transfer is 100 μm or more (the upper limit depends on the magnitude of the positive and negative pulse currents). It may be placed on the same side as the head, that is, on the magnetic layer 11 side instead of on the substrate 10 side of the magnetic recording medium. Furthermore, although it has been explained that the magnetic layer 11 is composed of two layers, a magnetic layer with high coercive force and a magnetic layer with low coercive force, magnetic particles with high coercive force and low coercive force are dispersed to form the high coercive force layer part. It may also be a single magnetic layer having a low coercive force layer portion.

FIG. 5 is a diagram similar to FIG. 1 showing a magnetic transfer type magnetic recording device as another embodiment of the present invention. The magnetic head 30 is provided with a magnetic head 30 commonly used as a magnetic head, and further provided with a magnetic head moving means 40 for moving the magnetic head 30. The magnetic head 30 has a magnetic gap 31, and the magnetic gap length of this magnetic gap 31 is approximately 50 μm. The magnetic head moving means 40 mainly includes a fixed base 36 and a plunger magnet 33 attached to the fixed base 36.

The plunger magnet 33 has a disc-shaped armature 34 attached to a guide shaft 35.
A magnetic head 30 is fixed to 4. The guide shaft 35 is
It extends through the fixing base 36 and has the fixing plate 3 at its upper end.
It has 8. This fixing plate 38 serves to fix the return spring 37 mounted around the guide shaft 35 between it and the fixing base 36. This magnetic head moving means 40
By energizing and deenergizing the plunger magnet 33, the magnetic head 30 is moved to the magnetic gap 3.
1 is in close contact with the magnetic layer 11 of the magnetic recording medium 32 within 0.5 times the magnetic gap length, and the magnetic gap 31 is separated from the magnetic layer 11 of the magnetic recording medium 32 by more than twice the magnetic gap length. It can be moved to two positions. The moving distance of the armature 34 is the distance shown in dimensions in FIG. 5, and is, for example, 500 μm.

Next, the operation of the magnetic transfer type magnetic recording apparatus of the embodiment shown in FIG. 5 will be explained. First, in the state shown in FIG. 5, the magnetic recording medium 32 is inserted into this magnetic transfer type magnetic recording device, and the magnetic gap 3 of the magnetic head 30 is
When the magnetic recording medium 32 moves to 1, if the plunger magnet 33 remains returned by the return spring 37,
Magnetic gap 31 of magnetic head 30 and magnetic recording medium 32
The distance to the high coercive force magnetic layer 12 is about 14 μm, as in FIG.
Since it is less than 0.3 times μm, magnetic recording can be performed using the flow of magnetic flux shown in FIG. 4(a). Next, when the moving direction of the magnetic recording medium 32 is reversed and the magnetic recording medium 32 has moved into the magnetic gap 31 of the magnetic head 30, when a current is applied to the plunger magnet 33 to energize it, the magnetic head 30 The armature 34 to which is fixed moves approximately 500 μm, and the distance between the magnetic gap 31 of the magnetic head 30 and the high coercive force magnetic layer 12 of the magnetic recording medium 32 is approximately 514 μm, and the distance to the low coercive force magnetic layer 13 is approximately 514 μm. The length is approximately 502 μm, which is more than 10 times the length of the magnetic gear tooth of the magnetic head 30, which is 50 μm, so the magnetic flux flow is as shown in FIG.
), the magnetization of the high coercive force magnetic layer 12 is magnetically transferred to the low coercive force magnetic layer 13. This magnetic recording medium 3
In order to reproduce the information magnetically recorded on the magnetic layer 2, the magnetic layer 13 with a low coercive force is demagnetized by direct current while applying a current to the plunger magnet 33 and keeping it energized. The magnetization state of the magnetic recording medium 32 is often shown in FIG.
The result will be as shown in C).

In FIG. 5, the moving distance of the armature 34 of the plunger magnet 33 is set in a direction perpendicular to the surface of the magnetic recording medium 32, but the present invention is not limited to this. It may be configured as shown schematically in . In the embodiment shown in FIG. 6, the same magnetic head as the magnetic head 30 shown in FIG. I have to. Therefore, by rotating the magnetic head mounting plate 50, the distance between the magnetic layer 11 of the magnetic recording medium 32 and the magnetic gap 31 of the magnetic head 30 can be changed.

Effects of the Invention As described above, according to the present invention, the magnetic gap of the magnetic head is separated from the magnetic layer of the magnetic recording medium by 2 times the magnetic gap length.
In a state where the magnetic recording circuit is more than twice as open, positive and negative pulse currents that can be generated by the magnetic recording circuit are applied to the magnetic head, and the magnetic information recorded in the high coercive force magnetic layer of the magnetic recording medium is transferred to the low coercive force magnetic layer. Since magnetic transfer is possible, there is no need for an AC circuit for magnetic transfer or a special magnetic head dedicated to magnetic transfer, which were required in the past, and the device configuration can be made simpler and cheaper. .

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a magnetic transfer type magnetic recording device as an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a magnetic transfer type magnetic recording device used in an embodiment of the magnetic transfer type magnetic recording device according to the present invention. FIG. 3 is a diagram showing the state of magnetization in a magnetic recording medium. FIG. 3 is a diagram showing the magnetic field distribution near the magnetic gap of the magnetic head. FIG. 5 is a diagram similar to FIG. 1 showing a magnetic transfer type magnetic recording device as another embodiment of the present invention, and FIG. 6 is a diagram showing a magnetic transfer type magnetic recording device as another embodiment of the present invention. FIG. 2 is a schematic diagram showing the device. 1... Magnetic recording medium, 2... Magnetic head for magnetic transfer, 2'...
Magnetic head for magnetic recording and reproduction, 3.3'...
Magnetic gap, 4...Axle, 4'...Magnetic head fixing base, 5...Magnetic head support base, 6...Spring, 7......・Fixed plate, 10... Substrate, 11... Magnetic layer, 12... Magnetic layer with high coercive force, 13... Magnetic layer with low coercive force, 14...Protective layer, 20.30...Magnetic head, 31...Magnetic gear knob, 32...Magnetic recording medium, 33... ... Plunger Makunetsu 34 ...
- Armature, 35...Guide shaft, 36...Fixing base, 37...Return spring, 38...Fixing plate, 40...・Magnetic head moving means, 50...
・Magnetic head mounting plate, 60...rotating shaft. Figure 5 r-Kiichi 1

Claims (1)

[Claims] (1) To perform magnetic recording on a magnetic recording medium having a magnetic layer having a high coercive force layer portion with a relatively high coercive force and a low coercive force layer portion with a relatively low coercive force. In the magnetic transfer type magnetic recording device, magnetic recording is performed by energizing the magnetic head with positive and negative pulse currents for magnetic recording while the magnetic head is brought relatively close to the magnetic layer of the magnetic recording medium. by energizing the magnetic head with a positive and negative pulse current similar to the positive and negative pulse current in a state where the magnetic recording means and the magnetic head are relatively separated from the magnetic layer of the magnetic recording medium. 1. A magnetic transfer type magnetic recording device comprising: magnetic transfer means for performing magnetic transfer. (2) The magnetic head of the magnetic recording means is a magnetic head for magnetic recording and reproduction in which the magnetic gap is in close contact with the magnetic layer of the magnetic recording medium within 0.5 times the magnetic gap length, and The magnetic transfer type magnetic head according to claim 1, wherein the magnetic head of the means is a magnetic head for magnetic transfer in which the magnetic gap is always separated by at least twice the magnetic gap length from the magnetic layer of the magnetic recording medium. Recording device. (3) The magnetic head of the magnetic recording means and the magnetic head of the magnetic transfer means are a common magnetic head, and the magnetic head has a magnetic gap that is equal to the magnetic gap length of the magnetic layer of the magnetic recording medium. Claim (1) wherein the magnetic gap is moved between two positions: a position where the magnetic gap is in close contact within 0.5 times, and a position where the magnetic gap is separated from the magnetic layer of the magnetic recording medium by at least twice the magnetic gap length. ) magnetic transfer type magnetic recording device.