JP3378979B2 - Magnetic recording medium and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium and a method for manufacturing the same, and more particularly, it is safe against unauthorized use such as forgery and alteration of prepaid cards, commuter passes, point cards, identification cards and the like. The present invention relates to a magnetic recording medium which is preferably used in a field such as a magnetic card which is required to have extremely high properties and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, magnetic recording media have spread rapidly, and especially for applications used for magnetic cards and the like, safety against illegal use such as forgery and alteration is becoming more important.

As a method of improving the safety, there is known a method of forming identifiable fixed information which cannot be rewritten on the magnetic recording medium itself and making a true / false judgment.

In addition, it is widely used for magnetic cards for transportation and the like, and a method of providing a magnetic bar code with a fixed pattern, and JP-A-5-318974, 7-29156, 7-29.
As described in No. 157, an arbitrary signal is recorded on the first magnetic layer, and a magnetic paint using magnetic powder is applied and dried on this.
A method for forming a non-rewritable fixed signal, JP-A-55-163443 and JP-A-7-262327, 8
As described in JP-A-185464, there is known a method in which a fibrous conductor is added at the time of forming a non-magnetic substrate, and the distribution of the conductor is pattern-recognized to obtain a fixed signal that cannot be rewritten.

[0005]

However, since the method of providing the magnetic bar code having a fixed pattern has a fixed pattern depending on the amount of bills and the like, those skilled in the magnetic recording method analyze the recorded information. There is a possibility that it can be duplicated and altered in large quantities.

Further, JP-A-5-318974, 7-2
9156, 7-29157 in the first magnetic layer,
There is a method of forming a second magnetic layer having a fixed signal that cannot be rewritten by recording an arbitrary signal and applying and drying a magnetic paint using a magnetic powder material on the signal. There is a problem that the number of patterns of fixed signals is limited because an artificial element such as setting a pattern to be recorded on the first magnetic layer is set in advance.

Further, in the methods disclosed in JP-A-55-163443, JP-A-7-262327, and 8-185464, when a non-magnetic substrate is formed, a fibrous conductor is added to distribute the distribution. It is a method to read as a fixed data by recognizing the pattern by a microsensor or an electromagnetic induction action. The randomness of the fixed data can be improved depending on the distribution of the fibrous conductor. However, there is a problem that the manufacturing method such as the dispersibility of and the reading method are complicated.

Therefore, it is an object of the present invention to further improve the randomness of a fixed signal, which is a problem of the above-mentioned method, and simply provide it.

[0009]

According to the present invention, there is provided a method of manufacturing a magnetic recording medium comprising laminating at least one kind of magnetic material powder on a non-magnetic substrate, the non-magnetic substrate being provided on the non-magnetic substrate. Obtained by applying a magnetic coating material using magnetic material powder, orienting and drying with a DC magnetic field to form the first magnetic layer, and inverting the polarity of the residual magnetization on the first magnetic layer. Magnetically recording the generated signal,
A magnetic coating material using a magnetic material powder is applied on the recorded first magnetic layer, and an orientation treatment by a DC magnetic field is performed.
A step of forming a second magnetic layer by drying,
Then, the signal magnetically recorded in the first magnetic layer is erased by a direct current or an alternating magnetic field, and then the signal obtained by reversing the polarity of the residual magnetization is magnetically recorded on the second magnetic layer. Then, a magnetic coating material using a magnetic material powder is applied on top of it, and a third magnetic layer is formed by performing orientation treatment with a DC magnetic field, drying and solidifying, and having a fixed signal that cannot be rewritten. A method of manufacturing a magnetic recording medium, characterized by comprising:

[0010]

According to the method of the present invention, a non-rewritable fixed pattern having improved randomness is formed on the first magnetic layer.

A signal obtained by reversing the polarity of the magnetization is magnetically recorded in the first magnetic layer. A magnetic paint using a magnetic powder material is applied on this, and a direct-current orientation magnetic field in a fixed direction is applied before drying. As a result, in the applied magnetic paint, the magnetic field is strengthened in the first magnetic layer in the portion where the direction of the magnetic field generated from the portion magnetized by reversing the polarity and the direction of the direct-current orientation magnetic field coincide with each other. , The magnetic fields cancel each other out and weaken in the non-coincident portions. For this reason, the magnetic paint concentrates in the areas where the magnetic fields are strengthened, and the magnetic paint is dispersed in the areas where the magnetic fields cancel each other out.

At this point, if the second magnetic layer is dried and solidified, a portion having a large amount of magnetic material and a portion having a small amount of magnetic material are formed.

Further, after the second magnetic layer is formed, a signal obtained by reversing the polarity of magnetization in the first magnetic layer is
Degauss by direct current or alternating magnetic field, then
A signal obtained by reversing the polarity of magnetization is magnetically recorded again on the second magnetic layer. After this magnetic recording,
A magnetic paint using a magnetic material powder is applied, and a DC directing magnetic field in a fixed direction is applied before drying. In this case, the direction of the DC magnetic field may be the same as that at the time of forming the second magnetic layer, or may be the opposite direction.

At this point, by drying and solidifying,
Random fixed signal obtained compared to the case where the second and third magnetic layers are directly formed without erasing / recording the fixed data on the first magnetic layer after forming the second magnetic layer. The sex can be improved.

Further, unevenness is formed on the surface in a portion where a large amount of magnetic material powder is gathered and a portion where a small amount of magnetic material powder is gathered. The unevenness is coated with a coating material using a non-magnetic material to form a protective layer, By providing the print recording layer, the surface becomes smooth and the visibility can be improved.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The principle of a method for manufacturing a magnetic recording medium according to an embodiment of the present invention will be described in detail below with reference to the drawings.

Referring to FIG. 1, the present invention is a non-magnetic substrate 1
An arbitrary signal is recorded on the first magnetic layer 16 formed on the first magnetic layer 5, and a magnetic coating material 19 using a magnetic powder material is applied onto the first magnetic layer 16 to be oriented by a DC magnetic field and dried, whereby the second magnetic layer 21 is formed. To form. Before forming the third magnetic layer 26, an arbitrary signal recorded in the first magnetic layer is converted into direct current or
It is erased by the orientation by the alternating magnetic field, and then the polarity of the residual magnetization is reversed from above the second magnetic layer 21. Thereby, the obtained signal is magnetically recorded, and a magnetic coating material using a magnetic powder material is applied, oriented by a DC magnetic field, and dried. As a result, the inventor has found that the randomness of a fixed signal that cannot be rewritten can be further improved and improved, and a manufacturing method and a reading method can be easily provided.

More specifically, the non-magnetic substrate 15 is a commonly used one such as PET film or paper. As the magnetic material powder used as the magnetic coating material for the first magnetic layer 16, Ba ferrite, Sr ferrite, CrO ₂ , Co-γFe ₂ O ₃ , γ-Fe ₂ O _{3 are used.}
Any general magnetic material powder may be used.

As the magnetic material powder used as the magnetic coating material for the second magnetic layer 21 and the third magnetic layer 26, high permeability alloys such as permalloy, sendust, amorphous, silicon steel, iron and Mn-Zn ferrite, It is a soft magnetic material typified by soft ferrite such as Ni-Zn ferrite, or a general magnetic material powder used for the first magnetic layer 16.

First, the above-mentioned magnetic material powder is dispersed in a binder or the like on the non-magnetic substrate 15 and applied as a magnetic paint, and oriented by a DC magnetic field having a strength suitable for each magnetic material powder. First by drying and solidifying
The magnetic layer 16 is formed (FIG. 1 (1)). As shown in FIG. 1B, the first magnetic layer 16 has a magnetization polarity of
The signal obtained by inverting is magnetically recorded. As shown in FIGS. 1C to 1C, the second magnetic layer 21 and the third magnetic layer 26 are formed on the first magnetic layer 16.
As shown in FIGS. 1 (7) and (8), the third magnetic layer 2
The coating material 24 of No. 6 is applied and the magnetic field 20 is applied, so that the third magnetic layer 26 is formed in a wavy shape.

Examples of the magnetic material powder used for the second magnetic layer 21 and the third magnetic layer 26 include the above-mentioned various magnetic material powders. However, since a higher output can be obtained with a larger saturation magnetization amount, a high magnetic permeability alloy is preferable.
Further, since these magnetic material powders have a low coercive force, there is an advantage that the magnetic recording pattern cannot be visually confirmed by a magnetic viewer or the like. The smaller these powder particle sizes are,
Further, as for the shape, a spherical shape is suitable because it is easy to move due to a magnetic field due to a signal magnetically recorded in the first magnetic layer 16 or a DC orientation magnetic field. The effect is recognized.

In the step of forming the second magnetic layer 21, a signal obtained by reversing the polarity of the magnetization is magnetically recorded in the first magnetic layer 16 as shown in FIG.
The magnetic material powder is dispersed in a binder or the like and applied as a magnetic paint 19, and a direct-current orientation magnetic field in a fixed direction is applied. A cross section of the situation at this time is shown in FIG.

A magnetic field 18 generated from a signal recorded in the first magnetic layer 16 and a magnetic paint 19 for forming the second magnetic layer
And the magnetic field 20 applied from the DC orientation magnetic field is
The different directions cancel each other out, weakening the magnetic field, and the magnetic fields at the a portion are strengthened because of the same direction, and the magnetic paint concentrates at the a portion. After that, the second magnetic layer 21 is formed by drying and solidifying (FIG. 1 (4)).

In the step of forming the third magnetic layer 26, the signal magnetically recorded on the first magnetic layer 16 is erased by a DC or AC magnetic field. After that, a signal obtained by reversing the polarity is magnetically recorded on the first magnetic layer 16. In this magnetic recording, the same signal recorded in the first magnetic layer 16 may be recorded, or magnetic recording may be performed by changing the recording density, the recording method, and the like.

To form the third magnetic layer 26, the magnetic material powder is dispersed in a binder or the like on the second magnetic layer 21 to apply it as the magnetic paint 24, and the DC orientation magnetic field 20 is applied. Give. The magnetic material powder used when forming the third magnetic layer 26 may be the same magnetic powder material as the second magnetic layer 21, or may be different.

Further, the direction of the DC orientation magnetic field applied does not have to be the same as the direction of the DC orientation magnetic field when the second magnetic layer 21 is formed.

In FIGS. 1 (5), 1 (6), 1 (7) and 1 (8), the magnetic coating material for the third magnetic layer 26 is provided on the second magnetic layer 21. The cross-section when applied and subjected to a DC orientation magnetic field is shown.

After forming the second magnetic layer 21, the first magnetic layer 1 is formed.
When the third magnetic layer 26 is continuously formed without erasing the fixed signal magnetically recorded in 6, the magnetic field 23 and the DC orientation magnetic field 20 generated from the first magnetic layer 16 and the second magnetic layer 21 are generated. , The magnetic field 20 when applied to the magnetic paint is b
The magnetic field for canceling each other becomes weaker in the portion a, and the magnetic paint concentrates in the portion a because the magnetic fields strengthen each other. After that, the third magnetic layer 26 is formed by drying and solidifying (FIGS. 1 (6) and 11 (1)).

After forming the second magnetic layer 21, the first magnetic layer 1 is formed.
The fixed signal magnetically recorded on 6 is erased by a direct-current or alternating-current magnetic field, and the fixed signal is magnetically recorded on the second magnetic layer 21 (FIG. 1 (5)). After magnetic recording, a cross section is shown when a magnetic coating material for the third magnetic layer 26 is applied onto the second magnetic layer 21 and a direct current magnetic field is applied (FIG. 1).
(7)). Compared with the case where the second magnetic layer 21 and the third magnetic layer 26 are continuously formed, it is possible to obtain a magnetic recording medium having fixed data with improved randomness and which cannot be rewritten (see FIG. ), FIG. 11 (2)).

The strength of the direct-current orientation magnetic field applied when the second magnetic layer 21 and the third magnetic layer 26 are formed depends on the strength of the first magnetic layer 16.
It is necessary to determine it in consideration of the coercive force of the magnetic material powder used in. If the strength of the magnetic field is too small, it will be difficult for the magnetic paint to move when the second magnetic layer 21 and the third magnetic layer 26 are formed at the portions where the magnetic fields are strengthened. The fixed data recorded in the magnetic layer 16 is attenuated. In addition, the viscosity of the magnetic paint is
Since it depends on the particle size, particle size and shape of the third magnetic material powder, it is necessary to determine the strength of the DC orientation magnetic field in consideration of these points.

As a forgery prevention method for improving safety, there is a method of making recording / reproduction of a magnetic recording medium difficult, and a magnetic layer has a multi-layered structure and a dummy is formed on a layer on which regular information is recorded. There is known a method in which a layer in which a signal is recorded or a magnetic concealing layer is provided to make reading difficult in a normal magnetic data reader.

The present invention is very effective when used in combination with these methods. An example of the magnetic recording medium when used together is shown in FIGS.

In FIG. 3, the layer 29 of the track 27 of FIG. 2 in which the dummy information is recorded on the layer 30 on which the normal information is recorded.
A cross section of is shown.

FIG. 5 shows a layer 30 in which regular information is recorded.
A cross section of a track 32 having a magnetic shielding layer 33 provided on the top is shown. The magnetic shielding layer 33 preferably contains a predetermined amount of the soft magnetic material 33-1. These are layer 3
When reading the normal information from 0, the magnetic head can read from the layer on which the dummy is recorded or the magnetic concealment layer 33. In the case of a layer in which dummy information is recorded, the thickness of these layers is such that the read output of the dummy information is sufficient, it is indistinguishable from the signal of the normal information, and further, there is sufficient disturbance in the normal signal waveform. It is necessary to have a thickness that causes

The track 32 having the magnetic shielding layer 33 is also provided.
In this case, the magnetic field generated from the signal of the normal information needs to have a thickness that cannot be read on the magnetic shielding layer 33.

By forming a protective layer (not shown) of ultraviolet curable silver ink or white ink on the third magnetic layer 26 of FIG. 1 (6), compared to the case without the protective layer. The visibility can be improved. If the protective layer becomes thicker, the read output of a fixed signal that cannot be rewritten decreases, so it is necessary to adjust the thickness to an appropriate thickness before forming.

[0037]

EXAMPLES The present invention will be described in more detail below with reference to examples.

(Example 1) As the non-magnetic substrate 15, 18
Use 8 μm PET film. First magnetic layer 16
In this method, regular information is recorded, a magnetic concealing layer is formed on the regular information, and the reading is made difficult by a magnetic viewer or the like. An example of forming a fixed signal with improved randomness that cannot be rewritten on the magnetic shielding layer is shown below.

The coating apparatus for forming the first magnetic layer 16 shown in FIG. 6 is composed of an unwinding section, a coating section, an orientation section, a drying section and a winding section. A roll-shaped 188 μm PET film 2 is set on the unwinding unit 1, and a Ba ferrite powder having a coercive force of 2750 Oe is dispersed on the PET film by the coating unit 3 in a binder such as a urethane-based and vinyl chloride-based vinyl mixed binder.・ 1 after drying the manufactured magnetic paint
Apply so that the thickness becomes 0 μm. Then, a direct-current orientation magnetic field of 4000 G is applied by the orientation unit 4, dried and solidified by the drying unit 6, and wound as a roll 8 by the winding unit 9.

The magnetic recording device for performing magnetic recording on the first magnetic layer 16 in FIG. 7 may be an independent device as shown in the drawing, or may be attached in front of the coating part of the coating device. Good. Using this device, a fixed signal is magnetically recorded on the first magnetic layer 16. The roll 8 is set on the unwinding portion 1, the magnetic head 10 (sendust core with a head gap of 45 μm) is used, and a predetermined F2F is formed on the first magnetic layer 16.
The signal of the method is magnetically recorded, and thereafter, by the winding unit 9,
It is wound up as a roll 11.

The coating apparatus for forming the recording layer of the second magnetic layer 21 shown in FIG.
This is the same as the coating apparatus for forming the magnetic layer 16. The roll 11 magnetically recorded on the first magnetic layer 16 is set on the unwinding part 1, and then the average particle diameter is 15 μm and the coercive force is 10 Oe.
Magnetic powder prepared by dispersing and manufacturing permalloy scale-like powder of No. 1 in a binder such as a mixture of urethane and acrylic.
Coating by the coating unit 3 and a maximum of 500G by the orientation unit 4
DC directing magnetic field is applied. The drying unit 6 dries and solidifies, and the winding unit 9 winds the second magnetic layer 21 into a roll 12.

FIG. 9 is a schematic diagram of an apparatus for erasing / re-recording a signal magnetically recorded on the first magnetic layer 16. This device may be an independent device as shown in FIG. 6 or may be attached in front of the coating part of the coating device. The roll 12 is set on the unwinding portion 1 and a predetermined F is fed from above the second magnetic layer 21.
The signal of the 2F system is magnetically recorded, and then wound up as a roll 13 by the winding unit 9.

FIG. 10 shows an outline of a coating apparatus for forming the third magnetic layer 26. The basic structure is the same as that of the coating apparatus for forming the first magnetic layer 16 of FIG. 6 and the second magnetic layer 21 of FIG.

The roll 13 on which the signal of the second magnetic layer 21 / F2F system is magnetically recorded is set in the unwinding portion 1, and the magnetic material powder used when forming the second magnetic layer 21 is used. The magnetic paint dispersed and manufactured is applied by the coating unit 3.
The second magnetic layer 21 and the third magnetic layer 26 are combined and dried and solidified, and then coated so that the film thickness is 10 μm, and the alignment section 4 applies a DC orientation magnetic field of up to 500 G and dried by the drying section 6. Solidify to form the third magnetic layer 26.

Through the above steps, it is possible to obtain a magnetic recording medium having a fixed signal which cannot be rewritten and has improved randomness.

A white ink containing a white pigment was formed as a protective layer (not shown) on the third magnetic layer 26 by a coating device. As a result, the surface was smoother and the visibility was improved compared to the case without the protective layer.

[0047]

According to the present invention, an arbitrary signal is magnetically recorded on the first magnetic layer, the second magnetic layer is formed thereon, and after the second magnetic layer is formed, the first magnetic layer is formed. By erasing an arbitrary signal of the magnetic layer, magnetically recording an arbitrary signal on the second magnetic layer, and applying the coating material of the third magnetic layer, the third magnetic layer is formed in a wavy shape. As a result, there is an effect that it is possible to supply a magnetic recording medium having a non-rewritable fixed signal with improved randomness.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of each intermediate product for explaining the principle of a magnetic recording medium of the present invention and a manufacturing method thereof.
FIG. 1A shows a first magnetic layer 16 on a non-magnetic substrate 15.
It is sectional drawing of the intermediate formation object which formed. Figure 1 (2) shows
FIG. 7 is a cross-sectional view of an intermediate product showing a state when a signal is recorded on the first magnetic layer 16. FIG. 1C shows the second magnetic layer 2
1 is a cross-sectional view of the intermediate product coated with the magnetic coating material 19 in order to form 1.
multiply. When the direction of the magnetic field 18 generated from the signal recorded in the first magnetic layer 16 and the direction of the DC orientation magnetic field 20 after coating are the same, the part a where the magnetic fields strengthen and the part b where the magnetic fields weaken differ from each other. it can. FIG. 1 (4) is a cross-sectional view of an intermediate product on which the second magnetic layer 21 is formed (after being dried and solidified). FIG. 1 (5) is a cross-sectional view of the intermediate product showing a state in which the signal of the first magnetic layer 16 is erased and rerecorded from the second magnetic layer 21. FIG. 1 (6) is a cross-sectional view of an intermediate product in which the third magnetic layer 26 is continuously formed without erasing the signal recorded in the first magnetic layer 16 after the second magnetic layer 21 is formed. It is a figure. Second magnetic layer 21
After the formation, the magnetic field 23 generated from the first and second magnetic layers 16 and 21 is as shown in FIG. A magnetic coating material for forming the third magnetic layer 26 is applied to the first and second magnetic layers 1 and 2.
Direction of magnetic field 23 generated from 6, 21 and DC orientation magnetic field 2
Many magnetic powders of the third magnetic layer 26 gather in a portion where the direction of 0 is the same (a convex portion of the second magnetic layer 21), and a different portion (a concave portion of the second magnetic layer 21). ) Has
The magnetic powder does not collect, and after drying and solidification, it becomes as shown in FIG. 1 (6). In FIG. 1 (7), after the second magnetic layer 21 is formed, the signal recorded in the first magnetic layer 16 is erased and re-recorded from the second magnetic layer 21 (FIG. 1 (5)). FIG. 6 is a cross-sectional view of an intermediate product when a magnetic paint 24 is applied and a DC orientation magnetic field 20 is applied in order to form the third magnetic layer 26 of (6). In FIG. 1 (8), in order to form the third magnetic layer 26, the magnetic paint 24 is applied, and then the DC orientation magnetic field 20 is applied (FIG. 1 (7)), and the first and second magnetic layers 16, The direction of the magnetic field from the signal re-recorded in 21 and the direction of the DC orientation magnetic field 20 are the same, and the part a in which the magnetic fields strengthen each other and the part b in which the directions of the magnetic field from the signal and the DC orientation magnetic field 20 are different and the magnetic fields cancel each other out are weak. FIG. 3 is a cross-sectional view of an intermediate product after being dried and solidified by causing

FIG. 2 is a top view of a magnetic recording medium in which a protective layer and tracks are formed on the intermediate product of FIG. 1 (8), showing a case where a fixed signal that cannot be rewritten is used in combination with a method of making recording / reproduction of recorded information difficult. In the figure for explanation, there are shown a track 27 provided with a layer for recording dummy information and a track 28 provided with a non-rewritable fixed signal according to the present invention on a layer on which regular information is recorded.

3 is a cross-sectional view taken along line III-III of FIG. 2, showing a track 27 having a layer 29 having dummy information recorded thereon, on a layer 30 having normal information recorded therein.

FIG. 4 is a top view of a magnetic recording medium having a track 32 provided with a magnetic shielding layer 33 and a fixed signal irrewritable fixed signal track 28 on a layer 30 on which regular information is recorded.

5 is a cross-sectional view taken along line VV of FIG. 4, showing a track 32 in which a magnetic shielding layer 33 is provided on a layer 30 on which regular information is recorded.

FIG. 6 is a schematic view of a coating apparatus that coats, orients and dries the first magnetic layer.

FIG. 7 is a schematic diagram of a writing device that magnetically records a signal on a first magnetic layer.

FIG. 8 is a schematic view of a coating device that coats, orients and dries a second magnetic layer.

FIG. 9 is a schematic view of an apparatus for erasing / re-recording a signal magnetically recorded on the first magnetic layer.

FIG. 10 is a schematic view of a coating device that coats, orients and dries a third magnetic layer.

FIG. 11 is an output waveform of a fixed signal that cannot be rewritten,
In FIG. 11A, magnetic recording is performed on the first magnetic layer 16,
When the magnetic layer 21 and the third magnetic layer 26 are continuously formed, FIG. 11B shows that after the second magnetic layer 21 is formed,
The case where the third magnetic layer 26 is formed by erasing / re-recording is shown.

FIG. 12 is a schematic view of an apparatus for performing an evaluation test of the magnetic recording medium of the present invention.

[Explanation of symbols]

1 Unrolling Part 2 Rolled 188 μm PET Film 3 Coating Part 4 Orienting Part 5 Device for Erasing Signals Recorded in First Magnetic Layer 6 Drying Part 7 Direction of DC Orientation Magnetic Field 8 Roll (First Magnetic Layer Coating 9) Winding unit 10 Recording device: magnetic head 11 roll (magnetically recorded on the first magnetic layer) 12 roll (after formation of the second magnetic layer) 13 roll (signal erasing of the first magnetic layer, first) , Second
Re-recorded on the magnetic layer of) 14 roll (after formation of the third magnetic layer) 15 non-magnetic substrate 16 first magnetic layer 17 magnetic field of the recorded signal on the first magnetic layer 18 recorded on the first magnetic layer Magnetic field generated from generated signal 19 Magnetic paint for forming second magnetic layer 20 Direct-current orientation magnetic field 21 Second magnetic layer 22 Magnetic field of magnetic powder in second magnetic layer 23 Generated from first and second magnetic layers Magnetic field 24 Applied magnetic paint for forming third magnetic layer 26 Third magnetic layer 27 Track 28 Track 29 Layer of track 27 on which dummy information is recorded 30 Layer 31 on which normal information is recorded Nonmagnetic substrate 32 Track 33 Magnetic Concealment Layer 33-1 Soft Magnetic Material

Claims (5)

(57) [Claims] 1. A method of manufacturing a magnetic recording medium comprising laminating at least one kind of magnetic material powder on a non-magnetic substrate, wherein a magnetic paint using the magnetic material powder is applied onto the non-magnetic substrate. A step of forming a first magnetic layer by orientation and drying with a direct current magnetic field, and a step of magnetically recording a signal obtained by reversing the polarity of the residual magnetization on the first magnetic layer, A step of forming a second magnetic layer by applying a magnetic paint using a magnetic material powder on the recorded first magnetic layer, performing an orientation treatment with a DC magnetic field, and drying, A DC or AC magnetic field is used to erase the signal magnetically recorded in the first magnetic layer, and then the signal obtained by reversing the polarity of the residual magnetization from above the second magnetic layer is magnetically recorded. Magnetic material powder was used on A magnetic recording comprising a step of forming a third magnetic layer by applying a magnetic paint, performing an orientation treatment by a DC magnetic field, and drying and solidifying, and having a fixed signal that cannot be rewritten. Medium manufacturing method. 2. A magnetic recording medium manufactured by the method according to claim 1. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein the first magnetic layer is a magnetic layer made of at least one kind of magnetic powder material for recording a signal. Method for manufacturing magnetic recording medium. 4. A magnetic recording medium manufactured by the method according to claim 3. 5. The method of manufacturing a magnetic recording medium according to claim 1, wherein a protective layer containing a non-magnetic material such as aluminum powder or a white pigment is provided on the third magnetic layer, and a leuco dye type. The method includes a step of providing a heat-sensitive recording layer and a print recording layer such as a metal thin film layer of tin, aluminum, etc.
A method of manufacturing a magnetic recording medium, characterized in that the visibility is improved.