JP2011165233A - Magnetic recording medium and magnetic recording method to magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high coercivity magnetic recording medium that is compatible with a conventional read/write device and ensures safety against an external magnetic field, and a reading/writing method to the recording medium, in order to meet the requirements to a card manufacturer or a device manufacturer for increasing the coercive force of a magnetic card for bank having no change in magnetic characteristics. <P>SOLUTION: In the magnetic recording medium including a magnetic recording part formed on a card base body made of a non-magnetic material, a magnetic layer formed in the magnetic recording part is constituted of a magnetic body whose coercive force is reduced by pressurization and is restored when released from the pressurization. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium and a method for writing to and reading from a magnetic recording medium, and more particularly to a magnetic recording medium that is not easily affected by an external magnetic field and a method for writing to and reading from this magnetic recording medium.

  Magnetic recording media are, for example, cassette tapes and mini-discs for audio recording in the audio industry, video tapes for image recording, and credit cards in the distribution industry, bank cards in financial institutions, tickets in transportation in the business field. And prepaid cards are widely used.

The current standards for magnetic recording media (hereinafter also referred to as magnetic cards) are defined by ISO (International Organization for Standardization) and JIS (Japan Industrial Standard), and card manufacturers comply with this standard. Card.
In addition, in JIS, for magnetic cards used in financial institutions, the coercive force of magnetic materials used in magnetic cards is taken into consideration for the effects of external magnetic fields from an early stage. It was set to more than twice the magnetic force.
However, since magnetic products having a coercive force larger than that of the magnetic material used in the magnetic recording part of the magnetic card are used on a daily basis, there is a constant problem of erasing the magnetic information recorded on the magnetic card.
Therefore, the magnetic recording unit applied to credit cards and the like is also reviewed in the ISO standard (even in the JIS standard), and is used for the magnetic recording unit of the magnetic card in ISO / IEC 7811-6 (established in 1996). A magnetic material having a coercive force of 139 kA / m (1750 oersted) or 218 kA / m (2750 oersteds) was used.

  As described above, even if a new standard is established by ISO / IEC7811-6, conventional cards are still distributed in the market, and all magnetic cards using a magnetic material having a low coercive force are collected and cannot be newly replaced. Troubles caused by magnets used every day are not lost.

On the other hand, since the magnetic passbook used in the bank does not require compatibility between banks, a magnetic passbook in which the magnetic recording part has a laminated structure of a low coercive force part and a high coercive force part has been proposed ( For example, see Patent Document 1).
Also proposed is a method in which the magnetic recording portion has a two-layer structure of a low coercivity magnetic layer and a high coercivity magnetic layer, and data recorded in the low coercivity magnetic layer is used as a dummy.

JP 2006-65603 A

A request to set the coercive force of a magnetic card used in a bank to a higher value has been sent to card manufacturers and device manufacturers, but no change in magnetic properties has been implemented at present.
The present invention has been made to solve the above-described problems. A conventional read / write device can be used as it is, and it is safe against an external magnetic field. It is intended to provide a method.

  In order to achieve the above object, a first aspect of the magnetic recording medium of the present invention is a magnetic recording medium in which a magnetic recording portion is formed on a card base made of a nonmagnetic material. The magnetic layer is made of a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from pressurization.

  In addition, the second aspect is the first aspect in which the coercive force is reduced by pressurization and the card layer side of the magnetic layer composed of a magnetic material that returns to the original coercive force when released from the pressurization. Further, a magnetic layer made of a magnetic material whose coercive force does not change by pressurization is further formed.

  The third aspect is characterized in that, in the first or second aspect, the pressurization is performed by a magnetic head of a magnetic recording apparatus.

  Further, the fourth aspect is that in the third aspect, the range of pressurization by the magnetic head is 0.1 to 10 MPa, and when the coercive force is reduced by pressurization at that time and the pressure is released from the pressurization, The coercive force of the magnetic material returning to the coercive force of the magnetic material is reduced to 85 to 10% at the time of non-pressurization.

  According to a fifth aspect, there is provided a magnetic recording method for a magnetic recording medium according to any one of the first to fourth aspects, wherein the magnetic recording is performed with the magnetic recording medium being pressed against the magnetic head. It is a feature.

1) As in the first aspect, in a magnetic recording medium in which a magnetic recording portion is formed on a card base made of a nonmagnetic material, the magnetic layer formed on the magnetic recording portion has a reduced coercive force due to pressure, Card users are not affected by external magnetic fields such as clasps for handbags, magnets for office supplies, mobile phones, etc., because they are made of a magnetic material that returns to its original coercive force when released from pressure. Can be handled as On the card providing side, a conventional reading / writing device such as ATM can be used as it is.
Card manufacturers can also supply them as safe cards that satisfy various card standards.
2) In addition, as in the second embodiment, the magnetic layer card is made of a magnetic material that returns to the original coercive force when the coercive force is reduced by pressurization and released from the pressurization in the first embodiment. A magnetic layer made of a magnetic material whose coercive force does not change by pressurization is further formed on the substrate side, so that the coercive force is decreased by pressurization and returns to the original coercive force when released from pressurization. Can be handled as a magnetic shield layer.
3) Further, as in the third aspect, in the first or second aspect, the pressurization is performed by the magnetic head of the magnetic recording device, so that a conventionally used read / write device such as ATM is used. Can be used as is.
4) Further, as in the fourth aspect, in the third aspect, the range of pressurization by the magnetic head is 0.1 to 10 MPa, and at that time, the coercive force is lowered by the pressurization and released from the pressurization. When the card body is restored to its original coercive force, the coercive force of the magnetic material is reduced to 85 to 10% of the non-pressurized state. Can be handled as a card that is not affected by the external magnetic field, and a conventional read / write device such as ATM can be used as it is on the service providing side.
5) A magnetic recording method for a magnetic recording medium according to any one of the first to fourth aspects as in the fifth aspect, wherein the magnetic recording is performed with the magnetic recording medium being pressed against the magnetic head. As a result, the service providing side can use a conventional read / write device such as ATM as it is.

It is a figure for demonstrating an example of the magnetic recording medium of this embodiment, and the magnetic recording method to a magnetic recording medium. It is a figure for demonstrating an example of the AA line cross section of FIG. It is a figure for demonstrating another example of the cross section of the AA line of FIG. It is a figure for demonstrating the coercive force and output characteristic at the time of the magnetic recording of the magnetic-recording part by the magnetic body by which a coercive force falls by pressurization and it returns to the original coercive force when released from pressurization. It is a figure for demonstrating an example of the shield effect of the magnetic body which a coercive force falls by pressurization and returns to the original coercive force when it releases | releases from pressurization. The figure for demonstrating the electromagnetic conversion characteristic of a magnetic-recording part.

Hereinafter, an example of a magnetic recording medium and a magnetic recording method for the magnetic recording medium according to the present embodiment will be described with reference to the drawings.
As shown in FIG. 1, many magnetic cards (magnetic recording media) 1 have a magnetic recording portion 2 formed on a card base made of a non-magnetic material, and “ABC Bank” is formed on the same surface as the magnetic recording portion. Print information 3 such as a card name such as “cash card” and a logo is formed. Further, card information 4 is formed on the same surface as the magnetic recording portion by using embossed characters such as “123-0-456789”.
The magnetic recording unit 2 may be hidden by a card design or the like so that the presence of the magnetic recording unit cannot be visually recognized. Such a card is called a JIS II type card and is used for a bank cash card or the like.

Although not shown, unlike the above-mentioned JIS II type card, a magnetic recording part is formed on a card base made of a non-magnetic material, and printed information such as a card name and a logo is displayed on the opposite side of the surface on which the magnetic recording part is formed. A magnetic card that is formed and has card information formed by embossed characters or the like is used. Such a card is called a JIS I type card and is used for a credit card or a bank card other than Japan.
In many JIS I type cards, the magnetic recording part is wider than the JIS II type card, and the magnetic material is exposed.

With reference to FIG. 2, an example of the cross section along the AA line of FIG. 1 is demonstrated.
In the card base 100 of the magnetic card 1 of the present embodiment, the cover sheets 11 and 12 are laminated on both surfaces of the core sheet 12, and the magnetic layer 2 is formed on the exposed surface of the cover sheet 11. The exposed surface of the magnetic layer 2 has the same height.
Although not shown in the drawing, as described above, the exposed surface of the magnetic layer 2 may be hidden by a card design or the like so that the presence of the magnetic recording portion cannot be visually recognized.
The printing information 3 described with reference to FIG. 1 is normally printed on the surface of the core sheet 12, and the cover sheet 11 is bonded to protect the printing surface.
Similarly, printing on the back side is usually performed on the back side of the core sheet 12, and a cover sheet 13 is bonded to protect the printing side.

Here, an example of a magnetic recording method to the magnetic recording medium of the present embodiment will be described.
The magnetic layer 2 is made of a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from the pressurization. Although not shown, when the magnetic card 1 is inserted into the magnetic recording apparatus and the magnetic card 1 is conveyed by the card conveying roller in the magnetic recording apparatus, the magnetic recording head comes into contact with the exposed surface of the magnetic layer 2 and the contact pressure 1 Magnetic information is recorded while pressing at ~ 2 Mpa.
At the moment when the magnetic recording head comes into contact with the magnetic layer 2, the coercive force of the magnetic material is reduced to 25 to 22% by pressurization, and magnetic recording is performed in the state of the reduced coercive force.
The magnetic material formed on the magnetic card returns to the original coercive force at the moment when the magnetic card is released from the pressurized state of the magnetic head after the magnetic recording is completed, and is ejected from the magnetic recording apparatus.
The magnetic card is handled as a magnetic card having a high coercive force before being inserted into the magnetic recording apparatus and after being ejected from the magnetic recording apparatus.

With reference to FIG. 3, another example of a cross section taken along line AA of FIG. 1 will be described.
In the card base 100 of the magnetic card 1 of the present embodiment, the cover sheets 11 and 12 are laminated on both surfaces of the core sheet 12, and the magnetic layer 2 and the magnetic layer 21 are formed on the exposed surface of the cover sheet 11. The exposed surfaces of the cover sheet 11 and the magnetic layer 2 are the same height.
Although not shown in the drawing, as described above, the exposed surface of the magnetic layer 2 may be hidden by a card design or the like so that the presence of the magnetic recording portion cannot be visually recognized. Further, the magnetic layer 2 may be applied to the entire surface of the card and may serve as a shielding layer for the magnetic recording portion.
The printing information 3 described with reference to FIG. 1 is normally printed on the surface of the core sheet 12, and the cover sheet 11 is bonded to protect the printing surface.
Similarly, printing on the back side is usually performed on the back side of the core sheet 12, and a cover sheet 13 is bonded to protect the printing side.

The magnetic layer 2 is made of a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from the pressurization. The magnetic layer 21 is made of a magnetic material whose coercive force does not change when pressed.
When the magnetic card 1 is inserted into the magnetic recording apparatus and the magnetic card 1 is conveyed by the card conveying roller in the magnetic recording apparatus, the magnetic recording head comes into contact with the exposed surface of the magnetic layer 2 and a contact pressure of 0.1 to 10 MPa. Magnetic information is recorded while pressure is applied.
The magnetic layer 2 is formed on the back side (core sheet 12 side) of the magnetic layer 2 at the moment when the magnetic recording head comes into contact, the coercive force of the magnetic material is reduced to 85 to 10% by pressurization, and in the state of the reduced coercive force. Magnetic recording is performed on the magnetic layer 21 whose coercive force does not change by the applied pressure.
The magnetic layer 2 formed on the magnetic card returns to the original coercive force at the moment when the magnetic card is released from the pressurized state of the magnetic head after the magnetic recording is completed, and is ejected from the magnetic recording apparatus.

The magnetic layer 2 made of a magnetic material whose coercive force changes due to pressurization is formed with a lower coercive force than the magnetic layer 21 and serves as a magnetic shield layer for the magnetic layer 21.
The magnetic card is handled as a magnetic card having magnetic shielding properties before being inserted into the magnetic recording apparatus and after being ejected from the magnetic recording apparatus.

Referring to FIGS. 4 and 6, the coercive force and the output characteristics at the time of magnetic recording of the magnetic recording unit by the magnetic material that returns to the original coercive force when the coercive force is reduced by pressurization and released from the pressurization. explain. In FIG. 6, the vertical axis is (reproduction output voltage / reference peak output voltage) × 100, and the horizontal axis is (applied magnetic field / reference magnetic field) × 100.
Hereinafter, the coercive force “1” Oe is “0.0793” kA / m, but in the following description, the coercive force “1” Oe is described as “0.08” kA / m.
Comparative example 1 of Table 1 shown in FIG. 4 is a magnetic card in which a magnetic layer is formed of a magnetic material whose coercive force is 52 kA / m (650 Oe) and whose coercive force does not change by pressurization.
Comparative Example 2 is a magnetic card in which a magnetic layer is formed of a magnetic material whose coercive force is 220 kA / m (2750 Oe) and whose coercive force does not change by pressurization.
In the embodiment, the magnetic card has a magnetic layer formed of a magnetic material whose coercive force is 220 kA / m (2750 Oe) before pressurization and is reduced to 52 kA / m (650 Oe) when pressed with a force of 1 MPa. (When released from pressurization, the coercive force returns to 220 kA / m).
Here, the magnetic card used in Comparative Example 1 or Comparative Example 2 uses a magnetic material whose coercive force does not change due to pressurization, but strictly speaking, there are cases where the coercive force slightly decreases.
However, since the magnitude of the change is minute compared to the “magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from pressurization” in this embodiment, Here, it is described as “a magnetic material whose coercive force does not change”.

The magnetic layers of Comparative Examples 1 and 2 and the examples all had a residual magnetic flux (φr) of 1.5 × 10 nWb / cm (1.5 Mx / cm).
Further, the recording current value indicating 80% at the peak shown in FIG. 6 is not shown in the table, but it was 30 mA in Comparative Example 1, 150 mA in Comparative Example 2, and 30 mA in Example.
According to JIS, recording is performed within the frame of the rectangle 6 shown in FIG. 6, and the output signal voltage 5 is determined to be within the frame of the rectangle 6, and the recording indicating 80% of the peak time. From the current value, the optimum write current value of Comparative Example 1 and Example was set to 105 mA, and the optimum write current value of Comparative Example 2 was set to 525 mA. Each of the optimum write current values is a current value 3.5 times the recording current value indicating 80% of the peak.

As a result of writing all “1” signals to each magnetic card with the write current and measuring the output waveform by the magnetic read / write device, the output voltage is described in the “Recording” column of “Magnetic output” in Table 1. It was street.
Next, the surface of each recording portion was traced twice with a permanent magnet having a coercive force of 80 kA / m (1000 Oe), and the output waveform was again measured by a magnetic reading / writing device.
The measurement results are as shown in Table 1, and no output was obtained from the magnetic card of Comparative Example 1.
Further, from the magnetic card recorded with the optimum write current value of Comparative Example 2 (the optimum write current value 525 mA of the magnetic card having a coercive force of 220 kA / m), the low coercivity write current value of the example (coercive force 52 kA / m). A normal output (5 V) was obtained from the magnetic card recorded at the optimum write current value of 105 mA), and no decrease in output was observed in any of the magnetic cards.
In other words, although Comparative Example 1 can record well at 105 mA, it is demagnetized by the magnet, information cannot be read, and Comparative Example 2 does not cause demagnetization by the magnet, but a high current value of 525 mA is necessary for good recording. It was necessary. Only the examples were able to record with a low recording current and no demagnetization by the magnet.

Referring to FIGS. 5 and 6, a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from pressurization (hereinafter, the magnetic layer made of this magnetic material is also referred to as a shield layer). An example of the shielding effect will be described.
Comparative Examples 1 and 2 are examples of magnetic cards without the shield layer described in FIG. The embodiment is an example of a magnetic card provided with the shield layer described in FIG.

With the magnetic read / write device described in FIG. 4 on the magnetic cards of Comparative Examples 1 and 2 and Example, an all “1” signal was written to each magnetic card with the write current, and the output waveform was measured.
The result was as described in the “Recording” column of “Magnetic output” in Table 2.
Next, the surface of each recording portion was traced twice with a permanent magnet having a coercive force of 80 kA / m (1000 Oe), and the output waveform was again measured by a magnetic reading / writing device.
As a result of the measurement, the output voltage was as shown in Table 2, and no output waveform was obtained from the magnetic card of Comparative Example 1.
Further, from the magnetic card recorded with the optimum write current value of Comparative Example 2 (the optimum write current value 525 mA of the magnetic card having a coercive force of 220 kA / m), the low coercivity write current value of the example (coercive force 52 kA / m). A normal output (5 V) was obtained from the magnetic card recorded at the optimum write current value of 105 mA), and no decrease in output was observed in any of the magnetic cards.
In other words, although Comparative Example 1 can record well at 105 mA, it is demagnetized by the magnet, information cannot be read, and Comparative Example 2 does not cause demagnetization by the magnet, but a high current value of 525 mA is necessary for good recording. It was necessary. Only the examples were able to record with a low recording current and no demagnetization by the magnet.

A magnetic head pressure measurement device and measurement conditions will be described.
For measurement of the magnetic head pressure, a prescale LLW (for extremely low pressure) manufactured by Fuji Photo Film Co., Ltd. is pasted on the surface of the magnetic card (the thickness of the card base is 0.76 mm) on which the magnetic recording portion is formed. It was measured. The prescale color-development portion was measured with a prescale concentration meter FPD-305 manufactured by Fuji Photo Film Co., Ltd., and a prescale dedicated pressure converter FPD-306 manufactured by Fuji Photo Film Co., Ltd., and the pressure value was determined. The magnetic head pressure of the magnetic read / write device used in this embodiment was 1 MPa.

(material)
Hereinafter, materials used for the magnetic recording medium of the present embodiment will be described.
1) Examples of materials used for the card substrate.
For example, a polyvinyl chloride resin, an amorphous polyethylene terephthalate resin (PETG), a polylactic acid resin, a triacetate resin, a polypropylene resin, a plastic such as a polycarbonate resin, a non-ferrous metal such as aluminum, paper, or the like is used as appropriate.
2) An example of a material used for a magnetic body whose coercive force is reduced by pressurization and returns to the original coercive force when released from pressurization.
For example, a known magnetic powder such as γ-Fe ₂ O ₃ , Co-coated Fe ₂ O ₃ , Fe ₃ O ₄ , Co—Cr, Co—Ni, Ba ferrite, Sr ferrite, etc. in a binder dissolved in a solvent. Disperse to form a magnetic material.
3) Examples of materials used for the binder.
A butyral resin, a vinyl chloride / vinyl acetate copolymer resin, a urethane resin, a polyester resin, a cellulose resin, an acrylic resin, a styrene / maleic acid copolymer resin, and the like are appropriately selected for use. Further, a rubber-based resin such as nitrile rubber or a urethane elastomer can be added as necessary. Further, as a magnetic material dispersing material, a pigment such as a surfactant, a silane coupling agent, a plasticizer, and carbon is added as necessary.

(Formation of magnetic layer)
It is applied to a heat and solvent resistant film such as a polyethylene terephthalate film or a polyimide film by a known coating apparatus such as a gravure coater, a roll coater or a knife edge coater.
When the magnetic material is oriented in the coating device, for example, the permanent material is passed through a solenoid coil between the permanent magnets and oriented, and then passed through a drying device to dry the paint.
Moreover, it can also form by a vacuum evaporation method, sputtering method, plating method, etc. using the magnetic material of a high coercive force.
The magnetic layer applied on the carrier film by the above-described method is slit to a predetermined width together with the carrier film, and transferred to the card substrate (cover sheet) by a method such as thermal transfer.

  It can be used for, for example, a magnetic card used in a financial institution, a credit card used in the distribution industry, etc. that are hardly affected by an external magnetic field.

DESCRIPTION OF SYMBOLS 1,10 Magnetic recording medium 2 Magnetic recording part, magnetic layer 3 Print information 4 Card information 5 Output signal voltage 5
6 Rectangular 11, 13 Cover sheet 12 Core sheet 21 Magnetic layer made of a magnetic material whose coercive force does not change by pressurization 100 Card base

Claims (5)

In a magnetic recording medium in which a magnetic recording part is formed on a card base made of a nonmagnetic material,
2. A magnetic recording medium according to claim 1, wherein the magnetic layer formed on the magnetic recording portion is made of a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from the pressurization. The magnetic recording medium according to claim 1,
Magnetic layer made of a magnetic material whose coercive force does not change due to pressurization on the card substrate side of the magnetic layer composed of a magnetic material whose coercive force is reduced by pressurization and returns to the original coercive force when released from pressurization A magnetic recording medium characterized in that is further formed.     3. The magnetic recording medium according to claim 1, wherein the pressing is performed by a magnetic head of a magnetic recording device.     4. The magnetic recording medium according to claim 3, wherein the range of pressurization by the magnetic head is 0.1 to 10 MPa, and the coercive force is lowered by pressurization at that time and the original coercive force is released from the pressurization. A magnetic recording medium characterized in that the coercive force of a magnetic material that returns to <RTIgt; A method of magnetic recording on a magnetic recording medium according to claim 1,
A magnetic recording method for a magnetic recording medium, wherein the magnetic recording is performed in a state where the magnetic recording medium is pressed against a magnetic head.

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