JPH0973629A - Magnetic recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium provided with a high degree of security function by having a non-writable fixed magnetic pattern region and non-fixed recording region on one sheet of magnetic card. SOLUTION: A supporting base body 2 is coated with a magnetic coating material 4 at a thickness of about 100μm by a coating head device 3 in a phase 1. The magnetic particles 4A suspend and exist uniformly in a random state in a vehicle 4B in this state. A magnetization effect is applied in the vertical direction of the base body by a magnetizing device 5 and the state in which the coarse/dense states of the magnetic particles are generated in the coating film is attained by the effect of the attraction/release in a phase 2. The axes of easy magnetization of the magnetic particles directed toward the vertical direction are oriented toward the coating applying and traveling direction by a magnetic orientation device 6 in a phase 3. The solvent in the magnetic coating material is evaporated by a drying furnace 7 and the thickness is reduced to about 15μm, by which the coarse/dense states of the magnetic particles are fixed into the coating film in a phase 4.

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 having a high security function such as a cash voucher card (prepaid card) and an ID card, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Magnetic cards have recently been used as cash vouchers. However, the ease of recording / reproducing, which is a feature of magnetic cards, also means the ease of copying, and it is necessary to take various measures to prevent forgery. Just like a cash card, you need to keep your eyes on the ease of card duplication.
There is a method to avoid abuse by using a security system that limits users, such as a personal identification number, but for magnetic cards that are used without specifying the user, various ways to add security functions to the card are devised. Has been done. For example, 1) a method of hiding a magnetic signal so that it cannot be easily read from the outside, 2) a method that involves a change in structure before and after use, and 3) a method of adding an authentication mark unique to a card and detecting the same. This is a typical example. Of these, the method of applying and detecting the individual authentication mark of 3) is mainly classified into an optical or magnetic method. The latter method of forming and detecting a magnetic authentication mark is described in, for example, Japanese Patent Laid-Open No.
-208725 and Japanese Unexamined Patent Publication No. 1-208726, a method of imparting a unique magnetic barcode to a magnetic card by screen printing or the like, and Japanese Patent Publication No. 3-68543, the orientation of the magnetic recording layer is partially A method of changing and fixing, or a magnetic signal is recorded on a preformed first magnetic layer and a second magnetic layer is coated on the first magnetic layer to form a magnetic reversal interface of the first layer, as in Japanese Patent Laid-Open No. 6-203366. A method of causing concentration of the second layer magnetic particles and drying and fixing is proposed.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The problem to be solved by the present inventor is that a unique authentication signal inherent in each card is inherent, and the unique signal has a high density and a high output and cannot be rewritten. It is an object of the present invention to provide a magnetic card which has a fixed magnetic signal and which has a variable magnetic recording / reproducing area which is normally used and which cannot be easily counterfeited, and a production method capable of easily mass-producing the magnetic card. When such a magnetic recording medium is completed, it is possible to construct a magnetic card security system that is extremely difficult to forge in combination with the output reproduction method of the unique signal.

In view of the prior art from this point of view, in applying a magnetic bar code by screen printing as typified by the above, since the bar code pattern depends on the printing plate, a specific pattern is printed in a certain amount. However, it is not possible to add a unique pattern to each card. With the above method, at least from the disclosed contents, it is considered that the output is small and the recording density is also low, and it is understood that it is difficult as a method of giving a unique signal to many cards. It In the above invention, the recording density of the unique signal is higher than that of the conventional method, and different non-rewritable unique signals can be given to each card, but the presence of the first magnetic layer is indispensable.
For this reason, there is a drawback that the structure of the medium is limited and the manufacturing method is complicated. Moreover, since it is an action due to the minute magnetization amount of the first magnetic layer, the output value of the unique signal formed in the second magnetic layer is There is still no sufficient solution, such as expected to be small in general.

[0005]

According to the present invention, in a step of applying a magnetic paint on a substrate, when the magnetic paint is not dried, the magnetic paint is applied to any position in the application width direction from the top of the application surface to the tip. A rectangular parallelepiped type electromagnet having an appropriate shape is brought close to the coil, and a predetermined signal current is passed through the coil to cause the generation / disappearance of the magnetic pole at the tip of the electromagnet. By the effect, the magnetic particles in the magnetic paint are partially unevenly distributed, and a sparse and dense pattern of the magnetic particles is formed in the coating film. Then, the easy axis of magnetization of the magnetic particles in the paint that is vertically oriented by the suction action. By orienting the magnetic particles in the magnetic paint in the direction of application under an orienting magnet and then drying and fixing the coating film in a drying oven to form a dense and dense pattern of the magnetic particles.
Provided is a method of manufacturing a magnetic recording medium having a non-rewritable fixed magnetic signal pattern area and a non-fixed magnetic recording area in the same magnetic layer. The present invention also provides a magnetic recording medium manufacturing apparatus comprising means for carrying out the steps of the above method. The present invention also provides a magnetic recording medium manufactured by the above method, which has a non-rewritable fixed magnetic signal pattern area and a non-fixed magnetic recording area in the same magnetic layer. According to the method of the present invention, in the fixed magnetic signal pattern area, the easy axis of magnetization of the magnetic particles is oriented in a direction advantageous for output reproduction, so that a sufficiently large discrimination output can be obtained as compared with the conventional case. When this magnetic recording medium was cut out into a card shape and the output of the sparse and dense pattern portion was measured by a predetermined reproducing head, a desired clear and high output signal could be obtained. The dense and dense pattern of magnetic particles similar to a magnetic bar code is a fixed signal that is not rewritable and has a high density, and if the signal current applied to the electromagnet is devised, each card is It can be formed as a different unique authentication signal.

[0006]

The magnetic recording medium according to the present invention has a high density non-rewritable fixed magnetic signal peculiar to the card. Therefore, if the same is to be duplicated, the same manufacturing process and apparatus are indispensable. Counterfeiting is impossible without factory equipment. In addition, if you devise a method of concealing the unique signal, you can not distinguish the sparse or dense state from the outside, so it is not easy to see, and if you scrutinize a used or purchased card, you can know the unique signal of the card. Even if it can be duplicated, there is no meaning in the limited use of only one sheet, and it will be economically unreasonable. According to the present invention, for example, a JIS II type card is manufactured, and the fixed signal recording area length is set to 5 cm, and 1 bit per 1 bit is assumed.
If a fixed signal of mm length is formed, 50 bi
t, it is possible to form as many as 2 ⁵⁰ different eigensignals in a simple calculation. Further, if a plurality of fixed signal recording track areas are provided and used in combination, it is possible to deal with an almost infinite unique signal.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments will be described in detail with reference to the accompanying drawings. FIG. 1 is an outline of installation of each part of a magnetic paint coating apparatus according to the present invention. 1 is an unwinding part of a supporting substrate, 2 is a supporting substrate, 3 is a magnetic paint coating head device, 4 is magnetic paint, 5 is a magnetic paint magnetizing device, 6 is a magnetic orientation device, 7 is a drying oven, 8 is a coated roll It is a winding section. The support base film 2 starts the unwinding part 1 in order from the left to the right, and the magnetic paint 4 is applied by the magnetic paint coating head device 3, and the magnetic paint magnetizing device 5, the orienting device 6, and the drying oven 7 are provided. It is wound up by the winding unit 8 in order.

FIG. 2 is a schematic diagram showing the state change of the magnetic particles in the magnetic coating material during the process of forming the coating film of the magnetic recording medium according to the present invention. In the phase 1, the magnetic paint 4 is applied to the supporting substrate 2 by the coating head unit device 3, for example, 1
It is in a state of being applied with a thickness of about 00 μm. In this state, the magnetic particles 4A (the axis of easy magnetization is shown by a long line) are uniformly present in the vehicle 4B in a random state. Phase 2 represents a state in which the magnetizing device 5 applies a magnetizing action in the vertical direction of the substrate, and the attraction / release action of the magnetizing action causes the magnetic particles to become sparse / dense in the coating film. Phase 3 represents a state in which the easy axis of magnetization of the magnetic particles oriented in the vertical direction is oriented in the coating traveling direction by the magnetic orientation device 6. Phase 4 is drying oven 7
Shows that the solvent in the magnetic paint is evaporated, the thickness is reduced to about 15 μm at the same time, and the density of the magnetic particles is fixed in the coating film.

As the supporting base 2, a white polyester film having a thickness of 188 to 250 μm is used in many magnetic cards, but the film used in the present invention has flexibility and can be continuously wound by an apparatus. Anything that can be done is acceptable. Further, it is of course possible to use a film in which a lower layer including a magnetic layer of a single layer or more has already been formed, but in this case, the solvent of the magnetic paint to be coated permeates the lower layer, the viscosity of the paint increases, and the mobility of the magnetic particles increases. Be careful not to damage it. The magnetic paint coating head device 3 has various coating methods such as gravure coating, reverse roll coating, knife coating, wire bar coating, nozzle coating, and hopper coating, but it is a method capable of obtaining a smooth coating surface for magnetic recording. Anything is fine.

The magnetic paint 4 is composed of γ-Fe ₂ O ₃ and Fe ₃ O.
₄ , any magnetic coating material containing magnetic particles such as Co-ferrite, Ba-ferrite, Ba-ferrite, iron and sendust can be used as long as it is a magnetic coating material that can be used for the production of a usual coating type magnetic recording medium. In addition to maintaining fluidity, it is desirable that the viscosity of the paint and the volume concentration of the magnetic particles are generally low so that the magnetic particles can move freely in the paint. As the magnetic orientation device 6, a facing magnet or a Helmholtz coil is usually used, but any of them may be used. However, considering the influence of the reversal of the orientation magnetic field on the magnetic particles, the latter is considered to be more advantageous for the characteristics.

FIG. 3 is a schematic diagram of the simplest construction of the coating film magnetizing apparatus 5 according to the present invention. The magnetizing device comprises a rod-shaped core 5A made of a soft magnetic material and a coil 5B. 5C represents a magnetic field generated when a current is applied. The material of the core 5A may be any material such as pure iron, permalloy, sendust, etc. which are used for general cores. The magnetizing device is basically a system that increases the magnetizing force in the vertical direction of the coating film, for example, as shown in FIG. 4, the yokes 5A and 5D having the same shape with the coating film substrate sandwiched therebetween.
In the case where the coating substrate is sandwiched by a gap, it is also possible to use a ring-type electromagnet when the substrate substrate is narrow. The shape of the part close to the coating surface of the core is almost rectangular, the width is equal to the track width of the fixed magnetic recording layer to be formed, and the length is appropriately designed to obtain the desired recording density of the fixed magnetic recording pattern. To be done. When a signal current flows through the coil, a magnetic pole is generated at the tip of the electromagnet core, and the magnetic particles in the coating film are held back by suction, so that the coating film that runs away from the bottom has a small amount of magnetic particles [sparse]. On the contrary, when the coil current is cut off, the attraction is released, the magnetic particles held by the magnetic poles up to that point are released, and [denseness] of particle existence occurs in the coating film. In this way, a [sparse] / [dense] pattern corresponding to the pulse signal flowing through the coil is formed.

FIG. 5 is a schematic diagram of reading the fixed signal thus created. The method of reading a fixed magnetic signal can be used as it is because the form of the signal is similar to a magnetic bar code. That is, FIG.
As described above, the normal ring reproducing head 10 is brought into contact with the fixed signal track portion to drive the card. At this time, if the coercive force of the magnetic particles forming the fixed signal is small and the magnetic pole is not present or is small between the sparse and dense regions even if a DC magnetic field is applied,
The reproducing coil 10B reads the fixed magnetic signal while applying a DC bias current capable of saturation magnetization to the bias coil 10A of the ring head. When the magnetic particles have a high coercive force as shown in FIG. 6, in addition to the above method, the permanent magnet 11 is made to approach in advance to generate a magnetic pole at the sparse and dense edges of the fixed signal, and then the reproducing head 10 'and Reproduction coil 1
It is also possible to read at 0B '.

FIG. 7 shows an example of the correlation between the signal current flowing in the coil and the density and reproduction output of the coating film formed.
As an easy-to-understand example, an RZ (return zero) type DC pulse current is given as the current flowing through the coil. At this time, 1 pulse corresponds to 0 and 2 pulses correspond to 1 per unit time. [Sparse] of the magnetic particles is generated at the time of the attraction action accompanying the generation of the magnetic pole, and [dense] is generated according to the disappearance of the magnetic pole. The reproduction output occurs at the edge of the [dense] pattern of the coating film. Although the case where the magnetization signal current waveform of the coil is the RZ type DC signal has been described above, the same result can be obtained even if the waveform is the FM type signal waveform.

FIG. 8 is a plan view of an example in which the magnetic recording medium thus manufactured is cut out into a card shape. The card 20 has a fixed magnetic recording track area 20A and a variable magnetic recording / reproducing area 20B on the same surface of the magnetic recording layer. It should be noted that it is easy to form a plurality of fixed magnetic recording tracks in the same plane if necessary.

[0015]

According to the present invention, the magnetic recording medium having the variable magnetic recording region and the singular or more non-rewritable fixed magnetic recording regions in the same magnetic recording layer can be magnetically produced by the above-mentioned manufacturing method. Regardless of the shape property of the magnetic material in the paint, or whether it is a single layer or a laminated system, a fixed signal pattern and the signal track area position can be independently set to manufacture. Therefore, the magnetic card manufactured by the method of the present invention can be widely applied from simple and inexpensive cards to complicated and expensive cards with various combinations, and can be used for prepaid cards, other cash vouchers, magnetic commuter passes, and personal cards. It can be expected to be used in various magnetic card systems that require advanced security functions such as authentication cards.
It can also be noted that the manufacturing apparatus can be generally used as it is, and therefore the investment amount for mass production of the product of the present invention is considered to be extremely small.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a magnetic paint coating apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a state change of magnetic particles in a magnetic coating material during a process of forming a coating film on a magnetic recording medium according to the present invention.

FIG. 3 is a schematic diagram of a coating film magnetizing apparatus according to the present invention.

FIG. 4 is a schematic view of another coating film magnetizing apparatus according to the present invention.

FIG. 5 is a schematic diagram of fixed signal reading.

FIG. 6 is a schematic diagram of another reading of a fixed signal.

FIG. 7 is a diagram showing an example of a correlation between a signal current passed through a coil and the density and reproduction output of a coating film formed.

FIG. 8 is a plan view of an example in which a magnetic recording medium manufactured by the method of the present invention is cut into a card shape.

[Explanation of symbols]

 1: Unwinding part of support base 2: Support base 3: Magnetic paint coating head device 4: Magnetic paint 5: Magnetic paint magnetizing device 5A: Core 5B: Coil 5C: Magnetic field 5D: Yoke 6: Magnetic orientation device 7: Drying Furnace 8: Coated roll winding section 10: Reproduction head 10A: Bias coil 10 ': Reproduction head 10B': Reproduction coil

Claims (3)

[Claims] 1. A magnetic signal is applied in the vertical direction of the coating film by bringing one or a plurality of electromagnets close to an arbitrary position in the width direction of the coating film in a state where the coated magnetic paint on the support is undried. The magnetic particles in the coating film are sparsely and densely distributed by the effect of suction and release, and then subjected to a normal orientation treatment to direct the easy axis of magnetization of the magnetic particles to the coating direction. A method of manufacturing a magnetic recording medium, which is produced by drying and fixing, and which has a non-rewritable fixed magnetic signal pattern area and a non-fixed magnetic recording area in the same magnetic layer. 2. A coating portion of a magnetic coating material on a support, and a magnetic coating material coated on the support is magnetized in the vertical direction of the coating film at an arbitrary position in the width direction of the coating film surface in an undried state. A coating film magnetizing device which is composed of a single or a plurality of electromagnets for giving a signal and which causes the magnetic particles in the coating film to be dense and dense by the effect of its magnetic attraction and release, and an easy axis of magnetization of the magnetic particles. A magnetic paint coating device, which comprises an orienting device for directing a coating direction and a drying oven, which are successively installed. 3. In the same magnetic layer, a single or a plurality of non-rewritable unique magnetic signal pattern track regions due to the density of magnetic particles and a non-fixed signal recording / reproducing region in which magnetic particles are uniformly dispersed are combined. The magnetic recording medium obtained by the method of claim 1, wherein the easy axis of magnetization of the magnetic particles that are present and that constitute all the recording layers are oriented in the coating direction.