JPH07272132A - Magnetic marker - Google Patents

Abstract

PURPOSE:To identify many articles by laminating a dry coating film where magnetically hard magnetic powder is distributed in a binding agent, a metallic plate without magnetic distortion or wire and dividing the paint film at an equal interval in the longitudinal direction. CONSTITUTION:The metallic plate 2 whose size of magnetic distortion is 0-1PPM, an adhesive layer 3 and peeling paper 4 are laminated on a non- magnetic supporting body A provided with the magnetic layer 1 consisting of the dry coating film where magnetic powder consisting of a hard magnetic material is distributed in the binding agent. For generating a bias magnetic field, the non-magnetic supporting bodies A provided with the magnetic layers 1 are arranged on the metallic plate 2 without magnetic distortion in plural strips at the equal intervals, and the magnetic layers 1 are magnetized by a permanent magnet and the like. The metallic plate 2 without magnetic distortion shows a hysteresis loop having a permanent magnetic permeability part and a part having magnetic permeability different from the part in a state where the bias magnetic field from the magnetic layer 1 is received, and the boundary appears as an inflection point. The individual articles can be identified by using the inflection point for a marker.

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,
More specifically, the present invention relates to a non-contact magnetic recording medium for reading identification information such as collation data, and can also be used for preventing forgery in a magnetic card.

[0002]

2. Description of the Related Art Magnetic cards are bank cash cards,
It is widely used for passbooks, commuter passes for trains, and tickets, but it is mechanically worn and damaged because it is read by contact. As a non-contact type and simple information medium, a bar code system is generally used, but there are problems such as a use environment and difficulty in writing.

Therefore, as a new attempt for identification or identification in a non-contact manner, in Japanese Patent Laid-Open No. 1663087/1992, a marker formed by combining at least two kinds of amorphous metal thin wires having different magnetic field values of large Barkhausen discontinuity is used by an appropriate means. It has been proposed to recognize a time-series pulse which is attached to an article to be identified and in which the generation position of a pulse signal in response to an incident magnetic field differs depending on the combination of the metal thin wires.

However, in the marker for recognizing the above-mentioned time-series pulse, in order to prepare the amorphous metal thin wires having the large Barkhausen discontinuity generating magnetic field values, the heat treatment condition which is a manufacturing condition for each metal thin wire, that is, The temperature, tension, etc. had to be changed. Moreover, it was not possible to write repeatedly like a magnetic card.

As a marker for solving such a drawback that repeated writing is not possible, a dry coating film formed by dispersing magnetic powder in a binder and a metal plate or a laminate in which wires are laminated, There is known a magnetic marker which can respond depending on the presence / absence of a bias magnetic field from the coating film to output a signal to the incident magnetic field or not to output a signal.

[0006]

However, although the above-mentioned marker can be repeatedly written, the entire coating film has only one N pole and one S pole when viewed in the longitudinal direction. It is magnetized and used. Therefore, although the presence or absence of the marker can be confirmed in response to the incident magnetic field, it is possible to determine whether or not the article attached with the marker is one of many articles in response to the incident magnetic field. It could not be recognized from the incoming output signal.

[0007] Therefore, it is expected that a magnetic marker which can discriminate not only the presence / absence of an article but also what kind of article the marker is attached to is one of many articles. The problem to be solved by the present invention is that it is possible to perform repetitive writing, and in response to the writing signal, whether or not there is a presence in response to an incident magnetic field, and there are many articles to which a marker is attached. An object of the present invention is to provide a magnetic marker capable of recognizing what kind of article it is.

[0008]

In order to solve the above-mentioned problems, the present inventor has conducted extensive studies and, as a result, magnetized a dry coating film of a conventional magnetic marker formed by dispersing magnetic powder in a binder. Then, upon providing a bias magnetic field, it was found that the above problem can be solved by magnetizing the coating film so as to be equally divided in the longitudinal direction at equal intervals, and completed the present invention.

That is, in order to solve the above-mentioned problems, the present invention provides a dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder, and a metal plate or wire (magnetism-free plate). In the state where the coating film (A) is not magnetized, the metal plate or the wire (B) generates a continuous magnetic field value in response to an incident magnetic field whose magnetic field strength fluctuates. Output signal based on the discontinuous magnetic field value is not generated, but when the coating film (A) is magnetized at equal intervals in the longitudinal direction, the metal plate or wire (B) is
Has a magnetic permeability part different from the constant magnetic permeability part and the constant magnetic permeability part, and based on the difference in the magnetic permeability, generates an output signal based on a discontinuous magnetic field value, and The present invention provides a magnetic marker characterized by being made to respond to it.

In order to solve the above-mentioned problems, the present invention provides a dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder, and a metal plate or a wire (magnetism-free plate). In the state where the coating film (A) is not magnetized with respect to the incident magnetic field whose magnetic field strength fluctuates, the metal plate or the wire (B) has a magnetic field H-magnetic flux density B. A state in which a continuous magnetic field value is generated in the hysteresis loop on the coordinates and an output signal based on the discontinuous magnetic field value is not generated, but the coating film (A) is magnetized in equal parts in the longitudinal direction at equal intervals. Then, the metal plate or wire (B) has a constant magnetic permeability, and the metal plate or wire (B) has at least two inflection points in the hysteresis loop on the magnetic field H-magnetic flux density B coordinates. Output signal based on discontinuous magnetic field No, to provide a magnetic marker, characterized in that the manner in response to the incident magnetic field.

Further, in order to solve the above-mentioned problems, the present invention provides a dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder on one surface of a non-magnetic support, The adhesive layer is provided on the other surface, and the adhesive layer is composed of a metal plate having no magnetostriction or a laminate in which the wire (B) is fixed, and the coating film (A) is applied to the incident magnetic field whose magnetic field strength fluctuates. In the non-magnetized state, the metal plate or the wire (B) generates a continuous magnetic field value in the hysteresis loop on the magnetic field H-magnetic flux density B coordinates and does not generate an output signal based on the discontinuous magnetic field value. In the state where the coating film (A) is magnetized at equal intervals in the longitudinal direction, the metal plate or wire (B) exhibits constant magnetic permeability, and the metal plate or wire (B) is Magnetic field H-Magnetic flux density B Both the output signal based on the discontinuity of the magnetic field values generated by having two or more inflection points, to provide a magnetic marker, characterized in that the manner in response to the incident magnetic field.

First, terms and the like frequently used in the present invention will be specifically described.

In the present invention, "constant magnetic permeability" means that the magnetic flux density B is linear with respect to the magnetic field H in the hysteresis loop, and the magnetic permeability is constant without being strongly dependent on the magnitude of the incident magnetic field ( = Constant magnetic permeability).

All magnetizable substances have their own magnetic properties, and when a given magnetic field is applied, the magnetic flux density changes correspondingly. Take the magnetic field H on the horizontal axis,
Further, the magnetic flux density B is taken on the vertical axis, a coordinate system of the magnetic field H-the magnetic flux density B is provided, and a change in the magnetic flux density with respect to the change in the magnetic field is plotted as a "hysteresis loop" (hereinafter, the magnetic field H- The coordinates of the magnetic flux density B are called H-B coordinates.). When magnetized, this loop goes around once every cycle. This hysteresis phenomenon is "hysteresis". Therefore, this hysteresis loop shows an inherent property of the metal plate or the wire.

"A state in which magnets are magnetized at equal intervals and in equal parts"
Means that the entire length is divided into two or more parts and is magnetized, and the divided magnetized areas are all equally spaced. In the present invention, "multi-division"
Is a natural number of 2 or more.

The term "magnetically hard magnetic powder" means a magnetic powder made of a hard magnetic material, and is usually 300-5.
Those having a coercive force of 000 Oersted are mentioned.

"No magnetostriction" means that there is substantially no magnetostriction, and to exemplify the range, for example, 0 to
1 PPM (including zero).

In short, the marker of the present invention has a technical constitution of "magnetizing a hard magnetic coating film at equal intervals in the longitudinal direction into multiple portions" and a technical constitution of "using a metal plate or wire without magnetostriction". It is characterized in that it is combined with the configuration. Coated film (A) magnetized in the longitudinal direction at equal intervals and equally
Is a source of a bias magnetic field, which generates a bias magnetic field for giving uniaxial anisotropy to a metal plate or wire (B) having no magnetostriction, which will be described later.

The mechanism by which the marker obtained by the above technical structure of the present invention responds to an incident magnetic field whose magnetic field strength fluctuates by generating and generating discontinuous generated magnetic field values caused by hysteresis will be described.

The magnetic marker of the present invention exhibits a hysteresis loop as shown in FIG. 5, for example. Hereinafter, the principle will be specifically described with reference to FIGS. The strength of the bias magnetic field is preferably smaller than that of the incident magnetic field described later.

Generally, the main energy of a magnetized magnetic material consists of magnetization energy, anisotropic energy, elastic energy due to magnetostriction, and domain wall energy. Figure 1
A metal plate 2 having a high magnetic permeability of which the magnitude of magnetostriction is 0 to 1 PPM, which is subjected to a bias magnetic field from a magnetic layer 1 composed of a magnetic coating film uniformly magnetized at equal intervals as shown in FIG. Considering this, if the bias magnetic field is sufficiently larger than the coercive force of the metal plate 2, the elastic energy and the domain wall energy are 0, and the magnetic energy of the metal plate 2 is the magnetization energy and the anisotropic energy.

When an external magnetic field Hex is applied to the structure shown in FIG. 1 from the direction of the arrow and the magnitude of the external magnetic field Hex is sufficiently smaller than the magnitude of the bias magnetic field, as shown in FIG. It is considered that the energy and the anisotropy energy are in a balanced state, the energy change is small with respect to the change of the external magnetic field Hex, and the magnetic moment m of the metal plate 2, that is, the magnetic flux density and the like are not changed.

Next, when the magnitude of the external magnetic field Hex is larger than the magnitude of the bias magnetic field, it is considered that the magnetic moments m of the portion of the metal plate 2 receiving the bias magnetic field are aligned and rotate in the direction of the external magnetic field. .

As a result, as shown in FIG. 3, the metal plate 2 to which the bias magnetic field is applied from the magnetic layer 1 apparently has the uniaxial anisotropy in the bias magnetic field direction and the external magnetic field H.
When ex is not added, the magnetic moment m is oriented in the easy magnetization direction, and the anisotropic magnetic field HA is in that direction.
Further, in the present invention, the bias magnetic field is applied to the metal plate 2 so that the metal plate 2 is evenly divided into equal parts. Therefore, when the metal plate 2 as a whole is viewed as shown in FIG. The vector sum is apparently oriented in the direction of 90 ° with respect to the external magnetic field. In this case, regardless of the direction of the magnetic moment m of the metal plate 2, the magnetic susceptibility is constant and a hysteresis curve which is a constant magnetic permeability with respect to the change of the external magnetic field is obtained.

In the present invention, the waveform shape of the hysteresis loop of the metal plate or the wire (B) having no magnetostriction when the magnetic field H is not received (that is, when the bias magnetic field is not received) is not important. However, in that state, it usually has a normal square hysteresis loop in many cases.

In the marker of the present invention, the metal plate or wire (B) having no magnetostriction is apparently the hysteresis of the model shown in FIG. 5 under the condition that the bias magnetic field from the coating film (A) is received. Indicates a loop. That is, when a metal plate or wire (B) having no magnetostriction is subjected to a bias magnetic field, as shown in FIG. 5, its hysteresis loop has a portion having a constant magnetic permeability and a portion having a magnetic permeability different from the constant magnetic permeability portion. , And their boundaries appear as inflection points. In the present invention, this inflection point is used for the marker response.

In the present invention, the magnetic field value generated by this inflection point is called the discontinuous generated magnetic field value. Therefore, the marker of the present invention responds to an incident magnetic field of varying magnetic field strength by producing discontinuous generated magnetic field values in the change of magnetic flux.

The model shown in FIG. 5 shows an example in the case where the hysteresis loss of the hysteresis loop is zero. Even if the same hysteresis loop cannot be obtained, the model from the coating film (A) When a bias magnetic field is applied, the hysteresis loss of the hysteresis loop of the metal plate or the wire (B) having no magnetostriction can be regarded as substantially zero, and the hysteresis loop serves as a constant magnetic permeability portion. , If a portion having a magnetic permeability different from the constant magnetic permeability portion is also included, similarly to the above model, in the incident magnetic field in which the magnetic field strength fluctuates, the generated magnetic field discontinuous in the change of the magnetic flux of the marker. Give a value and respond.

In the metal plate or the wire (B) when the bias magnetic field from the coating film (A) is received, the hysteresis loss of the hysteresis loop is usually not 0, but the incident magnetic field 1 to 60 Hz and the magnetic field strength described later are used. Under the condition of ± 20 Oersted, the range that can be regarded as substantially 0 is, for example, more than 0 and within the range of 50 J / m ³ .

The inventor of the present invention has found that a magnetic plate having no magnetostriction or a wire (B) produces a continuous magnetic field value with respect to an incident magnetic field whose magnetic field strength fluctuates when the coating film (A) is not magnetized. Although it does not generate an output signal based on the discontinuous magnetic field value, the metal plate or the wire (B) is magnetized in a state in which the coating film (A) is magnetized at equal intervals in the longitudinal direction. Based on the knowledge that it has a constant magnetic permeability part and a magnetic permeability part different from it, we applied the phenomenon of generating an output signal based on the discontinuous magnetic field value corresponding to those inflection points to the marker detection. is there.

More specifically, in a state where the coating film (A) is not magnetized (that is, a bias magnetic field is not applied from the coating film (A) toward the metal plate or the wire (B)), The metal plate or the wire (B) having no magnetostriction gives an original hysteresis loop that the metal plate or the wire (B) has, and a continuous magnetic field value is generated in the hysteresis loop on the magnetic field H-magnetic flux density B coordinate of the metal plate or the wire (B). However, an output signal based on the discontinuous magnetic field value is not generated, but the coating film (A) is magnetized in equal portions at equal intervals in the longitudinal direction [that is, the bias magnetic field changes from the coating film (A) to In the state of being applied toward the metal plate or wire (B)], in the hysteresis loop on the magnetic field H-magnetic flux density B coordinate of the metal plate or wire (B), there are a constant magnetic permeability part and a magnetic permeability part different from it. There is By discovering that these boundaries appear as inflection points, and that they appear at least two or more, the phenomenon that generates an output signal based on the discontinuous magnetic field value corresponding to this inflection point is used as a marker. Applied to the detection of.

The marker of the present invention comprises a dry coating film (A) capable of generating a bias magnetic field formed by dispersing magnetically hard magnetic powder in a binder, a metal plate or a wire (B) having no magnetostriction. ) And a laminate having the essential structure. Specifically, for example, a dry coating film (A) capable of generating a bias magnetic field formed by dispersing magnetically hard magnetic powder in a binder is provided on one surface of a non-magnetic support and An example is a layered structure in which an adhesive layer is provided on the surface, and a metal plate having no magnetostriction or a laminate having the wire (B) fixed thereto is used as the adhesive layer. With this structure, the article that needs to be monitored can be directly attached to identify the article.

FIG. 6 shows an example of the magnetic marker of the present invention. This marker has, for example, a non-magnetic support A having a magnetic layer 1 made of a dry coating film and a magnitude of magnetostriction of 0 to 1
It can be manufactured by laminating the metal plate 2, which is a PPM, the adhesive layer 3, and the release paper 4.

Materials usable as the non-magnetic support A are:
For example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyethylene naphthalate,
Plastic film or sheet made of polyvinyl alcohol, polyester, polyethylene terephthalate, polycarbonate, nylon, polystyrene, ethylene vinyl acetate copolymer, ethylene vinyl copolymer, etc .;
Or non-magnetic metal such as aluminum; paper, impregnated paper;
Examples include composites composed of these materials, and materials other than these can be used without particular limitation as long as they have the required strength, constitution, and the like.

As the magnetic layer 1 corresponding to the dry coating film (A), for example, a magnetic layer formed by dispersing magnetic powder made of a hard magnetic material in a binder can be used.

Examples of the magnetic powder used in the present invention include ferric oxide-based ferromagnetic powders such as ferric oxide, triiron trioxide, iron oxide coated with Co, barium ferrite, strontium ferrite, and hexagonal iron oxide. Etc. Examples of the compound-based ferromagnetic powder include iron carbide and iron nitride. As the ferromagnetic metal powder, for example, the metal content in the ferromagnetic powder is 75% by weight or more, and
80% by weight or more of metal content is at least one ferromagnetic metal or alloy (for example, Fe, Co, Ni, Fe-C).
o, Fe-Ni, Co-Ni, Co-Ni-Fe), and other components (for example, Al, Si, Pb, Se, Ti, V, Cr) within the range of 20 wt% or less of this metal content. ,
Mn, Cu, B, Y, Mo, Rh, Rd, Ag, Sn,
Sb, P, Ba, Ta, W, Re, Au, Hg, S, B
Alloys containing i, La, Ce, Pr, Nd, Zn, Te) are mentioned. The ferromagnetic metal component may include a small amount of water, hydroxide or oxide. Methods for producing these ferromagnetic powders are known, and in the present invention, those produced according to known methods can be used. Above all, it is preferable to use magnetically hard magnetic powder having a saturation magnetic flux density of 70 emu / g or more.

Examples of the binder used in the magnetic layer 1 include vinyl chloride-vinyl acetate copolymers, vinyl chloride and vinyl acetate-vinyl alcohol, maleic anhydride or acrylic acid copolymers, vinyl chloride-acetic acid. Vinylidene copolymer, vinyl chloride-acrylonitrile copolymer,
Vinyl chloride copolymers such as vinyl chloride copolymers having polar groups such as sulfonic acid groups or amino groups; cellulose derivatives such as nitrocellulose; polyvinyl acetal resins; acrylic resins; polyvinyl butyral resins; epoxy resins; phenoxy resins. A polyurethane resin; a polyester polyurethane resin; a polyurethane resin having a polar group such as a sulfonic acid group and a polycarbonate polyurethane resin.

The resin used as the binder may be used alone, or may be used in combination of two or more kinds of resins such as vinyl chloride resin and polyurethane resin, cellulose derivative and polyurethane resin. it can.

The amount of the binder used is preferably in the range of 15 to 30 parts by weight per 100 parts by weight of the magnetic powder.

Examples of the dispersant used when forming the magnetic layer 1 include lecithin, higher alcohols, surfactants and the like. The amount of dispersant used is 10
The range of 0.5 to 3.0 parts by weight per 0 parts by weight is preferable.

The above-mentioned magnetic powder, binder and dispersant are
Disperse using various kneading / dispersing machines to prepare a magnetic paint. In kneading / dispersing, all of the above-mentioned components are simultaneously or individually charged into a roll-type kneader such as a two-roll or three-roll type, or a disperser such as a ball-type rotary mill.

The magnetic coating material thus produced is applied to a non-magnetic support and dried to obtain the magnetic layer 1 corresponding to the coating film (A).
The magnetic layer is formed by magnetic field orientation treatment with a permanent magnet or solenoid magnet having a magnetic field strength of 10000 Gauss, and then dried to form a magnetic layer. The magnetic field applied to the metal plate or the wire (B) is likely to be uniaxially anisotropic. It is preferable in terms. At this time, the magnetic layer may be calendered.

Examples of the method for applying the magnetic paint include air doctor coat, blade coat, rod coat, extrusion coat, air knife coat, squeeze coat, impregnation coat, reverse roll coat, transfer roll coat, gravure coat, kiss coat. , Cast coat, spray coat and the like.

The thickness of the magnetic layer 1 corresponding to the coating film (A) is
Since it is proportional to the bias magnetic field and is related to the magnitude of the anisotropy constant, the range of 5 to 100 μm can be used, and the residual magnetic flux density per unit area is 1 to 25 Mx /
The use of the cm range is preferable in that an optimum bias magnetic field can be generated.

There is a limit in increasing the thickness of the magnetic layer by the method of coating the magnetic coating on the non-magnetic support, and the thickness of 4
To obtain a magnetic layer having a thickness of 0 μm or more, for example, as shown in FIG. 7, a magnetic layer 1 is provided on a non-magnetic support A by a usual method, and an adhesive layer is further provided on the magnetic layer 1. 5, a non-magnetic support A'provided with a separately manufactured magnetic layer 1 '.
The thickness of the magnetic layer can be increased by superposing the two magnetic layers 1 and 1'to form a composite.

The adhesive used for the adhesive layer 5 is, for example, a vinyl chloride-vinyl acetate copolymer, an ethylene-vinyl acetate copolymer, a vinyl chloride-propionic acid copolymer, a rubber resin, a cyanoacrylate resin. , Cellulose resins, ionomer resins, polyolefin resins, polyurethane resins, etc., usually 0.1 to 0.5 μm.
It is formed to a thickness of m.

As a method for bonding, for example, a non-magnetic support provided with a magnetic layer is heated and pressed to bond them. Specifically, a pair of metal rolls or rubber rolls are installed facing each other, and one roll is heated,
It can be carried out by bringing it into contact with one of the non-magnetic supports B and heating and pressurizing by the pressure between the rolls and the heat of the rolls, or by using a hot press.

The heating and pressurizing conditions vary depending on the materials used, but for example, the temperature is 100 to 100 ° C.
300 ° C., about 10 kg / cm ² at a pressure thermal roll method, a hot press method 10 kg / cm ² before and after, as the speed 50m
/ Minute is appropriate.

Although not shown, a protective layer may be provided on the magnetic layer, and examples of the resin used for the protective layer include a cellulose derivative such as ethyl cellulose and cellulose acetate, a styrene resin such as polystyrene or a styrene resin. Polymerization resins, polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, acrylic resins such as butyl polyacrylate or methacrylic resin homo- or copolymer resins, polyvinyl acetate, vinyl toluene resin,
Examples thereof include vinyl chloride resin, polyester resin, polyurethane resin and butyral resin.

In order to improve wear resistance, α is added to the above resin.
A medium in which a high hardness additive such as -Al ₂ O ₃ or fine resin beads such as polytetrafluoroethylene (PTFE) is dispersed may be used.

As a method for forming the protective layer, a known coating method may be used, and examples thereof include an air doctor coat, a blade coat, a rod coat, an extrusion coat, an air knife coat, a squeeze coat, an impregnation coat and a reverse roll coat. Examples include transfer roll coat, gravure coat, kiss coat, cast coat, spray coat and the like.

A printing layer may be provided on the protective layer,
The type of the output signal, which is the value of the magnetic field generated discontinuously in the hysteresis loop generated after the magnetization of the magnetic layer 1 corresponding to the coating film (A), or the type of the article to which the marker is attached may be displayed on the printing layer. .

The material used for the adhesive layer is, for example,
Vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-propionic acid copolymer, rubber resin, cyanoacrylate resin, cellulose resin,
An ionomer resin, a polyolefin resin, a polyurethane resin, etc. may be mentioned, and they are usually formed to have a thickness of 10 to 30 μm.

As the metal having a magnitude of magnetostriction of 0 to 1 PPM, any of known and commonly used metals can be used, but a metal having a high magnetic permeability, for example, a magnetic permeability of 10 ³ to 10 ⁶ μ, as a specific commercial product. As the Co-Fe-Si-B type amorphous metal fiber "Sensy" (manufactured by Unitika Ltd.), "Metgrass 2714A", "Metgrass 2705M" (manufactured by Allied Signal Co., Ltd.) and the like can be preferably used. It is generally extremely difficult to obtain a metal whose magnetostriction is completely zero, and all of the above-mentioned commercially available products show a numerical value exceeding 0 and within the range of 1 PPM.

The magnitude of magnetostriction shown in FIG. 6 is 0 to 1 PPM.
The metal 2 has a plate shape, but is not limited thereto and may have a wire shape.

A preferred combination of the coating film (A) and the metal plate or wire (B) is a residual magnetic flux density of 1 to 25 Mx.
/ Cm and a metal plate or wire having a magnetic permeability of 10 ³ to 10 ⁶ μ in combination.

As a method for magnetizing the magnetic layer used in the present invention to generate a bias magnetic field, for example, a non-magnetic support having a magnetic layer 1 corresponding to the coating film (A) used in the present invention is used. , Metal plate or wire without magnetostriction (B)
A method may be used in which the magnetic layer 1 is magnetized with a permanent magnet or the like after being arranged in a plurality of strips at equal intervals on the above.
After stacking a non-magnetic support having the magnetic layer 1 having the same length as the metal plate or wire, the magnetizer shown in FIG. 8 and the encoder using the magnetic head shown in FIG. 9 may be used. Good.

The marker of the present invention in which a bias magnetic field is applied to the metal plate or the wire (B) from the coating film (A) has a power source and a normal power source as described in JP-A-61-153799. It can be easily detected by an electronic article monitoring device or system including a magnetic field generator having a coil, a pickup coil, and a signal detector. still,
This magnetic field generator generates an incident magnetic field (external magnetic field) different from the bias magnetic field of the coating film (A).

In such a device or system, an AC magnetic field of a predetermined frequency is generated by, for example, a magnetic field generator and is applied to a region to be detected,
An incident magnetic field is provided. The marker of the present invention in which the bias magnetic field is emitted from the coating film (A) toward the metal plate or the wire (B) generates an output signal according to the above-mentioned principle when entering the incident magnetic field. By capturing with the pickup coil and detecting the output signal with the signal detector, it becomes possible to identify various kinds of articles that need to be monitored accompanying the marker.

The incident magnetic field used for detecting the marker of the present invention is usually an alternating magnetic field, specifically, an alternating magnetic field having a frequency in the range of 1 to 60 Hz, and is about 20 at a weak detection area.
A specific constant value of the predetermined frequency is selected so that the amplitude is as large as or more than Oersted. The larger the amplitude, the more clearly the presence of the marker can be grasped. As the alternating magnetic field, for example, a sine wave or a triangular wave is used.

In detecting the marker, the intensity of the incident magnetic field provided at the selected predetermined frequency is changed. In changing the intensity, the intensity of the frequency is changed between the positive amplitude intensity value and the negative value of the predetermined frequency having the largest amplitude as described above, and the existence of the marker is grasped. When an AC magnetic field with a frequency in the range of 1 to 60 Hz is used and the maximum amplitude is 20 Oersted, the strength is changed from positive to negative or from negative to positive in the range of -20 to +20 Oersted. You can do it.

In the present invention, the most suitable combination (system) of the magnetic marker and its detecting device uses a dry coating film having a residual magnetic flux density of 1 to 25 Mx / cm and has no magnetostriction.
Within the range of 1 PPM and having a magnetic permeability of 10 ³ or more, and by laminating in combination with a metal plate or a wire, a constant magnetic permeability portion and a different magnetic permeability portion are developed when the coating film is magnetized. Configure a magnetic marker to
An incident AC magnetic field, which has a predetermined frequency selected from 60 Hz and whose strength fluctuates in the range of −20 to +20 Oersted, which is larger than the bias magnetic field, is provided in advance, and the inflection between the constant magnetic permeability portion and the magnetic permeability portion different from that. The point is detected as a discontinuous magnetic field value.

By the way, in the marker of the present invention, since the coating film (A) is magnetized into equal portions at equal intervals, the number of divisions (the number of divisions) when the coating film of each marker is magnetized. For example, if the value is changed in the range of 2 to 20, an output signal based on two or more discontinuously generated magnetic field values of different specific kinds according to the equal fraction is generated. Can be identified.

[0064]

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

(Preparation Example of Magnetic Coating Material) 100 parts by weight of metal magnetic powder "HJ-8" [manufactured by Dowa Mining Co., Ltd.] having coercive force of 1550 oersted (Oe) and saturation magnetic flux density of 120 emu / g, lecithin 3 parts by weight, Vinyl chloride-vinyl acetate-vinyl alcohol copolymer "VAGH" (manufactured by United States Union Carbide) 10 parts by weight, polyurethane elastomer "T-5206" (manufactured by Dainippon Ink and Chemicals, Inc.) 1
0 part by weight was kneaded with a kneader, 300 parts by weight of an equal weight mixture of methyl ethyl ketone, toluene, and cyclohexanone was added to the obtained kneaded product, which was dispersed by a ball mill to obtain a magnetic coating material.

Example 1 The magnetic coating material obtained in the preparation example of the magnetic coating material was applied onto the surface of a polyester film having a thickness of 24 μm so that the coating thickness after drying was 15 μm.
A magnetic field orientation of 000 gauss was applied and dried to obtain a non-magnetic support having a magnetic layer. Two non-magnetic supports having this magnetic layer are attached with a magnetic layer inside by an adhesive layer (polyurethane elastomer “T-5206” manufactured by Dainippon Ink and Chemicals, Inc.) having a thickness of 0.5 μm. After
A strip having a width of 10 mm and a length of 100 mm was cut out along the alignment direction to obtain a base material having a total thickness of 30 μm and a magnetic layer thickness of 78.5 μm.

Then, as shown in FIG. 9, the magnetic layer of this base material is magnetized and written so as to divide 100 mm in the longitudinal direction into four equal parts (that is, at intervals of 25 mm), as shown in FIG. It was done and magnetized.

In order to obtain a metal plate having a magnetostriction of 0 to 1 PPM (catalog value) as shown in FIG.
"Metgrass 2714A" (25 microns thick) is 2 wide
mm, cut out into a stripe with a length of 100 mm, and
The marker of the present invention was produced by stacking and fixing the substrate having the magnetic layer.

Further, with respect to the case where the marker of Example 1 was magnetized as shown in FIG. 1, the hysteresis curve was measured when an alternating magnetic field with a magnetic field strength of 20 Oersted and a frequency of 30 Hz was applied. The value of the continuous magnetic field generated was determined. The measurement results are shown in FIG. 10 and Table 1.

Further, an alternating magnetic field having a magnetic field strength of 20 Oersted and a frequency of 30 Hz was applied to the marker of Example 1, and a specific output voltage which generated a discontinuous generated magnetic field value in the hysteresis loop with respect to time change was measured, The results are shown in Fig. 11.

(Embodiment 2) In Embodiment 1, a normal magnetic encoder is used to magnetize and write so that 100 mm in the longitudinal direction is divided into 7 equal parts (that is, 14.285 mm intervals). The markers of the present invention were prepared in the same manner as in Example 1 except for the above, and the measurement results are shown in Table 1 and FIGS. 12 and 13.

(Embodiment 3) In Embodiment 1, except for using a normal magnetic encoder and magnetizing by writing so that 100 mm in the longitudinal direction is divided into 16 equal parts (that is, 6.25 mm intervals). The marker of the present invention was prepared in the same manner as in Example 1, and the measurement results are shown in Table 1 and FIGS.

Example 4 In Example 1, the magnetic coating material obtained in the preparation example of magnetic coating material was applied onto a polyester film having a thickness of 24 μm so that the film thickness after drying was 6 μm. After obtaining a substrate having a total magnetic layer thickness of 12 μm and a total thickness of 60.5 μm in the same manner as in Example 1,
The marker of the present invention was prepared in the same manner as in, and the measurement results are shown in Table 1 and FIG.

(Example 5) In Example 1, the magnetic coating material obtained in the preparation example of the magnetic coating material was applied on a polyester film having a thickness of 24 µm so that the film thickness after drying would be 20 µm. After obtaining a base material having a total magnetic layer thickness of 40 μm and a total thickness of 88.5 μm, the marker of the present invention was prepared in the same manner as in Example 1, and the measurement results are shown in Table 1 and FIG. I'm sorry.

[0075]

[Table 1]

In Table 1, the values of the first discontinuously generated magnetic field and the second discontinuously generated magnetic field in the upper row show the inflection points of the hysteresis curve in FIG. Further, the number of divisions means, as shown in FIG. 9, how many magnetic layers having a length of 100 mm of the base material are magnetized and divided at equal intervals, that is, the number obtained by dividing the magnetic layers at equal intervals. .

Each of the markers of Examples 1 to 5 could be repeatedly written.

In order to make Table 1 more understandable, Table 1
18 shows the relationship between the number of divisions in Examples 1 to 3 and the values of the first and second discontinuously generated magnetic fields in the thickness of the magnetic layer 30 μ in FIG.
It was shown to. In addition, the thickness of the magnetic layer of Examples 1, 4, 5 and 4
The relationship between the first and second discontinuously generated magnetic field values in division is shown in FIG.

The following can be seen from FIGS. 18 and 19. That is, as the number of recording divisions of the magnetic layer is increased,
The first and second discontinuously generated magnetic field values increase proportionally,
Further, as the film thickness of the magnetic layer is increased, the first and second discontinuity generated magnetic field values are proportionally increased. Therefore, by determining the film thickness of the magnetic layer and the number of recording divisions of the magnetic layer, the first and second discontinuous magnetic field values peculiar to each magnetic marker can be obtained.

On the other hand, in the conventional magnetic marker, since the magnetic layer for applying the bias magnetic field is not magnetized to a large extent, the presence or absence of the article to which the marker is attached can be detected. Cannot be identified.

In the marker of the present invention, since the coating type magnetic layer is used, the marker having high workability and having the adhesive property can be directly attached to the article to be detected. Further, when the external magnetic field applied to the marker is sufficiently smaller than the magnitude of the bias magnetic field, the energy change is small with respect to the external magnetic field change. Considering that the metal plate or the wire used in the present invention does not have a bias magnetic field, a harmonic is generated or a pulse signal of the large Barkhausen effect is generated with respect to an external AC magnetic field. It can also be applied to.

[0082]

The magnetic marker of the present invention is a marker having a structure in which a dry coating film formed by dispersing magnetic powder made of a hard magnetic material in a binder and a magnetostrictive metal plate or wire are laminated. However, since the coating film is equally divided in the longitudinal direction at equal intervals, not only the presence / absence of an article to be monitored but also a large number of articles can be individually identified, which is a remarkable effect.

[0083]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a high-permeability metal stripe having a magnitude of magnetostriction of 0 to 1 PPM under a bias magnetic field from magnetic layers magnetized at equal intervals.

FIG. 2 is a schematic diagram illustrating a magnetic moment of a metal stripe when a magnitude of an applied external magnetic field is smaller than a bias magnetic field in the composition of the present invention.

FIG. 3 is a schematic diagram illustrating a magnetic moment of a metal stripe when a magnitude of an applied external magnetic field is larger than a bias magnetic field in the composition of the present invention.

FIG. 4 is a schematic diagram illustrating a magnetic moment when viewed as the entire metal stripe when the magnitude of an applied external magnetic field is larger than the bias magnetic field in the structure of the present invention.

FIG. 5 is an example of a hysteresis curve generated by the marker of the present invention with respect to a low frequency alternating magnetic field.

FIG. 6 is a schematic cross-sectional view showing an example of the marker of the present invention.

FIG. 7 is a schematic diagram illustrating a case where the thickness of the magnetic layer in the laminate used in the present invention is increased.

FIG. 8 is an example of a schematic view showing a method of magnetizing the marker of the present invention.

FIG. 9 is an example of a schematic view showing a method of magnetizing the marker of the present invention.

10 is a graph showing the results of measuring a hysteresis curve in Example 1. FIG.

FIG. 11 is a graph showing a result of measuring a peculiar output voltage generated by a discontinuous generated magnetic field value with respect to time change in the first embodiment.

FIG. 12 is a graph showing the results of measuring a hysteresis curve in Example 2.

FIG. 13 is a graph showing a result of measuring a peculiar output voltage generated by a discontinuous generated magnetic field value with respect to time change in the second embodiment.

FIG. 14 is a graph showing a result of measuring a hysteresis curve in Example 3.

FIG. 15 is a graph showing a result of measuring a peculiar output voltage generated by a discontinuous generated magnetic field value with respect to time change in the third embodiment.

16 is a graph showing the results of measuring a hysteresis curve in Example 4. FIG.

FIG. 17 is a graph showing the results of measuring the hysteresis curve in Example 5.

FIG. 18 is a diagram showing a relationship between the number of divisions of Examples 1 to 3 in Table 1 and the first and second discontinuously generated magnetic field values in the thickness of the magnetic layer 30 μ.

FIG. 19 is a diagram showing the relationship between the thickness of the magnetic layer and the first and second discontinuously generated magnetic field values in four divisions in Examples 1, 4, and 5.

[Explanation of symbols]

A non-magnetic support 1 magnetic layer 2 high-permeability metal stripe or wire having a magnetostriction magnitude of 0 to 1 PPM 3 adhesive layer 4 release paper 5 adhesive layer

Claims (6)

[Claims] 1. A magnetic field strength comprising a laminate of a dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder and a metal plate or a wire (B) having no magnetostriction. In the state where the coating film (A) is not magnetized with respect to the incident magnetic field that fluctuates, the metal plate or the wire (B) generates a continuous magnetic field value and outputs an output signal based on the discontinuous magnetic field value. Although not generated, in the state where the coating film (A) is magnetized at equal intervals in the longitudinal direction, the metal plate or the wire (B) has a constant magnetic permeability portion and a constant magnetic permeability portion. A magnetic marker having different magnetic permeability parts, wherein an output signal based on a discontinuous magnetic field value is generated based on the difference in the magnetic permeability, and the magnetic marker responds to the incident magnetic field. .. 2. A metal plate or wire (B) in a state where the coating film (A) is magnetized has a magnetic flux density B which is linear with respect to a magnetic field H in its hysteresis loop, and a magnetic permeability which is equal to that of an incident magnetic field H. The marker according to claim 1, which is a metal plate or a wire that exhibits a constant property independent of the size. 3. The dry coating film (A) has a residual magnetic flux density of 1 to 25.
Mx / cm and the metal plate or wire (B) is 0
The marker according to claim 1, wherein the marker is a metal plate or a wire having a magnetostriction of 1 PPM exceeding the range. 4. The dry coating film (A) has a residual magnetic flux density of 1 to 25.
Mx / cm, the metal plate or wire (B) has a magnetostriction exceeding 0 and within the range of 1 PPM, and the coating film (A) is magnetized. ), The magnetic flux density B is linear with respect to the magnetic field H, and its hysteresis loss is caused by an incident AC magnetic field having an intensity of −20 to +20 Oersted at a predetermined frequency of 1 to 60 Hz which is set in advance. Is a value exceeding 0 and within the range of 50 J / m ³ , The marker according to claim 1. 5. A magnetic field strength comprising a laminate of a dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder and a magnetostrictive metal plate or wire (B). In the state in which the coating film (A) is not magnetized with respect to the incident magnetic field that fluctuates, the metal plate or the wire (B) has a continuous magnetic field value in the hysteresis loop on the magnetic field H-magnetic flux density B coordinate. Although it does not generate an output signal based on the discontinuous magnetic field value, the metal plate or the wire (B) is in a state in which the coating film (A) is magnetized at equal intervals in the longitudinal direction. An output signal based on a discontinuous magnetic field value is obtained by exhibiting a constant magnetic permeability and having at least two inflection points in the hysteresis loop on the magnetic field H-magnetic flux density B coordinate of the metal plate or wire (B). Generated and respond to the incident magnetic field Magnetic markers characterized in that the. 6. A dry coating film (A) formed by dispersing magnetically hard magnetic powder in a binder on one surface of a non-magnetic support, and an adhesive layer on the other surface thereof. It consists of a metal plate having no magnetostriction with an adhesive layer or a laminated body to which the wire (B) is fixed, and in the state where the coating film (A) is not magnetized to the incident magnetic field whose magnetic field strength fluctuates, the metal plate or The wire (B) generates a continuous magnetic field value in the hysteresis loop on the magnetic field H-magnetic flux density B coordinate and does not generate an output signal based on the discontinuous magnetic field value, but the coating film (A) is in the longitudinal direction. In the state in which the metal plate or wire (B) is magnetized at equal intervals, the metal plate or wire (B) exhibits a constant magnetic permeability, and the magnetic field H of the metal plate or wire (B) -the hysteresis loop on the B coordinate of the magnetic flux density. By having at least two inflection points in Magnetic markers to generate an output signal based the connection of the magnetic field values, characterized in that the manner in response to the incident magnetic field.