JPH0744779A - Marker for electronic article monitoring system - Google Patents

Abstract

PURPOSE:To reduce production cost, and to improve workability, and to stabilize residual magnetic flux by providing a nonmagnetic supporting body with a magnetic layer in which the magnetic powder of specified saturation magnetic flux density is dispersed on its face of one side, and providing the same with the metal of a specified generation magnetic field value on its face of the other side. CONSTITUTION:The nonmagnetic supporting body B is provided with the magnetic layer 1 in which the magnetic powder of the saturation magnetic flux density over 70emu/g is dispersed in binder on its face of one side. The metal 6 which holds the generation magnetic field value of large Barkhausen discontinuity in a magnetic hysteresis loop as a component to generate an output signal in response to incident magnetic energy, an adhesive layer 4, and a peeling layer 5 are laminated on its face of the other side. Since the purpose of the magnetic layer 1 is to make the size of magnetic field strength in the distance of the thickness of the nonmagnetic supporing body B equal to the size of the magnetic field strength conventional hard magnetic material has, it is desirable that the saturation magnetic flux density of the magnetic powder in the magnetic layer 1 is over 70emu/g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetically sensitive marker, and more particularly to a marker for an electronic article surveillance system that emits a specific signal within an interrogation region of incident magnetic energy.

[0002]

2. Description of the Related Art As a marker for an electronic article monitoring device,
It is common to use high permeability materials with low coercive force,
It was first disclosed in French Patent No. 763,681 in 1934. After that, US Pat. No. 366554
No. 9, U.S. Pat. No. 3,747,086, and U.S. Pat. No. 3,790,945 disclose that a magnetic field generated by the magnetization of a hard magnetic material has a low coercive force by combining a low coercive force high permeability material and a hard magnetic material. Markers have been described which act on a magnetically permeable material as a bias magnetic field to alter the signal produced when present in the interrogation region.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent Laid-Open No. 8-250299 and Japanese Patent Laid-Open No. 3-250299, an adhesive layer is generally provided on a base material such as paper, and a hard magnetic material of a predetermined size is stuck on the adhesive layer, and the hard magnetic material is used. There is described a marker in which an adhesive layer is provided on a material, a high-permeability material having a predetermined size is attached onto the adhesive layer, and an adhesive layer is provided on the high-permeability material. However, there is a problem that the number of production steps is large and the production cost is high.

The hard magnetic materials used in these are
It is a metal ribbon of a ferromagnetic alloy such as SAE1095 steel, Vicalloy, Remalloy, Arnochrome, and Clovac. The metal ribbon has problems that it is fragile, has low anisotropy, and has poor workability.

Further, Japanese Patent Application Laid-Open No. 63-83899 discloses a method of directly coating magnetizable particles in an organic binder on a high magnetic permeability material.

In the above-mentioned method of coating magnetizable particles directly dispersed in an organic binder on the high magnetic permeability material, the adhesion to the high magnetic permeability material is poor, and the base material is the high magnetic permeability material. However, there is a problem that the residual magnetic flux is not stable because the magnetic field cannot be uniformly oriented.

An object of the present invention is to provide a marker for monitoring electronic articles, which has a low production cost, high workability, and stable residual magnetic flux.

[0008]

The present inventor has accomplished the present invention as a result of extensive studies in order to solve the above problems.

That is, in order to solve the above problems, the present invention has a magnetic layer having, on one surface of a non-magnetic support, magnetic powder having a saturation magnetic flux density of 70 emu / g or more dispersed in a binder. For an electronic article surveillance system, the other surface has a metal that has a magnetic field value of a large Barkhausen discontinuity in a magnetic hysteresis loop as a component that generates an output signal in response to incident magnetic energy. Provide a marker.

In the present invention, the large Barkhausen effect in the magnetic hysteresis loop means that when the external excitation magnetic field in the fiber axis direction of a metal exceeds a certain threshold value, a reverse magnetic domain is formed in the metal. At the same time, it is a phenomenon in which the domain wall instantaneously moves and the reversal of the magnetization of the metal ends, and this abrupt reversal of magnetization is called the large Barkhausen effect, and even if the exciting magnetic field exceeds the threshold level peculiar to each metal. Then, a rapid reversal of the magnetization occurs regardless of the rate of change of the exciting magnetic field.

FIG. 3 shows an example of the marker for the electronic article monitoring system of the present invention. This marker can be produced, for example, by laminating a non-magnetic support having a magnetic layer with a metal having a generated magnetic field value of large Barkhausen discontinuity in a magnetic hysteresis loop, an adhesive layer, and a release paper. it can.

Materials usable as the non-magnetic support include, 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.

The magnetic layer is intended to make the magnitude of the magnetic field strength at the distance of the thickness of the non-magnetic support the same as the magnitude of the magnetic field strength of the conventional hard magnetic material.
The saturation magnetic flux density of the magnetic powder in the magnetic layer is preferably 70 emu / g or more, particularly preferably 90 emu / g or more.

Examples of the magnetic powder include ferric oxide, ferric tetroxide, iron oxide coated with Co, barium ferrite, strontium ferrite, and hexagonal iron oxide as iron oxide-based ferromagnetic powder. . Examples of the compound-based ferromagnetic powder include iron carbide and iron nitride.
As the ferromagnetic metal powder, the metal content in the ferromagnetic powder is 75% by weight or more, and 80% by weight or more of the metal content is at least one type of ferromagnetic metal or alloy (for example, Fe, Co, Ni, Fe-Co, Fe-Ni, Co
-Ni, Co-Ni-Fe), and this metal content is 20
Within the range of not more than wt%, other components (for example, Al, Si,
Pb, Se, Ti, V, Cr, Mn, Cu, B, Y, M
o, Rh, Rd, Ag, Sn, Sb, P, Ba, Ta,
W, Re, Au, Hg, S, Bi, La, Ce, Pr,
Examples include alloys containing Nd, Zn, Te). 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.

As the binder used in the magnetic layer, for example, vinyl chloride-vinyl acetate copolymer, vinyl chloride and vinyl acetate and vinyl alcohol, maleic anhydride or acrylic acid copolymer, vinyl chloride-vinylidene acetate. 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 in the magnetic layer include lecithin, higher alcohols and surfactants. The amount of the dispersant used is preferably in the range of 0.5 to 3.0 parts by weight per 100 parts by weight of the magnetic powder.

The magnetic powder, binder, and dispersant described above 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 thus prepared is applied to a non-magnetic support, subjected to a magnetic field orientation treatment by a permanent magnet or a solenoid magnet having a magnetic field strength of 1000 to 10000 gauss, and then dried to form a magnetic layer. To do. At this time, the magnetic layer may be calendered.

The magnetic coating material can be applied, for example, by air doctor coating, blade coating, rod coating, extrusion coating, air knife coating, squeeze coating, impregnation coating, reverse roll coating, transfer roll coating, gravure coating, kiss coating. , Cast coat, spray coat and the like.

The thickness of the magnetic layer is preferably in the range of 5 to 100 μm, and the residual magnetic flux density per unit area is 1 to 25 Mx.
It is desirable to be in the range of / cm.

There is a limit to increase the thickness of the magnetic layer by the method of coating the magnetic coating on the non-magnetic support, and the thickness of the magnetic layer is 4
In order to obtain a magnetic layer having a thickness of 0 μm or more, for example, as shown in FIG. 2, a magnetic layer 1 is provided on a non-magnetic support B by a usual method, and an adhesive layer is further provided on the magnetic layer 1. 3, a non-magnetic support B'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.

In such a case, one nonmagnetic support B'can be used as the protective layer 2 shown in FIG.

The adhesive used in the adhesive layer 3 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 of 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 material used, but as an example, the temperature is from 100 to
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.

The thickness of the magnetic layer provided on the non-magnetic support is related to the thickness of the non-magnetic support. In order to show the relationship, when the thickness of the magnetic layer having the same characteristics as the ribbon of the hard magnetic material having a thickness of 40 to 60 μm used in the prior art and the residual magnetic flux density thereof are viewed from the non-magnetic support side. The preferred range for the thickness of the non-magnetic support is shown in Table 1 below.

[0029]

[Table 1]

A protective layer may be provided on the magnetic layer. Examples of the resin used for the protective layer include cellulose derivatives such as ethyl cellulose and cellulose acetate, styrene resins such as polystyrene or styrene copolymer resins, and polymethacrylic acid. Acrylic resin or methacrylic resin such as methyl, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate, homopolymer or copolymer resin, polyvinyl acetate, vinyltoluene resin, vinyl chloride resin, polyester resin, polyurethane resin, butyral resin Etc.

In order to improve wear resistance, α is included in 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 the method for forming the protective layer, known coating methods may be used, and examples thereof include air doctor coat, blade coat, rod coat, extrusion coat, air knife coat, squeeze coat, impregnation coat, 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 from the metal having the generated magnetic field value of the large Barkhausen discontinuity in the magnetic hysteresis loop or the type of the article to which the marker is attached may be displayed on the printed 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, and the like can be given, and they are usually formed to have a thickness of 0.1 to 0.5 μm.

The large Barkhausen discontinuity in the magnetic hysteresis loop is the demagnetization of the magnetic layer, zero bias field, and as a component to generate an output signal in the associated electronic article surveillance system in response to incident magnetic energy. Examples of the metal material that retains the generated magnetic field value include:
Fe-Si-B amorphous metal fiber "Sensy"
(Manufactured by Unitika Ltd.) or “Metgrass 2605CO” (manufactured by Allied Signal Co.) which has been subjected to an annealing treatment at 300 ° C. for 1 hour.

The shape of the metal 6 having the generated magnetic field value of the large Barkhausen discontinuity in the magnetic hysteresis loop shown in FIG. 1 is a ribbon shape, but the shape is not limited to this and may be a plate shape or a wire shape. May be.

As shown in FIG. 3, the marker for an electronic article monitoring system of the present invention has a non-magnetic support having a magnetic layer, which has a magnetic field value of large Barkhausen discontinuity in a magnetic hysteresis loop. A configuration may be used in which a non-magnetic housing 8 that houses the metal 6 is provided. In this structure, an output pulse is easily generated from the metal 6 in response to the incident magnetic energy.

Materials that can be used as the non-magnetic casing 8 are, for example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyethylene naphthalate,
Polyvinyl alcohol, polyethylene terephthalate,
Plastics made of polycarbonate, nylon, polyester, polystyrene, ethylene vinyl acetate copolymer, ethylene vinyl copolymer, etc .; or non-magnetic metal such as aluminum; paper, impregnated paper; composites made of these materials, Even materials other than these can be used without particular limitation as long as they have the required strength, structure, and the like.

The coupling between the non-magnetic support B and the non-magnetic casing 8 is
The contact portions are formed into a composite shape that can be integrated, or an adhesive is used.

Examples of the adhesive include vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-propionic acid copolymer, rubber resin,
Examples include cyanoacrylate resin, cellulose resin, ionomer resin, polyolefin resin, polyurethane resin, and the like, and the adhesive layer is usually formed to a thickness of 0.1 to 0.5 μm.

Further, although not shown in FIG. 1, the magnetic layer 1 is formed directly on the surface of the metal 6 having the generated magnetic field value of the large Barkhausen discontinuity in the magnetic hysteresis loop, and the nonmagnetic support is formed thereon. The body B may be provided. Further, in FIG. 2, the metal may be sandwiched between the adhesive layer 3 and the magnetic layer 1.

As a method of magnetizing the magnetic layer used in the present invention to generate a bias magnetic field, for example, a non-magnetic support having the magnetic layer used in the present invention is used, and a large Barkhausen defect in a magnetic hysteresis loop is used. A method of arranging a plurality of strips at regular intervals on a metal ribbon or wire having a continuous magnetic field value and then magnetizing the magnetic layer with a permanent magnet or the like is used. A non-magnetic support having the magnetic layer of the same length as the ribbon or wire of FIG.
The encoder shown in FIG. 5 may be used.

FIG. 6 shows the magnetized state of the magnetic layer used in the present invention, and FIG. 7 shows its demagnetized state.

The marker of the present invention is disclosed in JP-A-61-153.
A magnetic field generator having a power supply and a normal coil, a pickup coil, as described in Japanese Patent Publication No. 799, etc.
And easily detected by an electronic article surveillance device or system comprising a signal detector. In such a device or system, an alternating magnetic field having a predetermined frequency is generated by the magnetic field generator and applied to the interrogation area, and the output signal of the marker of the present invention is captured by the pickup coil and the output signal is detected by the signal detector. . The AC magnetic field used is usually an AC magnetic field with a frequency in the range of 10 to 10000 Hz, and has an amplitude of about 20 Oersted at a strong interrogation area and an amplitude of 1 Oersted or less at a weak interrogation region. Various improvements have been made in this field in order to improve reliability, and these methods are well known to all persons skilled in the art and need not be further described here.

[0045]

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

(Preparation Example of Magnetic Paint) Average particle size 0.4 μm
m, coercive force 680 oersted, saturation magnetic flux density 120em
u / g metal magnetic powder "MAP-L" (manufactured by Kanto Denka Kogyo KK) 100 parts by weight, lecithin 3 parts by weight, vinyl chloride-vinyl acetate-vinyl alcohol copolymer "VAG"
10 parts by weight of "H" (manufactured by Union Carbide Co., USA) and 10 parts by weight of polyurethane elastomer "T-5206" (manufactured by Dainippon Ink and Chemicals, Inc.) are kneaded in 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 and 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 coated on the surface of a polyester film having a thickness of 50 µm so that the coating thickness after drying was 30 µm.
After applying a magnetic field orientation of 000 gauss and drying, width 10m
A non-magnetic support having a magnetic layer with a thickness of 30 μm was obtained by cutting a strip having a length of m and a length of 50.8 mm along the alignment direction. The magnetostatic characteristics of the obtained magnetic layer were measured, and the results are shown in Table 2.

Then, this magnetic layer was magnetized at an interval of 25.4 mm as shown in FIG. 6 by using an ordinary magnetizer, and then 190 by using a magnetic head having a gap of 20 μm.
The results are shown in Table 2 as a substitute characteristic of the magnetic field strength which becomes the bias magnetic field by running the striped magnetic layer in the longitudinal direction at the polyester film side at mm / sec and measuring the reproduction output.

Further, as shown in FIG. 1, in order to make a metal having a generated magnetic field value of large Barkhausen discontinuity in the magnetic hysteresis loop, "Methograss 2605CO" is cut out in a ribbon shape having a width of 2 mm and a length of 50 mm. , 30
After performing the annealing treatment at 0 ° C. for 1 hour,
The marker of the present invention was produced by superimposing it on a non-magnetic support having a striped magnetic layer.

Further, the marker of Example 1 was magnetized as shown in FIGS. 6 and 7 and was demagnetized, and the magnetic field strength was 3.0 oersted and the frequency was 3, respectively.
The hysteresis curve was measured when an AC magnetic field of 0 Hz was applied. The measurement results are shown in FIGS. Furthermore, an AC magnetic field having a magnetic field strength of 3.0 oersted and a frequency of 30 Hz was applied to the marker of Example 1, and the pulse output voltage generated by the magnetization reversal that the generated magnetic field value of the large Barkhausen discontinuity with respect to the time change was generated. The measurement was performed, and the results are shown in FIGS.

Example 2 The same as Example 1 except that the nonmagnetic support having the magnetic layer shown below was used in place of the nonmagnetic support having the magnetic layer. The marker of the present invention was produced.

That is, the magnetic coating material obtained in the preparation example of the magnetic coating material was applied on the surface of a polyester film having a thickness of 50 μm so that the film thickness after drying would be 40 μm, and then 5000
It was dried while applying a Gaussian magnetic field orientation to obtain a non-magnetic support having a magnetic layer. Separately, it was coated on a polyester film having a thickness of 24 μm so that the film thickness after drying was 20 μm, and then dried while applying a magnetic field orientation of 5000 Gauss to obtain a non-magnetic support having a magnetic layer. A non-magnetic support having these two types of magnetic layers, with the magnetic layer inside, an adhesive layer having a thickness of 0.5 μm (polyurethane elastomer “T-520 manufactured by Dainippon Ink and Chemicals, Inc.”
6 ”) to obtain a non-magnetic support having a magnetic layer having a thickness of 60 μm.

Table 2 shows the results of measurement in the same manner as in Example 1 regarding the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse when the marker of the present invention was magnetized and demagnetized.

(Example 3) In Example 2, the thickness 50
100 μm thickness instead of μm polyester film
Using the above polyester film, the magnetic coating material obtained in the preparation example of the magnetic coating material was applied onto a polyester film having a thickness of 24 μm so that the film thickness after drying would be 20 μm, and the same thickness as in Example 2 was applied. After obtaining a non-magnetic support having a 60 μm magnetic layer, the marker of the present invention was produced in the same manner as in Example 1.

Table 2 shows the results of measurement in the same manner as in Example 1 regarding the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse when the marker of the present invention was magnetized and demagnetized.

(Example 4) In Example 2, the thickness 50
100 μm thickness instead of μm polyester film
Using the above polyester film, the magnetic coating material obtained in the preparation example of the magnetic coating material was applied onto a polyester film having a thickness of 24 μm so that the film thickness after drying would be 40 μm, and the same thickness as in Example 2 was applied. After obtaining a non-magnetic support having a magnetic layer of 80 μm, the marker of the present invention was produced in the same manner as in Example 1.

In the same manner as in Example 1, Table 2 shows the results obtained by measuring the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse when the marker of the present invention was magnetized and demagnetized.

(Embodiment 5) In Embodiment 1, as the magnetic powder, coercive force is 1550 oersted, saturation magnetic flux density is 12
After obtaining a non-magnetic support having a magnetic layer with a thickness of 30 μm in the same manner as in Example 1 except that the magnetic magnetic powder “HJ-8” of 0 emu / g (manufactured by Dowa Mining Co., Ltd.) was used. The marker of the present invention was prepared in the same manner as in Example 1.

In the same manner as in Example 1, the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse at the time of magnetization and demagnetization of the marker of the present invention are shown in Table 2.

(Example 6) The magnetic powder used in Example 5 was used, and in Example 2, it was coated on a polyester film having a thickness of 24 µm so that the film thickness after drying was 20 µm. After a non-magnetic support having a magnetic layer with a thickness of 60 μm was obtained in the same manner as in, the marker of the present invention was produced in the same manner as in Example 1.

Table 2 shows the results of measurement in the same manner as in Example 1 regarding the magnetostatic properties of the magnetic layer, the reproduction output, and the presence / absence of a pulse during magnetization and demagnetization of the marker of the present invention.

Example 7 Using the magnetic powder used in Example 5, a nonmagnetic support having a magnetic layer of 60 μm in thickness was obtained in the same manner as in Example 3, and then the marker of the present invention was used. It was made.

Table 2 shows the results of measurement in the same manner as in Example 1 regarding the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse during magnetization and demagnetization of the marker of the present invention.

Example 8 The magnetic powder used in Example 5 was used to obtain a non-magnetic support having a magnetic layer having a thickness of 80 μm in the same manner as in Example 4, and then the marker of the present invention was used. It was made.

Table 2 shows the results of measurement in the same manner as in Example 1 regarding the magnetostatic characteristics of the magnetic layer, the reproduction output, and the presence / absence of a pulse upon magnetization and demagnetization of the marker of the present invention.

Comparative Example 1 Instead of the magnetic layer, a width of 10 mm,
A metal ribbon "VACOZET" (made by Vacuumshmeltz) having a length of 50.8 mm and a thickness of 60 µm and made of a hard magnetic material is fixed with "cellophane tape" (cellophane adhesive tape made by Nichiban Co., Ltd.), Others were the same as in Example 1 to prepare a marker.

In the same manner as in Example 1, the magnetostatic characteristics of the metal ribbon of the hard magnetic material, the reproduction output, and the presence / absence of a pulse at the time of magnetizing and demagnetizing the produced marker are shown in Table 2. .

(Comparative Example 2) A marker was prepared in the same manner as in Comparative Example 1 except that a polyester film having a thickness of 100 μm was used.

In the same manner as in Example 1, the results obtained by measuring the magnetostatic characteristics of the metal ribbon of the hard magnetic material, the reproduction output, and the presence / absence of a pulse during magnetization and demagnetization of the produced marker are shown in Table 2. .

As shown in FIG. 8, in Example 1, when the magnetic layer was demagnetized and a bias magnetic field was not applied,
A metal having a generated magnetic field value of large Barkhausen discontinuity in the magnetic hysteresis loop retains the generated value. Therefore, the pulse output confirmed in FIG. 10 is generated. A bias magnetic field is generated by magnetizing the magnetic layer used in the present invention, and the magnetic hysteresis loop changes linearly as shown in FIG. Therefore, as shown in FIG. 11, no pulse output is generated.

[0071]

[Table 2]

In Table 2, "magnetization" in the upper right column indicates the case where the magnetic layer is magnetized, and "demagnetization" indicates the case where the magnetic layer is demagnetized. Further, in the upper item, the higher the value of “reproduction output”, the stronger the magnetic force. The “squareness ratio” indicates anisotropy of magnetic flux in the longitudinal direction of the stripe-shaped magnetic layer.
The value described in the column of magnetic layer thickness in Comparative Examples 1 and 2 indicates the thickness of the metal ribbon of the hard magnetic material.

From Table 2, the following can be seen. That is, comparing Example 1 and Example 5, the thickness of the magnetic layer is the same and the coercive force is different, but the residual magnetic flux is the same and the reproduction output is also the same. Similarly, for example, comparing Example 2 and Example 6, the magnetic layers have the same thickness and the coercive force is different, but the residual magnetic flux is the same and the reproduction output is almost the same.

Therefore, it is clear from Table 2 that the reproduction output as a substitute characteristic of the bias magnetic field depends on the residual magnetic flux regardless of the coercive force.

Regarding the squareness ratio, as can be seen from the comparison between Example 1 or Example 5 and Comparative Example 1 or 2, the magnetic layer used in the present invention is thinner than the conventional ribbon-shaped hard magnetic material. However, a high magnetic force can be obtained depending on the orientation. The strong anisotropy shown in the examples cannot be obtained by the conventional ribbon-shaped hard magnetic material.

[0076]

Since the marker of the present invention uses the magnetic layer in which magnetic powder is dispersed in the binder, it has high processability and shortens the manufacturing process. Furthermore, the marker according to claim 3 can be attached to an article to be detected, and the marker according to claim 4 can be attached to an article to be detected.

[0077]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a marker for an electronic article monitoring system of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a method of increasing the thickness of a magnetic layer used in the marker for an electronic article monitoring system of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of a marker for an electronic article monitoring system of the present invention.

FIG. 4 is a schematic diagram showing a magnetizer.

FIG. 5 is a schematic diagram showing an encoder.

FIG. 6 is a schematic cross-sectional view of a main part showing a case where a magnetic layer used in a marker for an electronic article monitoring system of the present invention is magnetized.

FIG. 7 is a schematic cross-sectional view of a main part showing a case where a magnetic layer used in the marker for an electronic article monitoring system of the present invention is demagnetized.

FIG. 8 is a table showing a hysteresis curve when the magnetic layer used in the marker for the electronic article monitoring system of the present invention is demagnetized.

FIG. 9 is a table showing a hysteresis curve when a magnetic layer used in a marker for an electronic article monitoring system of the present invention is magnetized.

FIG. 10 is a table showing pulse outputs when the magnetic layer used in the marker for the electronic article monitoring system of the present invention is demagnetized.

FIG. 11 is a table showing pulse output when a magnetic layer used in a marker for an electronic article monitoring system of the present invention is magnetized.

[Explanation of symbols]

1 Magnetic layer 1'Magnetic layer 3 Adhesive layer 4 Adhesive layer 5 Release paper 6 Metal that holds the magnetic field value of large Barkhausen discontinuity in the magnetic hysteresis loop 8 Non-magnetic casing B Non-magnetic support B'Non-magnetic support body

Claims (4)

[Claims] 1. A magnetic layer having a magnetic flux having a saturation magnetic flux density of 70 emu / g or more dispersed in a binder on one surface of a non-magnetic support, and another surface responsive to incident magnetic energy. A marker for an electronic article monitoring system, comprising a metal having a generated magnetic field value of large Barkhausen discontinuity in a magnetic hysteresis loop as a component for generating an output signal. 2. The residual magnetic flux density of the magnetic layer is in the range of 1 to 25 Mx / cm per unit width.
A marker for the electronic article monitoring system described. 3. A metal-adhesive layer having a magnetic layer on one surface of a non-magnetic support and having a magnetic field value of large Barkhausen discontinuity in a magnetic hysteresis loop on the other surface of the support. , And a release paper are laminated, and the metal is fixed on the support by an adhesive layer. 4. A metal having a magnetic layer on one surface of a non-magnetic support and having a magnetic field value of a large Barkhausen discontinuity in a magnetic hysteresis loop is provided on the other surface of the support. The marker for an electronic article monitoring system according to claim 1 or 2, wherein the marker is provided in a non-magnetic housing.