JP6990964B2 - Manufacturing method of magnetic marker, laminate and holder - Google Patents

Description

The present invention relates to a magnetic marker laid on a road.

Conventionally, a magnetic marker detection system for a vehicle that detects a magnetic marker laid on a road by a magnetic sensor attached to the vehicle is known (see, for example, Patent Document 1). According to such a magnetic marker detection system, there is a possibility that automatic driving can be realized in addition to various driving support such as automatic steering control using magnetic markers laid along the lane and lane departure warning.

Japanese Unexamined Patent Publication No. 2005-202478

However, the conventional magnetic marker has the following problems. For example, in order to realize driving support for lane departure warning, it is necessary to lay magnetic markers at relatively short intervals, and if the laying section is long, the number of magnetic markers will be enormous, so the procurement cost of magnetic markers will be high. There is a risk that it will not be possible to avoid an increase in construction costs.

The present invention has been made in view of the above-mentioned conventional problems, and provides a method for producing a magnetic marker that can efficiently produce a magnetic marker and realize cost reduction.

One aspect of the present invention is a vehicle that is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, and supports the driver's driving operation of the vehicle or realizes automatic driving that does not depend on the driver's operation. It is a method of manufacturing a magnetic marker to realize side control.
A process of producing an intermediate sheet, which is a sheet-shaped intermediate processed product, having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, and a process of producing an intermediate sheet.
A process of cutting out a magnetic marker whose outer peripheral side surface is formed by a cut surface over the entire circumference from the inside of the intermediate sheet.
A step of magnetizing each magnetic marker by applying a magnetic field along the stacking direction of the laminated body to a laminated body in which a plurality of the magnetic markers cut out by the cutting step are laminated in a state of mutual contact. Carry out,
A method for producing a magnetic marker is to obtain a laminated body in which a plurality of magnetized magnetic markers are laminated in a state of being in contact with each other by the magnetizing step, and the magnetic markers can be removed .

One aspect of the present invention is a vehicle that is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, and supports the driver's driving operation of the vehicle or realizes automatic driving that does not depend on the driver's operation. It is a laminated body in which a plurality of magnetic markers for realizing side control are laminated.
A plurality of magnetic markers cut out from an intermediate sheet, which is a sheet-shaped intermediate processed product having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, are laminated.
It is in a laminated body for removing a magnetic marker located at an end of a plurality of laminated magnetic markers and laying them on a road surface.

One aspect of the present invention is a vehicle that is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, and supports the driver's driving operation of the vehicle or realizes automatic driving that does not depend on the driver's operation. A holder that holds a laminated body in which a plurality of magnetic markers for realizing side control are laminated.
A laminated body in which a plurality of magnetic markers cut out from an intermediate sheet, which is a sheet-shaped intermediate processed product having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, is laminated can be accommodated inside a columnar structure.
The holder is configured so that the magnetic markers located at the ends of the laminated body can be transferred to the road surface one by one by pressing the take-out port forming the columnar end portion against the road surface.

The method for producing a magnetic marker of the present invention is a method for producing the magnetic marker by cutting out the intermediate sheet prepared in advance. If this manufacturing method is used, the magnetic marker can be produced efficiently, and the magnetic marker produced by this manufacturing method can reduce the product cost.

Explanatory drawing which shows the state of magnetic marker detection by a vehicle. An explanatory diagram illustrating an example of a lane in which a magnetic marker is laid. Top view and side view of the magnetic marker. A graph showing the vertical magnetic field distribution of a magnetic marker. Explanatory drawing which shows a part of the process of manufacturing a magnetic marker. Explanatory drawing of the process of punching out a magnetic marker before magnetization. Explanatory drawing of the magnetizing process for magnetizing a magnetic marker. A cross-sectional view showing a cross-sectional structure of a magnetic marker in a laid state. Explanatory drawing of a holder for transferring a magnetic marker to a road surface.

A preferred embodiment of the present invention will be described.
It is preferable to include a step of applying a magnetic field to the laminated body in which a plurality of the magnetic markers cut out by the cutting step are laminated to magnetize each magnetic marker .
In this case, the production efficiency can be further improved by magnetizing a plurality of the magnetic markers at once.

It is preferable that the cutting step is a step of punching, and is a step of using a punching die capable of sequentially accommodating the magnetic markers in the mold to form the laminated body .
If the punching die is used, the laminated body can be efficiently formed by repeating punching a plurality of times.

It is preferable that the intermediate sheet can cut out a plurality of magnetic markers of at least two pieces or more .
If a plurality of the magnetic markers can be cut out from the intermediate sheet, the production efficiency of the magnetic markers can be further increased, and the cost of the magnetic markers can be further reduced.

The magnetic powder is preferably iron oxide powder, which is a magnetic material .
For example, rare earth magnets such as neodymium magnets tend to deteriorate in performance due to oxidation, so it is necessary to store them in a highly airtight container or the like. On the other hand, in the case of iron oxide, since iron is already in an oxidized state, further oxidation is unlikely to occur. If iron oxide is used as the magnetic material of the magnetic powder, there is a high possibility that the initial performance can be maintained over a long period of use even in a laying situation where waterproof and moisture proof is insufficient. In particular, even if the cut surface at the time of cutting is exposed on the outer peripheral side surface or laid with a simple coating made of a resin material or the like, there is little risk of performance deterioration.

On the other hand, when the iron oxide powder is adopted as the magnetic powder, the magnetism generated by the magnetic marker tends to be weaker than that when, for example, a neodymium magnet or the like is adopted. Therefore, for example, it is advisable to combine a highly sensitive magnetic sensor such as a magnet impedance sensor (MI sensor), a fluxgate sensor, or a TMR type sensor. It is also good to increase the diameter of the magnetic marker. For example, if the diameter is set to 80 mm or more, the straightness of the magnetic flux generated by the magnetic marker becomes stronger, so that the damping factor in the vertical direction of the magnetic pole surface becomes lower and the magnetic strength acting on the magnetic sensor side is secured. It will be easier.

(Example 1)
This example is an example relating to a method of manufacturing a magnetic marker 1 laid on a road. This content will be described with reference to FIGS. 1 to 9.
The magnetic marker 1 of FIGS. 1 and 2 is laid, for example, along the center of the lane 530 in which the vehicle 5 travels. The magnetism of the magnetic marker 1 laid on the road surface 53 in this way can be detected by, for example, a magnetic sensor 2 attached to the bottom surface 50 of the vehicle 5. The detection signal of the magnetic sensor 2 is input to, for example, an ECU (not shown) on the vehicle 5 side, and various controls such as automatic steering control for maintaining the lane, driving support control such as lane departure warning, and control for automatic driving. Used for.

As shown in FIG. 3, the magnetic marker 1 is a flat circular sheet-shaped marker having a diameter of 100 mm and a thickness of 1.5 mm. The magnetic marker 1 has a three-layer structure in which a protective layer 12 made of a resin material is laminated on both the front and back surfaces of a magnetic layer 11 that generates magnetism. The magnetic layer 11 is a layer of an isotropic ferrite rubber magnet in which magnetic powder, which is iron oxide powder, is dispersed in rubber, which is a base material. In this example, an isotropic ferrite rubber magnet having a maximum energy product (BHmax) = 6.4 kJ / m ³ is adopted.

Here, Table 1 shows a part of the specifications of the magnetic marker 1 to be manufactured.

When computer simulation by axially symmetric three-dimensional static magnetic field analysis using the finite element method is used, the magnetic field distribution in the vertical direction on which the magnetic marker 1 having a surface magnetic flux density Gs of 1 mT and a diameter of 100 mm acts can be obtained as shown in FIG. In the figure, the logarithmic scale of the magnetic flux density acting in the vertical direction is set on the vertical axis, and the height in the vertical direction (height from the marker surface) with respect to the surface of the magnetic marker 1 is set on the horizontal axis. It is a semi-logarithmic graph. According to the figure, the magnetic flux density on which the magnetic marker 1 acts is 8 microtesla (0.08 × 10 ^-4 tesla) at a position of 250 mm assumed as the mounting height of the magnetic sensor 2 on the vehicle 5 side. I can understand that. The accuracy of the computer simulation used has been confirmed in advance by the inventors through empirical experiments.

For example, if a high-sensitivity Magneto Impedance (MI) sensor with a magnetic flux density measurement range of ± 0.6 millitesla and a magnetic flux resolution of 0.02 microtesla within the measurement range is used, the magnetic marker 1 The magnetic field of 8 microtesla on which is acting can be detected with high certainty. Here, the MI sensor is a magnetic sensor using a magnetoimpedance element including a magnetic sensor whose impedance changes according to an external magnetic field. In the magnetic impedance element (MI element), the depth (thickness) of the skin layer fluctuates due to the external magnetic field due to the skin effect in which the current density of the skin layer increases when a pulse current or high-frequency current flows through the magnetic sensor. This is an element that detects magnetism by utilizing the magnetic impedance effect (MI effect) in which the impedance of the magnetic sensor changes sensitively. According to the MI element that utilizes such an MI effect, highly sensitive magnetic measurement is possible. A large number of applications have been filed for MI sensors using MI elements, and detailed descriptions are given in, for example, WO2005 / 19851, WO2009 / 119081 and Patent 4655247.

Next, a method for manufacturing the magnetic marker 1 having the above configuration will be described with reference to FIGS. 5 to 7. In this manufacturing method, after the magnetic sheet 104A forming the magnetic layer 11 is manufactured, an intermediate sheet 104B for punching (cutting out) in which layers forming the protective layer 12 are laminated on both the front and back surfaces thereof is obtained as an intermediate processed product. This is a method of punching (cutting out) the magnetic marker 1 before magnetization from the intermediate sheet 104B to magnetize it.

In producing the magnetic sheet 104A, first, a slurry 113 in which magnetic powder 111 (iron oxide powder in this example) is kneaded into a fluid rubber as a base material is produced (FIG. 5A). After the pellet 101 (FIG. 5 (b)) obtained by molding the slurry 113 into a predetermined shape is dried, it is thinly rolled into a sheet shape by a rolling roller 102. As a result, a sheet-shaped magnetic sheet 104A can be produced (FIG. 5 (c)).

The intermediate sheet 104B in FIG. 5D is a sheet body in which a protective layer 12 made of a resin material is laminated on both the front and back surfaces of the magnetic sheet 104A. The protective layer 12 can be formed by applying, for example, a plastic resin mixed with a curing agent to the surface of the magnetic sheet 104A. The cross-sectional structure of the intermediate sheet 104B is a three-layer structure (not shown) in which the second layer forming the protective layer 12 is laminated on both the front and back surfaces of the first layer forming the magnetic layer 11.

The intermediate sheet 104B is a large-sized sheet capable of punching a plurality of magnetic markers 1 as shown by a broken line circle indicating a planned punching position (FIG. 5 (d)). When punching out the magnetic marker 1, as shown in FIG. 6, a cylindrical punching die 3 capable of accommodating the punched out magnetic marker 1 is used. The punching die 3 is inserted into a Thomson holder 32 that is driven up and down by a hydraulic cylinder (not shown), a substantially cylindrical Thomson type 31 having a circular cutting edge at the tip, and a Thomson type 31. It is configured to include a suction unit 33 slidable in the cylinder direction.

The suction unit 33 of FIG. 6 includes a suction port 330 for connecting a tube extending from an air pump (not shown), and the suction port 330 communicates with a suction port 332 on the front end surface via a pneumatic circuit. As shown in the figure, the suction unit 33 sucks the magnetic marker 1 punched out from the intermediate sheet 104B and retracts by the thickness of each new magnetic marker 1 punched out in the Thomson mold 31. The magnetic markers 1 are sequentially laminated.

If the punching die 3 having such a configuration is used and the punching process is continuously performed while sequentially shifting the positions of the intermediate sheets 104B, the laminated body 100 in which a plurality of magnetic markers 1 are superposed can be formed. It is also possible to replace the intermediate sheet 104B during the continuous punching process. If the intermediate sheet 104B is replaced in the middle, a laminated body 100 in which a larger number of magnetic markers 1 are laminated can be obtained.

After punching a predetermined number of times, the laminated body 100 is taken out from the punching die 3, and the magnetic marker 1 constituting the laminated body 100 is collectively magnetized. This step illustrated in FIG. 7 is carried out using a magnetizing device including a cylindrical coil 35 around which the electric wire 350 is wound.

The coil 35 is formed so that the laminated body 100 can be interpolated and arranged. If electric power is supplied to the coil 35 with the laminated body 100 interpolated, the magnetic field generated from the coil 35 can act on the laminated body 100. By applying a magnetic field to the laminated body 100 in this way, the magnetic powder constituting the magnetic layer 11 of each magnetic marker 1 constituting the laminated body 100 can be magnetized, whereby the magnetic marker 1 can be magnetized. In particular, if a cylindrical coil 35 that is longer than the laminated body 100 in a cylindrical method is used as described above, a magnetic field can be applied to each magnetic marker 1 constituting the laminated body 100 with high uniformity, and the magnetic characteristics can be changed. A high-quality magnetic marker 1 with little variation can be manufactured.

When laying the magnetic marker 1, the magnetic marker 1 removed from the magnetized laminate 100 is placed on the road surface 53 to which an adhesive is applied in advance. Then, after the bonding is completed by curing the adhesive, a powder coating material obtained by mixing an aggregate such as sand in a polyamide resin material is applied to the surface of the magnetic marker 1.

When such a construction procedure is executed, as shown in FIG. 8, the bonding layer 16 is formed in the gap between the magnetic marker 1 and the road surface 53, and the anti-slip layer 15 in which the aggregate is mixed in the polyamide resin material is surfaced. The laid state formed on the side can be realized. Here, the thickness of the magnetic marker 1 is 1.5 mm, which is thinner than the white line printed on the road surface 53 and the road markings such as the speed limit display, so that there is little possibility of hindering the vehicle traveling. Further, since the anti-slip layer 15 mixed with the aggregate is laminated on the surface side, the possibility of slipping of the vehicle tire is reduced. Note that FIG. 8 illustrates the cross-sectional structure of the outer peripheral portion of the magnetic marker 1. As illustrated in the figure, the outer peripheral side surface of the magnetic marker 1 is formed by a cut surface by punching, but a polyamide resin material mixed with an aggregate may be applied so as to cover the cut surface.

According to the above method for producing a magnetic marker, the magnetic marker 1 can be efficiently produced by punching. In particular, since the intermediate sheet 104B is a large-sized sheet capable of punching out a plurality of magnetic markers 1, the production efficiency of the magnetic markers 1 can be improved by continuously punching the intermediate sheets 104 while shifting the punching points. Further, in the case of the punched die 3 illustrated, the punched magnetic marker 1 can be taken into the die to form the laminated body 100. When a plurality of magnetic markers 1 are laminated as the laminated body 100, the plurality of magnetic markers 1 can be handled collectively, which is highly convenient.

For example, it is also possible to transport the magnetized laminated body 100 to the construction site as it is, and perform the laying work while removing the magnetic marker 1 from the laminated body 100 in the field work. Further, for example, as shown in FIG. 9, a work vehicle equipped with a holder 34 that accommodates the laminated body 100 and supplies the magnetic marker 1 one by one from the take-out port 340 is adopted, and the magnetic marker 1 is pushed one by one so as to push the stamp. It is also good to lay it so that it is attached to the road surface 53.

The holder 34 has, for example, a support plate 341 urged in the extrusion direction by the urging member 342. The laminate 100 urged in the extrusion direction by the support plate 341 is positioned so that the end faces are flush with each other with respect to the take-out port 340 whose inner diameter is slightly narrowed. If the holder 34 is pressed against the road surface 53 so as to push the stamp in this state, one magnetic marker 1 located on the end surface of the laminated body 100 can be transferred to the road surface 53. Then, the laminated body 100 urged by the support plate 341 is extruded until it is flush with the take-out port 340, advances by the thickness of one sheet, and the next magnetic marker 1 can be transferred to the road surface 53. Become.

Iron oxide is used as the magnetic powder forming the magnetic layer 11 of the magnetic marker 1, and this iron oxide is suitable for producing the magnetic marker 1 by punching. This is because iron oxide is less likely to deteriorate in performance due to oxidation, so that treatment such as coating of the punched cross section appearing on the outer peripheral side surface of the magnetic marker 1 is unnecessary, or simple treatment can be applied.

Further, in the manufacturing method of this example, each magnetic marker 1 constituting the laminated body 100 is efficiently magnetized by applying a magnetic field to the laminated body 100 in which a plurality of magnetic marker 1s are laminated. If the magnetic marker 1 can be magnetized efficiently in this way, the production efficiency of the magnetic marker 1 can be increased, the production cost can be suppressed, and the low cost can be realized. Further, if the low-cost magnetic marker 1 is adopted, it is possible to suppress an increase in the construction cost even in the construction in which the number of magnetic markers 1 laid is very large because the laying section is long or the number of lanes is large.

In this example, the procedure of punching out the magnetic marker 1 and laminating in the punching die 3 to generate the laminated body 100 has been described. It is also good to stack them one by one. Further, the magnetic marker 1 may be manufactured without punching.

Although the MI sensor is exemplified as the magnetic sensor that detects the magnetic marker 1, a high-sensitivity sensor that adopts another principle such as a fluxgate sensor or a TMR type sensor may be combined instead. The fluxgate sensor is a highly sensitive magnetic sensor that measures the magnetic strength from the saturation timing by utilizing the fact that the saturation timing of the core magnetic flux when a periodic current is passed through the soft magnetic core changes according to the external magnetic field. .. A large number of applications have been filed for fluxgate sensors, and detailed descriptions are given in, for example, WO2011 / 155527 and Japanese Patent Application Laid-Open No. 2012-154786.
The TMR (Tunneling Magneto Resistive) type sensor has a structure in which an insulator layer with a thickness of about 1 nm is sandwiched between the ferromagnetic layers, and when a voltage is applied perpendicular to the film surface, a current is applied to the insulator layer due to the tunnel effect. It is a highly sensitive magnetic sensor that utilizes the tunnel magnetoresistive (TMR) effect, in which the electric resistance at that time changes greatly according to the external magnetic field. A large number of applications have been filed for TMR type sensors, and detailed descriptions are given in, for example, WO2009 / 078296A and JP2013-242299A.

In this example, rubber, which is a polymer material, is exemplified as a base material forming the magnetic layer 11 constituting the magnetic marker 1. Instead of this, a resin material such as asphalt or plastic, which is a polymer material, may be adopted as a base material. If rubber is used as the base material, it becomes a rubber magnet, and if plastic is used as the base material, it becomes a plastic magnet. Many magnets in which magnetic powder is dispersed using a polymer material such as asphalt, rubber, or resin material as a base material have flexibility and have an advantage that cracking is less likely to occur as compared with magnets such as sintered magnets. If the magnetic marker 1 has high flexibility, it can cope with the unevenness of the road surface 53 at the time of construction, so that construction defects can be suppressed. In addition, since it is possible to cope with deformation of the road surface during operation, it is possible to suppress the occurrence of defects during a long period of use. Further, since the magnetic sheet using a polymer material such as asphalt as a base material can be molded with high accuracy at a relatively low cost, it is possible to provide a high quality magnetic marker 1 while suppressing the production cost.

The magnetic material forming the magnetic powder 111 is not limited to the iron oxide of this example, and various materials such as neodymium and samarium cobalt can be adopted. As for the material forming the base material and the magnetic material forming the magnetic powder 111, it is preferable to selectively determine an appropriate magnetic material according to the magnetic specifications, environmental specifications, etc. required for the magnetic marker 1. Iron oxide in a state where the metal is already oxidized has an advantage that the performance deterioration due to rust and the like is small and the initial performance can be maintained for a long period of time.

In this example, the magnetic markers continuously arranged along the lane are illustrated, but for example, they are arranged in front of the branch road or the like in order to notify the approach information to the branch road or the intersection. It may be a magnetic marker.
Although the construction of forming the anti-slip layer 15 after joining the magnetic marker 1 to the road surface 53 has been exemplified, instead of this, a layer to be the anti-slip layer 15 may be laminated in advance on the intermediate sheet 104B.

Although the specific examples of the present invention have been described in detail as in the examples, these specific examples merely disclose an example of the technology included in the claims. Needless to say, the scope of claims should not be construed in a limited manner by the composition and numerical values of specific examples. The scope of claims includes technologies that are variously modified, modified, or appropriately combined with the above-mentioned specific examples by utilizing known technologies, knowledge of those skilled in the art, and the like.

1 Magnetic marker 100 Laminated body 104A Magnetic sheet 104B Intermediate sheet 11 Magnetic layer 12 Protective layer 15 Anti-slip layer 16 Joint layer 2 Magnetic sensor 3 Punch type 35 Coil 350 Electric wire 5 Vehicle 53 Road surface

Claims (12)

It is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, to support the driving operation of the vehicle by the driver, or to realize the control on the vehicle side to realize automatic driving that does not depend on the driver's operation. It is a method of manufacturing a magnetic marker of
A process of producing an intermediate sheet, which is a sheet-shaped intermediate processed product, having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, and a process of producing an intermediate sheet.
A process of cutting out a magnetic marker whose outer peripheral side surface is formed by a cut surface over the entire circumference from the inside of the intermediate sheet.
A step of magnetizing each magnetic marker by applying a magnetic field along the stacking direction of the laminated body to a laminated body in which a plurality of the magnetic markers cut out by the cutting step are laminated in a state of mutual contact. Carry out,
A method for producing a magnetic marker, which obtains a laminated body in which a plurality of magnetized magnetic markers are laminated in a state of being in contact with each other by the magnetizing step, and the magnetic markers can be removed . In claim 1, the method for producing a magnetic marker, wherein the intermediate sheet is a sheet having a structure in which a layer made of a resin material is laminated on a layer in which the magnetic powder is dispersed in a base material. In claim 1 or 2 , the cutting step is a step of punching, and is a step of sequentially accommodating the magnetic markers in a mold and using a punching die capable of forming the laminate. Method. In any one of claims 1 to 3, the laminated body can be accommodated inside the columnar body, and is located at the end portion of the laminated body by pressing the take-out port forming the end portion of the columnar body against the road surface. A method for producing a magnetic marker in which the laminated body is housed in a holder configured so that the magnetic markers can be transferred one by one to the road surface. The method for producing a magnetic marker according to any one of claims 1 to 4 , wherein the intermediate sheet can cut out a plurality of magnetic markers of at least two pieces or more. The method for producing a magnetic marker, wherein the magnetic powder is a powder of iron oxide, which is a magnetic material, according to any one of claims 1 to 5 . It is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, to support the driving operation of the vehicle by the driver, or to realize the control on the vehicle side to realize automatic driving that does not depend on the driver's operation. It is a laminated body in which a plurality of magnetic markers of
A plurality of magnetic markers cut out from an intermediate sheet, which is a sheet-shaped intermediate processed product having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, are laminated.
A laminated body for removing the magnetic marker located at the end of a plurality of laminated magnetic markers and laying them on the road surface. In claim 7 , the intermediate sheet is a sheet having a structure in which a layer made of a resin material is laminated on a layer in which the magnetic powder is dispersed in a base material.
Each magnetic marker laminated in the laminate has a multilayer structure in which a layer made of a resin material is laminated with respect to a layer in which the magnetic powder remains in the base material. In claim 7 or 8 , the laminated body can be accommodated inside the columnar body, and the magnetic marker located at the end portion of the laminated body is pressed one by one by pressing the take-out port forming the end of the columnar body against the road surface. A laminate housed in a holder, which is configured to be transferable to the road surface. It is laid on the road surface so that it can be detected by a magnetic sensor attached to the vehicle, to support the driving operation of the vehicle by the driver, or to realize the control on the vehicle side to realize automatic driving that does not depend on the driver's operation. A holder that holds a laminated body in which a plurality of magnetic markers are stacked.
A laminated body in which a plurality of magnetic markers cut out from an intermediate sheet, which is a sheet-shaped intermediate processed product having a layer in which magnetic powder, which is a powder of a magnetic material, is dispersed in a base material, is laminated can be accommodated inside a columnar structure.
A holder configured so that magnetic markers located at the ends of the laminated body can be transferred to the road surface one by one by pressing the take-out port forming the columnar end to the road surface. The holder according to claim 10 , further comprising a support plate for extruding the laminate so that the end faces of the laminate substantially coincide with the opening surface of the take-out port. In claim 10 or 11 , the intermediate sheet is a sheet having a structure in which a layer made of a resin material is laminated on a layer in which the magnetic powder is dispersed in a base material.
A holder that holds a laminated body in which a plurality of magnetic markers having a multilayer structure in which a layer made of a resin material is laminated on a layer in which the magnetic powder is dispersed in a base material are laminated.

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