Magnetic identification sensor

Abstract

[Problem] To make it possible to adjust the magnetic field strength applied to a magnetic detection body regardless of the magnetization direction of a magnet. [Solution] A magnetic identification sensor 200 that moves a medium 100 that includes a magnetic body 110 along a transport surface 211 and detects a magnetic pattern for the magnetic body 110 is characterized by comprising a magnetic detection unit 300 at which a first magnet 520a and a magnetic detection element 410 are arranged in the given order along the movement direction of the medium 100 relative to the transport surface 211, the magnetic detection element 410 being fixed to a first holding member 420, and the first magnet 520a being fixed to a second holding member 530 that has a guide surface 531 that allows for movement relative to the first holding member 420 such that the directions in which movement are possible are restricted.

Description

Magnetic Identification Sensor

[0001] The present invention relates to a magnetic identification sensor that uses a magnetic detection element with a magnet disposed nearby to identify the type and authenticity of a medium such as a magnetic ink print containing a magnetic substance.

[0002] For magnetic identification sensors consisting of a magnet and a magnetic detection element, it is desirable to use a magnet with a strong magnetic force and a highly sensitive magnetic detection element to improve detection accuracy. High-sensitivity magnetic detection elements become magnetically saturated when a strong magnetic field is applied and no longer function as magnetic detection elements. Therefore, it is necessary to precisely determine the relative position of the magnetic detection element and the magnetic field so that the magnetic field applied to the magnetic detection element of the magnetic detection element has the required strength in the magnetic detection direction. The magnetization direction of a magnet depends on the orientation of the magnet's crystal grains, and because this orientation is not uniform, it is difficult to determine the positional relationship between the magnetic field and the magnetic detection element using only predetermined machine dimensions, and position adjustment work is required to match the orientation of the magnet being used. Patent Document 1 proposes a structure that facilitates position adjustment work for a magnetic identification sensor in which a magnetic detection element is placed between two magnets.

[0003] JP 2019-184382 A

[0004] In a magnetic identification sensor in which a magnetic detection element is placed between multiple magnets, the magnetic field applied to the magnetic detection body of the magnetic detection element is a composite magnetic field of the magnetic fields generated by each magnet. Because the magnetization direction of each magnet is not uniform, the composite magnetic field is not determined until the positions of all magnets placed around the magnetic detection body are determined. Only once the positions of all magnets are determined can the composite magnetic field be determined, which means that the point or range where the required magnetic field strength is achieved in the magnetic detection direction of the magnetic detection body is determined. In a magnetic identification sensor, the magnetic detection body must be placed at a point or range where the required magnetic field strength is achieved.

[0005] In the magnetic identification sensor proposed in Patent Document 1, a first magnet is positioned relative to a magnetic detection element, and a second magnet is positioned approximately symmetrically to the first magnet around the magnetic detection element. The second magnet's position is determined by linear or rotational adjustment, or both, while checking the magnetic field strength applied to the magnetic detection body. The appropriate adjustment position and angle of the second magnet are affected by the relative position and angle between the first magnet and the magnetic detection body and the magnetization directions of the first and second magnets. Because the relative position and angle between the first magnet and the magnetic detection body are determined first, the second magnet has three degrees of freedom: position, angle, and magnetization direction. The adjustment range for the position and angle is limited by the structure around the magnet and the specifications required for the magnetic identification sensor. Therefore, if the required magnetic field strength is not achieved in the magnetic detection direction by adjusting the magnet position and angle within the limited range, the magnetization direction of the second magnet must be adjusted. Since the magnetization direction is determined by the individual magnet, the magnet itself must be changed, and if the required magnetic field strength cannot be obtained with any magnet, the required performance as a magnetic identification sensor cannot be obtained.

[0006] In view of the above, the magnetic identification sensor of the present invention is a magnetic identification sensor that moves a medium containing a magnetic material relatively along a transport surface and detects the magnetic pattern of the magnetic material, and is characterized in that it includes a magnetic detection unit in which a first magnet, a magnetic detection element, and a second magnet are arranged in that order along the transport surface, the magnetic detection element being fixed to a first holding member, and the first and second magnets being fixed to a second holding member that is movable relatively to the first holding member.

[0007] According to the present invention, by first determining the position of the magnet and identifying the point or range of magnetic field strength required, it becomes possible to adjust the magnetic field strength applied to the magnetic detector regardless of the magnetization direction of the magnet. Furthermore, by limiting the movable direction of the magnet and magnetic detection element using each holding member, adjustment can be easily performed.

[0008] Overall view of the magnetic identification sensor Explanatory diagram of a composite magnetic field formed by two magnets Enlarged view of element holding member 420 Enlarged view of magnet holding member 530 Explanatory diagram of position adjustment of magnet unit 500 using a guide surface Explanatory diagram of position adjustment of magnet unit 500 to place magnetic detection body 411 within magnetic field range S Perspective view of another embodiment of the magnetic identification sensor Explanatory diagram of another embodiment of the magnetic identification sensor Conceptual diagram of the peripheral structure when the magnetic identification sensor is incorporated into a magnetic identification device accompanied by a conveying system 600 Explanatory diagram of a rib provided on the sliding section Explanatory diagram of another rib provided on the sliding section

[0009] The magnetic identification sensor according to the present invention will be described in detail below with reference to the illustrated embodiments. Note that the same elements are designated by the same reference numerals throughout this specification and the accompanying drawings, and redundant explanations will be omitted.

[0010] 1A and 1B are overall views of a magnetic identification sensor according to this embodiment. Fig. 1A is an overall perspective view showing an example of the configuration of a magnetic identification sensor 200 according to this embodiment. For the purpose of explanation, a portion is shown transparently to show the internal structure. Fig. 1B is an exploded perspective view illustrating the configuration of the magnetic identification sensor 200.

[0011] The magnetic medium 100 is a paper-like medium that includes a magnetic material 110. An example is a banknote printed with magnetic ink that includes a magnetic material. The magnetic material 110 includes a hard magnetic material and a soft magnetic material.

[0012] The magnetic identification sensor 200 includes a magnetic detection unit 300 composed of a magnetic detection element 410 and two magnets 520a and 520b to detect the magnetic field of the magnetic medium 100 transported by a transport means (not shown) on the sliding surface 211 of the sliding part 210. In this embodiment, the magnet 520a, magnetic detection element 410, and magnet 520b are arranged in this order along the moving direction Ly of the magnetic medium 100. The magnetic medium 100 is moved relative to the magnetic detection element 410, and the magnetic field generated by the magnets 520a and 520b during the relative movement causes the magnetic field or a change in magnetic field (magnitude of magnetic field) generated in the magnetic body 110 to be detected by the magnetic detection element 410. If the magnetic body 110 is a soft magnetic body, the amount of magnetic field generated is extremely small when there is no magnetic field. Therefore, the magnetic field generated by the magnetic body 110 is detected while a magnetic field is applied by the magnets 520a and 520b. In this way, the magnetic identification sensor 200 detects the amount of magnetic field generated by the magnetic material 110 of the magnetic medium 100 , and detects the magnetic pattern of the magnetic medium 100 .

[0013] In the following description, when there is no need to distinguish between the two magnets 520a and 520b, they will be simply referred to as magnets 520. The magnets 520a and 520b will also be referred to as the first magnet and the second magnet, respectively. The magnetic detection element 410 includes a plurality of magnetic detection bodies 411 arranged side by side in the XZ plane shown in FIG.

[0014] The magnetic detection unit 300 is composed of a magnetic detection element 410 fixed to an element holding member 420, and magnets 520a and 520b fixed to a magnet holding member 530. The magnet holding member 530 is arranged inside the element holding member 420 to avoid the magnetic detection element 410, and is arranged below the sliding surface 211 (also referred to as the conveying surface) of the sliding part 210, with the magnet 520a, magnetic detection element 410, and magnet 520b lined up in this order along the medium conveying direction Ly (i.e., the Y direction) indicated by the arrow. A composite magnetic field consisting of the magnetic fields emitted from the magnets 520a and 520b is applied to the magnetic detection body 411. The composite magnetic field will be described later.

[0015] The element unit 400 is composed of a magnetic detection element 410 and an element holding member 420, and the magnetic detection element 410 is fixed to the element holding member 420. The element holding member 420 has a guide surface 421 that comes into contact with the magnet holding member 530 to limit the direction in which the magnet holding member 530 can move relative to the element holding member 420 (i.e., the direction in which the magnet 520 can move relative to the magnetic detection element 410). The guide surface will be described later.

[0016] The magnet unit 500 is composed of two magnets 520a, 520b and a magnet holding member 530. As shown in FIG. 1A, the two magnets 520a, 520b are fixed to the magnet holding member 530 as a pair of magnets, parallel to each other with a predetermined distance D between them and aligned along the medium transport direction Ly. The pair of magnets 520a, 520b are arranged with opposite polarities. Therefore, the magnetic pole of one magnet 520a on the side closest to the sliding surface 211 is a north pole, and the magnetic pole of the other magnet 520b on the side closest to the sliding surface 211 is a south pole. Fixing the magnets 520 to the magnet holding member 530 determines the relative positions of the magnets 520 and the distribution of the composite magnetic field generated between the two magnets 520. The magnet holding member 530 has a guide surface 531, shown in FIG. 1A, at a portion facing the guide surface 421 of the element holding member 420. The guide surface 531 comes into contact with the element holding member 420 to restrict the direction in which the element holding member 420 can move relative to the magnet holding member 530 (i.e., the direction in which the magnetic detection element 410 can move relative to the magnet 520). The guide surface 531 will be described later.

[0017] The magnet 520 has a rectangular parallelepiped structure and is cut out from a block of material. It is generally preferable to use parts of the same shape to achieve a symmetrical magnetic field distribution. However, the two magnets 520a and 520b are not limited to the same shape; they may have different shapes. The magnet 520 may also be positioned on only one side of the magnetic detection element 410 in the Y direction. Because a magnetic field of at least several hundred gauss is required on the sliding surface 211, Nd-Fe-B or Sm-Co rare earth magnets are suitable as materials for the magnet 520. To orient the north-south direction of the magnet 520 perpendicular to the sliding surface 211 (i.e., the Z direction), the material is cut so that the north-south direction is perpendicular to the surface of the rectangular parallelepiped magnet that is closest to the lower part of the sliding surface 211.

[0018] The sliding portion 210 is made of a flat plate of a non-magnetic material, i.e., a plate-shaped member. To avoid wear caused by the passage of the magnetic medium 100, the sliding portion 210 may be made of a non-magnetic metal plate such as a copper-based metal plate. Furthermore, to reduce spacing loss between the magnetic medium 100 and the magnetic detection element 410, a thin plate is preferable for the sliding portion 210. As shown in FIG. 1B , ribs (reinforcements) 212 are provided on the sides of the sliding portion 210. This prevents deformation of the sliding surface 211 and stabilizes the accuracy of magnetic detection by the magnetic detection element 410.

[0019] FIG. 2 is an explanatory diagram for explaining a composite magnetic field formed by two magnets 520. As shown in FIG.

[0020] Figures 2(A) and (B) show the magnetization direction of a single magnet. For the ideal magnet shown in Figure 2(A), the magnetization direction can be easily determined from the magnet's shape. However, for actual magnets, as shown in Figure 2(B), a magnetization direction gradient θ1 occurs relative to the magnet's shape. Because the magnetization direction gradient θ1 is determined by the orientation of the crystal grains that make up the magnet, it is impossible to mechanically determine the magnetization direction gradient θ1 from the magnet's shape. Figures 2(C) and (D) show the composite magnetic field formed by two magnets. The ideal composite magnetic field formed by two magnets shown in Figure 2(C) is distributed symmetrically about the midpoint between the two magnets, making it possible to identify the point or range S (hereinafter referred to as the magnetic field range S) where the required magnetic field strength is achieved relative to the magnetic detection direction of the magnetic detector. However, because actual magnets have a magnetization direction gradient θ1 as shown in Figure 2(D), it is extremely difficult to determine the position of the magnetic field range S from the magnet's shape, as with the actual magnetization direction.

[0021] 3A and 3B are enlarged views for explaining the shape of the element holding member 420 according to this embodiment. Fig. 3A is a perspective view of the element holding member 420, Fig. 3B is a side view of the element holding member 420 as viewed from the X direction, and Fig. 3C is a side view of the element holding member 420 as viewed from the Y direction.

[0022] The element holding member 420 has an element fixing surface 425 to which the magnetic detection element 410 and components such as a circuit board associated with the magnetic detection element 410 are fixed. The element holding member 420 also has a guide surface 421 that abuts against a guide surface 531 of the magnet holding member 530. The element holding member 420 also has a guide surface 422 that abuts against or is close to a guide surface 532 of the magnet holding member 530. Although the element fixing surface 425 is shown in FIG. 3A as a plane normal to the Z direction, it may be a plane normal to the Y direction or a plane normal to the X direction, depending on the orientation of the magnetic detection body 411 of the magnetic detection element 410 and the associated circuit board, or may be composed of multiple surfaces including curved surfaces. The guide surfaces 421 and 422 abut against or are close to the guide surfaces 531 and 532 of the magnet holding member 530, respectively, thereby partially restricting the relative movement between the element unit 400 and the magnet unit 500 in a predetermined direction. The guide surface may be a cam surface depending on the direction to be restricted.

[0023] 4A and 4B are enlarged views illustrating the shape of the magnet holding member 530 according to this embodiment. Fig. 4A is a perspective view of the magnet holding member 530, Fig. 4B is a side view of the magnet holding member 530 as viewed from the X direction, and Fig. 4C is a side view of the magnet holding member 530 as viewed from the Y direction.

[0024] The magnet holding member 530 has a surface 535 that fixes the two magnets 520 facing each other. The magnet holding member 530 also has guide surfaces 532 that are positioned parallel to the direction Ly and perpendicular to the surface 535, and that face each other. The magnet holding member 530 also has a guide surface 531 at the end of the surface 532 (the bottom of the magnet holding member 530) that is formed of a curved surface that is perpendicular to the surface 532.

[0025] Furthermore, a through-hole 536 is provided in the center of the surface 535 to prevent interference with the element unit 400 when the magnet holding member 530 is placed on the element holding member 420. While the surface 535 is shown as a single plane in FIG. 4 , the magnet 520 is not limited to being of the same shape as described above and may be configured with different shapes, and therefore may be composed of multiple divided surfaces, multiple angled surfaces, or a curved surface. The guide surface 531 is preferably an arcuate surface centered on a virtual point 537 that passes through the midpoint between the fixing surface of the magnet 520 to the surface 535 and the opposing end surface. This shape is intended to minimize the amount of movement of the magnet 520 in the Z direction by adjusting the position of the magnet unit 500 while the guide surface 531 and the guide surface 421 of the element holding member 420 are in contact, as shown in FIG. 6 . Here, minimizing the movement of the magnet 520 in the Z direction means minimizing the fluctuation of the magnetic field applied to the magnetic detection body 411 by the magnets 520a and 520b in the Z direction as much as possible when adjusting the position of the magnet unit 500. In other words, when adjusting the inclination of the magnetic poles as described with reference to FIG. 2, it is preferable to adjust only the inclination of the magnetic poles as much as possible. To achieve this, it is preferable that the guide surface 531 be an arcuate surface centered on a virtual point 537. As shown in FIG. 8, if the structure of the magnetic identification sensor 200 aims to minimize the movement of other parts, the guide surface 531 may be an arcuate surface centered on a point other than the virtual point 537 (see FIG. 8A), a surface including a vertex that serves as the rotation axis when adjusting the position of the magnet holding member 530 (see FIG. 8B), or a cam-shaped curved surface that realizes complex operations (see FIG. 8C).

[0026] 5 is an explanatory diagram of the position adjustment of the magnet unit 500 using the guide surfaces. Here, the effect of the guide surfaces provided on the element holding member 420 and the magnet holding member 530 in the position adjustment of the magnet unit 500 will be described.

[0027] 5A, 5B, and 5C show how the magnet holding member 530, to which the magnet 520 is fixed, is assembled into the element holding member 420, to which the magnetic detection element 410 is fixed. At this time, the guide surface 421 of the element holding member 420 abuts against the guide surface 531 of the magnet holding member 530. The guide surface 422 of the element holding member 420 also abuts against the guide surface 532 of the magnet holding member 530. A slight clearance is provided to prevent the guide surface 531 from abutting both sides of the guide surface 422 simultaneously. This allows the magnet holding member 530 to be adjusted in the X direction while still providing a rough guide. In the following description, when there is no need to distinguish between the guide surfaces 531, 532, 421, and 422, they are simply referred to as guide surfaces. These guide surfaces serve to partially limit the relative movement between the element unit 400 and the magnet unit 500. That is, the magnet unit 500 can only move linearly in both directions in the Lx direction, linearly in both directions in the Ly direction, forward linear movement in the Lz direction, and rotational movement in the Rx direction relative to the element unit 400, as shown in FIG. 5D.

[0028] 6A and 6B are explanatory diagrams illustrating the position adjustment of the magnet unit 500 to place the magnetic detection body 411 within the magnetic field range S shown in Fig. 2D. Fig. 6A shows the state before adjustment, and Figs. 6B and 6C show the state after adjustment.

[0029] In FIG. 6A, the magnet 520 is already fixed to the magnet holding member 530, so the magnetic field range S shown in FIG. 2D is already defined. To achieve high sensitivity as a magnetic identification sensor, the position of the magnetic detection element 411 can be adjusted by moving the magnet unit 500 in the Ly and Rx directions (rotational directions with the X-axis direction as the central axis) in FIG. 6A so that the magnetic detection element 411 is positioned within the magnetic field range S. The guide surfaces shown in FIGS. 3, 4, and 5 limit movement directions and rotations that are not necessary for position adjustment. In other words, the movement direction and rotational planes during position adjustment are defined, making position adjustment easy. This contributes to the excellent mass productivity of the magnetic identification sensor. In particular, by adjusting the position of the magnet unit 500 while maintaining the abutting state between the guide surfaces 421 and 531, the rotation axis of the magnet unit 500 in the Rx direction becomes the virtual point 537, making it easy to minimize the displacement Δz in the Z direction of the upper end surface of the magnet 520 that occurs when the magnet unit 500 is rotated in the Rx direction. Furthermore, by providing such an adjustment mechanism in the element unit 400 and the magnet unit 500, it is possible to achieve a miniaturized magnetic identification sensor while facilitating adjustment.

[0030] <Other Embodiments> Figure 7 shows a perspective view of another embodiment of the magnetic identification sensor according to the present invention. In the embodiment described using Figure 1(B), ribs (reinforcing portions) 212 are provided on the sides of the sliding portion 210, but in the embodiment described in Figure 7, no ribs are provided. The present invention can be suitably applied even when no ribs are provided, taking into consideration the thickness of the sliding portion 210 and the type of magnetic medium 100 being transported.

[0031] FIG. 8 also shows an explanatory diagram illustrating another embodiment of the magnetic identification sensor according to the present invention. As described above, FIGS. 8(A) to 8(C) show other examples of guide surfaces 421 and 531. The guide surface 531 shown in FIG. 8(A) is configured as an arc surface centered at a point different from the virtual point 537 described above. The guide surface 531 shown in FIG. 8(B) is configured as a surface including a vertex that serves as the rotation axis for adjusting the position of the magnet holding member 530. The guide surface 421 shown in FIG. 8(C) is configured as a cam-shaped curved surface that enables complex operations. FIGS. 8(D) to 8(F) show other examples of guide surface 422. FIG. 8(D) shows an example in which the guide surface 422 is provided with rectangular convex portions 422a that are continuous in the Z direction and multiple rows of convex portions in the Y direction. FIG. 8(E) shows an example in which the guide surface 422 is provided with semicircular convex portions 422b that are continuous in the Z direction and multiple rows of convex portions in the Y direction. 8(F) shows an example in which a semicircular convex portion 422c is provided on the guide surface 422 in the Y direction and is provided on a part of the guide surface 422 in the Z direction. Note that this is just an example, and other configurations are also possible.

[0032] Next, an embodiment of the rib (reinforcing portion) 212 provided on the sliding portion 210 of the magnetic identification sensor 200 will be further described.

[0033] To reduce noise and increase sensitivity in the output obtained from magnetic identification sensor 200, it is necessary to make the distance between the magnetic detection body of the magnetic detection element and the magnetic medium to be detected as short as possible and to strengthen the magnetic field applied to the magnetic detection body. For this reason, it is desirable to use a thin member made of a non-magnetic material such as a copper-based material or resin for the conveying surface of magnetic identification sensor 200. However, if the conveying surface vibrates or deforms, the distance between the magnetic detection body and the magnetic medium changes, which appears as noise in the output of magnetic identification sensor 200, so the conveying surface must be structured to be resistant to vibration and deformation.

[0034] Furthermore, in future devices using the magnetic identification sensor 200, the transport speed of objects to be identified is expected to increase. Similarly, the frequency of filters installed in the control unit will also increase, and sensors will be required to handle higher vibration frequencies, increase identification speeds, and shorten identification times. The control units of existing products are equipped with low-pass filters with cutoff frequencies of several kHz to reduce noise. If the identification speed were to double or triple, the cutoff frequency would need to be increased to over 20 kHz. However, in sensor structures without a support for the sliding surface, the resonant frequency of the sliding surface is low (approximately 19 kHz), making it impossible to remove vibration components with a low-pass filter. As a result, vibration noise would be superimposed on the sensor output, making it impossible to shorten identification times. To achieve higher sensitivity than current models while shortening identification times, the resonant frequency of the sliding surface must be adjusted higher and appropriately controlled.

[0035] FIG. 9 is a conceptual diagram of the peripheral structure when the magnetic identification sensor 200 according to this embodiment is incorporated into a magnetic identification device (also called a host device) accompanied by a transport system 600 such as an ATM (Automatic Teller Machine).

[0036] The transport system 600 includes a group of devices for moving the magnetic medium 100 in the Ly direction on the sliding surface 211 of the magnetic identification sensor 200. The rotational motion obtained from the drive source 610 is transmitted to the roller 630 via the transmission system 620. The magnetic medium 100 is guided in the Ly direction by the rotation of the roller 630. Generally, the transport system 600 includes a single drive source 610 and multiple transmission systems 620 and rollers 630.

[0037] FIG. 10 is an explanatory diagram illustrating the shape of the rib (reinforcement portion) provided on the sliding portion 210. As shown in FIG.

[0038] 10A is a diagram showing ribs 212a provided at both ends of the sliding surface 211 of the sliding part 210. The ribs 212a are formed by bending the flat plate that constitutes the sliding surface 211 outside the sliding surface 211. As shown in the figure, the ribs 212a are formed by bending the ends of the sliding part 210 in a direction perpendicular to the moving direction of the magnetic medium in a direction that intersects with the sliding surface 211. As shown in FIGS. 10B and 10C, the height H of the ribs 212a is rb and length L rb is the exposed height H of the magnetic detection element 410 and the magnet 520 ex and exposure width L ex The opening depth H op and length L op It is desirable that it matches.

[0039] As a specific example of the ribs 212a, by providing ribs 212a with a width of 6.2 mm and a height of 1.0 mm on both sides of the sliding surface 211 while the opening width of the element holding member 420 is 6.8 mm, it is possible to raise the resonance frequency to 25.1 kHz. The shorter the width of the ribs 212a, the lower the resonance frequency, and it is 19.0 kHz without the ribs 212a. If the height of the ribs 212a is set to -0.3 mm (= 0.7 mm), the rigidity decreases and the resonance frequency drops to 24.3 kHz, while if the height is set to +0.3 mm (= 1.3 mm), the rigidity increases and the resonance frequency rises to 25.7 kHz.

[0040] Furthermore, since the resonant frequency is affected not only by the rigidity of the rib 212a but also by the mass of the rib 212a, in order to adjust the balance between these two elements, the ends of the rib 212a may be arched or trapezoidal, convex or concave, and may have a fold at the tip.

[0041] FIG. 11 is an explanatory diagram illustrating another shape of the rib (reinforcing portion) provided on the sliding portion 210. In FIG.

[0042] 11(A) is a diagram showing ribs 212b provided at two locations on the sliding surface 211 of the sliding part 210. In order to show the cross section of the sliding part 210, a part of the sliding part 210 is cut away in the diagram. The ribs 212b have a concave or convex shape, and are formed by drawing or half-blanking the flat plate that constitutes the sliding surface 211 within the sliding surface 211. As shown in FIGS. 11(B), (C), (D), and (E), the height H of the ribs 212b is dp , length L dp and width W dp are each equal to or greater than half the thickness of the flat plate, and the opening length L op , and the thickness of the plate or more to the width W of the opening provided in the element holding member 420 OP Up to half of this is desirable.

[0043] Vibrations are generated from the transport system 600 due to various rotational movements and due to the meshing of the transmission system 620. These vibrations are propagated to the magnetic identification sensor 200, causing the sliding part 210 to vibrate, which becomes a cause of output noise from the magnetic identification sensor 200. Furthermore, when the magnetic medium 100 is transported, vibrations are generated when the magnetic medium 100 collides with the roller 630 and the magnetic identification sensor 200. These vibrations also become a cause of output noise from the magnetic identification sensor 200.

[0044] The control unit of existing products is provided with a low-pass filter of several kHz to reduce this noise. In the case of the magnetic identification sensor 200 that does not have the rib 212 on the sliding part 210, the resonance frequency of the sliding surface is about 19 kHz, so the effective low-pass filter is about 19 kHz or less.

[0045] If the host device detects or identifies more magnetic media 100 per unit time or more quickly, the transport system 600 must be driven at a higher speed, generating proportionally higher-frequency vibrations. Therefore, the control unit must also be equipped with a similarly higher-frequency low-pass filter, and the sliding surface 211 must also have a correspondingly high resonant frequency. Specifically, if the amount of detection or identification required per unit time is two to three times that of an existing host device, the sliding surface 211 must have a resonant frequency of over 20 kHz. The sliding surface 210, which has a resonant frequency of approximately 19 kHz, cannot provide a sufficient noise reduction effect. Therefore, by providing the sliding portion 210 with a rib 212, the resonant frequency of the sliding surface 211 can be increased to approximately 25.1 kHz, thereby providing a sufficient noise reduction effect.

[0046] The above-described embodiments are merely examples of the present invention, and various modifications can be applied without departing from the spirit of the invention.

[0047] REFERENCE SIGNS LIST 100 Magnetic medium 110 Magnetic body 200 Magnetic identification sensor 210 Sliding portion 211 Sliding surface 300 Magnetic detection unit 400 Element unit 410 Magnetic detection element 411 Magnetic detection body 420 Element holding member 421 Guide surface 422 Guide surface 423 Guide surface 424 Guide surface 500 Magnet unit S Magnetic field range 520 Magnet 530 Magnet holding member 531 Guide surface 532 Guide surface 533 Guide surface 534 Guide surface

Claims

1. A magnetic identification sensor that moves a medium containing a magnetic material relatively along a transport surface and detects the magnetic pattern of the magnetic material, comprising a magnetic detection unit in which a first magnet and a magnetic detection element are arranged in order along the direction of movement of the medium relative to the transport surface, the magnetic detection element being fixed to a first holding member, and the first magnet being fixed to a second holding member having a guide surface that allows it to move relatively with the first holding member while restricting the direction of movement.

2. The magnetic identification sensor according to claim 1, wherein the guide surface allows the second holding member to move parallel to the conveying surface.

3. The magnetic identification sensor according to claim 1, wherein the guide surface allows the second holding member to move in a rotational direction around an imaginary point.

4. The magnetic identification sensor described in claim 1, further comprising a second magnet, wherein the first magnet, the magnetic detection element, and the second magnet are arranged in that order along the conveying surface, and the second magnet is fixed to the second holding member.

5. A magnetic identification sensor as described in claim 4, characterized in that the second holding member is provided between the first magnet and the second magnet and has a through hole in which the magnetic detection element is arranged, and the guide surface is an arcuate surface provided on the bottom of the second holding member.

6. A magnetic identification sensor as described in claim 1, further comprising a sliding part having the conveying surface and formed of a plate-like member, wherein the sliding part has a reinforcing part formed by bending the end of the sliding part in a direction perpendicular to the direction of movement of the medium in a direction intersecting the conveying surface.

7. A magnetic identification sensor as described in claim 6, further comprising a second magnet, the first magnet, the magnetic detection element, and the second magnet being arranged in that order along the conveying surface, and the length of the reinforcing part in the direction of movement of the medium or the length of the reinforcing part in the direction normal to the conveying surface, or both, is greater than or equal to the range including the first magnet, the magnetic detection element, and the second magnet.

8. A magnetic identification sensor as described in claim 1, further comprising a sliding portion having the conveying surface and formed of a plate-like member, wherein the sliding portion has a concave or convex reinforcing portion, or both, formed by drawing or half-punching within the range of the conveying surface.

9. The magnetic identification sensor according to claim 8, wherein the reinforcing portion is formed by drawing or half-blanking.

10. A magnetic identification sensor as described in claim 8, further comprising a second magnet, the first magnet, the magnetic detection element, and the second magnet being arranged in that order along the conveying surface, and the length of the reinforcing part in the direction of movement of the medium is equal to or greater than the range including the first magnet, the magnetic detection element, and the second magnet.

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