Paper type recognition device, paper type processing device, and paper type recognition method

Abstract

The problem lies in suppressing a reduction in the recognition accuracy of a paper-like object by a paper-like object recognition device. The solution lies in a paper-like object recognition device, a paper-like object processing device, and a paper-like object recognition method. The paper-like object recognition device recognizes a paper-like object and includes: a magnetic noise source that generates a changing magnetic field; a plurality of magnetic detection elements arranged in a vertical direction with respect to the surface of the paper-like object being conveyed on a conveyance path to detect the magnetism of the paper-like object; a magnetic member having a magnetic permeability of a specified value or more, disposed between the plurality of magnetic detection elements and the magnetic noise source; and an arithmetic unit that performs a differential operation on the magnetic detection values of the paper-like object being conveyed on the conveyance path based on the respective detection signals detected by the respective magnetic detection elements.

Description

Technical Field

[0001] The present invention relates to a paper-like object recognition device, a paper-like object processing device, and a paper-like object recognition method. Background Art

[0002] For example, a banknote processing device such as an automated teller machine (ATM) or an automated cash sorter has a banknote recognition device that discriminates the denomination, authenticity, dirt, crease, damage, etc. of banknotes. In the banknote recognition device, as one means for realizing the function of discriminating the denomination and authenticity of banknotes, a magnetic sensor is sometimes used. For example, in Patent Document 1, the difference between two magnetic sensor elements is obtained to remove magnetic noise of an external magnetic field, and the magnetism of a banknote is detected.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 6209674 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Magnetic noise that affects the banknote recognition device includes not only a uniform external magnetic field but also magnetic noise of a changing external magnetic field. However, in the prior art disclosed in Patent Document 1, although the magnetic noise of the uniform external magnetic field is removed, in the case of magnetic noise caused by a changing external magnetic field, it sometimes cannot be removed and is detected. As a result, magnetic noise overlaps in the detected magnetism of the banknote, and if a highly sensitive magnetic sensor is used, even the magnetic noise is detected.

[0008] That is, since a part of the banknote that should originally have no magnetic output is detected as having a magnetic output, the recognition accuracy of the banknote is reduced, and sometimes a banknote that should be accepted is excluded, or a banknote that should be excluded is accepted. Therefore, it is required to invalidate or reduce any interfering magnetic field and suppress the reduction in the recognition accuracy of banknotes.

[0009] In view of the above problems, an object of the present invention is to suppress a reduction in the recognition accuracy of a paper-like object recognition device for paper-like objects.

[0010] Means for Solving the Problems

[0011] In order to solve this problem, in the present invention, there is provided a paper-like object recognition device for recognizing paper-like objects, which is characterized by having: a magnetic noise source that generates a changing magnetic field; a plurality of magnetic detection elements arranged perpendicular to the surface of the paper-like object being conveyed on the conveyance path to detect the magnetism of the paper-like object; a magnetic member having a magnetic permeability of a specified value or more and disposed between the plurality of magnetic detection elements and the magnetic noise source; and an arithmetic unit that performs a differential operation on the magnetic detection values of the paper-like object being conveyed on the conveyance path based on the respective detection signals detected by the respective magnetic detection elements.

[0012] Advantages of the Invention

[0013] According to the present invention, for example, it is possible to suppress a decrease in the recognition accuracy of the paper-like object recognition device for paper-like objects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view of the appearance of the cash automatic transaction device according to the embodiment.

[0015] Figure 2 It is a schematic diagram showing the internal configuration of the cash automatic transaction device according to the embodiment.

[0016] Figure 3 It is a side view showing the main part of the configuration of the banknote recognition device according to the embodiment.

[0017] Figure 4 It is a plan view showing the main part of the configuration of the banknote recognition device according to the embodiment.

[0018] Figure 5 It is a functional block diagram showing the configuration of the banknote recognition device according to the embodiment.

[0019] Figure 6 It is a diagram for explaining the changing magnetic field in which the banknote recognition device is placed (in the case where there is no magnetic phase deviation mitigation plate).

[0020] Figure 7 It is a diagram for explaining the magnetic flux of the changing magnetic field passing through the differential magnetic sensor of the banknote recognition device (in the case where there is no magnetic phase deviation mitigation plate).

[0021] Figure 8 It is a diagram for explaining the component decomposition of the magnetic flux of the changing magnetic field detected by the differential magnetic sensor of the banknote recognition device (in the case where there is no magnetic phase deviation mitigation plate).

[0022] Figure 9 It is a diagram for explaining the magnetic flux of the changing magnetic field passing through two magnetic sensor elements of the differential magnetic sensor of the banknote recognition device (in the case where there is no magnetic phase deviation mitigation plate).

[0023] Figure 10 It is a diagram showing the magnetic flux change of the alternating magnetic field detected by two magnetic sensor elements of the differential magnetic sensor of the banknote recognition device (in the case without a magnetic phase deviation mitigation plate).

[0024] Figure 11 It is a diagram showing the alternating magnetic field in which the banknote recognition device is placed (in the case with a magnetic phase deviation mitigation plate).

[0025] Figure 12 It is a diagram showing the magnetic flux of the alternating magnetic field passing through the differential magnetic sensor of the banknote recognition device (in the case with a magnetic phase deviation mitigation plate).

[0026] Figure 13 It is a diagram showing the component decomposition of the magnetic flux of the alternating magnetic field detected by the differential magnetic sensor of the banknote recognition device (in the case with a magnetic phase deviation mitigation plate).

[0027] Figure 14 It is a diagram showing the magnetic flux of the alternating magnetic field passing through two magnetic sensor elements of the differential magnetic sensor of the banknote recognition device (in the case with a magnetic phase deviation mitigation plate).

[0028] Figure 15 It is a diagram showing the magnetic flux change of the alternating magnetic field detected by two magnetic sensor elements of the differential magnetic sensor of the banknote recognition device (in the case with a magnetic phase deviation mitigation plate).

[0029] Explanation of reference numerals:

[0030] 1... Cash automatic transaction device, 10... Banknote processing device, 30... Banknote recognition device, 30a... Conveyor path, 31a1, 31a2... Magnetic detection elements, 32a, 32b... Conveyor rollers, 32a1, 32b1... Driving rollers, 33a, 33b... Magnetic phase deviation mitigation plates, 35... Arithmetic unit Detailed implementation manners

[0031] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following embodiments including the drawings are merely illustrative and do not limit the present invention. In the following drawings for explaining the embodiments, the same reference numerals represent components or processes having the same or similar functions, and repeated explanations are omitted. In addition, in the scope of the technical idea of the present invention and within the scope of integration, some or all of the embodiments and each modification example can be combined.

[0032] In the following embodiments, the vertical direction (upper direction, upward) of the device housing of the cash automated transaction device is defined as the positive direction of the Z-axis, the direction from the user side (front side, front) to the opposite side (back side, rear) of the device housing of the cash automated transaction device is defined as the positive direction of the Y-axis, and the direction from left to right facing the user side of the cash automated transaction device is defined as the positive direction of the X-axis. Additionally, in the description of the following embodiments, an XYZ coordinate system of an orthogonal system in which the X-axis, Y-axis, and Z-axis are respectively orthogonal is used. Furthermore, in the following embodiments, the directions and positions expressed by terms such as "up", "down", "left", "right", "front", "rear", "back" are relative only, and the orientation, shape, or size of the cash automated transaction device, the banknote handling device, and other components are not limited by the XYZ coordinate system. Also, the number of components in the description and illustration of the embodiments is merely an example.

[0033] In the following embodiments, as examples of the paper handling device and the paper identification device, a cash automated transaction device or a banknote handling device that handles banknotes as paper, and a banknote identification device will be described as examples. However, it is not limited thereto, and various other papers such as checks or gift certificates can be handled in the same way.

[0034] (Overall configuration of the cash automated transaction device 1)

[0035] Figure 1 It is an external perspective view of the cash automated transaction device 1 according to the embodiment. The cash automated transaction device 1 uses a cash card, banknotes, receipts, etc. as transaction media, and performs processes such as cash deposit, payment, and remittance through the operation of the user. In the upper part inside the device housing of the cash automated transaction device 1, there are provided: a passbook processing mechanism (not shown) that processes the user's passbook, prints and discharges the transaction details; and a card and receipt processing mechanism (not shown) that processes the user's card, prints and discharges the transaction receipt.

[0036] The passbook processing mechanism processes the user's passbook inserted through the slot 2 on the front of the cash automated transaction device 1, and prints and discharges the transaction details. The card and receipt processing mechanism processes the user's card inserted through the slot 3 on the front of the cash automated transaction device 1, prints the transaction receipt and discharges it together with the card. In front of the cash automated transaction device 1, there is provided a screen operation unit 4 that displays the content of the user's transaction and inputs various information or items for the transaction.

[0037] In the lower part inside the device housing of the cash automated transaction device 1, there is provided a banknote handling device 10 that processes banknotes. Corresponding to the opening and closing of the opener 5a provided in the deposit and withdrawal section 5 of the banknote handling device 10, banknote deposit and withdrawal transactions are performed.

[0038] In addition, a coin processing device (not shown) for processing coins may also be provided inside the device housing of the cash automatic transaction device 1. Corresponding to the opening and closing of an opening / closing device (not shown) provided in the coin inlet / outlet section of the coin processing device, coin inlet / outlet transactions are performed.

[0039] (Internal configuration of the cash automatic transaction device 1)

[0040] Figure 2 It is a schematic diagram showing the internal configuration of the cash automatic transaction device 1 according to the embodiment. Above the upper part of the housing of the cash automatic transaction device 1, a processing mechanism for banknotes to be transacted is arranged, and a banknote storage mechanism is arranged below. Above the lower part of the housing of the banknote processing device 10, on its front side (the side facing the user: Figure 2 above the upper right side), a deposit / withdrawal section 5 is arranged. The deposit / withdrawal section 5 receives the deposit of banknotes placed by the user in a substantially upright posture and discharges the banknotes placed in a substantially upright posture for the user to take out. In addition, a banknote identification device 30 for discriminating banknotes is arranged in the central part, and a temporary storage section 40 is arranged at the rear side ( Figure 2 above the upper left side). The temporary storage section 40 temporarily stores the banknotes deposited by the user until the transaction is completed. The above-mentioned respective mechanism sections are connected by a two-way conveyance path.

[0041] The banknote identification device 30 can perform currency discrimination and authenticity discrimination on banknotes conveyed on the conveyance path 30a from the front and the rear, regardless of the direction. The banknote identification device 30 can perform currency discrimination and authenticity discrimination on banknotes conveyed in both the deposit and withdrawal directions, and can discriminate whether the banknote can be accepted and whether it can be withdrawn. In the deposit / withdrawal section 5, a banknote delivery section 5b for delivering the banknotes dropped from above downward and a banknote accumulation section 5c for accumulating the banknotes conveyed from below for withdrawal or return are arranged in the front and rear.

[0042] Below the banknote processing device 10, a plurality of storage sections 70 for storing banknotes by currency are arranged. Among the storage sections 70, there are a storage section for storing the banknotes determined by the banknote identification device 30 to be acceptable by currency, a storage section for temporarily storing the banknotes determined by the banknote identification device 30 not to be acceptable, a storage section for storing the banknotes determined by the banknote identification device 30 not to be withdrawable, a storage section used when replenishing banknotes from the outside for withdrawal, and the like.

[0043] (Configuration of the banknote identification device 30)

[0044] Figure 3 It is a side view showing the main part of the configuration of the banknote identification device 30 according to the embodiment. Figure 4It is a plan view of the main part showing the configuration of the banknote recognition device 30 according to the embodiment. In addition to the illustrations of Figure 3 and Figure 4 the banknote recognition device 30 also includes various sensors such as a thickness sensor, a drive motor for the conveying rollers, and other conveying rollers, etc., but the illustrations are omitted.

[0045] The banknote recognition device 30 is configured to include a conveying guide 30b, a recognition sensor 31, conveying rollers 32a, 32b, drive rollers 32a1, 32b1, 32c1, and magnetic phase deviation mitigation plates 33a, 33b. A plurality of conveying rollers 32a are arranged in the X-axis direction on the positive Y-axis side of the recognition sensor 31. In addition, a plurality of conveying rollers 32b are arranged in the X-axis direction on the negative Y-axis side of the recognition sensor 31.

[0046] The conveying rollers 32a, 32b are rotated by the drive rollers 32a1, 32b1 that are rotated by the drive of a drive motor (not shown). The banknotes on the conveying path 30a are clamped by the conveying rollers 32a, 32b and the drive rollers 32a1, 32b1 opposed to the conveying rollers 32a, 32b and conveyed in the positive and negative directions of the Y-axis. The conveying rollers 32a, 32b are, for example, magnetized magnetic bodies such as bearing rollers, and by rotating about the rotation axis, the magnetic poles rotate to generate a changing magnetic field.

[0047] The recognition sensor 31 has a plurality of differential magnetic sensors 31a, and the plurality of differential magnetic sensors 31a include magnetic detection elements 31a1, 31a2 arranged in the Z-axis direction. The Z-axis direction is the direction perpendicular to the surface of the banknote conveyed on the conveying path 30a, and is the magnetic detection direction of the differential magnetic sensors 31a (magnetic detection elements 31a1, 31a2). The plurality of differential magnetic sensors 31a are arranged in an array in the X-axis direction within the recognition sensor 31 to form a sensor array 31A. The drive roller 32c1 presses the banknote on the recognition sensor 31 with a gap that does not cause paper jams and conveys it.

[0048] The magnetic phase deviation mitigation plates 33a, 33b are respectively provided between the recognition sensor 31 and the conveying rollers 32a, 32b. The magnetic phase deviation mitigation plates 33a, 33b are plate-shaped magnetic members with a magnetic permeability of a specified value or more, and are arranged such that the long sides extend in a direction (X-axis direction, sensor array 31A direction) orthogonal to the magnetic detection direction (Z-axis direction, magnetic field detection direction) of the magnetic detection elements 31a1, 31a2.

[0049] In addition, the magnetic phase deviation mitigation plates 33a and 33b are arranged at positions where the magnetic fluxes reaching the magnetic detection elements 31a1 and 31a2 among the magnetic flux paths formed by the transport rollers 32a and 32b are bent and aligned in the most consistent direction between the transport rollers 32a and 32b and the magnetic detection elements 31a1 and 31a2. In addition, the magnetic phase deviation mitigation plates 33a and 33b are arranged with an orientation orthogonal to the magnetic field detection direction of the magnetic detection elements 31a1 and 31a2, so that the magnetic fluxes reaching the magnetic detection elements 31a1 and 31a2 among the magnetic flux paths formed by the transport rollers 32a and 32b are bent and aligned in a direction perpendicular to the arrangement direction (magnetic field detection direction) of the magnetic detection elements 31a1 and 31a2. Thus, the magnetic phase deviation mitigation plates 33a and 33b do not need to be arranged near the magnetic detection elements 31a1 and 31a2. In addition, by aligning the magnetic fluxes in a direction perpendicular to the arrangement direction of the magnetic detection elements 31a1 and 31a2, it is possible to detour and reduce the magnetic field acting on the magnetic detection elements 31a1 and 31a2. Even without arranging a magnetic member (so-called magnetic shielding) very close to the magnetic detection elements 31a1 and 31a2 to reduce the magnetic flux reaching the magnetic detection elements 31a1 and 31a2, it is possible to effectively reduce the phase deviation and improve the differential effect.

[0050] In addition, the length in the longitudinal direction (X-axis direction) of the magnetic phase deviation mitigation plates 33a and 33b is a length within a range that can maintain the characteristics of the differential magnetic sensor 31a at a certain level or above regardless of the DC magnetic field caused by the magnetic poles generated by the magnetic phase deviation mitigation plates 33a and 33b. The longer the magnetic phase deviation mitigation plates 33a and 33b are in the longitudinal direction (X-axis direction), the more the magnetic fluxes reaching the magnetic detection elements 31a1 and 31a2 can be bent in a direction perpendicular to the arrangement direction of the magnetic detection elements 31a1 and 31a2. On the other hand, the longer they are, the easier it is to generate magnetic poles at both ends and the easier it is for their magnetic fields to spread far away, and sometimes the characteristics of the differential magnetic sensor 31a cannot be maintained in this DC magnetic field. Therefore, the length in the longitudinal direction (X-axis direction) is selected within the range for maintaining the characteristics. In addition, the length in the short side direction (Z-axis direction) and the thickness (Y-axis direction) of the magnetic phase deviation mitigation plates 33a and 33b only need to be within a range where they do not interfere with other components in the housing of the banknote identification device 30 and within a range where magnetic saturation does not occur.

[0051] In addition, the magnetic phase deviation mitigation plates 33a and 33b are made of a soft magnetic material with a permeability of a certain level or above selected from a group of materials including permalloy and non-oriented silicon steel sheets. The soft magnetic material is preferably heat-treated to reduce the coercive force so that it is not easy to generate magnetic poles in the longitudinal direction.

[0052] (Functional Configuration of Banknote Recognition Device 30)

[0053] Figure 5 It is a functional block diagram showing the configuration of the banknote recognition device 30. In addition to the above configuration, the banknote recognition device 30 also has amplifiers 331 and 332 such as operational amplifiers, AD (Analog to Digital) converters 341 and 342, and an arithmetic unit 35 such as a microcomputer.

[0054] The amplifier 331 amplifies the detection signal of the magnetic detection element 31a1. The amplifier 332 amplifies the detection signal of the magnetic detection element 31a2. The AD converter 341 digitizes the detection signal amplified by the amplifier 331. The AD converter 342 digitizes the detection signal amplified by the amplifier 332. The arithmetic unit 35 calculates the banknote magnetic detection value α1×V1(nT) - α2×V2(nT) based on the AD conversion values V1(nT) and V2(nT) of the detection signals digitized by the AD converters 341 and 342. Here, n is a natural number starting from 0 according to the sampling sequence number, T is the sampling period, and α1 and α2 are specified quantities.

[0055] As described later, the banknote magnetic detection value α1×V1(nT) - α2×V2(nT) in the present embodiment becomes a value obtained by performing sensitivity correction on the magnetic detection elements 31a1 and 31a2 and eliminating the magnetic noise of the uniform magnetic field and the fluctuating magnetic field.

[0056] (Phase Difference of Magnetic Flux in the Magnetic Detection Direction)

[0057] Hereinafter, with reference to Figures 6 to 10 and Figures 11 to 15 , the present embodiment is used to illustrate the case where the phase difference of the magnetic flux in the magnetic detection directions of the magnetic detection elements 31a1 and 31a2 becomes smaller. Figures 6 to 10 represents the case without the magnetic phase deviation mitigation plates 33a and 33b (prior art), Figures 11 to 15 represents the case with the magnetic phase deviation mitigation plates 33a and 33b (the present embodiment).

[0058] (Regarding the Case without Magnetic Phase Deviation Mitigation Plates 33a and 33b)

[0059] First, with reference to Figures 6 to 10 , the case without the magnetic phase deviation mitigation plates 33a and 33b (prior art) is described.

[0060] As the magnetic flux of the banknote on the conveyance path 30a passing near the magnetic detection elements 31a1 and 31a2, the detected value V1 (nT) of the upper magnetic detection element 31a1 closer to the banknote is larger than the detected value V2 (nT) of the lower magnetic detection element 31a2 farther from the banknote. Thus, generally, by calculating the difference V1 (nT) - V2 (nT) of the detected values, a detection signal of the magnetic flux of the banknote on the conveyance path 30a passing near the magnetic detection elements 31a1 and 31a2 can be obtained.

[0061] The magnetic noise source of the uniform magnetic field is located at a relatively far position compared to the banknote on the conveyance path 30a passing near the magnetic detection elements 31a1 and 31a2. Thus, the distances from the magnetic noise source to the magnetic detection elements 31a1 and 31a2 are substantially equal. Accordingly, the magnetic noise of the uniform magnetic field can be regarded as being uniformly superimposed on the detected values V1 (nT) and V2 (nT) of the magnetic detection elements 31a1 and 31a2, and thus is eliminated by obtaining the difference V1 (nT) - V2 (nT) of the detected values.

[0062] When there are deviations in sensitivity between the upper and lower magnetic detection elements 31a1 and 31a2, a uniform magnetic field is applied in the detection directions of the magnetic detection elements 31a1 and 31a2, and correction coefficients α1 and α2 for correcting the sensitivity are calculated in advance so that the amplitude values V1 and V2 of the detection signals of the magnetic detection elements 31a1 and 31a2 are the same. Then, by calculating α1 × V1 (nT) ― α2 × V2 (nT), a detection signal with corrected sensitivity and eliminated magnetic noise can be obtained.

[0063] Figure 6 This is a diagram for explaining the alternating magnetic field in which the banknote recognition device 30 is placed (in the case where there are no magnetic phase deviation mitigation plates 33a and 33b). However, as Figure 6 shown, in the structure of the conveyance path 30a, when a slightly magnetized rotating body (the conveyance roller 32b in Figure 6 ) needs to be arranged near the differential magnetic sensor 31a, a phase difference is generated in the magnetic flux reaching the upper and lower magnetic detection elements 31a1 and 31a2, and interference noise cannot be eliminated.

[0064] The reason for the phase difference in the magnetic flux reaching the upper and lower magnetic detection elements 31a1 and 31a2 is as follows. Figure 7 This is a diagram for explaining the magnetic flux of the alternating magnetic field passing through the differential magnetic sensor 31a of the banknote recognition device 30 (in the case where there are no magnetic phase deviation mitigation plates 33a and 33b). As Figure 7As shown, the orientation and magnitude of the magnetic field vector H caused by the magnetic flux near the sensor center Δ = 0 (the center line of the magnetic detection elements 31a1 and 31a2) between the magnetic detection elements 31a1 and 31a2 change according to the rotation angle θ of the transport roller 32b. In this change, the orientation and magnitude of the magnetic field vector H are determined according to the distances from the magnetic poles S and N of the transport roller 32b. The closer the distance to the magnetic poles S and N, the larger the magnetic field vector H.

[0065] Figure 8 It is a diagram (in the case without the magnetic phase deviation mitigation plates 33a and 33b) for explaining the component decomposition of the magnetic flux of the alternating magnetic field detected by the differential magnetic sensor 31a of the banknote identification device 30. However, in Figure 8 the component of the magnetic field vector H in the direction of the sensor array 31A is omitted. As Figure 8 shown, the magnetic field vector H can be decomposed into a banknote transport direction component vector Hy on the transport path 30a and a magnetic field detection direction component vector Hz of the differential magnetic sensor 31a.

[0066] The orientation and magnitude of the magnetic field vector H are determined according to the distance L from the magnetic poles S and N of the transport roller 32b (refer to Figure 7 ). The distance L changes periodically according to the rotation angle θ of the transport roller 32b (θ is the angle formed by the magnetization direction from S to N of the transport roller 32b and the positive direction of the Z axis). Therefore, the orientation and magnitude of the magnetic field vector H and the magnetic field detection direction component vector Hz change periodically according to the rotation angle θ of the transport roller 32b.

[0067] Figure 9 It is a diagram (in the case without the magnetic phase deviation mitigation plates 33a and 33b) for explaining the magnetic flux of the alternating magnetic field passing through the two magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the banknote identification device 30. The magnetic detection element 31a1 and the magnetic detection element 31a2 are separated from the sensor center Δ = 0 along the magnetic field detection direction (Z-axis direction) by an element-to-element distance of ±Δd / 2. Due to the difference in their positions, the orientations of the magnetic field vectors H1 of the magnetic detection element 31a1 and H2 of the magnetic detection element 31a2 are different from the magnetic field vector H at the center of the sensor element respectively.

[0068] Therefore, for example, when the rotation angle θ = 0°, the magnitude |H1z| of the magnetic field detection direction component vector H1z of the magnetic field vector H1 of the magnetic detection element 31a1 is smaller than the magnitude |Hz| of the magnetic field detection direction component vector Hz of the magnetic field vector H at the sensor center Δ = 0. In addition, when the rotation angle θ = 0°, the magnitude |H2z| of the magnetic field detection direction component vector H2z of the magnetic field vector H2 of the magnetic detection element 31a2 is larger than the magnitude |Hz| of the magnetic field detection direction component vector Hz of the magnetic field vector H at the sensor center Δ = 0. This difference is determined by the action of the surrounding magnetic moments.

[0069] Compared with the magnetic field detection direction component vector Hz, the magnetic field detection direction component vector H1z undergoes the same periodic change, but the timing of reaching the same magnitude is later. The magnetic field detection direction component vector H1z seems to have a phase delay compared to the magnetic field detection direction component vector Hz. In addition, compared with the magnetic field detection direction component vector Hz, the magnetic field detection direction component vector H2z undergoes the same periodic change, but the timing of reaching the same magnitude is earlier. The magnetic field detection direction component vector H2z seems to have a phase advance compared to the magnetic field detection direction component vector Hz.

[0070] Figure 10 It is a diagram (in the case without the magnetic phase deviation mitigation plates 33a and 33b) for explaining the magnetic flux change of the alternating magnetic field detected by the two magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the banknote identification device 30. In this way, between the magnetic field detection direction component vectors H1z and H2z of the magnetic detection element 31a1 and the magnetic detection element 31a2, as Figure 10 shown, a phase difference is generated in the alternating magnetic field caused by the rotation of the transport roller 32b.

[0071] As a result, in the banknote magnetic detection value α1×V1(nT) ― α2×V2(nT) calculated using the detection value V1(nT) obtained by detecting the magnetic field detection direction component vector H1z and the detection value V2(nT) obtained by detecting the magnetic field detection direction component vector H2z, magnetic noise from the external noise source generating the alternating magnetic field remains in an amount corresponding to the phase difference.

[0072] (Regarding the case with the magnetic phase deviation mitigation plates 33a and 33b)

[0073] Next, with reference to Figures 11 to 15 , the case with the magnetic phase deviation mitigation plates 33a and 33b (this embodiment) will be described.

[0074] Figure 11 It is a diagram for explaining the alternating magnetic field in which the banknote identification device 30 is placed (in the case with the magnetic phase deviation mitigation plates 33a and 33b). As Figure 11As shown, in the present embodiment, a magnetic phase deviation mitigation plate 33b is provided between the differential magnetic sensor 31a and the conveying roller 32b. In this case, the magnetic flux detected by the differential magnetic sensor 31a is attracted close to the magnetic phase deviation mitigation plate 33b and skews so as to be parallel to the length direction (X-axis direction) of the magnetic phase deviation mitigation plate 33b.

[0075] Figure 12 It is a diagram for explaining the magnetic flux of the alternating magnetic field passing through the differential magnetic sensor 31a of the banknote identification device 30 (in the case where there are magnetic phase deviation mitigation plates 33a and 33b). As a result, as Figure 12 shown, the magnetic field vector H' caused by the magnetic flux near the sensor center Δ = 0 between the magnetic detection elements 31a1 and 31a2 is oriented in the length direction of the magnetic phase deviation mitigation plate 33b so as to be parallel to the magnetic phase deviation mitigation plate 33b.

[0076] Figure 13 It is a diagram for explaining the component decomposition of the magnetic flux of the alternating magnetic field detected by the differential magnetic sensor 31a of the banknote identification device 30 (in the case where there are magnetic phase deviation mitigation plates 33a and 33b). However, in Figure 13 it, the component of the magnetic field vector H' in the direction of the sensor array 31A is omitted from the illustration. As Figure 13 shown, the magnetic field vector H' can be decomposed into a banknote conveying direction component vector H'y on the conveying path 30a and a magnetic field detection direction component vector H'z of the differential magnetic sensor 31a.

[0077] The orientation and magnitude of the magnetic field vector H' and the magnetic field detection direction component vector H'z are the same as those of the magnetic field vector H and the magnetic field detection direction component vector Hz, and vary periodically according to the rotation angle θ of the conveying roller 32b. In addition, the magnitude |H'z| of the magnetic field detection direction component vector H'z becomes a value smaller than the magnitude |Hz| of the magnetic field detection direction component vector Hz in the case where there are no magnetic phase deviation mitigation plates 33a and 33b. |H’z| is smaller than |Hz| because the magnetic phase deviation mitigation plates 33a and 33b attract the magnetic flux, resulting in a reduction in the magnetic field lines, or because the magnetic flux from a distance, which is originally of a smaller intensity, approaches and reaches the element.

[0078] Figure 14This is a diagram for explaining the magnetic flux of the alternating magnetic field detected by two magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the banknote recognition device 30 (in the case where there are magnetic phase deviation mitigation plates 33a and 33b). If a magnetic phase deviation mitigation plate 33b is provided between the differential magnetic sensor 31a and the transport roller 32b, a force acts to align the directions of the magnetic fields passing through the two magnetic detection elements 31a1 and 31a2 to be consistent with the direction of the sensor array 31A regardless of the position within ±Δd / 2.

[0079] Therefore, for example, when the rotation angle θ = 0°, the magnitudes |H1′z| of the magnetic field detection direction component vectors H1′z of the magnetic field vector H1 of the magnetic detection element 31a1, the magnitude |H′z| of the magnetic field detection direction component vector H′z of the magnetic field vector H′ at the sensor center, and the magnitude |H2′z| of the magnetic field detection direction component vector H2′z of the magnetic field vector H2 of the magnetic detection element 31a2 all become substantially the same. In addition, the above |H1′z|, |H′z|, and |H2′z| become values smaller than |H1z|, |Hz|, and |H2z| in the case where there are no magnetic phase deviation mitigation plates 33a and 33b (prior art). The reason why |H1′z|, |H′z|, and |H2′z| are smaller than |H1z|, |Hz|, and |H2z| is that the magnetic phase deviation mitigation plates 33a and 33b attract the magnetic flux, resulting in a reduction in the magnetic field lines, or the magnetic flux in the distance, which is originally of a small intensity, approaches and reaches the elements.

[0080] As a result, compared with the case where there are no magnetic phase deviation mitigation plates 33a and 33b (prior art), the magnetic field detection direction component vectors H1′z and H2′z undergo the same periodic change as the magnetic field detection direction component vector H′z, and the phase difference is also approximately 0.

[0081] Figure 15 This is a diagram for explaining the change in the magnetic flux of the alternating magnetic field detected by two magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the banknote recognition device 30 (in the case where there are magnetic phase deviation mitigation plates 33a and 33b). That is, as Figure 15 shown, the phase difference between the magnetic field detection direction component vectors H1′z and H2′z of the magnetic flux detected by the magnetic detection elements 31a1 and 31a2 due to the transport roller 32b is approximately 0.

[0082] Accordingly, when calculating the banknote magnetic detection value α1×V1(nT)―α2×V2(nT) using the detection value V1(nT) obtained by detecting the magnetic field detection direction component vector H1′z and the detection value V2(nT) obtained by detecting the magnetic field detection direction component vector H2′z in the same way as before, magnetic noise from an external noise source that generates a fluctuating magnetic field can be eliminated. That is, the banknote identification device 30 has the same configuration as the conventional banknote identification device except for adding the magnetic phase deviation mitigation plates 33a and 33b.

[0083] In addition, through experiments, it is known that the longer the magnetic phase deviation mitigation plates 33a and 33b are in the direction of the sensor array 31A, the more the direction of the magnetic field at Δ≤±Δd / 2 between the magnetic detection elements 31a1 and 31a2 is made to coincide with the direction of the sensor array 31A. Thus, it can be said that the longer the magnetic phase deviation mitigation plates 33a and 33b are in the direction of the sensor array 31A, the better the effect of reducing external noise from an external noise source that generates a fluctuating magnetic field.

[0084] (Other Embodiments)

[0085] As another embodiment, a paper-like material identification method performed by a paper-like material identification device will be described.

[0086] A paper-like material identification device (e.g., the banknote identification device 30) includes: a magnetic noise source that generates a fluctuating magnetic field (e.g., the transport rollers 32a, 32b, and the drive rollers 32a1, 32b1), a transport path (e.g., the transport path 30a) for transporting paper-like materials (e.g., banknotes), a plurality of magnetic detection elements (e.g., the magnetic detection elements 31a1, 31a2) arranged perpendicular to the surface of the paper-like material being transported on the transport path and for detecting the magnetism of the paper-like material, and an arithmetic unit (e.g., the arithmetic unit 35) that calculates a differential detection value based on the detection signals detected by each magnetic detection element.

[0087] In the paper-like material identification method of this paper-like material identification device, a magnetic component (e.g., the magnetic phase deviation mitigation plates 33a and 33b) having a magnetic permeability of a specified value or more and a shape with a long side extending in the width direction of the transport path is disposed between the plurality of magnetic detection elements and the magnetic noise source. Then, the plurality of magnetic detection elements detect the magnetism of the paper-like material being transported on the transport path, and the arithmetic unit calculates the differential detection value of the paper-like material being transported on the transport path based on the detection signals detected by each magnetic detection element.

[0088] According to the above-described embodiment, a magnetic member having a magnetic permeability equal to or higher than a specified value is disposed between a plurality of magnetic detection elements and a magnetic noise source. Thereby, without changing the calculation method of the magnetic detection value of the banknote α1×V1 (nT) - α2×V2 (nT), it is possible to suppress magnetic noise caused by a magnetic noise source that generates a variable magnetic field and improve the tolerance to external magnetic noise with a simple configuration, and detect the magnetism of the banknote with high precision. As a result, the accuracy of authenticity determination of the banknote can be improved. In addition, the yield of magnetization screening of components of the conveying mechanism can be improved.

[0089] In addition, compared with the case where the periphery of the element is magnetically shielded using a plate material having a high magnetic permeability, the magnetic field of the sensor magnetic circuit is not disturbed, so that expected characteristics can be obtained even when a highly sensitive magnetic detection element is used.

[0090] Furthermore, the present invention is not limited to the above-described embodiment, and includes various modification examples. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, but is not limited to having all the configurations described. In addition, as long as there is no contradiction, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, or the configuration of another embodiment can be added to the configuration of a certain embodiment. In addition, addition, deletion, replacement, integration, and division can be performed on a part of the configuration of each embodiment. In addition, each process shown in the embodiment can be appropriately dispersed or integrated based on processing efficiency or installation efficiency.

Claims

1. A paper type recognition device for recognizing paper types, characterized in that, comprising: a magnetic noise source that generates a changing magnetic field; a plurality of magnetic detection elements arranged perpendicular to the surface of the paper-like material being conveyed on the conveyance path, for detecting the magnetism of the paper-like material; a magnetic member having a magnetic permeability of a specified value or more, and disposed between the plurality of magnetic detection elements and the magnetic noise source; and an arithmetic unit that performs a differential operation on the magnetic detection values of the paper-like material being conveyed on the conveyance path based on the respective detection signals detected by the respective magnetic detection elements, the magnetic member is disposed at a position where the path of the magnetic flux passing through the plurality of magnetic detection elements is bent and aligned in a direction perpendicular to the arrangement direction of the plurality of magnetic detection elements.

2. The paper-like material identification device according to claim 1, wherein the magnetic noise source includes a conveyance roller that rotates following a drive roller and conveys the paper-like material, and the shaft of the drive roller.

3. The paper-like material identification device according to claim 1, wherein the magnetic member has a shape with a long side extending in the width direction of the conveyance path.

4. The paper-like material identification device according to claim 3, wherein the length of the long side of the magnetic member is within a range where the magnetic detection characteristics of the plurality of magnetic detection elements can be maintained at a certain level or more regardless of the DC magnetic field caused by the magnetic poles generated by the magnetic member.

5. The paper-like material identification device according to claim 1, wherein the magnetic member is disposed in an orientation orthogonal to the magnetic field detection direction of the plurality of magnetic detection elements.

6. The paper-like material identification device according to claim 1, wherein the magnetic member is a soft magnetic material selected from a group of materials including permalloy and non-oriented silicon steel sheet.

7. The paper-like material identification device according to claim 6, wherein the soft magnetic material has been heat-treated.

8. A paper processing device, characterized in that, There is a paper-like material identification device according to any one of claims 1 to 7.

9. A method for identifying a paper-like material, for identifying a paper-like material, characterized in that in a paper-like material identification device having a magnetic noise source that generates a changing magnetic field, a plurality of magnetic detection elements arranged perpendicular to the surface of the paper-like material being conveyed on the conveyance path and detecting the magnetism of the paper-like material, and an arithmetic unit that performs an operation on the differential detection values of the paper-like material being conveyed on the conveyance path based on the respective detection signals detected by the respective magnetic detection elements, a magnetic member is disposed between the plurality of magnetic detection elements and the magnetic noise source, the magnetic member has a magnetic permeability of a specified value or more, and the magnetic member has a shape with a long side extending in the width direction of the conveyance path orthogonal to the magnetic field detection direction of the plurality of magnetic detection elements, the magnetic member is disposed at a position where the path of the magnetic flux passing through the plurality of magnetic detection elements is bent and aligned in a direction perpendicular to the arrangement direction of the plurality of magnetic detection elements, the plurality of magnetic detection elements detect the magnetism of the paper-like material being conveyed on the conveyance path, The arithmetic unit performs a difference operation on the magnetic detection values of the paper-like materials being transported on the transport path based on the respective detection signals detected by the respective magnetic detection elements.

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