CN115995126A - Paper sheet identification device, paper sheet processing device, and paper sheet identification method - Google Patents

Abstract

The object is to suppress a decrease in the accuracy of recognizing a sheet by a sheet recognizing device. The paper sheet identifying device identifies paper sheets, and includes: a magnetic noise source for generating a fluctuating magnetic field; a plurality of magnetic detection elements arranged in a vertical direction with respect to a surface of a sheet being conveyed on a conveying path, for detecting magnetism of the sheet; a magnetic member having a magnetic permeability of at least a predetermined value and disposed between the plurality of magnetic detection elements and the magnetic noise source; and an arithmetic unit for performing a difference operation on the magnetic detection value of the paper sheet conveyed on the conveying path based on each detection signal detected by each magnetic detection element.

Description

Paper sheet identification device, paper sheet processing device, and paper sheet identification method

Technical Field

The present invention relates to a sheet identifying device, a sheet processing device, and a sheet identifying method.

Background

Banknote handling devices such as automatic teller machines (ATM: automated Teller Machine) and automatic cash sorters (sorters) include banknote discriminating devices for discriminating the types, authenticity, stains, folds, and damage of banknotes. In a banknote discriminating device, a magnetic sensor is used as one of the means for realizing the function of discriminating the denomination and authenticity of a banknote. For example, in patent document 1, a difference between two magnetic sensor elements is obtained, magnetic noise of an external magnetic field is removed, and magnetism of paper money is detected.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 6209674

Disclosure of Invention

Problems to be solved by the invention

The magnetic noise affecting the bill discriminating device includes, in addition to the uniform external magnetic field, the magnetic noise of the varying external magnetic field. However, in the conventional technique disclosed in patent document 1, although the magnetic noise of the uniform external magnetic field is removed, the magnetic noise may not be removed and detected in the case of the magnetic noise due to the fluctuating external magnetic field. As a result, magnetic noise is superimposed on the magnetism of the detected bill, and if a magnetic sensor having high sensitivity is used, even the magnetic noise is detected.

That is, since a portion of the banknote that should not be magnetically output is detected as magnetically output, the recognition accuracy of the banknote is lowered, and the banknote to be accepted may be removed or the banknote to be removed may be accepted. Therefore, it is required to invalidate or reduce any disturbing magnetic field and suppress the deterioration of the recognition accuracy of the banknote.

In view of the above problems, an object of the present invention is to suppress a decrease in the accuracy of recognizing a sheet by a sheet recognizing device.

Means for solving the problems

In order to solve the problem, the present invention provides a paper sheet identifying device for identifying paper sheets, comprising: a magnetic noise source for generating a fluctuating magnetic field; a plurality of magnetic detection elements arranged in a vertical direction with respect to a surface of a sheet being conveyed on a conveying path, for detecting magnetism of the sheet; a magnetic member having a magnetic permeability of a predetermined or more and disposed between the plurality of magnetic detection elements and the magnetic noise source; and an arithmetic unit that performs a difference operation on the magnetic detection value of the sheet conveyed on the conveying path based on each detection signal detected by each of the magnetic detection elements.

Effects of the invention

According to the present invention, for example, a decrease in the accuracy of recognizing a sheet by the sheet recognizing device can be suppressed.

Drawings

Fig. 1 is an external oblique view of an automatic cash transaction apparatus according to an embodiment.

Fig. 2 is a schematic diagram showing an internal configuration of the automatic cash transaction apparatus according to the embodiment.

Fig. 3 is a side view showing a main part of the structure of the banknote discriminating apparatus according to the embodiment.

Fig. 4 is a plan view showing a main part of the structure of the banknote discriminating apparatus according to the embodiment.

Fig. 5 is a functional block diagram showing the structure of the banknote discriminating device according to the embodiment.

Fig. 6 is a diagram for explaining a fluctuating magnetic field (in the case where there is no magnetic phase deviation alleviation plate) in which the banknote discriminating device is placed.

Fig. 7 is a diagram for explaining the magnetic flux of the varying magnetic field passing through the differential magnetic sensor of the bill discriminating device (in the case where the magnetic phase deviation alleviation plate is not provided).

Fig. 8 is a diagram for explaining component decomposition of the magnetic flux of the varying magnetic field detected by the differential magnetic sensor of the bill discriminating device (in the case where the magnetic phase deviation alleviation plate is not provided).

Fig. 9 is a diagram for explaining the magnetic fluxes of the varying magnetic fields passing through the 2 magnetic sensor elements of the differential magnetic sensor of the bill discriminating device (in the case where there is no magnetic phase deviation alleviation plate).

Fig. 10 is a diagram for explaining the magnetic flux fluctuation of the fluctuation magnetic field detected by 2 magnetic sensor elements of the differential magnetic sensor of the bill discriminating device (in the case where there is no magnetic phase deviation alleviation plate).

Fig. 11 is a diagram for explaining a fluctuating magnetic field (in the case of a magnetic phase deviation reducing plate) in which the banknote discriminating device is placed.

Fig. 12 is a diagram for explaining the magnetic flux of the varying magnetic field passing through the differential magnetic sensor of the bill discriminating device (in the case of the magnetic phase deviation alleviating plate).

Fig. 13 is a diagram for explaining component decomposition of the magnetic flux of the varying magnetic field detected by the differential magnetic sensor of the bill discriminating device (in the case of the magnetic phase deviation alleviating plate).

Fig. 14 is a diagram for explaining the magnetic fluxes of the varying magnetic fields passing through the 2 magnetic sensor elements of the differential magnetic sensor of the bill discriminating device (in the case of the magnetic phase deviation alleviation plate).

Fig. 15 is a diagram for explaining the magnetic flux fluctuation of the fluctuation magnetic field detected by 2 magnetic sensor elements of the differential magnetic sensor of the bill discriminating device (in the case of the magnetic phase deviation alleviation plate).

Reference numerals illustrate:

1 … … Cash automatic transaction device, 10 … … paper money handling device, 30 … … paper money discriminating device, 30a … … conveying path, 31a1, 31a2 … … magnetic detection element, 32a, 32b … … conveying roller, 32a1, 32b1 … … driving roller, 33a, 33b … … magnetic phase deviation relieving plate, 35 … … arithmetic unit

Detailed Description

Embodiments of the present invention will be described below in detail based on the drawings. The following embodiments are merely examples including the drawings, and do not limit the present invention. In the drawings for describing the embodiments below, the same reference numerals denote components or processes having the same or similar functions, and a repetitive description thereof will be omitted. The embodiments and the modifications may be partially or entirely combined within the scope of the technical idea of the present invention and within the scope of integration.

In the following embodiments, the vertical direction (upper direction ) of the device case of the automatic cash transaction device is defined as the positive direction of the Z axis, the direction from the user side (front side, front) toward the opposite side (back side, rear) of the device case of the automatic cash transaction device is defined as the positive direction of the Y axis, and the direction from the left side toward the right side of the device case of the automatic cash transaction device is defined as the positive direction of the X axis. In the following description of the embodiment, an XYZ coordinate system of an orthogonal system in which the X axis, the Y axis, and the Z axis are orthogonal to each other is used. In the following embodiments, directions and positions expressed by "up", "down", "left", "right", "front", "rear", "back", and the like are merely relative, and directions, shapes, and sizes of the automatic cash transaction device, the banknote handling device, and other components are not limited by the XYZ coordinate system. The number of constituent elements in the description and the drawings of the embodiment is merely an example.

In the following embodiments, as examples of the paper sheet handling device and the paper sheet discriminating device, an automatic cash transaction device or a paper sheet handling device, which handle paper money as paper sheets, and a paper sheet discriminating device will be described as examples. However, the present invention is not limited to this, and other various types of paper such as checks and coupons can be similarly processed.

(integral Structure of automatic Cash transaction device 1)

Fig. 1 is an external oblique view of an automatic cash transaction apparatus 1 according to an embodiment. The automatic cash transaction apparatus 1 uses cash cards, banknotes, vouchers, and the like as transaction media, and performs processing such as cash deposit, payment, and remittance by user operations. The automatic cash transaction apparatus 1 includes, in an upper portion in an apparatus case: a passbook processing means (not shown) for processing a passbook of a user, printing and discharging a transaction detail; and card and receipt processing means (not shown) for processing the user's card, printing and discharging the transaction receipt.

The passbook processing means processes the passbook of the user who is inserted from the slot 2 on the front side of the automatic cash transaction apparatus 1, and prints and discharges the transaction details. The card and receipt processing means processes the card of the user who is inserted from the slot 3 on the front side of the automatic cash transaction device, prints the transaction receipt, and discharges the transaction receipt together with the card. The automatic cash transaction apparatus 1 includes a screen operation unit 4 for displaying contents of a transaction by a user and inputting various information and items for the transaction, in front of the front surface thereof.

The automatic cash transaction apparatus 1 includes a banknote handling device 10 for handling banknotes at a lower portion in a device case. The banknote deposit and withdrawal transaction is performed in accordance with the opening and closing of the shutter 5a provided in the deposit and withdrawal section 5 of the banknote handling apparatus 10.

Further, a coin handling device (not shown) for handling coins may be provided in the device case of the automatic cash transaction device 1. The coin depositing and dispensing transaction is performed in accordance with opening and closing of a shutter (not shown) provided in a depositing and dispensing section of the coin handling apparatus.

(internal Structure of automatic Cash transaction device 1)

Fig. 2 is a schematic diagram showing an internal configuration of the automatic teller machine 1 according to the embodiment. The automatic cash transaction apparatus 1 has a processing mechanism for the paper money to be transacted disposed above the lower part of the housing, and a storage mechanism for the paper money disposed below the processing mechanism. Above the lower part of the housing of the banknote handling apparatus 10, a deposit and withdrawal section 5 is disposed on the front side (the side facing the user: the upper right side in fig. 2), and the deposit and withdrawal section 5 receives deposit of banknotes placed in a substantially standing posture by the user, and places and discharges the banknotes in the substantially standing posture for the user to take out. In addition, a banknote discriminating device 30 for discriminating banknotes is disposed in the central portion, and a temporary holding section 40 is disposed in the rear side (upper left side in fig. 2), and the temporary holding section 40 temporarily stores banknotes fed by the user until the transaction is completed. The mechanism parts are connected by a bidirectional conveying path.

The banknote discriminating device 30 can discriminate the banknote conveyed on the conveyance path 30a from both the front and the rear in any direction, and can discriminate the banknote from the genuine or counterfeit. The banknote discriminating device 30 can discriminate the denomination and authenticity of the banknote transported in both directions of deposit and withdrawal, and can discriminate whether the banknote can be accepted or not and whether the banknote can be discharged or not. In the deposit and withdrawal section 5, a bill discharge section 5b for discharging bills discharged from above to below and a bill collection section 5c for collecting bills for discharge or return carried from below are arranged in the front-rear direction.

A plurality of storage units 70 for storing banknotes of a denomination are arranged below the banknote handling apparatus 10. The storage unit 70 includes a storage unit for storing banknotes that are determined to be acceptable by the banknote recognition device 30, a storage unit for temporarily storing banknotes that are determined to be unacceptable by the banknote recognition device 30, a storage unit for use in replenishing banknotes from the outside for dispensing, and the like.

(constitution of paper money discriminating device 30)

Fig. 3 is a side view showing a main part of the structure of the banknote discriminating apparatus 30 according to the embodiment. Fig. 4 is a plan view showing a main part of the structure of the banknote discriminating apparatus 30 according to the embodiment. The banknote discriminating device 30 includes various sensors such as a thickness sensor, a drive motor for the transport rollers, other transport rollers, and the like in addition to the illustrations of fig. 3 and 4, but is not illustrated.

The banknote discriminating device 30 includes a conveyance guide 30b, a discrimination sensor 31, conveyance rollers 32a and 32b, driving rollers 32a1, 32b1 and 32c1, and magnetic phase deviation alleviation plates 33a and 33b. The plurality of conveying rollers 32a are arranged in the X-axis direction on the Y-axis positive direction side of the identification sensor 31. The plurality of conveying rollers 32b are arranged in the X-axis direction on the Y-axis negative direction side of the identification sensor 31.

The conveying rollers 32a and 32b are rotated by driving rollers 32a1 and 32b1 driven by a driving motor (not shown). The banknote on the conveyance path 30a is sandwiched between conveyance rollers 32a and 32b and driving rollers 32a1 and 32b1 facing the conveyance rollers 32a and 32b, and conveyed in the positive and negative directions of the Y axis. The conveying rollers 32a and 32b are magnetized magnetic bodies such as bearing rollers, for example, and rotate around a rotation axis, whereby magnetic poles are rotated to generate a fluctuating magnetic field.

The identification sensor 31 includes a plurality of differential magnetic sensors 31a, and the plurality of differential magnetic sensors 31a include magnetic detection elements 31a1 and 31a2 arranged in the Z-axis direction. The Z-axis direction is a direction perpendicular to the surface of the banknote being transported on the transport path 30a, and is a magnetic detection direction of the differential magnetic sensor 31a (the magnetic detection elements 31a1 and 31a 2). The plurality of differential magnetic sensors 31A are arranged in an array in the X-axis direction within the identification sensor 31 to constitute a sensor array 31A. The driving roller 32c1 presses and conveys the banknote on the recognition sensor 31 with a gap therebetween to such an extent that no jam occurs.

Magnetic phase deviation alleviation plates 33a, 33b are provided between the identification sensor 31 and the conveying rollers 32a, 32b, respectively. The magnetic phase deviation alleviation plates 33a, 33b are plate-like magnetic members having a magnetic permeability of a predetermined or more, and are arranged such that their long sides extend in directions (X-axis direction, sensor array 31A direction) orthogonal to the magnetic detection directions (Z-axis direction, magnetic field detection direction) of the magnetic detection elements 31A1, 31A2.

The magnetic phase deviation alleviation plates 33a, 33b are disposed between the conveying rollers 32a, 32b and the magnetic detection elements 31a1, 31a2 at positions where magnetic fluxes reaching the magnetic detection elements 31a1, 31a2 are curved and aligned in the most uniform direction among magnetic flux paths formed by the conveying rollers 32a, 32 b. The magnetic phase deviation alleviation plates 33a and 33b are arranged in 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 conveyance rollers 32a and 32b are curved 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 alleviation plates 33a, 33b need not be disposed in the vicinity of the magnetic detection elements 31a1, 31a2. Further, by aligning the magnetic flux with a direction perpendicular to the arrangement direction of the magnetic detection elements 31a1, 31a2, the magnetic field acting on the magnetic detection elements 31a1, 31a2 can be made to detour and reduced, and even if the magnetic material (so-called magnetic shield) is not disposed in the vicinity of the magnetic detection elements 31a1, 31a2 to reduce the magnetic flux reaching the magnetic detection elements 31a1, 31a2, the phase deviation can be effectively reduced and the differential effect can be improved.

The length of the magnetic phase deviation alleviation plates 33a and 33b in the longitudinal direction (X-axis direction) is a length that can maintain the characteristics of the differential magnetic sensor 31a within a range equal to or greater than a predetermined range regardless of the dc magnetic field caused by the magnetic poles generated by the magnetic phase deviation alleviation plates 33a and 33b. The longer the magnetic phase deviation alleviation plates 33a, 33b are in the longitudinal direction (X-axis direction), the more the magnetic fluxes reaching the magnetic detection elements 31a1, 31a2 can be bent in the direction perpendicular to the arrangement direction of the magnetic detection elements 31a1, 31a2, while the longer the magnetic phase deviation alleviation plates are, the more magnetic poles are easily generated at both ends and the magnetic field thereof easily flies away, and the characteristics of the differential magnetic sensor 31a may not be maintained in the direct-current magnetic field. Therefore, the length in the longitudinal direction (X-axis direction) is selected within the range for maintaining the characteristics. The length and thickness (Y-axis direction) of the magnetic phase deviation reducing plates 33a and 33b in the short side direction (Z-axis direction) may be within a range in which the magnetic phase deviation reducing plates do not interfere with other members in the housing of the bill discriminating device 30 and in which magnetic saturation does not occur.

The magnetic phase deviation alleviation plates 33a, 33b are made of soft magnetic material having a magnetic permeability of a constant or higher selected from a group of materials including permalloy and unoriented silicon steel plates. The soft magnetic material is preferably heat-treated to reduce the coercivity so that the magnetic pole in the longitudinal direction is less likely to occur.

(functional constitution of banknote discriminating device 30)

Fig. 5 is a functional block diagram showing the structure of the banknote discriminating device 30. The banknote discriminating device 30 has, in addition to the above-described configuration, amplifiers 331 and 332 as operational amplifiers or the like, AD (analog-to-digital (Analog to Digital)) converters 341 and 342, and an arithmetic unit 35 such as a microcomputer.

The amplifier 331 amplifies the detection signal of the magnetic detection element 31a 1. 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 banknote magnetic detection values 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. Where n is a natural number starting from 0 according to the sampling number, T is a sampling period, and α1 and α2 are predetermined numbers.

As described later, the banknote magnetic detection values α1×v1 (nT) - α2×v2 (nT) in the present embodiment are obtained by performing sensitivity correction on the magnetic detection elements 31a1 and 31a2 and eliminating magnetic noise of the uniform magnetic field and the fluctuating magnetic field.

(phase difference of magnetic fluxes with respect to the magnetic detection direction)

Hereinafter, with reference to fig. 6 to 10 and fig. 11 to 15, a case will be described in which the phase difference of the magnetic fluxes in the magnetic detection directions of the magnetic detection elements 31a1 and 31a2 becomes small, with reference to the present embodiment. Fig. 6 to 10 show the case where the magnetic phase deviation alleviation plates 33a and 33b are not present (prior art), and fig. 11 to 15 show the case where the magnetic phase deviation alleviation plates 33a and 33b are present (this embodiment).

(in the case where there are no magnetic phase deviation alleviation plates 33a, 33 b)

First, a case where the magnetic phase deviation alleviation plates 33a and 33b are not provided (prior art) will be described with reference to fig. 6 to 10.

As the magnetic flux of the bill passing through the conveyance path 30a near the magnetic detection elements 31a1, 31a2, the detection value V1 (nT) of the magnetic detection element 31a1 on the upper side near the bill is larger than the detection value V2 (nT) of the magnetic detection element 31a2 on the lower side far from the bill. Thus, in general, by calculating the differences V1 (nT) -V2 (nT) of the detected values, a detection signal of the magnetic flux of the banknote passing through the conveyance path 30a in the vicinity of the magnetic detection elements 31a1, 31a2 can be obtained.

The magnetic noise sources of the uniform magnetic field are located at a position farther than the bill passing through the conveyance path 30a near the magnetic detection elements 31a1, 31a2, and thus the distances from the magnetic noise sources to the magnetic detection elements 31a1, 31a2 are substantially equal. Thus, the magnetic noise of the uniform magnetic field can be regarded as being uniformly superimposed on the detection values V1 (nT) and V2 (nT) of the magnetic detection elements 31a1 and 31a2, and thus can be eliminated by obtaining the differences V1 (nT) -V2 (nT) of the detection values.

When there is a variation in sensitivity between the upper and lower magnetic detection elements 31a1, 31a2, a uniform magnetic field is applied to the detection directions of the magnetic detection elements 31a1, 31a2, and correction coefficients α1, α2 for correcting the sensitivity are calculated in advance so that the amplitude values V1, V2 of the detection signals of the magnetic detection elements 31a1, 31a2 are the same. Then, by calculating α1×v1 (nT) - α2×v2 (nT), a detection signal in which the sensitivity is corrected and the magnetic noise is eliminated can be obtained.

Fig. 6 is a diagram for explaining a fluctuating magnetic field (in the case where the magnetic phase deviation alleviation plates 33a and 33b are not provided) in which the banknote discriminating device 30 is placed. However, as shown in fig. 6, in the case where a weakly magnetized rotating body (in fig. 6, the conveying roller 32 b) is required to be disposed in the vicinity of the differential magnetic sensor 31a in the structure of the conveying path 30a, a phase difference occurs in the magnetic fluxes reaching the upper and lower magnetic detection elements 31a1 and 31a2, and interference noise cannot be eliminated.

The reason why the magnetic fluxes reaching the upper and lower magnetic detection elements 31a1, 31a2 have a phase difference is as follows. Fig. 7 is a diagram for explaining the magnetic flux of the varying magnetic field passing through the differential magnetic sensor 31a of the bill discriminating device 30 (in the case where the magnetic phase deviation alleviation plates 33a, 33b are not present). As shown in fig. 7, the direction and magnitude of the magnetic field vector H caused by the magnetic flux passing near the sensor center Δ=0 (the center line between the magnetic detection elements 31a1 and 31a 2) between the magnetic detection elements 31a1 and 31a2 vary according to the rotation angle θ of the conveying roller 32 b. In this variation, the direction and magnitude of the magnetic field vector H are determined according to the distance from the magnetic pole S, N of the conveying roller 32 b. The closer the distance from the magnetic pole S, N is, the larger the magnetic field vector H becomes.

Fig. 8 is a diagram for explaining the component decomposition of the magnetic flux of the fluctuating magnetic field detected by the differential magnetic sensor 31a of the bill identifying device 30 (in the case where the magnetic phase deviation alleviation plates 33a, 33b are not present). However, in fig. 8, the component of the magnetic field vector H in the direction of the sensor array 31A is omitted. As shown in fig. 8, the magnetic field vector H can be decomposed into a banknote conveyance direction component vector Hy on the conveyance path 30a and a magnetic field detection direction component vector Hz of the differential magnetic sensor 31a.

The direction and magnitude of the magnetic field vector H are determined according to the distance L from the magnetic pole S, N of the conveying roller 32b (see fig. 7). The distance L periodically varies according to the rotation angle θ of the conveying roller 32b (θ is an angle formed by the magnetization direction of s→n of the conveying roller 32b and the positive Z-axis direction). Therefore, the orientations and magnitudes of the magnetic field vector H and the magnetic field detection direction component vector Hz periodically fluctuate according to the rotation angle θ of the conveying roller 32 b.

Fig. 9 is a diagram for explaining the magnetic fluxes of the varying magnetic fields passing through the 2 magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the bill discriminating device 30 (in the case where the magnetic phase deviation alleviation plates 33a and 33b are not provided). The magnetic detection element 31a1 and the magnetic detection element 31a2 are separated from each other by an inter-element distance ±Δd/2 in the magnetic field detection direction (Z-axis direction) from the sensor center Δ=0. Due to their difference in position, the magnetic field vector H1 of the magnetic detection element 31a1 and the magnetic field vector H2 of the magnetic detection element 31a2 are oriented differently from the magnetic field vector H of the center of the sensor element, respectively.

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 of the sensor center Δ=0. 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 of the sensor center Δ=0. The difference is determined by the effect of the magnetic moment of the periphery.

The magnetic field detection direction component vector H1z is periodically changed in the same manner as the magnetic field detection direction component vector Hz, but the timing of the same magnitude is later, and the magnetic field detection direction component vector H1z appears to be delayed in phase from the magnetic field detection direction component vector Hz. The magnetic field detection direction component vector H2z is periodically changed in the same manner as the magnetic field detection direction component vector Hz, but the timing at which the magnetic field detection direction component vector H2z becomes equal is earlier, and the magnetic field detection direction component vector H2z appears to be in a phase advance from the magnetic field detection direction component vector Hz.

Fig. 10 is a diagram for explaining the magnetic flux fluctuation of the fluctuating magnetic field detected by the 2 magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the bill identifying device 30 (in the case where the magnetic phase deviation alleviation plates 33a and 33b are not present). As described above, a phase difference occurs between the magnetic field detection direction component vectors H1z and H2z of the magnetic detection element 31a1 and the magnetic detection element 31a2, as shown in fig. 10, in the fluctuating magnetic field caused by the rotation of the conveying roller 32 b.

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 an external noise source generating a fluctuating magnetic field remains by an amount corresponding to the phase difference.

(in the case of the magnetic phase deviation alleviation plates 33a and 33 b)

Next, a case where the magnetic phase deviation alleviation plates 33a, 33b are provided (this embodiment) will be described with reference to fig. 11 to 15.

Fig. 11 is a diagram for explaining a fluctuating magnetic field (in the case of the magnetic phase deviation alleviation plates 33a, 33 b) in which the banknote discriminating device 30 is placed. As shown in fig. 11, in the present embodiment, a magnetic phase deviation alleviation plate 33b is provided between the differential magnetic sensor 31a and the conveying roller 32 b. In this case, the magnetic flux detected by the differential magnetic sensor 31a is attracted to the magnetic phase deviation alleviation plate 33b, and is skewed so as to be parallel to the longitudinal direction (X-axis direction) of the magnetic phase deviation alleviation plate 33b.

Fig. 12 is a diagram for explaining the magnetic flux of the varying magnetic field passing through the differential magnetic sensor 31a of the bill discriminating device 30 (in the case of the magnetic phase deviation alleviation plates 33a, 33 b). As a result, as shown in fig. 12, the magnetic field vector H' caused by the magnetic flux passing near the sensor center Δ=0 between the magnetic detection elements 31a1, 31a2 is oriented in the longitudinal direction of the magnetic phase deviation alleviation plate 33b so as to be parallel to the magnetic phase deviation alleviation plate 33b.

Fig. 13 is a diagram for explaining the component decomposition of the magnetic flux of the fluctuating magnetic field detected by the differential magnetic sensor 31a of the bill identifying device 30 (in the case of the magnetic phase deviation alleviation plates 33a, 33 b). However, in fig. 13, the component of the magnetic field vector H' in the direction of the sensor array 31A is not shown. As shown in fig. 13, the magnetic field vector H ' can be decomposed into a banknote conveyance direction component vector H ' y on the conveyance path 30a and a magnetic field detection direction component vector H ' z of the differential magnetic sensor 31a.

The orientations and magnitudes of the magnetic field vector H 'and the magnetic field detection direction component vector H' z are periodically changed according to the rotation angle θ of the conveyance roller 32b, as are the magnetic field vector H and the magnetic field detection direction component vector Hz. The magnitude |h 'z| of the magnetic field detection direction component vector H' z is smaller than the magnitude |hz| of the magnetic field detection direction component vector Hz in the case where the magnetic phase deviation alleviation plates 33a, 33b are not provided. The reason why the magnetic phase deviation reducing plates 33a and 33b attract magnetic fluxes is that the magnetic fluxes are smaller than the magnetic phase deviation reducing plates |hz|, and the magnetic fluxes decrease, or the magnetic fluxes at a distance where the magnetic fluxes have a smaller strength come close to and come onto the element.

Fig. 14 is a diagram for explaining the magnetic fluxes of the varying magnetic fields passing through the 2 magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the bill discriminating device 30 (in the case of the magnetic phase deviation alleviation plates 33a and 33 b). If the magnetic phase deviation alleviation plate 33b is provided between the differential magnetic sensor 31A and the conveying roller 32b, a force is applied to align the orientations of the magnetic fields passing through the 2 magnetic detection elements 31A1, 31A2 in agreement with the sensor array 31A direction irrespective of the position within ±Δd/2.

Therefore, for example, when the rotation angle θ=0°, the magnitude |h1' z| of the magnetic-field detection-direction component vector H1' z of the magnetic-field vector H1 of the magnetic-field detection element 31a1, the magnitude |h ' z| of the magnetic-field detection-direction component vector H ' z of the magnetic-field vector H ' of 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-field detection element 31a2 are all substantially the same. The values of |h1'z|, |hz|, |h2' z|, and |h2z|, are smaller than those of the case (prior art) where the magnetic phase deviation alleviation plates 33a and 33b are not provided. The reason why the magnetic flux is attracted by the magnetic phase deviation alleviation plates 33a and 33b is that the magnetic flux lines are reduced or the magnetic flux at a distance where the magnetic flux is originally small in strength approaches and comes onto the element is that the magnetic flux is smaller in the |h1' z|, |h2' z|, and the magnetic flux is smaller in the |h2' z| than the magnetic phase deviation alleviation plates.

As a result, the magnetic field detection direction component vectors H1' z and H2' z undergo the same periodic variation as the magnetic field detection direction component vector H ' z, and the phase difference is also substantially 0, as compared with the case where the magnetic phase deviation alleviation plates 33a and 33b are not present (conventional technique).

Fig. 15 is a diagram for explaining the magnetic flux fluctuation of the fluctuating magnetic field detected by the 2 magnetic detection elements 31a1 and 31a2 of the differential magnetic sensor 31a of the bill discriminating device 30 (in the case of the magnetic phase deviation alleviation plates 33a and 33 b). That is, as shown in fig. 15, the phase difference between the magnetic field detection direction component vectors H1'z, H2' z of the magnetic flux detected by the magnetic detection elements 31a1, 31a2 due to the conveying roller 32b is substantially 0.

As a result, magnetic noise from an external noise source that generates a fluctuating magnetic field can be eliminated from the banknote magnetic detection values α1×v1 (nT) - α2×v2 (nT) calculated in the same manner as in the conventional case, 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. That is, the banknote discriminating device 30 has the same configuration as the conventional banknote discriminating device except that the magnetic phase deviation reducing plates 33a and 33b are added.

It is found from experiments that the longer the magnetic phase deviation alleviation plates 33a and 33b are made in the sensor array 31A direction, the more the orientation of the magnetic field at ΔΣΔ+±Δd/2 between the magnetic detection elements 31A1 and 31A2 is made to coincide with the sensor array 31A direction. From this, it can be said that the longer the magnetic phase deviation alleviation plates 33a, 33b are in the sensor array 31A direction, the better the effect that external noise from an external noise source generating a fluctuating magnetic field can be reduced.

(other embodiments)

As another embodiment, a method of recognizing a sheet by the sheet recognition apparatus will be described.

The paper sheet discriminating device (for example, the banknote discriminating device 30) includes: the sheet feeder includes a magnetic noise source (e.g., conveying rollers 32a, 32b, driving rollers 32a1, 32b 1) that generates a fluctuating magnetic field, a conveying path (e.g., conveying path 30 a) that conveys a sheet (e.g., a banknote), a plurality of magnetic detection elements (e.g., magnetic detection elements 31a1, 31a 2) that are arranged in a vertical direction with respect to a surface of the sheet conveyed on the conveying path and detect magnetism of the sheet, and an arithmetic unit (e.g., arithmetic unit 35) that calculates a differential detection value based on detection signals detected by the magnetic detection elements.

In the paper sheet discriminating method of the paper sheet discriminating apparatus, a magnetic member (for example, magnetic phase deviation alleviation plates 33a and 33 b) having a magnetic permeability equal to or higher than a predetermined value and a shape extending in a width direction of a conveyance path is arranged between a plurality of magnetic detection elements and a magnetic noise source, the plurality of magnetic detection elements detect magnetism of paper sheets conveyed on the conveyance path, and an arithmetic unit calculates a differential detection value of the paper sheets conveyed on the conveyance path based on detection signals detected by the respective magnetic detection elements.

According to the above embodiment, the magnetic member having the magnetic permeability of at least a predetermined value is disposed between the plurality of magnetic detection elements and the magnetic noise source. Thus, the banknote magnetism can be detected with high accuracy by suppressing magnetic noise caused by a magnetic noise source generating a fluctuating magnetic field and improving tolerance to magnetic extraneous noise with a simple configuration without changing the method of calculating the banknote magnetism detection value α1×v1 (nT) - α2×v2 (nT). As a result, the accuracy of discriminating the authenticity of the banknote can be improved. In addition, the yield of magnetization screening of the components of the conveying mechanism can be improved.

In addition, the magnetic field of the sensor magnetic circuit is not disturbed as compared with the case where the surroundings of the element are magnetically shielded by a plate material having high magnetic permeability, and therefore, the expected characteristics can be obtained even in the case where a magnetic detection element having high sensitivity is used.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments are described in detail for the purpose of easily understanding the present invention, but are not limited to the configuration in which all the components described are necessarily provided. In addition, as long as there is no contradiction, a part of the constitution of one embodiment may be replaced with the constitution of another embodiment, or the constitution of another embodiment may be added to the constitution of one embodiment. Further, addition, deletion, substitution, integration, and division may be performed with respect to a part of the configuration of each embodiment. The processes described in the embodiments may be appropriately distributed or integrated based on the processing efficiency or the mounting efficiency.

Claims (10)

1. A paper sheet recognition device for recognizing paper sheets, comprising:

a magnetic noise source for generating a fluctuating magnetic field;

a plurality of magnetic detection elements arranged in a vertical direction with respect to a surface of a sheet being conveyed on a conveying path, for detecting magnetism of the sheet;

a magnetic member having a magnetic permeability of a predetermined or more and disposed between the plurality of magnetic detection elements and the magnetic noise source; and

and an arithmetic unit that performs a difference operation on the magnetic detection value of the sheet conveyed on the conveying path based on each detection signal detected by each of the magnetic detection elements.

2. The paper sheet discriminating apparatus as defined in claim 1, wherein,

the magnetic noise source includes: a conveying roller that rotates following the driving roller and conveys the paper sheet, and a shaft of the driving roller.

3. The paper sheet discriminating apparatus as defined in claim 1, wherein,

the magnetic member has a shape in which a long length extends in a width direction of the conveyance path.

4. The paper sheet discriminating apparatus as defined in claim 3, wherein,

the length of the long side of the magnetic member is in a range in which the magnetic detection characteristics of the plurality of magnetic detection elements can be maintained to be equal to or greater than a predetermined value regardless of the direct current magnetic field caused by the magnetic poles generated by the magnetic member.

5. The paper sheet discriminating apparatus as defined in claim 1, wherein,

the magnetic member is disposed at a position such that a path of magnetic flux passing through the plurality of magnetic detection elements is curved and aligned in correspondence with a direction perpendicular to an arrangement direction of the plurality of magnetic detection elements.

6. The paper sheet discriminating apparatus as defined in claim 5, wherein,

the magnetic member is configured to be oriented orthogonal to a magnetic field detection direction of the plurality of magnetic detection elements.

7. The paper sheet discriminating apparatus as defined in claim 1, wherein,

the magnetic member is a soft magnetic material selected from the group of materials consisting of permalloy and unoriented silicon steel plates.

8. The paper sheet discriminating apparatus as defined in claim 7, wherein,

the soft magnetic material is heat treated.

9. A sheet handling apparatus comprising the sheet identifying apparatus according to any one of claims 1 to 8.

10. A paper sheet identifying method for identifying paper sheets is characterized in that,

in a paper sheet discriminating device having a magnetic noise source generating a fluctuating magnetic field, a plurality of magnetic detection elements arranged in a direction perpendicular to a surface of a paper sheet being conveyed on a conveying path and detecting magnetism of the paper sheet, and an arithmetic unit for calculating a differential detection value of the paper sheet being conveyed on the conveying path based on detection signals detected by the magnetic detection elements,

a magnetic member having a magnetic permeability equal to or higher than a predetermined value and having a shape with a long side extending in a width direction of the conveyance path perpendicular to a magnetic field detection direction of the plurality of magnetic detection elements is disposed between the plurality of magnetic detection elements and the magnetic noise source,

the plurality of magnetic detection elements detect magnetism of the paper sheets conveyed on the conveying path,

the arithmetic unit performs a difference operation on the magnetic detection value of the sheet conveyed on the conveying path based on each detection signal detected by each of the magnetic detection elements.

Images