Paper handling device and foreign object detection method

Abstract

A paper sheet handling device comprising: a conveyance path on which a bundle (2A) of paper sheets is conveyed; and a detection unit (7) which has a plurality of ultrasonic sensors (21-1, 21-2, 21-3) disposed on the conveyance path and which uses the plurality of ultrasonic sensors (21-1, 21-2, 21-3) to detect the presence or absence of foreign matter (3) that has been mixed into the bundle (2A) of paper sheets. The detection unit (7) emits ultrasonic waves from the plurality of ultrasonic sensors (21-1, 21-2, 21-3) toward a plurality of positions (P1, P2, P3), respectively, on the paper surface (2s) of the bundle (2A) of paper sheets conveyed along the conveyance path and detects the presence or absence of the foreign matter (3) on the basis of reflected waves of the ultrasonic waves from the plurality of positions (P1, P2, P3).

Description

[Technical Field]

[0001] The present invention relates to a paper sheet handling device and a foreign object detection method. [Background technology]

[0002] Known examples of paper handling devices include banknote handling devices such as automated teller machines, etc. This type of banknote handling device is known to include a detection unit that detects the presence or absence of foreign objects, such as banknote clips used to bundle banknotes together or coins, which may be mixed in with deposited banknotes.

[0003] Such a detection unit may, for example, have a metal sensor that detects foreign matter based on the amount of metal mixed in the banknote. However, when handling banknotes that have been subjected to magnetic printing or the like and have a high metal content, the metal sensor may erroneously detect the presence of foreign matter in banknotes that do not contain any foreign matter. Furthermore, in a banknote handling device, the metal sensor may erroneously detect a metal plate or the like that is present around the location where the metal sensor is installed as a foreign matter. Furthermore, instead of a metal sensor, some detection units use an ultrasonic sensor to irradiate ultrasonic waves onto the banknote and detect the presence or absence of foreign matter based on the amount of transmitted waves (sound wave volume) of the ultrasonic waves that pass through the banknote. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-189497 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-351141 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the detection unit with an ultrasonic sensor uses the amount of transmitted ultrasonic waves that pass through one banknote as a reference value, and detects the presence of a foreign object when the amount of transmitted ultrasonic waves becomes smaller than this reference value. Because detection is based on the amount of transmitted ultrasonic waves, when handling a bundle of multiple banknotes, it becomes difficult to detect a foreign object as the amount of transmitted waves that pass through the bundle of multiple banknotes decreases. Therefore, there is a problem in that the accuracy of detecting the presence or absence of a foreign object mixed in the bundle of banknotes is low.

[0006] The disclosed technology has been developed in consideration of the above, and aims to provide a paper handling device and a foreign object detection method that can improve the accuracy of detecting whether or not foreign objects have been mixed into a stack of paper sheets. [Means for solving the problem]

[0007] One aspect of the paper sheet handling device disclosed in the present application comprises a transport path along which a stack of paper sheets is transported, and a detection unit having a plurality of ultrasonic sensors arranged on the transport path and detecting the presence or absence of foreign matter mixed into the stack of paper sheets using the plurality of ultrasonic sensors, wherein the detection unit irradiates ultrasonic waves from the plurality of ultrasonic sensors toward a plurality of positions on the surface of the stack of paper sheets transported along the transport path, and detects the presence or absence of the foreign matter based on the reflected waves of the ultrasonic waves from the plurality of positions. [Effects of the Invention]

[0008] According to one aspect of the paper sheet handling device disclosed in the present application, it is possible to improve the accuracy of detecting whether or not a foreign object has been mixed into a stack of paper sheets. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a typical banknote handling machine according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic view of the banknote handling machine of the embodiment. [Figure 3] FIG. 3 is a vertical cross-sectional view for explaining the operation of the transport mechanism in the embodiment. [Figure 4]FIG. 4 is a plan view schematically showing a detection unit in the embodiment. [Figure 5] FIG. 5 is a schematic diagram for explaining the principle of detecting foreign matter in the embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining the principle of detecting foreign matter in the embodiment. [Figure 7] FIG. 7 is a flowchart for explaining the foreign object detection operation in the banknote handling machine of the embodiment. [Figure 8] FIG. 8 is a schematic diagram for explaining a state in which detection of the presence or absence of foreign matter is repeated multiple times at regular intervals in the conveying direction of the conveying path in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the paper handling device and foreign object detection method disclosed herein will be described in detail with reference to the accompanying drawings. Note that the paper handling device and foreign object detection method disclosed herein are not limited to the following embodiments. [Example]

[0011] (Configuration of banknote handling device) Fig. 1 is a longitudinal sectional view schematically showing a bill handling machine of an embodiment, and Fig. 2 is a transverse sectional view schematically showing the bill handling machine of an embodiment.

[0012] 1 and 2, a banknote handling apparatus 1 of the embodiment includes an insertion slot (deposit slot) 4 into which a banknote bundle 2A to be deposited is inserted, a transport path 5 along which the deposited banknote bundle 2A is transported, a transport mechanism 6 that transports the banknote bundle 2A along the transport path 5, a detection unit 7 that detects the presence or absence of foreign matter 3 mixed in the banknote bundle 2A using a plurality of ultrasonic sensors, and a pressing unit 8 that presses the banknote bundle 2A transported along the transport path 5 in the thickness direction of the banknote bundle 2A. The banknote handling apparatus 1 also includes a storage unit 9 that stores the banknote bundle 2A transported by the transport mechanism 6, a discrimination unit 10 that discriminates the authenticity of banknotes 2 sent from the storage unit 9, and a control unit 11 that controls each of the units 5 to 10.

[0013] For ease of explanation, in Fig. 1, when viewed from the front side of the banknote handling apparatus 1 where the insertion slot 4 is located, the width direction of the banknote handling apparatus 1 will be referred to as the X direction, the front-to-rear direction of the banknote handling apparatus 1 as the Y direction, and the up-to-down direction of the banknote handling apparatus 1 as the Z direction. In the drawings subsequent to Fig. 1, the X, Y, and Z directions will be indicated as in Fig. 1. In this embodiment, banknotes 2 are used as an example of paper sheets, but the paper sheets are not limited to banknotes 2. Paper sheets also include, for example, negotiable instruments such as bills, checks, gift certificates, various securities, and stock certificates.

[0014] Furthermore, in this embodiment, the banknote bundle 2A refers to a bundle of, for example, about 100 to 200 banknotes 2 stacked on top of each other, but the number of banknotes 2 in the banknote bundle 2A is not limited to this. The banknote bundle 2A in this embodiment includes, for example, a bundle of two banknotes 2 stacked on top of each other. The foreign objects 3 that the detection unit 7 detects are not limited to coins, paperclips, etc. present inside the banknote bundle 2A, but also include coins placed on the paper surface 2s of the banknote bundle 2A and paperclips, etc. located on the paper surface 2s of the banknote bundle 2A.

[0015] (Transport path) The bill bundle 2A is inserted into the insertion slot 4 along the short side of the rectangular bills 2. The transport path 5 is provided along the insertion direction (Y direction) of the bill bundle 2A into the insertion slot 4. Therefore, the bill bundle 2A is transported through the transport path 5 along the short side of the bills 2.

[0016] (Transport mechanism) Fig. 3 is a vertical cross-sectional view for explaining the operation of the conveying mechanism 6 in this embodiment. As shown in Fig. 2 and Fig. 3, the conveying mechanism 6 has a shuttle 13 that reciprocates along the conveying path 5, a transfer belt 14 that moves the bank-note bundle 2A relative to the shuttle 13, and a conveying belt 15 that conveys the shuttle 13 along the conveying path 5. The conveying mechanism 6 also has a gear 16a and a motor 16b that raise and lower an upper shuttle member 13A (described later) that is included in the shuttle 13, a gear 17a and a motor 17b that drive the transfer belt 14, and a gear 18a and a motor 18b that drive the conveying belt 15.

[0017] The shuttle 13 has an upper shuttle member 13A and a lower shuttle member 13B as a pair of transport members that sandwich and transport the banknote bundle 2A in the thickness direction (Z direction) of the banknote bundle 2A. The lower shuttle member 13B has a placement surface 20 on which the banknote bundle 2A inserted through the insertion slot 4 is placed. The upper shuttle member 13A is provided so as to be able to move up and down in the Z direction so as to sandwich the banknote bundle 2A between itself and the placement surface 20 of the lower shuttle member 13B. The shuttle 13 is provided with an insertion sensor (not shown) that detects the insertion of the banknote bundle 2A into the shuttle 13, and when the insertion of the banknote bundle 2A through the insertion slot 4 is detected, the transport mechanism 6 lowers the upper shuttle member 13A towards the lower shuttle member 13B.

[0018] When the banknote bundle 2A is inserted into the lower shuttle member 13B through the insertion slot 4, the upper shuttle member 13A is lowered by the gear 16a and the motor 16b, thereby sandwiching the banknote bundle 2A between itself and the lower shuttle member 13B. As a result, the transport mechanism 6 transports the banknote bundle 2A sandwiched between the upper shuttle member 13A and the lower shuttle member 13B in the thickness direction (Z direction) of the banknote bundle 2A. The upper shuttle member 13A is formed in a shape that does not block ultrasonic waves irradiated from the detection unit 7 toward the paper surface 2s of the banknote bundle 2A.

[0019] The transfer belt 14 is provided on the upper shuttle member 13A and the lower shuttle member 13B so as to move in the conveying direction (Y direction) along the lower surface 19 of the upper shuttle member 13A and the placement surface 20 of the lower shuttle member 13B. The transfer belt 14 moves the banknote bundle 2A placed on the placement surface 20 so as to pull it toward the back side (storage unit 9 side) within the shuttle 13. After the shuttle 13 has been transported to the storage unit 9, the transfer belt 14 moves the banknote bundle 2A in the shuttle 13 into the interior of the storage unit 9.

[0020] Conveyor belts 15 are arranged along the conveying direction (Y direction) on both sides of the width direction (X direction) of conveying path 5, and support lower shuttle members 13B of shuttle 13 via gears 18a. The conveying mechanism 6 conveys the bill bundle 2A inserted from insertion slot 4 along conveying path 5 to storage unit 9 by sending shuttle 13 on which bill bundle 2A is placed by conveyor belts 15.

[0021] The shuttle 13 is also provided with a pressing section 8, and the pressing section 8 has a plurality of rollers 25 (described later) that are arranged on the upper shuttle member 13A and the lower shuttle member 13B.

[0022] (Detection unit) Fig. 4 is a plan view schematically showing the detection unit 7 in this embodiment. As shown in Fig. 4, the detection unit 7 in this embodiment has, as an example, a first ultrasonic sensor 21-1, a second ultrasonic sensor 21-2, and a third ultrasonic sensor 21-3 (hereinafter also referred to as each ultrasonic sensor 21), and is electrically connected to the control unit 11. Although not shown, each ultrasonic sensor 21 has a transmitter that emits ultrasonic waves toward the paper surface 2s of the banknote bundle 2A, and a receiver that receives reflected waves of the ultrasonic waves from the paper surface 2s of the banknote bundle 2A, and sends a detection signal to the control unit 11 when the receiver detects the reflected waves.

[0023] In this embodiment, the control unit 11 is a control circuit on a control board provided inside the banknote handling apparatus 1, but is not limited to this and an external computer connected to the banknote handling apparatus 1 may also be used.

[0024] The detection unit 7 emits ultrasonic waves from multiple ultrasonic sensors 21 (e.g., first ultrasonic sensor 21-1, second ultrasonic sensor 21-2, third ultrasonic sensor 21-3) toward multiple positions (e.g., first position P1, second position P2, third position P3) on the paper surface 2s of the banknote bundle 2A transported along the transport path 5 (see Figures 5 and 6), and detects the presence or absence of a foreign object 3 based on the reflected waves of the ultrasonic waves from the multiple positions.

[0025] In the embodiment, the control unit 11 determines whether or not a foreign object 3 is present based on the detection signals from each ultrasonic sensor 21, and the detection unit 7 detecting whether or not a foreign object 3 is present is defined as each ultrasonic sensor 21 of the detection unit 7 sending a detection signal to the control unit 11. The detection unit 7 may also include a calculation processing unit that determines whether or not a foreign object 3 is present based on the detection signals from each ultrasonic sensor 21, independent of the control unit 11. The paper surface 2s of the banknote bundle 2A refers to the surface of the banknote 2 facing each ultrasonic sensor 21, and for example refers to the printed surface of the banknote 2 arranged on the top of the banknote bundle 2A.

[0026] The ultrasonic sensors 21 are arranged at intervals in the width direction (X direction) of the conveyance path 5, which is perpendicular to the conveyance direction (Y direction), on a plane (XY plane) perpendicular to the thickness direction (Z direction) of the banknote bundle 2A conveyed along the conveyance path 5. In other words, the ultrasonic sensors 21 are arranged at intervals in the long side direction (X direction) of the banknotes 2 in the banknote bundle 2A conveyed along the conveyance path 5. The interval between the ultrasonic sensors 21 is set to, for example, approximately the average diameter of multiple types of coins that are considered to be foreign objects 3. The ultrasonic sensors 21 are supported by, for example, a structure such as a top plate of the banknote handling device 1 that faces the conveyance path 5.

[0027] In this embodiment, the ultrasonic sensors 21 are arranged at intervals in the width direction (X direction) of the conveyance path 5, but the arrangement is not limited to this. The ultrasonic sensors 21 may also be arranged at intervals in the conveyance direction (Y direction) of the banknote bundle 2A, as shown in FIG. 4, for example. Furthermore, the ultrasonic sensors 21 may be arranged in a grid pattern on a plane (XY plane) perpendicular to the thickness direction (Z direction) of the banknote bundle 2A conveyed along the conveyance path 5, that is, arranged at equal intervals in the conveyance direction (Y direction) and width direction (X direction) of the conveyance path 5. Arranging the ultrasonic sensors 21 in a grid pattern improves the detection accuracy of the foreign object 3 and enables the foreign object 3 to be detected quickly within a predetermined range on the paper surface 2s of the banknote bundle 2.

[0028] As will be described in detail later, each ultrasonic sensor 21 is set to irradiate ultrasonic waves with a frequency of 3.4 MHz or higher onto the paper surface 2s of the banknote bundle 2A. This enables the detection unit 7 to detect the amount of change (swelling amount) of the paper surface 2s caused by the foreign object 3, or whether the amount of change due to the swelling of the foreign object 3 on the paper surface 2s is 1.0 mm or more, for example, with a detection accuracy of 0.1 mm or lower. Based on the detection result of the detection unit 7, the control unit 11 determines whether a foreign object 3 is not present in the banknote bundle 2A (no foreign object) or whether a foreign object 3 is present in the banknote bundle 2A (foreign object present).

[0029] The detection unit 7 also has a position sensor 23 that detects the banknote bundle 2A transported by the transport mechanism 6 to the position of each ultrasonic sensor 21. The position sensor 23 is disposed near one of the first ultrasonic sensor 21-1, the second ultrasonic sensor 21-2, and the third ultrasonic sensor 21-3, and is electrically connected to the control unit 11. For example, a reflective optical sensor or a transmissive optical sensor is used as the position sensor 23. The position sensor 23 detects that the banknote bundle 2A has reached the position of each ultrasonic sensor 21 when the detection light emitted by the position sensor 23 is blocked, for example, by the banknote bundle 2A or the shuttle 13, and transmits a detection signal to the control unit 11. Based on this detection signal, the control unit 11 causes the detection unit 7 to start detection.

[0030] Therefore, the detection unit 7 starts detecting whether or not there is a foreign object 3 in the banknote bundle 2A after detecting that the banknote bundle 2A has arrived at the position of each ultrasonic sensor 21. When the detection unit 7 detects whether or not there is a foreign object 3, the detection is performed while the banknote bundle 2A is being transported by the transport mechanism 6, but the detection may also be performed by temporarily stopping the transport of the banknote bundle 2A.

[0031] Furthermore, as will be described in more detail later, the detection unit 7 detects the presence or absence of a foreign object 3, that is, by irradiating ultrasonic waves from each ultrasonic sensor 21 onto the paper surface 2s of the banknote bundle 2A and receiving reflected waves of the ultrasonic waves from the paper surface 2s, and repeats this detection intermittently multiple times at regular intervals in the conveying direction (Y direction) of the conveying path 5 relative to the paper surface 2s of the banknote bundle 2A.

[0032] (Pressing part) 2, pressing unit 8 has a plurality of rollers 25 that presses banknote bundle 2A being transported along transport path 5 in the thickness direction (Z direction) of banknote bundle 2A. The plurality of rollers 25 are provided on opposing surfaces of upper shuttle member 13A and lower shuttle member 13B that face each other, i.e., on the lower surface 19 of upper shuttle member 13A and the loading surface 20 of lower shuttle member 13B. In other words, the plurality of rollers 25 are arranged on both sides of the thickness direction (Z direction) of banknote bundle 2A placed on shuttle 13, i.e., on both sides of transport path 5 in the up-down direction (Z direction).

[0033] By pressing the bill bundle 2A from both sides in the thickness direction (Z direction) using multiple rollers 25 arranged in this manner, bulging of the paper surface 2s caused by wrinkles or folds in the bill bundle 2A is suppressed, and changes in the paper surface 2s caused by such bulging are avoided, making it possible to properly detect bulging caused by foreign matter 3 and improving the accuracy of detecting foreign matter 3.

[0034] In addition, by arranging the multiple rollers 25 on both sides of the thickness direction (Z direction) of the banknote bundle 2A, the effect of pressing the banknote bundle 2A in the thickness direction (Z direction) can be enhanced, but this is not limited to this and the rollers 25 may be arranged on only one side of the thickness direction (Z direction) of the banknote bundle 2A.

[0035] The rollers 25 are arranged in a grid pattern on a plane (XY plane) perpendicular to the thickness direction (Z direction) of the banknote bundle 2A transported along the transport path 5. In the embodiment, as an example, a total of nine rollers 25 are arranged at intervals in the transport direction (Y direction) of the transport path 5 and in the width direction (X direction) of the transport path 5.

[0036] The banknote bundle 2A inserted into the shuttle 13 from the insertion slot 4 is sandwiched between the upper shuttle member 13A and the lower shuttle member 13B, and then sent along the conveying direction (Y direction) by the transfer belt 14, thereby moving the banknote bundle 2A from the insertion slot 4 side to the storage section 9 side within the shuttle 13. When the banknote bundle 2A is moved within the shuttle 13 in this way, the banknote bundle 2A is pressed in its thickness direction (Z direction) by the multiple rollers 25, thereby suppressing the bulging of the paper surface 2s described above. Therefore, in the conveying mechanism 6, the transfer belt 14 provided on the lower shuttle member 13B corresponds to a moving member that moves the banknote bundle 2A sandwiched between the pair of upper and lower shuttle members 13A and 13B relative to the multiple rollers 25.

[0037] (Storage section) 1, 2, and 3, the storage unit 9 has a stage 26 on which the banknote bundle 2A received from the shuttle 13 of the transport mechanism 6 is placed, a pusher member 27 that presses the banknote bundle 2A on the stage 26, an elevator mechanism (not shown) that raises and lowers the stage 26 and the pusher member 27 in the Z direction, and a feed-out mechanism 28 that sends the banknotes 2 of the banknote bundle 2A on the stage 26 to the validation unit 10. The feed-out mechanism 28 has a pickup roller 28a that feeds the banknotes 2 from the banknote bundle 2A on the stage 26, a separation roller 28b that separates the banknotes 2 of the banknote bundle 2A one by one, and gears and motors (not shown) that drive the rollers 28a, 28b.

[0038] In the storage unit 9, after the banknote bundle 2A sent by the transport mechanism 6 is placed on the stage 26, the stage 26 is lowered together with the pusher member 27, and the payout mechanism 28 sends the banknotes 2 one by one from the banknote bundle 2A on the stage 26 to the validation unit 10. The banknotes 2 sent one by one from the storage unit 9 in this way are validated by the validation unit 10.

[0039] (Detection principle of foreign objects in a stack of banknotes) 5 and 6 are schematic diagrams for explaining the principle of detecting a foreign object 3 in the embodiment. Fig. 5 shows a case where there is no foreign object in the bill bundle 2A, and Fig. 6 shows a case where there is a foreign object in the bill bundle 2A.

[0040] As shown in FIGS. 5 and 6, the control unit 11 measures, by means of the detection unit 7, a first distance L1 between the first ultrasonic sensor 21-1 and a first position P1 on the paper surface 2s of the banknote bundle 2A, a second distance L2 between the second ultrasonic sensor 21-2 and a second position P2 on the paper surface 2s of the banknote bundle 2A, and a third distance L3 between the third ultrasonic sensor 21-3 and a third position P3 on the paper surface 2s of the banknote bundle 2A, respectively.

[0041] Each of the distances L1, L2, and L3 is calculated by measuring the elapsed time from when the transmitter of the ultrasonic sensor 21 emits ultrasonic waves until the receiver receives the reflected wave of the ultrasonic waves from the paper surface 2s of the banknote bundle 2A. Here, when the distance between each ultrasonic sensor 21 and the paper surface 2s of the banknote bundle 2A is L [mm], the round-trip time for the ultrasonic waves to travel the distance L is T [s], and the propagation speed in air is V [m / s], it is obtained by L = V × T × (1 / 2).

[0042] Subsequently, the control unit 11 calculates, respectively, distance differences |S1|, |S2|, and |S3|, which are the absolute values of the differences between the distances L1, L2, and L3 of the respective ultrasonic sensors 21 described above. |S1| = |(L1 - L2)| |S2| = |(L1 - L3)| |S3| = |(L2 - L3)|

[0043] Then, the control unit 11 compares the distance differences |S1|, |S2|, and |S3| with a threshold G, for example, 1.0 [mm], for determining the presence or absence of the foreign object 3. If any of the distance differences |S1|, |S2|, and |S3| is greater than or equal to the threshold G (|S| ≥ G), it is determined that there is a foreign object. On the other hand, if any of the distance differences |S1|, |S2|, and |S3| is less than the threshold G (|S| < G), the control unit 11 determines that there is no foreign object.

[0044] As shown in FIG. 5, in the case where there is no foreign object, the paper surface 2s of the banknote bundle 2A becomes flat without any change due to the swelling, and the first distance L1, the second distance L2, and the third distance L3 between each ultrasonic sensor 21 and the paper surface 2s of the banknote bundle 2A are equal to each other. Therefore, each distance difference |S1|, |S2|, |S3| becomes "0", and the control unit 11 determines that there is no foreign object.

[0045] As an example, as shown in FIG. 6, when a foreign object 3 is located near the center of the paper surface 2s of the banknote bundle 2A and there is a foreign object, a change due to the swelling of the paper surface 2s occurs at the second position P2 corresponding to the second ultrasonic sensor 21-2. Therefore, the second distance L2 between the second ultrasonic sensor 21-2 and the second position P2 of the paper surface 2s of the banknote bundle 2A is smaller than the first distance L1 between the first ultrasonic sensor 21-1 and the first position P1 of the paper surface 2s of the banknote bundle 2A, and the third distance L3 between the third ultrasonic sensor 21-3 and the third position P3 of the paper surface 2s of the banknote bundle 2A (L2 < L1, L2 < L3), and the first distance L1 and the third distance L3 are equal (L1 = L3). At this time, when the distance difference |S1| between the second distance L2 and the first distance L1 and the distance difference |S3| between the second distance L2 and the third distance L3 are equal to or greater than the threshold value G, the control unit 11 determines that there is a foreign object.

[0046] (Frequency of ultrasonic wave) The frequency of the ultrasonic wave emitted by the transmitter of each ultrasonic sensor 21 is set so that the resolution for detecting the change amount of the paper surface 2s of the banknote bundle 2A due to the foreign object 3, that is, the distance L between the paper surface 2s of the banknote bundle 2A and the ultrasonic sensor 21, is 0.1 [mm] or less. When the wavelength of the ultrasonic wave is λ, the propagation speed in the air is V, and the frequency of the ultrasonic wave is f, it is expressed by λ = (V / f), and the frequency f of the ultrasonic wave is obtained by f = (V / λ).

[0047] Since the resolution function of the distance L, which is the change amount of the paper surface 2s of the banknote bundle 2A, is determined by the wavelength of the ultrasonic wave, when λ = 0.1 [mm] and V = 340 [m / s], the frequency f of the ultrasonic wave is f = (V / λ) = { (340 [m / s] × 10 3 ) / 0.1 [mm]} / 10 6 = 3.40 [MHz].

[0048] Therefore, by using each ultrasonic sensor 21 to irradiate ultrasonic waves with a frequency f of 3.4 MHz or more onto the paper surface 2s of the banknote bundle 2A, the detection unit 7 is able to detect changes of 0.1 mm or less in the paper surface 2s caused by the swelling due to the foreign object 3, thereby ensuring appropriate resolution for detecting foreign objects 3 such as coins.

[0049] Based on the detection results of each ultrasonic sensor 21, the control unit 11 determines that a foreign object is present when any of the distance differences |S1|, |S2|, and |S3| is 1.0 mm or greater. The threshold value G for determining the presence or absence of a foreign object 3 is set to 1.0 mm or greater, for example, based on the fact that the thickness of coins used in Japan is approximately 1.5 mm to 1.8 mm and the dimensions of a typical paper clip, but is not limited to this. The threshold value G is set appropriately based on the thickness of coins and the like used in the environment in which the banknote handling device 1 is installed.

[0050] (Foreign object detection operation in banknote handling equipment) FIG. 7 is a flowchart for explaining the operation of detecting a foreign object 3 in the banknote handling apparatus 1 of the embodiment.

[0051] In the banknote handling device 1, when a banknote bundle 2A inserted through the insertion slot 4 is pulled into the shuttle 13 by the transport belt 14, the banknote bundle 2A is sandwiched between the upper shuttle member 13A and the lower shuttle member 13B and pressed in the thickness direction (Z direction) of the banknote bundle 2A by the plurality of rollers 25. This prevents the banknote bundle 2A placed in the shuttle 13 from swelling of the paper surface 2s due to wrinkles or folds in the banknotes 2 of the banknote bundle 2A, and the banknote bundle 2A is sent to the detection unit 7 by the transport mechanism 6, as shown in Figures 1 and 2.

[0052] 7, the banknote handling apparatus 1 detects the banknote bundle 2A transported by the transport mechanism 6 using the position sensor 23 of the detection unit 7, and determines whether the banknote bundle 2A has arrived at the detection unit 7 using the control unit 11 (step S1). If the banknote bundle 2A has not arrived at the detection unit 7 (NO) in step S1, the banknote handling apparatus 1 continues to detect the banknote bundle 2A using the position sensor 23. If the banknote bundle 2A has arrived at the detection unit 7 (YES) in step S1, the banknote handling apparatus 1 starts detecting the presence or absence of a foreign object 3 using the detection unit 7 (step S2), irradiates ultrasonic waves onto the paper surface 2s of the banknote bundle 2A using each ultrasonic sensor 21, and starts measuring the round-trip time T until each ultrasonic sensor 21 receives the reflected wave from the paper surface 2s (step S3).

[0053] Next, the banknote handling device 1 determines, by the control unit 11, whether or not the reflected wave of the ultrasonic wave reflected by the paper surface 2s of the banknote bundle 2A has been detected by each ultrasonic sensor 21 (step S4). If the reflected wave is not detected by the ultrasonic sensor 21 (NO) in step S4, the ultrasonic sensor 21 continues to detect the reflected wave. If the reflected wave is detected by the ultrasonic sensor 21 (YES) in step S4, measurement of the round-trip time T is stopped at the point when the reflected wave is received (step S5).

[0054] Next, the banknote handling machine 1 causes the control unit 11 to calculate the round-trip time T of the ultrasonic waves for each ultrasonic sensor 21 based on the detection results from each ultrasonic sensor 21 (step S6). The control unit 11 uses the round-trip time T to calculate the distance L (L1, L2, L3) for each ultrasonic sensor 21 (step S7), and uses the distance L to calculate the distance difference |S| (|S1|, |S2|, |S3|) (step S8).

[0055] Next, the banknote handling apparatus 1 determines whether the distance difference |S| (|S1|, |S2|, |S3|) of each ultrasonic sensor 21 is 1.0 mm or more (|S|≧1.0 mm) using the control unit 11 (step S9). If the distance difference |S| is 1.0 mm or more (YES) in step S9, the control unit 11 determines that a foreign object has been mixed into the banknote bundle 2A (step S10), and returns the banknote bundle 2A to the user by returning the banknote bundle 2A to the insertion slot 4 using the transport mechanism 6 (step S11). This causes the banknote handling apparatus 1 to finish detecting the foreign object 3 (step S15).

[0056] If the distance difference |S| is less than 1.0 mm (NO) in step S9, the control unit 11 determines that no foreign matter has been mixed into the banknote bundle 2A (step S12), and waits for a fixed time for the detection unit 7 to detect the presence or absence of the foreign matter 3 (step S13). By waiting for the fixed time in step S13, the banknote handling device 1 causes the transport mechanism 6 to transport the banknote bundle 2A a fixed transport distance.

[0057] Next, the banknote handling apparatus 1 determines, via the control unit 11, whether the banknote bundle 2A is detected by the position sensor 23, in other words, whether the banknote bundle 2A has passed through the detection unit 7 (step S14). If the banknote bundle 2A has passed through the detection unit 7 in step S14 (YES), the banknote handling apparatus 1 ends detection of the foreign object 3 (step S15). On the other hand, if the banknote bundle 2A has not passed through the detection unit 7 in step S14 (NO), the banknote handling apparatus 1 returns to step S2 again and continues detecting the presence or absence of the foreign object 3.

[0058] Here, the waiting time for a certain period of time in step S13 will be described. Fig. 8 is a schematic diagram for explaining a state in which detection of the presence or absence of foreign matter 3 is repeated multiple times at regular intervals in the conveying direction (Y direction) of the conveying path 5 in this embodiment.

[0059] In this embodiment, as shown in Fig. 8, when the foreign object 3 is a coin and ultrasonic waves are applied to position P1-1 to detect that the foreign object 3 is not present at position P1-1, the foreign object 3 is treated as not being present for a certain transport distance from position P1-1 along the transport direction (Y) that corresponds to the diameter of the coin. After performing detection at position P1-1, the detection unit 7 waits to perform detection while the banknote bundle 2A moves the certain transport distance, and then performs detection at the next position P1-2 after the banknote bundle 2A has been transported by the diameter of the coin. Similarly, after performing detection at position P1-2, the detection unit 7 waits to perform detection while the banknote bundle 2A moves the certain transport distance, and then performs detection at the next position P1-3 after the banknote bundle 2A has been transported by the diameter of the coin.

[0060] In this case, the detection waiting time is, for example, when the diameter of the coin is 30 [mm] and the conveying speed of the bill bundle 2A is 1600 [mm / s], the conveying time X for conveying the bill bundle 2A by a certain conveying distance corresponding to the diameter of the coin is X = 30 [mm] / (1600 [mm / s] × 10 3 )=18.8[ms].

[0061] Therefore, the detection unit 7 intermittently repeats detection every time the banknote bundle 2A is fed by 18.8 [mm]. The detection timing of the detection unit 7 is controlled by the control unit 11 based on the conveying speed of the conveying mechanism 6.

[0062] This enables the detector 7 to detect foreign objects 3 throughout the entire transport direction (Y direction) of the banknote bundle 2A, while minimizing the number of times the detector performs detection. As a result, the banknote handling device 1 can reduce the detection time required to detect foreign objects 3 throughout the entire transport direction (Y direction) of the banknote bundle 2A, and perform detection while the transport mechanism 6 is transporting the banknote bundle 2A.

[0063] (Foreign object detection method) A foreign object detection method for detecting a foreign object 3 mixed in a banknote bundle 2A in the banknote handling apparatus 1 of the embodiment configured as described above will be described. The foreign object detection method of the embodiment includes conveying the banknote bundle 2A along the conveyance path 5, irradiating ultrasonic waves from a plurality of ultrasonic sensors 21 arranged on the conveyance path 5 toward a plurality of positions (e.g., a first position P1, a second position P2, a third position P3) on the paper surface 2s of the banknote bundle 2A conveyed along the conveyance path 5, and detecting the presence or absence of a foreign object 3 mixed in the banknote bundle 2A based on the reflected waves of the ultrasonic waves from the plurality of positions. Note that while the foreign object detection method of the embodiment is performed by the banknote handling apparatus 1, it may also be applied to a program that causes a computer to execute detection in the foreign object detection method and control the conveyance of the banknote bundle 2A, or to a recording medium such as an optical disk on which this program is recorded.

[0064] (Effects of the Example) As described above, the banknote handling device 1 of the embodiment includes the transport path 5 along which the banknote bundle 2A is transported, and the detection unit 7 that detects the presence or absence of a foreign object 3 mixed in the banknote bundle 2A using multiple ultrasonic sensors 21 arranged on the transport path 5. The detection unit 7 irradiates ultrasonic waves from the multiple ultrasonic sensors 21 toward multiple positions (e.g., first position P1, second position P2, third position P3) on the paper surface 2s of the banknote bundle 2A transported along the transport path 5, and detects the presence or absence of a foreign object 3 based on the reflected waves of the ultrasonic waves from the multiple positions. This makes it possible to properly detect the presence or absence of a foreign object 3 regardless of the number of banknotes in the banknote bundle 2A, thereby improving the detection accuracy of the presence or absence of a foreign object 3 mixed in the banknote bundle 2A. In other words, the detection unit 7 of the embodiment can achieve improved detection accuracy, for example, when detecting the presence or absence of a foreign object 3 mixed in a banknote bundle 2A that has been subjected to magnetic printing or the like, compared to a magnetic sensor or an ultrasonic sensor that uses transmitted ultrasonic waves.

[0065] Furthermore, the detection unit 7 of the banknote handling device 1 of the embodiment repeatedly detects the presence or absence of foreign matter 3 multiple times at regular intervals in the conveying direction (Y direction) of the conveyance path 5 relative to the paper surface 2s of the banknote bundle 2A. This makes it possible to detect the presence or absence of foreign matter 3 over the entire conveying direction (Y direction) of the paper surface 2s of the banknote bundle 2A, and reduces the number of detections so that detection is performed at an appropriate frequency. As a result, the detection time required to detect foreign matter 3 over the entire conveying direction (Y direction) of the banknote bundle 2A is shortened, and it becomes possible to perform detection while the banknote bundle 2A is being conveyed by the conveyance mechanism 6.

[0066] The banknote handling device 1 of the embodiment also includes a pressing unit 8 having a plurality of rollers 25 that press the banknote bundle 2A transported along the transport path 5 in the thickness direction (Z direction) of the banknote bundle 2A. This suppresses bulging of the paper surface 2s caused by wrinkles or creases in the banknotes 2 of the banknote bundle 2A sent to the detection unit 7, making it possible to properly detect bulging caused by foreign matter 3, thereby improving the detection accuracy of foreign matter 3.

[0067] Furthermore, the multiple rollers 25 of the pressing unit 8 in the banknote handling device 1 of the embodiment are arranged in a grid pattern on a plane (XY plane) perpendicular to the thickness direction (Z direction) of the banknote bundle 2A transported along the transport path 5. As a result, the multiple rollers 25 further suppress bulging of the paper surface 2s caused by wrinkles or creases in the banknotes 2 of the banknote bundle 2A sent to the detection unit 7, making it possible to more accurately detect bulging due to foreign matter 3, thereby further improving the detection accuracy of foreign matter 3.

[0068] The banknote handling device 1 of the embodiment is also equipped with a transport mechanism 6 that transports the banknote bundle 2A along the transport path 5, and the transport mechanism 6 has a pair of upper and lower shuttle members 13A and 13B that sandwich and transport the banknote bundle 2A in the thickness direction (Z direction) of the banknote bundle 2A, and the multiple rollers 25 of the pressing unit 8 are provided on the opposing surfaces (lower surface 19 and placing surface 20) of the pair of upper and lower shuttle members 13A and 13B that face each other. As a result, bulging of the paper surface 2s caused by wrinkles or creases in the banknotes 2 of the banknote bundle 2A can be easily suppressed by the multiple rollers 25, and bulging due to foreign matter 3 can be more accurately detected, thereby further improving the accuracy of detecting foreign matter 3.

[0069] Furthermore, the transport mechanism 6 of the banknote handling device 1 of the embodiment has a transfer belt 14 that moves the banknote bundle 2A sandwiched between a pair of upper and lower shuttle members 13A and 13B against a plurality of rollers 25. This makes it possible to press the banknote bundle 2A in the thickness direction (Z direction) of the banknote bundle 2A while rolling the plurality of rollers 25 along the paper surface 2s of the banknote bundle 2A, and any bulging of the paper surface 2s caused by wrinkles or creases in the banknotes 2 of the banknote bundle 2A can be easily suppressed using the plurality of rollers 25, making it possible to more accurately detect bulging of the paper surface 2s caused by a foreign object 3, thereby further improving the accuracy of detecting the foreign object 3.

[0070] Furthermore, the multiple ultrasonic sensors 21 of the detection unit 7 in the banknote handling device 1 of the embodiment are arranged in a grid pattern on a plane (XY plane) perpendicular to the thickness direction (Z direction) of the banknote bundle 2A transported along the transport path 5. This improves the detection accuracy of the foreign object 3 and enables the foreign object 3 to be quickly detected within a predetermined range on the paper surface 2s of the banknote bundle 2.

[0071] Furthermore, the ultrasonic sensors 21 of the detection unit 7 in the banknote handling device 1 of the embodiment irradiate ultrasonic waves with a frequency f of 3.4 MHz or more onto the paper surface 2s of the banknote bundle 2A. This makes it possible to detect a change of 0.1 mm or less in the paper surface 2s caused by a foreign object 3, ensuring an appropriate resolution for detecting foreign objects 3 such as coins. [Explanation of symbols]

[0072] 1. Banknote handling equipment (paper sheet handling equipment) 2. Banknotes (paper sheets) 2A Banknote bundle (bundle of paper sheets) 2s page 3 Foreign object 5 Transport path 6. Conveyor mechanism 7. Detection unit 8 Pressing part 13 Shuttle (transport member) 13A Upper shuttle member (transport member 13B Lower shuttle member (transport member) 14 Transfer belt (moving member) 21 Ultrasonic Sensor 21-1 First ultrasonic sensor 21-2 Second ultrasonic sensor 21-3 Third ultrasonic sensor 25 Laura P1~P3 1st position~3rd position (multiple positions)

Claims

1. a conveyance path along which a bundle of paper sheets is conveyed; a detection unit having a plurality of ultrasonic sensors arranged on the conveying path, and detecting the presence or absence of foreign matter mixed in the bundle of paper sheets by the plurality of ultrasonic sensors; The detection unit emits ultrasonic waves from the multiple ultrasonic sensors toward multiple positions on the surface of the stack of paper sheets transported along the transport path, and detects the presence or absence of the foreign object based on the reflected waves of the ultrasonic waves from the multiple positions.

2. the detection unit repeats the detection of the presence or absence of the foreign matter a plurality of times at regular intervals in the conveying direction of the conveying path with respect to the paper surface.

2. The paper sheet handling device according to claim 1.

3. a pressing unit having a plurality of rollers that press the bundle of paper sheets transported along the transport path in a thickness direction of the bundle of paper sheets, 2. The paper sheet handling device according to claim 1.

4. the plurality of rollers are arranged in a grid pattern on a plane perpendicular to the thickness direction of the stack of paper sheets transported along the transport path; 4. The paper sheet handling device according to claim 3.

5. a conveying mechanism that conveys the bundle of paper sheets along the conveying path; the conveying mechanism includes a pair of conveying members that sandwich and convey the bundle of paper sheets in a thickness direction of the bundle of paper sheets, The plurality of rollers are provided on opposing surfaces of the pair of conveying members, the opposing surfaces being opposed to each other.

5. The paper sheet handling device according to claim 4.

6. the conveying mechanism has a moving member that moves the bundle of paper sheets sandwiched between the pair of conveying members relative to the plurality of rollers; 6. The paper sheet handling device according to claim 5.

7. the plurality of ultrasonic sensors are arranged in a grid pattern on a plane perpendicular to the thickness direction of the bundle of paper sheets transported along the transport path; 2. The paper sheet handling device according to claim 1.

8. The ultrasonic sensors irradiate the paper surfaces of the bundle of paper sheets with ultrasonic waves having a frequency of 3.4 MHz or more.

2. The paper sheet handling device according to claim 1.

9. Conveying a bundle of paper sheets along a conveying path; irradiating ultrasonic waves from a plurality of ultrasonic sensors arranged on the conveying path toward a plurality of positions on a surface of the bundle of paper sheets conveyed along the conveying path; and detecting the presence or absence of a foreign object mixed in the bundle of paper sheets based on the reflected waves of the ultrasonic waves from the plurality of positions.

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