JP2009251690A - Magnetic sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor device capable of performing detection with a high degree of precision while suppressing cost and device space. <P>SOLUTION: The magnetic sensor device comprises a first magnetic field generation means disposed adjacent to one conveyance path face composing a conveyance path, a second magnetic field generation means disposed adjacent to the other conveyance path face composing the conveyance path, the polarity being arranged such that the like-poles face each other with the polarity of the first magnetic field generation means, and a magnetic field change detection means disposed adjacent to the first magnetic field generation means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic sensor device for detecting paper sheets conveyed on a conveyance path at a predetermined interval, and more particularly to a magnetic sensor device capable of performing highly accurate detection while suppressing cost and device space. Is.

  2. Description of the Related Art A magnetic sensor device that detects paper sheets such as banknotes conveyed along a conveyance path is known (see, for example, Patent Document 1 as a technique for detecting a magnetic field change due to a detection target). In such a magnetic sensor device, the conveyance path is usually provided with an interval of several millimeters (about 0.5 mm to 1.6 mm in a part where the magnetic sensor is provided, and about 2.0 mm in other parts). For this reason, the paper sheets are transported while fluttering in the transport path.

  However, in the case of a magnetic sensor device in which a magnetic sensor including a permanent magnet is provided on one of the conveyance path surfaces constituting the conveyance path and the change in the magnetic field generated by the permanent magnet is detected, if such “flapping” occurs, the magnetic The output signal obtained from the sensor becomes unstable.

  The reason is that when the distance from the magnetic sensor to the paper sheet (hereinafter referred to as “depth”) changes due to the flapping of the paper sheet, the magnetic flux generated by the magnet (the strength of the magnetic field increases as the depth from the magnetic sensor increases. This is because it becomes difficult to detect a change in magnetic field.

  For this reason, a technique for bringing paper sheets into close contact with a magnetic sensor has been proposed. For example, a technique is known in which a detection surface of a magnetic sensor is made of wear-resistant ceramics, and then a paper sheet is brought into close contact with the magnetic sensor with a bristle roller having a hair-like material on the surface.

Japanese Utility Model Publication No. 63-87603

  However, there is a problem in that paper jams (conveyance jams) are likely to occur when a technique is used in which paper sheets are brought into close contact with the magnetic sensor using a bristle roller or the like. In addition, when a plurality of magnetic sensors are arranged in a straight line in a direction perpendicular to the transport direction to detect the entire surface of the paper sheet, the projecting area of the magnetic sensor on the transport path increases, and a paper sheet transport jam occurs. Furthermore, it becomes easy to generate.

  Furthermore, in order to prevent wear of the sensor detection surface due to the close contact of the paper sheets, it is necessary to use a member such as the above-mentioned wear-resistant ceramic on the detection surface of the magnetic sensor, which increases the cost of the entire apparatus. There is also a problem.

  It is also possible to suppress fluctuations in the output of the magnetic sensor due to the flapping of the paper sheets by placing the paper sheets opposite to each other on both sides of the transport path instead of closely contacting the banknotes to the magnetic sensor. However, twice as many magnetic sensors are required and the cost is high. In particular, when the magnetic sensors are arranged in a straight line and the entire sheet is detected, the problem of cost becomes significant. In addition, when the magnetic sensors are provided on both sides of the conveyance path, there is a problem that the apparatus itself is enlarged.

  From these facts, how to realize a magnetic sensor device that is non-contact type that allows flapping of paper sheets and that can perform highly accurate detection while suppressing cost and device space is a major issue. It has become.

  The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a magnetic sensor device capable of performing highly accurate detection while suppressing cost and device space.

  In order to solve the above-described problems and achieve the object, the present invention provides a magnetic sensor device for detecting paper sheets conveyed on a conveyance path at a predetermined interval, and one conveyance that constitutes the conveyance path. The first magnetic field generating means provided adjacent to the road surface and the other magnetic path generating surface constituting the transport path are provided adjacent to each other so that the polarities of the first magnetic field generating means are opposite to each other. And a magnetic field change detecting means provided adjacent to the first magnetic field generating means.

  In the present invention, the magnetic force generated by the second magnetic field generating means is equal to or greater than the magnetic force generated by the first magnetic field generating means.

  Further, the present invention is the above invention, wherein the magnetic field change detecting means includes a magnetic field passing means made of a magnetic material in which one pole and the other pole in the first magnetic field generating means are connected in a U shape, An interval holding unit made of a non-magnetic material provided so as to separate two adjacent portions of the first magnetic field generating unit and the magnetic field passing unit, and a detecting unit for detecting a change in the magnetic field passed by the magnetic field passing unit And further comprising.

  In the present invention, the distance between the first magnetic field generating means and the second magnetic field generating means is 0.5 mm to 1.0 mm.

  According to the present invention, the first magnetic field generating means provided adjacent to one conveyance path surface constituting the conveyance path, and the first magnetic field provided adjacent to the other conveyance path surface constituting the conveyance path. Since the second magnetic field generating means having a polarity so that the same polarity as the polarity of the generating means are opposed to each other and the magnetic field change detecting means provided adjacent to the first magnetic field generating means are provided. By providing the second magnetic field generating means at a position facing the first magnetic field generating means across the conveying path, even if the paper sheet flutters in the conveying path, the magnetic field change detecting means The output value can be stabilized, and an effect that highly accurate detection can be performed is achieved. In addition, since there is no need for the paper sheets to be brought into close contact with the conveyance path surface, the cost can be reduced. Further, the apparatus space can be reduced as compared with the case where an opposing mechanism such as a roller or a magnetic sensor is provided at a position facing the first magnetic field generating means across the conveyance path.

  Further, according to the present invention, the magnetic force generated by the second magnetic field generating means is equal to or greater than the magnetic force generated by the first magnetic field generating means, so that the magnetic field change in the conveyance path width direction is changed. By suppressing, the depth characteristic in which the output value of the magnetic field change generating means decreases with the distance (depth) between the first magnetic field generating means and the paper sheet can be improved.

  According to the present invention, the magnetic field change detecting means includes a magnetic field passing means made of a magnetic material in which one pole and the other pole of the first magnetic field generating means are connected in a U shape, and the first magnetic field generating means. Since it further comprises a gap holding means made of a non-magnetic material provided so as to separate two adjacent portions of the means and the magnetic field passing means, and a detecting means for detecting a change in the magnetic field passed by the magnetic field passing means. By detecting not only the magnetic field generated by the first magnetic field generating means but also the magnetic field generated by the second magnetic field generating means through the magnetic field passing means, highly accurate magnetic detection is possible regardless of the depth of the paper sheet. There is an effect that can be performed.

  Further, according to the present invention, since the distance between the first magnetic field generating means and the second magnetic field generating means is 0.5 mm to 1.0 mm, the paper sheet is improved while improving the depth characteristic. There is an effect that conveyance clogging (conveyance jam) can be prevented.

  Hereinafter, preferred embodiments of a magnetic sensor device according to the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, after describing the problems of the magnetic sensor device according to the prior art, examples of the magnetic sensor device according to the present invention will be described.

  FIG. 5 is a block diagram showing a configuration of a magnetic sensor device 50 according to the prior art. As shown in the figure, a magnetic sensor device 50 according to the prior art is provided adjacent to a magnet 51 such as a permanent magnet, a bristle roller 52 for bringing paper sheets into close contact with the conveyance path surface, and the magnet 51. And a magnetic field change detection unit 53.

  And the conveyance path in the magnetic sensor device 50 according to the prior art is configured as a space sandwiched between the conveyance path surface 101 a on the side where the magnet 51 is provided and the conveyance path surface 101 b corresponding to the outer periphery of the bristle roller 52.

  Here, in the case of a single channel sensor composed of a pair of permanent magnets 51 and a magnetic field change detection unit 53, the conveyance path interval 102 is about 0.0 mm (close contact), and a plurality of sets of permanent magnets 51 and a magnetic field change detection unit. In the case of a line sensor in which 53 is linearly arranged in the direction perpendicular to the conveyance direction, the distance is adjusted to about 0.0 mm to 0.3 mm. In addition, 100d of the same figure shows the paper sheet used as a detection target.

  As described above, the magnetic sensor device 50 according to the related art is provided on the side facing the magnetic sensor so that the paper sheet 100d is in close contact with the magnetic sensor including the magnet 51 and the magnetic field change detection unit 53. A method of pressing with a facing mechanism such as a bristle roller 52 has been adopted. This is because as the distance (depth) between the magnet 51 and the paper sheet increases, the output of the magnetic sensor tends to decrease, making it difficult to detect the magnetism with high accuracy.

  However, when a method of providing a counter mechanism as in the conventional magnetic sensor device 50 is employed, there is a problem that the device space of the magnetic sensor device increases. In addition, when the paper sheet is brought into close contact with the magnetic sensor, the paper sheet is easily jammed (conveyance jam) and the detection surface of the magnetic sensor is made of a wear-resistant ceramic to prevent the sensor detection surface from being worn. There is a problem that the cost of the entire apparatus increases.

  Therefore, in the magnetic sensor device according to the present invention, a magnet such as a permanent magnet and a magnetic field change detection unit are provided on one conveyance path surface constituting the conveyance path while the non-contact type apparatus having a predetermined conveyance path interval is provided. By providing only a magnet such as a permanent magnet on the transfer path surface, the above-described problems related to the prior art were solved. Below, the Example of the magnetic sensor apparatus which concerns on this invention is described using FIGS. 1-4.

  FIG. 1 is a block diagram illustrating a configuration of a magnetic sensor device 10 according to the present embodiment. As shown in the figure, the magnetic sensor device 10 includes a magnet 11 such as a permanent magnet provided on the conveyance path surface 1 a side, a magnet 12 such as a permanent magnet provided on the conveyance path surface 1 b side, and an S pole in the magnet 11. A core 13 linking the N pole and the N pole, a spacer 14 provided between the end portions of the core 13 adjacent to the magnet 11, a detection circuit 15, and a coil 16 connected to the detection circuit 15. Composed.

  The magnetic field change detection unit 17 including the magnet 11, the core 13, the spacer 14, the detection circuit 15, and the coil 16 corresponds to the magnetic field change detection unit 53 illustrated in FIG. Further, the magnet 11 and the magnetic field change detection unit 17 may be collectively referred to as a magnetic sensor.

  Here, the conveyance path interval 2, which is the distance between the conveyance path surface 1a and the conveyance path surface 1b, is adjusted to be about 0.5 mm to 1.0 mm. That is, as shown in 100a, 100b, and 100c in the same figure, the paper sheets that are transported on the transport path are transported with a degree of freedom in the interval direction of the transport path.

  The magnet 12 is provided adjacent to the conveyance path surface 1b so that the north pole of the magnet 12 faces the north pole of the magnet 11 and the south pole of the magnet 12 faces the south pole of the magnet 11. Here, it is preferable to use a magnet 12 having a magnetic force higher than that of the magnet 11. For example, as the magnet 11, a magnet having a magnetic force of 1000 gauss or more is used, and as the magnet 12, a magnet having a magnetic force larger than that of the magnet 11 is used.

  The core 13 is made of a magnetic material such as sendust, permalloy, or ferrite having a high magnetic permeability. The spacer 14 is made of a nonmagnetic material such as brass or bronze. The detection circuit 15 detects a magnetic field change in the core via the coil 16 wound around the core 13.

  As described above, the magnetic sensor device 10 is a non-contact type device that detects magnetism without bringing a paper sheet to be detected into close contact with the conveyance path surface. And the magnet 12 is provided in the position which opposes the magnet 11 by the side of a conveyance path on the magnetic sensor side, and the position of paper sheets changes like 100a, 100b, or 100c by generating the magnetic flux of a conveyance path space | interval direction. Even in this case, the rate of change of magnetic flux is suppressed. This makes it possible to perform stable magnetic detection regardless of the depth of the paper sheet, while being a non-contact type.

  Next, the magnetic field generated by the magnet 11 and the magnet 12 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a diagram illustrating a magnetic field when a magnet is provided on one side of the conveyance path and a magnetic field when a magnet is provided on both sides. In addition, (1) of the figure shows the magnetic field when a magnet is provided on one side of the conveyance path, and (2) of the figure shows the magnetic field when a magnet is provided on both sides of the conveyance path. .

  As shown in FIG. 2 (1), when the magnet 11 is provided on one side of the transport path, the magnetic lines generated by the magnet 11 are magnetic lines 11a that are substantially parallel to the transport direction in the transport path. And magnetic field lines 11b passing through the core.

  Here, since the direction of the magnetic force lines 11a in the transport path has many components parallel to the transport path surface, the amount of magnetic flux change increases as the depth of the paper sheets increases (when the distance from the magnet 11 increases). Along with this, the amount of change in magnetic flux due to the change in the depth of the paper sheets also increases in the core. Therefore, the difference in signal amplitude of the magnetic sensor at each depth tends to increase.

  On the other hand, as shown in (2) of the figure, when the magnet 12 and the magnet 11 are provided on both sides of the conveyance path, the lines of magnetic force are directed from the magnet 12 to the core and through the core to the magnet 12. 12b occurs. That is, when the magnet 12 is provided, a magnetic flux in a direction perpendicular to the conveyance path (up and down direction in the figure) is generated, so that the amount of change in the magnetic flux in the vertical direction depending on the paper sheet position becomes small.

  Note that the amount of magnetic flux change in the horizontal direction (left and right in the figure) in the transport path is the same as in the case of (1) in the figure, but considering the sum of the amount of magnetic flux change in the vertical and horizontal directions as a whole. Specifically, the amount of magnetic flux change due to the paper sheet position is small. Along with this, the amount of change in magnetic flux due to the change in the depth of the paper sheet is also reduced in the core. Therefore, the difference in the signal amplitude of the magnetic sensor at each depth is small, so that stable magnetic detection is possible even when the depth of the paper sheet changes.

  Next, the relationship between the sensor output and the depth in the magnetic sensor device 10 will be described with reference to FIG. FIG. 3 is a diagram illustrating the relationship between sensor output and depth. In addition, 31 of the figure shows a graph when there is no counter magnet (magnet 12), and 32 of the figure shows a distance between the magnets (conveyance path interval) of 1.0 mm with the counter magnet (magnet 12). In FIG. 33, there are shown graphs when the counter magnet (magnet 12) is provided and the distance between the magnets (conveyance path interval) is 0.5 mm.

  In addition, the broken line part in the graph 32 and the graph 33 is an estimated line showing an estimated value. Also, the vertical axis in the figure represents the relative value when the output value when the conveyance path interval is 0.05 mm is 100, and the horizontal axis in the figure represents the distance between the magnet 11 and the paper sheet. Depth is shown respectively.

  As shown at 31 in the figure, when there is no counter magnet (magnet 12), the output tends to decrease in proportion to the increase in depth. On the other hand, as shown in 32 of the same figure, when the opposing magnet (magnet 12) is provided with the conveyance path interval of 1.0 mm, the depth of 0.05 mm to 0.25 mm is 31 of the same figure. Although it is the same as (without magnet), in the section where the depth is 0.25 mm to 0.45 mm, the decrease in output accompanying the increase in depth is alleviated.

  For example, when the depth is 0.45 mm, the output of 31 (in the case of no magnet) in the figure is 34, but the output of 32 in the figure (in the case of having a magnet and a conveyance path interval of 1.0 mm) is 57. So there is a 23 percent improvement.

  In addition, as shown in FIG. 33, when the opposing magnet (magnet 12) is provided with a transport path interval of 0.5 mm, the depth of 0.05 mm to 0.1 mm is 31 (no magnet). However, in the section where the depth is 0.15 mm and after, the output drop accompanying the increase in the depth is remarkably improved as compared with 32 (conveyance path interval 1.0 mm) in FIG.

  For example, when the depth is 0.25 mm, the output of 31 (no magnet) in the figure is 59, and the output of 32 (conveyance path interval 1.0 mm) in the figure is 60, but 33 ( Since the output of the conveyance path interval (0.5 mm) is 78, an improvement of 18 to 19% is observed.

  Next, a circuit example of the detection circuit 15 illustrated in FIG. 1 will be described with reference to FIG. FIG. 4 is a diagram illustrating a circuit example of the detection circuit 15. Note that (1) in the figure shows a circuit example suitable for configuring a single-channel magnetic sensor using a pair of magnets 11, magnets 12 and the magnetic field change detection unit 17 (2 in the figure). ) Respectively show circuit examples suitable for configuring a plurality of magnetic sensors as line sensors.

  As shown in (1) of the figure, the signal value from the coil 16 is amplified by the amplifier 15a, rectified by the full-wave rectifier 15b for both positive and negative waves in the alternating current, and converted into a current in the same direction. The Then, a high frequency component is cut to remove a noise component by an LPF (Low Pass Filter) 15c, and the analog signal is converted to a digital signal by an AD converter 15d. The digital signal output from the AD converter 15d is stored in a memory (not shown).

  Further, as shown in (2) of the figure, the signal value from the coil 16 is amplified by an amplifier 15e and converted from an analog signal to a digital signal by an AD converter 15f. Then, the noise component is cut by the noise cut 15g, and stored in a memory (not shown) through integration processing by the digital integration 15h. Note that the digital processing shown in the figure may be configured as a circuit or a program executable by a computer.

  As described above, according to the present embodiment, the first magnetic field generating means provided adjacent to one transport path surface constituting the transport path and the other transport path surface configuring the transport path are adjacent to each other. A second magnetic field generation unit provided with a polarity so that the same polarity as the polarity of the first magnetic field generation unit is opposed to each other; and a magnetic field change detection unit provided adjacent to the first magnetic field generation unit Since the magnetic sensor device is configured so as to provide the second magnetic field generating means at a position opposed to the first magnetic field generating means across the conveying path, the paper sheets flutter in the conveying path. Even in such a case, the output value of the magnetic field change detection means can be stabilized, and highly accurate detection can be performed.

  Moreover, since it is not necessary to make paper sheets contact | adhere to a conveyance road surface, cost can be suppressed. Furthermore, the apparatus space can be reduced as compared with the case where an opposing mechanism such as a roller or a magnetic sensor is provided at a position facing the first magnetic field generating means across the conveyance path.

  As described above, the magnetic sensor device according to the present invention is useful for the detection of paper sheets conveyed on the conveyance path, and in particular, reliably detects bills including magnetic patterns and magnetic threads at a low cost. This is suitable for the case where the user wants to construct a space-saving sensor device.

It is a block diagram which shows the structure of the magnetic sensor apparatus which concerns on a present Example. It is a figure which shows the magnetic field in the case of providing a magnet in the case where a magnet is provided in the single side | surface of a conveyance path, and both surfaces. It is a figure which shows the relationship between a sensor output and depth. It is a figure which shows the circuit example of a detection circuit. It is a block diagram which shows the structure of the magnetic sensor apparatus based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Conveyance path surface 2 Conveyance path space | interval 10 Magnetic sensor apparatus 11, 12 Magnet 13 Core 14 Spacer 15 Detection circuit 15a Amplifier 15b Full wave rectifier 15c LPF (low-pass filter)
15d AD converter 15e Amplifier 15f AD converter 15g Noise cut 15h Digital integration 16 Coil 17 Magnetic field change detection unit 50 Magnetic sensor device according to the prior art 51 Magnet 52 Bristle roller 53 Magnetic field change detection unit 100a, 100b, 100c, 100d Paper sheet Class 101a, 101b Transport path surface 102 Transport path interval

Claims (4)

A magnetic sensor device for detecting paper sheets conveyed on a conveyance path at a predetermined interval,
First magnetic field generating means provided adjacent to one of the conveyance path surfaces constituting the conveyance path;
A second magnetic field generation means provided adjacent to the other conveyance path surface constituting the conveyance path, and having a polarity arranged so that the same polarity as the polarity of the first magnetic field generation means faces each other;
A magnetic sensor device comprising: a magnetic field change detecting means provided adjacent to the first magnetic field generating means. The magnetic force generated by the second magnetic field generating means is
The magnetic sensor device according to claim 1, wherein the magnetic sensor device is equal to or greater than a magnetic force generated by the first magnetic field generation unit. The magnetic field change detecting means includes
Magnetic field passing means made of a magnetic material in which one pole and the other pole in the first magnetic field generating means are connected in a U-shape;
An interval holding means made of a non-magnetic material provided to separate two adjacent portions of the first magnetic field generating means and the magnetic field passing means;
The magnetic sensor device according to claim 1, further comprising: a detecting unit that detects a change in the magnetic field that the magnetic field passing unit passes. The distance between the first magnetic field generating means and the second magnetic field generating means is
The magnetic sensor device according to claim 1, wherein the magnetic sensor device is 0.5 mm to 1.0 mm.

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