JP4267271B2 - Magnetic detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic material detection apparatus that magnetically detects a small amount of magnetic material contained in ink used for printing paper sheets such as securities.
[0002]
[Prior art]
For example, as a measure to prevent counterfeiting of securities such as banknotes, these magnetic inks and belt-like magnets are used at the distribution stage by printing with magnetic ink or using a paper with a long and narrow strip-like magnetic material in securities paper. It is widely known to use it as a means for determining the authenticity of securities by detecting the body.
[0003]
Conventionally, in order to detect a magnetic substance contained in printing ink used for printing such securities, for example, a primary winding is wound around the center of an S-shaped core and set to a minute gap. A secondary winding is wound around each of the two openings, and the securities are passed close to one of the openings, and the difference between the induced voltages of the two secondary windings is output. A small gap is provided in a part of an annular core provided with a differential winding type transformer system or a primary winding and a secondary winding, a direct current is applied to the primary winding, and a magnetic material is placed on the gap. A direct current excitation method that detects changes in magnetic flux in the annular core when passing through the induced voltage of the secondary winding, and a small gap is provided in a part of the annular core provided with the winding, and the upper part is magnetized. Impedance that detects the change of magnetic flux in the annular core as the body passes through as the impedance change of the annular core winding A method using a magnetic head that detects by contact with a magnetic material, such as a system, and further, a magnetic field bias is applied to the magnetoresistive element by a permanent magnet, and the change of the magnetic field due to the proximity of the magnetic material to the magnetoresistive element is detected. There is a method of detecting the change in the resistance value of the magnetoresistive element.
[0004]
Further, as a conventional example for detecting a residual magnetic material, a technique described in Japanese Patent Laid-Open No. 2000-99788 is known. In this magnetic head device and identification device, the primary side of one magnetic head is constituted by an excitation coil, and the secondary side is constituted by a detection coil. A magnetic head that generates an AC magnetic field by applying an AC voltage to the primary side exciting coil and detects an induced voltage induced on the secondary side by electromagnetic induction by a secondary side detection coil is used. Based on the presence or absence of an induced voltage detected by the secondary detection coil when the AC magnetic field is zero, it is determined whether or not the magnetic material used for the detected medium has a residual magnetic material. .
[0005]
[Problems to be solved by the invention]
There are various methods for detecting paper sheets such as securities, as described above for magnetic substance detection devices. In the differential winding transformer method and impedance method, excitation by alternating current is used. Therefore, the circuit becomes complicated because an AC oscillation circuit is required, and the circuit becomes simpler than the differential winding type transformer method in the DC excitation method, but the output signal from the magnetic material is influenced by the moving speed of the magnetic material. Since it is proportional, the signal value is not necessarily proportional to the amount of magnetic material.
[0006]
In addition, the magnetoresistive element method is obtained because of the structure in which two magnetoresistive elements are arranged on the same plane in order to reduce the influence of temperature drift, and the magnetic field strength difference between the two magnetoresistive elements is output as a signal. The signal is not the amount of magnetic substance on the magnetoresistive element, but the spatial difference in quantity of magnetic substance on the two magnetoresistive elements, and is not an accurate magnetic substance amount signal.
[0007]
As described above, in the conventional method, in order to obtain a detection signal proportional to the amount of the magnetic substance contained in the printing ink of the securities, an AC excitation current is required, and the circuit is complicated. In addition, there are limits to manufacturing at low cost due to manufacturing and processing restrictions.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive magnetic material detection device that can obtain a detection signal proportional to the amount of magnetic material by a simple means that does not require an AC excitation current.
[0009]
Another object of the present invention is to provide a magnetic body detection device that distinguishes between a residual magnetic body and a non-residual magnetic body.
[0010]
[Means for Solving the Problems]
The magnetic body detection device of the present invention includes a permanent magnet, a first Hall element for detection that is placed on one pole of the permanent magnet and is opposed to the object to be detected, and the other of the permanent magnets A compensation second Hall element installed at the pole of the first and second bias elements, biasing means for biasing each of the first and second Hall elements, an output signal of the first Hall element and the second Hall element Signal processing means for obtaining a difference from the output signal of the element.
[0011]
In addition, the magnetic body detection device of the present invention is arranged in parallel to a direction orthogonal to the transport direction of the object to be transported and is magnetized in a rectangular short-side direction, and one of the permanent magnets A plurality of first Hall elements for detection that are arranged at predetermined intervals in the long side direction of the poles of the first electrode and are opposed to the object to be detected, and the plurality of first Hall elements in the long side direction of the other pole of the permanent magnet. A plurality of compensation second Hall elements arranged in pairs so as to be opposed to each other and the plurality of first Hall elements, and the plurality of first and second Hall elements, respectively. Energizing means for energizing, and signal processing means for obtaining a difference between each output signal of the plurality of first Hall elements and each output signal of the plurality of second Hall elements for each Hall element pair, respectively It has.
[0013]
Further claims of the present invention 10 The magnetic substance detection device described is a permanent magnet, a first Hall element for detection that is disposed on one pole of the permanent magnet and is opposed to the object to be detected, and the other of the permanent magnets A first detection unit configured by a compensation second Hall element disposed on the pole of the first detection unit, and disposed downstream of the first detection unit in the transport direction of the detection object, An insulator having substantially the same shape as the permanent magnet of one detection unit; a third Hall element for detection disposed on one of the insulators and opposed to the object to be detected; and the insulator A second detection unit configured with a compensation fourth Hall element disposed on the other of the first, second Hall element, a difference between output signals of the first and second Hall elements, and third and fourth Hall elements And a signal processing means for comparing the difference between the two output signals. .
[0014]
Further, the claims of the present invention 13 The described magnetic body detection device is arranged in parallel to a direction orthogonal to the transport direction of the object to be transported, and is a permanent magnet magnetized in a direction perpendicular to the detection surface for detecting the object to be detected. A plurality of first Hall elements for detection that are arranged at a predetermined pitch in the long side direction of one pole of the permanent magnet and are opposed to the object to be detected, and the long side of the other pole of the permanent magnet A first detection unit comprising a plurality of compensation second Hall elements arranged in a direction opposite to each other and in pairs with the plurality of first Hall elements; An insulator that is disposed downstream of the first detection unit in the conveyance direction of the detection object and has substantially the same shape as the permanent magnet of the first detection unit, and one of the insulators has a predetermined length in the long side direction. A plurality of third Hall elements for detection that are arranged at a pitch of and are opposed to the object to be detected; A plurality of fourth Hall elements for compensation arranged on the other side of the insulator and arranged in pairs to be opposed to the plurality of third Hall elements in the long side direction. A difference between each configured second detection unit, each output signal of the plurality of first Hall elements, and each output signal of the plurality of second Hall elements is obtained for each Hall element pair. And signal processing means for obtaining a difference between each output signal of the plurality of third Hall elements and each output signal of the plurality of fourth Hall elements for each pair of Hall elements. It is characterized by.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
First, the first embodiment will be described.
[0017]
FIG. 1 schematically shows a configuration of a magnetic material detection device according to the first embodiment, for example, for detecting a small amount of magnetic material contained in ink used for printing securities. In FIG. 1, reference numeral 1 denotes a securities as a detected object, which has a magnetic material 1a such as magnetic ink printed on the surface thereof, and is conveyed in the direction indicated by an arrow A by being sandwiched by a conveyance belt (not shown). And
[0018]
A detector 2 is disposed opposite to the surface of the securities 1 to be conveyed. The detection unit 2 is in close contact with one pole (for example, N pole) of the permanent magnet 3 and one of the permanent magnets 3 disposed so that one pole (for example, N pole) faces the surface of the securities 1. Fixed Hall element for detection (first Hall element) 4, compensation Hall element (second Hall element) 5 fixed on the other pole (for example, S pole) of permanent magnet 3, permanent magnet 3, and a protective case 7 that is fixed to the base 6 so as to surround the detection Hall element 4 and the permanent magnet 3 side.
[0019]
The protective case 7 protects the detection Hall element 4 and prevents dust or magnetic powder from directly adhering to the permanent magnet 3 or the Hall element 4. Bronze).
[0020]
In such a configuration, the magnetic lines of force output from the north pole of the permanent magnet 3 return to the south pole, but some of the lines of magnetic force penetrate the hall elements 4 and 5, respectively. At this time, by applying a substantially equivalent voltage or current to each power supply terminal of the Hall elements 4 and 5, a voltage proportional to the density of the magnetic field lines is output to each signal terminal of the Hall elements 4 and 5.
[0021]
In the case of FIG. 1, the detection Hall element 4 and the compensation Hall element 5 are arranged at symmetrical positions of the N pole and S pole of the permanent magnet 3 and are under substantially the same magnetic flux density. Is done.
[0022]
The permanent magnet 3 applies a constant bias magnetic field to the Hall elements 4 and 5, and this bias magnetic field is disturbed by the magnetic body 1 a on the securities 1 to increase or decrease the magnetic flux density penetrating the Hall element 4 for detection. . This increase / decrease in magnetic flux density results in an increase / decrease in the output signal of the detection Hall element 4.
[0023]
Now, when the securities 1 are transported and the magnetic body 1a approaches the detection surface (the upper surface of the protective case 7) 2a of the detection unit 2, a part of the lines of magnetic force are attracted to the magnetic body 1a. When the density of magnetic lines of force penetrating the element 4 changes and the magnetic body 1 a comes on the detection Hall element 4, the magnetic flux density penetrating the detection Hall element 4 becomes maximum.
[0024]
On the other hand, the density of the lines of magnetic force of the compensating Hall element 5 does not change because the distance from the magnetic body 1a is long. As a result, a difference occurs between the output voltages of the detection Hall element 4 and the compensation Hall element 5. If this voltage difference is taken out, the detection signal changed by the magnetic substance can be taken out.
[0025]
Further, the magnetic flux density penetrating the detection Hall element 4 is changed by the magnetic material 1a on the securities 1. The amount of change is proportional to the amount of the magnetic material or the magnetic permeability of the magnetic material. Generally, since the magnetic substance mixed with the magnetic ink printed on the securities 1 has uniform characteristics, the amount of change in magnetic flux density can be regarded as being proportional to the amount of magnetic substance. Therefore, the output signal difference between the detection Hall element 4 and the compensation Hall element 5 is a signal proportional to the amount of the magnetic material.
[0026]
When securities having different magnetic characteristics, for example, two types of magnetic inks having magnetic materials with different magnetic permeability are detected, the detected signals are regarded as signals having a difference in the amount of magnetic materials.
[0027]
Although the output voltages of the Hall elements 4 and 5 change depending on the ambient temperature change, the Hall elements 4 and 5 are housed in the case 7 of the detection unit 2, respectively. Therefore, even if the ambient temperature changes, by taking the difference between the output signals of the two Hall elements 4 and 5, it is possible to cancel the fluctuation of the signal due to the temperature and to detect the amount of magnetic material stably.
[0028]
FIG. 2 shows an urging means for the Hall elements 4 and 5 and a signal processing circuit for processing the output signals of the Hall elements 4 and 5. In FIG. 2, a DC power supply unit 10 as an urging means generates a constant current or a constant voltage and supplies it to one of the power supply terminals 4a and 5a of the Hall elements 4 and 5, whereby the Hall elements 4 and 5 are supplied. Energize. The other power supply terminals 4b and 5b of the hall elements 4 and 5 are grounded.
[0029]
Both signal terminals 4 c and 4 d of the Hall element 4 are connected to both input terminals of the differential amplifier 11, and both signal terminals 5 c and 5 d of the Hall element 5 are connected to both input terminals of the differential amplifier 12. . The output terminals of the differential amplifiers 11 and 12 are connected to both ends of the variable resistor 13 so that the polarities of the respective signal outputs are opposite. The movable terminal of the variable resistor 13 is connected to the input terminal of the DC amplifier 14. In this case, setting is made by moving the movable terminal of the variable resistor 13 so that the output signal of the DC amplifier 14 becomes 0V in the state where the magnetic body 1a is not present on the detection surface 2a of the detection unit 2 (zero point adjustment). ).
[0030]
In this state, when the magnetic body 1a comes on the detection surface 2a of the detection unit 2, the signal output of the detection Hall element 4 increases, so that the zero balance is lost and the output signal of the detection Hall element 4 changes. .
[0031]
Next, a second embodiment will be described.
[0032]
FIG. 3 schematically shows the configuration of the magnetic body detection device according to the second embodiment. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, the description is abbreviate | omitted, and only a different part is demonstrated.
[0033]
In the second embodiment, the permanent magnet 3 is formed in a rod shape, and the rod-shaped permanent magnet 3 is attached to the sensor holder 8. The area of the surface to which the Hall elements 4 and 5 of the permanent magnet 3 are in close contact is set to be smaller than the area of the Hall elements 4 and 5, and the detection Hall element 4 detects the change in magnetic flux density with higher sensitivity. It is something that can be done.
[0034]
In FIG. 1, the area of the portion where the permanent magnet 3 and the Hall elements 4, 5 face each other is larger than the Hall elements 4, 5, and therefore the surface of the Hall elements 4, 5 that faces the permanent magnet 3. The density distribution of the magnetic flux inside is almost uniform. Therefore, even if a magnetic substance approaches a small distance from the detection hall element 4 or a minute magnetic body, even if a small change occurs in the magnetic field, the magnetic flux density in the plane of the detection hall element 4 is uniform and averaged. Therefore, it is difficult to detect as a change in magnetic flux.
[0035]
On the other hand, in the case of FIG. 3, the area of the portion where the permanent magnet 3 and the Hall elements 4 and 5 face each other is smaller than that of the Hall elements 4 and 5. The density distribution of the magnetic flux in the plane facing the magnet 3 is a non-uniform distribution that is large at the center and small at the periphery. For this reason, a change in magnetic flux density is likely to occur in the plane of the detection Hall element 4, and it reacts with high sensitivity to a small magnetic field change.
[0036]
Next, a third embodiment will be described.
[0037]
FIG. 4 schematically shows the configuration of the magnetic body detection device according to the third embodiment. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, the description is abbreviate | omitted, and only a different part is demonstrated.
[0038]
As described above, since the area of the portion where the permanent magnet 3 and the Hall elements 4 and 5 face each other is larger than that of the Hall elements 4 and 5 as in FIG. The magnetic flux density distribution in the surface facing the permanent magnet 3 is substantially uniform. In the third embodiment, plate-like magnetic materials 9 and 10 are disposed in the vicinity of the permanent magnet 3 in order to destroy this uniform magnetic flux density distribution. Since the magnetic materials 9 and 10 disperse the magnetic flux of the permanent magnet 3 to the magnetic materials 9 and 10 side, the magnetic flux density distribution in the surface facing the permanent magnet 3 of the Hall elements 4 and 5 becomes uneven, and the magnetic material Improve the detection sensitivity.
[0039]
In the present embodiment, the magnetic material 9 is disposed on the upstream side in the transport direction of the permanent magnet 3 with respect to the transport direction A of the securities 1, and the magnetic material 10 is disposed on the downstream side in the transport direction of the permanent magnet 3. The distance b between the magnetic materials 9 and 10 and the side surface of the permanent magnet 3 is preferably equal to or larger than the distance a between the upper surface of the permanent magnet 3 and the case 7.
[0040]
Next, a fourth embodiment will be described.
[0041]
FIGS. 5A and 5B schematically show the configuration of the magnetic body detection device according to the fourth embodiment. The same parts as those in the first embodiment will be described with the same reference numerals.
[0042]
In the fourth embodiment, a plurality of detection units made up of a pair of Hall elements are arranged in a direction orthogonal to the conveyance direction A of the securities 1 to detect magnetic materials distributed in the width direction of the securities 1. Is made possible.
[0043]
5 (a) and 5 (b), a detection unit 20 is disposed opposite to the surface of the securities 1 to be conveyed. The detection unit 20 is arranged in parallel to the direction orthogonal to the conveyance direction A of the securities 1 so that one pole (for example, the N pole) faces the surface of the securities 1, and the short side direction of the rectangle A plurality of Hall elements for detection (first holes) closely fixed in a row at a predetermined interval in the long side direction on one pole (for example, N pole) of the permanent magnet 21. Elements) 221 to 22n and fixed to each other in a row so as to face each other and form a pair with the detection hall elements 221 to 22n in the long side direction on the other pole (for example, the S pole) of the permanent magnet 21. A plurality of compensation Hall elements (second Hall elements) 23 1 to 23 n, a base 24 for fixing the S pole side of the permanent magnet 21, and a detection Hall elements 221 to 22 n and the permanent magnet 21 side surrounding the base Protective case fixed to 24 And it is made of 25.
[0044]
The protective case 25 protects the detection Hall elements 221 to 22n and prevents dust and magnetic powder from directly adhering to the permanent magnet 21 and the Hall elements 221 to 22n. (For example, phosphor bronze).
[0045]
In the case of this embodiment, the hall element urging means and the signal processing circuit use a plurality (n) of the circuits shown in FIG. 2 because there are a plurality of pairs (n pairs) of hall elements. .
[0046]
In FIG. 5, a plurality of Hall elements 221 to 22n and 231 to 23n are arranged in a line in the long side direction of the permanent magnet 21, but the present invention is not limited to this. For example, as shown in FIG. In addition, the permanent magnets 21 may be arranged in a staggered manner in the long side direction.
[0047]
5 is the same as that shown in FIG.
[0048]
Next, a fifth embodiment will be described.
[0049]
FIG. 7 schematically shows a configuration of a magnetic body detection device according to the fifth embodiment. In the fifth embodiment, plate-like magnetic materials 26 and 27 are disposed in the vicinity of the permanent magnet 21 as in the third embodiment, as compared to the fourth embodiment. In this case, the magnetic material 26 is disposed on the upstream side of the permanent magnet 21 and the magnetic material 27 is disposed on the downstream side of the permanent magnet 21 with respect to the conveyance direction A of the securities 1. As a result, the magnetic materials 26 and 27 disperse the magnetic flux of the permanent magnet 21 toward the magnetic materials 26 and 27, so that the magnetic flux density distribution in the surface facing the permanent magnet 21 of the Hall elements 221 to 22n and 231 to 23n is It becomes uneven and improves the detection sensitivity of the magnetic material.
[0050]
In addition, since the other structure is the same as that of 4th Embodiment, the same code | symbol is attached | subjected to the same part and the description is abbreviate | omitted. Moreover, the cross-sectional view in the YY arrow direction in FIG. 7 is the same as FIG.
[0051]
In FIG. 7, a plurality of Hall elements 221 to 22n and 231 to 23n are arranged in a line in the long side direction of the permanent magnet 21, but the present invention is not limited to this. For example, as shown in FIG. In addition, the permanent magnets 21 may be arranged in a staggered manner in the long side direction.
[0052]
Next, a sixth embodiment will be described.
[0053]
FIGS. 9A and 9B schematically show the configuration of the magnetic body detection device according to the sixth embodiment. The sixth embodiment is different from the fourth embodiment in that it is in contact with the permanent magnet 21 of the detection Hall elements 221 to 22n between the detection Hall elements 221 to 22n and the permanent magnet 21. Also, magnetic materials 281 to 28n having small surfaces are arranged, and these magnetic materials 281 to 28n are held and fixed by a holder 29.
[0054]
With this configuration, the magnetic flux density of the bias magnetic field of the permanent magnet 21 in the detection Hall elements 221 to 22n becomes inhomogeneous, and the detection sensitivity of the magnetic substance in the ink printed on the securities 1 can be increased. it can.
[0055]
In addition, since the other structure is the same as that of 4th Embodiment, the same code | symbol is attached | subjected to the same part and the description is abbreviate | omitted.
[0056]
Next, a seventh embodiment will be described.
[0057]
FIG. 10 schematically shows the configuration of a Hall element suitable for use as the Hall element in the first to sixth embodiments described above, according to the seventh embodiment. In FIG. 10, the Hall element 40 includes a rectangular insulator 42 formed on a rectangular base 41, and a plurality of semiconductor Hall element chips 431 to 43n are arranged at predetermined intervals in the long side direction on the insulator 42. It is arranged in a row.
[0058]
The plurality of semiconductor Hall element chips 431 to 43n are formed in, for example, a quadrangle having a side of about 0.1 mm to 1.0 mm, and each power supply terminal is connected in series as shown in FIG. In addition to the power terminals 45 and 46 of the Hall element 40, the respective signal terminals are similarly connected in series to form signal terminals 47 and 48 of the Hall element 40.
[0059]
The Hall element 40 thus configured has a detection width larger than the detection width of the single semiconductor Hall element chip, and the final detection signal is the output voltage of each of the plurality of semiconductor Hall element chips 431 to 43n. Addition voltage. In actual use, a predetermined DC voltage or current is applied by connecting a DC power supply unit between the power supply terminals 45 and 46 via the resistor R.
[0060]
By using the Hall element 40 configured in this way as the Hall elements 4 and 5 or 22 1 to 22 n and 23 1 to 23 n in the first to sixth embodiments, the detection width of one Hall element can be reduced. It is very suitable for detecting the amount of magnetic material in the width direction of the securities 1.
[0061]
The connection method of the plurality of semiconductor Hall element chips is not limited to the series connection as described above, and each power supply terminal is connected in parallel or in combination of series and parallel to be the power supply terminal of the Hall element. The signal terminals of the Hall element may be connected by connecting each signal terminal in parallel or a combination of series and parallel.
[0062]
In FIG. 10, a plurality of semiconductor Hall element chips 431 to 43n are arranged in a row in the long side direction on the insulator 42. However, the present invention is not limited to this. For example, as shown in FIG. The zigzag may be arranged in the long side direction on the insulator 42.
[0063]
As described above, according to the above-described embodiment, two Hall elements, which are cheaper than the magnetic head and the magnetoresistive element, are used as detection elements, and one Hall element is used for detection and the other Hall element is used as a detection element. A detection unit is provided near the detection Hall element for compensation, and the difference between the output signals of both Hall elements is obtained to eliminate the effect of temperature drift and obtain a detection signal proportional to the amount of magnetic material. In addition, it is possible to realize an inexpensive magnetic substance detection device including a signal processing circuit that does not require an AC excitation current in the circuit.
[0064]
In addition, a magnetic substance amount distribution in the width direction of the securities is detected by arranging a plurality of detection units made up of a pair of Hall elements in the direction perpendicular to the direction of conveyance of the securities to constitute a detection unit. Can be realized at low cost.
[0065]
Furthermore, the Hall element is usually composed of a semiconductor Hall element chip formed in a square shape having a side of about 0.1 mm to 1.0 mm, but its width is narrow for use in detecting the amount of magnetic substance of securities. Therefore, by arranging a plurality of semiconductor Hall element chips in a row and forming one Hall element having a detection width of about 3 mm to 30 mm, the detection width of one Hall element is widened. It is extremely suitable for detecting the amount of magnetic material in the width direction of securities.
[0066]
Next, an eighth embodiment will be described.
[0067]
FIG. 13 conceptually shows a magnetic body detection device according to the eighth embodiment for identifying, for example, the residual magnetic body 102a and the non-remaining magnetic body 102b used for printing the detected object 101. . In FIG. 13, an object to be detected 101 is a security printed with magnetic ink having a residual magnetic body 102a and a non-residual magnetic body 102b, and is sandwiched by a transport belt (not shown) and transported in the direction indicated by the arrow A. And
[0068]
A first detection unit 110 is disposed opposite to the surface of the object 101 to be conveyed. The first detection unit 110 includes a permanent magnet 111 disposed so that one pole (for example, N pole) is opposed to the surface of the detection object 101, and one pole (for example, for example, the permanent magnet 111). The Hall element for detection (first Hall element) 112 tightly fixed on the N pole), and the compensation Hall element (second hole) fixedly fixed on the other pole (for example, the S pole) of the permanent magnet 111 Hall element) 113, a base 115 for fixing the permanent magnet 111, and a protective case 114 that surrounds the detection Hall element 112 and the permanent magnet 111 and is fixed to the base 115.
[0069]
The protective case 114 protects the detection Hall element 112 and prevents dust or magnetic powder from directly adhering to the permanent magnet 111 or the Hall element 112. Bronze).
[0070]
Next, the second detection unit 120 is arranged on the downstream side of the first detection unit 110 with respect to the medium conveyance direction. The second detection unit 120 is obtained by replacing the permanent magnet 111 of the first detection unit 110 with an insulator 121 having substantially the same shape, so that the first detection is performed in a space where there is no exciting magnetic field by the permanent magnet (magnetic field zero state). Hall elements 122 and 123 are arranged in the same manner as the section 110.
[0071]
FIG. 14 shows signal processing means of the first detection unit 110 and the second detection unit 120. FIG. 14A is a first signal processing circuit that processes the biasing means of the Hall elements 112 and 113 of the first detection unit 110 and the output signals of the Hall elements 112 and 113.
[0072]
The DC power supply unit 119e generates a constant current or a low voltage and is connected to one of the power supply terminals 112a and 113a of the Hall elements 112 and 113, and the other power supply terminal 112b and 113b of the Hall elements 112 and 113 is grounded. Is done.
[0073]
In this way, the Hall elements 112 and 113 are energized.
[0074]
Both signal terminals 112c and 112d of the Hall element 112 are connected to both input terminals of the differential amplifier 119a.
[0075]
Both signal terminals 113c and 113d of the Hall element 113 are connected to both input terminals of the differential amplifier 119b.
[0076]
The output terminals of the differential amplifiers 119a and 119b are connected to both ends of the variable resistor 119c so that the polarities of the signal outputs of the differential amplifiers 119a and 119b are opposite. The movable terminal of this variable resistor is connected to the input terminal of the DC amplifier 119d.
[0077]
FIG. 14B is a second signal processing circuit that processes the urging means of the Hall elements 122 and 123 of the second detection unit 120 and the output signals of the Hall elements 122 and 123. This signal processing circuit has the same configuration as that shown in FIG.
[0078]
Here, the zero point adjustment of the first signal processing circuit and the second signal processing circuit will be described. Zero point adjustment means setting the output signal 1 of the first signal processing circuit and the output signal 2 of the second signal processing circuit to 0 V in a state where no magnetic material is detected.
[0079]
Specifically, the output signal 1 of the DC amplifier 119d and the output signal 2 of the 129d are respectively in a state where the magnetic body 102 does not exist on the detection surfaces 114a and 124a of the first detection unit 110 and the second detection unit 120. The movable terminals of the variable resistors 119c and 129c are set so as to be 0V.
[0080]
In such a configuration, the magnetic lines of force output from the north pole of the permanent magnet 111 in FIG. 13 return to the south pole, but some of the lines of magnetic force penetrate the hall elements 112 and 113, respectively. At this time, by applying a substantially equal voltage or current to each power supply terminal of the Hall elements 112 and 113, a voltage proportional to the magnetic flux density is output to each signal terminal of the Hall elements 112 and 113.
[0081]
Since the detection Hall element 112 and the compensation Hall element 113 are disposed at symmetrical positions of the N pole and S pole of the permanent magnet 111 and are under substantially the same magnetic flux density, they are approximately equal when there is no magnetic disturbance. Voltage is output.
[0082]
The permanent magnet 111 applies a constant bias magnetic field to the Hall elements 112 and 113, and this bias magnetic field is generated by the magnetic body 102 (a general term for the residual magnetic body 102a and the non-residual magnetic body 102b) on the detection target 101. The magnetic flux density penetrating through the detection Hall element 112 increases or decreases. This increase / decrease in the magnetic flux density results in an increase / decrease in the output signal of the detection Hall element 112.
[0083]
Now, when the detected object 101 is transported and the magnetic body 102 approaches the detection surface (upper surface of the protective case 114) 114a of the first detection unit 110, a part of the lines of magnetic force is attracted to the magnetic body 102. Therefore, when the magnetic flux density penetrating the detection hall element 112 changes and the magnetic body 102 comes on the detection hall element 112, the magnetic flux density penetrating the detection hall element 112 is maximized.
[0084]
On the other hand, the magnetic flux density of the compensation Hall element 113 does not change because the distance from the magnetic body 102 is long. As a result, a difference occurs between the output voltages of the detection Hall element 112 and the compensation Hall element 113. If this voltage difference is taken out, a detection signal changed by the magnetic material can be taken out.
[0085]
This detection signal is proportional to the amount of magnetic material or the magnetic permeability of the magnetic material. In general, since the magnetic substance mixed with the magnetic ink printed on the detection object 101 has uniform characteristics, the amount of change in magnetic flux density can be regarded as being proportional to the amount of magnetic substance. Therefore, the output signal difference between the detection Hall element 112 and the compensation Hall element 113 is a signal proportional to the amount of the magnetic material.
[0086]
In the case of detecting securities printed with two types of magnetic inks having different magnetic properties, for example, magnetic materials having different magnetic permeability, the detected signals are equivalently different signals in the amount of magnetic material.
[0087]
Although the output voltages of the hall elements 112 and 113 change depending on the ambient temperature change, the hall elements 112 and 113 have substantially the same temperature because they are housed in the case 114 of the first detection unit 110, respectively. Therefore, even if the ambient temperature changes, by taking the difference between the output signals of the two Hall elements 112 and 113, it is possible to cancel the fluctuation of the signal due to the temperature and to detect the amount of the magnetic material stably.
[0088]
Here, the characteristics of the residual magnetic ink (residual magnetic material) and the non-residual magnetic ink (non-residual magnetic material) will be described with reference to FIGS.
[0089]
FIG. 15A is a diagram showing the magnetic characteristics of the residual magnetic material. The residual magnetic body has a hysteresis characteristic as shown in the figure in a certain magnetic field, and the magnetic values at the points A and B in the figure remain in the residual magnetic body when the magnetic field is zero (H = 0).
[0090]
FIG. 15B is a diagram showing the magnetic characteristics of the non-residual magnetic material. As shown in the figure, the non-residual magnetic substance has zero residual magnetic quantity when the magnetic field is zero (H = 0).
[0091]
In the first detection unit 110 in FIG. 13, the amount of magnetic material corresponding to the magnitude of the magnetic field of the permanent magnet 111 is detected for both the residual magnetic material 102 a and the non-residual magnetic material 102 b. That is, the amount of magnetic material of the magnetic ink is detected regardless of the persistence and non-residual properties.
[0092]
In the second detection unit 120, the residual magnetic material 102 a detects the amount of residual magnetic material due to the residual magnetism according to the magnetic field magnitude of the permanent magnet 111 of the first detection unit 110. On the other hand, since the non-residual magnetic body 102b has a magnetic field of zero (H = 0), no magnetic output is detected. By comparing these signals, residual magnetic material and non-residual magnetic material are distinguished.
[0093]
Next, a method for discriminating between residual magnetic material and non-residual magnetic material will be described.
[0094]
FIG. 16 identifies the residual magnetic material and the non-residual magnetic material from the output signal of the first detection unit and the output signal of the second detection unit when the detected object 101 is conveyed in the direction of the arrow A shown in the figure. It is the figure which showed the method.
[0095]
FIG. 16A shows a state in which the detected object 101 having the residual magnetic body 102a and the non-residual magnetic body 102b is conveyed in the direction of the arrow A in the drawing.
[0096]
FIG. 16B shows an output signal of the first detection unit 110, which is a difference signal between the output signal of the Hall element 112 and the output signal of the Hall element 113 of the first detection unit. This signal is output as a magnetic signal in both cases of the residual magnetic body 102a and the non-residual magnetic body 102b by the bias magnetic field generated by the permanent magnet 111 (output signal 1).
[0097]
FIG. 16C shows an output signal of the second detection unit 120, which is a difference signal between the output signal of the Hall element 122 and the output signal of the Hall element 123 of the second detection unit. Since this signal has no bias magnetic field, a magnetic signal is output only in the case of the residual magnetic body 102a (output signal 2).
[0098]
FIG. 16 (d) shows a difference signal obtained by the difference between the output signal 1 of FIG. 16 (b) and the output signal 2 of FIG. 16 (c). The magnetic body 102b to which the difference signal is output is a non-residual magnetic body, and the magnetic body 102a to which the difference signal is not output is a residual magnetic body.
[0099]
Here, the magnetic flux distribution and the magnetic flux density distribution of the present embodiment will be described with reference to FIG.
[0100]
FIG. 17 shows a magnetic flux distribution and a magnetic flux density distribution of the magnetic body identification device according to the eighth embodiment. FIG. 17A shows the magnetic flux distribution, and FIG. 17B shows the magnetic flux density distribution.
[0101]
Since the permanent magnet 111 is larger than the Hall elements 112 and 113 in the area where the permanent magnet 111 faces the Hall element 112 and the Hall element 113 (not shown), the permanent magnet 111 of the Hall elements 112 and 113 is. The density distribution of the magnetic flux in the plane facing the surface becomes substantially uniform. Therefore, even if the magnetic body approaches a place slightly away from the detection Hall element 112 or a small change in the magnetic field is caused by the minute magnetic body, the magnetic flux density in the surface of the detection Hall element 112 is uniform and averaged. Therefore, it is difficult to detect the change of magnetic flux.
[0102]
As described above, the magnetic body identification device according to the eighth embodiment is not suitable for detecting a minute magnetic body with high sensitivity, but the magnetic ink used for printing in a wide range having a large magnetic permeability. In the case of detection of a magnetic substance, it is possible to detect strongly and stably against magnetic disturbance.
[0103]
Next, a ninth embodiment will be described.
[0104]
FIG. 18 schematically shows a configuration of a magnetic body detection device according to the ninth embodiment. Note that the same portions as those in the eighth embodiment are denoted by the same reference numerals, description thereof is omitted, and different portions are described. In the ninth embodiment, the permanent magnet 131 is formed in a rod shape, and the rod-shaped permanent magnet 131 is attached to the sensor holder 136. The area of the surface of the permanent magnet 131 where the Hall elements 132 and 133 are in close contact with each other is set to be smaller than the area of the Hall elements 132 and 133 so that the detection Hall element 132 can detect a change in magnetic flux density with higher sensitivity. It is something that can be done.
[0105]
Here, the magnetic flux distribution and magnetic flux density distribution of the present embodiment will be described with reference to FIG. FIG. 19 shows a magnetic flux distribution and a magnetic flux density distribution of the magnetic body identification device according to the ninth embodiment. FIG. 19A shows the magnetic flux distribution, and FIG. 19B shows the magnetic flux density distribution.
[0106]
The area of the portion where the permanent magnet 131 faces the Hall element 132 and the Hall element 133 (not shown) is smaller than the Hall elements 132 and 133 in the permanent magnet 131, so that the permanent magnet 131 of the Hall elements 132 and 133 is. The magnetic flux density distribution in the plane facing the surface is an uneven distribution that is large at the center and small at the periphery. For this reason, a change in magnetic flux density is likely to occur in the plane of the detection Hall element 132, and it reacts with high sensitivity to a small change in magnetic flux density.
[0107]
As shown in FIG. 18, the residual magnetic material and the non-residual magnetic material can be distinguished by disposing the second detection unit 120 downstream of the first detection unit 130 in the transport direction with respect to the detection object 101. .
[0108]
Next, a tenth embodiment will be described.
[0109]
FIG. 20 schematically shows a configuration of a magnetic body detection device according to the tenth embodiment. Note that the same portions as those in the eighth embodiment are denoted by the same reference numerals, description thereof is omitted, and different portions are described.
[0110]
The area of the portion where the permanent magnet 111 and the Hall elements 112 and 113 face each other is larger than the Hall element 112 and 113 because the permanent magnet 111 is larger than the area of the magnetic flux in the plane where the Hall elements 112 and 113 face the permanent magnet 111. The density distribution is almost uniform. In the tenth embodiment, plate-like magnetic materials 117 and 118 are disposed in the vicinity of the permanent magnet 111 in order to destroy this uniform magnetic flux density distribution.
[0111]
In the present embodiment, the magnetic material 117 is disposed on the upstream side in the transport direction of the permanent magnet 111 with respect to the transport direction A of the detected object 101, and the magnetic material 118 is on the downstream side in the transport direction of the permanent magnet 111. The distance b between the magnetic materials 117 and 118 and the side surface of the permanent magnet 111 is preferably equal to or larger than the distance a between the upper surface of the permanent magnet 111 and the case 114a.
[0112]
With the above configuration, the magnetic materials 117 and 118 disperse the magnetic flux of the permanent magnet 111 toward the magnetic materials 117 and 118, so that the magnetic flux density distribution in the surface of the Hall elements 112 and 113 facing the permanent magnet 111 is uneven. Thus, the detection sensitivity of the magnetic material is improved.
[0113]
Here, the magnetic flux distribution and magnetic flux density distribution of the present embodiment will be described with reference to FIG.
[0114]
FIG. 21 is a magnetic flux distribution and a magnetic flux density distribution of the magnetic body identification device according to the tenth embodiment. 21A shows the magnetic flux distribution, and FIG. 21B shows the magnetic flux density distribution. The magnetic flux density distribution at the approximate center of the portion where the Hall element 112 and the magnet 111 face each other shows that the magnetic flux distribution in the opposite surface is non-uniformly distributed compared to FIG. Show.
[0115]
In FIG. 20, the residual magnetic material and the non-residual magnetic material can be distinguished by disposing the second detection unit 120 downstream of the detected object 101 in the transport direction of the first detection unit 110A.
[0116]
Next, an eleventh embodiment will be described.
[0117]
FIG. 22 schematically shows the configuration of the magnetic substance detection device according to the eleventh embodiment. FIG. 22A is a cross-sectional view of the first detection unit 150 and the second detection unit 160 as viewed from above when the detected object 101 is conveyed in the A direction. FIG.22 (b) is AA arrow sectional drawing of Fig.22 (a).
[0118]
The eleventh embodiment is configured by arranging a plurality of detection units composed of a pair of Hall elements in a direction perpendicular to the conveyance direction A of the detected object 101.
[0119]
22A and 22B, a first detection unit 150 is disposed so as to face the surface of the detected object 101 to be conveyed. The first detection unit 150 is arranged in parallel to the direction orthogonal to the conveyance direction A of the detected object 101 such that one pole (for example, the N pole) faces the surface of the detected object 101, A rectangular permanent magnet 151 magnetized in the short-side direction, and a plurality of detection Hall elements that are closely fixed in a row at predetermined intervals in the long-side direction on one pole (for example, N pole) of the permanent magnet 151 (First Hall element) 1521 to 152n, in close contact with the detection Hall elements 1521 to 152n in the long side direction on the other pole (for example, S pole) of the permanent magnet 151 so as to be paired with each other. A plurality of fixed compensation Hall elements (second Hall elements) 1531 to 153n, a base 155 for fixing the S pole side of the permanent magnet 151, and the detection Hall elements 1521 to 152n and the permanent magnet 151 side are surrounded. do it The protective case 154 is fixed to the base 155.
[0120]
The protective case 154 protects the detection Hall elements 1521 to 152n and prevents dust or magnetic powder from directly adhering to the permanent magnet 151 or the Hall elements 1521 to 152n. (For example, phosphor bronze).
[0121]
Next, the Hall element urging means and the signal processing circuit of the present embodiment will be described.
[0122]
FIG. 23 is a diagram showing the Hall element urging means of FIG. 22 showing the eleventh embodiment and a signal processing circuit for processing the output signal of the Hall element. FIG. 23A shows the signal processing circuit of the first detection unit, and FIG. 23B shows the signal processing circuit of the second detection unit.
[0123]
The DC power supply unit 220 shown in FIG. 23A generates a constant current or a low voltage and is connected to one power supply terminal a of each of the Hall elements 1521 to 152n, and the other of the Hall elements 1521 to 152n. The power supply terminal b is grounded. In this way, the Hall elements 1521 to 152n are energized.
[0124]
The Hall elements 1521 to 152n are detection Hall elements of the first detection unit, and their output terminals are connected to the differential amplifiers 201 to 20n and amplified. The output signal of this amplifier is connected to one input terminal of the differential amplifiers 211 to 21n.
[0125]
In addition, the outputs 1531OUT to 153nOUT of the compensation Hall element of the first detection unit are connected to the other input terminals of the differential amplifiers 211 to 21n, respectively, and magnetic output signals 1521OUT to 152nOUT are obtained.
[0126]
In this case, the zero point adjustment is performed in FIG. 14. However, when the number of Hall elements increases, setting using the variable resistors individually requires that the mounting space for the variable resistors is required Since a zero adjustment is required, another approach is taken. For example, the magnetic output signals 1521OUT to 152nOUT are converted into digital data by A / D conversion (analog / digital conversion) processing (not shown), and this data is taken in by the host CPU. At this time, the noise component is removed by comparing the data for each Hall element when reading the object to be detected and the data for each Hall element before reading the object to be detected for each output of each Hall element. The same performance as when the variable resistor is used can be obtained.
[0127]
FIG. 23B shows a signal processing circuit of the second detection unit.
[0128]
The DC power supply unit 220 shown in FIG. 23B generates a constant current or a low voltage and is connected to one power supply terminal a of each of the Hall elements 1621 to 162n, and the other of the Hall elements 1621 to 162n. The power supply terminal b is grounded. In this way, the Hall elements 1621 to 162n are energized.
[0129]
Hall elements 1621 to 162n shown in the drawing are detection Hall elements of the second detection unit, and their output terminals are connected to the differential amplifiers 221 to 22n and amplified. The output signal of this amplifier is connected to one input terminal of the differential amplifiers 231 to 23n.
[0130]
The outputs 1631OUT to 163nOUT of the compensation Hall element of the second detection unit are connected to the other input terminals of the differential amplifiers 231 to 23n, respectively, and magnetic output signals 1621OUT to 162nOUT are obtained. The magnetic output signals 1621OUT to 162nOUT are converted into digital data by the A / D conversion (analog / digital conversion) processing of the output signal of the first detection unit, and the magnetic signal is processed by the same processing as that performed by the upper CPU. Can be detected.
[0131]
By disposing the second detection unit 160 on the downstream side of the first detection unit 150 with respect to the conveyance direction of the detection object 101, the residual magnetic material and the non-residual magnetic material can be distinguished.
[0132]
In FIG. 22, the plurality of Hall elements 1521 to 152n and 1531 to 153n are arranged in a line in the long side direction of the permanent magnet 151, but the present invention is not limited to this. For example, FIG. 24 is a diagram showing a modification of the Hall element arrangement method according to the eleventh embodiment. In this modification, Hall elements are arranged in a staggered manner in the long side direction of the permanent magnet 171. Further, in order to distinguish between the residual magnetic body 102a and the non-residual magnetic body 102b, a second detection unit 180 configured with an insulating permanent magnet portion is provided downstream in the transport direction.
[0133]
With the above configuration, a magnetic material distributed in the width direction of the detection object 101 can be detected.
[0134]
Next, a twelfth embodiment will be described.
[0135]
FIG. 25 schematically shows a configuration of a magnetic body detection device according to the twelfth embodiment. Note that the same parts as those in the eleventh embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described.
[0136]
In the twelfth embodiment, plate-like magnetic materials 157 and 158 are disposed in the vicinity of the permanent magnet 151, as in the tenth embodiment. In this case, the magnetic material 157 is disposed on the upstream side in the transport direction of the permanent magnet 151 with respect to the transport direction A of the detected object 101, and the magnetic material 158 is disposed on the downstream side in the transport direction of the permanent magnet 151. .
[0137]
Thereby, the magnetic materials 157 and 158 disperse the magnetic flux of the permanent magnet 151 to the magnetic materials 157 and 158 side. Permanent magnets 151 of detection Hall elements 1521 to 152n, and compensation Hall elements 1531 to 153n (not shown) that are fixed in close contact with the detection Hall elements 1521 to 152n so as to face each other. The in-plane magnetic flux density distribution is non-uniform and the detection sensitivity of the magnetic material is improved.
[0138]
Other configurations are the same as those of the eleventh embodiment.
[0139]
In order to identify the residual magnetic body 102a and the non-residual magnetic body 102b, a second detection unit 160 made of an insulating permanent magnet portion is disposed on the downstream side in the transport direction.
[0140]
In FIG. 25, a plurality of Hall elements 1521 to 152n and 1531 to 153n are arranged in a line in the long side direction of the permanent magnet 151, but the present invention is not limited to this. For example, FIG. 26 is a diagram showing a modification of the Hall element arrangement method according to the twelfth embodiment. In this modification, Hall elements are arranged in a staggered manner in the long side direction of the permanent magnet 171, and the second detection unit 180 configured by an insulator made of a permanent magnet portion is disposed on the downstream side in the transport direction. The residual magnetic material and the non-residual magnetic material are distinguished by
[0141]
Next, a thirteenth embodiment will be described.
[0142]
FIG. 27 schematically shows a configuration of a magnetic body detection device according to the thirteenth embodiment. FIGS. 27A and 27C are side sectional views of the detection object 101, the first detection unit 190, and the second detection unit 160. FIG. FIGS. 27B and 27D are cross-sectional views taken along the line BB in FIGS. 27A and 27B. Note that the same parts as those in the eleventh embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described.
[0143]
Compared to the eleventh embodiment, the thirteenth embodiment is a surface between the detection Hall elements 1921 to 192n and the permanent magnet 191 that is in close contact with the permanent magnet 191 of the detection Hall elements 1921 to 192n. In addition, magnetic materials 1961 to 196n having smaller surfaces are arranged, and these magnetic materials 1961 to 196n are held and fixed by a holder 197.
[0144]
With such a configuration, the magnetic flux density of the bias magnetic field of the permanent magnet 191 in the detection Hall elements 1921 to 192n becomes inhomogeneous, and the detection sensitivity of the magnetic substance in the ink printed on the detection object 101 is increased. be able to. Similarly, the residual magnetic body and the non-residual magnetic body are identified by disposing a second detection unit 160 configured with a permanent magnet portion as an insulator holder on the downstream side of the detected object 101 in the transport direction. . Other configurations are the same as those of the eleventh embodiment.
[0145]
As described above, according to the above-described embodiment, a plurality of inexpensive Hall elements are used as a detection element compared to a magnetic head or a magnetoresistive element, and the detection Hall element is disposed on one of the permanent magnets. On the other hand, a detector having a compensating Hall element is disposed on the upstream side in the transport direction, and a detector having the permanent magnet made of an insulator is disposed downstream in the transport direction. By using the difference between the output signals, it becomes possible to obtain a detection signal proportional to the amount of magnetic material by removing the influence of temperature drift, and a magnetic material detection device for discriminating between residual magnetic material and non-residual magnetic material. Can be realized. In addition, an inexpensive magnetic substance detection device having a signal processing circuit that does not require an AC excitation current in the circuit can be realized.
[0146]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide an inexpensive magnetic body detection device and Hall element that can obtain a detection signal proportional to the amount of magnetic body by a simple means that does not require an AC excitation current. Further, it is possible to provide a magnetic body identification device that distinguishes a residual magnetic body and a non-residual magnetic body.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view schematically showing a configuration of a magnetic substance detection device according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram showing a hall element urging means and a signal processing circuit for processing an output signal of the hall element.
FIG. 3 is a longitudinal side view schematically showing a configuration of a magnetic body detection device according to a second embodiment of the present invention.
FIG. 4 is a longitudinal side view schematically showing a configuration of a magnetic substance detection device according to a third embodiment of the present invention.
FIGS. 5A and 5B schematically show a configuration of a magnetic substance detection device according to a fourth embodiment of the present invention. FIG. 5A is a cross-sectional view as viewed from above, and FIG. 5B is as viewed from a side. Sectional drawing.
FIG. 6 is a view for explaining a modification of the Hall element disposition method in the fourth embodiment.
FIG. 7 is a cross-sectional view seen from above schematically showing a configuration of a magnetic body detection device according to a fifth embodiment of the present invention;
FIG. 8 is a view for explaining a modification of the Hall element arrangement method according to the fifth embodiment.
FIGS. 9A and 9B schematically show a configuration of a magnetic body detection device according to a sixth embodiment of the present invention, wherein FIG. 9A is a cross-sectional view as viewed from the side, and FIG. ZZ arrow sectional drawing in.
FIG. 10 is a configuration diagram schematically showing a configuration of a Hall element according to a seventh embodiment of the present invention.
11 is a connection diagram showing an example of a method for connecting a plurality of semiconductor Hall element chips in FIG.
FIG. 12 is a view for explaining a modification of the semiconductor Hall element chip disposing method in the seventh embodiment.
FIG. 13 is a longitudinal side view schematically showing a configuration of a magnetic body identification device according to an eighth embodiment of the present invention.
FIG. 14 is a diagram showing a signal processing circuit for processing the hall element urging means and the output signal of the hall element.
FIG. 15 is a view showing magnetic characteristics of a residual magnetic material.
FIG. 16 is a diagram showing a method for discriminating residual magnetic material from non-residual magnetic material.
FIG. 17 is a magnetic flux distribution and magnetic flux density distribution diagram of the magnetic body identification device according to the eighth embodiment of the present invention.
FIG. 18 is a longitudinal side view schematically showing a configuration of a magnetic body identification device according to a ninth exemplary embodiment of the present invention.
FIG. 19 is a magnetic flux distribution and magnetic flux density distribution diagram of the magnetic material identifying apparatus according to the ninth embodiment of the present invention.
FIG. 20 is a longitudinal side view schematically showing a configuration of a magnetic body identification device according to a tenth embodiment of the present invention.
FIG. 21 is a magnetic flux distribution and magnetic flux density distribution diagram of the magnetic body identification device according to the tenth embodiment of the present invention.
FIG. 22 is a diagram schematically showing a configuration of a magnetic body identification device according to an eleventh embodiment of the present invention.
23 is a diagram showing a hall element urging means and a signal processing circuit for processing an output signal of the hall element in the case of FIG. 22;
FIG. 24 is a view for explaining a modification of the Hall element arrangement method according to the eleventh embodiment.
FIG. 25 is a diagram schematically showing a configuration of a magnetic body identification device according to a twelfth embodiment of the present invention.
FIG. 26 is a view for explaining a modification of the Hall element arrangement method according to the twelfth embodiment of the present invention.
FIG. 27 is a diagram schematically showing a configuration of a magnetic body identification device according to a thirteenth embodiment of the present invention.
[Explanation of symbols]
1 Securities (Detected object)
1a Magnetic material
2, 20 detector
3, 21 Permanent magnet
4, 5, 22 1 to 22 n, 23 1 to 23 n Hall element
6, 24 base
7, 25 Protective case
8 Sensor holder
9, 10, 26, 27, 281-28n ... magnetic material
29 Holder
10 DC power supply (energizing means)
11,12 Differential amplifier
13 Variable resistor
14 DC amplifier
40 Hall element
41 base
42 Insulator
431 to 43n Semiconductor Hall element chip
45, 46 Power terminal
47, 48 Signal terminal
101 Object to be detected
102a Residual magnetic material
102b Non-residual magnetic material
110, 110A, 130, 150, 150A, 170, 170A, 190 First detection unit
120, 160, 180 Second detection unit
111, 121, 131, 151, 161, 171, 181, 191 Permanent magnet
112, 113, 122, 123, 132, 133 Hall element
114, 124, 134, 154, 164, 174, 184, 94 Protective case
115, 125, 135, 155, 165, 175, 185, 195 base
117, 118 Magnetic material
121, 161, 181 Insulator
136, 197 Sensor holder
1521-152n, 1621-162n, 1631-163n Hall element
1721-172n, 1821-182n, 1921-192n Hall element

Claims (18)

With permanent magnets,
A first Hall element for detection which is installed on one pole of the permanent magnet and is opposed to the object to be detected;
A second Hall element for compensation installed on the other pole of the permanent magnet;
Biasing means for biasing each of the first and second Hall elements;
Signal processing means for determining a difference between an output signal of the first Hall element and an output signal of the second Hall element;
A magnetic substance detection apparatus comprising:   2. The magnetic body detection device according to claim 1, wherein an area of the permanent magnet is smaller than an area of the Hall element on a surface where each pole of the permanent magnet and the first and second Hall elements face each other. .   The magnetic body detection device according to claim 1, further comprising magnetic materials respectively disposed in the vicinity of the upstream side and the downstream side of the permanent magnet with respect to the conveyance direction of the detection object. A permanent magnet that is arranged in parallel to the direction perpendicular to the transport direction of the object to be transported and is magnetized in the rectangular short-side direction;
A plurality of first Hall elements for detection arranged at predetermined intervals in the long side direction of one of the poles of the permanent magnet and opposed to the object to be detected;
A plurality of compensation second Hall elements arranged in pairs to be opposed to the plurality of first Hall elements in the long side direction of the other pole of the permanent magnet;
Biasing means for biasing each of the plurality of first and second Hall elements;
Signal processing means for obtaining a difference between each output signal of the plurality of first Hall elements and each output signal of the plurality of second Hall elements for each Hall element pair;
A magnetic substance detection apparatus comprising:   5. The magnetic body detection device according to claim 4, further comprising magnetic materials respectively disposed in the vicinity of the upstream side and the downstream side of the permanent magnet with respect to the conveyance direction of the detection object.   5. The magnetic material according to claim 4, further comprising a plurality of magnetic materials respectively disposed for each Hall element between the plurality of first Hall elements and one pole of the permanent magnet. Magnetic body detection device.   The area of the plurality of magnetic materials is smaller than the area of the first Hall element on each surface where the plurality of first Hall elements and the plurality of magnetic materials face each other. 6. The magnetic substance detection device according to 6.   5. The magnetic body detection device according to claim 4, wherein the plurality of first Hall elements and second Hall elements are arranged in a line in the long side direction of the permanent magnet.   5. The magnetic body detection device according to claim 4, wherein the plurality of first Hall elements and second Hall elements are arranged in a staggered manner in the long side direction of the permanent magnet. A permanent magnet and a first detection magnet disposed on one pole of the permanent magnet and opposed to the object to be detected. 1 A first detection unit configured by a Hall element of the second and a second Hall element for compensation disposed on the other pole of the permanent magnet;
The first detection unit is disposed downstream in the conveyance direction of the object to be detected, and is disposed on one of the insulators with the same shape as the permanent magnet of the first detection unit. A second detection unit composed of a third Hall element for detection opposed to the object to be detected, and a fourth Hall element for compensation disposed on the other side of the insulator;
A signal processing means for obtaining a difference between output signals of the first and second Hall elements and a difference between output signals of the third and fourth Hall elements and comparing the two differences;
A magnetic substance detection apparatus comprising: The area of the permanent magnet is smaller than the area of the Hall element on the surface where each pole of the permanent magnet of the first detection unit and the first and second Hall elements face each other. The magnetic body detection device according to claim 10.   The magnetic material detection device according to claim 10, wherein a magnetic material is disposed in the vicinity of the upstream side and the downstream side of the permanent magnet of the first detection unit with respect to the conveyance direction of the detection object. A permanent magnet that is arranged in parallel to the direction perpendicular to the conveyance direction of the object to be conveyed and is magnetized in a direction perpendicular to the detection surface for detecting the object to be detected, and the length of one pole of the permanent magnet A plurality of detection first arrays arranged at a predetermined pitch in the side direction and opposed to the object to be detected. 1 And the plurality of second elements in the long side direction of the other pole of the permanent magnet. 1 A first detection unit configured with a plurality of compensation second Hall elements arranged in pairs to face each other of the Hall elements;
An insulator having a shape substantially the same as that of the permanent magnet of the first detection unit is disposed downstream of the first detection unit with respect to the conveyance direction of the detection object. A plurality of detection third Hall elements arranged at a predetermined pitch and opposed to the object to be detected, and the plurality of third holes arranged on the other side of the insulator in the long side direction A second detector configured by a plurality of compensation fourth Hall elements arranged to be opposed to each other and to be paired with each other;
The plurality of second 1 A difference between each output signal of each of the plurality of second Hall elements and each output signal of the plurality of second Hall elements is obtained for each pair of Hall elements, and each of the output signals of the plurality of third Hall elements is A signal processing means for obtaining a difference from each output signal of the plurality of fourth Hall elements for each Hall element pair;
A magnetic substance detection apparatus comprising: The magnetic material detection device according to claim 13, wherein a magnetic material is disposed in the vicinity of the upstream side and the downstream side of the permanent magnet with respect to the conveyance direction of the object to be detected. A plurality of first detectors of the first detector; 1 A plurality of magnetic materials respectively arranged for each Hall element are provided between the Hall element and one pole of the permanent magnet of the first detection unit. Magnetic body detection device. Said 1 A plurality of detectors 1 Hall element and the first 1 The area of each of the plurality of magnetic materials on each surface of the detection unit opposite to the plurality of magnetic materials is the first. 1 The magnetic body detection device according to claim 15, wherein the magnetic body detection device is configured to be smaller than an area of the Hall element. Said 1 Multiple detection units 1 17. The magnetic body detection device according to claim 13, wherein the hall elements and the second hall elements are arranged in a line in a long side direction of the permanent magnet. Said 1 Multiple detection units 1 17. The magnetic body detection device according to claim 13, wherein the hall elements and the second hall elements are arranged in a staggered manner in the long-side direction of the permanent magnet.

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