JP5242698B2 - Magnetic quality detection device - Google Patents

Description

  The present invention relates to a magnetic quality detection device that detects the magnetism of a paper sheet by transporting a paper sheet printed with magnetic ink along a transport surface, and in particular, accurately detects the difference in coercive force characteristics of the magnetic ink. The present invention relates to a magnetic quality detection device capable of detecting.

  Conventionally, magnetic ink containing a magnetic material has been used for printing ink on paper sheets such as banknotes and gift certificates from the viewpoint of preventing counterfeiting. Here, as the magnetic ink, a hard magnetic ink having a large coercive force and a soft magnetic ink having a small coercive force are used in combination, and a difference in the coercive force characteristic of each magnetic ink is detected by a magnetic quality detection device. Thus, the authenticity of the paper sheet is determined.

  For example, Patent Document 1 discloses a magnetic quality detection device that detects the magnetic quality of paper sheets printed with hard magnetic ink and soft magnetic ink. In such a magnetic quality detection device, the magnetic ink is saturated and magnetized, and an appropriate bias magnetic field is applied to detect the hard magnetic ink and the hard / soft mixed magnetic pattern of the soft magnetic ink.

  Then, by applying a bias magnetic field corresponding to the coercivity of the hard magnetic ink, the magnetization of the hard magnetic ink is erased, and only the magnetization of the soft magnetic ink remains. In this case, when the intensity of the bias magnetic field is adjusted so that the residual magnetization of the hard magnetic ink becomes zero in the genuine paper sheet, only the magnetic pattern of the soft magnetic ink is detected in the genuine paper sheet. . Then, by using the previously acquired hard-soft mixed magnetic pattern and the newly acquired soft magnetic pattern, the authenticity of the paper sheet can be determined.

  By the way, in the magnetic quality detection apparatus of patent document 1, a magnet etc. are provided in the single side | surface of the conveyance path of paper sheets, and after making a divergent magnetic field type magnetic field generate | occur | produce in this magnet, paper sheets are passed, Authenticity discrimination of leaves is performed.

Japanese Patent No. 3283931

  However, in the technique of Patent Document 1, the intensity of the bias magnetic field is adjusted so that the residual magnetization of the hard magnetic ink becomes zero with respect to the direction of the perpendicular to the conveyance surface in the conveyance path (hereinafter referred to as “Y direction”). The residual magnetization in the transport direction (hereinafter referred to as “X direction”) in the transport path is not considered.

  However, when a divergent magnetic field type magnetic field is used, the direction of the magnetic field lines is not necessarily parallel to the Y direction, and the magnetic field lines pass through the paper sheet at a predetermined angle. That is, an X-direction component exists in the lines of magnetic force in the divergent magnetic field.

  For this reason, even if the residual magnetization of the hard magnetic ink in the Y direction is zero, the residual magnetization of the hard magnetic ink in the X direction is not necessarily zero. Accordingly, there is a problem that the combined residual magnetization in the X direction and the Y direction cannot be accurately set to 0, and the authenticity determination accuracy cannot be sufficiently increased.

  For these reasons, how to realize a magnetic quality detection device capable of accurately detecting a difference in coercive force characteristics of magnetic ink is a major issue. Such a problem is also a problem that occurs in the paper sheet discriminating apparatus that discriminates the authenticity of the paper sheet using the detection result of the magnetic quality detection apparatus.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a magnetic quality detection device that can accurately detect a difference in coercive force characteristics of magnetic ink.

In order to solve the above-described problems and achieve the object, the present invention provides a magnetic quality detection device for detecting the magnetism of the paper sheet by transporting the paper sheet printed with magnetic ink along the transport surface. A magnet unit in which different poles of magnets are connected by a yoke is disposed at a position facing each other across the transport surface, and the direction of a magnetic vector in the magnetism detection section on the transport surface is the transport surface. And a magnetic field generating means adjusted so that the magnetic field strength in the conveyance direction in the magnetic detection section is monotonously increased, monotonically decreased, or monotonically decreased after the monotonic increase, and provided in the magnetic detection section And a magnetic quality detection means.

  Further, the present invention is characterized in that, in the above invention, each magnet unit of the magnetic field generating means is arranged so that the magnetic poles of the magnets facing each other across the transport surface are different from each other. .

  Further, the present invention is the above invention, wherein the magnetic field generation means further includes a plurality of divided magnetic guide plates divided in the transport direction on the transport surface side of each magnet unit, and the magnetic quality detection means The position corresponding to the divided magnetic guide plate is provided closer to the conveying surface than the divided magnetic guide plate.

  In the present invention according to the present invention, the magnetic field generating means further includes a position adjusting mechanism for adjusting a position of the divided magnetic guiding plate in the transport direction.

  Further, the present invention is the above invention, wherein the magnetic field generation means further includes one magnetic guide plate on the transport surface side of one of the magnet units, and the magnetic quality detection means includes the magnetic guide plate. It is provided closer to the transport surface than the above.

  Further, the present invention is the above invention, wherein the magnetic field generating means adjusts a distance between the transport surface and the one magnet unit by using the magnetic guide plates having different magnetic conductivities and / or plate thicknesses. It is characterized by.

According to the present invention, magnet units in which different poles of magnets are connected by a yoke are arranged at positions facing each other across the conveyance surface, and the direction of the magnetic vector in the magnetism detection section on the conveyance surface is the same as the conveyance surface. Magnetic field generating means that is vertical and adjusted so that the magnetic field strength in the conveyance direction in the magnetic detection section monotonously increases, monotonously decreases, or monotonically decreases after the monotonic increase, and magnetic quality detecting means provided in the detection section Therefore, it is possible to accurately detect the difference in the coercive force characteristics of the magnetic ink by transporting the paper sheet at a position where the direction of the magnetic force line is the perpendicular direction of the paper sheet. Play.

  Further, according to the present invention, each magnet unit of the magnetic field generating means is arranged so that the magnetic poles of the magnets facing each other across the transport surface are different from each other. By configuring this, there is an effect that the direction of the lines of magnetic force can be made the normal direction of the paper sheet.

  Further, according to the present invention, the magnetic field generating means further includes a plurality of divided magnetic guiding plates divided in the conveying direction on the conveying surface side of each magnet unit, and the magnetic quality detecting means is provided on the divided magnetic guiding plates. Since the corresponding position is provided closer to the conveyance surface than the divided magnetic guide plate, the magnetic field strength between the magnet units can be changed stepwise by using the divided magnetic guide plate. Thus, there is an effect that it is possible to widen the allowable range of the displacement of the magnetic quality detection means.

  In addition, according to the present invention, the magnetic field generating means further includes a position adjusting mechanism that adjusts the position of the divided magnetic guide plate in the transport direction, so that the magnetic field strength between the magnet units can be adjusted. Play.

  Further, according to the present invention, the magnetic field generating means further includes one magnetic guide plate on the transport surface side of one magnet unit, and the magnetic quality detection means is provided closer to the transport surface than the magnetic guide plate. By using a single magnetic guide plate for one magnet unit, it is possible to change the position where the direction of the magnetic force line is in the direction perpendicular to the paper sheet to the magnet unit. There is an effect.

  Further, according to the present invention, the magnetic field generating means adjusts the distance between the transport surface and one of the magnet units by using magnetic plates having different magnetic conductivities and / or plate thicknesses. There is an effect that the position in the perpendicular direction of the paper sheet can be adjusted in detail.

FIG. 1 is a diagram illustrating an outline of the magnetic quality detection device according to the first embodiment. FIG. 2 is a diagram illustrating lines of magnetic force and magnetic field strength distribution generated by the magnetic quality detection apparatus according to the first embodiment. FIG. 3 is a diagram showing saturation magnetization curves of hard magnetic ink and soft magnetic ink and values detected by the MR sensor. FIG. 4 is a diagram illustrating an outline of the magnetic quality detection device according to the second embodiment. FIG. 5 is a diagram illustrating a magnetic force line distribution of the magnetic quality detection device according to the second embodiment. FIG. 6 is a diagram showing the relationship between the thickness and magnetic permeability of the magnetic guide plate and the position of the magnetic field inflection point. FIG. 7 is a diagram illustrating a modification of the magnetic quality detection device according to the second embodiment. FIG. 8 is a diagram illustrating an outline of the magnetic quality detection device according to the third embodiment. FIG. 9 is a diagram illustrating lines of magnetic force and magnetic field strength distribution generated by the magnetic quality detection device according to the third embodiment. FIG. 10 is a diagram showing a change in the magnetic field strength distribution when the uppermost divided magnetic guide plate is moved. FIG. 11 is a diagram illustrating a change in magnetic field strength distribution when the most downstream divided magnetic guide plate is moved. FIG. 12 is a diagram showing a modified example of the arrangement of the divided magnetic guide plates. FIG. 13 is a diagram showing the configuration and magnetic field strength distribution of the magnetic quality detection apparatus 1 that supports bidirectional conveyance. FIG. 14 is a diagram showing the configuration and magnetic field strength distribution of the magnetic quality detection apparatus 2 that supports bidirectional conveyance. FIG. 15 is a diagram showing a variation of the paper sheet pressing mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Magnetic quality detection apparatus 101 Conveyance direction 110 Upper unit 111 Yoke 112, 113 Magnet 120 Lower unit 121 Yoke 122, 123 Magnet 124 Substrate 125 MR sensor (MR1)
126 MR sensor (MR2)
200 Magnetic quality detection apparatus 210 Upper unit 211 Yoke 212, 213 Magnet 220 Lower unit 221 Yoke 222, 223 Magnet 224 Substrate 225 MR sensor (MR1)
226 MR sensor (MR2)
227 Magnetic guide plate 300 Magnetic quality detection device 310 Upper unit 311 Yoke 312, 313 Magnet 314a, 314b, 314c, 314d Split magnetic guide plate 320 Lower knit 321 York 322, 323 Magnet 324a, 324b, 324c, 324d Split magnetic guide plate 325 Substrate 326 MR sensor (MR1)
327 MR sensor (MR2)

  Exemplary embodiments of a magnetic quality detection apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the first embodiment, the magnet units are respectively arranged at symmetrical positions across the conveyance path. In the second embodiment, the single magnetic guide plate is arranged on the conveyance path side of one magnet unit. In the third embodiment, a case where a plurality of divided magnetic guide plates divided in the transport direction are arranged on the transport path side of both magnet units will be described.

  FIG. 1 is a diagram illustrating an outline of the magnetic quality detection device 100 according to the first embodiment. As shown in the figure, the magnetic quality detection apparatus 100 according to the first embodiment includes an upper unit 110 provided above the conveyance path and a lower unit 120 provided below the conveyance path. .

  The upper unit 110 has a magnetic field generation unit (magnetic field generation means) in which a magnet 112 and a magnet 113 are connected by a yoke 111 in a housing provided with a wear-resistant material on the conveyance path side. Here, the yoke 111 is a member made of a material having a high magnetic conductivity such as permalloy, for example.

  Further, as shown in the figure, the magnet 112 and the magnet 113 in the upper unit 110 are provided along the lower surface of the housing, and the magnet 112 is upstream in the transport direction 101 and the magnet 113 is downstream. Are arranged. Magnet 112 and magnet 113 may be configured as permanent magnets or as electromagnets.

  The lower unit 120 has a magnetic field generation unit (magnetic field generation means) in which a magnet 122 and a magnet 123 are connected by a yoke 121 in a housing provided with a wear-resistant material on the conveyance path side. Further, as shown in the figure, the magnet 122 and the magnet 123 in the lower unit 120 are provided toward the upper surface of the housing, and the magnet 122 is upstream in the transport direction 101 and the magnet 123 is downstream. Are arranged. Note that the magnet 122 and the magnet 123 may also be configured as permanent magnets or electromagnets, similarly to the magnets 112 and 113.

  In addition, a magnetic quality detection unit (magnetic quality detection means) is provided inside the lower unit 120 along the upper surface of the housing. As shown in the figure, the magnetic quality detection unit is configured by providing an MR (MagnetoResistive) sensor (MR1) 125 and an MR sensor (MR2) 126 on a substrate 124. Here, the MR sensor refers to a sensor whose resistance value changes in accordance with the magnetic field strength. In the first embodiment, a case where an MR sensor is used will be described. However, a Hall sensor, a magnetic impedance sensor, a fluxgate sensor, or the like may be used.

  As shown in the figure, the magnet 112 of the upper unit 110 and the magnet 122 of the lower unit 120 face each other across the transport path. Further, the magnet 113 of the upper unit 110 and the magnet 123 of the lower unit 120 are opposed to each other across the conveyance path. Thus, the upper unit 110 and the lower unit 120 form a closed magnetic path with the conveyance path as an air gap. Hereinafter, the closed magnetic circuit will be described in more detail.

  FIG. 2 is a diagram illustrating lines of magnetic force and magnetic field strength distribution generated by the magnetic quality detection device 100 according to the first embodiment. In addition, (A) of the same figure shows the magnetic force line which the magnetic quality detection apparatus 100 generate | occur | produces, (B) of the same figure each shows magnetic field strength distribution.

  As shown in FIG. 2A, the magnet 112 of the upper unit 110 has an S pole on the conveyance path side and an N pole on the yoke 111 side, and the magnet 122 of the lower unit 120 has an N pole on the conveyance path side and a yoke 121. The side is the S pole. The magnet 113 of the upper unit 110 has an N pole on the conveyance path side and an S pole on the yoke 111 side, and the magnet 123 of the lower unit 120 has an S pole on the conveyance path side and an N pole on the yoke 121 side.

  In this way, each magnet unit (upper unit 110 and lower unit 120) is provided so that the magnets of the opposing magnet units and the opposite poles face each other. At the midpoint of 120, the transfer line 21 is perpendicular. Here, the transport line 21 indicates a position through which the transported paper sheet passes, and the direction of the arrow of the transport line 21 indicates the transport direction.

  That is, on the transport line 21 shown in the figure, the X-direction component of the magnetic force lines is 0 and only the Y-direction component, so that the paper sheets can be magnetized only in the Y direction. Therefore, it is possible to reliably control the magnetization of the subject (paper sheets) and improve the accuracy of coercive force detection.

  Note that the MR sensor (MR1) 125 and the MR sensor (MR2) 126 are disposed in the vicinity of the conveyance line 21 on the conveyance path sandwiched between the upper unit 110 and the lower unit 120, as shown in FIG. By doing in this way, the residual magnetization of the paper sheets magnetized only by the Y direction component can be acquired with high accuracy.

  Further, as shown in (B) of the figure, the magnetic field strength in the closed magnetic circuit formed by the upper unit 110 and the lower unit 120 has no inflection point between the positions 23/26 shown in the figure. This is represented as a non-decreasing curve 22.

  Specifically, the curve 22 does not have an inflection point from the point 22a to the point 22d, and increases monotonously. In this way, by changing the magnetic field intensity so as not to decrease along the saturation magnetization curve, it becomes possible to accurately detect the residual magnetization of the paper sheets saturated and magnetized at the point 22a.

  Here, since the MR sensor (MR1) 125 and the MR sensor (MR2) 126 are respectively arranged at the position 24 and the position 25 shown in the figure, the points included in the non-decreasing section (between the points 22a and 22d). The residual magnetization at 22b and point 22c is detected.

  The position 24 of the MR sensor (MR1) 125 and the position 25 of the MR sensor (MR2) 126 can be any position between the points 22a / 22d. Moreover, although the figure shows the case where two MR sensors detect residual magnetization at two points, the number of MR sensors may be three or more.

  Next, an example of determining the authenticity of a sheet by comparing the detection value by the MR sensor (MR1) 125 and the detection value by the MR sensor (MR2) 126 will be described with reference to FIG. FIG. 3 is a diagram showing saturation magnetization curves of hard magnetic ink and soft magnetic ink and values detected by the MR sensor. Note that (A) in the figure shows the saturation magnetization curve, and (B) in the figure shows the detection value by the MR sensor.

  As shown in FIG. 3A, for example, the soft magnetic ink that is in a saturated magnetization state at the point 32a at the position 23 is MR at the point 32b at the position 24 (attachment position of the MR sensor (MR1) 125). The residual magnetization is detected by the sensor (MR1) 125, and the residual magnetization is detected by the MR sensor (MR2) 126 at a point 32c at the position 25 (attachment position of the MR sensor (MR2) 126).

  Also, the hard magnetic ink that has been in a saturated magnetization state at the point 31a at the position 23 has its residual magnetization detected by the MR sensor (MR1) 125 at the point 31b at the position 24 (attachment position of the MR sensor (MR1) 125). The residual magnetization is detected by the MR sensor (MR2) 126 at a point 31c at the position 25 (attachment position of the MR sensor (MR2) 126). Here, the position 25 (attachment position of the MR sensor (MR2) 126) is adjusted to a position where the magnetization intensity at the point 31c becomes 0 in the case of a genuine paper sheet.

  Therefore, the MR sensor (MR2) 126 does not detect the magnetic pattern of the hard magnetic ink in the case of an authentic paper sheet, and detects the magnetic pattern of the hard magnetic ink in the case of an unauthentic paper sheet. Will do.

  For example, as shown in FIG. 5B, there are three soft magnetic ink lines and two hard magnetic ink lines so that the magnetic ink pattern of a genuine paper sheet intersects the transport line 21. Suppose that it is attached to paper sheets.

  In this case, the detected value of the MR sensor (MR1) 125 arranged at the position 24 is as shown by a curve 33 in FIG. In other words, the MR sensor (MR1) 125 detects both the residual magnetization caused by the soft magnetic ink and the residual magnetization caused by the hard magnetic ink (see 33a in the figure).

  On the other hand, the detected value of the MR sensor (MR2) 126 arranged at the position 25 is as shown by a curve 34 in FIG. That is, the MR sensor (MR2) 126 detects the residual magnetization due to the soft magnetic ink, but does not detect the residual magnetization due to the hard magnetic ink (see 34a in the figure).

  Thus, for authentic paper sheets, the authenticity of the paper sheets can be determined by disposing the MR sensor (MR2) 126 at a position where the residual magnetization of the hard magnetic ink becomes zero. Here, in the magnetic quality detection apparatus 100 according to the first embodiment, the upper unit 110 is configured so that the X component of the magnetic force lines becomes 0 in the paper sheet conveyance line, that is, the magnetic field lines are orthogonal to the conveyance line. Since the closed magnetic path is formed by the lower unit 120, the position where the residual magnetization of the hard magnetic ink becomes 0 can be accurately estimated.

  As described above, in the first embodiment, the upper unit and the lower unit are arranged at symmetrical positions with respect to the paper sheet conveyance line, and the closed magnetic path is configured by the upper unit and the lower unit. The magnetic field lines were made to be orthogonal to the paper sheets being conveyed. Therefore, the magnetic field component parallel to the paper sheet is eliminated and the paper sheet is magnetized only by the magnetic field component orthogonal to the paper sheet, so that the residual magnetization of ink having different magnetic characteristics can be accurately acquired. Can do. As a result, the authenticity of the paper sheet can be determined with high accuracy.

  In the first embodiment, the residual magnetization of the ink having different magnetic characteristics is detected and the authenticity of the paper sheet is determined based on the detected residual magnetization. However, as shown in FIG. In the magnetic quality detection apparatus according to the first embodiment, since the magnetization intensity is changed along the saturation magnetization curve, an absolute magnetic quantity can be detected. Therefore, it is possible to perform authenticity determination based on an absolute magnetic quantity.

  By the way, in Example 1 mentioned above, although it showed about the case where a magnet unit was each arrange | positioned in the symmetrical position about the conveyance line of paper sheets, it arrange | positions a single-sheet magnetism guide plate to the conveyance path side of one magnet unit. Thus, the distance between the transfer line and the magnet unit may be adjusted. Therefore, in Example 2 described below, a case where a single plate of a magnetic guide plate is disposed on the conveyance path side of one magnet unit will be described.

  FIG. 4 is a diagram illustrating an outline of the magnetic quality detection device 200 according to the second embodiment. As shown in the figure, the magnetic quality detection apparatus 200 according to the second embodiment includes an upper unit 210 provided above the conveyance path and a lower unit 220 provided below the conveyance path. The lower unit 220 is different from the magnetic quality detection apparatus 100 according to the first embodiment in that the lower unit 220 includes a magnetic guide plate 227.

  The upper unit 210 includes a yoke 211, a magnet 212, and a magnet 213 in a housing in which a wear-resistant material is provided on the conveyance path side, similarly to the magnetic quality detection device 100 according to the first embodiment. Yes. The lower unit 220 includes a yoke 221, a magnet 222, and a magnet 223 in a housing provided with a wear-resistant material on the conveyance path side, and an MR sensor (MR1) 225 and an MR sensor (MR2). The above-described magnetic guide plate 227 is provided between the substrate 224 provided with H.226, and the magnet 222 and the magnet 223.

  Here, the magnetic guide plate 227 is attached so as not to contact the magnet 222 or the magnet 223 of the lower unit 220. The reason is that when the magnetic guide plate 227 and the magnet (magnet 222 or magnet 223) are brought into contact with each other, a closed magnetic circuit is formed between these members, and a magnetic field is formed between the upper unit 210 and the lower unit 220. Because it will not be done.

  Since the magnetic quality detection apparatus 200 according to the second embodiment includes the magnetic guide plate 227, the position of the line where the magnetic lines of force are perpendicular to the subject (paper sheet) can be drawn toward the lower unit 220 side. That is, according to the magnetic quality detection apparatus 200 according to the second embodiment, the position of the conveyance line where the magnetic force line is only the Y-axis component does not need to be an intermediate point between the upper unit 210 and the lower unit 220.

  Next, the magnetic force line distribution of the magnetic quality detection apparatus 200 according to the second embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a magnetic force line distribution of the magnetic quality detection device 200 according to the second embodiment. Incidentally, (A) in the figure shows the magnetic field line distribution of the magnetic quality detection device 200 according to the second embodiment, and (B) in the same figure shows the magnetic field detection device 100 according to the first embodiment for reference. Magnetic field line distribution is shown respectively.

  As shown in FIG. 5A, in the magnetic quality detection apparatus 200 according to the second embodiment, each magnetic field line is only at the Y-axis component (parallel to the Y-axis) at a position near the lower unit 220. Therefore, the transport line 51 can be set at a position closer to the lower unit 220. Here, the transport line 51 indicates a position through which the transported paper sheet passes, and the direction of the arrow of the transport line 51 indicates the transport direction.

  As shown in FIG. 5B, the conveyance line 21 in the magnetic quality detection device 100 according to the first embodiment needs to be provided at an intermediate point between the upper unit 110 and the lower unit 120. The conveyance line 51 in the magnetic quality detection apparatus 200 according to the above can be provided on the surface of the lower unit 220 having the MR sensor. Therefore, the measurement accuracy of residual magnetization by the MR sensor can be improved.

  Here, in the magnetic quality detection apparatus 200 according to the second embodiment, by changing the thickness (T) and the magnetic permeability (μ) of the magnetic guide plate 227, the magnetic field lines are only Y-axis components (parallel to the Y-axis). It is possible to change the position.

  FIG. 6 is a diagram showing the relationship between the thickness and magnetic conductivity of the magnetic guide plate 227 and the position of the magnetic field inflection point. Here, the magnetic field line inflection point refers to a point on the magnetic field line where the magnetic field line is only the Y-axis component (parallel to the Y axis), and the position of the magnetic field line inflection point refers to the magnetic field line inflection point for each magnetic field line. The distance between the connected line and the conveyance surface (here, the upper surface of the lower unit 220) is represented. It is assumed that a wear-resistant material is applied to the upper surface of the lower unit 220.

  In FIG. 6A, the distance (clearance) between the upper unit 210 and the lower unit 220 is 8.0 mm, and the distance between the magnetic guide plate 227 and the magnets (magnet 222 and magnet 223) is 0. The line of magnetic force when the distance between the magnetic conducting plate 227 and the upper surface of the lower unit 220 is 1 mm is set to 0.5 mm. Further, (B) in the figure shows a graph showing the relationship between the distance (d) between the magnetic field inflection point and the conveying surface and the thickness (T) of the magnetic guide plate 227, and the magnetic permeability ( This is shown for each μ).

  Specifically, the graph representing the relationship between the distance (d) and the thickness (T) is a curve 61 when the magnetic permeability (μ) is 50, and a curve 62 when the magnetic permeability (μ) is 100. Thus, when the magnetic permeability (μ) is 200, the curve 63 is obtained. Further, the curve 64 is obtained when the magnetic permeability (μ) is 500, and the curve 65 is obtained when the magnetic permeability (μ) is 1000.

  As shown in FIG. 6B, the distance (d) tends to decrease as the magnetic permeability (μ) increases and the thickness (T) increases. In other words, the distance (d) tends to increase as the magnetic permeability (μ) decreases and the thickness (T) decreases.

  As described above, there are many combinations of the magnetic permeability (μ) and the thickness (T) for matching the sheet conveyance surface and the inflection point of the magnetic field lines. In order to avoid cracking due to sag and increase in unit size due to thickening, it is preferable that the thickness (T) of the magnetic guide plate 227 is about 0.3 mm to 2.0 mm.

  Therefore, referring to the graph shown in FIG. 6B, the magnetic permeability (μ) and the thickness (T) are set so that the magnetic permeability (μ) is about 100 to 500 and the distance (d) becomes zero. It can be seen that it is sufficient to select. As described above, when the magnetic quality detection device 200 according to the second embodiment is used, the position of the inflection point of the magnetic lines of force can be adjusted near the upper surface of the lower unit 220.

  4 and the like, the yoke 211, the magnet 212, and the magnet 213 constitute the upper unit 210, and the magnet 212 and the magnet 213 are arranged on the conveyance path side. By providing the yoke, the magnetic field strength in the conveyance path may be increased as shown in the following example.

  FIG. 7 is a diagram illustrating a modification of the magnetic quality detection device 200 according to the second embodiment. As shown in the figure, a yoke 81 is further provided on the conveyance path side of the magnet 212 in the upper unit 210. Thus, by providing the yoke 81, the magnetic field strength between the lower unit 220 and the magnet 222 can be increased. Thereby, the magnetism for saturation magnetization of the paper sheet 500 can be enhanced. Here, the conveyance line 82 points to the position through which the conveyed paper sheet passes, and the direction of the arrow of the conveyance line 81 indicates the conveyance direction.

  As described above, in Example 2, the position of the inflection point of the lines of magnetic force is made closer to the upper surface of the lower unit by arranging a single magnetic guide plate on the conveyance path side of the lower unit. In addition, the position of the inflection point of the lines of magnetic force was adjusted by changing the thickness of the magnetic guide plate and the magnetic permeability. Therefore, the MR sensor of the lower unit can detect the residual magnetization of the paper sheet with high accuracy. In addition, the size of the magnetic quality detection device can be reduced.

  By the way, in the above-described second embodiment, the case of using a single-plate magnetic guide plate has been described. However, a plurality of divided magnetic guide plates divided in the transport direction may be used. Therefore, in Example 3 described below, a case where a plurality of divided magnetic guide plates are used will be described.

  FIG. 8 is a diagram illustrating an outline of the magnetic quality detection device 300 according to the third embodiment. As shown in the figure, the magnetic quality detection apparatus 300 according to the third embodiment includes an upper unit 310 provided above the conveyance path and a lower unit 320 provided below the conveyance path. In the first embodiment, the upper unit 310 includes a plurality of divided magnetic guide plates (314a, 314b, 314c and 314d), and the lower unit 320 also includes a plurality of divided magnetic guide plates (324a, 324b, 324c and 324d). It differs from the magnetic quality detection apparatus 100 which concerns.

  Here, the divided magnetic guide plate 314a of the upper unit 310 is opposed to the divided magnetic guide plate 324a of the lower unit 320 across the conveyance path. Similarly, the divided magnetic guide plate 314b and the divided magnetic guide plate 324b, The divided magnetic plate 314c and the divided magnetic plate 324c, and the divided magnetic plate 314d and the divided magnetic plate 324d face each other.

  As described above, by using a plurality of divided magnetic guide plates, the magnetic field strength between the upper unit 310 and the lower unit 320 can be changed in a stepped manner, and the allowable range of the MR sensor installation position deviation can be widened. Is possible.

  The upper unit 310 includes a yoke 311, a magnet 312, and a magnet 313 in a housing provided with a wear-resistant material on the conveyance path side. The divided magnetic guide plate 314 a is disposed on the conveyance path side of the magnet 312. Are provided with divided magnetic guide plates 314d on the conveying path side of the magnet 313, respectively. Further, between the magnet 312 and the magnet 313, there are divided magnetic guide plates 314b and divided magnetic guide plates 314c so as to be parallel to the divided magnetic guide plates 314a and 314d.

  The lower unit 320 has a yoke 321, a magnet 322, and a magnet 323 in a housing provided with a wear-resistant material on the conveyance path side. The divided magnetic guide plate 324 a is disposed on the conveyance path side of the magnet 322. Are provided with divided magnetic guide plates 324d on the conveying path side of the magnet 323, respectively. Further, between the magnet 322 and the magnet 323, there are divided magnetic guide plates 324b and divided magnetic guide plates 324c so as to be parallel to the divided magnetic guide plates 324a and 324d. A substrate 325 provided with an MR sensor (MR 1) 326 and an MR sensor (MR 2) 327 is provided near the upper surface in the lower unit 320.

  In the case of using a divided magnetic guide plate, it is allowed to install the divided magnetic guide plate in contact with each magnet, unlike the case of using a single magnetic guide plate.

  FIG. 9 is a diagram illustrating lines of magnetic force and magnetic field strength distribution generated by the magnetic quality detection device 300 according to the third embodiment. In addition, (A) in the figure shows the lines of magnetic force generated by the magnetic quality detection device 300, and (B) in the figure shows the magnetic field strength distribution.

  As shown in FIG. 9A, the magnet 312 of the upper unit 310 has an S pole on the conveyance path side and an N pole on the yoke 311 side, and the magnet 322 of the lower unit 320 has an N pole on the conveyance path side and a yoke 321. The side is the S pole. The magnet 313 of the upper unit 310 has an N pole on the conveyance path side and an S pole on the yoke 311 side, and the magnet 323 of the lower unit 320 has an S pole on the conveyance path side and an N pole on the yoke 321 side.

  In this way, each magnet unit (upper unit 310 and lower unit 320) is provided such that the magnets of the opposing magnet unit and the opposite poles face each other, so that each magnetic field line is opposed to the opposing upper unit 310 and lower unit. It becomes perpendicular to the conveyance line 501 at an intermediate point 320. Here, the transport line 501 indicates a position through which the transported paper sheet passes, and the direction of the arrow of the transport line 501 indicates the transport direction.

  That is, on the conveyance line 501 shown in the figure, the X-direction component of the magnetic field lines is 0 and only the Y-direction component, so that the paper sheets can be magnetized only in the Y direction. Therefore, it is possible to reliably control the magnetization of the subject (paper sheets) and improve the accuracy of coercive force detection.

  Here, the MR sensor (MR1) 326 is in a region between the divided magnetic guide plates 314b / divided magnetic guide plates 324b, and the MR sensor (MR2) 327 is in a region between the divided magnetic guide plates 314c / divided magnetic guide plates 324c. , Each is arranged. This is because the change in the magnetic field intensity becomes gentle in the region sandwiched between the opposed divided magnetic guide plates. This point will be described in more detail with reference to FIG.

  As shown in FIG. 9B, the magnetic field strength in the closed magnetic circuit formed by the upper unit 310 and the lower unit 320 is expressed as a curve 502 having no inflection point on the downstream side of the position 503. Further, in the vicinity of the position 504 and the position 505, the change in the magnetic field strength is stagnant (in a step shape).

  As described above, when the divided magnetic guide plates are used, the change of the magnetic field strength can be stagnated at the position corresponding to each divided magnetic guide plate. Therefore, it is possible to widen the allowable range of the installation position deviation of each MR sensor.

  For example, in the figure, an MR sensor (MR1) 326 is attached at a position 504, and acquires the magnetic field strength at a point 502b. However, even when the mounting position of the MR sensor (MR1) 326 is slightly shifted left and right in the figure, the magnetic field strength hardly changes. Therefore, even if the mounting position of the MR sensor (MR1) 326 is not accurately set to the position 504, it is possible to detect a magnetic field strength equivalent to that when the MR sensor (MR1) 326 is installed at the position 504.

  Also, in the same figure, the MR sensor (MR2) 327 is attached at a position 505 and acquires the magnetic field strength at the point 502c, but the mounting displacement of the MR sensor (MR2) 327 is also caused by the MR sensor (MR1) 326. It is allowed for the same reason as the case.

  By the way, when using a divided magnetic guide plate, the magnetic field strength distribution between the upper unit 310 and the lower unit 320 can be changed by shifting the position of the divided magnetic guide plate to the upstream side or the downstream side in the transport direction. Therefore, hereinafter, changes in the magnetic field strength distribution accompanying the movement of the divided magnetic guide plates will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a diagram illustrating a change in magnetic field strength distribution when the most upstream divided magnetic guide plate (the divided magnetic guide plate 314a and the divided magnetic guide plate 324a) is moved. In addition, the case shown in FIG. 10B is the default position, and in this case, the distance between each divided magnetic guide plate is 0.5 mm, 1.5 mm, and 0.5 mm from the left in FIG. .

  Here, as shown in the figure, a position adjusting mechanism 111 is attached to each of the divided magnetic guide plates 314a and the divided magnetic guide plates 324a. The position adjusting mechanism 111 is connected to, for example, a screw 111b, a fixed plate 111a that fixes the position of the screw 111b while allowing the screw 111b to rotate, and the divided magnetic guide plate 314a or the divided magnetic guide plate 324a. And a connecting member 111c that can change the relative distance from the fixed plate 111a by the rotation.

  Further, in (A) of the figure, the case where the distance between the divided magnetic guide plates 314a and 314b and the distance between the divided magnetic guide plates 324a and 324b is 1.0 mm is the same. (C) in the figure shows the same case of 0.2 mm, and (D) in the same figure shows the same case of 0.0 mm.

  And (E) of the same figure shows the curve which shows the change of the magnetic field intensity | strength corresponding to (A)-(D), respectively. Here, the curve 511 corresponds to (A), the curve 512 corresponds to (B), the curve 513 corresponds to (C), and the curve 514 corresponds to (D). In this way, the magnetic field strength distribution can be adjusted by changing the interval between the divided magnetic guide plates.

  FIG. 11 is a diagram showing a change in magnetic field strength distribution when the most downstream divided magnetic guide plate (the divided magnetic guide plate 314d and the divided magnetic guide plate 324d) is moved. In addition, the case shown in FIG. 11C is the default position, and in this case, the distance between each divided magnetic guide plate is 0.5 mm, 1.5 mm, and 0.5 mm from the left in FIG. . Note that the position adjusting mechanism 111 shown in FIG. 10 is connected to the divided magnetic guide plates 314d and 324d.

  Further, in (A) of the figure, the case where the distance between the divided magnetic guide plates 314c and 314d and the distance between the divided magnetic guide plates 324c and 324d is 0.0 mm is the same. (B) of the figure shows the case of 0.2 mm, and (D) of the figure shows the case of 1.0 mm.

  And (E) of the same figure shows the curve which shows the change of the magnetic field intensity | strength corresponding to (A)-(D), respectively. Here, the curve 521 corresponds to (A), the curve 522 corresponds to (B), the curve 523 corresponds to (C), and the curve 524 corresponds to (D). In this way, the magnetic field strength distribution can be adjusted by changing the interval between the divided magnetic guide plates.

  10 and 11 show the case where the most upstream and the most downstream divided magnetic guide plates are moved, respectively, it is also possible to move other divided magnetic guide plates. Further, the number adjusting mechanism for detachably fixing each divided magnetic guide plate may be used, and the number of the divided magnetic guide plates may be adjusted.

  By the way, although the case where each used the division | segmentation magnetic guide plate parallel to a conveyance direction was demonstrated until now, it is not necessary to make a division | segmentation magnetic guide plate parallel to a conveyance direction. FIG. 12 is a diagram showing a modified example of the arrangement of the divided magnetic guide plates. As shown in the figure, even if the divided magnetic guide plates are arranged so as not to be parallel to the conveyance direction, a conveyance line (see the arrow in the figure) in which each magnetic field line is parallel to the Y axis can be obtained.

  Further, the magnetic quality detection device 300 with the conveyance direction fixed has been described so far, but the magnetic quality detection device 300 corresponding to bidirectional conveyance may be configured. Therefore, hereinafter, the magnetic quality detection device 300 corresponding to the bidirectional conveyance will be described with reference to FIGS. 13 and 14.

  FIG. 13 is a diagram showing the configuration and magnetic field strength distribution of the magnetic quality detection apparatus 1 that supports bidirectional conveyance. In addition, (A) in the figure shows the lines of magnetic force generated by the magnetic quality detection device 300a, and (B) in the figure shows the magnetic field strength distribution.

  As shown in FIG. 13A, the magnetic quality detection device 300a has a shape in which the magnetic quality detection device 300 shown in FIG. 9 is connected to the position 542 shown in FIG. In addition, as shown to the figure, the magnetic quality detection apparatus 300a is comprised from the upper unit 310a and the lower unit 320a. Further, the transport line is located at the position of the double arrow shown in the figure, and the direction of each magnetic force line is parallel to the Y axis on the transport line.

  Further, as shown in FIG. 5B, the curve 544 showing the change in the magnetic field strength is represented as a non-decreasing graph having no inflection points in the section from position 541 to position 542. A curve 544 is represented as a non-increasing graph having no inflection points in the section from position 542 to position 543. Thus, since the magnetic quality detection apparatus 300a has a symmetrical shape with respect to the position 542, it can support bidirectional conveyance.

  In this case, when paper sheets are conveyed from left to right in the figure, the MR sensors “MR1” and “MR2” shown in the figure are used to convey the paper sheets from right to left in the figure. In this case, MR sensors “MR1 ′” and “MR2 ′” shown in FIG.

  FIG. 14 is a diagram showing the configuration and magnetic field strength distribution of the magnetic quality detection apparatus 2 that supports bidirectional conveyance. In addition, (A) in the figure shows the lines of magnetic force generated by the magnetic quality detection device 300b, and (B) in the figure shows the magnetic field strength distribution.

  As shown in FIG. 14A, the magnetic quality detection device 300b has a shape obtained by removing the wall at the central portion from the magnetic quality detection device 300a shown in FIG. As shown in the figure, the magnetic quality detection device 300a includes an upper unit 310b and a lower unit 320b. Moreover, a conveyance line becomes a position of the double arrow shown in the same figure, and the direction of each magnetic force line becomes parallel to a Y-axis on this conveyance line.

  Further, as shown in FIG. 5B, the curve 554 showing the change in the magnetic field strength is represented as a non-decreasing graph having no inflection points in the section from the position 551 to the position 552, and the position 552 to the position 553. In this section, it is expressed as a non-increasing graph with no inflection points. Thus, since the magnetic quality detection apparatus 300b has a symmetric shape with respect to the position 552, it can cope with bidirectional conveyance.

  In this case, when paper sheets are conveyed from left to right in the figure, the MR sensors “MR1” and “MR2” shown in the figure are used to convey the paper sheets from right to left in the figure. In this case, MR sensors “MR1 ′” and “MR2” shown in FIG.

  As described above, in the third embodiment, a plurality of divided magnetic guide plates are arranged on the conveyance path side of the upper unit, and a plurality of divided magnetic guide plates are arranged on the conveyance path side of the lower unit. / The change of the magnetic field strength between the lower units can be stepped. Therefore, it is possible to widen the allowable range of MR sensor mounting deviation. Further, the magnetic field strength distribution can be adjusted by changing the position of the divided magnetic guide plates or changing the number of the divided magnetic guide plates.

  Next, a case where a paper sheet pressing mechanism is added to the magnetic quality detection device 200 according to the second embodiment or the magnetic quality detection device 300 according to the third embodiment will be described with reference to FIG. FIG. 15 is a diagram showing a variation of the paper sheet pressing mechanism.

  Note that (A) in the figure shows the paper sheet pressing mechanism added to the magnetic quality detection apparatus 300 according to the third embodiment, and (B) in the same figure and (C) in the same figure show the paper sheet holding mechanism. The paper sheet holding mechanism added to the magnetic quality detection apparatus 200 according to Example 2 is shown. Also shown in the drawing are a paper sheet 500, a transport direction 501 of the paper sheet 500, and a wear resistant plate 502 made of a wear resistant material provided on the upper surface (conveying path side) of the lower unit 320 or the lower unit 220. Show.

  As shown in FIG. 15A, in the case of the magnetic quality detection device 300 according to the third embodiment, the distance between the upper unit 310 and the lower unit 320 is larger than that of the magnetic quality detection device 200 according to the second embodiment. Need to be narrow. This is because a magnetic field inflection point exists at an intermediate position between the upper unit 310 and the lower unit 320, and therefore, the transport position of the paper sheet 500 needs to be near the magnetic field inflection point position.

  As described above, in the magnetic quality detection device 300 according to the third embodiment, the interval between the upper unit 310 and the lower unit 320 is small. Therefore, as shown in FIG.

  Specifically, the pressing spring 71 is fixed by a pin 72 and presses the conveyed paper sheet 500 against the upper surface of the lower unit 220. However, pressing with a leaf spring such as the pressing spring 71 tends to cause jam (paper jam) during high-speed conveyance of paper sheets.

  Therefore, as shown in FIGS. 15B and 15C, if the magnetic quality detection device 200 according to the second embodiment is used, the magnetic field inflection point position is adjusted near the upper surface of the lower unit. Therefore, the distance between the upper unit 210 and the lower unit 220 can be increased. Thereby, the arm with a roller with a high pressing effect with respect to the paper sheet 500 can be used as a paper sheet pressing mechanism.

  As shown in FIG. 3B, the arm with roller is configured by attaching a roller 75 to the arm 73. Specifically, the arm 73 that supports the roller 75 with the roller shaft 76 is attached so as to rotate around the arm shaft 74, and one end of the arm 73 is fixed to the pin 77 via the spring 78. .

  When such an arm with a roller is used, the arm with a roller may move to a position indicated by a broken line in the figure (see 73a in the figure). Therefore, as shown in FIG. 5B, the upper unit 210 needs to be provided at a position where it does not contact the arm with roller. For this reason, as shown in (B) of the same figure, it is necessary to make the space | interval between the upper unit 210 / lower unit 220 larger than the case shown to (A) of the same figure.

  Therefore, as shown in FIG. 15C, the lower surface of the upper unit 210 is recessed on the lower side so as to avoid contact with the arm with rollers, and the mounting position of the upper unit 210 is changed to the position shown in FIG. The mounting position of the upper unit 210 in B) may be closer to the conveyance path side than the attachment position (see 79 in the figure). By doing in this way, the apparatus size of the magnetic quality detection apparatus 200 can be made compact, using an arm with a roller.

  As described above, the magnetic quality detection device according to the present invention is useful when it is desired to accurately detect the difference in coercive force characteristics of magnetic ink.

Claims (6)

A magnetic quality detection device for detecting the magnetism of the paper sheet by transporting the paper sheet printed with magnetic ink along the transport surface,
Magnet units in which different poles of magnets are connected by a yoke are arranged at positions facing each other across the transport surface, and the direction of a magnetic vector is perpendicular to the transport surface in a magnetic detection section on the transport surface. And the magnetic field generating means adjusted so that the magnetic field intensity in the transport direction in the magnetic detection section is monotonously increased, monotonically decreased, or monotonically decreased after the monotonic increase ,
A magnetic quality detection device comprising: a magnetic quality detection means provided in the magnetic detection section. Each magnet unit of the magnetic field generating means is
The magnetic quality detection device according to claim 1, wherein the magnetic poles of the magnets facing each other across the transport surface are arranged so as to be different from each other. The magnetic field generating means includes
It further comprises a plurality of divided magnetic guide plates divided in the transport direction on the transport surface side of each magnet unit,
The magnetic quality detection means includes
The magnetic quality detection apparatus according to claim 1, wherein the magnetic quality detection apparatus is provided at a position corresponding to the divided magnetic guide plate and closer to the transport surface than the divided magnetic guide plate. The magnetic field generating means includes
The magnetic quality detection apparatus according to claim 3, further comprising a position adjustment mechanism that adjusts a position of the divided magnetic guide plate in a conveyance direction. The magnetic field generating means includes
One magnetic guide plate is further provided on the transport surface side of one of the magnet units,
The magnetic quality detection means includes
The magnetic quality detection device according to claim 1, wherein the magnetic quality detection device is provided closer to the conveyance surface than the magnetic conducting plate. The magnetic field generating means includes
The magnetic quality detection apparatus according to claim 5, wherein a distance between the transport surface and the one magnet unit is adjusted by using the magnetic guide plates having different magnetic conductivities and / or plate thicknesses.

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