WO2020149375A1

WO2020149375A1 - Magnetic identification sensor

Info

Publication number: WO2020149375A1
Application number: PCT/JP2020/001353
Authority: WO
Inventors: 川瀬　正博; 裕貴関河; 匠佐藤
Original assignee: キヤノン電子株式会社
Priority date: 2019-01-17
Filing date: 2020-01-16
Publication date: 2020-07-23
Also published as: JP7008149B2; JPWO2020149375A1; CN113302693B; CN113302693A

Abstract

The present invention makes it possible to increase an applied magnetic field on a sliding surface side of a magnetic identification sensor, thereby increasing an output of the sensor and stabilizing waveforms. Provided is a magnetic identification sensor in which magnets and a magnetic detection element are integrated at a lower part of a sliding surface which comes into contact with a medium being conveyed, and which determines a magnetic pattern of a magnetic material part within the medium, said magnetic identification sensor being characterized in that: a substantially U-shaped (horseshoe-shaped) magnetizing part is formed by disposing a pair of rectangular parallelepiped magnets, the N-S direction of which is perpendicular to the sliding surface, at a predetermined interval in a medium conveyance direction in parallel such that the polarities are opposite to each other, and by having the magnetic pole on one side of each of the magnets arranged close to the lower part of the sliding surface, and having the magnetic poles on a side opposite to the sliding surface coupled to each other by an iron-based yoke member; the magnetic detection element, a magnetic field detecting direction of which is a direction perpendicular to the sliding surface, is arranged in a space within the magnetizing part; and the magnetic pattern of the medium, which has been magnetized in the medium conveyance direction as a result of passing over the pair of magnets above the sliding surface, is read by the magnetic detection element.

Description

Magnetic identification sensor

The present invention is a magnetic identification sensor for performing magnetic type detection or magnetic type detection on a paper-shaped medium incorporating a magnetic ink containing a magnetic material such as a bill or a magnetic foil strip, and performing type determination or authenticity determination, and It relates to the device.

Conventionally, in the identification of banknotes, the printed magnetic ink is magnetized by the magnetic field of the magnet in the magnetic sensor, and the change of the magnetic field related to the printing pattern of the magnetic ink is magnetically detected by the magnetic detection element, thereby discriminating the type of banknote and authenticity. Judging.

There are two types of magnetic materials used for media, so-called hard magnetism, which has a large coercive force, and so-called soft magnetism, which has almost no coercive force. In particular, in order to deal with the detection of the soft magnetic material by the magnetic sensor, it is necessary to detect the magnetization of the soft magnetic material while the magnetic field is applied to the soft magnetic material by the magnet arranged on the sensor side.

Since semiconductor magnetic resistance element (SMR) does not have magnetic saturation, a magnet can be installed directly under the element and there is no restriction on the magnet. However, most of the other sensors have magnetic saturation related to the magnetic substance, and the installation of the magnet is devised within the restriction on the operating point.

JP, 2007-286012, A Patent No. 6209674

For example, in a magnetic impedance element or a fluxgate sensor having a narrow operating point, as shown in Patent Document 1, magnets of opposite polarities are placed in front of and behind the magnetic detection element, and a magnetic field in a direction orthogonal to the magnetic sensitive direction of the magnetic detection element. It is shown that the magnetic field applied to the element is relaxed by strengthening the magnetic field.

Further, even in a magnetoresistive (MR) element such as an anisotropic magnetoresistive element (AMR) or a tunnel magnetoresistive element (TMR) in which magnetic saturation is present, magnets having opposite polarities before and after the element as described in Patent Document 2. Is set so that it does not affect the operating point.

However, although the arrangement of the magnets has been devised, there is a difference in the magnetic field distribution on the sliding surface side depending on the arrangement of the magnets, and the sensitivity is lowered due to the floating on the sliding surface against the conveyance of the medium, so-called spacing loss. Occurs. From the viewpoint of improving performance, there is an increasing demand for reducing the loss.

Also, in the medium circumstance, in recent years, a medium with a high coercive force whose coercive force greatly exceeds 1 kOe (Oersted) has appeared, and it is necessary to increase the magnetic force of the incorporated magnet. In order to increase the magnetic force of the magnet, there are adverse effects such as restriction on the size and generation of pseudo output (noise) due to relative displacement of the magnet and the magnetic detection element against vibration and stress.

In view of the above, the magnetic identification sensor according to the present invention,
A magnetic identification sensor in which a magnet and a magnetic detection element are arranged below a sliding surface that is in contact with a medium to be conveyed, and which determines a magnetic pattern of a magnetic body part included in the medium,
A pair of magnets having an NS direction perpendicular to the sliding surface has a magnetic pole on one side of each of the magnets at a predetermined interval in the medium transport direction so that the magnets have opposite polarities, and a magnetic pole on one side of the magnet is below the sliding surface. Are juxtaposed close to
A magnetized portion in which magnetic poles on the other side of the magnet are connected by a yoke is formed,
In the magnetizing part, the magnetic detection element having a magnetic field detection direction perpendicular to the sliding surface is arranged in a space surrounded by a pair of the magnet and the yoke on three sides. To do.

According to the present invention, in the one in which the direction of the magnetic field generated on the sliding surface is defined by using a pair of magnets, by providing the yoke, the magnetic field for magnetizing the medium on the sliding surface is increased, Further, it is possible to provide a magnetic discrimination sensor in which the structure of the sensor unit including the magnetic detection element and the magnet is strengthened to suppress the influence of pseudo output (noise) due to vibration or stress.

The block diagram of the magnetic identification sensor which concerns on embodiment of this invention. Sectional drawing of the magnetic identification sensor which concerns on embodiment of this invention. The block diagram of the magnetic detection element which concerns on embodiment of this invention. 1 is an external perspective view of a magnetic identification sensor according to an embodiment of the present invention. Explanatory drawing of NS direction of a magnet, a yoke, and attachment. The graph which shows the relationship between the distance from the sliding surface of a sensor, and magnetization. An example of the external magnetic field characteristic of a magneto-impedance element. An example of the output of the magnetic detection element when the yoke is attached. The graph of the output by the floating amount of the magnetic medium from the sliding surface. The block diagram of the magnetic identification sensor which concerns on other embodiment of this invention. Sectional drawing of the magnetic identification sensor which concerns on other embodiment of this invention.

The present invention will be described in detail based on the illustrated embodiment. FIG. 1 is a configuration example of a magnetic identification sensor to which the identification processing of the present case is applied, and is an external perspective view showing a positional relationship between a paper-shaped magnetic medium to be detected, a magnet constituting the sensor, and a magnetic detection element. A bill is mentioned as an example of a paper-like magnetic medium. The magnetic discriminating sensor of the present invention moves the magnetic medium relative to the magnetic detecting element, and detects the magnetic pattern generated by the magnet due to the magnetic material portion of the magnetic medium or the change in the magnetic pattern, which is caused by the magnetic detecting element. By doing so, the sensor discriminates the magnetic medium. For the sake of explanation, the sliding member 5 is shown transparently.

The magnetic detection element 1 and the

magnets

2a and 2b are incorporated in the sensor body 4, and are arranged below the sliding surface 6 of the sliding member 5 along the medium transport direction indicated by the arrow. In the following description, the

magnets

2a and 2b may be collectively referred to as the magnet 2.

First, the structure of the magnet will be explained. The

magnets

2a and 2b have a rectangular parallelepiped structure and are cut out from a block material. Basically, it is preferable to use parts having the same shape in order to make the magnetic field distribution symmetrical.

As a material for the

magnets

2a and 2b, a Nd-Fe-B or Sm-Co based rare earth magnet is suitable because it requires a magnetic field of at least several hundred Gauss on the sliding surface 6.

In order to set the NS direction of the

magnets

2a and 2b in the direction perpendicular to the sliding surface 6, the material is taken so that the perpendicular direction is the magnetization direction with respect to the surface of the rectangular parallelepiped magnet which is close to the lower part of the sliding surface 6.

As shown in FIG. 1, two

magnets

2a and 2b are arranged as a pair of magnets in parallel at a predetermined distance d in the medium transport direction. The pair of magnets are arranged so that their polarities are opposite to each other. Therefore, the magnetic poles on one side of the

magnets

2a and 2b are arranged in close proximity to the lower part of the sliding surface 6.

Further, the iron-based yoke 3 is arranged so as to bridge and connect between the magnetic poles opposite to the sliding surface 6 (between the magnetic poles on the other side). By closing the magnetic flux between the magnetic poles of one of the pair of magnets in the yoke 3, a U-shaped (in other words, horseshoe-shaped) magnet body M is formed, and a magnetized portion as a sensor is formed. The requirement for the yoke 3 is that the saturation magnetic flux density is high, and the magnetic permeability itself is not so important. Iron-based steel sheets having a saturation magnetic flux density of more than 2 T (tesla) are preferable because they are inexpensive and easily available.

As will be described later, the magnetic effect of the yoke 3 is that the magnetic field on the sliding surface 6 side can be almost doubled and the magnetic force for magnetizing the medium can be increased. The yoke 3 may have a flat plate shape (flat plate shape) as long as at least the surfaces on which the magnets are seated are on the same plane. As described above, by preventing a gap from being formed between the magnet 2 and the yoke 3, it is possible to prevent a magnetic pole from being generated between the magnet and the yoke 3, and to simplify the magnet body M as an integral magnetizing portion. Can be formed. Further, the

magnets

2a and 2b and the magnetic detection element 1 can be attached with the yoke 3 as a reference. That is, by ensuring the flatness of the yoke 3, a desired magnetic field can be stably formed, and the detection accuracy can be improved.

Further, the yoke 3 plays a role of the spine of the sensor part, and determines the rigidity of the sensor part. Considering the stress deformation at the time of assembling and the flexural strength at the time of transporting the medium, the plate thickness of 0.5 mm or more. Is preferably secured. Further, since the magnet and the magnet have an attraction force relationship, the structure of the magnet body is extremely stable, and the pseudo output due to the relative displacement of the magnet is rarely generated.

The magnetic detection element 1 is installed in the U-shaped inner space of the magnet body M in the lower part of the sliding surface 6, that is, in the space surrounded by the pair of magnets 2 and the yoke 3 on three sides. Magnetization is detected when the magnetic printing unit 9 of the above passes directly above. At this time, the magnetic field detection direction of the magnetic detection element 1 is arranged so as to be perpendicular to the sliding surface 6. When a large bias magnetic field is applied, the high-sensitivity magnetic detection element is magnetically saturated and does not operate. Therefore, the high-sensitivity magnetic detection element is basically installed at the position of the zero magnetic field which is approximately the midpoint of the

magnets

2a and 2b. Even for a magnetic detection element that requires a bias magnetic field, it is possible to secure the required bias magnetic field (about several to several tens Oe) by slightly shifting it from the position. Although the magnetic detection element 1 is installed in a space surrounded by three sides, it does not need to be separated from the yoke 3 and the magnet 2 that form the space, and is disposed in contact with the yoke 3 and the magnet 2. Is also good.

FIG. 2 shows a cross-sectional view of this embodiment, and the axis of symmetry of the pair of magnets is indicated by the Z-axis, but the elements are arranged so as to have magnetic field detection sensitivity in the axial direction. The sensing surface (magnetically sensitive surface) of the element is the YZ plane.

On the sliding surface 6 side, a fairly strong magnetic field is applied in the X direction due to the magnetic flux Φp generated between the two

magnets

2a and 2b, but in the Z direction, the magnetic field is orthogonal to the magnetic field and the zero magnetic field environment is generated. can get.

Also, this means that an unnecessary magnetic field is applied to the magnetic detection element if the magnet or element is slightly tilted, so the processing accuracy of the magnet and the flatness of the yoke are important. In the configuration of the present case, it is easy to secure the accuracy of parts such as the perpendicularity of the magnet and the flatness of the yoke, and there is little concern about the assembly accuracy.

As shown in FIG. 3( a ), the magnetic detection element 1 is composed of a rectangular parallelepiped non-magnetic substrate 11, and a pattern of a magnetic thin film 12 composed of a plurality of long thin parallel lines is formed on one surface thereof. As the magnetic thin film, permalloy, Fe-Co-Si-B based amorphous, Fe-Ta-C based microcrystalline thin film or the like is used. In the present embodiment, the magnetic thin film 12 has a pattern extending on the non-magnetic substrate 11 in the Z direction.

The magnetic thin film 12 has a magnetic detection direction in the longitudinal direction and faces the Z direction. This direction is the same as the NS direction of the adjacent magnet 2.

The magnetic detection element 1 shown in FIG. 3A is a type of magneto-impedance element, in which each pattern of the magnetic thin film 12 is connected in series by the conductive film 13, and a high frequency drive in the MHz band is performed between the electrode parts 14. A current is applied (energized), and a change in impedance with respect to an external magnetic field is extracted as a sensor signal voltage.

In another method, the sensor signal is not directly taken out from the magnetic film as shown in FIG. 3B, but the coil 15 is laminated or wound externally to perform a fluxgate operation, and a change in induction output from the detection electrode 16 is generated. The output can be taken out and operated as a so-called orthogonal fluxgate sensor.

Since the magneto-impedance element exhibits a V-shaped external magnetic field characteristic as shown in FIG. 3C and has no sensitivity at zero magnetic field, a bias magnetic field to the inclined portion is required. An offset magnetic field is given by slightly shifting the position in the X-axis direction.

In the case of the orthogonal fluxgate sensor, as shown in Fig. 3(d), there is no magnetic field and there is no inclination, so bias is unnecessary and offset processing is also unnecessary. The technology of the present invention can be used as long as it is a sensor that can form a pattern on one surface of other magnetoresistive elements and have magnetic field detection sensitivity in the NS direction of the magnet. In this case, by arranging the sensor so that the magnetically sensitive surface of the sensor is located at the zero point of the magnetic field generated by the magnet 2, the magnetic field generated by the magnetic medium can be effectively detected.

Specifically, anisotropic magnetoresistive element (AMR), tunneling magnetoresistive element (TMR), and giant magnetoresistive element (GMR) are also candidates.

A combination of the

rectangular parallelepiped magnets

2a and 2b and the flat yoke 3 can form a magnet body M that is strong against vibrations and stresses caused by medium conveyance. On the other hand, it is preferable to maintain the interval and prevent the falling.

As shown in FIG. 2, when the spacing member 10 is inserted between the surface of the element opposite to the detection surface and one of the magnets (magnet 2b) facing the surface, a pseudo output due to relative position fluctuation is generated. Is reduced, and it is easier to guarantee accuracy when incorporating. If the non-magnetic substrate 11 of the magnetic detection element 1 can be made thick and the gap with the magnet 2b can be eliminated, the gap holding member 10 can be omitted and the non-magnetic substrate 11 and the magnet 2b can be directly bonded. You may join and fix with.

Further, the magnetic detection element 1 is brought into contact with the yoke 3 so that the height hs of the magnetic detection element 1 is set to be equal to or lower than the height hm of the magnet, and an external force is applied downward from the sliding surface 6 (negative Z-axis direction). Even if it is exerted, it is preferable that the magnetic detection element 1 is not loaded.

As described above, the present invention connects the two magnets with the yoke, increases the magnetic force of the magnet, and establishes the detection unit of the small and high-strength magnetic identification sensor with the yoke as the backbone.

Next, the effectiveness of this embodiment will be explained based on the results of trial production. FIG. 4 shows an external perspective view of the prototype sensor. However, for the sake of explanation, the sliding member 5 is shown transparently. The same functions as those in FIG. 1 are denoted by the same reference numerals.

The magnet 2 is a rectangular parallelepiped measuring 1.5×1.2×21 mm, cut out from a magnet block of Nd-Fe-B (Br1.12T), and the surface of 1.5×21 mm is in contact with the sliding surface, and its vertical direction. Is in the NS direction. The distance d between the pair of magnets is basically set to 2.6 mm, and the bias is adjusted finely at this distance. For the yoke 3, a SPCC material, which is a general steel plate, having a thickness of 0.8 mm was selected. The saturation magnetic flux density is 2.04T.

Here, the verification results of selecting the magnet NS direction and attaching the yoke will be described. As shown in FIG. 5, the configuration of FIG. 4 was modeled and the magnetic fields generated on the sliding surface side were compared by calculation. When (a) is the structure of FIG. 4 without a yoke, (b) is the layout of (a), and the NS direction of the magnet 2 is horizontal, (c) is the structure itself. The respective results are shown in FIG.

First, comparing (a) and (b), which relate to the NS direction of the magnet without a yoke, the NS horizontal direction (b) is clearly worse than the distance from the sliding surface. In the case (a) in which the NS direction is perpendicular to the sliding surface 6, the distance from the sliding surface 6 increases slightly even if the distance from the sliding surface 6 increases, and the magnetic poles are preferably outward.

Furthermore, when a yoke is added to the configuration of (a), the magnetic force is increased by about 1.8 times, and there is a slight attenuation, but it is good. Even if the size and material of the magnet are not changed, the effect of closing the side opposite to the sliding surface with the yoke is great. In the soft magnetic medium, the larger the applied magnetic field, the stronger the magnetization, and the increase in the sensor output can be expected.

In terms of productivity as well, in (a), the positional relationship between the four magnetic poles of the left and right magnets affects the detection result, so not only the distance between the magnets, but also the parallelism (tilt) of the left and right magnets in the NS direction It will greatly affect the variation. In (c) with a yoke, the magnetic poles are basically treated as two surfaces of the

magnets

2a and 2b on the sliding surface 6 side, and it becomes easy to secure the bias of the magnetic detection element 1.

The magnetic detection element 1 is constructed on a ceramic non-magnetic substrate 11 having a thickness of 0.75 mm so that the surface on which the magnetic thin film 12 is formed is 1.15×21 mm.

The magnetic thin film 12 has a thickness of 2.6 μm, a pattern width of 18 μm, and a length of 0.5 mm, which are arranged at equal intervals, and are divided into four parts so that they can function as 4 channels in a multi-channel, and each electrode part 14 is provided.

A non-magnetic spacing member 10 that regulates the spacing between the magnetic detection element 1 and the magnet 2b was sandwiched on the back surface of the element, and the yoke 3 and the magnet 2b were fixed with an adhesive. The thickness of the spacing member 10 was 0.5 mm.

The magnetic detection element 1 in this example operates as a magnetic impedance element, applies a pulse current in the MHz band, and extracts the amplitude change with respect to the external magnetic field by the AM detection circuit.

As shown in FIG. 7, the magneto-impedance element has an external magnetic field characteristic that requires a bias magnetic field with respect to the magnetic thin film portion, and when the magnetic medium 8 is not detected, the output is located in the area A or B. set. The adjustment can be easily performed by finely adjusting the distance to the magnet 2a on the side to which the distance maintaining member 10 is not adhered. This time, in order to select the region B and perform the shift adjustment of about 20 [Oe], it is dealt with by slightly shifting it from the center of the pair of magnets by about several tens of μm (region of 40 [Oe] or less). On the other hand, when a flux gate element is used as the magnetic detection element 1, since it can be operated at the center of the pair of magnets, it may be set at a position where the output becomes the zero point. In this way, by arranging the magnetic thin film of the magnetic detection element 1 near the zero point of the magnetic field generated by the pair of magnets, the magnetic detection element 1 is suitable for use with either a magnetic impedance element or a fluxgate element. Can be operated.

From the electrode portion 14 of the magnetic detection element 1, a flexible cable was pulled out to a lower circuit board from a through hole (not shown) provided in the yoke 3. Unless a large hole is drilled, the magnetic flux wraps around in the yoke 3 and its effect hardly appears.

Next, as a test medium for the magnetic medium 8, a medium having the magnetic printing unit 9 shown in FIG. 4 was transported, and the decrease in output with respect to the floating amount on the sliding surface 6 was evaluated. In the evaluation of the floating amount, adjustment was performed by sandwiching 0.1 mm paper one by one. The magnetic printing unit 9 is a 3 mm-wide printed long and narrow line with soft magnetic ink.

Fig. 8 shows an example of the output voltage measurement results. This waveform is measured in a state where the sliding surface 6 and the magnetic medium 8 are in close contact with each other and the floating amount is zero. The magnetic printing unit 9 is magnetized in the transport direction and has a differential waveform when detecting a magnetic field in the Z direction, and expresses an output value as a peak-to-peak value.

The solid line c in FIG. 8 is the output waveform when the yoke 3 of the present case is provided, and the broken line a in FIG. 8 is the output waveform data when the measurement is performed by replacing the iron-based yoke material with a non-magnetic metal material of phosphor bronze. Is.

In the case of a soft magnetic material, the magnetization also increases in accordance with the applied magnetic field, so the magnetic field on the sliding surface is approximately 1.8 times larger in the case of the solid line c than in the case of the broken line a, so the output The voltage increased about 1.7 times.

FIG. 9 is a graph showing the output change with respect to the floating amount of the medium. Prototype data in the case where the NS direction of the magnet is horizontal is also shown so that the data corresponding to (a), (b), and (c) of FIG. 6 can be compared.

In (b), in which the NS direction of the magnet is oriented horizontally to the sliding surface 6, the magnetic field is greatly attenuated, and therefore the output is significantly reduced with respect to the floating amount of the medium. In the arrangement (a) in which the NS direction is oriented perpendicular to the sliding surface 6, the decrease in the output with respect to the floating amount of the medium is small. Further, in the present embodiment (c) in which the yoke 3 is provided, the overall output is increased, and the decrease in output with respect to the floating amount of the medium is further reduced.

The reason why the attenuation in (c) where the yoke 3 is provided is slightly better than that in (a) is that the output is slightly saturated when a sufficient magnetic field is applied as a characteristic of the soft magnetic medium. is there.

Further, the form shown in FIG. 4 shows that it can be applied as a multi-channel sensor used in ATMs of banks, and it is easy to connect and arrange a plurality of sensors, and the detection width of the magnetic medium 8 can be freely set. The degree is also high.

Further, since the magnetic detection element 1 and the

magnets

2a and 2b are directly assembled to the yoke 3, and the yoke 3 can be treated as a backbone of the structure of the magnetic identification sensor, the entire sensor portion can be thinned while ensuring strength.

By increasing the strength of the sensor by the yoke 3, it is possible to suppress the effect of pseudo output on vibration and stress to a level that can be ignored even if the magnetic force of the magnet is increased. In other words, a small and thin sensor can be realized in other words.

Another embodiment of the present invention will be described with reference to FIG.
Since the magnet and the magnetic detection element have a length that is easy to handle, it is preferable to connect and use a plurality of sensor units 31 to 34 for a wide range of detection applications such as bills. That is, it becomes as shown in FIG. 10 in which a plurality of sensor unit parts of the embodiment shown in FIG. 4 are connected.

Further, in this embodiment, the magnetic detection elements 21 are provided in pairs of a magnetic thin film row F22 near the sliding portion and a magnetic thin film row R23 apart from the sliding portion, and the detection portions are arranged on the same non-magnetic substrate. However, it is configured to operate differentially. With this element configuration, it is possible to detect only the component with a large magnetic gradient from the sliding surface side due to medium transport, and to significantly remove the surrounding disturbing magnetic field, for example, a nearby bearing in the transport mechanism. It is possible to reduce the magnetic effect on the shaft and shaft.

However, in this configuration, the magnetic detection element 21, the magnet 2 and the end of the yoke 3 overlap on the connection side of the sensor unit end with respect to the y direction in FIG. 10, and the magnetic field is likely to be disturbed due to discontinuity with the adjacent unit, resulting in magnetic detection. It adversely affects the operating point of the device.

Therefore, it may be necessary to appropriately correct the disturbed magnetic field so that the magnetic field that does not require bias is zero magnetic field, and the magnetic field that requires bias is within the predetermined bias range.

When the magnetic field is corrected, as shown by magnetic

thin plates

24a and 24b in FIG. 10, a thin plate of a magnetic metal such as a silicon steel plate or permalloy that can be magnetized is formed into a disc or a strip-shaped small piece, and the side surface of the magnet is formed. It can be easily modified by adding to.

Explanation will be given using a sectional view of the sensor unit shown in FIG. By applying a magnetic thin plate 24 of a magnetic material to the side surface of the magnet 2, it is magnetized, and a local bias magnetic field can be applied from the magnetized magnetic thin plate 24 to the magnetic detection element 21. The bias can be adjusted by magnetizing the magnetic body using the magnetic field of the magnet of the sensor without the need to prepare a magnet for correction, and because the magnet 2 and the magnetic thin plate 24 are attracted to each other, It is easy to handle. The magnitude of the bias magnetic field to be corrected can be adjusted by the shape, thickness or number of the magnetic thin plates 24.

This bias magnetic field can be corrected not only at the end of the unit like the magnetic thin plate 24a in FIG. 10 but also at the center of the unit like the magnetic thin plate 24b. It is also effective for the correction of edge variations, etc.) and edge chipping.

The present invention has a feature that the sensor unit can be unitized and can freely deal with the detection width of various media.

The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, it has been described that the parts having the same shape as the

magnets

2a and 2b are preferable, but the present invention is not limited to this, and for example, the magnet 2a having a larger size is used, thereby biasing the magnetic detection element 1. A magnetic field may be formed.

1, 21

Magnetic detection elements

2a, 2b Magnet 3 Yoke 4 Sensor body 5 Sliding member 6 Sliding surface 7 Terminal 8 Magnetic medium 9 Magnetic printing unit 10 Interval holding member 11 Non-magnetic substrate 12 Magnetic thin film 13 Conductive film 14 Electrode unit 15 Thin film coil 16 Detection electrode 17

Circuit boards

22, 23 Magnetic

thin film rows

24, 24a, 24b Magnetic thin plates 31-34 Sensor unit

Claims

A magnetic identification sensor in which a magnet and a magnetic detection element are arranged below a sliding surface that is in contact with a medium to be conveyed, and which determines a magnetic pattern of a magnetic body part included in the medium,
A pair of magnets having an NS direction perpendicular to the sliding surface has a magnetic pole on one side of each of the magnets at a predetermined interval in the medium transport direction so that the magnets have opposite polarities, and a magnetic pole on one side of the magnet is below the sliding surface. Are juxtaposed close to
A magnetized portion in which magnetic poles on the other side of the magnet are connected by a yoke is formed,
In the magnetizing part, the magnetic detection element having a magnetic field detection direction perpendicular to the sliding surface is arranged in a space surrounded by a pair of the magnet and the yoke on three sides. Magnetic identification sensor.
The magnetic discrimination sensor according to claim 1, wherein the pair of magnets have the same shape, and the surfaces of the yokes that contact the magnetic poles on the other side of the pair of magnets are located on the same plane.
The yoke has a flat plate shape, the magnetic detection element is fixed to the yoke, and the magnetic thin film of the magnetic detection element is arranged near a zero point of a magnetic field generated by the pair of magnets. The magnetic identification sensor according to claim 1 or 2.
The magnetic identification sensor according to any one of claims 1 to 3, wherein the magnetic detection element is arranged at a midpoint of the pair of magnets.
The magnetic detection element is arranged between the pair of magnets in the medium transport direction, has a rectangular parallelepiped non-magnetic substrate, and has on one surface thereof a plurality of magnetic members extending parallel to the NS direction of the magnets. The magnetic discrimination sensor according to claim 1, wherein a thin film is formed, and a drive current is applied to the magnetic thin films connected in series.
A high-frequency current is applied as the drive current to the magnetic thin film of the magnetic detection element, and a change in impedance thereof is directly detected, or a coil is laminated or wound around the magnetic thin film to perform a fluxgate operation. The magnetic identification sensor according to claim 5.
A non-magnetic spacing member that regulates a spacing is disposed between a surface of the magnetic detection element opposite to the detection surface and the magnet facing the opposite surface. The magnetic identification sensor according to claim 1.
7. The surface of the magnetic detection element opposite to the detection surface and the magnet facing the opposite surface are directly bonded to each other, according to any one of claims 1 to 6. Magnetic identification sensor.
9. The magnetic identification sensor according to claim 1, wherein the magnetic thin films of the magnetic detection element are arranged in two rows on the side closer to the sliding surface and on the side farther from the sliding surface to perform a differential operation. ..
The magnetic identification sensor according to any one of claims 1 to 9, further comprising a plate-shaped magnetic field adjusting magnetic body on a side surface of the magnet.