JP2008081303A - Paper sheet detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet detector and a paper sheet detecting method, detecting a skew angle and sliding amount of a paper sheet with high accuracy. <P>SOLUTION: This paper sheet detector 1 includes first and second sensors 4, 7 spaced from each other along the carrying direction T. The distance from a first detecting point 8 for detecting passing of the paper sheet M by the first sensor 4 and a second detecting point 9 for detecting passing of the paper sheet M by the second sensor 7 is set to non-integer multiples of the distance of the paper sheet M carried at intervals of a sampling period for sampling the sensor output by an operating part 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper sheet detection apparatus that detects skew or slide of a paper sheet being conveyed.

  2. Description of the Related Art Conventionally, as a device for detecting the conveyance posture of paper sheets, a skew having two sets of line sensors that are separated from each other along the conveyance path and extend in a direction crossing the conveyance path from the inner wall facing the conveyance path toward the conveyance center. A detection device is known (for example, refer to Patent Document 1). The two sets of line sensors are provided symmetrically with respect to the conveyance center, and detect the position of the edge of the paper sheet at two positions along the conveyance direction of the paper sheet to be conveyed. As a result, the skew and slide (shift in the width direction from the conveyance center) of the paper sheet are detected.

However, in the above-described conventional skew detection device, since the detection resolution is determined according to the time interval for sampling the sensor output and the conveyance speed of the paper sheet, it is difficult to detect the skew and slide of the paper sheet with high accuracy. I was unable to detect a satisfactory posture. That is, when the signal sampling interval is longer than the sheet transport speed, the detection resolution is lowered. In particular, in an apparatus that discriminates the denomination or authenticity of a banknote after posture detection, it is necessary to detect skew and slide with high accuracy.
JP-A-2-249837

  An object of the present invention is to provide a paper sheet detection apparatus capable of detecting a skew angle and a slide amount of a paper sheet with high accuracy.

  In order to achieve the above object, a paper sheet detection apparatus according to the present invention detects a presence or absence of a paper sheet at a plurality of first detection points spaced apart from each other in a width direction substantially orthogonal to the paper sheet conveyance direction. A sensor, a second sensor for detecting the presence or absence of paper sheets at a plurality of second detection points spaced in the transport direction with respect to each of the plurality of first detection points, and all of the first and second sensors. A posture detection unit that samples the sensor output at the detection point at a constant period and detects the conveyance posture of the paper sheet to be conveyed based on the sensor output for a plurality of periods; The distance along the conveyance direction between the second detection points is set to a distance that is a non-integer multiple of the distance that the paper sheet is conveyed at each sampling period.

  According to the above invention, the first sensor having a plurality of first detection points spaced apart from each other in the width direction substantially orthogonal to the paper sheet conveyance direction, and a plurality of the first detection points separated in the conveyance direction from each of the first detection points. Using a second sensor having a second detection point, paper sheets are detected at a constant sampling cycle, and the distance between each first detection point and the corresponding second detection point is a non-integer of the sampling cycle. Since it is doubled, the first detection point and the second detection point do not overlap on the paper sheet, the number of detection signal samplings can be increased without changing the sampling period, and the detection accuracy can be increased.

  According to another aspect of the present invention, there is provided a paper sheet detection device that detects the presence or absence of a paper sheet at a plurality of first detection points spaced apart from each other in a width direction substantially orthogonal to the paper sheet conveyance direction, A second sensor for detecting the presence or absence of paper sheets at a plurality of second detection points spaced in the transport direction with respect to each of the first detection points, and sensor outputs at all detection points of the first and second sensors. And calculating a skew angle of the conveyed paper sheet based on the sensor output for a plurality of periods, and between the first and second detection points. The distance along the transport direction is set to a distance that is a non-integer multiple of the distance at which the paper sheet is transported for each sampling period.

  Since the paper sheet detection apparatus of the present invention has the above-described configuration and operation, it can detect the skew angle and the slide amount of the paper sheet with high accuracy.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a paper sheet detection apparatus 1 (hereinafter simply referred to as a detection apparatus 1) according to an embodiment of the present invention. This detection device 1 detects a skew angle θ [deg] and a slide amount S [m] of a sheet M conveyed at a constant speed V [m / s] in the direction of arrow T in the figure.

As indicated by a broken line in FIG. 2, the sheet M is ideally conveyed in a skew-free posture (M ₀ ) at a position separated from the conveyance reference plane B by a certain distance S ₀ [m]. However, depending on the method of taking out the paper sheet M and the transport state, the transport posture may be disturbed, for example, to the posture indicated by a solid line in the figure. The detection apparatus 1 according to the present embodiment detects a distance S [m] (slide amount) from the conveyance reference plane B of the conveyed paper sheet M and an inclination θ [deg] (skew angle) with respect to the conveyance center. Function.

  As shown in FIG. 1, the detection device 1 includes a light emitting unit 2 that is spaced apart from one side (upper side in the drawing) of the paper sheet M to be transported and a light emitting unit across the transport path of the paper sheet M. 2, the first sensor 4 having the light receiving portion 3 that is disposed opposite to the other side of the paper sheet M (downward in the drawing) and the downstream side in the transport direction of the paper sheet M from the first sensor 4. It has the 2nd sensor 7 arrange | positioned spaced apart. The second sensor 7 includes a light emitting unit 5 separated on one side of the paper sheet M and a light receiving unit 6 opposed to the light emitting unit 5 across the conveyance path and separated on the other side of the paper sheet M. The light emitting units 2 and 5 and the light receiving units 3 and 6 of the sensors 4 and 7 have a plurality of light emitting elements and light receiving elements (not shown here) arranged in the width direction, respectively. It is extended in the width direction W that is substantially orthogonal, and is designed to have a length that covers a region that exceeds the entire width that is substantially orthogonal to the conveyance direction of the paper sheet M to be conveyed. Accordingly, each of the sensors 4 and 7 receives the light beam emitted from the light emitting element by the corresponding light receiving element, and detects the passage of the paper sheet M when the paper sheet M blocks the light beam.

  A calculation unit 10 that functions as a posture detection unit of the present invention is connected to the output ends of the first and second sensors 4 and 7. The arithmetic unit 10 samples the outputs of the first and second sensors 4 and 7 at a constant period (here, ΔT [s]) using the clock signal provided by the timer 12, and calculates the arithmetic method described later Accordingly, the conveying posture of the paper sheet M, that is, the skew angle θ and the slide amount S are calculated. The calculation result in the calculation unit 10 is notified to a host device, which is not described here, and is used for processing the paper sheet M.

  In the present embodiment, the first detection point 8 where the paper sheet M blocks the optical path between the light emitting unit 2 and the light receiving unit 3 and the optical path between the light emitting unit 5 and the light receiving unit 6 are paper sheets. The distance δV [m] along the conveyance direction T between the second detection point 9 blocked by M is the distance ΔV [m] in which the paper sheet M is conveyed every sampling period ΔT [s] of the signal described above. ] Is set to a non-integer multiple.

  The paper sheet detection method according to the first embodiment of the present invention will be described below with reference to FIGS. 3 to 6 together with FIGS. In the present embodiment, as shown in FIG. 3, the first sensor 4 has two detection points 8a and 8b (first detection points) for detecting the passage of the paper sheet M, and the second sensor 7 has 2 Assume that there are two detection points 9a and 9b (second detection points). Each detection point 8a, 8b, 9a, 9b is a position where the light beam traveling from the light emitting element to the light receiving element crosses the transport path of the paper sheet M. In FIG. 3, the detection points 8a, 8b, 9a, 9b are Although drawn in a circle, here we will talk about each detection point as if it were a point.

  The two first detection points 8a and 8b are set at positions separated from each other by the distance L [m] in the width direction W described above, and the corresponding two second detection points 9a and 9b are also separated by the same distance in the width direction W. is doing. That is, one second detection point 9a is located at a position separated by δV [m] on the downstream side in the transport direction T with respect to the one first detection point 8a, and the transport direction T with respect to the other first detection point 8b. The other second detection point 9b is located at a position separated by δV [m] on the downstream side.

  As described above, the distance δV [m] between the first detection point 8a (8b) and the second detection point 9a (9b) is conveyed by the paper sheet M within one sampling period ΔT [s]. The distance is set to a non-integer multiple of the distance ΔV [m] (= V × ΔT) to be (conveying speed V [m / s]).

As described above, the detection apparatus 1 uses the first and second sensors 4 and 7 each having two detection points, for example, skew of the skewed paper sheets indicated by M ₁ and M ₂ in FIG. The angle θ is detected. For example, as shown in FIG. 4, when detecting a paper sheet M that is transported from a position indicated by a broken line in a posture with no skew to a position indicated by a solid line, the calculation unit 10 of the detection apparatus 1 is upstream At that time, the paper sheet M is detected via the two detection points 8a and 8b of the first sensor 4 arranged in the first position. Alternatively, depending on the signal sampling timing, the paper sheet M is detected simultaneously at the two detection points 9 a and 9 b of the second sensor 7. That is, in this case, the skew angle θ of the paper sheet M output from the calculation unit 10 is zero [deg].

On the other hand, for example, as shown in FIG. 5, the paper sheet M is conveyed in a posture in which one end (upper end in the figure) of the paper sheet M is inclined to the upstream side in the conveying direction with respect to the other end (lower end in the figure). In this case, the two detection points 8a and 8b of the first sensor 4 or the two detection points 9a and 9b of the second sensor 7 do not detect the paper sheet M at the same time. That is, when the paper sheet M is not detected at the two detection points at the same time, the paper sheet M is skewed. For example, in the example of FIG. 5, the skew angle θ [deg] of the paper sheet M is
θ ≒ arcsin (δV / L)
It becomes.

  As described above, when the skewed paper sheet M is conveyed, the arithmetic unit 10 passes through all the detection points 8a, 8b, 9a, and 9b at the above-described constant sampling period ΔT [s]. The sensor outputs of the first and second sensors 4 and 7 are sampled. In this case, the detection resolution of the skew angle θ [deg] of the paper sheet M depends on the detection pitch of the paper sheet M along the transport direction T, and the detection resolution increases as the detection pitch becomes narrower. θ can be detected with high accuracy.

  This detection pitch is determined by the conveyance speed V [m / s] of the paper sheet M, the detection point interval δV [m] along the conveyance direction T, and the signal sampling period ΔT [s]. For this reason, in order to increase the detection resolution by narrowing the detection pitch, a method of slowing the transport speed, narrowing the interval along the transport direction of the detection point, or shortening the sampling period of the signal can be considered.

  However, since the transport speed of the paper sheet M is determined depending on the process speed, the process speed is decreased by decreasing the transport speed, and the throughput is reduced. Further, there is a limit to shortening the distance along the conveyance direction of the detection point for convenience of the apparatus configuration. Furthermore, when the sampling cycle is shortened, the processing capability of the arithmetic unit 10 may not be able to catch up.

  Therefore, in the present embodiment, the distance between the first detection points 8a and 8b and the second detection points 9a and 9b along the conveyance direction is set to the non-conveyance distance of the paper sheet M for each sampling period. By making it an integer multiple, the number of signal samplings is increased without changing the sampling period ΔT.

  That is, as shown in FIG. 6, the distance δV between the first detection points 8a, 8b and the second detection points 9a, 9b is an integral multiple of the transport distance ΔV of the paper sheet M for each sampling period (here, an example) ΔV = ΔV × 1), for example, the first detection points 8a and 8b at the time of the first signal sampling (the detection points are indicated by ○ in the figure) are the second time of the signal sampling ( The detection point is overlapped with the second detection points 9a and 9b at (indicated by Δ in the figure), and the signal detection resolution cannot be increased.

  On the other hand, the distance δV between the first and second detection points is a non-integer multiple of the transport distance ΔV (here, δV = ΔV × 0.5 and δV = ΔV × 1.5). Detection points (◯, Δ, □ in the figure) on the paper sheet M do not overlap at the time of each sampling, and the signal detection resolution along the transport direction is increased accordingly. it can. Specifically, for example, at the time of the third sampling, in the example in which the detection point interval is set to δV = ΔV × 0.5, a double detection signal can be obtained despite the same sampling period.

In particular, preferably, the distance δV between the detection points 8, 9 of the first and second sensors 4, 7 along the transport direction is:
δV = ΔV (n + 0.5) (where n is a positive integer including 0)
Is desirable. Even if it is a non-integer multiple, it is impossible to take a value very close to an integer multiple, and it is not necessary, and it is desirable to set a detection point at a substantially intermediate point between the transport distances ΔV.

  As described above, according to the paper sheet detection method of the present embodiment, the distance between detection points along the transport direction of the paper sheet M is a non-integer number of the distance at which the paper sheet M is transported for each sampling period. By doubling, the amount of information of signals detected at the same sampling period can be increased, the detection resolution of the paper sheet M along the transport direction can be increased, and the skew angle can be detected with high accuracy.

Next, a modification of the above-described first embodiment will be described with reference to FIGS.
In this modified example, as shown in FIG. 7, the two detection points 9a and 9b of the second sensor 7 are separated from each of the two detection points 8a and 8b of the first sensor 4 by the distance ΔL [ m]. In this way, by shifting the first detection point and the second detection point in the width direction, it is possible to improve the detection accuracy for the paper sheet M that has been folded or missing.

  For example, as shown in FIG. 8, when a paper sheet M having a defect S is conveyed in a state where no skew is generated, even if the defect S is detected at the detection point 8a of the first sensor 4, the second sensor The same defect S is not detected at the detection point 9a. That is, when the first detection point 8a and the second detection point 9a are aligned straight along the transport direction T as in the first embodiment described above, the same defect S is detected at the two detection points 8a and 9a. As a result, the edge of the sheet M cannot be detected at the position of the defect S along the width direction W.

  On the other hand, as shown in the figure, the same defect S is detected by the two sensors 4 and 7 by shifting the first detection point 8a (8b) and the second detection point 9a (9b) in the width direction W. The possibility that the edge of the paper sheet M can be detected by any one of the sensors 4 and 7 can be increased accordingly. Such an effect is the same even when the paper sheet M is conveyed in an inclined state as shown in FIG. 9, and the paper sheet having a defect or a fold is obtained as in the present comparative example. M posture detection accuracy can be increased.

  Next, a paper sheet detection method according to a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, as shown in FIG. 10, the first sensor 4 is a first line sensor 4 ′ in which a large number of first detection points are arranged close to each other along the width direction W, and the second sensor 7 is a second line sensor 7 ′ in which a large number of second detection points are arranged close to each other along the width direction W.

  Here, for easy understanding, as shown in FIG. 10, each detection point of the first line sensor 4 ′ on the upstream side in the conveyance direction (direction of arrow T) of the paper sheet M is indicated by ○, Each detection point of the second line sensor 7 ′ on the downstream side in the transport direction is indicated by Δ. In FIG. 12, the detection points at which the paper sheet M is detected at each sampling timing are indicated by hatching. Further, the time interval for detecting the paper sheet M, that is, the sampling period of the light / dark signal is ΔT [s], the conveyance speed of the paper sheet M is V [m / s], and the paper sheet M is within each sampling time. Is the distance along the conveyance direction between the detection points of each of the line sensors 4 ′ and 7 ′ is δV [m] (<ΔV). In the present embodiment, the distance δV along the transport direction T between the detection points facing each of the line sensors 4 ′ and 7 ′ is set to 0.5, which is the distance ΔV at which the paper sheet M is transported every sampling period ΔT. The distance was set to double (non-integer multiple).

Thus, as shown as a state T ₁ in FIG. 11, when detecting the presence sheet in any of the detection points of the first line sensor 4 in the upstream side ', the arithmetic unit 10 starts collecting data. Here, since it is premised on that the paper sheet M to be transported is skewed, as shown in the figure, the leading edge portion in the transport direction of the paper sheet M to be transported at an inclination is detected first. become.

Then, as shown as a state T ₃ in FIG. 11, ends the collection of data in the arithmetic unit 10 at the time when the other corners of the sheet M is detected in any of the detection points. In this case, it is desirable to detect the corners at both ends of the leading edge of the paper sheet M in the conveyance direction in order to increase the skew angle detection accuracy, but the number of samplings for detecting the paper sheet M is not limited to this. . In FIG. 12, the light and dark signals sampled in _three sampling periods T ₁ , T ₂ , and T ₃ are shown along the movement of the sensor information.

Further, the calculation unit 10 counts how many times the paper sheet M is detected at each detection point based on the collected data as shown in FIG. At this time, the number of detections of the paper sheet M at the i-th detection point from the bottom in the figure is k _i [times]. For example, in the example shown in FIG. 12, since the sheet M is detected five times by combining two line sensors at the 20th detection point from the bottom in the figure, the number of detections of the sheet M in this case Is K ₂₀ = 5 [times].

Then, the calculation unit 10 calculates the skew angle θ of the paper sheet M based on the detected number k _i [times] of the paper sheet M at each detection point counted.
That is, as shown as a state T ₁ in FIG. 11, the detection point has detected the paper sheet M upon start collecting data, and upon completion of the data collection detection points that detected the paper sheet M of the two Assume a right-angled triangle with an acute angle. This right triangle is shown as a solid line R in FIG.

When the distance along the width direction W between the detection points of the line sensors 4 ′ and 7 ′ is d [m], the length of the side along the width direction W of the right triangle R is d (i−1). [M]. Further, when the length of the sides along the conveying direction T of a right triangle R and L _i, the skew angle θ of the paper sheet M, represented by the following formula (1).

Here, L _i is a value represented by the following expression (2) when k _i is an even number,

When k _i is an odd number, the value is represented by the following expression (3).

For example, in the example shown in FIG. 12, when i = 20, L _i is a value represented by the following expression (4).

Furthermore, when the formula (1) is expanded, the following formula (5) is obtained.

When the above equation (5) is added side by side from i = 2 to n, the following equation (6) is obtained.

When formula (6) is transformed, the following formula (7) is obtained.

That is, the skew angle θ of the paper sheet M, if K _i is even, satisfies the following expression (8), if K _i is odd, that satisfies the following equation (9) Become.

  As described above, according to the present embodiment, as in the first embodiment described above, the number of detected signals can be increased without changing the signal sampling period, and the width of the paper sheet M can be increased. Therefore, the detection resolution can be improved, and the detection accuracy of the skew angle θ can be further increased.

By the way, the slide amount S [m] of the paper sheet M can be detected using such two line sensors 4 ′ and 7 ′. That is, i is a number counted from the conveyance reference plane B of the detection point at which the end portion closest to the conveyance reference plane B of the paper sheet M (in this case, the corner portion because the paper sheet M is inclined) is defined as i. When the distance from the conveyance reference plane B to the nearest detection point is S ₀ , the slide amount S of the paper sheet M is
S = i · d + S ₀
It becomes.

  As described above, the detection device 1 according to the present embodiment can detect not only the skew angle θ of the paper sheet M but also the slide amount S with high accuracy.

Next, a modification of the above-described second embodiment will be described with reference to FIGS.
In this modification, as shown in FIG. 13, the number of detection points arranged in the width direction of the first and second line sensors 4 ′ and 7 ′ described above is reduced, and each detection point is correspondingly moved in the transport direction. So that they do not line up with each other. As a matter of course, the distance along the conveyance direction of the two sets of detection points is set to a distance that is a non-integer multiple of the distance that the paper sheet M is conveyed for each sampling of the sensor output.

  For this reason, also in this modified example, as shown in FIGS. 14 and 15, when the conveyed paper sheet M is detected, the detection resolution of the signal in the width direction is reduced as in the second embodiment described above. While being able to raise, the detection accuracy with respect to the paper sheet M which has a crease | fold or a defect | deletion can also be ensured.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above. Furthermore, you may combine the component covering different embodiment suitably.

  For example, in the above-described embodiment, the case where the passage of the paper sheet M is detected at the first detection point and the second detection point that are separated along the conveyance direction has been described. Detection points may be provided at three or more locations. In this case, each detection point needs to have two or more detection points that are separated in the width direction, and the distance along the transport direction is determined by the sheet M at every detection point for each signal sampling. Needless to say, it is a non-integer multiple of the transported distance.

  In the above-described embodiment, it is assumed that the sensor output is detected at a constant sampling period, but conversely, the distance between the detection points along the transport direction is transported by the sheet M at each sampling period. It is also possible to make the signal sampling period indefinite so that it does not coincide with the measured distance.

The block diagram which shows typically the structure of the paper sheet detection apparatus which concerns on embodiment of this invention. The figure for demonstrating the skew angle and slide amount of paper sheets. The figure for demonstrating the structure of the principal part of the detection apparatus which concerns on 1st Embodiment of this invention, and its operation | movement. The figure for demonstrating operation | movement in the case of detecting the paper sheets which have not produced the skew with the apparatus of FIG. The figure for demonstrating operation | movement in the case of detecting the paper sheet which has produced the skew with the apparatus of FIG. The figure for demonstrating the difference when the distance between the detection points along a conveyance direction is made into the integral multiple of the distance by which a paper sheet is conveyed for every sampling, and a non-integer multiple. The figure which shows the modification of 1st Embodiment demonstrated in FIG. The figure for demonstrating the case where the paper sheet which has not produced skew with the apparatus of FIG. 7 is detected. The figure for demonstrating the case where the paper sheet which has produced the skew with the apparatus of FIG. 7 is detected. The figure for demonstrating the structure of the principal part of the detection apparatus which concerns on 2nd Embodiment of this invention, and its operation | movement. The figure which shows the motion of the paper sheet which changes with time with respect to the line sensor at the time of detecting the paper sheet which has produced the skew with the apparatus of FIG. The figure which shows the motion of the sensor information at the time of detecting the paper sheet which has produced the skew with the apparatus of FIG. The figure which shows the modification of 2nd Embodiment demonstrated in FIG. The figure which shows the motion of the paper sheet which changes with time with respect to the line sensor at the time of detecting the paper sheet which has produced the skew with the apparatus of FIG. The figure which shows the motion of the sensor information at the time of detecting the paper sheet which has produced the skew with the apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Paper sheet detection apparatus, 2, 5 ... Light-emitting part, 3, 6 ... Light-receiving part, 4 ... 1st sensor, 7 ... 2nd sensor, 8 ... 1st detection point, 9 ... 2nd detection point, 10 ... Arithmetic unit, 12... Timer.

Claims (12)

A first sensor for detecting the presence or absence of paper sheets at a plurality of first detection points spaced apart from each other in a width direction substantially orthogonal to the paper sheet conveyance direction;
A second sensor for detecting the presence or absence of paper sheets at a plurality of second detection points spaced in the transport direction with respect to each of the plurality of first detection points;
An attitude detection unit that samples sensor outputs at all detection points of the first and second sensors at a constant period and detects the conveyance attitude of the conveyed sheet based on the sensor outputs for a plurality of periods. And having
The distance along the conveyance direction between the first and second detection points is set to a distance that is a non-integer multiple of the distance at which the paper sheet is conveyed for each sampling period. Leaf detection device. When the distance along the conveyance direction between the first and second detection points is δV, and the distance that the paper sheet is conveyed at each sampling period is ΔV,
δV = ΔV (n + 0.5) (where n is a positive integer including 0)
The paper sheet detection apparatus according to claim 1, wherein:   The paper sheet detection apparatus according to claim 1, wherein the first and second detection points are set at positions shifted from each other in the width direction.   The first and second sensors have a plurality of first and second detection points that are close to each other in the width direction over a range exceeding the total length along the width direction of the conveyed paper sheet. 2. The paper sheet detection apparatus according to claim 1, wherein the first and second line sensors are arranged side by side.   5. The paper sheet detection apparatus according to claim 4, wherein the first and second line sensors are set at positions where a large number of the first and second detection points are shifted in the width direction. 6. A first sensor for detecting the presence or absence of paper sheets at a plurality of first detection points spaced apart from each other in a width direction substantially orthogonal to the paper sheet conveyance direction;
A second sensor for detecting the presence or absence of paper sheets at a plurality of second detection points spaced in the transport direction with respect to each of the plurality of first detection points;
A calculation unit that samples sensor outputs at all detection points of the first and second sensors at a constant period, and calculates a skew angle of a conveyed paper sheet based on the sensor outputs for a plurality of periods; Have
The distance along the conveyance direction between the first and second detection points is set to a distance that is a non-integer multiple of the distance at which the paper sheet is conveyed for each sampling period. Leaf detection device. When the distance along the conveyance direction between the first and second detection points is δV, and the distance that the paper sheet is conveyed at each sampling period is ΔV,
δV = ΔV (n + 0.5) (where n is a positive integer including 0)
The paper sheet detection apparatus according to claim 6, wherein:   The paper sheet detection apparatus according to claim 6, wherein the first and second detection points are set at positions shifted from each other in the width direction.   The first and second sensors have a plurality of first and second detection points that are close to each other in the width direction over a range exceeding the total length along the width direction of the conveyed paper sheet. The paper sheet detection apparatus according to claim 6, wherein the first and second line sensors are juxtaposed.   10. The paper sheet detection apparatus according to claim 9, wherein the first and second line sensors are set at positions where a large number of the first and second detection points are shifted in the width direction. The conveyance distance of the paper sheets for each sampling cycle is ΔV [m], and the distance along the conveyance direction between the first detection points and the second detection points respectively corresponding to the first detection points is δV [m]. The distance along the width direction of the first and second detection points is d [m], the number of the detection points through which the paper sheet passes is n [pieces], and from the detection points When the number of times the paper sheet is detected at the i-th detection point counted from the transport reference plane extending in the transport direction at a position deviated is k _i [times], the skew angle θ of the paper sheet [Deg] is
If k _i is an even number,

And
When k _i is an odd number,

The paper sheet detection apparatus according to claim 9, wherein:   The said calculating part samples the said sensor output until the site | part longest in the said width direction of the paper sheet conveyed passes the said 1st and 2nd sensor at least. Paper sheet detection device.

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