JPH0361243A - Sheet thickness detecting apparatus - Google Patents

Abstract

PURPOSE:To prevent the erroneous detection of thickness caused by contamination or the like, by detection of a transparent tape and by providing a determining means for determine a thickness of a sheet in accordance with a difference between a displacement signal issued form a displacement detecting means and a displacement signal stored in a displacement memory means. CONSTITUTION:When a movable roller 12 does not hold a sheet or the like, a displacement signal which is issued from a displacement detecting means 13 during the roller 12 is rotated by a necessary number of revolutions between the initiation of feed of a sheet to the completion of the feed, is stored in a displacement memory means 24. When the roller 12 holds a sheet, a difference between a displacement signal delivered from the displacement detecting means 13 and the displacement signal stored in the displacement memory means 24 is obtained. A determining means 26 determines the thickness of the sheet in accordance with this difference.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paper sheet thickness detection device for detecting the thickness of paper sheets.

(Prior Art) It is necessary to accurately count the number of paper sheets (banknotes) handled in automatic teller machines, automatic teller machines, etc. used in financial institutions. That is, in automatic teller machines and the like, it is necessary to accurately count the number of bills to be withdrawn or deposited. Furthermore, in order to confirm that the deposited banknotes have not been repaired or falsified using tape or the like, it is necessary to detect the presence or absence of tape.

Paper sheet thickness detection devices are used to accurately count the number of banknotes or to detect the presence or absence of tape.

There are mainly two types of paper sheet thickness detection devices.

One is an optical paper sheet thickness detection device that detects the thickness of a banknote by irradiating the banknote with light and detecting the intensity of the transmitted light. The other type is a mechanical sheet thickness detection device that mechanically detects the thickness of banknotes.

In the optical paper sheet thickness detection device, a photoelectric sensor (an element that outputs a voltage depending on the strength of light) is arranged on a conveyance path of paper sheets (banknotes). This photoelectric sensor detects the amount of light that passes through the banknote. In this case, the thickness of the banknote, serious illness, etc. are determined based on the output voltage of the photoelectric sensor, which changes depending on the amount of light that passes through the banknote.

In addition, the mechanical paper sheet thickness detection device is equipped with a pair of rollers (a fixed roller and a movable roller) that transport paper sheets (banknotes), and the amount of displacement of the movable roller that moves according to the thickness of the banknote. The thickness and severity of the disease are detected depending on the condition.

Here, a detailed explanation of the conventional optical paper sheet thickness detection device will be given using FIG.

FIG. 2 is an explanatory diagram of the operation of a conventional optical sheet thickness detection device.

The figure shows voltage on the vertical axis and time on the horizontal axis.

Further, two types of threshold values (threshold value V+ and threshold value ■2) are set for the voltage. Threshold■! is used to determine the presence or absence of banknotes, and the threshold value V2 is used to determine whether there is one banknote or two or more banknotes. In other words, the voltage output from the photoelectric sensor is
If the threshold value ■ is less than or equal to 1 and higher than the threshold value v2, it is determined that one bill has been conveyed. Further, if the voltage output from the photoelectric sensor is equal to or less than the threshold value ■2, it is determined that two or more banknotes have been conveyed. Incidentally, if the voltage output from the photoelectric sensor is higher than the threshold value ■1, it is determined that the banknote is not being conveyed. Waveform A in the figure is a waveform when one banknote is transported, and waveform B is a waveform when two banknotes are transported (seriously affected).

As described above, the thickness of the banknote can be determined based on the output voltage of the photoelectric sensor.

Next, a detailed explanation of the conventional mechanical sheet thickness detection device will be given using FIG.

FIG. 3 is an explanatory diagram of the operation of a conventional mechanical sheet thickness detection device.

The figure shows voltage on the vertical axis and time on the horizontal axis.

Further, a threshold value (3) is set for the voltage. The threshold value V3 is used to determine whether the number of transported banknotes is one or two or more. In the figure, waveform C is a waveform when one banknote is transported, and waveform C is a waveform when two banknotes are transported (seriously affected). Note that even if only one banknote is transported, if a tape or the like is attached to the banknote, a waveform E as shown by a broken line in the waveform C is generated.

As described above, the thickness of the banknote can be determined based on the displacement of the movable roller.

(Problem to be Solved by the Invention) By the way, the paper sheet thickness detection device not only determines whether the paper sheet is seriously ill from the thickness of the sheet, but also can identify banknotes that have been repaired or altered with tape or the like. There is a need to.

However, the optical sheet thickness detection device cannot detect a transparent tape attached to a banknote. That is, this is because the light from the photoelectric sensor passes through the tape. Furthermore, the amount of light that passes through soiled banknotes is significantly reduced, and there is a possibility that even a single banknote may be identified as seriously ill.

Further, in the case of a mechanical paper sheet thickness detection device, the processing accuracy of the movable roller, that is, the processing accuracy of the surface of the roller and the rotating shaft that supports the roller, etc., becomes a problem.

FIG. 4 shows a layout diagram of the main parts of a conventional mechanical sheet thickness detection device.

In the figure, a fixed roller 1 and a movable roller 2 are arranged facing each other. The fixed roller 1 and the movable roller 2 are provided with rotating shafts 1a and 2a, respectively.

Here, the radius of the fixed roller 1 is R1, the eccentricity is E, the radius of the movable roller 2 is r, and the eccentricity is e. Also, banknotes 3
Let the thickness of t be t.

Furthermore, when there is no banknote 3 being conveyed by the fixed roller 1 and the movable roller 2, that is, when the fixed roller 1 and the movable roller 2 are in contact, the distance between the rotating shaft 1a and the rotating shaft 2a is y. shall be. Moreover, when the banknote 3 is present between the fixed roller 1 and the movable roller 2, that is, when the banknote 3 is being conveyed, the distance between the rotation shaft 1a and the rotation shaft 2a is defined as yI. Therefore, the following formula holds.

(R-E) + (r-e)≦y0≦(RYE) +(
rye) ... (1) (R-E) + (r-e)
+t≦yl≦(RYE) + (rye) +t ・
...(2) Here, if the displacement amount of the movable roller 2 is δ, then δ=y+-yo...(3) From equations (1), (2), and (3), -2(Eve) +t ≦δ≦2 (Eve) +t
...(4). As is clear from equation (4), the displacement amount δ has an error of ±2 (Eve) with respect to the thickness t of the banknote 3. Considering this error, the detection limit for detecting that the banknote 3 is one banknote is set as δ. Then, the relationship between this detection limit and processing accuracy is determined by the following equation.

δ. = 4 (Eve) (5) If the machining accuracy of the fixed roller 1 and the movable roller 2 are revised to be the same, the following equation holds true.

E=δ (6) Therefore, from equation (6), equation (5) can be expressed as follows.

δ. =8E (7) Here, since the thickness of the tape to be detected is about 50 μm, the detection limit is set to about half of that thickness, and the maximum value of eccentricity is obtained from equation (7).

E = e = 25gm / 8 = 3 μm...
- (8) In this way, the maximum value of eccentricity is 3 μm, and extremely high precision processing is required. Therefore, it has been extremely difficult to reduce the cost of the paper sheet thickness detection device.

The present invention has been made with attention to the above points, and it is possible to detect transparent tape and prevent misjudgment due to dirt, etc., and furthermore, it is possible to easily reduce costs without performing high-precision processing. The object of the present invention is to provide a paper sheet thickness detection device.

(Means for Solving the Problems) The paper sheet thickness detection device of the present invention includes a fixed roller for transporting paper sheets, a fixed roller that clamps the paper sheets, and a paper sheet thickness detecting device for transporting the paper sheets. A movable roller that is displaced in accordance with the thickness of the paper sheet, a displacement amount detection means that detects the amount of displacement of the movable roller and outputs a displacement signal, and a movable roller that is displaced in accordance with the thickness of the paper sheet. a displacement amount storage means for storing a displacement signal outputted by the displacement amount detection means while the movable roller rotates necessary from the start of conveyance to the end of conveyance of the paper sheet when no leaves are being held; When the movable roller clamps the paper sheet, the thickness of the paper sheet is determined based on the difference between a displacement signal output by the displacement amount detection means and a displacement signal stored in the displacement amount storage means. It is equipped with means.

Further, there is a fixed roller that conveys the paper sheet, and a roller that pinches the paper sheet together with the fixed roller and transports the paper sheet, and a roller that is displaced in accordance with the thickness of the paper sheet. a movable roller that detects the amount of displacement of the movable roller and outputs a displacement signal; and a displacement amount detection means that detects the amount of displacement of the movable roller and outputs a displacement signal; a displacement storage means for storing displacement signals outputted by the displacement detection means for at least two of the paper sheets during rotation required from the start to the end of conveyance; and at least two displacement signals stored in the displacement storage means. an average calculation means for averaging the displacement signals for one sheet to obtain a displacement signal for one sheet; and a displacement signal output from the displacement amount detection means and the average calculation when the movable roller pinches the paper sheet. and determining means for determining the thickness of the sheet based on the difference between the displacement signal and the displacement signal averaged by the means.

(Function) When the movable roller is not holding paper sheets, the displacement signal output by the displacement detection means during the rotation required from the start of paper sheet conveyance to the end of conveyance is detected by the displacement amount. Store it in a storage means. Next, when the movable roller pinches the paper sheet, the difference between the displacement signal output by the displacement amount detection means and the displacement signal stored in the displacement amount storage means is determined. The determining means determines the thickness of the paper sheet based on this difference.

In addition, when the movable roller is not holding paper sheets, the displacement signal output by the displacement amount detection means during the rotation required from the start of conveyance of the paper sheet to the end of conveyance is transmitted to at least the paper sheet 2.
It is stored in the sheet displacement amount storage means. The displacement signals for at least two sheets of paper are averaged by an averaging means. Next, when the movable roller pinches the paper sheet, the difference between the displacement signal output by the displacement amount detection means and the displacement signal averaged by the average calculation means is determined. The determining means determines the thickness of the paper sheet based on this difference.

(Embodiment) FIG. 1 shows a block diagram of a sheet thickness detection device according to a first embodiment of the present invention.

In the figure, the paper sheet thickness detection device 10 includes a fixed roller 1
1, a movable roller 12, a displacement detection means 13, an angle detection means 14, a sheet detection means 15, and a signal processing section 16.

The fixed roller 11 and the movable roller 12 are connected by a power transmission mechanism such as a gear, and rotate in synchronization with each other by driving a motor (not shown). The displacement amount detection means 13 detects the displacement amount of the movable roller 12. Specifically, it outputs an output voltage corresponding to the displacement of the movable roller 12. This change in output voltage is caused by a resistance value that changes with the displacement of the movable roller 12. The angle detection means 14 is composed of a rotary encoder 17 and an index sensor 18. The rotary encoder 17 detects the rotation angle of the movable roller 12, and is composed of a slit plate, a photoelectric sensor, and the like. The index sensor 18 detects one revolution of the movable roller 12, and like the rotary encoder 17, it is composed of a slit plate, a photoelectric sensor, and the like. The paper sheet detection means 15 is composed of a photoelectric sensor or the like that detects the presence or absence of paper sheets sandwiched between the fixed roller 11 and the movable roller 12.

The signal processing section 16 is composed of an analog-to-digital converter (A/D converter) 21, a counter circuit 22, a delay circuit 23, a displacement storage means 24, a subtraction means 25, and a determination means 26.

The output of the displacement detection means 13 is connected to the input of the A/D converter 21. The output of the rotary encoder 17 is connected to the inputs of an A/D converter 21, a counter circuit 22, and a delay circuit 23. Index sensor 1
The output of 8 is connected to the input of the counter circuit 22. The output of the paper sheet detection means 15 is connected to the input of the delay circuit 23. The outputs of the A/D converter 21, the counter circuit 22, and the delay circuit 23 are connected to a displacement storage means 24. The outputs of the displacement storage means 24 and the A/D converter 21 are connected to the input of the subtraction means 25. The output of the subtracting means 25 is connected to the input of the determining means 26.

The A/D converter 21 converts an analog voltage value inputted from the displacement detection means 13 into a digital voltage value. The counter circuit 22 includes a register and the like that counts the output pulses of the rotary encoder 17 and outputs an address signal based on the counting result. Note that this counter circuit 22 is reset by the output of the index sensor 18. The delay circuit 23 is composed of a flip-flop or the like that delays the output signal of the paper sheet detection means 15 by a predetermined time and outputs the delayed signal. The displacement storage means 24 is composed of a RAM or the like that stores the output of the A/D converter 21. The subtraction means 25 includes the A/D converter 21 and the displacement storage means 24.
It calculates the difference between the outputs of . The determining means 26 determines, based on the calculation result of the subtracting means 25, whether the paper sheet being conveyed while being held between the fixed roller 11 and the movable roller 12 is seriously affected or whether tape or the like is pasted on it. It is something to do.

FIG. 5 shows a perspective view of the main parts of the paper sheet thickness detection device of the present invention.

In the figure, a movable roller 1 is placed above the fixed roller 11.
2 are arranged facing each other. The fixed roller 11 and the movable roller 12 are supported by rotating shafts 11a and 12a, respectively. The rotating shafts 11a and 12a are connected by drive gears (not shown), respectively, and receive driving force from a motor (not shown) to perform synchronous rotation (in the directions of arrows A and B).

Now, paper sheet detection means 15 is arranged on the conveyance path in front of the fixed roller 11 and the movable roller 12. This paper sheet detection means 15 includes an issuing element 15a and a light receiving element 1.
It is composed of a photoelectric sensor consisting of 5b. On the other hand, a rotary encoder 17 is connected to the left side of the rotating shaft 12a of the movable roller 12. Further, on the right side of the rotating shaft 12a of the movable roller 12, a displacement amount detection means 13 and an index sensor 18 are provided.

The rotary encoder 17 outputs pulses according to the rotation angle of the movable roller 12.

The displacement detection means 13 is provided with a link mechanism 13a that is supported by a rotation shaft 12a and moves up and down (in the direction of arrow C) along with the displacement of the movable roller 12.

A variable resistor VR is connected to the point of action 13b of the link mechanism 13a.
is connected. The index sensor 18 includes a slit plate 18b provided with a slit 18a, and a photoelectric sensor 18c. The photoelectric sensor 18c includes an emitting section 18d and a light receiving section 18e. This index sensor 18 outputs a pulse every time the movable roller 2 makes one rotation.

Returning now to FIG. 1, the explanation will continue.

The A/D converter 21 samples the displacement amount input from the displacement amount detection means 13 at the timing of the pulse output from the rotary encoder 17, and converts it into a digital signal. Further, the counter circuit 22 is reset by the pulse output from the index sensor 18, and then counts the pulses output from the rotary encoder 17 (1
- 15). The rotary encoder 17 outputs the counting result to the displacement storage means 24 as an address signal. Note that the displacement storage means 24 stores the signal from the A/D converter 21 when the output signal of the delay circuit 23 is at a low level. Further, when the output signal of the delay circuit 23 is at a low level, its contents are outputted to the subtraction means 25.

The operation of the paper sheet thickness detection device having the above configuration will be explained with reference to FIG.

FIG. 6 is a waveform diagram according to the first embodiment of the present invention.

FIG. 6(A) shows the output signal of the paper sheet detection means 15. FIG. 2B shows the output signal of the delay circuit 23. FIG. 2C shows the output pulses of the low reencoder 17. FIG. 2D shows the output pulses of the index sensor 18. (E) in the figure shows the address output by the counter circuit 22. Same figure (
F) shows the output signal of the displacement amount detection means 13.

(G) in the same figure shows the output signal of the A/D converter 21. (H) in the same figure shows the output signal of the displacement amount storage means 24. (I) of the same figure shows the output signal of the subtraction means 25.

FIG. 6 shows two cycles, a first cycle and a second cycle.

Now, the first cycle shown in FIG. 6 will be explained.

This first cycle consists of fixed roller 11 and movable roller 1.
This is a cycle in which the movable roller 12 rotates once when the rollers 2 and 2 are in contact with each other. That is, the thickness of the banknote is not detected.

At this time, as the movable roller 12 rotates, the rotary encoder 17 outputs pulses at regular intervals as shown in FIG. 6(C). This pulse is the A/D converter 2
1, the signal is output to the counter circuit 22 and the delay circuit 23. Further, as shown in FIG. 6(D), the index sensor 18 outputs a pulse every time the movable roller 12 rotates once. This pulse is output towards the counter circuit 22.

Now, as can be seen from FIGS. 6(C) and (D), the rotary encoder 17 outputs 16 pulses during one rotation of the movable roller 12. Further, the counter 22 is
In response to the output pulses of the rotary encoder 17, the counted values (addresses O to 15) are outputted to the displacement storage means 24.

In the A/D converter 21, the displacement amount inputted from the displacement amount detection means 13 (FIG. 6 (F))
7 is sampled at the timing of the output pulse and converted into a digital signal (FIG. 6 (G)). The displacement amount storage means 24 stores the displacement amount output from the A/D converter 21 based on the address signal output from the counter circuit 22 (FIG. 6(H)). When the output of the delay circuit 23 is at a high level, the variable displacement amount storage means 24 stores the displacement amount from the A/D converter 21 and at the same time stores the displacement amount from the subtraction means 2.
Output to 5. Further, when the output of the delay circuit 23 becomes low level, the amount of displacement from the A/D converter 21 is stored.

Once the movable roller 12 has completed one rotation, the second cycle begins. Here, when the second cycle starts, the paper sheet detection means 15 detects paper sheets, and as shown in FIG. 6(A),
Assume that a low level signal is output. In this case, the delay circuit 23 delays the pulse output from the rotary encoder 17 by three pulses and outputs a low level signal to the variable position storage means 24. Here, the reason why the delay circuit 23 outputs a signal with a delay of three pulses is that when the time corresponding to three pulses has elapsed, the leading edge of the banknote moves from above the paper sheet detection means 15 to the fixed roller 11 and the movable roller. This is because the object is transported to a position where it is held between the objects 12 and 12. The displacement amount storage means 24 interrupts storage of the displacement amount output from the A/D converter 21 and outputs the already stored displacement amount to the subtraction means 25. As a result, the subtraction means 25 receives two inputs: the displacement amount from the A/D converter 21 and the displacement amount stored in the displacement amount storage means 24. Subtraction means 25
Then, the subtraction result (a) as shown in FIG. 6(I) is outputted to the determining means 26. Note that the subtraction result shown in FIG. 6(I) is stored in the displacement amount storage means 24 as
The amount of displacement related to the eccentricity of the A/D converter 2 is stored.
This is because from 1, the amount of displacement related to the thickness of the banknote is output. The determining means 26 determines, based on the output of the subtracting means 25, whether there is only one bill or not, and whether or not there is no tape or the like attached. In the case of Figure 6 (I),
Since the waveform of the subtraction result has two levels, it is determined that tape or the like is pasted on the banknote. Depending on the result of this determination, countermeasures such as returning the banknotes will be taken.

Next, FIG. 7 shows a block diagram of a sheet thickness detection device according to a second embodiment of the present invention.

The paper sheet thickness detecting device 1o shown in the figure has a toggle flip-flop 31,
The configuration is such that a write control means 32 and an average calculation means 33 are newly provided. Further, the displacement amount storage means 24
First displacement amount storage means 24a, second displacement amount storage means 2
The difference is that it is composed of 4b. Therefore, duplicate explanations will be omitted as appropriate.

Now, the index sensor 18 is connected to the input of the toggle flip-flop 31, and the output side is connected to one input of the write control means 32. A delay circuit 23 is connected to the other input of the write control means 32. The output of the write control means 32 is connected to the first and second displacement storage means 24a, 24b. The outputs of the first and second displacement amount storage means 24a, 24b are connected to the average calculation means 33. The output of the average calculation means 33 is connected to the subtraction means 25.

The toggle flip-flop 31 is composed of a T flip-flop or the like whose output is inverted each time a pulse is generated. The write control means 32 includes first and second displacement amount storage means 24a.

This is a circuit that alternately sets 24b to a write state. This write control means 32 is composed of an inverter 32a and two AND gates 32b and 32c. The input of the inverter 32a is connected to the output of the toggle flip-flop 31. The output of inverter 32a is connected to one input of AND gate 32b. The output of the AND gate 32b is connected to the first displacement storage means 24a. One input of AND gate 32C is connected to the input of inverter 32a. and gate 3
The output of the delay circuit 23 is connected to the other inputs of 2b and 32c.

The displacement storage means 24 is a storage element composed of a RAM or the like, and its storage area is divided into two. The average calculation means 33 includes first and second displacement amount storage means 24a, 2.
It is composed of a register and the like that calculates the average value of the displacement amounts stored in 4b.

In the paper sheet thickness detection device having the above configuration, the mechanism around the movable roller 12 is the same as that described previously in FIG. 5.

Now, the operation of the paper sheet thickness detecting device having the above configuration will be explained with reference to FIG.

FIG. 8 is a waveform diagram according to the second embodiment of the present invention.

FIG. 8(A) shows the output signal of the paper sheet detection means 15. FIG. 2B shows the output signal of the delay circuit 23. FIG. 2C shows the output pulses of the rotary encoder 17. CD) in the same figure shows the output pulse of the index sensor 18. (E) in the figure shows the output address of the counter circuit 22. Same figure (F)
shows the output waveform of the toggle flip-flop 31. (G) in the figure shows a write control signal output from the write control circuit to the first displacement amount storage means 24a.

(H) in the figure shows a write control signal output from the write control means 32 to the second displacement amount storage means 24b. (I) of the same figure shows the output waveform of the displacement amount detection means 13. (J) in the figure shows the output signal of the A/D converter 21. (K) of the same figure shows the first displacement storage means 2.
4a is shown. (L) in the same figure shows the output signal of the second displacement amount storage means 24b. Same figure (M
) indicates the output signal of the average calculation means 33. (N) in the figure shows the output signal of the subtraction means 25.

Figure 8 shows three cycles from the first cycle to the third cycle.
Two cycles are shown.

First, the first and second cycles will be explained.

In these first and second cycles, when the fixed roller 11 and the movable roller 12 are in contact with each other, the movable roller 12
This is a cycle in which the wheel rotates twice.

That is, the thickness of the banknote is not detected.

The A/D converter 21 samples the displacement amount input from the displacement amount detection means 13 at the timing of the pulse output from the low-resolution encoder 17, and converts it into a digital signal. Further, the counter circuit 22 is reset by the pulses output from the index sensor 18, and thereafter counts the pulses output from the rotary encoder 17 (outputs from addresses 1 to 14). The rotary encoder 17 outputs the counting result to the displacement storage means 24 as an address signal. The displacement amount storage means 24 stores the displacement amount output from the A/D converter 21 based on the address signal output from the counter circuit 22.

On the other hand, when the toggle flip-flop 31 receives a pulse to start the first cycle from the index sensor 18, its output becomes high level, as shown in FIG. 8(F). As a result, the write control means 32 operates as shown in FIG.
As shown in G) and (H), the first displacement amount storage means 24a
A high level write control signal is output to the second displacement amount storage means 24b, and a low level write control signal is output to the second displacement amount storage means 24b. Therefore, the first displacement amount storage means 24a is set to a write enabled state, and the second displacement amount storage means 24b is set to a write prohibited state.

Therefore, the amount of displacement output by the A/D converter 21 is
At the same time as being stored in the first displacement amount storage means 24a, it is outputted to the average calculation means 33. Further, the previously stored displacement amount is outputted from the second displacement amount storage means 24b to the average calculation means 33.

Next, the second cycle will be explained.

When the toggle flip-flop 31 receives a pulse from the index sensor 18 that starts the second cycle,
As shown in FIG. 8(F), the output is set to low level. As a result, the write control means 32 operates as shown in FIG. 8(G).
As shown in (H), a high level write control signal is output to the second displacement amount storage means 24b and a low level write control signal is output to the first displacement amount storage means 24a. Therefore, the second displacement amount storage means 24b is in the write-enabled state, and the second displacement amount storage means 24b is in a write-enabled state.
a is set to a write-protected state.

Therefore, the amount of displacement output by the A/D converter 21 is
At the same time as being stored in the second displacement amount storage means 24b, it is outputted to the average calculation means 33. Further, the first displacement amount storage means 24a outputs the displacement amount previously stored in the first cycle to the average calculation means 33.

Now, it is assumed that in the second cycle, a noise component T as shown in FIG. 8(I) is generated due to vibrations, fluctuations in power supply voltage, or the like. In this case, the noise component U corresponding to this noise component is stored in the second displacement amount storage means 24b.
(FIG. 8(J)) is stored and simultaneously output to the average calculation means 33. This noise component U is halved by the calculation of the average calculation means 33. That is, this is to take an average with the displacement amount previously stored in the first displacement amount storage means 24a. Furthermore, the calculation result of the subtraction means 25 is also output with the noise component reduced to half (noise component V).

In the determination means 26, since the level of this noise component V is low, it does not affect the determination of the thickness of the banknote. That is,
Noise components usually occur at a delicate level that may or may not affect the determination of the thickness of paper sheets. Therefore, by reducing the level to half, it becomes possible to ensure that the determination of the thickness of paper sheets is not affected.

Next, the third cycle will be explained.

At the same time as the third cycle starts, the paper sheet detection means 15
It is assumed that the sensor detects paper sheets and outputs a low level signal as shown in FIG. 8(A). In this case, the delay circuit 23 delays the output from the rotary encoder 17 by three pulses and outputs a low level signal to the displacement amount storage means 24. The toggle flip-flop 31 is the third
Index sensor 1
8, the output becomes high level as shown in FIG. 8(F). As a result, the write control means 32 writes the first and second displacement amount storage means 24a as shown in FIGS. 8(G) and 8(H).

24b both output low-level write control signals. That is, it is set to a write-inhibited state.

Therefore, the first and second displacement amount storage means 24a, 24
b outputs the previously stored displacement amount to the average calculation means 33. The previous noise component U is stored in the second displacement amount storage means 24b, but as in the second cycle,
The level is halved and output to the subtraction means 25. The subtraction means 25 calculates the difference between the output of the average calculation means 33 and the output of the A/D converter 21, and outputs a waveform as shown in FIG. 8(N). This waveform shows a banknote with tape attached to it. Although this waveform is affected by noise components, the level thereof is extremely low, so it does not affect the detection of the thickness of the banknote.

The present invention is not limited to the above embodiments.

In the embodiment, the paper sheets are described as banknotes, but the present invention is not limited to banknotes, and can also be applied to, for example, to prevent serious damage to recording paper of copying machines, printers, etc. Furthermore, the movable roller 12 does not necessarily transport one bill at a time.
It does not have to be configured to rotate, and may be several rotations or one rotation or less. In this case, rotary encoder 1
7 and the pulse period output by the index sensor 18 will also be changed accordingly. Further, instead of the index sensor 18, one rotation of the movable roller 12 may be recognized by counting the output of the rotary encoder 17. Furthermore, the displacement amount storage means 24 includes one or two displacement amount storage means 24.
The configuration is not limited to storing the displacement related to the rotation of the movable roller 12 required to convey a sheet of banknotes.

(Effects of the Invention) According to the paper sheet thickness detection device of the present invention configured as described above, it is possible to accurately determine the thickness of banknotes to which transparent tape is attached or soiled banknotes, that is, whether the banknotes are seriously ill, etc. I can do it. Furthermore, since high-precision machining is not required for the fixed roller and the movable roller, the cost can be easily reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a paper sheet thickness detection device according to a first embodiment of the present invention, FIG. 2 is an operational explanatory diagram of a conventional optical paper sheet thickness detection device, and FIG. 3 is a conventional paper sheet thickness detection device. Fig. 4 is a layout diagram of the main parts of the conventional mechanical paper sheet thickness detection device, and Fig. 5 shows the paper sheet thickness detection device of the present invention. A perspective view of the main parts of the device, FIG. 6 is a waveform diagram according to the first embodiment of the present invention, and FIG. 7 is a block diagram of the sheet thickness detection device according to the second embodiment of the present invention. FIG. 8 is a waveform diagram according to a second embodiment of the present invention. 11...Fixed roller, 12...Movable roller, 13.
...Displacement amount detection means, 15...Paper sheet detection means, 17
... rotary encoder, 18 ... index sensor, 21 ... A/D converter, 22 ... counter circuit, 23 ... delay circuit, 24 ... displacement amount storage means, 2
5... Subtraction means, 26... Judgment means, 31... Toggle flip-flop, 32... Write control means, 33... Average calculation means. Time (↑) Fig. 2 Fig. 3 Layout diagram of the conventional O-type mza detection device Fig. 4

Claims (1)

[Scope of Claims] 1. A fixed roller for transporting paper sheets, which together with the fixed roller clamps the paper sheets and transports the paper sheets, the thickness of the paper sheets being a movable roller that displaces in response to the movement of the paper; a displacement detection means that detects the displacement of the movable roller and outputs a displacement signal; and when the movable roller is not holding the sheet, the movable roller a displacement storage means for storing a displacement signal outputted by the displacement detection means during the rotation required from the start of conveyance to the end of conveyance of the paper sheet; when the movable roller pinches the paper sheet; A paper sheet characterized by comprising: a determination means for determining the thickness of the paper sheet based on a difference between a displacement signal outputted by the displacement amount detection means and a displacement signal stored in the displacement amount storage means. Thickness detection device. 2. A fixed roller that transports paper sheets; a roller that, together with the fixed roller, clamps the paper sheets and transports the paper sheets; a movable roller that detects a displacement amount of the movable roller and outputs a displacement signal; when the movable roller does not nip the paper sheet, the movable roller transports the paper sheet. displacement amount storage means for storing displacement signals output by the displacement amount detection means for at least two of the paper sheets during rotation required from the start to the end of conveyance; and at least two displacement signals stored in the displacement amount storage means. an average calculation means for averaging the displacement signal for one sheet to obtain a displacement signal for one sheet; and a displacement signal output from the displacement amount detection means and the average calculation when the movable roller pinches the paper sheet. 2. The paper sheet thickness detecting device according to claim 1, further comprising determining means for determining the thickness of the paper sheet based on a difference between the displacement signal and the displacement signal averaged by the means.