JPH0361244A - Sheet thickness detecting apparatus - Google Patents

Abstract

PURPOSE:To securely discriminate an overlap feeding of sheets and a sheet on which a tape or the like is applied, even though dust sticks to a roller, by providing a determining means for comparing a result of detection by a roller outer diameter detecting means with a reference value which is set independently, and for determining whether a sheet is normally fed or not, in accordance with a result of the comparison. CONSTITUTION:Before a sheet or the like is clamped, a displacement signal which is issued from a displacement detecting means 13 during a roller 12 being rotated by a necessary number of revolutions between the initiation of feed of a sheet and the completion of the feed, is stored in a displacement memory means 25. Then, after the roller 12 holding and feeding a sheet, a roller outer diameter detecting means 25 detects a difference between a displacement signal issued from the displacement detecting means 13 and the displacement memory means 25. A comparing means 24 compares a result of detection with a reference value which has been previously set in a memory means 27. An operation determining means 29 determines whether the sheet is normally fed or not in accordance with a result of comparison.

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 That is, in automatic teller machines and the like, it is necessary to accurately count the number of bills to be withdrawn or deposited.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 v1 and threshold value V2) are set for the voltage. The threshold value ■1 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 it is less than the threshold value V1 and higher than the threshold value ■2, 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 v2, 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 (1), and there is a risk that even one banknote may be identified as seriously ill.

Furthermore, in the case of a mechanical paper sheet thickness detection device, dust or the like may adhere to the surface of the roller and the movable roller may be displaced. When determining the thickness of a banknote in such a state, it is impossible to determine whether the displacement of the movable roller 12 is due to dust or tape, etc., and even if the banknote is normal, It was determined that it was abnormal.

The present invention has been developed with the above points in mind, and it is not affected by transparent tape or dirt, and even if dust adheres to the roller, it can reliably prevent serious damage to paper sheets and tape, etc. It is an object of the present invention to provide a paper sheet thickness detecting device capable of distinguishing pasted paper sheets.

(Means for Solving the Problems) The paper sheet thickness detection device of the present invention includes a fixed roller, a paper sheet that is held together with the fixed roller, and the paper sheet is conveyed. a movable roller that moves in accordance with the thickness of the paper sheet; a displacement detection means that detects the amount of displacement of the movable roller and outputs a displacement signal; displacement amount storage means for storing a displacement signal outputted by the displacement amount detection means during the rotation required from the start of conveyance to the end of conveyance of the paper sheet;
Roller outer diameter change detection means for detecting a difference between a displacement signal outputted by the displacement amount detection means and a displacement signal stored in the displacement amount storage means after the movable roller pinches and conveys the paper sheet. and an operation determining means for comparing the detection result by the roller outer diameter change detecting means with a separately set reference value and determining whether the conveyance of the paper sheet is operating normally based on the comparison result. It is.

(Function) Before the above-mentioned device clamps the paper sheet, the displacement signal outputted by the displacement detection means during the necessary rotation from the start of conveyance to the end of conveyance of the paper sheet is stored in the displacement storage means. let Next, after the movable rollers pinch and convey the paper sheets, the roller outer diameter change detection means detects the difference between the displacement signal output by the displacement amount detection means and the displacement signal stored in the displacement amount storage means. . This detection result is compared with a preset reference value, and based on this comparison result, the operation determining means determines whether or not conveyance of paper sheets is operating normally.

(Example) FIG. 1 shows a block diagram of a paper sheet thickness detection device 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 1 and the movable roller 12 are connected by a power transmission mechanism such as a gear, and are rotated 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 in accordance with the displacement of the movable roller 12. This change in output voltage is caused by a resistance value that changes in response to 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, etc., which is held between the fixed roller 11 and the movable roller 12 and detects the presence or absence of filter paper sheets.

Now, the signal processing section 16 includes an analog-to-digital converter (A/D converter) 21, a counter circuit 22, a delay circuit 23, a write control circuit 24, and a displacement storage means 25.
, a subtraction circuit (roller outer diameter change detection means) 26, a displacement reference value storage means 27, a comparison means 28, and two determination means.

The output of the displacement detection means 13 is connected to the input of the A/D converter 21. The output of the low-resolution 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 write control circuit 24 are connected to displacement storage means 25 (first displacement storage means 25a, second displacement storage means 25b). The output of the displacement storage means 25 is connected to a subtraction circuit 26. Subtraction circuit 26
The output of the displacement reference value storage means 27 is connected to the comparison means 28. The output of the comparing means 28 is connected to the determining means 29.

The A/D converter 21 converts an analog displacement amount (voltage value) inputted from the displacement amount detection means 13 into a digital displacement amount (voltage value). The counter circuit 22 includes a register and the like that counts the output pulses of the low reencoder 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 5. 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 write control circuit 24 is
It consists of a gate circuit and the like that alternately sets the first and second displacement amount storage means 25a, 25b to a write state. The displacement amount storage means 25 is composed of a RAM or the like that stores the output signal (displacement amount) of the A/D converter 21. The subtraction circuit 26 includes a displacement amount storage means 25 (first and second displacement amount storage means 25a).

25b) is used to calculate the difference between the output signals.

The displacement reference value storage means 27 is composed of a register or the like that stores a predetermined threshold value (for example, °"○") indicating that the displacement of the movable roller 12 is normal.The comparison means 28 is composed of a subtraction means. 26 output and displacement reference value storage means 2
7 and outputs a high level signal if they match, and outputs a low level signal if they do not match. The determining means 29 determines whether the conveyance of the banknotes is normal or not based on the level of the force signal output from the comparing means 28.

FIG. 4 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 revolution.

Here, we will return to FIG. 1 and continue the explanation.

The second A/D converter 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
- 14). The rotary encoder 17 outputs the counting result to the displacement storage means 25 as an address signal. Incidentally, when the output signal of the delay circuit 23 is at a low level, the displacement storage means 25 stores the signal from the A/D converter 21 and simultaneously outputs the signal to the subtraction circuit 26.

Further, when the output signal of the delay circuit 23 is at a low level, the stored contents are outputted to the subtraction circuit 26.

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

FIG. 5 is a waveform chart showing the operation of the sheet thickness detection device of the present invention.

FIG. 5(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. 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 a write control signal output from the write control circuit 24 to the first displacement amount storage means 25. Same figure (
G) shows a write control signal output from the write control circuit 24 to the second displacement amount storage means 25. Same figure (
H) indicates the output signal of the A/D converter 21. (I) of the same figure shows the output signal of the first displacement amount storage means 25a. (J) in the same figure shows the output signal of the second displacement amount storage means 25b. (K) in the figure shows the output signal of the subtraction means 26. (L) in the figure shows the output signal of the comparing means 28.

Figure 5 shows three cycles from the first cycle to the third cycle.
Two cycles are shown.

Now, in the A/D converter 21, the displacement amount detection means 13
The amount of displacement input from the rotary encoder 17 is sampled at the timing of the pulse output from the rotary encoder 17, and converted into a digital signal (FIG. 5(H)). 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 (outputs from addresses 1 to 14) (FIG. 5(E)). outputs the counting result to the displacement storage means 25 as an address signal. The displacement amount storage means 25 stores the displacement amount output from the A/D converter 21 based on the address signal output from the counter circuit 22. A predetermined timing is provided for this storage. That is, write control circuit 2
4 outputs a low-level write control signal as shown in FIGS. 5(F) and 5(G) every time the delay circuit 23 outputs a high-level signal. That is, each time the delay circuit 23 outputs a high level signal, a low level write control signal is alternately input to the first and second displacement amount storage means 25a and 25b. The displacement storage means 25 stores the digital signal output from the A/D converter 21 when this write control signal is at a low level.

Now, the first cycle will be explained.

As shown in FIG. 5(A), it is assumed that the paper sheet detection means 15 detects a banknote and outputs a low-level detection signal (a). Accordingly, as shown in FIG. 5(B), a delay occurs. The circuit 23 outputs a detection signal with a delay of a predetermined time (three pulses output from the rotary encoder 17). As shown in FIG. 5(G), the write control circuit 24
A high level write control signal is output to the displacement amount storage means 25b. As a result, in this first cycle, the displacement storage means 25 outputs the already stored signal to the subtraction circuit 26 without storing the digital signal output from the A/D converter 21. When the conveyance of nine banknotes is completed as shown in FIG. 5(A), the paper sheet detection means 15
Outputs a high level detection signal again. In response to this,
The output of the delay circuit 23 also becomes high level. Then, the write control circuit 24 outputs a low level write control signal to the first displacement amount storage means 25a. The first displacement storage means 25a stores the digital signal output from the A/D converter 21 in synchronization with the address output from the counter circuit 22. At this time, the index sensor 18 has already been
From then on, a new pulse is output and a second cycle is started. Now, assume that the paper sheet detection means 15 detects a banknote in the middle of the second cycle (b). In this case, the write control circuit 24 controls the first displacement amount storage means 2.
A high level write control signal is output to 5a.

Now, it is assumed that dust was attached to the surface of the banknotes conveyed in the second cycle. In this case, the displacement detection means 13 detects this dust and the A/D converter 21
A digital signal (a bill waveform and a waveform indicating dust) as shown in FIG. 5(H) is outputted from (C). When this dust adheres to the roller, in the third cycle,
After the bill is conveyed, as shown in FIG. 5(H), the level does not become low and a waveform corresponding to dust appears (d). At this time, the digital signal output from the A/D converter 21 is stored in the second displacement storage means 25b. Therefore, a digital signal (e) as shown in FIG. 5(J) is stored and simultaneously output to the subtraction circuit 26. At this time, since the subtraction circuit 26 calculates the difference between the digital signals output from the first and second displacement storage means 25a and 25b, a waveform (f) as shown in FIG. 5(K) is output. Ru. The comparison means 28 compares the digital signal output from the subtraction circuit 26 with the reference value stored in the displacement reference value storage means 27.

As a result, since the output of the subtraction circuit 26 is not at low level (zero), the comparing means 28 outputs a low level comparison signal (g). When the determination means 29 recognizes that the comparison signal is at a low level, it notifies the clerk that there is an abnormality in the conveyance of the banknotes, and at the same time strictly checks the thickness of the banknotes, mainly for banknotes to which tape or the like has been pasted. Operations that require determination will be discontinued. For example, in an automatic cash deposit/withdrawal device, the operation mode is such that deposit processing is stopped and only withdrawal processing is performed.

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 recording paper from copying machines, printers, etc. Further, the movable roller 12 does not necessarily have to be configured to transport one banknote in one rotation, but may be configured to transport one bill several times or once.
It doesn't matter if it is less than the rotation. In this case, the pulse periods output by the low-resolution encoder 17 and 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 detected based on the pulses of the row encoder 17. The displacement amount storage means 25 is not limited to a configuration that stores the displacement related to the rotation of the movable roller 17 required to convey one or two 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 recognize that foreign matter such as dust has adhered to the rollers, so that countermeasures such as cleaning the rollers etc. can be promptly taken. can be taken. Furthermore, it is also possible to continue using measures that do not involve identifying paper sheets pasted with tape or the like.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the paper sheet thickness detection device of the present invention, and FIG. 2 is an operation explanatory diagram of a conventional optical paper sheet thickness detection device.
FIG. 3 is an explanatory diagram of the operation of a conventional mechanical paper sheet thickness detection device, FIG. 4 is a perspective view of the main part of the paper sheet thickness detection device of the present invention, and FIG. 5 is a paper sheet thickness detection device of the present invention. FIG. 3 is a waveform chart showing the operation of the similar thickness detection device. 11...Fixed roller, 12...Movable roller, 13.
...Displacement amount detection means, 15...Paper sheet detection means, 17
... rotary encoder, 8 ... index sensor, 1 ... A/D converter, 22 ... counter circuit,
3...Delay circuit, 24...Write control circuit, 5...
・Displacement amount storage means, 6... Subtraction circuit (roller outer diameter change detection means), 7...
- Displacement reference value storage means, 28... Comparison means, 9...
Judgment means.

Claims (1)

[Scope of Claims] A fixed roller, a movable roller that clamps paper sheets together with the fixed roller and transports the paper sheets, and that moves according to the thickness of the paper sheets. , displacement detection means for detecting the displacement amount of the movable roller and outputting a displacement signal; and at least before nipping the paper sheet, the movable roller rotates necessary from the start of conveyance to the end of conveyance of the paper sheet. displacement amount storage means for storing the displacement signal outputted by the displacement amount detection means during the period of time; and after the movable rollers nip and convey the paper sheet, the displacement signal outputted from the displacement amount detection means and the A roller outer diameter change detection means detects a difference from the displacement signal stored in the displacement amount storage means, and the detection result by the roller outer diameter change detection means is compared with a separately set reference value, and based on the comparison result, A banknote thickness detecting device comprising: a determining means for determining whether conveyance of the paper sheet is operating normally.