JPS5960591A - Sheet paper discriminator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed explanation of the invention] (1) The present invention of the technical field of invention is the automatic payment machine, the automatic salary awe, and self! The present invention relates to an Asahi paper leaf sorting device that distinguishes paper sheets (mainly banknotes) used in assistant transaction devices and the like.

(2) Background of the technology Normally, paper sheets such as banknotes and checks are distinguished by detecting the change pattern of the transmitted light component of the medium. A light sensor consisting of a light-emitting element and a light-receiving element facing each other is provided on the conveyance path, and the sensor output is first converted and digitally processed.

In this case, it is important to carry out processing that absorbs dirt on the transport path of the optical sensor and fluctuations in the circuit system in order to determine the crystal precision.

(3) Prior art and problems A conventional paper sheet identification device uses an optical sensor consisting of a light emitting element and a light receiving element, which face each other on a conveyance path for conveying the medium.
A medium sensor provided near this optical sensor, and )゛C
It includes an AGC (self-gain control) circuit that converts the sensor output into a stable output, an A/D converter that converts the AGC circuit output into A/D, etc. ◎ However, in the conventional type described above, it is not possible to prevent component changes Wm in the AGC circuit and circuit changes *b at the downstream stage of the AGC circuit, and therefore, the optical sensor output is not stable when the medium passes through, and the medium As the moving speed increases, the pattern of the medium becomes
There were problems such as the C circuit output being unable to follow.

(4) Purpose of the Invention The first object of the present invention is to fix the gain of the variable gain amplifier provided for the optical sensor output only when there is no medium by automatic control (AGC) using the A7Di conversion output. Based on this idea, the purpose is to correct the overall fluctuation from the optical sensor to the converter and stabilize the optical sensor output when the medium passes through.

The second object of the present invention is to average the optical sensor output for a predetermined period using an integrating circuit, and then convert this average value into A/I) without reducing the medium moving speed.
The purpose is to reduce the burden of D conversion and, by extension, the burden of data processing.

(5) Structure of the Invention In order to achieve the above-mentioned object, the present invention provides an optical sensor consisting of a light emitting element and a light receiving element facing each other on a conveyance path for conveying paper sheets, and a light sensor provided near the optical sensor. a medium sensor for detecting the presence of the medium;
In a paper sheet identification device that performs Mo conversion processing on the output of the optical sensor when the medium passes through to identify the medium,
A variable gain amplifier for amplifying the output of the optical sensor, a sample hold circuit for holding the output of the variable gain amplifier, and an output of the sample hold circuit.
A Φ converter and a gain adjustment means for adjusting the gain of the variable gain amplifier are provided, and the gain adjustment means adjusts the output level of the variable gain amplifier to a predetermined value only when the medium sensor determines that there is no medium. value or within a specified range.
There is provided a paper sheet discrimination device whose function is to adjust the gain of the variable gain amplifier.

(6) Examples of the invention Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a typical automatic teller machine.

In Figure 1, 1 is a passbook Zorinta, 2 is an automatic deposit machine,
3 is a card league, 4 is a cash dispenser, and 5 is a keyboard.

The interior of the automatic teller machine of FIG. 1 is shown in FIG. That is, banknotes are fed into the input unit 2 from the entrance 1, and the input unit 2 feeds out the banknotes one by one to the banknote validating device 3, where the banknotes are validated.

Banknotes that have been successfully verified are stored in a store section 4, and banknotes that have been poorly verified are temporarily stored in a pool section 5.

Store? Il! Paper 4 'J (f) is stored in the canister 6 after the customer operates the confirmation button, but if the customer operates the cancellation button 7 instead of the confirmation button, it will be returned from the return lower. 5 banknotes are also returned from the return lower.

When paying cash, the banknotes stored in the canister 6 are fed out, separated one by one by the banknote discrimination device f113, stored in the temporary pool VA5, and then sent out all at once from the return lower. S) 1-ru.

FIG. 3 is a schematic diagram showing the inside of the banknote validating device R shown in FIG. 2. As shown in FIG. 3, a large number of conveyance rollers 32 are provided on the medium conveyance path 31 to convey banknotes. Referring to FIG. 4, the discrimination section includes, for example, the light sensor light emitting element 33 (33') and the light sensor receiving element 34.
(34') and a medium/vehicle sensor 35 provided near the optical sensor, and the signals obtained from these two sensors are shown in Fig. 3. It is processed in a system 71141 section 35 consisting of a printed board rack.

Note that the medium sensor 35 does not need to be an optical sensor and may be another type.

FIG. 5 is a block circuit diagram showing one embodiment of the paper sheet (banknote) discrimination device according to the present invention. In FIG. 5, the output of the photosensor light receiving element 34 is applied to a variable gain amplifier 52 via a preamplifier 51, where it is voltage amplified. The variable gain amplifier f52 includes one operational amplifier and an analog switch for selecting a plurality of resistors that determine the gain, and the gain setting counter 53 controls this analog switch. Also, the inversion gain an f5
2 gain control (3) jl i.e. gain setting counter 53
As will be described later, this control is performed only when it is determined from the output S of the medium sensor 35 that there is no medium.

5.4c is an integrating circuit, which is reset by a reset signal R8T2 every predetermined period. That is, the integrating circuit 54c forms the average output of the variable gain amplifier 52 for the predetermined period 4a.

Reference numeral 55 denotes an analog multiplexer, which selects either the J-sampler 54b1 which amplifies the output of the amplifier f52 by a constant amplification rate or the filter 1- of the output from the amplifier f52, and connects it to the integrating circuit 54c. The selection of both by the 0 multi-luxurer 55, which is the one to do, is 1li1. l?
I! ! It is controlled by I sword change No. 43 from 1 circuit 58. That is, the multiplexer 55 selects the direct output from the gain amplifier 53 according to the medium-free detection signal S from the sensor 35, and also selects the direct output from the gain amplifier 53 when the medium 1jjy is output.
The output from the amplifier 53 via Jj is selected via Jj. 1
This amplifier 54b is for compensating the level of the amplifier f52 output when the medium passes through.

The output of the Sansol hold circuit 56 is ADD-converted by a 2-inverter converter 57 and supplied to a control circuit 58 .

The control circuit 58 performs discrimination processing, that is, discrimination of the authenticity of banknotes and discrimination of denominations, using the change pattern of digital values.

Next, we will discuss the operation of the wholesale circuit shown in FIG.
GC) will be explained using the timing diagrams of FIGS. 6(A) to 6(D).

As shown in FIG. 6(A), when the output S of the medium sensor 35 changes from a high level to a low level and it is determined that there is no medium, the control circuit 58 sends a reset signal R8Tl as shown in FIG. 6(B). is generated, the gain setting counter 53 is reset, and the AGC is started. Also, Ruri control circuit 5
8 receives the selection signal as described above, switches the selection of the multiplexer 55, and supplies the output of the gain amplifier 52 directly to the subsequent integrating circuit 54c.

During AGC, in the internal circuit of the control circuit 58,
The output AD of the VD converter 57 and the required value SD are constantly compared, and the control circuit 58 generates a count-up signal UP to set the gain until AD=SD or IAD-8DI is converged within a predetermined range. Count up the counter 53 and return the profit? The gain of IA77''52 is changed.

That is, as shown in FIG. 6 (9), the count-up signal UP is generated and the value 1σ of the gain setting counter 53 becomes 0.
．． 1, 2. ...and the gain of the fli-controlled Anzoan increases, for example. As a result, A/'
If the output AD of the D converter 57 meets the above-mentioned condition, for example, AD=S
When D is satisfied (see FIG. 6C), the fljllg B circuit 58 stops generating the count up signal Up. As a result, the value of the gain setting counter 53 becomes, for example, 5.
'', the gain of the gain amplifier 52 is fixed, and one AGC is completed.This gain setting operation is performed for each medium in the pigeon coop where the medium is continuously transported. Needless to say, the process ends in a time sufficiently shorter than the passing interval time.

In this way, by performing AGCi only when there is no medium, the overall fluctuation from the optical sensor 33 to the A/D converter 57 is corrected, and the optical sensor output is stabilized when the medium passes. It is useful for

Next, regarding the operation timing of the sample hold circuit 56 and zero converter 57 in FIG. 5, FIGS.
), will be explained with reference to FIGS. 8-(C).

First, the analog multiplexer 55 has a variable gain of 1! The direct output of Ianf52 is selected and the proportional division circuit 54c'i5
It is assumed that the sample and hold circuit 56 is connected to the sample hold circuit 56 via the sample hold circuit 56. That is, it shows "2 cases without a medium." In this one match,! ! The i control circuit 58 generates a relatively fast sample and hold signal HLD, as shown in FIG. 7(A), and causes the sample and hold circuit 56 tlJ+ to be generated. Therefore, ~
The width change/expand operation command signal ADR of the Φ converter 57 is also shown in FIG.
As shown in Bi, it becomes relatively fast. The output AD of the ADD converter 57 at this time is the AGC! when there is no medium as described above. i
This is used for tI+ production.

On the other hand, when the medium is passed through, the analog multiplexer 55 selects the output of the amplifier 54b and the proportioning circuit 5
If the sample and hold circuit 5f) K is connected through 4c, the sample and hold signal HLD and A/
The timing of the D conversion operation command signal ADH is determined by the cascade circuit 54.
according to the timing of the reset signal R8T2. In other words,
As shown in FIG. 8(A), the reset signal R8T2 has a relatively long timing, and therefore, as shown in FIG. 8(B),
As shown in (C), the timing of the signals HLI) and AI)H also becomes longer. The timing of this reset signal -gR3T2 is determined by dividing the u body into multiple zones in advance, and
It is generated in order to calculate the integral output of the rj- integrating circuit 54 by 30°.

Conventionally, the output of the sensor 34 is scanned at regular intervals, and the average value for each zone of the medium is determined. Therefore, in order to improve the discrimination accuracy, it is necessary to reduce the sample interval, and as a result, the demand for higher speed control circuits has been met. However, as in the actual saturation case, the apportioning circuit 54
By introducing this, the sensor output accuracy for each zone will be quieter and it will be more resistant to noise. Furthermore, the load on the converter is reduced and therefore the negative phase of subsequent data processing is also eliminated.

In the circuit shown in FIG. 5, the current is fixedly connected to either the terminal output of the multiplexer 55 or the output of the amplifier f52 or the amplifier 0 output via the amplifier 54b.

(7) According to the present invention as described in detail, the medium passage +1;'i
By introducing the summing circuit 54, it is possible to stabilize the optical sensor output of the A/I converter. Negative 4[, I's 1 child translation/MotototLru.

[Brief explanation of drawings]

Figure 1-m Overview diagram showing a general automatic teller machine, 2nd
Figure 3 shows the inside of the automatic teller machine shown in Figure 1; Figure 3 shows the inside of the bill validator shown in Figure 2;
FIG. 5 is a block circuit diagram showing an embodiment of the paper sheet discrimination device according to the present invention, and FIG. 6 (A
) to (D), Figure 7 (A), ([3), Figure 8 (
A) to (C) are timing diagrams for explaining the operation of the control circuit of FIG. 5. 33... Light emitting element, 34... Light receiving element, 35...
Medium sensor, 52... variable gain amplifier, 53... gain setting counter (gain adjustment means), 54c... 41.
Branch circuit, 55...Analog multiplexer, 56...
・Sample hold circuit, 57...A/l) converter,
58...control circuit. 51 no 1 []

Claims (1)

[Claims] 1. An optical sensor consisting of a light-emitting element and a light-receiving element facing each other on a conveyance path for conveying a paper sheet medium, and a medium provided near the t-sensor for detecting the presence of the medium. a variable gain amplifier for amplifying the output of the optical sensor; and a sample/rehold circuit for bolding the output of the variable gain amplifier, an A/D converter for the output of the sample bold circuit, and gain adjustment means for adjusting the gain of the variable gain amplifier, The gain adjusting means adjusts the gain of the variable gain amplifier so that the output level of the N-converter becomes a predetermined value or within a predetermined range only when the medium sensor is determined to have no medium. Features: Paper leaf identification device. 2. An integrating circuit for integrating the output of the variable gain amplifier for a predetermined period is provided between the retrograde gain amplifier and the sample hold circuit, and the first range of t1 is calculated by 5'.
The paper sheet identification device described in . 3. An analog multi-solelexer for selectively connecting the output of the integrating circuit and the output of the variable gain amplifier to the sample and hold circuit; and (1) an analog switch is provided. The paper making device described in .