JPS6362790B2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an apparatus for determining authenticity of banknotes.

(Prior Art) Among automatic vending machines and the like, machines that accept not only coins but also banknotes have become widely used. Since devices that handle these banknotes handle large amounts of money, it is necessary to take countermeasures against counterfeit banknotes even more so than devices that only handle coins.
A variety of magnetic methods have been provided.

(Problems to be Solved by the Invention) Here, in order to improve the discrimination accuracy, the discrimination method should be made as complicated as possible, but this also has its own limits due to the complexity of the device configuration. In the case of optical detection, there is a method in which a light transmission amount signal is obtained by performing optical scanning along two lines in the longitudinal direction of a bill, and authenticity is determined based on the signal. This may be three or more lines, but in any case, since a circuit is configured for each scanning line, at least two sets of discrimination circuits are required. Moreover, there are four ways to insert a banknote depending on the front/back and front/back combinations of the banknote, and to accommodate these four sets of circuits would be required, which would significantly complicate the circuit configuration. .

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a bill authenticity discriminating device that can perform a discriminating operation regardless of the direction in which a bill is inserted and can perform this operation using a single circuit.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a device for conveying banknotes along their longitudinal direction;
An optical detection device that optically scans the banknote along at least two lines parallel to the transportation direction in this transportation device and detects a plurality of light transmission amount signals, and a high level signal and a low level signal among the signals from this detection device. a circuit for discriminating and extracting the signal, and an authenticity determining circuit for detecting the difference between the high level signal and the low level signal applied through this discrimination circuit, and determining the authenticity of the bill when this difference is greater than a predetermined value. , a level determination circuit that determines whether or not the high level signal has a peak value that should be indicated in the case of a genuine banknote; and an amplification detection circuit that outputs an output when the level of the high level signal increases in accordance with the pattern of the banknote. , an apparatus for determining authenticity of banknotes, comprising a circuit that determines that the bill is genuine when the authenticity determination circuit, the level determination circuit, and the increment detection circuit generate outputs at the same time, and that otherwise determines that the bill is counterfeit. This is what we provide.

(Operation) A banknote sent along the transport path of the transport device is optically scanned by an optical detection device to obtain a light transmission amount signal. This signal consists of two signals along two lines parallel to the transport direction. These two signals are discriminated by a discrimination circuit as a high-level signal and a low-level signal, and these high and low level signals are given to a difference detection circuit, and the output of this difference detection circuit is given to an authenticity determination circuit, which determines the authenticity of the banknote. False discrimination output is obtained.

Further, the high level signal is applied to a level discrimination circuit and an increment detection circuit, and it is extracted whether the high level signal has a peak value that a genuine note should have and whether it has an increment due to a genuine note, thereby further increasing the discrimination accuracy. .

(Embodiment) FIG. 1 shows a circuit configuration of an embodiment of the present invention. This circuit determines whether a banknote is genuine or fake by detecting a light reception signal when two lines parallel to the longitudinal center line of the banknote are scanned using a light transmission method. Among banknotes, by appropriately selecting the scanning position, the genuine 1,000 yen banknote currently in circulation can be inserted from any direction in the longitudinal direction, and the scanning output on two lines parallel to the longitudinal center line will be clearly visible. As a result of experiments, the inventor of the present invention found that there is a difference in that a difference occurs, whereas a difference does not occur in counterfeit notes produced by electrophotography. Since the bill is scanned by a light transmission method, the scanning output is the same whether the bill is inserted with the front or back facing up. As a result, banknotes may be inserted in any longitudinal direction.

The circuit shown in FIG. 1 is configured to perform this discrimination operation with the simplest circuit configuration. In this circuit, both LP and RP are light receiving elements, and banknote X
When the banknote is sent in the transport direction indicated by the arrow, the transmitted light is detected when light is projected from the back side of the banknote at the positions of two lines parallel to the longitudinal center line of the banknote. Light receiving element LP,
Each detection signal of RP is amplified by an amplifier AMP and given to a diode bridge circuit DB. This diode bridge circuit DB is an amplifier
It has a discrimination function that extracts the high value of outputs a and b of AMP ₁ and AMP ₂ as output c, and the low value as output d. Similarly, when optically scanning three positions on a banknote and receiving a detection signal from another light receiver, the highest value among the three signals,
Discrimination takes place in the form of detection of low values.

Of these two discriminated signals c and d, the signal c is applied to the comparator COMP ₁ , the +input terminal of the differential amplifier DA of the authenticity determining circuit, and the input terminal of the incremental detection circuit ID. Comparator COMP ₁ uses signal c as the reference value
When compared with Vth ₁ , if the signal c has a level higher than that obtained in the case of a genuine note, the output e is given to the first input terminal of the AND gate AND. Further, the differential amplifier DA supplies the difference f with the other output signal d of the bridge circuit DB to the +input terminal of the comparator COMP ₂ . Comparator COMP ₂ uses this difference signal F as the reference value.
When Vth exceeds ₂ , the truth determination output g is given to the second input terminal of the AND gate AND. In addition, in the incremental detection circuit ID, the signal c is applied to the + input terminal of the comparator COMP ₃ , while the diode D is applied to the one input terminal.
and a peak holding signal by capacitor C ₀ are applied, and the comparison output i of these two signals is applied to the third input terminal of the AND gate AND.

FIG. 2 shows signal waveforms of various parts of the circuit of FIG. 1, and the operation of the circuit of FIG. 1 will be explained below based on this waveform diagram.

First, Figure A shows signals a and b that were detected by the light receiving elements LP and RP and amplified by the amplifiers AMP ₁ and AMP ₂ when the banknote X was conveyed. There is a difference. These signals a and b pass through a diode bridge circuit DB, and a high value signal c appears at one output terminal, and a low value signal d appears at the other output terminal.

Of these two signals c and d, the signal c is first converted to the reference value Vth ₁ by the comparator COMP ₁ , as shown in FIG.
If the level is higher than that, it is judged as a genuine note, and the signal e shown in Figure C is given to the first input terminal of the AND gate AND.
If the level is lower than Vth ₁ , it will be determined that the note is counterfeit, and the input conditions for the AND gate will no longer hold true.
The comparator COMP ₁ determines whether a bill is a counterfeit bill, for example, if the bill does not have a watermark.

The signal c is also applied to the incremental detection circuit ID.
This increment detection circuit ID detects a signal when a comparator COMP ₃ compares a signal c with a signal h formed between both ends of the capacitor C ₀ by applying this signal c to the capacitor C ₀ via a diode D. c is the signal h
The comparator COMP ₃ is configured to produce an output i when it exceeds . And this comparator
The output i of COMP ₃ is generated when the banknote has a pattern similar to that of a genuine banknote, and the output i is applied to the third input terminal of the AND gate AND.

In addition, the signal c, together with the signal d, is passed through the authenticity discrimination circuit TF.
The signal f given to the differential amplifier DA and shown in FIG.
is formed and given to the comparator COMP ₂ and the reference value Vth ₂
When the note is compared with , and the note is genuine, the output g shown in FIG. The case where this output is not produced is the case of a counterfeit bill produced by the above-mentioned electrophotographic method.

As a result of these operations, if the bill is a genuine bill, the three input terminals of the AND gate AND will receive signals e, g, and i.
are given at the same time, the AND gate AND generates the signal j shown in Figure G, but if the banknote is a counterfeit banknote, one of the signals e, g, and i will be missing or the timing will be off, so the output j will not be output. .

The presence or absence of this output j is used, for example, in a vending machine to accept or refuse to accept banknotes. In other words, when the output j is given, the vending machine temporarily holds the banknotes in preparation for the next vending operation, and when the output j is not given, the refund mechanism is immediately activated to accept the banknotes. Discharge. The timing for determining whether or not a banknote can be accepted can be obtained by using the time when a banknote position detection device (not shown) detects the leading edge of the banknote, or by using the time after the banknote transport mechanism starts operating.

〔Effect of the invention〕

As described above, the present invention calculates the difference between two or more signals obtained by scanning along at least two lines parallel to the longitudinal center line of the banknote, and determines the difference between two or more signals obtained by scanning along at least two lines parallel to the longitudinal center line of the banknote. Selecting a signal, determining that its level is greater than or equal to a predetermined value, and further determining the incremental period of this high level signal,
Since the authenticity of the banknotes is determined by comprehensively evaluating these three types of determination results, it is possible to determine whether or not the banknotes are in a state that is very close to the state that is satisfied only if the banknotes are genuine. It is possible to make judgments and highly accurate determination of authenticity. Moreover, the circuit configuration for this purpose is not very complicated and can be easily configured.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a circuit configuration of an embodiment of the present invention, and FIG. 2 is a signal waveform diagram of each part of the circuit in FIG. LP, RP...light receiving element, DB...diode bridge circuit, TF...truth discrimination circuit, ID...incremental detection circuit, DA...differential amplifier, COMP...comparator.

Claims (1)

[Claims] 1. A device that conveys a banknote along its longitudinal direction; an optical detection device that optically scans the banknote along at least two lines parallel to the conveyance direction in this conveyance device and detects a plurality of light transmission amount signals; A circuit that discriminates and extracts high-level signals and low-level signals in the signal from this detection device, and detects the difference between the high-level signal and low-level signal given through this discrimination circuit, and this difference is determined by a predetermined value. an authenticity discriminating circuit that discriminates whether the bill is genuine when the high level signal is equal to or greater than the value; a level discriminating circuit that discriminates whether or not the high level signal has a peak value that should be indicated in the case of a genuine bill; When the boost detection circuit outputs an output when the level of the high-level signal increases, the authenticity discrimination circuit, the level discrimination circuit, and the increment detection circuit generate outputs at the same time, it is determined that the bill is genuine; otherwise, it is determined that it is a counterfeit bill. A device for determining authenticity of banknotes, which is equipped with a circuit for detecting banknotes.