JP2001126108A - Device for identifying paper money - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the adjustment man-hour in the manufacturing process of a a device for identifying paper money. SOLUTION: A digital to analog converting means connected between the output of a controlling means and the input of a logarithmic amplifier circuit is provided, the controlling means controls the logarithmic amplifier circuit so as to make an output of the logarithmic amplifier circuit to be a preliminarily defined value when a light emitting element is made to emit light and the output value is stored in a sensor adjustment value storing means in an adjustment mode. Also, the logarithmic amplifier circuit is controlled by the output value stored in the sensor adjustment value storing means at a time when the output of a light receiving means is read and the output of the light receiving element is subsequently read. Thus, it is possible to reduce the adjustment man-hour.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bill validator for use in vending machines and the like.

[0002]

2. Description of the Related Art In recent years, with the diversification and increase in the price of products sold by vending machines, vending machines equipped with a bill validator are increasing. Vending machines are often installed outdoors, and are required to have excellent bill authenticity judgment ability.

[0003] A conventional bill validator will be described below with reference to the drawings. FIG. 5 is a block diagram of a conventional bill validator. In FIG. 5, reference numeral 81 denotes a bill to be discriminated, and reference numeral 82 denotes an entrance sensor for detecting that the bill 81 has been inserted into the insertion slot. Reference numeral 85 denotes a transport unit configured by a belt that transports banknotes.
(Motor) 86 for driving the paper currency, detecting means 87 for detecting the transport amount of the bill 81, and an optical sensor 83 composed of a red light emitting diode 83a and a photodiode 83b for detecting an optical print pattern of the bill 81. And an optical sensor 84 composed of an infrared light emitting diode 84a and a photodiode 84b, and logarithmic amplifier circuits 88 and 89 for logarithmically amplifying output signals of the optical sensors 83 and 84, respectively.
And analog-to-digital conversion means (hereinafter A) for converting the output signals of the logarithmic amplifier circuits 88 and 89 into digital quantities.
/ D conversion means) 90, a reference value storage means 91 storing the measurement position of the bill 81 and its allowable range data.
Discriminating means 92 for discriminating a bill based on an output signal of the A / D converting means 90, an output signal of the detecting means 87, and an output signal of the reference value storing means 91;
2 and a control means 93 for controlling the transport means 85 in accordance with the output signal.

The output signal of the A / D conversion means 90 used for discrimination by the discriminating means 92 discriminates a bill by using the characteristic data of a predetermined bill position of the conveyed bill 81. .

FIG. 6 is a block diagram of a logarithmic amplifier circuit and a peripheral circuit of an optical sensor of a conventional bill discriminating apparatus. 6, reference numeral 88 denotes the logarithmic amplifier circuit described with reference to FIG. 83a is a red light emitting diode, 83b
Is a photodiode. A transistor 94 is used as a logarithmic element, and forms a logarithmic amplifier circuit by utilizing the characteristic that the base-emitter voltage VBE3 of the transistor 94 is logarithm of the collector current Ie. 95 is a diode-connected transistor,
Reference numeral 96 denotes a current limiting resistor that allows a base current to flow through the transistor 95. Reference numeral 97 denotes a variable resistor for adjustment for making the output of the logarithmic amplifier circuit uniform when there is no bill. 98 is an operational amplifier for generating VBE3 in the transistor 94, and 99 is ΔΔ generated in the transistors 94 and 95.
VBE = VBE3-VBE4 is an operational amplifier for amplifying VBE4.

In the logarithmic amplifier circuit configured as described above,
The current flowing through the photodiode 83b is defined as the collector current Ie of the transistor 94, and the operational amplifier 9
8, VBE3 is generated at the emitter of the transistor 94, and a reference current is supplied to the transistor 95 by the current limiting resistor 96 to generate VBE4.
= VBE3-VBE4 was amplified by the operational amplifier 99 to obtain a logarithmic conversion output. That is, the photodiode 83 depends on the presence / absence of banknotes or the density of printing.
The banknote is determined based on the logarithmic change of the current Ie flowing through the banknote b.

The logarithmic amplifier 89 connected between the photodiode 84b and the A / D conversion means 90 performs the same processing for infrared information. The adjustment is carried out in order to eliminate variations in the sensitivities and mounting states of the optical sensors 83 and 84 in the manufacturing process.
Is adjusted by the variable resistors 97 and 97a to make the identification accuracy uniform.

[0008]

However, in such a conventional configuration, it is necessary to adjust the variable resistors 97 and 97a in the manufacturing process due to variations in the sensitivity and mounting state of the two types of optical sensors 83 and 84. was there.

The present invention has been made to solve such a problem, and has as its object to reduce the number of adjustment steps in the manufacturing process.

[0010]

In order to achieve this object, a bill discriminating apparatus according to the present invention comprises a digital-to-analog converting means connected between an output of a control means and an input of a logarithmic amplifier circuit. In some cases, the control means controls the logarithmic amplifier circuit so that the output of the logarithmic amplifier circuit becomes a predetermined value when the light emitting element emits light, and stores the output value in the sensor adjustment value storage means. And at the time of bill discrimination, when reading the output of the light receiving element, read the output of the light receiving element after controlling the logarithmic amplification circuit with the output value stored in the sensor adjustment value storage means. .

Thus, the number of adjustment steps can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is provided with a bill insertion slot, a passage connected to the rear of the insertion slot, and a passage facing one face of the bill in the passage. Light-emitting element, a light-receiving element provided on the other side of the bill so as to face the light-emitting element, control means for causing the light-emitting element to emit light, and a logarithmic amplifier circuit in which the output of the light-receiving element is directly logarithmically amplified. Analog-to-digital conversion means to which the output of the logarithmic amplifier circuit is connected, and discrimination means for discriminating the inserted bill with an output from the analog-to-digital conversion means and an output from the reference value storage means, Digital-to-analog conversion means connected between the output of the control means and the input of the logarithmic amplifier circuit, and during adjustment, when the light emitting element emits light, the output of the logarithmic amplifier circuit is predicted. The control means controls the logarithmic amplification circuit so that the output value is stored in the sensor adjustment value storage means so that the output value of the light receiving element is read when the bill is determined. A bill discriminating device that reads the output of the light receiving element after controlling the logarithmic amplifier circuit with the output value stored in the sensor adjustment value storage means. The control unit controls the logarithmic amplifier circuit so that the output of the logarithmic amplifier circuit becomes a predetermined value and stores the logarithmic amplifier circuit in the sensor adjustment value storage unit, so that the number of adjustment steps can be reduced.

Further, since the logarithmic amplifier circuit is used for the amplifier circuit, even if there is a large input fluctuation, amplification can be performed without distortion, and accurate identification can be performed.

According to a second aspect of the present invention, the sensor adjustment value storing means is the bill identifying apparatus according to the first aspect, wherein the sensor adjustment value storage means is formed of a non-volatile memory. If the adjustment is performed, it is not necessary to perform the adjustment again, and the adjustment man-hour can be reduced.

According to a third aspect of the present invention, there is provided a light emitting device having a plurality of light emitting devices having different wavelengths and being arranged close to each other. 2. The bill discriminating apparatus according to claim 1, wherein the intermittent light emission is performed alternately by the control means. Since the number of light receiving elements is one, the number of logarithmic amplifier circuits connected to the light receiving elements may be one, thereby reducing the number of adjustment steps. Can be.

Further, since only one light receiving element and one logarithmic amplifier circuit connected to the light receiving element are required, the number of circuit components can be reduced, and the size and cost can be reduced.

In the case of measuring data at the same position of a bill, two light receiving elements are provided at different positions as in the related art even if the bill slips because the light receiving element is constituted by one. In comparison with the above, since the measurement can be performed with less influence of the slip and with high accuracy, the identification performance can be improved.

Further, since the plurality of light-emitting elements emit light intermittently, it is possible to prevent the brightness of the light-emitting elements from lowering in brightness and to improve the durability of the product as compared with continuous lighting.

The light emitting device according to the present invention is formed of a red light emitting diode and an infrared light emitting diode, and a current limiting resistor forming a logarithmic amplifier circuit is for the red light emitting diode and the infrared light emitting diode. The bill recognition device according to claim 3, wherein the red light emitting diode and the infrared light emitting diode have different emission luminances but have independent current limiting resistors, so that the adjustment accuracy is improved. Adjustment is facilitated as well.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the bill validator of the present invention. In FIG. 1, reference numeral 1 denotes a bill to be discriminated, and reference numeral 2 denotes an entrance sensor for detecting that the bill 1 has been inserted into the insertion slot. Reference numeral 4 denotes a transport unit constituted by a belt for transporting the banknotes. A driving unit (motor) 5 for driving the transport unit 4, a detecting unit 6 for detecting a transport amount of the banknote 1, and an optical unit Optical sensor 3 composed of a red light emitting diode 3a, an infrared light emitting diode 3b, and a photodiode 3c for detecting a simple print pattern, and a logarithmic amplifier circuit 7 for logarithmically amplifying an output signal of the optical sensor 3
Analog-to-digital conversion means (hereinafter referred to as A / D conversion means) 8 for converting an output signal of the logarithmic amplifier circuit 7 into a digital value; D / A conversion means 9), a sensor adjustment value storage means 12 composed of a nonvolatile memory for storing an adjustment value of a reference current supplied to the D / A conversion means 9, a measurement position of the bill 1, A reference value storage means 10 storing the permissible range data;
Discriminating means 11 for discriminating a bill based on an output signal of the A / D converting means 8, an output signal of the detecting means 6, and an output signal of the reference value storing means 10; Control means 13 for controlling the means 4.

The output signal of the A / D conversion means 8 used for the discrimination by the discrimination means 11 is based on the conveyed bill 1
The bill is determined by using the characteristic data of the predetermined bill position.

FIG. 2 is a block diagram of a logarithmic amplifier circuit and peripheral circuits of the optical sensor of the bill validator according to the present invention.
In FIG. 2, reference numeral 7 denotes the logarithmic amplifier circuit described with reference to FIG. 3a is a red light emitting diode, 3b is an infrared light emitting diode, and 3c is a photodiode. Reference numeral 23 denotes a transistor used as a logarithmic element. The base-emitter voltage V
A logarithmic amplifier circuit is configured using the characteristic that BE1 is a logarithm of the collector current Ic. 24 is a diode-connected transistor, 25 is a current limiting resistor for flowing a base current to the transistor 24 when selecting the red light emitting diode 3a, and 26 is a current limiting resistor when selecting the infrared light emitting diode 3b. This is a current limiting resistor that allows a base current to flow through the transistor 24. 27 is an operational amplifier for generating VBE1 in the transistor 23, and 28 is an operational amplifier for amplifying ΔVBE = VBE1-VBE2 generated in the transistors 23 and 24.

With the logarithmic amplifier configured as described above,
A current flowing through the photodiode 3c is defined as a collector current Ic of the transistor 23, and the operational amplifier 27
VBE1 is generated at the emitter of the transistor 23, and a reference current is supplied to the transistor 24 by the current limiting resistor 25 or 26 to generate VBE2.
ΔVBE = VBE1−VBE2 is amplified by the operational amplifier 28 to obtain a logarithmic conversion output. That is, the banknote is discriminated by the logarithmic change of the current Ic flowing through the photodiode 3c depending on the presence / absence of the banknote or printing density.

The method of adjusting the optical sensor in the manufacturing process of the bill discriminating apparatus configured as described above will be described with reference to the flowcharts of FIGS. 1, 2 and 3.

In order to light the red light emitting diode 3a, an LED lighting signal is output from the control means 13 to turn on the transistor 21 (31). Next, logarithmic amplifier 7
The output of the D / A conversion means 9 is divided into 256 voltages from 0 V to 5 V (hexadecimal 0
0 to FF) are sequentially supplied through the current limiting resistor 25 (32), and the A / D conversion data at that time is converted to A / D
The data is read from the D / A conversion means 8 (33), and the output of the D / A conversion means is varied until it reaches a predetermined reference value (34). A
If the output of the / D conversion means matches a predetermined reference value, the LED lighting signal from the control means 13 is cut off, the transistor 21 is turned off, and the red light emitting diode 3a is turned off.
(35). Subsequently, the output value of the D / A conversion means 9 when the A / D conversion means 8 matches the predetermined reference value is stored in the sensor adjustment value storage means 12 (36). Next, similarly, in order to light the infrared light emitting diode 3b, an LED lighting signal is output from the control means 13 and the transistor 2 is turned on.
2 is turned ON (37). Next, in order to make the identification characteristics of the logarithmic amplifier circuit 7 uniform, the output of the D / A conversion means 9 is divided into 256 voltages from 0 V to 5 V (hexadecimal 00 to FF)
) Are sequentially supplied through the current limiting resistor 26 (38), and the A / D conversion means at that time is changed to the A / D conversion means 8.
(39), and D /
The output of the A conversion means is varied (40). If the output of the A / D conversion means matches a predetermined reference value, the LED lighting signal from the control means 13 is cut off and the transistor 22 is turned off.
Then, the infrared light emitting diode 3b is turned off (41).
Subsequently, the output value of the D / A converter 9 when the A / D converter 8 matches the predetermined reference value is stored in the sensor adjustment value storage 12 (42).

The reason why the two types of current limiting resistors 25 and 26 are required is that the circuit constants are different due to the difference in emission luminance between the red light emitting diode 3a and the infrared light emitting diode 3b.

Next, the operation will be described with reference to the flowcharts of FIGS. 1, 2 and 4.

When the bill 1 is inserted, if the bill 1 is detected by the entrance sensor 2 of the insertion slot (51), a motor normal rotation signal is outputted from the control means 13 to the motor 5 (52).
Then, the conveyance belt 4 rotates forward by the power of the motor 5,
The bill 1 is guided into the passage. Subsequently, in order to turn on the red light emitting diode 3a, an LED lighting signal is output from the control means 13, the transistor 21 is turned on, and the red light emitting diode 3a is turned on (53). Next, the red light emitting diode 3a stored in the sensor adjustment value storage means 12
The D / A conversion output set value of
Output to the / A conversion means 9 (54). Next, the A / D conversion data is read until the leading end of the bill 1 reaches the optical sensor 3 (55). When the leading end of the bill 1 reaches the optical sensor 3 (56), the LED lighting signal of the control means 13 is cut off and the red light emitting diode 3a is turned off (57). Further, identification starts when the leading end of the bill 1 reaches the optical sensor 3 and data at a predetermined bill position of the bill 1 is measured by the red light emitting diode 3a or the infrared light emitting diode 3b. Do. That is, when data is measured with the red light emitting diode 3a (58), an LED lighting signal is output from the control means 13 to turn on the red light emitting diode 3a, and the transistor 21 is turned on.
Then, the red light emitting diode 3a is turned on (59).

Next, the D / A conversion output set value of the red light emitting diode 3a stored in the sensor adjustment value storage means 12 is output to the D / A conversion means 9 via the control means 13 (6).
0), and read the A / D conversion data (61). Next, the LED lighting signal of the control means 13 is cut off, and the red light emitting diode 3a is turned off (62).

When data is measured by the infrared light emitting diode 3b (63), an LED lighting signal is output from the control means 13 to turn on the infrared light emitting diode 3b, the transistor 22 is turned on, and the red light is turned on. The outside light emitting diode 3b is turned on (64). Next, sensor adjustment value storage means 1
The D / A conversion output set value of the infrared light emitting diode 3b stored in 2 is output to the D / A conversion means 9 via the control means 13 (65), and the A / D conversion data is read ( 66). Next, the LED lighting signal of the control means 13 is cut off, and the infrared light emitting diode 3b is turned off (67).

When the measurement of the bill data at the predetermined position is completed (68) as described above, a motor stop signal is output from the control means 13 to the motor 5 (69), and the motor 5 stops. Next, the characteristic data of the predetermined banknote position, which is measured for the banknote 1, and the allowable range data of the reference value storage unit 10 are compared and determined by the determination unit 11 to determine whether the banknote is a genuine or fake bill (70 )I do. If it is determined that the bill is genuine, a genuine bill signal is output (71), and the process returns to the standby state. If it is determined that the banknote is a counterfeit, a motor reversal signal is output from the control means 13, the motor 5 is reversed, the bill 1 is discharged from the passage (72), and the motor 5 is stopped (73), and then returns to the standby state. .

[0032]

As described above, according to the present invention, the logarithm is controlled by the control means so that the output of the logarithmic amplifier circuit becomes a predetermined value when the light emitting element is caused to emit light without any manual operation at the time of adjustment. Since the amplifier circuit is controlled and stored in the sensor adjustment value storage means, the number of adjustment steps can be reduced.

Further, since the logarithmic amplifier circuit is used for the amplifier circuit, amplification can be performed without distortion even if there is a large change in input, and accurate identification can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a banknote recognition device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a logarithmic amplifier circuit and peripheral circuits of the optical sensor.

FIG. 3 is a flowchart of the optical sensor adjustment mode.

FIG. 4 is a flowchart for explaining the operation of the bill discriminating apparatus.

FIG. 5 is a block diagram of a conventional bill validator.

FIG. 6 is a block diagram of a logarithmic amplifier circuit and peripheral circuits of the optical sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Banknote 3 Optical sensor 3a Red light emitting diode 3b Infrared light emitting diode 3c Photodiode 7 Logarithmic amplifier circuit 8 A / D conversion means 9 D / A conversion means 10 Reference value storage means 11 Judgment means 12 Sensor adjustment value storage means 13 Control means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Ueki 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Takema Fujiwara 1006 Odaka Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A bill insertion slot, a passage connected behind the insertion slot, a light emitting element provided to face one surface of the bill in this passage, and a bill to face the light emitting element. A light-receiving element provided on the other surface side, control means for causing the light-emitting element to emit light, a logarithmic amplifier circuit in which the output of the light-receiving element is directly logarithmically amplified, and an analog amplifier to which the output of the logarithmic amplifier circuit is connected. Digital conversion means, discrimination means for discriminating the inserted bill with the output from the analog-digital conversion means and the output of the reference value storage means, between the output of the control means and the logarithmic amplifier circuit Digital-to-analog conversion means connected to the
At the time of adjustment, the control means controls the logarithmic amplifier circuit so that the output of the logarithmic amplifier circuit becomes a predetermined value when the light emitting element emits light, and stores the output value as a sensor adjustment value storage means. At the time of bill discrimination, when reading the output of the light receiving element, the bill reading the output of the light receiving element after controlling the logarithmic amplification circuit with the output value stored in the sensor adjustment value storage means. Identification device. 2. The bill discriminating apparatus according to claim 1, wherein the sensor adjustment value storage means is formed by a nonvolatile memory. 3. A plurality of light emitting elements having different wavelengths and having a plurality of light emitting elements arranged in close proximity to each other, wherein the light receiving element is one light receiving element, and the plurality of light emitting elements are alternately intermittently controlled by a control means. The bill discriminating apparatus according to claim 1, which emits light. 4. The light emitting element is formed of a red light emitting diode and an infrared light emitting diode, and current limiting resistors forming a logarithmic amplifier circuit are independently provided for the red light emitting diode and the infrared light emitting diode. The bill discriminating apparatus according to claim 3 provided.