JPH0696314A - System for correcting magnetic sensor for paper money discrimination - Google Patents

Abstract

PURPOSE:To automatically correct variation in the level of the output signal of a magneto-resistance element even if the output signal level is varied owing to the change with the lapse of time. CONSTITUTION:A rugged part is formed on the outer peripheral surface of the rotary shaft of a roller 10 which faces a magnetic sensor 11 for discriminating paper money, a magnetic detection film 16 made of a magnetic body is adhered to the outer peripheral surface, and when paper money begins to be discriminated and counted, the magnetic sensor 11 detects this magnetic pattern; and its peak value is detected and a gain arithmetic circuit 19 corrects the gain value of an amplifying circuit 13. If the correction is completed in a standby state and a shutter 6 is opened, the mode is switched to a discrimination execution mode and the pattern of the paper money is read, but the signal from the magnetic sensor 11 passes through a high-pass filter 20 to subtract a magnetic pattern signal as low-frequency components, thereby obtaining a signal regarding the pattern components of the paper money.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a banknote discriminating magnetic sensor correction system installed in a bank or other financial institution for discriminating and counting banknotes. .

[0002]

2. Description of the Related Art A bill discriminating / counting device is a hopper into which bills are inserted, a bill separating unit that separates the bills from the hopper, and a bill that is separated by the bill separating unit. And a discriminating / counting unit that is provided in the middle of the conveying unit and that discriminates the authenticity, denomination, front and back, and the presence or absence of damage of the conveyed banknotes, and that counts the bills. A stacker that stacks banknotes for each denomination based on the discrimination result in the discrimination / counting unit.

The bill discrimination in the discriminating / counting unit is performed by detecting the pattern pattern of the bill, and a magnetic sensor is used for this purpose. This magnetic sensor is composed of, for example, a permanent magnet and a pair of magnetoresistive elements, detects a magnetic substance contained in printing ink in a bill, and takes out as a change signal of the voltage output from the magnetoresistive element, and detects this. By comparing the signal with a predetermined set value, the authenticity, denomination, etc. are discriminated.

[0004]

In the magnetic sensor using the above-mentioned magnetoresistive element, the resistance value changes depending on the distance between the magnetoresistive element and the bill to be detected. Therefore, this interval is always constant. You must keep it. Further, if there is variation in the gain value of the amplifier that amplifies the output signal from the magnetoresistive element, the detection accuracy is affected.
Of course, although these parts are initially adjusted, the output of the magnetic sensor fluctuates in the long term due to changes over time. In this way, if the value fluctuates from the initial set value, the banknotes that should originally be stored in the predetermined genuine banknote stacker are rejected without being determined to be legitimate banknotes and are sent to a separately provided reject stacker. There is a problem.

The present invention has been made in order to solve the problems and drawbacks of the prior art as described above, and its purpose is to prevent the output signal from the magnetoresistive element from changing with time. Even if the level changes, the change in the output signal level can be automatically corrected.

[0006]

In order to achieve the above-mentioned object, the present invention provides a roller installed in a discriminating section with a magnetic detection member having a magnetic pattern that changes in a rotational direction detectable by a magnetic sensor. Before the bill is sent to the discriminating section, the magnetic sensor detects the magnetic detection member, compares the detection signal with the set value, adjusts the output level, and the bill is sent to the discriminating section. Thus, when performing discrimination, the feature is that the signal related to the pattern pattern component of the bill is extracted by subtracting the magnetic pattern component from the magnetic detection member from the output signal of the magnetic sensor.

[0007]

In general, in a bill discriminating / counting device, when a start button is operated to start discriminating / counting bills when the bills are inserted into the hopper, the bill conveying system in the device is first of all operated. However, the shutter provided in the banknote outlet of the hopper is kept closed for a predetermined time, and the banknotes in the hopper are corrected to a normal posture, which is a so-called standby state. The roller arranged in the discrimination section also constitutes a part of the transport system, and therefore the roller rotates even in this standby state. Since this roller is provided with a magnetic detection member having a magnetic pattern that changes in its rotation direction, the magnetic sensor detects this magnetic pattern. If this magnetic pattern is compared with the reference pattern and there is a difference between them, the output level of this magnetic sensor can be corrected, for example, by changing the gain value of an amplifier that amplifies the output signal of the magnetic sensor.

After that, the shutter provided at the exit of the hopper is opened, the bill is fed into the transport system, passes through the discrimination unit, and the magnetic sensor reads the pattern pattern printed on the bill. Thus, when the signal is output, the signal of this pattern pattern is the signal obtained by adding the magnetic pattern of the roller. Therefore, the actual pattern pattern of the bill is recognized by subtracting the magnetic pattern component from the output signal.

Thus, in this way, the bills are actually discriminated and
Since the output level of the magnetic sensor that detects the pattern pattern of this banknote is corrected every time it is counted, the accuracy of banknote detection is significantly improved, and the frequency of rejecting normal banknotes can be minimized. become.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, FIG. 1 schematically shows an overall configuration of a bill discriminating / counting device. In the figure, 1 is a hopper, 2
Reference numerals a, 2b and 2c are genuine bill stackers on which bills of different denominations are stacked, and 2d is a reject stacker. The hopper 1 is provided with a bill separating / delivering mechanism including a separating drum 3 and a pressing roller 4 at the bill discharging port 1a, and an auxiliary feeding roller 5 for smoothly feeding the bill to the bill discharging port 1a. A shutter 6 that is provided and that opens and closes the bill outlet 1a is provided. Further, a bill transport path 7 is provided in connection with the bill outlet 1a,
A discriminating / counting unit 8 is provided at an intermediate position of the bill conveying path 7. The discriminating / counting unit 8 discriminates and counts the bills, and the genuine bill stacker 2 for each denomination of the bill.
It is stacked in any of a, 2b, and 2c. Further, when it is determined that the bill is a bill other than these genuine bills, the bill is sent to the reject stacker 2d.

The discrimination / counter 8 discriminates the authenticity of bills, denomination, front and back, and the presence / absence of damage. A mechanism for performing this discrimination work is shown in FIG. As described above, the roller 10 and the magnetic sensor 11 are used. The magnetic sensor 11 is composed of a combination magnetoresistive element using a pair of magnetoresistive elements MR1 and MR2 and a permanent magnet M. When a bill passes between the magnetic sensor 11 and the roller 10, the magnetic substance contained in the printing ink of the bill moves, so that the magnetoresistive element M
An alternating resistance change occurs in R1 and MR2.
Therefore, by configuring the voltage dividing circuit 12 as shown in FIGS. 3 and 4, the resistance change caused by the movement of the magnetic body can be extracted as a voltage change. Therefore, the output signal is amplified by the amplifier circuit 13,
The / D converter 14 converts the digital signal into a digital signal, transmits the digital signal to the recognition unit 15, and performs predetermined signal processing to recognize the pattern pattern of the banknote. Then, by comparing the pattern pattern of the banknote recognized in this way with the information recorded in the recognition unit 15, it is possible to determine the authenticity and denomination of the banknote, the front and back of the banknote, and the presence or absence of damage. Identification such as inspection is performed. By the way, the magnetic sensor 11 described above is
The discrimination accuracy is greatly affected by the distance between the roller 10 and the roller 10, the amplification factor of the amplifier circuit 13, and other changes. Therefore, in the present invention, the output of the magnetic sensor 11 is constantly monitored, and when there is an output fluctuation, this fluctuation is automatically corrected.

First, a standard magnetic pattern is used to detect the output of the magnetic sensor 11. Here, as described above, the magnetic sensor 11 has a pair of magnetoresistive elements MR1 and MR2 when the magnetic body moves.
The roller 10 facing the magnetic sensor 11 is used as an object to be detected because it detects the resistance change of the roller. Thus, the roller 10 is formed by mounting the roller body 10b, which is made of a member having elasticity and a high friction coefficient such as rubber, on the rotating shaft 10a.
An uneven portion is formed on the outer peripheral surface of 0a, and the magnetic detection coating 16 made of a magnetic material is applied to the outer peripheral surface. Therefore, when the roller 10 is rotated, the distance between the magnetic sensor 11 and the magnetic detection coating 16 changes, so that the magnetic sensor 11 outputs the sine wave signal shown in FIG. become. In addition, this magnetic pattern is the roller body 10b.
It can also be formed by burying a magnetic material in a predetermined angle. Therefore, by holding the peak value of this output signal and comparing it with a predetermined set value, the presence or absence of output fluctuation of the magnetic sensor 11 is detected. When this output value is different from the set value, the level of the output signal from the magnetic sensor 11 can be corrected by adjusting the gain value in the amplifier circuit 13.

To this end, a mode changeover switch 17 is provided on the output side of the amplifier circuit 13, and the mode changeover switch 1 is provided.
7, it is possible to switch between the above-described output monitoring / correction mode of the magnetic sensor 11 and the discrimination execution mode in which bills are actually passed for discrimination. Then, a peak hold circuit 18 and a gain calculation circuit 19 are provided on the output monitoring / correction mode side, and the peak value of the output sine wave signal from the magnetic sensor 11 sent by the peak hold circuit 18 via the amplifier circuit 13 is calculated. It is possible to hold and compare the peak value thus obtained with the set value in the gain calculation circuit 19 and input a signal of the difference to the amplification circuit 13 to perform gain correction.

By the way, when a bill is passed to the position of the magnetic sensor 11 to discriminate the bill, the magnetic sensor 1 is used.
As shown in FIG. 5B, the waveform of the output signal from 1 is a combined signal of the pattern pattern of the banknote and the magnetic pattern of the magnetic detection film 16, so that the magnetic detection film 16 The pattern component must be removed. For this purpose, a high pass filter (or band pass filter) 20 is provided in front of the A / D converter 14.
Therefore, the output signal from the magnetic sensor 11 is passed through the high-pass filter 20 to subtract the magnetic pattern component described above, and as shown in (c) of FIG.
Only the pattern component of the bill can be taken out, which is converted into a digital signal by the A / D converter 14 and input to the recognition unit 15, whereby the bill is discriminated.

When a large number of banknotes are put into the hopper 1 and the start button provided on the control panel of the banknote discrimination / counting apparatus is operated, first, the separating drum 3,
The auxiliary feed roller 5 and the bill transport path 7 start operating.
However, the banknotes in the hopper 1 are not immediately sent out at the time of this start, but in order to correct the posture of the banknotes in the hopper 1 and the like, the shutter 6 is closed for a predetermined time to carry out the banknotes. No standby. Therefore,
Using this waiting time, the output of the magnetic sensor 11 is monitored and corrected. That is, when the start button described above is operated, the mode changeover switch 17 is switched to the output monitoring / correction mode, and the detection by the magnetic sensor 11 is started. Here, the roller 10 constitutes a part of the banknote transport path 7, and starts rotating at the same time when the start button is operated. Therefore, the magnetic sensor 11 detects the magnetic detection coating 16 on the roller 10 and inputs it to the peak hold circuit 18 via the amplifier circuit 13,
The peak value of the sine wave signal is detected. Then, this peak value is input to the gain calculation circuit 19 and compared with a set value. When the peak value is lower than the set value, the gain adjustment signal is composed of a gain increase signal, and when it is higher than the set value, a gain adjustment signal composed of a gain decrease signal. The signal is input to the amplifier circuit 13, and the gain value of the amplifier circuit 13 is set based on this gain adjustment signal. Therefore, the magnetic sensor 1 itself and the amplifier circuit 13
It is possible to reliably and accurately correct the output characteristic that changes depending on various states and conditions, and adjust so that the output level is always constant.

The output level is corrected in this manner, but this correction is completed while the standby state is maintained, and when the shutter 6 is opened, the mode changeover switch 17 discriminates. Switch to run mode. Then, the bill is sent to the discrimination / counter unit 8 and the pattern pattern of the bill is read by the magnetic sensor 11. The gain value of the output signal from the magnetic sensor 11 is adjusted when it is amplified by the amplifier circuit 13. By the way, this output signal is in a state in which the signal related to the pattern pattern of the bill is combined with the signal of the magnetic pattern by the magnetic detection coating 16. Therefore, this signal is first passed through the high pass filter 20 to subtract the magnetic pattern signal, which is a low frequency component,
A signal of only the pattern component of the bill is obtained. Then, the signal thus subtracted is sent to the recognition unit 15,
The bill is discriminated by comparing with the data preset in the recognition unit 15.

Since the gain value in the amplification circuit 13 is automatically corrected every time the bills are discriminated and counted, the bills can be discriminated more accurately. Therefore, the discrimination becomes impossible, and the number of bills sent to the reject stacker 2d can be suppressed to the minimum.

In the above-mentioned embodiment, the output of the magnetic sensor 11 is corrected by using the analog circuit. However, the output of the magnetic sensor 11 can be corrected by using the digital circuit shown in FIG. You can Thus, also in this case, in the output monitoring / correction mode, except that the signal converted into the digital signal by the A / D converter 25 is input to the gain calculation circuit 19 ′, FIGS. The circuit configuration is the same. Therefore, these circuit configurations are denoted by the same reference numerals as those in FIG. 4 described above, and their detailed description is omitted. However, on the discrimination execution mode side, the A / D converter 2 is connected to the output side of the mode changeover switch 17.
1 is provided, and the output signal from the A / D converter 21 is input to the subtraction unit 22 and read out to the waveform storage unit 23 of the magnetic pattern signal by the preset magnetic detection coating 16 to read out the drive signal. Enter. As a result, the waveform stored in the waveform storage unit 23 is read from the waveform storage register, and the magnetic pattern component of the magnetic detection coating 16 is subtracted from the signal sampled from the bill by the subtraction unit 22. Then, the signal relating to the pattern pattern of the bill obtained by subtracting the magnetic pattern signal in this way is transmitted to the recognition unit 15 and the bill is discriminated by the same method as in the first embodiment. It Needless to say, these circuit components can be configured by a microcomputer.

[0020]

As described above, according to the present invention, a magnetic detection member having a magnetic pattern that changes in the rotation direction that can be detected by the magnetic sensor is provided on the roller arranged opposite to the magnetic sensor, and the bill is used as the discrimination section. Before being sent,
By detecting this magnetic detection member and comparing this detection signal with a set value, the output level is adjusted, and when the bill is sent to the discriminating section and the discrimination is performed,
Since the pattern pattern of the banknote is recognized by subtracting the magnetic pattern component of the magnetic detection member from the output signal of the magnetic sensor, the output characteristics of the magnetic sensor itself and the amplification circuit that change depending on various states and conditions. Each time a discrimination is performed, it can be corrected reliably and accurately, and the actual discrimination can be executed after adjusting so that the output level is always constant, and the frequency of rejecting normal banknotes is minimized. can do.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a bill discriminating / counting device.

FIG. 2 is a structural explanatory view of a magnetic sensor showing an embodiment of the present invention.

FIG. 3 is a circuit configuration diagram for executing a correction method of the bill discriminating magnetic sensor according to the first embodiment of the present invention.

FIG. 4 is a block configuration diagram of a circuit in FIG.

5 is a waveform diagram in each part of the circuit of FIG.
(A) shows the signal waveform of the magnetic pattern of the magnetic detection member,
(B) shows a signal waveform when a bill is detected by the magnetic sensor, and (c) shows a signal waveform obtained by subtracting the magnetic pattern signal from the bill detection signal.

FIG. 6 is a block configuration diagram of a circuit for executing a correction method of a bill discrimination magnetic sensor according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Hopper 2a, 2b, 2c Straight bill stacker 2d Reject stacker 7 Banknote transport path 8 Discrimination / counter 10 Roller 11 Magnetic sensor 12 Voltage dividing circuit 13 Amplifier circuit 15 Recognition unit 16 Magnetic detection film 17 Mode change switch 18 Peak hold circuit 19 Gain calculation circuit 20 High-pass filter 21 A / D converter 22 Subtraction unit 23 Waveform storage unit

Claims (1)

[Claims] 1. A discrimination unit including a roller and a magnetic sensor having a magnetoresistive element facing the roller is provided at an intermediate position of a bill conveyance path, and the pattern pattern of the bill is recognized by the magnetic sensor. In the above, the roller is provided with a magnetic detection member having a magnetic pattern that changes in a rotation direction that can be detected by the magnetic sensor, and before the bill is sent to the discrimination unit, the magnetic sensor Detect the detection member, compare this detection signal with the set value, adjust the output level,
When a bill is sent to the discriminating section and discrimination is performed, a signal relating to the pattern pattern component of the bill is extracted by subtracting the magnetic pattern component by the magnetic detection member from the output signal of the magnetic sensor. Compensation method of magnetic sensor for bill discrimination.