JPH0672594A - Paper sheet detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a paper sheet detecting apparatus which can detect paper, sheet by means of precise paper sheet detection characteristics by installing a standard plate provided a reflecting surface on which black areas are dispersed and arranged an equal intervals in conveying direction on a white base, on a conveying route of paper sheet to be conveyed by a conveying means. CONSTITUTION:A paper sheet detecting apparatus to detect paper sheets 1 consists of a conveying route 2, a light source 3, a standard plate 4, a sensor 5, an AGC circuit 6, an amplifier 7, a discrimination unit 8 and a passing detector 9. When black areas (oblique lines) are dispersed and arranged on a white base at equal intervals in conveying direction, on the reflecting surface of a standard plate 4 in use, S/N ratio is improved, and also a sensor 5 can receive reflected light quantity of the whole body in which white areas and black areas are mixed. As soon as tips of the paper sheets 1 begin to pass on the standard plate 4 and the reflected light quantity changes partially, detected signal of the sensor 5 changes immediately and the reflected light quantity change owing to the paper sheets 1 can be detected precisely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper sheet detecting apparatus for detecting paper sheets conveyed on a conveying path.

[0002]

2. Description of the Related Art In general, a detecting device is provided for detecting a sheet conveyed on a conveying path by using a reference plate.

In order to detect a paper sheet to be detected, such a detection apparatus includes a reference plate provided on a conveying path, which irradiates light from a light emitting element with reflected light obtained from the reference plate. Light is received at, and an output level from the light receiving element at this time is used as a reference value to provide an AGC (automatic gain control) circuit to keep it constant, and the AGC circuit is turned off when a conveyed sheet passes through the reference plate. Then, there is a known one which detects a paper sheet by a variation characteristic (from a reference value) of the output of the light receiving element in which the reflected light is changed by the passage of the paper sheet on the reference plate.

Here, when the reference plate that reflects the light from the light emitting element is white, the amount of the reflected light is larger than the amount of the reflected light of the paper sheet to be detected, so that the signal-to-noise ratio (S / N ratio) becomes worse. Will end up. Further, it is possible to make the reference plate gray in order to improve the S / N ratio, but it was difficult to make a reference plate which was gray and had a certain amount of reflected light.

Therefore, as shown in FIG. 4, by using a reference plate in which a part is black (hatched part) and the rest is white, the light emitted from the light emitting element as shown in part a is black and white. The amount of light reflected from the reference plate is reduced by obtaining the amount of light reflected from the portion, and the S / N ratio is improved.

However, with such a reference plate, even if the amount of reflected light fluctuates due to the paper sheets when the conveyed paper sheets start to pass through the black portion, the amount of reflected light at the black portion is originally small. Since there is no light receiving element, the output fluctuation from the reference value of the light receiving element cannot be detected, and there is a drawback that an accurate detection characteristic of paper sheets cannot be obtained.

[0007]

As described above, when the amount of reflected light from the reference plate that reflects the light from the light emitting element is larger than the amount of reflected light of the paper sheet to be detected, the signal-to-noise ratio (S / Since the N ratio) becomes worse, the S / N ratio is improved by using a reference plate in which a part of the black color and the rest is white color. However, with such a reference plate, the amount of reflected light at the black portion was originally very small in comparison with the variation in the amount of reflected light at the time when the conveyed sheet started to pass through the black portion. There is a problem in that the output fluctuation from the reference value of the light receiving element cannot be detected, and accurate detection characteristics of paper sheets cannot be obtained. Therefore, an object of the present invention is to provide a paper sheet detection apparatus capable of detecting paper sheets by obtaining accurate paper sheet detection characteristics.

[0008]

A paper sheet detecting apparatus according to the present invention is provided on a conveying means for conveying paper sheets and a conveying path for the paper sheets conveyed by the conveying means, and is in a white conveying direction. A reference plate having a reflecting surface in which black portions are dispersed at equal intervals, an irradiation means for irradiating the reference plate, or a sheet conveyed on the reference plate with light, A conversion unit that receives the reflected light from the reference plate irradiated with light by the irradiation unit or the paper sheet conveyed on the reference plate and converts it into an electric signal, and an electric signal from this conversion unit is amplified. Amplification means, and control means for controlling the amplification factor of the amplification means by using an electric signal from the conversion means in order to keep the output level from the amplification means due to the reflected light from the reference plate constant as a reference value. , The paper is conveyed on the reference plate by the conveying means. While stopping, the stop means for stopping the control of the control means, and the paper sheets conveyed by the conveying means pass on the reference plate on the conveying path, and the output from the amplifying means changes from the reference value. It is composed of a discriminating means for discriminating the paper sheets based on the output characteristics.

The paper sheet detecting apparatus of the present invention is provided on the conveying path of the paper sheet to be conveyed, and has a reflecting surface in which black portions are distributed in white at equal intervals in the conveying direction. A reference plate and an irradiation means for irradiating the reflecting surface of the reference plate with light;
The conversion means for receiving the reflected light from the reference plate irradiated with the light by the irradiation means and converting it into an electric signal, the amplification means for amplifying the electric signal from the conversion means, and the output level from the amplification means In order to keep it constant as a reference value, it comprises a control means for controlling the amplification factor of the amplification means by using the electric signal from the conversion means.

[0010]

According to the present invention, the S / N ratio of the conveyed paper sheets is
In order to improve the ratio, irradiate light on a reference plate that has a reflecting surface in which black portions are distributed in white at equal intervals in the transport direction so that the output when the reference plate is reflected is kept constant. In addition, the detection characteristic of the paper sheet conveyed by the reflecting surface of the reference plate can be accurately obtained, and the output at the time of reflection of the reference plate and the accurate detection characteristic can be used to accurately determine the paper sheet. It is the one.

According to the present invention, the S for the conveyed paper sheets is
In order to improve the / N ratio, a reference plate having a reflecting surface in which black portions are distributed in white at equal intervals in the transport direction is irradiated with light, and the reflected light is received to convert the light. The electric signal is converted into an electric signal by means of the amplifying means, and the electric signal is amplified by the amplifying means, and the amplification factor of the amplifying means is controlled by using the electric signal so that the output when the reference plate is reflected is kept constant.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the schematic construction of an embodiment of the paper sheet detecting apparatus of the present invention. That is, the paper sheet detection device for detecting the paper sheet 1 includes the conveyance path 2, the light source 3,
Reference plate 4, sensor 5, AGC (automatic gain control) circuit 6,
It is composed of an amplifier 7, a discriminator 8, and a passage detector 9.

The paper sheet 1 is configured to be transported along the transport path 2 by, for example, a transport belt (not shown).
A reference plate 4 that reflects the light from the light source 3 and a sensor 5 that detects the amount of reflected light from the reference plate 4 or the passing paper sheet 1 are provided on the transport path 2.

The AGC circuit 6 controls the amplification factor of the amplifier 7 so that the output from the sensor 5 that receives the light emitted from the light source 3 and reflected by the reference plate 4 is kept constant. The amplification factor of the amplifier 7 is controlled by the AGC circuit 6, and the detection signal from the sensor 5 is amplified and output to the determination unit 8. The discriminating unit 8 discriminates the paper sheet 1 conveyed by the amplified signal from the amplifying unit 7.

The passage detector 9 is provided with detectors 10a and 10b, which are each composed of a light emitting element and a light receiving element, in front of and behind the reference plate 4, and detects the paper sheet 1 being conveyed.
The control operation of the AGC circuit 6 is turned on / off by the detection by 0a and 10b.

FIG. 2 shows the reflecting surface of the reference plate 4 used in this embodiment, in which black portions (hatched portions) are distributed in white at equal intervals in the carrying direction. With this configuration, the S / N ratio is improved, and the sensor 5 can receive the reflected light amount as a whole by mixing the white portion and the black portion.

As a result, when the front end of the paper sheet 1 begins to pass over the reference plate 4 and the fluctuation of the reflected light amount partially starts,
It is possible to obtain the output of the sensor 5 that accurately responds to the partial variation.

Next, the operation of detecting the paper sheet 1 in such a configuration will be described. That is, the sensor 5 receives the light emitted from the light source 3 and reflected by the reference plate 4. The sensor 5 receives the reflected light and outputs a detection signal to the AGC circuit 6 and the amplifier 7.

The AGC circuit 6 controls the amplification factor of the amplifier 7 so as to keep the output Va of the amplifier 7 constant as shown in FIG. That is, the output Va of the amplifier 7 at the time of irradiation of the reference plate 4 is always set as a reference value. Next, when the paper sheet 1 is conveyed on the conveyance path 2, the passage detection unit 9 turns off the control operation of the AGC circuit 6 when the detector 10a detects the conveyed paper sheet 1.

When the tip of the paper sheet 1 starts to pass over the reference plate 4, the output of the amplifier 7 starts to change due to the change in the reflected light by the paper sheet 1 as shown at point A in FIG. When the trailing edge of the paper sheet 1 has finished passing over the reference plate 4, the change in the output of the amplifier 7 is finished as shown at point B in FIG. The discrimination unit 8
The type of the paper sheet 1 that has passed is determined based on the output characteristics (detection characteristics) from the amplifier 7 from points A to B in FIG.
The passage detecting unit 9 turns on the control operation of the AGC circuit 6 when the detector 10b detects the passage end of the conveyed paper sheet 1.

As described above, according to the above embodiment,
The white portion of the reflecting surface of the reference plate is distributed with black portions at equal intervals in the transport direction to improve the S / N ratio, and the sensor measures the amount of reflected light as a whole in which the white portion and the black portion are mixed. By receiving light, the detection signal of the sensor changes as soon as the tip of the paper begins to pass over the reference plate and there is a partial change in the amount of reflected light, and the change in the amount of reflected light due to the paper is accurately detected. can do.

Although one light source is used in the above embodiment, a plurality of light sources may be used. For example, by turning on the red light source and the green light source and extracting and determining the detection signals of the red reflected light and the green reflected light, it is possible to detect the paper sheet more accurately. The point is that the paper sheets can be accurately detected.

[0024]

As described above in detail, according to the present invention,
It is possible to provide a paper sheet detection apparatus capable of detecting paper sheets by obtaining accurate paper sheet detection characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a paper sheet detection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a reference plate of this embodiment.

FIG. 3 is a diagram showing a change in output from an amplifier.

FIG. 4 is a diagram for explaining a conventional reference plate.

[Explanation of symbols]

1 ... paper sheets, 2 ... conveyance path, 3 ... light source, 4 ... reference plate, 5 ...
Sensor, 6 ... AGC (automatic gain control) circuit, 7 ... Amplifier, 8 ... Discrimination unit, 9 ... Passage detection unit, 10a, 10b ... Detector.

Claims (2)

[Claims] 1. A transporting means for transporting paper sheets, and a reflection provided on a transporting path of the paper sheets transported by the transporting means, in which black portions are distributed in white at equal intervals in a transport direction. A reference plate having a surface, an irradiation unit for irradiating the reference plate or a sheet conveyed on the reference plate with light, and a reference plate irradiated with the light by the irradiation unit, or this reference plate A conversion means for receiving the reflected light from the paper sheets conveyed on the plate and converting it into an electric signal, an amplification means for amplifying the electric signal from the conversion means, and the amplification by the reflected light from the reference plate. In order to keep the output level from the means constant as the reference value, the control means for controlling the amplification factor of the amplifying means using the electric signal from the converting means, and the paper sheet by the conveying means on the reference plate. A stop to stop the control of the above control means while being transported. Stopping means, and a discriminating means for discriminating the paper sheet by the output characteristic that the paper sheet conveyed by the conveying means passes on the reference plate on the conveying path and the output from the amplifying means changes from the reference value. A paper sheet detection device comprising: 2. A reference plate, which is provided on a conveyance path for conveyed paper sheets and has a reflecting surface in which black portions are distributed in white at equal intervals in a conveyance direction, and a reference plate of the reference plate. Irradiating means for irradiating the reflecting surface with light, converting means for receiving the reflected light from the reference plate irradiated with light by the irradiating means and converting it into an electric signal, and an amplifying means for amplifying the electric signal from the converting means. Means and a control means for controlling the amplification factor of the amplifying means by using an electric signal from the converting means in order to keep the output level from the amplifying means constant as a reference value. Paper sheet detection device.