JPS60222989A - Sheet papers discriminator - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a paper sheet discrimination device that determines, for example, the authenticity of banknotes.

[Technical Background of the Invention II] Conventionally, this type of paper sheet discrimination device has been used, for example, by constantly irradiating light from a light source onto a standard plate and using the reflected light (or excitation light) from the standard plate as a reference. There is a system that determines the authenticity of a banknote based on the amount of light reflected from the banknote (or the amount of excitation light) when the banknote being conveyed blocks the light from the light source. FIG. 1 shows an example of its configuration. In the figure, reference numeral 1 denotes a dark box through which banknotes P are conveyed in the direction of arrow a in the figure.

A timing generation light w2 and a light receiver 3 are provided facing each other on the bill entry side of the dark box 1. Further, approximately in the center of the dark box 1, there is a light source 4 that irradiates light onto the banknotes P to be transported, a standard plate 5 to which light from the light source 4 is irradiated when there is no banknote P, and the banknotes P to be transported and A light receiver 7 receives reflected light from the standard plate 5 via a filter 6
is provided. Therefore, when the bill P is not conveyed, the light from the light 14 is constantly irradiated onto the standard plate 5, and the reflected light from the standard plate 5 is transmitted through the filter 6 to the light receiver 7.
is guided and photoelectrically converted. Further, when the banknote P is conveyed and reaches the position of the standard plate 5, it is irradiated with light from the light source 4, and the reflected light from the banknote P is guided to the light receiver 7 via the filter 6, where it is photoelectrically converted. be done. By sending the output of this light receiver 7 to a processing circuit (not shown), the standard plate 5
The authenticity of the banknote P is determined based on the amount of light reflected from the banknote P when the banknote P being conveyed blocks the light from the light source 4 based on the reflected light from the banknote P.

[Problems with the Background Art] However, in the conventional configuration described above, the standard plate 5 is exposed on the conveying surface of the banknote P, so dust and
The amount of reflected light changes when dust or the like adheres, or due to deterioration of the standard plate 5 itself, and the amount of reflected light from the banknote P, which is detected based on the amount of reflected light from the standard plate 5, becomes unstable. There was a problem in that the authenticity of the banknotes P could not be accurately determined.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to prevent the effects of dust, chips, etc., reduce the effects of deterioration of the standard plate itself, and improve accuracy. An object of the present invention is to provide a paper sheet discriminating device capable of determining the authenticity of paper sheets.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention is designed to obtain a stable amount of light from the paper sheets by arranging the standard plate at a position away from the transport surface of the paper sheets. It is.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 1 will be described with the same reference numerals. In FIGS. 2 and 3, reference numeral 1 denotes a dark box (sealed box) through which banknotes P are conveyed in the direction of arrow a.

A light source 2 for timing generation and a light receiver (for example, a photodiode) 3 are provided facing each other on the bill entry side of the dark box 1. Also, approximately in the center of the dark box 1, there is a light 8!4 that illuminates the banknotes P being transported, a standard plate 5 to which the light from this light source 4 is irradiated, and a standard plate 5 when the banknotes P are not present. A light shielding plate 8 as a light shielding member that is irradiated with light from the light source 4, a lens 9 and an optical fiber 101 that guide the light from the transported banknotes P and the standard plate 5. The light guided by these is filtered (sensitive to blue wavelengths). A light receiver (for example, a photodiode) 7 is provided which receives light through the light receiving device 6. The light source 4 is configured to detect the fluorescent whitening agent component contained in the banknote P using, for example, a light source for irradiating ultraviolet rays. Further, the standard plate 5 is coated with a fluorescent substance inside, and as shown in FIG.
light source 4).
The light is constantly illuminated. moreover,
The light shielding plate 8 has at least its surface (the surface irradiated with light)
is painted black, and is disposed facing the light source 4 with the banknotes P to be conveyed interposed therebetween.

In such a configuration, when the banknote P is transported, first passes through the timing generation light receiver 3, and reaches the position of the standard plate 5, it is irradiated with ultraviolet light by the light WA4. The light excited by the irradiated ultraviolet light enters the optical fiber 10 via the lens 9.

Further, the till quasi-plate 5 is constantly irradiated with ultraviolet rays by the light source 4, and emits light by being irradiated with the ultraviolet rays, and the light enters the optical fiber 10 via the lens 9. The optical fiber 10 combines the light from the bill P and the light from the standard plate 5 into one, and guides the light to the light receiver 7 via the filter 6. Normally, banknotes P do not contain a fluorescent whitening agent component, but those copied using a copying machine or the like contain a fluorescent brightening agent component. This is because commercially available white paper contains a bleaching agent to whiten the color. When a banknote P containing a fluorescent whitening agent component is irradiated with ultraviolet rays, the banknote/P
emits blue-white light. Filter 6 filters this bluish-white light.
The light is detected by the photoreceiver 7. In the case of genuine and correct banknotes, the excitation light does not enter the light receiver 7 because it does not contain a fluorescent whitening agent component, and only the light from the standard plate 5 is detected.

On the other hand, as mentioned above, the surface of the light shielding plate 8 is painted black, and normally, when there is no bill P, light other than the standard plate 5 enters the light receiver 7, and the bill P has a hole. It is possible to prevent unnecessary light from entering in cases such as cases, and to detect the entire surface of the banknote P including the edges. In addition, since the standard plate 5 is located outside the field of view for detecting the banknotes P, it is difficult for dust and debris to enter, and the light from the standard plate 5 can always be received even while the banknotes P are being transported. The light intensity of the banknote P itself is obtained by subtracting the light intensity when the banknote P is not in the detection field of view from the light intensity when the banknote P is not in the detection field of view, and even if the standard plate 5 deteriorates, it will not be affected by it. The purpose of providing the standard plate 5 is to use it as a reference for diagnosing the light source 4 (whether it is lit or not) and determining the gain of a processing circuit, which will be described later.

FIG. 4 shows an example of a processing circuit. That is,
The timing generation photodetector 3 is connected to an amplifier 11, and the output of the photodetector 3 whose level has been amplified by the amplifier 11 is input to a timing generation circuit 12. This timing generation circuit 12 generates a timing signal T1. which is used in this processing circuit. Generates T2. Further, the light receiver 7 is connected to the amplifier 1.
The output of the photoreceiver 7, which has been level-amplified by the amplifier 13, is connected to the zero clamp circuit 14 and the differential amplifier 15.
are respectively input, and the level when the banknote P is not in the detection field of view is subtracted from the level when the banknote P is in the detection field of view. In other words, [
(Light intensity of banknote P + light intensity of standard plate 5) - (light intensity of standard plate 5) = light intensity of banknote P] is obtained, and the comparator 1
6 and also passes through an integrator 17 to a comparator 18
is input to. This is because when a banknote is copied using paper containing an optical brightener component, the amount of output signal varies depending on the amount of printed pattern, and when the entire banknote has a pattern, it is output at a certain level throughout the banknote, so the raw signal It is impossible to directly cut the level with , and in this case it is easier to calculate the difference by integrating. Also, if there is a white area with no pattern, it will be easier to distinguish if the level is cut directly using the raw signal. For this reason, the comparator 1 that compares the signal integrated by the comparator 17
8 and are compared with the reference levels Lr and L2 from the reference value generation circuit 19 in their respective comparators 16 and 18,
Each comparison result is input to the determination circuit 2o.

The determination circuit 20 determines the authenticity of the banknote P by performing various determination calculations on the outputs of the comparators 16 and 18, and outputs the determination result. That is, the determination circuit 20 determines that the banknote is a counterfeit banknote by, for example, taking the logical sum of each output signal of the comparators 16 and 18, and if a 1°' signal is obtained, it is determined that the banknote is a counterfeit banknote, and if a 110'' signal is obtained, the banknote is a counterfeit banknote. It is determined that the banknote is a banknote.The timing chart of the processing circuit explained above is shown in FIGS. , (c) and (f) show the case of a banknote with a partial abnormality, and the figures (d) and (i) show the case of a banknote with an overall abnormality, respectively.

With the configuration described above, by arranging the standard plate 5 at a position away from the banknote conveyance surface, it is possible to prevent the effects of dust, flakes, etc., and also to prevent the effects of deterioration of the plate itself. The amount of light on the banknotes is reduced, a stable amount of light is obtained, and the authenticity of banknotes can be determined accurately.

In the above embodiment, a case has been described in which a light source for irradiating ultraviolet rays is used as the light vA4 to detect a fluorescent brightener component contained in a banknote, but the light source 4 may be a fluorescent lamp, a tungsten lamp, a halogen lamp, or The detection target may be the color component or the degree of dirt on the banknote. Moreover, the light source 4 is
Although it is located in front of the light receiver 7 with respect to the conveyance direction of the banknote P, it may be located in the reverse direction. Further, although the timing generation light receiver 3 is independently provided with light [2, the light source 4 may be used instead.

In addition, in the above embodiment, the case where the application is applied to the authenticity determination of banknotes has been described, but the present invention is not limited to this, and can be applied to other paper sheets such as checks, securities other than banknotes, or printed matter. It can also be applied to truth/false or pass/fail judgments.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent the influence of dust, clumps, etc., and also reduce the influence of deterioration of the standard plate itself, and to accurately determine the authenticity of paper sheets. It is possible to provide a paper sheet discrimination device that can perform the following operations.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing a conventional paper sheet discrimination device;
2 to 5 show an embodiment of the present invention,
2 is a side view, FIG. 3 is a front view, FIG. 4 is a block diagram of the processing circuit, and FIG. 5 is a timing chart for explaining the operation. P...Banknotes (paper sheets), 1...Dark box (sealed box), 4
...Light source, 5...Standard plate, 7...Receiver, 14.
...Zero clamp circuit, 15...Differential amplifier, 17...
・Integrator, 16.18... Comparator, 1... Reference value generation circuit, 2°... Judgment circuit. Agent Patent Attorney Noriyuki Chika (1 person) Figure 1 Figure 3 Figure 7

Claims (3)

[Claims] (1) A light source that irradiates light onto paper sheets being conveyed, a standard plate that is irradiated with light from this light source and placed at a position away from the conveyance surface of paper sheets, and a light source that irradiates light from the light source. A light receiver receives light from the paper sheets and standard plate and converts it into an electrical signal, and the output and power of this light receiver determines how much light is emitted from the paper sheet based on the amount of light from the standard plate. 1. A paper sheet discriminating device comprising: a determining means for determining the authenticity of a paper sheet by determining whether or not the paper sheet is authentic or not. (2) The paper sheet discrimination device according to claim 1, wherein the standard plate is constantly irradiated with light from a light source. (3) The paper sheet discriminating device according to claim 1, wherein the light source and the standard plate are arranged in a sealed box and isolated from the paper sheet transport path.