JPH021649Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention uses an ultraviolet lamp to detect the optical brightener component contained in paper sheets to determine the quality of paper sheets. The present invention relates to a paper sheet discriminating device.

(Prior Art) Conventionally, in a paper sheet discriminating device, when determining whether a paper sheet is good or bad, a method has been adopted in which the shape, printing color, printing pattern, etc. of the paper sheet are noted and recognized. However, in recent years, with the development of printing technology, especially the development of copying machines, it has become easy for anyone to make copies, and it has become impossible to judge the quality of a product by simply recognizing the print color or print pattern. Furthermore, there has been a desire for an apparatus that can determine the quality of paper sheets using a cheaper and simpler method.

Therefore, devices have been devised to detect fluorescent brightener components contained in paper sheets, and there is a device as shown in Japanese Patent Application Laid-Open No. 119789/1989.

This device irradiates ultraviolet rays, detects the reflected light, and determines whether a predetermined level has been reached, thereby detecting whether a paper sheet contains a fluorescent whitening agent.

(Problem to be Solved by the Invention) However, conventional devices can detect paper sheets that contain a fluorescent whitening agent and that have no printed pattern in a predetermined area. However, if the printed pattern covers the entire surface, the amount of reflected ultraviolet light decreases, making it impossible to detect even if the paper sheet contains a fluorescent whitening agent.

Therefore, in the conventional apparatus, there was a problem in that it was not possible to reliably detect whether a paper sheet contained a fluorescent whitening agent.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a paper sheet discrimination device that can detect whether a paper sheet contains a fluorescent whitening agent, regardless of the presence or absence of a pattern on the paper sheet. .

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention irradiates paper sheets with light, receives the reflected light from the paper sheets with a light receiver, and generates a photoelectric generator. In a device that performs conversion and determines the quality of paper sheets based on output signals from a light receiver, an ultraviolet lamp serves as a light source of irradiation light, a light receiver detects a fluorescent whitening agent component contained in paper sheets, a first comparison means for determining whether the output of the light receiver is below a predetermined level; and a first comparison means for integrating the output of the light receiver and determining whether the integrated value is below a predetermined level. 2 comparison means, and means for determining the quality of paper sheets based on the comparison results of the first and second comparison means.

(Function) The first comparison means compares the receiver output with a predetermined level, so it can detect a partially patternless white area, and the second comparison means compares the integrated value of the receiver output with a predetermined level. Therefore, it is possible to determine the presence or absence of a fluorescent brightener component even in paper sheets that have patterns throughout.

(Example) Hereinafter, the present invention will be explained with reference to an illustrated example.

FIG. 1 is an explanatory diagram showing the schematic configuration of the device of the present invention. In the figure, 1 indicates the outer box of the device, and inside it there is a timing light source 2, a timing receiver 3, a light source for ultraviolet irradiation ( (hereinafter referred to as UVLamp)
4, a light receiver 5, a standard plate 6, and a filter 7 are arranged. The paper sheet is conveyed in the conveying direction of arrow A, first passing through a timing light receiver 3, and when it reaches the position of the standard plate 6, it is irradiated with ultraviolet light by a light source 4 consisting of an ultraviolet lamp. The light excited by the irradiated ultraviolet rays enters the light receiver 5 via the filter 7. Normally, commercially available paper itself contains a bleaching agent to whiten its color, and paper sheets for securities, such as banknotes, do not contain optical brighteners (hereinafter referred to as bleaching ingredients). Copies made using a copying machine contain bleaching ingredients, and when ultraviolet rays are irradiated onto paper sheets containing bleaching ingredients, the sheets emit a bluish-white glow. This blue-white emitted light is detected by a light receiver 5 via a filter 7 (sensitive to blue wavelengths). In the case of genuine banknotes, since they do not contain bleach components, the receiver 5
No excitation light is incident on the .

FIG. 2 is an example of a processing circuit of the embodiment shown in FIG.
FIG. 3 is a timing chart of the processing circuit example in FIG. 2.

The timing photodetector 3 is connected to an amplifier circuit 8', the level is amplified, and the output is sent to the timing circuit 1.
It is input to 0. The timing circuit 10 generates various timings used in the processing circuit and also generates control timing signals to the gain control circuit (hereinafter referred to as AGC circuit) 9. This AGC
The circuit 9 corrects output changes due to a decrease in the light intensity of the light source while the paper sheet does not reach the viewing surface.
The output of the light receiver 5 is stabilized and kept at a constant level.

The output of the amplifier circuit 8 is input to a gate circuit 11, where only the range necessary for discrimination is taken out, and is connected to a first comparison circuit 13, which serves as a first comparison means for directly comparing the amplified signals, and is connected to an integration circuit 12. is also connected. The output of the integrating circuit 12 is input to a second comparing circuit 13' serving as a second comparing means, and the integrated output is compared with a predetermined level.

In other words, when a banknote is copied using paper containing a bleach component, the amount of output signal varies depending on the amount of printed pattern, so if there is a pattern on the entire paper sheet, the signal is output at a low level over the entire paper sheet, and the signal is output at a low level. If the signal is directly level-cut, it cannot be detected, so by integrating it, the difference from normal banknotes can be obtained. Furthermore, if there is a partially white area without a pattern, this can be determined by directly cutting the level of the raw signal from the amplifier circuit 8. For this reason, a first comparator circuit 13 for directly comparing the raw signals and a second comparator circuit 13' for comparing the output integrated by the integrating circuit 12 are provided, and the output of each comparator circuit is determined. It is input to the determination circuit 15 as a means, and internally
The OR condition is taken and the final output is produced. In addition, in the above embodiment, the light source 4 is located along the light receiver 5 with respect to the conveyance direction.
Although it is located closer to you, it may be located further back.

Furthermore, although the timing light receiver 3 has an independent light source 2, the light source 4 may also be used.

[Effects of the invention] As explained above, according to the invention, by reliably detecting the fluorescent brightening agent component contained in paper sheets, it is possible to determine whether the paper sheets are normal or abnormal. It is possible to reliably determine the quality of the product.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of an apparatus for detecting bleach components showing an embodiment of the present invention, Fig. 2 is a processing circuit diagram of the embodiment of Fig. 1, and Fig. 3 is a timing chart of the processing circuit of Fig. 2. It is a diagram. 2...Light source for timing, 3...Receiver for timing, 4...Light source (UVLamp), 5...Receiver, 6...Standard plate, 12...Integrator circuit, 13'...
...Comparison circuit, 14...Reference value generation circuit, 15...
Judgment circuit.

Claims (1)

[Scope of utility model registration request] A device that irradiates paper sheets with light, receives the reflected light from the paper sheets with a light receiver, performs photoelectric conversion, and determines the quality of the paper sheets based on the output signal from the light receiver. an ultraviolet lamp serving as a light source, a light receiver for detecting a fluorescent whitening agent component contained in paper sheets, and a first comparison means for determining whether the output of the light receiver is below a predetermined level; a second comparing means for integrating the output of the light receiver and determining whether the integrated value is below a predetermined level;
and means for determining the quality of paper sheets based on the comparison result of the second comparison means.