JPS5897603A - Thickness detector for paper sheet or the like - Google Patents

Abstract

PURPOSE:To prevent an error caused by variation in the mechanical and electrical characteristics of a thickness detection part by providing a detecting means for paper sheet in front of the thickness detection part, giving a sweep and detecting a reference level right before paper sheet reaches the thickness detection part, and subtracting the reference level from an output obtained thereafter. CONSTITUTION:Two narrow driven rollers 2 which are displaced independently in accordance with the thickness of paper are provided successively in the axial direction of a driving roller 1 for conveying the paper sheet. A manget 5 over the driven rollers 2 and a magnetism-sensitive element 7 on a supporting frame 6 constitute a thickness detecting means. The detecting means consisting of projectors 10a and 10b is provided in front of the detection part. The output of each thickness detecting means is swept by a multiplexer by the output of said detecting means right before paper sheet comes to between the rollers 1 and 2 to detect a reference level, which is subtracted from the output of the thickness detecting means by the 2nd or succeeding sweep.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to improve the thickness of paper sheets, cellophane tape attached to paper sheets,
Alternatively, the present invention relates to an improvement of a thickness detection device used for detecting double-bill type banknotes, double-feeding banknotes, denatured banknotes, etc., and detecting repaired banknotes.

Conventionally, this type of thickness detection device required extremely high accuracy in order to reliably detect cellophane tape with a thickness of about 50 microns, and it was necessary to detect discrepancies in the parallelism of the roller axes, degree of wear of the bearings, or the magnet used as the detection means. Since detection accuracy is affected by the temperature conditions of the magnetically sensitive element and changes in characteristics over time, it has the drawback of requiring complicated adjustments before operation. Further, immediately after a thick paper sheet passes through the detection section, a residual level due to a transient response waveform is superimposed on the next detection output, which has the disadvantage of reducing detection accuracy. The present invention aims to solve the above-mentioned problems, and provides a thickness detection device that can obtain an accurate thickness variation value of the palm by detecting a reference level just before reading the detected object. This is what we provide.

This will be explained in detail below with reference to embodiment figures. Figure 1 shows the structure of the device of the present invention, which includes a drive row for conveying paper sheets A at high speed,
A plurality of narrow driven rollers 2 are arranged in parallel in the axial direction of the banknote 71, and each driven roller 22 is adapted to be displaced independently of each other according to the thickness of the banknote. The driven roller 2 is rotatably supported by a rotating frame 4 supported by a shaft 3, and a magnet 5 is fixed to the upper end of the rotating frame 4. This magnet 5 forms a detection means together with a magnetically sensitive element (for example, a Hall element) 7 fixed to the upper part of the support frame 6, and the banknote A
When the bill passes between the drive roller 1 and the driven roller 2, the driven roller 2 is pushed up by the banknote A, the rotating frame 4 rotates, and the Hall element 7 moves according to the distance between the magnet 5 and the Hall element 7. It converts the changing magnetic flux density into an electrical signal. Further, the driven roller 2 is given an appropriate elastic force toward the driving roller 1 by a spring 8.9.

A light emitter 1 is installed in front of the thickness detection section configured as described above.
An optical sensor 10 consisting of an optical sensor 0a and a light receiver 10b is provided, and a rotary encoder 11 is connected to the drive roller 1.

FIG. 2 shows the electric circuit used in the device of the present invention. In FIG. A kakunta circuit CT and a resistor RG are applied to the multiplexer MPX via the amplifier A I * A2 +...An and the capacitor CI + 02...Cn, respectively, and are synchronized with the rotation of the drive roller 1 by the row encoder 11. By sweeping the multiplexer at , the detection outputs are sequentially taken into the A/D converter AD through the amplifier AM. That is, the rotary encoder 1 multiplexer MPX constitutes the sweeping means. Further, the output of the optical sensor 1O is sent to the kakunta circuit C. via the delay circuit DL. The circuit is connected to the reset terminal of CT, and after a certain period of time after the banknote A is detected by the optical sensor 10, the circuit is connected to the reset terminal of CT.
starts counting the output of the low-resolution encoder, and a delay time is set so that the first sweep is performed before the banknote A reaches the thickness detection section. The output of the delay circuit DL and the output of the kakunta circuit CT are also read into the memory ME via the input/output port E0 and processed by the microprocessor CPH together with the output of the A/D converter AD.

Data processing by the microprocessor CPH is performed as follows. As mentioned above, before the banknote A enters between the rollers 1 and 2, the first sweep of the multiplier MPX is performed, and the output of each amplifier A1 to An at this time is A.
/D converted and stored in the memo IJMFi, respectively, and this becomes the reference level for thickness detection. The corresponding reference levels stored in the memory ME are subtracted from the outputs of the amplifiers A1 to An taken in the second and subsequent sweeps. This subtraction result is the detected thickness, and by comparing the value obtained by subtracting the preset value of the thickness of the banknote with an appropriate judgment standard, the abnormality in thickness can be detected. For example, it is detected that there is a place that has been repaired with Sellotape.

Next, Fig. 3 shows a detailed explanation of the present invention, in which Fig. 3a shows the thickness detection points on the banknote A, and Fig. 3 shows the outputs of points A, 4, and No. in Fig. 2. It shows the waveform. First, when the optical sensor output detects the banknote A and starts up, the delay output port of DL becomes "H" level after a delay of t1, and the counter CT starts counting. The first sweep is performed just before the banknote A reaches the thickness detection section, as shown in FIG.
It is performed while the person is being held between the legs. In FIG. 8, waveform C is an arbitrary waveform in the amplifier Al-An.

The output B sampled during the -th sweep is the reference level described above. Amplifier A1%AH
The output is then sampled every second, third, ... mth sweep, and subjected to the data processing described above in the CPU. Here, the reference level sampled in the first sweep described above for each banknote is due to fluctuations in the output of the magnetic sensing element due to temperature changes, fluctuations in the gain of the amplifier Al-An, etc., and the magnet 5 due to wear of the rollers 1 and 2. Depending on changes in the distance between the magnetically sensitive element and the transient characteristics of the entire circuit from the magnetically sensitive element to the coupling capacitors 01 to Cn when banknotes are fed one after another, the outputs of the amplifiers A1 to An etc. may also change from the original standard. It is constantly fluctuating because the next banknote comes in before it reaches the level. Note that when the optical sensor 10 no longer detects the banknote A and the waveform a falls, the delay output j becomes "L" after a delay of t2 time.
” level and the sweep operation stops.

The present invention is constructed as described above, and includes a detection means, that is, an optical sensor, for detecting the passage of paper sheets in front of the thickness detection section, and the output of this detection means activates the sweeping means. The reference level is detected by performing the first sweep just before the leaf reaches the thickness detection section, and the thickness of the paper sheet is calculated by subtracting the reference level from the second and subsequent thickness detection outputs. As a result, it is possible to prevent detection errors caused by changes in the mechanical or electrical characteristics of the thickness detection unit as in conventional methods, and it is possible to perform highly reliable thickness detection without the need for complicated adjustments. There is an advantage.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the device of the present invention, in which a is a front view, b is a side sectional view, Fig. 2 is an electric circuit diagram of the same, and Figs. 8 a and b are explanations of the operation of the same. It is a diagram. DESCRIPTION OF SYMBOLS 1...1 moving roller, 2...Followed roller, 3...Axis, 4...Rotating frame, 5--Magnet, 6...Supporting frame, 7-
...Magnetoelectric conversion element, 8.9...Spring, 10...
・Optical sensor, 11...Lawkliencog, CT・
... Kakunta circuit, RG... register circuit, MPX-
・Multiplexer, DL...Delay circuit.

Claims (1)

[Claims] A drive roller that conveys paper sheets, a plurality of narrow driven rollers that are arranged in parallel along the axial direction of the drive roller and are displaced independently according to the thickness of the paper sheets, and a displacement of each driven roller. A thickness detecting section consisting of a detecting means for detecting and converting it into an electric signal and a sweeping means for sequentially taking out the output of each detecting means is provided in the conveyance path, and a thickness detecting section is provided in the conveyance path to prevent paper sheets from passing before the thickness detecting section. A detection means for detecting is provided, and the sweep means is actuated by the output of the detection means to perform a first sweep before the paper sheet reaches the thickness detection section, and the output of the detection means at this time is used thereafter. A thickness detection device for paper sheets, characterized in that a reference level is used when detecting the thickness of paper sheets.