JPS5874439A - Foreign matter detector at inlet of paper sheet handling device - Google Patents

Abstract

PURPOSE:To improve detecting accuracy of foreign matter and versatility, by arranging a detecting coil with a paired oscillating circuit to a throw-in hollowed place of a deposit paying machine and the like and constituting the coil in such a manner that change of an oscillation condition in the oscillating circuit is taken off from a pair of two equal detecting coils in a mutual induction relation. CONSTITUTION:A sheet of paper, if thrown into a throw-in hollowed place, is moved passing between detecting coils 4a, 4b, arranged at a face-to-face position in the hollowed place. At this time, if a metal is cast together with the sheet of paper, eddy current loss is generated in the metal, and loss of the coils 4a, 4b is increased. In accordance with the above loss, oscillation amplitude in an oscillator circuit 21 is decreased, and an electric current of the coils 4a, 4b is also decreased. Accordingly, voltage across output terminals 25 of coils 5a, 5b, in a mutual induction relation with the coils 4a, 4b, is also decreased. Existence of metal in the sheet of paper causes a change of the magnetic flux direction, and a coupling coefficient of the coil is decreased, then voltage of the coils 5a, 5b are further decreased. Accordingly, even a small metal can be high accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foreign object detection device for a paper input slot in a sheet handling device, for example, a foreign object detection device for a banknote input slot in a deposit dispensing machine.

2. Description of the Related Art In some cases, a foreign object such as a clip for bundling paper sheets, or a coin in a banknote handling device, may be accidentally inserted into a paper input port in a paper sheet handling device along with paper sheets. In this case, when the input paper sheet is taken into the apparatus, there is a risk that these foreign objects may become clogged or the conveyance mechanism or other parts may be damaged. Therefore, a foreign object detection circuit has conventionally been provided in the paper sheet input port. Since the foreign objects that cause trouble are mainly metal, a detection coil is used in the foreign object detection circuit. ing. The magnetic flux generated by this sensing coil is directed in the direction in which the paper sheet is introduced. Therefore, if a metal shutter is attached to the inlet, the difference between when the shutter is open and when it is closed (
1 magnetic flux may change, causing malfunction. Also,
The magnetic flux distribution is not uniform within the recess of the input port, and the magnetic flux density is significantly different between the center and the sides, so the detection signal component is small in the center, where the magnetic flux density is low, and the SZN ratio is large, making it possible to Foreign object detection was not expected.

It consists of a detection circuit such as an oscillation circuit that detects changes in the inductance of the detection coil, for example, the detection coil is one of the components, and further processes the output signal of the foreign object detection circuit and outputs a foreign object detection signal. A signal processing circuit was added. In addition, in terms of noise countermeasures, it is undesirable to connect the foreign object detection circuit and the signal processing circuit with a long signal line, and it is difficult to separate these circuits, so not only the detection coil but also the signal processing circuit are connected to the paper input slot. Since it has no choice but to be provided in Furthermore, since the detection circuit extracts only the change in the impedance of the detection coil, it was difficult to detect small metals, and a stable foreign object detection signal could not be obtained.

This invention can always accurately and reliably detect foreign objects, even small metal objects, regardless of the presence or absence of a shutter or the position of the foreign object, can reduce the installation space, and is free from mounting restrictions. The object of the present invention is to provide a device for detecting foreign objects in the input port of a versatile sheet handling device.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In Figures 1 to 3, the paper sheet IPI is fed into the paper sheet input port (1) in which the paper sheet handling device is installed, from this input port (1) toward the inside of the paper sheet handling device. There is a recess f2) for storing and transporting. A shutter (3) is provided at the input (1) so that it can be opened and closed, and a paper sheet entry detector +61 and two pairs of foreign object detection coils (4a) are installed at the recess (2).
(4B), (5A) (5B).

and a sheet passage detector (7) are provided in this order toward the back. At the back of the recess f2+ is the inserted paper sheet I.
A feeding device (8) is arranged for taking PI into the device. Both detectors +61 and +71 are, in this example,
It consists of a photoelectric detector placed so that the projected light traverses the recess (2).

Further, in the recess (2), a stack lift 0 is arranged for carrying the paper sheets (Pl) input into the input a tit to the feeding device (8).This stack lift (101 is , a recess (21), and a conveyor belt (
The IJl and the bell l-031 consist of a paper box (1) fixed to one side thereof.

One or more of the pulleys (141) are driven by a drive device (path shown) to
) moves up and down in the recess (2). The box fil) consists of a bottom plate attached to the belt (131), a side plate that covers three sides except for the belt +131 side, and a movable holding plate () attached to the side of the belt +131 side. The holding plate (12) is configured so that its opposing sides are biased by a spring or other elastic member or a suppressing member (not shown).Normally, the box (11) is provided with a recess (2
) is located at the top of the box and has a presser plate (121 is a bell) +1
It is located close to 31. When it is necessary to insert paper sheets, the shutter (3) is first opened.

When a sheet of paper is thrown into the box (11), this is detected by a feeding detector (not shown), and the presser plate Q2+
moves and presses the paper inside the box (11). In this state, the box (11) containing the paper (P) is descending inside the recess (2), and the paper (Pi is the feeding device (
8). During the conveyance process of this paper sheet (Pl), the entry and passage of the sheet (Pl) is detected by detectors +61 and +71, and the presence or absence of foreign objects, especially metal, is detected by detection coils (4A) to (5B).Stack lift (10
) is likely to be made of non-magnetic material.

The feeding device (8) includes a feeding roller (15) that is rotationally driven.
) and a friction roller (1G) in contact with this. - Holder plate of the box (11) (There is a paper feed opening in the lower part of the side facing the box, and if no foreign matter is detected, the paper will pass through this feed opening and move to both rollers 5). (They are fed out one by one by 1θ. If a foreign object is detected, the paper sheet tP) is immediately raised together with the box (11), the shutter (3) is opened, and the paper sheet (Pl is returned). Ru.

The detection coils (4'1) (sA) and (4B) (5B) are
2 to form a recess (2) so as to sandwich the recess and face each other;
located on one side wall. And each coil (4A)
~(5B) are wound in a plane parallel to these side walls. Therefore, the magnetic flux generated from the detection coils (4A) to (5B) is directed in a direction across the recesses [2, 1 and the sheet tPl inserted into the recess (2). Detection coils (4A) (4B) are respectively detection coils (5A)
It is wound on top of (5B). therefore,
Detection coils (4A) and (5A), and (4B) and (5B) are coupled by mutual induction. In Figure 3,
The detection coils (4A) (5A) are each wound in one layer, but may be wound in two or more layers. Also,
A coil (5A) can also be wound on top of the coil (4A). These are the detection coils (4B) (5B)
The same applies to

FIG. 4 shows an example of a foreign object detection circuit.

This detection circuit (indicated by (to) in FIG. 5) is composed of a Hartley oscillation circuit (21) and an output circuit for its oscillation signal. The oscillation circuit (21) includes a transistor (2
) and a resonant circuit, and this resonant circuit connects the detection coil (4'
A) (4B) and a capacitor 031. Detection coils (4A) and (4B) are connected in series. The output circuit consists of sensing coils (5A) (5B) coupled to coils (4A) (4B), and the coils (5A) and (5B) are connected in series.

Oscillation circuit Q old 1 oscillates at a constant frequency and constant vibration rlj. When the metal is thrown into the recess (21) together with the paper sheet tPl, eddy current loss occurs in this metal.

Since the loss of the detection coils (4A) (4B) increases, the oscillation width of the oscillation circuit (21) decreases. Due to this decrease in the amplitude, the current flowing through the coils (4A) (4B) 6c also decreases, so the decrease in the oscillation width remains unchanged in the coil (5).
A) This occurs as a decrease in the voltage (or current) between both ends (output terminal f25+) of (5B). Due to the presence of metal in the paper leaf (Pl), the direction of magnetic flux changes and the coil (4A)
Since the magnetic flux linking both (5A) and (4B) and (5B) decreases, the coupling coefficient of these coils becomes smaller, and the voltage of coils (5A) (5B) further decreases. For this reason, even small metals can be reliably detected. Moreover, since the output of the oscillation circuit (21) is taken out through the coupling of the coils (4A) to (5B), the detection circuit (to).

It becomes possible to disconnect the output terminal (c) from the signal processing circuit described later, and only the detection circuit (to) can be mounted near the input port (1). 161. , :, FIG. 5 shows an example of a signal processing circuit that detects the presence or absence of a foreign object from a change in the output of the detection circuit, and FIG. 6 shows its output signal waveform. The signal [C1] applied to the detection coil (5A) C5B) of the detection circuit (to) is detected by the detection circuit (31) and becomes a signal tDl, and then this signal (Dl is applied to the amplification circuit 132).
1 and is inverted and amplified to become a signal (E). This signal FEI
is differentiated by a differentiating circuit (to), and the positive peak of its output IF) is held by a peak hold circuit (to). This peak hold circuit (incorporated) has an integration function, and narrow signals such as noise are not peak held, but only the peak of the signal component due to foreign matter is held. The output of the hold circuit (34) is converted into a digital signal by the AD conversion circuit (to) and encoded to become signal II (1. This signal [Hl is CP
U, +4 (input to 11 input/output interfaces).

Detector 1611? + detection signal tA) (Bl is used as a gate control signal. When the sheet of paper (box 01 containing Pl) falls and is detected by the detector (6), the detection signal tA) rises. At this point, the output [H] of the AD converter (to) is set as the reference value by CPU f4.
Read by 01. Box αD is the detection coil (
4A) to (5B) and is detected by the detector (7), its output IB) rises. box 0
1) further falls and passes the position of the detector (7), the signal IBI falls. At this point, the output of the AD converter (to) (Hl is read as the measured value by CPU (4 (ll), the output tB of the detector (7)) is also input to the delay circuit plane, and the signal [ A reset signal is output from one circuit side after a fixed time delay from the falling edge of signal B), and the peak hold circuit is reset.

A tolerance range for the difference between the reference value and the measured value is determined and stored in advance in the c p U 140), and when the difference between the reference value and the measured value exceeds this tolerance range, a foreign object detection signal is output. be done. This detection signal is sent by the sending control circuit 091 to a display device such as a CR'T installed in the sheet handling device, and a message indicating that a foreign object has been detected is displayed.

The oscillation state (oscillation [IJ) of the detection circuit (to) changes somewhat depending on ambient conditions such as humidity. However, in the circuit shown in Fig. 5, the oscillation width of the detection circuit (■) when paper sheets (Pl) are started to be carried in by the stack lift OQ is used as the reference. Accurate foreign object detection is possible.

Figure 7 shows the position of the recess (2) in the input port (1) from one detection coil (4A) to the other detection coil (4B) (
The change in the oscillation width of the detection circuit (see Figure 2)
ΔW) is shown. This change (ΔW)
is the difference in the oscillation width between the case where there is no foreign object in the recess (2) and the case where there is. The graph shown by the solid line is based on the detection coils (4A) (4B) in this invention, and the graph shown by the broken line shows the change in the conventional example in which the detection coil is wound in a ring around the recess (21). As is clear from this graph, in the conventional device, the variation (ΔW) at the center of the recess (21) is significantly reduced, but with the arrangement of the detection coils (4A) (4B) of this invention, Since the magnetic flux density is almost uniform regardless of the position, the amount of change (ΔW) is almost constant.

In the above embodiment, the detection coils (4A) (4B) are connected to the resonant circuit of the Hartley oscillation circuit, but they can also be connected to other oscillation circuits.

As described above in detail, according to the present invention, the pair of first sensing coils are disposed to face each other with the recess in between so that the generated magnetic flux crosses the recess. Therefore, since the density of the magnetic flux generated from the first detection coil is almost uniform in the lateral direction of the recess, foreign objects can be detected regardless of the position where the sheet enters, and the magnetic flux is perpendicular to the direction in which the sheet is inserted. Therefore, the amount of change in the inductance of the first detection coil due to the foreign object becomes large, the SZN ratio can be reduced, and highly accurate foreign object detection becomes possible. The magnetic flux crosses the recess, and the influence of the magnetic field does not extend to the vicinity of the shutter of the input port, so even if a metal shutter is installed, there is a risk of false detection caused by this shutter. That's not it.

Further, a pair of second sensing coils are provided, each of which is coupled to the first sensing coil by mutual induction, and a change in the oscillation state of an oscillation circuit that detects a change in inductance of the first sensing coil is detected by a second sensing coil. Since it is taken out from the sensing coil, it becomes possible to disconnect the subsequent signal processing circuit connected to the second sensing coil and place it at another location.

Therefore, only the two detection coils and the oscillation circuit can be placed near the sheet input port, and the signal processing circuit can be incorporated into the main control unit of the sheet handling device, which eliminates mounting constraints and makes it possible to Sex increases. This is because the mutually induced magnetic flux between both detection coils changes due to the foreign matter thrown in with the paper sheet.

The change in the second sensing coil becomes even larger,
Even small foreign objects can be detected reliably. Furthermore, since it is sufficient to arrange two pairs of detection coils on both sides of the recess, the configuration is simple and requires only a small space.

[Brief explanation of the drawing]

, Fig. 1 is a schematic cross-sectional view showing the structure of the paper input port, Fig. 2 is a perspective view showing the arrangement of the detection coil, Fig. 3 is a cross-sectional view taken along the line ■-■ in Fig. 2, and Fig. 4 is a circuit diagram showing one example of a detection circuit, FIG. 5 is a block diagram showing a processing circuit, and FIG. 6 is a time chart 1 showing each signal in the processing circuit.
FIG. 7 is a graph showing the characteristics of the foreign object detection device. (1)...Inlet, (2)...Recess, (4~(4B)
) (Go to 5 (5B)...Detection coil, (21+...
Oscillation circuit, circle...detection circuit. 4 people other than the above

Claims (1)

[Claims] (1) A pair of first detection coils and a pair of second detection coils provided in the recess of the input port, and an oscillation circuit having the first detection coil as a component, and a pair of second detection coils. The first sensing coil is placed facing each other across the recess so that the generated magnetic flux crosses the recess, and the first sensing coil and the second sensing coil are coupled by mutual induction, and oscillation occurs. An input port foreign object detection device in a sheet handling device, in which a change in the oscillation state of a circuit is detected from a second detection coil. +21 Equipped with a paper sheet entry detector placed closer to the entrance than the detection coil in the recess of the input port, and a circuit that detects a reference value regarding the oscillation state of the oscillation circuit at the time when the entry detection signal is output, and this reference Claim fJS11 in which a change in the oscillation state of the oscillation circuit with respect to the value is detected.
An inlet foreign object detection device in the paper sheet handling device according to item 1.