JPS60171954A - Multifeed detecting device - Google Patents

Abstract

PURPOSE:To automatically make a reference signal by comparing a voltage value of the quantity of light received by the first sheet with a reference voltage value and regarding the reference voltage value to which a compensating current depending upon the count value of pulses according to a comparison output is added as the initial reference voltage value. CONSTITUTION:When the first sheet 1 gets on a photo detecting portion 3, a signal changed in photo detecting level is input to an amplifier circuit 11, and an output signal E0 is input to a level change detection circuit 15. The signal E0 and a reference signal E1 from a reference circuit 5 are input to a comparator 12. When a difference signal is output from the comparator 12, and a compensation designation signal from FF circuit 19 and a paper detection signal from a delay circuit 16 are input, an output signal (b) is output from AND circuit 13 to set the FF circuit 14. When an output signal of the circuit 14 and a pulse signal (a) from a pulse generation circuit 9 are output, a counter circuit 8 counts the pulse number of input pulse signals, and a counter output is input to compensation current feed circuit group 7. The circuit group is turned on to add a compensating current to the initial current. When the reference value increases to reach a paper thickness signal E0, the second and following paper thickness is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a multi-sheet feed detection device for a Kasumi military machine, a printing press, etc., and in particular to an optical detection device that detects a single feed based on a difference in the amount of transmitted light. This is related to improvements.

(Prior art) For example, when printing is performed on a printing machine, the paper to be printed is fed one by one into the printing process, but if two or more sheets are accidentally fed (this is (called sheet feeding)
Sometimes printing errors can occur.

Therefore, in order to prevent this, it has conventionally been done to detect the feeding of multiple sheets at the stage when the sheets are fed into the printing process.

Among these, the following two points are cited as drawbacks of the optical detection device.

(1) When comparing the paper thickness signals of the paper being fed for the first time, it is safe to manually place the paper on the photodetector in order to create a Higeyo Tsukuda before the paper is fed, and completely automatic detection is possible. Can not.

(2) When printed paper is fed, it is impossible to distinguish between the margin area and the printed area, so there is a high possibility of false detection, and printed paper cannot be detected.

In particular, a major drawback is that it is not possible to automatically create a reference signal for comparing the thickness of the second and subsequent sheets of paper for the first sheet of paper fed.

(Purpose) The present invention has been made in view of the drawbacks of the conventional example, and it automatically adjusts a reference signal for detecting multiple sheet feeding and converts the reference signal into a signal of the thickness of the paper fed first. The object of this invention is to accurately detect the feeding of multiple sheets by maintaining the matched reference signal.

(composition) The configuration of the present invention will be explained below based on the illustrated embodiments. ′ The circuit configuration will be explained based on FIG.

A drive current flows through the light emitting section 2 from a light emitting section current sending circuit 4.

Before the paper is fed, the source directly enters the fluorescent section 3 from the light emitting section 2, so a signal of a higher level than the fluorescent section 3 is output. When paper feeding is started and the paper 1 comes onto the light receiving section 3, the light receiving section 3 receives the transmitted light from the paper 1, so that the light receiving level thereof suddenly decreases. This reduced received light level is amplified by the optical amplifier circuit 11, and its output signal is output by the comparison circuit 12 of the difference detection means A. Level change detection circuit 15 of paper detection means B and comparison circuit 170 of comparison judgment means C
This becomes the input signal.

Another input of the comparison circuit 12 is a lower limit value ratio and an upper limit value E, which are used to compare whether the light receiving level of the light receiving unit 3 or the rough light receiving level is the multi-sheet level, and the upper limit value E is set to the judgment level of the thickness of the initially fed paper. Therefore, a reference signal E is inputted from the reference value circuit 5.

Therefore, while there is a difference between the inputs of the comparator circuit 12, a signal is output from this circuit and becomes one input of the AND circuit 13. Furthermore, when there is no difference between the inputs, the zero detection signal from the comparator circuit 12 becomes a reset signal for the flip-flop circuits (hereinafter referred to as F-F circuits) 14 and 19.

fi” -F circuit 1 to the other input of AND circuit 13
When a correction instruction signal is input from 9 and a paper detection signal from delay circuit 16 of detection means B is input, AND circuit 13 outputs a signal S. F due to this signal
- Set the F circuit 14. The output signal of this FF circuit 14 becomes one input of an AND circuit io which is a pulse sending means.

Another input of the AND circuit 10 is a pulse generation circuit 9.
A pulse signal is input. Therefore, while the signal is being output from the F.F circuit 14, the pulse signal a is output from the AND circuit 10 and is input to the clock terminal of the counting circuit 1 of the counting means E. The counting circuit 8 counts the number of pulses input to the clock terminal and outputs the counted number digitally.

What is this output? The compensating current Ic is inputted to the persimmon compensation current sending circuit pestle 7- of the 141 providing means IT, and the compensation current Ic flows from the current sending circuit corresponding to the digital output. This current is the initial current I
o and is supplied to the reference value circuit 5, the reference value E1 is raised by this compensation current, and the initial paper thickness signal Eo
The time when K is reached is the upper limit value of the tsukudai current.

Also, at this time, the circuit 12 outputs the signal power of the detection signal, and F
-F circuit 14 is reset and counting circuit 8 stops counting. By stopping this count at 1, the upper limit value of the compensation current is maintained until the next compensation instruction signal is issued. The above-mentioned initial current sending circuit 6 is for shortening the compensation time m], and is not necessary when there is sufficient margin in the sleeve time.

Next, in the paper detection means B, the output signal E from the amplifier circuits 11 before and after the level change detection circuit 15 detects the paper margin.
A change in o is detected and the detection signal is input to the delay circuit 16. The delay circuit 16 is for providing the detection signal from the level adjustment detection circuit 15 to other circuits after the output signal from the amplifier circuit l11/111 becomes stable.

Next, at the input of the comparison circuit 170 of the ratio soft decision means C.

Output signal E of the amplifier circuit 11. , and a lower limit voltage E2 and an upper limit paper pressure E3 used for determination from the reference value circuit 5. At this time, E and E are compensated with judgment values corresponding to the thickness of the initially fed paper. E from this comparison circuit 17. <'kar2 or E□> E30 signal is output. Fio<j&2 means that the paper thickness detected at this time is thicker than the paper thickness when the compensation was first performed. Also EO1〉
E3 is determined when the paper thickness detected at this time is thinner than the paper thickness when compensation was first applied.

The output from this comparison circuit 17 serves as one input to an AND circuit 18. In addition, when an output signal from the inverter circuit board and a paper detection signal from the delay circuit 16 are input, an output signal C is sent to the output as a multi-sheet feed detection signal.

The output signal of the inverter circuit described above is used to prevent the output signal of the comparator circuit 17 from being sent to the output vane during the first paper in which reference value compensation is carried out.

Next, to explain operation 9 in more detail, first, a paper feed start signal is input to input n. This signal sets the F--F circuit 19 and outputs the arm number. This output signal serves as one input to the AND circuit 130. Further, the signal detected by the rising edge t of this signal is outputted from the rising edge detection circuit 21 and inputted to the recent terminal of the counting circuit 8, thereby setting the counting circuit 8e in the initial state.

Next, when paper feeding starts and the first paper l comes onto the light receiving section 3, the light receiving level of the light receiving section 3 changes. This signal is input to the amplifier circuit 11, and the output signal Eo of this amplifier circuit 11 is input to the level change detection circuit 15. Output signal kJo
After becoming stable, the delay circuit 16 outputs the paper yoshihakugo, which becomes one input of the AND circuits 13 and 18, and the N
1 output signal E of the circuit 11. is input to one input of the soft pJ path 12, and the other input is set to the lower limit value average and upper limit value, which detects the feeding of multiple sheets, and to the judgment level of the initially fed paper thickness. In order to
is entered.

Now, when E+ < Eo, the output from the comparator circuit 12 is 1j, which is connected to one input of the AND circuit 1.3. Another human power input is the sleeve acclimatization signal No. 4M from the Ni゛・k′ circuit 19, and another input to δ and others is: J491.
(AND circuit 1 when woodcutter detection number enters from rjIk lv
Output signal 6 is output from 3, and this signal causes the upper
Set the k circuit 14. This ni′・P′ circuit 14
The output No. 41 becomes one input of the AND circuit lυ, and the pulse signal from the pulse generating circuit 9 also becomes an input 91, and the AND circuit 10 outputs the pulse signal a. This output field pulse signal is input to the clock element of the white circuit 8, and this 61 red circuit 8 receives the input δ pulse 1h.
The number of pulses f2 is counted and the counted number is digitally output. This digital output is input to the inflow/output circuit phase 7, and the current sending circuit corresponding to this digital output is set to 01'J/OF1, and the curve is compensated by the current sending circuit that is turned on. lc (Ic = Mo
X 2°-i 10M, X2'-1-4-ix, x2"
・i ten...±Mn x 2"-i, however, pigeon~M.

corresponds to the digital output of the counting circuit and becomes O or l. (l is the minimum unit of compensation current) flows, this current is added to the initial current 1o, and the current is 1 (1) to the reference value circuit 5.
-Io+lc) flows.

Due to this compensation, the reference value E1 increases and the paper thickness signal E. getting closer to Thereafter, when the paper thickness reaches Eo, the comparison circuit 12 outputs a zero detection signal, which causes the F-F circuit 14 to be reset 11 and the transmission of pulse signals to the counting circuit 8 to be prohibited. Therefore, N1 number circuit 8
stops counting, holds the state of the digital output at this time, and maintains the current corresponding to this digital output until the next paper feed start signal is input. Therefore, when the thickness of the paper fed from the second time onward is the same as the thickness of the paper fed first, the output signal b0 of the amplifier circuit 11 and the reference value conversion signal E of the reference value circuit 50 are output.

is equally compared with the lower limit value E2 and the upper limit value E in the comparison circuit 17, and Ex<bo<Ex and 1. C ratio soft circuit 1
No. 16 cannot be sent out from the output of '/. If the paper is fed a second time, the thickness of the paper may be thicker than the paper that was fed the first time.

Eo<Ex, and the ratio soft circuit 17 outputs 1g. At this time, I think that one piece of paper is a large number of sheets. Also, when the second time and after the death, it was difficult to pay attention to Kf.
As for iio, b6>M, and a signal is output from the ratio soft circuit 17. At this time, it seems that there will be a large number of people who have surpassed NU from the number of m1 sheets of paper. Specific soft times wT17
The output signal becomes one input of the AND circuit 18, and is also input to the inverter l! ! When the output signal from L addition is input to the AND circuit 18, if the human power 6 is received from the cancer extension sweetfish 16, the output signal d from the AND circuit 1δ of the seventh is inputted to the AND circuit 18. ℃ or send a large number of copies and become a grudge.

Figure 2 shows M1 paper 6re1 kosatsu waase (amplifier circuit output signal j!io) with Jun and Shun, 4 Hakugo disease who fathered Sode, and 1ifi yearning for @o. The crow and the upper limit of E island are filled with things that are not included in the enclosure. The same figure (a) is the axial diagram of Sodejima, the same figure (1
)) is an axial diagram of the sleeve body. tl construction E6= in this part
E, and ΔE indicates the increase in the reference value after the sleeve adjustment.

By the way, the current inertia 1c for thin paper requires a longer compensation time than for thick paper. One way to reduce that time is to raise the minimum unit of compensation for 2-ryu at the time of the attack.

As a method, when inputting the pulse number from the pulse generator to the counting means, for example, as shown in Fig. 3, it is divided into thin paper and thick paper and manually inputted to the clock terminal of the counting circuit 4!4.

When the paper is made of cardboard, a pulse signal is sent from the air and l to the i1 ridge circuit. The minimum unit of relaxation when healthy is 2°.
It becomes 1. °'Next, when the paper is thin, a pulse signal is sent from AND2 to the &r'i number circuit. Suppose that the minimum unit of inertia flow in this case is 28·i.

In addition, by using the i1' number circuit 1& which can perform up-counting and down-counting with the function of the reset port 1 in the counting circuit, the initial % flow [If all the g circuits are set to 8, the The increase in the standard value according to g is a] function,
It is also possible to measure the large amount of compensation time.

That is, in this case, the current of the preset value initially flows as the initial current to the reference A direct circuit, and the standardization number obtained at this time is the number of clocks above the paper thickness signal nEo. The compensation voltage ηt? is calculated by counting down from the preset value. Reduce the reference signal distortion to nE6 of the paper thickness signal. On the other hand, the reference material is nB6, which is the paper thickness signal.
When it is below, the count is up-counted and added from the preset value to increase the compensation current and raise the reference No. 18 E to the paper thickness signal n1io.

(Effects) According to the present invention, the reference signal for multi-sheet recognition is automatically generated. J? It is possible to accurately detect the feeding of multiple sheets.

[Brief explanation of drawings]

Figure 1 shows the causes of a multi-sheet feed detection circuit according to an embodiment of the present invention, Figure 2 shows the characteristics of paper thickness No. 48, <a> shows the characteristics before compensation, and (b) shows the characteristics after side scanning. FIG. 3 is a diagram showing another embodiment of the compensating means portion. 5...Reference value circuit, 6...Counting circuit,
12... Comparison circuit of the first body, 17... Comparison circuit of the second body.

Claims (1)

[Claims] i! corresponding to the amount of light received in the margin of the first paper! With the opening price. A comparison circuit is provided to compare the voltage value with an arbitrary reference voltage value of the reference value circuit, and the number of pulses corresponding to the output of this comparison circuit is counted by the # number circuit. By continuing to supply the reference voltage value to the reference value circuit and making this reference voltage value match the initial paper thickness signal to determine the initial reference voltage, the feeding of multiple sheets of paper from the second sheet onward is controlled. A multi-sheet feed detection device characterized in that a second comparison circuit for detection performs detection.