JPS63185754A - Multiple feeding detecting device for printing paper - Google Patents

Abstract

PURPOSE:To securely detect multiple feeding regardless of the types of sheets of printing paper by photoelectrically converting the output of a through-light sensor provided on the passage of a sheet of printing paper and comparing said output with two reference voltages which are arbitrarily set with one voltage high while the other low. CONSTITUTION:The output of a through-light sensor 21 provided on the passage of a sheet of printing paper is photoelectrically converted and inputted into first and second comparators 22, 23. The reference voltage of the comparator 22 is set lower than the output voltage of the sensor 21 through which a sheet of printing paper is not passing while higher than the output voltage of the sensor 21 at the time of one sheet of printing paper by means of a variable resistor 24. Also, the reference voltage of the comparator 23 is set lower than the output voltage of the sensor 21 at the time of one sheet of printing paper while higher than the output voltage of the sensor 21 at the time of two sheets of printing paper by means of a variable resistor 25. And, the outputs of the comparators 22, 23 are inverted and inputted into an FF 26 to detect double feeding, while displaying whether one-sheet feeding or multiple sheet feeding on displays 32, 34. Thereby, it is possible to cope with various sheets of printing paper merely by adjusting the variable resistors 24, 25, enabling the detection of double feeding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for detecting multiple feeds of printing paper when feeding printing paper to a printing machine.

BACKGROUND OF THE INVENTION In various printing fj machines, a sheet-fed press is provided for supplying printing paper. A sheet-fed press feeds a large number of stacked sheets of printing paper to a printing machine one by one.
In order to prevent two or more sheets of paper from being fed to a printing machine in an overlapping manner, various multiple feed detection devices have been proposed in the past.

FIG. 2 is a sectional view showing an example of a conventional multiple feed detection device. Printing paper 1 is placed on belt 2 in the six directions of arrows (the printing machine is placed in front of this direction).
Supplied. A microswitch 4 having a movable roller 3 is arranged above the belt 2 in order to detect that two or more sheets of printing paper 1 are being fed on the belt 2 in an overlapping manner. Here, when the printing paper 1 is sent in a double layered state as shown by the phantom line B in FIG. 2, the movable roller 3 moves in the direction of the arrow C and the microswitch 4 is turned on. By arranging the movable roller 3 in such a manner, multiple feeding of printing paper can be detected.

On the other hand, FIG. 3 shows another example of the conventional printing paper multiple feed detection device. Here, a light source 6 that irradiates light in a direction perpendicular to the main surface of the printing paper 1 that is sent in six directions of arrows,
A light receiving element 7 that receives light emitted from the light source 6 is provided. Here, the transmittance when the irradiated light passes through one sheet of paper.

Multiple feeding of printing paper is detected based on the difference in transmittance when two or more sheets overlap.

[Problem 1 to be Solved by the Invention The multiple feed detection device using the microswitch 4 shown in FIG. 2 has various problems as described below.

In other words, if the printing paper 1 is quite thin, it will not be very thick even when two sheets are overlapped.Therefore, when two sheets of printing paper 1 are sent in an overlapped state, make sure to move the movable roller 3. It is extremely difficult to configure the system to detect multiple feeds.As a result, malfunctions often occur when the printing paper is extremely thin.

Furthermore, the direction of the printing paper 1 may change on the belt 2 due to the front end of the printing paper 1 colliding with the movable roller 3 . As a result, the printing paper 1 could not be fed to the printing machine in the correct orientation.

Furthermore, since the printing press sequentially supplies an extremely large number of meters of printing paper, the contacts of the microswitch 4 are likely to wear out after being used for a certain period of time. Therefore, the microswitch 4 had to be replaced periodically.

On the other hand, in the photoelectric multiple feed detection device shown in Fig. 3,
There are no problems when using the microswitch 4 as described above. However, as shown in FIG. 4, when it is necessary to supply printing paper 10 with a pattern printed on the base in advance in areas 8 and 9, the sensitivity of the light receiving element 7 is adjusted according to the darkest color area. Must. For example, in the printing paper 10 shown in FIG. 4, the density of the pattern area 8 is the highest, and the transmittance of light passing through the pattern area 8 is such that a pattern is formed when two sheets of printing paper 10 are fed in an overlapping manner. If the light transmittance is equal to or lower than the light transmittance in the area 11 where the pattern is It will be determined that multiple sending has occurred.

Therefore, when printing paper 10 on which the pattern area 8°9 is printed as a base as shown in FIG. 4, or when performing multicolor printing,
When printing on both sides of paper, the sensitivity of the light-receiving element 7 must be adjusted each time depending on the printing paper to be supplied. However, in ordinary general-purpose printing machines, it is common for the same machine to print on various types of paper. Therefore, it is extremely troublesome to accurately set the sensitivity of the light receiving element 7 for each printing paper or each time printing is started.

Therefore, an object of the present invention is to provide a multi-feed system that can reliably detect multiple feeds regardless of the presence or absence of base printing or the thickness of the paper, and that can easily adjust W4 even when the printing paper is changed. The object of the present invention is to provide a detection device.

[Means for Solving the Problems] The printing paper multiple feed detection device of the present invention irradiates the printing paper with light and detects changes in its transmittance in the same manner as the conventional multiple feed detection device shown in FIG. It detects multiple feeding based on the following characteristics.

That is, in the area through which the printing paper passes, a light-receiving sensor is arranged that generates a voltage signal of a different magnitude depending on whether one printing paper is passing through or two or more overlapping printing papers are passing through. Further, in order to binarize the output signal of the light receiving sensor, a first F3 and a second reference voltage signal generating means are provided which generate a first or second reference voltage signal, respectively. This first reference voltage signal is lower than the output voltage of the light receiving sensor when no printing paper is passing through it, is relatively higher than the output voltage of the light receiving sensor when there is only one printing paper, and is relatively higher than the output voltage of the light receiving sensor when no printing paper is passing through. The reference voltage signal is set to a value between the value of the output voltage of the light receiving sensor when there is only one sheet of printing paper and the output voltage of the light receiving sensor when two or more sheets are being fed in an overlapped manner.

A first comparing means is connected to the above-mentioned light receiving sensor and the first reference voltage signal generating means. The first comparison means compares the output voltage of the light receiving sensor and the first reference voltage,
One of the binarized output signals is output when the printing paper is passing, and the other output signal is output when the printing paper is not passing.

Further, a second comparing means is connected to the light receiving sensor and the second reference voltage signal generating means. The second comparing means compares the output voltage of the light receiving sensor with a second reference voltage, and outputs one of the binarized output signals when two or more sheets of printing paper are passing in an overlapped manner; The other of the binarized output signals is output when no printing paper is passing or when a single layer of printing paper is passing.

Further, when one of the binarized output signals from the first comparison means is input to the first and second comparison means, the binarized output signal from the second comparison means is inputted to the first and second comparison means. When one of the signals is input, a multiplex sending signal is output, and the first
and multiplex feed signal output means for stopping output of the multiplex feed signal when the other of the binarized output signals from the comparing means is input.

[Operation] The present invention was made by focusing on the fact that there is inevitably an area at the front end of printing paper that cannot be printed.

That is, as indicated by reference number 12 in FIG. 4, there is an area at the front end of the printing paper 10 where printing is not performed. This region 12 is called a "grip" and is an essential region for conveying the printing paper 10 by the printing machine. The width X of the region 12 is usually about 5ffl1m to about 101m.

Since the area 12 cannot be printed, it is always the ground color of the printing paper 10. Therefore, if multiple feeding can be detected only in area 12, regardless of the printing paper portion after area 12, multiple feeding of printing paper can be reliably detected regardless of the type of paper and the printing frequency. Can be done.

The present invention is provided with the above characteristic configuration based on the above considerations. That is, the first comparison means outputs one of the binarized output signals when one or more sheets of printing paper has passed, and outputs the other output signal when no printing paper has passed. . In addition, in the second comparison means, one of the binary output signals is output when two or more sheets of printing paper are passing, and when no printing paper can pass and when one printing paper is passing, one of the binarized output signals is output. While passing, the other of the binarized output signals is output. and,
In the multiple feed signal output means, when one of the binarized signals from the first comparison means is input, that is, when the printing paper is passing, the multi-feed signal output means outputs the binarized signal from the second comparison means. When one of the output signals is input, that is, when two or more sheets of printing paper are passing like lightning, a multiple feed signal is output. Then, this multiple feed signal is no longer output when the other of the binarized signals is input from the first comparison means, that is, when the passage of the printing paper is completed.

Therefore, when one of the binarized output signals is output from the second comparison means and a multiple feed signal is output, the multiple feed signal is applied to the printing paper regardless of the area behind the printing paper. This is maintained until the passage of the paper is completed, so multiple feeding is detected without being affected by the presence or absence of a printed pattern formed on the printing paper.

[Effects of the Invention] Therefore, according to the present invention, it is possible to obtain a printing paper multiple feeding detection device that can accurately detect multiple feeding of printing paper regardless of the presence or absence of a printed pattern and regardless of the thickness of the paper. . With the printing paper multiple feeding detection device of the present invention, it is only necessary to set the first reference voltage and the second reference voltage according to the thickness and background color of the printing paper, so it is easy to use even when the printing paper changes. can be adjusted to Therefore, there is no need for complicated adjustment work as in the case of using a conventional photoelectric multiple feed detection device. Also,
Unlike detection devices using microswitches, there is no malfunction when the paper is thin, and there is no problem of contact wear.

Note that the multiple feed detection device of the present invention can be used not only for ordinary printing machines but also for paper feeding mechanisms of dry type copying machines. Similarly, it can also be used in bookbinding machines (T-folding machine, folding machine, slitter sewing machine, etc.) that handle sheets of multicolored paper. Further, the printing paper is not limited to paper, and can also be used when printing on a resin sheet or the like.

[Description of Embodiment] FIG. 1 is a circuit diagram of a printing paper multiple feed detection device according to an embodiment of the present invention. The light receiving sensor 21 is combined with an arbitrary light source, and is placed at a position where it can receive the light transmitted through the printing paper being passed, like the light receiving element 7 shown in FIG. . The light receiving sensor 21 can be constituted by any photoelectric conversion element such as a phototransistor.

The light receiving sensor 21 includes a first comparator 22 as a first comparing means and a second comparator 23 as a second comparing means.
The output signal of the light receiving sensor 21 is connected to the first
and is applied to one input terminal of the second comparison F22.degree.23.

Further, a variable resistor 24 is used as a first reference voltage signal generating means.
is connected to the other input terminal of the first comparator 22. The first reference voltage set by this variable resistor 24 is lower than the output voltage of the light receiving sensor 21 when no printing paper is passing through, and the output voltage of the light receiving sensor 21 when only one printing paper is passing through. is set higher than. Therefore, the first comparator 22 compares the output voltage of the light receiving sensor 21 and the first reference voltage given by the variable resistor 24, and outputs a "high" output signal when no printing paper is passing through. Outputs a "low" output signal when one or more sheets of printing paper is passing.

On the other hand, the other input terminal of the second comparator 23 also has a variable resistor 2 as second reference voltage signal generating means configured in the same manner.
5 provides a second reference voltage. The second ls quasi-voltage is the magnitude of the output voltage value of the light receiving sensor 21 when one sheet of printing paper passes and the value of the output voltage of the light receiving sensor 21 when two or more sheets of printing paper pass. has been selected. Therefore, the second comparator 23 outputs one of the binarized output signals, which is the ro-J signal in this embodiment, when two or more sheets of printing paper overlap and pass through.

On the other hand, when no printing paper is passing or when one printing paper is passing, a "high" signal is output.

The first comparator 22 and the second comparator 23 are connected to a D-type flip-flop circuit 26 as multiplexed signal output means of the present invention. That is, the first comparator 2
2 is connected to the reset input terminal of the D-type flip-flop circuit 26 via an inverter 27. Further, the clock input terminal of the D-type flip-flop circuit 26 is connected to the first comparator 22 via an inverter 28 J3 and a delay circuit 29.

The two delay circuits are not an essential configuration, as will be explained later.
For example, it can be configured with an appropriate circuit as shown in FIG.

On the other hand, the second comparator 23 is connected to the data input terminal of a D-type flip-flop circuit 26 via an inverter 30.

Note that a first display 32 is connected to the first comparator 22 via an inverter 31, and a first display 32 is connected to the first comparator 22 via an inverter 31.
A second display 34 is connected via an inverter 33 to. The first indicator 32 and the second indicator 34 are provided to indicate, respectively, that one sheet of printing paper is passing and that two or more sheets of printing paper are passing. It is something that exists. However, the information obtained on the second display 34 is not correct, but is similar to the output of the conventional photoelectric multiple feed detection device shown in FIG. 3 described above. That is, if there is a dark pattern area on the printing paper, such as the pattern area 8 shown in FIG. 4, it will be erroneously displayed that two or more printing papers are being fed.

However, this second indicator 34
This is provided to adjust the voltage and set the second reference voltage. That is, before using the multiple feed detection device of this embodiment, the value of the variable resistor 25 is adjusted to such an extent that the second display 34 indicates that two sheets of printing paper overlap. It is something that exists.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

In the multiple feed detection device of this embodiment in which the first drive voltage and the second drive voltage are set as shown in j-e above, in the initial state, since the printing paper is not passing, the first comparator 22 outputs a “high” signal. Therefore, the output signal is inverted by the inverter 27, and the reset input terminal of the D-type flip-flop circuit 26 is supplied as shown in FIG.
), a "low" signal is input as shown to the left.

Similarly, the clock input terminal of the D-type flip-flop circuit 26 is inverted by an inverter 28 and is also connected to a delay circuit 29.
A “low” signal delayed by
).

On the other hand, the second comparator 23 also outputs a "high" signal in the initial state where no printing paper is passed through, and the cough signal is inverted by the inverter 30, so that the data input terminal of the D-type flip-flop circuit 26 is A "low" signal shown on the left side of FIG. 5(C) is input.

Next, when a sheet of printing paper begins to pass above the light-receiving sensor 21, the intensity of the light incident on the light-receiving sensor 21 decreases, and therefore the output voltage of the light-receiving sensor 21 decreases. 1st
Since the reference voltage is set higher than the output voltage of the light receiving sensor 21 at this time, the first comparator 22 outputs a "low" signal. Therefore, the "high" output inverted by the inverter 27 is input to the reset input terminal of the D-type flip-flop circuit 26 (see FIG. 5(a)).
.

At this time, since the delay circuit 29 is provided, a "high" signal is input to the clock input terminal of the D-type flip-flop circuit 26 after being delayed by the delay circuit 29.

On the other hand, on the second comparator 23 side, the second reference voltage is higher than the output voltage of the light receiving sensor 21 when two or more sheets of printing paper are passing; Since the output voltage is set lower than the output voltage of the light receiving sensor 21, the "high" output signal is maintained as in the initial state. Therefore, as shown in FIG. 5(C), a "low" signal continues to be input to the data input terminal of the D-type flip-flop circuit 26.

The D-type flip-flop O-tub circuit 26 outputs a multiplexed signal only when the signal input to the clock input terminal changes to "high" and the signal input to the data input terminal is in the "high" state. Therefore, when one sheet of printing paper is passing, the signal input to the data input terminal remains "low" as shown in Figure 5 (C), so multiple feeding is not possible. No signal is output.

In addition, the signal applied to the reset input terminal is as shown in FIG.
), the state changes to "low" as soon as one sheet of printing paper passes, so after one sheet of printing paper passes, it returns to the initial state again.

Next, an explanation will be given of the operation when printing sheets overlapped 2!11 pass from the above-mentioned initial state. In this case, the first
On the comparator 22 side, the first reference voltage is set higher than the output voltage of the light-receiving sensor 21 when one or more sheets of printing paper is passing. Even when passing through, the D-type flip-flop circuit 26°
A signal changing from "low" to "high" is applied to the reset input terminal of (FIG. 6(a)). Then, a "high" signal is input to the reset input terminal until the double layered printing paper passes above the light receiving sensor 21.

Similarly, a delay circuit 2 is connected to the clock input terminal of the D-type flip-flop circuit 26, as shown in FIG.
9, a signal that rises slightly later than the signal applied to the reset input terminal is input (see Fig. 6 (b)).
')reference).

On the rough second comparator 23 side, the second reference voltage is
Since the output voltage is set higher than the output voltage of the light receiving sensor 21 when two or more sheets of printing paper pass in an overlapping state, the second comparator 23 outputs a "low" signal unlike the initial state. do. Therefore, the "high" signal inverted by the inverter 30 is input to the data input terminal of the D-type flip-flop circuit 26 (see FIG.
)reference).

Therefore, the D-type flip-flop circuit 26 outputs a multiplexed output signal when the input signal applied to the clock input terminal rises and the signal applied to the data input terminal is "high". , Figure 6 (d
), it outputs a "high" signal at the same time as the signal applied to the clock input terminal rises. and,
This state is maintained until reset, ie, until the signal applied to the reset input returns to the "low" state. Therefore, the output indicating multiple feeding is maintained until the two stacked sheets of printing paper finish passing through, regardless of the intensity of the light incident on the light receiving sensor 21 in the area behind the printing paper. become.

It should be noted that the delay circuit 29 does not need to be provided. That is, the delay circuit 29 is configured so that, as shown in FIG.
If the printing paper 42 passes while being shifted in the front direction by the distance indicated by (when the printing paper 42 is sent with a delay of time t1), an output based on only one printing paper, that is, a multiple feed signal is output by mistake. This is provided to prevent the clock input from occurring with a delay of, for example, a time °C when the signal applied to the data input terminal changes as shown by the dashed line in Figure 6(C). This is provided to reliably detect multiple sending even if the signal applied to the end changes. Therefore, even if a large number of sheets of printing paper are overlapped to be supplied to a printing machine, there is no possibility that the sheets will shift in the front direction as shown in FIG. 8, or the amount of shift can be ignored. In the case where the delay circuit 29 is small, the delay circuit 29 may not be provided.

Further, in the above-described embodiment, the D-type flip-flop circuit 26 was used as the multiplexed signal output means, but an R8-type flip-flop circuit 52 may be used as a means for outputting multiplexed signals, for example, as shown in FIG. It can also be replaced by a logic circuit in combination with gate 51 and inverters 53 and 54.

In each of the above embodiments, one light receiving sensor 21 is used, but it is also possible to use two light receiving sensors and connect each to the first or second comparator 22, 23. It is.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a sectional view for explaining an example of a conventional printing paper multiple feed detection device, and FIG. 3 is a circuit diagram of a conventional printing paper multiple feed detection device. FIG. 4 is a cross-sectional view for explaining another example of the feed detection device, FIG. 4 is a plan view for explaining printing paper on which a pattern area is formed and an unprintable area, and FIG. FIG. 6 is a diagram for explaining changes in signals when two or more sheets of printing paper pass, and FIG. 6 is a diagram for explaining changes in signals when two or more sheets of printing paper pass in an overlapping state. , 7th
The figure is a circuit diagram showing an example of a delay circuit, and FIG. 8 is a diagram for explaining the function of the delay circuit, and is a perspective view showing a state in which two sheets of printing paper overlap in a state shifted in the front and back direction. FIG. 9 is a circuit diagram for explaining another example of the multiplexed signal output means. In the figure, 21 is a light receiving sensor, 22G is a first comparator as a first comparing means, 23 is a second comparator as a second comparing means, and 24 is a first reference voltage signal setting means. A variable resistor, 25G, is used as a second reference voltage signal generating means, and 26 is a D-type flip-flop circuit as a multiplexed signal outputting means. (2 others) Figure 5 (C) Input to rewab flow 1 - 71 - (xi > 7 Rewab flow 1 output car - J - 111 - -
---1--------Figure 7 Figure S Y

Claims (3)

[Claims] (1) a light-receiving sensor that is disposed in an area where printing paper passes and generates a voltage signal of a different magnitude depending on whether one printing paper is passing through or when two or more printing papers are overlapping; and first and second reference voltage signal generation means for generating a first or second reference voltage signal, respectively, in order to binarize the output signal of the light receiving sensor, and the first reference voltage signal is generated by printing. The second reference voltage signal is lower than the output voltage of the light receiving sensor when no paper is passing through, and higher than the output voltage of the light receiving sensor when there is one sheet of printing paper, and the second reference voltage signal is lower than the output voltage of the light receiving sensor when no paper is passing through. and the output voltage of the light receiving sensor in the case of two sheets, and is connected to the light receiving sensor and the first reference voltage signal generating means, and is connected to the output voltage of the light receiving sensor and When the printing paper is passing, one of the binarized output signals is output, and when the printing paper is not passing, the other of the binarized output signals is output. a first comparing means for outputting a signal; the first comparing means is connected to the light receiving sensor and the second reference voltage signal generating means, and compares the output voltage of the light receiving sensor and the second reference voltage; Outputs one of the binarized output signals when two or more overlapping sheets of paper are passing through, and outputs one of the binarized output signals when no printing paper can pass or when a single printing paper is passing. a second comparing means for outputting the other of the binarized output signals; and a second comparing means for outputting the other of the binarized signals; and a second comparing means for outputting the other of the binarized signals; When one of the binary output signals is input from the second comparing means, a multiplexed signal is output, and the other of the binary output signals is input from the first comparing means. A multiple feed detection device for printing paper, further comprising multiple feed signal output means for stopping output of an input multiple feed signal. (2) The multiplexed signal output means has a reset input terminal and a clock input terminal connected to the first comparison means, and the second comparison means has a reset input terminal and a clock input terminal.
The printing paper multiple feed detection device according to claim 1, which is a D-type flip-flop circuit whose data input terminal is connected to the comparing means. (3) The printing paper multiple feeding detection device according to claim 2, further comprising a delay circuit connected between the first comparing means and a clock input terminal of the D-type flip-flop circuit.