JPH0321960Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper feed safety device in a sheet-fed printing press.

[Conventional technology and its problems]

In general, a sheet-fed printing machine consists of a paper feed section, a printing section, and a paper discharge section. The paper is configured to be printed by a printing machine and delivered to a paper delivery unit.

In the above-mentioned sheet-fed printing press, the sheet fed from the paper feed section to the printing section may fall off when passing through the printing section, and this dropped sheet may not be printed. If the paper gets stuck in the printing press, the sheets sent later will also be jammed and unable to move forward, leaving no place to escape and eventually leading to a major accident such as eccentricity of the printing cylinder. Sometimes they get connected.

Therefore, it is necessary to confirm that the sheets fed from the paper feed section to the printing section have passed through the printing section and are securely ejected to the paper output section, thereby preventing paper jams inside the printing machine. It is desirable to be able to take immediate measures in response to such abnormal situations.

However, it is not only quite difficult to provide some sort of detection means to detect abnormal situations such as paper jams in the printing section due to space constraints, but it is also quite difficult to ensure reliability. That was the current situation.

[Purpose of invention]

In view of the above, this invention automatically issues an abnormality signal when paper fed from the paper feed section to the printing section falls off within the printing section and is not ejected normally, thereby preventing machine damage and accidents due to paper being caught in the paper. The purpose is to provide something that can prevent this from happening.

[Summary of the idea]

In order to achieve the above object, the paper feed safety device for a sheet-fed printing press according to the present invention includes a paper feed detector at the paper feed end of the printing section to detect the feeding of sheets into the printing section. A paper ejection detector for detecting the ejection of a sheet from the printing unit after printing is arranged at each edge of the paper, and the paper feed detector and the paper ejection detector are arranged so that the paper feed detector first connected to a memory delay circuit that generates an output signal by delaying a detection signal outputted by detecting a sheet of paper until the sheet passes through a printing unit and reaches a paper discharge detector; Based on the output signals of the paper discharge detector, which is enabled to operate according to the output signal of The apparatus is characterized in that it includes a determination circuit that generates an abnormality signal when a sheet is not detected at the predetermined timing.

[Effect]

According to the present invention configured as described above, if a sheet that first passes through the paper feed detection section and is fed to the printing section does not pass through the paper discharge detection section after a predetermined period of time has elapsed, an abnormality will occur. A signal is issued, and if the second and subsequent sheets do not pass through the discharge detection section at a certain timing after the first sheet passes through the discharge detection section, an abnormality signal is issued. With this, it is possible to constantly and reliably monitor abnormal situations such as paper jams and paper dropouts in the printing section. Moreover, since the paper feed detector and the paper discharge detector are installed at the paper feed end and the paper discharge end of the printing section, the installation space can be secured without being obstructed by the printing machine of the printing section.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, A indicates a paper feeding section, B a printing section, and C a paper discharging section. The paper feed section A has a paper feed device 1, and the sheets S in the paper feed device 1 are fed into the printing section B one by one by a paper feed conveyor 2.

In the illustrated example, the printing section B includes four printing units 3a, 3 for four colors for color printing.
A printing press 3 consisting of printing units 3b, 3c and 3d is provided, each printing unit 3a, 3b, 3c and 3d having a plate cylinder 4, a blanket cylinder 5, an impression cylinder 6 and a double cylinder 7.

Note that inside the printing press 3, sheets S fed at regular intervals are indicated by thick lines.

The paper discharge section C has a paper discharge conveyor 8, and the printed sheets S are stacked on a base plate 9 by this conveyor 8.

On the inlet side of the printing press 3, a paper feed detector 11 is located in a paper feed section A, and on the exit side, a paper discharge detector 12 is located in a paper discharge section C. It is located. These detectors 11 and 12 are
For example, it can be a photoelectric detector.

In the illustrated example, there are eight sheets S inside the printing press 3, and the number of sheets S corresponds to the number set on the counter of the safety device, as will be described later.

It goes without saying that the number of sheets S is merely an example.

In the above configuration, the sheet S whose feeding into the printing machine 3 is detected by passing through the paper feed detector 11 passes through the printing machine 3 at a predetermined timing and is detected by the paper discharge detector. If it is not detected in 12, printing machine 3
This means that the paper has become jammed or fallen out. This is detected as follows.

In FIG. 2, the detection signal in the paper feed detector 11 is transmitted to the set side terminal S of the first storage element 15a.
sent to. Accordingly, upon the start of paper feeding, the first memory element 15a outputs an output signal through input to the set side terminal S, and this output signal is input to the first AND element 16a. A pulse generator 17 generates pulse signals in accordance with the rotation of the plate cylinder 4 when the printing press 3 is in operation. The pulse signal generated by this pulse generator 17 is
AND element 16a and third AND element 16b
sent to. For example, one pulse signal or an appropriate number of pulse signals are generated per rotation of the plate cylinder 4.

When the pulse signal from the pulse generator 17 and the output signal from the first storage element 15a are input to the first AND element 16a, an output pulse is output from the first AND element 16a. 1st
is sent to the pulse counter 18a. When the pulse counter 18a detects a predetermined number of pulse signals, it outputs an output signal, and this output signal is input to the set side terminal S of the second memory element 19.

This second memory element 19 is configured to output an output signal from an output side terminal O in response to an input to its set side terminal S, and this output signal is output from the first memory element 19.
The first storage element 15 via the differential element 20a of
The reset side terminal R of a is sent, and the first pulse counter 18a is stopped by resetting the first memory element 15a.

The rotary pulse generator 17 generates a pulse signal corresponding to the paper feed interval to the printing machine 3 (for example, 1 pulse or 4 pulses for each sheet fed), so that the paper feed detector 11 detects when the first sheet is being fed. outputs an output signal after detecting paper feeding of the first storage element 1.
5a outputs an output signal, and when a pulse signal from the pulse generator 17 is input, the first AND element 16a outputs this pulse signal. When this output pulse signal is counted by the first pulse counter 18a by a number equal to the number of sheets S located in the printing press 3 (for example, 8 sheets in the illustration), this first pulse signal is counted by the first pulse counter 18a. Pulse counter 18a
outputs an output signal, whereby the second storage element 19 outputs an output signal from the output terminal O. This output signal is input to the reset side terminal R of the first memory element 15a as a signal differentiated by the first differentiating element 20a and is reset, thereby stopping the first pulse counter 18a. . However, the output from the second storage element 19 continues.

On the other hand, when an output signal starts to be output from the output terminal O of the second memory element 19, this output signal is also input to the control amplifier 21 of the photoelectric discharge detector 12, and is Control amplifier 21 starts operating. When the control amplifier 21 is activated, the circuit of the light projector of the discharged sheet detector 12 is connected to the power source, thereby enabling the discharged sheet detector 12 to operate.

In this way, the first memory element 15a and the first
A storage delay circuit is constituted by the AND element 16a, the pulse generator 17, the first pulse counter 18a, and the second storage element 19.

Therefore, the first pulse counter 18a counts the number of sheets S located in the printing press 3 from the start of paper feeding, and when a predetermined count is reached, outputs an output signal, and the control amplifier 21 is activated. When the first sheet S at the start of paper feeding is detected by the sheet discharge detector 12, the light from the emitter to the receiver is blocked by the sheet S. , no output signal is output from the control amplifier 21 to the second AND element 22.

However, the first sheet S is detected by the paper discharge detector 12.
If the sheet S is not detected by the control amplifier 21 (i.e., the paper is jammed or falls off), the sheet S does not pass through the discharge detector 12, and this detector 12 becomes conductive, causing the control amplifier 21 to output the second An output signal is output to the element 22 and inputted to one input side terminal of the second AND element 22.

Reference numeral 23 denotes a paper ejection detection timing pulse generator that constitutes a determination circuit together with the second AND element 22. After the first paper ejection is detected, a pulse signal is sent to the other side of the second AND element 22 at a predetermined timing. is sent to the input terminal of Therefore, the paper discharge detector 1
2 does not detect paper, the second AND element 22
an input signal entering the timing pulse generator 22;
and the input signal entering the second AND element 22, the second AND element 22 produces an output signal. This output signal activates a suitable warning device and the shell is removed.

From the paper discharge detection timing pulse generator 23,
As described above, the pulse signal continues to be sent to the second AND element 22 at a predetermined timing, and on the other hand, the second memory element 19 continues to output an output signal as long as the paper feed detector 11 detects paper feeding thereafter. The control amplifier 21 continues to operate. Then, the second and subsequent sheets S
If the paper is not detected by the paper discharge detector 12 at a predetermined timing, an output signal is output from the second AND element 22 to notify of a paper jam or dropout inside the printing press 3.

The paper discharge detection timing pulse generator 23 includes:
Like the pulse generator 17, it outputs a predetermined pulse signal (usually one pulse) for each revolution of the plate cylinder 4, and a second AND element is generated each time a sheet S passes the discharge detector 12. It is configured to send a pulse signal to 22.

Note that the paper ejection detection timing pulse generator 23 can be omitted and the pulse generator 17 can also be used, but in the illustrated example, both the pulse generators 12, 2
3 as separate units, a pulse generator 17 outputs a plurality of pulse signals per rotation, and a paper discharge detection timing pulse generator 12 outputs one pulse signal per rotation. It is possible to deal with the case where the number of sheets of paper located between 11 and 12 does not correspond to an integral number of stages.

Next, the operation when the sheet feeding is completed and the sheet feeding detector 11 no longer detects the sheet S will be described.

While the paper feed detector 11 does not detect the paper feed of the sheet S, it gives an input signal to the set side terminal S of the third memory element 15b, while the pulse generator 17 outputs a constant pulse signal. Third AND element 16b
has been entered. In this state, when the first pulse signal after paper feeding is completed is input to the third AND circuit 16b, the third
By inputting a signal to the set side terminal S of the memory element 15b, an input signal is given from this memory element 15b to the third AND element 16b. For this reason,
The third AND element 16b outputs an output signal, and this signal is input to the second pulse counter 18b,
When this pulse counter 18b finishes counting the aforementioned predetermined number (for example, 8), this pulse counter 18b outputs an output signal. Then, this output signal is sent to the reset side terminal R of the second storage element 19.
is input to the output terminal O, and puts it into a reset state to stop the output from the output terminal O. Then, from this other output side terminal N, the second differential element 20b
to the reset side terminal R of the third memory element 15b.
An input signal is input to the memory element 15b, and the input signal is put into a reset state to stop the output of the third storage element 15b, thereby also stopping the second pulse counter 18b.

As a result, this second pulse counter 18b
stops the operation of the control amplifier 21 after counting the number of pulses corresponding to the number of sheets S until the last sheet S reaches the sheet discharge detector 12 from the sheet feed detector 11;
The second memory element 15b is reset to return everything to its initial state.

[Effect of idea]

Since the present invention has the above-mentioned configuration, it is possible to constantly and reliably monitor abnormalities such as paper jams and falling off in the printing section of a sheet-fed printing machine, thereby preventing abnormalities such as paper jams from occurring. When this occurs, it is possible to quickly take action and prevent major accidents such as damage to the printing press due to the entrainment of fallen sheets, printing on the cylinder, and even eccentricity of the cylinder of the printing press.

Moreover, the paper feed detector and paper ejection detector are installed at the paper feed end and paper ejection end of the printing section, so this installation space can be secured without being obstructed by the printing machine in the printing section. There is a certain effect.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a sheet-fed printing press equipped with an embodiment of the present invention, and FIG. 2 is a block diagram showing a control system of the paper feed safety device according to the present invention. 3...Printing machine, 11...Paper feed detector, 12...
Paper discharge detector, 15a, 15b, 19... Memory element, 16a, 16b, 22... AND element, 17
...Pulse generator, 18a, 18b...Pulse counter, 20a, 20b...Differential element, 21...
Control amplifier, 23...Sheet discharge detection timing pulse generator.

Claims (1)

[Claims for Utility Model Registration] 1. A paper feed detector for detecting the feeding of a sheet into the printing section at the paper feeding end of the printing section, and a paper feed detector for detecting the feeding of the sheet into the printing section at the paper discharging end of the printing section. In addition to disposing paper ejection detectors for detecting the ejection of paper from each paper, the paper feed detector and the paper ejection detector are connected to each other, and a detection signal outputted when the paper feed detector detects the first sheet is detected by the paper feed detector and the paper ejection detector. The ejector is connected to a memory delay circuit that generates an output signal by delaying the sheet until it passes through the printing section and reaches the ejector detector, and is activated by the output signal of the memory delay circuit. Based on the output signal between a paper detector and a paper ejection detection timing pulse generator that generates a pulse signal at a predetermined timing in accordance with the ejection of a sheet, an abnormality is detected when a sheet is not detected at the predetermined timing. A paper feed safety device for a sheet-fed printing press, comprising a determination circuit configured to generate a signal. 2. The memory delay circuit includes a first memory element that outputs an output signal upon detection of the first paper feed by the paper feed detector, and a pulse generator that generates pulses in response to rotation of the printing press. , an AND element that outputs a pulse signal when receiving outputs from both the pulse generator and the first storage element;
A pulse counter that outputs an output signal when a predetermined number of pulses from the AND element is counted, and a second pulse counter that receives the output of this counter and outputs a signal that enables the circuit of the paper discharge detector to operate. A paper feed safety device for a sheet-fed printing press according to claim 1, characterized in that the device comprises a memory element. 3. Utility model registration claim 2, characterized in that the first memory element is reset by the output signal of the second memory element.
Paper feed safety device for sheet-fed printing presses as described in Section 1.