JPS63290746A - Detection method for sheet-overlapping in sheet-fed press - Google Patents

Abstract

PURPOSE:To ensure the detection of sheet-overlapping, by a method wherein, an intermediate value between an output level of a receptor with two sheets overlapped and a reference level is calculated, and a discrimination level is determined according to the intermediate value. CONSTITUTION:A processing part 1 made of processor, memory, etc., issues a pulse to a counter 4 to makes it perform a calculation, stores the count value in a light amount memory 5, transmits data to an amplifier 7 to drive a light projector 8, and determines a light-emitting amount. On the other hand, an electrical output level of a receptor 10 receiving a beam from the projector 8 through a sheet 9 is converted to a digital signal, and the processing part 1 reads the data to compare it with a reference level from an FLS 3, performs a predetermined calculation, stores the obtained discrimination level in a level memory 13, compares the discrimination level in the ML 13 with the data from an ADC 12 to detect whether the sheet 9 is single or plurally overlapped. If overlapping is detected, the processing part 1 issues the detected data through an output part 14 to control a sheet feeder and a printing press to be stopped. Therefore, the sheet-overlapping can be stably and surely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for photoelectrically detecting the overlap of sheets, called sheets, supplied to a sheet-fed printing press.

[Conventional technology]

When feeding paper from a paper feeder to a sheet-fed printing machine, the front edge of the paper should come into contact with a stopper called a front stopper installed at the tip of the paper feed tray on the printing machine side, and then the paper should be printed. At this time, in order to prevent two or more sheets of paper from being fed redundantly at the same time, a projector is usually installed on the back side near the front of the paper feed tray, and a A through hole is drilled in the opposing paper feed table, and a light receiver (5) is provided on the upper surface of the liquid feed table of the through hole, and the light beam from the emitter that passes through the paper is received by the receiver. and convert it into an electrical signal,
This output level is compared with a preset discrimination level, and based on this result, duplication of sheets is detected.

However, the amount of light emitted by the projector and the discrimination level need to be set appropriately according to the thickness of the paper, color printing, etc.1.The first method is to keep the discrimination level constant and to set the discrimination level for one sheet of paper. The power supplied to the emitter is adjusted by assuming that the discrimination level is between the output level obtained from the receiver when there are two sheets of paper and the output level obtained from the receiver when there are two sheets of paper. The second method is to determine the power to be supplied to the floodlight, and thereby set the amount of light emitted to a constant value. For each output level of the photoreceiver, the discrimination level is set to a value that falls between the two.

[Problem that the invention seeks to solve]

However, when a light bulb is used as a floodlight, the relationship between the power supplied to the floodlight and the amount of light emitted is linear in the range where the light intensity is large or small, but becomes non-linear in the middle range. In the first method, in the case of thin paper or thick paper, the discrimination level can be set as a relationship between the output levels of one sheet and two sheets of paper, but for medium-thick paper normally used, (Due to the relationship between the power supply and the illumination pattern, a non-linear section is used), the discrimination level is not intermediate, and the amount of light transmitted due to changes in the amount of light transmitted due to "gap" of the paper etc.
This causes a problem that the detection situation becomes unstable.

In addition, in the second method, due to the relationship between the amount of light received by the receiver and the output level, the range of high light intensity is saturated, so there is no problem with thick paper and medium thick paper, but with thin paper Since non-linear parts are used, the output level difference between one sheet and two sheets is small, so the difference between the discrimination level and the detection level is also small. When performing detection using a digital circuit, high stability is required, and when using a digital circuit, high precision is required for the resolution when converting the output of the photoreceiver into a digital signal, and in both cases, the circuit configuration is expensive. This is causing a problem.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention is constructed by several means.

That is, in the method for detecting paper overlap described above, a reference level is set according to the amount of light received by the light receiver, the output level, and the output level of the light receiver corresponding to the range in which the FILL coefficient is linear, and Find the power supplied to the emitter that makes the output level of the receiver equal to the reference level when there is one sheet of paper, and set the amount of light emitted by the emitter using this supplied power. An intermediate value between the output level and the reference level is found, and the discrimination level is set based on this intermediate value.

[For production]

Therefore, the output level obtained from the receiver when there is one sheet of paper and the same output level when there are two sheets of paper are both linear due to the relationship between the amount of light received by the receiver and the output level. Since the discrimination level is set within the target range and in the middle of these, the amount of light emitted and the discrimination level are optimally determined depending on the paper actually used.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 2 is a block diagram showing the configuration. It includes a processor such as a microprocessor (hereinafter referred to as CPU) and a processing unit (hereinafter referred to as PH1) 1 that includes memory, etc., and also provides instructions to it. keyboard (hereinafter referred to as KB)
) 2 and a reference level setter (hereinafter referred to as FLS) 3 using a digital switch etc.
The counter (hereinafter referred to as CUT) 4 is sent a pulse to register the count value, and the count value is finally stored in the light weight memory (hereinafter referred to as υ5), and the contents are digitally stored.・Analog converter (hereinafter referred to as DAC)
6)) is converted to an analog signal, and then an amplifier (hereinafter referred to as
A) The electrical output of the light receiver 10 which drives the light emitter 8 with the amplified output sent to the light emitter 7 and determines its emission intensity, while receiving the light beam from the light emitter 8 that has passed through the paper 9. The level is amplified by A11, the output is converted to a digital signal by an analog-to-digital converter (hereinafter referred to as ADC) 12, and this data is read and converted to FLS.
Compare it with the reference level from step 3, perform a predetermined calculation, and store the discrimination level obtained by this calculation in the level memory (
Hereafter, store it in ML) 13, and from now on, ML13
Compare the discrimination level inside and the data from ADC12,
Detects whether the paper 9 is one or two or more sheets,
If duplication is detected, the detection information is sent out via the output unit (hereinafter referred to as OPD) 14, and the paper feeding device and printing press are stopped and controlled.

Note that the PH 11 and the CPU execute the instructions stored in the memory in the PH 11, and perform the aforementioned comparison, calculation, control, and other processing while accessing the memory for necessary data.

FIG. 1 is a flowchart of the processing status by the CPU in PR81, which is performed on the premise of the relationship between the amount of light received by the light receiver 10 V and the output level L shown in FIG.

That is, first, insert one sheet of paper 9 and write this to KB2.
When you issue a command to operate , “1 sheet of paper?” 101 becomes Y (
YES), and in response to this, the count value rc of CUT4 is cleared by OJ102. After clearing CUT4, CU
Send a pulse for counting to T4 and write ``c=c+I J
103, and controls the DAC6 to set the count value of CUT4 via Mv5.
Converter 111 converts the signal into a digital signal, which is then applied to A7.

Then, the output of A7 is supplied to the projector 8 as voltage or current power according to the count value of the CUT 40, which emits light according to the supplied power, and the emitted light passes through the paper 9 and receives light. The light is received by the device 10, becomes an electrical signal with an output level corresponding to the amount of light received, is amplified by All, and then is given to the ADC 12.

In ADC12, All
The output of is converted into the digital signal data D0 by the ``transform conversion'' 112, so the CPU of the PH11 reads this data by the ``read'' 113, and also reads the reference level data by the FLS3. Do 114 in the same way and l'-01ki DF? J
121 is compared, and while this is N (NO), steps 103 and subsequent steps are repeated, and if step 121 is Y, "punishment ← Cl 122, store the count value C of CUT 4 in MV5". do.

Note that the reference level data DF by FLS3 is the third
As shown in the figure, the relationship between the amount of received light V and the output level L is saturated in a large part of the amount of received light V and is non-linear, and the linear range excluding this part corresponds to the light receiver. According to the output level L of 10, for example, the output level Ll
It is set according to the following.

Therefore, when step 121 becomes Y, the data input corresponds to the output level L0, and the count value C of the counter 4 indicates the power supplied to the projector 8 corresponding to the light receiving unit MV in FIG. From then on, the amount of light emitted by the projector 8 is set in accordance with this count value C.

Next, when paper 9 is set to 2 sheets and this command is given in the same way as in step 101, "2 sheets of paper? J 131 is Y," and "reverse conversion" 132 converts the output of All to ADC.
12, the data is converted in the same manner as in step 112, and this data "D2 Read" 133 and the reference level data "DF Read J134t-Step 1" from FLS3 are converted.
13, 114 and using these “Ds=
(Dy”Ds)/2 J 141 calculates the intermediate value Ds between the reference level data D, the output level L when there are two sheets of paper 9, and the corresponding data D, and calculates this as l. '-ML4-DSJ 142 is used to store it in the ML13, and its contents are used as the discrimination level Ls in FIG. 3.

That is, in both the case of thin paper shown in FIG. 3 (4) and the case of thick paper shown in FIG.
When the amount of light emitted from the emitter 8 that is generated as transmitted light is set, and when there are two sheets of paper 9, the amount of transmitted light decreases for the same amount of light emitted, and the amount of light received by the light receiver 10 increases to V. , correspondingly, the output level becomes L3, but the discrimination level L8 obtained by the calculation in step 141 is an intermediate value between the output levels L1 and LB, so the discrimination level Ls
The difference between the output level L and the output level L is equal to y, and a sufficient difference value is maintained.If the output level L is equal to or higher than the discrimination level Ls, one sheet of paper 9 is produced, and the output level L is If the determination level L8 is ungrooved, stable detection can be performed as there are two or more sheets of paper 9.

The same is true when medium-weight paper is used, and regardless of the size, thickness, color, etc. of the paper 9, the illumination view of the projector 8 and the discrimination level Ls are always automatically set as optimal. .

Therefore, it is not necessary to make the resolution of the ADC 12 particularly high precision, and the number of bits of the digital signal can be reduced, so the overall configuration can be simplified and the cost can be reduced, and the duplication of the sheets 9 can be ensured. can be detected quickly and stably.

However, in addition to a light bulb, various light-emitting elements may be used for the projector 8, and various light-receiving elements may be used for the light receiver 10, and the reference level L8 can be determined according to this characteristic. good.

Also, a latch circuit or the like may be used for MY5, or the output of CUT4 may be directly given to DAC6, and the memory in PH1l may be used as MY5 and ML13, and OP[)14 may be omitted in some cases. It is also possible to make various modifications.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the discrimination level for the amount of light emitted from the emitter and the output level of the receiver is automatically set as the optimum level, so that the detection status of paper duplication is stable and reliable. A remarkable effect can be obtained in detecting paper duplication in sheet-fed printing presses.

[Brief explanation of drawings]

The figures show an embodiment of the present invention; Fig. 1 is a flowchart showing the processing situation, Fig. 2 is a block diagram showing the configuration, and Fig. 3 is a diagram showing the relationship between the amount of light received by the light receiver and the output level. be. 1...PH1 (processing section), 2...KB (keyboard), 3...FLS (reference level setter), 4
--- CUT (counter), 5... MY (light amount memory), 6... DAC (digital/analog converter), 8... Emitter, 9... Paper, 10...・
...Receiver, 12...ADC (analog-digital converter), 13...ML (level memory), ■
...Amount of received light, L...Output level, Ls ・
...Discrimination level.

Claims (1)

[Claims] It is equipped with a light emitter and a light receiver that receives the light beam from the light emitter that has passed through the paper and converts it into an electrical signal, and compares the output level of the light receiver with a preset discrimination level and determines whether the paper is In a method for detecting duplicates,
A reference level is set according to the output level of the light receiver corresponding to a range in which the relationship between the amount of light received by the light receiver and the output level is linear, and the output of the light receiver when there is one sheet of paper is set. The power supplied to the light emitter such that the level and the reference level are approximately equal is determined, and the amount of light emitted by the light emitter is set based on the supplied power, and the output level of the light receiver when there are two sheets of paper and the reference level are determined. 1. A sheet duplication detection method for a sheet-fed printing press, characterized in that a value intermediate between the two levels is determined and the discrimination level is set based on the intermediate value.