JPS60177206A - Double sheet detector for sheet-fed rotary press - Google Patents

Abstract

PURPOSE:To enable sure detection by storing the subtracted value indicating the quantity of the light transmitted through the half-sheet part of paper into a memory, subtracting said value from the quantity of the light transmitted through paper, determining the same as a reference value and comparing the reference value with the quantity of the light transmitted through the present paper. CONSTITUTION:The output from a photodetector LR is applied to a processing part PRS and is converted to the digital signal indicating the quantity of transmitted light and thereafter said signal is applied via an interface I/F and data bus to a processor CPU. On the other hand, the output from the photodetector LR is also applied to a paper detecting circuit PD and when said output attains a prescribed level or below, the circuit generates an output and applies the same to the interface I/F. The timing signal based on the output from a detector TD is also applied to the interface I/F. The processor CPU makes prescribed calculation and comparison operations by responding to the coincidence of both signals. The detection output DO for the double sheets is transmitted via the interface I/F and an output circuit OC such as a driver according to the result of such operations.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a two-sheet difference detection method used in a sheet-fed rotary printing press to detect that two or more sheets of paper are fed simultaneously.

[Prior art]

In sheet-fed rotary printing presses, when two or more sheets of paper are fed at the same time and a two-sheet difference occurs, this is detected and the operation of the printing press is stopped. A method whose principle is shown in FIGS. 3 through 3 was generally adopted.

That is, Figures 1 to 3 show the relationship between the light transmittance α of paper and the visibility of transmitted light.When there is only one sheet of paper, the relationship D=α as shown by straight line A. On the other hand, when there are two sheets of paper, the relationship is pD-α with curve B, so the method focuses on changes in the amount of light and detects the difference between the two sheets according to this value. It becomes.

However, in Fig. 1, the detection level Ld, which is semi-fixed according to the thickness and quality of the paper, is used as a reference, and the difference between two sheets is detected based on this.
The detectable range DE is small, the detection level Ld must be adjusted each time the type of paper is changed, and it is not possible to respond to changes in conditions over time.

In addition, in Fig. 2, processing such as averaging is performed on the amount of transmitted light up to the previous time, and the detection level Ld is set after memorizing the results.Comparing with Fig. 1, the detectable range DE is large, but it has the disadvantage that it is impossible to detect the difference between two sheets in a range close to 100% and a range close to 0% of the transmittance α.

In addition, in FIG. 3, the detection level Ld is set at a constant ratio to the stored value in the same way as described above.
Although the detectable range DE is expanded in FIG. 2, there is a drawback that it is impossible to detect the difference between two sheets in a range where the transmittance α is close to 100 or more.

As a countermeasure against this problem, a separate application filed by the present applicant entitled "Two-sheet difference detection method for sheet-fed rotary printing presses" (patent application No. 57-21499) is available.
4) has been proposed, and the PL can detect the difference between two sheets at a transmittance of 0-100%, but this method requires an arithmetic unit, a comparator, a subtraction value generator, etc., and the configuration is The disadvantage is that it becomes complicated.

[Summary of the invention]

The purpose of the present invention is to fundamentally eliminate the drawbacks of the conventional technology, and the amount of transmitted light transmitted through one sheet of paper and the amount of transmitted light transmitted through two sheets of paper are between two values. A memory that stores a value indicating the difference between the intermediate value indicating the value of - Provides a digital converter and a processor that performs predetermined calculations and comparisons using the value read from the memory according to the output of the converter and the value according to the output of the analog-to-digital converter, and has a simple configuration. 2 highly effective sheet-fed rotary printing presses that achieve this purpose.
This provides a sheet difference detection method.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to figures showing examples, but first a detailed description of the present invention will be given.

FIG. 4 is a diagram similar to FIGS. 1 to 3, but shows a straight line A indicating the amount of transmitted light transmitted through one sheet of paper, and a light amount Dα of transmitted light transmitted through two sheets of paper. An intermediate value M is determined between the curve B indicating -α2 and the curve indicating D=α-1, -, and a subtraction value indicating the difference between the value of the straight line A and the intermediate value M is determined. Then, the reference value M is determined by subtracting the subtraction value from the amount of light transmitted through the actual paper, and this is used as the detection level Ld.

Therefore, the subtraction value Ln is set according to the amount of transmitted light Dn that has passed through the previous paper, and the reference value Mn is sequentially determined by calculating Dn-Ln:Mn. The amount of transmitted light Dn+1 is compared with Mn≧Dn
If it is determined that the +1 condition has been met, the detectable range DE
is expanded by approximately 0% to 100%t of the transmittance α.

In addition, the subtraction value Ln set according to the light amount Dn is used as a reference value, and the light amount Dn+ corresponding to the current paper is calculated.
Even if the difference S from 1 is calculated by calculating Dn Dn+1 = S, the reference value Ln and S are compared, and it is determined that the condition of S≧Ln is satisfied, the same result as y can be obtained.

However, as shown by the dotted line), almost the same result can be obtained even if the intermediate value M is approximated by a straight line depending on the range of the transmittance α.

In addition, as shown in Fig. 5, which shows an enlarged view of the range of low transmittance α, for paper with low transmittance α, when there is a difference between two sheets, the curve B based on the theoretical value is
Since the curve Br based on the actually measured values shows a low value, it is preferable to change the reference value M to Mr for paper with a low transmittance α, and set the subtraction value and the reference value accordingly.

In addition, in the same figure, Ad, Md, Bd, etc. show changes when quantized by digital conversion.

From FIG. 6 onwards, examples will be shown based on the above principle.
The figure is a mechanical configuration diagram, in which the paper 2 sent out from the paper feed tray 1 is fed onto the difference plate 3, the head of the paper is captured by the swing claw 4, and the paper 2 is moved between the blanket cylinder 5 and the impression cylinder 6. A through hole 3a is bored in the vicinity of the tip of the difference plate 3. Light emitted from a light emitter LG provided on the lower surface of the plate 3 is transmitted through the paper 2, is received by a light receiver LR, and is converted into an electrical signal.

In addition, the impression cylinder 6 is provided with a driving body such as a protrusion (not shown in the figure), and the rotation of the impression cylinder 6 is detected by a detector TD such as a proximity switch installed opposite to this, and the rotation of the printing press is detected. A synchronized pulse signal is obtained.

FIG. 7 is a block diagram showing the electrical configuration, in which the light emitter LG is lit by the light source power source LPS, while the light receiver L
The output of R is given to a processing unit PR8, where it is converted into a digital signal indicating the amount of transmitted light, and then given to a processor CPU such as a microprocessor via an interface I/F and a data bus DB. .

On the other hand, a paper detection circuit P using a Schmitt trigger circuit etc.
The output of the light receiver LR is also given to D, and when this output becomes below a predetermined level, the paper detection circuit PD generates an output, which is given to the interface I/F, and
Timing signal generator TS based on the output of detector TD
The timing signal generated by G is also connected to the interface I/F.
If given to processor CP, the agreement between the processor CP
U responds, performs predetermined arithmetic and comparison operations, and according to the results, outputs the detection force Do of the difference between the two sheets through the interface I/F and output circuit OC such as a driver. .

Note that the processor C'PU is a data bus DB.

The system executes instructions in the fixed memory ROM connected via the address bus AB and control path CB, and performs various operations while accessing the required data to the similarly connected variable memory RAM. , regulates the operation timing of the processing unit PR3, controls the light source power supply LPS according to the output of the changeover switch SW operated according to the type of paper 2, varies the luminous intensity of the light source LG, and performs judgment and A predetermined range of control is established.

FIG. 8 is a block diagram showing details of the processing unit PR8, in which the output of the photodetector LR is amplified to a predetermined level by the amplifier AMP after the noise component is removed by the p-wave generator FIL. It is averaged by an averaging circuit AVR using an integrating circuit, etc., and then an analog-to-digital converter (hereinafter referred to as
A/D (ADC) is converted into a digital signal in response to a control signal from the processor CPU via an interface I/F.

In addition, the variable memory IJRAM stores subtraction values or reference values depending on the amount of light.
The output of the ADC/A/D specifies the upper bits of the address number to determine the range of L, and the output of the ADC/A/D specifies the lower bits of the υ address number, and the processor CPU reads L. It is used for comparison or calculation.

FIG. 9 is a flowchart showing the operating status of the processor CPU corresponding to the first invention.J) % initial setting N10
1, and then the paper detection circuit P.
Judgment of ゝゝPaper existence py〃102 by D and ゝDetection timing?? indicated by the timing signal? ”103
If the judgment is Y (YES), ant DO output is possible〃104
In addition to preparations for sending out the power of detection power Do,
By carrying out the ADC operation 105, the amount of transmitted light Dn transmitted through the sheet 2 is sent out from the processing unit PR8,
Is paper 2 the N1th sheet? If it is Y of ``ine'', read from the variable memory IJ RAM! 71 subtraction value generation〃1
0γ is performed, and based on this, a substitution N#108 of Dn-Ln=Mn is performed using the light amount Dn and the subtraction value Ln, and it is determined whether the reference value Mn is within a predetermined range or not according to the output of the changeover switch SW. If a judgment is made and it is within a predetermined range, can one be memorized? ``109 is not Y, the reference value Mn indicated by the result of 1 operation 108 is stored in a predetermined area of the variable memory RAM, 1 storage 110 is performed,
Step 103 and subsequent steps are repeated.

Also, if paper 2 is the second or subsequent sheet, is it the 11th sheet? '1
06 becomes N (No), and the battlefield calculation value is generated in the same way as above.
121 is performed, and at this time, since the light i D n + 1 and the subtraction value Ln+1 are given to the processor CPU, the result of one operation 1122 is an output indicating the reference value Mn+1, and 'Mn≧Dn+1? “123 is N
If so, can you remember it? 〃1 memory 1 after going through 109 Y's
At 110, the content is updated and a new reference value MH+1 is stored in a predetermined area of the variable memory RAM. Prior to this, the scene Dn+1 and the reference value Mn read from the variable memory RAM are In order to be applied to the processor CPU, a comparison of 'Mn''2Dn+1?' 123 is made, and if the result is Y, the detection output 1DO is sent 124 and the process returns to step 103.

Also, is there condolence paper available? //102 and east detection timing?
For N of '103, 'tI'') 0 output not possible''131,
132, the transmission of the detection power DO is prohibited, thereby preventing the transmission of unnecessary signals.

Therefore, by repeating the above operations, υ, paper 2
The optimum reference value Mn is automatically and sequentially determined according to the amount of transmitted light Dn that has passed through the
If it is determined whether or not n+1 indicates a difference between two sheets, the result shown in FIG. 4 is realized.

FIG. 10 is a flowchart showing the operating status of the processor CPU corresponding to the second invention.
1, and then the paper detection circuit P.
Is there a paper by D? “Judgment in 202 and cooperation detection timing indicated by timing signal?” 203
If the judgment is y (ygs), 'Do output is possible〃20
4, preparations for sending out the detection force Do were made, and '
By performing the ADC operation 205, the amount of transmitted light Dn transmitted through the paper 2 is sent out from the processing unit PR8, and whether the paper 2 is the 11th sheet? ``If it is Y in 206, it is determined whether the light amount Dn is within a predetermined range according to the output of the changeover switch SW, and if it is within the predetermined range, can it be stored?〃20γ is Y, and the light amount Dn is a variable memory. The reference value Ln is stored in a predetermined area of +7 RAM and N storage 208 is performed, and a reference value generation 209 is performed by reading out the reference value Ln corresponding to this value from the variable memory RAM, and steps 203 and subsequent steps are repeated.

Also, if paper 2 is the second or later sheet, is it the first sheet? '2
06 is N (No), in this case, the processor C
Since the amount of light Dn+1 is given to the PU, the variable memory lJl
After performing the calculation "221" of Dn-Dn41=S using the light amount Dn read from the predetermined area of 'tAM,
@S>Ln? " 222 is compared, and if the result is Y, perform the detection output "Do Send" and return to step 203.

Regarding the above, if step 222 is N, step 2
Is it possible to move to 07 and memorize 1? 〃D assuming Y of 207
An n+1 Qi memory 208 and a corresponding Qi reference value generation 209 are performed and updated.

Also, there is one paper! +? "202 and" detection timing?
In #203, N, transmission of the detection power DO is prohibited by "0 output disabled" 231 and 232, and unnecessary signals are prevented from being transmitted.

Therefore, by repeating the above operations, υ, paper 2
The optimum reference value is automatically determined one after another according to the amount of transmitted light Dn that has passed through the
If a judgment is made as to whether or not +1 indicates a two-sheet difference, the result shown in FIG. 4 is realized.

However, a low encoder or the like may be used as the detector TD, and the subtraction value or reference value may be stored in the fixed memory R.
The same applies to the OM. Instead of calculation, a table of calculation results may be stored in one of the memories and read out, and the paper detection circuit PD and timing signal generator TSG Function of processor CPU
The present invention can be modified in various ways, such as being equipped with the following.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, an optimal reference value is automatically determined by a simple configuration, and the influence of light transmittance changes of paper and various conditions over time are If the influence of changes is eliminated and the difference between two sheets is always detected reliably, remarkable effects can be obtained in various sheet-fed rotary printing presses.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing the principle of the conventional example, Figures 4 and 5 are diagrams showing the principle of the present invention, Figures 6 and after show examples of the present invention, and Figure 6 is a machine 7 is a block diagram showing the electrical configuration, FIG. 8 is a block diagram showing details of the processing section, FIG. 9 is a processor corresponding to the first invention,
Figure 10 is a Lelow chart showing the operating status of the processor corresponding to the second invention. G: Emitter, LR: Receiver, PH1: Processing section,
CPU --- Processor, ROM ---Fixed memory, RAM...e variable memory, A/I) ---
-ADC (Analog to Digital Converter). Patent applicant Komori Printing Machinery Co., Ltd. Agent Masaki Yamakawa (tji) 2 people) Figure 1-d ('/6) Figure 2/-〆L'/, J Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) The amount of transmitted light transmitted through one sheet of paper and the amount of transmitted light transmitted through two sheets of paper are the intermediate value indicating the value between the two and the amount of transmitted light transmitted through one sheet of paper. an analog-to-digital converter for converting the amount of transmitted light transmitted through the paper into a digital signal; A reference value is obtained by subtracting the subtraction value from the amount of transmitted light that has passed through the paper, and the standard value is compared with the amount of transmitted light that has passed through the current paper.
A two-sheet difference detection device for a sheet-fed rotary printing press, comprising a processor for detecting a sheet difference. (2) The amount of transmitted light transmitted through one sheet of paper and the amount of transmitted light transmitted through two sheets of paper are the same as the intermediate value indicating the value between the amount of transmitted light transmitted through one sheet of paper. a memory that stores a reference value indicating the difference between the calculates the difference between the amount of transmitted light transmitted through the paper and the amount of transmitted light transmitted through the current sheet, and compares the value of the difference with a reference value read from the memory according to the output of the analog-to-digital converter. A two-sheet difference detection device for a sheet-fed rotary printing press, comprising: a processor for detecting a difference between two sheets of paper.