JPH0516348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting registration errors occurring in rotary printing presses.

[Conventional technology]

In a rotary printing press that has multiple plate cylinders, printing is performed sequentially on a long paper such as roll paper using the plates of each plate cylinder, and if the printing position of each plate on the long paper is different, the pattern may be different. Because discrepancies occur, in order to automatically correct the registration error depending on the printing position of each plate and control the image patterns of each plate to match,
JP-A-58-14751 filed separately by the applicant;
Various automatic register adjustment devices are disclosed in Japanese Patent Application Laid-Open No. 58-14752 and the like.

[Problem that the invention seeks to solve]

However, conventional methods do not take into account the expansion and contraction of long paper, and when long paper expands and contracts depending on various printing conditions, the detection status of registration errors and the adjustment status based on this become inaccurate. will occur.

[Means for solving problems]

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

That is, two reference marks are printed on a long sheet of paper using the same printing plate at regular intervals in the feeding direction of the long sheet of paper, and at least two reference marks are printed at a predetermined interval in the feeding direction of the long sheet of paper using different printing plates. Register marks are printed, each of these marks is detected as an electrical signal by a detector facing each of these marks, and based on this electrical signal, the interval between each reference mark and the interval between each register mark is determined individually. The amount of registration error between different plates is detected by calculation based on the interval ratio and each interval of each mark.

[Effect]

Therefore, during calculation, the spacing between the reference marks and the spacing between the register marks are calculated individually, and the spacing ratio is calculated, and the expansion/contraction situation of the long paper included in this is removed to ensure accurate registration errors. amount can be detected.

[Example] Hereinafter, details of the present invention will be explained with reference to figures showing examples.

Fig. 1A is a diagram showing the printing status of each mark, and Fig. 1B is a diagram showing the waveform of the detection signal. The first and second reference marks 2a, 2b are made by the same plate at regular intervals in the direction.
At the same time, the first register marks 3a and 3b are printed on slightly different parts with a predetermined interval D using mutually different plates,
In this example, the reference marks 2a and 2b are both printed in the same color, and the register marks 3a and 3b are printed in different colors.The reference marks 2a and 2b and the register mark 3a are printed by the same plate, and the register mark 3b is printed by a different plate. .

Each of these marks is detected as an electrical signal by a photoelectric detector 5 of a reflected light type or a transmitted light type fixed on the scanning line 4 facing each mark. Since the detection is performed on the long paper 1, the pulse-like signal shown in B is detected on the long paper 1.
obtained according to the transfer of

Here, k is the expansion/contraction rate of the long paper, Δd is the amount of registration error between each printing plate for printing each register mark 3a, 3b, and T is the time between each pulse corresponding to each reference mark 2a, 2b. , each register mark 3
Let t be the time between each pulse corresponding to a, 3b,
If the transport speed of the long paper 1 is constant, k is actually included in the actual interval dor between the reference marks 2a and 2b,
Since the actual distance Dr between the register marks 3a and 3b includes k and Δd, the following equation holds true.

t/T=Dr/dor=k(D+Δd)/k・do=D+Δd/d
o…(1) If Δd is found from equation (1), the following equation is obtained.

Δd=t/Tdo−D (2) Therefore, the amount of misregistration Δd can be detected by calculating the equation (2) based on the ratio of each time T and t and the known intervals do and D. In addition, when calculating the time ratio, the expansion/contraction rate k is removed by elimination as shown in equation (1), and an accurate Δd can be obtained without the influence of this.

FIG. 2 is a block diagram of an electric circuit for automatic register adjustment based on the above principle, in which the electric signal from the detector 5 described above is shaped into a pulse signal by the waveform shaping circuit 20, and the electric signal is shaped into a pulse signal by the rotation of the printing press. A gate pulse generation circuit 21 generates a gate pulse in accordance with the
In response to the output, only the pulse signal is extracted in the gate circuit 22, and a reset signal is sent to the counter at the same time as the gate pulse rises. Next, the control circuit 23 sends out a latch signal in response to the rise and fall of this pulse signal.

Further, the output of a clock pulse generation circuit 24 that generates clock pulses with a sufficiently high frequency compared to times T and t is given to a counter 25, and the counter 25 generates clock pulses in response to a reset signal from the gate pulse generation circuit 21. Counting is started, and the clock pulses from the rise to the fall of the pulse signal are determined by the latch signal from the control circuit 23 as count values, each of which is sequentially held by the latch circuit 26, and then processed by the microprocessor, memory, etc. Here, the number of clock pulses corresponding to the times T and t is calculated, and then the calculation of equation (2) is performed, and the calculation unit 27 sends out a control output according to Δd. (hereinafter referred to as I/F) 28
a, 28b to digital-to-analog converters (hereinafter referred to as DACs) 29a, 29b, which send analog control signals to the respective plate cylinders on which each plate is attached via drive circuits 30a, 30b. The vertical register adjustment motors 31a and 31b are driven.

Therefore, the motor 31a corresponding to the register mark 3a in FIG. 1A and the motor 31b corresponding to the register mark 3b respond, and register adjustment is performed.

However, each plate cylinder is equipped with a potentiometer 41a, which detects the vertical position corresponding to the rotation reference angle.
41b are respectively provided, and a multiplexer 42 alternately selects these detection powers at high speed.
Analog-digital converter (hereinafter referred to as ADC) 4
3, and each detected force converted into a digital signal is sent to the computing unit 2 via I/F44.
7, the calculator 27 checks the registered position of each plate cylinder in accordance with this, and when the desired position is reached,
Alternatively, when the adjustment limit position is reached, the driving of the motors 31a and 31b is stopped.

FIG. 3 shows the printing situation of each mark showing another embodiment. In A, each register mark 3a is printed between the first and second reference marks 2a, 2b.
3b is printed in the same manner as in FIG. In addition to being used as reference marks, each register mark 3a, 3b is printed in the same manner as in FIG.

Therefore, if the detection powers of these detectors 5 are processed according to their rankings, or if the leading edge 3c and the trailing edge 3d in FIG. Get results.

However, the shape of each mark can be arbitrarily selected according to the conditions, and the shape of each mark can be arbitrarily selected according to the conditions.
The number of plates may be determined according to the number of plate cylinders, and in some cases, they may be of the same color.

Further, the configuration shown in FIG. 2 may be determined depending on the situation, and if the drive circuits 30a and 30b respond to digital signals, the DACs 29a and 2
9b can be omitted, and the potentiometer 41
Various modifications are possible, such as the ADC 43 can be omitted by using devices that send out digital signals in place of a and 41b.

Furthermore, it goes without saying that by detecting the length across each register mark, the amount of misregistration in the left and right direction can be detected in a similar manner.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the influence of expansion and contraction of long paper is eliminated, and registration errors between plate cylinders can be accurately detected, so that registration errors in various rotary printing presses having multiple plate cylinders can be detected accurately. Significant effects are obtained in detection and adjustment.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1A is a diagram showing the printing status of each mark, FIG. 1B is a diagram showing the detection signal of each mark, FIG. FIG. 3 is a diagram showing the printing status of each mark according to another embodiment. 1...Long paper, 2, 2a, 2b...Reference mark, 3a, 3b...Register mark, 4...Scanning line, 5...Detector, 24...Clock pulse generation circuit, 25...Counter, 27 ...Arithmetic unit, 31
a, 31b...motor, do...fixed interval, D...
...Predetermined interval, T, t...time.

Claims (1)

[Claims] 1. Print two reference marks on a long sheet of paper at regular intervals in the feeding direction of the long sheet of paper using the same printing plate, and print at least two register marks at predetermined intervals in the feeding direction using different printing plates. and detecting each mark as an electrical signal by a detector facing each mark,
Based on the electric signal, the intervals between the reference marks and the intervals between the register marks are determined individually, and the amount of registration error between the different plates is detected by calculation based on the interval ratios and the constant intervals. A registration error detection method featuring the following.