JPS6299149A - Automatic color registering device of printer - Google Patents

Abstract

PURPOSE:To automatically adjust color registering of printed matter by calculating the position of each color registering mark contained in an image after the inclusion of a prearranged part of a pictorial pattern in printed matter into an image. CONSTITUTION:Pressing the pick-up button on the drive side or operating side of an operating panel 3 started is confirmed, and each signal R, G, B and a synchronizing signal are separated by a composite decoder. Of these separated signals, each signal R, G, B is subjected to A/D conversion, then is stored into their respective frame memories. After this procedure, each signal BL, C, M, Y is formed using the signals R, G, B, then is stored into their respective frame memories. The central position of flyback per frame is calculated by digitizing the signals BL, C, M, Y at proper slice level, and is displayed on a CRT screen using a cursor. If an operational button on an operational panel 3 is pressed in this stage, an arithmetic operation on color registering errors is performed, ending the operation after sequential steps such as drive of each motor, judgement of motor position and stop of motors.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an apparatus for determining the misregistration of printed matter and correcting the position of the plate cylinder of a printing press.

[Background technology and its problems]

For example, in the case of an offset printing machine, a printing plate with a pattern formed on it is wrapped around the printing cylinder, the ink stored in the ink tray is transferred to the printing plate via a group of ink rollers, and the ink transferred to the printing plate is transferred to the printing plate. The paper is transferred to a rotating blanket cylinder (blanket cylinder) that presses against the cylinder, and printing is performed by passing the printing paper between the blanket cylinder and the impression cylinder. To perform multicolor printing, the plate cylinder, plunket cylinder, and impression cylinder described above are arranged in units for each color, and the printing paper is passed through each unit one by one.
Complete printing.

By the way, in regular multi-color reoffset printing, if the positions of the printing plates wrapped around the plate cylinder of each printing unit are not in the proper position fi relationship, printing will occur and the L-sided printed matter will be printed in the vertical direction (of the printing paper). (travel direction) A misregistration error occurs in the left-right direction or the twisting direction.

Therefore, in the past, an operator performed a test print, observed the printed material with a magnifying glass, etc., and visually measured the amount of registration error.
The plate cylinder position is adjusted according to this measurement result. This operation is repeated until the registration error disappears.

However, with this method, the operator is required to be skilled because the operator measures the amount of registration error between eyes and adjusts the position of the plate cylinder based on this measurement result. It takes a lot of time and wasted paper because it involves repeated trial and error.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a device that can automatically correct misregistration of printed matter with a simple operation.

[Summary of the invention]

In order to achieve this objective, in the present invention, a predetermined part of the pattern of a printed matter is captured as an image, the position of each color register mark included in the image is calculated, and the misregistration hanging and plate I11 position correction section are cast from this calculated position. The present invention provides a device that automatically corrects the plate IN position based on the results of this calculation.

[Embodiment] The present invention will be described below by way of an embodiment with reference to the accompanying drawings.

FIG. 2 shows the external configuration of an embodiment of the present invention.
Camera 1 magnifies, for example, about 10 times the registration mark, that is, the register mark printed at a predetermined position on print X.
! and gives it to the processing section 2. This processing section 2 receives input from an operation panel 3 outside the camera 1, and provides an output for image display to a CRT 7, and also outputs an output to a motor 5 for driving a register adjustment element of a printing press via a motor drive circuit 4. and input the position data of the register adjustment elements of the printing press from the potentiometer 6.

FIG. 3 shows the configuration of the device shown in FIG. 2 in more detail. Then, as shown in Fig. 3, CI) LJ 1
For the data bus connected to 3, memory ROM, RA
M, an image signal processing circuit including a camera 1j'3 and a CRT7, and a drive (drive side)! Shadow, operation side photography, casting frame,
An operation panel 3 having buttons including four types of reset command buttons, a register correcting element having a motor drive circuit 4 and a motor 5, and a potentiometer 6 for obtaining position data of these register correcting elements are connected. .

The output of camera 1 is given to superimposer 15. The video signal from the video interface 14 and the video signal from the camera 1 are given to the superimport 1115, which forms a signal in which the mountain and gorge image signal is superimposed and is given to the CRT 7 to display the image. The signals are sent to a decoder 8 and separated into horizontal and vertical synchronization signals and R, G, and 83 color signals. If the superimposed signal is only the video from camera 1 (word 43), this video signal is separated.

The separated R, G, 83 color signals are stored in the R, G, B frame memory 9. For example, frame memory 9 is 7
Since the composite decoder 8 has a capacity of 112 <horizontal) x 525 (vertical) bytes, the output of the composite decoder 8 is converted into 8 bits 1~data by the converter 19 and stored in the frame memory 9.

The stored data is R, G, B/C, M, Y.

After being converted into BL, C, M, and Y color values by the BL conversion circuit 11, they are stored in four frame memories 12 of BL, C, M, and Y. R, G, B/C, M, Y, 13
In the 1-conversion circuit 11, C, M, Y, and BL are processed using different methods. That is, first, the complements of the R, G, and B luminance levels are set as the C, M, and Y density levels. Next, in order to extract the 8-color part, the density levels of C, M, and Y are checked for each pixel, and if the density of all three colors, C, M, and Y, is above a certain level, that pixel is classified as B. Assuming that the average density level of each color of C, M, and Y is B +=
Store in the corresponding pixel of frame memory.

In this case, the density level of the corresponding pixel in the C1M and Y frames is zero. However, in the following case, another process is performed.

FIGS. 4(a) and 4(b) explain this other process. If, for example, the above-described process is performed in a state where BL and C overlap, as shown in FIG. 5(a), the image of C (cyan) will be missing as shown in FIG. 4(b). To avoid this, check the brightness level data of the R frame memory, which is the source of the C (cyan) frame, and check that pixels below a certain level (higher density in the C frame) are the overlapped portions of C and BL. Judge, take the complement and convert to concentration,
After multiplying by a certain constant and removing the R portion of l1tlI by BL, it is stored in the C frame.Similarly, perform the operation M1Y
By performing this process on frames as well, four frames, C, M, Y, and BL, are created from the RlG and B frames.

The following image processing is applied to the extracted three frame memory data of each color to determine the center position of the register mark, that is, the register mark.

FIG. 5 shows a register mark called a cross register mark as an example of this register mark, and the center position of this register mark is the intersection of the crosses.

FIGS. 6 and 7 are diagrams illustrating a method for determining this center position. In this case, for example, the dragonfly should be photographed with its sky facing downward.

When the registration mark image photographed in this way is as shown in Figure 6, when the number of pixels determined to have a line in the X and Y directions is added, The cumulative curve shown in is obtained. Note that whether there is a drawing line or not is determined by converting the density of each pixel to 2 (1) at a constant slice level.

When the register mark is tilted by φ degrees with respect to the x and y axes of the CRT, the cumulative curve has a rounded peak. The center of this peak may be determined and used as the xSy coordinates of the center of the register mark, but the center coordinates with higher accuracy can be determined as follows.゛As shown in Figure 7, the cumulative curve shows the sharpest peak when the vertical or horizontal direction of the registration mark coincides with the X or y direction of the CRT, and the peak position in the X and y directions at this time is at the center of the registration mark. Exactly matches the x1y coordinates.

In order to adopt this state, the CPLJ 13 cumulatively adds the number of pixels in the x' and y' directions tilted by 0 degrees with respect to the x1y axes of the CRT, as shown in FIG. 6, and calculates a cumulative curve. Select the tilting angle θ at a sufficiently small constant angle from 0 to ±45°, and
The angle θ at which the peak height of the cumulative curve in the ' direction is the highest is determined to be the inclination angle φ of the dragonfly from the vertical direction.

For the four colors BL, C, M, and Y, the center coordinates of the register mark in the x l y 1 coordinate system are determined from the maximum peak position of the cumulative curve of the tilt angle φ degrees, and this is converted to the CRT coordinate system to obtain the final The position of each color registration mark on CRT coordinates.

Methods other than those described above can also be used to find the center of the register mark. In other words, there is a method of finding the center of gravity of each registration mark from each color registration mark image stored in the Y, M, C, and BL frame memories. In this case, it is necessary to use point-symmetrical register marks so that each register mark is entirely within the field of view of the camera.

The above processing is performed for both the drive side and operation side registration marks of the printing press, and the coordinates of each registration mark on the CRT are determined. A *-shaped cursor is displayed at each registration mark coordinate position on the CRT obtained for confirmation. The cursor image is video I
/ F 14 converts it into a video signal, superimposes it on the image from camera 1 by superimposer 15, and displays it on the CRT.
7 is displayed.

Next, when a "calculation" button (not shown) on the panel 9 is pressed, the amount by which the plate cylinder position should be corrected is determined from the determined coordinates of the register marks and the magnification rate of the image. First, find twist a.

FIGS. 8(a) and 8(b) are explanatory diagrams of this twist suspension calculation, and the registration mark on the operation side on the front side is shown in FIG. 8(a) as J<BL
(e, f), C (Q, h), when the driving side registration marks on the front side are BL (i, j), C (k, I), BL moves to the input side with respect to C ((j-I) - (fh)) xm However, m is twisted by a constant determined by the printing machine and the input registration mark position interval.

In this way, the twist shift @J suspension is determined for each color using a certain color, for example, C (cyan) as a reference, and the twist m of each color is obtained by subtracting the average value of the twist rim from the twist distance of each color. The plate cylinder correction amount in the twisting direction is determined from this twisting amount and the previously known enlargement ratio. The constant m is determined by calculating the registration mark interval from the registration mark positions on the operating side and the driving side that have been input using the numeric keys.

Similarly to twisting, the amount of movement in the vertical and horizontal directions in order to overlap these registration marks can be determined by simple calculations.

The method of calculating this amount of movement is as follows: - As an example, the movement 17[ is calculated by aligning the vertical, horizontal, and twisting directions of all registration marks to the average position, but excluding the registration marks that are extremely deviated. An average position may also be determined. It may also be possible to provide an instruction to match a register mark of a specific color or a specific location. From this movement amount and magnification rate, the plate cylinder position correction time in the vertical, horizontal, and twisting directions can be determined.

The plate cylinder position adjustment m obtained in this manner is sent to the motor drive circuit 4, which drives the vertical, horizontal, and twist motors 5 for each color. The position of the plate 11 is detected by the potentiometer 6 and provided to the CPU 13, and the CPU 13 controls the plate cylinder to stop at an appropriate position.

FIG. 1 shows the operation of the apparatus of the present invention.

When this device starts, confirm that the shooting button on the drive side or operation side of the operation panel 3 (Fig. 3) has been pressed (
SL). Then, in step S2, the R, G, B signals and the synchronization signal are divided into 1111 parts by the composite I decoder.
1- Do. Among these separated signals, each R and GSB signal is
/D conversion (S3), and each is stored in a frame memory (S4). R stored in this frame memory,
The G and B signals are used to form the C, M, and Y signals (S5), and each is stored in the frame memory (S5).
6). By binarizing these 8m, 01M, and Y signals at an appropriate slice level (S7), the I
- Calculate the center position of the mark (S8).

The center position of this single registration mark is displayed on the CR1 screen with a cursor (S9).

At this stage, when the calculation button on the operation panel 3 (Fig. 3) is pressed (S10), the register error foot calculation is performed (S11),
Thereafter, in accordance with steps 814 to 816, each motor drive (814), motor position determination 11!1 (815), and motor stop 7' (816) are sequentially performed, and the process ends.

On the other hand, if the calculation button is not pressed, either the relet or photographing button is pressed J3 to proceed to the next step.

First, in the case of the reset 1~ button, the process moves to step 813 to clear the calculation contents (813), and returns to step S1.

If the photographing button is pressed, the process returns to step S1 without clearing the calculation contents, and input for photographing the registration mark on the opposite side is performed.

FIGS. 9(a) and 9(b) show other examples of the register marks handled in the present invention. FIG. , M, and Y. Since the vertical register generally deviates by only about ±1111, the order of 8L, CSM, and Y does not change even if the register is deviated.

FIG. 10 shows a method for determining the vertical coordinates using the image shown in FIG. 9. To do this, convert the image into two values at an appropriate slice level, import it into one frame memory, and use the same procedure as above to find the inclination angle φ of the register mark.
Next, we will show how to find the peak corresponding to each mark from the cumulative curve in the X' force direction and obtain the coordinates in the vertical direction. The cumulative curve is determined, and the left and right coordinates are determined from the X' coordinate value indicating its peak.The subsequent processing is exactly the same as in the previous embodiment.

According to the method described using FIGS. 9 to 11, the configuration of the apparatus d and the processing work can be greatly simplified.

〔Effect of the invention〕

The present invention, as described above, is capable of printing a predetermined portion of a printed matter in one il.
The position of the register mark included in the image is extracted using Iv, which is taken in as a j image, and the registration distance and plate cylinder position correction period are calculated from this calculated position, and the plate cylinder position d is automatically corrected based on this calculation result. Due to the unskilled work & handling
It is possible to provide a device that can accurately register.

40 drawing f! ! 1 is a flowchart showing an example of the operation of the device of the present invention, FIG. 2 is a diagram showing an external appearance of an example of the device according to the present invention, and FIG. 3 is a diagram showing a more detailed configuration of the device. Figure 4(a), (
b) is an explanatory diagram of another processing content performed by the same device, No. 5
The figure shows an example of a register mark that serves as a reference for control operations by the device, Figures 6 and 7 are explanatory diagrams of a method for determining the center position of the mark, and Figures 8 (a) and (b) 9 is an explanatory diagram showing another example of the register mark, and FIGS. 10 and 11 are explanatory diagrams of a method for determining the mark center position using the register mark in FIG. 9. It is.

DESCRIPTION OF SYMBOLS 1...Camera, 2...Processing part, 3...Operation panel, 4...Motor drive circuit, 5...Motor.

For applicant's agent Sato Fuji Copper figure 2: Figure 3 (b) Figure 4 Figure 5 (a) (b) -Earth one( →Heaven (a) (b) Figure 9 Figure 1I procedure? rli main gate 7th month, 1986

Claims (1)

[Scope of Claims] Data importing means for capturing a predetermined portion of a pattern of a printed matter as an image and storing it as data for each color; means for recognizing the position of a predetermined element in each color data; and each color obtained by the recognition means. means for calculating the amount of positional deviation between colors based on the position of a predetermined element for each color, the amount by which the printing press plate cylinder position should be corrected according to this positional deviation amount; An automatic registration device for a printing press, comprising means for automatically correcting the position of the printing cylinder of the printing press accordingly.