JPH0288242A - Register controller for multi-color printing machine - Google Patents

Abstract

PURPOSE:To enable color register to be performed highly accurately without using a specific register mark by a method wherein R, G, R image signals outputted from a color camera which inputs a cross register image to be printed together with a pattern are stored, and specific calculation is performed to generate a register control signal based on the result. CONSTITUTION:A free guide roller 40 is provided to a part of a web path part 34, and a strobe light for inputting a cross register of continuous paper 10 wound around a free roller 40 and a color camera 50 which outputs an input image by decomposing its color into R, G, B image signals are established. A reflecting beam sensor 52 is attached just before the color camera 50 in the progressive direction of the continuous paper, and a start mark 62 of a pattern 60 to be printed continuously on the continuous paper 10 is read. Besides, the image signal from the color camera 50 and a start pulse from the reflecting beam sensor 52 are inputted to a register control circuit dd, and a register shear amount between respective colors is calculated with the register control circuit dd. Then, registering is completed by driving plate cylinder registering motors 21a, 21b, 21c, 21d for plate cylinder phase registering of respective printing units by required contents correspondingly thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a multicolor printing press, and particularly to a register control device for a multicolor printing press for automatically adjusting the register of each color of a printed matter being printed.

<Prior art> Conventionally, the registration of each color in a multi-color printing press has been done manually, with a person checking the amount of misregistration of each color by making a test print, and then adjusting the color registration using the printing press's registration adjustment device. was.

Normal multicolor printed matter is made by printing four process colors (ink 2, indigo, red, and yellow) on a single sheet of printing paper, and if the positional relationship of each color is correct, there will be no problem. If the positional relationship is out of order (called misregistration or misregistration), the print quality will deteriorate significantly, and the tolerance is ±5710
Since strict precision of 0-4 or less is required, registration work places a heavy workload on printing press operators.

For this reason, various companies have recently developed and announced devices for automatically adjusting color registers in multicolor printing presses. As an example, the registration adjustment device disclosed in ``Japanese Patent Application Laid-Open No. 60129261'' attempts to adjust color registration before printing starts by placing special marks on the printing plates and adjusting the positional relationship of the printing plates. It is.

<Problems to be Solved by the Invention> However, in this type of apparatus, it takes time and effort to put marks on the plate material. Furthermore, even if the positional relationship of the printing plates is correct, there is a problem in that positive registration cannot be achieved due to the expansion and contraction of the printing paper, so this method is not used much in practice. On the other hand, there are devices that use special marks printed in various colors on printing paper other than those mentioned above to perform registration by selling optical sensors, but even with this type of device, it takes a lot of effort to add special marks. However, major problems remain, such as waste of paper and waste of paper.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to provide a configuration that allows highly accurate color registration without using a special registration tool. An object of the present invention is to provide a register control device for a multicolor printing press that is simple and suitable for the multicolor printing press.

<Means for Solving the Problems> In order to achieve the above object, the present invention detects the misregistration amount and misregistration correction direction of other colors with respect to the reference color for each color, and adjusts the misregistration of each color based on the detection results. Move the plate cylinder of 5? A register control layer device for a multicolor printing press that matches the register of gold by eliminating the register misregistration with the J color is equipped with a color camera that inputs the image of the cross register mark printed with the pattern, and an R output from the color camera. , G, B, and t of the following (a) to (d).
The apparatus includes a calculation means having an arithmetic function means, and means for generating a register control signal based on the calculation result from the calculation means.

(a) Functional means for creating level data of a cross register mark image for each color from the R, G, and B image signals stored in the storage means.

(bl + m Functional means for calculating the center coordinate position of the cross register mark from the level data of the cross register mark image for each color.

(c1 Functional means that calculates the difference between the center coordinate position of the cross-shaped registration mark and the reference coordinate position, and calculates the misregistration position and misregistration direction of each color from the calculated difference when the difference is greater than a predetermined certain amount.

(d) When the difference between the center coordinate position of the cross registration mark and the reference coordinate position is less than a predetermined amount, the width and coordinates of the cross registration mark line are calculated to correct the misregistration of each color and the direction of misregistration. Functional means to calculate.

<Operation> Therefore, according to the present invention, in a multicolor printing press, the registration of each color can be automatically performed using the cross register marks conventionally used in plate making without adding special registration marks. becomes possible.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the overall configuration of a register control device for a multicolor printing press according to the present invention. Although an embodiment adapted to an offset rotary printing press will be described here, there is no problem even if the target printing press is an offset sheet-fed printing press.

In FIG. 1, a roll of paper lO is supplied to printing units 20a to 20d, and each unit prints black, indigo, red,
Patterns of each color of yellow are printed in sequence. For example, the black unit 20a is composed of a front blanket cylinder 22a, a front blanket cylinder 24a, a back blanket cylinder 26a, and a black plate cylinder 28a. is transferred under pressure and printing is performed. This also applies to the other units 20b, 20c, and 20d. Here, only the registration on the front side of the printing paper will be explained, but since it can be performed in the same manner on the back side, the explanation will be omitted. Further, in order to register each color, the registration is adjusted by adjusting the phase of the plate cylinder 22 in the direction of rotation and the direction of its rotation axis. As disclosed in
1a, 21b, 21c, and 21d, and since it is well known, a detailed explanation thereof will be omitted here.

The web 1O that has been printed in each color by each printing unit is dried with hot air in a dryer 30, cooled in a cooling section 32, and discharged through a web path section 34 and a folding machine section 36. Here, a part of the web path portion 34 includes a free guide roller 40 (hereinafter referred to as a free roller).
is provided with a strobe 46 for inputting the cross register mark of the web IO wound around the free roller 40;
A color television camera is provided as a color camera 50 that separates an input image into R, G, and B image signals and outputs the signals. Note that the color camera 50 is not limited to a color television camera (a color line sensor camera may also be used). This is for reading a start position 62 provided at the printing start position of the patterns 60 that are successively printed on the web 10.

FIG. 2 is a schematic diagram showing the relationship between a pattern (including a cross mark) and a start mark. Here, if the start position of the pattern can be determined to some extent from the rotation of the plate cylinder 22, etc., the start mark 62 and the reflective beam sensor 52 are unnecessary. These are merely for controlling the timing when the color camera 50 inputs the cross mark 64 within the picture.

On the other hand, the image signal from the color camera 50 and the start pulse from the reflective beam sensor 52 are sent to the register control circuit 44.
The register control circuit 44 calculates the amount of register misregistration between each color, and accordingly, the plate cylinder phase alignment morphs 21 a and 21 b of each printing unit are adjusted as necessary.
, 21c, and 21d to complete registration. Here, registration may be controlled for all consecutive printed matter, or may be controlled once for every few sheets.

FIG. 3 is a block diagram showing an example of the configuration of the register control circuit 44. As shown in FIG. In this embodiment, a case will be described in which a color television camera is used as the color camera 50.

In FIG. 3, the color camera 50 converts R, G, and B video (image) signals V, V, and VB into binarization circuits 101 and 101, respectively. It is output to 102.103.

The binarization circuit +01.102.103 inputs R, G, B video signals V, V, V at a threshold level (direct) set in advance.

is binarized and output as a binarized signal B,,B,B,. That is, in the R, G, and B video signals, large output levels are obtained for indigo, red, and yellow, which are complementary colors, respectively, and large output levels are obtained for black in both the RSG and B video signals. By setting an appropriate threshold level using this relationship, the binarization circuit 10
From 1, a binary signal B representing an image of an indigo and black dragonfly;
are output, and the binarization circuits 102 and 103 output binarized signals B c B m representing red and black register mark images and yellow ink register mark images, respectively. This binary signal B* Bc Be is R, C, , B
Image memory 111. Input to 112, 113, RlG, 8 image memory 111. At 112 and 113, binary signals B, BG B, are written in accordance with the memory control signal MC from the memory control circuit 120.

Here, the timing control circuit 110 controls the capture of the image including the register marks on the web from the color camera 50 . That is, when the beam sensor 52 reads the start mark on the web 10, a detection signal DT is output,
When this detection signal DT is input, the timing control circuit 110 outputs a light emission signal S to the strobe 46 to cause the strobe 46 to emit light, and causes the color camera 50 to capture the image of the register mark on the web 10.

Further, the timing control circuit 110 outputs the image input signal I to the data calculation processing section 130 when the detection signal DT is input, and the data calculation processing section 130 at this time outputs the image input signal I to the memory control circuit 1.
By the control signal CT output to 20, R,,G,8
Image memory 111.112.113 Color camera 5
A binary image of the register mark is written from 0 through the binarization circuits 101, 102, and 103. Thereafter, in the data calculation processing section 130, R, G, 8 image memories itt, 112 .
Data DI from 113 and BK image memory 114
By performing processing such as calculation using DG DI Dam, the amount of correction of the register is determined.

Here, data is read from the image memory and data is written to the image memory from the memory control circuit 120 to the RSG, B, BK image memories 111. 112.11
The instruction to read or write to the memory control circuit 120 is performed by a control signal CT from the data arithmetic processing section 130. Naori K image memory 114 has RS G
, 8 image memories 111, 112, and 113. Binary images of black registration marks obtained by arithmetic processing are stored therein.

Next, the register control operation by the data arithmetic processing unit 130 of the register control circuit 44 will be explained using the flow diagram of FIG.

The register control circuit 44 controls the roll paper lO from the color camera 50.
After importing the above dragonfly image, RSG,
8 image memories 111, 112, and 113 respectively store images containing indigo, red, and yellow registration marks as well as ink registration marks. The data calculation processing unit 130 performs step S
In step 1, a binary image in which black, indigo, red, and yellow register marks are separated is calculated from the data in each image memory.

゛Here, the separation of the register marks for black, indigo, red, and yellow into binary images is performed using the black After separating the binary image of the register mark, the data is further calculated by calculating the data of the binary image of the black register mark and the data of R, G, and 8 images.
Since it is disclosed in No. 8268 °゛ etc. and is publicly known,
A detailed explanation thereof will be omitted here.

After completing the separation of the registration marks of each color into one image, the reference coordinates that serve as the reference for registration are determined in step S2.The reference coordinates are the target positions for aligning the registration marks of each color. Here, the center coordinates of the register marks in the image are used as a guide for registration, and the reference coordinates are determined using the center coordinates of the black register marks.

The method for finding the center coordinates from the binary image data of the register mark is as follows:
Here, using the method disclosed in "Japanese Patent Application No. 6318268", the sum of the level data of each line in the X direction and Y direction of the binary image data is calculated, and the coordinates of the line whose sum is above a certain value are calculated. The center coordinates can be found by calculation.

After determining the reference coordinates, in step s3, in order to correct the register, the center coordinates of the registration mark of the target color to be corrected are determined. The method for determining the center coordinates may be the same as the method used in step s2. Here, indigo, red, and yellow dragonflies overlap,
Also, if an ink dragonfly and a dragonfly of another color overlap or overlap,
In binary images of register marks of colors other than black, overlapping parts may be missing and center coordinates may not be determined. In step s4, it is checked whether the center coordinates of the register marks of the target color were obtained in step S3. If the coordinates were not obtained, the process moves to step S8, and if the coordinates were obtained, the process moves to step s5. .

In step S5, the difference between the center coordinates of the register mark of the target color obtained in step S3 and the reference coordinates is obtained as ΔX and ΔY for the X and Y coordinates, respectively. Next, in step S6, it is determined whether the coordinate difference ΔX and ΔY is larger than a predetermined setting value D1, and if ΔX or ΔY is larger than DI (ΔX<-DI, Dl
i<ΔY), in step S7, if it is smaller than DI (
-Di≦ΔxSDI, -D1≦ΔY≦D1), the process moves to step S8. When the registration of each color is almost the same, the registration marks will overlap, and as mentioned above, in the binary image of registration marks other than black, the overlapping part will be missing, and from the difference between the center coordinates of the registration marks and the reference coordinates, Registration becomes impossible. Therefore, if the coordinate difference ΔX1ΔY is smaller than the set value Dl, processing for more precise registration is performed. The thickness of registration marks on normal printed matter is approximately 0.1 mm, so if the difference in coordinates is less than 0.1 mm, it can be determined that the registration marks overlap, and the set value Dl is the value corresponding to 0.1 mm +. do.

If the coordinate difference ΔX, ΔY is larger than the set value D1, in step S7, the value of ΔX1ΔY is converted into a correction amount for the phasing motor of the printing press, and the correction amount is sent from the register control circuit to the phasing motor of the printing press. The register correction is output.

On the other hand, if the center coordinates of the register marks cannot be found due to overlapping of the register marks, and if the difference between the center coordinates of the register marks of the target color and the reference coordinates is less than the set value DI,
In step S8, the thickness of the line of the register mark, W8, is measured from the binary image of the register mark. The method for measuring the thickness of the line of the register mark uses the result of the summation calculation of line level data in the X direction and Y direction in the binary image, which is performed when finding the center position of the register mark. The method for measuring the thickness of the register mark line will be explained in detail with reference to FIGS. 5, 6, 7, and 8.

As an example, assume that ink and indigo dragonfly overlap, and the center of the dragonfly is in the state shown in FIG. 5(a). The binary image of the black dragonfly separated for each color from this image is as shown in FIG. 5 Φ), and the binary image of the blue dragonfly is as shown in FIG. 5(c). As described above, in the binary image of the indigo dragonfly, the portion that overlaps with the black dragonfly is missing. In this example,
Assuming that the coordinate relationships in the images of the black and blue dragonflies are as shown in Figure 7, the summation result of the level data of the lines in the Y direction and the X direction for both images is the 7th The results are as shown in Figure 8.The total sum of lines where registration marks exist is large, so in order to detect the presence or absence of registration marks, an appropriate threshold value, LTH, is determined in advance, and whether the total sum of lines is larger than LTH is determined in advance. By comparing, it is possible to extract the line where the registration mark is present.

At this time, the number of extracted lines becomes the thickness of the registration mark in the binary image. The widths of the vertical lines and horizontal lines of the indigo dragonfly measured from the binary image of the indigo dragonfly are W in FIG. 7(b) and WV in FIG. 8(b).

When the registration is correct, the registration marks of each color overlap completely, so the thickness of the registration mark line WK and Wy measured from the binary image of the registration mark corresponds to the amount of misregistration, and the amount of registration correction can be determined. It turns out. Here, in the registration control device, since the camera itself that inputs the image of the cross register mark has a resolution limit and blurred images, the limit of 1 h degree for measuring the thickness of the register mark line in step S8 is broken. There is. If the thickness of the measured line of the register mark is less than the accuracy, it can be determined that the registration is almost correct, and in step S9, the determination of whether the registration is correct is made by setting the register mark corresponding to the measurement accuracy of the registration control device. This is done using the value D2. If the size W, l WV of the register mark line is larger than the set value D2, in step SIO, the register control circuit outputs a register correction output to the phasing motor of the printing press. At this time,
The amount of registration correction is calculated from the thickness WX, W of the registration mark line, and the registration correction direction is calculated from the magnitude relationship between the coordinates of the line extracted in step S8 where the registration mark exists and the reference coordinates. Also, the thickness of the registration mark line W, Wv
If it is less than the set value D2, it is determined that the register is correct at the step Sll, and no output for register correction is made from the register control circuit.

One register control process for one color is performed in Sll from step S3 above, and after the same process is performed for each color (step 512), a new registration mark image is input, and the registration mark image for each color is In step S13), the same register control operation is repeated for each binary image.

As described above, the center position coordinates of each color registration mark and the thickness of the registration mark line are obtained, and when the amount of misregistration is greater than a certain amount, the difference between the reference coordinates and the center position coordinates of the registration mark is used to correct the registration. When there is an amount of misregistration under enuresis, the thickness of the register mark line is further used to correct the misregistration, thereby controlling the color misregistration with high precision.

In the above embodiment, as shown in FIG. 2, the color registration was controlled only by the cross register mark 64a immediately after the start mark, but the two cross register marks 64a in the flow direction of the web lO
By performing similar processing on 64b and 64b, it is also possible to correct the twist register of the plate.

Furthermore, it is also possible to use a color line camera instead of a color television camera, and in this case, a strobe is replaced with a normal illumination light source, and a rotary encoder is attached to the free roller 40 to determine the timing of image capture. That's fine.

Furthermore, the series of processes 5l-S13 in FIG. 4 by the data calculation processing unit 130 in FIG. It can be realized by a CPU or by other circuit configurations.

<Effects of the Invention> As explained above, according to the present invention, it is possible to adjust color registration with high precision even for minute misregistrations without using new special registration marks. , it is possible to provide a register control device for a multicolor printing press that has a simple configuration and is most suitable for a multicolor printing press.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of a register control device for a multicolor printing press according to the present invention, FIG. 2 is a schematic diagram showing the relationship between a start mark and a cross register mark, and FIG. 3 is a register diagram in the same embodiment. FIG. 4 is a block diagram showing an example of a control circuit, and FIG. 4 is a flow diagram for explaining the register control processing of the register control circuit in FIG. 3. Figure 5 Cal (bl (c) is a schematic diagram showing how to separate the binary images of each color of registration marks from overlapping two-color registration marks, and Figure 6 is a schematic diagram showing the coordinates in the overlapping two-color registration mark images. , Fig. 7 (al et al.) is a schematic diagram showing how the sum of line data in the Y direction of each color is calculated for the image in Fig. 6, and Fig. 8 (a) and (b) are It is a schematic diagram showing how the sum of line data in the X direction of each color is calculated for the image. 44... Registration control circuit 46... Strobe 50
...Color camera 52...Beam sensor 10
0...Timing control circuit Ill ~114...Image memory +20...Memory control circuit +30...Data calculation processing unit Patent application Person Toppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 2 trl ゝ\- Xto26fi- Fig. 6 Fig. 8 (a) Fig. 8 (1))

Claims (2)

[Claims] (1) Detect the misregistration amount and misregistration correction direction of other colors with respect to the standard color for each color, and move the plate cylinder of each color of the printing press based on the detection results to eliminate the misregistration with the standard color. In this register control device for a multicolor printing press, the register of all colors is made to match, a color camera inputting an image of a cross register mark to be printed together with a pattern, and R, G, A storage means for storing the image signal B, a calculation means having the following functional means (a) to (d), and a means for generating an register control signal based on the calculation result from the calculation means. A register control device for a multicolor printing press, characterized by comprising: (a) Functional means for creating level data of a cross register mark image for each color from the R, G, and B image signals stored in the storage means. (b) Functional means for calculating the center coordinate position of the cross register mark from the level data of the cross register mark image for each color. (c) Functional means that calculates the difference between the center coordinate position of the cross registration mark and the reference coordinate position, and calculates the misregistration amount and misregistration direction of each color from the difference obtained when the difference is larger than a predetermined fixed amount. . (d) If the difference between the center coordinate position of the cross registration mark and the reference coordinate position is less than a predetermined amount, the amount of misregistration and misregistration of each color can be determined by calculating the width and coordinates of the cross registration mark line. Functional means for calculating direction. (2) In the functional means for calculating the center coordinate position of the cross register mark and the line width of the cross register mark in the register control device for a multicolor printing press, the cross register mark image for each color is calculated for each line in the vertical and horizontal directions. Multicolor printing characterized by calculating the sum of level data, and calculating the center coordinate position of the cross register mark and the width of the line of the cross register mark from the position and number of lines whose sum is larger than a predetermined constant value. Machine register control device.