JPH01192559A - Register controller for multicolored printer - Google Patents

Abstract

PURPOSE:To enable color register to be performed high precisely, by a method wherein a distance of out of register another color to a reference color and a correction direction of out of register is detected on each color, and a plate cylinder of each color is moved on the basis of this detection result. CONSTITUTION:A data operation processing part 113 performs processes of operation or the like by using data DR, DG, DB, DBK from R, G, B image memories 111, 112, 113, and a BK image memory 114, and outputs a register correction distance and a correction direction to a register adjuster of a printer. A data operation processing part 130 operates the total sum of a pixel data in a line on each line in X and Y directions of a binary image of the register mark. The total sum of lines wherein the register mark exists is larger than the total sum of other lines; an appropriate threshold value Lth is established to the total sum thereof. In order to obtain a X-coordinate position of a central coordinate position, the X-coordinate position of a line of which the line total sum in the Y direction exceeds the threshold value Lth is extracted, and further, the Y coordinate is obtained in the same way to operate the distance and direction of out of register.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multicolor printing press, and more 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.

[Conventional technology]

Conventionally, the registration of each color in a multicolor printing press has been performed manually, with a person checking the amount of misregistration of each color by making a trial print, and then adjusting the color registration using the printing press's registration adjustment device.

Normal multicolor prints have four process colors (ink, indigo, red, yellow)
If the positional relationship of each color is correct, there will be no problem, but if the positional relationship is incorrect (called misregistration or misregistration), the print quality will deteriorate significantly. The tolerance is ±5/1
Since strict accuracy of 0.000 am or less is required, registration work has been a heavy workload for 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. 129261/1980'' attempts to adjust the color registration before printing starts by placing special marks on the printing plates and adjusting the positional relationship of the printing plates. It is something to do.

[Problem to be solved by the invention]

However, in this type of apparatus, it is time-consuming to place marks on the plate material. Furthermore, even if the positional relationship of the printing plates matches, there is a problem in that accurate registration cannot be achieved due to the expansion and contraction of the printing paper, so it is not used much in practice. On the other hand, in addition to the above, there are devices that use optical sensors to read special marks printed in each color on printing paper to perform registration, but even with this type of device, it takes time and effort to add special marks and wastes paper. Major problems remain.

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

[Means to solve the problem]

In order to achieve the above object, the present invention detects the amount of misregistration and misregistration correction direction of other colors with respect to the reference color for each color, and moves the plate cylinder of each color based on the detection results to A registration control device for a multicolor printing press that matches the registration of all colors by eliminating misregistration with the color camera is equipped with a color camera that inputs the image of the cross register mark printed with the pattern, and the R, G output from the color camera. , B
storage means for storing the image signals of; and the following (al to (e)
The apparatus includes a calculating means having l functional means, and means for generating a register control signal based on the calculation result from the calculating means.

(Functional means for reading out R, G, and B image signals from the al storage means. (Functional means for creating level data of a cross register mark image for each color from the R, G, and B image signals. (C)
Functional means that calculates the sum of level data for each line in the vertical and horizontal directions of the cross register mark image for each color. ((1
) Functional means for calculating the center coordinate position of the cross register mark from the coordinate position of the line for which the sum of level data is greater than the threshold value. (e) Functional means for calculating the amount of misregistration and direction of misregistration for each color by calculating the difference between the center coordinate position of the cross register mark and the reference coordinate position.

[For production]

Therefore, according to the present invention, in a multicolor printing press, it is possible to automatically register each color using the cross mark and cross mark conventionally used in plate making without adding special registration marks. It becomes possible.

〔Example〕

An embodiment 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-shaped web 10 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 layer blanket cylinder 26a, and a 7i 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. In addition, 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. A phasing motor 2 provided on each plate cylinder as disclosed in
1a, 21b.

21C and 21d are performed automatically and are well known, so detailed explanation thereof will be omitted here.

The web 10 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 bath section 34 and a folding machine section 36. Here, a free guide roller 40 (hereinafter referred to as a free roller) is provided in a part of the web path section 34, and a strobe 46 is used to input the cross mark on the web 10 wound around the free roller 40. , a color television camera is provided as a color camera 50 that color-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 the start mark 62 provided at the printing start position of the pattern 60 that is 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 starting position of the pattern can be determined to some extent from the rotation of the plate cylinder 22, etc., then
The start mark 62 and reflective beam sensor 52 become 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 amount of misregistration between each color is calculated by the register control circuit 44, and the plate cylinder phasing motors 21a, 21b, 21c of each printing unit are adjusted accordingly as necessary.
, 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 is R, G.

B video (image) signal■Eh,■. , ■, each 2
It is output to value conversion circuits 101, 102, and 103. The binarization circuits 101, 102, and 103 binarize the input R, G, and B video signals V+t, VG, and Va according to a preset threshold level, and obtain a binarization symbol. Output as BR2Bc, By. That is, R,G.

In the B video signal, high output levels are obtained for indigo, red, and yellow, which are complementary colors, and for black, R,
Large outputs can be obtained for both G and B video signals. By using this relationship to set an appropriate threshold level, the binarization circuit 101 outputs the binarization symbol BR representing the image of the indigo and black dragonfly.
From 02°103, binarized symbols B, , B representing red and ink dragonfly images and yellow and ink dragonfly images, respectively.

is output. The binarized symbols B*, Bc, and Bs are input to the R, G, and 8 image memories 111, 112, and 113, respectively, and the R, G, and 8 image memories 111, I
I 2. In I I 3, the binarization symbols B, , B, . . .
Write Bl.

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 take an image of the register mark on the web 10.

Furthermore, the timing control circuit 110 outputs the image input signal ■ to the data calculation processing unit 130 when the detection signal DT is input, and the data calculation processing unit 130 at this time outputs the image input signal ■ to the memory control circuit 1
The R, G, B image memory IIT is controlled by the control signal CT output to the R, G, B image memory IIT.

112.113 from the color camera 50 to the binarization circuit 10
Write the binary image of the register mark that has passed through 1, 102, and 103. After that, in the data calculation processing section 130, R, G,
Data from 8 image memories 111, 112° 113 and BK image memory 114 DI + Da + Dm +
By performing calculations and other processing using DIIK, the amount of correction in register is determined. Here, reading data from the image memory and writing data to the image memory is performed by a memory control signal MC from the memory control circuit 120 to the R, G, B, BK image memories 111, 112, 113, and 114. , a read or write instruction to the memory control circuit 120 is issued by the data calculation processing unit 130.
This is done by a control signal CT from.

Note that the K image memory 114 stores a binary image of a black registration mark obtained by arithmetic processing from the data in the R, G, and 8 image memories 111, 112, and 113.

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 color camera 50 to the web 10.
When you have finished importing the image of the registration mark above, select R, G,
8 image memories 111, 112 and 113 respectively have indigo and
An image containing ink dragonfly along with red and yellow dragonfly is stored.

First, in step S1, the data calculation processing unit 130 calculates a binary image in which black, indigo, red, and yellow dragonfly marks are separated from the data in each image memory. Next step S
2, from the binary image of the register mark of the color used as the reference for registration, the register mark (
The center coordinate position of the cross-shaped registration mark is determined, and this is used as the reference coordinate position for registration. Here, the standard color or red is often selected as the reference color for registration, but the setting of the reference color may be arbitrarily selected by the operator of the registration control device.

Thereafter, the register correction operation for each color is started, and in step S3, the center coordinate position of the register mark is determined from the binary image of the register mark of the target color to be corrected. Next, in step S4,
The difference between the center coordinate position of the determined target color register mark and the reference coordinate position is calculated in the X direction and the Y direction, that is, in the vertical direction and the horizontal direction of the printed material.

Next, a tolerance value is determined in advance for the magnitude of the difference, and in step S5, a comparison is made to see whether the difference in the calculation results is greater than or less than the tolerance value, and if the difference is larger than the tolerance value, the If the difference is less than the allowable value, the register is determined to be normal (correct) and the process moves to step S7 to correct it. will not be carried out.

Here, the tolerance value for the difference between the center coordinate position of the registration mark of the color to be corrected and the reference coordinate position is usually about 5/100, and the tolerance value is not a fixed value but can be set to other values. You may also do so. The register correction operation as described above is similarly performed for all four colors (step S8).

Next, a method of separating register marks for each color into binary images in the register control operation (step SL in FIG. 4) will be described in detail.

Fig. 5 (al to h) is a schematic diagram showing how the registration mark images are separated for each color.
This is an image containing four color register marks when imaged at 0. In the same figure, (bl, (C1, (dl) are R, G, and B binary images after being imaged by the color camera 50. figure(
In a), (b), (C1, and (d)), for convenience of explanation, ink, indigo, red, and yellow dragonflies are expressed using different lines.

As mentioned above, the R binary image ((b) in the same figure) has indigo and black dragonflies, the G binary image ((c) in the same figure) has red and black dragonflies, and the B The binary image ((d) in the same figure) includes a yellow ink dragonfly. The data calculation processing unit 130 of the register control circuit 44 first creates a binary image in which only black registration marks are separated from the RlG and B binary images. In other words, the black color marks are R and G.

Since it exists at the same coordinate position in all B2 binary images, the presence or absence of a black register mark can be determined by checking whether the pixel data at the same coordinate position in each image is common. Here, since it is a binary image, the pixel data is either "0" or "1", and by performing a logical OR operation between the pixel data, if the result is "I", the pixel on which the operation was performed This will tell you whether or not it is an ink dragonfly. A specific example of processing by the data calculation processing unit 130 is as shown in steps Sll to S14 in the flow diagram shown in FIG. Here, the pixel data used for the logical sum operation are R and G.

It is not necessary to use all the B2 binary images, and only pixel data of two types of binary images among them may be used.

The binary image (el data) of the black registration marks obtained in this way is stored in the BK image memory 114 and used to separate registration marks of other colors. That is, the R, G, and B binary images (b), (e).

If we remove the binary image (e) of the black register mark from fd), =
A binary image (f) of a dragonfly, a binary image (a little) of a red dragonfly, and a binary image (h) of a yellow dragonfly are obtained. For example, when separating a binary image of an indigo dragonfly, the data calculation processing unit 130 By calculating the difference between the pixel data at the same coordinate position of the R binary image and the black dragonfly binary image, the two of the indigo dragonfly
Value image data is obtained.

A specific example of this process is steps 315 to 318 in the flow diagram shown in FIG.

Note that the separation of the binary images of the red and yellow dragonfly is performed in the same manner as in the case of the blue dragonfly. Then, as above, R
, G, and B binary image data are stored in the R, G, and 8 image memories 111., respectively. ．． 112 and 113, and used for subsequent register control processing.

Next, a method for determining the center coordinate position of the register mark from the binary image of the register mark in the registration control operation (step S2 in FIG.
and S3) will be explained in detail.

Now, assume that the binary image of a certain color of register marks is as shown in Fig. 7 fa). The data calculation processing unit 130 of the register control circuit 44 calculates the sum of pixel data in each line in the X direction and the X direction of the binary image of the register mark, that is, in the vertical direction and the horizontal direction of the printed material. Part of the binary image data of the register mark in Fig. 7 (al) is shown in Fig. 8 (a), (
(b) and (c). For example, the total sum of pixel data for each line in the X and X directions is expressed as in the following equation.

Line sum in the X direction Line sum in the X direction Here, the size of the image is assumed to be 480 pixels in the X direction and 512 pixels in the X direction. These calculations for each line are performed in steps 320-322 in the flow diagram shown in FIG.
(line in the X direction), and steps 325-527
(line in the X direction).

The calculation result of the total sum of pixel data for each line obtained in this way is expressed in a bar graph as shown in Fig. 7(a).
For the value image, the total sum along the line in the X direction is shown in the same figure (bl
, the sum total along the line in the X direction is as shown in FIG.

The total sum of lines where registration marks exist is larger than the total sum of other lines, and by setting an appropriate threshold value for these sums, it is possible to determine the line where registration marks exist. Therefore, in order to find the X coordinate position of the center coordinate position of the register mark, extract the X coordinate position of the line whose total line sum in the Y direction exceeds the threshold value, and in order to find the Y coordinate, extract the Y of the line where exceeds the threshold value
Extract coordinates. (Step S23, 328 in Figure 9)
. Here, depending on the resolution of the color camera 50 or the blurring of the optical system, the number of lines whose line sum exceeds the threshold value is not limited to one line in both the X and 7 directions. In other words, registration marks may exist over multiple lines. If the number of lines extracted in each direction is one, the coordinate position of that line may be determined to be the center coordinate position of the register mark, and in the case of multiple lines, the average value of the line coordinate positions or other values may be determined. The center coordinate position of the register mark may be determined by the calculation method (step S24°529 in FIG. 9).

As described above, the center coordinate positions of the registration marks for each color are determined, and the amount and direction of misregistration are calculated from the difference between these coordinate positions and used for correcting the register.

In the above embodiment, as shown in FIG. 2, the color register 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 10 were used to control the color register.
By performing similar processing on a and 64b, it is also possible to correct the twist register of the plate.

It is also possible to use a color line camera instead of a color TV camera. In this case, a strobe can be used instead of a normal illumination light source, and a rotary encoder can be attached to the free roller 40 to determine the timing of image capture. good.

Furthermore, the series of processing by the data calculation processing section 130 shown in FIG. 3 can be realized by the CPU or by other circuit configurations.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need to newly use special registration marks. An aircraft register control device can be provided.

[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. A block diagram showing an example of the control circuit, FIG. 4 is a flow diagram for explaining the outline of the register control process of the register control circuit in FIG. 3, and FIGS. FIG. 6 is a schematic diagram showing the state of separation, and FIG. 6 is a flow diagram for explaining the process of separating the register mark images for each color.
Figures ta+~(C1 is a schematic diagram for explaining the process of determining the center coordinate position of the register mark, Figure 8 is a schematic diagram showing the binary image data of the register mark, and Figure 9 is a schematic diagram for determining the center coordinate position of the register mark. It is a flow diagram for explaining processing. 44... Register control circuit, 46... Strobe, 50...
... Color camera, 52 ... Beam sensor, 110.
...Timing control circuit, 111-114... Image memory, 1.20... Memory control circuit, 130... Data calculation processing unit. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4 (a) (b)
(c) (f) (g) Figure 5 (d) (e) (h) Figure 7 Figure 8

Claims (1)

[Claims] The amount of misregistration and misregistration correction direction of other colors with respect to the reference color are detected for each color, and based on the detection results, the plate cylinder of each color is moved to eliminate the misregistration with the reference 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 (e), 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 reading out R, G, and B image signals from the storage means. (b) Functional means for creating level data of a cross register mark image for each color from the R, G, and B image signals. (c) Functional means for calculating the sum of level data for each line in the vertical and horizontal directions of the cross-shaped registration mark image for each color. (d) Functional means for calculating the center coordinate position of the cross register mark from the coordinate position of the line where the sum of the level data is greater than the threshold value. (e) Functional means for calculating the amount of misregistration and direction of misregistration for each color by calculating the difference between the center coordinate position of the cross register mark and the reference coordinate position.