JPS6371352A - Registering control apparatus for multicolor printing press - Google Patents

Abstract

PURPOSE:To control the color registering in a multicolor printing press with high accuracy, by mounting a means for inputting a crisscross register mark as image data, a means for calculating the registering shift quantity between colors from the crisscross register mark and a means for performing the adjustment of registering corresponding to the registering shift quantity being calculated. CONSTITUTION:When a positional shift is generated in crisscross register marks 65-68, registering inferiority is considered to be generated. By emphasizing the gradation difference of black, blue, red and yellow by using a monochromatic sensor in a line camera and utilizing a color correction filter, the signal levels of image signals of black, blue, red and yellow are adjusted so that a white paper part becomes a value of about 200, a black part becomes a value of about 20, a blue part becomes a value of about 75, a red part becomes a value of about 110 and a yellow part becomes a value of about 150 and stored in buffers at every picture element. At first, the data of one line is read from one buffer and the change point of a signal level is detected at every pixel, and the number of times of falling, the signal level of the first falling pixel and the number of a falling pixel are stored. When registering shift is generated, the numbers of two falling pixels being stored are read and the operation is applied to calculate registering correcting quantity. Next, a correcting direction moving a plate cylinder is specified from the first falling signal level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a register control device for a multicolor printing press that automatically adjusts the register of each color of a printed matter being printed in the multicolor printing press.

[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 test print, and then adjusting the color registration using the printing press's registration adjustment device.

Normal multicolor prints have four process colors (ink, indigo, and red).

Yellow) ink is printed over a single sheet of printing paper,
There is no problem if the positional relationship of printing each color is correct, but 1
If the positional force is out of order (called misregistration or misregistration), the print quality will deteriorate significantly, and the tolerance is ±5
Registration work placed a heavy workload on printing press operators because strict accuracy of less than / 100 cm was required.

For this reason, various companies have developed and announced devices for automatically adjusting color registers in multicolor printing presses.

As an example, a register adjustment device disclosed in Japanese Patent Application Laid-Open No. 60-129261 attempts to adjust the color register before starting printing by placing special marks on the printing plates and adjusting the positional relationship of the printing plates. However, in this device, it is laborious to place marks on the plate material. Even if the positional relationship b' of the plate materials matches, there is a drawback that accurate registration cannot be achieved due to the expansion and contraction of the printing paper, so it is not actually used much. In addition to the above, there is also a device that uses an optical sensor to read special marks printed in each color on the printing paper and performs registration, but even with this device, it takes a lot of effort to add special marks and wastes paper. Major problems such as 6” remain.

[Problems to be Solved by the Invention] The present invention has been made in order to cope with the above-mentioned circumstances, and is used in a multi-color printing press, and has a simple configuration and can accurately color colors without using special registration marks. It is an object of the present invention to provide a register control device for a multicolor printing press that can adjust the register.

[Means for solving problems]

The register control device for a multicolor printing press according to the present invention includes means for inputting cross register marks conventionally used in plate making as image data without inserting special register marks;
The apparatus includes means for calculating the amount of misregistration between each color from the cross register mark, and means for adjusting the register according to the calculated amount of misregistration. [Function] According to the present invention, in a multicolor printing press, each color can be automatically registered using the cross register marks conventionally used in plate making, without adding special registration marks. Can be done.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a register control device for a multicolor printing press according to the present invention will be described below with reference to one drawing. FIG. 1 is a schematic diagram showing the overall configuration of the present invention. here.

Although an embodiment adapted to an offset rotary printing press will be described, there is no problem even if the target printing press is an offset sheet-fed printing press.

A roll-shaped paper web U■ is sent to printing units (20a) to (
20d), ink, indigo, and red in each unit.

Patterns in each color of yellow are printed persistently. For example, the ink unit (20a) includes a plate cylinder (22a) for printing one page, a rubber cylinder for clothing (24
a) Consists of a practical blanket cylinder (26a) and a practical printing cylinder (28a), and when the web OC passes between the two blanket cylinders, black ink is transferred under pressure and printing is performed. . This is another unit (20b).

The same applies to (20c) and (2nd). 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 order to register each color, the phase adjustment is carried out in the rotational direction of the plate cylinder, its rotational axis direction, and its rotational axis direction. The phasing motor (21a) provided on each plate cylinder as disclosed in
λ (21b).

(21c) and (21d) and is well known, so a detailed explanation will be omitted here.

The web 0ω which has been printed in each color by each printing unit is dried with hot air in a dryer (2), cooled in a cooling section, and discharged through a web path section (2) and a folding machine section.

Here, a free guide roller (40 (hereinafter referred to as a free roller)) is provided in a part of the web path section (b), and a rotary encoder (four rotary encoders are coaxially attached to the free roller (41). Also.

Illuminates the web 0ω wound around a free roller (40).

light source + 46) and a line camera (5) that converts reflected light into electricity.
■ is provided.

Here, the line camera 150) has a CCD type line sensor, which has many advantages in terms of signal processing, but there is no problem in using other input means (one sensor, area sensor, etc.). A reflective beam sensor (S2) is installed just before the line camera 6■ in the direction of travel of the web.
This is a pattern (b) that is printed continuously on roll paper 11G.
) is used to read the start mark (stock) provided at the printing start position.

Figure 2 shows the relationship between the pictures and the start mark. here,
If the start position of the pattern can be determined to some extent from the rotation of the plate cylinder (23, etc.), the start mark @) and reflective beam sensor @) are unnecessary. These line camera marks are used to control the timing when inputting the cross mark (64) in the picture in line 5.

Rotary encoder (timing pulse TP from 4
The drawing method signal IS from the line camera 5G and the start pulse SP from the reflective beam sensor (E2) are input to the registration control circuit, the amount of registration between each color is calculated, and the amount of registration between each color is calculated accordingly. Motors (21a) and (21b) for phase alignment of the plate cylinders of the printing unit.

(21c) and (21d) are driven to complete registration.

Here, registration may be controlled for all consecutive printed matter, or may be controlled once for every few sheets.

FIG. 6 shows a block diagram of the register control circuit (2).

The image signal IS from the line camera (50 pixels) is digitized by the A/D converter (ioo), and only the data required by the data selector (120) is written to each buffer (140 x 140) for each pixel. It's complicated.

Here, the start and stop of capturing image signals from the line camera T50 is based on the start pulse SP from the 1 reflection type beam sensor (52) and the timing pulse TP from the rotary concoater (43) (timing control circuit (IIO)). At this time, necessary data such as the distance between the start mark and the cross register mark is set from the CPU (170) to the timing control circuit (110).
120) and data selection in the buffer (14)
0X140)... is controlled by the memory control circuit (130) in response to instructions from the CPU (170).

The data read from the buffers (140) (140)... is sent to the CPU (170), and the CPU
At step (170), misregistration is detected and its amount is calculated, and a correction signal corresponding to the calculation result is output to the plate cylinder phasing motor.

Next, register control using the circuit configuration as described above will be explained in more detail.

FIG. 4 shows an example of cross-shaped registration marks for each color. The cross mark is a typical mark that has traditionally been used for registration in platemaking and printing, and is included in almost all ordinary printed matter. For this reason, if registration can be automated using cross register marks, there will be no increase in the load on the previous process, which has the advantage of simplifying the introduction of the device and improving accuracy.

Each cross register mark is printed in four colors: ink, indigo, red, and yellow, but only the cross register mark Tc, which is the standard color for registration, has a perfect cross shape (shown with a solid line), and the other The cross register marks of the five colors have a partially missing shape (indicated by broken lines, dashed lines, and diagonal lines), so when the cross register marks of the four colors are overprinted, the cross register marks of the standard color and the cross register marks of each color are Care is taken so that the PI line and the horizontal line have portions where six or more colors do not overlap.

As will be described later, this allows the amount of misregistration between the reference color and other colors to be determined.

1.Although some ingenuity is required for the discrimination algorithm,
Using the same idea, even cross-shaped registration marks with missing parts where six colors overlap can be handled.

Here, 1. Normally, indigo or red is often used as the reference color, the thickness of the cross mark is 0.1ON, and the length of both vertical and horizontal lines is often in the range of 10 to 20 mm, but one Even in the invention, it is possible to use indigo or red as the reference color and use cross-shaped registration marks of the above dimensions.

Further, as long as it has the above-mentioned conditions for the overlapping portion and has vertical and horizontal line forces to such an extent that it does not impair one of the original functions of the cross register mark.

The shape of the cross mark is not limited to this embodiment.

FIG. 5 shows the state of the cross register mark (64) after printing.

As mentioned above, the solid line indicates the standard blue cross mark (65), the broken line indicates the yellow cross mark (66),
The one-dot chain line is the ink cross mark (67χ) The diagonal line is the red cross mark (68). These cross marks (65) to (68) should overlap completely when they are in register. However, in Figure 4, all the cross register marks are misaligned, indicating that misregistration has occurred.Therefore, in order to correct misregistration, it is necessary to match each color to the standard color. It would be a good idea to eliminate the positional deviations of the four color cross register marks.

As mentioned above, in order to input the cross register mark as image data, a line camera et al.
The start mark (62
) is read by the reflective beam sensor (52), the timing pulses from the rotary encoder (4) are counted by a predetermined number, and then manual operation can be started.

In addition, the distance between the start mark and the cross mark can be set in a constant relationship during plate making, so that the swimming control circuit (110) can start and stop capturing the image signal from the line camera (50). It is also possible to selectively store data at a predetermined location by a memory control circuit (1).

In this embodiment, the memory control circuit (130) O
Due to the control, only the vertical and horizontal lines of the cross mark overlap in two colors, that is, arrow A in FIG.

Pixel-by-pixel data of lines along lines B, C, D, E, and F are stored in separate buffers (140), respectively. That is, pixel data along arrows A and B1C is used. Then, the misregistration between the reference color and other colors in the direction of the rotation axis is detected and the amount of misregistration is calculated.

Pixel data along arrows E and F are used to detect misregistration between the reference color in the direction orthogonal to the rotation axis and other colors, and to calculate the amount of misregistration.

The CPU (170) detects misregistration and calculates the amount of misregistration.
This will be explained based on FIGS. 6 to 8.

Figure 6 shows the signal levels from the A/D converter (10) for black, indigo, red, and yellow image signals. If the A/D converter (100) performs 8-bit OA/D conversion by emphasizing the gradation difference between each color, within the range of minimum O1 and maximum 255, the blank area will be approximately 2
00, black part about 20, lid part about 75. The red part is about 110.
The position is adjusted to a value of about 150.

FIG. 7 shows the signal level of data stored pixel by pixel in each buffer in the lines along the arrows A, B%C in FIG. The data in part A is used to detect misregistration in the rotation axis direction of the reference colors indigo and yellow and calculate the amount of misregistration, and parts B and 0 are used for similar calculation processing for indigo and red, and indigo and black, respectively. The misregistration detection and misregistration amount calculation will be explained based on FIG. 8 with reference to FIG. 7 as described above. First, data for one line is read from one buffer (Sl). The signal level of this data is checked for each pixel, and the rising and falling points of the signal, that is, the points of change in the signal level, are detected. The pixel number is stored (S2).

Next, from the number of times the signal falls, the number of times the signal falls is only one, because when the register is in alignment, the two cross register marks are in perfect alignment.b '= When misregistration occurs, as shown in FIG. 7, the signal level decreases in the overlapping portion of the two colors, so a second signal falling phenomenon occurs. Therefore,
If the number of falls is only one, the register is correct and there is no need to correct the register (88), and if the number of falls is two, it can be determined that misregistration has occurred.

If it is determined that misregistration has occurred, the amount of misregistration, in other words, is determined by reading the stored pixel numbers Pm1 and Pm2 of the two falling pixels and calculating (Pm1-Pm2)Xr. Calculate the amount of register correction (S4)
. Here, Pmj-Pm2 is the number of pixels between two falling pixels, and r is the dimension of the printing paper surface corresponding to one pixel.

Next, in step S5, the direction in which the printing plate should be moved (correction direction) in order to correct the misregistration is specified from the first falling signal level.

+n+-A-x If you turn the υ♀repent h”s hill of the six swords to the right, the target color is shifted in the +X direction from the reference color in Figure 7 b '-It turns out.

Therefore, in order to correct this deviation, it is sufficient to move the plate cylinder of the target color in the -X direction, and if the signal level of the first falling edge of t is not the reference color, then It is determined that the color is deviated from the reference color in the -X direction or the +y force direction.

Therefore, it is sufficient to move the plate cylinder of the target color in the opposite direction.The color to be corrected, its correction direction and correction amount obtained in steps S4 and S5 are sent from the register control circuit (44) for that color. A control signal M is sent to the register control motor of the printing unit corresponding to
The misregistration is corrected by operating the register control motor b'' in response to the signal MC (S6).

Note that data on lines along arrows E and F can be processed in exactly the same way.

By performing the above processing on all of the lines A, B, C, D, E, and F stored pixel by pixel in each buffer, the rotation axis direction of each color and the direction orthogonal to the rotation axis can be The deviation with respect to the reference color is corrected, and as a result, the registers of the four colors match 6''.

In this embodiment, as shown in FIG. 2, the control was performed only on the cross mark (64a) immediately after the start mark, but the same process is performed on the two cross mark (64a) and (64b) in the flow direction. By doing so, it is also possible to correct for twisting of the plate.

Also, since two falling points are used among the signal level change points to calculate the amount of misregistration, the midpoint of each color registration mark is found from the 12 rising points or each change point, and the amount of misregistration is calculated based on this. You may also calculate the CPU of FIG.
All of the processing in (170) can also be implemented by a circuit configuration.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to control the color register in a multicolor printing press with high precision by using the conventional cross mark without adding special marks.
can.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of 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 an embodiment of a register control circuit. Block diagram showing. FIG. 4 is a schematic diagram showing one embodiment of the cross register mark, and FIG. 5 is a schematic diagram showing the state of the cross register mark after printing. FIG. 6 and FIG. 7 are schematic diagrams showing the state of the measurement signal. FIG. 8 is a flowchart of processing in the CPU. (42)...Rotary encoder (SO)...Line camera (i oo)...
Person/D Konno (-ta (64)...Cross dragonfly (150)...Fresh halt circuit (170)...
...CPU Patent questioner Toppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 2 Figure 3 Figure 5! L & Figure 6 Figure 7 Figure 8

Claims (3)

[Claims] (1) The amount of misregistration and misregistration correction direction of other colors with respect to the standard 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 standard color. In a register control device for a multicolor printing press that matches color registers, an input means for inputting an image of a cross-shaped registration mark to be printed with a pattern at a different signal level for each color, and a change point of the input signal level. The method is characterized by comprising a misregistration amount calculation means for calculating the misregistration amount from the reference color, and a misregistration correction direction determining means for determining the positional relationship of the other color with respect to the reference color from the signal level and determining the misregistration correction direction. Register control device for multicolor printing presses. (2) The register control device for a multicolor printing press according to claim 1, wherein the input means is a monochrome line camera. (3) The register control device for a multicolor printing press according to claim 1, wherein the input means is provided with a color correction filter so that a sufficient difference in signal level occurs between each color.