JPH0471850A - Registration regulating method and device - Google Patents

Abstract

PURPOSE:To enable registration of each color to be automatically performed without marking a specific registration mark by a method wherein after enlargement photographing of a drop out part of a print surface with a color camera, side enlarged image is separated in color into four colors of sepia, yellow, red, indigo, a shift amount of each color from a boundary of the drop out part is calculated from said separated image, and a phase of a plate cylinder is adjusted based on said calculated value. CONSTITUTION:In order to input a drop out character of a pattern of a web 7 wound around a roller 10, a strobe 13 capable of condensing light on a print surface with an optical fiber, and a sensor unit 11 in which a microscope or the like capable of enlargement photographing is equipped with a color television camera are provided. Further, output from this color camera is separated in color into image signals R, G, B, and is inputted to a registration regulating circuit 20. A shift amount of each color is calculated by detecting a boundary of a no ink part of a part of a drop out character from each image, and a plate cylinder phase registrating motor 2a, 2b, 2c, 2d of each printing unit to be required according there-to is moved to complete registration.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an adjustment device applied to registration of printing machines!
and its method.

[Conventional technology]

Conventionally, when manually registering each color on a multicolor printing press, a person would perform a test print to check the amount of misregistration for each color, and then adjust the color register using the printing press's register adjustment device7. Multicolor prints are processed using 4 colors (C, M, Y, Bx
) ink is printed over a sheet of printing paper, and if the positional relationship of the printing of each color is correct, there is no problem, but if the positional relationship is incorrect (called misregistration or misregistration), the print quality will deteriorate. The tolerance is (±5/100).
) Registration work, which required strict precision of less than wh, was a heavy burden on the printers of the printing press.

For this reason, various devices have been developed to automatically adjust color registers in multicolor printing presses.

As an example, print in each color on printing paper! There is a device that performs registration by reading the special marks made using an optical sensor.

However, with this device, special (dedicated) marks are inserted around the image when printing the plate. This mark requires insertion precision.

This is because the register adjustment device stores the mark spacing in advance, and only compares the stored value with the actually printed mark spacing, without being aware of the actual pattern. Multi-color printing machines print by overlapping multiple plates, so one or more marks are printed in a predetermined position on each plate, and when each color is printed, the above memorized values are set. Each plate must be carefully imprinted. Therefore, an additional burden will be placed on the prepress department.

The reason why each color and mark must be inserted at predetermined positions at regular intervals is that the detector does not distinguish between the colors of each mark, but only the positional relationship. This is because it is being measured.

Recently, some color cameras have also taken color into consideration, but they have only simplified color discrimination by devising mark positions so that colors do not overlap. .

[Problem to be solved by the invention]

The above-mentioned conventional technology has the following problems.

(1) The original pattern is fixed (unrelated special marks must be inserted to align the pattern).

(21%) This places a burden on the plate-making department that inserts registration marks or registration marks.

(3) Since registration marks for each percentage are used, unnecessary blank space is required.

(4) This is an indirect method of registering with a special mark, and even if the register of the special mark is correct, there is a risk that misregister n of the printed pattern may remain. In particular, the misregistration of white characters is noticeable, so the operator needs to make adjustments again.

[Means to solve the problem]

To target white blank characters or a portion equivalent to white blank characters in a printed pattern without inserting a special registration mark.

means for inputting an enlarged image of white blank characters or a portion corresponding to white blank characters; means for detecting each color from the image data and calculating the amount of misregistration between the colors; and means for making adjustments.

[For production]

To automatically register each color in a multicolor printing machine by using an actual pattern (white characters) without inserting a special registration mark.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a register adjustment device for a multicolor printing press according to the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 is a schematic diagram showing the overall configuration of 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 or other multicolor printing press.

A roll-shaped web 7 is supplied to printing units (1a to 1d), and each unit prints light, indigo, red, and yellow in this order.

(For example, Sumi Units) la is the clothing plate cylinder 3a.

It is composed of a clothing blanket cylinder 4a, a back blanket cylinder 5a, and a back plate cylinder 6a, and when the winding paper 7 passes between the two blanket cylinders, black ink is transferred under pressure and printing is performed. It will be done.

This is the same for other units) Ib, lc, and Id.

Here, only the registration on the front side of the printing paper will be explained, but the same is true for the back side, so the explanation will be omitted.

In order to register each color, the register is adjusted by adjusting the phase of the plate cylinder 3 in the direction of rotation and its axis of rotation. , 2b, 2c, and 2d. The roll 9 paper 7 that has been stamped with each color in each printing unit is
It is dried with hot air in the drying section 8, cooled in the cooling section 9, passes through the web path section 15, and is discharged through the folding section 14.

Here, a 7-lead guide roller 10 (hereinafter referred to as a roller) is provided in a part of the web path unit 15, and an optical fiber is used to input the outline characters of the image on the web 7 wound around the roller 10. A strobe 13 that can focus light on the printing surface, and a sensor unit 11 consisting of a microscope or other device capable of magnifying photography with a color television camera attached are provided. Also, the output from this color camera is R, G,
The B image signal is color-separated and input to the registration adjustment circuit I, which detects the boundary of the part of the white character without ink from each image, calculates the amount of deviation of each color, and calculates the amount of deviation of each color accordingly. Motor 2 for plate cylinder phase alignment of each printing unit
Move a + 2 b + 2 c + 2 d to complete the registration. Here, the registration may be adjusted for all consecutive prints, or may be adjusted once for every few sheets.

Here, the combination of the color television camera and the strobe 13 may also be a combination of a color line sensor and a non-volatile light source. A reflective beam sensor called a mark sensor is installed immediately in front of the sensor unit 11 in the direction of travel of the web 7, and this is used to detect the patterns that are continuously printed on the web 7. This is for reading the start mark I (FIG. 7) provided at the printing start position of the printer. Start mark I detected by mark sensor
may be placed in the margin of the roll paper 70 as shown in Figure 7, or
If you do not wish to insert the start mark I, it may be inserted at the beginning 31 of the actual printed image itself.

Further, a rotary encoder 21 is attached to the roller 10, and by counting pulses in response to a start signal from the mark sensor port, any point of a white character in the vertical direction can be treated as a measurement point. Also, as shown in Figure 2, the sensor unit 11 is assumed to be able to move freely in the left and right directions, and any point on the pattern can be set as the measurement area! It is possible to do this.

FIG. 2 shows a case where a color camera is attached to the senna unit 11. In the case of a line sensor, it is almost the same; what is obtained is an R, (1,, B image), and the process of calculating the amount of misregistration is the same.
In the figure, the winding and the pattern on the paper are taken into the register adjustment circuit in the following order. The timing best robot of the rotary encoder 21 is caused to emit light, and the light is passed through the entire optical fiber n and irradiated onto the printed web 7. The reflected light is observed under a microscope.
1iii'gj to the extent that the halftone dots can be observed through the
! Then, an image is formed on the color TV camera head. This signal is converted into R, G, and B image signals by the camera controller 5 and sent to the register adjustment circuit.

Next, a processing method in the register adjustment circuit Kasai will be explained.

Image signals for each color of R, G, and B from the camera controller 5 are stored in each frame memory. Then, each of the image signals is binarized using a set threshold value. However, this set value can be corrected depending on the operating conditions.

Binarization of the obtained R, e, B i! In the iI image, indigo, red, and yellow ink adhesion parts, which are complementary colors, can be detected.

Regarding black, determination is made based on the fact that ink is commonly attached to all R, G, and B components. However, this method has the problem that it is difficult to distinguish between the illuminated parts of the ink and the three colors of indigo, red, and yellow that overlap.

An example of an image of a white character as shown in FIG. 3 will be shown, and its characteristics will be described. ``White characters have ink deposits on both sides of the blank paper.'' The width and concurrency vary slightly depending on the font, but it always exists. If the width is wide, you can measure it in two places across from the blank part, and it will be the same, so it will be omitted. The misregistration n is measured based on the amount of ink shift on both sides of this blank paper area. Broadly speaking, there are two patterns of this shift as shown in FIG.

As in pattern 1, one side is second and the other side is third (as seen from the blank paper with white ink letters), and as in pattern 2, one side is first and the other side is fourth. There are two ways in which this happens.

Indigo, red, and yellow, which are colors other than the above black ink, exist as a single color or in two-color overlap in the blank area between the ink and ink, except that only in the case of ζ turn 2, three-color overlap exists. Basically, 2
Since the colors overlap, it can be detected by binarizing using the complementary color relationship, so there is no problem with the order of these three colors.

Therefore, only two patterns with different ink positions are a problem, and this point will be considered below.

FIG. 5 shows how the printed material shown in FIG. 4 was measured using a color television camera. Also, FIG. 6 shows R, G.

These are images obtained by binarizing a B6 image signal using a preset threshold value, where ■ indicates three images in which yellow is detected, ■ indicates zero images in which red is detected, and ■ indicates eight images in which indigo is detected. Also, ■ is an image that extracts only the common parts of ■■■, black and yellow m,
When the three colors of red (M) and indigo (C) overlap, a dark gray can be detected.

- In the case of turn 1, the shift amount of indigo based on black can be detected as a3ao from the left side of the blank page. Next, from the right side〃1, the amount of deviation between yellow O□-bo and red b2-bo can be measured. However, a. -a3゜bo-b3 is
Indicate the position of the boundary line with each blank sheet.

For pattern 2, ao=al=a from the left side of the blank section
2 is equal to a3, and from the right side there is a red b2
-bo and yellow, -b. can be measured, so it can be determined that ao is always black. This is because it is known that red and yellow are shifted from the right side, so there can be no CMY color mixture at the ag point on the left side. Therefore, in this case, first shift the ink little by little to the side where the edge of ■■■■ is the same (left side in the figure) until it becomes the same as turn 1 at .

In other words, shift until at least one color appears on the blank page, both ink and black. Thereby, pattern 2 can be measured in the same way as nozo turn 1.

However, as a special case, aO” 'l ” a2 =
There is a case where A3 and bo = bl = b2 = b3, but in this case, one side is black and the other is CMY mixed color, and the black is moved to either side so that the blank area (M width) becomes the maximum. Adjust so that the time is accurate.

Further, in the above description, edges in the vertical direction, that is, misregistration in the left and right directions were described, but edges in the horizontal direction, that is, in the vertical direction can also be measured in the same way.

Therefore, it is sufficient to use two locations on the top, bottom, and left and right as measurement areas, but some characters may not have vertical or horizontal edges. The amount of vertical deviation can be calculated.

Furthermore, even if the halftone dot area ratio around the white characters is not 100, the boundary line can be measured by tracing the outline of the halftone dots on the blank side.

In addition, in order to measure at two locations, the sensor unit 11 has two locations.
A stand is sufficient, but there is no problem in terms of productivity even if you use one stand and move it every few pieces to measure it.

In addition, the amount of deviation may be measured simultaneously at the corners of white letters, both vertically and horizontally.

FIG. 8 shows the overall processing flow.

First, the operator instructs the measurement location by using means such as photographing the entire printed matter using a line sensor of the horizontal printed matter placement device. In this case, since location information is required, color is not a concern. This image is displayed on a monitor television, and the operator indicates the measurement area using a power button or the like.

Alternatively, a reasonable method may be to spread the print sample on a color booth and input the position using a digitizer. Then, the sensor unit 11 shown in FIG. 2 starts moving. At this point, it is determined whether the designated measurement location is part of a white character as shown in FIG. This determination can also be automated by using a discriminant analysis method among the binarization methods. If there is no character, it is necessary to repeat until the character part is found. In this case, positioning will be made easier if the microscope n is equipped with a field of view expansion function such as a zoom mechanism. If the character part is found, binarize the color separation for R, G, B, @image, identify the pattern, and if it is pattern 2, first move the black ink slightly, and then measure the register with pattern 1. ,
Adjust the plate cylinder position.

Since the positional relationship between the sensor unit 11 and the pattern does not change during continuous printing, misregistration can be monitored and adjusted by repeatedly capturing the pattern and measuring the registration.

[Effects of the Invention] The present invention provides a registration method and apparatus for a multi-color printing press equipped with a plurality of printing units, in which a white area on a printed surface is enlarged and photographed using a color camera, and then the enlarged image is colored in black, yellow, black, yellow, etc. Separate the colors into four colors: red and indigo, calculate the amount of deviation from the border of the white part of each color from the separated image, and based on the calculated values,
Adjusting the phase of the plate cylinder has the following effects.

■ No special marks are added, which saves time and effort in the prepress department.

■ Since no special marks are included, extra space on printing paper is not required, resulting in paper savings.

■ Since the register is adjusted using the white letters inside the picture, where misregistration is often noticeable, accuracy is improved compared to when register is adjusted using marks outside the picture.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a commercial rotary offset press according to an embodiment of the present invention, FIG. 2 is an enlarged view of the detection section in FIG. 1, FIG. 3 is a diagram showing an example of a detection target, and FIG. Figure 3 is an enlarged view of each pattern, Figure 5 is a diagram showing the camera output of Figure 4, Figure 6 is a diagram showing the color separation results of Figure 5, Figure 7 is a diagram showing an example of a printing machine, FIG. 8 is a processing flow diagram of the present invention. 1a to 1d... Printing unit 7... Winding paper 1
0...Free guide roller 11...Sensor unit 13...Strobe Add...Register adjustment circuit agent Patent attorney Shige Okamoto 1st person outside 3rd m + 4th leg free guide roller child Goql ( ii] Failed figure 5 Ha0 turn 1 Bagoon 2 Zrishio 2Zri ZZ small □ 〃U2'4
riZ49n Otsuuri z 1 Otsu◇n 2
ri〆ItIIIt-III〆1-II♂trlq times

Claims (2)

[Claims] (1) In the registration method of a multicolor printing press equipped with multiple printing units, after enlarging and photographing the white part of the printing surface with a color camera, the enlarged image is
A register adjustment method characterized by separating each color into colors, calculating the amount of deviation between each color and the boundary of a white part from the same separated image, and adjusting the phase of a plate cylinder based on the calculated value. (2) In a multi-color printing press equipped with a plurality of printing units, there is a means for enlarging and photographing the printed surface, and a means for photographing the photographed image in black and black.
The present invention includes a means for color separation into four colors of yellow, red, and indigo, a means for calculating the amount of deviation of each color from the color-separated image, and a means for adjusting the phase of the plate cylinder based on the calculated amount of deviation. Characteristic register adjustment device.