JP4114329B2 - Density target setting method, density management method, density target setting device, density management device, and offset printing machine equipped with them - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to offset printing using inks of at least four colors of black, indigo, red, and yellow, and is suitable for managing the density of printed matter on the paper surface. The present invention relates to a method, a density target setting device, a density management device, and an offset printing machine including the same.
[0002]
[Prior art]
Conventionally, the ink key control device controls the density as a target when all the colors are predicted before printing, and the density obtained as a result of color matching performed by the printing press operator during printing for all colors. The case was proposed.
[0003]
At this time, it is difficult for the former to predict the density of each color that can guarantee the quality of the pattern before printing. Further, since the appropriate density differs depending on the paper, the desired print quality cannot be obtained. It was.
[0004]
In the latter case, color matching is completed quickly by highly skilled operators. However, in reality, there are few operators with such high skills, so time and paper are consumed until color matching is completed. Since the print quality depends on the operator, there is a problem that density variation occurs between lots or in the surface of a single printed matter.
[0005]
In particular, when performing color matching of ink, human vision is less sensitive to high-density ink, so time and paper are more likely to be consumed before color matching is completed. There was a problem that the shadow area of the ink was crushed, or the ink density was lowered due to insufficient ink ink, and the desired print quality could not be obtained, for example, the gradation of the ink shadow area was lost. .
This problem is often seen in items such as publications in which black with a high halftone dot area ratio is frequently used, for example, publications in which characters and background are solid black.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art. For all colors, when managing the density of printed matter based on the density target of each color predicted before printing, all colors are printed. Problems that occurred when humans (typically the operator of the printing press) performed the color matching of each color as a density target for each color and managed the density of the printed material based on them. It is an object of the present invention to provide a novel density target setting method, density management method, density target setting apparatus, density management apparatus, and offset printing machine including them.
[0007]
[Means for Solving the Problems]
First, as shown in claim 1, in offset printing using ink of at least four colors of black, indigo, red, and yellow, in a density target setting method for managing the density on the paper surface of the printed matter,
For black, the density predicted before printing is set as the density target, and for at least three colors of indigo, red, and yellow, the density of each color is determined based on the result of color matching after the start of printing. Is set as a density target for each color, and a density target setting method for printed matter.
[0008]
The invention of claim 2 is the density target setting method for printed matter according to claim 1, wherein the density of the solid portion of each color is used as the density target of each color.
[0009]
The invention of claim 3 is characterized in that the ink key of each color is adjusted based on the density target of each color obtained by the method for setting the density target of printed matter according to claim 1 or 2. This is a density management method for printed matter.
[0010]
The invention of claim 4 is used for offset printing using inks of at least four colors of black, indigo, red and yellow, and sets a density target for managing the density on the paper surface of the printed material. In the device
Black density target input means for inputting the black density target predicted before printing ;
Measuring means for measuring the density of indigo, red, and yellow on the printed paper surface for at least three colors of indigo, red, and yellow;
A density target for printed matter, comprising: density target input means for inputting each color density target based on density data of at least three colors obtained by using the measurement means; This is a setting device.
[0011]
According to a fifth aspect of the present invention, there is provided the density target setting device for printed matter according to claim 4, an ink key adjustment control means for controlling the adjustment of the ink key for each color based on the density target for each color set by the setting device, A printed matter density management apparatus comprising the above.
[0012]
According to a sixth aspect of the present invention, there is provided an offset printing machine comprising the printed matter density management apparatus according to the fifth aspect.
[0013]
The density target referred to in the present invention may be a constant value or may be any target having a certain range.
[0014]
According to the present invention, printing quality and productivity are improved, and this effect is particularly noticeable in items such as publications in which characters having a high halftone dot area ratio are frequently used, for example, letters and backgrounds made of solid black. Appear in That is,
(A) Productivity is improved because the time and paper required for ink color matching are reduced.
(Ii) Since the ink density does not depend on the operator, there is no variation in the ink density between lots or within the surface of a single printed matter, so that the print quality is improved.
(Iii) Since the appropriate black ink is supplied on the black plate, the black ink will not be crushed due to excessive black ink, or the black ink concentration will not decrease due to insufficient black ink. The gradation in the shadow area is richer and print quality is improved.
(E) Since there is no color matching work for ink, the operator can concentrate on the color matching of indigo, red and yellow, and the balance of indigo, red and yellow is improved, and the printing quality is improved.
There are the effects as described above.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing a part of a BT full-size BB offset rotary press provided with an ink key control device for controlling the density on the paper surface with an arbitrary value as a target value.
[0016]
FIG. 2 shows an optional rotary press 10 that can use four colors of ink by having the black unit 11, the indigo unit 12, the red unit 13, and the yellow unit 14 as shown in FIG. Conventionally proposed in the ink key control device 20 that measures the density on the printing paper 15 using the measurement camera 22 with the value as a target value, calculates with the control arithmetic device 21, and controls the ink key via the cable 23. 1 shows a density target setting method and a procedure of one embodiment according to the present invention.
[0017]
In FIG. 2, 30 is one of the conventionally proposed methods, 31 is the color to be controlled, 32 is the work of predicting the density target of black, indigo, red and yellow from past data, and 33 is the ink key. An operation for inputting black, indigo, red, and yellow density targets to the control device, and 34 is an operation for starting control of black, indigo, red, and yellow using an ink key. Hereinafter, the above-described method is referred to as Conventional Method 1.
[0018]
In FIG. 2, 40 is also one of the conventionally proposed methods, 41 is the color to be controlled, 42 is an operation in which the operator performs color matching of black, indigo, red and yellow during printing, 43 Is the work of determining the density of ink, indigo, red, yellow as a result of the color matching of the ink, indigo, red, and yellow by the operator during printing. 44 is the ink and indigo to the ink key control device. 45, the operation of inputting red and yellow density targets, and 45 the operation of starting control of black, indigo, red and yellow using the ink key.
(Hereinafter, the above method will be referred to as “conventional method 2”.)
[0019]
In FIG. 2, 50 is an implementation procedure using the present invention, 51 is a color for predicting a density target from past data before printing, 52 is an operation for predicting a black density target from past data, 53 Is an operation for inputting a black density target to the control device, 54 is a work for starting the black ink control using the ink key, and 56 is an object to be controlled with the density as a result of color matching performed by the operator during printing. , 57 is an operation in which the operator performs color matching of indigo, red and yellow. 58 is a result of the operator performing color matching of indigo, red and yellow during printing. An operation for determining as a density target, 59 is an operation for inputting indigo, red and yellow density targets to the ink key control device, and 60 is an operation for starting control of indigo, red and yellow.
[0020]
【Example】
(1) Comparative Example 1
Here, an example of the conventional technique implemented in the procedure shown by 30 to 34 in FIG. 2 and the result are shown.
As an execution procedure, first, for black, indigo, red, and yellow 31, using work 32 to predict an appropriate solid density of each color from past data, black is 1.6, indigo is 1.2, We predicted that red was 1.2 and yellow was 1.1. Next, an operation 33 for inputting the value as a target value to the ink key control device is performed, and an operation 34 for starting the control of black, indigo, red, and yellow from the start of printing is performed.
[0021]
As a result, although there was almost no variation in the density of each color between lots or within one printed sheet, the balance of indigo, red and yellow was poor, and the desired print quality could not be obtained.
[0022]
(2) Comparative Example 2
Here, another example of the conventional technique implemented by the procedure shown by 40 to 45 in FIG. 2 and the result are shown. As an execution procedure, first, in the ink, indigo, red, and yellow 41, after the operator of the printing press finishes the color matching operation 42 for the proof, the density of ink, indigo, red, and yellow obtained from the result is obtained. The operation 43 for determining as a target concentration was performed. Next, operation 44 for inputting the target values of black, indigo, red, and yellow to the ink key control device was performed, and then operation 46 for starting control of black, indigo, red, and yellow was performed.
[0023]
As a result, printed materials with a good balance of indigo, red, and yellow were obtained, but variations in the density of each color were observed between lots and within the surface of one printed material. Due to this variation, for example, the density of characters composed of solid black ink became non-uniform, and there were cases where the print quality was significantly reduced. In some cases, an operator takes more time than necessary to complete color matching, and the operator consumes 2000 or more printing sheets.
[0024]
(3) Example 1
Here, one embodiment according to the present invention carried out in the procedure shown in FIG.
As an execution procedure, first, in black 51, it was predicted that black was 1.6 using operation 52 for predicting an appropriate black density from past data before printing.
Next, an operation 53 for inputting the black target value to the control device was performed, and an operation 54 for starting the black control was performed. For indigo, red and yellow 56, after the operator finishes the indigo, red and yellow color matching operation 57 for the proof, the resulting indigo, red and yellow concentration is determined as the target concentration. 58.
Here, the operation 59 for inputting the target values of indigo, red and yellow to the ink key control device was performed, and then the operation 60 for starting the control of indigo, red and yellow was performed.
[0025]
Here, since the ink is not dependent on the operator, there is almost no variation in the density of the ink between lots or within a printed sheet. In addition, since the appropriate black ink is supplied on the black plate, the black ink shadow is not crushed due to excessive black ink, or the black ink density is not reduced due to insufficient black ink. The shades of the ink shadows have become richer, and the quality of the characters that are composed of the solid ink and the white characters in the solid ink area have also been improved.
In addition, since the work of color matching of ink has been eliminated, the time and paper required for color matching of ink have been reduced, so productivity has been improved, and the operator has been able to concentrate on color matching of indigo, red and yellow. Productivity and quality improved dramatically, with the balance of indigo, red, and yellow in about 800 sheets after the start of printing.
[0026]
【The invention's effect】
In Comparative Example 1, although there is almost no variation in the density of each color between lots or within the surface of a printed material, the balance of indigo, red and yellow is poor, and the desired print quality cannot be obtained. was there.
[0027]
In Comparative Example 2, a printed material with a good balance of indigo, red, and yellow was obtained, but variations in the density of each color were observed between lots and within the surface of one printed material. In some cases, the density of characters, etc., was uneven and the print quality was significantly reduced. In addition, there are cases where it takes more time than necessary to complete the color matching depending on the operator, and there is a problem in that the operator consumes 2000 or more printing sheets.
[0028]
In other words, according to the present invention, by appropriately setting a target for each color, the density predicted before printing for all the colors is controlled as the density target, and the operator of the printing press can print all the colors during printing. It is possible to propose a new density target setting method, density target setting device, and ink key control device that solve the problems encountered in the past when the density resulting from color matching is controlled as a density target. It was.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an ink key control device embodying the present invention.
FIG. 2 is a comparison procedure between a conventional technique and the present invention, and a print quality comparison between the conventional technique and the present invention.
[Explanation of symbols]
10. ・ Printing unit 11 ・ ・ Ink unit 12 ・ ・ Indigo unit 13 ・ ・ Red unit 14 ・ ・ Yellow unit 15 ・ ・ Printing paper 20 ・ ・ Ink key control device 21 ・ ・ Calculation device 22 ・ ・ Measurement camera 23 ・ ・Cable 30 ... Procedure 1 of conventional method 31 ... Color 32 to be controlled ... Work to predict target density 33 ... Work to input target value 34 ... Work to start control.
40 ·· Implementation procedure 41 of Conventional Method 2 · · Color 42 to be controlled · · Color matching operation 43 · · Determining the obtained density as a target concentration 44 · · Target value input 45 · · Work to start control 50 .. Implementation procedure 51 of the present invention .. Color 52 to be controlled .. Work 53 to predict target density .. Work to input target value 54 .. Work to start black control 55. • Color 56 to be controlled • Work 57 to perform color matching • Work 58 to determine the obtained density as a target density • Work to enter a target 59 • Work to start control

Claims (6)

In a method for setting a density target that is used for offset printing using inks of at least four colors of black, indigo, red, and yellow, and manages the density of printed matter on the paper surface,
For black, set the density target predicted before printing as a density target,
For at least three colors of indigo, red and yellow, the density target of the printed matter is characterized in that the density of each color is set as the density target for each color based on the result of color matching after the start of printing. Setting method. Using the density of the solid portion of each color as the density target of each color;
The method of setting a density target for a printed matter according to claim 1. Adjusting the ink key for each color based on the density target for each color obtained by the method for setting the density target for printed matter according to claim 1;
A method for managing the density of printed matter. In the density target setting device for printed matter, which is used for offset printing using ink of at least four colors, black, indigo, red, and yellow, and sets a density target for managing the density on the paper surface of the printed matter,
Black density target input means for inputting a black density target predicted before printing ;
A measuring means for measuring the density of indigo, red and yellow on the printed paper for at least three colors of indigo, red and yellow;
Density target input means such as indigo red and yellow for inputting the density target of each color based on the density data of each color of at least three colors obtained using the measuring means;
An apparatus for setting a density target for printed matter, comprising the above. An apparatus for setting a density target for printed matter according to claim 4,
Ink key adjustment control means for controlling the adjustment of the ink key of each color based on the density target of each color set by the setting device;
A printed matter density management apparatus comprising the above.   An offset printing machine comprising the density management device for printed matter according to claim 5.

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