JPH1158663A - Device for pattern-area ratio adjusting mark allocation and offset printing plate manufactured by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excess dampening water state of a small area ratio part, and bring balancing condition of ink and dampening water near appropriate value for reducing surface water by calculating correction value to make the area ratio differences between divided sections to a minimum for imparting correction. SOLUTION: CPU is at least provided with a dividing means 1, which divides data by ink key width of a printer; a calculating means 2, which calculates area ratios of ink impressed parts based on the divided data divided by the dividing means 1; and a correction amount calculating means 3, which compares the area ratios of each divided part calculated by the calculating means 2 for extracting a maximum area ratio and a minimum area ratio, and calculates correction amounts for making the area ratios of each divided part to a minimum. An allocating means 4 can be provided for allocating the ink impressed parts corresponding to the correction amounts calculated by the correction amount calculating means 3 outside of the finished dimensions of each divided part as pattern area ratio adjusting marks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for presetting the ink keys by calculating an area ratio of an ink-coated portion for each ink key width size in a printing width direction in offset printing. The present invention relates to a mark area adjusting device for adjusting a pattern area ratio for uniforming the area ratio of a meat portion, adjusting the balance with a dampening solution and performing good printing, and an offset printing plate manufactured using the same.

[0002]

2. Description of the Related Art A conventional offset printing press includes an ink fountain 30 for temporarily storing ink and a watercraft 20 for storing dampening water, as shown in FIG. The ink and the dampening solution reach the printing plate 29 via a plurality of rollers on different routes and merge. The dampening solution passes through the water roller 20 and a plurality of rollers from the watercraft 20 to form a uniform and thin water film on the roller 22 in order to prevent ink from reaching the non-image area of the plate surface 29. Apply dampening solution to the entire plate surface so that it can be formed on the surface.

On the other hand, the ink is formed by an ink key 31 in an ink fountain 30 such as a doctor (a thin plate-shaped thing for scraping off the ink on a surplus printing plate of a gravure printing press) and an ink source roller 32. By adjusting the gap, the amount of ink transferred to the entire printing paper surface according to the picture to be printed is adjusted. That is,
The ink keys 31 are arranged like doctors, which are divided at regular intervals in the roller axis direction of the ink source roller 32 and are arranged regularly.

Each time a picture to be printed is different, the gap between the ink source roller 32 and the ink key 31 can be arranged differently in the roller axis direction. FIG. 8 schematically shows this state. FIG. 8 shows an example in which the number of ink keys 31 is divided into four. (In an actual printing press, it is composed of 20 to 30 divided ink keys). Regarding the distribution of the ink consumption of the picture to be printed, it is easy to understand that it is considered that a picture in which the part consumes a large amount of ink and the part in which the ink consumption decreases is printed.

The amount of ink applied to rollers 23, 24, 25, and 26 for applying ink to plate surface 29 can be partially adjusted according to the number of ink keys 31 and the width of ink keys 31 in the axial direction. it can. On the other hand, the dampening solution has a constant water film thickness on the plate surface 29 in the roller axis direction. As can be seen from the roller configuration of the printing press, the ink and the fountain solution are applied to the inking rollers 23, 24, 25, 26 and the shaking roller 2 near the plate surface.
On 7 and 28, printing is performed in a state where the ink and the fountain solution are mixed.

[0006] While the ink film thickness differs in the roller axis direction, the fountain solution has a constant water film thickness.
Considering the mixing ratio of the ink and the dampening solution, the water content value on the ink roller naturally differs in some parts.
In actual printing, since the ink itself absorbs the dampening solution, the thicker the ink film on the inking roller, the more the dampening solution is required.

In the portion where the ink film thickness is the thickest, the ink itself absorbs more dampening water than in the portion, so that sufficient dampening water is not supplied to the plate surface 29. Ink adheres to the non-image area and causes background contamination. From the above, the supply amount of the dampening solution is adjusted so as to be an appropriate amount in the portion where the ink film thickness is the thickest. In other words, in other places, the relative proportions of the ink amount and the dampening solution become excessive.

Under the printing conditions shown in FIG. 8, continuous printing was performed so that the state of the ink and the dampening solution in the thickest portion of the ink film was constant. FIG. 9 shows the result. It can be seen that the proportion of dampening water becomes relatively large, and that the amount of ink transferred to the paper decreases in the order of the copies over time. This is because the ink itself can not absorb the dampening water, it is formed as surface water on the ink surface, and the water on the ink surface is transferred during the process of transferring the ink from the ink roller to the plate surface, blanket, and paper surface. It is considered that stable ink transfer could not be reproduced by inhibiting ink transfer.

In addition, since the transfer of the ink is stagnant, and the ink containing excessive dampening solution tends to accumulate on the ink roller, the transfer state of the ink further decreases with time. Resulting in. Such a state is different depending on the type of the picture, but the tendency is that it occurs except for printing conditions in which the ink film thickness is formed to be constant in the axial direction on the ink roller. This instability factor depends on the intuition and experience of the printing press operator, but if fine adjustments cannot be made, a wrong decision may cause a serious trouble.

[0010]

According to the data shown in FIG.
In the position, the balance state of the ink and the dampening solution is relatively appropriate, and at the same time, the surface water is low.
It was considered that when the fountain solution became excessive, the ink could no longer hold the fountain solution and the surface water increased. That is, as described above, the dampening solution supply method is substantially constant in the printing width direction, whereas the ink supply method is, as shown in FIG. The supply amount (ink film thickness) can be adjusted.

The ink supply amount is determined to be an appropriate value corresponding to the pattern of the printed matter, and the ink film thickness on the ink rollers 23, 24, 25 and 26 where the ink and the dampening solution in FIG. Does not form a uniform film thickness. In the actual printing, depending on the pattern to be printed, in the printing width direction, FIG.
It is considered that such a phenomenon occurs with some differences.

According to the present invention, there is provided a method of presetting an ink key by calculating an area ratio of an ink-filled portion for each ink key width size in a printing width direction in offset printing. It is an object of the present invention to provide a mark area adjusting device for adjusting a pattern area ratio for uniformizing the ratio, adjusting the balance with a dampening solution and performing good printing, and an offset printing plate manufactured using the same.

[0013]

According to a first aspect of the present invention, in offset printing, data for producing a printing plate produced by an image processing apparatus having a computer is rearranged according to the imposition involved in the printing, and printing is performed. A dividing unit that divides data for each ink key width size of a printing press, a calculating unit that calculates an area ratio of an ink-inlaid portion from the divided data divided by the dividing unit, and each of the divisions calculated by the calculating unit. Printing means for comparing the area ratio of each copy, extracting a maximum area ratio and a minimum area ratio, and calculating a correction amount so as to minimize the area ratio difference between the divided sections; A mark layout device for adjusting a pattern area ratio, wherein plate data is prepared by correcting an ink deposition area ratio value for each ink key width size in the width direction. The correction amount is calculated so that the difference between the area ratios between the divided portions is minimized, and the correction is applied, thereby preventing a portion having a small area ratio from being excessively dampened with water and dampening with ink and dampening. The balance state of water approaches an appropriate value, and surface water decreases.

According to a second aspect of the present invention, there is provided a means for allocating an ink-coated portion corresponding to the correction amount calculated by the correction amount calculating means as a pattern area ratio adjustment mark outside the finished dimensions of each of the divided portions. 2. The method according to claim 1, further comprising:
It is a mark layout device for adjusting the picture area ratio described in the above. 2. A correction amount is calculated such that an area ratio difference between the divided portions is minimized, and an ink-filled portion (a pattern area ratio adjusting mark) for correction is provided outside the finished dimensions of each divided portion. ) Is provided, so that the area ratio difference between the divided portions can be easily minimized.

According to a third aspect of the present invention, there is provided a method of using the mark area adjusting device for adjusting a pattern area ratio according to the first or second aspect, wherein the ink for each ink key width size in the printing width direction is provided in addition to the finished dimensions of the offset printing plate. The offset printing plate is characterized in that a mark for adjusting the pattern area ratio is provided from the plate data obtained by correcting the inlaid area ratio value. By using the mark area allocation device for adjusting the pattern area ratio of the present invention, by outputting to an offset printing plate and printing on the offset printing plate,
Conventionally, a portion having a small area ratio is prevented from being in a dampening water excess state, the balance state of the ink and the dampening water approaches an appropriate value, and the surface water is reduced.

[0016]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram of a picture area ratio adjusting mark allocating apparatus according to an embodiment of the present invention. C
A dividing unit 1 for dividing data into each PU for each ink key width size of a printing press, a calculating unit 2 for calculating an area ratio of an ink-inlaid portion from the divided data divided by the dividing unit 1, A correction amount for extracting the maximum area ratio and the minimum area ratio by comparing the area ratios of the divided portions calculated by the means 2 and calculating the correction amount so that the area ratio between the divided portions is minimized. Calculation means 3 is provided at least. Further, an ink-inlaid portion corresponding to the correction amount calculated by the correction amount calculation means 3 is used as a pattern area ratio adjustment mark.
Means 4 for allocating outside of the finished dimensions of each of the divided portions may be provided.

The CPU has an input device 6 for inputting data from the image processing device, a storage device 7 for storing the data and smoothly performing processing such as arithmetic processing, and the like, for each ink key width size in the printing width direction. The printing plate data obtained by correcting the ink deposition area ratio is output on a transparent film, and an image setter 8 serving as a positive film, an output machine 9 for outputting the printing plate data directly on a printing plate material, and a CRT A monitor 5 for displaying a processing state is connected. The peripheral devices described above are not particularly limited, and may be used as needed. For example, a DDCP (Digital Color Proofing Machine) can be used to confirm tone reproduction, appearance, and the like. In addition to batch processing of a magnetic disk, a magneto-optical disk, or the like, the input device can also be input online from an image processing device.

FIG. 2 illustrates the configuration of the offset printing plate of the present invention. A total plate size 10, a printable size 12, and a finished size 11 are shown.
In addition, the ink key width 16 is schematically shown as being divided into four.
The hatched portion is a margin 14 that is cut after printing. In the present invention, an ink-filled portion (a mark for adjusting a picture area) corresponding to the correction amount is provided in the margin 14 for each ink key width 16.

FIG. 3 shows an embodiment of the offset printing plate of the present invention. This is an offset printing plate manufactured under the conditions as shown in the schematic explanatory view of FIG. 8, and the position of the ink key width 16 corresponds to in each figure. The ink film thickness is the thickest and the thinnest. In inverse proportion, on the offset printing plate,
A mark 13 for adjusting the pattern area ratio in the margin 14 is provided. The mark 13 for adjusting the pattern area ratio is solid (100
%), The area changes, but the shape, area ratio, etc. are arbitrary.

FIG. 4 shows another embodiment of the offset printing plate of the present invention. The area ratio is changed without changing the area of the margin 14. For example, 100
%, 60%, 30%, and 0%.

FIG. 5 is an explanatory diagram for explaining states before and after the correction according to the present invention. Ink roller 15
Assuming that the thickness of the ink 17 for each of the upper ink key widths 16 is the upper figure (before correction), the correction amount is determined so that the area ratio difference between the divided portions is minimized. Since a portion (a mark for adjusting the pattern area ratio) is provided, the amount of used ink substantially increases, and the required ink film thickness becomes substantially equal.

[0022]

An embodiment will be described below with reference to the drawings. <Embodiment 1> A description will be given based on FIG. FIG. 6 is a flowchart showing an embodiment of a picture area ratio adjustment mark allocating apparatus according to the present invention. First, since the number and size of the ink keys differ depending on the manufacturer and type of the printing press to be printed, the target printing press is selected from the data registered in advance. By this selection, a finished area value and a printable margin area value for each ink key are calculated. Next, from the pattern data on which imposition and the like to be finally printed are performed, each color (Y,
The image area ratio of the ink key number for each of M, C, K) is calculated.

The maximum area ratio and minimum area ratio are extracted by comparing the area ratio values (printing width direction) of each color ink key.
Since the area ratio values of other ink key numbers are within the range of this difference, it is necessary to minimize the difference between the maximum value and the minimum value so that the ink film thickness on the ink roller becomes uniform. become. Therefore, the size of the mark in the printable margin is adjusted to the pattern area ratio within the finished size, and correction is performed so that the entire pattern area ratio value approximates the maximum pattern area ratio value. At this stage, the correction of the optimal pattern area ratio is completed by using the printable margin area as much as possible, and finally, the presetting of the ink key opening of the printing press is performed. The pattern area ratio value was converted into ink key opening data in the format, and the data was passed to the printing press to complete the preset. Printing was performed on the coated paper with a sheet-fed offset printing machine (four-color printing machine), and the printing result was checked over time. Good results were obtained without a decrease in reflection density.

<Example 2> An offset printing plate as schematically shown in FIG. 3 was obtained and printed by the same machine as in Example 1. The results were good.

[0025]

According to the first aspect of the present invention, the correction amount is calculated so that the area ratio difference between the divided portions is minimized, and the correction is performed. This prevents the ink from becoming wet and the balance between the ink and the dampening solution approaches an appropriate value, and the surface water decreases, so that stable printing can be performed even over time.

According to a second aspect of the present invention, in the first aspect, a correction amount is calculated so that an area ratio difference between the divided portions is minimized.
Means for allocating an ink-filled portion (a mark for adjusting the pattern area ratio) for correction outside the finished dimensions of each divided portion is provided, so that the difference in the area ratio between each divided portion can be easily minimized. Enabled.

According to a third aspect of the present invention, an image is output to an offset printing plate using the picture area ratio adjusting mark allocating device of the present invention, and the offset printing plate is used for printing. To prevent excess water, and the balance between ink and dampening water approaches an appropriate value.
An offset printing plate with reduced surface water can be provided.

[0028]

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a picture area ratio adjusting mark allocating apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a configuration of an offset printing plate of the present invention.

FIG. 3 is an explanatory view showing one embodiment of the offset printing plate of the present invention.

FIG. 4 is an explanatory view showing another embodiment of the offset printing plate of the present invention.

FIG. 5 is an explanatory diagram showing a distribution (before and after correction) of an ink film thickness of each ink key on an ink forming roller.

FIG. 6 is a diagram showing a flowchart of an embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a roller arrangement of the printing press.

FIG. 8 is an explanatory diagram showing a difference between an ink supply method and a dampening solution supply method in a printing width direction.

FIG. 9 is an explanatory diagram showing a change in paper surface density due to a difference in balance between ink and dampening solution.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Division means 2 ... Calculation means 3 ... Correction amount calculation means 4
... (means for assigning) 5 ... monitor 6 ... input device 7
... storage device 8 ... imagesetter 9 ... output machine 10 ...
All plate sizes 11 ... Finished size 12 ... Printable size 13 ... Mark for adjusting the pattern area ratio 14 ... Margin 1
5 ... Ink roller 16 ... Ink key width 17 ...
Ink 20 ... water boat 21 ... water source roller 22 ... water application roller 23 ... first ink application roller 24 ... second ink application roller 25 ... third ink application roller 26 ... fourth ink application roller 27, 28 ... swing roller 29 ... plate surface 30 ... ink fountain 31 ... ink key

Claims (3)

[Claims] 1. In offset printing, data for producing a printing plate created by an image processing apparatus equipped with a computer is rearranged according to imposition for printing, and the data is sorted for each ink key width size of a printing press to be printed. Dividing means for dividing, calculating means for calculating the area ratio of the ink-inlaid portion from the divided data divided by the dividing means, and comparing the area ratio of each divided part calculated by the calculating means with the maximum area A correction amount calculating means for extracting a ratio and a minimum area ratio, and calculating a correction amount such that an area ratio difference between the divided portions is minimized. A mark layout device for adjusting a pattern area ratio, wherein the plate data is prepared by correcting the area ratio value. 2. The apparatus according to claim 1, further comprising means for allocating an ink-coated portion corresponding to the correction amount calculated by said correction amount calculating means as a pattern area ratio adjustment mark outside the finished dimensions of each of said divided portions. The mark layout device for adjusting a pattern area ratio according to claim 1. 3. An ink deposition area ratio value for each ink key width size in the printing width direction, in addition to a finished dimension of an offset printing plate, using the mark area ratio adjusting mark allocating device according to claim 1 or 2. An offset printing plate, characterized in that a mark for adjusting the pattern area ratio is provided from the printing plate data obtained by correcting the above.