JP4019458B2 - Pattern area ratio adjustment mark allocating apparatus and offset printing plate produced using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention calculates the area ratio of the ink deposit area for each ink key width size in the printing width direction in offset printing, and in the method for performing the presetting of the ink key, the area ratio of the ink deposit section of each ink key width is uniform. The present invention relates to a pattern area ratio adjusting mark assigning device for adjusting the balance with dampening water and performing good printing, and an offset printing plate produced using the same.
[0002]
[Prior art]
As shown in FIG. 7, the conventional offset printing machine has an ink fountain 30 for temporarily storing ink and a water boat 20 for storing dampening water. The ink and the fountain solution arrive at the plate surface 29 via a plurality of rollers through different routes and merge. The fountain solution passes from the water boat 20 to the water source roller 21 and a plurality of rollers so that the ink does not adhere to the non-image area of the plate surface 29, thereby forming a uniform and thin water film on the swim roller 22. Apply dampening water to the entire plate so that it can be formed on the surface.
[0003]
On the other hand, the ink adjusts the gap formed by the ink source roller 32 and the ink key 31 in the ink fountain 30 such as a doctor (thin plate-like one that scrapes off the ink on the excess plate surface of the gravure printing machine). By doing so, it is a mechanism for adjusting the amount of ink transferred to the entire printing paper surface depending on the pattern to be printed. That is, the ink keys 31 are regularly arranged in a doctor-like manner divided at regular intervals in the roller axial direction of the ink source roller 32.
[0004]
Each time the pattern 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 ink consumption of the pattern to be printed, it is considered that (1) part prints a pattern with high ink consumption and (2), (3), and (4) parts with low ink consumption. It is easy to understand.
[0005]
Ink can be partially adjusted with respect to the rollers 23, 24, 25, and 26 for applying ink to the printing plate 29 according to the number of ink keys 31 and the width of the ink key 31 in the axial direction. On the other hand, the fountain solution is adapted to have a constant water film thickness on the plate surface 29 in the roller axial direction. As can be seen from the roller configuration of the printing press, the ink and fountain solution are mixed with the ink and the fountain solution on the ink form rollers 23, 24, 25, and 26 and the swing rollers 27 and 28 near the plate surface. Is being printed.
[0006]
While the ink film thickness differs in the roller axis direction, the dampening water has a constant water film thickness, so when considering the mixing ratio of ink and dampening water, the moisture content value on the ink roller is Of course, it differs in the parts (1), (2), (3), and (4). In actual printing, since the ink itself absorbs dampening water, the thicker the ink film on the ink form roller, the more dampening water is required.
[0007]
In the portion {circle around (1)} where the ink film thickness is the thickest, the ink itself absorbs dampening water more than the portions {circle over (2)}, {circle over (3)}, {circle around (4)}, so If fountain solution is not supplied, ink will adhere to the non-image area and cause soiling. From the above, the supply amount of the fountain solution is adjusted so as to be an appropriate amount at the thickest portion of the ink film thickness. That is, the ratio of the relative ink amount and the dampening water amount becomes excessive in other places.
[0008]
Under the printing conditions shown in FIG. 8, continuous printing was performed so that the state of the ink and the dampening water in the portion {circle around (1)} having the largest ink film thickness was constant. The result is shown in FIG. It can be seen that the amount of ink transferred to the paper surface decreases with time in the order of (2), (3), and (4), where the ratio of the dampening water increases relatively. This is because the ink itself cannot absorb the dampening water and is formed as surface water on the ink surface, and the water on the ink surface is transferred in the process of ink transfer from the ink roller to the plate and blanket and to the paper surface. It is thought that the ink transfer is inhibited and the stable ink transfer cannot be reproduced.
[0009]
In addition, since the ink transfer is stagnant, the ink containing excessive fountain solution tends to accumulate on the ink roller, so that the ink transfer state further decreases with time. . Such a state has a difference depending on the type of the pattern, but the tendency is to occur except for printing conditions in which the ink film thickness is formed in a constant film thickness in the axial direction on the ink roller. This instability factor depends on the intuition and experience of the operator of the printing press. However, if fine adjustment is not possible, it will be the basis of a big trouble if the judgment is wrong.
[0010]
[Problems to be solved by the invention]
In the data of FIG. 9, at the position (1), the balance between the ink and the dampening water is relatively appropriate and at the same time the surface water is low, while the positions (2), (3), and (4) It was thought that when the dampening water was in an excessive state, the dampening water could not be held in the ink, and the surface water increased. That is, as described above, the fountain solution supply method is a substantially constant amount in the print width direction, whereas the ink supply method uses an arbitrary ink for each ink key width size as shown in FIG. Supply amount (ink film thickness) can be adjusted.
[0011]
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 water in FIG. 7 meet is uniform in the printing width direction. No film thickness is formed. Even in actual printing, it is considered that the phenomenon as shown in FIG. 9 occurs in the printing width direction depending on the pattern to be printed, although there are some differences.
[0012]
The present invention calculates the area ratio of the ink deposit area for each ink key width size in the printing width direction in offset printing, and in the method for performing the presetting of the ink key, the area ratio of the ink deposit section of each ink key width is uniform. It is an object of the present invention to provide a pattern area ratio adjusting mark allocating device for adjusting the balance with the fountain solution and performing good printing, and an offset printing plate produced using the same.
[0013]
According to the first aspect of the present invention, in offset printing, data for producing a printing plate produced by an image processing apparatus equipped with a computer is rearranged in accordance with imposition for printing, and is printed for each ink key width size of a printing press. The dividing means for dividing the data, the calculating means for calculating the area ratio of the ink-implanted portion from the divided data divided by the dividing means, and comparing the area ratio for each divided portion calculated by the calculating means extract the maximum area ratio and the minimum area ratio, a correction amount calculating means for the area index difference between the respective divided unit calculates the correction amount so as to minimize, to the correction amount calculated by the correction amount calculating means Assign the corresponding ink-implanted part as a mark for adjusting the pattern area ratio, and assign it to a blank area outside the finished dimensions at the printing direction top and bottom ends of each divided part in the printable part of the printing plate in a top-and-bottom symmetric shape. It comprises a stage, an image area ratio adjustment mark assignment apparatus characterized by creating a printing plate data plus correction inking area ratio value of the ink key for each width size of the print width direction. By calculating the correction amount so that the difference in area ratio between each divided part is minimized, and adding the correction, it is possible to prevent the area where the conventional area ratio is small from being dampened with water and dampening with ink. The balance of water approaches the appropriate value and surface water is reduced.
[0015]
The invention according to claim 2 uses the pattern area ratio adjusting mark allocating apparatus according to claim 1 to correct the ink deposit area ratio value for each ink key width size in the printing width direction outside the finished dimensions of the offset printing plate. The offset printing plate is characterized in that a pattern area ratio adjustment mark is provided from the printing plate data to which is added. Using the pattern area ratio adjusting mark allocating device of the present invention, outputting to an offset printing plate and printing with the offset printing plate prevents a portion having a small area ratio from being dampened with excess water. The balance between ink and fountain solution approaches the appropriate value and surface water is reduced.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments will be described in detail with reference to the drawings.
FIG. 1 is a functional block diagram of a pattern area ratio adjusting mark allocating device showing an embodiment of the present invention. The CPU includes a dividing unit 1 that divides data for each ink key width size of the printing machine to be printed, a calculating unit 2 that calculates an area ratio of the ink-implanted portion from the divided data divided by the dividing unit 1, and the calculation A correction amount for calculating the correction amount so as to extract the maximum area ratio and the minimum area ratio by comparing the area ratios of the respective divided portions calculated by the means 2 and to minimize the area ratio between the respective divided portions. At least a calculation means 3 is provided. Furthermore, means 4 for allocating the ink-implanted portion corresponding to the correction amount calculated by the correction amount calculation means 3 outside the finished dimensions of the respective divided portions may be provided as a pattern area ratio adjustment mark.
[0017]
The CPU includes an input device 6 for inputting data from the image processing device, a storage device 7 for storing the data and performing processing such as arithmetic processing smoothly, and ink attachment for each ink key width size in the print width direction. Printing plate data corrected for the wall area ratio is output on a transparent film, the image setter 8 is made as a positive film, the output machine 9 outputs the printing plate data directly on the printing plate, and the processing state is displayed on the CRT. A monitor 5 for display is connected.
The peripheral devices described above are not particularly limited, and may be used as necessary. For example, a DDCP (digital color proofing machine) can be used for confirmation of tone reproduction and appearance.
In addition to batch processing of magnetic disks, magneto-optical disks, etc., the input device can also be input online from an image processing device.
[0018]
FIG. 2 is a view for explaining 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. Also, the ink key width 16 is schematically shown in four divisions. The hatched portion is a margin 14 that is cut after printing. In the present invention, ink margins (pattern area adjustment marks) corresponding to the correction amount are provided for each ink key width 16 in the margin 14.
[0019]
FIG. 3 shows an embodiment of the offset printing plate of the present invention. FIG. 8 is an offset printing plate produced under the conditions shown in the schematic explanatory diagram of FIG. 8, and the positions of the ink key width 16 correspond to (1) to (4) in the respective drawings. The ink film thickness is thickest at (1), and thin at (2), (3), and (4). In inverse proportion to this, on the offset printing plate, a pattern area ratio adjustment mark 13 with a margin 14 is provided. Since the pattern area ratio adjustment mark 13 is solid (100%), the area changes, but the shape, area ratio, etc. are arbitrary.
[0020]
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, (4) is 100%, (3) is 60%, (2) is 30%, and (1) is 0%.
[0021]
FIG. 5 is an explanatory diagram for explaining the state before and after correction according to the present invention.
Assuming that the thickness of the ink 17 for each ink key width 16 on the ink form roller 15 is the upper figure (before correction), the correction amount is obtained so that the area ratio difference between each divided portion is minimized, and the finished margin is obtained. Since the ink depositing portion (the pattern area ratio adjustment mark) is provided, the amount of ink used is substantially increased and the required ink film thickness is substantially equal, so the figure below the arrow is shown.
[0022]
【Example】
Embodiments will be described below with reference to the drawings.
<Example 1>
This will be described with reference to FIG. FIG. 6 is a flowchart showing an embodiment of the pattern area ratio adjustment mark assigning apparatus of the present invention.
First, since the number and size of the ink keys differ depending on the manufacturer and type of the printing machine to be printed, the target printing machine is selected from data registered in advance. By this selection, a finished area value and a printable margin area value for each ink key are calculated. Next, the pattern area ratio of the ink key number for each color (Y, M, C, K) is calculated from the pattern data on which imposition or the like for final printing has been performed.
[0023]
The maximum area ratio and the minimum area ratio are extracted by comparing the area ratio values (printing width direction) for each color ink key. Since the area ratio values of other ink key numbers are within this range, it is necessary to make the difference between the maximum and minimum values as small as possible so that the ink film thickness on the ink roller becomes uniform. become. Therefore, the size of the mark in the printable blank portion is adjusted to the pattern area ratio within the finished size, and correction is performed so that the overall pattern area ratio value approximates the maximum pattern area ratio value. At this stage, the area of the printable margin is used to the maximum, the optimal pattern area ratio correction is completed, and finally the ink key opening of the printing press is preset, making it suitable for the printing press to be printed. The pattern area ratio value was converted into ink key opening data in the format, and the data was passed to the printer to complete the preset.
Printing on the coated paper was performed with a sheet-fed offset printing machine (four-color machine), and the printing results were checked over time, but good results were obtained without any decrease in reflection density.
[0024]
<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 result was good.
[0025]
【The invention's effect】
According to the first aspect of the present invention, the correction amount is calculated so that the difference in the area ratio between the respective divided portions is minimized, and by applying the correction, the portion with the conventional small area ratio is dampened with water. Since the balance between ink and dampening water approaches an appropriate value and surface water is reduced, stable printing can be performed over time.
[0027]
The invention of claim 2 uses the pattern area ratio adjusting mark allocating device of the present invention to output to an offset printing plate and print with the offset printing plate, so that a portion with a small area ratio in the past is dampened with excess water. It is possible to provide an offset printing plate that prevents the ink from being brought into a state, the balance state of the ink and the dampening water approaches an appropriate value, and the surface water is reduced.
[0028]
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a pattern area ratio adjusting mark allocating device 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 diagram showing an embodiment of an 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 for each ink key on an ink form roller.
FIG. 6 is a flowchart of an embodiment of the present invention.
FIG. 7 is an explanatory diagram showing a roller arrangement of a printing machine.
FIG. 8 is an explanatory diagram showing a difference between an ink supply method and a dampening water supply method in the printing width direction.
FIG. 9 is an explanatory diagram showing a change in paper surface density due to a difference in the balance of ink and dampening water.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Dividing means 2 ... Calculation means 3 ... Correction amount calculation means 4 ... (Assignment means) 5 ... Monitor 6 ... Input device 7 ... Storage device 8 ... Image setter 9 ... Output machine 10 ... Total size of plate 11 ... Finished size 12 ... Printable size 13 ... Picture area ratio adjustment mark 14 ... Margin 15 ... Ink roller 16 ... Ink key width 17 ... Ink 20 ... Water boat 21 ... Water source roller 22 ... Water roller 23 ... First ink roller 24 ... Second ink form roller 25 ... Third ink form roller 26 ... Fourth ink form roller 27, 28 ... Swing roller 29 ... Plate surface 30 ... Inkwell 31 ... Ink key

Claims (2)

In offset printing, dividing means for rearranging data for producing a printing plate created by an image processing apparatus equipped with a computer according to imposition for printing, and dividing the data for each ink key width size of the printing press The calculation means for calculating the area ratio of the ink-implanted portion from the divided data divided by the dividing means and the area ratio for each divided portion calculated by the calculation means are compared to determine the maximum area ratio and the minimum area ratio. A correction amount calculating means for calculating a correction amount so that an area ratio difference between the divided portions is minimized, and an ink-implanted portion corresponding to the correction amount calculated by the correction amount calculating means. as the image area ratio adjustment marks, comprising means for allocating a top-bottom symmetrical to each other the the margin outside the finished size of the printing direction vertical both end portions of each of the divided portions of the printable portion of the printing plate, printing Direction of the image area ratio adjustment mark assignment apparatus characterized by creating a printing plate data plus correction inking area ratio value for each ink key width size. From the printing plate data using the pattern area ratio adjusting mark allocating device according to claim 1 , in addition to the finished dimensions of the offset printing plate, and correcting the ink deposit area ratio value for each ink key width size in the printing width direction. An offset printing plate provided with a pattern area ratio adjustment mark.

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