JPH1170636A - Method and apparatus for early stabilizing hue - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of papers (printing papers) required in trial printing for hue matching to reduce spoilage to a large extent, to always adjust a hue regardless of a skillful degree of an operator and to shorten a time required in hue matching. SOLUTION: In a method for early stabilizing a hue by regulating an ink amt. in the initial printing of a printing press, the printed surface of printed matter subjected to initial printing is measured by a spectrometer 4 and a difference between the obtained measured value and a preset reference value 18 calculated and an adjusting control parameter is operated from the correlation between this difference and an ink amt. or a ink scraping amt. and ink supply or ink scraping is performed based on the adjusting control parameter being the operation result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for early stabilizing the color tone of a printed material in a sheet-fed printing press, and more particularly, to stabilizing the color tone in a sheet-fed printing press at an early stage. And a control device for controlling the ink density for the same.

[0002]

2. Description of the Related Art Heretofore, the color tone of a printed material in a sheet-fed printing press has been performed by adjusting an ink feeding amount at an ink supply source. The work of adjusting the color tone in accordance with the ink recall amount is, in the case of a large image area (image area ratio of 30% or more), 150 to 150 hours until an appropriate color tone is obtained.
About 300 test prints were required. In the case of a small image area (image area ratio of less than 30%), about 300 to 1000 test prints are required until an appropriate color tone is obtained.

[0003] The difference in the number of test prints due to the difference in the image ratio (the number of test prints when the image ratio is low compared to when the image ratio is high) is due to the ink response of the printing press. Is different. In other words, when the image ratio is high, the amount of ink transferred to the test printing paper is large, and it is possible to quickly respond to the change in the ink density at the ink source, whereas when the image ratio is low, Since the amount of ink transferred to the test printing paper is smaller than in the case of the high image coverage described above, the excess ink on the ink roller is consumed, and the ink density at the ink source is reflected on the paper. This is because more trial printing is required in the case of a high image coverage.

Therefore, in order to reduce the number of sheets required for the above-mentioned test printing in the case of a low image coverage, conventionally, when the ink density is insufficient, the ink roller 31 shown in FIG. When the ink concentration is too high, the ink roller (ink forming roller) 3 shown in FIG.
3, a paper 34 was wound around, and excess ink was removed from the inking roller 33 with the paper 34. Such color adjustment is performed every time the printing operation is started, and even when the image ratio of the plate after the plate change is different from the image ratio of the plate before the plate change, the color adjustment as described above is performed. Was to do. In FIG. 8, 35 is an ink fountain,
36 is an ink key and 37 is a plate cylinder.

[0005]

However, as described above, the operation of supplying ink to the ink roller 31 by the spatula 32 and wrapping the paper 34 around the ink roller 33 to remove excess ink requires a great deal of labor. At the same time, since the amount of ink supplied by the spatula 32 and the amount of ink removed by the paper 34 depend exclusively on the intuition and experience (skill) of the operator, the time required to obtain an appropriate color tone varies greatly depending on the operator. In reality, it is also causing problems.

The present invention has been made in view of such circumstances, and has as its object to reduce the number of sheets (printing sheets) required for trial printing for color adjustment and greatly reduce the number of waste sheets. Color tone early stabilization method and apparatus capable of always making good adjustment of color tone irrespective of the skill level of the operator, and shortening the time required for color tone adjustment Is to provide.

[0007]

In order to achieve the above-mentioned object, the present invention provides a method for early stabilization of a color tone for stabilizing the color tone by adjusting the amount of ink during initial printing of a printing press. In, the printing surface of the printed matter subjected to the initial printing is measured with a spectrometer, the difference between the measurement value obtained thereby and a preset reference value is obtained, and this difference and the ink supply amount or the ink scraping amount are calculated. The adjustment control parameter is calculated from the correlation, and ink supply and / or ink scraping is performed based on the adjustment control parameter resulting from the calculation.

Further, in the present invention, the printing press is set to a low-speed idling state during the color tone adjustment control based on the adjustment control parameters so that printing on printing paper is not performed.

Further, according to the present invention, there is provided a color tone early stabilizing apparatus for stabilizing color tone by adjusting the amount of ink at the time of initial printing of a printing press, and (a) measuring print density on a printing paper surface. A print density measuring device, (b) a color tone management device for obtaining a density difference between the print density measured by the measuring device and a reference density, and (c) a correlation between the density difference and an ink supply amount or an ink scraping amount. An arithmetic unit for calculating adjustment control parameters relating to the ink key opening, the ink source roller rotation speed, the ink feeding speed, and the like,
And (d) an ink supply device and an ink scraper, each of which is controlled based on the adjustment control parameter calculated by the calculator.

Further, in the present invention, a spectrometer is used as a print density measuring device for printing paper.

Further, in the present invention, an ink scraping doctor is provided on an ink forming roller which comes into contact with a plate cylinder of a printing press or an ink roller next to the roller.

Further, in the present invention, the ink doctors for scraping the ink are installed in correspondence with the ink rollers at a plurality of positions.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a sheet-fed printing press 2 equipped with an early color tone stabilizing device 1 according to a first embodiment of the present invention, and this device 1 implements the early color tone stabilizing method of the present invention. Is what you do.

As shown in FIG. 1, the early color tone stabilizing device 1 of the present embodiment is obtained by a spectrometer 4 for measuring the ink density on the printing paper 3 and the measurement by the spectrometer 4. A color tone management device 5 for obtaining an ink density difference δD (= printed paper density−reference density) between the measured solid density (printed paper density) and a preset reference density determined by proof printing and the like; An arithmetic unit 6 for calculating an adjustment control parameter based on the difference δD;
And an ink adjusting device 7 to which adjustment control parameters sent from the printer are input. Further, the above-described ink adjusting device 7 includes an ink supply device 11 for controlling the opening degree of the ink key 8, the number of rotations (rotational speed) of the ink source roller 9, the number of ink calls, and the like.
And an ink scraping device 13 for controlling the amount of ink scraped by the ink. In addition, the ink supply device 1
1 does not need to change all the mechanisms to be controlled, and any one of them may be selected and controlled.

FIG. 2 shows a correlation between the ink density difference δD, the ink scraping amount and the ink supply amount. As can be seen from FIG. 2, as the ink density difference δD increases, the amount of ink scraped, that is, the number of rotations of the ink roller that scrapes the ink increases, and as the ink density difference δD becomes negative, the amount of ink supply increases. I try to increase.

The specific operation will be described below with reference to a flowchart of an example of the control shown in FIG. First, the spectrometer 4 measures the density of the printing paper surface obtained by performing printing with the ink key opening set based on the value measured by a separately provided printing screen area ratio meter. The measurement value obtained in this way is compared with a reference density (reference value) obtained from a proof print or the like preset in the color tone management device 5, and an ink density difference δD is obtained from the comparison result. When the ink density difference δD is within the allowable set value, it is determined that the ink density is appropriate, and the adjustment and control by the early color tone stabilizing device 1 is terminated, and normal printing is performed.

On the other hand, when the ink density difference δD deviates from the allowable set value, the printing press 2 is set in the idling state (state in which printing is not performed), and the adjustment and control mode by the early color tone stabilizing device 1 is set. You. In the adjustment and control at this time, the control operation is divided depending on whether the density difference is positive or negative. That is, when the ink density difference δD is positive, the ink key 8 is too high because the ink density is too high.
Of the ink roller 14 (FIG. 1)
The excess ink that has reached (see) is scraped off by the ink doctor 12. The ink supply (ink feeding) is started after a delay of the calculated time, and the idling is stopped when the ink film thickness on the ink roller group reaches a rotation speed corresponding to the changed ink key opening.

When the ink density difference δD is negative, the ink density is too low, so the ink supply amount related to the opening of the ink key 8, the ink feeding speed, the rotation speed of the ink source roller 9, and the like. Is obtained from the correlation shown in FIG. 2, ink is called at the required ink key opening, the ink supply roller 9 is rotated to supply an insufficient amount of ink to the ink roller group, and the ink doctor 12 also performs ink scraping. The printing machine 2 is operated to end the idling of the printing press 2 and perform actual printing. The ink density of the printing paper obtained here is measured by the spectrometer 4, and the above control is repeated until the ink density difference δD falls within the allowable set value. As described above, by idling the printing press 2 while performing the color tone adjustment control, it is possible to eliminate the waste paper that was conventionally required during that time, and to greatly reduce the waste paper.

In addition, by adjusting the ink key opening so that the ink density difference δD falls within the allowable set value, the color tone can be adjusted to be constant regardless of the skill level of the operator. it can.

Further, by adjusting and controlling the amount of ink based on the number of ink calls or the number of times of ink scraping using the ink density difference δD as a parameter, a change in the amount of ink in accordance with the degree of opening of the ink key can be made quickly. Plate cylinder 1
5 (see FIG. 1). Therefore, the time required for color adjustment can be greatly reduced, and when the image rate is low (low image quality)
, The accuracy of color matching can be improved.

By the way, as a print density measuring device, a densitometer may be used when only the determined colors of sumi (black), eye (indigo), red (red), and yellow (yellow) are targeted. When printing a special color, it is preferable to use a spectrometer capable of measuring all colors with high accuracy.

FIG. 4 shows a sheet-fed printing press 17 provided with a color tone early stabilizing device 16 according to a second embodiment of the present invention. In FIG. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 4, the color tone early stabilizing device 16 of the present embodiment is configured such that the ink doctor 12 moves the ink doctor 12 closer to the ink cylinder 18 than the case of the first embodiment. This is to be installed in correspondence with the next ink roller (the ink roller next to the ink applying roller 19).

As shown in FIG. 5, the ink film thickness on the ink roller 18 gradually decreases from the ink source roller 9 to the plate cylinder 15 due to the transfer of ink between the ink rollers, and is uniform and appropriate. An appropriate ink film thickness is formed on the plate cylinder 15. However, in the conventional method for stabilizing the color tone at an early stage, ink is supplied onto the ink source roller 9 after cleaning the roller, the sheet-fed printing press 16 is idled, and then printing is started through the printing paper. As for the thickness, since the ink remaining in the ink roller group is not consumed (of course not supplied), the ink roller runs idle, so that the ink film thickness on all the rollers is the same, as shown in FIG. From the start of printing to the target value, that is, the target ink film thickness,
The change in the ink film thickness indicated by hatching α in FIG. 5 is necessary.

Therefore, in the present embodiment, the ink doctor 12 is installed on an ink roller 18 as close as possible to the plate cylinder 15 (an ink roller on the upstream side of the ink application roller 19 that comes into contact with the plate cylinder 15), and roller cleaning is performed. Thereafter, the ink scraping device 13 is supplied while supplying the calculated target ink amount.
When the ink is scraped off, the ink film thickness becomes as shown by the solid line β in FIG.

In this state, when printing is started through the printing paper, a predetermined target ink film thickness is obtained with a change in the ink film thickness as indicated by hatching γ in FIG. It can be seen that there is a difference in the amount of change. This difference is the difference in the amount of waste paper, and the difference in the print preparation time. That is, in the case of the present embodiment, the number of damaged sheets is reduced and the print preparation time is shortened as compared with the conventional case due to the difference described above.

More specifically, conventionally, the ink film thickness on the ink roller immediately after the end of the trial printing is as shown by "A" in FIG. 5, and the ink density is too high to meet the next target "B". When idle, the idle rotation after proof printing and the idle rotation before loading the cylinder for the next printing continue without idle,
The ink film thickness on the ink roller is equalized and becomes as shown by "C" in FIG. When printing is started, the ink film thickness on the plate cylinder 15 is large, and printing that is too dark is performed until "D" shown in FIG. 5 is eliminated, resulting in paper loss. On the other hand, in the case of the second embodiment of the present invention, when the ink having the next target density is supplied while scraping off the ink film thickness “A” immediately after the end of the trial printing with the ink doctor 12, the ink is Since ink is supplied from the ink source roller 9 at a new ink key opening while being consumed, the ink film thickness on the ink roller is represented by β in FIG. The ink film thickness “E” indicated by β differs from the new target ink film thickness “F” only by the γ portion indicated by hatching in FIG. 5, so that when printing starts, the γ portion is immediately eliminated by the cancellation of the γ portion. And the paper loss is greatly reduced.

FIG. 6 shows a sheet-fed printing press 21 provided with a color tone early stabilizing device 20 according to a third embodiment of the present invention. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the early color tone stabilizing device 20 in this embodiment is the same as the device 16 in the second embodiment.
In addition, the ink doctor 23 is installed on the ink roller 22 near the ink source.

In this early color tone stabilizing device 20,
As shown in FIG. 7, when there is too much ink during the trial printing,
That is, when the ink density difference δD is extremely large, the ink film thickness can be consumed quickly by scraping the ink to reach the target ink film thickness at a plurality of locations, and the horizontal line P in FIG. , Q, the convergence to the target ink film thickness is further accelerated.

More specifically, the difference between the third embodiment of the present embodiment and the above-described second embodiment is that an ink doctor 23 for scraping ink is added. The effect is as follows.
That is, when the ink film thickness is too large, the doctor blade is calculated based on the amount of ink on the ink roller in order to speed up the idle rotation to the state "c" in FIG. 23 determines the scraping time. As a result, the state of “c” is quickly reached. The effect after the state of “c” is obtained is the same as that of the second embodiment described above.

Although the embodiments of the present invention have been described, the present invention is not limited to these embodiments, and various modifications and changes can be made based on the technical idea of the present invention. For example, the ink rollers to be used for scraping the ink with the ink doctor are not limited to the ink rollers 14, 18, and 22 in the above-described embodiment, and may be other ink rollers such as the ink forming roller 19 as necessary. The ink doctors may be arranged correspondingly to scrape the ink. Further, the number of ink rollers for scraping the ink by the ink doctor can be changed as required.

[0034]

As described above, in the color tone early stabilization method according to the first aspect of the present invention, the printing surface of the printed material on which the initial printing has been performed is measured by the spectrometer, and the measured value obtained by the measurement is obtained. And a reference value set in advance, an adjustment control parameter is calculated from a correlation between the difference and the ink supply amount or the ink scraping amount, and the ink supply and / or Since the ink is scraped, the time required for the ink film thickness on the ink roller to reach the target ink film thickness can be shortened. It is possible to reduce the number of printing papers required for color tone adjustment) and to reduce the amount of waste paper.

Further, according to the present invention, while the color tone adjustment control is being performed based on the adjustment control parameter (that is, while the ink supply or the ink scraping for the color tone adjustment is being performed). Is to keep the printing machine idle and not to print on the printing paper, so it is possible to completely eliminate the waste paper that was required during that time, and to greatly reduce the waste paper Can be.

Further, according to the color tone early stabilizing device according to the present invention, the following effects can be obtained. That is, it is possible to adjust the ink key opening so that the density difference (ink density difference) between the print density measured by the measuring instrument and the reference density falls within the allowable set value. By adopting, the color tone adjustment work can always be performed satisfactorily regardless of the skill level of the operator. Further, by calculating and controlling the ink amount by calculating the number of ink calls or the number of ink scraping operations using the density difference as a parameter, the change in the ink amount due to the ink key opening can reduce the ink density on the plate cylinder. And the time required for color matching can be greatly reduced. In addition, when the stroke rate is low (low stroke)
, The accuracy of color matching can also be improved.

Further, according to the color tone early stabilizing device according to the present invention, since a spectrometer is used as a print density measuring device for printing paper, all colors can be measured with high accuracy. Therefore, the color tone adjustment for all colors can be performed with high accuracy.

Further, according to the color tone early stabilizing device according to the present invention, an ink forming roller which comes into contact with a plate cylinder of a printing press or an ink roller next to this roller (an ink roller close to the plate cylinder) )), An ink doctor for ink scraping is provided, and the ink is scraped off by the ink scraping device while supplying the calculated target ink amount, so that the ink film thickness on the ink roller is similar to the operating state. . Therefore, when printing is started, the ink film thickness on the plate cylinder reaches the target ink film thickness at an early point. This is advantageous for reducing waste paper and shortening the color tone adjustment time (print preparation time).

According to the color tone early stabilizing device according to the present invention, since the ink doctors for scraping the ink are provided corresponding to the plurality of ink rollers, respectively, the difference in ink density is particularly small. When it is extremely large, the ink film thickness can be quickly consumed, and the convergence to the target ink film thickness can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a sheet-fed printing press provided with a color tone early stabilization device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a correlation between an ink density difference and the number of ink calls and the number of ink scrapings.

FIG. 3 is a flowchart illustrating a control flow of an early color tone stabilization method performed by the early color tone stabilization device according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a sheet-fed printing press provided with a color tone early stabilization device according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a change in the ink film thickness on the ink roller in the related art and a change in the ink film thickness on the ink roller in the second embodiment of the present invention.

FIG. 6 is a configuration diagram of a sheet-fed printing press provided with a color tone early stabilization device according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a change in the ink film thickness on the ink roller according to the related art and a change in the ink film thickness on the ink roller according to the third embodiment of the present invention.

FIG. 8 is a configuration diagram of a sheet-fed printing press provided with a conventional color tone early stabilization device.

[Explanation of symbols]

 1,16,20 Color tone early stabilization device 2,17,21 Sheet-fed printing press 3 Printing paper 4 Spectrometer 5 Color tone management device 6 Arithmetic circuit 7 Ink adjustment device 8 Ink key 9 Ink source roller 10 Ink roller 11 Ink Supply device 12, 23 Ink doctor 13 Ink scraping device 14, 18, 22 Ink roller 15 Plate cylinder 19 Ink application roller δD Ink density difference

Claims (6)

[Claims] 1. A method for stabilizing a color tone by adjusting an amount of ink at the time of initial printing of a printing press, wherein a printing surface of a printed material subjected to the initial printing is measured by a spectrometer. Then, a difference between the obtained measurement value and a preset reference value is obtained, and an adjustment control parameter is calculated from a correlation between the difference and the ink supply amount or the ink scraping amount, and the adjustment control of the calculation result is performed. A color tone early stabilization method, wherein ink supply and / or ink scraping is performed based on parameters. 2. The printing apparatus according to claim 1, wherein the printing machine is idled while the color tone adjustment control is being performed based on the adjustment control parameters, and printing is not performed on printing paper. Color tone early stabilization method. 3. A color tone early stabilizing device for stabilizing color tone by adjusting the amount of ink at the time of initial printing of a printing press, wherein: (a) a print density measuring device for measuring a print density on a printing paper surface; (B) a color tone management device for determining a density difference between a print density measured by the measuring instrument and a reference density;
(C) an arithmetic unit for calculating adjustment control parameters relating to the ink key opening, the ink source roller rotation speed, the ink feeding speed, etc. from the correlation between the density difference and the ink supply amount or the ink scraping amount; A color tone early stabilization characterized by comprising an ink supply device and an ink scraper, each of which is operated and controlled based on the adjustment control parameters calculated by the calculator. Device. 4. The color tone early stabilizing apparatus according to claim 3, wherein the print density measuring device on the printing paper is a spectrometer. 5. An ink wiping roller which comes into contact with a plate cylinder of a printing press or an ink doctor next to this roller provided with an ink doctor for scraping ink.
Or the color tone early stabilizing device according to 4. 6. The color tone early stabilizing device according to claim 3, wherein the ink scraping doctors are provided corresponding to a plurality of ink rollers, respectively.