Ink supply device automatically preset

The main purpose of this article is to explain the key parameters in the preset process to get the best results. There are two stages in the automatic presetting of the ink supply device: 1. Determine the area coverage, 2. Calculate the set value of the ink volume control element. For this reason, the system must clearly understand the relationship between metering and inking. In order to calculate the ink metering value, the system must take into account the press parameters, such as the lateral ink, ink backflow, and stable weather conditions that are important for good results. Although spot colors are more difficult to handle, standardization, color management, regular maintenance, and calibration of equipment components plus a stable production environment can provide good presets, and reduce preparation time and paper waste.
Ink supply device settings For a long time, the ink area screws or ink spoons were manually adjusted according to the senses. In the early 1980s, Mann Rolland introduced his own electronic plate scanner, which determined the ink supply preset based on the area coverage value. Although the system has limitations, it is indeed better than the previous one. The beginning.
Less than two decades later, automatic ink supply presets have grown considerably. More and more printers automatically determine the area coverage value directly from the print, rather than the plate scanner, even though the plate scanner has been greatly improved. This saves time and eliminates sources of error. Even so, the result is still not ideal.
In order to get a good print quickly and effectively, it is necessary to clarify some important issues. 1. What does the automatic ink supply preset mean? 2. What processes are required to reach the automatically preset value? 3, how to perform a good default feature?
The first is the calculation phase In order to understand the possibilities and limitations, to accurately calculate the preset values, the calculation phase should be carefully considered. The computing system must process the input values ​​zone by zone, first the area coverage itself, and secondly the required ink volume. However, giving only the required amount of ink is not enough for the computing system - in order to calculate the correct preset value, you must know the relationship between ink setting and ink.
Then, in two steps, the ink supply amount calculated by the ink film thickness is calculated according to the specified ink amount, and the nominal ink film thickness on the substrate is calculated. The correct setting of the ink metering elements is calculated from these nominal ink film thicknesses and area coverage. When the area coverage, the substrate characteristics, and the transfer characteristics of the printing press are known, a certain amount of ink film thickness can be obtained by adjusting a certain ink key to obtain a certain amount of printing ink.
The next task is to optimize the system must be able to generate accurate values ​​as accurately as possible from the above described relationships, so the software of the computing system is quite important. The software used by Manroland also includes technical parameters of the printer, such as the effect of transverse cross-inking or ink flow in ink fountains, which are often ignored by other systems. The best results obtained by the calculation program in the computing system still depend on the quality of the input value, so the correlation between the quantities is also a factor in the calculation.
The area coverage data obtained by the color separation scanner scans the surface of the printing plate optically and analyzes the area of ​​the image and non-graphics to obtain the area coverage data; the area coverage can also be directly obtained by the prepress processing through the CIP3 interface. Rate data, this method is now more and more widely used. After eliminating readings or sources of error from numerical database values, you need to observe the results of using the calibrated ink supply.
The use of a calibration ink supply must distinguish between the basic print colors (yellow, magenta, cyan, black) and spot colors. For printing basic colors, common standards have been defined long ago, such as FOGRA. However, many printers have developed their own standards. In order to reduce uncertainty, useful recommendations that have been used for many years are now strictly applied to the production process, but with the necessary color matching.
The nominal ink volume of a spot ink in general is usually a color value (for example, Lab), and the color management system is required to be able to correctly compensate for any difference in the production of the sample. In order to reduce the uncertainty of the color value of the spot color ink, the only compensation method is strict standardization or the use of a printability meter to measure the characteristic line. For spot colors, if the printability meter is not used or the ink supplier does not provide the relevant data, the only solution is to make a rough evaluation. In this case, the pigment of the ink and the nature of the substrate are decisive. effect.
Variables that affect ink metering On the one hand, there is a certain relationship between the area coverage of the image and the thickness of the ink film on the substrate. On the other hand, there is a direct relationship between the area coverage of the image and the adjustment value of the ink metering element. The press manufacturer must know the metering element setting adjustments, area coverage, and ink film thickness transferred to the blanket and substrate.
Table: Percentage values ​​of the deviations of the required preset results and different influencing parameters, and the best possible results

Potentially inaccurate area coverage data affecting risk improvement
EPS/CIP3 5% Using CIP3 to solve different 5% of field/mesh tones Using CIP3 at a nominal density that may not be known to print basic colors 10% Standardized spot colors, 50% of new jobs required to match spot colors with prepress, duplicate jobs 5% fluctuates due to ink price Unknown relationship between density and ink film thickness on the substrate 10% effect of lateral traversal LCS compensates for 10% of the ink flow rate in the ink fountain using LCS to compensate the dampening solution , Environmental Climate, and Printer Adjustments of 10% The best maintenance, adjustment, and environmental conditions for Manroland sheetfed offset presses are the adjustment of the ink-key and ink-inking bandwidth.

Other variables that Manroland considers are the effects of lateral ink distribution in the ink supply device.
2. When some ink keys are off, ink fountain ink flow.
3, the adjustment of the printing press. The adjustment of the ink roller and the water roller has a great influence on the ink. Checking the ink supply device regularly according to the manufacturer's technical specifications is very important for obtaining accurate ink preset results.
4. The feed of the fountain liquid also has a considerable influence on the transfer of the ink.
5. The external environment also affects the outcome - especially the climate. In particular, the temperature of the press room and the temperature and humidity of each press.
Demands for consideration of deviations For all mentioned influencing factors, we can estimate the deviations that may occur in daily production in a perfectly normal printing plant. The percentage rate given in the table “Variables affecting the automatic ink supply unit” is used as a guide. In a bad environment, or when you don't know the relationship, you must consider the preset result when the ink density exceeds the target value.
The precondition for achieving the best preset effect is the standardized parameter of the input value. Since there has been a long time standard for printing basic colors, the computing system can use these known parameters to derive the appropriate amount of ink spoon adjustment required for the required ink film thickness on the substrate.
The basic requirement for users is the standardization of printing, and more importantly, the prepress standardization. For printing itself, it is equally important to provide a good color management system, regular maintenance, calibration and adjustment of all equipment, and stable production conditions.
If all these factors are appropriate, the presetting of the automatic ink supply device will greatly save work preparation time and materials—even though spot color matching still requires more time and investment. Using CIP3 to obtain preset data can minimize processing and measurement errors and increase production efficiency.