Automatic preset possibility and limitation of ink supply device (one)
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
For a long time, the ink zone screws or ink spoons were manually adjusted and adjusted according to the sensation. The electronic plate scanners introduced in the early 1980s, when the area coverage values provided by these devices can determine the preset of the ink supply device, but usually need to take a large number of samples to check and correct the ink supply. Due to objective difficulties, these corrections take a long time and many sheets are wasted before formal printing can be performed, and the limitations of the system are discovered shortly after use.
However, twenty years later, the automatic ink supply preset has been considerably developed. More and more printers automatically determine the area coverage value directly from the prepress, instead of obtaining these values from the plate scanner, thus saving Time and eliminate the source of the error, but even so, the results are still not ideal.
In order to get a good print quickly and efficiently, some important parameters must be considered.
What does the automatic ink preset mean?
This simply illustrates the automatic adjustment of the ink volume control components in the various ink zones of the press. The goal is to make the first inspected sheet inking as close as possible to the proof or proof, saving time and material during the color matching process. There is no difference between web and sheetfed printing. The initial setting of the ink supply unit is very important for quickly achieving a good first inspection sheet, but we will not consider it here.
What processes are needed to achieve automatic presets?
Auto presets occur in two phases. The first stage is to determine the relationship between the image area and the non-image area—that is, the area coverage on each color plate. This area coverage percentage message is used in the second stage to calculate the set value of each ink zone ink key. This setting becomes the basis for the first sample.
What is the characteristic of a good preset?
How is the inking of the first sample and the proof of the sample that can be sold? The closer the visual evaluation and the measured density value are matched, the better the preset effect is, which saves time and reduces paper waste.
Calculation phase
In order to understand the possibilities and limitations, to accurately calculate the preset value, we should carefully consider the calculation phase. The calculation steps and input values that work.
The computing system must process the input values on a zone-by-region basis, starting with the area coverage itself, followed by the required amount of ink. However, only the amount of ink required is not sufficient for the computing system. In order to calculate the correct preset value, you must know the relationship between the ink setting and the ink, that is, first:
1) What kind of ink film thickness is produced by setting the ink metering element of the area coverage on the substrate?
2) Under what circumstances does the ink supply produced by the thickness of the ink film appear?
Then calculate it in two steps:
Calculate the nominal ink film thickness on the substrate according to the specified amount of ink. Figure 2 shows the relationship between ink density and ink film thickness for printing basic yellow, magenta, cyan and black colors.
The correct setting of the ink metering elements is calculated based on these nominal ink film thicknesses and area coverage. Therefore, when the area coverage, the substrate characteristics, and the transfer characteristics of the printing press are known, a certain ink film thickness is generated by a certain ink spoon adjustment, thereby obtaining a certain amount of printing ink.
What does the system need to do optimally?
The software of the computing system is quite important. For example, the effect of cross-talking ink or ink flow in the ink fountain, these parameters are often ignored by other systems. But all computing systems have one thing in common - they must produce accurate values from the interrelationships described above as accurately as possible.
The most important thing is to know what opportunities a computing system has to be as close as possible to the best expected value.
Obviously, the results obtained by the best calculation program also depend on the quality of the input values. The interrelationship between the numbers is also a factor in the calculation.
Where does the area coverage data come from?
The area coverage data is obtained by a color separation scanner. Recently, however, it has become more common to obtain area coverage data from a plate scanner such as EPS. The surface of the plate is scanned optically and analyzed in both graphic and non-image areas.
The method of directly obtaining data through the CIP3 interface by prepress processing is now more and more widely used.
Eliminate sources of error and avoid false readings
With daily maintenance and calibration, every measurement system can be operated within the most stringent tolerances.
The surface of the printing plate has different structures due to surface treatment and metal processing, which affects the measurement results. Therefore, it is very important to carefully select the plate supplier. At the same time, it is also important to recalibrate the scanner when using a new plate. In this case, make sure there are no handwritten work order numbers or plate color marks in the plate calibration area as this will affect the calibration.