In some small and medium-sized packaging printing enterprises using single and two-color offset presses, the overprint deviation of four-color color printing is often a headache for workers. The front two-color overprint is generally no problem, but the overprint accuracy of the back two-color is more difficult to control.Offset overprint deviation control method.
Generally, measures such as reducing mechanical speed, reducing ink volume, adjusting ink fluidity and powder spraying can only be taken, but the effect is also great. The above measures affect work efficiency and product quality. At the same time, the operation is complex and greatly improve labor intensity.Offset overprint deviation control method.
In fact, overprint technology can be divided into dry overprint and wet overprint. The so-called wet printing refers to that both inks during printing are wet ink, that is, the previous color has just been printed, then printed, and then printed.Offset overprint deviation control method.
However, dry printing is the color printed after the ink is dried.Offset overprint deviation control method.
1 dry overprint.
The advantages of this printing method are that in the subsequent printing, the paper positioning is stable, the printing position is basically fixed, and the printing overlap of dry ink can obtain rich, bright and correct colors. However, due to the need to stop for a certain time, the expansion and deformation of the paper is easy to occur, which is not allowed by the jacket, and the work efficiency is not high. In order to make jacket printing more correct, it can only be solved by controlling layout moisture, reducing printing pressure and lining thickness.Offset overprint deviation control method.Offset overprint deviation control method
2. Wet overprint.
This printing method has high efficiency, and the paper is printed correctly due to small deformation. However, if the ink volume is large or the printing area is large, the back is easy to get dirty, the color of the printed matter becomes dark, and the paper positioning in subsequent printing becomes difficult, which is easy to affect the correctness of printing. Offset overprint deviation control method
Of course, having an advanced four-color offset press can solve the problem, but usually only large enterprises have such conditions. Ordinary monochrome and two-color machines can only be solved through the increase of experience and labor.Offset overprint deviation control method