How to control "water-ink balance"

How to master the "ink-ink balance" is a difficult point in the offset printing process.

If the moisture is too small, the blank part will be dirty, and the amount of water is too large, it will affect the printing quality.

Water hazards include the following:

(1) Obstructing the normal transmission of ink and forming false imprints;

(2) The ink color is uneven, especially before and after printing interruption;

(3) increase the deformation of the paper caused by overprinting is not allowed;

(4) The amount of water absorbed by the paper is too much to produce curls and the paper is not delivered together;

(5) Wet the cylinder pad or make the drum shell rusty;

(6) Due to the ink dimming, the picture is dry, the outline is unclear, and the color is old;

(7) The coloring power of the ink is reduced, sometimes the ink volume has to be increased, so that the outlets become pasty, the level is unclear, and the water and ink are large;

(8) The color of the print changes greatly, causing color error compared with the sample;

(9) The gloss of the imprint decreases, and the drying speed becomes slower;

(10) Accelerate the deinking of the ink roller, and the ink will become large, which will cause the printing surface to be dirty and will make the back of the printed sheet sticky.

Therefore, under normal circumstances, the ink-water balance should maintain the minimum amount of water, but it cannot be mechanically specified. The amount of water used depends on the speed of the machine, the area of ​​the layout, the nature of the paper, and the thickness of the ink layer.

The water consumption of the control layout should be based on the premise that the layout can not afford to be dirty. Whether the amount of water in the layout can be correctly identified is a necessary condition for the control of water consumption. Now, the identification of the amount of water is usually estimated by experience, and it needs to be repeatedly explored.

Here are some signs of excess water:

(1) Water droplets accumulate at the rolling "points" of the lower ink roller and the water transfer roller;

(2) Imprinted ink is light, it is not easy to deepen the ink color after adding ink;

(3) The ink roller surface has a lot of ink, but the ink color is not deep;

(4) Before and after the interruption of printing, there is a large gap in ink;

(5) Compared with the original paper, the printed sheet is weak;

(6) The edge of the paper is curled downward and the paper is not evenly distributed;

(7) Occurrence of vacant emptiness on the edge of the stamp and the large area of ​​blank space;

(8) The blanket cylinder and plate cylinder liner are wetted with moisture;

(9) Various other phenomena of "great water, ink, and big".

Through daily observation and analysis, various phenomena of excessive water consumption can be detected in a timely manner and controlled to ensure the quality of printed products.

Source: Bison