Digital Printing Machine Color Management Example

The amount of ink sucked can be considered from the perspective of the pore size. After the ink is filled in the pores, the hair in the paper will absorb the binder in the ink. If the pores between the fibers of the paper are very small, the capillary action of the fibers will be destroyed and the ink absorption performance will be poor; if the pores between the paper fibers are over Large, strong ink absorption, when the viscosity of the printing ink is low, the capillary not only absorbs the linking material, but also absorbs the pigment, which will cause the ink to penetrate the back of the paper, cause the phenomenon of overprinting, and affect the thickness of the ink layer after drying. The imprinting can not show the proper color saturation on the paper surface, affecting the quality of the printed matter.

Both the permeation stage and the free permeation stage have a great relationship with the absorption properties of the paper, especially the free penetration. Therefore, the stronger the ink absorbency of the paper, the faster the paper absorbs the ink binder and the faster the ink dries. The ink absorption of paper has a lot to do with the quality of prints, and many print failures are caused by the mismatch between the paper's ink absorption and the printing conditions used.

1. Paper absorbs ink too strong

(1) Unbleached and chalky prints In printing, the paper mainly absorbs the binder in the ink. If the paper absorbs the ink too much, the binder is absorbed into the paper layer or coating excessively, resulting in the paper surface. The lack of binder in the ink layer causes the pigment particles to be suspended on the surface of the paper. After the conjunctiva is dried, the imprint of the print is dull or discolored. Even if some imprints are rubbed, the pigment will be exfoliated in a granular form, resulting in chalking. When the powder is severe, during the overprinting process, the ink of the previous color will be peeled off from the surface of the paper after printing.

The solution is as follows

1 Replace the appropriate paper.

2 Use tackifiers to increase the viscosity of the ink, or add a high content of varnish to the ink.

3 Condition the paper.

(2) through the printing

Ink viscosity is small, when the printing pressure is too high, the paper absorbs the ink too strongly, and the binder penetrates the internal pores of the paper, replacing part of the air in the pores of the paper, causing air-fiber, air-filler, and air-paint scattering. The reduction of the interface reduces the light scattering ability of the paper, and the transparency increases, which may lead to the phenomenon of print-through.

The solution is as follows

1 Replace the appropriate paper.

2 Reduce printing pressure.

3 increase ink viscosity.

(3) The density of the ink layer decreases, and the hue changes

When printing on paper with large pores, some of the pigment and binder will penetrate into the paper together (the pores of the paper fibers are larger than the pigment particles). The excessive penetration of the binder will cause the imprints to dry and the tinting strength of the ink to decrease. The saturation of the layer is reduced, so that the color density of the printed matter is significantly reduced. At the same time, a significant reduction in the color density of the printed matter will also change the hue of the printed matter and affect the correct reproduction of the gray balance.

The solution is as follows:

1 Replace the appropriate paper.

2 Perform the gray balance data test again on the paper.

2. The ink absorption of the paper is too weak

The ink absorption of paper is too weak, and the speed of ink absorption is too slow. Although a colorful ink layer can be obtained during the printing process, the penetration and fixation of the ink and the oxidative polymerization are affected, resulting in a lower fixing speed of the ink and the ink is transferred to the paper. After being taken up, it cannot be quickly absorbed by the paper, so that the ink that has not dried will be transferred to the back of the other paper covered above, resulting in stickiness and, in severe cases, blocking.

The solution is as follows:

1 Replace the appropriate paper.

2 Increase printing pressure appropriately.

3 Lower ink viscosity.

4 Reduce printing speed.

Author: Luohong Lian Liu Xin

Reprinted from: Digital Printing