Nine steps to solve the ink problem in Chocolate Paper Boxes printing

Nine steps to solve the ink problem in Chocolate Paper Boxes printing

1. Judge the scraper adaptability and transferability of the ink.

The ink on the gravure printing plate cylinder is not clean, and the ink in the printing ink tray is thickened, and the printed matter will not be colored, hang dirty, run off ink, knife wire, knife line and so on. Staining and ink running of the printed matter are related to the adjustment of the ink viscosity. The short-term layering phenomenon of the ink can cause the smearing. If the ink viscosity is high, the ink running phenomenon will occur, but it is closely related to whether the angle and pressure of the scraper device are correct or not. . It is only when the ink on the full printing plate cylinder cannot be wiped clean, and the place cannot be wiped clean by pressing it with a finger or changing the new ink, it may be a problem with the ink. If it can be wiped clean after replacing the new ink, there is a problem with the thinner added in the ink.

The solution is: replace the ink or thinner, and readjust the scraper.

2. Inspection of printing substrate (plastic film).

If the ink has phenomena such as missing printing, white spots, orange peel, and poor adhesion, it is first necessary to detect the surface tension and static electricity of the printing substrate. If the surface tension of the printing substrate is lower than 35dyn, the adhesion of the ink will be poor, and orange peel, ink spots and ink whiskers will appear in the static electricity assembly.

The solution is to perform surface treatment on the printing substrate, install static elimination equipment on the relevant parts of the printing machine, increase the humidity in the workplace, and adjust the drying speed of the ink with a slow-drying solvent. If the printing ink is thinned, the effect of increasing the printing speed will be better.

3. Inspection of the purity and smell of the diluent.

If the purity of the diluent from the original ink to the diluted ink is poor, the solvent residue of the printed matter will increase, and there may also be residual odor on the printed matter.

Check the purity of the solvent first. The simple test method is: pull a white paper strip 8cm wide and put it in the solvent to wet it, then take it out and wave it with a little force to observe the drying speed of the solvent on the white paper strip or whether it changes color, and then Smell the white strip for any residual odor. Waving the white paper strip for 8 to 15 times, it is normal for the solvent to volatilize and dry. If it is not dried, the solvent volatilization speed is slow, otherwise, the volatilization speed is fast. The white strips of paper are discolored, except for rust in the solvent barrel, indicating a problem with the solvent. If there is a residual odor after the solvent evaporates, the purity of the solvent is not enough. The original ink and the diluted ink were scraped on the film and tested after drying. The scraping residue of the original ink is large, and the scraping residue of the diluted ink is small, which means it is normal. On the contrary, there is a problem with the diluted solvent. If the scraping sample of the original ink has residual odor, there is a problem with the ink. If you smell a peculiar smell on the scraped sample of the diluted ink, the solvent used in the thinner is not pure.

The solution is to replace the ink or adjust the solvent of the thinner.

4. Correct use of slow drying agent.

The slow-drying agent in the ink, or the slow-drying diluent used in the printing ink is incorrect, which will cause the phenomenon of biting (eating or dissolving) color in the printing, and the phenomenon of false drying or anti-sticking of the printed matter.

The solution is to change the diluent formula of the printing ink, adjust the drying performance of the printing ink, and improve the printing speed.

5. The application of diluents with different ratios.

Different ratios of ink diluents in printing can adjust the drying performance of the ink, the color concentration of the ink, and the viscosity of the ink. Adjusting the dryness of the ink is beneficial to increase the printing speed and improve the clarity of the printed matter. Adjusting the color density of the ink can reduce the pressure of the embossing rubber roller or the workload of the ink scraper, which is beneficial to the improvement of the printing speed. Adjusting the viscosity of the printing ink is the key to controlling the amount of ink applied or adapting to the printing speed and room temperature of the printing place.

The solution is: according to the printing speed, the depth or the number of lines produced on the printing plate roller (roller) drum, and the room temperature of the printing place, prepare a quick-drying, medium-drying, slow-drying or extra-slow-drying thinner.

6. How to use from high viscosity to low viscosity.

The printing speed is slow, and the printing plate graphics and texts are relatively deep. It is necessary to use high-viscosity printing ink, otherwise the pattern on the printed matter will form water ripples due to the low viscosity of the ink. The printing speed is fast, and the printing plate graphics and texts are relatively shallow. It should be printed with low-viscosity ink. Otherwise, the printing pattern will be insufficient or missed due to the high viscosity of the ink. The printing machine is also due to the high ink viscosity. Large, resulting in the printing speed can not open up.

The solution is to apply diluents and diluents to adjust the viscosity of the printing ink.

7. In the use of spot color ink and metal ink, the use of ink distribution roller.

Spot color ink printing requires consistent and uniform ink color, and copper and gold powder in metal ink is easy to precipitate, so it is very necessary to use an ink distribution roller in printing, and an ink stirring rod should be placed in the printing ink tray. In addition, in the use of spot color ink, the diluent should be used together with the diluent, and it is not suitable to use the solvent alone to dilute. Metal ink should not be diluted with solvent. The correct method is to add diluent to adjust.

8. The use and mixed use of non-true solvents.

Although the non-true solvent solvent cannot dissolve the connecting resin in the ink, it can reduce the viscosity of the printing ink and reduce the phenomenon of biting (eating or dissolving) color during printing.

9. Adhesion test of Chocolate Paper Boxes.

Tape onto the print, flatten it with your fingers, and make it tightly bonded to the print, then slowly lift it halfway up its full length, then quickly lift the other half. The less the ink sticks from the printed matter, the stronger the adhesion of the ink on the printed matter is, otherwise the adhesion is poor. If the ink on the printed matter is glued down by more than 40%, it means that the printing ink on the printed matter has unqualified adhesion.

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