What should you pay attention to when using water-based ink during gravure printing?
1. The printing plate uses an electroengraving plate or a laser plate, and the plate depth is between 15μ and 20μ. This is because the ink is produced using tap water, which has a higher boiling point than the solvent. A shallow plate can increase the printing speed and avoid water ripples. If you use solvent ink to print on a printing plate with a depth of 35μ~40μ or above, water ripples will occur, while using ink printing on a printing plate with a depth of 25μ or above will also cause water ripples. Therefore, Using good printing plates is crucial.
2. Good drying equipment. The drying temperature should be determined according to the substrate and the size of the printing area. For example, for wine label printing on metal aluminum foil, the drying temperature should be above 100°C, while for plastic The printing and drying temperature of the film is preferably 60℃-80℃, and the wind force should be stronger than when printing with solvent ink. In addition to the temperature, there should also be strong wind, so that the ink can be applied to the substrate during installation. Can dry quickly.
3. Except for metal aluminum foil, vacuum aluminum-plated film, and paper, all plastic films need to be EDM treated before using ink printing. The dyne on the plastic surface is above 40 to 42, and water is used as the main solvent. The surface tension of the produced ink is around 72 dynes, so a large gap between the tension of the ink and the tension of the film affects the adhesion, thereby increasing the surface tension of the plastic film and enabling good adhesion of the printed pattern.
4. Before printing, after the ink is poured into the ink tank, the printing plate is idle for 2-3 minutes to moisten the printing plate and stir; during the printing process, in order to observe the printed product When printing needs to be stopped, the printing plate must not stop rotating to avoid plate jam caused by dry strands of the printing plate.
5. After adjusting the printing viscosity according to the depth of the plate before printing, try not to add tap water during the printing process. Just add new ink with the same viscosity. The reason is that during the printing process, the ink is 32 For 1 hour at ℃ temperature, the volatilization is only 1.2, and the viscosity change is small, so the ink can keep the color of the printed matter consistent and improve the pass rate of the printed matter.
6. After printing, clean the printing plate immediately, pour ink into the bucket and cover it, put clean water into the ink tank, rotate the printing plate for cleaning or mix 3 washing powder solution for cleaning.