WATER - BASED INK HOW TO CONTROL THE DRYING TIME

Water-based ink can be mixed with water before drying, once the ink is dry, it is no longer soluble in water and ink. So before the use of water-based ink must be fully stirred to keep the ink composition uniform. Add ink, ink tank in the remaining ink such as impurities should be filtered out first, and then with new ink use.

Do not let the ink dry fixed on the anilox roller, so as not to block the ink hole. Obstruct the quantitative transfer of ink resulting in printing instability. In the printing process, the flexo should always be wet with ink to avoid blocking the text pattern on the printing plate after drying the ink. In addition, it is found that water-based ink viscosity is slightly larger, it is not suitable to add water casually, so as not to affect the stability of the ink, and the right amount of stabilizer can be added to adjust.

In order to obtain a reasonable flexographic water-based ink drying rate, there are several suggestions in the process of use.

1, appropriately improve the pH value of water-based ink to reduce the drying speed of the printing process, and does not affect the drying speed. The pH value is generally controlled in 8.5~9.5. Dry too fast, by adding stabilizer to control the pH value in more than 9, but can not exceed 9.5, otherwise the nature of the ink will change.

2. Under the condition of not affecting the printing speed, try to make the water-based ink dry a little slower, which can be adjusted by adding slow-drying agent. Different ink to add the amount of slow drying agent is different, generally not more than 5%. Add slow drying agent after the ink thickens, pH value will be reduced.

Therefore, in addition to the slow drying agent at the same time to add water and stabilizer to control ink viscosity and pH.

3. When printing thin paper products, reducing the drying speed of water-based ink can reduce the degree of paper warping. This is usually regulated by the addition of slow drying agents or blockers. This is due to the water-based ink in the printing ink, the water and alcohol volatilization, so that the paper in the middle of the tight on both sides of the loose and warping. The role of the slow drying agent is to let the ink can not immediately dry, reduce warpage.

4. Enhance the convection speed of the air in the oven, which can obviously accelerate the drying speed of printed matter. Because water-based ink contains a lot of water and alcohols, enhance convection can reduce the relative humidity in the oven, accelerate the solvent volatilization.

5, adding slow drying agent can solve the problem of printing abrasions and varnish plate surface sticky. Ink drying too fast will cause ink does not enter the penetration stage on the surface of the substrate material, resulting in insufficient adhesion, ink layer is easy to fall off, in overprinting or polishing, after the color plate will be the first color of the ink stick off, this can also be adjusted to change the color sequence or reduce the ink viscosity.

6, add slow drying agent and speed, can reduce the blocking phenomenon. Printing speed is too slow to make the ink spread on the plate, resulting in dot adhesion, but the ink drying too fast will make the ink can not be fully transferred, resulting in the dot around the ink, causing the phenomenon of blocking the plate.

7, guide paper heating, can also accelerate the printing drying speed. When the printing ink is large, if the drying capacity of the printing press is limited, each time the speed is not fast when the machine is just started, after a period of time, the speed has a certain space to improve, this is the edge of the paper guide roller heating. Guide roller heating ink is not easy to stick to its surface, before starting, independent drying device opened in advance, just opened the equipment can be turned off the suction device, so that the equipment can accumulate the maximum heat in the shortest time, the speed can be rapidly improved.

8, when printing ink is large, try to choose high color concentration of ink, high line number of roller, which is conducive to printing dry, can also reduce the phenomenon of water grain.

9, the higher printing speed required by the ink viscosity is lower, is conducive to the transfer of ink.