Watermark processing method of screen printing
The so-called "watermark" in the production process of screen printing is the trace caused by the impurities of some sensitizer and developer remaining on the screen surface after the sensitizer is baked. Because the traces are not obvious, they can only be observed by naked eyes at a certain angle, which generally show screen printing faults such as "no ink leakage" or "bad ink leakage".
We usually wash the printing plate with tap water in the process of making screen plates. However, when the screen printing time is too long or the water flow is too fast, it is easy to cause the printing effect of the screen pattern to be unsatisfactory, and the printing resistance rate is relatively low, and the screen printing fault such as large-scale ink leakage or ink failure occurs during screen printing; However, if the flushing time is too short or the water flow is too slow, it is easy to cause the so-called "watermark". The following will explain the watermark processing method of screen printing for you:
After the screen exposure is completed, quickly wet both sides of the printing plate with tap water. The water flow speed should not be too fast or too slow. The control of the water flow speed should be based on not washing away the photosensitive agent on the screen surface. After fully wetting the layout, slightly increase the water flow speed, and only flush the non-printing side of the screen, that is, all the unexposed sensitizer (non-printing pattern part) flows down. Put the screen vertically for a while (about 3 ~ 5 minutes), put the screen into the oven after completion, and when the screen is completely dried, you will find that the "watermark" on the screen disappears.