Solutions for Electrostatic Faults in Flexographic Printing

Static electricity refers to static electricity generated during high-speed start-up. Once static electricity is generated in thin paper products, it is very troublesome for the next process cutting. After the paper is die-cut, the finished product tends to slide down against the bottom roller, sometimes falling, sometimes just between the bottom roller and the front end of the delivery table. When it falls, it will cause a small amount of waste products. If the paper is stuck, it will be shut down and it will cause waste. The main reason for the above problems is that the thin paper itself has poor stiffness and is prone to static electricity. The solution is to install an effective static removal device in front of the die-cutting unit; add a thin steel sheet fixed at the front of the delivery table and resting on the surface of the paper roll to ensure tight seams. Sometimes thin paper products fly up along with the die cutting roll on the delivery table. The main reason is that the coating oil is not completely cured and is a little sticky. At this time, only the curing properties of the coating oil need to be improved, and the die cutting can be changed frequently. The sponge lining or add a small amount of talcum powder, to add less ground, the most fundamental is to ensure that the varnish is not completely cured sticky.

Die-cutting and take-up issues are registration issues. It should be said that the tension control of a unit type flexographic press when printing thin paper is much easier than that of printing a paper jam. Based on years of experience, if the front overprint is better and the die cut deviation is larger, it is mostly because the back tension is too large or inappropriate and overprinting is not allowed. So most of the flexographic presses nowadays are equipped with computerized automatic systems. It should be emphasized that different roll design inputs are also different, and there is a habit of recording data.