1. Too slow to dry
If the drying speed is too slow, it will cause precipitation, contaminating and sticking the guide roller. When the drying speed of the diluent solvent is too slow, and the special solvent cannot fully meet the requirements, the quick-drying solvent should be used. If the plate depth is too deep, if you have to use a deeper plate depth, you should use a quick-drying solvent and slow down the printing speed.
2. Anti-sticking
A phenomenon in which the ink printed on the previous plate is transferred to the surface of the next plate. The adhesion of the ink is insufficient. The ink film printed on the previous plate is dissolved on the next plate. In addition, the printing speed is too slow is also a reason, so it is necessary to increase the speed.
3. Arc crater
When the printing surface is dried by intense heat, the drying of the surface layer progresses rapidly, and the solvent sealed inside suddenly boils and sprays onto the surface. The hot-air drying of rapid gathering can only promote the drying of the surface, so the dryer is best to use low temperature-high temperature-low temperature or arch temperature curve type. In addition, it is better to use slow-drying solvents in ink cleaning to slow down the drying speed.
4. Gelation
The ink loses its fluidity and solidifies into a gel-like phenomenon. Gelation due to low temperature, the temperature should be kept higher than the gelation point and the ink should be stirred.
5. Ghosting
Shadow ink marks are also transferred to the unetched parts of the plate. Rub the ink on the chrome surface with paper, or try re-chrome plating when it is serious. Sometimes it can be solved by replacing the ink with a new one. The ink printed on the previous page is re-dissolved on the white empty surface of the next page, and a light-colored image appears outside the image range of the next page. Be careful when running at low speeds.
6. Poor adhesion
The ink thickness is not reached, and there is no adhesion. Usually, a simple test (celluloid tape) is used to detect whether there are any abnormalities in printing.
7. Insufficient drying
The heater of the dryer can be used to heat within the allowable range.
8. Deterioration
The ink loses its fluidity, the viscosity rises abnormally, and the gloss decreases, resulting in poor adhesion, and the remaining ink can no longer be used. Therefore, in the event of an abnormality, new ink should be added or all replaced.