Reason:
1:Plate quality problem ,sensitive film (emulsion film) is too thin or contains impurities, for another recycled aluminum plate
2: plate protector is not enough,Lead to machine stop and scumming ,Content of plate protector in the fountain solution, Increase the amount of the fountain solution (But PrintBar alcohol-free fountain solution R&D when add more quantity then 2% of the fountain solution that will not appear this phenomenon).3.The water corrosion the plate,maybe caused by water quality or added other things that shouldn't have been added
4.From Ink side, Due to the poor water resistance of pigments in ink, Ink formula adjustment is improper, the viscosity reducer and low viscosity inking oil use too much, Ink deployment of too soft too thin and cause paste plate. To solve this problem .one is Choose a good water resistance ink .two is Adjust the dosage of various printing auxiliaries. To ensure the ink water resistance, ink-water balance.
5.From printing fountain solution side, The fountain solution PH value is low and heavily acidic, ink scumming, That means it's etched print image. Ink drying time is long,You need alkalinity to increase the PH. The reason is it's too acidic, Because our fountain solution is acidic, So appropriate to reduce the amount of fountain solution added.