The presence of a faint image of a design in areas, which are not intended to receive that portion of the image. Usually a repeat pattern in the press machine direction.
Causes:
– Ink starvation caused by large images being inked from the same area of the anilox before fresh ink can be applied;
– Anilox and/or fountain rolls not properly cleaned;
– Premature drying of ink on anilox roll;
– Ink solubility.
Solutions:
– Change diameter of plate cylinder or change speed ratio between the fountain roll to the anilox roll. Change anilox roll to a higher specification. Increase ink flow in a chambered system;
– Thoroughly clean fountain roll and/or anilox roll;
– Change anilox to one with the same volume but with a coarser screen. Cover anilox from ambient air or blown air from dryers. Increase the dwell time in chambered systems with greater openings assisting in rewetting of rolls. With solvent inks (and sometimes water) the viscosity may be too low. A higher viscosity should slow the drying on the anilox rolls. Reduce blade pressure alleviating friction and heat at the sheer point of the ink;
– Balance solvents;
