Overprintability in multi color prints
Ink
Problem
1. Too thick.
2. Too slow.
Solution
1. Use new ink.
2. Use faster thinner.
Cliche
Problem
1. Too deep.
2. Wrong screen ruling.
Solution
1. Produce new cliche with shallower etching depth.
2. Test new cliche with different fineness of halftone screen.
Pad
Problem
1. Rough surface.
Solution
1. Replace pad.
Substrate
Problem
1. Very slick, dense material structure.
Solution
1. Substrates where surfaces cannot be dissolved by thinner are esp. problematic (e.g., glass).
Other
Problem
1. Insufficient pretreatment or subsequent treatment.
Solution
1. Heat objects before printing, or ventilate them for thinner to evaporate faster.
During high speed printing operations, the last ink printed may be removed by next pad. This occurs particularly
on larger surfaces, where material cannot be dissolved by thinner, or with slower inks in connection with
carree or rotary indexing tables and linear belts. The Problem
hardly ever arises when adjustable tables areused. The best Solution
is to pre-heat objects or dry them with cold or hot air at intervals during the printing run.
