FEATHERING


Irregular edges around a print, often undesirable marks made on the image's trailing edges, generally caused by an excessive build-up of ink.

 

Causes:

- Incorrect pressure set up in printing unit;

- Ink drying on plate;

- Improper setting of metering system;

- Uncontrolled ink viscosity;

- Incorrect solvent balance;

- Debris and dust being picked up from the substrate;

- Out of true plate cylinder;

- Static electricity.

 

Solutions:

- Reset pressure between all rollers;

- Clean plates thoroughly. Speed up press. Slow down drying by adding slower solvents. Ensure ink unit tray covers are in place;

- Reset pressure settings between fountain roll nip and doctor blade assembly;

- Maintain correct viscosity, do not allow to drift too high. Use ink tray covers to improve ink solubility;

- Modify solvent balance;

- Clean off when necessary, lower ink viscosity to lower its tack. Use web cleaning devices when required. Tacky polymers not cured properly during manufacture;

- Check roller is true;

- Use static eliminators. Reduce tack of the ink and clean plate.