A print defect where an unwanted image appears, often as a dark line in a light or solid print area. Tracking occurs when two print stations, which are often next to each other, interact.
Causes:
– Excessive ink application;
– Dirty printing plates;
– Ink viscosity too high;
– Ink drying too slowly;
– Die cutting or folding operations:
- Worn or rough anvil blankets;
- Excessive cutting die pressure;
- Worn or slipping folding belts;
- Guides, rails or bars hitting print;
- Stacker belts hitting print.
Solutions:
– Clean and replace doctor blade;
– Clean plates;
– Reduce viscosity;
– Increase drying speed of ink by reducing viscosity, reducing ink film thickness with better metering. Decrease machine speed and increase dryer temperature;
– Optimise converting operations: Replace or trim/grind anvil blankets;
– Remove die rubber, replace knives, reduce die pressure, replace anvil blankets;
– Replace or adjust folding belts;
– Adjust or remove to minimise impact;
– Move or lift belts from print areas.
