HP Designjet 2500.3500cp Printer series - Manual (Page 101)

Working with Ink Systems
About the Ink System
4-5
When Does the Ink System Refill the Printheads?
Normally the printheads are refilled when a print has been finished. If you are
printing an image with a high ink density which is larger than E/A0, the printer may
stop during the print to refill. The printer contains algorithms to find the best place
in a print to stop for a refill. If you are using UV pigmented ink, you may not be
able to print a large image without the printer stopping to refill the printheads.