This Canon PFI-8120 is designed for large volume printing and employs a tubing system that allows ink to be supplied continuously from the ink tank to the print head. Canon's unique sub-ink tank system allows for users to use all of the PFI-8120 ink that's available in a tank before having to replace it, helping eliminate any wasted ink. The empty PFI-8120 tanks can also be replaced on-the-fly without stopping the printer. This is extremely useful during long print jobs.