Abstract: The present disclosure is drawn to an ink supply tank for a printer. The ink supply tank includes a main chamber to supply a printer with ink. The main chamber includes a fill port to receive ink during filling and an exchange port to release the ink. A chamber separator device is configured with a fill surface and a vent port. An overflow chamber can be configured with a vent to pass air into the overflow chamber, a first portion of air in the overflow chamber passes through the vent port of the chamber separator device to a feeder chamber to replace a second portion of ink leaving the ink supply tank to feed a print head and the vent port of the chamber separator device to pass a third portion of ink and a second portion of air from the feeder chamber to the overflow chamber.