Abstract: A system for delivering ink to a printhead is for use with an ink reservoir. The ink delivery system includes an ink delivery device, a vacuum pump, a bladder, a sensor, a separator and a controller. The ink delivery device is connectable to and in fluid communication with the ink reservoir. The vacuum pump is operably connected to and in fluid communication with the ink reservoir. The bladder defines a volume. The sensor is operably connected to the bladder and the sensor generates a signal responsive to volume of ink in the bladder. The separator is operably connected to and in fluid communication with the ink delivery device, the vacuum pump and the bladder. The controller is operably connected to the sensor for determining the change in the size of the bladder and thereby determining ink usage and the controller being operably connected to the ink delivery device.