Abstract: A sub-tank is pressurized by a pump, with head valves closed. Then, one of the head valves is opened to perform a first purge on a first head. After the one head valve is closed, a different one of the head valves is opened to perform a second purge on a second head different from the first head. After these purges, an open-to-atmosphere valve is opened, with the head valves closed, to decrease the pressures inside the heads which are increased by the purges. This allows a selective purge on only a head which requires a purge. As a result, the amount of ink forced out is suppressed during the pressurized purges. After the sub-tank is made open to the atmosphere, a depressurizing pump depressurizes the sub-tank to form ink menisci in the heads. This prevents air bubbles from being drawn into nozzles during the formation of the ink menisci in the nozzles after the purges.

Abstract: A sub-tank is pressurized by a pump, with head valves closed. Then, one of the head valves is opened to perform a first purge on a first head. After the one head valve is closed, a different one of the head valves is opened to perform a second purge on a second head different from the first head. After these purges, an open-to-atmosphere valve is opened, with the head valves closed, to decrease the pressures inside the heads which are increased by the purges. This allows a selective purge on only a head which requires a purge. As a result, the amount of ink forced out is suppressed during the pressurized purges. After the sub-tank is made open to the atmosphere, a depressurizing pump depressurizes the sub-tank to form ink menisci in the heads. This prevents air bubbles from being drawn into nozzles during the formation of the ink menisci in the nozzles after the purges.