Patent ID: 7934790

Claim:
A method of maintaining an inkjet head which comprises a nozzle plate including a nozzle which ejects ink, the method comprising: performing a purging process comprising pressurizing an interior of an ink passage which communicates with the inkjet head, and applying to the inkjet head a first positive pressure at which the ink drops from the nozzle plate; and performing a pressure reduction process comprising, after performing the purging process, reducing the pressure applied to the inkjet head from the first positive pressure to a second positive pressure, while maintaining the pressure applied to the inkjet head in a positive pressure state; wherein the pressure reduction process comprises intermittently releasing air from the ink passage which communicates with the inkjet head a plurality of times so as to reduce the pressure applied to the inkjet head from the first positive pressure to the second positive pressure; and wherein when the air is released intermittently a plurality of times, an amount of air released from the ink passage during a first air release of the plurality of times is larger than an amount of air released from the ink passage during a final air release of the plurality of times.