Fluid ejection device, driving method of fluid ejection device, and operating instrument

A driving method of a fluid ejection device comprising:

• the fluid ejection device including:
• a fluid chamber whose capacity is variable,
• an inlet flow path and an outlet flow path communicating with the fluid chamber,
• a capacity changing unit which changes the capacity of the fluid chamber, the capacity changing unit including a piezoelectric element,
• a fluid supplying unit which supplies fluid to the inlet flow path,
• a nozzle including a fluid ejection opening disposed at an end of the outlet flow path opposite to an end communicating with the fluid chamber,
• a vibrating unit,
• a vibration detecting unit including a sensor, and
• an operation control unit;
• the method comprising:
• vibrating a component in the vicinity of the fluid ejection opening by the vibrating unit;
• detecting the level of vibration of the nozzle in the vicinity of the fluid ejection opening by the vibration detecting unit;
• and
• supplying drive signals that control operation of the capacity changing unit based on the level of the vibration detected in the vibration detecting step by the operation control unit, the drive signals causing the piezoelectric element to expand or contract to change the capacity of the fluid chamber.