Patent ID: 7494199

Claim:
A head control device that applies a driving signal to an electromechanical transducing element to change a shape of the electromechanical transducing element to change a volume of a liquid droplet ejection chamber filled with a liquid for ejecting a liquid droplet through a nozzle in communication with the liquid droplet ejection chamber, the head control device comprising: a head driving unit that generates the driving signal including a plurality of cycles of a plurality of driving pulses, and selects and applies at least a portion of one of the driving pulses to the electromechanical transducing element, each of the driving pulses having a contracting portion changing from a first level to a second level for discharging the electromechanical transducing element from a first potential corresponding to the first level to a second potential corresponding to the second level to contract the electromechanical transducing element from a first shape to a second shape, and an expanding portion changing from the second level to a third level to charge the electromechanical transducing element to a third potential corresponding to the third level to expand the shape of the electromechanical transducing element to eject the liquid droplet; and a re-charging portion, in at least one driving pulse in each cycle and subsequent to the expanding portion, changing from the third level to the first level to recharge the electromechanical transducing element to the first potential, without affecting ejection of ink droplets in the expanding portion, wherein the electromechanical transducing element to be recharged by application of the re-charging portion corresponds to a nozzle not ejecting a liquid droplet in the cycle, and wherein the recharging portion is a first instance of a change from the third level to the first level of the driving signal applied to the electromechanical transducing element in the cycle, and wherein each of the driving pulses is a corresponding portion of the driving signal which starts at the first level, then varies from the first level, and then ends at a first instance of return of the driving signal to the first level.