To suppress shift of impact timing changed by the number of liquid droplets continuously delivered within a predetermined driving period.
When small droplets are delivered, after 20 [μs] from starting the predetermined driving period, a driving waveform with a voltage with an amplitude A is applied on a driving element. When middle droplets are delivered, a driving waveform with a voltage with an amplitude B (A>B) after 10 [μs] from starting the driving period and the driving waveform with the voltage with the amplitude A after 20 [μs] from starting the driving period, are continuously applied on the driving element. When large droplets are delivered, a driving waveform with a voltage with an amplitude C (B>C) when starting the driving period, the driving waveform with the voltage with the amplitude B (A>B) after 10 [μs] from starting the driving period, and the driving waveform with the voltage with the amplitude A after 20 [μs] from starting the driving period, are continuously applied on the driving element.
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda