Liquid ejection head and liquid ejection apparatus

A liquid ejection apparatus comprising:

• a plurality of rollers for conveying a print medium;
• and
• a liquid ejection head configured to eject liquid onto the conveyed medium and including:
• a nozzle,
• a pressure chamber that is capable of storing the liquid and communicates with the nozzle, a volume of the pressure chamber being varied to eject the liquid from the nozzle,
• an actuator configured to vary the volume of the pressure chamber in response to a drive signal, and
• a drive circuit configured to generate the drive signal, wherein
• the pressure chamber has one of states including:
• a steady state in which the volume is unchanged,
• an expanded state in which the volume is expanded, and
• a contracted state in which the volume is contracted,
• the drive signal includes:
• a first waveform that causes the pressure chamber to transition from the steady state to the contracted state, and then transition from the contracted state to either the steady state or the expanded state,
• a second waveform for causing the liquid to be ejected from the nozzle, wherein the second waveform is subsequent to the first waveform and causes the pressure chamber to transition either from the steady state to the expanded state, and then transition from the expanded state to the steady state, or directly transition from the expanded state to the steady state,
• a third waveform that is subsequent to the second waveform and causes the pressure chamber to transition from the steady state to the contracted state, and then transition from the contracted state to the steady state, and
• a fourth waveform that is subsequent to the third waveform and causes the pressure chamber to transition from the steady state to the expanded state, and then transition from the expanded state to the steady state, and
• a duration of the fourth waveform is shorter than a duration of the third waveform, and is at least 1 μs or 0.5 times a half cycle of a main acoustic resonance frequency of the liquid in the pressure chamber so that the fourth waveform does not cause the liquid to be ejected from the nozzle.