Image forming method, image forming apparatus and inkjet head

An image forming apparatus, comprising:

• an inkjet head including a pressure chamber filled with ink, a nozzle which communicates with the pressure chamber and in which a meniscus of the ink is formed, a piezoelectric element which pressurizes the pressure chamber, and a drive circuit which performs an operation of ejecting the ink in a printing state and generates a basic pulse for vibrating the meniscus in a non-printing state, the basic pulse being generated by turning off a voltage applied to the piezoelectric element for substantially the same period as a natural vibration period of the ink;
• a recording-medium storage unit configured to store a recording medium;
• a recording-medium conveying unit configured to convey the recording medium;
• and
• a recording-medium output unit configured to store the recording medium after an image is formed on the recording medium,
• wherein an additional pulse is generated at least once before or after the basic pulse when the basic pulse is generated by the drive circuit in the non-printing state, the additional pulse being generated by turning off the voltage applied to the piezoelectric element.

An inkjet head, comprising:

• a pressure chamber filled with ink;
• a nozzle which communicates with the pressure chamber and in which a meniscus of the ink is formed;
• a piezoelectric element which pressurizes the pressure chamber;
• and
• a drive circuit configured to generate a basic pulse for vibrating the meniscus in a non-printing state, the basic pulse being generated by turning off a voltage applied to the piezoelectric element for substantially the same period as a natural vibration period of the ink;
• wherein the drive circuit is further configured to generate an additional pulse at least once before or after the basic pulse in the non-printing state, the additional pulse being generated by turning off the voltage applied to the piezoelectric element.