Inkjet recording device and inkjet recording method

An inkjet recording device of a continuous ejection type charge control type, comprising:

• an excitation voltage circuit which applies an excitation voltage to a piezoelectric element provided in an ink nozzle that ejects ink droplets;
• a charging electrode which charges the ejected ink droplets;
• a deflection electrode that deflects a flying direction of the ink droplets charged by the charging electrode;
• a charge amount sensor that measures a charge amount of the ink droplets charged by the charging electrode;
• and a control section which controls the excitation voltage circuit, the charging electrode, the deflection electrode, and the charge amount sensor,
• wherein the control section includes:
• an excitation voltage sweep setting unit that applies an excitation voltage value to the piezoelectric element over a plurality of sweeping events so as to sweep from a high voltage side to a low voltage side in a predetermined voltage range in a state in which the deflection electrode is de-energized;
• a printing phase measuring unit that applies a charge voltage to the ink droplets generated by the applied excitation voltage value at a plurality of arbitrary printing phases to give an electric charge to the ink droplets, and detects the amount of the electric charge given to the ink droplets by the charge amount sensor to obtain an appropriate printing phase;
• and
• an excitation voltage determining unit that, when the relationship of the current printing phase to the previous printing phase detected for each sweeping event is reversed from an increasing side to a decreasing side and two decrease determinations of the printing phase are established in succession, sets an excitation voltage value corresponding to a printing phase of a sweeping event between two sweeping events before the first decrease determination and two sweeping events after the first decrease determination as a final excitation voltage value.