An inkjet recording device automatically determines an excitation voltage of a piezoelectric element for formation of ink droplets. An excitation voltage value is applied to the piezoelectric element of a nozzle over a plurality of sweeping events. A charge voltage is applied to ink droplets generated by the applied excitation voltage value in a plurality of arbitrary printing phases to give an electric charge thereto. A charge amount given to the ink droplets is detected by a sensor to obtain a printing phase. When the relationship of a current printing phase to a 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, an excitation voltage value corresponding to the printing phase of the sweeping event immediately before the first decrease determination is set as a final excitation voltage value.

An inkjet recording device automatically determines an excitation voltage of a piezoelectric element for formation of ink droplets. An excitation voltage value is applied to the piezoelectric element of a nozzle over a plurality of sweeping events. A charge voltage is applied to ink droplets generated by the applied excitation voltage value in a plurality of arbitrary printing phases to give an electric charge thereto. A charge amount given to the ink droplets is detected by a sensor to obtain a printing phase. When the relationship of a current printing phase to a 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, an excitation voltage value corresponding to the printing phase of the sweeping event immediately before the first decrease determination is set as a final excitation voltage value.

A print head equipped with a contamination detection device detects ink contamination of a print head of a continuous-type inkjet printer and includes a print head that includes a nozzle that ejects ink droplets, charging electrodes that charge the ink droplets, deflection electrodes that deflect the charged ink droplets with an electric field, and a gutter that collects the ink droplets that are not used for printing, and a contamination detection device that includes a camera that images at least a part of a flight region where the ink droplets ejected from the nozzle fly from a side in a direction in which the ink droplets are ejected from the nozzle or in a direction in which the deflection electrodes face each other, and an information processing unit that performs processing of image data captured by the camera.

A print head equipped with a contamination detection device detects ink contamination of a print head of a continuous-type inkjet printer and includes a print head that includes a nozzle that ejects ink droplets, charging electrodes that charge the ink droplets, deflection electrodes that deflect the charged ink droplets with an electric field, and a gutter that collects the ink droplets that are not used for printing, and a contamination detection device that includes a camera that images at least a part of a flight region where the ink droplets ejected from the nozzle fly from a side in a direction in which the ink droplets are ejected from the nozzle or in a direction in which the deflection electrodes face each other, and an information processing unit that performs processing of image data captured by the camera.

An electrohydrodynamic printer has a fluidic extractor. A stream of liquid or carrier fluid at a different electrical potential than the printing fluid passes by an extraction opening to extract printing fluid from the extraction opening. The stream of liquid can be a continuous stream, a uniform stream of droplets, or a non-uniform stream of droplets. The extracted printing fluid can merge with the extraction fluid to be carried to a printing surface for deposition. The stream of extraction fluid can be intermittently charged to intermittently extract printing fluid such that selective portions of the stream do not extract printing fluid.