US Patent 8002378 Nozzle testing apparatus, nozzle testing method, and test program

A nozzle testing apparatus and method that tests whether recording liquid is ejected from a plurality of nozzles provided in a print head using changes of voltages between measurement terminals that are generated in accordance with ejection of the charged recording liquid. The apparatus comprises a voltage applying unit capable of charging the recording liquid to a predetermined electric potential level by applying a voltage between measurement terminals in a predetermined direction, a head driving unit capable of ejecting the charged recording liquid from the nozzles, a voltage change acquiring unit that acquires the change in voltage between the measurement terminals generated in response to the ejection of the recording liquid, and an ejection checking unit that determines whether the recording liquid is ejected from each nozzle in the plurality of nozzles by using the acquired changes in voltage.