Patent ID: 7543904

Claim:
A print head nozzle inspection method for inspecting a nozzle of a print head of a printing device, the printing device including a print head with a plurality of nozzles for ejecting print recording liquid, a print recording liquid-receiving area that is capable of receiving print recording liquid ejected from the nozzles, and a switching module that is used to switch the status of the print head between being at ground potential and being independent from ground potential; said print head inspection method comprising the steps of: (a) at the time of printing, driving the print head to eject print recording liquid while the print head is made at ground potential by use of the switching module; and (b) at the time of a nozzle inspection, generating a predetermined potential difference between the print head and the print recording liquid-receiving area while the print head is made independent from ground potential by use of the switching module, driving the print head to eject print recording liquid onto the print recording liquid-receiving area with the generated predetermined potential difference maintained, performs a nozzle inspection as to whether print recording liquid has been ejected from each of the nozzles in the print head based on results of detecting electrical change in the print recording liquid-receiving area or in the print head.