Patent ID: RE41609

Claim:
A liquid ejection inspecting method for an ejection nozzle array including plural ejection nozzles comprising a printhead for ejecting liquid wherein said plural ejection nozzles extend in a first scan direction , said liquid ejection inspecting method comprising the steps of: photographing said ejection nozzles in said ejection nozzle array , with a pickup device to output image data; analyzing , using processor, said image data to output analysis result information; and judging whether an ejecting state of said ejection nozzles is acceptable or unacceptable according to said analysis result information ; , moving one of said printhead and said recording material relative to a remaining one thereof at a small adjusting shifted amount in said first scan direction, said adjusting shifted amount being equal to a pitch between an unacceptable nozzle of which said unacceptable state is judged and an acceptable nozzle close thereto and of which said acceptable state is judged among said ejection nozzles, and causing said acceptable nozzle to eject said ink instead of said unacceptable nozzle, so as to compensate for lowering of image quality due to said unacceptable state; and recording images to recording material based on whether an object which prevents said liquid from passing through a discharging port of said ejection nozzle is stuck on said ejection nozzle wherein the unacceptable states include states where an object is stuck on a nozzle arrangement surface near to the ejection nozzles, where the object is stuck on an inner surface of the ejection nozzles, where the object is stuck and extends across an edge of the ejection nozzles, where the object is located inside the ejection nozzles, and where the object is stuck to cover the whole of the ejection nozzles, and wherein said judging step includes comparing said difference with a predetermined threshold value adapted to said pattern recognition process, judging said acceptable state if said difference is equal to or less than said threshold value, and judging said unacceptable state if said difference is more than said threshold value .