Patent ID: 8807684

Claim:
A method of identifying defective nozzles of a printhead having one or more ink planes, each ink plane comprising at least one row of nozzles supplied with a same ink, the nozzles in one ink plane being nominally divided into a plurality of neighbouring cells, each cell comprising a set of neighbouring nozzles, said method comprising the steps of: instructing each nozzle in one ink plane of the printhead to print a respective coded line pattern, each coded line pattern being represented by a column of printed pixels and absent pixels, the coded line patterns being defined by first and second coding schemes, the first coding scheme encoding a position of each nozzle within its respective cell and the second coding scheme encoding a position of each cell within its respective ink plane, firing each nozzle of the ink plane to print a test pattern comprising a plurality of neighbouring coded line patterns; imaging an area of the test pattern to obtain an imaged test pattern; decoding the imaged test pattern using the first and second coding schemes; and identifying the defective nozzles using the decoded imaged test pattern.