US Patent 10953662 Inkjet printing device and print defect detection method

The present application discloses an inkjet printing device in which a nozzle that caused a print defect, such as an ejection failure, is reliably identified by a simple process even when an end of a test pattern is not recorded. In a configuration example of the inkjet printing device, a test pattern TPat to be printed for identifying a recording head nozzle that caused a print defect consists of an ejection failure detection pattern DPat and a position detection pattern PPat. The position detection pattern PPat consists of a position mark PM4 and pairs of position marks (PM1 and PM1; PM2 and PM2; and PM3 and PM3) symmetrically arranged with respect to the position mark PM4 in a sheet width direction. Each position mark consists of three linear patterns having the same length and disposed at equal intervals. Moreover, the position detection pattern PPat is configured such that linear pattern length decreases with increasing distance from a center position mark.