Patent ID: 8733877

Claim:
A discharge defect detection method comprising: an image reading step of reading an image recorded on a medium to acquire read data of the image, the image being recorded on the medium by discharging liquid from a plurality of nozzles based on image data while moving a liquid discharge head having a nozzle row, in which the plurality of nozzles is aligned, and the medium relative to each other; a visual characteristic correction step of performing a filtering process corresponding to human visual characteristics for the read data acquired in the image reading step; a nozzle position matching step of specifying a correspondence relationship between a pixel position of the read data and a nozzle position in the liquid discharge head from a mark that is recorded in a margin outside an image region on the medium by a nozzle set in advance; a resolution conversion step of converting data, for which the filtering process has been performed in the visual characteristic correction step, into data having a nozzle resolution of the liquid discharge head using the correspondence relationship specified in the nozzle position matching step; a reference data generation step of generating reference data, which indicates a reference image, from the image data or the read data acquired in the image reading step; a reference data storage step of storing the reference data generated in the reference data generation step; and a defect detection step of detecting a discharge defect of a nozzle in the nozzle row by comparing the read data for which nozzle resolution conversion has been performed, which is generated by performing the filtering process in the visual characteristic correction step and a process for conversion into the nozzle resolution in the resolution conversion step for the read data generated from the image read in the image reading step, with the reference data for which nozzle resolution conversion has been performed, which is generated through the filtering process corresponding to the visual characteristics and the process for conversion into the nozzle resolution of the liquid discharge head.