Automatic printing adjustment method for page-width array printing device

An automatic printing adjustment method for a page-width array printing device, the page-width array printing device comprising a printing module, a scanning module and a print region, the printing module comprising a plurality of inkjet head structures, each inkjet head structure comprising a plurality of nozzles, the automatic printing adjustment method comprising steps of:

• (a) allowing the printing module to print a print medium placed on the print region to obtain a printed image and allowing the scanning module to scan the printed image of the print medium;
• (b) transmitting the printed image from the scanning module to a processor;
• (c) performing a noise eliminating operation, a tilt calibration operation, a ROI (region of interest) selecting operation, a horizontal detection operation and a vertical detection operation on the printed image by the processor;
• and
• (d) feedback a calibrating result from the processor to the printing module, so that printing conditions of the nozzles of the respective inkjet head structure are adjusted according to the calibrating result.