US Patent 11167547 Printing apparatus, and a deviation amount calculating method therefor

A printing apparatus for printing on a printing medium transported includes the following elements. A print head including a plurality of print head modules, a printing controller for controlling printing of a testing chart by selecting a reference print head module to provide a reference for recording positions, causing the reference print head module to print a reference chart, and causing one of the print head modules shifted relative to the reference print head module to print a comparison chart, a scanner for acquiring testing image data, an image processor for creating an extract reference chart, creating an extract comparison chart, and creating a composite testing chart by superimposing these charts, and a deviation amount calculator for calculating a deviation amount based on the composite testing chart.