Each of a first image processing unit and a second image processing unit is configured to generate print data to be used by a printing unit based on image data generated by a controller. The controller comprises a transmission control unit configured to select, based on a sheet size which is a print setting corresponding to a print job as a condition, one of first transmission control of controlling a transmission unit to alternately transmit band data included in first image data and band data included in second image data and second transmission control of controlling the transmission unit so that the band data included in the second image data will be transmitted after the band data included in the first image data has been transmitted.