Interpret processing of received PDL data and determination whether a command includes group information are performed. CPUs that are available for processing are searched, and based on the group information and information about divided objects, to which CPU each processing of the divided objects is to be assigned is determined. The CPUs to which the processing is assigned convert the received data into intermediate data suitable for processing in a printing unit. The plurality of CPUs are instructed to perform image generation processing based on the generated intermediate data in parallel for each processing unit.