PURPOSE: To prevent the performance from decreasing and to simplify the resource file control process of an input process part by putting the input process part in operation without being affected by the process state of an output process part.

CONSTITUTION: Attribute information such as the job number of an inputted print resource file is stored in the attribute area 23a of a buffer 23 for print resource file data storage. After a printing process ends normally, internal format data is compared with the attribute information of the used resource file, it is judged whether the file is necessary for a subsequent printing process, and the unnecessary file is erased on the buffer 23 for print resource file data storage. This erasing process can be performed irrelevantly to an input process processor 21, whose process is never affected by the state of the process of an output process processor 25.