At S702, a memory area to be used for transfer processing is obtained in accordance with the currently empty area. In the stage immediately after the start of this flow, it is possible to simultaneously obtain the memory area corresponding up to three pages at the maximum. Then, the count value corresponding to the obtained number of pages is set to the page counter. In a case where the memory area corresponding to a plurality of pages is obtained, the subsequent processing advances in parallel for a plurality of pages along the way, but for convenience of explanation, the processing for one page is explained in this flow. Then, how the parallel processing advances for a plurality of pages is explained by using a timing chart separately.

At S703, the compressed binary image data (hereinafter, simply called “compressed data”) of a processing-target page is read from the large-capacity storage device 140 and stored in the RAM 104. At S704 that follows, the binary image compression/decompression unit 211 is instructed to decompress the compressed data of the processing-target page. Upon receipt of the instructions, the binary image compression/decompression unit 211 reads the compressed data of the processing-target page stored in the RAM 104 and performs decompression processing. The binary image data obtained by the decompression processing (hereinafter, simply called “decompressed data”) is stored in the memory area within the RAM 104 obtained at S702 (or in a dedicated image memory) after being subjected appropriately to predetermined image processing, such as rotation, movement, scaling, and combination, in accordance with the printing information and user instructions via the operation unit 120.