A raster image processor (RIP) can process data for one page for each of a plurality of small areas, and handles each individual small area as a display list. Each individual display list holds information required to determine a rendering resolution. The RIP renders a small area including a text object with a high resolution, and a small area which does not include any text object with a low resolution. The RIP renders the respective small areas with the designated resolutions, and temporarily holds the rendering results in a memory for respective small areas. Upon generating a page image, the RIP directly transfers the high-resolution rendering result to a page memory. The RIP transfers the low-resolution rendering result to the page memory with applying an enlarging pixel process to the rendering result.