When print data PD generated by applications 100 is supplied to a graphics library 110 in an order of describing objects, the graphics library 110 makes correspond print data PD to objects so as to store print data PD in a metafile 120. After print data for one page has been stored in the metafile 120, the metafile 120 is retrieved. Thus, print data PD is reconstructed for each band. A printer driver 130 converts reconstructed print data PD into the PDL data PD′ so as to transfer the PDL data PD′ to an output apparatus 2. A decomposer 140 does not generate intermediate format data and directly develops the PDL data PD′ in a band buffer 22. An output device 24 reads raster data RD from the band buffer 22 so as to print an image on a paper sheet.