An image-forming system comprising: an image generator, a band divider, an image shaping unit, an image combiner, a loader, a band memory, an output unit, and a print engine, wherein the band divider is configured to divide image data including N image data pieces (23, 25, 27, 29, 39, 41), received from the image generator, into a plurality of bands (Band 1, Band 2, Band 3, Band 4, Band 5, Band 6, Band 7, Band 8), each having a height and containing divided image data, the image shaping unit is configured to reduce, enlarge, or rotate the plurality of bands and to send the plurality of bands to the image combiner, the image combiner is configured to carry out an N-up process that conducts N-in-1 printing, wherein said N image data pieces (23, 25, 27, 29, 39, 41) being combined in a main scanning direction into one data piece having a final image size to be printed on a single sheet, and to send the combined bands to the loader, the loader is configured to load the plurality of bands into a band memory, and an output unit configured to sequentially output the plurality of bands from the band memory to the print engine at predetermined timing, characterized in that upon performing the N-up process, the band divider is configured for setting ends (31, 33, 35, 37, 43, 45) of the image data pieces as the boundaries of last bands (Band 4, Band 8) of the plurality of bands, and varying the height of the last band, the height of the last bands being lower than the height of the other bands, the band memory includes a main video memory and an auxiliary video memory, the main video memory including a first video random access memory (VRAM1) and a second video random access memory (VRAM2), and the auxiliary video memory including a third video random access memory (VRAM special), and the first VRAM and the second VRAM being configured for storing the plurality of bands excepting the last bands, and the third VRAM being configured for storing the last bands. an image generator, a band divider, an image shaping unit, an image combiner, a loader, a band memory, an output unit, and a print engine, wherein the band divider is configured to divide image data including N image data pieces (23, 25, 27, 29, 39, 41), received from the image generator, into a plurality of bands (Band 1, Band 2, Band 3, Band 4, Band 5, Band 6, Band 7, Band 8), each having a height and containing divided image data, the image shaping unit is configured to reduce, enlarge, or rotate the plurality of bands and to send the plurality of bands to the image combiner, the image combiner is configured to carry out an N-up process that conducts N-in-1 printing, wherein said N image data pieces (23, 25, 27, 29, 39, 41) being combined in a main scanning direction into one data piece having a final image size to be printed on a single sheet, and to send the combined bands to the loader, the loader is configured to load the plurality of bands into a band memory, and an output unit configured to sequentially output the plurality of bands from the band memory to the print engine at predetermined timing, characterized in that upon performing the N-up process, the band divider is configured for setting ends (31, 33, 35, 37, 43, 45) of the image data pieces as the boundaries of last bands (Band 4, Band 8) of the plurality of bands, and varying the height of the last band, the height of the last bands being lower than the height of the other bands, the band memory includes a main video memory and an auxiliary video memory, the main video memory including a first video random access memory (VRAM1) and a second video random access memory (VRAM2), and the auxiliary video memory including a third video random access memory (VRAM special), and the first VRAM and the second VRAM being configured for storing the plurality of bands excepting the last bands, and the third VRAM being configured for storing the last bands.