A print unit memorizes image data to be output to a page of recording media at a register as jetting data in an order of storing a plurality of image data of one line in page memory, wherein each of the image data of one line is memorized at the register in an order of storing the plurality of image data of one dot, in case when a conveyance direction of recording media is normal; and memorizes the image data to be output to the page of the recording media at the register in the order of storing the plurality of the image data of one line, wherein each of the image data of one line is memorized in a reverse order to the order of storing the plurality of the image data of one dot, in case when the conveyance direction is reverse.