An image forming system configured to eject ink onto a sheet conveyed in a first direction including a first head including a plurality of first ejection ports configured to eject the ink; a second head including a plurality of second ejection ports configured to eject the ink; an input part configured to be input ejection port information on the plurality of first ejection ports and the plurality of second ejection ports; and a controller configured to control ejection of the ink from the first ejection ports and the second ejection ports based on the ejection port information.