An image forming apparatus includes a recording head configured to jet liquid droplets; and a sheet supporting unit configured to support a sheet that is conveyed facing the recording head, in such a manner that a predetermined gap is provided between the sheet and the recording head, the sheet supporting unit including fixed ribs and movable ribs, wherein the movable ribs are movable within a range such that a top edge of each of the movable ribs supporting the sheet does not exceed a top edge of each of the fixed ribs supporting the sheet.