An image-forming device has a carriage, a conveying unit, a controller, and a detector. The carriage has recording elements to form dots on a sheet having an edge extending in the subscanning direction. The carriage is movable in a main scanning direction orthogonal to the subscanning direction. The conveying unit conveys the sheet in the subscanning direction by a predetermined distance when the recording unit moves in the subscanning direction. The controller sequentially selects a first distance n times (n: a natural number) as the predetermined distance, and selects a second distance as the predetermined distance after the n times of selection of the first distance. The second distance is longer than the first distance. The detector detects the edge of the sheet only after the sheet is conveyed by the second distance.