An image forming apparatus includes a recording head including a plurality of printing elements each of which offsets at least in a auxiliary-scanning direction one another and ejects droplets toward a recording medium. The image forming apparatus further includes a main scanning unit configured to scan the recording head, relative to the recording medium, in a main scanning direction perpendicular to the auxiliary-scanning direction. The image forming apparatus still further includes a auxiliary-scanning unit configured to scan the recording head, relative to the recording medium, in a main scanning direction perpendicular to the auxiliary-scanning direction. The image forming apparatus still yet further includes a controller configured to control the printing head, the main scanning unit and the auxiliary-scanning unit to form dots in rows arranged in the auxiliary-scanning direction at a first predetermined interval, and columns arranged in the main scanning direction at a second predetermined interval while performing main scans and sub-scans repeatedly. The controller controls the printing head, the main scanning unit and the auxiliary-scanning unit to form first dots in an area of the printing medium at first alternate columns by a first main scan, and to form second dots in the area by a second main scan at second alternate columns different from the first alternate columns. The second dots are shifted, relative to the first dots, a first predetermined distance smaller the first predetermined interval.