To effectively remove ink from a surface and suppress increase in manufacturing cost and consumption of treatment liquid.

A printer includes four heads 1 discharging ink droplets, a head 2 discharging precoat liquid droplets, a preliminary discharge execution part and a cleaner unit. Based on a mode of preliminary discharging one or a plurality of precoat droplets from the head 2 so as to exceed total amount of ink droplets discharged from four discharge ports superposed along an auxiliary scanning direction and minimize a difference with total amount of the ink droplets, the preliminary discharge execution part executes preliminary discharge for preliminary discharging the precoat liquid droplets from a discharge port of the head 2 on a surface 8a of a carrying belt 8 and landing ink droplets from discharge ports of the heads 1 on a position where the precoat liquid droplets are landed. The cleaner unit removes the ink and precoat liquid adhered to the surface 8a of the carrying belt 8.