Printing device and printing method

A printing device which performs printing in an inkjet scheme, comprising:

• a head unit, including a nozzle row in which a plurality of nozzles for ejecting ink drops of ultraviolet curing ink onto a medium is lined up;
• a main scan driver, driving the head unit to perform a main scan operation of ejecting ink drops while moving along a main scan direction which is predetermined;
• a sub scan driver, relatively moving the head unit with respect to the medium along a sub scan direction perpendicular to the main scan direction;
• and
• a controller, controlling the main scan operation of the head unit,
• wherein, in the nozzle row of the head unit, the plurality of nozzles is lined up along the sub scan direction,
• the head unit performs printing on the medium in a multi-pass mode for performing multiple times of the main scan operation on a same area of the medium, and performs the main scan operation corresponding to each of a predetermined N-number of printing passes on the same area of the medium, wherein N is an integer of three or greater,
• the controller sets at least a density of printing to be performed in a k-number of last printing passes of the N-number of printing passes to be performed on the same area of the medium, so as to be lower than a density of printing to be performed in the (N−k)-th printing pass, wherein k is an integer which is equal to or greater than 1 and is less than N and
• in a case where a direction from a nozzle of the nozzle row of the head unit for ejecting ink drops in a first printing pass of the N-number of printing passes toward a nozzle for ejecting ink drops in a N-th printing pass is referred to as a head rear end side, the controller sets a density of printing to be performed by a plurality of individual nozzles of the nozzle row of the head unit for ejecting ink drops in the (N−k+1)-th printing pass, so as to gradually decrease toward the head rear end side.