Printing device and printing method

A printing device comprising:

• a printer, which includes a plurality of nozzles;
• a discharge detection sensor configured to detect an amount of ink discharged from the plurality of the nozzles;
• and
• a nozzle combination calculator configured to determine a final nozzle combination for each pixel column on a substrate based on discharge rates of the plurality of the nozzles,
• wherein the nozzle combination calculator includes:
• an average value calculator configured to set a usable nozzle group for each pixel column of the substrate among the plurality of the nozzles;
• and
• a nozzle combination determiner configured to determine the final nozzle combination corresponding to each pixel column by using a moving average value of nozzle discharge rates of the usable nozzle group set for each pixel column,
• wherein the nozzle combination calculator further includes a nozzle discharge calculator configured to:
• calculate a first average value (M) of the discharge rates of the plurality of the nozzles,
• calculate an average nozzle discharge rate (m) of the usable nozzle group set for each pixel column, and
• calculate and record an average value ratio (m/M).