Printing apparatus and printing method

A printing method for a printing apparatus including:

• a nozzle row configured to discharge ink onto a printing medium;
• a main scanning unit configured to change a relative position between the printing medium and the nozzle row in a main scanning direction;
• a first irradiation unit provided on one side, in the main scanning direction, of a reference region in which the nozzle row is provided;
• and
• a second irradiation unit provided on another side, in the main scanning direction, of the reference region, wherein
• at least one of the first irradiation unit and the second irradiation unit is configured to perform irradiation at an irradiation position different from a directly-below irradiation position, the directly-below irradiation position being a irradiation position when irradiation is performed directly below,
• when a distance between a center of the reference region and a center of an irradiation position of the first irradiation unit is a first distance, a distance between the center of the reference region and a center of an irradiation position of the second irradiation unit is a second distance, a distance between the center of the reference region and a center of the directly-below irradiation position of the first irradiation unit is a third distance, and a distance between the center of the reference region and a center of the directly-below irradiation position of the second irradiation unit is a fourth distance,
• the nozzle row, the first irradiation unit, and the second irradiation unit are provided so that the third distance and the fourth distance are different from each other, and
• the printing method comprises a first irradiation unit lighting step for lighting up the first irradiation unit and a second irradiation unit lighting step for lighting up the second irradiation unit so that the following condition is satisfied:
• |the first distance−the second distance|<|the third distance−the fourth distance|.