Answer: This is required as a very important step in having stable printing quality.

White ink is easier precipitate than other inks.

•In case without printing more than two weeks, white ink may cause precipitate in ink cartridge or inside of the machine.
•When the ink is precipitated, nozzle clogging occurs and normal drawing can not be obtained.
•Make sure to perform periodical maintenance to avoid precipitation and to keep white ink good condition.