An ink jet printer including a carriage which is movable relative to a sheet of paper, a recording head which is mounted on the carriage and records an image on the sheet by ejecting a droplet of ink toward the sheet, one or more ink tanks which store the ink or inks to be supplied to the recording head, a buffer tank which is mounted on the carriage, and one or more ink flow passages in which the inks are supplied from the ink tanks to the recording head via the buffer tank. The buffer tank has, at a height position higher than a height position where the recording head is provided, one or more air buffer chambers which accommodate respective amounts of the inks, and collect air bubbles produced in the ink flow passages.