A method of manufacturing an ink cartridge for use in an ink jet recorder, comprising the step of providing an ink bag having a top end, and a bottom end below the top end, the top end being open and the bottom end having an ink feed port therein; moving the ink bag from a first position near a top edge thereof and positioning the ink bag in a vacuum chamber; depressurizing the vacuum chamber; charging a selected quantity of ink into the ink bag; sealing the open end of the ink bag at a second position below the first position; pressing the sealed portion of the ink bag to a selected thickness with press plates; sealing the bag in the pressed position at a third position below the second position; and cutting the ink bag between the second and third positions.