Abstract: An air flow restriction device relates to an ink jet printhead enclosure with body, a load supportable moveable lid with an opening disposed on the body, and a chamber within the body. Continuous web media is disposed in the chamber with at least one ink jet printhead located above the continuous web media within the chamber. A high efficiency air filter with a fan is located within the opening of the moveable lid and the filter with fan flows continuous clean filtered air into the enclosure, bathing the ink jet printhead and the continuous web media in clean filtered air. An air flow restriction device is placed in the side of the chamber below the continuous web media creating positive pressure in the chamber when the fan and filter floods the chamber with the clean filtered air, thereby reducing particle contamination in the chamber by a factor of at least ten.