in direction so that any ink seeping into the tube 26 is very unlikely to leak out of the inlet opening 25 even if the cartridge is rotated through different orientation during transport for ink in the lower section of the tube 26 to reach the opening 25 the cartridge needs to go through a precise sequence of rotations in different directions the risk of this happening by chance during transport and handling is negligible the air inlet tube 26 incorporates an air expansion chamber 27 the cartridge is expected to be exposed to a wide range of temperatures u2014 approximately 35 u00b0 c any ink trapped in the line 26 can be forced to the opening 25 by the increased air pressure the air expansion chamber 27 is relatively large compared to the tube 26 and so has more capacity to accommodate an expanding gas the inlet membrane 16 and the associated chamber 29 is smaller than that of the ink outlet 23 and 24 respectively this accounts for the high rate of ink supply required by the pagewidth inkjet printheads whilst also filtering the ink that leaves through the outlet 3 the large diameter filter 23 and associated chamber 24 means that the filter surface area is.