English: Example of inkjet printer air vent channels, on the top of an Epson ink tank.

The channels are required to allow air to enter when ink is sprayed out by the printhead. The yellow strip is peeled off by the user before inserting the tank into the printer, and opens the ends of the channels to the atmosphere. If the yellow strip is not removed, the air pressure imbalance prevents the ink from spraying out the printheads.

The channels are molded into the top of the plastic tank as a series of ridges and valleys, and the blue adhesive label seals across the all the ridges to make the valleys into long continuous tubes. These tubes allow air to seep into the cartridge while the length of the long tube helps to slow moisture evaporation out of the tank. However once the yellow strip is removed, the slowed evaporation begins and the cartridge will evetually dry out and fail. This drying could be stopped by reapplying tape where the yellow strip is located, but for this printer would require removing the tank from the printer, which Epson Stylus printers do not allow until the tank is completely empty.

This tank has five separate ink compartments for more accurate color printing than just four colors can provide. During manufacture, the ink tank is filled through the two large holes in each tank compartment, and then the blue/yellow label is applied to seal the tank until use. The blue label says "Do not remove" on the side, because peeling the label off completely destroys the tubes and directly exposes the compartment fill holes to evaporation. The ink would quickly dry up and fail with the blue label removed.