Feed

The feed of a fountain pen is the component that connects the nib of the pen with its ink reservoir.

It not only allows the ink to flow to the nib (in what is often described as a "controlled leak") but also regulates the amount of air flowing backwards up to the reservoir to replace this lost ink.

It does this through the use of a series of narrow channels or "fissures" that run down its lower edge. As ink flows down these fissures, air is simultaneously allowed to flow upwards into the reservoir in an even exchange of volumes. The feed allows ink to flow when the pen is being put to paper but ensures ink does not flow when the pen is not in use. The feed makes use of capillary action; this is noticeable when a pen is refilled with a brightly coloured ink. The ink is taken up and into the feed by way of capillary action (and is often visible in clear demonstrator pens), but is not dispensed onto the paper until the nib makes contact.

How the feed is shaped may determine the wetness and flow of a particular pen. For this reason, feed material alone may have a significant effect on the way two pens of the same nib size write.

Pen feeds are crucial to preventing ink from dripping or leaking. A pen with a misconfigured feed might fail to deposit any ink whatsoever.