|Filling Instructions: Bulb-Fillers|
The bulb-filler, which might better be termed the bulb-and-breather-tube filler, is the most basic form of a filling system with numerous more complicated variants.
These pens are filled by repeatedly squeezing the bulb. With each squeeze, air is expelled through the breather tube and out the feed. Each time the bulb is released, ink is drawn in. This is one of the simplest and most elegant filling systems, whose only real drawback is a slight awkwardness in emptying. This entails repeated slow squeezes of the bulb, expelling the ink from the nib and feed drop by drop.
Prominent examples of bulb-fillers include the Postal, various economy-line Wahl-Eversharps (a Bantam is shown above), and the French Stylomine. Most pump-fillers, including Vacumatics, Dunns, and Ink-Vues work on the same principle, either adding a device to squeeze the bulb or substituting some other means of intermittently pressurizing the barrel (typically, a reciprocating plunger).