by David E. Silber
There are a wide variety of mechanisms that have been used—are still used—to draw ink into the fountain pen. Some are:
1. Dip pens had no reservoirs, and had to be dipped constantly to refill the nib with ink. (We used those pens when I was in elementary school, and so my left-hand and the paper were constantly smeared with ink.) During the 1800s, pen manufacturers tried a number of systems, but even a sophisticated one using a glass cartridge to hold ink (patented by Eagle in 1891) didn't work very well.
2. The first pens to actually hold ink internally--and worked well-- unscrewed behind the nib, and were filled by an eye-dropped, then screwed tightly back together. Messy, but they held a lot of ink, and are collectively called “eye-dropper pens.”
3. Conklin, about 1903, patented a mechanism that used an external crescent welded to a bar inside the barrel. When the crescent was pressed down, the bar emptied the sac inside of air, and when released, gravity sucked ink into the sac. Ingenious but bulky.
4. About 1911, Sheaffer patented a mechanism that used a lever. When opened, the lever depressed a bar, which depressed the rubber sac inside the pen barrel, emptying the air. When released, suction drew ink up into the bladder, or sac. The lever method of filling is still found on some modern pens because it is simple and relatively reliable.
5. This led to a scramble to find other ways to fill the pen. Some of them predate the lever-fill mechanism of Sheaffer, and some came after. For example just a bit later, Parker introduced a filling mechanism that used a button at the end of the pen barrel which depressed a bar and the sac within. A highly sophisticated system, but surprisingly easy to service. Earlier systems used a "coin fill" method, whee a penny would be pressed into a slot in the barrel to depress the pressure bar. Or a "plug" that did the same thing.
6. Other filling systems used a plunger within the barrel (without a rubber sac) to expel air, and then to draw up ink when the plunger is pulled or pushed back.. Twist piston fillers are still popular on some current pens, especially German ones.
7. Variations included a sort of hybrid plunger called a “vac filler” by Parker that was half sac, half plunger. Though it held more ink then a rubber sac, it is difficult to service. Another is a “snorkel” arrangement that Sheaffer introduced, where an extending tube goes into the ink bottle to kept he pen nib dry. The variations were legion.
8. Since about 1960, most pens use filled cartridges that fit into the pen’s feed, and are discarded when empty. They are convenient and clean, though a a problem is that some manufacturers no longer make cartridges tofittheir pens. For some (e.g., the Waterman CF) a “converter” fits into the pen where the cartridge would but allows the pen to be filled from an ink-bottle.