One of the key differences between
fountain pens and
ballpoint pens is how they are filled. While ball
point pens are essentially a fancy holder for a refill, one can
replace only the
ink in an empty fountain pen. The process by which
this happens has evolved in the
century-plus of fountain pens.
They two key methods are either by cartridge or bottle, the latter being the mark of a
"self-filling" pen. Cartridges have only become common relatively
recently (say, the last thirty years or so), and are generally held in
lower esteem than self-filling pens. More on that in a moment.
The earliest fountain pens were filled with an eye dropper. The
"section" (holding the nib and the feed) could
be unscrewed, and an eye dropper would be used to transfer ink from a
bottle to the pen. This got the job done, but was neither neat nor
convenient.
Gradually, mechanisms to allow the pen to suck up its own ink
evolved. I would say there are two primary classification for post-eye
dropper filling systems: bladder (or "sack") based, and piston
based. Sack based pens have a small rubber or plastic sack inside of
the barrel. The sack is somehow compressed, expelling its contents
(air), then released. A vacuum is created, and, if the nib is in ink
(or water), it is pulled into the sack.
The earliest pens used a variety of means to compress the sack. One of
the more unique methods were pens that had a hole for a user to blow
in to (increasing the pressure in the barrel, compressing the sack).
However, what proved to be the best way was for a pressure bar to
somehow be manipulated to press against the sack. The earliest ones
had a slot for a coin or a match stick.
Eventually, two methods evolved that allowed the pen to be
self-sufficient. One was the lever-filler, perhaps the image most
people have of a fountain pen. A lever on the side of the pen would be
pulled out. This pressed the pressure bar against the sack. Replacing
the lever released the pressure bar, allowing the sack to expand. This
can still be found on pens today (though they are typically quite
expensive).
The other method was the button-filler. Under the blind cap would be
a button. Pressing the button bowed the pressure bar, compressing
the sack. Release the button, the pressure bar straightens, and the
sack expands. Though this worked, it typically was higher maintenance
than the lever-filler. This has faded.
There were variations on this, including the:
- Vacumatic filler A diaphragm was moved in and
out, pulling ink in the barrel itself. Essentially the same as a sack
in principle, it allowed more ink to be held.
- Touchdown Filling was accomplished by pulling out
a tube, increasing the volume of the barrel, which compressed the sack.
- Snorkel Similar to the Touchdown in design, a
small tube extended out the front of the pen. The nib did not actually
touch the ink. Ingenious, but quite temperamental.
All of these had some success, though they were somewhat proprietary,
and brought with them some issues in maintainability.
The "final" variation was introduced on the later Parker
51s: the areometric. Rather than manipulating the pressure bar
through some external means, the front section of the pen would
unscrew, revealing the sack and pressure bar. The pressure bar could
then be squeezed directly. This was a fairly simple and reliable
arrangement. It was first introduced in 1948, and, provided there was
no obvious abuse, such a pen is likely to be working today.
Generally speaking, sack-based filling systems have fallen out of
favor for all but the very high-end fountain pens. In general, the cost
of developing and maintaining such a system has proven to be too
expensive.
The other primary self-filling method was the piston
filler. Introduced in the fifties, the rear end of the pen was a
knob. Turning the knob out would cause a piston to plunge down the
barrel, expelling whatever was in the pen (air or ink). Turning the
knob the other way would create a vacuum, pulling in ink if the nib
were dipped in a bottle. This has proven to be an effective and
reliable filling system, and installed on many medium-to-high end
fountain pens--probably the second most common filling system
available today.
The first? Most low-to-medium fountain pens use a cartridge
arrangement. A sealed cartridge of ink is pushed into the section,
providing the ink supply. In most cases, a converter is available that
allows ink to be drawn from a bottle. These are generally derivatives
of either an areometric or piston system.
Of course, this is by no means an exhaustive list--many other ideas
have been tried. Parker once made the 61, which made other
"self filling" pens look quite manual. The back end was simply dipped
in ink, and capillary action drew ink into the pen. More recently,
Pelikan created the "Level" system. The pen "docked" with a special
bottle that squirted ink into the pen.
Among collectors, self-filling pens are held in the highest esteem,
either because it is a vintage pen, or for the retro feel. Converters
hold second place, with cartridges tolerated--it's at least better
than a ball point.
Sources:
http://www.ettnet.se/~boris/parkerindex.html
The Zoss pen list