Structure of a fountain pen

Structure of a fountain pen
last up date 2004/10/20

The name of each part of a pen

Nib feed
The function of a nib feed is to let ink flow smoothly and continuously. A good nib feed is essential.

Structure of a nib feed

A plastic nib feed has a capillary groove on the back where the ink flows and an air vent hole on its belly where air comes in to replace the ink. Also there is an "expansion chamber" (comb cuts) which prevent the ink from blotting. Ink flows through the center hole of the nib feed and air goes to the reservoir. Then ink is drawn out by capillary action.

1. Leads ink to nib tip.
2. Prevention of ink blotting.
3. Closed up tightly in the cover. Back of the nib tip is always moistened and enables smooth start of the writing.

Picture by vertical cut

1. air exchange groove
2. body
3. ink slit
4. ink lead slit
5. air vent groove
　

Ink blotting

The most common problem of a fountain pen is ink blotting (pen periodically lets out huge drops or blots of ink during writing) or ink flooding (point consistently lays down too much ink). Ink blotting is caused by the difference of temperature and/or air pressure between inside and outside of a fountain pen. Therefore it often happens in the winter times, when the cold air in the reservoir or ink cartridge is warmed by the hand and expanded too quickly which push out too much ink, or on the airplane, when the air pressure gets low.

Automatic ink control

The nib feed developed by the Platinum Fountain Pen Company has automatic ink flow control so ink blotting and flooding never occur. It functions as follows: Ink in the ink cartridge flows out through the center of the nib feed by the capillary action. Air goes into the ink cartridge from the air vent groove through the expansion chamber. The air inside expanded by the warmth of the hand pushes out the ink and ink is stored in the expansion chamber. The air in the expansion chamber is pushed out from the air vent groove on the belly side and so ink is stored in the expansion chamber. As the stored ink in the expansion chamber blocks air going in, the inside of the ink cartridge becomes vacuum and flow of the ink stops. Meanwhile, ink in the expansion chamber flows out through the capillary action while writing and stored ink is expended gradually. Then again air goes in, capillary action takes place and ink flows. Also there is an automatic control system which stops the flow of the ink into the expansion chamber when it's full. Therefore no ink blotting or no skipping of ink ever happens until the end regardless of the temperature and/or air pressure differences.