- Reservoir: Holds the supply of ink inside the body of the pen.
- Tip Mechanism: Transfers the ink to the paper, using a metal nib in fountain pens or a tiny rolling ball in ballpoint pens.
Flow Control: Guides the ink evenly so it does not leak or dry up inside the pen.
- Fountain Pen: Uses a metal nib and water-based ink that flows from an internal reservoir through capillary action.
- Ballpoint Pen: Uses a small rotating metal ball and thick, oil-based ink that dries fast.
- Gel / Rollerball Pen: Uses water-based gel ink for a smooth, bold line similar to a fountain pen but with the ease of a ballpoint. [1, 2, 3, 4]