Here are the main differences in a rollerball and ballpoint pen...
Which is right for you?
Some of the main differences are:
1. They each use a different type of ink
2. They each require different pressure on the point to write
3. The “balls” tend to be of different composition.
4. The line characteristics are can be somewhat different
5. Cartridge life is usually different
Inks are different in a handmade rollerball and handcrafted ballpoint pen
Ballpoint pens generally use a thicker oil based ink (in some cases almost waxy). When the ink is rolled across the paper with a ballpoint pen the ink tends to stay on the surface of the paper. There are always exceptions but usually ballpoint pens take more pressure to lay down the ink. Rollerball pens tend to have a more fluid ink (water based ink) that flows easier due to a lower viscosity. The ink in a rollerball pens tends to saturate the paper and not just lay on the surface as a ballpoint.
Different pressures are needed for a rollerball vs. a ballpoint pen
Since the ink if different in each pen slightly different pressure is need to write with each pen. Ballpoint pens with the thicker ink tend to take more pressure to write. This can be great if you write you make carbon copies often. The pressure to write with a good rollerball pen is minimal. Rollerball pens were made to write more like a fountain pen where little or no pressure is required to have the ink flow.
The composition of the balls is often different.
Ballpoint pens tend to use a metal ball at the tip. The metal is often brass, nickel or steel. Better ballpoints pens use stainless steel or tungsten carbide tips. Tips (rollerballs) on high end rollerballs are ceramic which glides across the paper more easily.
The lines the two different pens make can be different
Since more pressure is required on a ballpoint to get the ink to flow the lines tend to be wider (given the diameter of the tips are the same). Rollerballs generally are more capable of producing finer lines.
The life of the ink cartridge can be different in a rollerball vs. a ballpoint
Since the ink of a rollerball is more liquid than a ballpoint and saturates the paper to a greater degree, the lifespan of a rollerball cartridge is generally shorter. Ballpoint cartridges tend to last longer because less ink if put down when writing.