The Rollerball pen is known for writing smoother and allows you to use less pressure when you’re writing. The reason for this is that the rollerball pen uses a liquid-based ink (similar to Fountain Pen Ink). Because of this, the ink can take longer to dry on the page. However, because you don’t need to use a lot of pressure for the ink to flow freely, it’s great for long writing sessions (students, authors, journaling).
It’s important when you’re using rollerball pens to keep the cap of the pen on when not in use as this keeps the pen from drying out.