How Does Ink Come Out of Pens?

All modern pens have a few things in common. They all have an ink cartridge, a tip and a shaft to hold the whole thing together. As you write, gravity pulls ink toward the tip, which transfers it to the paper. The main difference between different pens is the type of tip they have.

Ballpoint and rollerball pens both work the same way. At the tip of the pen, there is a small metal ball. Directly behind that ball is the cartridge, which coats the back of it with ink. When you write, it causes the ball to spin. As the ball spins, it spreads ink on the page.

Felt-tipped pens and markers are even simpler. A felt pen has a soft tip that absorbs ink. When you write, some of that ink gets rubbed against the page, leaving a mark. It is like dragging a wet towel along the floor. Some of the water from that towel gets on the floor, leaving a trail.

One of the most interesting modern pens is the space pen. Space pens were developed for astronauts to write in zero gravity. They are like normal ballpoint pens but with one important difference: pressurized cartridges. The pressurized cartridge means that a space pen can write in zero gravity or upside down. The extra pressure inside the cartridge keeps the ink flowing.

Resources

• Pen Resources