Ballpoint pens have an internal reservoir filled with an ink of higher viscosity, the rolling action of a small metal sphere will dispense the ink over the paper. The ink dries instantly, they are reliable, inexpensive, need no maintenance and can be found anywhere. Ballpoint pens are the most popular writing tools of our modern times and they've replaced fountain pens almost completely.
Ballpoint pens appeared in relation to the combined action of several factors like experience in the pen industry, modern chemistry and the 20th century technological advance. History mentions several attempts to design ballpoint pens since the 17th century when Galileo Galilei patented the first model. The multitude of imminent problems made it impossible for the ballpoint pens to be widely produced then, but things were to change some hundreds of years later.
On October 30, 1888 John J. Loud patented the first ballpoint pen, which had just a small rotating steel ball. This first model opened the perspective for ballpoint pens but it couldn't be used for paper as it wasn't rough enough to move the ball. It was effective only on hard, rough surfaces like leather, and due to this inconvenience it wasn't produced on large scale. During the first part of the 20th century there was a general interest taken in improving writing tools, and at the time a lot of research and effort was invested in the pen industry.
Several new ballpoint pens appeared in 1907, 1910 and 1916. In the case of these first models ink was kept in a thin reservoir blocked by a small metal ball. Their problem was that they didn't spread the ink uniformly over the paper. If the ball socket was tighter than it should, the ink wouldn't flow, and on the contrary, if it was too large then the ink would leak. None of these problems could be corrected at the time. If some of the inventors managed to eliminate the problem, the production costs were so high that the investment wasn't worth making.
Laszlo Biro, a Hungarian editor, noticed that the ink used for newspapers dried very fast, then he had the incredible idea of using it to create a pen. He first tried the ink with classical fountain pens but the combination wasn't a success, hence, Biro turned to his brother who was a chemist. Together they began designing new types of pens, and on June 15, 1938 Biro patented his idea and began developing his business.
Earlier ballpoint pens had leaking problems due to improper ink viscosity and a faulty ball socket, so that there were situations when you had to keep the pen vertically in order to write well. Biro came with innovative ideas, he pressurized the ink and used capillary action solving all flowing problems.