Kuulakärkikyniä

Kuulakärkikyniä, often referred to as ballpoint pens in English, are writing instruments that utilize a rotating ball, typically made of brass, steel, or tungsten carbide, to distribute ink onto a surface as the pen moves. The ink is usually oil-based and viscous, which helps to prevent it from drying out in the reservoir or leaking uncontrollably. As the ball rotates, it picks up ink from a cartridge within the pen and deposits it onto the paper, creating a line.

The invention of the modern ballpoint pen is credited to László Bíró, a Hungarian-Argentine journalist, who patented his design in 1938. Bíró observed that the ink used in newspaper printing dried quickly and didn't smudge, and he sought to create a pen that used a similar, fast-drying ink. His design featured a small metal ball in its tip, held in place by a socket. Early versions of ballpoint pens existed before Bíró's patent, but they suffered from issues like uneven ink flow and ball sticking.

Ballpoint pens became widely popular due to their reliability, low cost, and convenience. Unlike fountain pens, they do not require special handling or maintenance and can be used on most paper surfaces without bleeding. They come in a vast array of ink colors, tip sizes, and barrel designs, catering to diverse writing preferences and needs. Their widespread use has made them a staple in offices, schools, and households worldwide.