Balpen

Balpen, or ballpoint pen, is a writing instrument that dispenses ink through a small rotating ball at its tip. The ball, usually made of brass, steel, or tungsten carbide, sits in a replaceable socket and transfers ink from an internal reservoir to the writing surface as it rolls. The ink is typically oil-based or gel-based, designed to dry quickly and resist smudging. Ballpoint pens are available in a range of tip sizes, commonly from 0.3 mm to 1.2 mm, which determine line width and writing feel. Most balpens are designed to be low maintenance, with either disposable ink cartridges or refillable reservoirs; retractable (click-activated) designs are common for everyday use, while capped variants are preferred in some cultures or for archival writing.

Invention and development: The modern ballpoint pen traces its development to László Bíró, a Hungarian journalist, who in the 1930s, with his brother Georg, devised a pen using a quick-drying ink and a rotating ball to control ink flow. They patented the design in 1938, and during the 1940s the technology spread worldwide, with brands such as Bíró, Parker, and later Bic popularizing inexpensive models. The term "biro" became a generic name for ballpoints in several languages.

Usage and impact: Balpens are among the most common writing instruments worldwide due to their low cost, reliability, and ease of use. They are used in education, business, and daily life, and come in numerous colors and capacities. Environmental considerations include plastic bodies and ink cartridges, prompting recycling and refill options in many markets.