typebar

Typebar refers to a metal lever in a traditional mechanical typewriter that carries a raised character on its end. When a key is pressed, its corresponding typebar pivots forward and strikes ink from the ribbon onto the paper, forming the printed character.

Construction and operation: Typebars are arranged in a type basket and linked to the keyboard through a system of linkages. Each bar bears the character as a raised type slug on its end. On keystroke, the bar swings upward, the ribbon is pressed between the slug and the paper, and the character is printed. The bar returns to its resting position under spring tension, and a separate mechanism advances the paper after each strike. The arrangement of bars and their mounting influences character spacing and typing speed.

History and variants: Typebar mechanisms were standard in most early and mid-20th-century mechanical typewriters. They require precise alignment and are subject to wear and ink build-up. With the advent of electric typewriters, different printing mechanisms were introduced. The IBM Selectric, introduced in 1961, used a rotating typeball (type element) instead of a fixed array of typebars, with a hammer striking the selected character against the ribbon. This design represented a major shift away from traditional typebars.

Legacy: Today typebar-based machines are primarily of historical interest and are preserved by collectors and museums. Maintenance focuses on cleaning, keeping the type slugs free of ink, and ensuring the return springs and type basket operate smoothly.