Typebar printer
A printing mechanism where every print position owns a bar carrying the full character set, raised into place and then struck against the paper.
The idea came straight from the typewriter, turned ninety degrees: instead of one bar per key, every column on the page got its own bar bearing all the characters. The bars shift vertically until the wanted character sits on the print line, then a row of hammers fires at once. IBM's 402, 403 and 407 accounting machines printed this way, the last of them at roughly 150 lines a minute.
The problem is inertia. Every bar has to accelerate, stop and reverse for each line, and the mechanism wears at the same rate. Chain and drum printers sidestepped it by keeping the type moving continuously in one direction and timing the hammer strike instead — the IBM 1403 hit 600 lines a minute in 1959 on the same paper width. Typebars vanished from machine rooms within a decade, but stayed in typewriters well into the 1960s until the typeball displaced them.