Machine for writing characters similar to those made by printers' types, especially a machine in which the characters are produced by steel types striking the paper through an inked ribbon, the types being activated by corresponding keys on a keyboard and the paper being held by a roller (the platen) that is automatically moved along with a carriage when a key is struck. The first practical typewriter was patented in 1868 by Christopher L. Sholes; commercial production began at the Remington firearms company in 1874. By the end of the century the typewriter had come to dominate the American office. The first electric typewriter for office use was introduced in 1920. From the 1970s typewriters began to be replaced by personal computers and their associated printers.