Noiseless typewriters The noiseless linkage is a variation of the conventional typebar linkage causing the typebar to strike the platen at a lower velocity but with the same momentum. Although it produces less noise than the conventional typewriter, the noiseless typewriter cannot produce as fine an impression or as many carbon copies.

Electric typewriters A significant advance in the typewriter field was the development of the electric typewriter, basically a mechanical typewriter with the typing stroke powered by an electric-motor drive. The typist initiates the key stroke, the carriage motion, and other controls by touching the proper key. The actuation is performed by the proper linkage clutching to a constantly rotating drive shaft. Advantages of this system include lighter touch, faster and more uniform typing, more legible and numerous carbon copies, and less operator fatigue. Especially valuable as an office machine capable of a high volume of output, electric typewriters are produced by all major typewriter manufacturers. The first electrically operated typewriter, consisting of a printing wheel, was invented by Thomas A. Edison in 1872 and later developed into the ticker-tape printer. The electric typewriter as an office writing machine was pioneered by James Smathers in 1920. In 1961 the first commercially successful typewriter based on a spherical type-carrier design was introduced by the International Business Machines Corporation. The sphere-shaped typing element moves across the paper, tilting and rotating as the desired character or symbol is selected. The motion of the element from left to right eliminates the need for a movable paper carriage.

Portable typewriters The early portables of the late 19th century were slow, awkward, type-wheel machines. In 1909 the first successful portables appeared on the market. By the 1950s practically every typewriter manufacturer produced a portable typewriter; all of them were typebar machines similar in operation to the office machines. Designed with lighter parts than those of standard models, portables are more compact but less sturdy. Electrical operation of portable typewriters was introduced in 1956.

Typewriter composing machines Special-purpose typewriting machines have been developed for use as composing machines; that is, to prepare originals that look as if they had been set in printer’s type (or at least more so than ordinary typewriting does), from which additional copies can be printed. Ordinary typewriting cannot compare in quality, style, and versatility with printing from type produced directly on metal slugs by standard composing machines, but the high cost of skilled typesetting labour prompted the development of composing typewriters that require far less operator training. Since the fundamental requirement of a composing typewriter is the ability to supply different styles and sizes of type, the type-wheel machine is far more suitable than the typebar. Other major requirements of a typing machine whose output must resemble print are the proportional spacing of characters in a word (rather than centring every character within the same width, as in ordinary typewriting) and justification, or alignment of the right-hand margin. An electric typebar machine was developed that provided proportional spacing—assigning space for each character in proportion to its width. The other requirement, margin justification, proved more difficult to attain. Most of these machines provided for preliminary typing of a line, determining the necessary compensation for the line length, and retyping to the exact length. A more complicated machine was introduced that would automatically justify a line of type with one keyboarding. This was accomplished by a system in which the operator typed manually into a storage unit, from which a computer first automatically compensated for line length and then operated a second typing mechanism. By mid-20th century the typewriter had begun to be used as a composing machine in spite of its limitations, and it became more popular as improvements were developed.

Automatically controlled machines One of the most important advances in the field of typewriters and office machines was the development of automatic controls that allow typing from remote electrical signals rather than from manual control. This technique enabled office machine manufacturers to develop an integrated system of business communication utilizing remote control typewriters and computer techniques. With such a system, machines handling all the different office machine functions, such as the typewriter, calculating machine, and printing telegraph, together with mass data processing computers and electronic storage systems, are tied together by the use of a “common language” in the form of coded electrical signals. This coded information, coming into an office via appropriate communication channels, can be automatically recorded and printed. Component machines produced by any manufacturer can be connected to any other without the use of special code converters. Other automatic typewriter devices also have become available. A vacuum-operated system, for example, controls and operates any number of standard typewriters from a perforated roll of paper tape, much like the player piano, making possible rapid production of form letters and other papers.

High-speed printers The need for high-speed printing machines to convert the output of computers to readable form prompted the introduction of a specialized high-speed form of “typewriter” in 1953. In this class of machines, the paper is fed between a continuously rotating type wheel and a bank of electrically actuated printing hammers. At the instant the proper character on the face of the type wheel is opposite the proper hammer, the hammer strikes the paper and prints the character, while the type wheel continues to rotate. By this means, speeds up to 100,000 characters per minute have been attained, as compared with about 1,000 characters per minute attainable with conventional typebar mechanisms. A number of different models operating on this principle were developed; all of them required elaborate electronic controls to solve the complex synchronization problem. Many other high-speed-output devices for computers were developed. Most of them utilize techniques that are remote from the typewriter field, in some cases using printing mediums other than paper. Speeds of up to 10,000 characters per second were attained by certain nonmechanical systems, which, although not actually typewriters, compete with typewriters as computer-output devices.

This article was most recently revised and updated by Robert Lewis , Assistant Editor.