Sholes and Glidden typewriter length. The redesigned platen also introduced the modern spacing functionality (horizontal and axial movement providing letter and line spacing, respectively). The cylindrical platen became "an indispensable part of every standard [typewriter]". By the end of 1872, the appearance and function of the typewriter had assumed the form that would become standard in the industry and remain largely unchanged for the next century. Although the machine possessed a cylindrical platen and what was essentially a QWERTY keyboard, two design elements that would later become essential were lacking: the ability to write in upper and lowercase letters and "visible" print. Although the
Typewriter was acquired by IBM, which then spent on a redesign of the Electromatic Typewriter, launching the IBM Electric Typewriter Model 01 in 1935. By 1958 IBM was deriving 8% of its revenue from the sale of electric typewriters. In 1931, an electric typewriter was introduced by Varityper Corporation. It was called the "Varityper", because a narrow cylinder-like wheel could be replaced to change the font. Electrical typewriter designs removed the "direct" mechanical connection between the keys and the element that struck the paper. Not to be confused with later "electronic" typewriters, electric typewriters contained only a single electrical component: the