The Typewriter reference article from the English Wikipedia on 24-Jul-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Typewriter

Connect with a children's charity on your social network

Image:Typist.JPG
A typist typing on a typewriter.
1st decade of 20th century

A typewriter is a mechanical, electromechanical, or electronic device with a set of "keys" that, when pressed, cause characters to be printed on a document, usually paper.

In the late 19th and the start of the 20th century a person who operated such a device was sometimes also called a "typewriter", but it then became more common to call the person a "typist".

A typewriter has a keyboard, with keys for the characters in its font. The method by which the typewriter actually marks the paper now varies as greatly as types of printerss do, but until the end of the 20th century was by the impact of a metal (or, later, metallized plastic) type element against an "inked" ribbon which caused ink to be deposited on the paper. Carbon paper was sometimes inserted between multiple pieces of paper, so the impact also caused duplicate characters to be printed on each layer of paper.

Table of contents
1 Innovations
2 Electric designs
3 Non-impact technologies
4 Typewriter legacy
5 Correction methods
6 Related topics
7 External links

Innovations

No one person can be said to have invented the typewriter. Like the light bulb, automobile, telephone and the telegraph, a number of people contributed insights and inventions which eventually resulted in commercially successful instruments. In 1714 Henry Mill obtained a patent in Britain for a machine that from the patent sounds similar to a typewriter, but nothing further is known. [1]. Other early developers of writing machines include Pellegrino Turri (1808) who also invented carbon paper. Many of these earliest machines, including Turri's, were developed to allow the blind to write.

an index typewriter with a circular keyboardEnlarge

an index typewriter with a circular keyboard

In 1829 William Austin Burt patented a machine called the "Typographer." Like many of these other early machines, it is sometimes listed as the "first typewriter;" the South Kensington Science Museum describes it merely as "the first writing mechanism whose invention was documented," but even that claim may be excessive since Turri's machine is well known. Even in the hands of its inventor it was slower than handwriting. Burt and his promoter John D. Sheldon never found a buyer for the patent, and it was never commercially produced. Because it used a dial to select the character instead of having an individual key for each character, it was an "index typewriter" rather than a "keyboard typewriter", if it is to be considered a typewriter at all. From 1829 to 1870, many printing or typing machines were patented by inventors in Europe and America, but none went into commercial production. See Charles Thurber's 1845 Chirographer as an example.

A true typewriter was invented in 1864 by Peter Mitterhofer but was never produced commercially. In 1865 Rev. Malling Hansen of Denmark produced the Hansen Writing Ball (schreibkugel) which went into commercial production in 1870 and was the first commercially sold typewriter. It was a success in Europe and was reported being used in offices in London as late as 1909. Additionally, Hansen used a solenoid escapement to return the carriage on some of his models, and was responsible for the first "electric" typewriter.

In 1867 Christopher Sholes, Carlos Glidden, and Samuel W. Soule invented another typewriter. The Sholes and Glidden typewriter was the first device that allowed an operator to type substantially faster than a person could write by hand. The patent (US 79,265) was sold for $12,000 to a couple of entrepreneurs who made an agreement with E. Remington and Sons (then famous as a manufacturer of sewing machines), to commercialize what was known as the Sholes and Glidden Type-Writer. Remington started production of their first typewriter on March 1, 1873 in Ilion, New York.

The ability to view what is typed as it is typed is taken for granted today. In all early keyboard typewriters, however, the typebars struck upwards against the bottom of the platen. Thus, what was typed was not visible until the typing of subsequent lines caused it to scroll into view. The difficulty with any other arrangement was ensuring that the typebars fell back into place reliably when the key was released. This was eventually achieved with ingenious mechanical designs, and so-called "visible typewriters" were introduced in 1895. Surprisingly, the older style continued in production as late as 1915.

Image:typewriter.jpg

Mechanical typewriter with carriage return

In the original design style, now known as a "mechanical" or "manual" typewriter, each key was attached to a typebar that had the corresponding letter molded into its other end. When a key was struck briskly and firmly, the typebar hit a ribbon (usually made of inked fabric) stretched in front of a cylindrical platen that moved back and forth. The paper was rolled around by the typewriter's platen which was then rotated by a lever (the "carriage return" lever at the far left) to each new line of text. Some typewriters used ribbons that were inked in black and red, each a stripe half the width and the entire length of the ribbon. A lever allowed switching between colors for typing bookkeeping entries, where negative amounts had to be in red.

Electric designs

Electrical typewriter designs removed the direct mechanical connection between the keys and the element that struck the paper. Nevertheless, up to the 1980s, electric typewriters could be better described as "power-assisted typewriters." They contained only a single electrical component in them, the motor. Where the keystroke had previously moved a typebar directly, now it engaged mechanical linkages that directed mechanical power from the motor into the typebar. This was also true of the forthcoming IBM Selectric.

IBM and Remington electric typewriters were the leading models until IBM introduced the IBM Selectric typewriter, which replaced the typebars with a spherical typeball (more correctly, "element"), slightly smaller than a golf ball, with the letters molded on its surface. The Selectric used a system of latches, metal tapes, and pullies driven by an electric motor to rotate the ball into the correct position and then strike it against the ribbon and platen. The typeball moved laterally in front of the paper instead of the former platen-carrying carriage moving the paper across a stationary print position.

Image:typeball.JPG
Typeball
spherical element

The typeball design had many advantages, especially in eliminating of "jams" when more than one key was struck at once, and in the ability to change the typeball, allowing multiple fonts to be used in a single document. Selectric mechanisms were widely incorporated into computer terminals in the 1970s, because the typing mechanism was fast and jam-free; could be initiated by a short, low-force mechanical action; and did not require the movement of a heavy "type basket" in order to shift between lower- and upper-case.

Image:daisy_wheel.JPG
Daisy Wheel
letters disk

Later models of Selectrics replaced inked fabric ribbons with "carbon film" ribbons that had a dry black or colored powder on a "once-thru" clear plastic tape. These could be used only once but they were in a cartridge that was simple to replace. They also introduced auto-correction, where a sticky tape in front of the print ribbon could remove the black-powdered image of a typed character, and introduced selectable "pitch" so that the typewriter could be switched among pica ("10 pitch"), elite ("12 pitch"), and sometimes agate ("15 pitch"), even in one document. Even so, all Selectrics were monospaced -- each and every character was the same width. Although IBM had produced a successful typebar-based machine, the IBM Executive, with proportional spacing, no proportionally-spaced Selectric office typewriter was ever introduced. There was, however, a much more expensive proportionally-spaced machine called the Selectric Composer which was considered a typesetting machine rather than a typewriter.

The final major development of the typewriter was the "electronic" typewriter. Most of these replaced the typeball with a daisy wheel mechanism (a disk with the letters molded on the outside edge of the "petals"). A plastic daisy-wheel was much simpler and cheaper than the typeball but wore out more easily. Some electronic typewriters were in essence dedicated word processors with internal memory and cartridge or diskette external memory-storage devices. Unlike the Selectrics and earlier models, these really were "electronic" and relied on integrated circuits and multiple electromechanical components.

Non-impact technologies

Towards the end of the commercial popularity of typewriters in the 1980s, a number of hybrid designs combining features of computer printers and typewriters were introduced .

These typically incorporated keyboards from existing models of typewriters and the printing mechanism of dot-matrix printers. The generation of teletypes with impact pin-based printing engines was not adequate for the demanding quality required for typed output. Newly developed, thermal transfer technologies used in thermal label printers had become technically feasible for typewriters.

IBM produced a series of typewriters called Thermotronic with letter-quality output and correcting tape along with printers tagged Quietwriter. Brother extended the life of their typewriter product line with similar products.

The development of these proprietary printing engines provided the vendors with exclusive markets in consumable ribbons and the possibility to use standardised printing engines with varying degrees of eletronic and software sophistication to develop product lines.

The increasing dominance of personal computers and the introduction of low-cost, truly high-quality, laser and inkjet printer technologies eventually displaced dedicated typewriters.

Typewriter legacy

In the developed world, with the proliferation of the personal computer, typewriters have faded into near-obscurity and are now used mainly by people without access to, or the training to use, a computer, and for specialized applications such as filling out forms. The monospaced, stark, and slightly uneven look of typewritten text can have some artistic appeal, and some people, young or old, prefer to use a typewriter occasionally.

Image:UnderwoodKeyboard.jpg
QWERTY typewriter
de facto standard

In some countries where personal computers are not ubiquitous, one may go to the public square and find individuals who gather there with their old but sturdy typewriters. These individuals rent out their services as on-the-spot letter writers, accepting dictation from their customers, who may be illiterate or who simply do not own a typewriter.

Keyboard layout

The 1874 Sholes & Glidden typewriters established the QWERTY layout for the letter keys that is used in virtually all computer and other keyboards nowadays. This layout of keys has been adopted as the de facto standard for English-language keyboards. Other nations using the Latin alphabet use variants of the QWERTY layouts, for example the French AZERTY, Germans QWERTZ layout.

Radically different layouts such as the Dvorak keyboard have been proposed but have not been able to displace the QWERTY layout, despite the advantages claimed by their proponents.

Correction methods

According to the standards taught in secretarial schools in the mid-1900s, a business letter was supposed to have no mistakes and no visible corrections. Accuracy was, therefore, prized as much as speed. Indeed, typing speeds, as scored in proficiency tests and typewriting speed competitions, included a deduction of ten words for every mistake that was made.

Corrections, were, of course, necessary, and a variety of methods and technologies were used.

The traditional method involved the use of a special typewriter eraser. The typewriter eraser was made of fairly hard, stiff rubber, containing abrasive material. It was in the shape of a thin, flat disk, approx. 2 inches in diameter by 1/8 inch thick allowing for the erasure of individual typed letters. Business letters were typed on heavyweight, high-rag-content bond paper, not merely to give a luxurious appearance, but also to stand up to erasure. Typewriter erasers were equipped with a brush for brushing away eraser crumbs and paper dust, and using the brush properly was an important element of typewriting skill, because if erasure detritus fell into the typewriter, a very small buildup could cause the typebars to jam in their narrow supporting grooves.

Erasing a set of carbon copies was particularly difficult, and called for the use of a device called an eraser shield to prevent the pressure of erasure on the upper copies from producing carbon smudges on the lower copies.

Paper companies produced a special form of typewriter paper called erasable bond (for example, Eaton's Corrasible Bond). This incorporated a thin layer of material that prevented ink from penetrating and was relatively soft and easy to remove from the page. An ordinary soft pencil eraser could quickly produce perfect erasures on this kind of paper. However, the same characteristics that made the paper erasable made the characters subject to smudging due to ordinary friction, making it unacceptable for business correspondence or anything archival.

In the fifties and sixties, correction fluid made its appearance, under brand names such as Liquid Paper and Wite-Out. This was a kind of opaque white fast-drying paint which produced a fresh white surface onto which a correction could be re-typed. However, when held to the light, the covered-up characters were visible, as was the patch of dry correction fluid (which was never perfectly flat, and never a perfect match for the color, texture, and luster of the surrounding paper). The standard trick for solving this problem was Photocopying the corrected page, but this was possible only with high quality photocopiers, and was not practical with color letterheads.

Dry correction products under brand names such as Ko-Rec-Type were introduced in the seventies and functioned like white carbon paper. A strip of the product was placed over the letters needing correction, and the incorrect letters were retyped, causing the black character to be overstruck with a white overcoat. Similar material was soon incorporated in carbon-film electric typewriter ribbons; like the traditional two-color black-and-red inked ribbon common on manual typewriters, a black/white correcting ribbon became commonplace on electric typewriters.

The pinnacle of this kind of technology was the IBM Correcting Selectric. This machine, and similar products, incorporated a black/white ribbon and a character memory. With a single keystroke, the typewriter was capable of automatically reversing and overstriking the previous few characters with white cover-up.

Related topics

Office Printerss and Fonts Typewriter Museums Other
Keyboards Corporations and typewriters Encryption Use as Computer peripherals

External links