The typewriter—a writing machine invented to make the process of writing faster.
The typewriter is a machine that produces printed letters and figures on paper. People in homes and offices throughout the world use typewriters to write rapidly and neatly. The typewriter ranks as the most widely used kind of business machine.
Kinds of Typewriters
There are four basic kinds of typewriters: (1) manual, (2) electric, (3) electronic, and (4) text-editing, usually called word-processing typewriters or word processors.
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A manual typewriter operates entirely by the power sup-1 plied by the typist’s hands. An electric typewriter has an electric motor top provide power, and so the typist only needs to touch the keys lightly. Such – a typewriter costs more to buy and operate than a manual typewriter, but it is easier to use. It also enables a person to type faster and more neatly.
Some electric typewriters, called self-correcting writers, erase typing | errors. Chemically treated correcting ribbons cause any incorrect figure to I peel off when the typist presses a certain key. The typist then types the correct character in the space left blank.
Manufacturers make portable models of manual, electric, and electronics typewriters. The greater compactness and lighter weight of portable typewriters make them popular among students and travellers.
Electronic typewriters resemble electric typewriters but include a tiny computer called a microprocessor. The microprocessor enables the typewriter to automatically perform such functions as setting margins and underlining.
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Most microprocessors in electronic typewriters also have a memory, which can store names, dates, addresses, and other material that a typist frequently repeats. When the typist presses the appropriate key, the machine ‘recalls’ the stored material and types it automatically. On some electronic typewriters, a display screen shows material as it is typed.
With word processors, the material the operator types are stored on a magnetic card, tape, or disk. The typist can make corrections by simply typing over an error. The typist can also add, delete, or move individual letters, words, lines, and paragraphs without retyping the entire document. After a document is typed and stored, the machine prints it out at the touch of a button. Some units print as many as eight pages per minute.
Most word processors have an electronic display screen. A microprocessor enables the machine to handle a variety of tasks. For example, most word processors can sort and merge lists, perform mathematical equations, and transfer information to other word processors and to computers over telephone lines.
Parts of a Typewriter
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Most manual, electric, and electronic typewriters have similar basic features. The machine has a keyboard that consists of buttons called keys. Each key carries two characters—letters, numbers, punctuation marks, or other symbols. A key forms one end of a lever that has a bar of metal type at the other end. When the typist strikes a key, the type bar rises and hits an inked ribbon or a thin strip of carbon tape.
The ribbon or tape is in front of the paper, on which the type bar prints a letter or other character. A hard rubber roll called a platen holds the paper in the typewriter. The platen and paper automatically move one space to the left after the typist strikes a key.
Some typewriters do not have type bars. Instead, they have a ball-shaped font or typing element, which contains a complete set of all the characters. When the typist strikes a key, the ball turns so that the correct character hits the paper. The ball moves along the line being typed, but the platen does not move. The type style or size can easily be changed by replacing the ball. Many electronic typewriters have a printing element called a daisy wheel. When the typist strikes a key, the daisy wheel spins until the correct character is in place.
A warning bell rings when the typist nears the end of a line. A lock prevents any typing past a particular point unless the typist presses the margin-release key. Most typewriters also have an automatic ribbon reverse, a backspace lever, and a tabulator, which enables the machine to line up numbers or words in columns.
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Typewriter manufacturers produce more than 5,000 kinds of keyboard and over 100 type styles. Some keyboards have the letters and symbols of various languages. Others feature special symbols, such as those used music. Some typewriters have large type for the partially sighted. Some typewriters for the blind are equipped with special devices that “speak” characters as they are typed. Others type in Braille.
On many typewriters, each letter or other character fills the same amount of space on the paper. But some typewriters feature proportional spacing, in which the space taken by each character varies according to its size. Proportional spacing gives letters the appearance of having been printed. Some machines have a justifier, a device that provides right hand margins that are even.