Mechanical devices used to type text onto paper, typewriters paved the way for modern word processors.
Mechanical typewriters work by imprinting inked key heads – containing one or more letters, numbers or symbols – onto a sheet of paper one after the other to form lines of text. To achieve this, five vital standardized parts are implemented into each typewriter’s body.
At the bottom-centre of the unit a mechanical keyboard is connected to a basket of typebars.
Qwerty keyboard layouts are common, although other layouts have also been used. When their corresponding key is be raised, guided by a segment channel vertically up to the unit’s ribbon.
The ribbon is a strip of fabric that was covered with the type’s ink. When struck by the head of the typebar – onto which letters, numbers and symbols have been affixed – the corresponding letter is then printed onto the sheet of paper.
The typewriter’s paper is held in place around a cylindrical tube referred to as a platen, which itself can move from left to right horizontally within a carriage system. The platen can be incrementally wound at the end of each line of text with the carriage return. The carriage return is a lever positioned at the end of the carriage, which drops the paper onto the next line for continued text.
Finally, the basket of typebars can be shifted up and down with the shift key, allowing its user to move between lower case and upper case type. Raising the typebar up to the ribbon in a new position means a different part of the typebar’s head can now strike the ribbon, imprinting a different letter, number or symbol.