Typewriter

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.

Forensic identification

Because of the tolerances of the mechanical parts, slight variation in the alignment of the letters and their uneven wear, each typewriter has its individual "signature" or "fingerprint", allowing a typewritten document to be tracked back to the typewriter it was produced on. In the Eastern Bloc, typewriters (together with printing presses, copy machines, and later computer printers) were a controlled technology, with secret police in charge of maintaining files of the typewriters and their owners. (In the Soviet Union, the organization in charge of typewriters was the First Department of the KGB.) This posed a significant risk for dissidents and samizdat authors. This method of identification was also used in the trial of Alger Hiss.

Related Topics:
Fingerprint - Tracked back - Eastern Bloc - Printing press - Copy machine - Computer printer - Secret police - Soviet Union - First Department - KGB - Dissident - Samizdat - Alger Hiss

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Black/white computer printers have their "fingerprints" as well, but to less degree. Modern color printers and photocopiers typically add a steganographic pattern of minuscule yellow dots to the printout encoding the printer's serial number.

Related Topics:
Computer printer - Steganographic - Serial number

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Other forensic identification method can involve analysis of the ribbon ink.

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