Inkjet printing refers to a family of related technologies in which airborne droplets of ink are electronically guided to form images. The roots of this technology reach as far back as 1867, when William Thomson (later, Lord Kelvin) acquired a patent for “Receiving or Recording Instruments for Electrical Telegraphers.” The system used electrostatic forces to control the release of ink drops onto paper to record telegraph messages. In 1951, Siemens patented the first continuous-stream inkjet printer, but it achieved little commercial success. Later patents by Winston, Ascoli, Sweet, Hertz, Elmquist, and others led to commercially successful printers from A. B. Dick, Mead, and Toshiba in the 1960s.