What is "risograph"

n. A high-speed printing machine used for high-volume photocopying by means of an internal stencil.

Risograph is a high-speed digital printing system manufactured by the Riso Kagaku Corporation and was designed mainly for high-volume photocopying and printing. It was released in Japan in August 1986. It is sometimes called a digital duplicator or printer-duplicator, as newer models can be used as a network printer as well as a stand-alone duplicator. When printing or copying many duplicates (generally more than 20) of the same content, it is typically far less expensive per page than a conventional photocopier, laser printer, or inkjet printer. Printing historian Rick O'Connor has debated that the original, and thus correct, name for the device is RISSO and not RISO. This debate spawns from the notion that an extra 'S' is added because the inventor's wife found it more pleasing to the ears.