Ricoh is a Japanese company established i 1936 as Riken Kankōshi (Riken Sensitized Paper). Its headquarters is located in Ricoh Building in Chūō, Tokyo.
Ricoh produces office equipment such as printers, photocopiers, and fax machines, as well as photographic equipment such as cameras. Ricoh has used a version of the Pentax K-mount (RK mount) for its line of SLR cameras since 1975. In 2011, Ricoh bought the Pentax camera business from Hoya.