The Riken research institute (abreviation of Rikagaku Kenkyūjo, meaning Physico-Chemical Research Institute) and the Riken foundation exist since 1917. In 1927 was created the Rikagaku Kōgyō K.K., meaning Physico-Chemical Development Co., Ltd.) to market products derived from the research of the institute. On Feb. 6, 1936, the photographic paper division became Riken Kankōshi K.K., meaning Riken Sensitized Paper Co Ltd) and was placed under the responsibility of Ichimura Kiyoshi, who is thus considered as the founder of today's Ricoh. The factory was located in Ōji, Tokyo.

In 1937, Riken Kankōshi bought the company Asahi Bussan and its associated manufacturing facility, producer of the Olympic and Super Olympic cameras. This company had started the distribution of Olympic cameras in 1934 and released the Super Olympic in 1935 or 1936. In November, Riken reorganized these into the dependent company Asahi Kōgaku Kōgyō (unrelated to the other Asahi Kōgaku predecessor of Pentax), which would continue the production of bakelite cameras and leaf shutters in a semi-independent way.

In March 1938, Riken Kankōshi itself became Riken Kōgaku Kōgyō K.K., meaning Riken Optical Industries Co., Ltd.). The same year, it announced the Riken No.1, a 3×4cm camera with focal-plane shutter, which was actually released in 1939 as the Gokoku. The camera was produced in the Ōji plant, and was followed by the Ricohl, Roico, Ricohflex B, Gaica or Kinsi before the production was ended by the war.

The company finally took the name of its products, becoming Ricoh (K.K. Rikō, ㈱リコー) in 1963. From 1964, it made a few 35mm SLR with interchangeable 42mm screw lenses, most of which were called Singlex. In 1977, it switched to the K mount introduced by Pentax, for a series of cameras called XR, made until the 1990s. The only autofocus SLR cameras made by the company were the various Mirai, with non-interchangeable zoom lenses.

In 2011, Ricoh acquire PENTAX Imaging Systems Business.