Fitzpatrick, Cella, Harper & Scinto
Image forming apparatus with detecting and controlling means
 In an image forming apparatus wherein a plurality of developing devices are carried on a rotating body and the rotating body is rotated to thereby move desired one of the developing devices to a predetermined developing position and develop a latent image formed on a latent image bearing member in accordance with image information, an image forming operation is permitted only when all of the developing devices are carried on the rotating body. 
Canon Kabushiki Kaisha
G
G03G
inventional
Kimiyoshi Yasushi Akio Kazuhiko
Hayashi Murayama Ohno Hirooka