The disclosure describes a variable magnification optical mechanism in an image forming apparatus in which a varied image at a selected magnification of an original image is formed. A photosensitive body on which the varied image is exposed is moved at a definite speed (v) irrespective of the selected...http://www.google.fr/patents/US4080062?utm_source=gb-gplus-shareBrevet US4080062 - Variable magnification optical mechanism
