Duplicating system comprising electrophotographic copying apparatus and option device

摘要

A duplicating system comprises an electrophotographic copier which includes a first optical scanning system for making a slit exposure, a first document feeder for feeding a first document to be copied at a first speed with respect to the first optical scanning system, a rotating photosensitive drum for forming an electrostatic latent image corresponding to the image of document, apparatus for forming a duplicated copy with the aid of the latent image and a sequence control circuit for controlling a duplicating operation in such a manner that the image of first document is projected onto the photosensitive drum from an imaginary control start position. An option device is detachably mounted on the copier and comprising a second optical scanning system for making a slit exposure, a second document feeder for feeding a second document to be copied at a second speed with respect to the second optical scanning system and an optional optical system for projecting the image of second document onto the photosensitive drum. The second document feeder and second optical scanning system in the option device have a geometrical configuration similar to that of the first document feeder and first optical scanning system in the copier so that the image of second document is projected on the photosensitive drum from the same position as the imaginary control start position, so that the duplicating operation for the second document with the option device is commonly controlled by the sequence control circuit provided in the copier.