Electrophotographic copying apparatus with variable magnification

In an electrophotographic copying apparatus with variable magnification which includes a photosensitive member driven at a predetermined speed so as to sequentially pass an exposure station, a developing station and an image transfer station, a scanning means for scanning an original document at a speed corresponding to a copying magnification, a projecting means for projecting light image of the original document scanned by said scanning means onto the exposure station of the photosensitive member so as to form an electrostatic latent image corresponding to the original document on said photosensitive member, a developing means for developing said electrostatic latent image into a toner image, means for transporting a copy material towards the image transfer station from a predetermined stand-by position, and means for transferring the toner image on the photosensitive member onto the copy material fed by said transporting means at the image transfer station, the improvement comprising a first detecting means for detecting that said scanning means has reached an exposure starting position for substantially starting exposure and scanning of the original document, a second detecting means for detecting that said scanning means has reached a particular position spaced a predetermined distance from said exposure starting position, said predetermined distance being equal to a difference between a circumferential length of said photosensitive member from said exposure station to said image transfer station and a length of a transportation path from the stand-by position to the image transfer station, a reference pulse generating means, and a microcomputer including a counter unit which starts counting upon detection of said scanning means by said first detecting means, a memory unit for memorizing the count value of said counter unit upon detection of said scanning means by said second detecting means at least at a particular 1.times. magnification mode, and a control unit for actuating said transporting means upon coincidence of the count value of said counter unit with the memorized value of said memory unit during the scanning by said scanning means in a copying mode at magnification other than the 1.times. magnification, whereby a leading edge of the copy material being transported is registered with a leading edge of said toner image on said photosensitive member at said image transfer station irrespective of copying magnifications.