JPH0552489B

PURPOSE:To execute the unloading or gathering work of copying paper smoothly by comparing the size of originals set up on plural document trays, feeding these documents in the descending order of size and discharging the copying paper in the ascending order of size when executing ADF copying with plural documents trays. CONSTITUTION:Document detecting parts 10-17 for detecting documents set up on the document tray are constituted of opposite transmission type photoelectric switches. When a document is set up, the bent part of an actuator 19 is depressed by the weight of the document and a free end part 21 is unloaded from a groove part, so that light projection from a projector 22 is not interrupted. The photodetecting output of a photodetector 23 is changed in accordance with the rocking motion of the actuator 19 and the existence of the document on the document tray can be detected by the change. Then, the size of the set document can be decided on the basis of the set position of the document detecting part detecting the existence of the document. The sizes of the document set up on an upper document tray 3 and a lower document tray 4 are detected and compared and the document having larger size is fed in priority to execute the copy of the document.