An image duplicating apparatus having an automatic document feed device. The document feed device is movable between an opened and a closed position, and is operable to automatically convey documents to a document support table of an image forming device, and to automatically discharge documents from the document support table after images from the documents have been copied by the image forming device. An automatic document discharge prohibit instruction is produced by a control arrangement of the apparatus when a document is manually placed on the document support table, however a document discharge instruction may be manually entered to override the prohibit instruction, if desired by an operator of the apparatus.