Abstract: An image forming apparatus which facilitates the input and output of copy paper. One embodiment includes an image forming apparatus with paper supply trays, a development area, a console and a sorter. By pressing a transparent paper mode key on the console, normal and projector paper are sequentially fed from the trays to the development area and then to the sorter. The sorter is set in one of three modes by a sorter instructor. A manual key on the console allows an operator to set the instructor to position the sorter in any one of the three modes. The pressing of the transparent paper mode key or the detection by a detector of transparent paper in the feeding tray results in the instructor setting the sorter in a non-sort mode despite the sort instructor having been previously set in a different mode.