A sheet finishing apparatus for an image forming apparatus includes a discharging member configured to discharge recording media. A tray is configured to receive the discharged recording media. A rotatable moving member is configured to contact the discharged recording media such that an angular position of the rotatable member changes in response to a number of the recording media on the tray. A detecting member is configured to detect a movement of the moving member. A controller is configured to control an output of the recording media to the tray based on an output of the detecting member.