Sheet stacking apparatus

Sheet stacking apparatus for a buffer tray of a reprographic machine comprises a belt feeder including, at the input end of the feeder, a baffle which imparts a curved configuration to sheets in a direction transverse to the direction of travel. The output end of the feeder is defined by an output roll which cooperates with the belt of the feeder and is movable with the adjustable end guide of the buffer tray so that, as the length of the tray is increased, the length of the sheet path through the feeder is decreased and vice versa. The curved sheet configuration is maintained as sheets are conveyed through the feeder by the belt and is then further maintained by a second baffle as sheets are fed out, by the output roll, over the buffer tray.