A buffer apparatus configured to hold a stack of sheets includes an input, first and second side guides each having a face facing transverse to the travel direction, and a backstop facing the input and spaced from the input in the travel direction. The first side guide, second side guide and backstop define a hopper for holding a plurality of the sheets. First and second retractable supports are shiftable from first positions in which a first portion of the respective retractable support projects a first distance into the hopper and a second position in which the first portion of the respective retractable support projects a second distance into the hopper or does not project into the hopper, the second distance being less than the first distance. The at least one second retractable support is located between the input and the at least one first retractable support.