An accumulator for an automatic sheet media punching and collating system includes a proximal end, having a shoulder, a distal end, and a moveable collating belt, disposed below the shoulder, extending from the proximal end to the distal end. The collating belt has an upwardly extending lower stop with an accumulating position opposite the shoulder, defining a drop region. The lower stop is configured to contact a lower edge of sheets of media sequentially received at the proximal end, whereby the sheets stop and accumulate in the drop region in a lift in a book order. The collating belt is selectively moveable to discharge the lift as a unit toward the distal end.