a sheet feed machine comprising guides for holding sheets in a stack at a sheet input station , a first conveyor for successively feeding sheets from the bottom of the stack at the sheet input station into a stream with adjacent sheets in an overlapped configuration , and an inverter for inverting the stream of sheets at a sheet inversion station . a stop is located at a sheet output station for stopping the stream and accumulating sheets in a stack , and a second conveyor is provided for conveying the stream of sheets from the inversion station to the sheet output station .