Apparatus for inverting substrates

A copier capable of producing simplex and duplex copies includes a tri-roll inverter that employs a spring loaded ball on roll return force applicator located downstream from the tri-roll input/output members. The input nip of the inverter includes the combination of a smooth roll and a foam roll. This combination corrugates lightweight papers for penetrating the ball on roll nip. A sheet driven by the input nip into the inverter penetrates the ball on roll return force applicator nip. When the last portion of the sheet leaves the input nip, the friction return force of the applicator nip will cause the sheet to buckle into an output nip formed by the foam rolls of the tri-roll members for outward movement.