Duplex printing machine

摘要

In a perfecting printing machine, a switch-back mechanism moves backwardly each sheet delivered out of the printing section, and a switching gate provided immediately after the switch-back mechanism selects a first sheet path to return the sheet whose one side has been printed to the printing section and a second sheet path so that the sheet whose both sides have been printed is delivered to the stacker after being moved backwardly by the switch-back mechanism.