Abstract: A duplexing apparatus for printing data or information on both sides of a sheet of paper to be used with laser printers or paper copiers is disclosed. Sheets of paper are fed from a paper feeding station for presentation to an image transfer station. The image transfer station transfers toned images, present on a photosensitive member, to the sheet of paper. After the transfer, the paper is moved along a discharge path to a duplex device which is disposed in close proximity to the paper feeding station. The duplex device engages the sheet of paper leaving the transfer station and either discharges the paper if printing is done thereon to a discharge station or returns the sheet of paper to the paper feeding station for a second presentation to the transfer station for duplex printing. Coded pagination information is sensed and sent to a microcontroller which checks the data to confirm that the pages of data on each of the sheets are being printed in the proper order.