dual bin laser printers can all potentially be used for single-sided
(simplex) and double-sided (duplex) printing. Installation
of a duplexer unit turns a simplex printer into a duplex one.
They print about 17 pages per minute (ppm) simplex and 15
ppm duplex, and come with resolutions of 300 dpi or 600 dpi.
Models include the HP LaserJet IIISi and 4Si, and The Printerworks'