If you're in the market for a copier or if you're trying to master the features of one you've newly purchased, you'll have noticed that copiers have a whole vocabulary of their own. For example, in this specialized world, the term "duplex" doesn't refer to a house. Instead, copiers -- or printers -- are said to be capable of duplexing if they can provide double-sided output.
Single-sided copying is a simple one-button affair. When you want both sides of a sheet copied or two separate originals turned into one multi-sided copy, that's where duplexing comes in. Most machines have push-button or touch-screen options to select duplex output and to choose either a two-sided original or two single-sided originals. Consult the manual for directions specific to your own model, or -- if you're still shopping -- ask the sales rep to demonstrate the feature.
High-end business-class copiers have the ability to manage complex paper paths, so they're easy to use for duplexing. Insert your single-sided or two-sided originals as prompted, and the machine makes two printing passes to create your dual-sided outputs. Small, home-oriented machines are often duplex-capable but require you to turn the paper manually after the first side prints. Lift the one-sided prints from the output tray and tap them on your desk to ensure they're neatly lined up. Place them back in the copier's in tray and press the button to restart the copying.