Duplex printing means printing on both sides of a sheet of paper. Automatic duplex printers flip each page internally and print both sides on their own, while manual duplex has you turn the stack over and feed it again. It saves paper and creates booklet-style documents, and you turn it on in the print settings.
Why this happens
Duplex is simply a printing feature, not a fault. The word duplex means two-sided, the opposite of simplex, which is single-sided printing on one face of each sheet.
There are two kinds:
- Automatic duplex: the printer has a built-in mechanism that pulls the page back in, flips it, and prints the second side with no help from you.
- Manual duplex: the printer prints all the odd pages, then prompts you to reload the stack the other way so it can print the even pages on the backs.
Whether your printer supports automatic duplex depends on the model. If it does not, you can still do manual duplex through the print dialog or by reprinting selected pages.
Is this normal?
Yes. Duplex printing is a standard, widely used feature, common in offices and schools to save paper. Many printers turn it on by default for that reason.
Does it cause any problems?
Duplex printing is slightly slower because the printer pauses to flip or wait for each sheet, and very thin paper can show ink from the other side. Otherwise it works well and causes no harm.
How to fix or check it
- To turn duplex on in Windows, open the print dialog, click Preferences or Printer Properties, and look for Print on Both Sides or Two-Sided, then choose to flip on the long edge or short edge.
- To turn duplex on in Mac, open the print dialog, and in the layout options select Two-Sided, then long-edge or short-edge binding.
- Choose long-edge binding for normal book-style documents and short-edge binding for pages that flip like a notepad.
- If you do not see a two-sided option, your printer may not support automatic duplex. Select manual duplex if offered, and follow the prompt to reload the paper.
- To do manual duplex yourself, print the odd pages first, flip the stack the correct way, then print the even pages.
- To always print single-sided, set the default to One-Sided in the printer preferences on your computer.
Frequently asked questions
What is the difference between duplex and simplex printing?
Simplex prints on one side of each sheet only. Duplex prints on both sides. Duplex uses about half the paper for the same document, which is why it is popular for longer files.
What do long edge and short edge mean in duplex settings?
They set which way the back page is oriented. Long-edge binding flips pages like a book, keeping text upright on both sides. Short-edge binding flips like a calendar or notepad, useful for landscape documents.
Can any printer do double-sided printing?
Any printer can do manual duplex, where you reload the paper yourself. Only printers with a built-in duplex unit can flip and print both sides automatically. Check your printer's specifications to see which you have.