Stupid Photocopier Question


Senior member
Dec 25, 2001
Hi, I'm in the market for a photocopier, and I have a question about an argument me and my friend were having. He says that in order for a copier to do duplex printing, it has to have one of those automatic document feeders where you stick in a stack of sheets, and it automatically copies all of them. I was saying that I could've sworn I've seen copiers where you stick it onto the flatbed, and it does two-sided copying somehow. He says no, it's not possible, because the feeder has to take the sheets and flip them over and copy both sides. Is he right? Please tell me he is wrong :D


Diamond Member
Feb 18, 2001
You're actually both right. Both things exist and sometimes they exist as the same device.

You can put a sheet directly on some flatbeds and it can then flip it over using it's document feeder which sits immediately above the flat bed.


Golden Member
Mar 6, 2004
All "duplex printing" means is double-sided printing (I assume you know that already).

A photocopier does not have to have a document feeder (typically referred to as an "ADF," or automatic document feeder), although most machines that duplex do have an ADF. There are several ways to make a copier do duplexing:

1) The easiest, and the most common (but also the most expensive) is to get a machine with both an ADF and a duplexer. The duplexer (or "duplex unit") sits directly underneath the copier and actually looks like it's part of it. When you select 2-sided copying on the keypad, the machine feeds the document from the ADF onto the glass, copies the first side, and the machine sends that copied page down into the duplexer. The ADF then flips the original over, the machine copies it, and the duplexer feeds the copied page back thru the copier (on its other side) to imprint that second image onto the second side of the paper. Then both the original and the copied page are exited from the machine. This is the way to go if you do more than a minimal amount of duplexing.

2) You can also buy a copier without a duplexer or an ADF and still do duplexing -- you just have to do it manually. Set the original on the glass, make a copy, take that copy and then put it in the "sheet bypass" or "manual feed" tray (and you want to flip it over and turn it upside down). Then lift the lid, turn your original over to copy its second side, and hit the PRINT button (or COPY button or whatever). The machine will detect that you put a piece of paper in the bypass tray and automatically know to draw paper from there (as opposed to pulling from one of the paper cassettes). So the page you printed first is now going thru the machine a second time -- on its other side -- and you're copying the original's second side onto it. Voila -- you again have a 2-sided copy. This is the way to go if you can't afford a machine with an ADF and a duplexer or if you only do occasional 2-sided copying.

3) You can also get a machine with just a duplexer and no ADF and do duplexing. It's not quite as convenient as Option 1 above, but it's a bit easier than Option 2 above. You could also do it with an ADF and without a duplexer, but if I try to explain every possible configuration, you'll go nuts trying to understand it all! :)

You do NOT have to have a document feeder to do duplexing on a photocopier. You can flip the pages over yourself simply by lifting the lid and turning them over. It's just easier with an ADF.

Hope this helps you win your argument (you are right, your friend is mistaken). (In case you care, I was a senior copier/fax tech for about 7 years in my previous career.)