Automatic document feeder

What does it do?

An automatic document feeder (ADF) is a mechanism mounted on the top of scanners and printers – such as the Epson Ecotank ET4800 (pictured) – that automatically feeds sheets of paper through the device. It makes scanning and printing multi-page documents faster and easier.

How does it work?

Documents are placed into the ADF’S paper tray. The sheets are then mechanically extracted, one at a time, and run through the scanner/printer. It’s similar to the way a printer collects the next sheet of blank paper to be printed.

The ADF may use the entire scanning bed, or have a separate smaller scanning area. The latter option uses the passage of the paper through the ADF to scan the entire sheet, rather than moving the scanning mechanism across the whole page like a standard flatbed scanner. Once scanned, pages are usually ejected to a separate out-tray below the main document storage area.

What are the specs?

The differentiating factor between most ADFS is how many sheets they can hold. This is usually 25 to 35 sheets on a multifunction printer aimed at home offices, though business machines may be capable of holding considerably more.

Most ADFS only scan one side of a sheet, so you have to ensure the document is placed the correct way up. A few models let you scan both sides of a sheet, but this duplex function tends to be limited to more expensive copiers designed for business use.

Can I change it later?

No, an ADF is a built-in function and can’t be changed at a later date.