what is adf printer

An ADF (Automatic Document Feeder) is a feature found in multifunction printers, scanners, and copiers that allows the user to feed several pages into the machine, one page at a time, without having to manually replace each page. This feature enables the user to scan, copy, print, or fax multiple-page documents without having to manually insert each piece of paper. ADFs are rated by speed, in pages per minute (ppm), and capacity, usually in a range from 10 sheets to 200. There are two kinds of document feeders capable of two-sided (duplex) scanning: a reversing automatic document feeder (RADF) scans one side of a page, then flips it and scans the other side, while a duplexing automatic document feeder (DADF) scans both sides in one pass. The advantage of the DADF is faster speed for two-sided originals. ADFs are standard features for most printers, fax machines, and large photocopiers.