A method of feeding paper through a printer. Tractor-feed printers have two sprocketed wheels on either side of the printer that fit into holes in the paper. As the wheels revolve, the paper is pulled through the printer. Tractor feed is also called pin feed.
The other principal form of feeding paper into a printer is friction feed, which utilizes plastic or rubber rollers to squeeze a sheet of paper and pull it through the printer.
Tractor-feed printers require special paper (with holes), whereas friction feed printers can handle most types of cut-sheet paper, including envelopes. Some printers support both types of feeding mechanisms.