An automatic document feeder is a device that feeds multiple sheets of paper into the bed of a copier, scanner or fax machine for automatic rather than manual operation. The capacity of the feeder can vary, and it can handle duplication of both sides of each document, not just one side. Many manufacturers of scanners, copiers, all-in-one devices, fax machines and so forth build an automatic document feeder into their design or sell an attachment for users who want to add one later.
Without a document feeder, the operator needs to manually feed each sheet of paper in or lay it out on the platen used as the bed of a copier or scanner. This can be time-consuming, and it can generate errors. A fax machine, for example, might terminate a connection if the user is too slow and fails to feed the next page in time. Especially if the operator needs copies of both sides, not just one, manual document feeding can be time-consuming and error-prone.
The automatic document feeder allows an operator to insert a stack of papers, program the machine and walk away while it copies, scans or transmits the information on the documents. Some machines use a reversing technology to pull data from one side and then the other, and others operate in duplexing mode to scan both sides. The automatic document feeder has guides to keep the paper in place while the machine processes the job, and these can be adjusted to accommodate different paper sizes.
Installation of an automatic document feeder does add bulk and can make the top or opening much heavier than other models. It is important for a user to be careful with a document feeder that is mounted to a swing-up top such as the kind used on many copiers and scanners. If the operator does not handle the top carefully, the document feeder might slam into the table or wall, and it might not work properly if the impact breaks something inside.
Errors can occur with an automatic document feeder. Very thin paper sheets might stick together, and thick paper might be too bulky for the device to handle. Textured paper or paper that has deckled edges can also jam. At best, this might cause a problem with the job, but it also could ruin the original. If paper is fragile, oddly sized, very thick or very thin, it might be a better idea for it to be fed through manually.