A single-feed scanner is a device that accepts only one document at a time. The operator must insert the next item manually once the scanner finishes with the previous one. In contrast, other scanners can be loaded with a stack of many items at once, which are then scanned automatically – these may be called multi-feed, automatic feed, or simply high-speed scanners.
Single-feed check scanners tend to be less expensive than their high-speed counterparts, and are therefore very popular in cases where only a few checks at a time need to be scanned. As the number of checks increases, such as at a bank teller window, repeatedly inserting items one at a time slows the process down enough that a multi-feed device may be called for.
There are different methods that a single-feed scanner can use to scan the document. Some will feed the item through and into an exit pocket, much like high-speed scanners. Others (as in the example at right) eject the document back through the input tray in a process known as feed-and-return. Still others will feed the item straight through and out the back or bottom, depending on the orientation of the device; this is called pass-through feeding.