Patch Codes
Patch codes are a set of 6 distinct barcode patterns (1, 2, 3, 4, 6 and T) that are typically used as document separators when scanning.
Introduction
A patch code is a pattern of parallel, alternating black bars and spaces (a barcode) that is printed on a document. When scanning the document the patch code can be recognised and acted upon. The patch code may be recognised by the scanner itself (more usually in the top-end expensive scanners) or by the scanning or processing software or with a TWAIN or ISIS driver. Exactly what action is taken depends upon the design of any given system.
A patch code needs to be printed in a certain position, usually near the leading edge (feed-edge) of the document. This will vary depending upon the model of scanner used, and the orientation of the page. For this reason patch codes are often printed on all four edges of the page. Some scanners (such as the Kodak i800) require the patch code to be printed parallel to the feed-edge, other scanners (such as the Kodak i5000) require the patch code to be perpendicular (at right angles) to the feed-edge.
A typical use of a patch code is distinguish where one document ends and another begins when a pile of documents are loaded into the sheet-feeder (ADF) of a document scanner.
