MICR (usually pronounced as 'My-ker') - Magnetic Ink Character Recognition - is a character recognition system that uses special ink and characters. When a document that contains this ink needs to be read, it passes through a machine, which magnetizes the ink and then translates the magnetic information into characters.
The bottom line on all checks used in North America (and many other countries worldwide) is produced using a MICR. The MICR line on a check allows the check information to be automatically read by inexpensive machines. This secure, high-speed method of scanning allows a huge numbers of checks can be processed each day