As a check travels through the check clearing system, it passes through machines called reader/sorters. As the check passes through the machine, the reader/sorter sends a magnetic charge to the check, which allows it to read the information contained within the MICR line very quickly...checks pass through a reader/sorter at a speed of 70mph! The Federal Reserve and all banks require that checks be printed with MICR toner for ease of processing. If a negotiable document is printed with regular toner, the reader/sorter will reject the check, forcing a manual process for clearing the check. As a result the company who printed the check will be charged a fee per item rejected. This consequence is the reason why it is important that companies print checks with MICR toner.