The blank check consists of three parts. The upper third is the check itself. The bottom third is used as a Check Authorization Notice that you mail to your customer to inform them that a duplicate bank draft was created and deposited as authorized by them for this transaction. Keep this section as a record of the transaction. The MICR characters at the bottom of the check must be readable magnetically, even though much of the banking industry is now using optical scanners.
All laser toners have magnetic qualities, but the level of magnetism is low.
If your bank notifies you of a problem, then you will need to purchase MICR toner for your laser printer. ChekFaxx has MICR toner cartridges available for many popular laser printers. MICR stands for Magnetic Ink Character Recognition. These are the numbers you see at the bottom of every check. Electronic scanners read the printed magnetic qualities of these numbers to process the check.