The bottom line on all checks printed and used in North America (and many other countries worldwide) is printed using a special font called MICR (short for Magnetic Ink Character Recognition). MICR is usually pronounced My-ker. The bottom line on a check must always be printed in the MICR typeface using a special magnetic ink.
The MICR line on a check allows the check information to be automatically read by inexpensive machines. This is the only way that huge numbers of checks can be processed each day.
Printing MICR is a very demanding. MICR line printing needs to be accurate to better than 1 part in 1,000! Your magnetic toner must stay on the paper under adverse conditions and have a specific signal strength.
The American National Standards Institute (ANSI) has a committee that develops all MICR printing standards. The ANSI committee has mandated precise requirements for MICR fonts, toner signal strength, MICR registration, toner adhesion, and for paper grain and moisture content. A similar Canadian group issued the CPA 006 standards for Canada.
There are two published standards for MICR: the first covers printing specifications for MICR (ABA 092200) and the second covers printing placement and locations (ABA 092700). These standards that can be ordered from the American Bankers Association (ABA) in Washington, D.C.
The MICR typeface has only 14 characters in it: the numbers 0-9, and four special symbols- Transit, Amount, On-Us, and Dash. Since MICR has only 14 characters, you can not print an entire check using just this font!
MICR characters are fixed width. Each number or symbol occupies exactly 1/8 of an inch. The actual numbers or symbols themselves have one of 5 different widths, and must be positioned exactly within the fixed character cell. If the numbers or symbols aren't positioned correctly, then certain pairs of numbers or symbols will not read correctly.
The MICR line at the bottom of a check encodes three or four separate items. If the check is longer than 6.5 inches, the left most field is the Auxiliary On-Us. It usually has the check number in it. If the check is 6.5 inches or less in length, this field is not present.
The next area (to the right) is the Transit field. This identifies the bank or institution. Next, (to the right), is the On-Us field, which is usually the business or person's bank account number. Finally, the right most area, which appears blank when the check is printed, is the Amount field. The check amount is filled in by the bank or another processing authority.
All MICR fonts must meet ANSI standard X9.27-1995. MICR line positioning is specified by ANSI standard ANS X9.7-1990. Fonts which don't meet these standards will cause checks to be rejected by banks. Note that some firms that sell MICR fonts have never read these standards, and their fonts will cause problems with your checks.
MICR, or E-13B, is also used to encode information in other applications like: sales promotions, coupons, credit cards, airline tickets, insurance premium receipts, deposit tickets, and more.