A Concise Guide to MICR and Associated Technologies
Magnetic Ink Character Recognition (MICR) was developed to
utilize the benefits of computer technology in the banking
industry. Prior to the use of a MICR line, check sorting by
account number was a manual process. Two systems were previously
used to handle the large numbers of checks processed in the
banking industry: Sort-A-Matic and Top Tab Key Sort.
The Sort-A-Matic system included 100 metal or leather dividers
numbered 00 through 99. Each check was placed in the
corresponding divider by the first two numbers of the account.
The sorting process was then repeated for the next two digits of
the account number, and so on. When the process was complete,
the checks were grouped by account number.
Under the Top Tab Key Sort system, small holes punched at the
top of the checks indicated the digits. For instance, the first
hole indicated the value of the first digits (0, 1, 2, 3...) A
metal "key" was inserted through the holes to separate all of
the checks with the same value in the first digit, and this step
was repeated for each digit until all the checks were sorted.
Both of these systems worked, but they were time-consuming. With
the advent of the computer and its movement from the laboratory
into the business world, a sorting and matching task seemed
ideal. Stanford University and Bank of America were the first to
successfully use computers to sort and match checks. They
developed what is now known as MICR. The Development of the MICR
Font
The MICR font was developed by Stanford University in
conjunction with Bank of America and approved by the American
Banking Association. The font is known as the E-13B font. E-13B
has a total of 14 characters: ten specially designed numbers (0
through 9) and four special symbols (Transit, Amount, On-Us, and
Dash).
The letter E indicates the fifth version considered. The letter
B indicates the second revision of that version. The number 13
is derived from the 0.013-inch module construction used for
stroke and character width. This means that all character
widths, both horizontal and vertical, are in multiples of 0.013
inches ranging from 0.052 to 0.091. The significance of this
will be explained more thoroughly later in this article. MICR
Readers
Three types of machines are used to read MICR characters. The
two that read the characters magnetically are referred to as
MICR readers. The third machine is an Optical Character
Recognition (OCR) reader.
E-13B characters are printed with toner containing iron oxide,
which is capable of being magnetized. MICR readers transport the
checks containing the E-13B magnetic characters past a magnet,
thereby magnetizing the iron oxide particles. The magnetized
characters then pass under a magnetic read head. The magnetic
field (flux pattern) caused by the magnetized characters
generates a current in the read head. The strength and timing of
this current allows the reader to decipher the characters.
Magnetic readers come in two types: single track (single gap or
split scan) and multiple track (matrix or pattern) readers.
Single-Track Reader Characteristics Single track uses a read
head with one gap to detect the magnetic flux pattern generated
by the MICR character. When a magnetized E-13B printed character
moves across the narrow gap of the read head, the electric
voltage caused by the magnetic flux from the character generates
a waveform unique to each character.
Multi-Track Reader Characteristics The multiple track reader
employs a matrix of tiny, vertically aligned read heads to
detect the presence of the magnetic flux pattern. The small
individual read heads slice across the character to detect the
presence of magnetic flux. This sensing of magnetic flux over
time produces a unique matrix pattern for each character.
An OCR reader does not use magnetic properties to detect the
E-13B characters. Instead, it uses a scanner to detect the
amount of light reflected from the character and the amount of
light reflected from the background. A photocell column detects
the presence of the dark area of a character. Waveform Theory
The readers move and read documents from right to left. The
right-hand edge of the character, as a result, is the first to
cross the read head. Analysis of the signal level created by
reading the character 0 will help explain this in greater detail.
As the
character moves from right to left under the read head,
the gap detects the magnetism of the first right-hand edge (edge
1). This results in the increase in magnetism and a positive
peak is created (peak 1). As soon as the right-hand edge moves
beyond the read head gap, no new magnetism is found, and thus
the wave form returns to the zero signal level.
At the second edge, the vertical read head detects a drop in
magnetism, which results in a -110 signal level at peak 2. Again
the waveform returns to zero until the next portion of the inner
ring of the character is detected. At this point (peak 3), an
increase in magnetism (+110) is indicated. Finally, the outer
portion of the character is read, resulting in a negative peak
(peak 4) of -130.
The placement of the vertical edges must occur in increments of
0.013 inches from the first right-hand edge. There are five
characters that have two positive and two negative peaks similar
to the character 0 and also appear in a
positive-negative-positive-negative format. They are 0, 2, 4, 5,
and the transit character, which are differentiated from one
another by the horizontal location of the peaks in the
waveforms. The peaks do require different amplitudes, but ANSI
standards allow them to vary from 50% to 200% of the nominal
amplitudes (Canadian standards allow them to vary from 80% to
200% of the nominal amplitudes). This is why the placement of
the waveform is so important and why the characters are shaped
unusually. What Affects the Signal Level?
Signal level can vary based on a number of factors. The amount
of iron oxide (concentration) that is present in the character
will affect the signal level. This is a function not only of the
toner itself, but also of how it is laid on the paper and the
pile height, which can be controlled by numerous other cartridge
components (i.e., "hot" OPCs).
The taller the vertical edge of the character, the taller the
peak (either positive or negative). A vertical edge that is not
regular and/or not vertical will result in a reduction in the
amplitude of the peak and will flatten the peak out.
Keys to proper waveform detection are: * All peaks in a
character's waveform must be detected. The reader sorter must
know that the peak is there. * The peak must be located at or
near its anticipated location. * No significant "extra" peaks
can be present. * There cannot be wide variations in the signal
levels of peaks within a character. What to Look for in MICR
Printers and Consumables
Printers that are used for MICR printing must have a unique MICR
font that is modified to suit the unique printer engine, and it
must be modified to the pixel level to match the magnetic toner
provided for that printer. This is essential to ensure the
correct waveform, dimension, and signal strength when a check is
printed with the correct MICR characters. In addition, the MICR
font must meet ABA-X9 standards to ensure acceptance of your
checks by banking institutions.
The magnetic MICR toner that you choose must be specifically
designed for the particular print engine in the printer. Ensure
the toner has been thoroughly tested for consistent signal
readings, image permanence and uniformity, and excellent edge
acuity. Toner coverage must be solid with no extraneous toner
lay down.
OEM cartridges are always a safe (but more expensive) bet. If
you buy a "compatible" brand, ensure it has a new OPC drum, new
primary charge rollers (PCRs), a new black velvet magnetic
sleeve, and new image wiper blades. The hopper system must be
filled with high-quality, low-abrasion MICR toner.
The vendor you choose should use the latest and most advance
MICR test equipment, such as a Verifier and Golden Qualifier to
conform to ANSI X9 Standards. It is also recommended that the
systems exceed U.S. and Canadian check printing standards.
About the author:
Charles Katz is CEO and founder of Printerm Datascribe Inc.,a
distributor of band, shuttle matrix, dot matrix, and ion
deposition printers for various manufacturers. In 1992, Printerm
started its R&D department to develop innovative MICR secure
laser check printers, MICR fonts, MICR toner, MICR check
software, removable security flash cards, and secure digitizing.
Reproductions of this article are encouraged but must provide an
link http://www.printerm.com
Written by: Charles Katz
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