MICR character spacing requirements
Character spacing algorithm for 300 dpi
Fixed pitch and proportional font spacing
Generic MICR Fundamentals Guide
Reader sorters have timing limits that prevent them from
handling extreme variations in character spacing. The average
spacing requirement for MICR characters is 0.125 inch/6.4 mm
per character (8 characters per inch).
The MICR specifications have a tolerance on the 0.125 inch/6.4
mm spacing requirement of ± 0.010 inch/.3 mm. Specifications
also state that the accumulated error must not exceed field
boundaries, shown in table 4-1. MICR characters are right
justified and the numbers are read from right to left. This means
that you might need to pad the MICR line with leading blanks so
that the numbers start in the correct position.
MICR printing systems print at 600 or 300 dots per inch. At 600
dpi, there are no issues with character spacing. 600 dpi can be
divided evenly by 8 characters per inch, resulting in 75 dots per
However, 300 dpi, when divided by 8 characters per inch, results
in 37.5 dots per character. The system cannot print half a dot, so
it cannot print each character at exactly 8 characters per inch.
You can achieve an average of 37.5 dots per character by using
a proportional spaced font with a spacing algorithm that places a
space of one dot after every second character. In other words,
two characters of 37 dots are printed, followed by a one-dot
space, then the sequence is repeated. This algorithm is used
extensively in high volume printing installations.
The relationship between the input character and the output
character or space is shown for proportional spaced fonts in
table 4-3, and for fixed pitch fonts in table 4-4.
NOTE: The relationship between the input character and the
output character may differ slightly from these tables for some
Xerox MICR products. These differences are primarily found with
the revision control character (?) and the special symbols.