Xerox 6180N Generic MICR Fundamentals Guide - Page 111
requires a 0.0008 inch/0.02 mm spot size and a 1200 dpi - noise
UPC - 095205425307
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Quality control • Character placement (0.125 inch/3.175 mm interval) - MICR line registration is controlled by the right edge of a single Transit character that is nominally 5.625 inches/ 142.89 mm from the reference edge. - Transport speed calibration accuracy, speed variations, and document slippage over this distance contribute to errors in MICR tester measurements of horizontal MICR line placement. - MICR testers can not measure vertical MICR line placement. NOTE: These errors and limitations never occur with a MICR Position and Dimension Gauge. Optical testing equipment usage The majority of automated optical MICR test equipment is aimed at document design, for which stringent limitations on density and contrast require sophisticated analysis. With different analysis software, this optical test equipment can be used to evaluate E13B font characters optically. However, there are some issues to consider before accepting it as a replacement for a MICR reticle on an eye loupe. • The optical test equipment does registration, character spacing, and character alignment well, because these tolerances-0.0625 inch/1.588 mm, 0.010 inch/0.254 mm, and 0.020 inch/0.508 mm respectively-are within the resolution limits of all scanners. However, MICR dimensional tolerances are ±0.0015, so the measuring device would require twice this resolution to sense the tolerance. This requires a 0.0008 inch/0.02 mm spot size and a 1200 dpi sampling rate. It may be argued that the tolerance is 0.003 inch/0.076 mm-the sampling rate of a 300 dpi scanner; but that is a cumulative tolerance for the two sides of a stroke. A 300 dpi scanner can evaluate only 0.0066 inch/0.168 mm tolerances well. • All dimensions are referenced to the "average edge," defined as the line that bisects any edge noise so that half the black area is on each side. The eye does this well, but automated scanners do not have the processing advantages of an eye. They need to resolve the edge noise due to the Yule-Neilsen effect, which causes an unresolved object to appear darker than the amount of ink coverage would predict. Generic MICR Fundamentals Guide 6-25