EN Image defect details 171
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• Observe the following from the test sample:
– Check the spacing or “pitch” between the defects.
– Check to see if the defect spans all color planes.
– If the defect is in all color planes, does the defect produce a
straight line through all color planes or does it move from one
color plane to the next?
– If the defect moves from one color plane to the next, measure
the amount it moves. This movement amount is called the
“procession.” Keep in mind the print order is K-M-C-Y. Measure
the procession from K to M or M to C, not K to C.
CAUTION
Do not expose the drum to light for more than 15 seconds. The drum
is light sensitive, and exposure to light can cause permanent damage.
Banding — horizontal
• The imaging drum may have been exposed to light. (See “Sunburn”
on page 181.)
• The ITB may accumulate contamination on its rollers causing a
random mechanical banding. If you notice buildup on the rollers,
replace the ITB.
• As the developer rotates, the gap between the imaging drum and
the developer can vary slightly. This can cause toner to be
transferred lighter or darker every 37 mm. This defect is more
apparent in secondary colors. There is no workaround.
Banding — vertical
• The doctor blade on the developer can develop notches over time. If
you observe severe notching, replace the developer.
• As the imaging drum gets older, the charge roller doesn’t charge the
imaging drum as well as it used to. If you notice buildup or
contamination on the charge roller, replace the imaging drum.
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