April, 2007 ADDITIONAL INFORMATIONS
4-85
4.4.5 DIRTY BLACK LINE IN CUB-SCAN DIRECTION OR DIRTY BACKGROUND
SYMPTOM:
1. A dirty black line [A] shows in the sub-scan direction in single color (C, M, Y or
K).
2. Dirty back ground in halftone image.
CAUSE:
Drum charge roller becomes dirty. This can be a common occurrence especially in
high copy volume machines, or, machines used under low temperature/low
humidity conditions (temperature 10 °C or 50 F/ humidity 15%).
ACTION:
Remove the drum charge roller from the PCU, and clean it according to the
procedure explained below.
1. Remove the PCU, whose color has the symptom. (See “APPENDIX” of this
section for details on how to print out the K, M, C or Y halftone test pattern).
NOTE: Make sure you put the removed PCU on the PCU stand when you do these
procedures. Also, make sure to place a sheet of paper on the PCU to not
let the OPC drum gets exposed to light.
Paper Feed Direction
[A]
<<Example of Cyan halftone image>>