Olivetti d-Color 201MF Theory Of Operation page 34

Theory of Operation Ver. 1.0 Sep. 2008
(2) Color shift due to overall scaling error in the main scan direction
• If the image of each color (Y, M, C) and the image of black (K) vary in length in the main
scan direction, changing the clock frequency of the laser diode can correct the length dif-
ference in the main scan direction. Color shift correction needs to be performed sepa-
rately for the respective colors (Y, M, C).
• Color shift correction control is activated when the image stabilization sequence is
started.
* When the image of magenta is longer than the image of black (K)
Transfer belt
Rotational
direction of the
transfer belt
(3) The Color shift in the sub scan direction
• If the image of each color (Y, M, C) is misaligned with respect to the image of black (K) in
the sub scan direction, changing the write start timing in the sub scan direction can cor-
rect the color shift. Color shift correction needs to be performed separately for the
respective colors (Y, M, C).
• Color shift correction control is activated when the image stabilization sequence is
started.
* When the image of magenta is misaligned with respect to the image of black (K) in the sub
scan direction
Rotational
direction of the
transfer belt
Y109670-2
Before correction
Color shift
Before correction
Transfer belt
Theory of Operation
8. Write section (PH section)
Color shift
Magenta (M)
Black (K)
Black (K)
Color shift
Magenta (M)
After correction
No color shift
A02ET2C631AA
After correction
No color shift
A02ET2C632AA
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