Ricoh B132 Service Manual page 752

LASER UNIT
This diagram shows a close-up view of the sub-scan test pattern.
K is the reference, and the positions of CMY are adjusted with reference to the K
pattern.
The CMY patterns are at constant intervals, but the K pattern overlaps the CMY
patterns as shown.
The MUSIC sensor response is measured. The output is the lowest when the K
pattern fully overlaps the color pattern (the dotted lines in the diagram cross at this
point). This is the "Actual" position as shown in the diagram. But there is a "Target"
value in the machine's software (an example is shown on the diagram; this is not
the real target, it is just an example to explain the process). The machine compares
the "Actual" and "Target" values, and adjusts the main motor speed in response to
the results of this comparison.
B132/B200
Vertical Position in
the Test Pattern
Sensor Output
B132D970A.WMF
6-50
Target
Actual
SM