Determining The Optimum Laser Output; Laser Output Corrective Control - Canon imageRUNNER 7095 Service Manual

7.4.5 Determining the Optimum Laser Output

The machine determines the optimum laser output so that the drum surface potential (light area potential
VL) is identical to the target potential.
Potential sensor
Developing bias(DC)
Laser
Turn on the lamp at 80% of the reference
output determined at time of shipment.

7.4.6 Laser Output Corrective Control

If the optimum laser output cannot be determined after measuring the drum surface potential, the machine
starts its compensatory control sequence to determine the optimum laser output.
Continues to take measurements while varying
the laser output so that it will approach
Target VL
Potential sensor
Developing bias(DC)
Laser
The machine takes measurements multiple times
to determine the relationship between the drum
surface potential (VL) and the laser output.
VL3
VL2
VL1
60%
80% 100%
Laser output
195
WMUP WMUPR
Measurement(VL2) Measurement(VL1orVL3) Measurement (target VL)
80%
After measuring VL2, measures VL3 if VL2
is grater than the target VL; if smaller,
measures VL1.
VL1
VL3
VL2
VL-NG
193
WMUP WMUPR
60%
80%
or
100%
Compensatory control sequence started
If this measurement brings about
the target VL, ends the control;
otherwise, starts compensatory control.
Pw
60% or 100%
F-7-9
If the measurement is identical to the target VL, ends
control; executes measurement a maximum of 8 times,
possibly using an approximate value of the target VL.
VL-NG VL1 VL2 VL3
Pw8
Pw Pw1 Pw2 Pw3
Determines a laser output needed
to attain the target VL.
F-7-10
198
STBY
Determines the laser output (P)
needed to attain the target VL.
198
STBY
VL8
Chapter 7
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0010-8044
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