Service manual

1.3.8 Gradation Pattern Development
The gradation pattern is developed with a fixed development bias.
1.3.9 Gradation Pattern Density Detection
The ID sensor detects the developed gradation pattern (12 grades for each
color), and the outputs are stored in memory.
1.3.10 Development Potential Calculation
The development potential (V
DP
) is the capability to attract toner to the drum
and can be shown as: V
B
- V
L
V
B
: Development Bias
V
L
: Drum potential after full laser exposure
See the above drawing for two examples.
The machine calculates the approximate present development potential from
the sensor readings. This consists of the following steps:
1. The machine converts the gradation pattern densities using the ID
sensor into an actual toner amount on the drum (referred to as "M/A") for
each grade of the pattern.
2. From the potential and ID sensor outputs, the machine then determines
the relationship between the drum potential and the amount of toner
developed on the drum. This is known as the development gamma factor.
3. The machine can now calculate the development potential that would be
required to obtain the ideal toner density on an area of the drum
developed with full laser power, under the machine’s present conditions.
Detailed
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PROCESS CONTROL
SM 2-9 A166/A187/A189
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