DRUM UNIT
2-49
SM A229
Detailed
Descriptions
2.5 DRUM UNIT
2.5.1 PROCESS CONTROL
Overview
The drum potential will gradually change because of the following factors.
•
Dirty optics or exposure glass
•
Dirty charge corona casing and grid plate
•
Changes in drum sensitivity
To maintain good copy quality, the machine does the following just after the main
switch has been turned on (if the fusing temperature is less than 100
°
C and SP3-
901 is on).
1) Potential Sensor Calibration
2) V
SG
Adjustment
3) V
G
(Grid Voltage) Adjustment
4) LD Power Adjustment
5) V
REF
Update
This process is known as ‘Process Control Initial Setting’. The rest of this section
will describe these steps in more detail.
Processes 1, 3, and 4 in the above list compensate for changes in drum potential.
Processes 2 and 5 are for toner density control; see the “Development and Toner
Supply” section for more details.
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