Specifications

13-11. Developing Bias
•
A negative voltage (V
B
= developing bias voltage) is applied to the 1st and
2nd Sleeve/Magnet Rollers to prevent a foggy background on the copy.
The amount of toner attracted onto the surface of the PC Drum depends on
how much lower the PC Drum surface potential (V
I
) is than V
B
after
exposure.
•
A developing bias voltage of DC-270V is applied to the two Sleeve/Magnet
Rollers by PC Drum Charge HV HV1.
•
The developing bias is turned ON or OFF by the signal output from pin 75
of IC5A on Master Board PWB-A.
<Developing Bias ON Timing>
The developing bias output of HV1 turns ON at the same time when the PC
Drum Drive Motor is energized (p. M-26).
<Developing Bias OFF Timing>
The developing bias output of HV1 turns OFF approx. 1550 msec. after
Scanner Control Processor Board PWB-J has output a SCEND signal.
1st Sleeve/Magnet Roller
2nd Sleeve/Magnet Roller
1075C10MAA
M-90