Table of Contents
Advertisement
Operating Principks
After the main motor has been activated for 0.06 secmds, the laser diode is fbrcibly activated h
0.74 seconds. At the same time, the laser emission power is adjusted.
LDATA
I
LDLVL
After the main motor (Ml) has been driven fix 0.0S seconds, the laser diode is forcibly activatd for
seconds, during which time the laser diode emission is detected. If the LDVR1 signal deviates
0.74
from the specified value during this period, the laser diode is assumed to be judged as
malfunctioning.
Bias Voltages and Laser Drive Timing
2.1.2.6
Figure 2-24 is a diagram of the drum charge, image transfer, and doctor blade bias voltages. This
figure also shows the developing bias voltage control arcuit. These bias voltages are generated
from the +12 VDC on the high voltage supply board (PWB-F). If the printer detects a case open
condition, the interlock switch is set to off, which cuts the +12 VDC and in turn cuts the bias
voltages.
These bias voltages are controlled by the main board (C144 MAIN). The CHXJN signal is the
image transfer (roller) bias voltage control. While this sigmd is LOW, the image transfer roller is
charged to 3.5K VDC by the high voltage supply circuit. While this signal is HIGH, the image
transfer roller is chargwi to -0.5K VDC. The CH1:ON signal controls the dmm charge. While this
signal is LOW, the PC drum is charged to -1.2K VDC.
voltage level (about -300 VDC) using analog data.
developing bias voltage level.
Inter Lock
+12 VDC
Power Suppry
Board
Figure 2-24. High Voltage Supply Block Diagram
2-16
I
Main
Board
+12 VDC
. . . . . . . . . . . . . . . . . . . . . . . . .
0.74
The image density is controlled by the
High Voltage Supply
Board
Image
Bias (CH2)
Developing
:
---
. . . . . . . . . . . . . . . . . . . . . . .
Bias
about -300 VDC
. . . . . . . . . . .
Doctor Blade Bias
:
---
Drum Charge (CH1)
-1.2 K VDC
[sec.]
Transfer
-0.5 K VDC
Of
Rev. A
Advertisement
Chapters
Table of Contents
