Functional Overview
DC Controller/Power System
High Voltage Power Distribution
a
The High Voltage Power Supply circuitry, located on the DC
Controller PCA, applies an overlap of dc and ac voltage to the
primary charging roller and the developing cylinder. This circuit
also applies a positive or negative dc voltage to the transfer
charging roller according to the instructions from the CPU on the
a
DC Controller PCA.
This circuit also controls the image density by changing the
primary ac voltage and the developing ac bias according to the
image density signal from the Formatter.
Figure 5-5 shows the timing of the high voltage power supply.
Power ON
7
WAIT ISBY!
(U.,? second)
lNTR
J
PRINT
LSTR
ST8Y
PRINT s,gnal (/PRNT)
\
—
VERTICAL SYNC
7
signal (f70P)
I
,
i , n
Matn rmbr
~1.7t021
I
—
Scanner motor
I
042
Im
PnrnarY voltage (AC) I
P,imar~ voltage (DC)
I Ill
I
t
Develwing bias (AC)
I
~
1
Developing bias (DC) I
I%H + I@%l
I
,-071
Transfer voltage
~
Laser diode
I
,
lll[lllllll!~llllilll
●
Note: The transfer vcdtage changes according !0 the print sequence as follows:
-:
Bek3en-fxigebL9s (Iowerpositw voltagethan the pr,nt bias isap,pleototfw Wa”s[ercharging
roller to prevent the damage of the photosensmve drum)
-: Negative bias (negative voltage is appli~d to the transfer charging roller for cleaning)
a
m: Print bms (POSMW vokage is app,edtofhetrans ferchargi”g mlerto tm”sterttw toner on the
photosensitive dmm sudsce to the paper)
Figure 5-5 High Voltage Power Timing
o
5-11
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