Canon NP2120 Service Manual page 68

Transfer Corona Current and
the Grid Bías Voltage
Figure 3-27 shows the circuii which controls the
current for the primary/transfer corona unit and the
functions:
and OFF;
corona unit.
Theoutputtotheprimarycoronaunit
toa constant value; the shield current is controlled to
eliminate the effects of environmental changes on
The primary corona current and transfercorona
current are turned ON and OFF by the high-voltage
The grid bias voltage level is switched by the grid
bias control signa1 (GRDON).
D C controller P C S
1
flows from the primary corona unit because of
backsignal totheifferentialamplifiercircuit increases
iscontrolled
current to a specific value.
If an over-current flows on the output side of the
high-voltage transformer used for primary/corona
the flow to a specific value.
C A N O N NPZ12O/ZMO REY.0 M A Y 1990 PRINIKI I N JAPAN IIMPRIME AU JAPONI
generatorcircuit goes ON.