Specifications

9
DRUM CHARGING
9-1. PC Drum Charge Corona
•
The PC Drum Charge Corona of this copier is provided with two corona
wires and Scorotron grids, depositing a DC negative charge evenly across
the entire surface of the PC Drum.
•
When PC Drum Charge HV HV1 turns ON, a voltage of approx. DC-6kV
flows through the two wires and a corona emission begins. A grid voltage
(V
G
) is applied to the two grid meshes, thereby ensuring that the charge
level is maintained evenly across the entire surface of the PC Drum.
•
The grid voltage (V
G
) applied to the grid meshes is varied to compensate
for any drop in the surface potential (V
0
) which could occur with age. (For
more details, see page M-24.)
•
V
G
is controlled by the Constant-Voltage Circuit in HV1 to remain in the
range between DC−650V and −890V according to the Grid Control pulse
output from Master Board PWB-A. It is initially set at DC−770V.
•
The corona unit is provided with a mechanism that cleans its two wires at a
given timing. It effectively removes from the wires any toner and dust
particles which would otherwise cause uneven charging. (For more details,
see p. M-31.)
Grid Mesh
Corona Wires
PC Drum
Grid Mesh
1075M047AA
Corona Wires
PC Drum
Grid Meshes
HV1
V
G
DC (−) 6kV
GND
1075M048AA
M-28