Charging Mechanism - Ricoh A028 Service Training Manual

OPC Charge

2.4.2 Charging mechanism

The Scorotron system is employed to supply a uniform
surface charge to the photoconductor. The charge
system is composed of looped charge corona wires and
grid wires (see illustration).
Output from the charge power pack goes to the charge
wire at (-)2.5mA constant current and to the grid wire at
approximately (-)650V constant voltage. In the process
control, the grid voltage is divided into 32 steps at a rate
of 28V/step.
Normally, (-)650V is applied to the grid wire as a set
value, but even if the discharge from the charge wire
varies as a result of contamination, the grid current
varies and the potential of the grid wire is maintained
constant. This is because the grid output is a constant
voltage operation. In this way, charge to the
photoconductor is stabilized.
2-38
Charge corona wires
Charge
power pack
Grid wires
Current flow:
--174V to --1,024 V
1 July 1994