Ricoh A156 - Drum Charge; Overview

3. DRUM CHARGE
3.1 OVERVIEW
This copier uses a drum charge roller system instead of a corona wire
scorotron system to charge the drum. For the copy image area or during
process control, the drum charge roller [A] contacts the surface of the OPC
drum [B] to give a sufficient negative charge.
The drum charge roller system has the following advantages over the corona
wire scorotron system:
• The amount of ozone generated during drum charging is less than 1/10
of that for a corona wire scorotron system.
•
The applied voltage is 1/2 ~1/3 that of a wire scorotron system.
•
The efficiency of drum charging is high.
Thanks to the above advantages, no ozone filter is required for this copier.
The CB high voltage supply board [C] gives a constant dc voltage of –1500
V (–1300 V for the V
SP
pattern) to the drum charge roller at the charge roller
terminal [D]. This gives the drum surface a negative charge of –900 V (–600
V for the V
SP
pattern).
[C]
[D]
[B]
[A]
A156/A160/A162 2-34 STM