Description Of Printing Process Techniques - Brother HL-4200CN Service Manual

1.3

Description of Printing Process Techniques

1.3.1 Charging with electricity
In the charging process, the drum surface rotating at a constant speed is charged
uniformly with negative electricity by discharging of RTC (Rubber Tube Charge: Charged
film).
This process is performed in parallel for yellow, magenta, cyan and black colors.
•
The RTC is kept in contact with the drum and rotates following the rotations of the
drum.
RTC is a conductive roll, receives discharge voltage from HVPS (High Volume
Power Supply) and discharges at minus DC voltage.
•
The drum surface is uniformly and negatively charged with DC bias voltage.
The drum surface is optical conductor (which is insulator in a dark place and
conductor when receiving light) and the drum inside is composed of conductor.
•
The Refresher is a conductive brush, and it receives negative DC voltage from the
HVPS to catch the toner of reverse polarity returned to the drum via IDT. Also, it
removes discharge products.
HVPS
RTC
-
-
-
-
+
-
+
-
+
Drum surface
Fig.3-5
III-4
Refresher
Optical conductor
Conductor
Drum
Fig.3-4
Electric potential
on drum
-V
0
Fig.3-6