Oki B6200 Maintenance Manual page 621

5.3
EP CARTRIDGE
The EP CARTRIDGE is also known as CRU (Customer Replaceable Unit), and is made up of the
following five components.
• Drum
This is a cylinder of aluminum and coated with a photoconductive material. Because of this
photoconductive coating layer, electric charges are retained on the surface in the dark, and
electrical conduction occurs when exposed to light.
• BCR (Bias Charge Roll)
This uniformly distributes electric charges over the drum surface, and erases a charge-reduced
pattern remaining from the previous cycle.
• Magnet Roll
This holds toner as a thin layer on the surface of this roll, and acts to transport the toner into the
gap between the drum and Magnet Roll. The toner is supplied to the Magnet Roll by the Agitator
in the Toner Compartment.
• CM Blade (Charging and Metering Blade)
This spreads the toner into a thin layer over the Magnet Roll, and applies negative charges to the
toner triboelectrically.
• Cleaning Blade
This scrapes toner remaining after the transfer step off the drum surface.
BTR ASSY
The BTR of the BTR ASSY is in contact with the drum of the EP CARTRIDGE, and is driven by the
Drum Gear. When the paper moves between the BTR and Drum, the BTR applies positive charges
to the rear surface of the paper. The negatively charged toner image is attracted by positive charges
on the rear surface of the paper. Thus, the image is transferred from the surface of the drum to the
surface of the paper.
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Chapter 6 Principle of Operation