Epson AcuLaser M2000D, Service Manual

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AcuLaser M2000D/M2000DN/M2010D/M2010DN Revision B
OPERATING PRINCIPLES Technical Explanation of Print Process 20
Confidential
2.2 Technical Explanation of Print Process
2.2.1 Charging
DRUM SECTION
The durable layer of organic photoconductor (OPC) is coated over the aluminum
cylinder base. The OPC tend to reduce its own electrical conductance when exposed to
light. After a cyclic process of charging, exposure, and development, the electrostatic
image is constituted over the OPC layer. Since the OPC is materialized by resin, it is
susceptible to damage caused by sharp edges such as a screwdriver, etc., resulting in a
print quality problem. Also, finger prints can cause deterioration of the OPC layer,
therefore, the drum (in the drum unit) must be handled with care. Substances like water,
alcohol, organic solvent, etc., should be strictly avoided. As with all other OPC drums,
the exposure to a strong light source for a prolonged period can cause a print quality
problem. The limit is approximately 500 lux for less than five minutes. If the drum
(drum unit) remains removed from the printer, it should be stored in a cool, dark place.
Figure 2-5. Drum section
MAIN CHARGER UNIT
As the drum rotates in a “clean (neutral)” state, its photoconductive layer is given a
uniform, positive (+) corona charge dispersed by the main charger wire. Due to high-
voltage scorotron charging, the charging wire can get contaminated by oxidization
after a long run. Therefore, the charger wire must be cleaned at a specific interval.
Cleaning the charging wire prevents print quality problems such as black streaks.
Figure 2-6. Main charger unit
Figure 2-7. Drum unit and main charger unit block diagram
Drum Drum shaft
Drum cover A
Drum cover B
Main charger grid
Main charger
wire cleaner
Main charger wire
Main charger shield
Main charger wire
Main charger shield
Main charger grid
Drum
HVPS
Main charger output
Zener
PWB
M