Functions - Toshiba e-STUDIO 2555C Service Manual

3.12.3

Functions

1. Drum
Drum is made of a cylindrical aluminum base coated with thin film of organic photoconductive
substance. Photoconductive object becomes insulative (high electrical resistance) when it is not
exposed to lights and becomes conductive (low electrical resistance) when it is exposed to lights.
This object is called photoconductor.
2. Drum cleaner unit
- Cleaning blade
This blade is pressed against the drum surface with a constant force and scrapes off the residual
toner on the drum surface.
- Recovery blade
This blade prevents the toner which was scraped off by the cleaning blade from being scattered
to the outside.
- Toner recovery auger
This auger carries the residual toner scraped off to the waste toner box.
3. Main charger
The main charger in this equipment consists of a metal rod with U-shaped section, insulated
terminals at both ends of the rod and a needle electrode attached between them. When a high
voltage is applied to the needle electrode, the air around it is charged (ionized). The ionized air then
flows into the drum causing it to be charged. This phenomenon is called "corona discharge". At the
same time, a control bias is applied to the main charger grid to control the charging amount. In a
dark place, negative charge is evenly applied onto the drum surface by the corona discharge and
this grid. In addition, a cleaner is installed to clean up the dust attached on the needle electrode.
- Needle electrode
The needle electrode has aligned needles and their points perform the corona discharge.
These points (electrodes) discharge toward the drum in one direction to realize the more
efficient discharging comparing to the charger wire which discharges in a radial direction.
Therefore, the needle electrode enables to reduce the ozone amount.
4. Drum thermistor (THM3, THM4)
Since the photoconductive characteristic of the drum surface changes depending on the
temperature of the drum surface, the drum thermistor detects the temperature of the drum surface
and controls to gain the charging potential according to the environment.
5. Discharge LED (ERS-Y, ERS-M, ERS-C, ERS-K)
Discharge is a process to decrease or eliminate the charge on the drum surface.
The residual charge on the drum surface is neutralized and eliminated. Electrical potential of the
drum surface is fixed to a certain amount before the drum is charged.
6. Temperature/humidity sensor (S10)
This sensor measures the environment inside the equipment. The values of the temperature and
humidity detected inside the equipment are output to the LGC board.
7. Ozone filter
Ozone produced by corona discharge of the main charger is exhausted through this filter.
The catalyzer of the ozone filter degrades the ozone.
8. Ozone exhaust fan (F2)
This fan exhausts air through the ozone filter-1.
e-STUDIO2555C/3055C/3555C/4555C/5055C
OUTLINE OF THE MACHINE
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