Epson AcuLaser C1900, Service Manual

Page: 93 / 270

EPSON AcuLaser C1900/AcuLaser C900 Revision B
Operating Principles Image Stabilization Control 93
2.3 Image Stabilization Control
The image stabilization control as described below is performed to stabilize the output
images.
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AIDC detection
Measures the amount of toner adhering to the transfer belt and stabilizes color
reproducibility.
1. An LED radiates infrared rays onto the toner pattern on the transfer belt.
2. The light receiver detects the infrared rays reflected by the toner pattern on the transfer
belt.
3. A voltage corresponding to the intensity of the reflected light is output to the Main
Board Assy (PWB-A).
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Outline of AIDC control
AIDC control as described below is performed to ensure image stabilization.
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Ds correction control
Sets an optimum development bias to prevent image fogging or uneven density.
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LED light adjustment control
Adjusts the quantity of light emitted by the LED to ensure a constant output value
from the sensor relative to the surface of the intermediate transfer belt to which no
toner is adhering, in order to control the fluctuation in characteristics the AIDC
sensor which can occur due to the lapse of time or dirt.
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Belt surface level correction control
Measures the variation of the reflection factor of the intermediate transfer belt due
to the lapse of time and uses the measurement result for correction in the laser light
adjustment control and gamma correction control.
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Solid color toner adhesion control
Adjusts the ratio of the pulse width of development bias to ensure a constant
amount of toner adhesion (amount of development) formed on the OPC drum
relative to 100% solid image.
Table 2-4. Image Stabilization Control
Purpose Control Sensor
To stabilize image density AIDC control AIDC sensor (AIDC detection)
To stabilize pixel depth
To stabilize transfer
Transfer output control Temperature/humidity sensor
Toner Adhesion Reflected Light Output
Much Small quantity Low
Little Large quantity High
AIDC sensor
Table 2-5. AIDC Control Items
Control Description
Ds correction control Sets development bias.
LED light adjustment
control Adjusts the quantity of light to be emitted by the LED.
Belt surface level correction
control Used for laser light adjustment and gamma correction control.
Solid color toner adhesion
control Keeps the amount of toner adhesion to the OPC drum at a
constant level.
Laser light adjustment
control Ensures a constant level of black line reproduction and white
line reproduction.
Adjusts the quantity of laser light for a certain amount of toner
consumed.
Gamma correction control Corrects the pixel depth by the controller.