2-50 Phaser 6128MFP Service Manual
Theory of Operation
Image Data Flow
The image data from the media set on the Scanner or ADF goes through the
following components before it is printed at the Engine section.
Document Scanning Steps
A CCD Image Sensor is used to read image data from the media. The CCD Image
Sensor output is adjusted to ensure the image reading is stabilized. Adjustment
includes Automatic Gain Control (AGC) and Automatic Offset Control (AOC).
Reference data for adjustment is collected and used to perform compensation on
the read image data. Compensation includes shading, white variation, and black
variation compensations. These adjustment and compensation steps are
described below:
1. AGC (Auto Gain Control): White Level Variation Adjustment
During AGC, the Scanner Assembly is moved to the position of the white
reference plate, and the Exposure Lamp is illuminated. The light reflected from
the white reference plate is read by the CCD Image Sensor as the white
reference value, which is used to adjust the CCD Image Sensor output.
2. AOC (Auto Offset Control)
AOC is performed by turning Off the Exposure Lamp after AGC. This state is
read by the CCD Image Sensor as the black reference value, which is used to
adjust the CCD Image Sensor output. (The order of AGC and AOC adjustment
depends on the model.)
3. Shading Compensation
Shading compensation compensates for pixel-by-pixel sensitivity variations
and the non-uniformity of lamp light in the fast scanning direction. The AGC
and AOC adjustment values are used to compensate for the image data read
by the CCD Image Sensor.
Media
CCD Image Sensor (Scanner Assy)
Scanner Controller Board
Controller (Image Processor Board)
Laser Unit
Drum (CRU)
Scanner
Engine
s6128-049
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