Image Stabilization Control - Canon imageRUNNER ADVANCE C255 Series Service Manual

Image Stabilization Control

■ Overview
Image failure due to change of the environment or deterioration of the Photosensitive Drum is prevented to ensure stabilized
print.
Related alarm codes
• 10-0006: Patch Sensor error 1
• 10-0007: Patch Sensor error 2
■ D-max Control
Determines the optimal laser output.
Control timing
• When replacing the Drum Unit
• At paper interval or last rotation on a specified print basis (200 sheets or more)
• At the last rotation after printing when the difference in temperature/humidity from the last execution exceeds the specified
value
• At initial rotation for PASCAL Control or D-half Control
Control description
1. The Main Controller PCB forms the patch pattern of the target color on the ITB.
2. The Registration Patch Sensor Unit (Front) (UN31) and Registration Patch Sensor Unit (Rear) (UN32) measure the density
of the patch pattern.
3. On the basis of the measured density, the developing bias, primary charging bias, and laser output for each color are
corrected to achieve the target density.
■ PASCAL Control
Gradation density characteristics on the image are stabilized.
This control is executed when auto gradation adjustment (full adjustment) is executed. Gradation density of the patch pattern on
the test print is scanned by the Reader to create an image density correction table.
The foregoing table corrects image gradation density characteristics which change according to the environment change and
deterioration of the Photosensitive Drum.
Control timing
When auto gradation adjustment (full adjustment) is executed ([Settings/Registration] > [Auto Adjust Gradation] > [Full Adjust])
Control description
1. When the specified conditions are satisfied, the Main Controller PCB prints 3 types of memorized test prints (patch pattern).
2. Place the test prints in the Reader.
3. The reader scans the gradation density of the patch pattern from the test prints.
4. The Main Controller PCB creates an image gradation density correction table from the gradation density data of patch pattern
scanned by the Reader.
NOTE:
The following 3 types of patch patterns are formed with this control:
• A pattern for copy (39 patches for each color)
• A pattern for text (39 patches for each color)
• A pattern for photo (39 patches for each color)
Related service mode
• Enable/disable display of the dedicated mode for Plain 3, Recycled 3, and Heavy 1/2/3:
COPIER > OPTION > DSPLY-SW > HPFL-DSP
■ D-half Control
Optimal image gradation is determined.
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2. Technology