Canon imageRUNNER ADVANCE C350 series Service Manual page 115

2
Technical Explanation > Image Formation System > Controls > Image Stabilization Control
Output of patch pattern data
Patch pattern is created
Patch patterns (2 types)
Printed test patterns
are scanned by the reader
(Y) PASCAL correction data
Actual gradation
characteristics
Y63 Y64
100
Output of density data
Ideal gradation
Y2
characteristics
PASCAL correction table is
Y1
created (Y,M,C,BK)
0
100
Data output (M-CON)
100
Ideal gradation
characteristics
Gradation
characteristics
after correction
0 100
Data output (M-CON)
2 Technical Explanation > Image Formation System > Controls > Image Stabilization Control
Start
Main Controller PCB (UN81)
DC Controller PCB (UN04)
printed on paper
Registration Patch Sensor Unit
(Front,Rear) (UN31,UN32)
Patch scanning
DC Controller PCB (UN04)
Main Controller PCB (UN81)
F-2-96
● D-half Control
Optimal image gradation is determined.
Control timing
1) During installation and when replacing the Drum Unit
2) At last rotation on a specified print basis (1000 sheets or more)
3) At last rotation when PASCAL control is executed
Control description
1) Main Controller PCB outputs patch data in each color (Y, M, C, and Bk) to the DC Controller
PCB.
2) From the data above, the DC Controller PCB forms patch pattern in each color (Y, M, C,
and Bk) on the ITB.
3) The DC Controller measures the patch pattern by the Registration Patch Sensor Unit (Front)
(UN31) and the Registration Patch Sensor Unit (Rear) (UN32) and the result is returned to
the Main Controller PCB.
4) Based on the data above, the Main Controller PCB executes gradation correction to obtain
ideal halftone image.
NOTE:
The following 3 types of patch patterns are formed with this control:
• A pattern for copy (9 patches for each color)
• A pattern for text priority (9 patches in each color)
• A pattern for photo priority (8 patches in each color)
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