Auto Gradation Control - Canon imagerunner C5180 Service Manual

9.5.9 Auto Gradation Control

Outline
The auto gradation control mechanism is used to correct image gradation by correcting the laser output so as to
obtain ideal gradation characteristics.
Full Correction:
Quick Correction:
User Mode
The machine uses 2 types of auto gradation correction mechanisms, combining the best mechanisms to suit
individual requirements.
Description
Image density
Actual gradation characteristics
1.45
0
Relationship between laser output
and image density
F-9-21
T-9-21
The machine knows the actual gradation characteristics based on the 64-gradation
density data collected from the scanner.
The machine knows the actual gradation characteristics based on the 9-gradation
density data.
T-9-22
Full correction
Start up
|
v
SALT-Dmax control
(determines developing DC, charging
DC, primary current levels)
|
v
PASCAL control
(prepares image correction table A)
|
v
Ideal
characteristics
255
Quick correction
Start up
|
v
SALT-Dmax control
(determines developing DC, charging
DC, and primary transfer levels)
|
|
|
|
|
|
v
Chapter 9
9-27