Canon MF720 Series Service Manual page 45

Toner cartridge
Bias
● Execution timing
The table below lists the execution timing and duration of each control.
No Executiontiming
.
1 Power-ON
2 Toner cartridge replacement
3 Environmentalchanges
4 After the pre-defined counts
printed
5 After the pre-defined time
elapsed
6 Resumed from sleep (after 8
hours or more)
7 Full correction
8 Quick correction
9 Copy image correction
● Image density correction control (D-max control)
This control is to stabilize the print image density.
The DC controller PCB triggers D-max control under the pre-defined conditions.
1. Measure the density detection patterns for each color on the ITB.
Laser scanner unit
ITB unit
High-voltage
power supply PCBs
Auto-gradation
D-max
correction control
Reader unit D-half
Duration D-max
Approx.195sec- Yes
onds
Approx.195sec- Yes
onds
Approx.195sec- Yes
onds
Approx.195sec- Yes
onds
Approx.195sec- Yes
onds
Approx.100sec- Yes
onds
Approx.100sec- Yes
onds
Approx.100sec- Yes
onds
Approx.100sec- Yes
onds
Color
displacement/density
sensor
Signal from color
displacement/density signal
Video signal
Color displacement
correction control
D-half Color dis-
placement
correction
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes -
Yes -
Yes -
Yes -
37
2. Technical Explanation
Remarks
Executed at initial rotation
Executed at initial rotation
Executed after job completionDe-
tected by the environment sensor
Executed after job completion
Executed after job completion
Executed after job completion
upon resumed
Executed by users