Toner Life Sensor Circuit - Panasonic KX-MB2230JT Service Manual

6.12.16. Toner Life Sensor Circuit

1. General
This circuit detects whether the Toner is brand-new or secondhand.
And if Toner is detected as brand-new, after predetermined printing, Fuse, which is installed inside of the Toner is cut.
After cutting the fuse, the Toner is judged as secondhand, and Toner life counting starts.
This circuit consists of Fuse cut block and Toner type detection block.
2. Circuit diagram
TNR Contact Board
1st use Board
3. Circuit Explanation of Fuse cut block
When IC300_pinK26 is "H", Q608, Q609 and Q610 are turned on. Then current flows F99 through R687/R688. Conse-
quently Fuse is cut within 1 second.
R687 and R688 are supplied to protect Q608 and Q609 from the fuse cut current.
4. Circuit Explanation of Toner type detection block
This block detects whether Toner is brand-new or secondhand.
And also detect if the contact of the terminal is normal or abnormal (contact error).
(1) In case of Brand-new Toner
Since Fuse is not open, resistance between the fuse is approx. 4ohm.
So the voltage level of point A in the above circuit diagram is less than 1V.
As the result, both Q613 and Q614 are turned on.
(2) In case of secondhand Toner
When Fuse is open, resistance between the fuse is determined by the resistance of R99 (220ohm).
Since the resistance of R693 is 120ohm, the voltage level of point A in the above circuit diagram is approx. 3.5V.
Consequently Q614 is turned on and Q613 is turned off.
(3) In case of contact error of the terminal
Since both F99 and R99 are open condition, resistance between the fuse is infinite.
So the voltage level of point A in the above circuit diagram is approx. 5V.
Then both Q613 and Q614 are turned off.
According to the above transistor condition, the logic level of IC300_pinL24 and K26 are changed as below table.
Thus by checking these 2 signal levels, drum cartridge condition can be detected.
24V
CN80 CN508
1
1
5
5
F99 R99
Toner_Unit
TNR_CNTCT
(IC300_pinK26)
L
H
L
H
KX-MB2230JT/ KX-MB2270JT/ KX-MB2515JT/ KX-MB2545JT/ KX-MB2575JT/ DP-MB310JT
Fuse cut block
R691
Q609 R692
S5V S3.3V
D601
R694
Q613
S5V
A
Q614
Toner type detection block
Toner
TNR_LIFE
(IC300_pinL24)
L contact error
L Secondhand
H (Not used)
H Brand-new
77
Main Board
IC302
Q610
TNRFUSECUT
10
IC300
L 24
TNR_LIFE
K26
TNR _CNTCT
R696
status