Panasonic UF-890 Service Manual page 191

Out of Toner Detection
Toner Sensor Output Signal
Status A
(Enough toner in the cartridge)
Max. - min. voltage is less than 1.0V
3V
Min. voltage is more than 1.4V
2V
1.4V
1V
0V
Toner Sensor output may change when the mixing blade passes above the Toner Sensor. Therefore
the output signal has a max. voltage and min. voltage during mixing blade rotation cycle (6 sec.).
E043
If the unit detects Status B 10 times during printing, the machine recognizes that the remaining toner is
low and the display shows "REPLACE TONER CARTRIDGE".
E041
After detecting E043 and the LBP Print Available Counter Value reaches "0", the unit logs E041
(OUT OF TONER).
E45
If the unit detects Status C when power is On, the unit logs E045 and displays "NO CARTRIDGE".
The unit will recover when detecting Status A after a new toner cartridge is installed.
Status B
(Remaining toner
is getting low)
Max. - min. voltage is less than 0.25V
Min. voltage is less than 1.4V
191
Mixing blade
rotating cycle
Max. - min. voltage is less than 0.08V
Min. voltage is less than 1.4V
Status C
(Almost no toner)