Panasonic UF-490 Service Manual page 136

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 (4.75 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 "TONER LOW".
E041
After detecting E043 and the LBP Print Available Counter Value reaches "0" (after 100 pages are
printed), the unit logs E041 (OUT OF TONER).
Status A'
(Enough toner in the cartridge)
Max. - min. voltage is more than 1.2V
Min. voltage is Less than 1.4V
Mixing blade
rotating cycle
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Status B
(Remaining toner is getting low)
Max. - min. voltage is less than 0.5V
Min. voltage is less than 1.4V