Apparently, the printer keeps track of the number of pages, regardless of how much toner is actually used, so sometimes user needs to manually Reset Toner low logic as follows:
1. Open the front cover that gives you access to the toners.
2. Press and hold “Secure Print” and “Cancel” at the same time. You will see “K-TNR-STD” display on the screen.
3. Using the “+” and “-” buttons select the toner you want to reset.
4. Press the “Ok” button.
5. It will display “Ok?” and hit the “Ok” button again to reset the toner.
6. Close the lid.
When you replace the drum unit with a new one, you need to reset the drum counter by completing the following steps:
1. Turn the printer power switch back on.
2. Press the + or – button to choose “Machine Info”.
3. Press OK to proceed to the next menu level, and then press the + or – button to choose “Reset Parts Life”.
4. Press OK, and then press the + button to choose “Belt Unit”.
5. Press OK two times.