Thanking all for the suggestions and replay.


The copy/print counter of the machine is around 400,000 pages for one machine and less than than for the second .

i have been using Katun toner for all these machines . it never gave any problem ( at least for me ).

charger roller is replaced and counter reset.

when swapping the developer crtb and drum crtg . developer and drum refresh and calibration is performed .


thanks guys