[pifm_guy]

Typically one can fix that by adjusting the transfer drum voltage, normally found in the service section of the menu.

You might also need to adjust the fuser temperature for non-oem toners

[nebula8804]

Lets put aside the fact that you wouldn't know the correct values for whatever garbage generic toner the refill company gave you. How are you going to deal with the fact that the printer already has particles of the old toner in the system and now you are introducing contamination with a set of different particles from the new cartridge/refill?