Setting the Fogging Prevention Mode
If you are using the machine in a low humidity environment, toner may be applied lightly to an area where supposed to be unprinted (white area). This problem may be solved if you set <Fogging Prevention Mode> to <On>.
1
Press 
(Settings/Registration) 
<Adjustment/Maintenance> <Adjust Image Quality> <Special Processing> <Fogging Prevention Mode>.
(Settings/Registration) <Adjustment/Maintenance> <Adjust Image Quality> <Special Processing> <Fogging Prevention Mode>.2
Select the mode, and press <OK>.
Set <Mode 1> or <Mode 2>. If <Mode 1> is set, the correction effects becomes weaker, and it becomes stronger if <Mode 2> is set. However, the toner density on the output may become lighter when <Mode 2> is set.