Cause
Mottled effect is caused by the following possible causes:
Low image transferring due to toner deterioration
Too high or too low of toner charge
End of unit life (ITB unit, PTR unit or developer).
Malfunction of image transfer roller or PTR unit
This is likely to occur if:
Using paper with low smoothness
Printing an image with low coverage continuously
Printing in the low humidity condition
Printing in the high humidity condition
