If your originals have black streaks or appear dirty after scanning them through the feeder, perform an automatic feeder cleaning for the rollers of the feeder.
1.
Press 
(Settings/Registration).
(Settings/Registration).2.
Press [Adjustment/Maintenance] → [Maintenance] → [Clean Feeder].
3.
Place 10 sheets of blank paper into the feeder → press [Start].
It takes approximately 15 seconds to clean the feeder.
Use normal LTR size paper.
When cleaning is complete, try scanning again.