If your originals have black streaks or appear dirty after scanning them through the feeder, clean the rollers of the feeder as described below.
If you are using the imageRUNNER ADVANCE 4035/4025, this mode can be set when the DADF-AG1 is attached. (See "DADF-AG1.")
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].
Make sure that you fan the sheets of paper well before placing them.
When cleaning is complete, try scanning again.