Samsung SCX-4521FG - Manual (Page 57)

Maintenance
8.6
Replacing the ADF Rubber Pad
You can purchase an ADF rubber pad from your Samsung
dealer or the retailer where you bought your machine.
1
Open the ADF cover.
2
Remove the ADF rubber pad from the ADF, as shown.
3
Insert a new ADF rubber pad into place.
4
Close the ADF cover.