Brother MFC-640CW - Manual (Page 168)

13 - 25 TROUBLESHOOTING AND ROUTINE MAINTENANCE
Cleaning the Paper Pick-up Roller
1
Unplug the machine from the AC power outlet and remove the
Jam Clear Cover.
2
Clean the Paper Pick-up Roller with isopropyl alcohol on a Q-tip
(cotton swab).
3
Re-insert the Jam Clear Cover.
4
Re-connect the power cord.