Brother DR-1090 Help Manual page 8

7. After pulling the pull-arm (2) on the left side of the machine down,
close the scanner cover.
Reset the drum counter
1. Press Menu.
2. Press the Up or Down arrow key to choose Machine Info.. Press
OK.
3. Press the Up or Down arrow key to choose Reset Drum. Press OK
for 3 seconds.
4. Press the Up arrow key to reset the drum unit counter.
5. Press Stop/Exit.