Brother HL-L2310D Online User's Manual page 222

7. Remove the toner cartridge and drum unit assembly from the machine.
8. Push down the green lock lever and take the toner cartridge out of the drum unit.
9. Turn the drum unit as shown in the illustration. Make sure that the drum unit gear is on the left side.
10. Use the numbered markers next to the drum roller to find the mark on the drum. For example, a dot in column
2 on the check sheet means that there is a mark in drum region "2".
11. Turn the edge of the drum unit towards you while looking at the drum surface to find the mark.
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