Brother HL-L3230CDW Wireless Compact Printer - Manual (Page 284)

8. Reinsert the belt unit into the machine.
NOTE
To avoid print quality problems, DO NOT touch the shaded parts shown in the illustrations.
9. Reinsert each toner cartridge and drum unit assembly into the machine. Make sure that you match the toner
cartridge color to the same color label on the machine for all four toner cartridge and drum unit assemblies.
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