HL-4040CN FAQs & Troubleshooting HL-4040CN Not your product? Sort by: Updated Date Popularity 3 Results 1. 22/04/2016 How can I clean the inside of the printer? 2. 10/09/2014 How do I clean the Drum Unit? 3. 30/01/2014 How do I clean the corona wire on the drum unit? More FAQs Cleaning FAQs & Troubleshooting