MFC-3420C FAQs & Troubleshooting MFC-3420C Not your product? Sort by: Updated Date Popularity 2 Results 1. 16/11/2016 My machine does regular cleaning cycles in the night. How can I correct this? 2. 24/08/2006 How do I clean the Scanner to improve the copy or fax quality? Cleaning FAQs & Troubleshooting