MFC-7420 FAQs & Troubleshooting MFC-7420 Not your product? Sort by: Updated Date Popularity 3 Results 1. 11/17/2011 How do I clean the laser scanner window? 2. 12/03/2009 How do I clean the corona wire? 3. 04/27/2009 How do I clean the scanner glass? Cleaning FAQs & Troubleshooting