Dark Print Dirt on Back C4170-90959 Image Formation Troubleshooting 117 Possible Cause Action Poor contact between the drum grounding contact pin of the drive unit and the cartridge contact. Clean the contacts. Replace the contacts if the problem persists after cleaning. Poor contact between the primary bias contact on the Engine Controller Assembly and the cartridge contact Clean the contacts. Replace the contacts if the problem persists after cleaning. Defective Laser Scanner Replace the Laser Scanner Defective Engine Controller Assembly Replace the Engine Controller Assembly and the Intermediate PCB.
Possible Cause Action Particles accumulate over time inside printer (Tray Separation Roller, Feed Roller, Transfer Roller, Fuser, Toner Cartridge). 1. Print at least 10 pages to see if the problem goes away. 2. Print a cleaning page. See “To Start Engine Cleaning” (page 60). Identify and clean the dirty part according to the “Repetitive Defect Ruler” (page 127). If dirt cannot be removed, replace the dirty part. 3. Check for toner leaks. Paper does not meet printer specifications or is stored improperly. 1. Print a few more pages to see if the problem corrects itself. 2. Turn over the stack of paper in the tray. Also try rotating the paper 180 degrees. 3.
Check the paper (or other print media) type and quality. Replace the paper, and advise the customer to use the recommended paper and store it properly. See “Media Troubleshooting” (page 129). Dirt on an internal roller Use the “Repetitive Defect Ruler” (page 127) to determine the dirty roller. Clean or replace it. Dirty feed belt, feed guide, or fuser entrance guide Clean the dirty areas.