HP LaserJet Pro 400 Service Manual - Page 162

Print the Service Page 1. Touch the Setup button. 2. Open the Reports menu. 3. Touch the Service Page item. Clean the paper path To clean the paper path, process a cleaning page. Print the cleaning page 1. Touch the Setup button. 2. Open the Service menu. 3. Touch the Cleaning Page item. Print-quality troubleshooting tools Repetitive image defects If the product output has a consistent, repetitive defect, then use the table in this section to determine which part needs to be replaced based on the measured distance between the repetitions of the defect. NOTE: The following table replaces the graphical repetitive defect ruler. You can make your own ruler by using these measurements. For the most accurate results, use a metric ruler. Table 2-6 Repetitive image defects Distance between identical defects Component Notes 22 mm (0.87 in) 38 mm (1.5 in) 44.0 mm (1.73 in) 58 mm (2.3 in) 58 mm (2.3 in) 63 mm (2.5 in) 75 mm (2.9 in) 78 mm (3 in) Developer roller Primary charging roller Registration roller Fuser sleeve Transfer roller Preasure roller (one rotation) OPC drum ITB Replace the toner cartridge. Replace the toner cartridge. Clean the roller. If dirt still displays on the page, replace the registration unit. Process a cleaning page. If dirt still displays on the page, replace the fuser. Replace the secondary transfer feed unit. Process a cleaning page. If dirt still displays on the page, replace the fuser. Replace the toner cartridge. Calibrate the product. If dirt still displays on the page, replace the ITB unit. 136 Chapter 2 Solve problems ENWW