Repetitive Defects Ruler - HP LaserJet 4L and 4P
The repetitive defects ruler can help pinpoint the cause of repeating defects. Measurement is taken from the first occurrence of the defect to the second occurrence.
Special note: Bad toner cartridges are the most frequent cause of print defects. As you examine the defect ruler, please note that the following components are internal to the toner cartridge: Primary Charging Roller, Developing cylinder or roller, Toner cartridge photosensitive drum. If these parts are identified as the problem, you will need to replace the toner cartridge.
Ruler for HP LaserJet 4L and 4P