HP Color LaserJet Pro MFP M177fw

If the product output has a consistent, repetitive defect, then use the table in this section to determine which part needs to be cleaned or replaced based on the measured distance between the repetitions of the defect.

NOTE: Spots can be dark or white (dropouts); bands can be all shapes and sizes.

Component	Distance between defects (mm)	Type of defects
Developing roller *1	About 22	Dropouts Dark, sharp bands
Primary charging roller *1	About 26	Dropouts
RS roller	About 29	Dropouts
Secondary transfer roller	About 47	Dropouts Dirt on the back of page
Fuser film	About 58	Dropouts Dirt on page Loose toner
Pressure roller	About 63	Dirt on page Dirt on the back of page Loose toner
ITB drive roller	About 76	Spots
Photosensitive drum *1	About 95	Dropouts Dirt on page

*1 - The primary charging roller, photosensitive drum, and developing drum cannot be cleaned. If these rollers cause a repetitive defect, replace the corresponding cartridge, either the imaging-drum cartridge or the developing cartridge.