HP Color LaserJet Pro MFP M479dw
Troubleshooting. Image Quality. Repetitive defects ruler
When troubleshooting the source of some print image defects, one solution is to identify if it is a repetitive defect (does the print quality defect appear multiple times on the printed page?). If this is the case, use a ruler to measure occurrences of repetitive image defects to help solve image-quality problems.
Use a ruler to measure occurrences of repetitive image defects to help solve image-quality problems. Place the ruler next to the first occurrence of the defect on the page. Find the distance between identical defects and use the table below to identify the component that is causing the defect.
NOTE: Do not use solvents or oils to clean rollers. Instead, rub the roller with a lint-free cloth. If dirt is difficult to remove, rub the roller with a lint-free cloth that has been dampened with water.
|Distance between identical defects||Component||Notes|
|22.6 mm (0.89 in)||Developer roller||Appears in the form of dropouts.|
|23.6 mm (0.93 in)||Primary charging roller||Appears in the form of dropouts.|
|29.6 mm (1.17 in)||RS roller|
|35.0 mm (1.38 in)||Intermediate transfer belt (ITB) assist roller|
|50.0 mm (1.97 in)||Secondary transfer roller||Appears in the form of dropouts or dirt on the back of the page.|
|50.0 mm (1.97 in)||Large assist roller|
|57.0 mm (2.24 in)||Fuser rollers (3)||Appears in the form of dirt (front or back of page) or loose toner.|
|63.0 mm (2.48 in)||Photosensitive drum||Appears in the form of dirt or dropouts.|
|63.0 mm (2.48 in)||Tension roller|
|75.0 mm (2.95 in)||Scale|
|78.0 mm (3.07 in)||Cartridge station|
|78.0 mm (3.07 in)||Intermediate transfer belt (ITB) drive roller|
|712.0 mm (28.03 in)||Intermediate transfer belt (ITB) length|
NOTE: The primary charging roller, photosensitive drum, and developer roller cannot be cleaned. If any of these rollers are indicated, replace the toner cartridge.