HP Pro 4300 C9H70UT C9H70UT#ABA manual Repetitive defects troubleshooting, Repetitive defect ruler

Repetitive defects troubleshooting

Defects on printer rollers can cause image defects to appear at regular intervals on the page. These defects appear at regular intervals that correspond to the circumference of the roller causing the defect. Measure the distance between defects that recur on a page. Use table 75 or the repetitive defect ruler (figure 207) to determine which roller is causing the defect. To resolve the problem, try cleaning the roller first. If the roller is still dirty after cleaning or if it is damaged, replace the indicated part.

CAUTION		Do not use solvents or oils to clean rollers. Instead, rub the roller with lint-free paper. If dirt is
		difficult to remove, rub the roller with lint-free paper dampened with water.
	Table 75. Repetitive defects
		Roller	Distance between defects	Replacement part
		Primary charging roller	37.7 mm (1.5 inches)	print cartridge
		Developer roller*	62.8 mm (2.5 inches)	print cartridge
		Fuser	75.0 mm (2.95 inches; HP LaserJet 4200)	Fuser
			94.0 mm (3.75 inches; HP LaserJet 4300)
		Photosensitive drum	94.2 mm (3.75 inches)	print cartridge
		*The developer roller circumference is 62.8 mm (2.5 inches). This defect will most likely repeat at intervals
		of 54.0 mm (2.125 inches) because of the way it is geared.
Note		Defects on the tray pickup rollers or the tray 1 pickup roller do not cause a repetitive defect.
		Defects on these rollers cause a defect to appear only on the leading edge of the image.

First occurrence of the defect

*Note: The developer roller circumference is

62.83mm (2.5 inches). This defect will most

likely repeat at

intervals of 54.0 mm

(2.15 inches) because of the way it is geared.

37.7mm (1.5 inches) primary charging roller

54.0mm (2.125 inches) developer roller (see note)*

62.8mm (2.5 inches) developer roller (see note)*

75.0mm (2.95 inches) fuser (HP LaserJet 4200)

94.0 mm (3.75 inches) fuser (HP LaserJet 4300)

94.2 mm (3.75 inches) photosensitive drum

Figure 207. Repetitive defect ruler

Q2431-90912 Chapter 7 Troubleshooting 325