HP LASERJET P3005 - HP LaserJet 4250;4350 Series: Black Bar Print Quality Issue

HP LaserJet 4250/4350 series printer—First page prints
with a black bar across the top
We have recently discovered a print quality
issue with the HP LaserJet 4250/4350 series
printer. On the first page printed in the
morning (or after the printer comes out of
PowerSave mode) a black bar prints across the
entire width of the top of the paper. After
printing the first page the bar no longer
appears.
Sample page with black bar across the top
Solution 1
Be sure to unplug the printer before you begin
the following procedure:
In most cases, you can correct the print quality
defect by cleaning the developer and charge
roller contacts with canned air. Push the spring
contacts to ensure they flex properly and can
spring forward to contact the toner cartridge.
Contact locations
Solution 2
If cleaning the developer and charge roller
contacts does not solve the problem, you will
need to remove the high-voltage power supply
and re-seat the power supply after adjusting
the developer bias contact.
The photo below shows the printer’s interior
(looking in from the rear of the printer) with the
high-voltage power supply removed. The
springs that are hanging down in the photo
are the high-voltage contacts, providing a
connection between the toner cartridge and
the high-voltage power supply. We suspect
that the developer contact (inside the toner
cartridge) and the developer voltage contact
on the high-voltage power supply are not
making adequate contact.
Using needle-nose pliers, bend the developer
high-voltage contact down at the elbow 1-2
mm to ensure a better connection with the
power supply contact. Re-install the high
voltage power supply.
Char
g
e roller
contact
Drum
g
round
contact
Bend the contact down to ensure a connection
Developer
roller contact
HP Monochrome LaserJet printer updates 7