HP5440 - "shadowed" text when printing in normal and high-qualitymodes

Hi! I have just bought a brand new hp 5440 deskjet printer. My
enthusiasm soon diminished when I found out that the printout quality is
bad in normal and qigh-quality modes, namely when I print tables with
text or italicized text. The thing is that the text printed has a grey
'shadow' even though the it is not formatted to have a shadow. What is
interesting, it does not happen when I print in colour or in the draft
mode or in the full bleed mode...

Has anyone had a similar problem with their hp5440 printer? Is it to do
with the software (drivers) or the hardware (the printer itself or the
black cartridge) or something else? Let me add that the problem persists
despite running the print-head alignment procedure or cleaning the
cartridges. Also, the same problem occurs under both WindowsXP and Linux
(Fedora Core 4).

Thank you for your help!

Regards,
Kamil