There are usually a few possible causes of a line on a laser print of
the nature you mention.
One is a scratch on the drum surface. This can be caused by a piece of
grit getting into the wrong place, from paper or elsewhere. Scratched
drums tend to hold toner in that location which is then transferred to
the paper and fused to it.
The other cause is if the drum wiper black has become damaged (again can
be caused by a piece of grit). In this case, the wiper black which is
supposed to clean excess untransferred toner to a waste chamber in the
cartridge, has a slight damage in it, and the toner is moved and
redeposited on the drum where this gap is. The wiper blade is usually
made of a silicone like rubber with a sharply cut edge. On rare
occasions a piece of dirt can lodge on this wiper and temporarily deform
the blade, again allowing toner to get under it and redeposited on the drum.
If the drum and wiper is accessible, you can sometime very gently run a
business card under the blade and gently slide it down the drum to clean
any grit or paper dust that might be deforming the blade. However, on
HP cartridges most of this stuff is internal and not easy to access
without taking the cartridge apart.
If the cartridge was purchased new and is an HP brand, they may allow
you to do an exchange, since they use recycled and reused parts even in
their newly boxed cartridges. Also, if it is from a refiller which
guarantees the quality of the refill, you may be able to get a
replacement. If you had the cartridge refilled yourself using your own
cartridge, you may have less options.
Art
