Michael 23 said:
Tony - thx for that great reply, makes perfect sense.
Ran test as described and sure enough it is streaked before it gets to
the fuser,
as if the toner simply isn't being 'told' to put anything there.
It is about a 1" wide stripe just to the right of center, totally
blank, no toner, with a slightly faded left edge and a clean right
edge... I assumed before posting something was stuck 'somewhere' but
could not find any way to get the box apart for a proper look! Would
make perfect sense if something was blocking laser - but how do I find
it?
OK so it is an imaging problem as I suspected. You have changed the toner and
that did not improve anything, also this printer does not have a corona wire so
that is not at fault.
First of all check the laser assembly, this is tricky to remove but you can do
a few simple things. We know that only a portion of the print is affected so
the laser has not failed since it is almost guaranteed to affect the whole page
if it fails. Open the top door and remove the toner cartridge, look inside and
down the front of the printer (it is hard to see this area), there is a sloping
steel panel and below that there is a near vertical panel with a slot in it.
Check that nothing is stuck in the slot, use a small mirror, if anything is
there it will be smaller than the missing portion of print because of the way
the laser works. Behind this slot is a shutter so all you will see is a piece
of steel (it may have a label on it), this shutter is opened when the cartridge
is inserted and the top door closed. If there is something behind the shutter
over the lens then it won't be visible. Hopefully whatever is causing the
problem is in front of the shutter and in view. You may be able to lift the
shutter up with a fine screwdriver but working in such a confined space is
tricky, and you must be careful not to scratch the lens behind the shutter. Do
all of this with the power cord removed of course.
An electronic failure is unlikely to produce these symptoms although an earlier
HP laserjet had a tendency to fail almost like this but the image became light
in the middle rather than disappearing completely.
The only other part that you should inspect carefully is the transfer roller,
when you lift the cartridge out you will see a roller that goes from right to
left immediately below the cartridge. This roller is soft and I have never seen
one fail this way but you could inspect it to see that nothing is wrapped
around it, do not touch it with your fingers or you will risk contaminating the
roller. It should be of consistent texture all the way along its surface. You
can rotate it using the small gear at one end.
For clarity the only parts that are involved with the imaging process are -
1. The cartridge - eliminated
2. The laser scanner
3. The transfer roller
4. High voltage power supply and other electronics - too expensive to repair
Unfortunately, as mentioned above, removing the laser scanner is tricky but if
you need to do that e-mail me and I will send you the instructions.
Tony
