Archived from groups: comp.periphs.printers (
More info?)
"Michael Brown" <mtb@sgi.com> wrote in message
news:41922B0A.8E2CF74A@sgi.com...
>I had made a request to Canon as to the cause of the problem. Their
> first reply telling me to inspect the tank seating, printhead seating,
> and a do a few deep cleaning cycles - all of which I have done numerous
> times. If my problem still continued it likely was the printhead and I
> was given a number to the parts department.
>
> Below is my reply to Canon on what I found when I took the printer
> apart:
>
> ---------------------------------
>
> What I'd really like to know is how does the cross
> contamination occur? I've had the yellow tank contaminated three times
> now. In all cases I thoroughly rinsed all ink from the print head (I
> even removed the two screws holding the print head to the plastic
> carrier and rinsed the rubber washer between the printhead and the
> carrier). After doing this the printhead printed fine with fresh ink
> tanks. I don't see how any cross contamination can occur in the
> printhead - each color ink has a separate path to the print head.
>
> I've now disassembled the printer - with particular attention to the ink
> waste area. Printers are second to VCRs in the wonder of their
> mechanical design! I read one post on a newsgroup saying the hoses on
> the ink pump get brittle - mine were just fine - soft and supple. The
> pump appeared to work when I manually turned it - ink came out the tubes
> on the bottom side. Possibly the small rubber trays that raise up and
> sealed against the bottom of the printhead are not making their seal - I
> would have expected to find a pool of ink in the trays if that was the
> case - there was none. I re-assembled the printer with new tanks and
> its currently printing correctly.
>
> But... as before, if I let it set for a few hours, the yellow will print
> green. I'm sure if I let it set for days, the cyan would be leeched up
> into the yellow tank as it has done three times already. I did run the
> printer with the cover off and watched the printhead park. It appears
> the rubber trays are raised to seal the printhead when not in use. This
> is the only time there is an direct path between the cyan and yellow
> tanks. When the printer sits for a long period, can the inks possibly
> slowly drain from the tanks into the rubber trays sealing the bottom of
> the print head - filling the tray - and seeping back up into the other
> color tanks?
>
> Obviously with the thousands of the i850s/i860s Canon has sold, I know
> I'm not the only one to experience this.
>
> Can Canon offer an explanation? What specifically can cause this? I
> don't see how a new printhead can correct this - if so, what failed in
> the printhead? There just isn't much there to fail. I'd hate to spend
> $52 on a new printhead when I can buy an ip3000 for $80.
>
> ------------------------
>
While it would be great if they could, they can not possible answer such a
question accurately via phone or email.
having worked on more of these and other printers of similar design more
times than I can count, the most that can be offered without a visit to a
service center is 'possible' causes, which I and others have already
mentioned here in the newsgroup.
There are actually fine adjustments (and tools for doing so) in the areas
you disassambled. Could be that one of these is out of spec, could be a bad
printhead, could be bad ink or tanks. Often third party inks will refill
salvaged tanks and in doing so disturb the precision purge/weep hole at the
top of the tank. This can in fact cause the ink to excessively build up in
the waste/purge vavle area near the home position. So yes you therory there
is also possible.
At this point you have 3 options I can see.
1) Replace the printhead and hope that is the cause (most likely by the
way).
2) take it to an authorized service facility where they have the specs and
tools to properly diagnose and fix.
3) take advantage of the Canon loyalty program where you get a discount and
free next day shipping on a replacement printer (I have used this myself).
> Of couse I haven't told them I have been using generic ink tanks - that
> too easy of an out for them. (I've gone through one set of generics
> before my problems started) If my theory on ink pooling in the trays
> when the printhead is parked is correct, a thinner ink might be to
> blame.
>
Possible, or an ink with to rich an ethanol or glycol content may have
caused premature drying/shrinking of the 'O'-Rings in the printhead allowing
the inks to mix.
> Interestingly enough - I contacted the generic ink manufacturer
> (abcink.com) and explained the problem - they apologized for my having
> problems with their product and offered me a credit on my order...
More than most will do and one reason they can sell so cheap. They have no
liability should the printer fail as it is usually more costly to prove
their ink was the cause than to just replace the printer and they know that.