Digital BW, The Print

Nij,

Well now we are completely out of order unless Yahoo does us a favor 
and posts this one before my last post!

Actually I would be amazed if all the inks were the same even if they 
were trying to do that! Making a good pigment dispersion is not easy. 
Having someone on board at ConeTech who knows this stuff is really 
important and demonstrates an acknowledgement of the issues and a 
commitment to solving them.

My thought here was that bubbles are dependent upon surface tension 
and if you increased the surfactant that might help the reduce 
tendency of the bubbles to form. A way to change the viscosity 
without changing the pigment loading and causing the problems you 
mention. Without knowing a great deal more about the formulation and 
manufacturing process I could not say for sure. More of a wish that 
the solution is something simple like that, rather than something 
that would require a pigment change which would be a very big deal. 
Any change would have to be approached with caution because any 
change is going to involve a trade off. If you push in one direction, 
something else is going to shift somewhere else.

I do have an expectation that the inks would be designed to behave 
well in the printers they are being marketed for. Obviously no one 
would intentionally design ink that was going to be prone 
to "clogging". What is tough for a small outfit is that they are 
likely to buy one or two examples of a given printer model and not 
20. They then miss the fact that the ink is great in let's say 90% of 
the printers but causes problems and bad press in the remaining 10%.

(I want to stop and define a "clog" as a non-printing nozzle that 
does not clear within 4 nozzle cleaning cycles forcing an overnight 
wait. Occasional blockages with Epson inks are not uncommon, not hard 
to correct and non-Epson inks should not be held to a higher 
standard.)

This is a shot in the dark and maybe you can ask Jon if I am correct, 
but my impression is that Piezo grew out of Jon's work to print 
platinum like prints on the Iris. It may be that this ink transferred 
well to the 3000 but as they expanded into the other models the 
clogging issue came as a surprise. If that is how it occurred then 
they would be in a real jam because fixing the "clogging" issue for 
the minority of printers could lead to other problems. The other 
tough problem is that when ink is ordered from the manufacturer there 
is probably a minimum size and a little bit of ink goes a very long 
ways. So they don't get a lot of chances to tweak the product in 
process, which would be risky in any case. So the best thing to do 
might be to just gut it out. This is all speculation mind you.

That's why I am very interested in the "selenium" inks because they 
will have had a chance to not only come up with another tone but will 
have a chance to address the "clogging" issues at a formula level in 
light of past experience. 

I think the real economic pressure might come from the MIS Full 
Spectrum inks and not the MIS Variable Mix. If the MIS continues to 
be "clog" free, at the lower price and if no other problems surface, 
I would expect a fair number of people to buy Piezo and then switch 
to the FS inks. However, MIS has missed the boat here by not selling 
the FS in a hex set and the quad printers are vanishing fast. I would 
think this would put pressure on ConeTech to reformulate but it would 
make sense to do this after the "selenium" is in place.

A lot of random thoughts. It will be interesting to see how it plays 
out.

Martin




--- In DigitalBlackandWhiteThePrint@y..., "Nij" <nigel@m...> wrote:
> Martin,
> 
> You know I'm not an ink chemist by now - I don't even know what a 
surfactant
> is (tho' I understand that my washing powder has non-ionic ones - 
cool!  ;)
> 
> But it surprises me that you seem to expect that 'all inks are the 
same' -
> you know I don't mean it quite like that, and I know you don't mean 
it quite
> like that - but aren't we talking a balancing act here? A balance 
between
> colour/tone, amount of pigment or dye on the page without first 
soaking the
> page in thinner or carrier solution or whatever it's called.
> 
> e.g. One way to solve the problem might be to thin the inks... but 
the cost
> of this might be to have a 5 minute pause between print-head passes 
for some
> thinner to off-gas - IF you wanted to achieve the same level of 
colourant on
> the page without ruffling. Or perhaps it has no effect on that, but 
reduced
> ink shelf-life... or whatever.
> 
> This is clearly an area that you and Terry in particular know much 
more than
> I on the technical front - but when I read your recent comments it 
_sounds_
> to me like you think that all these problems can be resolved without
> undesireable consequences that you might find equally objectionable!
> 
> Nij
> 
> 
> 
> > -----Original Message-----
> > From: Martin Wesley [mailto:mwesley250@e...]
> >
> >
> > Nij,
> >
> > I agree with you that the "clogs" that we all talk about are very
> > likely air bubbles for the most part. (probably not the severe 
Hayes
> > issue though it could be related.) This is why the "wait and let 
it
> > settle" process works so well. Which does lead me to feel that it 
is
> > a formulation issue. If there was more surfactant in the formula
> > perhaps this would not be such a common problem.
> >
> > I was very happy to hear Jon has gotten an ink chemist on board.
> > Hopefully the issues are easy ones and can be resolved quickly.
> >
> > Martin
> >