Digital BW, The Print

Maybe a dumb question... I've been a bad boy and left my Eboni-6 (actually just the MK and Y dilution) sitting in its carts and bottles for about 9 months without agitation (haven't been printing).  I know there are settling issues with this ink set.  Can I just agitate these things thoroughly and then let them sit for the bubbles to disappear and be back in business?  The bottles say use before 12/10 so I'm guessing this should be OK.  Any thoughts?

Thanks,

Ken

"kwalsh74" <kwalsh74@...> wrote:
>
> .. I've ... left my Eboni-6 (actually just the MK and Y 
> dilution) sitting in its carts and bottles for about 9 months 
> without agitation (haven't been printing).  I know there are 
> settling issues with this ink set.

Actually there are settling issues with all pigmented inksets, they're just worse with the 6% - 30% dilutions of Eboni/Carbon-6.

That said, the Y (2%) and K are relatively stable.  

Actually, I suspect the K just does not show its settlement due to the very non-linear nature of the density/load relationship in an inkset with this high a load; it can thin out significantly at the top and still print with a good dmax.  I might add here that the worst density change from settling I've seen in a printer was the Epson MK in the 7800 I bought used.  It had been on a counter such that the (intentially?) flimsy base was not allowing agitation when the printer was being used, and the printer was not used that often anyway.

For perspective, the 2% Eboni settles more than Epson LLK, but Epson LLK settles the same amount more than MIS PK or LK when diluted for making a warmer version of a 100% carbon inkset.  The more neutral carbon may be such "largely" due to the larger size of the particles; the size of the particles is a major factor in how quickly they settle.  MIS PK/LK is warmer than Epson's versions and is more stable -- in fact, it makes a very stable, warm, 100% carbon inkset when diluted with the C6 base (matte only with the C6 base; glossy if glop is used for dilution). 


>  Can I just agitate these things thoroughly and then let them
> sit for the bubbles to disappear and be back in business? 

Yes, I think you'll be fine.

Note that the settling is a compression of the distance between the particles.  It appears NOT to be "flocculation" (the formal term for the clumping or "agglomeration" usually referred to on these lists).  The flocculation (sound vaguely obscene) is the real problem and what might happen to out of date pigment as the electronic charges on the surface of the particles dissipates.  The coatings or edge treatments of these particles is what keeps them separated.  These electrostatic coatings appear to slowly oxidize or otherwise deteriorate, and when that happens we do have problems.   

> The bottles say use before 12/10 so I'm guessing this should be OK.  

You should be OK.

Paul
www.PaulRoark.com

Wow, Paul.  I have always known there is great danger in asking a simple question of a knowledgeable person.  If you bring up Hildebrand parameters I might have graduate school flashbacks and collapse on the floor :).

No, seriously, thanks for the extremely detailed and informative answer.  Now that you mention the stability of the Y dilution it rings a bell of probably reading something you wrote a long time ago about your MK-Y approach on the 1.5 pL printers.  I think I recall the Y dilution also proved to be less warm than the other "middle" dilutions?

And yes, the root of my question was am I going to have a flocculation problem or just compression but I didn't know how to express that properly.  I guess, if my extremely limited understanding of surface energy chemistry is at all the right frame of reference, I wouldn't expect agitation either frequently or after the fact to be of any help in flocculation.

As always, thanks for your excellent contributions!

Ken

Paul, what happens to out of date ink?  If it flocculates, will agitation
"unflocculate" it?   I've also heard that algae growth may develop.  To
prevent that, I've put a 1 inch piece of copper wire in the storage bottles.

 

Bob



[Non-text portions of this message have been removed]

"Bob Marsolais" <bob@...> wrote:
>
> Paul, what happens to out of date ink?  If it flocculates, 
> will agitation "unflocculate" it?   

I'm not sure what all happens to the old pigments, but I do see more sedimentation in old bottles that I assume is flocculated pigment.  I doubt you can effectively break up these particles.  From what I can tell the electrostatic repulsion of the particles simply fails with age.

> I've also heard that algae growth may develop.  

Yes, I've heard of this also but never actually seen it.  I've been told stories of CISs in sunny areas getting algae in the tubes.  MIS once recommended keeping CIS systems in the dark as a simple solution.

> To prevent that, I've put a 1 inch piece of copper wire in 
> the storage bottles.

I've speculated that such might work.  The only test I did to some algae polluted water did indicate the growth of the algae was significantly slowed by putting in a copper wire.  I have not tested ink with "copperized" water.  At some point the copper ions might get to the point where the oxidized copper causes some color or other effects on the paper.  It does sound like an interesting approach to test, however.

Paul
www.PaulRoark.com