Digital BW, The Print

Bob,

>Paul, I noticed what appears to be some magenta pigment 
>settling out in the yellow chamber of my 1280 color cartridge. 
>Is magenta pigment used in the UT2 yellow position?

The original UT2 yellow-position sepia ink did use magenta, and it would,
indeed, settle.  To eliminate that we started to use the R800 red, which
appeared to be better.  However, I'm still suspicious that in the blended
ink it could settle.

Do you use carts or a CFS?  Usually in carts that are installed the printing
agitates the carts continuously, such that settling is not a problem.  Where
I usually see the problem is in the lines of large format printers and CFSs,
and in bottles or carts that are left on the shelf un-agitated for a long
time.  All pigments eventually settle.  They are all heavier than the base
they are suspended in.

>Do you how long UT2's self life is or how long before it the 
>pigments start to settle?

MIS puts a 2 year date on the bottles now.  If they are left un-agitated,
they'll show settlement way before then.  If regularly agitated, I'd guess
the life is longer than 2 years.

> I make it a point to shake the bottles every now and 
>then, but not the carts as I'm afraid of getting air in the chambers. 
>Any thoughts about this?

I just installed some carts that had sat still for a long time.  I shook
them, and they've been fine.  These carts have some sponge in them, and I'd
wait a while after shaking to use the cart.

Paul
www.PaulRoark.com