Digital BW, The Print

Dan,


> It happened again...
> 
> I've been away from the printer for five days, did a print, and it had a
> strong magenta cast. I took out all the cartridges, gave them a good
> shake and put them back in. Problem solved.
> 
> Am I the only one experiencing this?
> 
> This is with color prints using the MIS Archival 7600 inkset. I haven't
> had the same problem with the UT7 inks, but I guess the effect would be
> much harder to notice in a BW only inkset anyway.
> 

Actually, it showed up with the original UT B&W formulas, but I
re-formulated them at the end of 2004 to get rid of the magenta -- the
problem.  That pigment tends to settle.  I speculate that the supplier made
them larger to try and offset their relatively weak lightfastness.  But, as
the particle size increases, the surface area to mass (weight) decreases.
So, the particles will tend to settle faster, all else being equal.  The
original 7600 UC clone inkset magenta had a higher viscosity in an attempt
to offset this.  However, this could not be maintained when the magenta was
mixed with the other inks in the B&W inkset (the other relevant inks have
essentially the same viscosity base), and the higher viscosity was not
compatible with the 1280 and other dye-based desktop printers -- thus the GP
inkset.

On most desktop printers the problem was also alleviated by regular use of
the printer.  The head agitates the ink carts.  So, the B&W UT problem
showed up most on printers like my 7500 with the UT1 inkset after I had not
printed for a while.

If you're using the 7600 inkset in a 2100, I'm a bit surprised that it shows
up.  But, as you've found, agitation takes care of it.  It does make me
wonder if the inkset you have is the 7600 clone or the GP inkset.

Paul
www.PaulRoark.com