Digital BW, The Print

>The reason the heads clog is that the 1280 with OEM dye 
>inks uses smaller droplets than can be made with most 
>pigmented inks. Trying to force the larger droplets 
>through smaller holes causes the clogs.

I don't think it's the droplet or head nozzle size that is the problem.
Pigment inks work well in the R800 with much smaller droplet sizes.
Additionally, pigments work very well in the R220, which is made for dyes.
My understanding is that the nozzles size is about 25 microns, whereas the
pigment particle sizes are about 0.1 micron.

The 1280, however, has more trouble with high viscosity inks than the newer
printers.  High load pigment inks require a higher viscosity than the dye
inks.  I'd guess some of the 1280 problems might relate to getting high
viscosity inks through the screens in the 1280 head.  The 2000P appeared to
be basically a 1280.  They may have machined a totally different head for
it, but I doubt it.  I'd guess they either used a different screen or higher
voltages to the head.  The 2000P did have a slightly larger droplet size.

Paul
www.PaulRoark.com