Digital BW, The Print

Paul Roark wrote:
>>Don't leave the "Glop" sat in your printer for along period unused, 
>>some types can react and cause the ink to dry out and solidify in 
>>the cartridge particularly if it is acrylic or urethane based. 
> 
> 
> Thanks for the warning.  I had a similar feeling and pulled it out as soon
> as the experiment was done.  I use a C86 for testing.  It's a lot cheaper to
> wreck one of these than the alternatives.
> 
> Glop is, of course, meant to be used in a printer, at least by itself.  I've
> tried to inquire about clogging, but have found no evidence yet that it
> clogs more than other inks.  This is an issue to keep an eye on, however.

Isn't the glop as used in the Epson R800 and its MIS clone not
basically the normal ink carrier without pigment but more 
resin added ?  PVA as the
only resin component in it that will act as a very fragile 
coating that can't be compared to water bases acrylic 
dispersions and polyurethane coatings like Hydrocote's 
Polyshield. Especially the last is something you wouldn't like 
to use in inkjets as it can hardly be resolved after it dries, 
depends on its hydrolyse grade of course.

>>We did a 3year test on several versions of this type of combination.
> 
> 
> Is it just the combination with other inks that is the problem, or does glop
> by its nature tend to solidify?  
> 
> Frankly, the bulk glop looks most like the UT base.  When it is printed by
> itself, it does have a bit of density to it.  So, it's clearly not just
> base.  I think I've read the Epson version is an acrylic suspension.
> Water-borne acrylic sprays, like aerosols, seem to have a bad reputation for
> clogging those nozzles.

What Epson writes is "the same high density resin as used in 
the coating of the pigment particles". Sounds almost like a 
description of polyethylene or polypropylene instead of 
acrylics. But I guess it is to indicate it isn't a PVA but the 
last has different grades too. A modern copolymere is more likely.

> A paint technician once described water-borne acrylics as being like gooey
> little golf balls suspended in water.  I have assumed that the acrylic that
> Epson uses is relatively solid, but, on the other hand, it is used around
> their pigments to help hold them onto the paper.  

The acrylic coating of the pigment (pellets) has more than
just a function in bonding. It delivers a better protection of
the pigment itself and enhances the gloss quality of the ink.
I did read somewhere that their particle shape and consistency 
suited the piezo head. Bloodcells alike so to speak. 
Thixotropy at particle level.




Mars-Staedtler announced a waterbased inkjet ink that gives a 
a bond with a wide variety of substrates for outdoor use, the 
base could be an interesting alternative for glop if there are 
no other limitations in its use.

Ernst