An interesting but now old WSJ article on HP and its ink...

[korny]

Old timers in this forum have, Im sure, seen this old Wall Street article I point out below.
I simply found it interesting.

I stumbled on it because someone in the forum had mentioned the so called "egg yolk test" which, if I understand correctly, is a simple indicator to see if an ink is of high quality or not. The test checks to see if a black pigment droplet will separate in a pool of yellow dye ink or stay put (not dilute). There is some serious chemistry involved in pulling that off, I take it.

....just be aware that this article is close to five years old now..

"HP Chemists Hunt Violators Of Ink Patents"

http://people.ischool.berkeley.edu/...ock-in/Articles/ink-jet-patent-violators.html

MY SUMMARY -- 2006 WSJ report:

HP (had) a 50% marketshare
4000+ patents on file on ink
80% of HPs $5.6B profit is on inks and toner
Lawsuits against anyone copying the ink, too well
HP has intensive daily in-house testing of ink copies they find..
The simple egg-yolk test indicates high quality ink, (perhaps patent infringing)

 

[qwertydude]

An informal egg yolk test is simply to test if a black ink is pigment or dye. Color ink is easy to differentiate as pigment inks are lighter and milky in appearance. Black it's difficult to tell. But the egg yolk test makes it readily apparent. HP also does the test but has different test parameters likely to ensure that the black won't smudge onto color areas like when printing highlighted black text.

 

[nche11]

Ink patents are pretty useless in reality. I once heard a PHD in chemistry saying you just need to make a slight change, say to the PH, it makes an imitation free from patent infringement issues. Well, that may be an over statement. But it is true that it is easy to avoid patent challenges by making very small changes to the formulation of ink to avoid patent issues. HP may won inspiration from its huge number of ink patents but the patents never protect them from the competitions from the imitation.

 

[ghwellsjr]

An informal egg yolk test is simply to test if a black ink is pigment or dye. Color ink is easy to differentiate as pigment inks are lighter and milky in appearance. Black it's difficult to tell. But the egg yolk test makes it readily apparent. HP also does the test but has different test parameters likely to ensure that the black won't smudge onto color areas like when printing highlighted black text.

It's very easy to tell if a given ink is 100% pigment or 100% dye. If you print a nozzle check on plain paper, the pigment ink should not run (after it dries) when you dribble water across it. And if you print a nozzle check on glossy photo paper, the pigment ink will wipe right off the surface, whereas dye will not.

 

[nche11]

You can print on glossy photo paper with pigment based inks using an Epson printer. The ink will not be wiped off the surface. I am very certain about this. I seem to remember printing with PGI-5 on glossy photo paper too. The ink stayed fine on the paper after it dried.

 

[ghwellsjr]

You can print on glossy photo paper with pigment based inks using an Epson printer. The ink will not be wiped off the surface. I am very certain about this. I seem to remember printing with PGI-5 on glossy photo paper too. The ink stayed fine on the paper after it dried.

You're right if you use Epson's DURABrite paper designed for both pigment and dye inks. I should have stated to use a glossy photo paper designed exclusively for dye ink. Thanks for pointing this out.