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Users’ understanding of inks is very limited

Issue #1117 – Now, here’s an interesting one for a Friday afternoon. Pigment ink vs dye ink – do we need to know the difference and what difference does it make?

It has long been said that users, corporations and enterprises included, don’t know how much they spend on printing. The same can sometimes be said of users who frequently do not understand some of the basics of the technology they are using to be able to accurately define their needs and make intelligent purchases.

Where on earth is this going?

Quite simply, I have finally managed to track down an appropriate supplier of bulk pigment ink, at an appropriate price(!), for those inkjet desktop printers that are designed to use them. I just wanted black, partly because a number of printers use pigment black in conjunction with dye coloured inks and partly because it was a first purchase and I didn’t want to spend too much before being able to experiment and test the ink.

The seller was an eBay seller and the ink arrived today, so I thought I’d leave the customary feedback on eBay to encourage the seller.

Right under my feedback was a note from the previous buyer of this ink, saying “The ink does not work on most hp”. Please note here that the seller has inks for all manufacturers and the reference to Hewlett-Packard here is purely coincidental.

However, it is entirely relevant.

The comment refers to “most hp”. This buyer actually knew what he wanted but it occurred to me that, in his position, I wouldn’t have done because I thought that “most hp” inkjet printers use dye black ink and not pigment! I knew enought to know that what I wanted was pigment ink but not enough to know that, had I been buying for an HP inkjet printer, I would have got it wrong (but, at least it would have been wrong the right way round – read on to find out what I mean!).

So, I set about findiing out a bit more about it.

A great deal of my difficulty in finding an appropriate source for this ink has been down to the fact that a very great number of desktop inkjet printers do use dye inks and not pigment inks. Therefore, most third party compatible ink suppliers (cartridge or bottle) focus on dye inks and sell these even for printers that should be using pigment ink. What they certainly do not tell you is which printers should use pigment instead of dye black.

There are only two third party suppliers I have come across so far that do supply pigment black ink for a printer designed to use pigment black ink – those are Pelikan and Geha, both German. However, don’t get me started on that because testing of those brands, Geha in particular, has not shown them in the best of lights by any stretch of the imagination – poor cartridge design, very poor ink delivery, leading to very poor overall reliability and exorbitant Total Cost of Printing. The only factor in their favour is this use of pigment ink.

Until now, the pigment inks that I have been able to locate easily are sold for Large Format printers (for the graphics industry) and almost invariably for Epson models, specifying that the ink is designed for piezo inkjet print heads whereas I wanted ink that would be suitable for thermal inkjet print heads. Certainly, it is Epson that uses pigment inks (DuraBrite) in more desktop models than any other manufacturer. From Hewlett-Packard’s perspective, it is the Officejet Pro range that are primarily relevant to this discussion.

Now, I am not a chemist or an ink scientist and, as I have shown, I certainly do not know everything there is to know about inks. But, I know a man who does!

Pigment inks are considerably different to dye inks in their construction and chemistry and require different cartridge, print head and nozzle characteristics.

Cartridge spongeCartridge sponge
  • Pigment colorant particles are solids suspended in a carrier liquid, they do not dissolve, whereas a dye is a dissolved colorant. (If you take a look at the photos used as headers for the TCPglobal pages, this effect could only be achieved using pigment inks, dye inks would just have dispersed completely)
  • Mixing pigment and dye inks can cause clotting, which obviously would lead to clogging of the ink system in the printer.
  • Pigment inks are thicker than dye inks and will not flow properly through the sponge designed for use with a dye-based ink. This will lead to ink starvation at the print head, resulting in more cleaning cycles being required to maintain print quality, which it turn leads to more ink being consumed and therefore a much higher Total Cost of Printing.
  • Printers are designed specifically to place ink droplets on the paper in a manner that is appropriate to the ink type (to take advantage of the ink’s translucency or opacity). Using the wrong ink means that the ink is laid incorrectly for its chemistry.
  • Best photo printing is achieved by over-layering translucent inks, hence most inkjet photo printers use dye inks even if they use a pigment black ink for text (many printers contain both pigment and dye black inks – 5 cartridges).

In conclusion, it is possible to get away with use of dye ink in a pigment-based printer but:

  • It would be very unwise to try using pigment ink in a dye-based printer.
  • It would certainly be unwise to try refilling a dye ink cartridge with pigment ink.
  • It would be foolhardy to refill a dye ink cartridge with pigment ink without first putting the print head and ink system through a thorough purging and cleaning process.
  • It would be totally insane to refill a dye ink cartridge with pigment ink if the cartridge contains a sponge filler.

This is certainly one reason why just a little knowledge can be dangerous. Refilling cartridges is usually a very messy process anyway and not often a satisfactory solution. It should really only be tried for printers where the cartridge is easily refilled and is most satisfactory where the print head is separate from the ink tank.

Either way, it is absolutely essential to know what type of ink should be used in the specific printer in question – especially if it comes to considering buying pigment ink!