(The following is from someone who also sells inkjet refill kits so this may not be an entirely unbiased writeup.)
(From: John Connolly (toner@idirect.com).)
There are at least 10 ingredients in inkjet ink, starting with triple distilled, de-ionized water, dye or pigment color of a known particle size, humectants such as glycol to minimize evaporation (and head clogging), surfactants to balance the surface tension and paper wetting, resins to get good paper adhesion, biocides and fungicides and buffering agents for the correct pH. These considerations ensure that properly reverse engineered inks not only work, but produce a print comparable to the OEM. For printers like Epson, with fixed permanent print heads in the printer, expensive repairs are also avoided.
To make matters worse HP has rigged their most popular black ink cartridges for the Deskjet 500 & 600 series to curb refilling, with air bladders, constantly changing maze/ venting assemblies at the bottom, and logic to change the signals to the micro-resistor jets on the 3rd or subsequent reinstallation of the cartridge. The color cartridges for these MUST be refilled before air locks occur, particularly in the yellow chamber.
Some people still manage to get an acceptable refilling success rate with these Deskjets, but we feel it is a bad introduction to refilling for the first time refiller. Deskjet series 700, 800 & 900 are better bets to refill.
But, the current Lexmark, Canon, Xerox and Epson cartridges are by far the easiest to refill.
Image Control's refill kits for the Canon 4000 series refill the BCI-21 black 40 times, or the BCI-21, 12 times EACH color.
More details on inkjet inks, a description of our refill kits which are larger than most offered, references and printer/cartridge tips are available at Image Control's Web Site.
