I built a product a long time ago using the HP ThinkJet printer inkjet cartridge. Now whilest that was a LONG time ago I had no trouble getting technical data for the cartridge from HP.

I could also comment that it seems reasonable to me that HP is quite anxious to sell inkjet cartridges. They and the other inkjet printer manufacturers make tons of money off the sales of cartridges. And for those that have some doubts about my opinion please consider why inkjet printers themselves are practically being given away these days. It is not unheard of that an inkjet printer can be had for prices comparible to 4 or 5 sets of inkjet cartridges for same said printer !!!
Michael Karas