Patent attorney here. I used to do a lot of patents for the printer cartridges. The printer companies use the "give away the razor, make money on the razor bl

Patent attorney here. I used to do a lot of patents for the printer cartridges. The printer companies use the "give away the razor, make money on the razor blades" business model. The make very little on the printer, and make a killing on the cartridges. Thus, they spend a lot of effort trying to keep generic cartridges out of the market.