The real answer for disrupting the printer industry is making and selling “cartridge refiller devices”. You sell the ink super cheap (hell, you could give it away for free, it’s that cheap). Your margin is on the refiller devices: the fact that printer companies have made hundreds of different cartridges with a myriad of anti-tamper mechanisms means you offer dozens of different devices, and whenever the big bad printer companies make their cartridges more hostile, your scrappy little company diligently reverse-engineers them and offers a new refiller device, and the customer is happy to buy it because he’s sticking it to the printer man.