I was just recently talking to someone about this and what we realized was that printers are such a specific device the only companies making printer components are the ones making printers and they're probably not going to sell components to a startup clearly trying to compete with them (or at least not for a low price). And since printers and scanners use a lot of very specialised parts, you'd basically have to develop and manufacture them from scratch. High costs->low margins->low return->nobody wants to invest. Plus you'd get destroyed by the incumbents immediately because they'd just lower the prices for a year until you went bankrupt and then raise them again.