> Not one teacher could differentiate type written papers, from dot matrix.
It just strains credulity. Daisy wheel, sure, but not in the history of dot matrix printers, from start to finish, were they comparable to typewritten output.
It was very slow in the highest quality setting, but most people couldn't tell it apart from much more expensive solutions. It also had an astounding equation editor which made it great for STEM work.
Maybe I'm a printer nerd, but I could generally tell the printer manufacturer from its output in the time they were popular.
Not to mention that back then, I don't think any consumer-grade dot matrix used single sheet paper like a typewriter would. The tractor punched-hole bars on the side after removal would give it away; even that fancy super-perforated stuff.