Copies in Seconds: Chester Carlson and the Birth of the Xerox Machine by David Owen
"A history of the photocopier offers a portrait of reserved physics graduate Chester Carlson, who invented the copier to ease his job as a patent clerk and who saw his marketing efforts daunted by numerous rejections, before the head of Xerox research recognized the machine's potential. "
My wife is a 2d grade teacher. She brought home her lumens ladybug that she used with her Promethean board in the classroom. However, the lag was terrible, her 2012 macbook pro just couldn't handle it. Our solution was to re-purpose an old ipad along with reflector teacher https://www.airsquirrels.com/reflector/teacher ($17.99). Yeah, just in case you're curious - my wife teaches for a SF Bay Area school district where I suppose they can afford lots of stuff except a refresh of eight year old laptops.
"A history of the photocopier offers a portrait of reserved physics graduate Chester Carlson, who invented the copier to ease his job as a patent clerk and who saw his marketing efforts daunted by numerous rejections, before the head of Xerox research recognized the machine's potential. "