When were 1 hour photos invented?

In 1981.

If you want to get fussy about it, 1 hour photos were invented when Kodak introduced the C-41 film process, enabling a lab to develop a roll of film and dry it in approximately 30 minutes. The reason 1-hour processing didn't come about until 1981 is the processing machinery was hard to use, large and expensive, requiring skilled operators, large amounts of floor space and a big investment - so people would buy the machines, put them in centralized labs, and hire drivers to go around to different stores picking film up from drop boxes and kiOSks, and delivering finished prints. A French company called Kis, who made photo booths, invented a machine that was small and inexpensive enough to install in a store so people could have their pictures processed while they waited.