Complex sentence: It was almost 18 years before a fully automated process was developed, the key breakthrough being use of a drum coated with selenium instead of a flat plate, resulting in the first commercial automatic copier, released by Haloid/Xerox in 1960.
Split into simpler sentences: It was almost 18 years before a fully automated process was developed, the key breakthrough being use of a drum coated with selenium instead of a flat plate. This resulted in the first commercial automatic copier, released by Haloid/Xerox in 1960.