Geschke set up Adobe in 1982, giving the world the ubiquitous PDF software, among many other audio-visual innovations.
He made headlines 10 years later when he was kidnapped at gunpoint and held for ransom before being released unhurt after a four-day ordeal.
Geschke died in California on Friday.
Adobe CEO Shantanu Narayen said Geschke, widely known as Chuck, "sparked the desktop publishing revolution".