Like any other invention, the printing press came along and had an impact when the right conditions existed at the right time and place. In this case, that was Europe in the mid 1400's. Like many or most inventions, the printing press was not the result of just one man's ingenious insight into all the problems involved in creating the printing press. Rather, printing was a combination of several different inventions and innovations: block printing, rag paper, oil based ink, interchangeable metal type, and the squeeze press.
If one process started the chain reaction of events that led to the invention of the printing press, it was the rise of towns in Western Europe that sparked trade with the outside world all the way to China. That trade exposed Europeans to three things important for the invention of the printing press: rag paper, block printing, and, oddly enough, the Black Death.
For centuries the Chinese had been making rag paper, which was made from a pulp of water and discarded rags that was then pressed into sheets of paper. When the Arabs met the Chinese at the battle of the Talas River in 751 A.D., they carried off several prisoners skilled in making such