Print on demand brief history, because the offset printing cost is high if you want to print just a few copies. There is a solution for this with print on demand. For amateur publisher, print on demand technology is really help them to build their image with customers, because if they are go to offset printing company to print their books with quantity less than minimum they have to pay it expensive. Because the offset printing technology is real cheap if you print more than minimum. This is a dilemma for publisher. If they print it with minimum order requirements for their books, they will spend much money and get a lot of books that they should sell. But with big quantity of books for publisher that "unknown" by people is hard to sell.
With print on demand publishers doesn't have to worry about it, they can print their books after order received by them. For example, Josse is a amateur book writer, and he want to sell his book. So he make a website about his book. After someone order it, and his customers paid, Josse go to print on demand publishers and print his book one copies with cheap price. After that he send it with courier to his customers. Josse happy, his customers happy. Thanks to print on demand publishers who makes them happy.
Print on demand like digital print but not same. With more features and cheap printing cost not like digital print who need expensive toner, print on demand is publishers favorite. Because it fast and good quality.