According to the caption that went with the photo (shown at the left), "His innovation—a rotary, web-fed, intaglio press—replaced earlier flat-plate presses. Rolls of paper were fed through curved, incised plates mounted on cylinders. It was much faster and more efficient than any previous press, as it printed, gummed, and perforated the stamps in one smooth operation."
Using the press, production speed increased from 85,000 stamps an hour to 250,000 an hour. An added benefit was that only four people were needed operate new press rather than the 20 or more were needed previously. Stickney presses produced U.S. stamps from 1914 until the last one was retired in 1962.
For more on the Stickney press, click here.