PRINTING PRESSES. The first printing presses were a development of the cheese or cider press common in all large mediaval house holds, and needed little change to adapt them to the uses of typography.
Gutenberg's press, upon which he printed his 'Bible' of 36 lines (1450?), his of 42 lines (1455?), and the of Indul gence' of 1454, 1455, 1461. consisted of two timbers with connecting crosspieces at top and bottom, and with two intermediate cross timbers. The lower one was the support of the form of type. Through the upper passed a large wooden screw, the lower end of which rested on the centre of a wooden platen. After the form of type was fastened to its bed it was inked by hand inking-balls made of wool covered with soft leather. The sheet of paper, previously dampened, was then laid carefully upon the type, and the bed pushed to its place. A wooden lever was thrust into its socket and the platen screwed down, held for a moment and then raised. The bed was drawn out and the printed sheet removed and hung up to dry. For 150 years this simple but effective form of the printing press continued in use, and the books thus printed by Faust and Schaffer at Main; Jenson and the Aldi at Venice, Caxton at Westminster, Plantin at Antwerp, the Elze virs at Leyden and at Amsterdam, and Bade and the Estiennes at Paris have brought their makers the highest fame.
First The first recorded improvements were those of William Janson Blacuw, of Amsterdam, about 1620. He passed the spindle of the screw through a wooden block, which was guided in the wooden frame, and from it hung the platen. He also invented a device for rolling the bed in and out under the platen, and improved the hand lever for turning the screw. This press was widely used on the Continent, and in England and America, and on such a one Benjamin Franklin worked in London in 1725. One of these, that from the Watt printing house, is now preserved in the Patent Office in Washington. For nearly two centuries this sufficed for books of small editions and for the little-circulated small news papers and gazettes of the 17th and 18th cen turies. The Earl of Stanhope in 1798 made
a press with a cast iron frame and greater leverage that had some use in England. George Clymer, of Philadelphia. in 1816 substituted a combination of levers for the screws, and called his invention the Colum bian press. He carried it to England and there in 1822 Peter Smith devised a toggle-joint, sim ple and effective, that replaced the screw and levers.
The final development of the hand press came in 1827, when Samuel Rust, of New York, perfected the Washington press. The iron frame was lightened and strengthened, the toggle motion was, improved and a screw top regulated the pressure. With this improved hand press came the substitution of composition inking rollers for the leather covered ink-balls previously employed. The bed was made to slides in and out on a track by turning a crank connected with two endless bands., A bent lever working in a toggle-joint forced the platen down and coiled springs raised it. To the end of the bed was attached the tympan, a wooden or steel frame over which a cloth was tightly stretched and carrying the blanket to modify the force of the impression. When the bid was run out this was raised to an ob tuse angle. The paper was laid upon this and carefully fitted to adjusting pins; the frisket, a thin frame holding a sheet of paper cut to the size of the form, was folded over the paper to protect it, to steady it and to raise the paper from the type after the impression. This press has been improved in construction, but in prin ciple and form substantially the same press is widely used to-day in the United States as a proof press and for the special work for which it is fitted. Its capacity is about 250 sheets an hour printed on one side. Alike in principle and construction, though differing in detail of depressing and raising the platen, is the Albion hand press as widely used in Great Britain.