Abstract: A printing mechanism is provided with a counter-balanced hammer bank such that the hammer bank and a counterweight are oppositely reciprocated by a pair of cams mounted on a vertically oriented cam shaft. Vibration of the printer even at high speed can be eliminated by completely dynamically balancing the system.

Abstract: A developing process suitable to treat a positive photosensitive lithographic printing plate comprising a photosensitive layer containing, as the photosensitive constituent, an o-quinonediazide compound provided on an aluminium plate. A positive photo-sensitive lithographic printing plate is exposed imagewise and then developed with a developing solution containing an aqueous solution of an alkali metal silicate in which the alkali metal is essentially constituted by potassium. With the method, development treatment can be conducted stably for a long period without generating insolubes in the developing solution even when an extremely large quantity of positive photosensitive lithographic plates are treated.

Abstract: A printing mechanism is provided with a counter-balanced hammer bank such that the hammer bank and a counterweight are oppositely reciprocated by a pair of coaxial, identical, orthogonally oriented cams. Vibration of the printer even at high speed can be eliminated by completely dynamically balancing the system.