Image Number 2 for United States Patent #6640713.
An improved offset printing press has a single plate blanket image (PBI) cylinder for holding an image formed on a thin film printing plate affixed thereto. The plate may be from 0.5 to 25 microns thick and has a thin layer of ink repelling material coated thereon. The plate is imaged, after being affixed to the PBI cylinder, by ablating selective portions of the ink repelling coating. The PBI cylinder is constructed to hold the printing plate by vacuum techniques, and apparatus to load and unload the plate is associated with the PBI cylinder. Because of the thinness of the printing plate, the PBI cylinder is a compliant surface, capable of printing on an inelastic media covered impression cylinder. In addition, unique inking apparatus is provided to transfer ink to the imaged printing plate. Variations of the press include a four color press utilizing a single PBI cylinder.