A printing apparatus having a plurality of blanket cylinders normally-contacting to impression cylinders, plate cylinders normally-contacting to the respective blanket cylinders, and a ink coating apparatus, a printing apparatus, an imaging apparatus, an imaging method, an imaging medium, a printing system, and a printing method. The valve system further includes a backflow prevention system to prevent flow of the first pressurized fluid through the second inlet and to prevent flow of the second pressurized fluid through the first inlet port. The artificial anti-ferromagnet is magnetically coupled to the anti-ferromagnet, and includes first and second magnetic layers, and a coupling layer interposed therebetween, the first and second magnetic layers having different Curie point temperatures. The bell crank is coupled to a linear actuator for rotating the rock shaft relative to the wing frame segments. The sensor is also provided with locking means that can either lock the geophone 4 relative to the housing, or can allow the geophone to rotate within the housing.