Abstract: The present invention is concerned with a printing plate of which image formation is done by photoirradiation, having a front side covered waith a peelable or removable protective layer which contains a photofading material. The printing plate is safe against fogging to light and can be used under ordinary illumination.

Abstract: A printing plate formed of a substrate and laminated thereon in the following order a primer layer and a photosensitive layer containing a quinonediazide compound and a silicone rubber layer, wherein the primer layer contains 0.1 to 25% by weight of a quinonediazide group. The printing plate of the present invention is excellent in dot reproduction, hardly causes cracking in the photosensitive layer, and has a wide latitutde in production.

Abstract: Provided is a dry planographic printing plate containing on a base substrate a mixture which mixture comprises an organopolysiloxane; an alkoxy silane as a cross-linking agent represented by the formula R.sub.4-a-b R'.sub.a Si(OR").sub.b wherein a is 0 or 1, b is 2 or 3 and a+b is at most 3, R is an organic group containing a polar group or double bond and OR" is an alkoxy group; and a compound as a cross-linking catalyst represented by the formula (R.sup.1 O)(R.sup.2 O)(R.sup.3 O)(R.sup.4 O)M wherein M is titanium or zirconium, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each an organic group.

Abstract: A waterless planographic printing plate having toner image areas of ink receptivity and non-image areas of ink releasability is provided, which plate has a substrate and an overlying layer coated on the substrate. The overlying layer is predominantly comprised of a reaction product of 50 to 99% by weight of a polymeric material having, on the average, at least two hydroxyl groups per molecule and exhibiting a high adhesion to the ink-receptive toner, and 1 to 50% by weight of an organopolysiloxane having hydroxyl end groups. The overlying layer preferably consists of a relatively thin surface layer substantially composed of the organopolysiloxane, and a relatively thick inner layer sandwiched between the surface layer and the substrate and having an islands-in-sea heterophase structure composed of the organopolysiloxane islands substantially uniformly dispersed in the sea of the polymeric material.