Method of loading metal printing plates on a vacuum drum
AssigneeCreo Products Inc.
InventorDaniel Gelbart
Life of this patent
Estimating the term…
Abstract
Metal printing plates can be loaded onto a drum and held in place by vacuum alone if flat plates are given a permanent curl by a set of four rollers. Same rollers cancel out the curl when plate is unloaded from drum. The invention is useful for Computer-to-Plate and Computer-to-Press systems.
Claims22
A method of loading a printing plate onto a cylinder, the method comprising the steps of:
- imparting a curvature to said printing plate proximate said cylinder;
- and
- loading the printing plate onto said cylinder substantially concurrently with said imparting step, the curvature imparted being such that the printing plate will snugly fit around the cylinder.
A method of loading a printing plate onto an inner surface of a cylinder, the method comprising the steps of:
- imparting a curvature to said printing plate by bending said plate beyond the elastic limit, said imparting step performed proximate to said cylinder;
- and loading the printing plate onto the inner surface of said cylinder substantially concurrently with said imparting step, the curvature once imparted being such that the printing plate fits snugly around the inside of said cylinder.
A printing plate loading system, for use with a printing plate and a plate imaging system, the printing plate loading system comprising:
- (a) a cylinder;
- (b) a cluster of at least three rollers located proximate the cylinder and operative to impart a curvature to the printing plate and to load the printing plate onto the cylinder as the curvature is imparted to the printing plate, the curvature once imparted being such that the printing plate fits snugly around the cylinder, said cluster of at least three rollers comprising:
- (i) a pair of pinch rollers having a gap therebetween to snugly receive the printing plate as a flat sheet, wherein at least one of the pinch rollers is motorized so as to feed the printing plate through the gap;
- and
- (ii) a bend roller located proximate said pinch rollers and operative to bend the printing plate around said cylinder as it emerges from between said pinch rollers.
A printing plate loading system, for use with a printing plate and a plate imaging system, the printing plate loading system comprising:
- (a) a cylinder having a perforated outer surface, said cylinder in fluid communication with a vacuum pump operative to evacuate air from within the cylinder so as to allow a vacuum generated by the vacuum pump to reach said perforated outer surface;
- and
- (b) a plurality of rollers located proximate the cylinder and operative to impart a curvature to the printing plate and to load the printing plate onto said cylinder as the curvature is imparted to the printing plate, the curvature once imparted being such that the printing plate fits snugly around said cylinder.
A printing plate loading system, for use with a printing plate and a plate imaging system, the printing plate loading system comprising:
- (a) a cylinder having an outer surface and an inner cylindrical surface, said outer surface having an opening so as to receive the printing plate;
- and
- (b) a plurality of rollers located proximate the cylinder and operative to impart a curvature to the printing plate and to load the printing plate through said opening and inside said cylinder onto the inner cylindrical surface as the curvature is imparted to the printing plate, said curvature being such that the printing plate fits snugly within said cylinder.
A method of loading a printing plate having a soft metal substrate onto a cylinder, the method comprising the steps of:
- feeding said printing plate as a flat sheet between a pair of pinch rollers proximate the cylinder;
- bending the printing plate as it emerges from between the pinch rollers with a third roller so as to impart a curvature to the printing plate such that its radius is slightly less than a radius of the cylinder;
- and
- automatically loading the printing plate onto said cylinder as the curvature is imparted to said printing plate;
- wherein the curvature is such that the printing plate fits snugly around the cylinder.
Dependencies are inferred from the claim text.