Now, it has been found that this construction with a collector inking cylinder of the same diameter as the plate cylinder, which as it generally carries three intaglio plates therefore has a relatively large diameter, represents a bulky volume and requires a lot of space what is more, such a machine is expensive to manufacture and to install, because according to a widely held maxim in the field of printing, installation costs increase as a function of the cube of the diameter of the cylinders used.
In this known machine, it was thought advantageous, in order to ensure perfect print quality, for the diameter of the collector inking cylinder to be equal to or to represent a multiple of the diameter of the plate cylinder. To at least four colors, this machine offers theĪttractive possibility of printing a complete note with a main design and the safety background in a single pass, for example using one color for the main design and three colors for the safety background. The invention relates to an intaglio printing machine for printing securities, particularly bank notes, comprising a main structure, a plate cylinder with at least one printing plate, an impression cylinder, a wiping device and an inking system consisting of a collector inking cylinder which has an elastic surface interacting with the printing plates, of at least four color-selector cylinders placed one beside the other around part of the circumference of the collector inking cylinder and having reliefs that correspond to the colored regions to be printed in the various colors and in contact with the periphery of the collector inking cylinder, and of an inking device associated with each color-selector cylinder and mounted in a mobile inking carriage.Īn intaglio printing machine of this kind, for printing securities therefore comprising an indirect inking system that uses a collector inking cylinder is known from the Applicant's patent EP 0 406 157. The lateral walls of the inking carriage (9), on the same side as the color-selector cylinders, each comprise a recess (15) which is dimensioned in such a way that when the inking carriage (9) is in the working position, the color-selector cylinders (7b, 7c) which are between said two extreme color-selector cylinders (7a, 7d) lie wholly in the space defined by said recess (15). The two extreme color-selector cylinders (7a, 7d) are placed so that they are approximately diametrically opposed with respect to the collector inking cylinder (5).
The ratio between the diameter of the collector inking cylinder (5) and the diameter of the plate cylinder (4) is equal to 2/3. The intaglio printing machine comprises a main structure (6), a plate cylinder (4), an impression cylinder (3), a wiping device (10) and an inking system consisting of a collector inking cylinder (5), of at least four color-selector cylinders (7a to 7d), and of an inking device (8a to 8d) associated with each color-selector cylinder (7a to 7d) and mounted in a mobile inking carriage (9).