Installation to make security documents and security documents made in such an installation

Abstract: The installation has a stirring tank (1) into which process water has access through a duct (2) working with level control means (3) and (4), and the planchettes from a batcher (5), the tank (1) having a double propeller (7) agitator (6) in order for the mixture to be perfectly homogenized. The stirring tank (1) is provided with a number of outlets (8) to which respective ducts (9) are coupled to link the said tank to a number of nozzles (10) that are in turn positioned over the mould (11) to make the security paper, a special feature being that each such duct (9) is provided with a pump (12) working with a pressure and flow regulator (13) in order in turn for the supply from the said nozzles (10) to be perfectly homogeneous.

Description: OBJECT OF THE INVENTION The present invention relates to an installation that is specifically designed to make security documents, such as paper used as a printing base to obtain banknotes, viz. paper money, and in particular security documents in which the pulp making up the paper will be provided with planchettes, or as appropriate also with fibrils that "personalize" the paper to enhance its security, which planchettes or fibrils are arranged as bands on the paper surface, in the flow direction of the sheet during production. The invention also relates to the security documents that result from the practical use of the said installation. BACKGROUND OF THE INVENTION It is a known fact that in making paper for security documents of this kind it is a wholly widespread practice to provide planchettes and/or fibrils with special characteristics to the pulp making up the paper, in the latter's production process on the respective forming mould or cloth, in order for both the characteristics of the planchettes or fibrils and their specific apportionment to cause the document to be "personalized" as aforesaid. Nowadays, and in applying the planchettes or fibrils in bands, these are allowed to move down towards the papermaking mould through flexible pipes and from a constant-level box, the downward movement of the planchettes being simply due to gravity, a twofold problem arising from a large deficiency in flow control which at times leads to jamming, and to the supply of planchettes being cut off, and at others to a similarly undesirable over-apportionment. On the other hand and even in the merely theoretical event of the batching remaining constant in time, the latter may only be changed or regulated by changing the concentration or dispersion of the planchettes in the water of the planchette feed tank. DESCRIPTION OF THE INVENTION The installation to make security documents subject of the invention as defined by the appended claims fully solves the above twofold problem, succeeding in particular to achieve an optimal flow regulation and to sustain such flow, once regulated, almost invariable in time. Furthermore, the distribution of the planchettes on the paper is also more homogeneous and the same are better attached to the paper surface, to prevent the planchettes from becoming detached during the subsequent printing process. More specifically, the installation to make security documents subject of the invention is structured with a stirring tank fed by the process water and a planchette batcher and with any other alternative or supplementary additive that is deemed necessary or expedient, for instance security fibrils, the said stirring tank having a number of outlets to feed respective nozzles, that are arranged in a row and crosswise to the papermaking mould, a special feature however being that each of the ducts linking the said outlets and the relevant nozzles is provided with a drive pump, working with a pressure and flow regulator thereby to allow the flow or batching of planchettes onto the forming mould, to which the pulp fibres making up the paper are simultaneously applied, to be regulated at will, the planchettes being uniformly distributed by the likewise uniform distribution of the nozzles and the perfect flow regulation at each of them. The fact that the system relies on manifold nozzles means that they can each form a band. Another characteristic of the invention is that the stirring tank has a double propeller agitator, viz. two propellers at a different height, their direction of rotation causing the contents of the said tank to move towards its bottom, thereby for the homogenization conditions within the said tank to be optimal. It is also provided, as another characteristic of the invention, that the said drive pumps located at each of the outlets from the stirring tank are membrane or diaphragm pumps to avoid the same from damaging the planchettes or security elements. Finally and as yet another characteristic of the invention, the nozzles batching the planchettes are positioned just where the sheet of paper begins to for, for the said planchettes to meet with the first fibres reaching the mould, and hence while most of the pulp fibres making up the paper remain under the planchette, some fibres remain above the same, to act as means holding the same and guaranteeing the stability thereof, in particular during the subsequent printing stage. DESCRIPTION OF THE DRAWINGS In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, a single sheet of drawings is attached to the specification which, while purely illustrative and not fully comprehensive, diagrammatically shows an installation to make security documents, established in accordance with subject hereof. PREFERRED EMBODIMENT OF THE INVENTION The figure shows that the installation subject hereof is structured with a stirring tank (1) where the level of process water arriving through a duct (2) is kept constant with the assistance of a valve (3) controlled by a float (4) or like system, the process water being provided with the planchettes with the assistance of a planchette batcher (5) and as appropriate with any other kind of adjuncts, such as the classic security fibrils. The stirring tank (1) is internally fitted with an agitator (6) having a double propeller (7), the direction of rotation of the agitator (6) shaft being such that the said double propeller (7) tends to drive the mixture of water and planchettes towards the bottom of the stirring tank (1), thereby to optimally stir the mixture and hence also to optimally homogenize the same. The lower tank area is provided with a number of outlets (8) for the same number of ducts (9) that link the same to respective outlet nozzles (10) arranged in a transverse row on the mould (11) to make up the security paper. Each such duct (9), and in accordance with one of the essential features of the invention, is provided with a pump (12) equipped with a flow and pressure regulator (13) in order for such regulators to afford a perfect control so that batching by the various nozzles (10) along the transverse working line they define is also perfectly homogeneous, or in other words, for the distribution of the planchettes on the surface of the security paper likewise to be perfectly homogeneous. More specifically, the planchettes are incorporated to the paper in the last place, viz. from the nozzles (10) to the papermaking mould (11), when the water flows in which the planchettes are dispersed physically drop due to simple gravity, jointly with the indraught there is from outside at the forming cloth (the effect being the same causing paper to be formed when the pulp fibres are laid on the forming mould or cloth) to be integrated in the newly formed paper mass. In this sense, as aforesaid and in accordance with yet another characteristic of the invention, by adjusting the nozzles (10) to batch the planchettes just where the paper sheet begins to form so that the planchettes meet the first fibres to reach the mould, while most of the paper fibres remain under the planchette in making the said paper, some remain above the said planchettes to act as a holding means therefor and, hence, afford a better attachment of the said planchettes. A security document and in particular paper with which to prepare security documents is thus made, with the planchettes playing an essential role in providing paper with its security features being better attached to the same inasmuch as instead of being merely adhered to one of the faces thereof, they are held by some of the paper's pulp fibrils.

Claims: An installation to make security documents comprising a sheet of paper to which planchettes and optionally other types of security elements such as security fibrils are incorporated, said installation comprising a papermaking mould (11), means for applying paper pulp fibres onto the papermaking mould and means for supplying a mixture of water and planchettes and optionally other types of security elements to the papermaking mould (11), characterized in that said means for supplying the mixture of water and planchettes and optionally other types of security elements to the papermaking mould comprise a stirring tank (1) provided with a double propellor (7) agitator (6), a duct (2) for supplying water into the stirring tank (1), a planchette batcher (5) for supplying planchettes into the stirring tank (1) and optionally batchers for supplying other types of security elements, such as security fibrils, into the stirring tank (1), the stirring tank (1) being provided with a number of outlets (8) connected through respective ducts (9) to the same number of nozzles (10) for pouring the mixture of planchettes and water onto the papermaking mould (11), each duct (9) connecting the stirring tank outlets (8) to the nozzles (10) being provided with a pump (12) working with a pressure and flow regulator (13) through which each nozzle (10) can be individually regulated, thus guaranteeing that the supply of planchettes is perfectly uniform throughout the whole set of nozzles (10). An installation according to claim 1, characterized in that the outlets (8) are located in the lower part of the stirring tank (1) and the rotary movement of the agitator (6) is such that its double propellor (7) tends to move the mixture of planchettes and water towards the bottom of the stirring tank (1). An installation according to claim 1 or 2, characterized in that the pumps (12) provided in each of the ducts (9) connecting the stirring tank outlets (8) to the nozzles (10) are membrane or diaphragm pumps. An installation according to any of the preceding claims, characterized in that the nozzles (10) are positioned with respect to the papermaking mould (11) just where the paper sheet begins to form so that the planchettes meet the first pulp fibres to reach the papermaking mould (11). An installation according to any of the preceding claims, characterized in that the nozzles (10) are manifold nozzles which each determine the formation of a band.

Inventors: CAMACHO JAVIER, DE LA VEGA LIBORIO, GUTIERREZ CARLOS, PEREZ VICTORIANO, RODRIGUEZ JOSE LUIS, CAMACHO, JAVIER, DE LA VEGA, LIBORIO, GUTIERREZ, CARLOS, PEREZ, VICTORIANO, RODRIGUEZ, JOSE LUIS, Rodriguez, José Luis
Applicants: NACIONAL MONEDA TIMBRE, FABRICA NACIONAL DE MONEDA Y TIMBRE
Application year: 1992
Main classification: D21F1
IPC codes: D21F1