Abstract:
There is described a multicolour letterpress printing press, in particular a numbering press, comprising a printing group (50) with at least a first letterpress (e.g. numbering) cylinder (51) and a second letterpress cylinder (52) which are inked by an associated inking system (60, 71, 72, 81, 81 a, 81 b, 82, 82a, 82b). The inking system (60, 71, 72, 81, 81 a, 81 b, 82, 82a, 82b) comprises (i) a first inking device (81) supplying ink to a first chablon cylinder (71), (ii) at least a second inking device (82) supplying ink to a second chablon cylinder (72), and (iii) an ink-collecting cylinder (60) contacting the first and second chablon cylinders (71, 72) and the first and second letterpress cylinders (51, 52). The ink-collecting cylinder (60) collects a first ink pattern (A, D) from the first chablon cylinder (71) and a second ink pattern (B, C) from the second chablon cylinder (72). As a result, a first multicolour pattern of inks (A-D) is formed on the ink-collecting cylinder (60), which first multicolour pattern of inks (A-D) is transferred onto the first letterpress cylinder (51). The ink- collecting cylinder (60) further collects a third ink pattern (A, D ) from the first chablon cylinder (71) and a fourth ink pattern (B, C ) from the second chablon cylinder (72), thereby forming a second multicolour pattern of inks (A "D ) on the ink-collecting cylinder (60), which second multicolour pattern of inks (A "D ) is transferred onto the second letterpress cylinder (52).
Abstract:
There is described an intaglio printing press (1; 1 *) comprising a plate cylinder (8) carrying one or more intaglio printing plates, the plate cylinder (8) receiving ink from an inking system (9, 20, 23; 20*, 23*) having a plurality of chablon cylinders (23; 23*) transferring ink directly or indirectly onto the plate cylinder (8), the intaglio printing press (1; 1 *) comprising an adjustment system acting on the chablon cylinders (23; 23*) in order to compensate elongation of the one or more intaglio printing plates. The adjustment system comprises, for each chablon cylinder (23; 23*), an adjustable drive unit, which adjustable drive unit (25) is interposed between the chablon cylinder (23; 23*) acting as a rotating output body of the adjustable drive unit (25) and a driving gear (100) acting as a rotating input body of the adjustable drive unit (25). The adjustable drive unit (25) is designed to allow selected adjustment of a rotational speed of the chablon cylinder (23; 23*) with respect to a rotational speed of the driving gear (100). In an adjusting state of the adjustable drive unit (25), driving into rotation of the chablon cylinder (23; 23*) is adjusted over each revolution of the chablon cylinder (23; 23*) by means of an adjustment motor (300) of the adjustable drive unit (25). In a non-adjusting state of the adjustable drive unit (25), the adjustment motor (300) is inoperative and driving into rotation of the chablon cylinder (23; 23*) is performed exclusively mechanically via the adjustable drive unit (25), the chablon cylinder (23; 23*) rotating at a same rotational speed as the driving gear (100).
Abstract:
There is described a printed security feature (10) provided onto a printable substrate, which printed security feature includes a printed area (11) with at least a first printed section consisting of a multiplicity of geometric elements (GE, 15) printed with a given distribution over the printed area. The geometric elements are printed with at least first and second inks which exhibit the same or substantially the same optical appearance when illuminated with visible white light, such that the printed security feature produces a first graphical representation (A1) when illuminated with visible white light. At least the first ink is an ink which responds to non-visible light excitation by producing a characteristic optical response differentiating the first ink from the second ink. The printed security feature produces a second graphical representation (B1) when illuminated with non-visible light, which exhibits a distinctive two- dimensional graphic element (B) which is revealed only when the printed security feature is illuminated with non-visible light. The first printed section is subdivided into at least first and second printed portions (P1, P2), adjacent to the distinctive two-dimensional graphic element, and a third printed portion (P3), inside boundaries (200) of the distinctive two-dimensional graphic element. In the first, respectively second printed portion, the geometric elements are printed with the first, respectively second ink. In the third printed portion, the geometric elements are subdivided into first and second contiguous portions (GE_a, GE_b) which are respectively printed with the first and second inks. The first and second inks are printed in register one with respect to the other so that the boundaries of the distinctive two-dimensional graphic element are not visible when the printed security feature is illuminated with visible white light and the distinctive two-dimensional graphic element only becomes visible when the printed security feature is illuminated with non-visible light.
Abstract:
There is described a printed security feature (10) provided onto a printable substrate, which printed security feature includes a printed area (11) with at least a first printed section consisting of a multiplicity of geometric elements (GE, 15) printed with a given distribution over the printed area. The geometric elements are printed with at least first and second inks which exhibit the same or substantially the same optical appearance when illuminated with visible white light, such that the printed security feature produces a first graphical representation (A1) when illuminated with visible white light. At least the first ink is an ink which responds to non-visible light excitation by producing a characteristic optical response differentiating the first ink from the second ink. The printed security feature produces a second graphical representation (B1) when illuminated with non-visible light, which exhibits a distinctive two- dimensional graphic element (B) which is revealed only when the printed security feature is illuminated with non-visible light. The first printed section is subdivided into at least first and second printed portions (P1, P2), adjacent to the distinctive two-dimensional graphic element, and a third printed portion (P3), inside boundaries (200) of the distinctive two-dimensional graphic element. In the first, respectively second printed portion, the geometric elements are printed with the first, respectively second ink. In the third printed portion, the geometric elements are subdivided into first and second contiguous portions (GE_a, GE_b) which are respectively printed with the first and second inks. The first and second inks are printed in register one with respect to the other so that the boundaries of the distinctive two-dimensional graphic element are not visible when the printed security feature is illuminated with visible white light and the distinctive two-dimensional graphic element only becomes visible when the printed security feature is illuminated with non-visible light.
Abstract:
There is described an intaglio printing press (1; 1*) comprising an intaglio cylinder (8) and an ink wiping system (10) with a rotating wiping roller assembly (11) contacting a circumference of the intaglio cylinder (8) for wiping excess ink from the surface of the intaglio cylinder (8), a rotational speed of the wiping cylinder being adjustable with respect to a rotational speed of the intaglio cylinder (8). The intaglio printing press (1; 1*) comprises an adjustable drive unit (25), which adjustable drive unit (25) is interposed between the wiping roller assembly (11) acting as a rotating output body of the adjustable drive unit (25) and a driving gear (100) coupled to the intaglio cylinder (8) and acting as a rotating input body of the adjustable drive unit (25). The adjustable drive unit (25) is designed to allow selected adjustment of a rotational speed of the wiping roller assembly (11) with respect to a rotational speed of the driving gear (100). In an adjusting state of the adjustable drive unit (25), driving into rotation of the wiping roller assembly (11) is adjusted by means of an adjustment motor (700) of the adjustable drive unit (25). In a non-adjusting state of the adjustable drive unit (25), the adjustment motor (700) is inoperative and driving into rotation of the wiping roller assembly (11) is performed exclusively mechanically via the adjustable drive unit (25), the wiping roller assembly (11) rotating at a defined rotational speed with respect to the rotational speed of the intaglio cylinder (8).
Abstract:
There is described a printed security feature (1) provided onto a printable substrate, which security feature includes a printed area (100) consisting of a multiplicity of adjacent rectilinear and/or curvilinear elements (110, 120) printed with a given spatial frequency. The rectilinear and/or curvilinear elements are printed with at least first and second inks which exhibit the same or substantially the same optical appearance when illuminated with visible white light, such that the security feature produces a first graphical representation when illuminated with visible white light, at least the first ink being an ink which responds to non- visible light excitation by producing a characteristic optical response differentiating the first ink from the second ink. The security feature produces a second graphical representation when illuminated with non-visible light, which second graphical representation exhibits a distinctive two-dimensional graphic element (B) which is revealed only when the security feature is illuminated with non-visible light. Inside boundaries (160) of the distinctive two-dimensional graphic element, a part (P3) of the rectilinear and/or curvilinear elements is printed with a combination of the first and second inks, the rectilinear and/or curvilinear elements being subdivided, within that part, into first and second juxtaposed sections (110a, 110b, 120a, 120b) which are respectively printed with the first ink and with the second ink. Outside the boundaries of the distinctive two-dimensional graphic element, portions (P1, P2) of the rectilinear and/or curvilinear elements are printed with only one of the at least first and second inks. The at least first and second inks are printed in register one with respect to the other so that the boundaries of the distinctive two-dimensional graphic element are not visible when the security feature is illuminated with visible white light and the distinctive two-dimensional graphic element only becomes visible when the security feature is illuminated with non-visible light.
Abstract:
There is described a method for checking the authenticity of security documents, in particular banknotes, wherein authentic security documents comprise security features (41-49; 30; 10; 51, 52) printed, applied or otherwise provided on the security documents, which security features comprise characteristic visual features intrinsic to the processes used for producing the security documents. The method comprises the step of digitally processing a sample image of at least one region of interest (R. o. I.) of the surface of a candidate document to be authenticated, which region of interest encompasses at least part of the security features, the digital processing including performing a decomposition of the sample image by means of wavelet transform (WT) of the sample image. Such decomposition of the sample image is based on a wavelet packet transform (WPT) of the sample image, preferably a so-called two-dimensional shift invariant WPT (2D-SIWPT)