EP0091713B1 - Method of making ready printed, numbered and cut to size bank notes, and automatic cutting machine for carrying out the method - Google Patents

Description

The invention relates to a method according to the preamble of claim 1 and to an automatic cutting machine for performing the method according to DE-A-2757186.

When producing notes of value, in particular banknotes, notes of sheet with a certain number of benefits, that is to say with a certain number of security prints arranged in a matrix, are generally produced first and then these sheets are stacked step by step in strip layers and then the strip layers in bundles of notes cut, whereby the individual notes of the bundle receive their finished format. When using automatically working cutting machines, the feed lengths for the step-by-step feed of the sheet stacks and the strip positions are fixed based on a feed program that has been set once, depending on the size of the banknotes or the desired bill format. The accrued, cut vouchers are of course all the same size. This uniform size of notes is advantageous for the automatic further processing, sorting and packaging of the bundles of notes.

Now, for aesthetic reasons and also for reasons of security against forgery, it is desirable that the printed image of a note is always centered within the edges of the note or, as is said, always exactly in the mirror. This condition has so far not always been met exactly if the security print includes direct gravure printing, in particular a steel engraving print, in which the printing plates are subjected to a very high contact pressure and undergo a gradual expansion under the action of these forces during operation, that is to say become increasingly longer and also wider, this widening becoming larger along the pressure plate in the direction opposite to the direction of rotation of the plate cylinder. The schematic shape of such a deformed, approximately trapezoidal printing plate corresponds to the outline 11 'in FIG. 2, which will be explained in more detail later. In accordance with the lengthening and widening of the printing plate, the size and positions of the prints change, so that the sheet stacks are cut automatically with constant feed lengths Completely cut notes of value are created, in which the printed image moves more and more out of its centered position with increasing number of prints and therefore the difference in the widths of the margins becomes more and more striking.

The invention has for its object to provide a method which, despite a printing plate deformation occurring in the course of operation, always allows you to obtain coupons when the sheet stacks are cut, which have at least approximately centered printed images with respect to the edges of the coupons.

This object is achieved according to the invention in the characterizing part of claim 1 and, with regard to the cutting machine for performing the method according to the invention, by the features specified in claim 14.

In the simplest case, the change in the feed lengths can be carried out manually on the basis of an experience program which has been set up empirically and possibly also theoretically for the printing plates in question. One then begins to readjust the feed lengths as soon as the deformation of the printing plate takes on a dimension which is disturbing in practice, which can be the case, for example, after 50,000-100,000 prints. After each additional 50000-100000 prints, the lengths of the feed movements can be changed and adjusted accordingly. The readjustments to be made to the original feed program can also be carried out on the basis of a regular inspection and measurement of the printing plate, for example after every 50,000 or 100,000 prints.

It is also possible to control the feed lengths automatically by means of a computer on the basis of a program prepared for each type of printing plate, which varies with an increasing number of prints.

A change in length of the individual feeds can be carried out particularly precisely and easily with commercially available feed devices, which are known under the name linear amplifier. These linear amplifiers have a hydraulic cylinder-piston system, the metered pressure medium supply to the hydraulic cylinder being carried out with the aid of a stepper motor which briefly opens the pressure medium inlet valve with each revolution; as a result, a precisely metered, small amount of pressure medium is supplied to the cylinder during one revolution of the stepping motor in such a way that the piston carries out a feed of, for example, 0.1 mm. Such a hydraulically controlled feed also works with a sufficiently short response time.

A preferred embodiment of the method according to the invention is to apply printing marks on the printing plate, which define the later cutting lines and inevitably take part in the deformations of the printing plate, and to control the feed devices by reading devices which read the markings made during the printing process. These markings are printed on the edges of the sheets and, if appropriate, on the areas lying between the printed images, which are cut off as waste strips during later sheet edge trimming or later intermediate cuts. In this way, the cutting dimension Automatically control the machine as a function of the positions of these print markings so that banknotes are always cut whose print image is centered correctly or at least much more precisely than before.

The change in the feed lengths when cutting naturally means that, if one does not make intermediate cuts, the finished cut notes of value vary slightly in size, depending on the deformation of the printing plates. However, the advantage achieved, namely that the printed image of the notes of value is always at least approximately exactly in the mirror, is to be rated much higher than the somewhat different size of the notes of value obtained. This changing size is in fact not noticeable in practice and could at best be determined by exact measurements of several notes of value; the slightly different size of the banknotes is practically negligible when it is processed into packaged bundle packages. In contrast, an incorrectly centered printed image immediately notices the viewer of a note.

However, if it is important that all notes of value should have the same constant format, it is of course possible to work with intermediate cuts, which is a somewhat more complex process; in this case the waste strips must generally be at least about 2 mm wide so that perfect cuts can be made.

In general, the deformation effect of the base plate is more important in the longitudinal direction than in the transverse direction, so that under certain circumstances the feed lengths only need to be changed for the strip cuts made parallel to the gripper edge and centering correction can be dispensed with for the ribbon cuts. However, it is also conceivable that, in certain cases, only a centering correction is made for the bundle cuts and the strip cuts are made with fixed feed lengths.

Advantageous further refinements of the invention are specified in the dependent claims.

• Fig. 1 die schematische Ansicht der wesentlichen Verarbeitungsstationen bei der Fertigung von Wertscheinen gemäß der vorliegenden Erfindung,
• Fig. 2 die schematische Ansicht eines mit einer neuen, unverformten Druckplatte bedruckten Wertscheinbogens, welcher 6 x 4 = 24 Wertscheindrucke bzw. Einzelnutzen aufweist und auf welchem die späteren Schnittlinien gestrichelt dargestellt sind; strichpunktiert ist der etwa trapezförmige Umriß des verzerrten Gesamtdruckbildes aller Wertscheindrucke veranschaulicht, wie es eine nach zahlreichen Drucken entsprechend gedehnte Druckplatte erzeugt, wobei die Verzerrung, ebenso wie in den folgenden Figuren, aus Gründen der Anschaulichkeit übertrieben und nicht maßstabsgerecht dargestellt ist,
• Fig. 3 den Bogen nach Fig. 2 mit dem verzerrten Gesamtdruckbild und den strichpunktiert angedeuteten, späteren Schnittlinien, deren Lagen aufgrund der Änderungen der Vorschublängen korrigiert sind,
• Fig. 4 den das Bündelschneidwerk nach Fig. 1 einschließenden Bereich mit den sechs Streifenlagen in schematischer, vergrößerter Darstellung mit den zugeordneten Vorschubeinrichtungen,
• Fig. 5 einen 4 x 4 = 16 Wertscheindrucke aufweisenden Bogen mit verzerrtem Druckbild, der unter Verwendung von Zwischenschnitten verarbeitet wird und auf dem die späteren Schnittlinien gestrichelt angedeutet sind, und
• Fig. 6 eine der Fig. 4 entsprechende Darstellung, welche den Vorschub der vier Streifenlagen des Bogens nach Fig. 5 beim Bündelschnitt veranschaulicht.

The invention is explained in more detail with reference to the drawings. It shows

• 1 is a schematic view of the essential processing stations in the manufacture of notes of value according to the present invention,
• FIG. 2 shows the schematic view of a note sheet printed with a new, undeformed printing plate, which has 6 × 4 = 24 note impressions or single use and on which the later cut lines are shown in broken lines; Dash-dotted lines illustrate the roughly trapezoidal outline of the distorted overall printed image of all security impressions, as is produced by a printing plate which has been stretched accordingly after numerous prints, the distortion, as in the following figures, being exaggerated for reasons of clarity and not to scale,
• 3 the sheet according to FIG. 2 with the distorted overall printed image and the later cut lines indicated by dash-dotted lines, the positions of which have been corrected due to the changes in the feed lengths,
• 4 the area including the bundle cutting unit according to FIG. 1 with the six strip layers in a schematic, enlarged illustration with the assigned feed devices, FIG.
• 5 shows a sheet having 4 x 4 = 16 security impressions with a distorted printed image, which is processed using intermediate cuts and on which the later cut lines are indicated by dashed lines, and
• FIG. 6 shows a representation corresponding to FIG. 4, which illustrates the advance of the four strip layers of the sheet according to FIG. 5 in a bundle cut.

1 schematically shows those processing stations at which method steps according to the invention take place. It is assumed that the coupons have already been printed on both sides in offset printing and also on one side in steel engraving. The last printing process for the note sheets prepared in this way is that the other sheet side is also printed with an engraved image. The engraving printing unit 20 provided for this purpose is indicated schematically in FIG. 1. The sheets of banknotes, which are available at the entrance of the stitch printing unit 20 in the form of an input stack S1, pass through the stitch printing unit 20 one after the other in a known manner and are collected at its outlet on an output stack S2. As indicated, the individual, fully printed sheets 10 each have 24 security impressions or so-called individual benefits, which are arranged in a matrix in six rows with four security impressions each. In Fig. 2, such a sheet 10 is shown enlarged with its six rows of bills 1 to 6; the banknotes later cut to format are designated by 12 and the actual banknote impressions surrounded by an unprinted border are designated by 13.

As is known, the individual sheets are pulled by sheet grippers which hold the front sheet edge as they pass through the printing units. This sheet edge lying at the front as it passes through the printing units in the transport direction F _o is the so-called gripper edge 14 (FIGS. 1 and 2), and the value rows 1 to 6 are parallel to this gripper edge 14, that is to say transversely to the direction of the sheet passing through the printing units, oriented. The remaining three sheet edges are labeled 15, 16 and 17.

The finished printed sheets 10 of the stack S2 are usually subjected to a visual quality control, in which sheets are discarded with misprints, and then by one for numbering the individual uses Input stack S3 is entered into a numbering machine 21 and stored at its output on an output stack S4.

The numbered sheets are then fed one after the other to an automatic cutting machine. 1, a sheet stack S5 is first transported in the direction of the arrow along a transport path 22 to the entrance of a cutting path 24 and brought into a defined starting position P1, in which all sheets 10 of the stack are aligned with their gripper edges 14 at a stop 23. During the subsequent transport of the stack along the cutting section 24 in the direction of the arrow F1 to the strip cutting unit 27 and during the gradual feed within this strip cutting unit 27, the gripper edges 14 form the trailing edge of the sheet and thus the reference edge of the sheet stack which is decisive for the strip cut, on which finger-like slides are known an automatic feed device 26 to feed the stacks.

On the cutting section 24, in front of the strip cutting unit 27, there is a longitudinal cutting unit 25 on the side, at which the stacks are stopped and in which a side edge trimming takes place. The edge of the sheet is cut here which forms the rear edge of the strip layers during the later bundle cut, that is, in the example considered, the left side edge 15 of the sheet 10 in the feed direction. Then, in the strip cutter 27 designed as a cross cutter, the edge is first cut at the front of the stack of the front edge 16 of the sheet 10 (FIG. 2), then the stack is divided step by step into its six strip layers 18, which correspond to the six value rows 1 to 6, and finally the rear edge trim is on the back of the last strip layer the gripper edge 14 executed. The waste paper from the edge trimmings falls through a waste flap. When a stack is cut, the following stack is automatically fed.

Behind the strip cutting unit 27 there is a banding station 29 with a number of individual banding devices corresponding to the number of blanks per strip, in the example considered four banding devices that are operated simultaneously in each work step, in such a way that each layer of strips 18 is simultaneously connected to the four note or Benefit positions with a pre-glued band 129 is surrounded.

The finished banded strip layers 18 are first removed from the banding station 29 in the direction of the arrow in the longitudinal direction of the strip and then moved along the transport path 35, transversely to the longitudinal direction of the strip, by means of a feed device 30 to the entrance of the cutting path 36, on which an automatic bundle cutting unit 33 designed as a cross cutting unit is installed. At the entrance of this cutting section 36, all six strip layers 18 belonging to one and the same sheet stack S5 are collected in a defined starting position P2, in which the edges trimmed in the longitudinal cutting device 25 are aligned by abutment against a stop which is formed by the slide system 31 of the feed direction 32 . While previously known installations provide a single feed device with a slide which is common to all the strip layers, the feed device 32 according to the invention, as will be explained later, consists of a number of individual feed devices corresponding to the number of strip layers 18 per stack with slides individually moving the strip layers . All six strip layers 18 belonging to a sheet stack, which, as indicated in FIG. 1, are arranged next to each other at a small distance, are then moved together by means of the feed device 32 in the direction of arrow F2 to the bundle cutting device 33, wherein they are guided in grooves. In the bundle cutter 33, the front edge of all the strip layers 18 corresponding to the sheet side edge 17 (FIG. 2) is first trimmed and then all six strip layers 18 are gradually cut simultaneously into three bundles of notes 19, which are already banded and in which the notes of value are finished Format. In these feeds, the trimmed rear edges form the reference edges which are decisive for the bundle cut and against which the slides of the feed device 32 rest.

The processing of note sheets into banded note bundles as well as the cutting and banding machines used for this purpose are known and are described, for example, in Swiss Patent CH 612 639 and US Patent No. 4,283,902 by the same applicant, as well as in the older German patent application DE -A-3 238 994 (published May 5, 83) by the same applicant.

The banded bundles 19 cut to format are advanced to a transport path 37 and arrive at further processing stations which are not of interest here, in which bundle packages with consecutively numbered notes of a particular series are formed and these bundle packages are then banded and packaged. This further processing is the subject of, for example, the Swiss patent specification CH 577 426 and the American patent specifications US 3939621 and 4,045,944 by the same applicant.

In addition to the use of individual feed devices for feeding the individual strip layers, in the cutting machine described here with reference to FIG. 1, there is a further difference from the known prior art in that, for reasons which will be explained later, only one longitudinal cutting device 25 for trimming the edge of one side edge of the Bo gene is provided and the edge trimming takes place on the opposite sides only in the bundle cutter, while it is known and customary to provide two opposite longitudinal cutters instead of a slitter in front of the strip cutter 27, which cut each stack to size on both opposite side edges simultaneously.

• - der Abstand D = D_o zwischen der Anfangsposition P1 eines Stapels und derjenigen Stapelposition im Streifenschneidwerk 27, in welcher der Vorderrandbeschnitt erfolgt;
• - die zwischen aufeinanderfolgenden Streifenschnitten erfolgenden Vorschubschritte, welche gleich der Breite a eines Wertscheins 12 sind;
• - der Abstand E = Eo zwischen der Anfangsposition P2 der Streifenlagen 18 und deren Position im Bündelschneidwerk 37, in welcher der erwähnte Randbeschnitt der Vorderränder der Streifenlagen stattfindet und
• - die zwischen aufeinanderfolgenden Bündelschnitten erfolgenden Vorschubschritte, welche jeweils die Länge b eines Wertscheins 12 haben.

So far, all feed lengths or feed steps, which determine the exact cutting lines for strip cutting and bundle cutting, have been set once and for all for the type of sheet being processed and will be fixed to those before the start of the processing operations depending on the given sheet and note format and the number of sheets automatic feed devices are set, which are electronically programmable for this purpose. These fixed values include:

• the distance D = D _o between the starting position P1 of a stack and that stack position in the strip cutting unit 27 in which the front edge trimming takes place;
• the feed steps taking place between successive strip cuts, which are equal to the width a of a note 12;
• - The distance E = Eo between the initial position P2 of the strip layers 18 and their position in the bundle cutter 37, in which the mentioned edge trimming of the front edges of the strip layers takes place and
• - The feed steps taking place between successive bundle cuts, each of which has the length b of a note 12.

According to the definitions D = Do - d and E = Eo - e given in FIG. 1, the specified distances have the fixed values D = D _o and E = as long as the corrections d and e discussed later are zero or are not taken into account Eo.

According to the present invention, as long as the engraving printing plates used are new and have not undergone any significant expansion, the originally set, constant feeds D _o , a, E _o , and b are used. As long as there is no noticeable stretching of the engraving printing plates, the outline 11 of the overall printing image (including the later value edges) shown in FIG. 2 is, of course, exactly rectangular, corresponding to the exact original geometry and arrangement of the engraving pits of the printing plates, and that in FIG. 2 is also rectangular Security impressions 13 shown are all undistorted and of the same size and are always centered after the sheet 10 has been cut into security notes 12 with the same format axb along the dashed cut line, always centered with respect to the unprinted value border.

In the course of operation, the printing plates now expand under the action of the contact forces which are exerted by the printing cylinder during each printing process. This deformation is particularly strong in the case of an engraving printing plate, since a particularly high pressure must be used in steel engraving printing. With this printing plate deformation, the lengthening and widening takes place in a non-linear manner, so that the printing surface assumes an approximately trapezoidal shape, the rear printing plate edge as seen in the direction of rotation of the plate cylinder forming the base side of the trapezoid. Accordingly, the outline 11 ', which delimits the area of the total printed image of all the security impressions of a sheet 10 and is shown in broken lines in FIG. 2, and each individual security impression are distorted approximately in a trapezoidal shape.

In the example according to FIG. 2, the total print image in direction F1 is extended by the amount d compared to its original dimension, which was 6a.

A sheet 10, the print image of which is distorted and has the outline 11 ', is shown in FIG. 3. In addition, those lines are drawn in dashed lines in FIG. 3 which would have to form the cut lines in the later strip and bundle cut, so that despite the distortion in all manufactured notes, the security impressions (not shown in FIG. 3) are at least approximately in the mirror, i. H. are centered in relation to the unprinted value border.

The feed control described below with varying feed lengths according to the invention now makes it possible to cut each sheet along these “target cutting lines”, which thus define the corrected dimensions of the notes of value.

In the example according to FIG. 3, an expansion state of the printing plate is assumed, in which the dimensions of the individual rows of notes 6 to 1 gradually increase in the direction of F1. Thus, the width of the value row 6 adjacent to the gripper edge 14 has increased from the original value a by an amount x to the value a + x, that of the value row 5 to the value a + 2x and that of the following value rows 4 to 1 to the values a + 3x, a + 4x, a + 5x and a + 6x enlarged. The total extension in the direction of F1 is therefore 21x, which is equal to the amount d shown in FIG. 2. Of course, in practice, these extensions do not exactly have to be integer multiples of the increase x of the least distorted value series 6, as was assumed here as an example for the sake of simplicity.

The dimensions of the individual blanks oriented in the direction of F2, that is to say parallel to the gripper edge 14 (that is to say the security impressions including their unprinted border) take along each of the rows of tokens 1 to 6, starting with one compared to the original one Dimension b increased value, first from time to time and then further and from row of banknotes to banknotes, viewed in direction F1, successively larger. In the example under consideration, the individual benefits located at the ends of the value row 6 have a dimension b + y enlarged by the amount y, while the two middle individual benefits are only extended to b + 0.5. In the value row 5, the two individual uses at the ends have the dimension b + 2y and the two middle ones have the dimension b + y. In the value row 4, the two individual uses at the ends have the dimension b + 3y and the two middle ones have the dimension b + 1.5y. In the following value series 3, 2 and 1, the outer individual uses have the dimensions b + 4y, b + 5y and b + 6y and the middle ones have the dimensions b + 2y, b + 2.5y and b + 3y.

With a sheet size of 500 x 750 mm, for example, the values x and y after 100,000 prints can be, for example, approximately 0.05 mm each, so that the extension d of the total printed image of a sheet (FIG. 1) is approximately 1 mm. If the sheet stacks are cut as before with constant feed lengths, i.e. along the dashed lines in FIG. 1, then the printed image 13 of the banknotes 12 is practically still centered within the row of banknotes 6 within the unprinted banknotes border, but all others point Notes have a more or less shifted print image from their central position, whereby these centering errors are greatest for the notes of the value series 1 and of course become stronger and more conspicuous with an increasing number of prints.

In order to avoid these centering errors, the individual feed lengths are now changed in accordance with the distortion values discussed above, both in the case of a strip cut in the direction of F1 and in the case of a bundle cut in the direction of F2.

First, the correction for the strip cut should be considered. In order to realize a fully automatic control of the feed varying during strip cutting, according to a first preferred embodiment of the method according to the invention, pressure markings are provided on the engraving printing plate, which define the later cutting lines and inevitably change their position as the printing plate expands. When the sheets 10 are printed in the engraving printing unit 20, these markings are also printed on one side edge 17 of each sheet and, in the example considered (FIGS. 2 and 3), consist of line-shaped markings m which are assigned to the cutting line parallel to the gripper edge 14. These markings are read immediately before the sheet stacks enter the strip cutting unit 27 by a reading device 28 (FIG. 1), which brings the sheet stacks to a standstill in the intended cutting position.

The distance of the reader 28 from the knife of the strip cutter 27 and the positions of the markings m relative to the cutting lines assigned to them are selected such that after the feed device 26 has been switched off when the reader 28 is activated, a sheet stack arises due to its inertia and the inertia of the Feed mechanism just moved into the desired cutting position and comes to a standstill there. This braking distance or run-out distance of a stack is a defined size that can be reproduced exactly for the same stack. Thus, the first marking m in feed direction F1 ensures that a stack automatically travels exactly the feed length D = D _o - d, d increasing with increasing printing plate expansion, so that the width of the front edge 16 of the sheet cut off in the first cut in the Becomes correspondingly smaller in the course of operation. The following markings m precisely control the sequence of the progressively smaller feed steps, in the example according to FIG. 3 the feed steps a + 6x, a + 5x, etc. to a + x.

The easy-to-implement markings to be printed and their automatic reading by a reading device 28 controlling the feed device 25 therefore permit constant exact control of the feed lengths when cutting strips as a function of the constantly increasing pressure plate deformation. When the cutting operations in the cutting machine are carried out, it is only necessary to ensure that the side edge 17 of the sheet having the markings m is cut off only after the strip cuts, which is done in the bundle cutter 33 in the example considered by the front edge trimming.

Instead of individual markings, double markings can also be provided, which, as indicated in FIG. 3, consist of two line-shaped markings m _s and m located at a short distance from one another. The arrangement is then such that when the first mark m _{s is} read, the normal feed speed of the sheet stacks is reduced to a creeping movement and the feed device is only switched off when the second mark m is read. The preceding braking of the sheet stacks before they are stopped in this way increases the running accuracy into the cutting position and is expedient when the sheet stacks are pushed forward in the usual way, as described, by means of sliders which only abut the rear edge of the stack.

The control of the feed in the bundle cut as a function of the increasing printing plate expansion is now somewhat more complicated than in the case of strip cutting, because not only the four individual benefits belonging to a bank note series within a strip position are of different lengths, but also become longer within a group of the six strip layers belonging to the stack in the direction F1 from strip layer to strip layer, as has already been explained with reference to FIG. Therefore, the feed paths of the individual strip layers 18 must be different when they are simultaneously fed to the bundle cutter 33 and between the subsequent bundle cuts. In order to achieve this, the feed device 32, as indicated schematically in FIG. 4, consists of a number of separate, independently controllable feed devices 321 to 326 corresponding to the number of strip layers per stack, each of which, with its associated slide 311 to 316, is one of the Strip layers 18, which correspond to the value rows 1 to 6, moved individually. These sliders 311 to 316 thus replace the previously known slider common to all strip layers and form the slider system 31 mentioned in the description of FIG. 1.

Since, in the example under consideration, the rear edges of the strip layers 18 are already trimmed to their final format when the side edge is trimmed in the slitter 25, this side edge trimming is not always carried out exactly at a right angle to the gripper edge 14 (FIG. 1), but rather along the side boundary 15 Line of the trapezoidal outline 11 'of the overall printed image; this line of intersection includes the angle a with the gripper edge 14 (FIG. 3), which becomes greater than 90 ° with the onset of distortion and increases with increasing pressure plate expansion. For this purpose, the longitudinal cutting device 25 or its knife can be rotated about a vertical axis in such a way that the cutting angle tt relative to the gripper edge 14, starting from an originally right angle, can be made ever larger during operation. Corresponding to this cutting angle α, the slides 311 to 316 of the feed devices 321 to 326 are also set more and more obliquely in the course of operation, so that they are always oriented parallel to the rear edge of the strip layers 18 and thus lie snugly against them in order to ensure a well-defined feed. For this purpose, the slides 311 to 316 can be pivoted about vertical axes within a sufficient angle.

Different possibilities of how this cutting angle ex of the slitter 25 can be controlled automatically will be explained later; At this point it is assumed that the cutting angle is changed as a function of the increasing distortion, as explained, which in the simplest case can be carried out by hand in such a way that after the passage of, for example, 50,000 to 100,000 sheets each, corresponding to 500 to 1000 stacks with 100 sheets each, based on a visual inspection and measurement of the printed images or the stretched printing plate.

In order to control the advance of the strip layers 18 in the bundle cuts, no special printing markings can generally be used now, because these should not be printed on laterally cut off edge strips, but in the value note areas, which is generally not accepted. Only the first cut position for the front edge trimming of the strip layers could be defined by markings which, like the markings m for the strip cut, are applied to the sheet edge 17. For this reason, according to a first, preferred embodiment of the method according to the invention, it is provided to select a characteristic position on the respective security note which is located in the vicinity of the cutting line to be realized and to which a reader responds selectively in each case. This can be a local pattern, a certain color range or a striking contrast, preferably the contrast between the light, unprinted value border and a dark area of the value print. Such a characteristic point, in particular a sufficient contrast at the limit of the printed value of the banknote, can be found practically on all banknotes and can be used as a natural marking selectively recognizable by a reading device, which defines the adjacent cutting line. With the high level of development of photoelectric devices, readers with the required selectivity are readily available or are easily adaptable. In order to ensure the unambiguity of the reading, reading windows can be used in a known manner, as is done, for example, when reading register marks in printing machines. The characteristic locations to be read for controlling the feeds can also be fluorescence areas provided on the bill of value. Furthermore, these characteristic points can also be non-optical properties, for example metal threads or the like embedded in the note paper, to which suitable detectors respond.

It is assumed that the mark for the feed control during the bundle cut is the contrast between the light value note border lying in the direction of F2 and the dark printed image of each individual use on each of the strip layers 18. To detect these contrasts, a reader system 34 with the six readers 341 to 346 (FIG. 4) is installed in front of the bundle cutter 33, which individually scan the individual strip layers 18, corresponding to the six rows of notes 1 to 6, and the feed devices 321 that move these strip layers control up to 326 individually. Starting from the aligned starting position P2, the six strip layers 18 are advanced together, which are of different lengths on their rear edges because of the somewhat oblique edge trim, as illustrated in FIG. 4.

Because of this different length and because of the distortion of the printed image, the reader 341 first responds to the first contrast point of the strip position corresponding to the bank note row 1, that is to say to the front boundary of the first printed security image, and therefore switches off the feed device 321. The arrangement is such that the strip position then comes to a standstill after a total feed length E1 in the first desired cutting position, in which the front edge of the strip layer is trimmed. The feed lengths of the remaining strip positions which correspond to the value note rows 2 to 6 and which are correspondingly controlled by the readers 342 to 346, increase successively and are designated in FIG. 4 by E2, E3, E4, E5 and E6. In general, E = E _o - e _i applies, whereby the index i refers to one of the six value series 1 to 6 and can accordingly assume the values 1 to 6. For i = 1, that is to say the strip position corresponding to the bank note series 1, in the example considered according to FIG. 3, ei = 18y, e2 = 15y, e3 = 12y, e ₄ = 9y, es = 6y and e ₆ = 3y.

Only when all six strip layers 18 have assumed their desired cutting position is the simultaneous front edge trimming carried out in the bundle cutting device 33. The subsequent successive feed steps are then controlled individually by the reading devices for each strip layer so that they have the lengths indicated in FIG. 3 and already discussed, namely the lengths b + 6y, b + 3y and b + 6y for the strip position corresponding to the value row 1; for the other strip positions corresponding to the value series 2 to 6, the lengths of these feed steps then decrease, as indicated. Again, of course, the common bundle cuts only take place when all the strip positions have completed their individual feed steps and have come to a standstill in their desired cutting position. All cut lines are indicated by dash-dotted lines on the strip layers 18 in FIG. 4.

In this way, all the banknotes 33 leaving the bundle cutter 33 have an at least approximately mirror image and edges perpendicular to one another, with the exception of the last banknotes of the strip layers 18, whose rear edges in the direction F2, for the reasons explained earlier, in the event of greater elongations of the printing plate run somewhat obliquely, but this can easily be accepted, since this small error, which is only noticeable on closer inspection, is much less noticeable than the centering errors of the printed image that have been accepted so far. Therefore, the effort of a further edge trimming of these rear edges is not worthwhile, especially since for technical reasons such an edge trimming is generally only flawlessly possible if the waste strip has a width of at least about 2 mm.

In order to also automatically control the previously mentioned cutting angle α for the slitter 25, it is necessary to measure a variable characteristic of the stretching condition of the overall print image 11 ', for example the length of the boundary of this overall print image 11' adjacent to the sheet edge 16. As can be readily seen, the angle x entered in FIG. 3 increases with increasing length of this print image limitation according to a relationship which can be determined theoretically and / or empirically for a given type of printing plate. To measure these dimensions of the total printed image, which in the example under consideration are approximately 4b + 18y, a measuring device 351, indicated schematically in FIG. 6, can be provided on the feed device 321, which measures the sum of the four feed steps covered in the bundle cuts of the strip position ; this sum, 4b + 18y in the example under consideration, corresponds precisely to the required length dimension, from which the cutting angle α can be derived on the basis of the relationship mentioned. The measured value supplied by the measuring device 351 is therefore fed to a suitably programmed mini-computer or microprocessor, which calculates the associated value of the angle, x and issues a control command for correspondingly controlling the cutting position of the longitudinal cutting device 25. Of course, other methods for measuring the respective distortion state of the overall printed image 11 'and for automatically evaluating the measurement results for the purpose of controlling the desired cutting angle are also possible.

According to a second embodiment of the method for feed control in the bundle cut, reading devices are dispensed with and the control is carried out with the aid of a mini computer or microprocessor, depending on the feed values covered in each case in the strip cut. Use is made of the theoretically and / empirically determinable relationship that exists between the elongation in the longitudinal direction and the transverse direction for a given printing plate. If a characteristic strain value in the direction of F1 (FIG. 3) is known, then the corresponding strain in the direction of F2 can be calculated on the basis of this relationship, or at least can be estimated with sufficient accuracy for the present purposes. A measuring device 36, which is indicated schematically in FIG. 1, is then required, which is attached to the feed device 26 and in each case measures one or more of the feed paths covered by this feed device during the strip cutting of a stack of sheets, as has already been explained for the measuring device 351 of the feed device 321. For example, it is sufficient to measure only the feed length D = Do - d and thus the increasing change in length d of the sheets 10 and into the appropriately programmed mini-computer or microprocessor enter, which calculates from it all control commands that are required for the already discussed, individual feed control of the individual strip positions of the sheet stack in question in the bundle cut. This second embodiment requires only a reader 28 for reading the markings defining the strip cuts and for controlling the strip cutting unit 27, as well as a correspondingly programmed mini-computer or microprocessor, to which the measured feed lengths of the feed device 26 are entered as measured values and which controls the described individual feeds for the bundle cut; at the same time, in this case, he preferably also controls the setting of the longitudinal cutting unit 25 to the respective cutting angle a, which also results from the relationship or programming mentioned.

If the feed devices expediently consist of the linear amplifiers mentioned in the introduction, then the measuring device for measuring the feed paths covered can simply consist of a rev counter, which measures the number of revolutions carried out by the stepper motor mentioned. In principle, of course, a feed path covered by the feed device can also be determined in another way, for example optically by measuring the distance covered by a sheet stack or a strip position.

According to a third embodiment of the method, it is also possible to dispense with printing markings and readers in such a way that all feeds, both in the case of strip cutting and bundle cutting, are controlled by a computer which has been given a program which detects the increasing elongation of the printing plate in question as a function of Describes the number of prints. The course of the expansion of a particular Druckpla _t tentyps with the number of prints can be performed mathematically and / or empirically determined or based on experience and establish therefrom a complete program for the feed control.

According to a fourth embodiment, the simplest procedure is that the programmable feed devices 26 and 32 are initially set in the usual way to the constant original feed values D _o , a, E _o and b and are always re-programmed by hand in the course of operation as soon as the centering error that arises becomes noticeable to the naked eye or begins to become disruptive. For example, after 100,000 prints, that is to say after the passage of 1000 stacks with 100 sheets each, the originally set feed values can be changed by the correction values x or y discussed in detail with reference to FIGS. 2 to 4, for example x = y = 0.05 mm is selected; this then results in the other correction values d of approximately 1 mm and the various e _i corrections. Such changes in the feed programming by modifying the correction variables x and y are then repeated several times by hand with increasing deformation of the printing plate until the service life of the printing plate is exhausted. In general, the number of prints, after which the correction values mentioned are changed by the step of 0.05 mm considered here, will of course not be constant, but rather as a function of the expansion of the printing plate, which usually does not increase linearly with the number of prints to get voted. The values of the correction values to be introduced in each case can either be determined in advance from the theoretically or empirically known course of the printing plate expansion or, on a case-by-case basis, by inspecting and measuring the stretched printing plate or the distorted outline of the overall print image of a sheet.

In general, the distortion effects produced by the printing plate stretching in the transverse direction are less disturbing than those in the longitudinal direction (direction F _o ), because namely the widening in the transverse direction takes place symmetrically on both sides and therefore the security impressions in the central region of the sheets are only relatively slight after the one and shifted to the other side and the laterally outer security prints experience a shift that only corresponds to approximately half of the overall widening of the overall printed image 11 '. In contrast, the distortion effects add up in the individual value rows 6 to 1 of a sheet in the longitudinal direction, that is to say in the direction F1, as the example according to FIGS. 2 and 3 illustrates. For this reason, it may be sufficient to apply the feedrate correction described only for strip cutting and, as usual, to work with constant feed rates for bundle cutting.

Of course, the correction options described above for the strip cut and for the bundle cut can also be combined in any way, for example in such a way that the feed control takes place fully automatically during the strip cut, while the feed program for the bundle cut is changed by hand as required. In general, it must also be taken into account that the accuracy of the centering of the security prints within their border not only depends on the printing plate stretching, but is subject to more or less large tolerances, which essentially depend on differences in the format of the note sheets, on the pressing and stretching of the paper during printing and come from its moisture content and from inaccuracies when cutting. It would therefore be useless to introduce feed corrections that are more precise than the tolerances mentioned, to which the centering of the security notes is subject for other reasons.

The examples described above be affected the cutting of the sheets and layers of strips by individual cuts, which has the consequence that because of the different feed steps, the format of the generated notes of value is not constant, but varies to a small extent. However, this somewhat different format of the note is practically insignificant and is acceptable in most cases.

However, with the method according to the invention, it is also readily possible to produce notes of constant format if one works with intermediate cuts in a manner known per se. A related embodiment is explained with reference to FIGS. 5 and 6. 5 shows a bill of value 110 with 16 individual bills 112, which are arranged in four rows of bills 101 to 104 of four individual bills each. It is assumed that the engraving printing plate, which has printed this sheet, has undergone a noticeable stretching, as in the example according to FIGS. 2 and 3, so that the outline 111 'of the total printed image of all security impressions 113 is again distorted approximately trapezoidally.

Those later cut lines which, despite this distortion, ensure an approximate centering of the security impressions 113 within their borders, are drawn in with dashed lines and selected so that the format of all security notes 112 is always exactly the same size and has the dimensions a times b. For this, the widths of the intermediate strips between the individual panels vary, which are later cut off as waste strips. The width of the intermediate strips Z1, Z2 and Z3 lying between adjacent value note rows 101 to 104 decreases exactly in the direction towards the gripper edge 114 of the sheet, as was explained in the example according to FIGS. 2 and 3 for the feed steps in the strip cutting . If the original width of all the intermediate strips Z1 to Z3 had the value f, then the widths in the example considered according to FIG. 5 are now f + 3x, f + 2x and f + x. The intermediate strips lying between adjacent individual uses of each banknote row, which are designated in FIG. 5 for banknote row 101 with Z11, Z12 and Z13 and for banknote row 104 with Z41, Z42 and Z43, change individually and in each banknote row differently in an analogous manner as the feed steps of the individual strip layers in the bundle cuts described using the example of FIGS. 3 and 4. When cutting a stack with the sheets 110, both the strip cutter 27 and the bundle cutter 33 are controlled in such a way that those feeds which define the cutting lines in a waste cut (i.e. when cutting the front edge or an intermediate strip) depend on the pressure plate expansion , as described, are changed, while the other feeds, which define the cutting lines when cutting the strip layers or the individual bundles of notes, are programmed as fixed values and are always a or b according to the desired note format.

For automatic control of the feed, in the example according to FIG. 5, on the one hand, print markings m are provided on the side edge 117, which are read by the reader 28 for feed control during strip cutting, and on the other hand print markings n, which are printed on the intermediate strip between adjacent individual uses of each row of notes and can be read from the readers 341 to 344 (FIG. 6) for the purpose of feed control during the bundle cut of the individual strip layers 118. All printing markings m and n define the widths of the front edges and intermediate strips to be cut, which are variable as a result of the printing plate expansion.

With a machine shown in FIG. 1, after the side edge 115 has been trimmed, as described earlier, the front edge 116 is first cut off in the strip cutter 27, the feed into this cutting position being controlled by the reading device 28 by reading the first pressure marking m . The length a of the following feed step into the cutting position required for the first strip cut is pre-programmed. The feed into the following sectional position, in which the intermediate strip Z1 is cut off, is in turn controlled by the reading device 28 by reading the second print mark m. This is followed by a feed step of length a, and so on.

The feed device 32 for the four strip layers (118) belonging to a stack again comprises feed devices 321 to 324 individually assigned to these strip layers with their slides 311 to 314. The feed from the aligned starting position P2 into the first cutting position, in which the front edges of the strip layers 118 are cut off, the readers 341 to 344 control the reading of the printing mark located on the front edges n of each strip position individually for each strip position. After the edge trimming, each of the feed devices 321 to 324 carries out a permanently programmed feed step of length b, whereupon the foremost bundles of notes of each strip layer are cut off. The next feed is in turn controlled by the reading devices, individually for each strip position, when reading the respective marking n on the intermediate strips Z11, Z21, Z31 and Z41, whereupon these strip layers are cut off together. This cut is followed by a programmed feed step of length b, etc.

In this way, one obtains vouchers whose voucher impression is always at least approximately centered and which all have the same format, if one disregards the small inaccuracy that occurs for the last bundle of vouchers as a result of the Bundle of notes of the strip layers results from the side edge trimming in the slitter 25.

The processing of sheets of notes described above with the aid of intermediate cuts generally presupposes that the waste strips produced are at least 2 mm wide in order to ensure flawless cuts.

Dispensing with the special print markings m and n and reading devices, the described feed control when working with intermediate cuts can also be carried out either according to a prepared program that changes as a function of the printing plate expansion or by hand, as is the case for the example according to FIGS. 2 to 4 has been described. In the case of feed control by reading devices, it is also possible, without special printing markings m and n, to use characteristic points of the individual use that are selectively recognizable by the reading devices as natural markings, in particular the contrast at the boundary of the security print, as explained earlier.

The method according to the invention can also be applied to sheets of notes in which the strip cuts are made with individual cuts, whereas the bundle cuts are made with intermediate cuts. In this case, it is possible to work with pressure markings m for the strip cut and with pressure markings n for the bundle cuts, it being ensured that the dimension b of the note format remains constant.

The invention is not restricted to the exemplary embodiments described, but rather permits numerous variants. In principle, if the side edge 17 of the sheet has no pressure markings m for feed control during the strip cut, both opposite side edges of the sheet stack can be trimmed simultaneously on the cutting section 24 before the strip cuts are carried out. Furthermore, the strip layers belonging to a sheet stack can be divided into bundles of notes one after the other in time, the feed steps being successively changed individually for each strip layer.

Claims (16)

1. Method for the manufacture of freshly printed security paper (12) cut to format, according to which sheets (10) of security papers with security paper imprints (13) arranged in the form of a matrix are printed and laid one on the other to form piles (S) and the piles (S5) of sheets formed in this way are cut with a step-wise feed automatically first of all into layers (18) of strips and these layers of strips are then cut into bundles (19) of security papers, characterised in than when cutting the strips and/or when cutting the bundles, the lengths of the feed movements between successive strip cuts or bundle cuts are varied individually depending on the increasing expansion of the printing plate of the sheet- printing machine (20) so that the printed image of the security papers cut to format at least approximately maintains its exact centering with respect to the edge of the security paper.

2. Method according to claim 1, characterised in that one works with intermediate cuts at least when cutting bundles and solely the length of the feed steps, which determine the size of the waste strips (Z), is varied depending on the increasing expansion of the printing plates, whereas the length of the feed steps, which determine the format of the security papers at least when cutting bundles, always remains constant.

3. Method according to claim 1 or 2, characterised in that the strip cuts take place parallel to the gripper edge (14) of the sheets (10), in which case the gripper edge is located at the rear in the feed direction, that the length of the feed (D) of a pile of sheets (S) from a given initial position (P1), in which its gripper edges are aligned, into that position in which the trimming of the front edges takes place in the strip-cutting unit, is reduced (Do - d) with respect to the initial value (Do) corresponding to the undeformed printing plate, as the expansion of the printing plate increases, and that the respective first feed steps, which determine the width of the first layer of strips or of the first waste strip produced with intermediate cuts, when cutting the pile of sheets, are increased with respect to the initial value corresponding to the undeformed printing plate, when the expansion of the printing plate increases, and the remaining feed steps, which determine the widths of the following layers (18) of strips or waste strips (Z), when cutting a pile (S) of sheets, are successively reduced in comparison to the respective first feed step.

4. Method according to any of claims 1 to 3, characterised in that the bundle cuts take place at right angles to the gripper edge (14) and that the respective first feed steps, which determine the dimensions, seen in the feed direction of the first bundle of security papers or of the first waste strips (Z) produced with intermediate cuts, when cutting the layers of strips, are increased with respect to the initial value corresponding to the undeformed printing plate, as the expansion of the printing plate increases, and the remaining feed steps, which when cutting a layer (18) of strips determine the dimensions of the following bundles (19) of security papers or waste strips (Z), at first are reduced in comparison to the first feed step as far as cuts in the central region of a layer (18) of strips and then are once more increased, in which case for all layers (18) of strips belonging to one and the same pile (S) of sheets, the feed steps corresponding to one another are chosen to be all the greater, the further the respective layer of strips is located from the layer of strips adjacent the gripper edge.

5. Method according to claim 4, characterised in that before cutting the bundles, a side edge (15) of the sheets (10) or of the layers (18) of strips orientated at right angles to the gripper edge (14) is cut along a cutting line, which extends at least approximately parallel to the adjacent lateral boundary of the total printed image on the sheet and therefore with increasing expansion of the printing plate encloses with the gripper edge an angle ancreasing beyond 90° and that the length of the feed of the layer of strips from a given initial position, which is defined by the position and alignment of the afore-mentioned cut side edges, to that position in which the trimming of the front edge (17) of the layer (18) of strips in the bundle-cutting unit (33) takes place, is reduced with regard to the initial value corresponding to the undeformed printing plate, as the expansion of the printing plate increases, in which case for all layers (18) of strips belonging to one and the same pile (S) of sheets, the afore-mentioned feed length is chosen to be all the smaller, the further the respective layer of strips is located from the layer of strips adjacent the gripper edge.

6. Method according to claim 5, in which all layers (18) of strips belonging to one and the same pile (5) of sheets are assembled one beside the other in their initial position (P2), moved forwards jointly to the bundle-cutting unit (33) and cut simultaneously at this point step-wise into bundles (19) of security papers, characterised in that the feed length to the bundle-cutting unit (33) and the individual feed steps when cutting bundles are adjustable and controllable separately and in a different manner for each individual layer (18) of strips.

7. Method according to any of claims 1 to 6, characterised in that the length of the feed movements are re-adjusted by hand respectively after the passage of a certain number of piles (S) of sheets.

8. Method according to any of claims 1 to 6, characterised in that the lengths of the feed movements can be controlled by means of a computer on the basis of a programme adapted to the increasing expansion of the printing plate.

9. Method according to any of claims 1 to 6, characterised in that at least one side edge (17) of the sheets (10) orientated parallel to the feed direction (F1) of the pile (S) of sheets, when cutting strips, which is cut off at the time of a subsequent trimming, is printed with edge marks (m) provided on the printing plate, during printing of the sheets, which marks (m) define the position of subsequent strip cuts or waste cuts, and that the length of the feed movement producing guidance into these cutting positions is controlled automatically as a function of these edge marks (m) read by a reading unit (28, 34).

10. Method according to any of claims 7 to 9, characterised in that the lengths of the variable feed movements carried out when cutting strips, are measured automatically and stored in a computer and that at the time of subsequent cutting of bundles from the respective layers (18) of strips, the feed lengths to be varied are controlled automatically as a function of these stored values on the basis of a programme fed into the computer, which forms a relationship between the expansion of the printing plate in the longitudinal direction and the expansion in the transverse direction.

11. Method according to claim 2 or 9, characterised in that one works with intermediate cuts at least when cutting bundles, and during printing of the sheets (10), those regions which are cut off as waste strips (Z) at the time of the subsequent intermediate cuts, are printed with marks (n) located on the printing plate, which marks (n) define the position of the subsequent intermediate cuts, and that the lengths of the feed movements, which determine the width of the waste strips, are controlled automatically as a function of these marks (n) read by reading units (34).

12. Method according to claim 9 or 11, characterised in that two individual marks per cutting line are applied as edge marks (m) or marks (n) to the subsequent waste strips (Z), and that reading of the first individual mark in the feed direction brings about a reduction of the normal feeding speed to a creeping movement and reading of the second individual marks stops the feed movement.

13. Method according to any of claims 1 to 6, characterised in that the lengths of the feed movements to be varied can be controlled by detectors (28, 34), which respond to similar, selected characteristic points in each security paper imprint, such as patterns, coloured marks or contrasts, in particular to the contrast between the light border of the security paper and a dark region of the security paper imprint.

14. Automatic cutting machine for carrying out the method according to claim 1, with strip and bundle-cutting units (27, 33) and with feed devices (26, 32) for the piles of sheets and layers of strips, associated with these cutting units, operating automatically and which can be adjusted, in particular with linear amplifiers, which comprise a hydraulic cylinder with the supply of pressure medium metered by a stepping motor, characterised in that when cutting a pile of sheets and possibly when cutting a layer of strips, the feed movements of the feed devices (26, 32) can be varied individually from step and can be controlled as a function of a predetermined programme or by reading units (28, 34), which respond to printed marks (m, n) on the sheet or to characteristic points of the security paper imprints (13).

15. Cutting machine according to claim 14 with a bundle-cutting unit (33), to which all layers (18) of strips belonging to one and the same pile (S) of sheet are supplied jointly by moving on the longitudinal direction and in which these layers of strips are cut simultaneously into bundles (19) of security papers, characterised in that associated with all the afore-mentioned layers (18, 118) of strips is an individual feed device (321 to 326) which can be controlled separately from the others.

16. Cutting machine according to claim 14 or 15, characterised in that a cutting unit (25) is provided for trimming the edge (15) of the sheet which during the feed movement of the layers (18) of strip, when cutting bundles, forms the rear edge, and that both the cutting direction of this cutting unit (25) as well as the orientation of the slides (311 to 316) belonging to the afore-mentioned feed devices (312 to 326), which act on this cut edge of the layers (18) of strips and move it forwards at the time of cutting bundles, can be varied as a function of the increasing expansion of the printing plate.

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