EP0091713A1 - Method of making ready printed, numbered and cut to size bank notes, and automatic cutting machine for carrying out the method - Google Patents

Abstract

Sheet stacks (S5) of note sheets (10), which have security impressions arranged in the form of a matrix, are automatically cut into strip layers (18) and then into bundles of notes (19) with gradual feed. The lengths of the feed movements of the feed device (26), which feed the sheet stacks step by step during the strip cutting, are controlled by a reading device (28) provided on the strip cutting unit (27) each time an edge marking is read, since these markings provided on the printing plate inevitably occur during operation With increasing printing plate expansion, automatic control of the feeds between successive cuts is achieved in such a way that the centering of the printed image on the notes of value relative to the unprinted edge of the note is maintained much more precisely than has been the case in spite of the increasing printing plate expansion.

Description

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

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 impressions arranged in a matrix, are generally produced, 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 in each case based on a feed program that has been set once, depending on the size of the banknotes or the desired note format. The resulting cut-out notes 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.

_N ow but it is desirable for aesthetic reasons and also for reasons of security against counterfeiting, that the image is always centered, always is a value within the bill banknote borders or, as they say exactly 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 experience a gradual expansion under the action of these forces during operation, that is to say become increasingly longer and also wider, this widening becoming greater 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. The length and widening of the printing plate change the size and position of the prints, so that the automatic stacking of sheets is done with constant feed lengths cut notes of value arise, in which the printed image moves more and more from 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 receipts to be obtained when cutting the stack of sheets, which have at least approximately centered printed images with respect to the value edges.

This object is achieved by the in the characterizing part of claim 1 and, with regard to the cutting machine for performing the _e r inventive method, solved by the features specified in claim 15.

The _A enderung the feed lengths may be performed in the simplest case by hand due to an experience of the program that was empirically for the relevant printing plates, optionally also positioned and theoretically. One then begins to readjust the feed lengths as soon as the deformation of the printing plate assumes a dimension that is disruptive in practice, which can be the case, for example, after 50,000-100,000 prints. After a further 50,000-100,000 prints, the lengths of the feed movements can then be changed and adjusted accordingly. The readjustments to be made to the original feed program can also be made on the basis of 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 as linear amplifiers. These linear amplifiers have a hydraulic cylinder-piston system, whereby the metered pressure medium supply of the hydraulic cylinder takes place with the aid of a stepper motor which briefly opens the pressure medium inlet valve with each revolution; as a result, with one revolution of the stepper motor, a precisely metered, small amount of pressure medium is supplied to the cylinder such 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 machine can be automatically controlled as a function of the positions of these print markings in such a way that notes of value 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 you do not make intermediate cuts, the size of the finished cut notes of value varies slightly 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 valued much higher than the somewhat different size of the notes of value. 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 they are processed into packaged bundle packages. In contrast, an incorrectly centered printed image immediately notices the viewer of a note.

If, however, 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 bundle 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 worked with fixed feed lengths.

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

• Figur 1 die schematische Ansicht der wesentlichen Verarbeitungsstationen bei der Fertigung von Wertscheinen gemäss der vorliegenden Erfindung,
• Figur 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,
• Figur 3 den Bogen nach Figur 2 mit dem verzerrten Gesamtdruckbild und den strichpunktiert angedeuteten, späteren Schnittlinien, deren Lagen aufgrund der _Aenderungen der Vorschublängen korrigiert sind,
• Figur 4 den das Bündelschneidwerk nach Figur 1 einschliessenden Bereich mit den sechs Streifenlagen in schematischer, vergrösserter Darstellung mit den zugeordneten Vorschubeinrichtungen,
• Figur 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
• Figur 6 eine der Figur 4 entsprechende Darstellung, welche den Vorschub der vier Streifenlagen des Bogens nach Figur 5 beim Bündelschnitt veranschaulicht.

The invention is explained in more detail with reference to the drawings. Show it:

• 1 shows the schematic view of the essential processing stations in the production of notes of value according to the present invention,
• Figure 2 is a schematic view of a value sheet printed with a new, undeformed printing plate, which has 6 x 4 = 24 security impressions or single use and on which the later cut lines are shown in dashed lines are; 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 shows the sheet of figure 2 with the distorted total print image and the dot-dash lines, later cut lines whose locations end approximations due to the _A of the feed lengths are corrected,
• FIG. 4 shows 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,
• 5 shows a sheet having 4 × 4 = 16 security impressions with a distorted printed image, which is processed using intermediate cuts and on which the later cutting lines are indicated by dashed lines, and
• 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 the case of a bundle cut.

Figure 1 shows schematically those processing stations at which process steps take place according to the invention. 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 print 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 engraving printing unit 20 in the form of an input stack S1, pass through the engraving 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 prints or so-called individual benefits, which are arranged in a matrix in six rows, each with four security prints. FIG. 2 shows an enlarged sheet 10 of this type with its six rows of banknotes 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 when it passes through the printing units in the transport direction F ₀ is the so-called gripper edge 14 (FIGS. 1 and 2), and the value rows 1 to 6 are oriented parallel to this gripper edge 14, that is to say transversely to the direction of the sheet passing through the printing units . 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 are then input from an input stack S3 into a numbering machine 21 for numbering the individual uses and placed at the output thereof on an output stack S4.

The numbered sheets are then successively fed to an automatic cutting machine in stacks. For this purpose, according to FIG. 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 slider is known in the known manner 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 sheet edge is cut here that forms the rear edge of the strip layers during the later bundle cut, that is, in the example under consideration, the left side edge 15 in the feed direction. The sheet 10 is then carried out in the strip cutting device 27, which is designed as a cross cutting device, first at the front of the stack the edge trim of the front edge 16 of the sheet 10 (Figure 2), then the stack is divided step by step into each of its six stripe layers 18, which correspond to the six value rows 1 to 6, and finally on the back of the last stripe layer the rear Edge trimming of the gripper edge 14 is carried out. 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 to 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 in previously known installations there was a single template common to all strip layers is provided with a slide, 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 sliders 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 one another at a small distance, are then moved together by means of the feed device 32 in the direction of the arrow F2 to the bundle cutter 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 cut step by step into three bundles of notes 19, which are already banded and in which the notes of value are in their finished format to have. With 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 bill of value sheets into banded bundles of note and 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 US 4,283,902 by the same applicant, as well as in older Swiss patent application 6 740 / 81 by the same applicant.

The banded bundles 19 cut into 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 certain one Series are formed and then these bundle packages are banded and packed. This further processing is the subject of, for example, the Swiss patent specification CH 577 426 and the American patent specifications US 3 939 621 and 4 045 944 by the same applicant.

_A usser the use of individual feed devices, there is a further difference to the prior art in the here described with reference to the Figure 1 cutting machine to feed the individual layers of strips is that only one longitudinal cutting unit 25, the sheet is provided from later explained reasons to trim one side edge and is carried out of the edge trim on the opposite sides ündelschneidwerk only in _B, while it is known and customary, instead of a longitudinal cutting mechanism before the _S treifenschneidwerk 27 provide two opposite longitudinal cutting stations, which cut each stack simultaneously on two opposite side edges on format.

• - der Abstand D=D 0 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=E_o 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 are now all feed lengths and feed steps, which determine when cutting strips and in bundle section, the exact cutting lines predefined for the respectively machined arc type once and for all and before the start of the processing operations, depending on the given arc and _W ertscheinformat and the benefit number firmly to the automatic feed devices are set, which are electronically programmable for this purpose. These fixed values include:

• the distance D = D 0 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 = E _o between the starting 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 between successive bundle cuts, each of which has the length b of a note 12.

According to the definitions D = _D -d and E = E _o -e given in FIG. 1, the mentioned 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 E.

0

Also 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, a, E _o and b are used. As long as there is no noticeable expansion 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 the security prints also shown rectangular in FIG. 2 13 are all undistorted and of the same size and, after the sheet 10 has been cut along the dashed lines in value notes 12 with the same axb format, are 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 pressure which is exerted by the printing cylinder during each printing process. This deformation is particularly strong in the case of an engraving pressure plate, since a particularly high pressure has to 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 takes on 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 overall printed image of all the security impressions of a sheet 10 and is shown in dash-dotted lines in FIG. 2, and each individual security impression are distorted approximately in a trapezoidal manner.

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. In addition, those lines are drawn in dashed lines in FIG. 3 which would have to form the cutting lines in the later strip and bundle cut, so that despite the distortion in all the manufactured notes, the security impressions (not shown in FIG. 3) are at least approximately in the mirror, i.e. are centered in relation to the blank 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 “nominal cutting lines”, which thus define the corrected dimensions of the notes of value.

In the example according to FIG. 3, a state of expansion 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 Fl. 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 or a + 6x enlarged. The total elongation in the direction Fl is therefore 21x, which is equal to the amount d shown in FIG. 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, i.e. parallel to the gripper edge 14 (i.e. the security impressions including their unprinted border) initially decrease along each of the value rows 1 to 6, starting with a value which is enlarged compared to the original dimension b, and then increasing again and are also gradually increased from value series to value series, viewed in the direction of Fl. 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 respectively, the outer individual uses have the dimensions b + 4y, b + 5y and b + 6y and the middle ones the dimensions b + 2y, b + 2,5y and b + 3y.

With a sheet size of, for example, 500 x 750 mm, 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, 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 other banknotes indicate this a more or less shifted print image from its central position, whereby these centering errors are greatest for the value 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 the strip cut in the direction Fl and in the case of the bundle cut in the direction F2.

The correction for the strip cut should first be considered. In order to realize a fully automatic control of the feed varying during the strip cut, 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 marks are immediately before the sheet enters stack in the strip cutter 27 read by a reader 28 (Figure 1), which brings the sheet stacks to a standstill in the intended cutting position.

The distance of the reading device 28 from the knife of the strip cutting unit 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 reading device 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 and exactly reproducible size 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 -d, d increasing with increasing pressure plate expansion, so that the width of the front edge 16 of the sheets cut off during the first cut in the course of the company becomes correspondingly smaller. The following markings m precisely control the sequence of the successively 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 processes in the cutting machine are carried out, it is only necessary to ensure that the side edge 17 of the sheet which has the markings m is only cut off after the strip cuts, which in the example under consideration in FIG _B ündelschneidwerk 37 carried by the front edge trimming.

Instead of individual markings, it is also possible to provide double markings which, as indicated in FIG. 3, consist of two line-shaped markings or mouth m located at a small 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 run-in accuracy into the cutting position and is expedient if the sheet stacks are pushed in the usual manner, 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 are the four individual blanks belonging to a bank note series of different lengths within a strip layer, but also within a group of the six strip layers belonging to the same stack become longer in the direction F1 from strip position to strip position, as has already been explained with reference to FIG. 3. 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. To achieve this, the feed device 32, as indicated schematically in FIG. 4, consists of a number of separate, independently controllable feed legs corresponding to the number of strip layers per stack directions 321 to 326, each of which with its associated slide 311 to 316 individually moves one of the strip layers 18, which correspond to the value rows 1 to 6. 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 cut in the longitudinal cutter 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 line delimiting the side edge 15 the trapezoidal outline 11 'of the overall printed image; this cutting line includes the angle α with the gripper edge 14 (FIG. 3), which becomes greater than 90 ° with the beginning of the 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 α relative to the gripper edge 14, starting from an originally right angle, can be made ever larger during operation. Corresponding to this cutting angle u6, 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 α of the slitter 25 can be controlled automatically will be explained later; at this point 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 in each case, corresponding to 500 to 1 ' 000 stacks of 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 would not have to be printed on edge strips cut off later, 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 specific 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, can be found practically on all printed values and can be used as a natural marking selectively recognizable by a reading device, which defines the adjacent cutting line. Readers with the required selectivity stand at the high level of development Photoelectric devices are readily available or are easily customizable. 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 to control 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 contrast for the feed control in the bundle cut is the contrast between the light-colored 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 to moving these strip layers Control 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 due to 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 responds first 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 security print 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 are correspondingly controlled by the readers 342 to 346 and which correspond to the value series 2 to 6, increase successively and are designated in FIG. 4 by E2, E3, E4, E5 and E6. In general, E _i = E - 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, e ₁ = ¹ 8 ^y, e2 ⁼ 15 ^y, e3 ⁼ 12 ^y , e ₄ ⁼ 9 ^y , e ₅ = 6y and ^e ₆ ⁼ 3y.

The simultaneous front edge trimming takes place in the bundle cutter 33 only when all six strip positions 18 have assumed their desired cutting position. The subsequent successive feed steps are then individually controlled by the reading devices for each strip position in such a way that they have the lengths indicated in FIG. 3 and already discussed the lengths b + 6y, b + 3y, 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 cutting lines are shown in dash-dot lines on the strip layers 18 in FIG.

In this way, all the notes of value leaving the bundle cutter 33 have an at least approximately mirror image and edges running at right angles to one another, with the exception of the last notes of the strip layers 18 in each case, whose edges in the direction F2, for the reasons explained earlier, in the case of greater elongations of the pressure 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 longitudinal cutting device 25, it is necessary to measure a quantity that is characteristic of the elongation state of the overall printing image 11 ′, that is to say, for example, the length of the boundary of this overall printing image 11 ′ adjacent to the sheet edge 16. As can readily be seen, the angle ₀ 6 entered in FIG. 3 increases with increasing length of this print image limitation according to a relationship that can be determined theoretically and / or empirically for a given type of printing plate. To measure this dimension of the total print image, which is approximately 4b + 18y in the example considered according to FIG. 3, a measuring device 351, schematically indicated in FIG. 4, can be provided on the feed device 321, which measures the sum of the four feed steps covered in the bundle cuts of a strip position; this sum, 4b + 18y in the example under consideration, corresponds exactly to that required th length dimension from which the cutting angle oJ 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 α and issues a control command for corresponding control of the cutting position of the longitudinal cutting device 25. Of course, other methods for measuring the respective distortion state of the overall print 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 F1 (FIG. 3) is known, then the corresponding strain in the direction F2 can be calculated on the basis of this relationship or at least estimated with an accuracy that is sufficient for the present purposes. A measuring device 36, 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 sheet stack, as has already been explained for the measuring device 351 of the feed device 321. It is sufficient, for example, to measure only the feed length D = D -d and thus the increasing change in length d of the sheet 10 and program it accordingly enter ten mini-computer or microprocessor, 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 reading device 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 c6-, 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 traveled feed paths 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 path 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 to which a program has been entered which detects the increasing elongation of the printing plate in question as a function of number of Describes prints. The course of the expansion of a certain type of printing plate with the number of prints carried out can be determined mathematically and / or empirically or on the basis of empirical values, and a complete program for feed control can be drawn up from this.

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 and b and are always re-programmed by hand in the course of operation as soon as the Centering errors appearing become visible to the naked eye or begin to become disruptive. For example, after 100,000 prints, that is to say after the passage of 1,000 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, where, for example, x = y = 0.05 mm is selected; this then results in the other correction variables d of approximately 1 mm and the various e _i corrections. Such changes in the feed programming by modifying the correction variables x or 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 variables to be introduced in each case can either be determined in advance from the theoretically or empirically known course of the pressure plate expansion or from case to case can be determined by an inspection and measurement of the stretched printing plate or the distorted outline of the overall printed 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 Fo), because namely the widening in the transverse direction is symmetrical on both sides and therefore the security impressions in the central region of the sheets are only relatively slightly after the one and be shifted towards the other side and the security prints lying on the outside experience a shift which 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 bank note 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 from its moisture content and 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 prints is subject for other reasons.

The examples described above concerned the cutting of the sheets and strip layers by individual cuts, which has the consequence that, due to the different feed steps, the format of the value notes generated 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, according to 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 Figures 5 and 6. FIG. 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 the security prints 113 is again distorted in a trapezoidal manner.

Those later cut lines which, despite this distortion, ensure an approximate centering of the security impressions 113 within their border are drawn in with dashed lines and selected such 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 those between the individual uses vary _Z wipe strips which are cut off as waste strips later. The width of the intermediate strips Z1, Z2 and Z3 lying between adjacent value note rows 101 to 104 decreases exactly to the extent in the direction of 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 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 bank note series, which are designated in FIG. 5 for bank note series 101 with Z11, Z12 and Z13 and for bank note series 104 with Z41, Z42 and Z43, change individually and in each bank note series differently in an analogous manner to that using the example of Figures 3 and 4 described feed steps of the individual strip layers in the bundle cuts. When cutting a stack with the sheets 110, both the strip cutting unit 27 and the bundle cutting unit 33 are controlled in such a way that those feeds which define the cutting lines in the case of a waste cut (i.e. when cutting off the front edge or an intermediate strip) are dependent 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 the automatic control of the feed, in the example according to FIG. 5, on the one hand, print markings m are again provided on the side edge 117, which are read by the reading device 28 for the purpose of feed control during the strip cut, and on the other hand print marks Markings n, which are printed on the intermediate strip between adjacent individual uses of each bank note series and are read by 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 the 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 immediately.

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 programmed feed step 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 notes of value, the notes of which are always at least approximately centered and which all have the same format, if one disregards the small inaccuracy that results for the last bundle of notes of the strip layers as a result of the side edge trimming in the longitudinal cutter 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 printing 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. A process for the production of freshly printed notes of value cut to format, after which sheets of notes are printed with security prints arranged in the form of a matrix and placed on top of one another in stacks, and the sheet stacks thus formed are automatically cut into strip layers with stepwise advance and these strip layers are then cut into bundles of notes, characterized in that at Strip cut and / or in the case of a bundle cut, the lengths of the feed movements between successive strip cuts or bundle cuts are changed individually in dependence on the increasing elongation of the printing plate of the sheet-fed printing machine in such a way that the printed image of the cut-to-size notes is at least approximately its exact centering in relation to the edge of the note maintains. 2. The method according to claim 1, characterized in that at least with the bundle cuts worked with intermediate cuts and only the length of the feed steps, which determine the size of the waste strips, is changed depending on the increasing pressure plate expansion, while the length of the feed steps, which is at least Bundle cut determine the format of the notes of value, always remains constant. 3. The method according to claim 1 or 2, characterized in that the strip cuts are made parallel to the gripper edge of the sheet, wherein the gripper edge is in the feed direction behind that the length of the feed of a sheet stack from a given starting position, in which its gripper edges out are directed up to the position in which the edge trimming of the front edges takes place in the strip cutting device, with increasing expansion of the printing plate, is reduced compared to the initial value corresponding to the undeformed printing plate, and that the respective first feed steps, which when cutting the sheet stack the width of the first layer of strips or the first waste strip that occurs with intermediate cuts, increases with increasing expansion of the printing plate compared to the initial value corresponding to the undeformed printing plate, and the other feed steps, which determine the widths of the following strip layers or waste strips when cutting a stack of sheets, successively compared to the respective first feed step be made smaller. 4. The method according to any one of claims 1 to 3, characterized in that the bundle cuts are made perpendicular to the gripper edge and that the respective first feed steps, which determine the dimensions of the first bundle of notes of value or the first waste strips occurring in the case of intermediate cuts in the feed direction when cutting the strip layers, with increasing elongation of the printing plate compared to the initial value corresponding to the undeformed printing plate, the remaining feed steps, which determine the dimensions of the following bundles of notes or waste strips when cutting a strip layer, are initially reduced in comparison to the first feed step up to cuts in the central region of a strip layer and then be enlarged again, the corresponding feed steps being selected for each of the strip layers belonging to one and the same sheet stack, the greater the further the strip layer concerned from the strip position adjacent to the gripper edge is removed. 5. The method according to claim 4, characterized in that before the bundle cuts a perpendicular to the gripper edge oriented side edge of the sheet or the strip layers along a cutting line which is at least approximately parallel to the adjacent lateral boundary of the overall print image on the sheet and therefore with increasing elongation of the printing plate encloses an opposite 90 ⁰ increasing angle with the gripper edge, and that the length of advance of the layers of strips from a given initial position, which is defined by the position and orientation of said truncated side edges, to that position in which the edge trimming of the front edge of the Strip position in the bundle cutting unit takes place with increasing expansion of the printing plate compared to the initial value corresponding to the undeformed printing plate, the mentioned feed length being increased by for all of the strip layers belonging to one and the same sheet stack is chosen to be smaller the further the strip position in question is from the strip layer adjacent to the gripper edge. 6. The method according to claim 5, in which all of the strip layers belonging to one and the same sheet stack are collected next to one another in their starting position, are jointly advanced to the bundle cutting unit, and are simultaneously cut there step by step into bundles of notes, characterized in that the feed length to the bundle cutting unit and the individual feed steps during bundle cutting can be set separately and controlled and controlled for each individual strip position. 7. The method according to any one of claims 1 to 6, characterized in that the lengths of the feed movements are reset by hand after each passage of a certain number of sheet stacks. 8. The method according to any one of claims 1 to 6, characterized in that the lengths of the feed movements can be controlled by means of a computer on the basis of a program adapted to the increasing elongation of the printing plate. 9. The method according to any one of claims 1 to 6, characterized in that at least one side edge of the sheet oriented parallel to the feed direction of the sheet stack during the strip cut, which is cut off at a later edge trimming, during the printing of the sheet with edge markings made on the printing plate (m ) is printed, which define the position of the later strip cuts or waste cuts, and that the length of the feed movements leading into these cutting positions is automatically controlled as a function of these edge markings (m) read by a reading device. 10. The method according to any one of claims 7 to 9, characterized in that the lengths of the variable feed movements carried out during the strip cut are automatically measured and stored in a computer and that during the subsequent bundle cut of the strip positions concerned, the feed lengths to be changed are automatically based on these stored values a program input to the computer, which relates the elongation of the printing plate in the longitudinal direction to the elongation in the transverse direction. 11. The method according to claim 2 or 9, characterized in that at least in the bundle cut with intermediate cuts, and during the printing of the sheets those areas which are eliminated as waste strips in these later intermediate cuts are also attached to the printing plate Markings (n) are printed, which define the position of the later intermediate cuts, and that the lengths of the feed movements, which determine the width of the waste strips, are automatically controlled as a function of these markings (n) read by readers. 12. The method according to claim 9 or 11, characterized in that two individual markings per cutting line are applied as edge markings (m) or markings (n) on the later waste strips and that the reading of the first individual marking in the feed direction reduces the normal feed speed a creeping movement and the reading of the second individual marking causes the feed movement to stop. 13. The method according to any one of claims 1 to 6, characterized in that the lengths of the feed movements to be changed can be controlled by detectors, which on the same selected characteristic points in each security impression, such as patterns, color markings or contrasts, in particular on the contrast between the bright value edge and a dark area of the security impression. 14. Automatic cutting machine for carrying out the method according to claim 1, with strip and bundle cutting units and with these cutting units, automatically working and adjustable feed devices for the sheet stacks and the strip layers, in particular with linear amplifiers which have a hydraulic cylinder with a pressure medium supply which can be metered by a stepper motor, characterized in that the feed movements of the feed devices (26, 32) when cutting a stack of sheets and, if necessary, when cutting a layer of strips can be changed individually from step to step and can be controlled as a function of a specified program or by reading devices (28, 34) which respond to print marks (m, n) on the sheet or to characteristic locations on the security prints (13). 15. Cutting machine according to claim 14 with a bundle cutter, which all strip layers belonging to one and the same sheet stack are fed together by movement in the longitudinal direction and in which these strip layers are simultaneously cut into bundles of notes, characterized in that all the strip layers mentioned (18; 118) each have one individual feed device (321 to 326) is assigned, which can be controlled separately from the others. 16. Cutting machine according to claim 14 or 15, characterized in that a cutting device (25) is provided for trimming the edge of that sheet edge (17) which forms the rear edge during the feed movements of the strip layers (18) in the bundle cut, 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 feed devices (321 to 326) mentioned, which act on this trimmed edge of the strip layers (18) and advance them during the bundle cut, as a function of the increasing elongation of the printing plate are changeable.

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