EP1790473A1 - Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression - Google Patents

Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression Download PDF

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Publication number
EP1790473A1
EP1790473A1 EP05111342A EP05111342A EP1790473A1 EP 1790473 A1 EP1790473 A1 EP 1790473A1 EP 05111342 A EP05111342 A EP 05111342A EP 05111342 A EP05111342 A EP 05111342A EP 1790473 A1 EP1790473 A1 EP 1790473A1
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EP
European Patent Office
Prior art keywords
printing press
printing
wiping
cylinder
behaviour
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05111342A
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German (de)
English (en)
Inventor
Volker Lohweg
Johannes Georg Schaede
Thomas TÜRKE
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KBA Notasys SA
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KBA Giori SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by KBA Giori SA filed Critical KBA Giori SA
Priority to EP05111342A priority Critical patent/EP1790473A1/fr
Priority to CN201110225457.9A priority patent/CN102381019B/zh
Priority to JP2008541880A priority patent/JP5400386B2/ja
Priority to PCT/IB2006/054367 priority patent/WO2007060615A1/fr
Priority to US12/093,179 priority patent/US8613254B2/en
Priority to ES06831898.9T priority patent/ES2487498T3/es
Priority to EP06831898.9A priority patent/EP1965982B1/fr
Priority to RU2008124204/12A priority patent/RU2436679C2/ru
Priority to CNA2006800442250A priority patent/CN101316709A/zh
Publication of EP1790473A1 publication Critical patent/EP1790473A1/fr
Priority to JP2012219544A priority patent/JP5395242B2/ja
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F33/00—Indicating, counting, warning, control or safety devices
    • B41F33/0036—Devices for scanning or checking the printed matter for quality control

Definitions

  • the present invention generally relates to inspection of the quality of printed substrates which are processed on printing presses. More specifically, the present invention relates to in-line inspection of printed substrates, such as printed sheets or webs, i.e. methods for detection of occurrence of printing errors on printed substrates during processing thereof on a printing press. The present invention is in particular directed to detection of occurrence of printing errors on printed substrates for the production of security documents, especially banknotes.
  • Quality inspection of printed products is conventionally limited to the optical inspection of the printed product. Such optical inspection can be performed as an off-line process, i.e. after the printed products have been processed in the printing press, or, more frequently, as an in-line process, i.e. on the printing press where the printing operation is carried out.
  • Optical inspection systems which are basically adapted to inspect printed products at large are already available on the market. These inspection systems typically work in the RGB domain based on the to be now designated as classic threshold-based inspection methods. Such inspection methods are for instance disclosed in US Patents N° 5,384,859 and N° 5,317,390 . These publications disclose so-called iconic pixel-difference or threshold inspection methods, i.e. inspection methods which are based on the analysis of pixel density differences between sample images of the printed products and reference images.
  • the threshold parameters are usually defined based on a comparison of several master images, whereby mean values or standard deviations are determined in local regions of the images and are attributed corresponding thresholds or tolerances. These values and tolerances are then compared with actual image values measured on sample images of the inspected material.
  • Threshold-based inspection methods exhibit a certain number of disadvantages as described in detail hereinafter. These inspection methods may be adapted for inspection of security documents, but under certain conditions. Threshold-based inspection methods are not directly suited for the inspection of security documents, as security documents are printed using specific printing processes (such as intaglio printing for instance) which are not commonly used in commercial printing. The conventional threshold-based inspection methods must accordingly be adapted to the specific printed features of security documents.
  • optical inspection methods are by definition limited to inspection of the optical quality of the printed products, such as whether too much or too little ink has been applied onto the printed material, whether the density of the applied ink is acceptable, whether the spatial distribution of the applied ink is correct, etc. While these systems are adapted to detect such printing errors in a relatively efficient manner, the known inspection systems are however unable to perform an early detection of progressively-building printing errors. Such printing errors do not occur in an abrupt manner, but rather in a progressive and cumulative manner. These printing errors typically occur because of a gradual degradation or deviation of the behaviour of the printing press. As optical inspection systems inherently exhibit inspection tolerances, printing errors will only be detected after a certain period of time, when the tolerances of the optical inspection system are exceeded.
  • a general aim of the present invention is thus to improve the known inspection techniques and propose an inspection methodology that can ensure a comprehensive control of the quality of the printed substrates processed by printing presses, especially printing presses that are designed to process substrates used in the course of the production of banknotes, security documents and the like.
  • an aim of the present invention is to propose a method that is suited to be implemented as an expert system designed to facilitate operation of the printing press.
  • it is particularly desired to propose a methodology that can be implemented in an expert system adapted to predict the occurrence of printing errors and/or provide an explanation of the likely cause of printing errors, should these occur.
  • a method for detection of occurrence of printing errors on printed substrates during processing thereof on a printing press comprising the steps of providing multiple sensors on functional components of the printing press to monitor the behaviour of the printing press during processing of the printed substrates and performing an in-line analysis of the behaviour of the printing press to determine occurrence of a characteristic behaviour of the printing press which leads or is likely to lead to occurrence of printing errors on the printed substrates or which leads or is likely to lead to good printing quality of the printed substrates.
  • the above method comprise coupling the in-line analysis of the behaviour of the printing press with an in-line optical inspection of the printed substrates.
  • In-line optical inspection includes (i) optically acquiring images of the printed substrates processed on the printed press, and (ii) processing the acquired images of the printed substrates in order to identify possible occurrence of printing errors on the printed substrates.
  • in-line analysis of the behaviour of the printing press is coupled to in-line optical inspection of the printed substrates in such a way as to issue an early warning of the likely occurrence of printing errors upon determination of a faulty or abnormal behaviour of the printing press while the acquired images are still determined to be devoid of printing errors.
  • the printing press behaviour is monitored while the printed substrates are optically inspected to check the printing quality thereof and, if a faulty or abnormal printing press behaviour is detected, an early indication of a possible future occurrence of printing errors is provided.
  • the early warning of the possible occurrence of printing errors enables a printing press operator to make appropriate changes to the printing press so as to prevent occurrence of the printing errors or limit as much as possible the amount of time between the actual occurrence of the printing errors and the corrective changes to the printing press.
  • in-line analysis of the behaviour of the printing press is coupled to in-line optical inspection of the printed substrates in such a way as to provide an indication of the likely cause of the occurrence of the printing errors.
  • one or more explanations of the possible cause of the printing errors may be given based on the analysis of the printing press behaviour during processing of the printed substrates.
  • Analysis of the behaviour of the printing press is preferably performed by modelling characteristic behaviours of the printing press using appropriately located sensors to sense operational parameters of the functional components of the printing press that are exploited as representative parameters of the said characteristic behaviours.
  • characteristic behaviours comprise:
  • characteristic behaviours of the printing press can be modelled with a view to reduce false errors or pseudo-errors, i.e. errors that are falsely detected by the optical inspection system as mentioned hereinabove, and optimise the so-called alpha and beta errors.
  • Alpha error is understood to be the probability to find bad sheets in a pile of good sheets
  • beta error is understood to be the probability to find good sheets in a pile of bad sheets.
  • the use of a multi-sensor arrangement i.e. a sensing system with multiple measurement channels efficiently allows to reduce the said alpha and beta errors
  • determination of whether the sensed operational parameters of the functional components of the printing press are indicative of a faulty or abnormal behaviour of the printing press is carried out by monitoring the operational parameters of the functional components of the printing press during processing of the printed substrates on the printing press and by determining whether the monitored operational parameters are indicative of any one of the modelled characteristic behaviours of the printing press.
  • Modelling of faulty or abnormal behaviours of the printing press preferably includes:
  • determination of whether the sensed operational parameters of the functional components of the printing press are indicative of a faulty or abnormal behaviour of the printing press is carried out by determining whether the monitored operational parameters show a correspondence with any one of the defined models of the faulty or abnormal behaviours of the printing press.
  • Fuzzy pattern classification techniques are preferably used in order to implement the machine behaviour analysis.
  • sets of fuzzy-logic rules are used to characterize the behaviours of the printing press and model the various classes of printing errors that are likely to appear on the printing press. Once these fuzzy-logic rules have been defined, these can be applied to monitor the behaviour of the printing press and identify a possible correspondence with any printing press behaviour which is leading or likely to lead to the occurrence of printing errors.
  • Figure 1 shows a sheet-fed printing press in the form of an intaglio printing press 1 comprising, as is usual in the art, a sheet feeder 2 for feeding sheets to be printed, a printing unit 3 for printing the sheets, here by intaglio printing, and a sheet delivery unit 4 for collecting the freshly-printed sheets.
  • the printing unit 3 is adapted for intaglio printing and typically includes an impression cylinder 7, a plate cylinder 8 carrying intaglio printing plates (in this example, the plate cylinder 8 is a three-segment cylinder carrying three intaglio printing plates 8a, 8b, 8c - Figure 2), an inking system 9 for inking the surface of the intaglio printing plates 8a, 8b, 8c carried by the plate cylinder 8 and a wiping unit 10 for wiping the inked surface of the intaglio printing plates 8a, 8b, 8c carried by the plate cylinder 8 prior to printing of the sheets.
  • Similar examples of intaglio printing presses are disclosed for instance in EP 0 091 709 , EP 0 406 157 or EP 0 873 866 .
  • the sheets are fed from the feeder unit 2 onto a feeding table and then onto the impression cylinder 7.
  • the sheets are then carried by the impression cylinder 7 to the printing nip formed by the contact location between the impression cylinder 7 and the plate cylinder 8 where the intaglio printing is performed.
  • the sheets are transferred from the impression cylinder 7 to a sheet transporting system 11 in order to be delivered to the delivery unit 4.
  • the sheet transporting system 11 conventionally comprises an endless conveying system with a pair of endless chains driving a plurality of spaced-apart gripper bars for holding a leading edge of the sheets (the freshly-printed side of the sheets being oriented downwards on their way to the delivery unit 4), sheets being successively transferred from the impression cylinder 7 to a corresponding one of the gripper bars.
  • the freshly-printed sheets are preferably inspected by an optical inspection system 5.
  • the optical inspection system 5 is advantageously disposed on the path of the sheet transporting system 11, right after the printing unit 3.
  • Such an optical inspection system 5 is already known in the art and does not need to be described in detail. Examples of optical inspection systems adapted for use as optical inspection system 5 in the intaglio printing press of Figure 1 are for instance described in International applications WO 97/37329 and WO 03/070465 .
  • optical inspection systems suitable for performing optical inspection of the printed sheets might also be found in EP 0 527 453 , EP 0 543 281 , WO 97/48556 , WO 99/41082 , WO 02/102595 , EP 0 820 864 , EP 0 820 865 , EP 1 142 712 , EP 1 167 034 , EP 1 190 855 , EP 1 231 057 and EP 1 323 529 .
  • the optical inspection system 5 is adapted to carry out optical inspection of the printed sheets and detect occurrence of printing errors.
  • optical inspection can for instance be carried out according to the principles disclosed in US Patents N° US 5,317,390 and 5,384,859 (see also EP 0 527 285 and EP 0 540 833 ) or any other suitable optical inspection principle.
  • the printed sheets are preferably transported in front of a drying unit 6 disposed after the inspection system 5 along the transport path of the sheet transporting system 11. Drying could possibly be performed prior to the optical inspection of the sheets.
  • good sheets i.e. sheets that are considered to be acceptable from the point of view of printing quality following inspection
  • good sheets are delivered to one of two sheet delivery piles (one pile being fed while the other one can be emptied from previously delivered sheets).
  • Bad sheets i.e. sheets that are not considered to be acceptable form the point of view of printing quality following inspection, are delivered to a third sheet delivery pile.
  • FIG 2 is a schematic view of the printing unit 3 of the intaglio printing press 1 of Figure 1.
  • the printing unit 3 basically includes the impression cylinder 7, the plate cylinder 8 with its intaglio printing plates 8a, 8b, 8c, the inking system 9 and the wiping unit 10.
  • the inking system 9 comprises in this example four inking devices, three of which cooperate with a common ink-collecting cylinder or Orlof cylinder 9.5 (here a two-segment cylinder) that contacts the plate cylinder 8.
  • the fourth inking device is disposed so as to directly contact the surface of the plate cylinder 8.
  • the illustrated inking system 9 is accordingly adapted for both indirect and direct inking of the plate cylinder 8.
  • the inking devices cooperating with the ink-collecting cylinder 9.5 each include an ink duct 9.10, 9.20, 9.30 cooperating in this example with a pair of inking rollers 9.11, 9.21 and 9.31, respectively.
  • Each pair of inking rollers 9.11, 9.21, 9.31 in turn inks a corresponding chablon cylinder (also designated as selective inking cylinder) 9.13, 9,23, 9.33, respectively, which is in contact with the ink-collecting cylinder 9.5.
  • the fourth inking device includes an ink duct 9.40, an additional inking roller 9.44, a pair of inking rollers 9.41 and a chablon cylinder 9.43, this latter cylinder being in contact with the plate cylinder 8.
  • the additional ink roller 9.44 is necessary in this latter case as the fourth inking device 9.4 is used to directly ink the surface of the plate cylinder 8 which rotates in opposite direction as compared to the ink collecting cylinder 9.5.
  • the surface of the chablon cylinders 9.13, 9.23, 9.33 and 9.43 is structured so as to exhibit raised portions corresponding to the areas of the intaglio printing plates 8a, 8b, 8c intended to receive the inks in the corresponding colours supplied by the respective inking devices.
  • the wiping unit 10 preferably comprises a wiping tank 10.1 (which is movable towards and away from the plate cylinder 8), a wiping cylinder 10.2 disposed in the wiping tank and contacting the plate cylinder 8, at least a first blade (or dry blade) 10.3 contacting the surface of the wiping cylinder 10.2 for removing wiped ink residues from the surface of the wiping cylinder 10.2, cleaning means 10.4 for applying a wiping solution onto the surface of the wiping cylinder 10.2, and a drying blade 10.5 contacting the surface of the wiping cylinder 10.2 for removing wiping solution residues from the surface of the wiping cylinder 10.2.
  • the cleaning means 10.4 typically include a group of spray devices and cleaning brushes for spraying the wiping solution onto the surface of the wiping cylinder 10.2 and cleaning the surface of the wiping cylinder 10.2.
  • the first blade or dry blade 10.3 typically removes approximately 80% of the ink residues from the surface of the wiping cylinder 10.2, while the cleaning means 10.4 remove the remaining part of the ink residues under action of the sprayed wiping solution and cleaning brushes.
  • the drying blade 10.5 has the purpose of drying the surface of the wiping cylinder 10.2 and removing wiping solution residues from the surface thereof so as to prevent such wiping solution residues from contaminating the surface of the plate cylinder.
  • Wiping units of the type comprising spray devices and cleaning brushes as mentioned hereinabove are further described, for instance, in US Patent 4,236,450 , EP 0 622 191 and WO 03/093011 .
  • Other types of wiping units might be envisaged, such as immersion-type wiping units as described in CH 415 694 , US 3,468,248 and US 3,656,431 wherein the wiping cylinder is partly immersed in the wiping solution.
  • the printing quality of the printed sheets is typically controlled solely by means of a suitable optical inspection system which is adapted to optically acquire images of the printed sheets and determine, based on a processing of these acquired images, occurrence of printing errors on the printed sheets.
  • optical inspection of the printed end-product inherently has various problems, in particular is not capable of providing an early warning of the occurrence of printing errors nor an explanation of the likely cause of these printing errors.
  • the printing press to be monitored is provided with multiple sensors that are disposed on functional components of the printing press.
  • these sensors are intended to monitor the behaviour of the printing press during processing of the printed substrates, the sensors must be appropriately selected and be disposed on adequate functional components of the printing press.
  • the actual selection of sensors and location thereof on the printing press will depend on the configuration of the printing press one wishes to monitor the behaviour of. These will not be the same, for instance, for an intaglio printing press and for an offset printing press as the behaviours of these machines are not identical.
  • the sensors must be chosen and located in such a way as to sense operational parameters of selected functional components of the printing press that permit a sufficiently precise and representative description of the various behaviours of the printing press.
  • the sensors should be selected and positioned in such a way as to sense and monitor operational parameters that are as much uncorrelated to each other as possible. Indeed, the less correlated the operational parameters are, the more precise the definition of the behaviour of the printing press will be. For instance, monitoring the respective rotational speeds of two cylinders that are driven by a common drive will not as such be very useful as the two parameters are directly linked to one another. In contrast, monitoring the current drawn by an electric motor used as a drive means of the printing press and the contact pressure between two cylinders of the printing press will provide a better description of the behaviour of the printing press.
  • sensors should be made in view of the actual set of behaviour patterns one desires to monitor and of the classes of printing errors one wishes to detect.
  • sensors might be provided on the printing press in order to sense any combination of the following operational parameters:
  • monitoring of key components of the wiping unit has shown to be particularly useful in order to derive a representative model of the behaviour of the printing press as many printing problems in intaglio printing presses are due to a faulty or abnormal behaviour of the wiping unit.
  • the inventors have found that, based on suitable combinations of the above operational parameters, it is possible to model the behaviour of the printing press and identify whether or not the monitored behaviour of the printing press evolves towards an abnormal of faulty behaviour that leads or is likely to lead to the occurrence of printing errors. Accordingly, by performing an in-line analysis of the behaviour of the printing press during printing and/or processing of the substrates it is possible to determine occurrence of a faulty or abnormal behaviour that will or is likely to have an impact on the printing quality of the printed substrates.
  • the proposed in-line analysis of the behaviour of the printing press implies performing a trend analysis of the behaviour of the printing press.
  • the analysis is performed over a long duration (i.e. during processing of several successive printed substrates).
  • Such trend analysis is preferable in that it permits identification of a gradual deviation or degradation of the behaviour of the printing press.
  • the in-line analysis of the behaviour of the printing press is based on fuzzy pattern classification techniques.
  • pattern classification or recognition is a known technique that concerns the description or classification of measurements.
  • the idea behind pattern classification is to define the common features or properties among a set of patterns (in this case the various behaviours a printing press can exhibit) and classify them into different predetermined classes according to a determined classification model. More precisely, within the scope of the present invention, the idea is to define a classification model that permits classification of the possible behaviours of a given printing press into different classes of behaviours (or behaviour patterns) corresponding to specific classes of printing errors.
  • Fuzzy pattern classification in particular is an effective way to describe and classify the printing press behaviours into a limited number of classes. Fuzzy pattern classification typically partitions the input space (in the present instance the variables - or operational parameters - sensed by the multiple sensors provided on functional components of the printing press) into categories or pattern classes and assigns a given pattern to one of those categories. If a pattern does not fit directly within a given category, a so-called "goodness of fit" is reported.
  • fuzzy sets as pattern classes, it is possible to describe the degree to which a pattern belongs to one class or to another. By viewing each category as a fuzzy set and identifying a set of fuzzy "if-then” rules as assignment operators, a direct relationship between the fuzzy set and pattern classification is realized.
  • Figure 3 is a schematic view of the architecture of a fuzzy classification system for implementing the printing press behaviour analysis according to the present invention.
  • the operational parameters P1 to Pn sensed by the multiple-sensor arrangement are optionally pre-processed prior to feeding thereof into the pattern classifier.
  • Such pre-processing may in particular include a spectral transformation of some of the signals outputted by the sensors (as explained hereinafter), in particular signals where one expects to find characteristic patterns that are representative of the printing press behaviour.
  • Such spectral transformation will in particular be envisaged for processing the signals representative of vibrations or noises produced by the printing press, such as the characteristic noises/vibrations patterns of intaglio printing presses for instance.
  • the fuzzy pattern classifier is basically implemented as sets of fuzzy "if-then” rules emulating human thinking which are designed to draw links between the printing press behaviour represented by the inputted (and optionally pre-processed) operational parameters P1 to Pn and several determined pattern classes which are each assigned a corresponding class of printing errors.
  • classification is performed into the pre-defined pattern classes and associated classes of printing errors.
  • a corresponding "membership” value or weight also called “score value” or "goodness of fit value”
  • fuzzy models are known as such to those skilled in the art. These include in particular the so-called “Fuzzy Pattern Classification” models (FPC), “Takagi-Sugeno” models and the like. In general, they can be designed with the help of “linguistic” fuzzy rules. Further, output modelling can be designed in different ways, for example using “center of gravity” methods, “Singleton”-based methods, and the like. Within the scope of the present invention, "linguistic" fuzzy modelling techniques and “Singleton”-based output functions appear to be best suited for the purpose of the behaviour classification of the printing press.
  • Figure 4 is an illustrative partial picture of a printed sheet processed on an intaglio printing press as shown in Figure 1. More precisely, Figure A shows a picture of a printed sheet obtained under normal operating conditions.
  • Figure 4A is an illustrative partial picture of a printed sheet processed on the intaglio printing press that exhibits characterizing printing errors due to an inadequate wiping pressure as mentioned under class A hereinabove.
  • the printing errors appear as uniformly inked areas in the regions of the intaglio prints.
  • the inventors have identified that the actual occurrence of the printing errors shown in Figure 4A is not instantaneous, but rather that these printing errors occur after a certain period following decrease of the wiping pressure.
  • By monitoring the current drawn by the electric motor typically driving the printing unit it is possible to detect a decrease in the wiping pressure, such decrease of wiping pressure being reflected as a decrease in the current consumption.
  • the constraints e.g.
  • Figure 4B is an illustrative partial picture of a printed sheet processed on the intaglio printing press that exhibits characterizing printing errors due to contamination with wiping solution as mentioned under class B hereinabove.
  • the printing errors appear as diluted or shady areas in the regions of the intaglio prints.
  • the inventors have identified that the actual occurrence of the printing errors shown in Figure 4B is again not instantaneous, as wiping solution will usually only gradually build up on the intaglio printing plates due to insufficient drying of the wiping cylinder.
  • Figure 4C is an illustrative partial picture of a printed sheet processed on the intaglio printing press that exhibits characterizing printing errors due to a dirty wiping cylinder surface as mentioned under class C hereinabove caused by an insufficient supply of wiping solution.
  • the printing errors appear as randomly-shaped inked areas.
  • the inventors have identified that the actual occurrence of the printing errors shown in Figure 4C is again not instantaneous.
  • By monitoring the current drawn by the electric motor driving the printing unit it is for instance possible to detect a too low amount of wiping solution as the electrical consumption will have a tendency to rise. This measurement can be supplemented with a measurement of the flow of wiping solution. It is thus again possible to define a characteristic model of the faulty behaviour of the printing and predict the occurrence of the printing errors.
  • the other causes of the printing errors mentioned under class C might be monitored in a similar way.
  • printing errors not only occur as a consequence of problems related to the operation of the wiping unit, but that errors might also be the consequence of a dysfunction of other functional components of the printing press, such as for instance an inadequate printing pressure between the plate cylinder 8 and the impression cylinder 7, an inadequate inking of the plate cylinder 8 by the inking system 9, etc.
  • the analysis of the behaviour of the printing press rests on the provision of an adequate multi-sensor arrangement which is adapted to provide measurements of operational parameters of functional components of the printing press that are sufficiently descriptive of the behaviour of the printing press.
  • One particularly advantageous way to measure the behaviour of the printing press is to monitor noises or vibrations produced by the printing press. Such noises or vibrations could theoretically be measured at any appropriate location on the printing press.
  • a particularly adapted location is to measure noises or vibrations on the bearings of a cylinder of the printing press. In the context of the intaglio printing press illustrated in Figures 1 and 2, one suitable location is the supporting shaft of the wiping cylinder 10.2.
  • Figures 5A and 5B are two photographs of a possible sensor arrangement for sensing noises or vibrations produced by the printing press on the axis of the wiping cylinder 10.2.
  • Figure 5A shows a first cylinder bearing 101 of the wiping cylinder 10.2 which is located on the wiping tank 10.1 on the left-hand side (or drive side) of the intaglio printing press, while Figure 5B shows the second opposite cylinder bearing 102 of the wiping cylinder 10.2 (for the sake of clarity Figure 1 shows the intaglio printing press as seen from its drive side).
  • the wiping cylinder 10.2 is not shown in Figures 5A and 5B but would be supported between the two bearings 101 and 102 shown in the photographs.
  • the plate cylinder 8 is partly visible in Figures 5A and 5B.
  • each cylinder bearing 101, 102 there is preferably provided a pair of sensors 51 a, 51 b and 52a, 52b for sensing the noises or vibrations transmitted along two distinct directions perpendicular to the axis of rotation of the wiping cylinder 10.2, in this case horizontally by means of sensors 51 a, 52a as well as vertically by means of sensors 51 b, 52b.
  • the sensors 51 a, 51 b, 52a, 52b may be any suitable sensors sensitive to noises or vibrations, such as acoustic sensors, acceleration sensors or any other pressure-sensitive or vibration-sensitive sensors.
  • Cepstrum is an anagram of “spectrum” and is the accepted terminology for the inverse Fourier transform of the logarithm of the spectrum of a signal. Cepstrum analysis is in particular used for analysing "sounds” instead of analysing frequencies. The cepstrum can be seen as information about the rate of change in the different spectrum bands. It was originally proposed for characterizing the seismic echoes resulting from earthquakes and bomb explosions (see paper entitled “The Quefrency Analysis of Time Series for Echoes: Cepstrum, Pseudautocovariance, Cross-Cepstrum, and Saphe Cracking" of Bogert, Healy and Tukey, 1963).
  • the signals measured at rotating elements of the printing press e.g. noises and/or vibrations produced at the bearings of the wiping cylinder and sensed by acoustic/vibration sensors as mentioned above
  • the signals measured at rotating elements of the printing press are pre-processed using the above-mentioned cepstrum analysis.
  • cepstrum analysis is preferably performed with a view to extract three variables which will be called the "cepstrum per sheet", the “cepstrum 2:3" and the “cepstrum per turn” values, and a trend analysis is performed based on these two variables.
  • the "cepstrum per sheet” value is defined within the scope of the present invention as the value of the cepstrum corresponding to the sheet interval, i.e. the interval of time between two successive sheets.
  • the "cepstrum 2:3" value is defined within the scope of the present invention as the cepstrum value corresponding to the permutation interval of the plate cylinder 8 and Orlof cylinder 9.5 (which are respectively three-segment and two-segment cylinders in this example).
  • the "cepstrum per turn” value is defined within the scope of the present invention as the cepstrum value corresponding to the interval of time (or turn interval) necessary for the plate cylinder of the printing press to make one complete revolution (which interval of time is a multiple of the sheet interval).
  • sheet_interval [ s ] 3600 / sheet_processing_speed [ sheets / h ]
  • permutation_interval [ s ] sheet_interval [ s ] * #_segments_Orlof_cylinder
  • tum_interval [ s ] sheet_interval [ s ] * #_segments_plate_cylinder
  • Figure 6 schematically illustrates an exemplary cepstrum of a noise signal measured at one bearing of the wiping cylinder 10.2, the sheet processing speed of the intaglio printing press being set at 6316 sheets per hour in this example which gives a sheet interval of 0.57 seconds, a permutation interval of 1.14 seconds and a turn interval of 1.71 seconds, the corresponding "cepstrum per sheet”, “cepstrum 2:3" and “cepstrum per turn” values appearing as three peaks in the cepstrum of Figure 6.
  • each of the "cepstrum per sheet” and “cepstrum per turn” values is preferably monitored using a speed-normalized moving band-pass filter for filtering the relevant band in the cepstrum, which band-pass filter is "locked” onto the relevant sheet interval or turn interval, respectively (which intervals are inversely proportional to the sheet processing speed).
  • the maximum value of the resulting filtered signal is detected and the resulting amplitude over time is recorded.
  • Figure 7 schematically illustrates the above-mentioned processing and filtering principle. As shown in the upper-left part of Figure 7, the cepstrum is first filtered around the relevant interval of time (i.e. the sheet interval or the turn interval) using an appropriate speed-normalized band-pass filter (i.e.
  • the in-line analysis of the behaviour of the printing press is coupled with in-line inspection of the printed substrates.
  • the conclusions drawn following pattern classification of the behaviour of the printing press are correlated with those drawn following optical inspection of the printed substrates.
  • the sensed operational parameters might be so characterizing of a faulty or abnormal behaviour of the printing press that it is possible to immediately draw conclusions that the detected faulty or abnormal behaviour will lead to printing errors, without resorting to an optical inspection of the printed substrates.
  • definite conclusions regarding the likely occurrence of printing errors might not be drawn directly and exclusively from the results of the pattern classification of the printing press behaviour. In such instances coupling of the behaviour analysis with an optical inspection of the printed substrates can help.
  • Fuzzy logic techniques are again of use in connection with the coupling of results from inspection of the printed substrates and results from the analysis of the behaviour of the printing press.
  • fuzzy sets can be defined and a higher-rank pattern classifier constructed (in a manner similar to that already explained hereinabove in connection with the pattern classification of the behaviour of the printing press).
  • fuzzy logic techniques have been discussed in connection with the modelling and pattern classification issues, other approaches might be envisaged including modelling techniques making use of so-called neural networks.
  • a fuzzy pattern classifier can be set up by a learning process and a skilled designer (the so-called “expert") based on experimental data and knowledge of the involved processes, whereas neural networks are based on learning processes only. The expert is able to tune the system with the help of "linguistic modifiers".

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  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
EP05111342A 2005-11-25 2005-11-25 Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression Withdrawn EP1790473A1 (fr)

Priority Applications (10)

Application Number Priority Date Filing Date Title
EP05111342A EP1790473A1 (fr) 2005-11-25 2005-11-25 Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression
ES06831898.9T ES2487498T3 (es) 2005-11-25 2006-11-21 Método para detectar la aparición de errores de impresión en sustratos impresos durante el procesamiento de los mismos en una prensa de imprenta
JP2008541880A JP5400386B2 (ja) 2005-11-25 2006-11-21 印刷機上での被印刷体の処理中に被印刷体上の印刷エラーの発生を検出する方法
PCT/IB2006/054367 WO2007060615A1 (fr) 2005-11-25 2006-11-21 Procede de detection des occurrences d'erreur d'impression sur des substrats imprimes au cours du traitement de ces derniers sur une presse a imprimer
US12/093,179 US8613254B2 (en) 2005-11-25 2006-11-21 Method for detection of occurrence of printing errors on printed substrates during processing thereof on a printing press
CN201110225457.9A CN102381019B (zh) 2005-11-25 2006-11-21 在印刷机处理期间用于探测在印刷基质上印刷错误发生的方法
EP06831898.9A EP1965982B1 (fr) 2005-11-25 2006-11-21 Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression
RU2008124204/12A RU2436679C2 (ru) 2005-11-25 2006-11-21 Способ обнаружения дефектов печати на печатной основе в процессе ее обработки в печатной машине
CNA2006800442250A CN101316709A (zh) 2005-11-25 2006-11-21 在印刷机处理期间用于探测在印刷基质上印刷错误发生的方法
JP2012219544A JP5395242B2 (ja) 2005-11-25 2012-10-01 印刷機上での被印刷体の処理中に被印刷体上の印刷エラーの発生を検出する方法

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EP05111342A EP1790473A1 (fr) 2005-11-25 2005-11-25 Méthode pour détecter l'apparition d'erreurs d'impression sur un substrat durant son traitement dans une machine d'impression

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2461883C2 (ru) * 2007-10-02 2012-09-20 КБА-НотаСис СА Способ и система для контролируемого производства защищенных документов, в особенности банкнот

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US3468248A (en) 1963-12-06 1969-09-23 Gualtiero Giori Apparatus for removing ink from the surface of wiping cylinders used in direct steel plate printing
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EP0820864A1 (fr) 1996-07-23 1998-01-28 Komori Corporation Appareil pour guider le papier dans une presse offset à imprimer des feuilles
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EP1142712A1 (fr) 2000-04-07 2001-10-10 Komori Corporation Appareil pour contrôler la qualité d'une machine d'impression à retiration
EP1167034A2 (fr) 2000-06-23 2002-01-02 Komori Corporation Procédé et dispositif d'identification d'objets sous forme de feuilles
DE10132266A1 (de) * 2000-07-11 2002-01-24 Heidelberger Druckmasch Ag Verfahren und Vorrichtung zur Regelung des Übergabepassers in einer Bogenrotationsdruckmaschine
EP1190855A1 (fr) 2000-09-22 2002-03-27 Komori Corporation Appareil pour contrôler la qualité d'impression
EP1231057A1 (fr) 2001-02-09 2002-08-14 Komori Corporation Machine d'impression de feuilles
WO2002102595A1 (fr) 2001-06-15 2002-12-27 Koenig & Bauer Aktiengesellschaft Dispositif de controle de la qualite
EP1323529A1 (fr) 2001-12-27 2003-07-02 Komori Corporation Dispositif pour vérifier la qualité d'impression d'une machine à imprimer
WO2003070465A1 (fr) 2002-02-20 2003-08-28 Kba-Giori S.A. Dispositif de transport de feuilles equipe d'un element guide-feuille
DE10208285A1 (de) 2002-02-26 2003-09-18 Koenig & Bauer Ag Verfahren zur Korrektur der Bilddaten eines Kamerasystems
WO2003093011A1 (fr) 2002-05-06 2003-11-13 Kba-Giori S.A. Buses pour installation de nettoyage d'une machine a imprimer
WO2004017034A1 (fr) 2002-07-26 2004-02-26 Koenig & Bauer Aktiengesellschaft Procede pour analyser des divergences de couleur dans des images a l'aide d'un capteur d'image
DE202004018072U1 (de) * 2004-11-20 2005-01-20 Man Roland Druckmaschinen Ag Bogendruckmaschine

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CH415694A (de) 1963-12-06 1966-06-30 Giori Gualtiero Wischvorrichtung für Stahlstichdruckmaschinen
US3468248A (en) 1963-12-06 1969-09-23 Gualtiero Giori Apparatus for removing ink from the surface of wiping cylinders used in direct steel plate printing
US3656431A (en) 1969-05-23 1972-04-18 De La Rue Giori Sa Devices for cleaning wiping cylinders in a printing apparatus
US4236450A (en) 1976-09-17 1980-12-02 De La Rue Giori S.A. Installation for the continuous cleaning of a wiping roller of a machine for copper-plate printing
EP0091709A1 (fr) 1982-04-07 1983-10-19 De La Rue Giori S.A. Machine taille-douce pour l'impression des papiers valeurs
EP0406157A1 (fr) 1989-06-29 1991-01-02 De La Rue Giori S.A. Machine taille-douce pour l'impression des papiers valeurs
EP0540833A2 (fr) 1991-08-12 1993-05-12 KOENIG & BAUER-ALBERT AKTIENGESELLSCHAFT Contrôle de qualité d'une image, par exemple un modèle imprimé
US5317390A (en) 1991-08-12 1994-05-31 Koenig & Bauer, Aktiengesellschaft Method for judging printing sheets
US5384859A (en) 1991-08-12 1995-01-24 Koenig & Bauer, Akteingesellschaft Method for quality control of printed sheets
EP0527285A2 (fr) 1991-08-12 1993-02-17 KOENIG & BAUER-ALBERT AKTIENGESELLSCHAFT Procédé pour juger la qualité de feuilles imprimées
EP0527453A1 (fr) 1991-08-14 1993-02-17 KOENIG & BAUER-ALBERT AKTIENGESELLSCHAFT Appareil pour contrôler des feuilles imprimés dans une machine rotative d'impression pour feuilles
EP0543281A1 (fr) 1991-11-21 1993-05-26 KOENIG & BAUER-ALBERT AKTIENGESELLSCHAFT Commande pour machines d'impression rotatives
EP0622191A1 (fr) 1993-04-30 1994-11-02 De La Rue Giori S.A. Dispositif d'essuyage d'une machine pour l'impression en taille-douce
EP0730959A1 (fr) 1995-03-07 1996-09-11 De La Rue Giori S.A. Procédé de production d'un modèle de référence destiné à être utilisé pour le contrÔle automatique de la qualité d'impression d'une image sur du papier
WO1997037329A1 (fr) 1996-04-02 1997-10-09 Koenig & Bauer-Albert Ag Procede et dispositif pour evaluer la qualite d'un materiau traite
WO1997048556A1 (fr) 1996-06-18 1997-12-24 Koenig & Bauer-Albert Ag Procede et dispositif d'evaluation qualitative de feuilles traitees
EP0820864A1 (fr) 1996-07-23 1998-01-28 Komori Corporation Appareil pour guider le papier dans une presse offset à imprimer des feuilles
EP0820865A1 (fr) 1996-07-25 1998-01-28 Komori Corporation Dispositif pour l'inspection de feuilles pour une presse offset à imprimer des feuilles
EP0873866A1 (fr) 1997-04-14 1998-10-28 De La Rue Giori S.A. Machine taille-douce
WO1999041082A1 (fr) 1998-02-13 1999-08-19 Koenig & Bauer Aktiengesellschaft Procedes et dispositifs pour transporter une feuille
EP0985531A1 (fr) 1998-09-07 2000-03-15 De La Rue Giori S.A. Inspection automatique de la qualité d'impression par un modèle élastique
EP1142712A1 (fr) 2000-04-07 2001-10-10 Komori Corporation Appareil pour contrôler la qualité d'une machine d'impression à retiration
EP1167034A2 (fr) 2000-06-23 2002-01-02 Komori Corporation Procédé et dispositif d'identification d'objets sous forme de feuilles
DE10132266A1 (de) * 2000-07-11 2002-01-24 Heidelberger Druckmasch Ag Verfahren und Vorrichtung zur Regelung des Übergabepassers in einer Bogenrotationsdruckmaschine
EP1190855A1 (fr) 2000-09-22 2002-03-27 Komori Corporation Appareil pour contrôler la qualité d'impression
EP1231057A1 (fr) 2001-02-09 2002-08-14 Komori Corporation Machine d'impression de feuilles
WO2002102595A1 (fr) 2001-06-15 2002-12-27 Koenig & Bauer Aktiengesellschaft Dispositif de controle de la qualite
EP1323529A1 (fr) 2001-12-27 2003-07-02 Komori Corporation Dispositif pour vérifier la qualité d'impression d'une machine à imprimer
WO2003070465A1 (fr) 2002-02-20 2003-08-28 Kba-Giori S.A. Dispositif de transport de feuilles equipe d'un element guide-feuille
DE10208285A1 (de) 2002-02-26 2003-09-18 Koenig & Bauer Ag Verfahren zur Korrektur der Bilddaten eines Kamerasystems
WO2003093011A1 (fr) 2002-05-06 2003-11-13 Kba-Giori S.A. Buses pour installation de nettoyage d'une machine a imprimer
WO2004017034A1 (fr) 2002-07-26 2004-02-26 Koenig & Bauer Aktiengesellschaft Procede pour analyser des divergences de couleur dans des images a l'aide d'un capteur d'image
DE202004018072U1 (de) * 2004-11-20 2005-01-20 Man Roland Druckmaschinen Ag Bogendruckmaschine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2461883C2 (ru) * 2007-10-02 2012-09-20 КБА-НотаСис СА Способ и система для контролируемого производства защищенных документов, в особенности банкнот

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