EP1857280B1 - Rotary printing press with at least one inking unit and one inline colour measuring system - Google Patents

Description

The invention relates to a rotary printing press with at least one inking unit and with an inline color measuring system according to the preamble of claim 1.

Not only in sheetfed printing, in which a transport speed of an arcuate printing material by a printing machine with this pressure is usually less than 5 m / s is relatively low, but also in web printing with a much higher transport speed of the web-shaped substrate here is the need to be in the printing press in particular to judge the quality of a printed product produced in multicolor. This assessment should preferably be carried out continuously in real time in a production of the printing press and, if possible, capture all copies of the printed product produced in the production process. In particular, the assessment relates to a visual color impression conveyed by the copies of the printed product in each case, in the way in which human visual perception perceives it. For a densitometric measurement of manufactured copies of the printed product is not sufficient, as z. B. by the US 6,983,695 B2 is known and is used for a regulation of the layer thickness of the inking to a control intervention on the inking unit of the printing press.

Also by the DE 40 04 056 A1 is a method for color control and zonal presetting of ink dosing elements in inking machines of rotary printing machines, in particular offset rotary printing machines, wherein printed images produced by the printing machine are scanned, for example densitometrically or colorimetrically, and the values obtained therefrom employing print carrier scanning logic with a self-learning system or with a so-called Expert system can be fed to a Farbbedarfermittlungsrechner, so that during a pressure and during a printing phase, the default values can be further specified on an ongoing basis.

Of the WO 2005/092613 A2 is a newspaper printing machine with a zonenweise color metering and an inline color measuring system removable, wherein the hue is detected spectrophotometrically, wherein the detection is carried out over the width of the printing material, wherein a plurality of sensors are provided, wherein the sensor can be configured as a photodiode and wherein the sensor recorded several shades. An illumination device may have pulsed or continuously operated light-emitting diodes or laser diodes. A control device, which receives data from a detection device having the sensors, has a high process speed.

By the EP 1 512 531 A1 a method and a device for controlling the coloration in a printing press are known, wherein a color recognition device is provided with a plurality of fixedly attached to the press color sensors for area-wide optical detection of the entire width of the printed product, wherein a fast primary color measurement signal per color zone is detected along the printing direction over a predeterminable color image area of the printed product is integrated, wherein the total actual area coverage is calculated for at least one ink, wherein a comparison with a target area coverage is carried out and wherein a color correction signal for the ink zone and the ink is generated. The color sensors may also be single diodes in a patterned photodiode. A structured photodiode typically comprises on a monolithic chip three individual diodes which can be read out via separate electrical connections and have color-selective spectral sensitivities by means of structured optical filters. The color sensor element may comprise one or more patterned photodiodes.

The EP 1 521 069 A2 relates to a photosensor for colorimetry based on three spectral components, for the detection of which a sensor chip has at least three sub-surfaces differently sensitive by an upstream interference filter structure, wherein the interference filter structure includes three different alternating layer systems of silicon dioxide and titanium dioxide for selectively transmitting incident light into the different subareas of the sensor chip, and provide the sub-areas measured values, wherein the photosensor has three covered with different matched to the spectral characteristic of the human eye interference filters faces, each arranged in a sector of a circle around a central point with intermediate passive webs, and each interference filter in a transmission characteristic over the wavelength of the spectral to Measuring light of the sensitivity of the human eye is adjusted so that the product from basic sensitivity of the photosensor and transmission of the interference filter is proportional to the normal spectral value curve of the human eye for the relevant coordinate of the color space, so that the transmitted spectral components in the sub-areas produce measured values which can be converted into spectral color values with one another in the color space with simple scaling.

The DE 32 20 093 A1 relates to a device for color density measurement on running, web-shaped printing materials with a plurality of sensors, which detect all measuring fields of printed color control strips simultaneously, wherein the measuring sensors are mounted transversely to the direction of the printing material slidably and in dependence on the lateral migration and / or the shrinkage of the Printing material to be adjusted.

By the EP 0 860 276 A1 is a device for performing quality management when printing with a web-fed rotary printing press with at least one adjustable over the width of the printing material measuring head known, the measuring head includes a spectrometer and an exposure source and means one of the web-fed rotary printing machine associated encoder can be activated depending on the product, with a control device, the measurement signals of each measuring head are continuously logged.

By the DE 197 03 129 A1 A method is known for evaluating the quality of a printed image produced in multicolor printing on a printing substrate, in which images are reproduced using an image recording device to derive color values from the signals for each printed image element in which the color values are transformed into colorimetric values of a given color space be determined in which for the print image elements color distances between an actual color location and a desired target color location, and in which a measure of the quality in at least one print image area is derived from the color distances, in which the color is controllable with at least one adjusting device , wherein are calculated and stored from the color differences manipulated variables of the adjusting devices, the effect on an actuator would bring a far-reaching approximation of the actual color locations to the respective target color locations, said as a measure of the quality in en print image area, the color distance vectors and color distances of at least one predetermined reference image are determined with homogeneous area coverage, the necessary to compensate for the color distances in the reference image control variables correspond to the previously calculated and stored control variables.

By the US 5 689 425 A A system is known for generating a signal representative of color registration offset between at least first and second colors of an image printed on a web, wherein a first printer unit prints the first color of the image and a second printer unit prints the second color of the image and wherein the system comprises: a) a memory arranged to store a first reference array of digital data representative of the first color of at least a portion of the image and a second reference array of digital data representative of the second color of the section; b) a Imaging apparatus in optical communication with the web for generating a first analog signal representative of the first color of the portion of the image and a second analog signal representative of the second color of the portion; c) an effectively associated with the imaging device converter circuit which converts the first analog signal into a first digital color signal and converts the second analog signal into a second digital color signal; and d) a processing circuit in exchange with the converter circuit and the memory, the processing circuit storing in the first memory a first array of color data at pressure generated by the first digital color signal and a second array of color data at pressure selected from the second digital color signal, and compares the first reference arrangement with the first array of color data when printed and compares the second reference array with the second array of color data when printed to determine an alignment offset between the first and second colors; generates the alignment offset between the colors representative signal.

By the DE 42 42 683 A1 For example, a method for controlling a color application of a printing unit is known wherein printing plates are input to the printing unit, wherein color values of the total inking after the printing unit are determined by a scanner, compared with target values and then inking control units are addressed.

By the DE 103 14 071 B3 is a method for the qualitative assessment of a material having at least one recognition feature known, wherein at least the detection feature a color image is taken with an electronic image sensor, wherein the image sensor directly or indirectly at least one correlated with the color image first electrical signal is provided, from at least one reference image a second electrical signal is obtained and stored in a data memory, wherein the second electrical signal at least one desired value for the first electrical Signal forms, and wherein at least the color image of the recognition feature on a color deviation from the reference image and / or the recognition feature on a membership of a certain class of recognition features and / or on a certain geometric contour and / or on a relative arrangement to at least one further recognition feature each of the material is checked by comparing the first signal with the second signal for reaching the target value or a match therewith.

An evaluation of the printed product based on the color impression is made on the basis of a spectral color measurement, to which the copies of the printed product are to be subjected. In this case, a color stimulus, which can be measured as light reflected by the printing material, is detected with an optical detection device and by means of further Tools in a color wheel, z. B. the CIELAB color wheel, or preferably in a color space, for. As the CIELAB color space shown. Handhelds for spectral color measurement, so-called spectrophotometers, are known. However, they are not suitable for use within a printing press, and certainly not for a data acquisition in a running printing process in real time. Likewise, inline inspection systems are known which are equipped with a camera system, eg. B. photograph with a line scan camera, a printed image produced by the printing press on the substrate. A camera-based in-line inspection system has the disadvantage that it generates huge amounts of image data, ie data volumes z. B. in the multi-digit GB area, which are evaluated in complex computerized image processing and evaluated, but inevitably requires a considerable amount of computing time.

A multi-color printing product producing web printing machine, z. As used in newspaper printing or commercial web presses, z. B. in an offset printing process, ie in a conventional wet offset printing process with a dampening solution used in the printing process or in a dry offset printing process without the use of a dampening solution, and thereby produces copies of the printed product z. B. with a related to a transport of the moving material in the printing press production speed in the range of 15 m / s to 20 m / s. Such a web-fed printing press can print cylinder, ie in particular cooperating form cylinder and transfer cylinder each with an axial length of z. B. up to 2,600 mm, wherein the scope of at least the respective forme cylinder z. B. in the range between 900 mm and 1300 mm. In such a web-fed printing machine, up to six printing forms can be arranged next to one another and in their respective circumferential direction, for example, at their respective form cylinders in their respective axial direction. B. in each case two printing plates can be arranged one behind the other. The respective printing plates are on the respective form cylinder z. B. held in the axial direction extending channels, wherein the channels on the lateral surface of the respective forme cylinder a slot-shaped opening with a slot width in the range z. B. from 1 mm to 3 mm.

In multi-color printing is involved in each of the printed image to be produced color separation, ie for each in one of the colors cyan, magenta, yellow or black to be printed part of the respective produced by a superimposition of these inks print image, usually a separate printing unit, the printing unit the Printing material at least on one side, preferably printed on both sides. A formed on the respective printing form subject is by means of one of the transfer cylinder on the formed in the web press as a web substrate, z. B. transferred to a paper web. At least according to the last printing in the direction of production of the successive printing presses arranged in the printing unit of the color impression resulting from the overprinting of the different color separations from the printed image on the copies of the printed product to be produced, each copy, z. B. every newspaper page produced should be completely detectable. At a production speed in the range of 15 m / s to 20 m / s usual today in newspaper printing or commercial printing, this means that a real-time evaluation of a complete page of each copy, e.g. B. the whole newspaper page, in terms of the respective mediated color impression in less than 50 ms, more in the range between 20 ms and 30 ms, must be completed and completed, in which case a directed in the circumferential direction of the respective forme length of the newspaper page in the area the half of the form cylinder circumference, ie in the range between 450 mm and 630 mm, was used. However, line scan cameras with a CCD chip as an image sensor, which has one or more rows of photosensitive pixels arranged parallel to one another, have hitherto had a line frequency of less than 60 kHz, in most cases even less than 10 kHz, for example. B. only about 7 kHz, which is at a directed in the direction of movement of the printing material pixel size in the range z. B. from 5 microns to 14 microns means that this line scan camera for use in one with an im Range of 15 m / s to 20 m / s producing printing machine is too slow to capture a print image either at all or at least without motion-induced distortions.

In particular, in newspaper printing are often used as complex printing presses with multiple sections are used, each section preferably has a plurality of printing towers, which in turn each in turn consist of several, z. B. consist of four stacked printing units. In such a printing system then several devices for assessing the quality of the copies of the printed product are required, at least for each printing tower at least one of these devices. In an examination printed on both sides of the paper web printed images are then required in each case two of these devices for each printing tower. From the large number of devices required for printing equipment to judge the quality of the copies of the printed product, there arises the requirement that such a quality-assessing device must be provided inexpensively in order to be marketable.

The invention has for its object to provide a rotary printing machine with at least one inking unit and with an inline color measurement system, a color location at discrete significant points in printed images produced by the rotary printing machine is reliably possible even in real time, when the rotary press the substrate with a Speed transported in the range of 15 m / s to 20 m / s.

The object is achieved by the features of claim 1.

The advantages that can be achieved with the invention are, in particular, that a color location determination at discrete significant points in printed images produced by the rotary printing machine is reliably possible even in real time, if the Rotary printing machine transported the substrate at a speed in the range of 15 m / s to 20 m / s. Also, a mounted on the substrate color bar is not required, as it is measured directly in the print image. The significant points can be selectively detected in a printed image for their respective assessment of the quality of their color impression, wherein with the colorimetrically obtained measurement result with respect to each measurement field, directly coordinates of a color location representable in a reference color space are provided. In an advantageous embodiment, significant points in a printed image for an assessment of the quality of their color impression in a clear assignment to the discrete color sensors they detect, which association preferably also persists in the printing process. In this embodiment variant, complicated arithmetic operations are dispensed with in a data processing unit located downstream of the data acquisition. Even for a production speed in the range of 15 m / s to 20 m / s, a suitable color measurement and color location determination for the assessment of the quality of the color impression of printed products, this solution is able to provide their respective measurement results in real time, if necessary, also to use the measurement results in a color control system which regulates at least one inking unit of the web-fed rotary printing press. Moreover, a complete color measurement can be performed on all produced copies of the printed product without thereby generating excessively large amounts of data.

An embodiment of the invention is illustrated in the drawings and will be described in more detail below.

Fig. 1

eine Anordnung von Messbalken eines Inline-Farbmesssystems in einer Rollenrotationsdruckmaschine;

Fig. 2

einen Messbalken mit mehreren Farbsensoren und mehreren Lichtquellen;

Fig. 3

ein Diagramm mit einem Verlauf einer Spektralfunktion für lichtempfindliche Bereiche eines Farbsensors;

Fig. 4

in einem Blockschaltbild eine Messanordnung mit nachgelagerter Datenverarbeitung;

Fig. 5

eine Messfläche mit selektiv erfassbaren Messfeldern;

Fig. 6

eine zur lateralen Nachführung des Messbalkens verwendbare Marke;

Fig. 7

eine weitere Ausführungsform der zur lateralen Nachführung des Messbalkens verwendbaren Marke.

Show it:

Fig. 1

an array of measuring bars of an in-line color measuring system in a web-fed rotary printing press;

Fig. 2

a measurement bar with multiple color sensors and multiple light sources;

Fig. 3

a diagram with a profile of a spectral function for photosensitive areas of a color sensor;

Fig. 4

in a block diagram, a measuring arrangement with downstream data processing;

Fig. 5

a measuring surface with selectively detectable measuring fields;

Fig. 6

a mark which can be used for the lateral tracking of the measuring beam;

Fig. 7

a further embodiment of the usable for the lateral tracking of the measuring beam mark.

Fig. 1 shows schematically an arrangement of two measuring bars 01; 02 one in a rotary printing machine, z. B. a web-fed rotary printing press, arranged inline color measuring system, wherein each a measuring beam 01; 02 on one of the surfaces of a transported by the rotary printing press substrate 03, z. B. a flat substrate web 03, preferably a paper web 03, is directed. The respective at least one arrangement of sensor elements 11; 12 having measuring bar 01; 02, wherein the arrangement of the sensor elements 11; 12 each z. B. as a color sensor 11; 12 is formed, for reasons of mechanical stabilization of one of the respective color sensors 11; 12 to be scanned on the respective surface of the printing substrate 03 measuring surface 28 ( Fig. 5 ) preferably arranged on or at least near a deflecting roller 08 deflecting the printing material web 03, ie either above this deflecting roller 08 or shortly thereafter, which means that the measuring surface 28 on the respective surface of the printing material web 03 at the time of scanning a distance c until the deflection of the printing substrate 03 z. For example, less than 1 m. The in the measuring beam 01; 02 each rigid, ie stationary sensor elements 11; 12, z. B. the color sensors 11; 12, are each with their respective directed to the surface of the printing substrate 03 photosensitive active surface at a distance a; b of a few millimeters, z. B. from 5 mm to 10 mm to the measuring surface 28 on the respective surface of the printing substrate 03. The deflection roller 08 may be formed by a roller arranged in the superstructure of the web-fed rotary printing press.

The printing substrate 03 has within the web-fed rotary printing press a transport speed in the range z. B. from 15 m / s to 20 m / s, preferably between 17 m / s and 20 m / s. The web-fed rotary printing press is z. B. as one working in a newspaper printing or in a commercial printing, each z. B. in a gravure printing process or in a planographic printing process, preferably in an offset printing process printing web-fed rotary printing machine. A printing unit 04 of the web-fed rotary printing press is in the Fig. 1 greatly simplified only by two mutually employed printing cylinder 06; 07 indicated, wherein the printing substrate 03 between the two mutually employed printing cylinders 06; 07 is passed. It is understood that belong to the printing unit 04 more, not shown components; z. B. is at least each of a respective color separation of a printed image to be printed on the respective surface of the printing substrate 03 printing cylinder 06; 07 in each case with a for the printing process each providing a printing ink in operative connection.

The web-fed rotary printing press preferably has a plurality, for. B. four in the transport direction of the printing substrate 03 successively arranged printing units 04, wherein in each printing unit 04 one of the participating printed image color separations is printed, each of these superimposed to be printed color separations with one of the printed inks. In multicolor printing in particular the printing inks cyan, magenta, yellow are common, and in addition even the printing ink black is used. With each of these inks, a part of the print image to be produced is printed in each case, ie each of the color separations provides its contribution to the color structure of the printed image. The measuring bars 01; 02 of the arranged in the web-fed rotary printing press inline color measuring system are preferably after the last of each other in the transport direction of the printing substrate 03 successively arranged printing units 04, ie after the successful overprinting of all involved in the printed image color separations respectively inks arranged.

At least one of the one of the printing cylinder 06; 07 associated inking units has several in the axial direction of the printing cylinder 06; 07 juxtaposed color zones, z. B. between 30 and 60 ink zones, each with an actuating element individually and independently with respect to a provided in the respective ink zone amount of ink, in particular a layer thickness of the ink, preferably by a z. B. at a belonging to the web-fed rotary press control unit remote control can be adjusted. The ink zones are usually in their respective axial direction of the printing cylinder 06; 07 directed width and immutable. After being transferred to the surface of the printing substrate 03 on the surface of the printing substrate 03, the ink provided in each of the ink zones generates a color strip extending in the transport direction of the printing substrate 03 having a width e corresponding to the width of the respective ink zone, the width e of the color stripes z. B. between 30 mm and 60 mm, preferably between 40 mm and 50 mm ( Fig. 2 ).

Fig. 2 shows a section of one of the transverse to the transport direction of the printing substrate 03 arranged measuring beam 01; 02 of the arranged in the web-fed rotary printing machine inline color measuring system ( Fig. 1 ), preferably each measuring beam 01; 02 extends over at least the entire width B of the printing substrate 03 ( Fig. 5 ). In the measuring bar 01; 02 are in a row z. B. a plurality of color sensors 11; 12 discrete, ie spaced from each other at a distance d. The in the measuring beam 01; 02 arranged in a row color sensors 11; 12 are each formed as separate components and can each be arranged equidistantly. In the measuring bar 01; 02 are also preferably provided in a row a plurality of discrete light sources 13, wherein the light sources 13 z. B. each as a light emitting diode 13 or as a laser diode 13 and optionally a z. B. may have controlled by a temperature control device cooling. The light sources 13 are preferably formed as a white light source 13 and in their respective spectral behavior z. B. approximated in each case by the CIE specified standard light D50 or D65. The row of light sources 13 is connected to the row of color sensors 11; 12 z. B. arranged in parallel, wherein the two rows from one another in the transport direction of the printing substrate 03 extending distance f each emanating from their centers of z. B. a few millimeters to a few centimeters. Each of the color sensors 11; 12 are z. B. associated with one or more light sources 13, so that each color sensor 11; 12 together with its associated at least one light source 13 each forms a preferably independently usable, at least functionally separate assembly. Each of the printed on the surface of the printing substrate 03 color strip with the width e are preferably more of the arranged in the same row color sensors 11; 12 and preferably associated with a plurality of light sources 13 arranged in the same row. A boundary line between adjacent color stripes is in the Fig. 2 each indicated by a dashed line. It is advantageous, in the measuring beam 01; 02 arranged color sensors 11; 12 in each case by opaque walls (not shown) against each other foreclose to avoid interference effects by light, which is not of a respective color sensor 11; 12 associated measuring field 29 of the measuring surface 28 ( Fig. 5 ) is reflected. The partitioning of the individual color sensors 11; 12 thus serves the avoidance, but at least a significant reduction of unwanted external light detection. Each of the color sensors 11; 12 preferably has its own housing, which at least the photosensitive active surface of the respective Color sensor 11; 12 borders. The color sensor 11; 12 and its associated at least one light source 13 existing assembly is preferably on the same support, for. As an electrical circuit board arranged. An alternative embodiment may provide the individual sensor elements 11; Form 12 as individually readable pixels of a CMOS image sensor, wherein the individual pixels or groups of pixels are each assigned specific color filter. In contrast to a CCD image sensor, in which only entire rows of pixels can be read out, in the case of a CMOS image sensor, the pixels arranged in rows or in a surface array can be individually read out.

The measuring bars 01; 02 are in their arrangement transversely to the transport direction of the printing substrate 03 preferably displaced and z. B. with respect to a changing position in their edge 37 of the printing substrate 03 trackable. The lateral tracking of the respective measuring beam 01; 02 can take place with respect to the edge 37 of the printing substrate 03 also with respect to a printed image permanently assigned brand 37, which can be arranged on the surface of the printing material 03 inside or outside of the printed image for the lateral position of the print image a reference forming mark 37. This mark 37 may be formed as a registration mark 37 printed on the surface of the printing substrate 03 together with the respective printed image. However, the mark 37 can also be a distinctive element of the respective print image and be different for different print jobs, so that a print job-related definition has to be made, which is necessary for the lateral tracking of the respective measuring beam 01; 02 is to be registered as mark 37. The brand 37 is in any case in a fixed relationship with the surface of the substrate 03, so based on a z. B. to the stationary printing cylinders 06; 07 and / or their printing plates relative change in location of the brand 37 a lateral positional offset of the printing substrate 03 is detectable. The mark 37 is preferably detected with a position sensor 38, wherein the position sensor 38 z. B. may be formed as an image sensor 38. The image sensor 38 may be a line CCD or a Have face CCD or be formed in CMOS technology. In the case of detecting an in the printing process in their position changing edge 37 of the printing substrate 03 of the position sensor 38 z. B. formed as a side edge sensor 38, wherein the side edge sensor 38 z. B. is designed in the form of a fork light barrier. The position sensor 38 is preferably in its respective lateral position, ie in its parallel to the respective measuring beam 01; 02 extending position adjustable and preferably along a traverse preferably independent of the respective measuring beam 01; 02 slidably arranged.

The lateral tracking of the respective measuring beam 01; 02 is controlled or regulated with the aid of an output signal of the respective position sensor 38 evaluating control unit 39, so that in the printing process of the measuring beam 01; 02 is always taken with respect to the printing substrate 03 optimal transverse position. The lateral position is then considered optimal if, with the in the measuring beam 01; 02 arranged discrete color sensors 11; 12 specific significant locations in the printed image in a unique assignment of each of these locations to exactly one of the color sensors 11; 12 are fully comprehensible. In particular, by the lateral tracking of the measuring beam 01; 02 whose in the respective measuring beam 01; 02 fixedly arranged color sensors 11; 12 brought into coincidence with the extending in the transport direction of the printing substrate 03 color stripes in a clear assignment. The transverse to the transport direction of the printing substrate 03 directed, lateral travel s of the measuring beam 01; 02 is for their respective tracking each z. B. only a few millimeters, z. B. up to 10 mm, which is usually sufficient to compensate for a possible shift in the printing process of the mark 37 or edge 37 of the printing substrate 03. The tracking of the measuring bars 01; 02 is preferably carried out dynamically as a function of the respective positional offset of the mark 37 or edge 37 of the printing material web 03 detected by the respective position sensor 38. The measuring beam 01; 02 is along its lateral travel s with a z. B. operated by the control unit 39 or remotely operated drive 36 z. B. adjusted by means of a pull rod or a push rod and brought into its optimal transverse position.

In the respective measuring bar 01; 02 arranged color sensors 11; 12 are each z. B. formed as a so-called analog tristimulus sensors, ie, the color sensors 11; 12 are each as a on its respective effective area in each case three discrete photosensitive areas having color sensor 11; 12 formed. The three discrete photosensitive areas each have a different spectral sensitivity, each color sensor 11; 12 as its respective output signal each provides a value triplet, each value triplet a measured value x; y; z from each of the three discrete photosensitive areas, the measurements constituting the respective value triplets x; y; z are recorded simultaneously. A course of a spectral function for each of the three discrete photosensitive areas of each of the color sensors 11; 12 is exemplary in the Fig. 3 shown in a diagram, wherein a relative radiation energy I over the wavelength λ of the respective color sensor 11; 12 is applied detectable light, wherein the specified wavelength range covers the detectable by the human eye spectral range of λ = 380 nm to λ = 780 nm. The spectral function curves are shown for a viewing angle of 2 ° in the form of a solid line and for an observation angle of 10 ° in the form of a dashed line. The three measured values x; y; z of the value triplet form in each case coordinates of a color locus which can be represented in a reference color circle or in a reference color space, so that the color sensors 11; 12 are suitable for direct color location measurement, because they correspond to the z. B. in DIN 5033 or normalized according to CIE 1931 normal spectral value function. The respective output signal of the color sensors 11; 12 therefore does not form an RGB signal, which would be subjected to further transformations if one wanted to determine a color location with the RGB signal. Alternatively, the three discrete photosensitive areas may also be in association with pixels of a multi-pixel CMOS image sensor, these pixels each with corresponding color filters cooperate to be sensitive to a selected spectral range. Thus, in each case a part of the pixels, ie the sensor elements 11; 12 of the respective CMOS image sensor, each associated with one of three discrete photosensitive areas. The measured values x; y; z of three common and preferably simultaneously read pixels of the CMOS image sensor, these three pixels having differently colored color filters, form in analogy to the output signal of the discrete color sensors 11; 12 the value triplet from which the coordinates of a color locus that can be displayed in a reference color space or in a reference color space are determined.

Fig. 4 shows in a block diagram by way of example a plurality of juxtaposed color sensors 11; 12 with their respective associated light source 13, the light sources 13 send their light as a continuous light or in the form of light pulses each on the surface of the printing substrate 03, wherein the surface of the printing substrate 03 remitted a portion of this light, wherein a portion of the remitted light on the effective area of at least one of the color sensors 11; 12 and is detected there ( Fig. 1 ). The light path is in the Fig. 1 and 4 each indicated by arrows. The light sources 13 send their light at an angle z. B. of 45 ° each on the surface of the printing substrate 03, whereas a measuring axis of the color sensors 11; 12 z. B. is perpendicular to the surface of the printing substrate 03.

The respective value triplet with the measured values x; y; z becomes z. B. a measured value amplifier 14, which receives this output signal z. B. the respective color sensor 11; 12 amplified by a gain factor, wherein the gain factor for the respective output signal is preferably from each of the arranged in the same row of color sensors 11; 12 is parameterized differently and if necessary, at least several of these gain factors are also parameterized differently. Thereafter, the analog output signal of the respective color sensor 11; 12 to an A / D converter 16 which supplies the optionally previously amplified output signal of the respective Color sensor 11; 12 digitized and thus in a z. B. 12-bit digital value, this digital value preferably the whole of the value triplet with the measured values x; y; z contains resulting color location information.

In a z. As an FPGA (field programmable gate array), i. H. in a first control unit 17 embodied as a freely programmable logic circuit, the color sensors 11; 12 generated digital values and filtered according to predetermined and / or set criteria. A clocking 19 of the A / D converter 16 can be controlled by this control unit 17. Also, this control unit 17 optionally via an amplifier 18 to each color sensor 11; 12 each associated with at least one light source 13 drive.

It may be another, second, preferably also z. B. designed as a FPGA control unit 21 may be provided which the detected, from the color sensors 11; 12 evaluates generated digital values and, if necessary, provides for a data transfer. The data transfer can z. B. via a local communication network 22 z. B. done according to the Ethernet technology. However, the data transfer can also z. B. continue over the Internet. The z. B. via the local communication network 22 data transfer can serve the purpose, evaluated by the color sensors 11; 12 archived digital values in a data memory 23 to archive. The second control unit 21 may also include a data memory 27 for storing parameters, e.g. The functions of the first control unit 17 and the second control unit 21 may also be structurally combined in a single, preferably electronic data processing unit, this data processing unit being connected to the color sensors 11; 12 data collection is downstream.

Preferably, a z. B. with one of the printing cylinder 06; 07 in Functional connection standing encoder 24 is provided, which the transport speed of the transported by the web-fed rotary printing machine, on the at least one measuring beam 01; 02 vorbei led tracing material 03 detects, with a generated by the encoder 24, with the transport speed of the printing substrate 03 corresponding signal z. B. via a synchronizer 26, the control units 17; 21 is supplied to the detection of the color sensors 11; 12 synchronized digital values with the movement of the printing substrate 03 to synchronize. This is then also a tap of the respective output signal of the respective measuring beam 01; 02 each arranged in the same row sensor elements 11; 12 synchronized with the transport speed of the printing substrate 03. The encoder 24 generates z. B. with each complete revolution of standing in operative connection with him printing cylinder 06; 07 a zero pulse. If the printing cylinder 06; 07 in its axial direction at least one channel z. B. for holding at least one on the printing cylinder 06; 07 mounted elevator, z. As the at least one mounted on the forme cylinder printing form, then this channel can be used to generate the zero pulse of the encoder 24.

The in the Fig. 4 dashed lines shown functional units such. B. color sensors 11; 12, measuring amplifier 14, light sources 13 and amplifier 18 can different measuring beam 01; 02, so that it is indicated that in the illustrated example on both sides of the printing substrate 03 each have at least one row of color sensors 11; 12 and light sources 13 are arranged, wherein the respective output signal of all belonging to the same inline color measuring system color sensors 11; 12 preferably from the same control units 17; 21 is recorded and evaluated.

Fig. 5 1 shows a measuring surface 28 defined with respect to one of the surfaces of the printing material web 03, wherein this measuring surface 28 extends over the entire width B of the printing material web 03 oriented transversely to the transport direction of the printing substrate web 03 and wherein this measuring surface 28 in the transport direction of the printing substrate web 03 has a section length L, wherein the section length L z. B. with the circumferential direction of the respective printing cylinder 06; 07 directed length of a newspaper page corresponds and thus z. B. in the range of half the circumference of the respective printing cylinder 06; 07, ie in the range between 450 mm and 630 mm. The width B of the printing substrate 03 can be up to the axial length of the printing cylinder 06; 07 amount and thus z. B. have a width B up to 2,600 mm. The width B of the printing substrate 03 is in particular in the range of 1,000 mm to 2,600 mm. Along the width B of the printing substrate 03 are in the axial direction of the printing cylinder 06; 07 next to each other z. B. four or six print images of z. B. to be printed newspaper pages arranged, each print image can correspond with a mounted on a forme cylinder printing form.

In a running printing process, as far as possible all the printed images produced are recorded, so that the hue of the ink applied to the respective surface of the printing substrate 03 in a plurality of successive, synchronized with the transport speed of the printing substrate 03 measurements within each measuring surface 28 at different discrete measuring positions, ie is detected substantially point by point. In conjunction with the output signal of the encoder 24, each measurement of the respective measuring beam 01; 02 fixedly arranged color sensors 11; 12 by linking a color sensor 11 performing the measurement; 12 related location information with a by means of the encoder 24 obtained, related to a particular section of the printing substrate 03 information associated with a particular print image, so that a printed copy related logging of the measurement results is possible. To carry out the printed copy related logging of the measurement results, the encoder 24 passes z. B. from pulses output signal to a production counter 41, wherein in the production counter 41 an assignment of z. B. a certain number of pulses of the encoder 24 to a specific, directed in the transport direction of the printing substrate 03 section length of each Print copy is set, wherein in the production counter 41 after each reaching the correlated with the section length of the printed copy, certain number of pulses of the encoder 24, a count is incremented, the count z. B. to the data memory 23 ( Fig. 4 ), in which of the color sensors 11; 12 generated digital values is transmitted to there in a fixed relation with those of the color sensors 11; 12 generated digital values to be stored. In addition or as an alternative to the data memory 23, the production counter 41 can also send the counter reading determined by it with regard to a specific production to one of the control units 17; 21 and thus z. B. lead to the data memory 27, which in the Fig. 4 is indicated by a dashed line connection line. By using a production counter, a measurement result and an associated quality assessment can be unambiguously assigned to a specific print image.

Along the width B of the printing substrate 03 are adjacent to each other, z. B. between 30 and 60 color strips arranged with a width e, wherein the width e of the respective color strip corresponds in each case with a color zone of the ink supplying the respective inking. Along the width B of the printing substrate 03 and thus also in the axial direction of the printing cylinder 06; 07 adjacent color strips preferably each have the same width e. The measuring surface 28 is thus subdivided into a measuring grid, wherein the color strips each define columns of the measuring surface 28, which are subdivided along the transport direction of the printing material 03 extending section length L into a plurality of individual juxtaposed measuring fields 29. Along the width B of the printing substrate 03 juxtaposed measuring fields 29 form a row of the measuring surface 28. The individual measuring fields 29 are each preferably rectangular, z. B. square formed; However, they can also be circular in each case. Each column of the measuring surface 28 may also have a plurality of juxtaposed measuring fields 29 per line, so that each color strip is subdivided into a plurality of measuring fields 29 in its width e. Each preferably each square-shaped Measuring field 29 has a size in the range z. B. from 1 x 1 mm ² to 5 x 5 mm ² , preferably between 2 x 2 mm ² and 3 x 3 mm ² . The measuring fields 29 are thus considerably larger than an area of the respective raster points formed on the surface of the printing substrate web 03 by the inking, wherein the raster dots have a planar extent in the range of less than 0.2 mm. Each of the measuring fields 29 defines a measuring position within the measuring surface 28. Each measuring field 29 can form a section of the printed image printed on the printing substrate 03.

A transversely to the transport direction of the printing substrate 03 arranged measuring beam 01; 02 detects with its sensor elements 11; 12 in each case the hue of the applied to the surface of the printing substrate 03 ink, ie, the sensor elements 11; 12 deliver a measured value x; y; z, from which the data processing unit determines, with respect to a selected measuring position within the measuring surface 28, the associated color locus in a color wheel or in a color space, wherein for detecting the color tone of measuring fields 29 arranged in the same column of the measuring surface 28, specific sensor elements 11 arranged in each case are arranged ; 12 are provided. In an advantageous embodiment, along the width B of the printing material web 03 side by side as many measuring fields 29 are defined as in the respective measuring beam 01; 02 z. B. color sensors 11; 12 are arranged side by side in the same row. When the measuring bar 01; 02 less parallel to each other arranged rows of sensor elements 11; 12, which are arranged transversely to the transport direction of the printing substrate 03 adjacent to each other in a row, are provided as rows of measuring fields 29 in the measuring surface 28, the successively arranged in a column in the transport direction of the printing substrate 03 measuring fields 29 of the measuring surface 28 sequentially in recorded several synchronized with the transport speed of the printing substrate 03 measurements. All arranged in the same row of the measuring surface 28 measuring fields 29 are of the respective measuring beam 01; 02 arranged sensor elements 11; 12 simultaneously detectable. The measured value processing and measured value evaluation following the measured value acquisition takes place isochronous to Data acquisition. The respective measuring bars 01; 02 be laterally tracked in particular in an oblique or laterally offset inlet of the printing substrate 03 in the printing unit 04 to the fixed relation of each sensor element 11; 12 to maintain a particular measuring field 29 of the measuring surface 28, wherein for the tracking of the respective measuring beam 01; 02 required travel s continuously or stepwise in steps with a step size of z. B. one tenth of the respective transversely directed to the transport direction of the printing substrate 03 measuring field width, ie, for example, in steps with a step size in the range between 0.1 mm and 0.5 mm, is executed. To compensate for lateral fluctuations of the printing substrate 03, so it is preferably provided that the sensor elements 11; 12 are traceable transversely to the transport direction of the printing substrate 03 with their respective respective perpendicular with their photosensitive area measuring axis, this tracking is dependent on a change in the printing material 03 firmly associated brand 37 with respect to their lateral position.

For lateral tracking of the respective measuring beam 01; 02, a mark 37 can be used, as exemplified by the 6 and 7 demonstrate. The applied on the surface of the printing substrate 03 and detected by the position sensor 38 mark 37 is z. B. wedge-shaped, preferably formed as a right triangle with a directed in the transport direction of the printing substrate 03 tip ( Fig. 6 ), wherein the transversely to the transport direction of the printing substrate 03 directed maximum extent of the mark 37, ie the transverse to the transport direction of the printing substrate 03 directed towards the triangle of the triangle preferably from the respective measuring beam 01; 02 corresponds to its tracking maximally executable travel s. According to the Fig. 7 the mark 37 is designed as a stepped element.

It is one of the particular advantages of the proposed solution that the output signal of one of the series of sensor elements 11; 12 arbitrarily arranged individual sensor element 11; 12 z. B. of the first control unit 17 selectively can be tapped. Also, several in the same row of the sensor elements 11; 12 arbitrarily arranged sensor elements 11; 12 are selected, the respective output signal z. B. is tapped by the first control unit 17 each simultaneously selectively. Thus, in each row of the measuring surface 28, individual, arbitrarily arranged discrete measuring fields 29, ie measuring positions, selectable, whose respective hue of one of the in one of the measuring bars 01; 02 arranged sensor elements 11; 12 is detected. Within the measuring surface 28 selectively detected measuring fields 29 are in the Fig. 5 each indicated by a gray circle, wherein the position of each gray circle each with a preferably vertically arranged above the respective gray circle active surface of the sensor elements 11; 12 correlates, which in particular when using discrete color sensors 11; 12 is advantageous.

Each measurement carried out in one of the measuring fields 29 combines the color stimulus generated by the screen dots applied in this measuring field 29 into a single color tone, the color of which is determined in a standardized color wheel, for example a color code. B. the CIELAB color wheel, or preferably in a standardized color space, for. B. the CIELAB color space, displayable color location is given by coordinates, which in a direct context z. B. with the of the three photosensitive areas of the respective color sensor 11; 12 simultaneously generated, as an output signal of this color sensor 11; 12 measured values x each forming a value triplet; y; z correspond. In the case of using a CMOS image sensor, the measured value x; y; z from the respective output signal of three pixels together, these pixels being a group of sensor elements 11; 12, in which group at least one pixel is assigned to each of the three discrete photosensitive areas.

For example, from a pre-printing stage 31 upstream of the actual printing process, significant locations are known for each printed image of the printed product to be produced which are particularly relevant for an assessment of the quality of the color impression. One of these significant points can z. B. a solid surface, a Gray balance field or a technical grid in the respective print image to be printed. Likewise, significant digits may be those locations of the print image between which a maximum color space spacing exists. The significant digits known as determining the quality for a specific print image can be effected by means of a special intelligent evaluation algorithm, ie in terms of programming, or by an assignment by an operator of the rotary printing press. This assignment by an operator may, for. Example by means of an input element to a monitor of a web-fed rotary printing press belonging control station. Each significant location preferably corresponds to exactly one of the measurement fields 29 of the measurement area 28.

On the basis of these significant points, a filter is defined with regard to the measuring surface 28, which determines relevant measuring fields 29 in each of its rows and / or columns for a specific print image to be printed in the measuring surface 28. This filter is from the prepress 31 z. B. transmitted via the communication network 22 to the inline color measuring system belonging to the first control unit 17 and / or second control unit 21, wherein based on this filter z. B. from the first control unit 17, the tap of the respective output signal z. B. that color sensor 11; 12 in the respective measuring beam 01; 02 is selected, which detects the hue from the corresponding with the significant point in the printed image measuring field 29. Based on the preferably programmatically designed filter for each line of the measuring surface 28 z. B. those color sensors 11; 12 whose measured values x; y; z are really relevant to the assessment of the quality of the color impression. Thus, the filter makes a selection of at least one of the color sensors 11; 12 with regard to at least one significant point of the printed image. By the line by line selection of color sensors 11; 12 arises with respect to the measuring surface 28 a tapping pattern, as it Fig. 5 exemplarily shows. Thus, the respective output signal of a plurality of color sensors 11; 12 detectable by the data processing unit, wherein the data processing unit based on the set and preferably in her stored filter at least one of the color sensors 11; 12 selects and only the output of the selected color sensor 11; 12 or only the respective output signal of the selected color sensors 11; 12 recorded.

Due to the pre-selection of only really relevant measuring fields 29 with regard to the printed image to be assessed, the acquisition of a large amount of data is avoided with only a few data relevant to the assessment of the quality of the color impression, which is a clear advantage over z. B. a line scan camera with a CCD chip as an image sensor. Because a CCD chip also has z. B. in a row juxtaposed photosensitive pixels, but these pixels are only read line by line and not pixelelective. Thus, a line scan camera with a CCD chip provides a very large amount of data, which has to be filtered for relevant image data following its detection by complex arithmetic operations, which takes some time due to the large amount of data collected, until relevant to the assessment of the quality of the color impression Measurement result is available.

According to the proposed solution, the color separations involved in the printed image to be produced, ie for the parts to be printed in one of the printing inks cyan, magenta, yellow or black, of the respective printed image to be produced by overprinting these inks Fig. 5 with respect to the pre-press 31 represented by the letters C (cyan), M (magenta), Y (yellow) or K (black), subjected to image analysis 32, significant digits in the print image being evaluated and evaluated in an image analysis 32 Selection unit 33 are extracted, whereupon in a measuring screen generator 34, the filter for selecting those color sensors 11; 12 is generated, the respective output signal then z. B. synchronized by the first control unit 17 at a certain production process with the transport speed of the printing substrate 03 are tapped.

Since the proposed solution for all significant points of a printed image without the measured value acquisition provides a time-consuming arithmetic operations a measurement result which is directly suitable for assessing the quality of the color impression of this printed image, this assessment of the quality of the color impression can also at a transport speed of the moving through the web-fed printing press substrate 03 in the area z. B. from 15 m / s to 20 m / s in real time.

The determined from data of the prepress 31 filter is determined separately for each print image to be printed and set separately in the inline color measurement system for each print image to be printed, bringing a print image individual selection of those color sensors 11; 12 results, the respective output signal z. B. be tapped by the first control unit 17 in a particular production process. Thus, a copy of the quality of the color impression of each printed image, which is carried out on the basis of individual significant points, is possible with exact copy accuracy. The recorded for each printed image at its significant points measurement results can be used for the purpose of their archiving in the z. B. stored on the communication network 22 with the inline color measurement system data storage 23 and used as a copy accurate proof of the quality of the color impression of the printed images of the printed product produced. The copy proof for the quality of the color impression of the printed images of the printed product produced is particularly possible if z. B. in conjunction with the encoder 24, a production counter 41 is provided so that measurement data can be assigned copy-accurate. Moreover, it can be provided that, in a further processing downstream of the printing process, separated printed copies which do not correspond to the required quality are ejected copy-accurate by a copy-related control of a waste paper sluice.

It can be provided that the inline color measuring system with its measuring beam 01; 02 Part of a color control system, which in each case controls a dosage of the ink at at least one, preferably at each belonging to the web-fed rotary printing unit, preferably for all ink zones of the respective inking unit. For this purpose, it may be provided that this is done on the selected color sensors 11; 12 each tapped output each with a z. B. provided by the prepress 31, corresponding setpoint is compared in a comparison unit, wherein at a deviation of the z. B. with the color sensors 11; 12 detected measurement result of the predetermined setpoint value, ie at an undesirable, a predetermined tolerance limit exceeding the color locus deviation .DELTA.E z. B. of .DELTA.E.gtoreq.2, in the relevant inking unit by means of the control element provided for each inking zone, a control intervention is made with the proviso of minimizing the deviation determined. As an alternative to provided by the prepress 31 target values, these can also be from a z. B. read in by the inline color measurement system Gutzustand be already located in the production printing images derived, with z. B. a plurality of similar printed images of the inline color measurement system are preferably subjected to a full color measurement, with respect to these printed images from the measured values respectively corresponding measuring fields 29 an average value is formed, which is then set as a setpoint for comparison with subsequently acquired measured values. In this case, a filter algorithm identifies the metrologically relevant points in the print image, ie the respective measurement positions, and preferably automatically generates the filter for selecting those sensor elements 11; 12, the respective output signal for an assessment of the quality of the color impression subsequently produced printed images are tapped.

LIST OF REFERENCE NUMBERS

01

measuring beam

02

measuring beam

03

Substrate, substrate web, paper web

04

printing unit

05

-

06

Printing cylinders

07

Printing cylinders

08

idler pulley

09

-

10

-

11

Sensor element, color sensor

12

Sensor element, color sensor

13

Light source, LED, laser diode, white light source

14

Measuring amplifier

15

-

16

A / D converter

17

control unit

18

amplifier

19

clocking

20

-

21

control unit

22

Communication network

23

data storage

24

encoder

25

-

26

synchronizing

27

data storage

28

measuring surface

29

measuring field

30

-

31

prepress

32

image analysis

33

Evaluation and selection unit

34

Measuring grid generator

35

-

36

drive

37

Edge, mark

38

Position sensor, image sensor, side-edge sensor

39

control unit

40

-

41

Pedometers

a

distance

b

distance

c

distance

d

distance

e

distance

f

distance

s

Travel Range

x

reading

y

reading

z

reading

B

Width (03)

L

Section length (28)

I

relative radiant energy

λ

wavelength

Claims (40)

1. An offset printing machine with at least one inking unit and with an inline colour measuring system, whereby the at least one inking unit provides a printing ink for printing a printed image onto a print substrate (03), whereby the inline colour measuring system has at least one arrangement of several sensor elements (11; 12), whereby this arrangement has three discrete light-sensitive areas, whereby each of the three discrete light-sensitive areas is in each case assigned at least one sensor element (11; 12), whereby the arrangement of sensor elements (11; 12) at at least one discrete measuring position in the printed image printed onto the print substrate (03) in all three discrete light-sensitive areas in each case acquires a measured value (x; y; z), whereby a data-processing unit determines a colour coordinate from these measured values (x; y; z) acquired at the respective measuring position in a colour wheel or in a colour space, characterised in that several arrangements of sensor elements (11; 12) are provided, whereby the arrangements of sensor elements (11; 12) are arranged in at least one row extending transversely to a direction of transport of the print substrate (03), whereby the respective arrangement of sensor elements (11; 12) in each case is configured as a colour sensor (11; 12), whereby the colour sensors (11; 12) are arranged rigidly in a measurement bar (01; 02) belonging to the inline colour measuring system, arranged transversely to the direction of transport of the print substrate (03) in each case, whereby each of the colour sensors (11; 12) acquires the hue of a selected measuring field (29), whereby the measuring field (29) is a constituent of a measuring surface (28) defined with respect to the surface of the print substrate (03), whereby along a width (B) of this print substrate (03) oriented transversely to the direction of transport of the print substrate (03) juxtaposed measuring fields (29) form a line of the measuring surfaces (28), whereby the respective measuring position of the colour sensors (11; 12) is selected by the data-processing unit by means of a programmatically set filter, whereby the data-processing unit acquires the respective output signal of several of these colour sensors (11; 12), whereby the data-processing unit selects at least one of the colour sensors (11; 12) by means of the filter set in it and acquires only the output signal of the selected colour sensor (11; 12) or only the respective output signal of the selected colour sensors (11; 12), whereby the filter for a specific image to be printed determines relevant measuring fields (29) in the measuring surface (28) in each of its lines in each case, whereby those colour sensors (11; 12) are selected by means of the programmatically configured filter for each line of the measuring surface (28), the measured values (x; y; z) of which are relevant with respect to assessing the quality of the colour impression.
2. The offset printing machine as claimed in Claim 1, characterised in that the three discrete light-sensitive areas in each case have a differing spectral sensitivity.
3. The offset printing machine as claimed in Claim 1, characterised in that the arrangement of sensor elements (11; 12) prepares a value triplet as its respective output signal, whereby the value triplet from each of the three discrete light-sensitive areas in each case contains a measured value (x; y; z).
4. The offset printing machine as claimed in Claim 1, characterised in that the arrangement of sensor elements (11; 12) acquires the measured values (containing x; y; z) in its output signal at the same time.
5. The offset printing machine as claimed in Claim 1, characterised in that the three measured values (x; y; z) in each case are a standard colour value which can be shown in a colour wheel or colour space.
6. The offset printing machine as claimed in Claim 1, characterised in that a measurement amplifier intensifies (14) the respective measured values (x; y; z) of the sensor elements (11; 12) with a gain factor.
7. The offset printing machine as claimed in Claim 6, characterised in that the gain factor for the respective measured values (x; y; z) of the sensor elements (11; 12) can be parameterised.
8. The offset printing machine as claimed in Claim 1, characterised in that the colour sensors (11; 12) are in each case configured as analog tristimulus sensors.
9. The offset printing machine as claimed in Claim 1, characterised in that the colour sensors (11; 12) are in each case configured as a colour sensor (11; 12) in each case exhibiting three discrete light-sensitive areas on its respective active surface.
10. The offset printing machine as claimed in Claim 1, characterised in that the colour sensors (11; 12) operate according to a normal spectral value function standardised in DIN 5033 or as per CIE 1931.
11. The offset printing machine as claimed in Claim 1, characterised in that each of the colour sensors (11; 12) has its own housing which at least acquires the light-sensitive active surface of the respective colour sensor (11; 12),
12. The offset printing machine as claimed in Claim 1, characterised in that in its arrangement the measurement bar (01; 02) can be tracked transversely to the direction of transport of the printing substrate (03).
13. The offset printing machine as claimed in Claim 12, characterised in that the measurement bar (01; 02) can be displaced about a travel path (s) in its arrangement transversely to the direction of transport of the print substrate (03).
14. The offset printing machine as claimed in Claim 13, characterised in that a control unit (39) dynamically controls or regulates the tracking of the measurement bars (01; 02) depending on the respective position deviation of a mark (37) of the print substrate (03).
15. The offset printing machine as claimed in Claim 1, characterised in that the output signal of any individual colour sensor (11; 12) can be tapped by the colour sensors (11; 12) arranged in a row or at the same time the respective output signal can be tapped by several of these colour sensors (11; 12).
16. The offset printing machine as claimed in Claim 1, characterised in that the at least one arrangement of sensor elements (11; 12) selected by means of the filter is assigned to one of the at least one significant placement of the printed image.
17. The offset printing machine as claimed in Claim 1, characterised in that the filter is generated from data prepared by a pre-printing stage (31).
18. The offset printing machine as claimed in Claim 1, characterised in that the filter is derived from printed images already present in the production run.
19. The offset printing machine as claimed in Claim 1, characterised in that the data-processing unit acquires the respective output signal of selected arrangements of sensor elements (11; 12) all arranged in the same row synchronously with a transport velocity of the print substrate (03).
20. The offset printing machine as claimed in Claim 1, characterised in that the data-processing unit is configured in the form of one or more freely programmable FPGA logic circuits.
21. The offset printing machine as claimed in Claim 1, characterised in that the print substrate (03) is configured as a print substrate web (03), whereby the print substrate web (03) in the offset printing machine has a transport velocity in the region of 15 m/s to 20 m/s.
22. The offset printing machine as claimed in Claim 21, characterised in that the pickup of the respective output signal of the selected arrangements of sensor elements (11; 12) arranged in a row is synchronised with the transport velocity of the print substrate web (03).
23. The offset printing machine as claimed in Claim 1, characterised in that at least one row of arrangements of sensor elements (11; 12) is arranged on both sides of the print substrate (03) in each case.
24. The offset printing machine as claimed in Claim 1, characterised in that the arrangements of sensor elements (11; 12) are separated off from each other by opaque walls.
25. The offset printing machine as claimed in Claim 1, characterised in that the measuring surface (28) extends both in the direction of transport of the print substrate (03) and also transversely thereto.
26. The offset printing machine as claimed in Claim 1, characterised in that the measuring field (29) is configured as circular or rectangular.
27. The offset printing machine as claimed in Claim 1, characterised in that an array of sensor elements (11; 12) acquiring the colour tone acquires a section of the printed image printed onto the print substrate (03).
28. The offset printing machine as claimed in Claim 1, characterised in that a face of each pixel printed onto the print substrate (03) is smaller than the measuring field (29) whereof the colour tone acquires one of the arrays of sensor elements (11; 12).
29. The offset printing machine as claimed in Claim 1, characterised in that the inline colour measuring system is part of a colour-regulation unit, whereby the colour-regulation unit regulates metering of the printing ink on at least one inking unit belonging to the offset printing machine.
30. The offset printing machine as claimed in Claim 1, characterised in that a production counter (41) detecting the number of printed images is provided, whereby a data memory (23; 27) of at least one arrangement of sensor elements (11; 12) in each case links and stores acquired measured values (x; y; z) to a counter status prepared by the production counter (41).
31. The offset printing machine as claimed in Claim 14, characterised in that the mark (37) connected firmly to the surface of the print substrate (03) is configured wedge-shaped with a tip directed in the direction of transport of the print substrate (03).
32. The offset printing machine as claimed in Claim 14, characterised in that the maximal expansion of the mark (37) directed transversely to the direction of transport of the print substrate (03) corresponds maximally to the travel path (s) to be described by the respective measurement bars (01; 02) for tracking.
33. The offset printing machine as claimed in Claim 14, characterised in that the mark (37) is configured as a right-angle triangle or as a stepped element.
34. The offset printing machine as claimed in Claim 1, characterised in that several discrete light sources (13) are provided.
35. The offset printing machine as claimed in Claim 34, characterised in that the light sources (13) are arranged in at least one row.
36. The offset printing machine as claimed in Claim 34, characterised in that each arrangement of sensor elements (11; 12) in each case forms a functionally separate assembly in each case together with the at least one light source (13) assigned thereto.
37. The offset printing machine as claimed in Claim 34, characterised in that the light sources (13) are in each case configured as a light-emitting diode (13) or as a laser diode (13).
38. The offset printing machine as claimed in Claim 35, characterised in that the at least one row of light sources (13) is arranged parallel to a row of arrays of sensor elements (11; 12).
39. The offset printing machine as claimed in Claim 1, characterised in that the arrangement of sensor elements (11; 12) is configured as a CMOS image sensor.
40. The offset printing machine as claimed in Claim 1, characterised in that it is configured as a web-fed printing press.

Images