EP0713447A1

EP0713447A1 - Device for the parallel image inspection and colour control of a printed product

Info

Publication number: EP0713447A1
Application number: EP94919655A
Authority: EP
Inventors: Harald Bucher; Gerhard Fischer; Wolfgang Geissler; Werner Huber; Helmut Kipphan; Bernd Kistler; Gerhard Loeffler; Clemens Rensch
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 1993-06-25
Filing date: 1994-06-22
Publication date: 1996-05-29
Anticipated expiration: 2014-06-22
Also published as: WO1995000335A1; US5724437A; EP0713447B1; JPH08511740A; AU7072494A; DE4321177A1; DE59403887D1

Abstract

The invention relates to a device for inspecting the image and measuring the colour of at least one printed product produced by a printing machine with at least one printing group. The purpose of the present invention is to propose a device permitting the quality and colour of printed products to be assessed. To do this, the device consists of at least one imaging device (12) providing the image data of the printed product and a computer device (17), in which the computer device (17) detects all the image data of the printed product for image inspection and finds a measurement colour assessment from the image data of at least one measuring point of printed product.

Description

Device for parallel image inspection and color control on a printed product

description

The invention relates to a device for image inspection and color measurement on at least one printed product _/ which was created in a printing press with at least one printing unit.

From EP 0 324 718 A1 a method and a device for color control of a printing press have become known. On the basis of the spectral measured values of a color control actual series, the required changes in layer thickness in the individual color zones of the individual printing units are calculated in the event of a deviation of an actual color location from a target color location using a special calculation method (linear model). As a colorimetric control a regulation regarding the color impression that the human eye is receiving from a printed product _/ tracked _/ a high print quality can be achieved. The _/ colorimetric control method for a printing press described in EP 0324718 A1 is to be regarded as a ADVANTAGES lhafte embodiment of the colorimetric control and as an integral part of the present patent application.

A device for carrying out a comprehensive quality control on printed sheets is described in EP 0 410 253 A2. The image data of a printed product are _/ captured by a video camera _/ which is arranged above a matching table. The data are stored in a memory for digital image data. Parallel to the video camera is a light source both for displaying data and provided as a guiding device for the measuring devices. Between the video camera and light source are one or more systems for image evaluation _/ particular for pattern recognition _/ provided _/ which use the data of the memory for the image data. Color measuring devices and register measuring devices are particularly suitable as measuring devices.

The present invention is based on the object _{/ of} creating a device _/ which at the same time permits quality and color evaluation of printed products.

The object is solved _/ that the device consists of at least one image capture device _/ the image data <: = lagekorre profiled measurement data) delivered by the printed product _/ and consists of a computing device _/ said computing device on the one hand determined ldinspektion all the image data of the printed product for the purpose of a Bi and on the other hand, from the Image data of at least one measuring point (pixel) of the printed product determines a measured variable for the color evaluation. The image data for image inspection and color evaluation can originate from one as well as from different printed products.

For the first time, a device is proposed _/ which simultaneously fulfills two requirements determining high print quality. On the one hand, an evaluation is carried out with regard to the print quality on the basis of the entire image data record of the printed product (printed product: = sheet and / or printed image). An actual setpoint comparison is used for this _/ z. B. slugs, inadequate moisture management _/ duplication _/ register ehler _/ as well as geometric positional errors of the printed image on the sheet and defects in the sheet, but also to detect missing sheets. Furthermore, based on the image data of certain areas _/ at least one pixel of the printed product _/ measured variables for a color evaluation. According to advantageous further developments of the device according to the invention, it is provided _/ these measured values either on a display means _/ z. B. a monitor _/ to vi sua li si eren and / or derive a control / Rege I size for the color control in the individual printing units from the measured values.

According to advantageous further developments of the device according to the invention it is provided _/ that the image acquisition device is used both inline and offline _/ and in the latter case it is arranged above a storage device for printed products. Such a storage device is described, for example, in EP 0 410 253 A2 ^~ already cited above.

If the device according to the invention is used within the printing press _/ a rotation angle transmitter is also provided and at one

A web-fed rotary printing press can additionally have a sensor for detecting the start of the web and / or image. Of a trigger electronics, the image capturing device (the image capture devices are) driven so _/ that it provides image data from the entire printed product (provide) _/ the geometrical resolution of the Bi lddaten is independent of the printing speed. Advantageously, it is the

Image capture device around at least one camera _/ which scans the printed product line by line.

The data rate is determined in particular when the device according to the invention is used inline by the resolution _/ ie the number of pixels per scanned line _/ and the printing speed. About faulty sheets as a result of slugs _/ as a result of inadequate color management or as a result of register errors as well as inadequate ones color match instantly with a fine-Druckbi Id _/ so be seen in real time _/ _/ the computing device must meet relevant requirements. It must also be ensured _/ that both the noise and the crosstalk are largely eliminated _/ so that a high-quality signal evaluation is possible.

Particularly high demands are placed on measuring accuracy with an inline color measurement in real time. Disturbances within the measurement range must be limited _/ that their influence is on the color values within vorgebener color tolerances here ready. Since, in particular, angle errors _/ but also position errors of the printed product _/ when observing the selected area on the printed sheet lead to color measurement errors _/ care must be taken with regard to both the optics and the lighting _/ that such angle errors do not lead to an uncontrollable falsification of the color measurement values. Special configurations _/ which largely eliminate angle errors or color errors _/ are described in further configurations of the device according to the invention at a later point.

In particular, the Bi is lderfassungseinrichtung and the inventive device _/ that identical components for off-line or i ne nli tasks are used designed so on. This gives system-consistent data _/ for example, the data of an offline measuring device can be used as target data for the inline measurement. There are also cuts _/ around non-native data _/ e.g. B. spectral data _/ to be able to take over.

According to an advantageous development of the device according to the invention is provided _/ a that

Image capture device consists of one or more measuring modules and at least one correspondingly assigned receiving device. As previously described _/ For a color measurement, or the subsequent display and / or control, data with high reproducibility must be provided. As already described _/ the computing device must meet certain requirements for this. On the other hand, however, it must also be ensured with regard to the optics and the image data preparation _/ that the measured values are not falsified and / or unusable due to uncontrollable influences. The modular structure of the measuring bar takes these requirements into account very well.

Due to the modular structure, a largely homogeneous irradiation of the defined area on the printed product is achieved. In addition, the direct proximity between the printed product to be scanned and the external radiation measurement module _/ which directly influences the measurement signals _/ largely shields it. Especially when used inline, the proximity of the object also has a positive effect in the direction that vibrations of the printing machine interfere little with the geometry of the defined image area and thus cause no color measurement errors _/ which are outside of the specified _/ permissible tolerances. Color tolerance always means the color change _/ which the human eye perceives as a tolerable color deviation.

The modular structure of the measuring bar also has a positive effect with regard to the processing speed of the image data. The parallel data acquisition is to be seen as an advantageous preliminary stage of a subsequent parallel data processing.

As already described _/ exists

Image acquisition device comprising one or more measuring modules and one or more _/ the receiving device (s) generating the image data. With regard to the structural design of the image acquisition device, two variants can be mentioned. Either these are the measuring module (s) and the receiving device (s) generating the image data is spatially separated from one another and connected to one another via image conductors _/ or the measuring modules and the receiving device (s) generating the image data are integrated in the measuring bar. While the latter alternative is quite advantageous for an offline measurement _/ shows the first variant of advantages in a nli i ne-Ei APPROACH, that is, upon detection of the image data within the printing press. - Due to the spatial separation of the opto-mechanical _/ from the electrical or electronic elements of the receiving devices _/ in particular the highly sensitive CCD line arrays are to be mentioned _/ the receiving devices can be placed outside the printing presses. With this configuration, mechanical or electromagnetic vibrations _/ which have a negative effect on the recording and further processing of the measured values, in particular at the measuring location _{, are} largely eliminated. Another advantage of the separation of the measuring modules of the receiving means lies in _/ that the measuring modules - and thus also the measuring beam - have a relatively small dimensions. The free accessibility of the cylinders of the individual printing units of the printing press is thereby kept within an acceptable framework. The measuring bar is therefore also suitable for several installation locations.

Another very advantageous embodiment of the measuring bar provides ₇ that the measuring bar is constructed modularly from individual measuring modules _/ deliver the image data from the defined image area. Due to the modular structure of the measuring bar, it can be easily adapted to any format of the printed product - ie to different machine widths.

According to a further development of the ADVANTAGES lhaften erf ndungsgemäßen device is provided _/ that each measurement module are assigned at least one illuminating device and a front lens _/ the defined image area on at least one Show line-shaped image conductors (single image conductor) _/ with several image conductors per measuring module (multiple image conductors), a corresponding number of line-shaped image conductors are layered on top of one another. Each image conductor itself is composed of a plurality of adjacent and possibly superimposed optical fibers together _/ ldleiters are arranged at the two ends of the Bi so _/ that a geometrically undisturbed Bi is ensured ldübertragung. Each image guide itself can in turn be of single-layer or multi-layer design.

According to an advantageous development of the inventive device _/ the ldseite on the Bi zel ldeten lenförmig Trained and possibly parallel stacked zei lenförmigen Bi are ldleiter layered on the receiving side at a defined distance above the other and lden as a regular layer structure bi. Particularly advantageous is the design _/ that the image conductors are joined together on the reception side to form an optical connector. This makes it possible without any problems _/ to vary the number of image conductors in the connector as desired _/ and to replace the image conductors - for whatever reason.

In the case of multilayer "single-image conductors" there are two possibilities _/ to arrange the individual image conductors in the connector. So z. B. in a colorimetric measurement, the X, Y, Z and NIR channel (J.ahes J ifra-J ot, four-layer "single image conductor") corresponding image conductor of each measuring module on the receiving side layered one above the other in blocks; The outputs of the optical connector are then mapped onto the CCD line arrays using an optical system that essentially consists of a beam splitter and color filters (: = color filter + NIR filter). The second option saves you Beam splitter on: the line-shaped image conductors layered one above the other on the image side are joined to form a connector on the reception side _/ with exactly one image conductor from each measuring module being contained in a block of the connector. This connector therefore contains four blocks of image conductors _/ which correspond to the X _/ Y _/ Z and NIR channels. At the output of the connector there is already a distribution of the radiation according to the individual color channels. Therefore, the beam splitter can be omitted in this version, an optical system _/ the image area defined which consists essentially of color filters _/ is mapped to the correspondingly associated receiving device. It should be noted in this second version ^" that the saving of the beam splitter leads to losses in terms of the spatial resolution. However, this disadvantage can be compensated for by software _/ by transforming the spatially separated measuring locations of the individual color channels into the correct geometry.

According to a ADVANTAGES lhaften embodiment of the receiving means is provided _/ that it consists of a number of defined distance parallel to each other arranged _/ consists of photosensitive elements _/ the number of which Ortsauf solution of the image acquisition device determined. Advantageously, the receiving device is a CCD line array. With the CCD lines or the CCD line arrays, conventional control electronics are coupled _/ which is used for clock control of the CCD lines or the CCD line arrays, for signal amplification and sampling of the signals and for A / D conversion. The image data of the entire printed product are then present at the output of the receiving device.

The CCD elements must be precisely adjusted with regard to the ends of the conductors, since otherwise image disturbances (convergence errors _/ "alignment") will result. To minimize the adjustment effort _/ is according to an advantageous Further development of the device according to the invention proposes the following: a field diaphragm with a plurality of funnel-shaped openings is connected downstream of the output of the image conductors. The spa-shaped openings define the area of the assigned image guide to be mapped onto the respective CCD lines. In particular, there is provided _/ that the cross section of the image conductor is larger and that the output of each image conductor of the optical axis of the first lens on the receiving side of the image guide is adjustable as a field stop with respect to a holder. The number of adjustment processes corresponds to the number of image guides _/ is therefore relatively small. The image of an image conductor end on the assigned CCD line is advantageously smaller in the printing direction than the CCD line height itself _/ which enables larger adjustment tolerances.

The receiving unit to the optical tolerances to keep especially for color control also very low _/ is optically in a preferred embodiment Trained Idet as follows: the Bi ldleiterenden be displayed by means of two lenses on the CCD line. The two mutually assigned lenses are each in the focal point of the other lens _/ so that the space is ideally irradiated in parallel (4-f arrangement).

According to a preferred embodiment, the beam splitter is also accommodated in this intermediate space _/ so that the imaging takes place by means of a first objective and four second objectives.

With regard to color measurement, this arrangement has the advantage _/ that only one optical filter per color channel is required for all optical modules. Here a comparable filter behavior is guaranteed for all pixels _/ since the individual filters are penetrated vertically by the radiation. In particular, the above-mentioned 4-f arrangement of the lenses makes it possible to use parti a ifi iters. According to a further development of the device according to the invention, it is provided that the color filters consist of several different filter parts (Partia Ifi Iter) which can be shifted relative to the diaphragm. This serves to fine-tune the transmission curve of the corresponding color channel Is.

An embodiment of the device according to the invention provides that the field diaphragm has a darkened area between the position of the image information and the position of a white reference of the lighting devices of the measuring modules. The coupling of the white reference serves to standardize the individual lighting devices with one another. The above-described division of the coupling area from the actual image transmission area clearly separates the two areas.

In order to achieve a secure adaptation of the geometries of the image conductor ends stacked in the connector to the geometry of the CCD lines, an opto-mechanical coupling element is proposed according to an advantageous embodiment of the device according to the invention. This coupling element consists of a front block and a rear side block, which are connected to one another via light guides. While the front block is adapted to the geometry of the image guide stack, the back block has the geometry of the CCD lines. In terms of production technology, this coupling element is easier to handle than the relatively long image conductors which connect the measuring bar to the receiving unit. Furthermore, due to the optical imaging laws, the geometry of the CCD lines is linked to the geometry of the image guide stack via the imaging scale of the optical system. Since in in general, it is not certain that the geometrical dimensions of the image guide stack, optical system and receiving devices match each other -. For example, for technological or economic reasons, there are upper or lower limits for the dimensioning of these components or it may make economic sense not to choose the connector in the size that matches the illustration, but larger - this configuration proves to be extremely useful anyway.

The following advantageous further developments of the device according to the invention relate to the illumination of the defined image area.

The lighting can either be direct or indirect. In this context, indirect lighting means that radiation from a light source is directed via a cross-sectional converter and a mirror, for example a cylindrical mirror, into the selected image area. This indirect lighting is particularly suitable for the integrated training of the measuring module, where the temperature-sensitive receiving devices and electronics are integrated in the individual measuring modules.

With direct lighting, the radiation from the lighting device falls more or less directly into the selected image area. Since it is of great importance for a reliable color measurement that the radiation shows a homogeneous distribution in the selected image area - in particular, this means that no lateral fluctuations may occur - it is provided according to a further development that the radiation passes through an elongated elliptical mirror in the selected area. Because of the favorable spectral re ﬂ ection properties, the elliptical mirror is optionally coated with chrome, or it is made of aluminum with a silicon oxide coating. For standardization, regulation and calibration of the

It is provided among each other that the radiation from each individual lighting device is coupled to a respective light guide, the output of which is connected directly to the corresponding image guide and is measured in each of the color channels. This makes it possible for measurement values to be provided for each lighting device, which are then standardized to the corresponding values of a standard light source. In particular, a lamp control is provided which adjusts the current for the lighting devices in such a way that their radiation intensity is compared with one another.

In addition to the lateral homogeneous illumination of the defined image area, it must also be ensured that the radiation has a spectral composition that is constant over time. In addition, the radiation intensity should be somewhat the same in the entire relevant wavelength range, which lies between approx. 400 nm and the "} aah ^ nfrraot" (NIR). Furthermore, for a reliable color control, the dependence of the spectral composition of the measuring radiation on the measurement location on the printed product and on the type of printing material must lie within permissible color tolerances. Only if this is ensured can the same spectral correction function, i.e. the same color filter or optical filter (NIR), be used for any measurement location and any type of substrate.

Precision halogen lamps, which are controlled by separate, programmable precision current sources, are advantageously used as lighting devices. By coupling the radiation of the lighting devices (white value) onto the individual image conductors as described above, the light of the lighting devices is measured in each of the spectral color channels. The measured values are standardized with the corresponding measured values of a standard. These show a correlation to the temperature T. If the standardized measured values are plotted against the corresponding color channels, the relative intensities change depending on the temperature. On the basis of these relative intensities, the current of the assigned lighting devices is now controlled via an inverting amplifier. This type of lamp control based on the color temperature of the

Lighting devices ensure that each of the lighting devices emits radiation of the same intensity in the entire relevant spectral range.

For exact adjustment of the light guide with respect to the respective lighting device, it is provided that the light guide is arranged in a bore, the axis of which is directed towards the lighting device. In particular, the light guide is arranged adjustable within this bore.

According to an advantageous further development of the device according to the invention, which also takes into account the high requirements for the resolution of the color measurement values, it is provided that the value of the white value of each lighting device currently measured and averaged in each color channel is used to standardize the color measurement values and that the current value thereof averaged dark current of the CCD lines is subtracted.

The image data are recorded on the finished printed product. Therefore, the image capturing device in a sheet-fed printing press is preferably assigned to the printing cylinder of the last printing unit or additionally to the printing cylinder in front of the reversing drum if the sheet-fed printing press works in the perfecting mode. In a web-fed rotary printing press, there are two image capturing devices for scanning the printed web provided. In the case of a web-fed rotary printing press, the image capturing devices are advantageously assigned to the cooling rollers or the deflection rollers thereafter. These measures ensure that the print image is captured on the dried printed product. Since dampening solution increases the specularly reflected radiation component at the measuring location, polarization filters which have to be introduced into the beam path to suppress the specularly reflected radiation can thus be omitted in this arrangement.

Measures have been previously described which minimize a dependency of the color measurement values on the measurement location in such a way that the fluctuations in the color measurement values caused as a result of this dependency lie within permissible color tolerances. The color values are not only dependent on lateral and lateral ^'changes, they also depend on the object distance. It must therefore be ensured that the printed product is at a well-defined distance from the lighting device or in particular from the front optics. The reproducibility of the measurement location on the printed product is of course also of great importance with regard to the correlation between encoder signals and print image of the printed product. By blowing an air flow against the direction of travel on the printing sheet, it is fixed on the printing cylinder. According to an advantageous embodiment of the blowing air device, it is provided that the pressure of the blowing air is chosen in accordance with the nature of the printed product, for example in accordance with the thickness or the rigidity of the printed product. By entering the thickness or stiffness of the printed product on an input device, the blown air is automatically regulated via a control. For example, a high blowing air pressure is provided for cardboard, while a lower blowing pressure is provided for a low thickness or stiffness of the printed product is chosen because with thin, flexible papers, high pressures could lead to the formation of waves, which would run counter to the actual meaning and purpose of the air-blown position of the printed product.

A fixation of the printed product is also possible by sucking the printed product onto the cylinder or by electrostatically charging the printed product and / or the cylinder. In particular, it is provided that the blowing nozzles are controlled on the basis of the image data. So it is z. B. also possible to apply the blowing device f.ormatvari abe l - to the side and in the direction of pressure - with blowing air. Advantageously, it is provided that the blowing air supply lines are constructed in such a way that the blowing air flow is simultaneously used to cool the lighting devices.

Photometric calibration of the image capture devices is required for an absolute color measurement; barium sulfate (absolute white) is usually used for standardization in color measurements. Since barium sulfate is only available in tablet form as a pressed powder, it is not very suitable for online use. A plastic tile (oak white) can be used as a replacement, the optical properties of which are known relative to barium sulfate.

The calibration white is arranged, for example, on the surface or a region of the surface of the cylinder, or it is located on a separate carrier in the channel of the respective cylinder, with respect to which the image capturing device is arranged. The image capturing devices are usually calibrated during printing breaks. However, if the calibration white is arranged in the channel of the cylinder, the calibration in sheet-fed printing machines can also be carried out during the ongoing printing process. In addition to the color calibration, the constancy of various operating parameters must also be checked during operation. For this purpose, (self-illuminating) "calibration surfaces" are swiveled into the beam path at a suitable point. For example, this measure is used to check the time dependencies. If necessary, a message is given to the operator when a new color calibration has to be carried out.

A further solution provides for the following: an additionally coupled bi-idle layer at the end of the image guide "looks" at the "calibration surface".

A particularly advantageous embodiment with regard to the calibration of the image acquisition devices can be implemented as follows:

A protective housing is assigned to the measuring bar. Both, measuring bar and protective housing, have a common axis. The measuring bar is pivotally mounted about the axis and can be locked in two positions, a measuring position and a parking position. In the measuring position, the printed product is scanned on the cylinder. The radiation of the illuminating device advantageously falls onto the surface of the printed product at an angle of 45 °. During printing breaks, the measuring bar is swiveled into the park position and is now inside the protective housing. This protects the sensitive optics from splash water (the rubber blanket is usually washed during printing breaks). According to an advantageous development of the measuring bar according to the invention, however, provision is also made for the calibration white to be arranged in the protective housing. In particular, the protective housing is dimensioned such that the optical intersection of the respective lighting device and the front optics in the parking position focus on the surface of the standard spotlight. The standard radiator is advantageously arranged over the entire width of the protective housing. The optical system, which images the outputs of the image conductors or the intermediate image on the respective receiving devices, can be designed in a variety of ways, in particular in the case of integral embodiments of the device according to the invention. So it is possible that the optical system is a beam splitter, the individual outputs of which are assigned optical filters with imaging optics. It has proven to be particularly advantageous to illuminate the defined image area at an angle of 45 ° and to arrange the front optics perpendicular to the surface of the printed product. However, the reverse arrangement of the lighting device and the front optics is also possible.

In a particularly advantageous development of the device according to the invention it is provided that a part ia Ifi Iter is arranged in the common focus of two lenses of the optical system.

Another very advantageous embodiment of the device according to the invention, which both in the separate and in the integrated version of the

Image acquisition device can be used, provides that the optical system is a prism or a grating. Both are known to cause spectral decomposition of the measuring radiation. The measuring radiation of each image point (pixel) of the defined area of the printed product is spectrally broken down, the spectrum is mapped onto parallel arranged CCD elements (surface array). Since spectral measurement values are provided from each individual pixel of the defined image area, a spectral resolution is additionally achieved. The spectral, spatially resolved measuring radiation is received by a CCD surface array and subsequently converted into image data. It proves particularly advantageous in this embodiment that the computing device subsequently processes the spectral measured values in this way can weight that any desired Fi filter functions are simulated by software. The color filters and thus the high demands that are usually placed on the filter functions of these color filters with regard to reliable color measurement are eliminated.

According to the invention, the image data of the entire printed product are used both for image inspection and for color control. In particular, it is provided that the computing device divides the shading-corrected and logarithmic image data into data for image inspection and into data for color control. For image inspection, differential image data are used, which are linked to pixel-stored ^" values ^{" from} a separate memory and processed further as weighted differential image data. This memory contains, on the one hand, information as to whether the image point in question is also used for color measurement in addition to image inspection. on the other hand, there is, for example, coded, the weight with which a difference between a target image value and the corresponding actual image value is to be applied. Advantageously, the computing device standardizes and compares the image data for image inspection with respect to corresponding target data. Furthermore, there is a memory The computing device monitors both the current and the accumulated differential image data with corresponding thresholds. The color requirement of a zone can be determined on the basis of the accumulated differential image memory and a computer , because the image data is completely available. For example, this information can be used to determine when the lateral trituration is to be used.

Errors within the printed image are recognized on the basis of the difference image. Such errors are, for example Hog, toning areas behind Vol Itonf Lachen due to lack of dampening solution guidance or register errors.

According to the invention, the image data are also used for color control according to e.g. B. colorimetric sizes used. For this purpose, the computing device selects at least one coherent area z from the image data. B. per color zone. In the minimum case, the contiguous area is a picture element (pixel). Furthermore, the computing device determines the actual color location of this area, compares it with the corresponding predetermined target color location and, if the color distance is outside the tolerance, causes a compensating adjustment of the corresponding ink control elements of the individual printing units. Color control according to colorimetric parameters has already become known from the prior art. In particular, reference is made to EP 0 324 718 A1, which is to be regarded as an integral part of the present patent application.

Alternatively, according to a Ausbi of the inventive device provided ldung _/ that the operator through an interactive interface provides a bi ldbereiche selects for color control. In particular, image areas and setpoints relevant for color control can also be provided by an offline measuring device of the computing device. For this purpose, defined interfaces are provided _/ which allow additional devices to be included in the control process.

The related areas are selected based on certain criteria. So we take special care _/ that a maximum of four colors occur in the selected area in a homogeneous distribution as possible. In particular, fields _/ z. B. gray fields _/ used _/ which are characterized _/ that color errors appear quickly and sensitively. Of course, the connected areas can also be measuring fields of a color control actual row.

On the basis of the complete image data set of the printed product, an area that is relevant and meaningful for the color control is selected automatically or interactively with the operator. A graded classification of each pixel (parameter memory) checks, among other things, its suitability for color measurement during printing. In particular, image areas with geometric or locally limited errors are automatically sorted out and are not used for the subsequent color measurement / color display / color control. By capturing all the image data of the printed product, the selection of certain measuring points can be carried out without major problems using a proof sheet or ok sheet. A transfer of the data of an offline measuring device with regard to the size and the position of the selected areas to the computing device _/ can be carried out without great expenditure of time.

Register errors affect the color impression. Color control is therefore only sensible _/ when the print products are in register. For this purpose, addition _/ if the resolution of the Bi lderfassungseinrichtung is insufficient _/ domestic or offline at least one register sensor _/ z. B. a register camera _/ provided the z. B. consists of a CCD surface array. With this register camera, register deviations between the individual printing units can be recognized and corrected. According to an advantageous embodiment of the register measuring device, it is provided that it is arranged on a crossmember with respect to a corresponding printing cylinder in the printing press. In the case of a web printing press there is at least one Register camera for scanning the printed product on both sides is provided, which carries out a register measurement on the printed printed product. In particular, this register camera is also assigned to the printing cylinder of the last printing unit (sheet printing machine) or to the cooling rollers or deflection rollers (web printing machine).

The invention is explained in more detail with reference to the following figures.

It shows:

1 shows a longitudinal section through a printing press with the device according to the invention,

2 shows a schematic representation of the system components of an embodiment of the device according to the invention in a sheet-fed printing press,

3 shows a schematic representation of the system components of an embodiment of the device according to the invention in a web printing press,

4 shows a schematic overview of the system components of an embodiment of the device according to the invention in a printing press,

5 shows a basic structure of an embodiment of the device according to the invention for obtaining image inspection and color data,

6 shows a cross section through the measuring bar according to an embodiment of the device according to the invention _/

7a) is a block diagram for controlling the lighting devices _/ 7b) a cross section through an image guide with white reference coupling,

Fig. 8 shows a cross section through the measuring bar according to an embodiment of the device according to the invention

a) in measuring position,

b) in parking position,

9 shows a schematic representation of an embodiment of the device according to the invention with multilayer single-conductor conductors,

10 shows schematic representations of an embodiment of the device according to the invention with a quad image guide,

a) a side view of the quadruple image guide,

b) a top view of the quadruple image conductor according to marking A in FIG. 10a),

c) an image of a defined image area on the receiving device according to the embodiment from FIG. 10a) or from FIG. 10b),

11 arrangement of a coupling member between the image conductor ends and the receiving device,

12 shows a longitudinal section through the coupling member between the image conductor ends and the receiving device according to FIG. 11, 13a shows a longitudinal section through an embodiment of a beam divider which is used in the device according to the invention,

13b shows a longitudinal section through another

Embodiment of a beam splitter that is used in the device according to the invention,

14 is a sketch of the measurement geometry and the beam path in a measurement module,

15 shows a first embodiment of a measuring module with integrated receiving device;

16 shows a further embodiment of a measuring module with integrated receiving device;

Fig. 17 shows a third embodiment of a measuring module with integrated receiving device.

18 shows a fourth embodiment of a measuring module with an integrated receiving device

and

Fig. 19 shows an embodiment of the device according to the invention.

1 shows a longitudinal section through a partial area of an offset printing press 1, the arrangement of the image capturing devices 12 with respect to individual cylinders 5 of the printing press 1 being shown in particular. The printing press 1 is composed in a known manner from a plurality of printing units 2, an feeder (not shown separately in FIG. 1) and a delivery arm 11. Each of the printing units 2 shows the usual ^•

Cylinder configuration: plate cylinder 3, rubber blanket cylinder 4 and printing cylinder 5. The printing plate clamped on the plate cylinder 3 is moistened via the dampening unit 6 and inked with the corresponding ink via the inking unit 7.

The sheet guiding between the individual printing units takes place via the transfer cylinder 8 and the half-speed transfer drum 9, or in the case of perfecting, the reversing drum 10. In the individual printing units 2, the sheet 32 is successively between the rubber blanket cylinder 4 and the printing cylinder 5 printed with the individual color separations.

In straight printing, the image acquisition device 12 is assigned to the printing cylinder 5 of the last printing unit 2. In the case of a printing machine working in the perfecting and reverse printing, a further image capturing device 12 is assigned to the printing cylinder 5 before the turn.

But it is also quite possible that

Attach image capturing device 12 in front of the delivery arm 11 with respect to the turning drum 10 or with respect to the last transfer drum 9. It is also possible to scan the image of the printed product 32 in the area of the delivery 11. Of course, it must also be ensured here that the printed product 32 assumes a clearly defined position during the image acquisition. In particular, a stabilizing element 67 is provided in the area of the sheet guide in the boom 11. The image capturing device 12 is arranged above this stabilizing element 67 and captures the image data of the printed sheet 32.

2 shows a schematic representation of the system components of an embodiment of the device according to the invention in a sheet-fed printing press. The Printing unit 2 again shows the usual

Offset cylinder configuration: plate cylinder 3,

Rubber cylinder 4 and pressure cylinder 5. On the shaft of the

Printing cylinder 5, a rotary encoder 13 is installed, the

Information about the respective angular position of the

Printing machine 1 forwards to the computing device 17.

The measuring bar 14 is fastened above the printing cylinder 5. During the ongoing printing process, the individual measuring modules 27 of the measuring bar 14 record the image data of the finished printed sheet 32 line by line.

The measuring modules 27 of the measuring bar 14 are spatially separated from the receiving devices 16 - advantageously, these are, inter alia, zei-shaped CCD elements 38. The connection is made via image conductor 15. This spatial separation of the optical component of the measuring bar 14 and the receiving devices 16 and the electronic processing of the image data means that the thermal load on these elements that occurs at the measuring location through the lighting devices 28 of the measuring bar 14 is automatically switched off. In addition, it is possible with this division without problems to decouple mechanical vibrations of the printing press 1 as well as electromagnetic interference radiation from the receiving devices 16. Another advantage l, which inevitably arises due to this separate construction, but is of crucial importance for the arrangement of the image capturing device 12 in the printing press 1, is the relatively small size of each individual measuring module 27 of the measuring bar 14. 2 shown embodiment only a few optical components are housed in the individual measuring modules 27 of the measuring bar 14, the measuring bar 14 can easily be dimensioned so that its placement within the printing press 1 is relatively easy borrowed. At the output of the receiving units 16, the reflectance values of the image points of the entire printed sheet 32 are available as digital image data. These data are forwarded to the computing device 17. In the computing device 7, the digitally available image data of the entire printed product 32 are divided - specifically into data that are used for color measurement and into data that serve to inspect the printed image. The computing device 17 may also receive information from the register sensor 18 about the register stability of the printed product 32. Since register errors inevitably lead to color errors, it must first be ensured with a color measurement / display / control that the register is correct. Any necessary corrections to the register are carried out by the machine controller 21. The measured values for the register setting are - as already mentioned - e.g. B. provided by the register sensor 18, which is arranged in the printing press 1, or alternatively they are supplied by a register sensor 22, which carries out a corresponding measurement offline.

While all image data of the printed product 32 are used for image inspection, only certain representative areas, e.g. B. selected per color zone 44. This selection is computer-controlled according to predefined criteria; alternatively, it is provided that the printing personnel select measurement areas via the operating device 19 which are of crucial importance for the image impression. Input means 25 are provided for selecting this area; For example, these input means 25 are a keyboard, a mouse or a trackball, via which the coordinates of the relevant image areas are entered, which are subsequently forwarded to the computing device 17. Furthermore, there is a display means 26 provided _/ on which the currently captured image of the printed product 32 is displayed.

The operating device 19 is connected both to the offline measuring device 20 and to the machine control 21. This makes it possible _/ on the basis of an ok image to select relevant image areas within the printed product 32 and to determine target values for them _/ which are subsequently used for the color control of the printed product 32.

Recognizes the computer 17 intolerable chromatic aberrations of the printed product 32 or on the image inspection defective sheet _/ do not meet the usual high pressure Standard _/ found _/ as a corresponding signal is z. B. spent on a waste paper gate _/ ie, the faulty sheets are sorted out. Such so-called maku switches are well known from the prior art. The waste switch described in DE 30 29 154 C2 may be mentioned as an exemplary embodiment.

Color errors are automatically displayed and / or corrected via the machine control 21. Other errors which have a significant influence on the print quality, for example geometrically or locally limited errors, such as slugging or toning as a result of inadequate fountain solution guidance, are identified by comparing the target data of the print product 32 with the corresponding actual data of the print product 32 just created. When slugs appear, for example, a slug catcher is automatically activated. The dampening solution flow is also automatically adjusted when toning occurs. Of course, these corrective interventions or corrections can also be carried out manually. Fig. 3 shows a schematic representation of the system components of the device according to the invention in an offset roller printing machine. Here, too, the printing unit 2 shows the usual cylinder configuration, consisting of plate cylinder 3 and rubber cloth cylinder 4, which are each arranged on both sides of the web 32 to be printed. A rotary encoder 13 is arranged on the shaft of one of the rubber cloth cylinders 4.

After the last printing unit 2, the web passes through a dryer device (not shown separately in FIG. 3) and is then cooled via a cooling roller system consisting of a plurality of cooling rollers 24. With respect to these cooling rollers 24, a measuring bar 14 with measuring modules 27 is arranged, which scan the web 32 printed on both sides.

The sensors 23 are used to detect the beginning of the image on the web 32. The signals from the image start detection sensors 23 and

Angle of rotation encoder 13, which is arranged on the shaft of a cylinder 4 of the printing press 1, or the trigger electronics 60 are forwarded to the computing device 17. In order to be able to exclude color errors as a result of register errors from the outset, register sensors 18 are arranged on both sides of the web. The measurement data of the register sensors 18 are also fed to the computing device 17, which causes a possibly necessary correction of the register in the individual printing units 2 via the machine control 21.

The two image capturing devices 12, which each deliver image data from one side of the printed web 32, are composed of two parts: the measuring bar 14 with the measuring modules 27 and the receiving devices 16. Both Parts arranged separately from one another are connected to one another via image conductors 15.

Image data in digital form are present at the output of the receiving devices 16. These data are divided in the computing device 17 into data for image inspection and into data for color control. While for image inspection all current data of the printed product 32 are compared via a sol actual value comparison with corresponding target data of an ok Image are compared, only certain areas, e.g. B. per color zone 44 selected. The measurement points for the color control are selected according to certain criteria. So it is ensured that in the selected area z. B. four colors are present in as homogeneous a distribution as possible. In particular, critical image-determining areas are used for color control, since they have a decisive influence on the image impression.

The color data is either selected automatically on the basis of the data record of the print image, or the selection is made “manually” by the operating personnel. For this purpose, the computing device 17 is connected to an operating device 19 _/ which has, among other things, input means 25 and display means 26. As already described in connection with FIG. 2, it is also provided in accordance with this embodiment that the selection of the two Levant locations can be made on the basis of the data from the offline measuring device 20. It is also possible for incorrect register lungs of the register to be detected via a register sensor 22 arranged offline. The computing device 17 then recognizes both color errors and other errors in the printed product and initiates appropriate corrections via the machine controller 21.

The individual system components of the image capture device 12 according to the invention are shown in FIG. 4, The essential components are summarized in blocks A, B, C, D. In block A the arrangement of the measuring bar 14 with respect to the surface of the printing cylinder 5 and the individual components contained in the measuring bar 14 are shown. Block B contains the receiving devices 16 and the conversions of the analog remission values into digital image data. By using image conductors 15 between the blocks A and B, it is possible to spatially separate the measuring bar 14 from the receiving devices 16.

The image data are forwarded to the computing device 17, which is housed in block C. This arithmetic unit 17 itself consists of several computers which, on the one hand, divide the image data into data for image inspection and, on the other hand, into data for color control. The results of the calculations, which are carried out in block C, are forwarded to an operating device ..19 or to a machine control 21, which is accommodated in block D of FIG. 4. This operating device 19 consists, among other things, of input means 25 and display means 26, both the input means 25 and the display means 26 likewise being computer-controlled.

The individual blocks A, B, C, D from FIG. 4 are explained in more detail below:

In block A, the measuring bar 14 is shown as an essential component of the image capturing device 12. The measuring bar 14 consists of individual measuring modules 27 which scan the printed product 32 line by line on the printing cylinder 5. An illuminating device 28 is arranged in each measuring module 27, which illuminates the printed product 32 directly or indirectly. The light remitted from the surface of the printed product 32 is imaged on at least one image guide 15 via a front objective 30. For surveillance of the lighting devices 28, in particular for regulating the lighting devices 28, a white reference coupling 29 is provided per measuring module 27, which couples the radiation from the lighting device 28 directly into a specific area of the image conductor 15.

In order to ensure that all the lighting devices 28 in the individual measuring heads 27 of the measuring bar 14 each transmit the same spectral characteristic to the printed product 32, a separate lamp control 61 is provided. This lamp control 61 is either integrated directly in block A, but can also be assigned to the computing device 17 just like the trigger electronics 60 and thus be spatially separated from the optics in the measuring bar 1 ^″ 4. The trigger electronics 60 receives the signals of the

Angle of rotation encoder 13 and - in the case of a web printing press additionally a signal that the respective

Marks the beginning of the track section. The trigger electronics 60 assigns the image data of the receiving devices 16 or the CCD line arrays 38 to their corresponding ones. Position coordinates on the printed product 32 too.

In the computing device 17, the image data supplied by block B is divided into data for image inspection and data for color measurement. In the case of two-sided printing, there are two data records. As soon as errors are recognized in the printed products 32, the computing device 17 can e.g. B. a signal for the waste paper switch is issued, ie defective sheets or inferior folding products are automatically sorted out. Furthermore, the computing device 17 is connected to the operating device 19. This operating device 19 is assigned input means 25 _/ which allow the operating personnel to select certain image areas for the color control. Furthermore, output means 26 are provided _/ the allow, among other things, an optical reproduction of the finished printed product 32 in real time.

Description of individual system components of the device according to the invention

1. The measuring bar

The measuring bar 14 as sketched in Fig. 9 _/ has a modular structure made up of individual measuring modules 27th The individual measuring modules 27 each scan line-by-line from a defined image area 50 of the printed product 32 _/ which in the case shown comprises two ink zones 44 of the printing press 1. The measuring bar 14 extends over almost the entire width of the printing press 1.

The modular construction of the measuring bar 14 provides several advantages _/ are particularly crucial for the use of the measuring bar 14 for obtaining image data _/ the one hand evaluated for an image inspection _/ are furthermore also used for a color measurement _/ particular for a color control _/ . Because the color measurement to be made on the image data of the highest requirements, especially with regard _/ must be ensured _/ that the same at all measurement locations starting conditions are present. In particular, it must be ensured _/ that the incident radiation intensity is the same at all measuring points.

Due to the modular structure, the measuring bar 14 can be brought very close to the object plane _/ that is to say to the surface of the printing cylinder 5 or the cooling rollers 24 carrying the printed product 32. Due to the close proximity of the object, the radiation intensity detected at the measuring points is also sufficiently high. Another advantage of the modular _/ immediate Measuring bar 14 placed close to the object is obvious: the influence of interference radiation is relatively small.

However, the modular structure also brings advantages in terms of adapting the dimension of the measuring bar 14 to any widths of the printing press 1 or to different printing formats. In addition, the parallel acquisition of image data in the individual measuring modules 27 of the measuring bar 14 and the possibly downstream receiving devices 16 and 38 has proven to be particularly advantageous with regard to subsequent processing of the image data: parallel processing or evaluation of the image data bears the high printing speeds and thus the correspondingly high amount of image data to be processed, especially the invoice.

In principle there are two embodiments of the measuring modules 27 of the measuring bar 14 either contains each meter module 27, both the optics _/ say, the lighting device 28 and the front lens 30 _/ and the Empfangsei nri rect (s) 16 _/ or the optics _28/30 is spatially separated from the receiving device 16. The connection between the measuring module 27 and the receiving device 16 then takes place via an image conductor 15.

6 shows a cross section through the measuring bar 14 according to the second version. In the measuring module 27, only the lighting device 28 and the front lens 30 are arranged, the measuring module 27 is connected to the corresponding receiving device 16 via image guide 15.

The separation of the optical from the electrical or electronic components brings several advantages. From a purely structural point of view, the measuring bar 14 can be reduced by separating the electronic components dimension. This takes up a small amount of space _/ which is particularly important when installed in the printing press 1. Further, the heat generation of the lighting device 28 can not adversely affect the temperaturemp indlichen CCD elements 38 and to the electronics _/ in particular the A / D converter _/ impact at a separation of the mechanical of the electrical parts. A decoupling Moreover, since the sources of interference extremely sensitive responsive elements of the Empfangsei nri rect (s) 16 and the further-processing electronics outside the printing press can for example be arranged under the footboard of the printing press 1 _/ _/ _/ easily integrates these elements of mechanical or electromagnetic interference to reach.

It has already been described above _/ that for a sufficiently accurate color measurement, the distance and geometric dependency of the measured values should be minimal _/ ideally zero, both with regard to the illumination and with regard to the observation. For this purpose, an elongated elliptical mirror 68 is provided _/ which produces a line-shaped image of the lighting device 28 on the printed product 32. Because of the favorable spectral reflection properties, the elliptical mirror 68 is optionally coated with chrome _/ or it is made of aluminum with a silicon oxide coating. This type of irradiation is optimally adapted to the measurement task _/ since this enables a highly homogeneous illumination in the defined image area 50 of the printed product 32 to be achieved.

In order to achieve in addition to the homogeneous lateral distribution of intensity within a defined image area 50 is also a constant distance from the printed product 32 from the measuring beam 14 _/ is within the measuring bar 14, a Blasluftrohr 45 with openings in the direction of Print product 32 provided. By means of the air-blowing position, the printed product 32 is held at a defined distance with respect to the lighting device 28 or the front optics 30. The feed means for the blown air to the Blasluftrohr 45 are that the blown air is used simultaneously for cooling the illumination devices 28 constructively designed so _/.

As already described _above , a homogeneous lateral distribution of the radiation within the defined image area 50 is of crucial importance for the subsequent color measurement or the subsequent color control. In particular, it must be ensured _/ that changes due to a difference of the image areas defined Aüsleuchtung 50 lie on the sheet 32 within the permissible color tolerances. As soon as these changes lead to errors _/ which exceed the color tolerances _/ a highly precise _/ defined color measurement is no longer possible. In addition to a homogeneous illumination of the defined image area, it must therefore also be ensured _/ that in the case of a modular measuring bar, the lighting devices 28 are reliably _/ coordinatedly controlled.

2. Lamp control

With regard to the lighting devices 28, it must be ensured _/ that they expose the printed product 32 to radiation _/ which has a temporally constant _/ spectral composition. In addition, the radiation intensity should be relevant throughout

Wavelength range _/ which lies between approx. 400 nm and NIR _/ be somewhat the same. Another requirement _/ which is to be placed on the illumination devices 28 _/ consists of _/ that the spectrum of the radiation must be independent of the respective measurement location on the printed product 32nd Only if the spectrum of the radiation is the same at any measuring location is _/ can be used for any measurement location same spectral correction function _/ say the same Farbfi lter _/ are used 36th

Therefore, precision halogen lamps are advantageously used as lighting devices 28 _/ wherein a precision halogen lamp is provided for each measuring module 27. In order to achieve at a central arrangement (center of the selected range) of the lighting devices similar illumination even in the two edge zones of the printed product 32 _/ are jewei ls arranged left and right in the edge regions of the measuring bar 14, two more precision halogen lamps. To prevent _/ that the scattered light distorted uncontrollably of adjacent illumination devices 28, the measurement results within a defined image area 50 is _/ are provided in the beam path covers _/ that only the image region defined is illuminated by the illumination device 28 of the associated measuring module 27 which are arranged so _/.

The precision halogen lamps are compared with each other by separate programmable precision current sources _/ the current sources are controlled via field effect transistors. The lamp control 61 takes place on the basis of the color temperature of the individual lighting devices 28.

The structure of a lamp control is shown in Fig. 7a. The light from an illumination device 28 is coupled to a light guide 64 _/ the output of which is connected directly to the input of the corresponding image guide 15. The radiation from each of the light guides 64 passes through the associated optical system 33 to the

Receiving devices 16 and 38, respectively. Since the light is measured in each of the spectral channels, a vector of discrete values becomes _/ for each lighting device 28 provided. This vector is normalized with the corresponding measured values of a standard li chtque l le 47. The change in the standardized measured values is correlated with the temperature T. In particular, the standardized measured values can be plotted against the corresponding color channels. In a first approximation, the relative intensities change as a function of the temperature T. The current of the associated lighting device 28 is now controlled via an inverting amplifier 69. Through the lamp control 61 is thus ensured _/ that each of said lighting devices emits radiation 28 the same intensity throughout the relevant spectral region.

The light guide 64 is advantageously arranged in a bore 70 _/ the axis of which is directed towards the lighting device 28. Furthermore, the light guide 64 is adjustable within this bore 70.

FIG. 7 b shows a cross section through one of the image guides 15 _/ in particular the coupling area for monitoring the lighting device 28 _/ or for the calibration to the absolute white or the calibration white 47 is shown. The image guide 15 consists of a multiplicity of bundled light fibers 49. On one side of the image guide 15 there is an area for coupling in the radiation from the light guide 64 or for calibration on the calibration white 47.

The current _/ measured and averaged value of each lighting device 28 (white value) is used to standardize the color measurement values; the currently averaged dark current of the CCD lines 38 is subtracted from this. This measure achieves a correction which is of great importance for a reliable color measurement. The correction can be described as follows:

Max

Y i * Y. - dark max i i = 1

Y =

Y - Y white value dark

Max

White level =

White value max j = 1

Max

Dark =

Darkness l max j = 1 where Y denotes the measured values of the Y channel _/ i the number of pixels of an interconnected color measurement area _/

Y the white value of the lighting device 28 and white value

Y the dark current of the CCD lines 38. Dark

Measuring bar protection with calibration function

For the regulation of the inking by colorimetric quantities, it is indispensable _/ Bi lderfassungseinrichtung 12 to an absolute white or to calibrate a calibration white 47th According to DIN, the Absolutweiß 47 is barium sulfate _/ which, due to its consistency - usually a compressed powder tablet - is not very suitable for inline use. A tile is therefore used as a substitute used _/ whose optical properties relative to barium sulfate are known. The calibration white 47 must be dimensioned so that it can be used by everyone

Illumination device 28 can be measured. Thus, one embodiment proposes _/ that the calibration white 47 is on the surface of the cylinder 5 _/ or that the calibration white is housed on a separate carrier in the channel of the respective cylinder 5, 24 47 according to. In particular, care must be taken _/ the distance between the illumination device 28 and calibration White 47 is the same as the distance between the illumination means 28 and defined image area 50 on the printed product 32 is usually carried out a calibration of the Bi Iderfassungseinri rect ^"12 in print pauses. When accommodating the calibration white In the channel of the cylinder 5, in the case of a sheet-fed printing press, however, the calibration can also take place during the ongoing printing process.

A particularly advantageous embodiment with regard to a calibration of the image capturing devices 12 or the measuring modules 27 can be realized as follows. This embodiment is shown in FIGS. 8a) and 8b). The measuring bar 14 with the measuring modules 27 is arranged opposite the impression cylinder 5. A protective housing 46 is assigned to the measuring bar 14. Measuring bar 14 and protective housing 46 have a common axis, a so-called mounting tube 48. The measuring bar 14 is pivotally mounted about the axis and can be locked in two positions, a measuring position (FIG. 8a) and a parking position (FIG. 8b). In the measuring position, the printed product 32 is scanned on the printing cylinder 5. Illumination device 28 and front optics 30 are arranged at an angle of approximately 45 °. The radiation advantageously falls

Illumination device 28 at an angle of 45 ° to the surface of the printed product 32. During printing breaks, the measuring bar 14 is pivoted into the park position and is now located within the protective housing 46. The pivoting of the measuring bar 14 into the protective housing 46 brings several advantages with it. Thus, by swiveling away, space is created in the area of the cylinders 4, 5 of the printing unit 2. As a result, the cylinders 4, 5 are more freely accessible, which proves to be advantageous as soon as the cylinders, but in particular the rubber blanket of the rubber blanket cylinder 4, have to be cleaned. By pivoting the measuring bar 14 into the protective housing 46, the lighting devices 28 and the front lenses 30 are also protected from contamination. In particular, no detergent that is used to clean the rubber cloth cylinder 4 during the printing breaks reaches the optical parts.

The following configuration is particularly advantageous, in which the calibration white 47 is arranged within the protective housing 46 in such a way that its measurement can take place in the parking position of the measuring bar 14 in the protective housing 46. Now the optical intersection of the respective lighting device 28 and the front optics 30 lies on the surface of the calibration white 47. It is only necessary to note that the dimensioning of the protective housing 46 is selected so that the distance of the lighting device 28 to the calibration white 47 in the park position corresponds to the distance corresponds to the lighting device 28 to the measuring point on the printed sheet 32.

9 shows a schematic illustration of a first embodiment of the device according to the invention. Each measuring module 27 of the measuring bar 14 scans a defined image area 50 on the printed product 32 line by line. In the case shown, the defined image area 50 comprises two color zones 44. The radiation from the lighting device 28, which is reflected by the surface of the printed product 32, is from the front lenses 30 on the corresponding image guide 15 or imaged. The image guides 15 arranged in parallel on the image side are layered one above the other on the receiving side at a defined distance. Advantageously, the layered image conductors 15 are assembled on the receiving side to form an arbitrarily variable plug connector 31.

The image conductor ends stacked one above the other at a defined distance are then imaged onto the receiving devices 38 via an optical system 33 consisting of a receiving objective 34, a color beam splitter 35 and a color filter 36. The Farbfi ltern 36 are color filters, which in the illustrated case, for. B. the X, Y and Z range for color measurement according to the three-range method (DIN 5033) and an additional filter that hides a near infrared (NIR) range for the separate measurement of printing black from the spectrum of the measurement radiation. Both the beam splitter 35 and the color filter 36 are designed in such a way that high sensitivity to light and good optical imaging properties are achieved in each of the three color channels X, Y, Z.

In order to guarantee comparable filter behavior for all pixels, the color filters 36 are arranged in the parallel beam path of two lenses, which ensures that the color filters 36 are always penetrated vertically by the radiation. This measure proves to be extremely advantageous with regard to reliable color measurement and control.

Due to the division of the image capturing device 12 into a single measuring module 27 carrying measuring bar 14 and a receiving device 16, the sensitive sensor system and the electronic further processing of the image data are spatially distant from the measuring location. The thermal load at the measuring location, the inevitably exists due to the lighting devices 28, so it cannot have a negative effect on the temperature-sensitive elements, in particular also on the A / D converter and the CCD elements 38.

In addition, the modular optical beam path, which is constructed with image guides, serves to keep the optical components as small as possible. On the one hand, the lenses at the measuring point are only slightly larger than the measuring strips on the measuring side, so they are light and enable a slim design of the measuring bar. On the other hand, the image conductor tapes can be stacked so tightly that the stack as a whole is rectangular, particularly advantageously of almost square shape. With this arrangement, the sensor-side lenses can also be kept small, which enables cost-effective vibration isolation. Furthermore, the sensors themselves can also remain small, so that they can be cooled with simple means.

The image guides 15, which transmit the radiation remitted by the printed product 32 from the selected areas 50, are either single-layer or multi-layer. Each image guide 15 itself is composed of a large number of light fibers 49 that are next to one another and possibly one above the other, which are arranged in such a way that geometrically undisturbed image transmission is ensured. Each single-layer or multi-layer multiple image conductor 15 is usually composed of a plurality of layers lying one on top of the other, wherein one layer can usually be provided for each color channel.

A particularly advantageous embodiment of an image guide 15 is a so-called multi-layer “single image guide”, the individual layers being stacked one above the other on the input side and being split on the receiving side and the Map selected image area 50 directly onto correspondingly assigned CCD lines 38. With regard to the stacking of the image conductor ends to form a connector, there are basically two options:

1. The individual image conductors _/ which transmit the radiation from the defined image area 50 _/ are stacked one above the other _/ ie a plug connector 31 is composed of image conductors 15 stacked one above the other. The radiation _/ which is present at the output of the connector 31 is then passed through a beam splitter 35 and corresponding color filter 36. The advantage of such an embodiment lies in the fact that the measuring light of each multilayer single image guide 15 comes from exactly the same defined image area 50.

2. A second possibility of end-stacking images is that the individual color channels of all image conductors 15 are combined in blocks, which in turn are then stacked to form a plug connector 31. With this type of arrangement, the subsequent beam splitting - and thus the beam splitter 35 - can be omitted. However, this solution has the disadvantage that the measuring light in the individual color channels does not come from exactly the same image areas 50.

11 shows a geometrical and optical design of the image transmission path according to the device according to the invention; a defined image area 50, which in the case shown comprises two color zones 44, is imaged on an image guide 15 via a front lens 30. A white reference 29 is coupled separately onto the image guide 15. More information about this

White reference coupling n 29 were given in connection with FIGS. 7a) and 7b). The image guide 15 consists of side by side and superimposed light fibers 49, which are arranged in such a way that a geometrically undisturbed image transmission is guaranteed, ie certain areas of the image guide 15 each transmit the image of a certain partial area (image point) 1,..., N of a color zone 44.

The image conductors 15 arranged in parallel are layered on their output side at a defined distance above one another. The image conductors 15 form a regular layer structure in the plug connector 31. This connector 31 is designed such that any number of image conductors 15 can be joined together without any problems. The ends of the image conductors 15 are imaged via an optical system 33 onto a structure of CCD lines 38 arranged one above the other which is optimally adapted to the regular layer structure of the plug connector 31. At the output of the CCD area array 16 there are data which are further used by the computing device 17 for image inspection and for color measurement.

In order to achieve a reliable adaptation of the stacked ends of the image conductor 15 in the connector 31 to the CCD row arrays 38, an opto-mechanical coupling member 52 is advantageously arranged between the connector 31 and the optical system 33. This opto-mechanical coupling element 52 is described in more detail in FIG. 12.

The ends of the image conductors 15 are arranged in the plug connector 31, the ends of the image conductors 15 carrying image information are mapped onto the CCD line arrays 38 via the optical system 33. The ends of the image guide 15 act as image apertures. In the case of a single-layer single-image conductor 15, a narrow strip of the printed image is detected in each case, which is applied to the optical system 33 CCD line arrays 38 is imaged. A division into the individual color channels takes place by means of a beam splitter 35 which is arranged in the optical system 33. As already described above, the beam splitter 35 can possibly be omitted in the case of a multi-layer single or multiple image guide 15. Here, each individual layer of the image conductor 15 is mapped onto a corresponding CCD line array 38 via a corresponding color filter 36.

In order to adapt the geometries of the image conductor ends stacked in the plug connector 31 to the geometries of the CCD lines or the CCD line arrays 38, the coupling element 52 is proposed. This coupling member 52 consists of a front block 53 and a rear block 55 _/ both of which are connected to one another via light guides 54. While the front block 53 is adapted to the geometry of the image guide stack _/ the rear side block 55 has the geometry of the CCD row arrays 38. In terms of production technology, the coupling member 52 is easier to handle than the relatively long image conductors 52 _/ which connect the measuring bar 14 to the receiving unit 16. Furthermore, due to the optical imaging laws, the geometry of the CCD line array 38 is linked to the geometry of the image conductor stack (plug connector 31) via the imaging scale of the optical system 33. These three components provide so with respect to their geometric dimensions of a coupled system is Da is not secured in the general _/ the geometrical dimensions of the three components _{_31/33/38} fit to one another -. Approximately consist of technological or economic reasons, upper and lower limits for the Dimensioning of these components _/ or it may be economically sensible _/ not to choose the connector 31 in the size matching the illustration, but rather larger - the coupling member 52 proves to be extremely useful and useful. 10a) _/ 10b) and 10c) an already described quadruple conductor is outlined according to an embodiment of the device according to the invention. 10a) shows a side view of the quadruple image conductor. The front objective 30 images the defined image area 50 on the image guide 15 consisting of several layers _/ whereby four narrow strips of the printed image 32 are simultaneously imaged on the image guide 15. The ends of the image conductors 15 are stacked one above the other in a manner previously described in a connector 31 and then mapped via an optical system 33 to correspondingly arranged CCD line arrays 38.

10b) shows a cross section of the quadruple image guide in direction A from FIG. 10a). The image guide 15 consists of several layers _/ which are arranged at a precisely defined distance from one another. The image conductor layers themselves are each composed of a plurality of adjacently ordered optical fibers 49 together _/ are arranged so _/ that an optimal image transfer is ensured.

In Fig. 10c) the beam path is at one

Quad image guide shown. The defined image area 50 is imaged on the CCD line array 38 via a front optical system 30 _/ image guide 15 and an optical system 33 with a defined imaging scale.

As already mentioned several times _/ in some configurations of the device according to the invention, a beam splitter 35 must be provided in the optical system 33 _/ which divides the radiation originating from the defined image areas 50 into individual color channels X, Y, Z and IR.

Such a beam splitter 35 is shown in a side view in FIG. 13a. The image conductors 15 stacked one above the other on the reception side carry the image information from FIGS individual measuring ranges. The ^'fester of the Bildt 15 transmitted radiation kills aufgespli in multiple channels. An edge filter 71 is arranged in front of the actual receiving lens 34, which filters out an IR channel and images it on a CCD line 38. The remaining radiation is split into an X, a Y and a Z channel and mapped via color filters 36 and corresponding optics to the associated CCD lines 38.

13b shows a further embodiment of a beam splitter 35 in a side view. The image conductors 15 stacked one above the other on the receiving side carry the image information from the individual measuring ranges of the selected region 50. The beam splitter is designed in such a way that it transmits the radiation transmitted by the image conductors 15 into the three color channels (X, Y, Z) and split the IR channel. The radiation from the individual color channels is imaged via corresponding color filters 36 or an NIR filter 36 on correspondingly assigned CCD lines 38.

14 shows the measurement geometry and the beam path in a measurement module 27. From one

Illumination device 28 strikes the radiation via imaging optics 56 on the selected defined image area 50 of the printed product 32. The angle of incidence of the radiation is 45 °. The radiation remitted on the printed product is imaged onto a receiving device 16 via an optical receiving system 57. The receiving device 16 observes the defined area 50 of the printed product 32 at an angle of 0 °.

15 shows a first embodiment of a measuring module 27 with an integrated receiving device 16. From the illuminating device 28, the radiation falls via a cross-sectional converter 73 and a cylindrical mirror 72 onto the defined area 50 of the printed product 32 Irradiation takes place at an angle of incidence of 45 °, while the observation takes place perpendicular to the measuring plane. The radiation remitted at the defined image area 50 is split into individual color channels via a beam splitter 35. Each color channel is mapped onto a CCD line 38 via color filters 36 and receiving optics 34. The NIR channel, which is also usually provided, for measuring the black component is not shown separately in FIG. 15.

It was previously mentioned that the CCD lines, like the processing electronics, are very sensitive to temperature fluctuations. Since in the example shown the measuring module 27 contains both the optical and the electronic elements, a light source is chosen for the lighting, the light from an lighting device 28 via a cross-section converter 73 (light conductor optics) onto the Cylinder mirror 72 is passed.

A further embodiment of a measuring module 27 with an integrated receiving device 16 is shown in FIG. 16. The structure is similar to that shown in FIG. 16, but is optimized with regard to the channel geometry. From a lighting device 28, which in turn is a cold light source, the radiation is irradiated via a cross-sectional converter 73 directly onto the defined image area 59 of the printed product 32. Again, the radiation from the defined image area 50 of the printed product 32 is measured in color measuring channels X, Y, Z at different angles. In particular, the Z channel lies in the direction perpendicular to the measuring plane. Since the spectral sensitivities of the Z channel and the NIR channel have no overlap area, but are far apart, a color divider 74 is brought into this channel. This color splitter 74 passes the spectral range belonging to the Z channel, while the spectral range above is reflected on the NIR channel. The The defined image area 50 is imaged on the CCD line arrays 38 via color filters 36 and receiving optics 34.

The construction of a measuring module 27 according to FIG. 16 has proven to be particularly advantageous in order to counteract a falsification of the measured values by the fact that the radiation remitted on the printed product 32 usually shows a peak in the direction of the specularly reflected radiation component. The surface of the printed product 32 is therefore normally not an ideally scattering surface which scatters the radiation with the same intensity in all solid angle regions. Rather, the intensity of the surface of the

Printed product 32 remitted radiation depending on the angle. The reasons for the increased radiation intensity in the direction of the specularly reflected radiation component lie in the nature of the paper, the color density, the area coverage and the type of printing ink.

A further falsification of measured values as a result of an increased radiation intensity in the direction of the specularly reflected radiation component is caused by the fact that the freshly printed sheets may not yet have dried completely. In order to avoid falsification of measured values due to moisture components on the surface of the printed product 32, it is provided that polarization filters 75 are introduced into the beam path.

17 shows a further embodiment of a measuring module 27, the illustration being limited to the receiving device 16 for the radiation. The radiation remitted by the selected area 50 of the printed product 32 is imaged on a lens array 76 via color filters 36. A pixel of the defined image area 50 is received and subsequently by the lens array 76 imaged onto the adjustable CCD receiving elements 38 via optical fibers 54 and an imaging system 33. This fiber-optic embodiment of the measuring module 27 in particular also opens up the possibility of using individual light fibers 54 for the reference value coupling (white reference of the illumination device 28 or else the calibration white reference). Furthermore, the glass fiber bundle can be used to adapt the geometry between the defined image area 50 and the receiving device 38 without any problems.

18 shows a further embodiment of an image detection device 12. Again, the optics, in particular the lighting device 28 and the front lens 30, and the receiving device 16 are positioned in a measuring module 27. The lighting device 28, not shown, illuminates the defined image area 50. An intermediate image is generated via a front lens 30 and is mapped onto a CCD line array 38 via a further optical system 33. The optical system 33 is a bi Id lens and a receiver side lens, in the common focus of which a partia filter 66 is positioned. The 4-f arrangement eliminates the spatial dependence of the radiation between the lenses, which enables the use of a partial filter 66. The use of a partial filter 66, which is introduced into the beam path on the receiving side, has several advantages:

- a more precise adjustment is possible,

- higher transmission rates can be achieved,

- The size of the intermediate image can be freely selected by using a two-stage image. Therefore, the reception-side image can always be dimensioned so that the required image scale is obtained. In order to rule out uncontrollable color measurement errors, the radiation must - as mentioned before - pass through the filter vertically. Otherwise, the spectral transmission is a non-linear function of the angle of incidence. The result of this is that the spectral profile of the filter does not correspond to the normal spectral value function X, Y, Z after normalization - the color measurement is therefore dependent on the angle. In order to eliminate these errors, the above-mentioned 4-f arrangement of the lenses is selected.

A partia ifi 66 usually consists of a neutral glass onto which a multiplicity of different color filters 36 are cemented. The resulting spectral profile results from the interaction of the individual sub-filters of Partia Ifi Iters 66. The additional use of diaphragms and masks enables the area components of the individual sub-filters to be switched on or off in a defined manner, so that the spectral profile can be influenced in a targeted manner.

19 shows a further embodiment of the device according to the invention. In this embodiment, the receiving device 38 can either be integrated in the measuring module 27, but both can also be arranged separately from one another via image conductors 15.

The radiation remitted from the selected area 50 of the printed product 32 is transmitted via a front objective 30 and a slit diaphragm 79 and from there via a lens, e.g. B. a cylindrical lens 80 directed to a prism 78 or grating. The prism 78 spectrally decomposes each measuring point of the selected area 50. The receiving device 38 consists, for example, of a cell-shaped CCD element, the number of CCD elements corresponding to the number of support points in the spectrum. Since spectral decomposition takes place for each measuring point of the selected area 50, the receiving device 38 advantageously consists of one CCD array, the number of lines of which corresponds to the number of support points in the spectrum and the number of columns of which corresponds to the number of measuring points within the selected range 50. In order to achieve a higher processing speed, the CCD array can consist of several CCD lines, the individual CCD lines being read out in parallel. With this spatially resolved spectrometer camera, both a spectral and a spatial resolution can be achieved.

A disadvantage of the previously described devices in this embodiment is the increased number of CCD elements. However, this additional effort is compensated for by a lower resolution with regard to the digitization of the data. While 12-bit data must be available for a reliable color measurement in the previously described embodiments, the same result can be achieved here with e.g. B. achieve 8-bit image data.

Another advantage of this embodiment is that the spectral, digital image data can be adapted to any filter function by weighting with a corresponding factor. This simulation of any filter functions (X, Y, Z or RGB) in the digital area can save the usual "hardware" filters. While the use of filters 36 must always ensure that both a homogeneous illumination of the selected area 50 and a well-defined object width are maintained, these things play a much smaller role in the embodiment described in FIG. 20.

The individual system components of the image capturing device 12, which are shown in FIG. 4, are described in more detail below. As already described in detail above, the receiving device 16 consists, among other things, of the CCD line array 38. This CCD line array 38 consists of the CCD lines assigned to the individual color channels with corresponding control electronics 40. Each of the CCD lines 38 is on an adjustable and exchangeable chip carrier housed, which also contains clock drivers and video preamplifiers not shown separately. The control electronics 40 for the four CCD line arrays 38 (X, Y, Z, NIR) carry out the usual physical process of signal formation within a CCD line 38. The process includes the following steps: charge generation, charge transport, charge detection and amplification. A double correlated sampling of the amplified signal is then carried out. The signal is converted into a digital image, for example, using a 12 bit A / D converter 39. The trigger electronics 60 ensure the synchronization of the

Image capture device 12 with the angular position of the printing unit 2. From the pulse sequence of a rotary angle sensor 13, in particular an incremental sensor, both the angular speed of the cylinder 5 is determined and the integration cycle for the CCD lines 38 is generated as a function of the measured printing speed.

Precondition for reliable synchronization with regard to reading out the image data of the receiving units 16 at the correct angle is precise knowledge of the angular distances between the incremental markings of the respective incremental encoder 13 Interval between two

Incremental pulses for determining the speed of the printing press 1 are derived. The image data of the receiving devices 16 are forwarded to the computing device 17. The computing device 17 processes the image data in real time. Because of the very high amount of image data (depending on the printing speed), there is a need for multi-level data reduction. The following functions are implemented in the computing device 17:

- Storage of the target image;

- Management of a parameter image with control information for defining the image format, weight functions for evaluating image errors and the image areas in which color measurements are to be carried out;

- Accumulation of scanning lines in the measuring lines;

- Storage of the pixels of the digital image relevant for the color and shading measurement as a list;

- fast transfer of image data via a pipeline bus;

- accumulation of the difference images;

- synchronization of the CCD lines;

- parallel evaluation of the current and accumulated difference image with differently adapted thresholds;

- Error preprocessing for image inspection in real time.

The computing device 17 consists of several hardware components:

- an assembly that takes over the signal processing (shading correction, combining scanning to measuring lines),

a memory for data in which the measured values for color measurement / control can be stored,

a control circuit which, depending on the content of a parameter memory, sorts measurement data for color measurement / control into the memory described above,

- An assembly mainly for image inspection, which contains the target image memory, parameter memory and accumulating difference image memory, which also weighs differences depending on the parameter memory can form both for the current difference image as well as for the accumulated difference image,

- A circuit which switches a hardware signal when the tolerance is exceeded, which z. B. can serve for real-time control of a waste paper switch and

- A module that contains a CPU that controls communication with higher-level modules, or can access the above memory of the color measurement values, in order to calculate further derived data from the "raw" data.

The computing device 17 has several defined interfaces, via which communication with the machine control 21 of the input device 19 and the offline measuring device 20 is made possible.

Processing the image data in real time means that an operation is always complete when the same operation has to be processed again, for example cyclically. A difference image is thus generated in real time if the difference image is calculated from the current image and the static, predetermined target image before the next current image is present. The same applies to the evaluation of the color measurement data. The evaluation of the color measurement data takes place in real time when the evaluation is also completed before the corresponding data set of the next image is ready for processing. The processing cycle is therefore directly linked to the cyclical printing of the printed products 32 and thus to the speed of the printing press 1. Since both the image inspection and a color measurement take place in real time, the print product 32 just created can be assessed according to whether its print quality is sufficient or not. Corresponding corrective measures can be initiated immediately, so that the printing of faulty sheets is reduced to a minimum. The amount of data or data rate depends on the pixel size, the format of the print image 32 and the speed of the printing press 1. The computing device 17 must be adapted to this amount of data with regard to the memory requirement and the processing speed. In particular, the memories which are not shown separately in the figures must be designed in such a way that a plurality of mutually independent sets of image data can be stored in them.

According to the invention, an image inspection is carried out on the basis of the image data of the entire printed product and a color control is carried out on the basis of selected image areas. With regard to the image inspection, an inspection is carried out in the accumulated difference image, which in particular recognizes printing errors that are constant over time. On the basis of the results in the current and in the accumulated difference image, an evaluation of the error characteristic is derived. In particular, this makes it possible to eliminate statistical errors from errors which have a massive influence on the print quality, such as e.g. B. slugs to distinguish.

The data of a preferably coherent, print quality-determining region of each color zone 44 are interconnected by the above circuit with computing device 17. In the case of colorimetric control, the actual color location of this area is determined and compared with a corresponding stored target color location. An embodiment of such a colorimetric control is - as already mentioned - described in EP 0 324 718 A1. If there is a color difference between the actual and the target color location, the corresponding changes in layer thickness in the corresponding color zones 44 of the individual printing units 2 are calculated. The corresponding setting data for the ink actuators are sent to the respective printing units 2 via a machine control 21. A corresponding Machine control 21, which is used in particular to regulate the ink control elements of a printing press 1, has become known from EP 0 095 649 B1. A machine control 21 on the printing press 1, which is used, for example, for the automatic positioning of a slug catcher, is described in DE 37 08 925 A1. These two documents are to be regarded as integral parts of the present patent application.

Claims

claims

1. Device for image inspection and color measurement on at least one printed product that was created in a printing press with at least one printing unit, characterized in that the device consists of at least one image capture device (12) that supplies image data from the printed product (32) and from a computing device ( 17), the computing device (17) on the one hand determines all image data of the printed product (32) for the purpose of an image inspection, and on the other hand determines a measurement variable for a color assessment from the image data of at least one measuring point (pixel) of the printed product (32).

2. Apparatus according to claim 1, d a d u r c h g e k e n n z e i c h n e t that a display means (26) is provided which displays the measured variables determined.

3. Device according to claim 1, characterized in _/ that the image data determined are used as controlled variables for an image inspection and / or as controlled variables for color control in the individual printing units (2) of the printing machine (1).

4. The device according to claim 1, characterized in that in the printing press (1) at least one rotation angle encoder (13) and in a web printing press possibly a sensor (23) is provided for detecting the beginning of the web section and that a trigger electronics (60) the

Image capture device (12) controls so that it provides image data of the entire printed product (32).

5. Device according to claim 1, characterized in _/ that the image capture device (12) is used offline and is arranged above a storage device for the printed product (32).

6. The device according to claim 1 and 5, characterized in _/ that the image capture device (12) consists of one or more measuring modules C27) and at least one associated receiving device (16).

7. Apparatus according to claim 6, characterized in _/ that the measuring modules are arranged in a measuring bar (14) (27), a measuring module (27) each have a defined image area (50) - at least one ink zone (44) - of the printed product (32) scans.

8. The device according to claim 6, characterized in _/ that the measuring modules (27) are spatially separated from the image data generating receiving device (16) and connected to it via image conductors (15).

9. The device according to claim 6, characterized in _/ that the measuring modules (27) and the image data generating receiving devices (16) in the measuring bar (14) are integrated.

10. The device according to claim 8 or 9, - characterized in _/ that the measuring bar (14) is modular, wherein each measuring module (27) delivers the reflectance values or the image data from a defined image area (50).

11. The device according to claim 1 and 8 or 1 and 9, characterized _{/ in} that each measuring module (27) at least one

Lighting device (28) and a front lens (30) are assigned, which image the defined image area (50) on at least one cell-shaped image guide (15) (single image guide), with a corresponding number if there are several image guides (15) per measuring module (27) (multiple image guide) cellular image conductor (15) is layered one above the other.

12. Apparatus according to claim 11, characterized in _/ that the lines on the image side shaped and possibly parallel layered, cellular image guide (15) are stacked on the receiving side at a defined distance above the other (regular layer structure).

13. Apparatus according to claim 11, characterized in _/ that the image conductor (15) are joined together to form a regular layer structure on the receiving side, wherein in each case exactly the associated (n) image guide is contained in a layer (15) (die) a measuring module (27) (are).

14. The apparatus according to claim 12 and 13, characterized in _/ that the image conductors (15) on the receiving side to an optical connector (31) are assembled.

15. The apparatus of claim 6 and 12 or according to 6 and 13, characterized _{/ in} that the outputs of the optical connector (31) via an optical system (33) on at least one receiving device (16) are mapped.

16. The apparatus according to claim 15, characterized in _/ that the receiving device (s) (16) consist of a number at a defined distance parallel to each other arranged photosensitive elements, the number of which determines the spatial resolution of the image capture device (12).

17. The apparatus according to claim 16, characterized in _/ that the receiving device (16) from an at least the number of measuring modules (27) corresponding number of CCD lines (38) or CCD-line arrays (38) and from a control electronics (40th ) consists.

18. The apparatus according to claim 12, characterized in _/ that the optical system (33) is an optical relay system and each of a first receiving lens (34), a color beam splitter (35) and in each case a further receiving lens (37) per color (X, Y, Z, NIR), which map the corresponding color channels to a corresponding number of receiving devices (16).

19. The apparatus according to claim 13, characterized in _/ that the optical system (33) consists of lenses (34, 37) and color filters (36), which the color channels of the individual measuring modules (27) corresponding outputs of the connector (31) to a corresponding Show number of receiving devices (16).

20. The apparatus according to claim 11, dadurchgekennzeichne _/ that the output of the image conductor (15) is followed by a field diaphragm (62) with a plurality of gap-shaped openings (63).

21. The apparatus according to claim 20, characterized in _/ that the field diaphragm (62) between the position of the image information and the position of the white reference of the lighting devices (28) of the measuring modules (27) has a darkened area.

22. The apparatus of claim 20 and 21, characterized _{/ in} that the cross section of the image guide (15) is larger than the field diaphragm (62) and that the input of each image guide (15) with respect to the optical axis of the first lens (34) on the receiving side of the Image guide (15) is adjustable in a holder.

23. The device according to claim 18, characterized in _/ that the optical relay system (33) contains two lenses which are arranged so that. the interspace is irradiated almost in parallel.

24. An apparatus according to claim 22, characterized in _/ that the color filters (36) are made in the optical relay system (33) consists of several different filter parts (Partialf1 Iter) which can be displaced in relation to the field stop (62).

25. The apparatus of claim 15 or 16, characterized in that the receiving devices (16) and the CCD lines (38) each consist of a chip with several parallel parts and that the pixel height is greater than the height of the image of the scanning lines on the sensor is.

26. The device according to one or more of the preceding claims, characterized in _/ that the receiving means (16) and the CCD line are cooled (38).

27. The apparatus of claim 13 and 16 or 14 and 16, characterized in that a coupling member (52) is provided between the connector (31) and the receiving device (16), the opto-mechanically the geometric dimension of the stacked outputs of the image conductors (15) adapts to the geometric dimension of the receiving device (16) or the CCD line array (38).

28. The apparatus according to claim 27, characterized _{/ in} that the coupling member (52) from a front block (53), the geometric dimension of the stacked outputs of the image conductors. (15) corresponds to and from one to the geometry of the

Receiving device (16) adapted rear side block (55), and that the front block (53) and the rear side block (55) are connected via image conductors (15), the number of which corresponds to the number of image conductors (15) that exist between the measuring modules (27) and the receiving device (16) are provided.

29. The apparatus of claim 1 and 7, characterized in _/ that in each measuring module (27)

Lighting device (28) with a mirror (58, 72) for illuminating the defined image area (50) and a front lens system (30) for imaging the defined image area (50) on the image guide (15) is provided.

30. The device according to claim 29, characterized in _/ that the mirrors (72) are designed as elliptical mirrors (68).

31. The device according to claim 29, characterized in _/ that the radiation of each illumination device (28) is coupled to a respective light guide (64) whose output is connected directly to the corresponding image conductor (15) and is measured in each of the color channels, so that Color measurement values are provided for each lighting device (28), which are standardized to the corresponding values of a standard radiator (47).

32. Apparatus according to claim 30, characterized in _/ that a lamp control (61) is provided, which sets the current for the illumination devices (28) that the radiation intensity is calibrated to each other.

33. Apparatus according to claim 30, characterized in _/ that the light guide (64) is arranged in a bore (70), the axis of which is directed towards the lighting device (28), and that the light guide C64) axially within this

Bore (70) is displaceable.

34. Apparatus according to claim 30, characterized in _/ that the computing device (17) according to the formula of the white level of each illumination means (28) uses the currently measured in each color channel and averaged value for normalization of the color values and subtracted therefrom the currently averaged dark current:

i max

i * Y. - ^Y dark max ii = 1

Y = n

^Y white level ~ ^Y dark

^• 'max

γ _white _value ₌ _ γ _{white value}

- "max j = 1 Max

Y dark = ¹ Y dark

^• 'max j = 1

where i is the number of pixels of the color measurement area, Y is the

Measured values of the Y channel, Y the white value of the

White level lighting device and Y the dark current of the

Dark CCD lines j characterized.

35. Apparatus according to claim 30, characterized in _/ that it is in the standard radiator (47) is a calibration white.

36. Apparatus according to claim 1 and 6, characterized _{/ in} that the image capturing device (12) in a sheet-fed rotary printing press is preferably assigned to the printing cylinder (5) of the last printing unit (2) or additionally to that in front of the reversing drum (10) if the sheet-fed printing press in Schδn- and back pressure operation works.

37. The apparatus of claim 1 and 6, characterized in _/ that are provided in a roller rotary printing machine, two image capturing means (12) for double-sided scanning of the printed web (32).

38. Apparatus according to claim 33 or 34, characterized in that blowing air devices (45) are provided on the measuring bar (14).

39. Apparatus according to claim 38, characterized in _/ that the measuring bar (14) or in one of the measuring bar (14) associated with the protective housing (46) a

Blown air device (45) is arranged, the blown air stream directed towards the printed product (32) simultaneously serving to cool the lighting devices (28) of the measuring modules (27).

40. Apparatus according to claim 35 and 36 or 35 and 37, characterized _{/ in} that the calibration white (47) on a separate carrier in the channel (65) of the respective cylinder (-5, 10), with respect to which the measurement is carried out, or on the Cylinder (5, 10) itself, preferably over the entire length of the cylinder (5, 10), is arranged.

41. Apparatus according to claim 1 and 7, characterized in _/ that the measuring bar (14) is pivotally mounted and can be locked in a measuring position and in a parking position.

42. Apparatus according to claim 7 and 41, so that the measuring bar (14) can be locked in two positions with respect to a protective housing (46) and that the measuring bar (14) is arranged at least in the park position in the protective housing (46).

43. The apparatus of claim 35 and 42, characterized in _/ that the calibration white (47) in the protective housing (46), preferably the entire length of the measuring bar (14) is arranged and that a standardization to the calibration white (47) in the park position of the measuring bar (14) can be carried out.

44. Apparatus according to claim 11, d a d u r c h g e k e n n z e i c h n e t that the lighting device (28) directly or indirectly

Radiates in the defined image area (50) and that the remitted radiation via an optical

System (33) is mapped to receiving devices (16).

45. Device according to claim 44, so that the optical system (33) contains a beam splitter (35), the individual outputs of which are assigned optical filters (36) with imaging optics (37).

46. Apparatus according to claim 44, so that the optical system (33) contains color filters (36) and imaging optics (37) which lie outside the vertical direction of observation with respect to the illumination / measurement plane.

47. Apparatus according to claim 44, characterized in _/ that the optical system (33) one

Contains partial filter (66), which is arranged in the common focus of two lenses.

48. Apparatus according to claim 8 and 44 or 9 and 44, characterized in _/ that the optical system (33) contains a prism (78) or a grating.

49. Apparatus according to claim 48, so that the computing device (17) weights spectral measured values such that any filter functions are simulated.

50. Apparatus according to claim 44, characterized in _/ that the optical system comprises (33) color filter (36) and that the individual color channels are mapped to the lens array (76).

51. Device according to one or more of the preceding claims, characterized in _/ that the outputs of the color channels in each case on at least one row or arrayfδrmiges receiving element (16, 38) are mapped.

52. Apparatus according to claim 1, characterized in _/ that the computing device (17) the image data of the receiving means (16, 38) and shadingkorrigiert logarithm.

53. Apparatus according to claim 51, characterized in _/ that the computing device (17)

Image data of the receiving devices (16, 38) is divided into data for image inspection and data for color measurement.

54. The apparatus of claim 52 and 53, characterized in _/ that it is on the image data for an image inspection to difference image data, which are associated with pixel-wise stored parameter values and further processed as a weighted difference image data.

55. Apparatus according to claim 52 and 53, d a d u r c h g e k e n e z e i c h n e t that the computing device (17) the image data for the

Image inspection with respect to corresponding target data accumulates, normalizes and compares that a mean value filter is provided, which the

Differential image data accumulates pixel by pixel and that the computing device (17) with both the current and the accumulated image data with corresponding

Thresholds monitored.

55a Device according to Claim 53, so that the computing device (17) for determining the data for the color measurement has a plurality of adjacent measurement points for color measurement areas, e.g. B. per color zone, summarizes.

56. Apparatus according to claim 53, so that the computation device (17) determines the actual color locations for the color measurement areas.

57. Apparatus according to claim 56, characterized in _/ that the computing device (17) compares the calculated actual color locations with predetermined target color locations and regulates the color guidance in the individual printing units (2) at a color difference so that the color difference is minimized.

58. Apparatus according to claim 1, characterized in _/ that an operating device (19) is provided, which provides an interactive interface between the operator and the printing machine (1) and peripheral device (20, 21, 22) of the printing machine (1).

59. Apparatus according to claim 55a, characterized in _/ that the computing device (17) selects color measurement areas for all colors on the basis of the image data and determines their position coordinates and determines the measurement variables for the color assessment from the color measurement areas.

60. Device according to one or more of the preceding claims, characterized in _/ that the color measuring areas selected by the operator and the corresponding coordinates of these areas to the

Computing device (17) directed or. be determined by this.

61. Apparatus according to claim 56, characterized in _/ that it is in the Farbmeßbereichen to image areas.

62. Apparatus according to claim 56, characterized in _/ that it is in the measuring fields of a Farbmeßbereichen to Farbkontrollstrei ens.

63. Device according to claim 1, characterized in _/ that the computing device (17) from the deviations between measured and predetermined image data statistically occurring deviations from deviations which are caused by malfunctions of the printing press (1).

64. Apparatus according to claim 63, characterized in _/ that the computing device (17) the occurrence of malfunctions that affect print quality in the Farbmeßbereichen, automatically detects and prevents these measured variables are used for the color control.

65. The apparatus of claim 1 and 53, characterized in _/ that at least one register sensor (18, 22) is provided which detects the register error in the printed image, and that the computing device the measured values of the color measurement only releases when a correct register setting is carried out.