METHOD FOR OPERATING A FLEXOD PRINTING MACHINE, FLEXOD PRINTING MACHINE AND SYSTEM

Description

invention

[0001] The invention relates to a method having the features of the preamble of claim 1. The invention further relates to a flexographic printing machine, wherein the flexographic printing machine is operated for printing a printing substrate with flexographic printing ink according to a method according to the invention, having the features of the preamble of claim 10.

[0002] The invention further relates to a system comprising a flexographic printing machine according to the invention and a measuring device for measuring the dot density of the flexographic printing plate with the features of the preamble of claim 13. field of technology

[0003] The invention lies in the technical field of the graphic arts industry, and in particular in the area of ​​operating a flexographic printing press, i.e., a rotary printing press for printing with flexographic printing plates. In particular, the invention lies in the subfield of controlling or regulating the machine or its drives and / or actuators to prevent or reduce malfunctions. State of the art

[0004] In so-called flexographic printing, especially in industrial, web-processing flexographic printing, the requirement is to print cost-efficiently at high speeds using different flexographic printing forms from print job to print job, while keeping waste low and print quality high.

[0005] Printing cylinders, especially those with a preferably small size (in terms of the number / cost of flexo plates), are prone to disturbing vibrations.

[0006] Alternating print jobs with different printing forms or different print motifs can cause problems: the print motifs may have areas where a lot of printing is taking place, and areas where little is being printed, and areas where no or only insignificant printing is taking place ("channels"). Such channels can extend circumferentially within a printing form or—usually worse—axially. In prints with multiple printing forms, such channels can also be located between the spaced-apart printing forms. These channels (or the impacts they cause as they pass through the printing nip) can lead to vibrations in cylinders, printing units, or the press at certain production speeds.

[0007] In the prior art, so-called support strips were inserted into the channels or, when printing with multiple printing forms, these were arranged in such a way that no channels were created or that the number of channels was as small as possible and that they were uncritical with regard to disturbing vibrations (so-called "staging").

[0008] Flexographic printing plates can be measured before printing, e.g., in a measuring station. The subsequently published DE102020111341A1 discloses a device for measuring elevations on the surface of a rotating body and provides an improvement which, in particular, makes it possible to measure elevations on rotating bodies, such as flexographic printing dots on a flexographic printing plate, quickly and with high precision. The device disclosed in the document for measuring elevations on the surface of a rotating body designed as a cylinder, roller, sleeve, or plate of a printing press, e.g., a flexographic printing plate mounted on a sleeve, with a first motor for rotating the rotating body about a rotation axis and with a measuring device, is characterized in that the measuring device for contactless measurement comprises at least one radiation source and at least one area scan camera.

[0009] The other documents cited and described in the aforementioned document, DE3302798A1, DE102014215648A1, EP3251850, DE102006060464A1, WO2010146040A1, WO2008049510A1, and the "smartGPS ®<" system from Bobst described therein, constitute further prior art. The same applies to the "ARun" system from Allstein.

[0010] When operating web-processing rotary printing presses, disturbances that reduce print quality can occur, such as "bouncing" in flexographic printing. This is caused, for example, by vibrations of printing cylinders. The vibrations, in turn, can be caused by the print image or the arrangement of printing and non-printing areas on the flexographic printing plates.

[0011] A well-known, but unsatisfactory, measure to prevent bouncing is to alter the print image by adding additional—actually unwanted—printing or non-printing areas. Another well-known, but equally unsatisfactory—measure, which generates excessive waste—is to change the printing speed, since bouncing only occurs at certain printing speeds due to resonances. Such changes are usually made by a press operator.

[0012] DE102005012915A1 discloses: In a method for operating a machine with at least one rotating component at a desired target speed, the desired target speed is first checked for a critical target speed with regard to vibration resonances and, if necessary, identified as such. If the result is positive, the machine is deliberately not operated at this critical target speed in a stationary manner, but rather at a speed that is stationary at a certain speed interval from this critical target speed or that oscillates around this critical target speed. A vibration-detecting sensor, e.g., on a cylinder journal of the machine, can be used.

[0013] The subsequently published EP3838595A1 discloses a method for operating a rotary printing press, wherein disturbances in a rotating printing cylinder are detected and reduced by changing the printing speed. The disturbances are detected at an actuator of the printing cylinder.

[0014] EP2956304B 1 also discloses a solution to reduce bouncing: bevelled edges.

[0015] US2010011978A1 discloses a control of the speed of the printing cylinder depending on a topography, but a contact pressure is not determined depending on a profile or dot density of the printing form.

[0016] US10632737B2 discloses an apparatus for flexographic printing of a packaging material web with printing ink and an infeed module for a flexographic printing apparatus. The apparatus may comprise an ink chamber and an anilox roller rotating at least partially within the ink chamber for receiving and transferring printing ink from the ink chamber to a printing cylinder rotating in transfer contact with the anilox roller.

[0017] US2017165956A1 discloses a printing unit for a flexographic printing press, comprising - a plate cylinder carrying a cliché with a cliché reference field which has a plurality of reference field areas of different heights, - an impression cylinder whose distance from the plate cylinder can be varied under the control of a control unit for the purpose of pressing a printing substrate against the cliché, - an inking roller whose distance from the cliché can be varied under the control of the control unit for the purpose of inking it and whose surface can be wetted with ink from a connected ink reservoir, - a first sensor connected to the control unit for detecting a quality of a printed image of the cliché reference field on the printing substrate and - a second sensor connected to the control unit for detecting a quality of a negative image of the cliché reference field on the inking roller.

[0018] US5855739 discloses a wet-pressed paper web. The present invention also provides a method for producing a wet-pressed web.

[0019] Sleeves are usually only fitted with flexographic printing plates shortly before printing (assembly).

[0020] The connection between the press and prepress stages is significantly less pronounced in flexographic printing than, for example, in offset printing: JDF or XJDF as an interface between prepress and press is not established. Prepress data is therefore usually not available in the print shop. Often, prepress, especially the imaging of flexographic printing plates, even takes place in another company. Technical task

[0021] It is an object of the present invention to provide an improvement over the prior art which, in particular, enables cost-efficient and high-quality printing in industrial flexographic printing while avoiding disturbing vibrations. Inventive solution to the problem

[0022] This object is achieved according to the invention by a method according to claim 1, a flexographic printing machine according to claim 10, and a system according to claim 13. Advantageous and therefore preferred developments of the invention emerge from the subclaims as well as from the description and the drawings.

[0023] A method according to the invention for operating a flexographic printing machine with at least one flexographic printing form, with a printing cylinder carrying a sleeve for the flexographic printing form or with a flexographic printing cylinder for the flexographic printing form and with an impression cylinder which forms a printing nip with the printing cylinder or the flexographic printing cylinder, wherein a web of printing material is printed in the printing nip and a transport speed of the web is adjusted, is characterized in that the adjustment is carried out automatically either as a function of a dot density of the flexographic printing form, or data derived therefrom by calculation, or as a function of channels of the flexographic printing form, the printing cylinder or the flexographic printing cylinder, or data derived therefrom by calculation, wherein the dot density is a location-dependent density of printing elevations of the flexographic printing form,and wherein the dot density or the channels is / are measured contactlessly or wherein the dot density is determined computationally from prepress data for the production of the flexographic printing plate.,

[0024] A flexographic printing machine according to the invention, with at least one flexographic printing unit and with at least one flexographic printing form, comprising a printing cylinder carrying a sleeve for the flexographic printing form or a flexographic printing cylinder for the flexographic printing form, an impression cylinder which forms a printing nip with the printing cylinder or the flexographic printing cylinder, and an anilox roller, wherein the flexographic printing machine is operated for printing a printing substrate with flexographic printing ink according to one of the preceding methods, is characterized in that the flexographic printing machine comprises at least one drive motor for the rotational driving of the printing cylinder, the flexographic printing cylinder, the impression cylinder and / or an anilox roller and comprises a drive motor for conveying the web and that the drive motor is computationally controlled using the dot density, or data derived therefrom, or as a function of the channels, or data derived therefrom,is controlled or regulated in such a way that the transport speed of the web has a predetermined value or a predetermined range of values ​​or that the transport speed of the web excludes a predetermined value or a predetermined range of values.

[0025] A system according to the invention comprising a flexographic printing machine and a measuring device for measuring the dot density of the flexographic printing form is characterized in that the measuring device measures the dot density of the flexographic printing form or measures channels of the flexographic printing form, the printing cylinder or the flexographic printing cylinder and that the measuring device transmits the dot density or the channels, or data derived therefrom by computer technology, to the flexographic printing machine. Advantageous embodiments and effects of the invention

[0026] The invention advantageously enables cost-effective, high-quality printing in industrial flexographic printing while avoiding disruptive vibrations. The method according to the invention also advantageously enables further automation of printing.

[0027] The printed motifs can have areas where a lot of printing is taking place, and areas where little printing is taking place, and areas where no printing or only insignificant printing is taking place (hereinafter referred to as "channels"). Such channels can extend circumferentially within a printing form or—which is usually worse—axially. In prints with multiple printing forms, such channels can also be located between the spaced-apart printing forms. In particular, channels do not contain any printing elevations, meaning the dot density there is zero.

[0028] The term "channel" in this application is to be understood as follows: a print-free or essentially print-free location of a printed image of a flexographic printing plate or a print-free or essentially print-free location between two flexographic printing plates on a common sleeve; the location extends in the axial direction (relative to a rotational axis of a flexographic printing cylinder) and perpendicular thereto in the circumferential direction (relative to the circumferential direction of a flexographic printing cylinder); the location may extend in the axial direction over the entire length of a flexographic printing plate, but does not have to; the location extends in the axial direction at least with a length L > 200 mm or L > 300 mm or preferably L > 400 mm; the location extends in the circumferential direction at least with a width B > 3 mm or preferably > 5 mm; the location has no subsequent printing location in the axial direction with a length L > 10 mm or L > 20 mm or preferably L > 30 mm.

[0029] The term "channel pattern" in this application is to be understood as follows: The geometric pattern of at least two channels of a flexographic printing plate or at least two flexographic printing plates; in particular, the xy position of the channels and their length L and width B.

[0030] The invention is described and shown for a flexographic printing press or for flexographic printing plates (letterpress). Alternatively, the invention can be used for engraved printing plates or engraved sleeves (gravure printing). Instead of the term "flexographic," "gravure" or "flexo or gravure" can therefore be used in this application. Instead of "sleeve with flexographic printing plate," "sleeve with engraved form" or "engraved sleeve" or "laser-engraved sleeve" or "laser-engraved endless sleeve" or "endless printing plate" or "endless printing sleeve" can be used. Further developments of the invention

[0031] Preferred further developments of the invention (short: further developments) are described below.

[0032] A respective further development of the method according to the invention can be characterized by: that the dot density of the flexographic printing form is measured using means other than sensing rollers. that the dot density of the flexographic printing form is measured before printing. that the dot density of the flexographic printing form is measured before printing in a measuring device. that the measuring device comprises a receiving cylinder for the flexographic printing form or for a sleeve with the flexographic printing form. that the receiving cylinder rotates about an axis of rotation having an axial direction during measurement. that the measuring device is operated outside the flexographic printing press. that the measurement is carried out using a topographer. that a camera is used during measurement. that an area scan camera is used during measurement. that a line scan camera is used during measurement. that at least one CIS sensor is used in the camera. that a stationary camera is used during measurement. that the camera is moved perpendicular to the axial direction before measurement.that the camera is moved in the axial direction during measurement. that a radiation source, in particular a light source, is used when measuring with the camera. that the entire printed image of a flexographic printing form or of the printing cylinder is recorded during measurement. that at least one flexographic printing form or at least two flexographic printing forms are mounted and recorded on a sleeve during measurement. that the entire sleeve, i.e. its outer surface with mounted flexographic printing forms, is recorded during measurement. that light from a light source reaches elevations on the flexographic printing form and from there to the camera. that at least one mirror is used when measuring with the camera. that the mirror is arranged so that it can move. that the mirror is moved perpendicular to the axial direction before measuring. that the mirror is moved in the axial direction during measuring.that during measurement light travels from a light source to elevations on the flexographic printing form and from there via the mirror back to the camera. that a laser and a triangulation measuring method are used for measurement. that the dot density is determined computationally from prepress data for producing the flexographic printing form. that setting values ​​are calculated. that the setting values ​​are transmitted to a control system of a motor for the rotary drive of the printing cylinder and / or the impression cylinder and / or an anilox roller and / or to a control system of a motor for conveying the web. that the calculation is carried out as a function of a dot density of the flexographic printing form, i.e. a location-dependent density of printing elevations on the flexographic printing form, - or data derived from this computationally - or as a function of channels of the flexographic printing form or the printing cylinder - or data derived from this computationally.that different speeds of the printing cylinder are used when calculating the setting values. that different surface speeds of the flexographic printing plate at different speeds are calculated when calculating the setting values. that different axial thicknesses of flexographic printing plates and / or sleeves are used when calculating the surface speeds. that different frequencies for channel impacts are calculated at different surface speeds when calculating the setting values. that at least one frequency for a channel impact or a channel impact pattern of several channels of a flexographic printing plate or several flexographic printing plates at different surface speeds is calculated when calculating the setting values.that measured and / or specified resonance frequencies of the printing cylinder and / or the impression cylinder and / or of components of the flexographic printing press and / or of printing units of the flexographic printing press and / or of the flexographic printing press are used or excluded when calculating the setting values. that the specified resonance frequencies are digitally stored and retrieved. that the specified resonance frequencies are determined beforehand by sensors. that the sensory determination is carried out using at least one sensor on an actuator for a setting pressure between the flexographic printing cylinder and the impression cylinder. that cylinder speeds critical for resonances are determined. that when operating the flexographic printing press with one or more previously measured flexographic printing formes orthat when operating a flexographic printing press with multiple printing units, each with one or more previously measured flexographic printing units or flexographic printing units, such speeds of the printing cylinders of the printing units are avoided or, when changing the speed, exceeded (selecting a higher speed than the critical speed) or undershot (selecting a lower speed than the critical speed) which, as a result of at least one channel strike or channel strike pattern in one or more channels, generate resonant vibrations that detract from the print quality.that when avoiding the speeds, a speed difference from a resonant speed of at least 3 m / min or at least 4 m / min is maintained. that a computer, i.e. a digital computer, is used in the calculation. that the dot density or the data derived from it is or are transmitted to the computer. that the flexographic printing press comprises an anilox roller for inking the flexographic printing forme. that a calculated target value of the setting value is compared with a recorded actual value of the setting value during fault-free printing and that a deviation of the target value from the actual value is calculated from the comparison and that a correction value is calculated. that different correction values ​​are calculated and stored when printing with different flexographic printing forms from a number of flexographic printing forms.that an AI runs computational learning steps with the stored correction values, and that before printing, the AI ​​determines a correction value for the flexographic printing form using another flexographic printing form that differs from the number of flexographic printing forms, and that this correction value is used during printing. that cylinder speeds critical for resonances, i.e., those to be avoided, are determined as target values, and that cylinder speeds at which resonances actually occur during machine operation are measured – preferably automatically – as actual values ​​(e.g., using a method as disclosed in the subsequently published EP3838595A1), and that both values ​​are compared computationally. From a plurality of such comparisons and any deviations of the actual values ​​from the target values ​​determined in the process, a computer or an AI can learn and correct or "better predict" future target values ​​accordingly.This allows for even better prevention of disruptive resonances. Alternatively, a so-called look-up table can be used, which preferably contains information on changes in cylinder speeds that are critical for resonances and should therefore be avoided, depending on changes to the machine, such as changing sleeves or sleeve diameters / circumferences.

[0033] A respective further development of the flexographic printing machine according to the invention can be characterized by: that the drive motor is controlled or excited by computer using the dot density or data derived therefrom or as a function of channels of the flexographic printing forme or printing cylinder - or data derived therefrom - in such a way that the transport speed of the web has a predetermined value or a predetermined range of values ​​or that the transport speed of the web excludes a predetermined value or a predetermined range of values. that when the flexographic printing press is in operation, paper, cardboard, board, which may also be coated, film or composite material is printed. that the flexographic printing forme has at least one channel. that the sleeve carries at least two flexographic printing forms with the same or different print motifs. that the two flexographic printing forms are mounted on the sleeve one after the other in the circumferential direction or one after the other in the axial direction.that at least one flexographic printing plate has at least one channel and / or that a channel is formed between the flexographic printing plates.

[0034] A respective further development of the system according to the invention can be characterized by: that the measuring device is part of a measuring station which is arranged separately from the flexographic printing press. that the flexographic printing form and / or the sleeve is marked with a machine-readable ID. that the ID is designed as a unique identifier for the sleeve. that the identifier comprises a plurality of characters, in particular numbers and / or letters. that the ID is marked as a one-dimensional code, in particular a barcode, or as a two-dimensional code, in particular a QR code, or as an RFID chip or NFC chip. that the measuring device transmits the dot density or data derived therefrom or the channels of the flexographic printing form or the printing cylinder - or data derived therefrom by computer - together with the ID directly to the flexographic printing press.that the measuring device transmits the dot density or data derived therefrom or the channels of the flexographic printing form or the printing cylinder - or data derived therefrom computationally - together with the ID indirectly to the flexographic printing press by temporarily storing the dot density or the data derived therefrom and retrieving it from the flexographic printing press for printing with the flexographic printing form and / or the sleeve. that the derived data comprise at least one channel pattern or a frequency corresponding to a channel pattern. that the temporary storage takes place on a central storage or a cloud storage. .

[0035] A respective further development of the flexographic printing plate or sleeve for a flexographic printing plate according to the invention can be characterized by: that the marking with the machine-readable ID is carried out using a marking agent which is different from an RFID chip.

[0036] The features and combinations of features disclosed in the above sections Technical Field, Invention and Further Developments as well as in the following section Exemplary Embodiments represent - in any combination with one another - further advantageous developments of the invention. Embodiments of the invention and figures

[0037] The Figures 1 to 5 show a flexographic printing machine, a measuring station with a measuring device (various designs) and a measuring method.

[0038] The Figure 6 shows the captured image of a sleeve with two flexographic printing plates as an example.

[0039] Corresponding features are provided with the same reference symbols in the figures. Some recurring reference symbols have been omitted for clarity.

[0040] Figure 1shows a cross-section of a rotatable support cylinder 1 of a measuring station 2, a sleeve 3 mounted on the support cylinder and a printing plate 5 (flexographic printing form) mounted on the sleeve, preferably fastened to the sleeve by means of an adhesive tape 4 (or alternatively by means of an adhesive coating of the sleeve) (so-called "mounting"), to be measured at least with regard to its topography as a rotational body 6. Alternatively, a self-adhesive sleeve can be used.

[0041] A motor 7 can be provided in the measuring station to rotate the carrier cylinder during measurement. The measuring station can be part of a so-called "mounter" (in which printing plates are mounted on carrier sleeves) or can be provided separately from a mounter. The measuring station can be provided separately from a printing press 8 (flexographic printing press) – with at least one printing unit 9 (flexographic printing unit) for the printing plate 5 and a dryer 10 for printing and drying a preferably web-shaped printing substrate 11 (alternatively: sheet-shaped). The printing plate is preferably a flexographic printing forme with a diameter of 106 mm to 340 mm. The dryer is preferably a hot-air dryer and / or a UV dryer and / or an electron beam dryer and / or an IR dryer. The sleeve can be slid laterally onto the carrier cylinder.The support cylinder can have openings in its outer surface through which compressed air can be expelled to expand the sleeve and create an air cushion when it is pushed on. After measuring, the sleeve with the printing plate can be removed from the measuring device and pushed onto a printing cylinder of the printing unit in the printing press. A hydraulic clamping system can also be used as an alternative to the pneumatic clamping system.

[0042] Calibration of the measuring station 2 can be performed using measuring rings 12 on the support cylinder 1. Alternatively, a measuring sleeve or the support cylinder itself can be used for calibration.

[0043] Figure 1also shows a digital computer and / or digital memory 39, 39b, 123, 317, 401 and / or 403. The measuring device can generate data and transmit it to the computer / memory. The data can be measured values ​​or data derived therefrom, which are generated when measuring the sleeve 3 and / or the flexographic printing plate(s) 5. The computer / memory can be part of the measuring device 2 or part of the flexographic printing machine 8; or can be provided separately, e.g., as a central computer / memory (e.g., of a printing company) or cloud-based. The computer / memory can transmit data to the flexographic printing machine, e.g., the measured values ​​or the data derived therefrom or data further derived therefrom. The further derived data can be generated by a computer-implemented algorithm and / or an AI (artificial intelligence; software- and / or hardware-based, self-learning and machine-learning system).The computer / memory unit can receive data from multiple measuring stations and transmit data to or from multiple flexographic printing presses. The system consisting of flexographic printing press(es), measuring station(s), and computer / memory unit allows for a high level of automation during printing, including autonomous printing. This advantageously prevents operator error-prone data entries and / or changes.

[0044] The following figures show preferred embodiments of devices for the contactless measurement of elevations 13 of the surface 14 of a rotation body 6 designed as a flexographic printing form of the printing press 8 (cf. Figure 2C). The elevations can be flexographic printing dots (in the screen) or flexographic printing areas (in the solid area) of a flexographic printing plate. The following exemplary embodiments describe the measurement of a printing plate 5 as an example. Measuring the printing plate enables automatic presetting of the respective optimal working pressure between the cylinders involved in the printing process, e.g., screen cylinder 15, printing cylinder 16 with printing plate 5, and impression cylinder 17.

[0045] The Figures 2A to 2C show a preferred embodiment of the device for measuring the topography of a printing plate 5; Figure 2A in cross-section, Figure 2B in plan view and Figure 2C an enlarged section of Figure 2A . According to this embodiment, the topography is preferably recorded using multiple devices 18 as part of a 3D radius determination with an optional reference line.

[0046] In this and the following embodiments, "2D" means that a section of the printing plate 5 (e.g., annular height profile) is scanned and "3D" means that the entire printing plate 5 (e.g., cylindrical height profile composed of annular height profiles) is scanned.

[0047] The device comprises a plurality of radiation sources 19, in particular light sources 19, preferably LED light sources, at least one reflector 20, e.g., a mirror, and at least one light receiver 21, preferably an area scan camera and particularly preferably a high-speed camera. In the following, light sources are assumed to be the radiation sources by way of example, i.e., visible light is emitted. Alternatively, the radiation source can emit other electromagnetic radiation, e.g., infrared. The light sources are preferably arranged in a row perpendicular to the rotation axis 22 of the support cylinder 1 and generate a light curtain 23, whereby the support cylinder 1 with sleeve 3 and pressure plate 5, i.e., the contour, generates a shadow 24. The reflected and then received light 25, i.e., essentially the emitted light 23 without the light 24 shadowed by the topography 13, carries information about the topography 13 to be measured.The reflector 20 can be designed as a reflective foil. The information can, for example, be information from the flexographic form about printing or non-printing areas or their height, or information from the flexographic form about its local dot density.

[0048] The light source 19 is planar (area camera). The light source preferably emits visible light. The light sources 19 and receivers 21 preferably cover the working width 26, i.e. the extent of the printing plate 5 in the direction of its axis 22 (e.g. 1650 mm). Preferably, n light sources 19 and receivers 21 can be provided, where e.g. 2>n>69. When using smaller cameras, a higher upper limit than 69 may be necessary. If the entire working width 26 is covered, the printing plate 5 can be measured during one rotation of the carrier cylinder 1. Otherwise, the light sources and light receivers must be moved or clocked in the axial direction 27 along the printing plate.

[0049] Inexpensive but fast-acting cameras 21, such as black-and-white cameras, are preferred. These cameras can capture individual images or a film during the rotation of the printing plate 5.

[0050] The device comprising light sources 19, reflector 20, and light receiver 21 can preferably be moved in a direction 28 perpendicular to the axis 22 of the support cylinder 1 in order to direct the generated light strip 23 onto the topography 13 to be measured. A motor 29 can be provided for this purpose. It can also be provided to design the reflector in a stationary manner and move only the light source and / or the light receiver, e.g., by motorization.

[0051] Contrary to the illustration, the topography 13 is preferably measured in a vertical direction (e.g. camera "down" and reflector "up") and not in a horizontal direction, since in this case a possible deflection of the support cylinder 1 and the reference object 30 can be disregarded. With this preferred solution, one must consider the Figure 2a Imagine rotated 90° clockwise.

[0052] A linear object 30, preferably a taut thread 30 or a taut string 30, e.g. a metal wire or a carbon fiber or a knife (or a knife-like object or an object with a cutting edge) or a beam, is provided as an optional reference object 30, which creates a reference line 31 for the plurality of light receivers 21. The linear object preferably extends parallel to the axis of the support cylinder 1 and is arranged at a short distance 32, e.g. 2 mm to 10 mm (maximum up to 20 mm), from its outer surface 33 or the printing plate 5 arranged thereon. The received light 25 also contains evaluable information about the reference object 30, e.g. its location and / or distance from the surface 14 of the printing plate 5 (preferably etched and therefore deeper than the elevations 13). By means of the reference line, the radial distance R of the topography 13 orthe contour or the contour elevations to the reference object 30, preferably using digital image processing. The distance of the reference object 30 from the axis 22 of the carrier cylinder 1 is known from the arrangement and / or motorized adjustment of the reference object 30 (optionally together with the light source 19 and light receiver 21 and, if applicable, the reflector 20). The radial distance of the contour elevations, i.e. the radius R of the pressure points, can thus be determined mathematically. By using the reference object 30 and thus the presence of a shadow caused by it or a reference line 31 corresponding to the shadow (in the recorded image or from the received light) of each camera 21, an exact, e.g. pixel-precise alignment of the cameras to one another is not absolutely necessary. Furthermore, the reference object 30 can be used to calibrate the measuring system.

[0053] The reference object 30 can be coupled to the light source 19 and / or the motor 29 for movement or adjustment in direction 28. Alternatively, the reference object can have its own motor 29b for movement / adjustment.

[0054] For initial referencing of the device, a measurement is preferably performed with the ("empty") carrier cylinder or a measuring sleeve mounted on it (measuring the distance between the reference object and the surface from the drive side to the operating side). AS and BS are abbreviations for the designations drive side and operating side of a machine, e.g., a printing press, in which the sleeve is to be used. Both these designations and their abbreviations are common in the graphic arts industry and are therefore familiar to the expert.

[0055] To further initialize the device before the measurement process, the area scan camera 21 is preferably first moved in direction 28 toward the support cylinder 1. The movement is preferably stopped as soon as the camera detects the first elevation. The reference object 30 is then preferably also moved in direction 28 to a predetermined distance, e.g., 2 mm, from the support cylinder 1.

[0056] Light source 19 and light receiver 21 can alternatively be arranged on opposite sides of the carrier cylinder 1; in this case, the reflector 20 can be omitted.

[0057] Preferably, the light source 19, the reflector 20 (if present according to the embodiment), the light receiver 21 and the optional reference object 30 form a movable (perpendicular to the axis 22 of the carrier cylinder), in particular a motor-adjustable or movable unit 34.

[0058] During the measurement, the support cylinder 1 rotates with the printing plate 5 located thereon, so that preferably all elevations 13 in the circumferential direction 35 can be detected. From this, depending on the angular position of the support cylinder 1, a topography image and the radius R of individual elevations 13, e.g., flexographic printing dots, relative to the axis 22 or the diameter D (measured between opposing elevations) can be determined.

[0059] In the enlarged view of the Figure 2C A section of the topography 13 of the printing plate 5 is shown, and the shading 24 of the topography and the shading 36 of the reference object 30 are visible. The topography elevations 13 can range from 2 µm to 20 mm.

[0060] Furthermore, a sensor 37 can be provided which detects the sleeve 3 and / or the pressure plate 5 using an identification feature 38 (cf. Figure 2B). This feature can be, for example, a barcode, a 2D code (e.g., QR code or data matrix code), an RFID chip, or an NFC chip.

[0061] The signals and / or data generated by the light receivers 21, which include information about the topography 13 of the measured surface 14 and about the reference object 30, are transmitted to a computer 39, preferably via a cable or radio link, where they are further processed. The computer is connected to the printing press 8. The computer 39 evaluates the information.

[0062] The reference object 30 can be brought into the detection range of the light receiver 21 before the measurement in order to calibrate the light receiver. The light receiver 21 detects the reference object and transmits the generated calibration signals to the computer 39. The calibration data is stored in the digital memory 40 of the computer 39.

[0063] This makes it possible to store a virtual reference object in the computer 39. Subsequently, the reference object 30 is removed from the detection range of the light receiver 21, and the topography 39 of the surface 14 being measured is further processed together with the virtual reference object.

[0064] The result of the evaluation is stored in a digital memory 40 of the computer, in a memory 40 of the printing press, or in a cloud-based storage. The results are preferably stored associated with the respective identification feature 38. During later use of the printing plate 5 (or the sleeve / flexographic printing forme) mounted on a sleeve in the printing press 8, the identification feature 38 of the printing plate 5 or of the flexographic printing forme (or the sleeve) can be read in again. The values ​​stored for the identification feature 38 can then be retrieved, e.g., for the purpose of presetting. For example, it can be provided that the printing press receives the data required for a print job from the cloud-based storage.

[0065] The result of the evaluation can preferably comprise up to four values: The operationally required printing feeds of the printing cylinder 16, i.e. the cylinder carrying the measured printing plate 5 on the two sides 41 or AS (drive side) and 42 or BS (operating side) against the impression cylinder 17 or printing material transport cylinder 17 and the operationally required printing feeds of an anilox roller 15 inking the measured printing plate 5 on the two sides 41 or AS (drive side) and 42 or BS (operating side) against the printing cylinder 16.

[0066] Furthermore, a device 43 for detecting the dot density, e.g., via optical scanning, can be provided, preferably a CIS scanner bar (Contact Image Sensor), a line scan camera, or a laser triangulation device. Alternatively, the device 43 can be a pivotable or movable mirror such that it can be used together with the light sources 19, 21 to measure the dot density. The device is preferably connected to a device for image processing and / or image evaluation, which is preferably the computer 39—or the computer 39 with appropriate programming—or which can be another computer 39b.

[0067] A CIS scanner bar can be arranged parallel to the cylinder's axis. It preferably comprises LEDs for illumination and sensors for image acquisition (similar to a scanner bar in a standard copier). The bar is preferably arranged at a distance of 1 to 2 cm from the surface or is positioned at this distance. The cylinder with the surface to be measured, e.g., the printing plate, rotates beneath the bar, which creates an image of the surface and makes it available for image analysis for dot density evaluation. The data obtained from recording the dot density can, for example, also be used to computationally select or recommend an optimal anilox roller for printing with the detected printing form from a pool of available anilox rollers.

[0068] The Figures 3A and 3B show a preferred embodiment of the device for measuring the topography of a printing plate 5; Figure 3Ain cross-section and Figure 3B in plan view. According to this embodiment, the topography is preferably recorded with a laser micrometer 44 as part of a 2D diameter determination.

[0069] The device comprises a light source 19, preferably a line-shaped LED light source 19 or a line-shaped laser 19, and a light receiver 21, preferably a line-scan camera 21. The laser and light receiver together form a laser micrometer 44. The light source 19 generates a light curtain 23, and the support cylinder 1 with sleeve 3 and pressure plate 5 generates a shadow 24. The line lengths of the light source 19 and the light receiver 21 are preferably greater than the diameter D of the support cylinder including sleeve and pressure plate in order to enable the topography without moving the device 44 perpendicular to the axis 22 of the support cylinder. In other words, the cross-section of the support cylinder is located entirely within the light curtain.

[0070] The device 44 comprising the light source 19 and the light receiver 21 can be moved parallel to the axis 22 of the support cylinder (in direction 27) to cover the entire working width 26. A motor 45 may be provided for this purpose.

[0071] A sensor 37 can be provided which detects the sleeve 3 and / or the pressure plate 5 using an identification feature 38 (cf. Figure 2B ).

[0072] The signals and / or data generated by the light receivers 21 are transmitted to a computer 39, preferably via a cable or radio link, where they are further processed. The computer is connected to the printing press 8.

[0073] Light source 19 and light receiver 21 can alternatively be arranged on the same side of the carrier cylinder 1; in this case, a reflector 20 is arranged opposite, similar to that shown in the Figures 2A to 2C arranged.

[0074] According to an alternative embodiment, the topography is preferably recorded with a laser micrometer 44 as part of a 2D diameter determination, whereby not just a single measuring line 46, but a wider (shown in dashed lines) measuring strip 47 consisting of several (shown in dashed lines) measuring lines 48 is recorded. In this exemplary embodiment, the light source 19 and the light receiver 21 are preferably planar and not merely linear. The light source 19 can comprise several light lines 48, each approximately 0.1 mm wide and approximately 5 mm apart. In this example, the camera is preferably designed as an area scan camera.

[0075] The Figures 4A and 4B show a preferred embodiment of the device for measuring the topography of a printing plate 5; Figure 4A in cross-section and Figure 4Bin plan view. According to this embodiment, the topography is preferably measured with a laser micrometer as part of a 2D radius determination.

[0076] The device comprises a light source 19, preferably an LED light source 19, and a light receiver 21, preferably a line-shaped LED light source 21 or a line-shaped laser 21. The light source 19 generates a light curtain 23, and the carrier cylinder 1 with sleeve 3 and printing plate 5 generates a shadow 24.

[0077] The device comprising light source 19 and light receiver 21 can preferably be moved in a direction 28 perpendicular to the axis 22 of the support cylinder 1 in order to direct the light curtain 23 onto the topography 13 to be measured. A motor 29 may be provided for this purpose. If the light curtain 23 is wide enough and therefore covers the measuring range, the motor 29 can be omitted.

[0078] The signals and / or data generated by the light receivers 21 are transmitted to a computer 39, preferably via a cable or radio link, and further processed there. The computer is connected to the printing press 8. Light source 19 and light receiver 21 can alternatively be arranged on the same side of the carrier cylinder; in this case, a reflector 20 is arranged opposite, similar to the Figures 2A to 2C arranged.

[0079] According to an alternative embodiment, the topography 13 is preferably measured with a laser micrometer 44 as part of a 3D radius determination, whereby not just one measurement line 46, but a wider (shown in dashed lines) measurement strip 47, i.e., several measurement lines 48, are measured simultaneously. In this embodiment, the light source 19 and light receiver 21 are planar and not merely linear.

[0080] According to a further alternative embodiment, the topography 13 is preferably measured with a laser micrometer 44 as part of a 3D radius determination, wherein the device comprising the light source 19 and the light receiver 21 can preferably be moved in a direction 28 perpendicular to the axis of the support cylinder 1 in order to direct the light curtain 23 onto the topography 13 to be measured. A motor 29 (shown in dashed lines) can be provided for this purpose.

[0081] According to an alternative embodiment, the topography 13 is preferably measured with a laser micrometer 44 as part of a 3D radius determination, wherein the last two alternative embodiments are combined.

[0082] Figure 5shows an exemplary and greatly enlarged topography measurement result of a printing plate 5 (flexographic printing form) with two printing areas 50 and two non-printing areas 51. The radial measurement results for 360° at an axial location (relative to the axis of the carrier cylinder) are shown. The non-printing areas can, for example, have been created by etching and thus have a smaller radius than the printing areas.

[0083] The illustration also shows an enveloping radius 52 or an envelope 52 of those points of the pressure plate 5 with the largest radius, ie the highest elevations of the topography 13 at the axial location.

[0084] Dot 53 on printing plate 5 is a printing dot, as during printing operation, with a normally set pressure or print feed between printing plate 5 and substrate 11 or transport cylinder 17, it would have sufficient contact with the substrate and the ink-transferring anilox roller. Normally set pressure produces a so-called kiss print, in which the printing plate just touches the substrate and the flexographic printing dots are not significantly squeezed.

[0085] Dot 54 is a dot which would just print in printing operation with the pressure set normally, as it would just have contact with the printing material.

[0086] The two dots 55 are dots that would not print because, during printing, with the pressure set normally, they would have no contact with the printing substrate or the anilox roller.

[0087] A computer program runs on the computer 39 which, in the printing area 50, calculates the radially lowest point 56 and its radial distance 57 from the envelope 52 using calculations, e.g. using digital image processing. This calculation is carried out at regular intervals in the axial direction, e.g. from AS to BS at all measuring points, and the respective maximum of the lowest points (i.e. the maximum lowest value) from AS to the middle and from the middle to BS is determined. The two maxima or the feed values ​​or setting values ​​determined from them can be selected, for example, as the respective feed / setting on AS and BS during printing, i.e. the cylinder distance between the cylinders involved in printing is reduced by the feed on AS and BS. For this purpose, a motor-driven threaded spindle can be used from AS and on BS. Below is a concrete numerical example:

[0088] On one side, the distance deltaR = 65µm, and on the other, the distance deltaR = 55µm. To print all dots 53 to 55 on the printing plate, a feed of 65µm is required.

[0089] In all illustrated embodiments and their alternatives, the manufacturing-related and / or operational (wear-related) concentricity of the sleeve 3 can also be measured. Based on the measurement and evaluation results, this can be taken into account during printing to improve the quality of the printed products. If a specified concentricity tolerance is exceeded, a warning can be issued. Measurements can be performed on smooth and porous sleeves.

[0090] Instead of light sources 19 or light emitters 19 (which emit visible light), radar emitters 19 (with correspondingly adapted receivers) can also be used within the scope of the invention.

[0091] In all of the embodiments shown and the alternatives mentioned, parameters for dynamic print feed can also be determined and transferred to the printing press. For example, a known (e.g., previously measured) delayed expansion of the deformable and / or compressible printing dots 53 to 55 made of polymer material can be taken into account. Or a printing plate hardness determined beforehand using a durometer can be used. This expansion can depend, in particular, on the printing speed prevailing during operation, or this printing speed dependency can be taken into account. For example, a higher print feed can be selected at higher printing speeds.

[0092] The printing area of ​​the printing plate 5 or the dot density, ie the variable density of the printing dots on the printing plate 5, can also be taken into account (alternatively or in addition to the printing speed): For example, with higher dot densities a higher print setting can be selected and / or the dot density can be used when setting the dynamic print setting.

[0093] To determine the local point density, the received light 25, i.e., essentially the emitted light 23 without the light 24 shadowed by the topography 13, can be used. It carries information about the topography 13 to be measured and / or its surface point density and / or elevations.

[0094] For this purpose, a device 43 for detecting or measuring the dot density, i.e., its local values, on the printing form, e.g., flexographic printing form, can also be provided, preferably a CIS scanner bar or a line scan camera. For example, it can be provided, based on the data obtained / calculated from the dot density determination, to provide default values ​​for different printing adjustments on the AS (drive side of the printing press) and BS (operating side of the printing press).

[0095] Knowing the dot density of the printing plate 5 and / or the inking anilox roller 15 and / or anilox sleeve 15, the expected ink consumption when printing with the printing plate on a given substrate 11 can be calculated. From the ink consumption, the required drying capacity of the dryers 10 for drying the ink on the substrate can be calculated. Based on the calculated, expected ink consumption, the ink supply to be provided can also be calculated.

[0096] In all embodiments shown and their alternatives mentioned, a so-called channel runout pattern can also be taken into account. A channel runout pattern is a disturbance that occurs periodically during the operational rotation of the printing plate 5, which is caused by a gap or channel in the print image that is the width of the page or at least disturbingly wide, i.e., a disturbingly large area without print dots, or another axial channel - usually extending in the axial direction. The print quality can be impaired by such channels or their channel runout patterns, since the cylinders involved in printing approach and repel each other rhythmically due to the kissprint adjustment in the area of ​​the channel that recurs during rotation. In the worst case, this can lead to unwanted density fluctuations or even print dropouts. An existing channel runout pattern can preferably be measured using a CIS measuring device 43 (e.g.The measured channel runout pattern can be used to predict the speeds or rotational frequencies of a printing press at which oscillations or vibrations would occur. These speeds or rotational frequencies are then not used during production and are overrun, for example, when the machine is started up.

[0097] Each printing plate 5 can exhibit an individual channel impact pattern. Channels in the printing plate can negatively impact the printing result or even lead to print dropouts. To mitigate or even eliminate channel impact, the printing plate is examined for channels in the unwinding direction. Given known resonance frequencies of the printing unit 9, production speeds can be calculated that are particularly unfavorable for a given printing plate. These printing speeds should be avoided (so-called "no-go speed").

[0098] In all of the embodiments shown and the alternatives mentioned, register marks (or multiple register marks, e.g. wedges, double wedges, dots or crosshairs) on the printing form can also be detected, e.g. using the camera 21 or 43 and a downstream digital image processing system, and their position can be measured, stored and kept ready. This enables automatic adjustment of register controllers or their register sensors to the register marks or to axial positions. Errors caused by the otherwise usual manual adjustment of the sensors can thus be advantageously prevented. Alternatively, patterns can be detected and used to configure a register controller. It can also be provided for the automatic positioning of a motor-driven register sensor, in particular in the axial direction.It can also be provided to align a predetermined zero point of the angular position of a printing cylinder and / or a sleeve arranged thereon with an angular value of the actual location of a print image (e.g., one applied by hand), particularly in the circumferential direction (or of the cylinder / sleeve). From this alignment, an optimal starting value for the angular position of the cylinder / sleeve can be obtained. In this way, print production can be started with reduced register deviation. The same applies to the lateral direction (or of the cylinder / sleeve).

[0099] In all illustrated embodiments and their alternatives, the power of the dryer 10 of the printing press 8 can also be controlled or regulated. For example, LED dryer segments can be switched off in areas where no printing ink has been transferred to the substrate, thereby enabling advantageous energy savings and extending the lifespan of the LEDs.

[0100] Further advantageously, the power of the dryer 10 or the power of individual segments of the dryer can be reduced for printing areas on the printing plate with low dot density. This can save energy and / or extend the service life of the dryer or individual segments. The shutdown or reduction can take place in specific areas and in a direction parallel and / or transverse to the axial direction of a printing plate or to the lateral direction of the printing substrate to be processed with it. For example, segments or modules of a dryer can be switched off in areas that correspond to gaps between printing plates (e.g., printing plates arranged at a distance from one another, in particular those glued on by hand).

[0101] In all embodiments shown and their mentioned alternatives, the respective location (on the printing plate 5) of measuring fields for print inspection systems can also be recorded and made available for further use, e.g. the location setting of the print inspection systems.

[0102] In all illustrated embodiments and their alternatives, an inline color measurement system can also be positioned. To determine the location and thus the position of the inline color measurement, image and / or pattern recognition is performed, which is used to determine the axial position for the measurement system. To allow for a free spot for calibration on the printing substrate, free printing locations can be communicated to the inline color measurement system.

[0103] The following is an example of an overall process that can be carried out using the device in a suitable embodiment. Measurement process:

[0104] Step 1: Sleeve 3 with or without pressure plate 5 is pushed onto the air-pressurized carrier cylinder 1 of the measuring station 2 via the air cushion and locked in place. Step 2: The sleeve is identified with a unique character string 38. This can be done using a barcode, 2D code (e.g. QR code or data matrix code), RFID code, or NFC. Step 3: Camera 21 and optionally the reference object 30 are positioned according to the diameter (of the sleeve with or without pressure plate). Step 4: Determination of the topography 13 of the pressure plate with a reference point to axis 6 or the axis center of the carrier cylinder 22, i.e. the radii of the elevations / pressure points 53 to 55. The light source 19 and the camera 21 of the measuring device 18 move axially if necessary, and the carrier cylinder rotates (its angular position is known via an encoder).Step 5: Performing an area scan to detect dot densities, free printing spots, printing areas, register marks and / or measuring fields for inline color measurement. Step 6: Application of a topography algorithm running on a computer 39 and evaluation of the areas via the area scan with detection of channel runout patterns and with register mark field setup or inline color measurement. Step 7: Optional determination of the plate hardness (in Shore units). Step 8: Application of a dust detector and / or a hair detector. Step 9: Saving the measurement results in a digital memory 40. Step 10: Display of the measurement results with information on dust / hairs or trapped air bubbles and / or display of limit values ​​such as concentricity, eccentricity and / or crowning. Step 11: Possible repetition of the measurement or removal of the core in order to measure another core. . Setup process:

[0105] Step 1: Sleeve 3 with printing plate 5 is pushed onto the pressurized printing cylinder 16 of the printing press 8 via the air cushion and locked into place. Step 2: The sleeve is identified with its unique character string 38 by the respective printing unit 9 or a sensor there. This can be done via barcode, 2D code (e.g., QR code or data matrix code), RFID code, or NFC. Step 3: The printing unit or printing press retrieves the stored data for the corresponding identified sleeve. Setting process:

[0106] Step 1: Adjustment of the so-called "kiss print" (setting the pressure or working pressure) for printing cylinder 16 and anilox cylinder 15, e.g., based on topography, concentricity, and substrate data for an optimal print dot. The diameter and radius are determined. The diameter and radius are known from measurements. Step 2: Calculation of the pre-register based on register mark data on the printing plate or sleeve reference point. Step 3: Adjustment of the dynamic print adjustment based on the determined dot density values, printed area, speed, and optionally the printing substrate. Optional consideration of plate hardness (in Shore units). Step 3: Adjustment of the optimal material web speed, e.g., based on the calculation of the determined resonance frequencies of the printing unit to the printing plate using channel runout pattern recognition.Step 5: Setting the optimal drying performance (UV or hot air) based on dot density values ​​and printed area, as well as anilox cylinder data (cupping volume, etc.), optionally dynamically adjusted to the web speed. Step 6: Calculating ink consumption based on dot density values ​​and printed area, as well as anilox cylinder data (cupping volume, etc.). Step 7: Reducing or switching off LED UV dryer sections in places where there is a low dot density on the printing plate or where no drying is required, in order to save energy and increase the service life of the LED lamps. Step 8: Fully automatic adjustment of the register controller based on the acquired register mark data, e.g. mark configuration and automatic, axial positioning of the register sensor. Step 9: Setting the measuring position for spectral inline measurement and print inspection of the printed colors, information about the location and / orMeasuring position. .

[0107] Figure 6 shows a captured image 410 of a sleeve 300 and, by way of example, two flexographic printing plates 301 and 302. The image is preferably captured or generated by a camera 400, in particular in a measuring station 2. The image can be transmitted to a computer 401. This can be the computer 39 from Figure 2a The image can be subjected to computer-based image processing. Information or data can be obtained in the process. This data can be stored in a digital memory 317 for an ID or identifier 316 of the sleeve and made available to the flexographic printing press when the sleeve is used, citing the ID.

[0108] Shown as an example is a detected area 303 with high dot density and a detected area 304 with low dot density. The areas can be detected and separated using image processing technology, and preferably color-coded. From the knowledge of the local dot densities of the entire flexographic printing form 301 (and the additional flexographic printing form 302), a preset value for the so-called pressure adjustment can be calculated, i.e., for setting the contact pressure between the flexographic printing cylinder and impression cylinder (and / or anilox roller) when using the sleeve.

[0109] Also shown as an example is a detected channel 305. In the area of ​​channel 305, there are no (or essentially no) printing elevations of the flexographic printing plate 301, i.e., the dot density in this area is zero. Channel 305 extends primarily in the axial y-direction and, due to its y-length (and x-width), is critical with regard to possible channel impacts when passing through the printing gap and thus with regard to possible disruptive oscillations or vibrations during operation of the flexographic printing press (so-called "bouncing"; generates unwanted waste). Oscillations in the resonance range are particularly critical. Gaps 306 and 307, also shown as examples, are uncritical in this regard due to their dimensions and / or neighboring / adjacent printing locations 307a. The same applies to gap 308 between the two flexographic printing plates 301 and 302, which are mounted at a distance from one another (e.g., glued to sleeve 300).However, the gap 309 between the leading and trailing edges of the flexographic printing plate 301 can be critical. For example, a mounted printing plate can only occupy 60% of the circumference of the sleeve 300, meaning 40% of the circumference corresponds to the gap 309. Critical gaps are detected computationally and preferably identified as channels.

[0110] Also shown as examples are a register mark 310 and a register mark 311. Also shown are color measurement fields 312 and 313. In the example shown, the marks and fields are arranged in respective control strips 314 and 315. The marks and fields are preferably also captured by the camera 400 and recognized and separated using image processing. Their determined position data (xy localization) is stored under the core ID 316.

[0111] Also shown as an example is a so-called error mark 318 for detecting an assembly error of a flexographic printing form or multiple flexographic printing forms on the sleeve or on multiple sleeves. Their position data is also stored under the sleeve ID 316.

[0112] Figure 6also shows a sensor 402. The sensor 402 can be a register sensor and / or a spectrometer. This is arranged in particular in the flexographic printing unit of the flexographic printing press and directed at the printing material web 11. The sensor is connected to a computer 403 and is motor-driven (by means of the motor 404) movable in the axial y-direction 405 and can thus be positioned automatically. Using the data generated from the image 410 and making it available to the printing press when the sleeve 300 is used, the sensor can be positioned along the printing material 11 to the y-position of a mark 310, 311 to be printed and detected and / or the same or another sensor can be positioned in the field 312, 313 along the printing material 11, e.g., for color inspection with a spectrometer. The data generated by the sensor is forwarded to the computer 403, which may be identical to the computer 401 and / or the computer 39. List of reference symbols

[0113] 1Carrier cylinder 2Measuring station 3Sleeve 3aID of the sleeve 4Adhesive tape 5Printing plate or flexographic printing form 5aID of the printing plate or flexographic printing form 6Rotary body or flexographic printing form 7First motor 8Printing press or flexographic printing press 9Printing unit or flexographic printing unit 10Dryer 11Printing material 12Measuring rings 13Elevations / topography 14Surface 15Anilox roller / Anilox cylinder 15aID of the anilox roller / anilox cylinder 16Printing cylinder 17Impression cylinder / printing material transport cylinder 18Measuring device 19Radiation sources, in particular light sources 20Reflector or mirror 21Radiation receiver, in particular light receiver, e.g.Cameras 22 Rotation axis 23 Light curtain / emitted light 24 Shading 25 Reflected light 26 Working width 27 Axial direction 28 Direction of movement 29 Second motor 29 Second motor 30 Reference object / linear object, especially thread / string / knife / beam 31 Reference line 32 Distance 33 Surface area 34 Unit 35 Circumferential direction 36 Shading 37 Sensor 38 Identification feature or ID 39 Digital computer 39 Further digital computer 40 Digital memory 41 Drive side (AS) 42 Operating side (BS) 43 Device for detecting the dot density 44 Laser micrometer 45 Third motor 46 Measuring line 47 Measuring strip 48 Multiple measuring lines 50 Printing area 51 Non-printing area 52enveloping radius / envelope 53printing point of the printing plate 54just printing point of the printing plate 55non-printing point of the printing plate 56lowest point 57radial distance 58marking means 59measuring field for measuring the Shore hardness 60motor 62device for detecting the ID . 300Sleeve 301Flexographic printing form 302Additional flexographic printing form 303Area of ​​high dot density 304Area of ​​low dot density 305Channel 306Gap, non-printing area 307Gap, non-printing area 307Printing area 308Gap between flexographic printing forms 309Gap 310Registration mark 311Registration mark 312Color measurement patch 313Color measurement patch 314Control bar 315Control bar 316ID 317Memory 318Error mark 400Camera 401Computer 402Sensor 403Computer 404Motor 405Direction of movement 410Image Rradial distance DDiameter xDirection (circumferential direction) yDirection (axial direction)

Claims

1. Method for operating a flexographic printing press with at least one flexographic printing form, with a printing cylinder (16) carrying a sleeve (3) for the flexographic printing form (5) or with a flexographic printing cylinder for the flexographic printing form and with an impression cylinder (17) which forms a printing nip with the printing cylinder or the flexographic printing cylinder, wherein a web (11) of printing material is printed in the printing nip and a transport speed of the web is set, characterized in that the setting is carried out automatically either as a function of a dot density (303, 304) of the flexographic printing form, or of data derived computationally therefrom, or as a function of channels (305, 306, 307, 307a, 308) of the flexographic printing form, of the impression cylinder or of the flexographic printing cylinder, or of data derived computationally therefrom, wherein the dot density is a location-dependent density of printing projections of the flexographic printing form, and wherein the dot density or the channels is / are measured without contact or wherein the dot density is determined computationally from prepress data for producing the flexographic printing form.

2. Method according to claim 1, characterized in that the dot density of the flexographic printing form or the channels is / are measured in a measuring device (2, 18, 400) before printing.

3. Method according to claim 2, characterized in that a camera (18, 400) is used for measuring.

4. Method according to claim 3, characterized in that the entire printed image of a flexographic printing form, the impression cylinder or the flexographic printing cylinder is captured during measurement.

5. Method according one of the preceding claims, characterized in that a calculation of setting values takes place.

6. Method according to claim 5, characterized in that the setting values are transmitted to a controller of a motor (60) for the rotary drive of the impression cylinder, the counter cylinder and / or a screen roller (15) and / or in that the setting values are transmitted to a controller of a motor (60) for conveying the web.

7. Method according to claim 5 or 6, characterized in that different frequencies are calculated for channel impacts at different surface speeds.

8. Method according to claim 5, 6 or 7, characterized in that resonance frequencies of the impression cylinder, the counter cylinder, components of the flexographic printing press, printing units of the flexographic printing press and / or of the flexographic printing press, which are measured and / or specified, are used or excluded in the calculation.

9. Method according one of the preceding claims, characterized in that during operation of the flexographic printing press with one or more previously measured flexographic printing form or flexographic printing forms, such speeds of the impression cylinder are avoided or, when the speed is changed, are overrun or underrun which, as a result of at least one channel impact or channel impact pattern of one channel (305) or several channels (305), generate resonant vibrations which interfere with the print quality.

10. Flexographic printing press, with at least one flexographic printing unit and with at least one flexographic printing form, comprising a printing cylinder (16) carrying a sleeve (3) for the flexographic printing form (5) or a flexographic printing cylinder for the flexographic printing form, a counter cylinder (17) which forms a printing nip with the impression cylinder or the flexographic printing cylinder, and a screen roller (15), wherein the flexographic printing press is operated for printing a substrate (11) with flexographic printing ink according to one of the preceding methods, characterized in that the flexographic printing press comprises at least one drive motor (60) for rotationally driving the impression cylinder, the flexographic printing cylinder, the counter cylinder and / or a screen roller (15) and comprises a drive motor (60) for conveying the web, and in that the drive motor (60) is controlled or excited computationally using the dot density (303, 304) or data derived therefrom, or as a function of the channels (305, 306, 307, 307a, 308), or data derived computationally therefrom, in such a way that the transport speed of the web has a predetermined value or a predetermined range of values or that the transport speed of the web excludes a predetermined value or a predetermined range of values.

11. Flexographic printing press according to claim 10, characterized in that the drive motor is controlled or regulated computationally using the dot density, or data derived therefrom, or as a function of channels of the flexographic printing form, the impression cylinder or the flexographic printing cylinder, or data derived computationally therefrom, in such a way that the transport speed of the web has a predetermined value or a predetermined range of values or that the transport speed of the web excludes a predetermined value or a predetermined range of values.

12. Flexographic printing press according to claim 10 or 11, characterized in that a channel is formed between the flexographic printing form and another flexographic printing form.

13. System comprising a flexographic printing press according to claim 10, 11 or 12 and a measuring device (2, 18, 400) for measuring the dot density of the flexographic printing form (5) characterized in that the measuring device measures the dot density of the flexographic printing form or measures channels (305, 306, 307, 307a, 308) of the flexographic printing form, the impression cylinder or the flexographic printing cylinder and that the measuring device transmits the dot density or the channels, or data computationally derived therefrom, to the flexographic printing press.

14. System according to claim 13, characterized in that the flexographic printing form or the sleeve is marked with a machine-readable ID (3a, 5a, 38, 316).

15. System according to claim 14, characterized in that the ID is designed as a unique identifier for the sleeve.

16. System according to claim 13, 14, or 15, characterized in that the measuring device indirectly transmits the dot density or the channels, or data derived computationally therefrom, together with the ID to the flexographic printing press by temporarily storing the dot density or the channels, or the data derived therefrom, and retrieving them from the flexographic printing press for printing with the flexographic printing form and / or the sleeve.

17. System according to claim 16, characterized in that the derived data comprises at least one channel pattern or a frequency corresponding to a channel pattern.