DE102021119702A1 - Method for operating a printing machine with a cleaning process - Google Patents

Abstract

The invention relates to a method for operating a printing machine, the printing machine having an inkjet print head with ejection openings, with each ejection opening being assigned an activation element and with at least one test print image being generated in a test printing process by a respective volume of the respective application fluid being ejected from ejection openings, which hits a test section of the substrate and the test print image is detected by a sensor device in a detection process and a digital test image is generated in the process and the digital test image is analyzed in an evaluation process and deviations from a stored test pattern are detected, the respective activation elements and/or ejection openings are assigned and thereby an assignment specification is generated and wherein faulty and acceptable activation elements are defined by the assignment specification and wherein cleaning methods Uberdaten are generated, for the generation of which both the assignment rule and cleaning sequence data are used and in a cleaning process, the faulty activation elements are operated on the basis of the cleaning control data while acceptable activation elements remain deactivated.

Description

The invention relates to a method for operating a printing press with a cleaning process according to the features of claim 1.

Inkjet printheads are used in inkjet printing machines in order to apply respective application fluid to respective substrate. The application fluid is, for example, an ink of a corresponding color. A plurality of different inks with different colors, for example cyan, magenta, yellow and black, are usually used in an ink-jet printing machine for multi-color printing. The ink is applied in that during a relative movement between a corresponding print head and the substrate, droplets of the application fluid are ejected in a targeted manner and impinge on the substrate, so that the entirety of the applied drops results in a desired print image. A respective activation element is activated for each individual ejection process. The activation element causes displacement of application fluid from a corresponding cavity of the printhead, causing a corresponding amount of application fluid to be ejected through an ejection orifice or nozzle from the printhead. The respective activation element can be a thermocouple or a piezo element, for example.

Depending on how a profile of a voltage applied to the activation element is selected, a different volume is ejected and the form in which droplets that hit the substrate are formed can be influenced. For this it is important that the ejection openings are in an acceptable condition. In particular, this means that they are capable of ejecting surface fluid in a desired form when properly commanded. Ejection orifices that are not in an acceptable condition are referred to as defective ejection orifices. Ejection openings that are in an acceptable condition are referred to as acceptable ejection openings. Errors are often caused by contamination, for example due to dried application fluid that completely or partially closes the ejection opening. Depending on how the error shows up in the printed image, the corresponding defective ejection opening is referred to as a missing nozzle ("missing nozzle"), deviated nozzle ("deviating nozzle") or weak nozzle ("weak nozzle"). A missing nozzle causes no transfer of application fluid to the substrate despite activation. A deflected nozzle causes application fluid to be transferred to the substrate, but with a deviation from the target location. A weak nozzle causes application fluid to be transferred to the substrate, but in a smaller volume or quantity than intended. Mixtures and transitions between each category of defective ejection orifice also occur. Depending on the case, the print quality is negatively influenced by defective ejection openings, for example by defects and/or stripes and/or inhomogeneous color densities, which can ultimately lead to unusable printed products.

Measures are known by means of which faulty ejection openings can be reactivated, that is to say they can be brought back into an acceptable state. One approach is to leave cleaning agents on the printhead. This variant results in the use of relatively large amounts of cleaning agent, in particular because the entire nozzle surface of the print heads is often provided with cleaning agent for this purpose. Another approach is to remove soiling mechanically, for example by wiping with a cleaning fleece or a squeegee. This is associated with the risk of damaging the nozzle surface of the print head. Another approach is to remove the corresponding printheads and clean them externally. This leads to long downtimes and requires the printing press to be recalibrated afterwards. Another approach is to flush ejection openings with the respective application fluid in order to flush out dirt. Since all the ejection openings are used here, in particular because of the design of the print heads, and the ejection fluid will also flow along the path of least flow resistance, the consumption of application fluid is relatively high. A further approach to reactivating the defective ejection openings is the continuous activation of the activation elements when printing print patterns with high color density. This also results in a high consumption of application fluid and also creates waste, ie an increased consumption of substrate.

through the U.S. 10,882,320 B2 a method is known in which defective nozzles are counted and defective nozzles are counted again after a cleaning process.

through the WO 2019 /152016 A1 a method is known in which defective nozzles are detected and, if necessary, a print head is cleaned by wiping.

through the WO 2020/007791 A1 a test print image is known.

The invention is based on the object of creating a method for operating a printing press with a cleaning process.

The object is achieved according to the invention by the features of claim 1.

A method for operating a printing press includes at least one test printing process, a detection process, an evaluation process and a cleaning process. The printing machine has at least one print head designed as an ink jet print head. The at least one printhead has a first set of ejection orifices. This first quantity is preferably greater than, more preferably greater than 30, even more preferably greater than 100, even more preferably greater than 300 and even more preferably greater than 1000. Each ejection opening is assigned an activation element, with this being used in particular to eject an application fluid can be effected through the respective ejection opening. The at least one print head preferably has at least one nozzle surface and this plurality of ejection openings are designed as openings of the at least one nozzle surface. In the test printing process, at least one test print image is generated by moving at least one test section of a substrate and the at least one print head relative to one another, for example by moving at least one test section of a substrate relative to the at least one print head, and thereby from a plurality of the ejection openings of this first Amount a respective volume of the respective application fluid is ejected, which impinges on the test section of the substrate and thereby contributes to the generation of the test print image.

In the detection process, the at least one printed test print image is detected using at least one in particular internal or external sensor device and a digital test image is generated in the process. In the evaluation process, the at least one digital test image is analyzed and deviations from a stored test pattern are recorded. In particular, in an association process, the detected deviations are associated with respective activation elements and/or ejection openings, and at least one association rule is generated in the process. The at least one assignment rule specifies faulty activation elements and acceptable activation elements. Cleaning control data is generated, with both the at least one assignment rule and cleaning sequence data being used to generate the cleaning control data. In a particularly first cleaning process, the faulty activation elements are operated on the basis of the cleaning control data, while acceptable activation elements remain at least partially and preferably completely deactivated. The faulty activation elements preferably eject application fluid on the basis of the cleaning control data. The advantages that can be achieved with the invention are, in particular, that a reactivation of nozzles of a print head that are incorrectly printing can be achieved in order to ensure print quality. In particular, downtimes of the printing press and waste are kept to a minimum. In particular, application fluid, for example ink, is saved. If necessary, even a complex exchange of print heads can be avoided.

Defectively printed ejection openings can be detected by means of the test print image with the aid of a sensor device, with incorrectly printed points in the test print image being able to be assigned to the position of the affected ejection opening in the corresponding print head. A digital template can be created so that only the affected ejection openings of the at least one print head are controlled. A respective deviation from the stored test pattern is to be understood as meaning preferably missing functional test elements and/or incorrectly placed functional test elements and/or functional test elements that are printed too faintly.

In an alternative or additional development, the method is preferably characterized in that this sensor device is part of the printing press. The method can then be carried out particularly quickly and substrate can be saved if necessary because of the relatively short transport distances. In an alternative or additional development, the method is preferably characterized in that the respective application fluid is a respective ink assigned to this respective activation element and/or the respective print head. In an alternative or additional development, the method is preferably characterized in that the substrate and/or means of transport of the printing machine for the substrate are stationary during the cleaning process, particularly in the area of the printing points. Then no substrate is consumed. In an alternative or additional development, the method is preferably characterized in that the print heads to be cleaned are in a cleaning position during the first cleaning process, which differs from a printing position in which the print heads to be cleaned are located during regular printing operation. A cleaning device can then be brought into the area of the ejection openings, in particular in order to collect the application fluid. In an alternative or additional development, the method is preferably characterized in that the application fluid is ejected during the cleaning process into a collecting device of a cleaning device of the printing press. Waste can be saved by a virtual impression in the cleaning device. In particular, no substrate such as paper, foil, wooden boards, etc. is consumed.

In an alternative or additional development, the method is preferably characterized in that the cleaning control data are generated by superimposing the at least one assignment specification with the cleaning sequence data. A particularly simple and comprehensible selection of the activation elements to be used then results. In an alternative or additional development, the method is preferably characterized in that those activation elements are defined by the cleaning control data that are intended to ensure the ejection of application fluid in the cleaning process. In an alternative or additional development, the method is preferably characterized in that the cleaning control data for each of these activation elements stores a cleaning sequence that directly or indirectly defines their activity in the cleaning process. A virtual or emulated printing process can then be carried out. In an alternative or additional development, the method is characterized in particular by the fact that the respective cleaning sequence defines a profile of an electrical voltage applied to the respective activation element and/or that the respective cleaning sequence defines a sequence of drops to be ejected.

In an alternative or additional development, the method is preferably characterized in that the at least one assignment rule is in the form of a text file, in particular in xml format or in txt format. Thus, the assignment is also easy to understand. In an alternative or additional development, the method is preferably characterized in that a cleaning template designed as a file is processed by a computer device of the printing press in order to generate the cleaning sequence data. At least one raster image processor is preferably used here. An emulated printing process can then be used as the cleaning process in a particularly simple manner. In an alternative or additional development, the method is preferably characterized in that this file specifies at least one image and is defined in a page description format or in a raster graphics format. This makes emulation even easier, especially when it comes to a file format that is also used for normal printing.

In an alternative or additional development, the method is preferably characterized in that after the first cleaning process, a test print image is again generated on the substrate, which is then in turn recorded and evaluated by the sensor device. The success of the procedure can then be checked and, if necessary, repeated for further improvement. In particular, I have a direct comparison carried out. Documentation for later use is also possible in this way. This is particularly advantageous when the method is used cyclically. In addition to regular use, the method can also only be used when necessary, especially when it is dirty or when a new or serviced print head is installed.

Exemplary embodiments of the invention are shown in the drawings and are described in more detail below.

• 1 eine schematische Darstellung einer Rollendruckmaschine;
• 2 eine schematische Darstellung einer Bogendruckmaschine;
• 3 eine schematische Darstellung einer Ausstoßöffnung und eines Aktivierungselements eines Druckkopfs;
• 4 eine schematische Darstellung von Druckköpfen und Druckstellen;
• 5 eine schematische Darstellung von Abläufen in einem normalen Druckbetrieb;
• 6 eine schematische Darstellung von Abläufen in einem Prüfdruckvorgang;
• 7 eine schematische Darstellung eines Prüfdruckbilds;
• 8 eine schematische Darstellung eines Druckkopfs;
• 9 eine schematische Darstellung eines Funktionsprüfungsbereichs eines Prüfdruckbilds;
• 10 eine schematische Darstellung einer Lageprüfform eines Prüfdruckbilds;
• 11 eine schematische Darstellung von Abläufen in einem Reinigungsdruckvorgang;
• 12 eine schematische Darstellung von Druckköpfen, die teilweise in einer Druckposition und teilweise abgestellt angeordnet sind;
• 13 eine schematische Darstellung von Druckköpfen, die teilweise in einer Druckposition und teilweise in einer Reinigungsposition angeordnet sind;
• 14 eine schematische Darstellung einer ersten Reinigungsvorlage;
• 15 eine schematische Darstellung einer ersten Reinigungssequenz, die auf einer Reinigungsvorlage gemäß 14 basiert;
• 16 eine schematische Darstellung einer zweiten Reinigungsvorlage;
• 17 eine schematische Darstellung einer ersten Reinigungssequenz, die auf einer Reinigungsvorlage gemäß 16 basiert;
• 18 eine schematische Darstellung einer dritten Reinigungsvorlage;
• 19 eine schematische Darstellung einer ersten Reinigungssequenz, die auf einer Reinigungsvorlage gemäß 18 basiert.

Show it:

• 1 a schematic representation of a web press;
• 2 a schematic representation of a sheet-fed printing machine;
• 3 a schematic representation of an ejection opening and an activation element of a print head;
• 4 a schematic representation of print heads and pressure points;
• 5 a schematic representation of processes in a normal printing operation;
• 6 a schematic representation of processes in a proof printing process;
• 7 a schematic representation of a test print image;
• 8th a schematic representation of a print head;
• 9 a schematic representation of a function test area of a test print image;
• 10 a schematic representation of a position test form of a test print image;
• 11 a schematic representation of processes in a cleaning printing process;
• 12 a schematic representation of printheads arranged partially in a printing position and partially parked;
• 13 a schematic representation of print heads, which are partially in a print posi tion and partially arranged in a cleaning position;
• 14 a schematic representation of a first cleaning template;
• 15 a schematic representation of a first cleaning sequence based on a cleaning template 14 based;
• 16 a schematic representation of a second cleaning template;
• 17 a schematic representation of a first cleaning sequence based on a cleaning template 16 based;
• 18 a schematic representation of a third cleaning template;
• 19 a schematic representation of a first cleaning sequence based on a cleaning template 18 based.

A printing press 01 is preferably embodied as an inkjet printing press 01. Printing press 01 preferably has at least one inkjet printing unit 04 embodied as an inkjet printing unit 04. For example, the printing press 01 exclusively has printing units 04 that are embodied as inkjet printing units 04. Alternatively, in addition to at least one inkjet printing unit 04, printing press 01 has at least one printing unit 06 or application unit 06 that operates according to a form-based printing process. Printing press 01 and/or the at least one inkjet printing device 04 preferably has at least one inkjet print head 03 and more preferably a plurality of inkjet print heads 03. The at least one inkjet print head 03 is preferably embodied as a piezo print head 03 and is also referred to simply as print head 03. Printing press 01 is preferably used for printing substrate 02 or printing material 02. Substrate 02 is embodied, for example, as a substrate web 02 or as at least one and preferably a large number of sheets 02. The printing press 01 is embodied, for example, as a web-fed printing press 01 or as a sheet-fed printing press 01.

The substrate 02 is preferably transported along a transport path and/or in a transport direction T through the printing press 01 and/or through the at least one inkjet printing unit 04. A transport path for transporting substrate 02, in particular printing substrate 02 and/or sheets 02, is preferably provided. The transport path provided for the transport of printing substrate 02 is, in particular, the spatial region that printing substrate 02 occupies and/or would occupy at least temporarily if it were present. The transport direction T provided in particular for transporting sheets 02 is a direction T which is preferably oriented at least essentially and more preferably completely horizontally and/or which preferably points from a first unit of printing press 01 to a last unit of printing press 01, in particular from a material source 08; 09 to a substrate delivery device 12; 13.

The at least one print head 03 serves in particular to apply application fluid to a respective substrate 02. Different fluids can be used as the application fluid. The application fluid is designed, for example, as a primer or as an ink or as a paint. In the foregoing and in the following, the term printing press 01 is also to be understood as meaning a device that is designed and/or used solely for the application of primer and/or paint to substrate 02. Printing press 01 is embodied, for example, as a sheet-fed printing press 01, i.e. in particular as a printing press 01 for applying application fluid to a sheet-shaped substrate 02 or sheet 02, in particular sheet-shaped printing substrate 02. Printing press 01 is embodied, for example, as a sheet-fed corrugated cardboard printing press 01, i.e. as a printing press 01 for applying Application fluid onto sheet-like substrate 02 or sheets 02 made of corrugated cardboard 02, in particular sheet-like printing material 02 made of corrugated cardboard. In an alternative embodiment, printing press 01 is embodied as a web-fed printing press 01, i.e. in particular as a printing press 01 for applying application fluid to web-type substrate 02, in particular web-type printing material, also referred to as web 02 or material web 02.

In the foregoing and in the following, the term sheet-shaped substrate 02, in particular a printing material 02, specifically sheet 02, is intended to encompass any flat substrate 02 or any substrate 02 that is present in sections, i.e. also substrates 02 that are in the form of panels or plates, i.e. also panels or plates . The sheet-like substrate 02 or sheet 02 defined in this way is formed, for example, from paper or cardboard, ie as a sheet of paper or cardboard, or from sheets 02, panels or possibly panels made of plastic, cardboard, glass or metal. The substrate 02 is more preferably corrugated cardboard 02, in particular corrugated cardboard sheets 02. The thickness of a sheet 02 is preferably understood to mean a dimension orthogonal to a largest area of the sheet 02. This largest area is also referred to as the main area. The thickness of the sheets 02 is, for example, at least 0.1 mm, more preferably at least 0.3 mm and even more preferably at least 0.5 mm. Especially with sheets of corrugated cardboard 02, significantly greater thicknesses are also common, for example at least 4 mm or even 10 mm and more. Corrugated cardboard sheets 02 are comparatively stable and therefore not very flexible. Corresponding adjustments to the printing press 01 therefore make it easier to process thick sheets 02.

Printing machine 01 preferably has at least one material source 08; 09, which, depending on the type of printing press 01, is embodied, for example, as a sheet feeder 08 or, for example, as a roll unwinding device 09 and/or roll changer 09. Printing press 01 preferably has at least one drying system 11. Printing machine 01 has, for example, at least one substrate delivery device 12; 13, which, depending on the type of printing press 01, is embodied, for example, as a sheet delivery 12 or, for example, as a winding device 13.

The at least one inkjet printing device 04 has, for example, at least one printhead assembly 29, which extends over the entire working width of the inkjet printing device 04 and/or the printing press 01. This print head arrangement 29 has at least one print head 03 and preferably a plurality of print heads 03. If there is only one print head 03 per print head arrangement 29, this one print head 03 preferably extends over the entire working width of the inkjet printing device 04 and/or the printing press 01. However, the case in which a plurality of print heads 03 together form the respective print head arrangement 29 and with their together cover the entire working width of inkjet printing device 04 and/or printing press 01. The working width of inkjet printing unit 04 and/or printing machine 01 is preferably defined as the maximum width that a substrate 02 may have in order to still be able to be processed using inkjet printing unit 04 and/or printing machine 01 and/or corresponds to the maximum using the inkjet printing device 04 and/or printing machine 01 of the respective substrate 02. The working width of printing machine 01 is preferably at least 100 cm, more preferably at least 150 cm, even more preferably at least 160 cm, even more preferably at least 200 cm and even more preferably at least 250 cm. The at least one print head 03 is preferably embodied as a fixed or stationary print head 03 during printing operation. This means in particular that a relative movement required for printing between the substrate 02 on the one hand and the at least one print head 03 on the other hand is preferably implemented exclusively by a corresponding movement of the substrate 02.

The at least one print head 03; 07; 27 has a plurality of ejection openings 26, which are also referred to as nozzles 26. A respective activation element 28 is preferably assigned to each ejection opening 26 . The respective activation element 28 is designed, for example, as a piezoelectric element 28 or as a thermocouple. The respective activation element 28 is preferably an activation element 28 by means of which a respective application fluid can be ejected through the respective ejection opening 26 . The respective activation element 28 serves in particular to displace application fluid and thereby eject it from the respective ejection opening 26 when actuated accordingly, in particular when a corresponding electrical voltage is applied. The activation elements 28 are preferably also part of the respective print head 03; 07; 27. For example, each print head 03; 07; 27 has a plurality of print head elements, which in turn each have a plurality of ejection openings 26 and activation elements 28 . For example, the at least one print head 03; 07; 27 has a nozzle surface 36 . This nozzle surface 36 is, for example, that surface through which the ejection openings 26 pass. Correspondingly, this plurality of ejection openings 26 are designed as openings 26 of the at least one nozzle surface 36 . The respective application fluid is preferably a respective one of this respective activation element 28 and/or the respective print head 03; 07; 27 associated ink.

Inkjet printing machine 01 preferably has at least one first printing position 16 for a first ink. At least one first inkjet print head 03 is preferably assigned to this first printing point 16. The first ink preferably has a first color. Under a respective pressure point 16; 17; 18; 19 is preferably to be understood as the area in which ink drops of one of these printing points 16; 17; 18; 19 associated color are or can be applied to the substrate 02. The inkjet printing machine 01 preferably has at least one second printing position 17 for a second ink. At least one second inkjet print head 03 is preferably assigned to this second printing point 17. The second ink is preferably a second color, more preferably different from the first color. Inkjet printing machine 01 preferably has at least one third printing point 18 for a third ink. At least one third inkjet print head 03 is preferably assigned to this third printing point 18. The third ink is preferably a third color, more preferably different from the first color and from the second color. Inkjet printing machine 01 preferably has at least one fourth printing point 19 for a fourth ink. This fourth pressure point 19 is preferred at least one fourth inkjet print head 03 assigned. The fourth ink preferably has a fourth color, which more preferably is different from the first color and from the second color and from the third color. Depending on requirements, the inkjet printing machine 01 has additional printing points for additional inks.

Inkjet printing machine 01 has, for example, at least one first priming point 33 for at least one first priming agent. At least one print head 07 referred to as the first priming head 07 is preferably assigned to this first priming point 33. Inkjet printing machine 01 also has, for example, at least one second priming point 34 for at least one second priming agent, which more preferably differs from the first priming agent. At least one print head 27 referred to as the second priming head 27 is preferably assigned to this second priming point 34 . The at least one priming head 07; 27 denoted print head 07; 27 is also available, for example, as an inkjet print head 07; 27 and/or piezo print head 07; 27, i.e. it works in particular like the at least one print head 03 provided for ejecting ink. Under a print head 03; 07; 27 is intended in the foregoing and in the following, accordingly, both a print head 03 of a printing position 16; 17; 18; 19 and a print head 07; 27 a primer site 33; 34 to be understood. Depending on requirements, the inkjet printing machine 01 has further priming points for further priming agents. For example, one primer can serve as a full-surface primer, while another primer is only relevant for certain areas.

The at least one first priming point 33 is arranged in front of the at least one first printing point 16, more preferably in front of each printing point 16; 17; 18; 19. At least one drying device 11 is preferred after the first printing point 11 and more preferably after each printing point 16; 17; 18; 19 arranged. For example, at least one drying device 11 is provided along the transport path provided for the transport of substrate 02 before the first printing point 11 and after the first priming point 33, more preferably after each priming point 33; 34 arranged.

A print head assembly 31 is preferably to be understood as meaning at least one assembly 31, which comprises at least one print head 03; 07; 27 and preferably several print heads 03; 07; 27 and which has, for example, at least one support body on which the at least one print head 03; 07; 27 is attached directly or indirectly and relative to which the at least one print head 03; 07; 27 is arranged stationary in a normal printing operation. A relative movement takes place, for example, for adjustment purposes and/or for assembly purposes. In particular, the printhead assembly 31 includes the printhead assembly 29 .

At least one print head 03; 07; 27 is and/or can be connected to at least one positioning device 91 directly and/or via its corresponding print head assembly 31. This at least one print head 03; 07; 27 by means of the at least one positioning device 91 so that it can be moved relative to a frame 94 of the inkjet printing unit 04, in particular at least with respect to a vertical direction V and/or by at least 0.5 cm, more preferably at least 2 cm and even more preferably at least 10 cm and even further preferably arranged to be movable by at least 25 cm. In one embodiment, the at least one positioning device 91 has at least one positioning guide and more preferably a plurality of positioning guides and even more preferably one positioning guide per movable print head assembly 31. The at least one print head 03; 07; 27 by means of the positioning device 91 assigned to it can be arranged at least either in a printing position assigned to it or in at least one cleaning position assigned to it. A print head 03; 07; 27 characterized in that at least one ejection opening 26 of this respective print head 03; 07; 27 is at a distance from the transport path provided for the transport of substrate 02 and/or from substrate 02 which is at most 5 mm and more preferably at most 1.5 mm and/or which is preferably at least 0.5 mm and more preferably at least 1 mm. In one embodiment, the at least one positioning device 91 has at least one positioning guide. Each of the print heads 03; 07; 27 can be optionally arranged at least either in a printing position assigned to it and at least in a cleaning position assigned to it by means of the respective positioning device 91.

At least one cleaning device 92 for cleaning print heads 03; 07; 27 and/or nozzle surfaces 36 of print heads 03; 07; 27 and/or at least one print head 03; 07; 27 and/or at least one nozzle surface 36 of the at least one print head 03; 07; 27 assignable and/or assigned. The at least one cleaning device 92 is preferably arranged to be movable along at least one supply path between at least one parked position and at least one use position, in particular by means of at least one feed system 93. In the respective cleaning position of a respective print head 03; 07; 27 at least one cleaning device 92 of at least one ejection opening 26 of this print head 03; 07; 27 assigned and/or assignable. When the print head 03; 07; 27 at least one cleaning device 92 between at least one ejection opening 26 of the at least one print head 03; 07; 27 and an area of the transport path provided for the transport of substrate 02 that is closest to this at least one ejection opening 26 and/or can be arranged. The at least one cleaning device 92 preferably has at least one collecting device, which is embodied in particular as a collecting pan. The at least one catching device preferably has a dimension in the transverse direction A that is larger than the working area of the at least one print head arrangement 29. For example, printing press 01 has at least four cleaning devices 92, each of which has a catching device. Drops of the application fluid discharged from the discharge openings 26 to be cleaned are preferably caught by the collecting device.

For example, the at least one cleaning device 92 has at least one option for applying a cleaning agent to a respective nozzle surface 36 of at least one print head 03; 07; 27 to apply and to remove it again.

At least one and more preferably exactly one sensor device 63 or print image sensor device 63 is preferably provided, by means of which a print quality that can be generated with printing press 01 can be checked in particular. This sensor device 63 is then embodied in particular as an internal sensor device 63 of printing press 01. A detection range of the at least one sensor device 63 preferably extends over the entire working width of printing press 01 and/or the at least one sensor device 63 is stationary with respect to transverse direction A. The at least one sensor device 63 has, for example, a detection area that is defined by a plurality of sensor elements, for example pixels. For example, the at least one sensor device 63 is embodied as at least one and more preferably as exactly one line camera 63. For example, the at least one sensor device 63 is part of an inspection device. In the event of a linear relative movement between sensor device 63 and substrate 02, the at least one sensor device 63 can be used, for example, to detect a printed area of a respective substrate 02, for example an entire printed area of the respective substrate 02, in particular to check the print quality and/or the functionality of the print heads 03; 07; 27. In a printing operation, for example, register marks can be detected by means of the at least one sensor device 63.

For example, print control data 41 is made available to the print heads 03 for printing using the inkjet printing machine 01. For this purpose, for example, in a corresponding conversion process, print control data 41 for the inkjet print heads 03 is generated from, in particular, digital template image data 38 of a template image 39 in order to generate a print image 42 printed in particular on the substrate 02. The print control data 41 is preferably generated by means of a computer device 14, which is more preferably a component of the printing press 01 and/or its machine controller. The conversion process includes, for example, the usual processes such as halftoning, screening, etc., which are necessary to generate print control data 41 . The computing device 14 is embodied, for example, as at least a raster image processor 14 and/or has at least one raster image processor 14 . (This is also shown schematically, for example, in 5 shown.)

The print control data 41 have information about pixels to be generated, for example. This print control data 41 preferably contains information that corresponds directly or indirectly to information about the location at which pixels are to be generated and/or the size of these pixels and/or when the ink drops required for this are to be ejected and/or the size of such ink drops . In the case of piezo print heads 03, such information can represent a course of a voltage applied to a piezo element 28, for example. This information is preferably stored for each relevant application fluid, in particular each relevant ink.

The print control data 41 define, for example, at least one first color separation 21, to which first pixels of a first color to be generated are assigned. The print control data 41 preferably define at least one second color separation 22, to which second pixels to be generated, of a second color that is different in particular from the first color, are assigned. In an alternative or additional development, the print control data 41 define at least one third color separation 23, to which third pixels to be generated are assigned a third color that is different in particular from the first and the second color. In an alternative or additional development, the print control data 41 define at least one fourth color separation 24, the fourth pixels to be generated, in particular the first and the second and the third color are associated with different fourth color. In particular when more than four differently colored inks are used, there are preferably a corresponding number of color separations, for example five, six, seven, eight or even more. Any color separation 21 is preferred; 22; 23; 24 of a respective pressure point 16; 17; 18; 19 assigned to the inkjet printing machine 01.

In an alternative or additional development, the template image data 38 is in the form of page description data and/or written in a page description language, for example as a pdf document (Portable Document Format).

A method for operating a printing press 01 includes at least one test printing process. Printing machine 01 has at least one inkjet print head 03; 07; 27 formed print head 03; 07; 27, wherein the at least one print head 03; 07; 27 has a first set of ejection openings 26 and each ejection opening 26 is assigned an activation element 28 . Ejection of an application fluid through the respective ejection opening 26 can preferably be effected by means of the respective activation element 28 . The first set of ejection openings 26 is preferably greater than 10, more preferably greater than 30, even more preferably greater than 100, even more preferably greater than 300 and even more preferably greater than 1000. The at least one print head 03; 07; 27 has at least one nozzle surface 36. This plurality of ejection openings 26 are designed as openings 26 of the at least one nozzle surface 36 .

In the test printing process, at least one test print image 47 is generated by at least one test section 32 of a substrate 02 relative to the at least one print head 03; 07; 27 is moved and a respective volume of the respective application fluid is ejected from a plurality of the ejection openings 26 of this first quantity, which impinges on the test section 32 of the substrate 02 and thereby contributes to the generation of the test print image 47. In particular, the at least one print head 03; 07; 27 and preferably at least two print heads 03; 07; 27 of printing press 01 generates at least one proof print image 47, in particular on at least one substrate 02, in at least one proof printing process.

In a detection process, the at least one printed test print image 47 is detected using at least one sensor device 63 and a digital test image 66 is generated in the process. Sensor device 63 is preferably embodied as a sensor device of printing press 01, in particular as an internal sensor device 63. Alternatively, an external sensor device 63 can be used.

The at least one test print image 47 is preferably generated using a test print template 67 specified in advance. This test print template 67 is preferably a standardized test print template 67, by means of which a respective test print image 47 is generated repeatedly and at different times in order to check and/or optimize settings and/or states of printing press 01. For example, test print template 67, from which test print image 47 is generated, is stored permanently in at least one memory of printing press 01, in particular independently of image data from other print jobs. Alternatively, the test print image 47 represents at least part of a print image of a print job, which is processed and/or analyzed accordingly in order to be able to derive corresponding information from it.

Test control data 69 is preferably made available to the print heads 03 for printing the at least one test print image 47 using the inkjet printing machine 01. In a first embodiment, test control data 69 for the at least one print head 03; 07; 27 for generating a test print image 42 printed in particular on the substrate 02. For example, at least one test print template 67 is stored, for example in a memory of printing press 01 and/or machine controller 14 of printing press 01. This at least one test print template 67 is preferably stored permanently in this memory or, alternatively, is loaded into this memory for the test printing process. The test control data 69 is generated, for example, by means of a computer device 14, which is more preferably a component of the printing press 01 and/or its machine controller. The conversion process includes, for example, usual processes such as halftoning, rasterization, etc., which are necessary in order to generate test drive data 69 . The computer device 14 is, for example, identical to the computer device 14 that is used to generate the print control data 41 in normal printing operation. (This is also shown schematically, for example, in 6 shown.) In a second embodiment, the test control data 69 is stored permanently and is called up for the test printing process. For example, the test control data 69 is in a memory of the printing press 01 and/or a machine controller 14 of the printing press 01 and/or a directly associated with the respective print head 03; 07; 27 associated memory stored or these test control data 69 are loaded into such a memory for the test printing process.

The test control data 69 have, for example, information about pixels to be generated and/or droplets of an application fluid to be ejected. This test control data 69 contains, for example, information that directly or indirectly corresponds to information about the location at which pixels are to be generated and/or what size these pixels are to have and/or when the necessary drops of application fluid, in particular ink drops, are to be ejected and/or which ones Size should have such drops of application fluid, especially ink drops. In the case of piezo print heads 03, such information can represent a course of a voltage applied to a piezo element 28, for example. In the case of thermal printheads, such information can represent, for example, a course of a voltage applied to a thermocouple. This information is preferably stored for each relevant application fluid.

The test control data 69 define, for example, at least one first test extract 77 to which first pixels to be generated and/or drops to be ejected of a first color are assigned. The test control data 69 preferably define at least one second test extract 78, to which second pixels to be generated and/or droplets to be ejected of a second color, in particular different from the first color, are assigned. In an alternative or additional development, the test control data 69 define at least one third test extract 79, to which third pixels to be generated and/or droplets to be ejected of a third color, in particular different from the first and the second color, are assigned. In an alternative or additional development, the test control data 69 define at least one fourth test extract 81 to which fourth pixels and/or droplets to be generated are assigned a fourth color that differs in particular from the first and the second and the third color. In particular if more than four differently colored inks are used, there are preferably a corresponding number of test extracts, for example five, six, seven, eight or even more. Any audit statement 77 is preferred; 78; 79; 81 of a respective printing point 16; 17; 18; 19 assigned to the printing machine 01.

In the detection process, the at least one printed test print image 47 is detected using the at least one sensor device 63. In a first embodiment of the method or of the sensor device 63, this sensor device 63 is part of the printing press 01 and is referred to, for example, as an internal sensor device 63 of the printing press 01. In this case, the at least one sensor device 63 is arranged within printing press 01, in particular aligned with the transport path provided for the transport of printing substrate 02. In a second embodiment of the method or of the sensor device 63, this sensor device 62 is embodied as an external sensor device 62, i.e. in particular arranged outside of the printing press 01. In particular, a digital test image 66 is preferably generated in the detection process, regardless of whether it is an internal or an external sensor device 63 . The digital test image 66 represents the printed test print image 47. Faulty locations in the printed test print image 47 can therefore be identified by analyzing the test image 66. The digital test image 66 can be designed as an image of the entire test print image 47 . Alternatively, the digital test image 66 is, for example, divided into several components, for example one component per test statement. Alternatively or additionally, digital test image 66 is a data stream that is already being partially analyzed with regard to parts of test print image 47, while it is still being created with regard to other parts of test print image 47, in particular by means of the at least one sensor device 63.

The at least one digital test image 66 is analyzed in an evaluation process. Deviations from a stored test pattern 67; 68 recorded. This analysis is preferably carried out using a computer device 14; 37, further by means of a computer device 14; 37 of the printing press 01. In one embodiment, this computer device 14 is at least partially identical to the computer device 14 that is used to generate the print control data 41 in normal printing operation and/or to the computer device 14 that is used to generate the test control data 69 and/or with the machine controller 14 of the printing press 01. Alternatively or additionally, another computer device 37 is used for this analysis, for example a computer device 37 assigned to the at least one sensor device 63. In the evaluation process, deviations from a stored test pattern 68; 67 recorded. The deposited test pattern 67; 68 is, for example, identical to the test print template 67. Alternatively, the stored test pattern 68 is stored independently of the test control data 69, particularly in the case where the test control data 69 is permanently stored as such and is not generated again from a test print template 67 for each test print process. The stored test pattern represents a target state that the test print image 47 is intended to achieve. With a respective deviation from the stored test pattern 67; 68 are, for example, missing functional test elements 57 and/or misplaced functional test elements 57 and/or functional test elements 57 printed too lightly.

The detected deviations are assigned to respective activation elements 28 and/or respective ejection openings 26 in particular in an assignment process. This is possible in particular because each function test element 57 is assigned a unique place within the test print image 47 and that the assigned activation element 28 and thus the assigned ejection opening 26 is also stored for each function test element 57 . At least one assignment rule 71 is generated, which is also referred to as a digital template 71, for example. This assignment specification 71 serves to limit measures to be applied later to those activation elements 28 and/or ejection openings 26 for which they are necessary. For example, activation elements 28 with errors and acceptable activation elements 28 are defined by the at least one assignment specification 71 . A faulty activation element 28 is one whose activation has not led to an acceptable function test element 57 . In particular, it is assumed that the problem is contamination of the ejection opening 26 associated with the faulty activation element 28 and not that the corresponding activation element 28 itself is faulty. An example of such an assignment specification 71 is a file, for example a text file, in particular in xml format or in txt format. Other formats are also possible. The assignment specification 71, in particular the named file, assigns an entry to each activation element 28 and/or each ejection opening 26, for example, which entry is selected from two possible entries, for example “on” or “off”. Here, “on” means that the corresponding ejection opening 26 should be cleaned and “off” means that the corresponding ejection opening 26 should not be cleaned. The entries can also be displayed as "1" or "0", for example.

In particular, cleaning control data 72 is generated in a subsequent preparatory process. The structure of this cleaning control data 72 is preferably comparable to print control data 41 and/or test control data 69 . The activation elements 28 relevant in the cleaning process are defined by the cleaning control data 72, that is to say those activation elements 28 which are intended to ensure the ejection of application fluid in a cleaning process. Furthermore, a respective cleaning sequence 82; 83; 84 deposited. This respective cleaning sequence 82; 83; 84 is a rule 82; 83; 84, which directly or indirectly defines a required activity of the respective activation element 28 in the cleaning process. For example, the respective cleaning sequence 82; 83; 84 defines a profile of an electrical voltage applied to the respective activation element 28 and/or a sequence of drops to be ejected, which in particular defines their ejection time and size.

Both the at least one assignment rule 71 and the cleaning sequence data 73 are used to generate the cleaning control data 72 . The specified respective regulation 82 is preferred by the cleaning sequence data 73; 83; 84 or cleaning sequence 82; 83; 84 or activity, in particular the specified profile of the electrical voltage applied to the respective activation element 28, for all activation elements 28. A voltage curve that is particularly effective for cleaning can be stored in advance and by superimposing the at least one assignment specification 71 with this cleaning sequence data 73 in the cleaning control data 72 it can be determined which of the activation elements 28 is operated in this way.

In a first cleaning process, the defective activation elements 28 are operated on the basis of the cleaning control data 72, while acceptable activation elements 28 remain at least partially and preferably completely deactivated. In this case, the faulty activation elements 28 preferably eject application fluid on the basis of the cleaning control data 72 . Defective activation elements 28 are those associated with defective ejection openings 26 . Acceptable activation elements 28 are those associated with acceptable ejection orifices 26 .

For example, a set of cleaning sequence data 73 can be stored permanently in a memory of the printing press 01 and called up when required. This gives the respective cleaning sequence 82 for all activation elements 28; 83; 84 before. The cleaning control data 72 relevant to the situation depending on the situation are then generated by superimposition with the current assignment specification 71 . In an alternative or additional development, several different sets of cleaning sequence data 73 are stored, which are, for example, in the form of the respective cleaning sequences 82; 83; 84 distinguish. The cleaning sequence data 73 to be used are then first selected and then the current assignment rule 71 is superimposed on them. In an alternative or additional development, there are several, for example two or three, different liche cleaning sequences 82; 83; 84 is stored in the cleaning sequence data 73 and the at least one assignment specification 71 has more than two possible entries for the respective activation elements 28, for example “0”, “1”, “2” and “3”. Depending on the entry, this means that the corresponding activation element either has no cleaning sequence 82; 83; 84 has to be performed or a type of cleaning sequence 82 defined by the respective entry; 83; 84 has to perform. This makes sense, for example, when different cleaning sequences 82; 83; 84 appear promising in different ways depending on the type of error in the test print image 42 .

In a preferred alternative or additional development, the cleaning sequence data 73 for the activation elements 28 is created individually before the respective cleaning process, preferably using the computer 14 of the printing press 01, for example the computer 14 that is also used to generate the print control data 41. For this purpose, for example, at least one file 96 designed as a cleaning template 96 is used, which is also referred to as a color file 96 . In a preferred alternative or additional development, a cleaning template 96 configured as a file 96 is processed by a computer 14 of printing press 01 in order to generate cleaning sequence data 73. At least one raster image processor 14 is preferably used here. The cleaning template 96 preferably defines at least one image. This cleaning template 96 is preferably defined in a page description format or in a raster graphic format. This is designed, for example, as a file in pdf format or in tif format or in jpg format or in bmp format or png format or in another appropriate file format. One or more colored areas are defined by the cleaning template 96 . If these are processed by means of the computer device 14, in particular the raster image processor 14, control data which can be used to control the activation elements 28 are thereby generated. With a suitable selection of the colored areas and a corresponding setting of the computer device 14, this computer device 14 is caused to generate the control data in such a way that when these control data are processed by the respective activation elements 28, a respective desired cleaning sequence 82; 83; 84 is run through. Such settings are stored in at least one configuration file 97, for example.

For example, the computer device 14 is set in such a way that based on an area of the cleaning template 96 with a color density of 100% of the corresponding color, it generates control data for generating a first sequence of drops of a first size. For example, the computer device 14 is set so that based on an area of the cleaning template 96 with a color density of 60% of the corresponding color, it generates control data for generating a second sequence of drops of a second size, which are smaller than the drops of the first quantity . For example, the computer device 14 is set in such a way that, based on an area of the cleaning template 96 with a color density of 30% of the corresponding color, it generates control data for generating a third sequence of drops of a third size, which are even smaller than the drops of the second Crowd. For example, the computer device 14 is set in such a way that it generates control data from an area of the cleaning template 96 with a color density of 0% that does not contain a command to eject drops.

By designing the image defined in the cleaning template 96, I then indirectly have a cleaning sequence 82; 83; 84 for each activation element 28 define. If this image defined in the cleaning template 96 is selected, as is preferred, in such a way that it is the same across its entire width, then the cleaning sequence 82; 83; 84 for all activation elements 28 the same. Different cleaning templates 96 can be used to generate correspondingly different cleaning sequence data 73 . By overlaying the cleaning sequence data 73 generated in this way with the applicable assignment specification 71, the cleaning control data 72) are then generated in turn. Thus, a suitable cleaning sequence 82; 83; 84 can be selected, which is then applied only to the actually faulty activation elements 28. This principle can be used accordingly for all existing colors of application fluids. If required, a cleaning template 96 can also be used, which is only assigned to certain colors.

A possible first cleaning sequence 82 has a plurality of voltage pulses of equal magnitude and equal duration. As a result, a corresponding plurality of drops of the same type of the respective application fluid is ejected. (As an example, such a first cleaning sequence 82 is also shown schematically in 15 shown.) A first example of a cleaning template 96 for generating such a first cleaning sequence 82 is shown in 14 shown. It is a monochromatic area of the same color density. In the printed state, this would in turn result in a uniformly colored area on the substrate 02. A possible second cleaning sequence 83 has a first plurality of voltage pulses of the same magnitude and of the same duration, followed by a second plurality of voltage pulses of a different magnitude. This can also be used repeatedly. As a result, a corresponding first plurality of drops of the same type and then a corresponding second plurality of other but similar drops of the respective application fluid are ejected. The sequence of drops can also be repeated accordingly. (Example of such a second cleaning sequence 83 is also in 17 shown.) A second example of a cleaning template 96 for generating such a second cleaning sequence 83 is shown in 16 shown. It is a sequence of monochromatic surfaces with alternating color densities. In the printed state, a striped area would result on the substrate 02. A possible third cleaning sequence 84 is designed analogously to the second cleaning sequence 83, but with a smaller number of uniform voltage pulses in direct succession. (Example of such a third cleaning sequence 84 is also in 19 shown.) A third example of a cleaning template 96 for generating such a third cleaning sequence 84 is shown in 18 shown. It is a sequence of monochromatic areas with alternating color densities, with the stripes being narrower than in the cleaning original 96 for the second cleaning sequence 83. In the printed state, there would be a striped area on the substrate 02, with narrower stripes than when the second cleaning sequence 83. Combinations, modifications or completely different cleaning sequences are also possible and are carried out, for example, depending on the type of soiling.

Irrespective of the way in which the cleaning sequence data 73 was generated or from which source it originates, the cleaning control data 72 is generated by superimposing the at least one assignment rule 71 with this cleaning sequence data 73 . The assignment rule 71 ensures that the cleaning sequence data 73 that are in principle available for all activation elements 28 are ultimately used only for the activation elements 28 that have errors.

The cleaning control data 72 is preferably generated by means of a computer device 14, which is more preferably a component of the printing press 01 and/or its machine controller. This generation includes, for example, the usual processes such as halftoning, screening, etc., which are also necessary to generate print control data 41 . The computing device 14 is embodied, for example, as at least a raster image processor 14 and/or has at least one raster image processor 14 . The computer device is preferably identical to the computer device 14 that is also used to generate the print control data 41 . (An example of a cleaning process is also given in 11 shown schematically.)

The cleaning control data 72 define, for example, at least one first cleaning separation 86, to which the first drops of a first color to be produced are assigned. The cleaning control data 72 preferably define at least one second cleaning separation 87, to which second drops to be produced, of a second color that is different in particular from the first color, are assigned. In an alternative or additional development, the cleaning control data 72 define at least one third cleaning separation 88, to which third drops to be produced, of a third color, in particular different from the first and the second color, are assigned. In an alternative or additional development, the cleaning control data 72 define at least one fourth cleaning separation 89, to which fourth drops to be produced are assigned a fourth color that is different in particular from the first and the second and the third color. In particular if more than four differently colored inks are used, a corresponding number of cleaning extracts are preferably present, for example five, six, seven, eight or even more. Any cleaning statement 86; 87; 88; 89 of a respective pressure point 16; 17; 18; 19 assigned to the inkjet printing machine 01.

As an alternative to the central creation of the cleaning control data 72 by means of the computer device 14, necessary processes can also be distributed to different computer devices, for example to those that exclusively process the respective print heads 03; 07; 37 are assigned, in particular so-called "head driver boards". These can then correspondingly hide or ignore the respective cleaning sequence data 73 for the acceptable activation elements 28 or acceptable ejection openings 26 . This can be implemented, for example, by using the allocation specification 71 to select those activation elements 28 which are then used by the “head driver board” to actually execute the corresponding cleaning sequence 82; 83; 84 be initiated.

In the first cleaning process, the defective activation elements 28 are operated on the basis of the cleaning control data 72 while acceptable activation elements 28 remain at least partially and preferably completely deactivated. The ejection openings 26 assigned to these faulty activation elements 28 preferably eject application fluid on the basis of the cleaning control data 72 . To this In this way, dirt is preferably removed and the faulty activation elements 28 or faulty ejection openings 28 are thus converted into acceptable activation elements 28 or acceptable ejection openings 28 .

The substrate 02 and/or means of transport of the printing press 01 for the substrate 02 preferably stand still during the cleaning process, in particular the first, particularly in the area of the printing points 16; 17; 18; 19. The print heads to be cleaned are preferably located 03; 07; 27 in a cleaning position during the particular first cleaning process. This cleaning position preferably differs from a printing position in which the print heads 03; 07; 27 during regular printing operation.

For example, the at least one print head 03; 07; 27 is initially removed from a substrate 02 and/or from the transport path provided for the transport of substrate 02 and/or is positioned from at least one printing position to at least one cleaning position, in particular by means of the at least one positioning device 91. This is done, for example, by creating a distance between the at least one print head 03; 07; 27 and the transport path provided for transporting substrate 02 is initially increased. The at least one cleaning device 92 is then preferably moved along the supply path and between at least one ejection opening 26 of the at least one print head 03; 07; 27 and an area of the transport path provided for the transport of substrate 02 that is closest to this at least one ejection opening 26. In a preferred embodiment, the at least one print head 03; 07; 27 moves relative to the at least one cleaning device 92. For this purpose, for example, the at least one print head 03; 07; 27 lowered until it is in the cleaning position.

For example, in order to carry out the cleaning process, a machine controller of the printing machine 01 internally specifies an emulated printing speed that corresponds to a transport speed of the substrate 02, with the substrate 02 actually standing still. For example, an emulated printing process of the cleaning template 96 is then started as part of the cleaning process, wherein, as described, special settings of the raster image processor 14 apply to its initialization and the valid assignment rule 71 is taken into account. The cleaning process emulated as a printing process is then preferably carried out while substrate 02 is stationary. The application fluid is preferably ejected into the collecting device of the cleaning device 92 during the cleaning process. Alternatively, a cleaning image 74 can be generated on a waste section 76 of substrate 02 by transporting substrate 02 and ejecting application fluid.

In an alternative or additional development, the method is repeated iteratively. This means in particular that after the first cleaning process, a test print image 42 is generated again on substrate 02, which is then in turn recorded and evaluated by sensor device 63. If necessary, a new cleaning process takes place in accordance with what has been described so far. This also takes place, for example, on the basis of a comparison of the two test print images 42 with one another.

In an alternative or additional development, the method is preferably characterized in that at least one function test process is carried out and/or that preferably exactly one function test process per print head 03; 07; 27 and/or per row of printheads. Ejection openings 26, in particular nozzles 26, of at least one and more preferably several and even more preferably each print head 03; 07; 27 checked for their function. In the at least one function test process, a function test is preferably carried out for each ejection opening 26, in particular each nozzle 26, in particular by checking whether a respective dot was generated and more preferably in what size and/or in which position. At least one function measurement result is preferably determined by the function test process. The respective function test process includes, for example, for the relevant component, the respective part of the test printing process, the detection process and the evaluation process and, if applicable, the assignment process.

In an alternative or additional development, the method is preferably characterized in that at least one position check process is carried out and/or that preferably exactly one position check process per print head 03; 07; 27 and/or per row of printheads. In the at least one position checking process, a relative position of at least one of the at least one print head 03; 07; 27 is checked for at least one reference, in particular at least one reference point, and/or a relative position of at least two of the at least two print heads 03; 07; 27 generated sub-images 54 to one another and/or a relative position of these at least two sub-images 54 to at least one reference, in particular at least one reference point, is checked. At least one position measurement result is preferably determined by the position checking process.

In an alternative or additional development, the method is preferably characterized in that at least one color density check process is carried out and/or that preferably exactly one color density check process per print head 03; 07; 27 and/or per row of printheads. In the color density checking process, at least one first color density measured at a first location 52, in particular of proof print image 47, and at least one additional color density are preferably compared with one another using the data recorded by sensor device 63 for this at least one proof image 47. The at least one additional color density is preferably at least one target color density and/or at least one second color density measured at a second point 53, in particular on the proof print image 47, that is spaced apart from the first point 52 in the transverse direction A oriented orthogonally to a transport direction T. At least one color density measurement result is preferably determined by the color density check process. The at least one target color density is preferably specified in advance.

In an alternative or additional development, the method is preferably characterized in that at least one color density test process and/or at least one position test process is carried out in addition to the at least one function test process. More preferably, this additional at least one color density check procedure in addition to the at least one function check procedure and/or this additional at least one position check procedure in addition to the at least one function check procedure is also carried out using, in particular, the same test print image 47 captured by the same sensor device 63. In this way, only one measurement has to be carried out and the measured result can be analyzed several times in different ways in order to generate a particularly good print image overall, with the combination of the individual improvements making it possible to achieve an even better print quality overall.

In an alternative or additional development, the method is preferably characterized in that, depending on a result of the functional test process, in particular depending on the functional measurement result, at least one control of the printing press 01 is carried out, for example manually and preferably automatically, in particular in the form of a control and /or by means of at least one computing device of the printing press 01 and/or by means of a machine controller of the printing press 01. This change is preferably made by means of a component of the printing press 01. For example, in the event that it is established that a pixel was not generated or was generated incorrectly, a corresponding ejection opening 26, in particular a corresponding nozzle 26, is cleaned, in particular as described above.

In an alternative or additional development, the method is preferably characterized in that at least one setting and/or control of printing press 01 is changed, for example manually and preferably automatically, as a function of a result of the ink density check process, in particular as a function of the color density measurement result , in particular in the form of a controller and/or by means of at least one computing device of the printing press 01 and/or by means of a machine controller of the printing press 01.

The test print image 47 preferably has at least one functional test area 48 . A representation of the at least one functional testing area 48 is preferably evaluated for functional testing of the ejection openings 26, in particular in the functional testing process. The test print image 47 preferably has at least two different areas 48; 49; 51 and more preferably at least three different areas 48; 49; 51 on. For example, area 49 is a position check area 49, the display of which is used in particular in the position check process for checking the relative position of the at least one of the at least one print head 03; 07; 27 generated partial image 54 is evaluated for at least one reference. For example, an area 51 is a color density check area 51, the representation of which is evaluated in order to compare the respective color densities, in particular in the color density check process.

The function test area 48 preferably has a large number of function test elements 57, which are arranged on the at least one substrate 02 in the form of a test matrix made up of test rows 59 and test columns 61. Such function test elements 57 are embodied, for example, as respective lines 57, in particular as straight lines 57 and/or as lines 57 aligned in transport direction T of the at least one substrate 02 and/or as lines 57, which are each produced by means of a single respective ejection opening 26 and /or were. These lines 57 therefore preferably extend in the transport direction T of the respective at least one substrate 02. The functional testing area 48 can also have further elements have elements 64, for example separating elements 64, which serve to better distinguish the function test elements 57 from one another. Such additional elements 64 or separating elements 64 are designed, for example, as lines 64 that extend in the transverse direction A and preferably delimit neighboring function test elements 57 in the transport direction T from one another. The at least one and in particular the at least two print heads 03; 07; 27 each preferably have a large number of ejection openings 26, which are formed in the form of a respective ejection matrix 43 made up of ejection rows 44 and ejection columns 46 on the respective print head 03; 07; 27 are arranged. Each ejection matrix 43 is preferably a nozzle matrix 43. Each ejection row 44 is preferably a nozzle row 44. Each ejection column 46 is preferably a nozzle column 46.

For a particularly first plurality of function test elements 572 within the test matrix 58, the following preferably applies: in the direction of the test lines 59, pairs of function test elements 57, in particular directly adjacent, of ejection openings 26 of the same print head 03; 07; 27 originating in the direction of the ejection lines 44 in the respective print head 03; 07; 27, in particular in the respective print head 03; 07; 27 of the at least two print heads 03; 07; 27 are arranged in pairs, in particular directly adjacent, and that for an in particular second plurality of function test elements 57 within the test matrix 58, in the direction of the test columns 61, in pairs, in particular directly adjacent function test elements 57 of ejection openings 26 of the same print head 03; 07; 27 originating in the direction of the ejection columns 46 in the respective print head 03; 07; 27 are arranged in pairs, in particular directly adjacent. The in particular first plurality of function test elements 572 within test matrix 58 is preferably to be understood as meaning a set of function test elements 57 within test matrix 58 that make up at least 50%, more preferably at least 75%, even more preferably at least 85%, even more preferably at least 95 % and even more preferably all of the function test elements 57 within the test matrix 58. In particular, the second plurality of function test elements 57 within test matrix 58 is preferably to be understood as meaning a set of function test elements 57 within test matrix 58 that make up at least 50%, more preferably at least 75%, even more preferably at least 85%, even more preferably at least 95% % and even more preferably all of the function test elements 57 within the test matrix 58. For example, the first plurality of function check elements 57 is identical to the second plurality of function check elements 57 .

For example, neither the ejection rows 44 nor the ejection columns 46 are arranged oriented parallel to the transverse direction A or the transport direction T. For example, the test lines 59 are arranged oriented parallel to the transverse direction A. For example, the test gaps 61 are oriented in a direction that has an angle to the transport direction T of the substrate 02 that is greater than 0° and less than 45°, more preferably less than 20°, even more preferably less than 10 °, even more preferably less than 5° and even more preferably less than 2°. This direction results, for example, from the length of the function test elements 57 parallel to the transport direction A and the distance between two adjacent ejection openings 26 arranged within the same ejection column 46.

The test matrix 58 preferably has at least three test lines 59. The check matrix 58 more preferably has at least 5 check lines 59, even more preferably at least 10 check lines 59 and even more preferably at least 20 check lines 59. For example, the test matrix 58 has at least 32 test lines 59. The check matrix 58 preferably has at least 10 check columns 61 . The check matrix 58 more preferably has at least 20 check columns 61 and even more preferably at least 40 check columns 61 .

For example, the test matrix 58 has at least 64 test columns 61 . The ejection matrix 43 of a respective print head 03; 07; 27 preferably has at least three ejection lines 44. The ejection matrix 43 of a respective print head 03; 07; 27 more preferably has at least 5 ejection lines 44, even more preferably at least 10 ejection lines 44 and even more preferably at least 20 ejection lines 44. For example, the ejection matrix 43 of a respective print head 03; 07; 27 has at least 32 ejection lines 44. The ejection matrix 43 of a respective print head 03; 07; 27 preferably has at least 10 ejection columns 46. The ejection matrix 43 of a respective print head 03; 07; 27 more preferably has at least 20 ejection columns 46 and even more preferably at least 40 ejection columns 46. For example, the ejection matrix 43 of a respective print head 03; 07; 27 at least 64 ejection columns 46. The test matrix 58 preferably has as many test lines 59 as the ejection matrix 43 has ejection lines 44 . The test matrix 58 preferably has as many test columns 61 as the ejection matrix 43 has ejection columns 46 .

The at least one print head 03; 07; 27 preferably has a large number of ejection openings 26, which are formed in the form of a respective ejection matrix 43 made up of ejection rows 44 and ejection columns 46 on the at least one print head 03; 07; 27 arranged are net. Ejection openings 26 are, for example, nozzles 26, in particular those for ejecting application fluid, in particular ink.

It preferably applies to a plurality of function test elements 57 within the test matrix 58 that function test elements 57 which are next neighbors in pairs in relation to the transverse direction A are not next neighbors in relation to absolute distances within the test matrix 58 . (This is also shown in the exemplary representation in 26 recognizable, which shows an illustration that is not true to scale.) In this way, the arrangement of the ejection openings 26, in particular nozzles 26 of the corresponding print head 03; 07; 27 adjusted. Such is an example in 25 shown.

By arranging a plurality of ejection lines 44 offset in relation to one another in the transverse direction A, the resolution of the print head 03; 07; 27 compared to a single ejection line 44 increase. In an alternative or additional development, the method and/or the test print image 47 is preferably characterized in that, for this plurality of function test elements 57 within the test matrix 58, it applies that, with respect to the transverse direction A, between such function test elements 57 that are in pairs with respect to the transverse direction A Neighbors within the same test line 59 are, viewed in absolute terms, there is a number of function test elements 57 which corresponds to the number of test lines 59 of the test matrix 58 reduced by 1 one.

In an alternative or additional development, the method and/or the test print image 47 is preferably characterized in that, for this plurality of function test elements 57, three function test elements 57 are arranged between pairs of function test elements 57 in relation to the transverse direction A, with the function test elements 57 of these pairs are arranged in the same test column 61 and at the same time in adjacent test rows 59 . This results, for example, from how the ejection openings 26 are arranged within the ejection matrix 43 and in particular from the geometric relationships such as the angle, the ejection columns 46 and/or ejection lines 44 and/or the transverse direction A with one another. When the ejection gaps 46 are slightly inclined relative to the transport direction T, fewer ejection gaps 46 overlap than when there is a large inclination.

In an alternative or additional development, the method and/or the test print image 47 is preferably characterized in that the function test elements 572 are embodied as respective lines 57 and/or are embodied as respective straight lines 57 and/or in the transport direction T of the at least one Lines 57 arranged in an aligned manner on substrate 02 are formed and/or are and/or were each produced by means of a single respective ejection opening 26.

The test print image 47 preferably has at least one position test area 49. Position checking area 49 preferably has for at least one and/or for at least two and/or for each print head 03; 07; 27 at least one position test form 54. Each position test form 54 preferably has at least two position indicator elements 62 arranged at a predetermined distance from one another. A relative target position of the position indicator elements 62 of a respective position test form 54 is preferably known in advance. More preferably, the relative actual position of the position indicator elements 62 of a respective position test form 54 is checked and, in particular, compared with the relative desired position. A relative target position of position indicator elements 62 of different position checking forms 54 is preferably known in advance. More preferably, the relative actual position of the position indicator elements 62 of different position checking forms 54 is checked and, in particular, compared with the relative target position. The at least two position indication elements 62 preferably each extend in at least two different directions, which are more preferably oriented orthogonally to one another. One of these directions is, for example, the transverse direction A. One of these directions is, for example, the transport direction T of the at least one substrate 02. For example, the at least two position test forms 54 each have at least two lines that extend in these different directions A, T and that extend beyond one another preferably cut and/or touch. The respective points of intersection and/or points of contact then preferably represent the position indication elements 62. For example, the at least two position test forms 54 each have at least two lines, which preferably extend in the transverse direction A, and at least two lines, which preferably extend in the transport direction T. For example, the at least two position test forms 54 each have at least three lines, which preferably extend in the transverse direction A, and at least five lines, which preferably extend in the transport direction T. This then preferably results in at least fifteen position indication elements 62 per position test form 54.

The test print image 47 preferably has at least one color density test area 51. The color density checking area 51 preferably has for at least one and/or for at least two and/or for each print head 03; 07; 27 each have at least one unit area 56, to which a predetermined target color density is assigned. More preferably, the color density check area 51 has for at least one and/or for at least two and/or for each printhead 03; 07; 27 each have at least two, more preferably at least four, unit areas 56, to which target color densities that differ from one another are assigned and which are arranged one behind the other, in particular in the transport direction T of the at least one substrate 02. The particularly different color densities are preferably achieved by a particularly different number of color dots per area and/or by particularly different sized ink droplets and/or by a respective particularly different area coverage. In an exemplary embodiment, the print heads 03; 07; 27 each have a plurality of print head elements, which in turn each have a plurality of ejection openings 26 . Each print head element is then preferably assigned at least one and more preferably at least two and even more preferably at least four unit areas 56, to which predetermined and/or in particular different target color densities are assigned and which are arranged one behind the other, in particular in the transport direction T of the at least one substrate 02 are. Furthermore, each print head 03; 07; 27 several unit areas 56 arranged side by side in the transverse direction A in order to be able to assess the different print head elements separately.

Reference List

01

Printing machine, inkjet printing machine, web printing machine, sheet-fed printing machine, corrugated sheet-fed printing machine

02

Substrate, web, material web, substrate web, sheet, printing material, corrugated cardboard, corrugated cardboard sheets

03

Printhead, inkjet printhead, piezo printhead

04

Inkjet printing device, inkjet printing unit

05

-

06

Printing device, application device

07

Printhead, inkjet printhead, piezo printhead, primer head, first

08

Material source, sheet feeder

09

Material source, roll unwind device, roll changer

10

-

11

drying device

12

Substrate delivery device, sheet delivery

13

substrate delivery device, winding device

14

Computer equipment, raster image processor

15

-

16

Pressure point, first

17

Pressure point, second

18

Pressure point, third

19

pressure point, fourth

20

-

21

color separation, first

22

color separation, second

23

color separation, third

24

color separation, fourth

25

-

26

Ejection port, orifice, nozzle

27

Printhead, inkjet printhead, piezo printhead, primer head, second

28

Activation element, piezo element

29

printhead assembly

30

-

31

assembly, printhead assembly

32

test section

33

Grounding spot, first

34

Grounding spot, second

35

-

36

Nozzle area (03; 07; 27)

37

computer setup

38

template image data

39

template image

40

-

41

print control data

42

print image

43

Ejection Matrix, Nozzle Matrix

44

ejection line, nozzle line

45

-

46

Ejection column, nozzle column

47

test print image

48

area, functional test area

49

area, situation check area

50

-

51

color density check area

52

digit, first

53

place, second

54

Position test form, detail

55

-

56

unit area

57

Functional test element, line

58

check matrix

59

test line

60

-

61

check column

62

location indicator element

63

Sensor device, print image sensor device, line camera

64

element, separator, line

65

-

66

test image

67

proof template

68

test sample

69

test control data

70

-

71

Mapping rule, template, digital

72

cleaning control data

73

cleaning sequence data

74

cleaning picture

75

-

76

waste section

77

Test extract, first

78

Examination extract, second

79

Examination extract, third

80

-

81

Examination extract, fourth

82

Rule, cleaning sequence, first

83

Rule, cleaning sequence, second

84

Instruction, cleaning sequence, third

85

-

86

Cleaning extract, first

87

cleaning extract, second

88

cleaning extract, third

89

cleaning extract, fourth

90

-

91

positioning device

92

cleaning device

93

feeding device

94

frame (04)

95

-

96

Cleaning template, color file, file

97

configuration file

A

transverse direction

T

transport direction

V

direction, vertical

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US10882320B2 [0005]
• WO 2019152016 A1 [0006]
• WO 2020007791 A1 [0007]

Claims (11)

Method for operating a printing machine (01), wherein the printing machine (01) has at least one print head (03; 07; 27) designed as an inkjet print head (03; 07; 27), and wherein the at least one print head (03; 07; 27) has a first set of ejection openings (26) and wherein each ejection opening (26) is assigned an activation element (28) and wherein in a proof printing process at least one proof print image (47) is generated by at least one proof section (32) of a substrate (02) relative to the at least one print head (03; 07; 27) is moved and a respective volume of the respective application fluid is ejected from a plurality of the ejection openings (26) of this first quantity, which impinges on the test section (32) of the substrate (02) and thereby contributes to the generation of the test print image (47) and wherein in a detection process the at least one printed test print image (47) is detected by means of at least one sensor device (63) and a di a virtual test image (66) is generated, and the at least one digital test image (66) is analyzed in an evaluation process and deviations from a stored test pattern (67; 68) are detected and the deviations detected are assigned to respective activation elements (28) and/or ejection openings (26), and at least one assignment rule (71) is generated in the process, and the at least one assignment rule (71) identifies faulty activation elements (28) and acceptable ones Activation elements (28) are defined and cleaning control data (72) are generated and both the at least one assignment specification (71) and cleaning sequence data (73) are used to generate the cleaning control data (72) and wherein in a first cleaning process the faulty activation elements (28 ) are operated based on the cleaning drive data (72) while acceptable activation elements (28) remain deactivated. procedure after claim 1 , characterized in that the print heads (03; 07; 27) to be cleaned are in a cleaning position during the first cleaning process, which differs from a printing position in which the print heads (03; 07; 27) to be cleaned are located during a regular printing operation. procedure after claim 1 or 2 , characterized in that a respective deviation from the stored test pattern (67; 68) means missing functional test elements (57) and/or incorrectly placed functional test elements (57) and/or functional test elements (57) printed too lightly. procedure after claim 1 or 2 or 3 , characterized in that the cleaning control data (72) are generated by superimposing the at least one assignment specification (71) with the cleaning sequence data (73). procedure after claim 1 or 2 or 3 or 4 , characterized in that the cleaning control data (72) defines those activation elements (28) which are intended to ensure that application fluid is ejected during the cleaning process. procedure after claim 1 or 2 or 3 or 4 or 5 , characterized in that a cleaning sequence (82; 83; 84) is stored by the cleaning control data (72) for each of these activation elements (28), which directly or indirectly defines their activity in the cleaning process. procedure after claim 1 or 2 or 3 or 4 or 5 or 6 , characterized in that the at least one assignment specification (71) is in the form of a text file, in particular in xml format or in txt format. procedure after claim 1 or 2 or 3 or 4 or 5 or 6 or 7 , characterized in that a cleaning template (96) designed as a file (96) is processed by a computer device (14) of the printing press (01) in order to generate the cleaning sequence data (73) and in particular that at least one raster image processor (14) is used. procedure after claim 8 , characterized in that this file (96) defines at least one image and is defined in a page description format or in a raster graphics format. procedure after claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th or 9 , characterized in that the application fluid is ejected during the cleaning process into a collecting device of a cleaning device (92) of the printing press (01). procedure after claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th or 9 or 10 , characterized in that after the first cleaning process, a test print image (42) is again generated on the substrate (02), which is then in turn detected and evaluated by the sensor device (63).

Images