Patent Publication Number: US-2023136315-A1

Title: Printing press and method for cleaning at least one nozzle bar of at least one printing unit

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is the U.S. national phase, under 35 USC § 371, of PCT/EP2020/084870, filed on Dec. 7, 2020, published as WO 2021/175468 A1 on Sep. 10, 2021, and claiming priority to DE 10 2020 105 975.2, filed Mar. 5, 2020, the disclosures of which are expressly incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     Examples herein relate to a printing press that includes at least one printing unit including at least four nozzle bars, each comprising at least one print head. At least one nozzle bar of the at least four nozzle bars includes at least one print head including at least one exit surface. The at least one printing unit includes at least two cleaning devices, and at least two nozzle bars of the at least four nozzle bars are configured to make contact in each case with at least one cleaning device of the at least two cleaning devices. At least one cleaning device of the at least two cleaning devices includes at least one cleaning element including at least one fluid supply opening. The at least one cleaning device includes at least one guide system. The at least one guide system includes at least one guide element, and the at least one cleaning device has at least one storage position and at least one usage position. In the at least one storage position, the at least one cleaning device is arranged along a transport direction of a printing substrate upstream or downstream from an area between the at least one nozzle bar and the transport path of the printing substrate. The transport direction may be determined at the position of the transport path of the printing substrate beneath the at least one nozzle bar. The at least one storage position and the at least one usage position are arranged along the at least one guide element, and the at least one storage position and the at least one usage position are spaced apart from one another at a distance of greater than zero. 
     Examples herein further relate to a method for cleaning at least one nozzle bar of at least one printing unit in which the at least one printing unit includes at least four nozzle bars, each including at least one print head. The at least one printing unit includes least four cleaning devices, with a respective cleaning device cleaning a respective nozzle bar of the at least four nozzle bars. At least one cleaning device of the at least four cleaning devices may clean at least one print head of at least one nozzle bar of the at least four nozzle bars with at least one cleaning element, which is arranged in an operating position, including at least one fluid supply opening. In at least one storage position, the at least one cleaning device is arranged along a transport direction of a printing substrate upstream or downstream from an area between the at least one nozzle bar and the transport path of the printing substrate. The transport direction may be determined at the position of the transport path of printing substrate beneath the at least one nozzle bar, and the at least one cleaning device may be moved along at least one guide element of at least one guide system from the at least one storage position into at least one usage position, or vice versa. 
     BACKGROUND 
     Various methods are available for printing onto printing substrate using a printing press, for example letterpress, gravure, or non-impact printing methods. Non-impact printing methods, for example thermographic methods or in particular the ink jet method, do not have a fixed, physically invariable printing forme and can, for example, generate different print images on a printing material during each printing operation. A non-impact printing press usually comprises at least one image-producing device, in particular at least one printing unit comprising preferably at least one print head, for example preferably an ink jet print head. In the case of the ink jet printing method, individual drops of a printing fluid are ejected as needed from at least one volume of the print head and transferred onto a printing substrate, yielding a print image on the printing substrate. By individually activating a multiplicity of volumes of the print head, different print images are generated, for example, which are individualized and/or personalized, for example, and/or are cost-effectively produced, for example, in particular in small print runs. 
     In particular in the field of application of package printing, regular cleaning of the components of the printing press, in particular of the print heads of the nozzle bars and/or the gaps thereof, is indispensable. 
     A printing press comprising a cleaning device for cleaning at least one print head of a nozzle bar is known from DE 10 2016 214 356 A1. 
     DE 11 2014 003 630 T5 discloses a cleaning device comprising a spray nozzle for spraying a cleaning solution onto a gap between two head modules of an ink jet print head and two removal elements, configured as wiping cloths, for removing the cleaning solution. 
     U.S. 2013/0106940 A1 discloses an ink jet printing press comprising an ink jet print head. The printing press comprises at least one wiping device including a wiper for cleaning an ejecting surface and a wiper for cleaning a liquid collection point. Furthermore, an annular member is disclosed, which seals a liquid ejection area with respect to its surrounding area when arranged in a capping position. 
     U.S. 2015/0158304 A1 teaches a cleaning system for cleaning an ink jet printer comprising multiple print heads. In particular poorly soluble UV-based ink is cleaned off the exit surface of the print head using a wiping device. A cover seals the nozzles of the exit surface with respect to its surrounding area. 
     WO 2019/059099 A1 discloses a printing device comprising ink jet print heads, wherein the print heads are moved horizontally from a printing position into a service position. A cleaning system comprises a wiping unit including a wiping cloth, wherein the nozzle surface is cleaned using a dry cleaning mode and a moist cleaning mode under pressure contact. In addition, sealing elements for sealing the nozzle surface are provided. 
     U.S. 2010/0214355 A1 discloses a service device for cleaning a print head of a printing press. A device for spraying cleaning liquid is used to carry out contactless cleaning of the print head. Contact cleaning is carried out by means of a device including a wiping cloth. A cap is used to cover the nozzle surface after cleaning has been carried out. The print head is moved from its printing position into a service position for cleaning. The device including a wiping cloth is moved from a non-contact position into a contact position for carrying out the contact cleaning. 
     U.S. 2012/0038707 A1 teaches a printing device comprising ink jet print heads. A print head is supported by a frame, with the frame having a printing position and a service position. The service position is shifted laterally along the axis of an impression cylinder with respect to the printing position. A device for ejecting cleaning liquid is used for cleaning with indirect contact with the nozzle surface. A device including a wiping cloth and a blade is used for cleaning with direct contact with the nozzle surface. The devices cleaning the nozzle surface are arranged between the printing position and the service position, wherein the nozzle surface is cleaned during the movement from the service position into the printing position, or vice versa. 
     DE 696 02 301 T2 discloses an ink jet printing system comprising multiple print heads in a carriage element. The carriage element moves along a print path through a print zone. A first service station for carrying out a first wiping operation at a first print head and a second service station for carrying out a second wiping operation at a second print head are positioned in the print head path. The first wiping operation employs a flexible wiper blade, while a stationary blade is used during the second wiping operation. The first and second service stations are arranged on a first side of the print zone, adjacent to one another. 
     U.S. 2014/0292911 A1 discloses an ink jet printing device comprising a service unit. The service unit comprises a unit for applying cleaning liquid onto the nozzle surface of a print head, and an absorption unit comprising a wiping element and at least one covering unit. The nozzle surface and the service device are arranged opposite one another, relative to one another, by a moving device. 
     DE 10 2016 125 321 A1 teaches a device for cleaning print heads. The device comprises at least one spray nozzle for generating a cleaning jet, and at least one wiping lip. The spray nozzle and the wiping lip are arranged on a shared carriage or on separate carriages, wherein the carriage is, or the carriages are, movably arranged on a linear guide. 
     U.S. 2019/283431 A1 discloses a cleaning device for cleaning a nozzle bar. A first cleaning element and a second cleaning element wipe the nozzle surface of the print heads. 
     EP 1 218 193 A1 teaches a service station for cleaning a print head. The assembly of the service station comprises a wiper and at least one sprayer. The service station can be arranged in the standby, wiping and sealing positions. 
     U.S. 2012/212542 A1 shows a cleaning device for cleaning print heads. The cleaning head comprises a nozzle and a drain. The cleaning device ejects liquid, which fills a clearance between the nozzle surface of the print head and the cleaning head. The cleaning device can be arranged in a cleaning position and a standby position, the standby position of the cleaning head being withdrawn to the side of the print head. U.S. 2018/207936 A1 shows a cleaning unit, which comprises a movable component comprising wipers and a frame. The cleaning unit comprises a plurality of wipers for each nozzle bar, and the four nozzle bars are cleaned jointly by means of the cleaning unit. For cleaning the nozzle bars, the cleaning unit is moved from its storage position beneath a second transport means, which is arranged downstream from the nozzle bars, into a usage position beneath the nozzle bars. 
     SUMMARY 
     It is an object of the invention to create a printing press and a method for cleaning at least one nozzle bar of at least one printing unit. 
     This object is achieved in some examples by a printing press in which at least two cleaning devices include the at least one guide system configured as a shared guide system. The at least two cleaning devices include at least one guide element configured as a shared guide element. Further, the at least one guide element may be configured as a shared guide element and may be configured as a linear guide and/or a rail. Additionally, in some examples, a method includes that at least two cleaning devices of at least four cleaning devices are jointly connected to at least one guide system, and are jointly moved by the at least one guide system from the at least one usage position into the at least one storage position, or vice versa. Further, the at least two cleaning devices may include at least one shared guide element of the at least one guide system, which is configured as a rail. 
     The dependent claims show advantageous refinements and/or embodiments of the identified solutions. 
     The advantages to be achieved with the invention are, in particular, that a printing press is created. The printing press comprises at least one printing unit including at least four nozzle bars, each including at least one print head. The at least one printing unit comprises at least one cleaning device. The at least one printing unit preferably comprises the at least one cleaning device and at least one cleaning system. The at least one cleaning device comprises at least one cleaning element including at least one fluid supply opening. The at least one cleaning system preferably comprises at least one removal unit including at least one contact element. The at least one contact element is preferably configured as a wiping cloth. The at least one removal unit preferably has at least one supply position and at least one operating position. In the at least one operating position, the at least one removal unit is preferably arranged within an area between at least one nozzle bar of the at least four nozzle bars and a transport path of a printing substrate. The at least one cleaning element preferably has at least one supply position and at least one operating position. In the at least one operating position, the at least one cleaning element is preferably arranged within the area between the at least one nozzle bar and the transport path of a printing substrate. Selectively, the at least one cleaning device and/or the at least one cleaning system are preferably arranged in the area between the at least one nozzle bar and the transport path of printing substrate. At least one nozzle bar of the at least four nozzle bars preferably has at least one printing position and at least one service position. The at least one nozzle bar is preferably selectively arranged in the printing position or in the at least one service position. The at least one service position is preferably arranged in the vertical direction, preferably in a z direction, above the printing position. The at least one cleaning device is preferably configured to clean the at least one print head, preferably at least one exit surface, in a contactless manner. In addition or as an alternative, the at least one cleaning system is preferably configured to make direct contact with the at least one print head. The at least one cleaning device has at least one storage position and at least one usage position. In the at least one storage position, the at least one cleaning device is arranged along a transport direction of printing substrate at the position of the transport path beneath the at least one nozzle bar upstream or downstream from the at least one nozzle bar. In the at least one storage position, the at least one cleaning device is arranged along an x direction, which preferably corresponds to a direction along a shortest side of the respective nozzle bar, upstream or downstream from the at least one nozzle bar. In the at least one usage position, the at least one cleaning device is preferably arranged within an area between the at least one nozzle bar and the transport path of printing substrate. 
     A method for cleaning at least one nozzle bar of at least one printing unit is created. The at least one printing unit comprises at least four nozzle bars, each comprising at least one print head. At least one print head, preferably at least one exit surface of at least one print head, of at least one nozzle bar of the at least four nozzle bars is cleaned in a contactless manner by at least one cleaning device. At least one print head, preferably at least one exit surface of at least one print head, of at least one nozzle bar of the at least four nozzle bars is preferably cleaned in a contactless manner by at least one cleaning device comprising at least one cleaning element, which is arranged in an operating position, including at least one fluid supply opening. In the operating position, the at least one cleaning element is preferably arranged within an area between the at least one nozzle bar and a transport path of printing substrate. In at least one storage position, the at least one cleaning device is arranged along a transport direction of printing substrate at the position of the transport path beneath the at least one nozzle bar upstream or downstream from the at least one nozzle bar. In at least one usage position, the at least one cleaning device is preferably arranged within an area between the at least one nozzle bar and the transport path of the at least one printing substrate. The at least one print head of the at least one nozzle bar of the at least four nozzle bars is preferably cleaned by at least one cleaning system comprising at least one removal unit, which is arranged in at least one operating position, comprising at least one contact element configured as a wiping cloth. In at least one operating position, the at least one removal unit is preferably arranged within the area between the at least one nozzle bar and the transport path of printing substrate. Preferably selectively, the at least one cleaning device and/or the at least one cleaning system clean the at least one print head of the at least one nozzle bar of the at least four nozzle bars. The at least one nozzle bar is preferably selectively arranged in a printing position or in at least one service position. The at least one nozzle bar is preferably moved in a direction having a larger vertical component and a smaller horizontal component from the printing position into the at least one service position and/or from the at least one service position into the printing position. Selectively, the at least one cleaning device and/or the at least one cleaning system are preferably displaced into an area between the at least one nozzle bar and the transport path of printing substrate. 
     The printing press comprises at least one printing unit including at least one nozzle bar, wherein the at least one printing unit comprises at least one cleaning device, the at least one nozzle bar comprising at least one print head, preferably the at least one nozzle bar having at least one printing position and at least one service position, and preferably the at least one printing unit comprising at least one cleaning system. The at least one cleaning device comprises at least one cleaning element including at least one fluid supply opening. Advantageous in addition or as an alternative, the at least one cleaning system comprises at least one removal unit including at least one contact element. Advantageously, the at least one cleaning device and/or the at least one cleaning system selectively make contact with the at least one print head. 
     The at least one printing unit advantageously comprises the at least one cleaning device and the at least one cleaning system. Advantageously, this enables optimal cleaning of the at least one nozzle bar and/or of its at least one print head of the at least one printing unit of the printing press. Advantageously, a distinction can be made between a cleaning device and a cleaning system for cleaning the at least one nozzle bar. This makes it possible to advantageously react to the respective requirements and/or in accordance with the operating states of the at least one nozzle bar that occur or are present, in particular to the duration for which the at least one nozzle bar had a printing or non-printing operating state and/or in particular will have subsequent to the cleaning process. In addition or as an alternative, it is possible to react to the degree of soiling that is present and/or to the intensity with which the at least one nozzle bar and/or its at least one print head, for example due to the printing fluid used, is to be cleaned. 
     Advantageously, a disruption of the transport of a printing substrate that is being conveyed along the transport path by the at least one cleaning device and/or the at least one cleaning system is avoided. Preferably, at least one printing substrate is conveyed along the transport path by the at least one printing unit, while at least one nozzle bar of the printing unit is being cleaned by the at least one cleaning device and/or by the at least one cleaning system. For example, this at least one printing substrate is printed by at least one further nozzle bar, for example of the at least one printing unit and/or of at least one further printing unit. Advantageously, down times of the printing press are minimized. 
     The contact between the at least one print head and the at least one cleaning device is advantageously configured to be gentle on the print head, in particular its exit surface, since in this way in particular the exit surface of the print head is advantageously arranged so as not to be in direct contact with the cleaning device, and consequently damage, in particular to the exit surface, is avoided. In particular, the at least one cleaning system is configured to make direct contact with the at least one print head. In this way, the at least one cleaning system is preferably configured to clean off heavy dirt and/or at least partially insoluble residue of printing fluid and/or to carry out a thorough cleaning of the at least one print head. Cleaning of the at least one print head using direct contact with the at least one contact element advantageously removes dirt and/or printing fluid that, for example, was not removed by the cleaning operation by way of the at least one cleaning element and/or that, for example, has completely dried. 
     In particular a combination of cleaning by way of at least one cleaning element of the cleaning device and at least one contact unit of the cleaning system advantageously completely removes dirt and/or printing fluid from the at least one print head of the at least one nozzle bar and/or from a positioning gap between two adjacent print heads. 
     The at least one cleaning device comprises at least one guide system. The at least one guide system comprises at least one guide element. The at least one cleaning device is configured to move and/or be movable and/or is moved along the at least one guide element of the at least one guide system from the at least one storage position into the at least one usage position, or vice versa. Advantageously, the at least one guide element enables rapid and secure guidance of the at least one cleaning device. The risk of the cleaning device tilting and, for example, thereby damaging the at least one exit surface, is minimized. 
     At least two cleaning devices comprise a shared guide system, at least one shared guide element of the guide system. In this way, the at least two cleaning devices are configured to be movable and/or to move jointly, in particular from the at least one storage position into the at least one usage position, or vice versa. This advantageously results in a space-saving design of the at least one guide system and/or in easy handling of the at least two cleaning devices. Advantageously, the at least two cleaning devices, as a result of the advantageous design of the at least one guide system, are configured to move into or out of an area between the at least one nozzle bar and a transport path of at least one printing substrate, in particular without, for example, interrupting and/or influencing a movement of a printing substrate moving along the transport path. Advantageously, the at least two cleaning devices are arranged so as to be aligned with respect to the at least one nozzle bar, regardless of their position, for example as a result of being inclined with respect to the z direction, and are advantageously configured to be movable and/or to move in the aligned arrangement. Advantageously, the at least two cleaning devices comprise at least two shared guide systems. In particular, this prevents the cleaning devices from tilting along the working width of the printing unit and additionally establishes, or alternatively fixes, the printing unit across the working width the positioning and/or the aligned arrangement of the at least two cleaning devices. Advantageously, multiple rows of print heads are thus cleaned simultaneously, for example. Advantageously, a cost-effective guide system is created. 
     Advantageously, the at least one cleaning system is configured to move and/or be movable along at least one guide element. In an advantageous embodiment, at least two removal units of the at least one cleaning system are configured to move and/or be movable along the at least one guide element. The advantageous embodiment of the at least one guide element results in space savings within the printing unit. 
     Advantageously, the printing unit comprises the at least one sealing element. Advantageously, the at least one sealing element is configured in particular to protect the at least one print head, preferably the at least two print heads, of the at least one nozzle bar. In this way, printing fluid is advantageously conserved in the at least two print heads, in particular by the at least one sealing element, and/or is protected against drying out and/or is prevented from clogging at least one nozzle of the exit surface of the print head. Advantageously, the at least one sealing element is arranged to be in contact with the at least two print heads when the at least one nozzle bar is in a service position, but is arranged within the printing unit. In this way, the print heads advantageously remain in the printing unit or in their position in the nozzle bar. Advantageously, in this way an alignment of the print heads is dispensed with before these are being arranged and/or are arranged in at least one printing position again, after having made contact with the at least one sealing element. In particular, it is advantageously possible to arrange at least one nozzle bar of the printing unit in the printing position or in at least one service position and/or at least one nozzle bar of the printing unit is arranged in the printing position or in the at least one service position when at least one nozzle bar different therefrom, in particular at least two print heads of the nozzle bar different therefrom, are in contact with the at least one sealing element. The nozzle bar that is arranged in the at least one service position, which is not in contact with the at least one sealing element, is advantageously cleaned in the at least one service position by a cleaning device and/or a cleaning system, and/or advantageously another service operation, such as a replacement of print heads, is carried out. In an advantageous embodiment, the at least one cleaning device comprises the at least one sealing element. Advantageously, the at least one sealing element is then configured to be movable and/or to move by way of at least one guide system of the cleaning device, which, for example, results in space savings and/or easier handling within the printing unit. 
     Another advantage is that the at least one removal unit of the at least one cleaning system is configured to clean the at least one print head of the at least one nozzle bar. The at least one removal unit is advantageously configured to clean at least two print heads arranged in a row, in particular consecutively, along the longest side of the at least one nozzle bar, in particular by way of a displacement along the guide element. Advantageously in addition or as an alternative, the at least one removal unit is arranged in at least one supply position or at least one operating position as a result of the displacement along the at least one guide element. In particular, the at least one removal unit remains within the printing unit, regardless of its position. By arranging at least two removal units on at least one shared carrier, advantageously at least two rows of print heads can be cleaned and/or are cleaned, in particular simultaneously. This, for example, results in time savings of the cleaning step as well as, in addition or as an alternative, in space savings, in particular since no guide elements of the individual removal units are required. In an advantageous embodiment, a driven storage device of the contact element, or a storage device connected to a drive, which is advantageously configured as a wiping cloth, makes it possible for the contact between a contact element that is used in a cleaning step and the at least one print head to be dissolved, and for a contact element that has not yet been used in a cleaning step and/or is clean to make contact with the at least one print head. The advantageous embodiment of the at least one pressing element advantageously ensures that the at least one contact element is gently brought in contact with the at least one print head. In particular, the resilient design and/or the setting of the contact pressure protects the at least one print head, in particular its exit surface, against damage. In particular, it is ensured that the at least one contact element is optimally set against the at least one print head, and thus is optimally cleaned, as a result of an inclination of the removal unit corresponding to the inclination of the print head. 
     Further advantages are apparent from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are illustrated in the drawings and will be described in greater detail below. The drawings show: 
         FIG.  1    a schematic perspective illustration of at least one printing unit comprising at least one nozzle bar and at least one opposite printing substrate guide element as well as a printing substrate; 
         FIG.  2   a    shows a schematic illustration of at least one nozzle bar comprising two rows of diagonally overlapping print heads; 
         FIG.  2   b    shows a schematic illustration of an alternative embodiment of at least one nozzle bar comprising multiple print heads, which are arranged offset from one another in a double row; 
         FIG.  3   a    shows a schematic perspective illustration of at least two print heads, which are arranged spaced apart from one another by a positioning gap, comprising at least one first feed device, which is assigned to the positioning gap, and a second feed device, the second feed device being illustrated in a sectional view; 
         FIG.  3   b    shows a schematic breakdown of an exemplary feed device; 
         FIG.  4   a    shows a schematic illustration of a printing unit comprising multiple nozzle bars, at least one nozzle bar being arranged in a printing position and at least one nozzle bar is arranged in an idle position; 
         FIG.  4   b    shows a schematic illustration of a printing unit comprising multiple nozzle bars according to  FIG.  4   a   , at least one nozzle bar being arranged in a first service position; 
         FIG.  4   c    shows an exemplary illustration of a printing unit comprising four nozzle bars arranged in the first service position and four cleaning devices arranged in a usage position; 
         FIG.  4   d    shows a schematic illustration including two nozzle bars arranged in the printing position, and in each case two cleaning devices arranged on a shared guide system in a storage position; 
         FIG.  4   e    shows an exemplary illustration of four nozzle bars arranged in the idle position and four cleaning devices and one cleaning system; 
         FIG.  4   f    shows a schematic illustration of four nozzle bars arranged in the idle position, and four cleaning devices arranged in the storage position, and one cleaning system comprising removal units arranged in an operating position; 
         FIG.  4   g    shows a schematic illustration of four nozzle bars arranged in a second service position and four cleaning devices arranged in the storage position, and one cleaning system comprising removal units arranged in an operating position; 
         FIG.  4   h    shows an exemplary illustration of four nozzle bars arranged in a second service position, and four cleaning devices arranged in the storage position, and one cleaning system comprising removal units arranged in an operating position; 
         FIG.  5   a    shows a view of at least four print heads within a row of one nozzle bar and a cleaning device, at least one cleaning element being arranged opposite at least one print head and being in direct or indirect contact therewith, for the sake of clarity only four print heads being shown; 
         FIG.  5   b    shows a sectional illustration of the print heads of the nozzle bar and of the cleaning device according to a section along line V-V in  FIG.  5     a;    
         FIG.  6   a    shows an illustration of a cleaning element; 
         FIG.  6   b    shows an illustration of the cleaning element according to  FIG.  6   a    in a perspective view; 
         FIG.  6   c    shows an illustration of an alternative cleaning element in a perspective view; 
         FIG.  7   a    shows an illustration of a further alternative embodiment of a cleaning element; 
         FIG.  7   b    shows an illustration of the further alternative embodiment of a cleaning element according to  FIG.  7   a    in a perspective view; 
         FIG.  7   c    shows an illustration of the further alternative embodiment of a cleaning element according to  FIG.  7   a    and/or  FIG.  7   b   , comprising at least one additional wiper; 
         FIG.  7   d    shows an arrangement of a cleaning element including four cleaning areas at a nozzle bar including four rows of print heads; 
         FIG.  8   a    shows an exemplary illustration of a nozzle bar including two rows of print heads in contact with at least one cleaning element of the at least one cleaning device; 
         FIG.  8   b    shows an exemplary illustration of a nozzle bar including two rows of print heads in contact in each case with at least one sealing element; 
         FIG.  9    shows a first embodiment of a printing unit comprising a cylindrical printing substrate guide element, two cleaning devices in each case comprising a shared guide system; 
         FIG.  10    shows another exemplary embodiment of a printing unit comprising a cylindrical printing substrate guide element, two cleaning devices in each case comprising a shared guide system, and the printing unit, in addition to the cleaning device, comprising a cleaning system comprising at least two removal units; 
         FIG.  11    shows the further exemplary embodiment of a printing unit comprising a cylindrical printing substrate guide element from  FIG.  10    in a side view; 
         FIG.  12   a    shows an exemplary illustration of a cleaning system comprising removal units, arranged in the supply position, in the case of a printing unit comprising a cylindrical printing substrate guide element; 
         FIG.  12   b    shows an exemplary illustration of the cleaning system from  FIG.  12   a   , comprising removal units arranged in the at least one operating position; 
         FIG.  13   a    shows an exemplary removal unit in a three-dimensional illustration, comprising a reservoir of contact element arranged in a housing; 
         FIG.  13   b    shows an exemplary removal unit from  FIG.  13   a    in a lateral sectional view; 
         FIG.  13   c    shows an exemplary removal unit from  FIG.  13   a    and  FIG.  13   b    in another lateral sectional view; 
         FIG.  13   d    shows an exemplary removal unit from  FIG.  13   a    to  FIG.  13   c    in a three-dimensional illustration, with the reservoir being opened; 
         FIG.  14    shows multiple exemplary removal units on a shared carrier; 
         FIG.  15    shows an alternative exemplary cleaning system, comprising two removal units arranged horizontally next to one another, in the case of a printing unit having a linear transport path in the x direction; 
         FIG.  16   a    shows another alternative embodiment of a printing unit having a linear transport path in the x direction, the printing unit comprising at least one cleaning device in a storage position and at least one cleaning system operating position; 
         FIG.  16   b    shows another illustration of the printing unit having a linear transport path in the x direction from  FIG.  16   a   , the nozzle bar being hidden; 
         FIG.  16   c    shows another illustration of the printing unit having a linear transport path in the x direction from  FIG.  16   a    or  FIG.  16   b   , the cleaning system being pivoted into its supply position, and the cleaning device being arranged in its storage position; 
         FIG.  16   d    shows another illustration of the printing unit having a linear transport path in the x direction from  FIG.  16   a   ,  FIG.  16   b    or  FIG.  16   c   , the cleaning system being pivoted into its supply position, and the cleaning device being arranged in its usage position; 
         FIG.  17   a    shows a side view of the printing unit having a linear transport path in the x direction corresponding to  FIG.  16   a    or  FIG.  16   b   , the cleaning system being arranged in the operating position, and the cleaning device being arranged in the storage position; 
         FIG.  17   b    shows a side view of the printing unit having a linear transport path in the x direction corresponding to  FIG.  16   c   , the cleaning system being pivoted into its supply position, and the cleaning device being arranged in its storage position; 
         FIG.  17   c    shows a side view of the printing unit having a linear transport path in the x direction corresponding to  FIG.  16   d   , the cleaning system being pivoted into its supply position, and the cleaning device being arranged in its usage position. 
     
    
    
     DETAILED DESCRIPTION 
     A printing press comprises at least one printing unit  01  and at least one printing substrate guide element  02  for guiding at least one printing substrate  03 . The at least one printing unit  01 , which is in particular configured as a non-impact printing unit  01 , preferably as an ink jet printing unit  01 , comprises at least one nozzle bar  04 , comprising at least one print head  08 , preferably at least one ink jet print head  08 , more preferably a print head  08  operating according to the piezo ink jet method. Preferably, at least one printing substrate guide element  02  is assigned to the relevant nozzle bar  04 . The at least one print head  08  comprises at least one exit surface  09 . In the case of the piezo ink jet method, a formation and an ejection of drops of the print head  08  preferably take place by way of mechanical deformation of at least one nozzle chamber of the print head  08 , in particular as a result of an electronic signal and the piezoelectric properties of the material of the nozzle chamber. For example, the printing press comprises at least two printing units  01 , each comprising at least one, preferably at least two, more preferably at least four, nozzle bars  04 . For example, at least eight different colors can thus be printed and/or the printing substrate  03  can be printed both on the upper side and on the underside. 
     The printing press, within this patent specification, is a machine that applies and/or is capable of applying at least one printing fluid onto at least one printing substrate  03 . 
     Above and below, the at least one printing substrate  03  is a substrate onto which a medium, in particular a printing fluid, can be printed by the at least one printing unit  01 . Preferably, the printing substrate  03  is preferably configured as paper and/or cardboard and/or corrugated cardboard and/or paperboard. The printing substrate  03  is in particular configured as a web or a sheet. 
     According to DIN 6730, paper is a flat material, consisting mainly of fibers derived from vegetable sources, which is formed by the dewatering of a fiber suspension on a sieve. In the process, a card web is created, which is subsequently dried. The basis weight of paper is preferably a maximum of 225 g/m 2 . According to DIN 6730, cardboard is a flat material, consisting mainly of fibers derived from vegetable sources, which is formed by the dewatering of a fiber suspension on a sieve or between two sieves. The fiber structure is compressed and dried. Cardboard is preferably manufactured from cellulose by gluing or pressing the cellulose together. Cardboard is preferably configured as solid board or corrugated cardboard. The basis weight of cardboard is preferably more than 225 g/m 2 . Corrugated cardboard is cardboard made of one or more layers of corrugated paper that is glued to one layer or between multiple layers of another, preferably smooth, paper or cardboard. Above and below, the term paperboard preferably refers to a sheet material that is preferably primed on one side and made of paper, having a basis weight of at least 150 g/m 2  and no more than 600 g/m 2 . Paperboard preferably has high strength relative to paper. 
     Preferably, the at least one printing substrate  03 , for example at least a portion of the at least one printing substrate  03 , is configured as an intermediate product for producing an end product, and/or is, for example, further processed and/or is configured to be further processable into a desired or required end product. For example, the at least one printing substrate  03  is configured as paper and is further processed to corrugated cardboard. The desired or required end product, which was preferably generated by further processing at least part of the printing substrate  03 , is preferably a packaging material, and more preferably at least one folding box. 
     The at least one printing substrate  03  preferably includes at least one pigment coating. The at least one printing substrate  03  preferably includes a pigment coating of at least 5%, preferably at least 8%, more preferably at least 10%, of the total weight of the at least one printing substrate  03 . In addition or as an alternative, the at least one printing substrate  03  includes a pigment coating of no more than 30%, preferably no more than 25%, more preferably no more than 20%, of the total weight of the at least one printing substrate  03 . Above and below, a pigment coating preferably denotes a coating material that is applied to the surface of the at least one printing substrate  03 . The printing substrate  03  comprising at least one coating material is preferably referred to as a coated printing substrate  03 . The surface of the printing substrate  03  is preferably at least partially finished by the application of the at least one coating material. Compared to an uncoated printing substrate  03  having no coating material applied thereto, a coated printing substrate  03  preferably has improved printability and/or a smoother surface, and/or accepts printing fluid in a way that is adapted to the required print image. The at least one coating material preferably comprises at least one binding agent and/or at least one additive and/or at least one pigment. 
     Preferably, the at least one printing substrate  03  has a total weight, that is, preferably including the at least one pigment coating, of at least 120 g/m 2  (one hundred twenty grams per square meter), preferably of at least 130 g/m 2  (one hundred thirty grams per square meter), more preferably of at least 145 g/m 2  (one hundred forty-five grams per square meter), and, additionally or alternatively, a total weight of no more than 260 g/m 2  (two hundred sixty grams per square meter), preferably of no more than 240 g/m 2  (two hundred forty grams per square meter), more preferably of no more than 230 g/m 2  (two hundred thirty grams per square meter). Preferably in addition or as an alternative, the at least one printing substrate  03  has a thickness of at least 120 μm (one hundred twenty micrometers), preferably at least 140 μm (one hundred forty micrometers), more preferably 160 μm (one hundred sixty micrometers), and, additionally or alternatively, a thickness of no more than 300 μm (three hundred micrometers), preferably no more than 280 μm (two hundred eighty micrometers), more preferably no more than 260 μm (two hundred sixty micrometers). 
     Preferably, the at least one nozzle bar  04  in each case comprises at least two print heads  08 , which are arranged next to one another in a y direction, in particular abutting one another, preferably adjacent to one another, and/or which extend in particular across the entire working width of the printing unit  01 . Preferably, the number of print heads  08  arranged along the longest side of the nozzle bar  04  in the nozzle bar  04  is such that an entire working width of the printing unit  01  and/or of the nozzle bar  04  and/or of the printing press is covered in each case by at least one print head  08 . The at least one nozzle bar  04  preferably extends across the entire working width of the printing unit  01  and/or of the printing press. The respective print heads  08  of a nozzle bar  04  are preferably in each case arranged, in the y direction, in at least one row, preferably in at least two rows, for example in exactly two rows. The at least one nozzle bar  04  preferably comprises the at least two rows of in each case at least two print heads  08  that are arranged next to one another. The at least one nozzle bar  04  preferably extends across the entire working width of the printing unit  01 . In particular, for example, at least two print heads  08  of the nozzle bar  04  are in each case arranged next to one another in a y direction and/or connected to one another via a for example fixed axis in the y direction to form a group of print heads  08 . The at least one nozzle bar  04  preferably has a longitudinal extension in the y direction. The at least one nozzle bar  04  preferably has an extension along its width in the x direction. The longitudinal extension is preferably greater than the extension in the width. The longitudinal extension preferably includes a larger number of print heads  08  than the extension in the direction of the width. 
     The y direction and an x direction and a z direction form a Cartesian coordinate system. The x direction preferably corresponds to a direction along a shortest side of the respective nozzle bar  04 . The y direction preferably corresponds to a direction along a longest side of the respective nozzle bar  04 . The y direction is preferably parallel to an axis of rotation of the at least one printing substrate guide element  02 . The x direction and the y direction preferably span a horizontal plane. The longest side of the at least one nozzle bar  04  is preferably the side of the at least one nozzle bar  04  along which at least two, preferably at least four, more preferably at least eight, print heads  08  are arranged in a row. Preferably, the at least one row of print heads  08  extends, preferably at least two rows of print heads  08  extend, along the longest side of the at least one nozzle bar  04 . The shortest side of the at least one nozzle bar  04  is preferably arranged orthogonally to its longest side. Preferably, only one print head  08  of a respective row is arranged along the shortest side of the at least one nozzle bar  04 . For example, two print heads  08  of a respective row of print heads  08  are arranged one behind the other along the shortest side of the at least one nozzle bar. The z direction is preferably parallel to a normal vector of a plane spanned by the x direction and the y direction. The z direction preferably corresponds to a vertical direction. 
     A transverse direction A is preferably a direction that extends in each case parallel to a longest side of the at least one nozzle bar  04 . The transverse direction A is preferably situated parallel to the y direction. The x direction is preferably situated orthogonally to the transverse direction A. The working width is in particular parallel to the transverse direction A. Furthermore, the transverse direction A is preferably orthogonal to a transverse direction T. 
     Above and below, the working width is the maximum width that a printing substrate  03  is allowed to have to be able to still be processed by the at least one printing unit  01  of the printing press, which thus corresponds to the maximum width of the respective printing substrate  03  that can be processed by the at least one printing unit  01  of the printing press. The working width preferably corresponds to an extension of the at least one exit surface  09  of at least one print head  08  along the y direction which is preferably utilized for printing onto the printing substrate  03 . 
     The spatial area intended for transporting a printing substrate  03 , which the printing substrate  03 , if present, at least temporarily occupies, is the transport path. The transport path is established by at least one transport means, in particular by the at least one printing substrate guide element  02 . Preferably, the at least one printing substrate guide element  02  is in each case configured as at least one roller and/or at least one cylinder and/or at least one supporting surface and/or at least one other device for guiding the printing substrate  03  in a printing operating mode of the printing press. 
     The transport direction T is a direction T which is intended for a printing operating mode of at least one printing unit  01  of the printing press and in which the printing substrate  03 , if present, is transported at each point of the transport path. The transport direction T is preferably a direction that extends in each case parallel to a shortest side of the at least one nozzle bar  04 . The transverse direction A is the axial direction orthogonal to the transport direction T. Preferably, for example, the transport direction T is parallel to the x direction and/or, for example, the transverse direction A is parallel to the y direction of the Cartesian coordinate system at a point of the shortest distance between a relevant print head  08  and the transport path. 
     Above and below, a printing fluid refers to inks, printing colors and/or varnishes, as well as further materials that are transferred and/or can be transferred by a printing press or at least one printing unit  01  of the printing press onto a printing substrate  03 . A printing fluid that is present in a volume of the print head  08  can preferably exit the volume of the relevant print head  08  through an opening in the exit surface  09 , in particular in the form of drops. The at least one nozzle bar  04  preferably includes cyan (C) or magenta (M) or yellow (Y) or black (K) as colors of the printing fluid. Preferably, two different nozzle bars  04  include different printing fluids. Preferably, in each case at least one nozzle bar  04 , preferably in each case at least one nozzle bar  04  of the at least four nozzle bars  04 , of the printing press or of the at least one printing unit  01  includes cyan (C) or magenta (M) or yellow (Y) or black (K) as colors of the printing fluid. For example, at least one nozzle bar  04  includes a further printing fluid, which is embodied as a varnish or primer, for example. The at least four nozzle bars  04  of the printing unit  01  preferably include different colors. 
     The printing fluid of the at least one print head  08  is preferably embodied as printing fluid for package printing and/or for printing a packaging material. Preferably, the at least one nozzle bar  04 , in particular the at least one print head  08 , includes printing fluid having a viscosity, preferably a dynamic viscosity, of at least 3 mPa*s (three millipascal seconds), preferably at least 4.5 mPa*S (four point five millipascal seconds), and/or having a viscosity of no more than 6 mPa*s (six millipascal seconds), preferably no more than 5.5 mPa*s (five point five millipascal seconds). The preceding viscosity values preferably refer to the viscosity between 20° C. (twenty degrees Celsius) and 40° C. (forty degrees Celsius), preferably of at least 25° C. (twenty-five degrees Celsius) and/or no more than 35° C. (thirty-five degrees Celsius), and/or were preferably determined according to DIN EN ISO 2884-1:2006-09. The printing fluid is preferably water-based and/or at least partially water-soluble and/or preferably includes at least one pigment. Preferably, the at least one nozzle bar  04  includes printing fluid having a pigment content of the printing fluid of at least 1%, preferably of at least 2%, more preferably of at least 3%, more preferably of at least 4%, and/or preferably having a pigment content of the printing fluid of no more than 18%, preferably of no more than 14%, more preferably of no more than 10%, more preferably of no more than 7%. For example, the fully dried printing fluid is more difficult to dissolve using cleaning agent than printing fluid having a residual content of liquid printing fluid. 
     Above and below, a cleaning agent and/or cleaning fluid in particular denotes a liquid that is employed when cleaning individual components of a printing press, in particular for cleaning at least one exit surface  09  of at least one print head  08 . The cleaning agent is preferably employed for removing residues of the at least one printing fluid on components of the printing press, in particular of the exit surface  09  of at least one print head  08  and/or of a positioning gap  07  between two print heads  08  that are arranged next to one another. For example, the cleaning agent comprises water and/or at least one surfactant and/or at least one solvent. For example, the at least one cleaning fluid comprises printing fluid that preferably does not include any pigments. The at least one cleaning fluid is preferably configured to at least partially dissolve the printing fluid of the at least one nozzle bar  04 . 
     A printing unit  01  comprises at least one nozzle bar  04 . A printing unit  01  comprises at least four nozzle bars  04 , for example exactly four nozzle bars  04 . The at least one nozzle bar  04  is, for example, arranged in at least one printing position, for example shown in  FIG.  1   . The printing position describes the position of the nozzle bar  04  in which the nozzle bar  04  is arranged in a printing operating mode of the printing press. Printing fluid is preferably printed onto least one printing substrate  03  in the printing operating mode by the at least one print head  08  of the at least one nozzle bar  04  that is arranged in the printing position, preferably of the at least one nozzle bar  04  of the at least four nozzle bars  04 . Preferably, a respective print head  08  that is arranged in its printing position is characterized in that the respective exit surface  09  has a distance, with respect to the intended transport path for at least one printing substrate  03  and/or with respect to the at least one printing substrate  03  and/or with respect to the printing substrate guide element  02  assigned to the respective nozzle bar  04 , which is no more than 5 mm (five millimeters), preferably no more than 1.5 mm (one point five millimeters) and/or which is at least 0.5 mm (zero point five millimeters), preferably at least 1.0 mm (one point zero millimeters). The at least one printing unit  01  preferably comprises at least one cleaning device  18  and/or at least one cleaning system  61 . 
     In a printing operating mode of the printing press, for example, at least one printing substrate  03  is guided along the transport direction T by means of the at least one printing substrate guide element  02 , through a spatial area between the respective printing substrate guide element  02  and the relevant nozzle bar  04 . The at least one print head  08  is positioned with at least one exit surface  09  in each case in the relevant nozzle bar  04 , facing the printing substrate guide element  02 . 
     The at least one nozzle bar  04  comprises at least one print head  08 , and in particular at least two print heads  08 . The at least two print heads  08  are preferably arranged next to one another, in particular adjacent to one another. Preferably, the at least two print heads  08  are arranged along the y direction next to one another, in particular abutting one another, preferably adjacent to one another, and/or preferably in a partially overlapping manner in the x direction. The individual print heads  08  of the relevant nozzle bar  04  are preferably arranged along the y direction within at least one row, preferably within at least two, in particular parallel, rows of print heads  08 . Preferably, the respective exit surfaces  09  of at least two print heads  08  that are arranged next to one another, and preferably adjacent to one another, are in each case positioned spaced apart from one another, in particular in the y direction, in particular within a row, by the at least one positioning gap  07 . Preferably, the at least two print heads  08  that are arranged next to one another in the y direction are arranged spaced apart from one another by the at least one positioning gap  07 . More preferably, the at least two print heads  08  that are arranged next to one another in the y direction, in particular adjacent to one another, in particular the respective exit surfaces  09  of the print heads  08 , which are in particular arranged next to one another in the y direction, delimit the corresponding positioning gap  07  in the y direction. This, for example, facilitates a positioning of the respective print heads  08 . 
     In one exemplary embodiment of a nozzle bar  04 , the print heads  08  of the nozzle bar  04 , which are preferably arranged in a row in the y direction, are in each case arranged so as to at least partially diagonally overlap, for example in the x direction, preferably in the transport direction T, and/or the respective exit surfaces  09  of the corresponding print heads  08  are preferably arranged spaced apart from one another in the y direction by the respective one positioning gap  07 . 
     In an alternative embodiment of a nozzle bar  04 , the nozzle bar  04 , for example, comprises at least two, preferably parallel, rows of print heads  08 , wherein a row in the y direction comprises at least two print heads  08 , preferably a multiplicity of print heads  08 . The print heads  08  of the rows arranged in each case in the y direction are preferably in each case arranged offset from one another in the x direction, whereby the respective exit surfaces  09  of the print heads  08  that are in each case arranged offset from one another preferably at least partially overlap. 
     A print head  08  comprises the at least one exit surface  09  and at least one, in particular at least two bearing surfaces  11 . The at least one bearing surface  11  is preferably configured as a spacer surface  11 . The bearing surface  11  is preferably configured in such a way that the exit surface  09  is arranged to avoid undesirable contact with components or other elements, for example when cleaning the exit surface  09 . The spacer surface  11  preferably extends across an entire extension of the respective print head  08 . However, dimensions across only a portion of the extension of the respective print head  08  are also possible. 
     The exit surface  09  of a print head  08  is a surface of the respective print head  08  that faces the transport path and is in particular located in a plane whose normal vector is situated parallel to the z direction. The exit surface  09  is, for example, configured as a parallelogram, preferably as a non-rectangular parallelogram. A trapezoid, in particular an isosceles trapezoid, is another exemplary embodiment of the exit surface  09 . Preferably, the exit surface  09  includes at least one opening, in particular a multiplicity of openings, through which the printing fluid can exit at least one volume, in particular a multiplicity of volumes, of the relevant print head  08 , preferably in the form of drops. 
     An exit direction of the at least one exit surface  09  is the direction in which the printing fluid exits and/or is able to exit the respective print head  09  through at least one opening of the corresponding exit surface  09 , in particular in the form of drops. The exit direction of the exit surface  09  is preferably, at least in one component, and more preferably completely, parallel to a surface normal of the exit surface  09  of the respective print head  08 . 
     The respective exit surfaces  09  of the relevant print heads  08  of a nozzle bar  04 , which are arranged next to one another in the y direction, are preferably arranged so as to at least partially abut one another in the x direction, and more preferably so as to at least partially overlap. Preferably, the sum of all exit surfaces  09  within at least one row of print heads  08  of a nozzle bar  04  which is arranged in the y direction, for example also of at least two rows, extends across the entire working width of the respective nozzle bar  04 . In this way, each position along a straight line, in the y direction on the transport path, is assigned an opening within an exit surface  09  of the relevant nozzle bar  04  through which the printing fluid can exit a volume of a corresponding print head  08  of the nozzle bar  04 . 
     Within a nozzle bar  04 , preferably at least two print heads  08  are in each case arranged next to one another, and in particular adjacent to one another, in the y direction. Within a row of print heads  08 , in particular two print heads  08  are in each case arranged adjacent to one another in the y direction. For example, for positioning the relevant at least two adjacent print heads  08  of the corresponding nozzle bar  04 , the respective exit surfaces  09  of the at least two print heads  08  are preferably arranged spaced apart from one another by the one positioning gap  07 . Preferably, the at least one positioning gap  07  in each case has an extension in the y direction of no more than 0.5 mm (zero point five millimeters), and in particular of no more than 0.2 mm (zero point two millimeters). In particular, the at least one positioning gap  07  has an extension in the y direction of at least 0.05 mm (zero point zero five millimeters), and preferably of at least 0.1 mm (zero point one millimeter). 
     Preferably, a cleaning direction G and/or the y direction has a preferably plane angle, in particular a positioning angle  46 , of at least 50° (fifty degrees), preferably of at least 60° (sixty degrees), and of no more than 130° (one hundred thirty degrees), preferably of no more than 120° (one hundred twenty degrees), with respect to a longitudinal direction of the positioning gap  07 , in a positive mathematical direction of rotation, which means rotated counterclockwise. From this, it is in particular apparent, for example, that the longitudinal direction of the positioning gap  07 , preferably of the positioning angles  46  of the longitudinal direction of the positioning gap  07 , is arranged in the plane spanned by the x direction and the y direction. The longitudinal direction of the positioning gap  07  is preferably the direction in which the greatest extension of the positioning gap  07  takes place. The longitudinal direction of the positioning gap  07  is preferably oriented, at least with one component, orthogonally to the cleaning direction G within the plane spanned by the x direction and the y direction. The positioning angle  46  thus, for example, corresponds to the at least partially diagonal overlap in the x direction of at least two print heads  08  that are arranged next to one another, and in particular adjacent to one another. 
     Preferably, at least one feed device  13  for ejecting a fluid is in each case assigned to the respective positioning gap  07 . The at least one feed device  13  is preferably in each case configured as a nozzle  13 , in particular as a cleaning nozzle  13 . More preferably, the feed device  13  is configured as a nozzle  13  for ejecting fluid, preferably a gaseous fluid and/or compressed gas. The feed device  13  is preferably arranged in such a way that a fluid, for example a compressed gas and/or a gas mixture, in particular air, and/or a liquid, is able to flow through the respective feed device  13  such that the fluid is able to exit the feed device  13 , in particular through an outlet opening  17 , in an outlet direction L. At least one component of the outlet direction L, preferably in the z direction, is preferably directed at the respective positioning gap  07 . Preferably, at least one feed device  13  for ejecting a fluid with an outlet direction L is assigned to the respective positioning gap  07 , wherein at least one component of the outlet direction L is directed at the respective positioning gap  07 . The outlet opening  17  of the feed device  13  is preferably directed at the positioning gap  07 , for example, from the top and/or from above the printing substrate guide element  02 , in the direction of the printing substrate guide element  02 . 
     The at least one feed device  13 , which is directed at the at least one positioning gap  07  between at least two print heads  08  that are arranged next to one another, for example, preferably impedes and/or prevents printing fluid and/or dirt from penetrating into the positioning gap  07 , and/or printing fluid and/or dirt from accumulating and/or depositing in the relevant positioning gap  07 . This, for example, during a cleaning process, supports the cleaning of the relevant positioning gap  07 , for example by the at least one cleaning device  18 , and/or impedes printing fluid and/or dirt from accumulating and/or depositing during a printing operation. 
     The feed device  13  preferably comprises at least one feed element  14  and/or at least one outlet element  16 ;  43 , wherein the at least one outlet element  16 ;  43  is preferably in each case configured as at least one delimiting element  16  and/or at least one opening element  43 , and/or the at least one outlet opening  17 . The feed device  13  preferably comprises at least one cavity, which is preferably connected to the at least one outlet opening  17 . For example, the at least one outlet element  16 ;  43  is in each case configured as at least one metal plate or a tube. The delimiting element  16  is preferably configured in a planar manner, for example as a planar metal plate. The at least one opening element  43  preferably includes at least one recess  17 , which more preferably is configured as the at least one outlet opening  17 . 
     In a preferred embodiment, the at least one feed device  13  is preferably in each case connected to at least one print head  08  of the relevant print heads  08 , which delimit the respective positioning gap  07 . In addition or as an alternative, the at least one nozzle bar  04  preferably comprises the at least one feed device  13 , wherein the feed device  13  is preferably positioned in the z direction on the side of the exit surface  09  which faces away from the at least one opening of the respective exit surface  09 . In addition or as an alternative, the at least one nozzle bar  04  preferably comprises the at least one feed device  13 , wherein the feed device  13  is preferably arranged in the z direction on the side, facing away from the transport path, of at least one exit surface  09  of at least one print head  08  of the corresponding nozzle bar  04 , and/or wherein the respective outlet direction L of the at least one feed device  13  is in each case directed at at least one positioning gap  07  between two print heads  08  that are in particular adjacent to one another, preferably in the y direction. 
     The at least one feed device  13  is preferably arranged in the z direction of the side of the respective exit surface  09  which faces away from the transport path. More preferably, the at least one feed device  13  is positioned on the side of the print head  08 , in particular of the exit surface  09 , at which the print head  08  is attached to the corresponding nozzle bar  04 . More preferably, the at least one feed device  13  is positioned in such a way that the outlet direction L is directed from a side of the print head  08 , in particular a side of the exit surface  09 , at the at least one positioning gap  07  at which the print head  08  is attached to the corresponding nozzle bar  04 . 
     The feed device  13  is preferably arranged so as to be spaced apart from the positioning gap  07  in the z direction. More preferably, the feed device  13  is arranged so as to abut the positioning gap  07  in the z direction. The outlet opening  17  is preferably arranged so as to be spaced apart from the positioning gap  07  in the z direction. More preferably, the outlet opening  17  is arranged so as to abut the positioning gap  07  in the z direction. This means that the feed device  13 , in particular the respective outlet opening  17 , is arranged so as to be spaced apart, preferably in the z direction, from the respective exit surfaces  09  of two print heads  08 , which are arranged next to one another in the y direction, and whose exit surfaces  09  delimit the corresponding positioning gap  07 . 
     The outlet direction L is preferably a direction in which a fluid, for example a gas and/or a gas mixture, in particular air, and/or a liquid, is able to exit the relevant feed device  13 , preferably through the at least one outlet element  16 ;  43 , in particular the at least one outlet opening  17 . The outlet direction L is preferably parallel, at least in one component, and/or shows an identical direction to the exit direction of the at least one exit surface  09  of a print head  08  of the nozzle bar  04 . More preferably, at least one component of the outlet direction L is parallel and/or shows an identical direction to the surface normal of the exit surface  09  of the respective print head  08  and/or a direction in which the printing fluid is able to exit the respective exit surface  09 . 
     The outlet direction L is preferably parallel to a main direction, which is preferably established by at least one side wall of the feed device  13 , which more preferably is established by the at least one delimiting element  16 . The outlet direction L preferably has at least one component in the z direction, wherein the component in the z direction preferably faces the transport path. For example, the outlet direction L includes at least one component in the z direction and at least one component in the x direction, wherein the component in the z direction is greater than the component in the x direction. 
     The outlet direction L is preferably a direction within a plane spanned at the position of the positioning gap  07 , for example shifted along the y direction, by the z direction and at least one direction of a shortest delimitation, which is spanned in a plane of the x direction and y direction, of the respective exit surface  09  of the relevant print head  08 , which preferably delimits the positioning gap  07 . 
     In a preferred embodiment, the at least one feed device  13 , in the y direction, has an extension that is identical to the extension of the respective positioning gap  07  in the y direction. More preferably, the at least one feed device  13 , in the y direction, has an extension of no more than 0.5 mm (zero point five millimeters), and in particular of no more than 0.2 mm (zero point two millimeters). More preferably, the at least one feed device  13 , in the y direction, has an extension of at least 0.05 mm (zero point zero five millimeters), and preferably of at least 0.1 mm (zero point one millimeter). 
     In the plane that is spanned by the z direction and at least one direction of the shortest delimitation, which is spanned in a plane of the x direction and y direction, of the respective exit surface  09  of the relevant print head  08 , wherein the respective exit surface  09  delimits the positioning gap  07 , the outlet opening  17  is preferably configured in such a way that the relevant outlet opening  17  in the z direction, away from the respective exit surface  09 , and in particular away from the transport path, has a smaller dimension than in the z direction close to the exit surface  09 , and in particular close to the transport path. In the plane that is spanned at the position of the positioning gap  07 , for example shifted along the y direction, by the z direction and at least one direction of the shortest delimitation, which is spanned in a plane of the x direction and y direction, of the respective exit surface  09  of the relevant print head  08 , which delimits the positioning gap  07 , the outlet opening  17  preferably has a shape that corresponds to a two-dimensional longitudinal section of a cone, for example. In addition or as an alternative, the diameter of the outlet opening  17 , measured in the direction of the shortest delimitation, which is spanned in a plane of the x direction and y direction, of the exit surface  09 , which delimits the positioning gap  07 , preferably increases along the z direction in the direction of the transport path. The at least one outlet opening  17  preferably has a maximum diameter at the point of the feed device  13  which has the smallest distance with respect to the respective positioning gap  07 . More preferably, the maximum diameter of the corresponding outlet opening  17  is greater than the extension of the at least one exit surface  09  of the relevant print head  08 , which is arranged at the corresponding positioning gap  07 , in the direction of the shortest delimitation of the respective exit surface  09 . 
     Preferably, the delimiting element  16  delimits the respective outlet opening  17  in the y direction, preferably on one side. The respective delimiting element  16  is preferably in direct contact with the respective opening element  43 . More preferably, the feed element  14  is in direct contact with the respective opening element  43 , so that a connection preferably exists between at least one cavity of the feed element  14  and the respective outlet opening  17 . More preferably, the opening element  43  and in particular the respective outlet opening  17  of the corresponding feed device  13  is arranged between the respective delimiting element  16  and the respective feed element  14 . 
     The feed element  14  preferably comprises the at least one cavity, wherein the cavity is connected to at least one source for supplying the at least one fluid, for example a gas and/or a gas mixture, in particular air, and/or a liquid, and to the outlet opening  17 . 
     For example, a fluid, for example a gas and/or gas mixture, and/or a liquid, can be provided by the at least one source. For example, the at least one fluid, in particular compressed gas, flows through the cavity of the feed element  14  and preferably impinges on the delimiting element  16  through the recess  17  of the opening element  43 . At the delimiting element  16 , the fluid, for example the gas and/or the gas mixture and/or the liquid, is deflected in such a way, for example, that the fluid preferably exits the respective feed device  13  in the outlet direction L through the at least one outlet opening  17 . The fluid, for example the gas and/or the gas mixture and/or the liquid, preferably has a pressure of at least 0.1 bar, in particular of at least 0.2 bar, and of no more than 0.7 bar, in particular of no more than 0.5 bar, when exiting the feed device  13 .  FIG.  3    indicates an exit of the fluid in the exit direction L by dotted lines by way of example. 
     The nozzle bar  04  comprises at least one positioning guide  06 , which is preferably arranged so as to be movable, in particular linearly movable. The at least one nozzle bar  04  preferably has the at least one printing position and at least one service position. The respective nozzle bar  04  is, in particular the respective print heads  08  of the nozzle bar  04  are, preferably selectively to be arranged and/or can be arranged and/or is arranged in the at least one printing position and/or at least one idle position and/or at least one service position by the respective positioning guide  06 . The at least one nozzle bar  04  is preferably selectively arranged in the printing position or in the at least one service position. The positioning guide  06  is preferably configured as a linear guide. For example, the at least one nozzle bar  04  in each case comprises at least one positioning guide  06  in the transverse direction A upstream and downstream from the nozzle bar  04 . The nozzle bar  04  is preferably configured to move and/or to be movable, by way of a movement in a direction which has a greater or maximal component in the vertical direction or the z direction and a smaller or minimal component in the horizontal direction, from the printing position into the idle position or into the at least one service position, and/or from the idle position into the printing position or into the at least one service position, and/or from the at least one service position into the printing position or into the idle position. Preferably, the at least one nozzle bar  04  is, preferably at least two nozzle bars  04  of the printing unit  01 , more preferably at least four nozzle bars  04  of the printing unit  01 , are moved and/or configured to move, for example simultaneously, by way of the movement in a direction which has a greater or maximal component in the vertical direction or the z direction and a smaller or minimal component in the horizontal direction, from the printing position into the idle position or into the at least one service position, and/or from the idle position into the printing position or into the at least one service position, and/or from the at least one service position into the printing position or into the idle position. The at least one service position is, preferably all service positions are, preferably arranged in the vertical direction, preferably in the z direction, above the printing position. The at least one nozzle bar  04  is preferably moved from the printing position into the at least one service position, preferably into all service positions, by way of a movement in the vertical direction and/or in the z direction and/or in the upward direction. The at least one nozzle bar  04  is preferably moved from the printing position into the at least one service position, preferably into all service positions, by way of a movement in the vertical direction, preferably in the z direction, more preferably in the upward direction. The at least one nozzle bar  04 , preferably the at least one nozzle bar  04  of the at least four nozzle bars  04 , is preferably arranged in the at least one service position, preferably in all service positions, in the vertical direction and/or in the z direction above the printing position. Preferably, the at least one service position is, preferably all service positions are, arranged above a plane of the transport path, preferably at the position of the transport path which has the shortest distance with respect to the at least one nozzle bar  04 . Preferably, the at least one nozzle bar  04  is moved with a largest component of its movement direction in the z direction, preferably in the vertical direction. Preferably, the at least one service position has, preferably all service positions have, a distance of greater than zero with respect to the printing position, preferably in the z direction. The at least one nozzle bar  04 , preferably the at least one nozzle bar  04  of the at least four nozzle bars  04 , is selectively arranged in the printing position or in the at least one service position. Preferably, the at least one nozzle bar  04  is moved in a direction having a larger vertical component and a smaller horizontal component from the printing position into the at least one service position and/or from the at least one service position into the printing position. 
     The at least one nozzle bar  04 , preferably the at least one nozzle bar  04  of the at least four nozzle bars  04 , preferably has the at least one idle position. The idle position is preferably a position in which the at least one print head  08  can be removed from the printing press and/or the at least one printing unit  01  and/or the at least one nozzle bar  04  and/or inserted into the printing press and/or the at least one printing unit  01  and/or the at least one nozzle bar  04 . Preferably, at least one print head  08  of the at least one nozzle bar  04  arranged in the idle position can be removed from the at least one printing unit  01 . In particular, an operator preferably has more space available in the idle position to reach the at least one print head  08 , while in the at least one service position preferably only sufficient space is available to be able to carry out internal, in particular automatic processes within the printing press, for example a cleaning operation of at least one exit surface  09  of at least one print head  08 . Preferably, a distance between the at least one print head  08  of the nozzle bar  04  arranged in the at least one idle position and the transport path of printing substrate  03  is greater than in the printing position and in the at least one service position, preferably all service positions. The idle position is preferably arranged in the vertical direction, preferably in the z direction, above the printing position. 
     The at least one service position is preferably a position in which the at least one print head  08  of the relevant nozzle bar  04  can be and/or is serviced, for example cleaned and/or aligned, preferably without removing the corresponding print head  08  from the nozzle bar  04  and/or the printing unit  01  and/or the printing press. The respective service position of a nozzle bar  04 , in particular of the relevant print heads  08 , is preferably characterized in that different nozzle bars  04  arranged in their respective service positions have different distances with respect to one another than in their respective printing positions and/or in their respective idle positions. Preferably, the distance between the at least one print head  08 , more preferably the respective exit surface  09  of a print head  08  arranged in a service position, and the intended transport path for at least one printing substrate  03  and/or the at least one printing substrate  03  and/or the printing substrate guide element  02  assigned to the respective nozzle bar  04  is greater than in the corresponding printing position. Preferably, the distance between the at least one print head  08  of the at least one nozzle bar  04  arranged in the at least one service position and the transport path of the printing substrate  03  is greater than in the printing position. 
     The at least one nozzle bar  04  of the at least four nozzle bars  04  preferably has the at least one printing position and at least one service position. The at least one nozzle bar  04  preferably has at least one service position. More preferably, the at least one nozzle bar  04  has at least two, more preferably at least three, service positions. The at least one service position is preferably configured as a first service position. At least one second service position is preferably configured as the second service position. At least one third service position is preferably configured as the third service position. In a preferred embodiment, the at least two service positions, in particular the first service position and the second service position, are different positions of the at least one nozzle bar  04 . A first service position of the at least one nozzle bar  04  is preferably configured as a cleaning position. A second service position of the at least one nozzle bar  04  is preferably configured as an intensive cleaning position. A third service position of the at least one nozzle bar  04  is preferably configured as a depot position. For example, the cleaning position is identical to the intensive cleaning position of the nozzle bar  04 . In an exemplary, alternative embodiment, the cleaning position of the nozzle bar  04  differs from its intensive cleaning position. 
     In the first service position, this being the cleaning position, the at least one nozzle bar  04  preferably enters into a functional connection with at least one cleaning device  18 . The at least one nozzle bar  04  is preferably arranged in the at least one first service position when contact with the at least one cleaning device  18  occurs. The first service position, this being the cleaning position, preferably corresponds to a positioning of the nozzle bar  04  during a contactless cleaning operation of the at least one exit surface  09  of the at least one print head  08  of the relevant nozzle bar  04 . The first service position preferably corresponds to a positioning of the at least one nozzle bar  04  during a contactless cleaning operation of the at least one print head  08 , preferably of the at least one exit surface  09  of the at least one print head  08 , of the at least one nozzle bar  04 , preferably a cleaning operation by means of the at least one cleaning device  18 . The first service position preferably corresponds to a positioning of the at least one nozzle bar  04  during a contactless cleaning operation of the at least one print head  08 , preferably of the at least one exit surface  09  of the at least one print head  08 , more preferably of the at least two print heads  08 , more preferably of the at least one row of print heads  08 , of the at least one nozzle bar  04 . The at least one nozzle bar  04  is preferably positioned in the first service position during the contactless cleaning operation of the at least one print head  08 , preferably of the at least one exit surface  09  of the at least one print head  08 , of the at least one nozzle bar  04 . The contact of the at least one print head  08  with the at least one cleaning device  18  preferably corresponds to an indirect contact. Preferably in addition or as an alternative, the contact of the at least one print head  08  with the at least one cleaning device  18  preferably corresponds to a contactless cleaning operation of the at least one print head  08 , preferably of the at least one exit surface  09  of the at least one print head  08 . 
     Preferably, the at least one nozzle bar  04  enters into a functional connection with at least one cleaning system  61 , preferably with at least one contact element  64  of the at least one cleaning system  61 , in the second service position, this being the intensive cleaning position. The at least one nozzle bar  04  is arranged in the at least one second service position when contact with the at least one cleaning system  61  occurs. The second service position, this being the intensive cleaning position, preferably corresponds to a positioning of the nozzle bar  04  while at least one of the print heads  08  of this nozzle bar  04  is in direct contact with the at least one contact element  64  of the at least one cleaning system  61 . The distance between the at least one print head  08  of the at least one nozzle bar  04  arranged in the second service position and the transport path of printing substrate  03  is preferably greater than in the printing position. The at least one nozzle bar  04  is preferably positioned in the second service position when contact with the at least one cleaning system  61  occurs. 
     In the third service position, the at least one nozzle bar  04  preferably establishes contact with at least one sealing element  56  and/or with the at least one cleaning device  18 , for example preferably when the cleaning device  18  comprises the at least one sealing element  56 . The third service position, this being the depot position, preferably corresponds to a positioning of the at least one nozzle bar  04  in indirect contact with the at least one sealing element  56 . In the third service position, the at least one sealing element  56  is preferably arranged in direct contact with the at least one nozzle bar  04 . Preferably, the at least one sealing element  56  is configured to at least partially seal the at least one exit surface  09  of the at least one print head  08  of the nozzle bar  04 , preferably the at least two exit surfaces  09  of at least two print heads  08  arranged next to one another in the y direction and/or transverse direction A, more preferably at least four exit surfaces  09  of at least four print heads  08  arranged next to one another in the y direction and/or transverse direction A, more preferably of all print heads  08  arranged next to one another in the y direction and/or transverse direction A, preferably with respect to external influences, preferably when the nozzle bar  04  is in the depot position. 
     Above and below, a functional connection preferably describes that a first element is at least indirectly or directly connected to a second element and/or is configured to operate together with the second element. For example, a functional connection shall also be understood to mean that the first element is configured to operate as a function of the configuration and/or the arrangement and/or a movement and/or an operation of the second element. 
     A distance between the at least one print head  08  of the at least one nozzle bar  04  arranged in the at least one service position, preferably in all service positions, and a transport path of printing substrate  03  is preferably greater than in the printing position. In the first service position, this being the cleaning position, the at least one nozzle bar  04  preferably has a first distance with respect to the transport path. In the second service position, this being the intensive cleaning position, the at least one nozzle bar  04  preferably has a second distance with respect to the transport path, which more preferably differs from the first distance. The distance of the second service position of the nozzle bar  04 , in particular of the at least one exit surface  09  of the at least one print head  08  of the nozzle bar  04 , with respect to the transport path is preferably smaller than in the first service position. In the third service position, this being the depot position, the at least one nozzle bar  04  preferably has a third distance with respect to the transport path, which preferably differs from the first distance. For example, the third distance, this being the distance of the nozzle bar  04  arranged in the depot position, with respect to the transport path is smaller than the first distance, this being the distance of the nozzle bar  04  arranged in the cleaning position. The third distance of the at least one nozzle bar  04  in the third service position with respect to the transport path of printing substrate  03  is preferably a distance that differs from the first distance of the at least one nozzle bar  04  in the first service position. The third distance is preferably smaller than the first distance. The third distance between the at least one print head  08  of the nozzle bar  04  arranged in the at least one third service position and the transport path of printing substrate  03  is preferably greater than in the printing position. 
     The cleaning direction G is preferably a horizontal direction G in which a cleaning unit  26  and/or at least one cleaning element  31  and/or at least one removal unit  63 , in particular each for carrying out a cleaning step, are arranged to be movable and/or are configured to move. The cleaning device  18  preferably comprises the at least one cleaning unit  26  and the at least one cleaning element  31 . The cleaning system  61  preferably comprises the at least one removal unit  63 . The cleaning direction G preferably has at least one component that is situated parallel to the transverse direction A and/or parallel to the y direction, and is preferably oriented opposite the y direction. The cleaning direction G more preferably is situated parallel to the transverse direction A and/or parallel to the y direction, and is preferably oriented opposite the y direction. The cleaning direction G is preferably oriented orthogonally to at least the transport direction T that is intended for transporting at least one printing substrate  03  and/or orthogonally to the x direction. The cleaning direction G is preferably the direction in which an element cleaning the at least one print head  08  passes this at least one print head  08 . The cleaning direction G preferably corresponds to a direction of the longest side of the at least one nozzle bar  04 . 
     Preferably, the at least one cleaning unit  26 , and more preferably at least one cleaning element  31 , is arranged so as to be movable and/or to move in and/or counter to the cleaning direction G. Preferably, the at least one cleaning unit  26 , and more preferably the at least one cleaning element  31 , is arranged so as to be movable at least in the cleaning direction G during a cleaning process of the at least one exit surface  09  of the at least one print head  08 . Preferably in addition or as an alternative, the at least one removal unit  63  is arranged so as to be movable and/or to move in and/or counter to the cleaning direction G, in particular during a cleaning process of the at least one exit surface  09  of the at least one print head  08 . 
     The at least one printing unit  01  comprises the at least one cleaning device  18 . The at least one cleaning device  18  comprises at least one cleaning element  31  including at least one fluid input  38  configured as a fluid supply opening  38 . Preferably in addition or as an alternative, the at least one cleaning device  18  is configured to at least temporarily make indirect contact with the at least one print head  08 , at least by way of at least one cleaning fluid ejected by the at least one fluid supply opening  38 . Preferably in addition or as an alternative, the at least one cleaning device  18  is configured to make indirect contact with the at least one print head  08 , that is, is configured to preferably clean the same in a contactless manner, and/or makes indirect contact therewith, at least by way of at least one cleaning fluid ejected through the at least one fluid supply opening  38 . The at least one cleaning device  18  preferably makes indirect contact with the at least one print head  08 , at least by way of at least one cleaning fluid ejected through the at least one fluid supply opening  38 . Preferably, the indirect contact of the at least one cleaning device  18  with the at least one print head  08  and/or with the at least one nozzle bar  04  thus describes that the at least one cleaning device  18 , preferably the at least one cleaning element  31 , at least for the duration of the cleaning operation, and preferably permanently, has a distance of greater than zero with respect to the at least one exit surface  09 . Preferably, the at least one cleaning device  18 , preferably the at least one cleaning element  31 , is configured to clean the at least one print head  08  of the at least one nozzle bar  04 , preferably at least the at least one exit surface  09 , in a contactless manner in indirect contact. Preferably, the at least one cleaning device  18  is configured to clean the at least one print head  08 , preferably the at least one exit surface  09  of the at least one print head  08 , more preferably at least two exit surfaces  09  of at least two print heads  08 , more preferably at least the exit surfaces  09  of all print heads  08  of a row, in a contactless manner. The printing unit  01  comprises at least four cleaning devices  18 . A cleaning device  18  is in each case configured to clean and/or cleans a respective nozzle bar  04  of the at least four nozzle bars  04 . 
     The at least one cleaning device  18  comprises at least one guide system  19 . The at least one guide system  19  comprises at least one guide element  53 . The at least one cleaning device  18  is configured to move and/or to be movable and/or is moved along the at least one guide element  53 , and preferably is in particular displaced in a rectilinear manner. The at least one cleaning device  18  is preferably arranged so as to be movable and/or to move, preferably in a linear manner, by way of the at least one guide system  19 , preferably by means of at least one cleaning drive  21 . 
     The at least one guide element  53  of the at least one guide system  19  is configured as a bar and/or a rod and/or a rail and/or a linear guide. Preferably, at least one guide element  53  of the at least one guide system  19  is in each case arranged upstream, and at least one guide element  53  of the at least one guide system  19  is in each case arranged downstream, from the at least one nozzle bar  04 , in the transverse direction A and/or in the y direction. For example, at least one guide element  53  of the at least one guide system  19  is in each case arranged at a housing of the at least one printing unit  01  upstream and downstream from the at least one nozzle bar  04 , in the transverse direction A. 
     The at least one guide element  53  of the at least one guide system  19  preferably has its longitudinal direction along its longest extension. The longitudinal direction of the at least one guide element  53  is preferably arranged in the plane spanned by the x direction and the z direction. For example, the longitudinal direction of the at least one guide element  53  is arranged in a plane whose normal vector corresponds to the transverse direction A and/or the y direction. The longitudinal direction of the at least one guide element  53  preferably has at least one first component in the x direction, preferably a horizontal component, and at least one second component in the z direction, preferably a vertical component. The component of the longitudinal direction in the x direction is preferably greater than the component of the longitudinal direction in the z direction. Preferably, the longitudinal direction of the at least one guide element  53  of the at least one guide system  19  thus preferably has a larger horizontal component than its vertical component. 
     The at least one guide element  53  preferably has at least one guide path. The guide path is preferably configured for guiding the at least one cleaning device  18 . The at least one cleaning device  18  is preferably moved along the guide path of the at least one guide element  53 . The guide path along the at least one guide element  53  is preferably parallel to the longitudinal direction of the at least one guide element  53 . The guide path along the at least one guide element  53  is preferably arranged in a plane whose normal vector corresponds to the transverse direction A and/or the y direction. The guide path along the at least one guide element  53  within the plane preferably has a larger horizontal component than its vertical component. The at least one cleaning device  18  is preferably moved along the at least one guide element  53  along the guide path in a plane having a larger horizontal component than a vertical component. 
     The at least one guide system  19  preferably comprises at least one crossbar  54 , which is preferably configured as an attachment  54 . The crossbar  54  is preferably configured as a mechanical carrier. Preferably, the at least one cleaning device  18  is, preferably positively, connected to the at least one crossbar  54 . The at least one cleaning device  18  and the at least one crossbar  54  are preferably configured to move and/or be movable jointly along the at least one guide element  53  of the at least one guide system  19 , and in particular so as to be displaced in a linear or rectilinear manner. The at least one cleaning device  18  is preferably connected to the at least one guide element  53  of the at least one guide system  19  via the at least one crossbar  54  of the at least one guide system  19 , the crossbar preferably configured as an attachment  54 . The at least one cleaning device  18  is preferably in each case connected to the at least one guide element  53  via at least one first crossbar  54  in the transverse direction A and/or in the y direction, upstream from the at least one nozzle bar  04 , and via at least one second crossbar  54  in the transverse direction A and/or in the y direction, downstream from the at least one nozzle bar  04 . 
     Preferably, at least one guide element  53  is arranged in the transverse direction A upstream from, and at least one guide element  53  is arranged in the transverse direction A downstream from, the at least one nozzle bar  04 . 
     Preferably, the at least one cleaning device  18  has a distance with respect to the at least one guide element  53  of the at least one guide system  19  which is preferably constant and/or which is established and/or is being established by the at least one crossbar  54  of the at least one guide system  19 . Preferably, the at least one first service position, this being the cleaning position, and/or the at least one third service position, which is the depot position, of the at least one nozzle bar  04  are established and/or matched to the constant distance by way of the preferably constant distance between the at least one cleaning device  18  and the at least one guide element  53 . 
     The at least one printing unit  01  comprises at least two, more preferably at least four, cleaning devices  18 . At least two nozzle bars  04  of the at least four nozzle bars  04  are configured to make contact, and/or make contact, with at least one respective cleaning device  18  of the at least two cleaning devices  18 . A printing unit  01  comprises at least one cleaning device  18  per nozzle bar  04 . At least two cleaning devices  18  comprise at least one shared guide system  19 . In particular, at least two cleaning devices  18  are connected to the at least one, preferably shared, guide system  19  and/or are configured to be movable and/or to move and/or are moved by the at least one shared guide system  19 . The at least two cleaning devices  18  comprise at least one shared guide element  53  configured as a rail. For the at least two cleaning devices  18 , the at least one shared guide system  19  comprises the at least one shared guide element  53 , preferably at least one shared guide element  53 , in the transverse direction A upstream and/or at least one shared guide element  53  in the transverse direction A downstream from the at least one nozzle bar  04 . The at least two cleaning devices  18  are preferably connected to the at least one crossbar  54  and/or the at least two cleaning devices  18  and the at least one crossbar  54  are configured to move and/or be movable jointly along the at least one guide element  53  of the at least one guide system  19 , and in particular so as to be displaced in a linear manner. The at least two cleaning devices  18  are jointly connected to the at least one guide system  19  and/or are configured to be movable and/or to move and/or are moved jointly by the at least one guide system  19  from the at least one usage position into the at least one storage position, or vice versa. The at least two cleaning devices  18  are jointly connected to the at least one guide system  19  and/or the at least two cleaning devices  18  preferably simultaneously have the at least one storage position or the at least one usage position. 
     The at least two cleaning devices  18  preferably comprise at least two shared guide systems  19 . At least one of the at least two guide systems  19  is preferably in each case arranged upstream from the at least one nozzle bar  04  in the transverse direction A and/or in the y direction, and/or at least one of the at least two guide systems  19  is preferably in each case arranged downstream from the at least one nozzle bar  04  in the transverse direction A and/or in the y direction. 
     The at least two cleaning devices  18  preferably have an angle of inclination with respect to the z direction which corresponds to an inclination with respect to the z direction of the nozzle bar  04  and/or of the at least one print head  08  of the nozzle bar  04 . The inclination preferably in each case corresponds to the inclination of the assigned nozzle bar  04  and/or its print head  08 . Preferably, the at least two cleaning devices  18 , which comprise the at least one shared guide element  53 , preferably have an angle of inclination with respect to the z direction which corresponds to an inclination with respect to the z direction of the nozzle bar  04  and/or of the at least one print head  08  of the nozzle bar  04 . For example, the at least two cleaning devices  18 , which comprise the at least one shared guide element  53 , have differing angles of inclination with respect to the z direction. For example, the inclination of the at least two cleaning devices  18  with respect to one another has an angle of at least 1° (one degree), preferably of at least 3° (three degrees), more preferably of 4° (four degrees). The angle of inclination with respect to the z direction of the respective cleaning device  18  preferably corresponds to an inclination with respect to the z direction of the nozzle bar  04  and/or of the print heads  08 , this cleaning device  18  being assigned to the nozzle bar  04  or the print heads  08 . 
     The at least one cleaning device  18  has at least one storage position and at least one usage position. The at least one cleaning device  18  has the at least one storage position. 
     The at least one storage position of the at least one cleaning device  18  is a position in which the at least one cleaning device  18  is arranged outside the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 , for example established by the at least one printing substrate guide element  02  situated opposite the nozzle bar  04 . The at least one storage position is arranged outside the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . In particular, the storage position of the at least one cleaning device  18  corresponds to a safekeeping position when the printing press is in an operating mode in which the at least one cleaning device  18  is not employed. 
     In the at least one storage position, the at least one cleaning device  18  is arranged along the x direction upstream or downstream from the at least one nozzle bar  04 . In its storage position, the at least one cleaning device  18  is arranged and/or is being arranged in a circumferential direction of the at least one printing substrate guide element  02  that is situated opposite and/or assigned to the at least one nozzle bar  04 , and/or along the transport path of printing substrate  03  upstream or downstream from the at least one nozzle bar  04 . In the at least one storage position, the at least one cleaning device  18  is arranged and/or is being arranged along the transport direction T of printing substrate  03  upstream or downstream from the at least one nozzle bar  04 , wherein the transport direction T is determined and/or is being determined at the position of the transport path of printing substrate  03  beneath the at least one nozzle bar  04 . In the at least one storage position, the at least one cleaning device  18  is arranged and/or is being arranged along the transport direction T of printing substrate  03  upstream or downstream from an area between the at least one nozzle bar  04  and the transport path of printing substrate  03 , wherein the transport direction T is determined and/or is being determined at the position of the transport path of printing substrate  03  beneath the at least one nozzle bar  04 . The storage position corresponds to a position along the at least one guide element  53  of the at least one guide system  19 , in particular along its longitudinal direction, outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . The arrangement upstream or downstream from the at least one nozzle bar  04  preferably corresponds to an arrangement upstream or downstream from the area that is a spatial area and that is established by outside edges of the at least one nozzle bar  04  that preferably extend in the z direction, that is, preferably vertically, wherein the outside edges are projected up to the transport path. The outside edges preferably correspond to the outwardly directed sides of a housing of the at least one nozzle bar  04 , which are preferably perpendicularly situated on the plane of the x direction with the y direction. In the storage position, the at least one cleaning device  18  is preferably arranged spaced apart from the outside edges of the at least one nozzle bar  04  at a distance of greater than zero in the x direction. Preferably, the at least one fluid supply opening  38  of the at least one cleaning element  31  of the at least one cleaning device  18  arranged in the storage position, preferably at least one centroid of a delimitation of the fluid supply opening  38 , has a preferably first preferably relative distance and/or is arranged at the relative distance, preferably a distance in the x direction and/or in the transport direction T, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one fluid supply opening  38  of the at least one cleaning element  31  of the at least one cleaning device  18  arranged in the storage position, preferably of the centroid of the delimitation of the fluid supply opening  38 , with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is at least twice, preferably at least two point five times, more preferably at least three times, more preferably at least five times as large as an extension of the at least one cleaning device  18  in the transport direction T. Preferably, the transport direction T is determined at the position of the transport path having the shortest distance with respect to the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one cleaning device  18 . The relative distance in the storage position is preferably at least so large that contact between the at least one nozzle bar  04 , when arranged in the printing position, and the at least one cleaning device  18  is avoided. The arrangement of the storage position preferably enables a compact configuration of the at least one printing unit  01 . The at least one cleaning device  18  is preferably easy to handle. Preferably, the at least one cleaning device  18  is serviced and/or the at least one cleaning device  18  is removed in the storage position. 
     The at least one cleaning device  18  has the at least one usage position. 
     The at least one usage position of the at least one cleaning device  18  is preferably a position in which the at least one cleaning device  18  is arranged within the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 , for example established by the at least one printing substrate guide element  02  situated opposite the nozzle bar  04 . The at least one usage position is preferably arranged within the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . In the at least one usage position, the at least one cleaning device  18  is preferably arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . In particular, the usage position of the at least one cleaning device  18  corresponds to a position when the printing press is in an operating mode in which the at least one cleaning device  18  is employed. The usage position of the at least one cleaning device  18  preferably corresponds to a position in which the cleaning device  18  is in direct or indirect contact with at least one print head  08 , which is in particular to be cleaned, of the relevant nozzle bar  04 , and/or preferably to a position in which the cleaning device  18  is arranged to clean the at least one print head  08  of the relevant nozzle bar  04 . In the usage position, the at least one cleaning device  18  is preferably at least partially arranged in the area between the at least one nozzle bar  04  and the transport path, in particular between the shortest connection between the at least one nozzle bar  04  and the transport path, wherein the transport path, for example, is established by the at least one printing substrate guide element  02  assigned to the nozzle bar  04 . Preferably, the at least one fluid supply opening  38  of the at least one cleaning element  31  of the at least one cleaning device  18  arranged in the usage position, preferably of the centroid of the delimitation of the fluid supply opening  38 , has a preferably second preferably relative distance and/or is arranged at the relative distance, preferably a distance in the x direction and/or in the transport direction T, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one fluid supply opening  38  of the at least one cleaning element  31  of the at least one cleaning device  18 , preferably of the centroid of the delimitation of the fluid supply opening  38 , with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is greater in the storage position than in the usage position. Preferably, the preferably relative distance of the at least one fluid supply opening  38  of the at least one cleaning element  31  of the at least one cleaning device  18  arranged in the usage position, preferably of the centroid of the delimitation of the fluid supply opening  38 , with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is no more than one time, preferably no more than zero point five times, as large as the extension of the at least one cleaning device  18  in the transport direction T. Preferably, the transport direction T is determined at the position of the transport path having the shortest distance with respect to the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one cleaning device  18 . 
     In the at least one usage position, the at least one cleaning device  18  is preferably arranged within the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . Preferably in addition or as an alternative, in the at least one storage position, the at least one cleaning device  18  is arranged along the x direction upstream or downstream from the at least one nozzle bar  04 . 
     Preferably, the configuration of the storage position and/or the configuration of the usage position increase the compact design of the printing press. Preferably, lateral displacement, for example in the y direction, of the at least one nozzle bar out of the printing position into the at least one service position is superfluous. 
     Above and below, the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03  preferably describes the spatial area that has the shortest distance between the nozzle bar  04 , in particular the at least one print head  08  of the nozzle bar  04 , and the transport path. Above and below, the area between the at least one nozzle bar  04  and the transport path of printing substrate  03  is preferably the spatial area that has the shortest distance between the nozzle bar  04 , in particular the at least one print head  08  of the nozzle bar  04 , more preferably the at least one exit surface  09  of the at least one print head  08  of the nozzle bar  04 , and the transport path. The shortest distance of the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03  is preferably directed in the z direction, preferably vertically. The spatial area, that is, preferably the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 , is preferably delimited by outside edges of the at least one nozzle bar  04  which preferably extend in the z direction, that is, preferably vertically, wherein the outside edges are projected up to the transport path. The outside edges preferably correspond to the outwardly directed sides of a housing of the at least one nozzle bar  04 , which are preferably perpendicularly situated on the plane of the x direction with the y direction. Preferably, the at least one nozzle bar  04  is delimited in the transport direction T of printing substrate  03 , preferably in the leading and trailing directions, by a respective delimiting plane, preferably by a respective delimiting plane of at least two delimiting planes, wherein the transport direction T is preferably determined at the point of the transport path having the shortest distance with respect to the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04 . The at least one delimiting plane is, preferably at least two delimiting planes are, preferably situated perpendicularly on a plane, wherein the at least one exit surface  09  is arranged in the plane. The at least two delimiting planes are preferably situated perpendicularly on the plane that includes the at least one exit surface  09 , preferably the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  of the at least four nozzle bars  04 . A delimiting plane of the at least two delimiting planes preferably delimits the at least one nozzle bar  04  in the transport direction T in a leading direction, and a delimiting plane of the at least two delimiting planes preferably delimits the at least one nozzle bar  04  in the transport direction T in a trailing direction. The area between the at least one nozzle bar  04  and the transport path of printing substrate  03  preferably describes a spatial area within the at least two delimiting planes. Preferably, the at least one cleaning device  18  or the at least one cleaning system  61 , within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 , is configured to enter into a functional connection with the at least one nozzle bar  04 , for example configured so as to clean the same. An element that is arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03  preferably enters into a functional connection with the at least one nozzle bar  04 . 
     For example, a cleaning device  18 , which is positioned in the usage position by way of the at least one guide system  19 , is assigned to the at least one print head  08  of a nozzle bar  04  that is arranged in the first service position, this being the cleaning position. Preferably, the at least one cleaning device  18  is configured to be movable and/or to move, in particular as a whole, at least orthogonally to the transverse direction A, preferably by way of the at least one guide system  19 . Preferably, in the at least one first service position of the at least one nozzle bar  04 , at least one cleaning device  18  that is arranged in the usage position is assigned to and/or can be assigned to and/or is situated opposite at least one respective exit surface  09  of at least one print head  08 , in particular a respective exit surface  09  of at least two, preferably at least three, and more preferably of at least four, print heads  08 . 
     The at least one cleaning device  18  is configured to be transferrable and/or to move from the storage position into the usage position, or vice versa, by the at least one guide system  19 , in particular along the at least one guide element  53 . The at least one cleaning device  18  is configured to be displaced, preferably in a rectilinear or linear manner, along the at least one guide element  53 . The at least one cleaning device  18  is configured to move and/or be movable and/or is moved along the at least one guide element  53  of the at least one guide system  19  from the at least one storage position into the at least one usage position, or vice versa. The at least one storage position and the at least one usage position are arranged along the at least one guide element  53 . The at least one storage position and the at least one usage position are spaced apart from one another at a distance of greater than zero. 
     In the first or the third service position, this being the cleaning position or the depot position, of the at least one nozzle bar  04 , the cleaning device  18  that is assigned to and/or arranged opposite the corresponding nozzle bar  04  is preferably configured as at least one locking element, for example in the form of a maintenance stop. In its first or third service position, the nozzle bar  04  comprising the at least one print head  08  is preferably pulled and/or pressed against the at least one cleaning device  18 , preferably as a result of the application of a force and/or, for example, by gravity. In this way, the first or third service position of the at least one nozzle bar  04  is preferably unambiguously defined. 
     The at least one nozzle bar  04  is preferably arranged in the first service position, this being the cleaning position, when the at least one cleaning device  18  is arranged in the at least one usage position, and when at least one cleaning element  31  is arranged in an operating position. The at least one nozzle bar  04  is preferably arranged in the third service position, this being the depot position, when the at least one cleaning device  18  is arranged in the at least one usage position, and when the at least one cleaning element  31  is arranged in a supply position. Preferably as an alternative, the at least one nozzle bar  04  is arranged in the idle position when the at least one cleaning device  18  is arranged in the at least one usage position, and when the at least one cleaning element  31  is arranged in the supply position. 
     The at least one cleaning device  18  comprises at least one cleaning unit  26 , in particular the at least one cleaning element  31 . The at least one cleaning device  18  preferably comprises at least one crossbar  22 , which is preferably configured as a collecting trough  22 . The crossbar  22  is preferably a mechanical carrier. 
     The at least one collecting trough  22  preferably has its longitudinal direction along its longest extension. The longitudinal direction of the at least one collecting trough  22  is preferably oriented parallel to the at least one nozzle bar  04 . The collecting trough  22  preferably has its longest extension in the y direction. The at least one collecting trough  22  preferably extends across the entire extension of the at least one nozzle bar  04  in the transverse direction A. The at least one collecting trough  22  is preferably connected to the at least one crossbar  54  of the at least one guide system  19 , and/or attached thereto, in the transverse direction A upstream and downstream from the at least one nozzle bar  04 . The at least one collecting trough  22  is preferably configured as collection container for liquid or dirt. The at least one collecting trough  22  preferably encompasses at least one U-profile. 
     The at least one cleaning unit  26  and preferably the at least one cleaning element  31  are configured to move and/or be movable along the longitudinal direction of the at least one collecting trough  22 , preferably along a cleaning guide  44 . Preferably, the at least one cleaning unit  26  and preferably the at least one cleaning element  31  are configured to move and/or be movable in or counter to the transverse direction A and/or the y direction. 
     For example, in particular when the at least one nozzle bar  04  comprises at least two rows of print heads  08  that are preferably arranged next to one another in the y direction, at least two cleaning elements  31 , preferably exactly as many cleaning elements  31  as there are rows of print heads  08 , are assigned to the at least one collecting trough  22  and/or arranged at or in the at least one collecting trough  22 . 
     The at least one cleaning element  31  preferably has the at least one supply position. 
     The at least one supply position of the at least one cleaning element  31  is preferably a position of the at least one cleaning element  31  when it is not functionally connected to the at least one nozzle bar  04 . The at least one supply position of the at least one cleaning element  31  preferably corresponds to a safekeeping position when the printing press is in an operating mode in which the at least one cleaning element  31  is not employed. 
     In the at least one supply position, the at least one cleaning element  31  is preferably arranged and/or is being arranged outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , for example established by the at least one printing substrate guide element  02  that is situated opposite the nozzle bar  04 . In the at least one supply position, the at least one cleaning element  31  is preferably arranged outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , preferably along the y direction and/or along the transverse direction A and/or along the longest edge of the at least one nozzle bar  04 . In the at least one supply position, the at least one cleaning element  31  is preferably arranged and/or is being arranged outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , preferably along the y direction and/or along the transverse direction A and/or along the longest side of the at least one nozzle bar  04 . The supply position of the at least one cleaning element  31  preferably corresponds to a position along the at least one collecting trough  22 , in particular along its longitudinal direction, outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . Preferably, the at least one fluid supply opening  38  of the at least one cleaning element  31  that is arranged in the supply position, preferably of the at least one cleaning device  18  arranged in the usage position, more preferably of the centroid of the delimitation of the fluid supply opening  38 , has a preferably third preferably relative distance and/or is arranged at the relative distance, preferably a distance in the y direction and/or in the transverse direction A, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one fluid supply opening  38  of the at least one cleaning element  31  arranged in the supply position, preferably of the centroid of the delimitation of the fluid supply opening  38 , with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is at least twice, preferably at least two point five times, more preferably at least three times, more preferably at least five times, as large as an extension in the transverse direction A of the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one cleaning device  18 . Preferably, the relative distance with respect to a first print head  08  of the at least one row of print heads  08  of the at least one nozzle bar  04  is determined, the print head  08  being arranged closest to the supply position. 
     The at least one cleaning element  31  is preferably configured to be movable and/or to move, along the y direction and/or along the transverse direction A, out of the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , so as to reach the at least one supply position. The at least one cleaning element  31  is preferably in the idle state in the at least one supply position. 
     The at least one cleaning element  31  preferably has at least one operating position. The at least one cleaning device  18  is preferably arranged in its usage position when the at least one cleaning element  31  is arranged in its operating position. 
     In at least one cleaning operating mode of the printing press, in particular when the at least one cleaning element  31  is configured to clean the at least one nozzle bar  04 , the at least one cleaning element  31  is preferably arranged in the at least one operating position. The at least one operating position of the at least one cleaning element  31  is preferably a position within the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , for example established by the at least one printing substrate guide element  02  that is situated opposite the nozzle bar  04 . The operating position preferably corresponds to a position along the at least one collecting trough  22 , in particular along its longitudinal direction, within the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . The at least one print head  08 , preferably the at least one exit surface  09  of the at least one print head  08 , of the at least one nozzle bar  04 , preferably of the at least one nozzle bar  04  of the at least four nozzle bars  04 , is preferably cleaned in a contactless manner by the at least one cleaning device  18 . The at least one print head  08 , preferably the at least one exit surface  09  of the at least one print head  08 , of the at least one nozzle bar  04 , preferably of the at least one nozzle bar  04  of the at least four nozzle bars  04 , is preferably cleaned in a contactless manner by the at least one cleaning device  18  comprising the at least one cleaning element  31 , which is arranged in the operating position, including the at least one fluid supply opening  38 . In the operating position, the at least one cleaning element  31  is preferably arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . Preferably, the at least one fluid supply opening  38  of the at least one cleaning element  31  that is arranged in the operating position, preferably of the at least one cleaning device  18  arranged in the usage position, more preferably of the centroid of the delimitation of the fluid supply opening  38 , has a preferably fourth preferably relative distance and/or is arranged at the relative distance, preferably a distance in the y direction and/or in the transverse direction A, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one fluid supply opening  38  of the at least one cleaning element  31  arranged in the operating position, preferably of the centroid of the delimitation of the fluid supply opening  38 , with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is no more than one time, preferably no more than zero point five times, as large as an extension in the transverse direction A of the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one cleaning device  18 . The relative distance is preferably less in the operating position than in the supply position. 
     The at least one cleaning element  31  is preferably configured to be movable and/or to move, along the y direction and/or along the transverse direction A, into the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , so as to reach the at least one operating position. The at least one cleaning element  31  is preferably in movement with respect to the cleaning device G in the at least one operating position. 
     The at least one cleaning element  31  is preferably arranged in the at least one operating position when it is functionally connected to the at least one nozzle bar  04 . The at least one cleaning device  18  preferably at least temporarily enters into a functional connection with the at least one nozzle bar  04 , preferably when the at least one nozzle bar  04  is arranged in the first service position, this being the cleaning position, and the at least one cleaning element  31  is arranged in the operating position. The at least one cleaning device  18 , in particular at least two, preferably all, cleaning elements  31  of the cleaning device  18  that are arranged in the operating position, preferably enter into a functional connection with at least two, and preferably all, nozzle bars  04 , the nozzle bars  04  preferably being arranged in the first service position at the same time. Preferably, further nozzle bars  04  of the printing unit  01  that are not to enter into a functional connection with the at least one cleaning device  18 , while preferably at least one nozzle bar  04  is functionally connected to the at least one cleaning element  31  of the at least one cleaning device  18 , are preferably arranged in the idle position or the depot position at this time. 
     The at least one cleaning device  18  has the at least one storage position and the at least one usage position. The at least one cleaning device  18  is moved by the at least one guide system  19  from the at least one storage position into the at least one usage position, or vice versa. The at least two cleaning devices  18  are configured to move and/or be movable along the at least one guide element  53  from the at least one storage position, in particular the storage position that is arranged outside the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 , into the at least one usage position, in particular a usage position that is arranged within the area between the at least one nozzle bar  04  and the transport path of at least one printing substrate  03 , or vice versa. The at least one cleaning device  18  is moved, preferably linearly displaced, along the at least one guide element  53  of the at least one guide system  19  from the at least one storage position into the at least one usage position, or vice versa, preferably along a direction along the shortest side of the at least one nozzle bar  04 . The at least one cleaning device  18  preferably comprises at least one drive. The at least one drive of the at least one cleaning device  18  is preferably configured to drive the movement of the at least one cleaning device  18  from the storage position into the usage position, or vice versa. 
     The at least one cleaning element  31  preferably has the at least one supply position and the at least one operating position. The at least one cleaning element  31  is preferably moved from the at least one supply position into the at least one operating position, or vice versa. In its at least one operating position, the at least one cleaning element  31  is preferably moved in or counter to the cleaning direction G in the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . 
     The at least one cleaning device  18  cleans the at least one print head  08 . The at least one cleaning device  18  at least temporarily cleans the at least one print head  08 . In the first service position, the at least one print head  08  is preferably cleaned by the at least one cleaning device  18 , in particular by the at least one cleaning element  31 . 
     The printing press, preferably the at least one printing unit  01 , preferably comprises at least one cleaning system  61 . The at least one cleaning system  61  preferably comprises at least one removal unit  63 . The at least one removal unit  63  preferably comprises at least one contact element  64 . Preferably, at least one removal unit  63  is in each case assigned to a nozzle bar  04  of the at least one printing unit  01  and/or at least temporarily enters into a functional connection with at least one nozzle bar  04 . The at least one cleaning system  61  preferably is configured to at least temporarily make direct contact with the at least one print head  08 , at least by way of the at least one contact element  64 . The at least one cleaning system  61  preferably is configured to make direct contact and/or makes direct contact with the at least one print head  08 , at least by way of the at least one contact element  64 . More preferably, the at least one cleaning system  61  comprises at least two removal units  63 . Preferably, a respective removal unit  63  in each case is configured to make contact in each case with at least one row of print heads  08  and/or all removal units  63  are preferably in each case configured to simultaneously make contact with a row of print heads  08 . Preferably, a respective removal unit  63  in each case makes contact with at least one row of print heads  08  and/or all removal units  63  preferably in each case simultaneously make contact with a row of print heads  08 . The at least one cleaning system  61  preferably makes direct contact with the at least one print head  08 , at least by way of the at least one contact element  64 . The at least one printing unit  01  preferably comprises the at least one cleaning system  61 , comprising at least two removal units  63 . Preferably, at least two nozzle bars  04 , preferably at least two nozzle bars  04  of the at least four nozzle bars  04 , are configured to make contact, and/or make contact, with at least one respective removal unit  63 . 
     The at least one cleaning system  61  preferably comprises at least one guide element  62 . The at least one cleaning system  61  preferably comprises at least two guide elements  62 , more preferably exactly two guide elements  62 . The at least one removal unit  63  is preferably configured to move and/or be movable along the at least one guide element  62 , along the longest edge of the at least one nozzle bar  04  and/or along the y direction. The at least one removal unit  63  is preferably configured to move and/or be movable and/or is moved along the at least one guide element  62 , along the longest side of the at least one nozzle bar  04  and/or along the y direction. The at least one removal unit  63  is preferably arranged along the at least one guide element  62 , along a longest side of the at least one nozzle bar  04  and/or along the y direction, in at least one supply position or in at least one operating position. The supply position and the operating position are preferably spaced apart from one another at a distance of greater than zero. The at least one guide element  62  is preferably configured as a bar and/or a rod and/or a rail and/or a linear guide. A longest extension of the at least one guide element  62 , preferably its longitudinal direction, preferably extends in the y direction and/or in the transverse direction A, that is, parallel to a longest extension of the at least one nozzle bar  04 . The at least one guide element  62  preferably enables rapid and secure guidance of the at least one removal unit  63 . The risk of at least one removal unit  63  tilting and, for example, thereby damaging the at least one exit surface, is preferably minimized. 
     Preferably, in the x direction, that is, preferably along the transport path of the printing substrate  03 , at least one of the respective guide elements  62  is arranged upstream, and at least one of the respective guide elements  62  is arranged downstream, from the at least one nozzle bar  04 . Preferably, in the x direction, that is, preferably along the transport path of the printing substrate  03 , at least one of respective guide element  62 , preferably exactly one respective guide element  62 , is arranged upstream from a first nozzle bar  04  of the printing unit  01 , and downstream from a last nozzle bar  04  of the printing unit  01 . For example, when the at least one printing substrate guide element  02  situated opposite the at least one nozzle bar  04  is configured as a cylinder or roller, at least one of the respective guide elements  62  is arranged along the circumference of the at least one printing substrate guide element  02  upstream from the at least one nozzle bar  04 , and at least one of the respective guide elements  62  is arranged along the circumference of the at least one printing substrate guide element  02  downstream from the at least one nozzle bar  04 . 
     The at least one removal unit  63  is preferably configured to be displaced and/or be displaceable, preferably in a linear manner, along the at least one guide element  62  of the at least one cleaning system  61 . The at least one removal unit  63  is preferably configured to move and/or be movable and/or is moved along the at least one guide element  62  in or counter to at least one direction, in particular the cleaning direction G and/or the transverse direction A and/or the y direction. The at least one removal unit  63  is preferably configured to move and/or be movable and/or is moved along the at least one guide element  62  from the at least one supply position into the at least one operating position, or vice versa. 
     The at least one guide element  62  is preferably configured to guide and/or move the at least one removal unit  63  in or counter to the cleaning direction G. Preferably, when the at least one removal unit  63  is arranged on at least one carrier  76  or connected to the at least one carrier  76 , the at least one guide element  62  is configured to guide and/or move the at least one carrier  76  in or counter to the cleaning direction G. 
     Preferably, the at least one removal unit  63 , more preferably the at least one contact element  64 , has the at least one supply position. 
     The at least one supply position of the at least one removal unit  63  is preferably a position of the at least one removal unit  63  when it is not functionally connected to the at least one nozzle bar  04 . The at least one supply position of the at least one removal unit  63  preferably corresponds to a safekeeping position of the at least one removal unit  63  when the printing press is in an operating mode in which the at least one removal unit  63  is not employed. 
     In the at least one supply position, the at least one removal unit  63  is preferably arranged and/or is being arranged outside an area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , for example established by the at least one printing substrate guide element  02  that is situated opposite the nozzle bar  04 . 
     In a preferred embodiment, for example shown in  FIG.  10    to  FIG.  12   a   , in the at least one supply position, the at least one removal unit  63  is preferably arranged and/or is being arranged outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , preferably along the y direction and/or along the transverse direction A, preferably along the longest side of the at least one nozzle bar  04 . The at least one removal unit  63  is preferably arranged in the at least one supply position along a longest edge of the at least one nozzle bar  04  and/or along the y direction, outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . In the at least one supply position, the at least one removal unit  63  is preferably arranged and/or is being arranged along the longest side of the at least one nozzle bar  04  and/or along the y direction, outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . The supply position preferably corresponds to a position along the at least one guide element  62 , in particular along its longitudinal direction, outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . The at least one removal unit  63  is preferably configured to be movable and/or to move, along the y direction and/or along the transverse direction A, out of the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , so as to reach the at least one supply position. Preferably, the at least one contact element  64  of the at least one removal unit  63  that is arranged in the supply position, more preferably at least one contact zone, has a preferably fifth preferably relative distance and/or is arranged at the relative distance, preferably a distance in the y direction and/or in the transverse direction A, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one contact element  64  of the at least one removal unit  63  arranged in the supply position, more preferably of the at least one contact zone, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is at least twice, preferably at least two point five times, more preferably at least three times, more preferably at least five times, as large as an extension in the transverse direction A of the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one removal unit  63 . Preferably, the relative distance with respect to a first print head  08  of the at least one row of print heads  08  of the at least one nozzle bar  04  is determined, the print head  08  being arranged closest to the supply position. 
     For example, in an alternative embodiment, for example shown in  FIG.  15    to  FIG.  17   c   , the supply position of the at least one removal unit  63  is preferably arranged upstream or downstream from the at least one nozzle bar  04  of the printing unit  01 , in the x direction, that is, preferably along the transport path of the printing substrate  03 . The at least one cleaning system  61  for this purpose preferably comprises at least one pivot element  81 , preferably at least two pivot elements  81 , forming a pivot axis of the at least one removal unit  63  and/or of the at least one guide element  62 . The at least one removal unit  63  and/or the at least one guide element  62  are preferably configured to pivot about the at least one pivot element  81 . The at least one removal unit  63  is preferably transferred from the supply position into the operating position by pivoting about the at least one pivot element  81 . 
     The at least one removal unit  63  is preferably in the idle state in the at least one supply position. 
     Preferably, in particular when the at least one removal unit  63  is arranged on the at least one carrier  76  and/or connected to the at least one carrier  76 , the at least one carrier  76  has the at least one supply position and/or is arranged and/or can be arranged at least temporarily in the at least one supply position. 
     Preferably, the at least one removal unit  63 , more preferably the at least one contact element  64 , has the at least one operating position. For example, the at least one removal unit  63  is arranged in the at least one operating position in  FIG.  12   b   . Preferably, the at least one removal unit  63 , more preferably the at least one contact element  64 , has the at least one supply position and the at least one operating position. 
     Preferably, in particular when the at least one removal unit  63  is arranged on the at least one carrier  76  and/or connected to the at least one carrier  76 , the at least one carrier  76  has the at least one operating position and/or is arranged and/or can be arranged, at least temporarily, in the at least one operating position. Preferably, at least two removal units  63  are arranged jointly on the at least one carrier  76 . The at least one carrier  76  in particular then preferably has the at least one supply position and the at least one operating position. 
     In at least one cleaning operating mode of the printing press, in particular when the at least one removal unit  63  is configured to clean the at least one nozzle bar  04 , the at least one removal unit  63  is preferably arranged in the at least one operating position. The at least one operating position of the at least one removal unit  63  is preferably a position within the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , for example established by the at least one printing substrate guide element  02  that is situated opposite the nozzle bar  04 . The operating position preferably corresponds to a position along the at least one guide element  62 , in particular along its longitudinal direction, within the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . Preferably, in the at least one operating position, the at least one removal unit  63  is at least temporarily in motion with respect to the cleaning direction G. Preferably, the at least one contact element  64  of the at least one removal unit  63  that is arranged in the operating position, more preferably the at least one contact zone, has a preferably sixth preferably relative distance and/or is arranged at the relative distance, preferably a distance in the y direction and/or in the transverse direction A, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08 . Preferably, the preferably relative distance of the at least one contact element  64  of the at least one removal unit  63  arranged in the operating position, more preferably of the at least one contact zone, with respect to the at least one opening of the at least one exit surface  09  of the at least one print head  08  is no more than one time, preferably no more than zero point five times, as large as an extension in the transverse direction A of the at least one exit surface  09  of the at least one print head  08  of the at least one nozzle bar  04  to be cleaned by the at least one removal unit  63 . The relative distance is preferably less in the operating position than in the supply position. 
     In the preferred embodiment, for example shown in  FIG.  10    to  FIG.  12   b   , the at least one removal unit  63  is preferably configured to be movable and/or to move into the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , preferably along the y direction and/or along the transverse direction A, preferably along the longest side of the at least one nozzle bar  04 , so as to reach the at least one operating position. 
     In the alternative embodiment, for example shown in  FIG.  15    to  FIG.  17   c   , the at least one removal unit  63  is preferably configured to pivot about the at least one pivot element  81  from the supply position, that is, an area outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , into the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03  so as to reach the at least one operating position. 
     The at least one removal unit  63  is preferably arranged in the at least one operating position when it is functionally connected to the at least one nozzle bar  04 . The at least one cleaning system  61  preferably enters at least temporarily into a functional connection with the at least one nozzle bar  04 , preferably when the at least one nozzle bar  04  is arranged in the second service position, this being the intensive cleaning position, and the at least one removal unit  63  is arranged in the operating position. The at least one cleaning system  61 , in particular at least two removal units  63  of the cleaning system  61  that are arranged in the operating position, preferably enter into a functional connection with at least two, preferably all, nozzle bars  04 , the nozzle bars  04  preferably being arranged in the second service position at the same time. Preferably, further nozzle bars  04  of the printing unit  01  that are not to enter into a functional connection with the at least one cleaning system  61 , while preferably at least one nozzle bar  04  is functionally connected to the at least one cleaning system  61 , are preferably arranged in the idle position at this time. 
     The at least one cleaning system  61  is preferably configured to clean at least one print head  08  of the at least one nozzle bar  04  that is arranged in the second service position by way of at least temporary direct contact. Preferably, the at least one print head  08 , preferably its at least one exit surface  09  and/or its at least one bearing surface  11  and/or the at least one positioning gap  07 , of the at least one nozzle bar  04  arranged in the second service position, this being the intensive cleaning position, are at least temporarily in direct contact with at least one component of the cleaning system  61  that is arranged in the operating position, in particular with the at least one contact element  64  of the at least one removal unit  63  that is arranged in the operating position. 
     The at least one removal unit  63  preferably has the at least one supply position and the at least one operating position. The at least one removal unit  63  is preferably configured to be displaced and/or be displaceable along the at least one guide element  62  of the at least one cleaning system  61 . The at least one removal unit  63  is preferably configured to move and/or be movable and/or is moved along the at least one guide element  62  in or counter to the at least one cleaning direction G, preferably in or counter to the y direction and/or preferably in or counter to the transverse direction A. The at least one cleaning system  61  preferably comprises at least one drive. The at least one drive of the at least one cleaning system  61  is preferably configured to drive the movement of the at least one removal unit  63 , in particular along the at least one guide element  62 . 
     The at least one removal unit  63  is preferably moved from the at least one supply position into the at least one operating position, or vice versa. Preferably, the at least one removal unit  63  is preferably configured to be displaced and/or be displaceable along the at least one guide element  62 , preferably in the cleaning direction G and/or y direction, of the at least one cleaning system  61 , while the at least one nozzle bar  04  is arranged in the at least one service position. The at least one removal unit  63  is preferably configured to move and/or be movable along the at least one guide element  62  from the at least one supply position that is arranged outside the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 , into the at least one operating position that is arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 , or vice versa. In particular, the at least one nozzle bar  04  is at idle in the process. 
     The at least one cleaning system  61  preferably at least temporarily cleans the at least one print head  08 . In the second service position, the at least one print head  08  is preferably cleaned by the at least one cleaning system  61 , in particular by the at least one removal unit  63 . In the at least one operating position, the at least one removal unit  63  is preferably configured to move and/or be movable in or counter to at least one cleaning direction G, preferably in or counter to the y direction, preferably along the at least one guide element  62 , for example driven by the at least one drive of the cleaning system  61 . In a cleaning step in the at least one operating position, the at least one removal unit  63  is preferably moved in or counter to the cleaning direction G, preferably in or counter to the y direction, preferably along the at least one guide element  62 . The at least one print head  08  of the at least one nozzle bar  04 , preferably of the at least one nozzle bar  04  of the at least four nozzle bars  04 , is preferably cleaned by the at least one cleaning system  61  comprising the at least one removal unit  63 , which is arranged in the at least one operating position, comprising the at least one contact element  64  configured as a wiping cloth  64 . In the at least one operating position, the at least one removal unit  63  is preferably arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . 
     More preferably, the at least one nozzle bar  04  comprises the at least two print heads  08 . The at least two print heads  08  are preferably arranged in at least two different rows. The at least one cleaning system  61  preferably cleans the at least two rows of the print heads  08  of the at least one nozzle bar  04  simultaneously. 
     The at least one printing unit  01  comprises the at least one cleaning device  18 . The at least one cleaning device  18  is configured to clean the at least one exit surface  09  and/or the at least one bearing surface  11  of the at least one print head  08  of the at least one nozzle bar  04 . Preferably in addition or as an alternative, the at least one cleaning device  18  cleans the at least one positioning gap  07 . Preferably, at least one respective cleaning device  18  is assigned to each nozzle bar  04  of a printing unit  01 . 
       FIG.  5   a   , by way of example, shows a corresponding cleaning device  18  in the usage position, which is preferably assigned to a nozzle bar  04  in the first service position. For the sake of clarity, only four print heads  08  of the relevant nozzle bar  04  are shown. 
     The at least one cleaning device  18  preferably comprises at least one cleaning guide  44  and/or the at least one cleaning drive  21  and/or the at least one collecting trough  22  and/or at least one support system  23 ;  24  and/or at least one cleaning unit  26 , preferably at least one cleaning unit  26  per row of print heads  08  in the y direction of the relevant nozzle bar  04 . 
     The at least one support system  23 ;  24  is preferably in each case configured as at least one positioning aid  23  and/or as at least one cleaning aid  24 . 
     In a preferred embodiment, the at least one cleaning device  18  comprises at least two cleaning elements  31 . In this way, the at least one cleaning device  18  is preferably configured to clean, in particular simultaneously, at least two print heads  08 , in particular a multiplicity of print heads  08 , of the at least one nozzle bar  04 . For example, the at least two print heads  08  are preferably simultaneously cleaned in different rows, preferably in at least two rows, of print heads  08  of the at least one nozzle bar  04 . 
     Preferably, the at least one cleaning device  18  has an extension in the transverse direction A that is at least as large as the working width of the at least one nozzle bar  04  in the transverse direction A. In this way, preferably the at least two print heads  08 , preferably all exit surfaces  09  of all print heads  08 , more preferably in addition or as an alternative to the exit surfaces  09 , the bearing surfaces  11  of the print heads  08 , of the at least one nozzle bar  04  are cleaned in one operation. Preferably, the at least one cleaning device  18 , in the transport direction T of the printing substrate  03 , has an extension that is at least as large as the extension of the surface of the at least one print head  08  of the at least one nozzle bar  04  in the transport direction T. Preferably, the at least one cleaning device  18 , in the transport direction T of the printing substrate  03 , has an extension that is at least as large as the extension of a projection of the surface of the at least one print head  08  of the at least one nozzle bar  04  in the plane of the exit surface  09  in the transport direction T. More preferably, at least the at least one cleaning element  31 , in the transport direction T of printing substrate  03 , has an extension that is at least as large as the extension of a projection of the surface of the at least one print head  08  of the at least one nozzle bar  04  into the plane of the exit surface  09  in the transport direction T. Preferably, the extension of the at least one cleaning device  18  in the transport direction T is at least greater than the extension of at least two rows of print heads  08  of the at least one nozzle bar  04  in the transport direction T. Preferably, the at least one cleaning device  18  thus at least temporarily encloses the at least two rows of print heads  08  of the nozzle bar  04  arranged in the first or third service position. 
     The at least one cleaning unit  26  is preferably arranged so as to be movable and/or move along the cleaning guide  44 , for example by means of the cleaning drive  21 . More preferably, the at least one cleaning unit  26  is arranged so as to be movable and/or is moved in and/or counter to a cleaning direction G, in particular along the cleaning guide  44 . The at least one collecting trough  22  is preferably arranged so as to at least partially enclose the at least one cleaning unit  26 . More preferably, the collecting trough  22  is arranged such that the collecting trough  22  at least partially encloses the cleaning unit  26  and the at least one print head  08  of the relevant nozzle bar  04  which is arranged in the first service position or third service position. 
     The at least one cleaning unit  26  preferably comprises at least one mounting element  28 , preferably at least two mounting elements  28 , and/or at least one force element  29  and/or at least one carrier  27  and/or the at least one cleaning element  31 . Preferably, the at least one mounting element  28 , preferably at least two mounting elements  28 , and/or the at least one force element  29  and/or the at least one carrier  27  and/or the at least one cleaning element  31  are preferably fixedly connected to one another within the corresponding cleaning unit  26 . 
     The at least one mounting element  28  is, in particular the at least two mounting elements  28  are, preferably in direct contact with the at least one force element  29 . The at least one force element  29  is, for example, configured as a bellows and/or hollow object and/or spring, and is preferably settable in terms of its extension and/or dimension in the z direction, preferably in a direction whose main component corresponds to the z direction. The at least one carrier  27  is preferably configured as a base body and/or preferably carries the at least one mounting element  28 , preferably at least two mounting elements  28 , and/or the at least one force element  29  and/or the at least one cleaning element  31  of the corresponding cleaning unit  26 . The at least one cleaning element  31  is preferably arranged so as to be in direct contact with at least one mounting element  28 , preferably at least two mounting elements  28 . Preferably, the extension and/or dimension of the cleaning unit  26  in the z direction, more preferably in a direction whose main component corresponds to the z direction, can be set and/or changed and/or moved by way of a change of the extension and/or dimension of the at least one force element  29  of the relevant cleaning unit  26 . As a result of this movability, the at least one cleaning element  31  can preferably be brought in contact and/or moved out of contact with other components, wherein in particular the at least one print head  08  and/or the at least one support system  23 ;  24  could be such components. 
     In a preferred embodiment, the at least one cleaning unit  26  comprises the at least one cleaning element  31 , which is connected to the at least one carrier  27  by way of the at least one force element  29 , preferably by way of at least four force elements  29 , for example by way of exactly four force elements  29 . Preferably, the at least one force element  29 , in particular the at least four force elements  29 , are each configured as a spring. Preferably, the at least one cleaning element  31  is preferably floatingly supported and/or attached in the at least one carrier  27 , which is preferably configured as a base body, by the at least one force element  29 . This preferably allows the contact pressure to be set precisely and easily, which the assigned nozzle bar  04  preferably exerts, when lowered into the service position and/or when arranged, in the service position, on the at least one cleaning element  31 , in particular on at least one sliding point  32  of the cleaning element  31 . 
     Preferably, the cleaning device  18  comprises at least one positioning aid  23  that is different from each print head  08 , which preferably includes at least one contact surface that is oriented in the same direction as the at least one bearing surface  11  and/or exit surface  09  of the at least one print head  08 . Preferably, the at least one contact surface of the positioning aid  23 , preferably with respect to the cleaning direction G, is situated following or spaced apart from the at least one bearing surface  11  of a relevant print head  08 . More preferably, the contact surface of the positioning aid  23  has an identical component in the z direction as the exit surface  09  of a print head  08  to be cleaned by way of the corresponding cleaning element  31 . In particular when direct contact is provided between the at least one cleaning element  31  and the exit surface  09  of a print head  08  of the relevant nozzle bar  04 , the contact surface of the positioning aid  23  is oriented in the same direction as the at least one exit surface  09 . If, for example, direct contact is provided between the at least one cleaning element  31  and the exit surface  09  of a print head  08  of the relevant nozzle bar  04 , the cleaning element  31  is preferably configured as a contact element, for example as a wiper. In particular when only indirect contact is provided between the at least one cleaning element  31  and the exit surface  09  of a print head  08  of the relevant nozzle bar  04 , the contact surface of the positioning aid  23  is oriented in the same direction as the at least one bearing surface  11 , in particular the at least one spacer surface  11 . The at least one positioning aid  23  is preferably arranged in such a way that the at least one cleaning element  31  is arranged so as to be unambiguously positionable with respect to at least one print head  08 , which is in particular to be cleaned. 
     The at least one cleaning device  18  preferably comprises at least one cleaning aid  24 . The cleaning aid  24  is preferably configured in such a way that the at least one cleaning element  31  can be cleaned. The cleaning aid  24  preferably comprises at least one spraying device and/or at least one wiping device. 
     The at least one cleaning element  31  is preferably configured as a cleaning head  31 . The cleaning element  31  is preferably fixedly connected to the at least one mounting element  28  and/or the at least one carrier  27  of the relevant cleaning device  18 , in particular of the relevant cleaning unit  26 . The at least one cleaning element  31  is preferably arranged to be movable in and/or counter to the cleaning direction G. 
     The cleaning head  31  preferably comprises at least one fluid input  38  and at least one fluid removal opening  39 ;  41 . The at least one fluid input  38  is more preferably configured as at least one fluid input  38  for supplying cleaning liquid. The at least one fluid removal opening  39 ;  41  is more preferably configured as at least one fluid removal opening  39 ;  41  for cleaning liquid and/or dirt. More preferably, the cleaning head  31  includes at least two fluid removal openings  39 ;  41 , wherein in each case a first fluid removal opening  39  is preferably configured as a fluid discharge  39  and/or wherein in each case a second fluid removal opening  41  is preferably configured as a fluid extraction  41 . Preferably, the at least one first fluid removal opening  39  at least partially, and more preferably completely, surrounds the at least one fluid input  38  in a plane. 
     If, for example, the cleaning head  31  is arranged so as to be in direct or indirect contact with the at least one print head  08 , for example, the at least one fluid input  38  is configured to dispense at least one cleaning fluid, in particular a cleaning agent, in the immediate vicinity of the exit surface  09  of the at least one print head  08  and/or of a positioning gap  07 , and the at least one fluid removal opening  39 ;  41  is configured to extract the at least one cleaning fluid again, likewise in the immediate vicinity of the exit surface  09  of the at least one print head  08  and/or of a positioning gap  07 . For this purpose, the cleaning head  31  is preferably brought so close to the at least one print head  08  that a cleaning gap is formed between the cleaning head  31  on the one hand, and the exit surface  09  of the print head  08  on the other hand, through which the fluid, in particular the cleaning liquid, flows and, as a result, the exit surface  09  of the at least one print head  08  and/or a positioning gap  07  are cleaned and/or can be cleaned. 
     The at least one cleaning head  31  preferably includes at least one sliding point  32  that is in particular intended for contact with the at least one print head  08 , wherein the sliding point  32  is preferably configured as a sliding surface  32 . The at least one sliding point  32  is preferably configured for at least partial contact with at least a portion of at least one bearing surface  11  of the at least one print head  08 , which more preferably is configured as at least one spacer surface  11 . 
     The at least one cleaning head  31  preferably comprises at least one ramp  33 ;  34 . More preferably, the cleaning head  31  comprises at least one first ramp  33  and at least one second ramp  34 . This preferably facilitates a positioning of the at least one cleaning element  31  at the at least one print head  08  and/or the movement of the at least one cleaning element  31  along the at least one nozzle bar  04 , for example during a cleaning process. Preferably, the at least one cleaning element  31  can be arranged in at least one first position and/or can be arranged in at least one second position, wherein the first position of the cleaning element  31  is arranged spaced apart from the second position of the cleaning element  31 , preferably along the cleaning direction G. For example, the first ramp  33  and/or the second ramp  34  are embodied as oblique surfaces. 
     The first ramp  33  is preferably configured as an input ramp  33 . The first ramp  33  is preferably arranged so as reduce the distance between a reference point of the first ramp  33  and the print head  08  to be cleaned. The reference point of the first ramp  33  is preferably a point of the first ramp  33  that is arranged perpendicularly to the print head  08  to be cleaned. In the first position of the cleaning element  31 , the first ramp  33  preferably has a first distance with respect to a print head  08  to be cleaned, preferably with respect to at least one exit surface  09  and/or spacer surface  11  to be cleaned, at the reference point of the first ramp  33 . In the second position of the cleaning element  31 , the first ramp  33  preferably has a second distance with respect to a print head  08  to be cleaned, preferably with respect to at least one exit surface  09  and/or spacer surface  11  to be cleaned, at the reference point of the first ramp  33 , wherein the second distance between the reference point of the first ramp  33  and the print head  08  to be cleaned is less than the first distance between the reference point of the first ramp  33  and the print head  08  to be cleaned. 
     The second ramp  34  is preferably configured as an exit ramp  34 . The second ramp  34  is preferably arranged so as increase the distance between a reference point of the second ramp  34  and the print head  08  to be cleaned. The reference point of the second ramp  34  is preferably a point of the second ramp  34  that is arranged perpendicularly to the print head  08  to be cleaned. In the first position of the cleaning element  31 , the second ramp  34  preferably has a first distance with respect to a print head  08 , which is in particular to be cleaned, preferably with respect to at least one exit surface  09  and/or spacer surface  11  to be cleaned, at the reference point of the second ramp  34 . In the second position of the cleaning element  31 , the second ramp  34  preferably has a second distance with respect to a print head  08 , which is in particular to be cleaned, preferably with respect to at least one exit surface  09  and/or spacer surface  11  to be cleaned, at the reference point of the second ramp  34 , wherein the second distance between the reference point of the second ramp  34  and the print head  08 , which is in particular to be cleaned, is greater than the first distance between the reference point of the second ramp  34  and the print head  08 , which is in particular to be cleaned. 
     As an alternative or in addition, the at least one print head  08  and/or the at least one cleaning head  31  comprise at least one guide device  36 . This guide device  36  is preferably configured as a guide surface  36 , whose surface normal has at least one component that is orthogonal to the z direction and to the cleaning direction G. The at least one guide surface  36  of a cleaning head  31  preferably directly abuts at least one sliding surface  32  of the respective cleaning head  31 . The at least one guide device  36  is preferably arranged such that the cleaning head  31  can be positioned and/or is positioned with respect to a direction that is oriented parallel to the x direction and/or orthogonal to the cleaning direction G and orthogonal to the z direction in a tolerance range or an exact position. 
     The cleaning head  31  preferably includes at least one cleaning area  37 . The at least one cleaning area  37  preferably includes the at least one fluid input  38 , preferably the at least one fluid input  38  configured as at least one fluid supply opening  38 . The at least one cleaning area  37  preferably includes the at least one fluid input  38  and the at least one fluid removal opening  39 ;  41 . More preferably, the cleaning area  37  in each case includes the at least one fluid input  38  and/or the at least one fluid discharge  39  and/or the at least one fluid extraction  41 . The at least one fluid removal opening  39 ;  41  is preferably in each case connected to at least one trough for removing, for example, cleaning agents and/or dirt and/or particles. The at least one fluid input  38  is preferably connected to a source of cleaning agent. The fluid input  38  is preferably configured as a fluid supply opening  38  within the cleaning area  37 . The at least one cleaning area  37  is preferably arranged between the at least one first ramp  33  and the at least one second ramp  34 . In particular, the at least one first ramp  33  is arranged upstream from the at least one cleaning area  37  in the cleaning direction G. The at least one second ramp  34  is preferably arranged downstream from the at least one cleaning area  37  in the cleaning direction G. The first ramp  33  preferably inclines from an outer edge of the cleaning element  31  to the at least one cleaning area  37 . The second ramp  34  preferably inclines from an outer edge of the cleaning element  31  to the at least one cleaning area  37 . The slopes of the first ramp  33  and of the second ramp  34  are preferably oriented opposite one another. 
     The fluid supply opening  38  preferably has at least one delimitation of the fluid supply opening  38  in a plane of the surface of the cleaning area  37 , preferably orthogonal to the z direction, with a centroid. More preferably, the delimitation of the fluid supply opening  38  includes at least one first delimiting point, which is arranged with the centroid in alignment with respect to the cleaning direction G. Preferably, the delimitation of the fluid supply opening  38  includes at least one second delimiting point, which is arranged with the centroid in alignment with respect to a direction that is orthogonal to the cleaning direction G. The delimitation of the fluid supply opening  38  preferably includes at least one third delimiting point, which is arranged on the delimitation of the fluid supply opening  38  in an extension of a stretch from the first delimiting point to the centroid. The delimitation of the fluid supply opening  38  preferably includes at least one fourth delimiting point, which is arranged on the delimitation of the fluid supply opening  38  in an extension of a stretch from the second delimiting point to the centroid. The first delimiting point and the second delimiting point and the third delimiting point and the fourth delimiting point are each preferably positioned spaced apart from one another by a distance of greater than zero on the delimitation of the fluid supply opening  38 . The distance between the first delimiting point and the third delimiting point on the delimitation of the fluid supply opening  38  is preferably less than the distance between the second delimiting point and the fourth delimiting point on the delimitation of the fluid supply opening  38 . A longitudinal direction of the fluid supply opening  38  is preferably at least partially orthogonal to a straight line between the first delimiting point and the center of gravity of the delimitation of the fluid supply opening  38 . In other words, for example, the at least one fluid supply opening  38 , in particular the delimitation of the fluid supply opening  38 , preferably has the longitudinal direction of the fluid supply opening  38  and a transverse direction of the fluid supply opening  38  in the plane spanned by the x direction and the y direction, and/or orthogonal to the z direction. The extension of the fluid supply opening  38  preferably differs in its longitudinal direction and in its transverse direction. The fluid supply opening  38 , in particular the delimitation of the fluid supply opening  38 , preferably has a maximum extension in its longitudinal direction. The extension of the fluid supply opening  38 , in particular the delimitation of the fluid supply opening  38 , is preferably less in the transverse direction of the fluid supply opening  38  than in its longitudinal direction. 
     In an exemplary embodiment, a cleaning area  37  includes at least two fluid supply openings  38 , each having a delimitation of the respective fluid supply opening  38  in a plane of the surface of the cleaning area  37 . Each of the at least two fluid supply openings  38  has a centroid, wherein the centroids of the fluid supply openings  38  are preferably arranged on a straight line. The straight line of the at least two centroids of the fluid supply openings  38  is preferably arranged at least partially orthogonally to the cleaning direction G and orthogonally to the z direction. 
     Preferably, a tangent at the first delimiting point of the delimitation of the fluid supply opening  38  is preferably arranged at least partially orthogonally to the cleaning direction G and orthogonally to the z direction. The tangent at the first delimiting point of the delimitation of the fluid supply opening  38  preferably has a plane angle of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. The tangent at the first delimiting point of the delimitation of the fluid supply opening  38  is preferably parallel to a plane that is spanned at the position of the positioning gap  07 , for example shifted along the y direction, by the z direction and at least one direction of the shortest delimitation of a respective exit surface  09 , which is spanned in a plane of the x direction and y direction, of the print head  08  of the relevant nozzle bar  04  to be cleaned, which delimits the positioning gap  07 . 
     The tangent at the first delimiting point of the delimitation of the fluid supply opening  38  is preferably parallel to a longitudinal direction of the fluid supply opening  38 , in particular in the case of a fluid supply opening  38  that, for example, is configured to be elongated and/or oval and/or slot-shaped and/or as a groove and/or in a shape other than circular. More preferably, the longitudinal direction of the fluid supply opening  38  is oriented parallel to at least one positioning gap  07  of the assigned nozzle bar  04 . The longitudinal direction of the fluid supply opening  38  is preferably situated in a plane that is spanned by the x direction and the y direction. Preferably, the fluid supply opening  38  is configured as a groove and/or in an elongated and/or oval and/or slot-shaped manner, preferably in the plane orthogonal to the z direction. 
     A groove preferably has at least two longitudinal sides that are parallel to one another. The longitudinal direction of the fluid supply opening  38  preferably has a preferably plane angle, in particular an opening angle  47 , of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. In other words, this means, for example, that the longitudinal direction of the at least one fluid supply opening  38  has an identical oblique position with respect to the longitudinal direction of the at least one positioning gap  07 , preferably by the opening angle  47  with respect to the cleaning direction G. In particular, the opening angle  47  thus preferably corresponds to the at least partially diagonal overlap in the x direction of the at least two print heads  08  that are arranged next to one another, and in particular adjacent to one another. From this, it is apparent, for example, that the opening angle  47  is preferably acute or obtuse. This acute or obtuse configuration of the opening angle  47  preferably matches the at least partially diagonal overlap in the x direction of the at least two print heads  08  that are arranged next to one another and/or the orientation of the longitudinal direction of the at least one positioning gap  07 . 
     In a preferred embodiment, the fluid supply opening  38  is oriented parallel to at least one positioning gap  07  of the assigned nozzle bar  04 . More preferably, the fluid supply opening  38  is preferably oriented parallel to the at least one positioning gap  07  between at least two print heads  08 , which are in particular to be cleaned, preferably within a row, in the y direction of a nozzle bar  04 . More preferably, the tangent at the first delimiting point of the delimitation of the fluid supply opening  38  is oriented parallel to at least one positioning gap  07  of the assigned nozzle bar  04 . This allows, for example, cleaning agent to optimally enter the positioning gap  07 . 
     The fluid discharge  39  is preferably arranged, in at least one plane, at least partially around the fluid supply opening  38 . More preferably, the fluid discharge  39  is arranged, in at least one plane, completely around the fluid supply opening  38 . The aforementioned plane is preferably spanned by the x direction and the y direction. The fluid discharge  39  is preferably configured so as to allow to discharge, and/or to discharge, for example, cleaning agent and/or dirt and/or particles, which, for example, adhere to and/or remain as residue at the respective exit surface  09  and/or the respective bearing surface  11 , of a relevant print head  08 . 
     The fluid discharge  39  preferably has at least one delimitation of the fluid discharge  39  in a plane of the surface of the cleaning area  37 , preferably orthogonal to the z direction, with a centroid. More preferably, the delimitation of the fluid discharge  39  includes at least one fifth delimiting point, which is arranged with the centroid of the delimitation of the fluid discharge  39  in alignment with respect to the cleaning direction G. Preferably, the delimitation of the fluid discharge  39  includes at least one sixth delimiting point, which is arranged with the centroid in alignment with respect to a direction that is orthogonal to the cleaning direction G. Preferably, the delimitation of the fluid discharge  39  includes at least one seventh delimiting point, which is arranged on the delimitation of the fluid discharge  39 , in an extension of a stretch from the fifth delimiting point to the centroid. Preferably, the delimitation of the fluid discharge  39  includes at least one eighth delimiting point, which is arranged on the delimitation of the fluid discharge  39 , in an extension of a stretch from the sixth delimiting point to the centroid. The fifth delimiting point and the sixth delimiting point and the seventh delimiting point and the eighth delimiting point are each preferably positioned spaced apart from one another by a distance of greater than zero on the delimitation of the fluid discharge  39 . The distance between the fifth delimiting point and the seventh delimiting point on the delimitation of the fluid discharge  39  is preferably less than the distance between the sixth delimiting point and the eighth delimiting point on the delimitation of the fluid discharge  39 . A longitudinal direction of the fluid discharge  39  is preferably at least partially orthogonal to a straight line between the fifth delimiting point and the center of gravity of the delimitation of the fluid discharge  39 . In other words, for example, the at least one fluid discharge  39 , in particular the delimitation of the fluid discharge  39 , preferably has the longitudinal direction of the fluid discharge  39  and a transverse direction of the fluid discharge  39  in the plane spanned by the x direction and the y direction, and/or orthogonal to the z direction. The extension of the fluid discharge  39  is preferably different in its longitudinal direction and in its transverse direction. The fluid discharge  39 , in particular the delimitation of the fluid discharge  39 , preferably has a maximum extension in its longitudinal direction. Preferably, the extension of the fluid discharge  39 , in particular the delimitation of the fluid discharge  39 , is less in the transverse direction of the fluid discharge  39  than in its longitudinal direction. 
     More preferably, a tangent at the fifth delimiting point of the delimitation of the fluid discharge  39  is at least partially orthogonal to the cleaning direction G and orthogonal to the z direction and, additionally or alternatively, parallel to the corresponding tangent at the first delimiting point of the delimitation of the respective fluid supply opening  38 . In addition or as an alternative, the fluid discharge  39  is preferably oriented at least partially orthogonal to the cleaning direction G and orthogonal to the z direction and/or parallel to at least one positioning gap  07  of the assigned nozzle bar  04 . The tangent at the fifth delimiting point of the delimitation of the fluid discharge  39  is preferably oriented parallel to the at least one positioning gap  07  of the assigned nozzle bar  04 , in particular in a plane of the surface of the cleaning area  37 . The tangent at the fifth delimiting point of the delimitation of the fluid discharge  39 , which is arranged at least partially orthogonal to the cleaning direction G and orthogonal to the z direction, preferably has a plane angle of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. 
     The tangent at the fifth delimiting point of the delimitation of the fluid discharge  39  is preferably parallel to a longitudinal direction of the fluid discharge  39 , in particular in the case of a fluid discharge  39  that, for example, is configured in an elongated and/or oval and/or slot-shaped manner and/or as a groove and/or trapezoid and/or in a shape other than circular. Preferably, the fluid discharge  39  is configured in a trapezoidal and/or groove-shaped manner and/or as a parallelogram, preferably in the plane orthogonal to the z direction. More preferably, the longitudinal direction of the fluid discharge  39  is oriented parallel to at least one positioning gap  07  of the assigned nozzle bar  04 . The longitudinal direction of the fluid discharge  39  preferably has a preferably plane angle, in particular a discharge angle  48 , of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. In other words, this means, for example, that the longitudinal direction of the at least one fluid discharge  39  has an identical oblique position with respect to the longitudinal direction of the at least one positioning gap  07 , preferably by the discharge angle  48  with respect to the cleaning direction G. In particular, the discharge angle  48  thus corresponds to the at least partially diagonal overlap in the x direction of the at least two print heads  08  that are arranged next to one another, in particular adjacent to one another. From this, it is apparent, for example, that the discharge angle  48  is preferably acute or obtuse. This acute or obtuse configuration of the discharge angle  48  preferably matches the at least partially diagonal overlap in the x direction of the at least two print heads  08  arranged next to one another and/or the orientation of the longitudinal direction of the at least one positioning gap  07 . This preferably enables optimal extraction from the at least one positioning gap  07 . 
     For example, a strong negative pressure can be applied to the at least one fluid extraction  41 . The fluid extraction  41  is preferably configured to remove at least such cleaning fluid and/or such dirt which has remained after at least one extraction by means of the at least one fluid extraction  39 . 
     The at least one fluid extraction  41  is preferably configured as a relatively narrow slit. The fluid extraction  41  preferably includes at least one delimitation of the fluid extraction  41  in a plane of the surface of the cleaning area  37 , preferably orthogonal to the z direction, with a centroid. More preferably, the delimitation of the fluid extraction  41  includes at least one ninth delimiting point, which is arranged with the centroid of the delimitation of the fluid extraction  41  in alignment with respect to the cleaning direction G. Preferably, the delimitation of the fluid extraction  41  includes at least one tenth delimiting point, which is arranged with the centroid in alignment with respect to a direction that is orthogonal to the cleaning direction G. Preferably, the delimitation of the fluid extraction  41  includes at least one eleventh delimiting point, which is arranged on the delimitation of the fluid extraction  41 , in an extension of a stretch from the ninth delimiting point to the centroid. Preferably, the delimitation of the fluid extraction  41  includes at least one twelfth delimiting point, which is arranged on the delimitation of the fluid extraction  41 , in an extension of a stretch from the tenth delimiting point to the centroid. The ninth delimiting point and the tenth delimiting point and the eleventh delimiting point and the twelfth delimiting point are each preferably positioned spaced apart from one another by a distance of greater than zero on the delimitation of the fluid extraction  41 . The distance between the ninth delimiting point and the eleventh delimiting point on the delimitation of the fluid extraction  41  is preferably less than the distance between the tenth delimiting point and the twelfth delimiting point on the delimitation of the fluid extraction  41 . A longitudinal direction of the fluid extraction  41  is preferably at least partially orthogonal to a straight line between the ninth delimiting point and the center of gravity of the delimitation of the fluid extraction  41 . Expressed in other words, for example, the at least one fluid extraction  41 , in particular the delimitation of the fluid extraction  41 , preferably has the longitudinal direction of the fluid extraction  41  and a transverse direction of the fluid extraction  41  in the plane spanned by the x direction and the y direction, and/or orthogonal to the z direction. The extension of the fluid extraction  41  is preferably different in its longitudinal direction and in its transverse direction. The fluid extraction  41 , in particular the delimitation of the fluid extraction  41 , preferably has a maximum extension in its longitudinal direction. Preferably, the extension of the fluid extraction  41 , in particular the delimitation of the fluid extraction  41 , is less in the transverse direction of the fluid extraction  41  than in its longitudinal direction. This preferably enables optimal extraction from the at least one positioning gap  07 . 
     The minimum distance between the ninth delimiting point and the eleventh delimiting point of the fluid extraction  41  is preferably less than the minimum distance between the fifth delimiting point and the seventh delimiting point of the fluid extraction  39 , the distance preferably being no more than half as large, and more preferably no more than one fifth as large. 
     The delimitation of the fluid extraction  41  preferably has at least two delimiting points, which have a largest possible distance of all delimiting points of the delimitation of the fluid extraction  41  with respect to one another. The largest possible distance between two delimiting points of the delimitation of the fluid extraction  41  preferably has a minimum length of preferably at least 35 mm (thirty-five millimeters), in particular of at least 40 mm (forty millimeters), more preferably of at least 45 mm (forty-five millimeters), and/or a maximum length of preferably no more than 60 mm (sixty millimeters), in particular of no more than 55 mm (fifty-five millimeters), more preferably of no more than 50 mm (fifty millimeters). More preferably, the largest possible distance between two delimiting points of the delimitation of the fluid extraction  41  has a minimum length that is greater than at least one delimitation of a relevant exit surface  09  of a relevant print head  08 , which in particular is to be cleaned, in a direction that is oriented parallel to the minimum length of the fluid extraction  41 . More preferably, the largest possible distance between two delimiting points of the delimitation of the fluid extraction  41  has a minimum length that is greater than at least one delimitation of a relevant exit surface  09  of a relevant print head  08 , which is in particular to be cleaned, in the x direction. This preferably allows the relevant exit surface  09  to be cleaned, and, additionally or alternatively, at least one bearing surface  11  delimiting the respective exit surface  09  to be cleaned. 
     Preferably, a tangent at the ninth delimiting point of the delimitation of the fluid extraction  41  is positioned at least partially orthogonal to the cleaning direction G and orthogonal to the z direction, and, alternatively or additionally, parallel to the corresponding tangent at the first delimiting point of the delimitation of the fluid supply opening  38 . In addition or as an alternative, the fluid extraction  41  is preferably at least partially positioned orthogonal to the cleaning direction G and orthogonal to the z direction and parallel to the positioning gap  07 . The tangent at the ninth delimiting point of the delimitation of the fluid extraction  41  is preferably oriented parallel to the at least one positioning gap  07  of the assigned nozzle bar  04 , in particular in a plane of the surface of the cleaning area  37 . The tangent at the ninth delimiting point of the delimitation of the fluid extraction  41 , which is arranged at least partially orthogonal to the cleaning direction G and orthogonal to the z direction, preferably has a plane angle of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. 
     The tangent at the ninth delimiting point of the delimitation of the fluid extraction  41  is preferably parallel to a longitudinal direction of the fluid extraction  41 . More preferably, the longitudinal direction of the fluid extraction  41  is oriented parallel to the at least one positioning gap  07  of the assigned nozzle bar  04 . The longitudinal direction of the fluid extraction  41  preferably has a preferably plane angle, in particular an extraction angle  49 , of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation, this meaning counterclockwise. In other words, this means, for example, that the longitudinal direction of the at least one fluid extraction  41  has an identical oblique position with respect to the longitudinal direction of the at least one positioning gap  07 , preferably by the extraction angle  49  with respect to the cleaning direction G. In particular, the extraction angle  49  thus preferably corresponds to the at least partially diagonal overlap in the x direction of the at least two print heads  08  that are arranged next to one another, in particular adjacent to one another. From this, it is apparent, for example, that the extraction angle  49  is preferably acute or obtuse. This acute or obtuse configuration of the extraction angle  49  preferably matches the at least partially diagonal overlap in the x direction of the at least two print heads  08  that are arranged next to one another and/or the orientation of the longitudinal direction of the at least one positioning gap  07 . 
     In a preferred embodiment, the tangent at the first delimiting point of the delimitation of the fluid supply opening  38  and/or the tangent at the fifth delimiting point of the delimitation of the fluid discharge  39  and/or the tangent at the ninth delimiting point of the delimitation of the fluid extraction  41  preferably in each case has a plane angle of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation. More preferably, the longitudinal direction of the fluid supply opening  38  and/or the longitudinal direction of the fluid discharge  39  and/or the longitudinal direction of the fluid extraction  41  in each case has a plane angle of at least 50°, preferably of at least 60°, and of no more than 130°, preferably of no more than 120°, with respect to the cleaning direction G in a positive mathematical direction of rotation. The longitudinal direction of the at least one fluid supply opening  38  and/or the longitudinal direction of the at least one fluid discharge  39  and/or the longitudinal direction of the at least one fluid extraction  41  are preferably oriented parallel to the at least one longitudinal direction of the at least one positioning gap  07  between at least two print heads  08  of the at least one nozzle bar  04  which are arranged next to one another. 
     In a preferred embodiment, the relevant cleaning element  31  comprises at least one cleaning area  37 , by which preferably in each case at least one print head  08  of at least one nozzle bar  04  is to be cleaned and/or can be cleaned. In an alternative exemplary embodiment, the relevant cleaning element  31  preferably comprises at least two cleaning areas  37 . Preferably, the relevant at least two cleaning areas  37  can be connected and/or are connected by at least one connecting element  42 . In this way, preferably at least two print heads  08  are to be cleaned and/or can be cleaned by means of the one relevant cleaning head  31 , which comprises at least two connectable and/or connected cleaning areas  37 , wherein the at least two print heads  08  are preferably arranged in at least two different rows of print heads  08  in the y direction. For example, a cleaning head  31 , in addition or as an alternative to the at least one cleaning area  37 , comprises at least one wiper  52 , which, for example, is arranged in direct contact with at least one exit surface  09  of a print head  08  to be cleaned. 
     In a preferred embodiment, the at least one printing unit  01  of the printing press comprises at least one nozzle bar  04  comprising at least two print heads  08  arranged next to one another, which delimit the at least one positioning gap  07 , comprising at least one feed device  13  assigned to the respective positioning gap  07  and/or at least one cleaning device  18  assigned to the relevant print head  08  of the nozzle bar  04 . 
     For example, the at least one feed device  13  is used in an operating mode of the printing press in which at least one printing fluid can be printed and/or is printed onto at least one printing substrate  03 . As a result of the ejection of at least one fluid, for example a gas and/or a gas mixture, in particular air, and/or a liquid, through the outlet opening  17  of the respective feed device  13 , the penetration and/or accumulation of printing fluid, for example, in the respective positioning gap  07  is preferably made more difficult and/or suppressed. 
     The at least one cleaning device  18 , preferably the at least one cleaning area  37  of the at least one cleaning device  18 , is configured to clean the at least one print head  08 , more preferably the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07 , in a contactless manner. The at least one cleaning device  18  preferably cleans the at least one print head  08  of the print heads  08  in a contactless manner. The at least one print head  08 , preferably the at least one exit surface  09  of the at least one print head  08 , of the at least one nozzle bar  04 , is cleaned in a contactless manner by at least one cleaning device  18  comprising the at least one cleaning element  31  including the at least one fluid supply opening  38 . The at least one cleaning area  37  of the at least one cleaning element  31  is preferably configured to clean the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07  in a contactless manner. This means that only indirect contact, for example by way of a cleaning fluid, is present between the at least one cleaning area  37  and at least one of the components of the at least one print head  08  described below, preferably the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07 . Preferably, the at least one cleaning area  37 , preferably at least the at least one fluid supply opening  38 , is spaced apart from the at least one print head  08 , preferably at least from the at least one exit surface  09  and/or from the at least one bearing surface  11  and/or from the at least one positioning gap  07 , preferably permanently, at a distance of greater than zero. 
     Preferably, the at least one cleaning area  37 , preferably at least the at least one fluid supply opening  38 , is arranged preferably permanently in a contactless manner with respect to the at least one print head  08 , preferably at least with respect to the at least one exit surface  09  and/or with respect to the at least one bearing surface  11  and/or with respect to the at least one positioning gap  07 . 
     In at least one cleaning process, preferably at least the at least one cleaning element  31  and/or the at least one cleaning unit  26  are preferably moved in the cleaning direction G. For example, the relevant cleaning element  31  and/or the relevant cleaning unit  26  have a constant velocity along the cleaning direction G. The fluid supply opening  38  preferably ejects cleaning agent that makes contact with the at least one exit surface  09  and/or the at least one contact surface  11  and/or the at least one positioning gap  07  of the relevant nozzle bar  04 . The cleaning agent preferably cleans the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07 . The fluid discharge  39 , for example, extracts the cleaning agent and/or dirt, for example following the cleaning of the exit surface  09  and/or of the bearing surface  11  and/or of the positioning gap  07  in a preferably first discharge step, preferably by applying negative pressure. In a second discharge step, the fluid extraction  41 , for example, preferably extracts the cleaning agent and/or dirt that remained as residue and/or adhesions on the exit surface  09  and/or on the bearing surface  11  and/or in the positioning gap  07 , for example after the first discharge step. 
     As an alternative or in addition, the cleaning element  31  and/or the cleaning unit  26 , preferably at at least one position that, for example, is assigned to a positioning gap  07 , are slowed down and/or stopped in terms of their velocity in the cleaning direction G, whereby, for example, a cleaning of the relevant positioning gap  07  can be carried out and/or is possible to be carried out. During the at least one cleaning process, the at least one feed device  13  preferably ejects a fluid, for example a gas and/or a gas mixture, in particular air, and/or a liquid, through the at least one outlet opening  17 . In this way, a penetration and/or accumulation of the cleaning agent in the respective positioning gap  07  is made more difficult and/or suppressed during the cleaning process. 
     For example, intensive cleaning of the at least one relevant positioning gap  07  is preferably carried out, wherein the cleaning element  31  and/or the cleaning unit  26 , preferably at the at least one position that is preferably assigned to the respective positioning gap  07 , are slowed down and/or stopped in terms of their velocity in the cleaning direction G, and/or the feed device  13  ejects at least one fluid, for example a gas and/or a gas mixture, in particular air, and/or a liquid. 
     In a preferred embodiment of the cleaning element  31 , the at least one cleaning element  31  includes at least two sliding surfaces  32 , which are arranged behind one another in the cleaning direction G, preferably in alignment with one another. For example, the at least two sliding surfaces  32  are spaced apart from one another at a distance of greater than zero. In particular, at least one edge  51  is arranged in the cleaning direction G downstream from the at least one cleaning area  37 , in particular downstream from the at least one fluid extraction  41 , and/or upstream from the at least one second ramp  34 . The at least one cleaning area  37  is preferably raised in the z direction in relation to a surface of the cleaning element  31  downstream from the at least one edge  51 , in particular in the z direction in relation to the at least one second ramp  34 . In this way, the distance between the cleaning element  31  and the at least one exit surface  09  of the at least one print head  08  is increased, preferably directly downstream from the cleaning area  37 , in particular downstream from the at least one fluid extraction  41 . In particular, the at least one edge  51  prevents smearing of printing fluid, which at this time, preferably when the at least one cleaning element  31  is passing the relevant exit surface  09 , is located at the at least one exit surface  09 . Preferably, at least one of the at least two sliding surfaces  32  that are arranged behind one another in the cleaning direction G is arranged downstream from the at least one cleaning area  37  in the cleaning direction G, in particular at the at least one second ramp  34 . This ensures optimal guidance of the cleaning element  31  in the area downstream from the at least one cleaning area  37 , so that a distance of greater than zero is ensured from the at least one surface of the cleaning element  31  and/or the at least one second ramp  34 , in particular in the z direction, to the at least one exit surface  09 . When the at least one cleaning element  31  is set against the at least one print head  08 , or vice versa, and/or when the cleaning element  31  is moved in or counter to the cleaning direction G, the at least one sliding surface  32  is, preferably all sliding surfaces  32  are, preferably arranged orthogonally to the cleaning direction G upstream or downstream from the at least one exit surface  09 , for example arranged spaced apart from the at least one exit surface  09  orthogonal to the cleaning direction G, that is, preferably arranged laterally. The at least one sliding surface  32  preferably has a larger extension in the cleaning direction G than orthogonal to the cleaning direction G. 
     In a preferred embodiment of the at least one cleaning element  31 , the cleaning element  31  includes at least two cleaning areas  37 , preferably four cleaning areas  37 . The at least one cleaning element  31  preferably has exactly as many cleaning areas  37  as the nozzle bar  04  assigned to this cleaning element  31  has rows of print heads that are arranged next to one another, in particular in the x direction. The at least two cleaning areas  37  are preferably arranged next to one another, orthogonal to the cleaning direction G and/or orthogonal to the y direction and/or in the x direction. Preferably, in this way, at least two rows of print heads  08 , preferably four rows of print heads  08 , more preferably all rows of print heads  08  of a nozzle bar  04 , are cleaned and/or can be cleaned simultaneously and/or with the at least one cleaning element  31 . 
     For example, the at least one cleaning element  31 , preferably when it includes at least two cleaning areas  37 , in each case includes at least one sliding surface  32 , in the x direction upstream from a first cleaning area  37  and/or in the x direction downstream from a last cleaning area  37 . The at least one cleaning element  31  preferably does not include an additional sliding surface  32  between its first and last cleaning areas  37 . For example, in addition or as an alternative, the at least one cleaning element  31 , preferably when it includes at least two cleaning areas  37 , in each case includes at least one guide surface  36 , in the x direction upstream from a first cleaning area  37  and/or in the x direction downstream from a last cleaning area  37 . The at least one cleaning element  31  preferably does not include an additional guide surface  36  between its first and last cleaning areas  37 . 
     In a preferred embodiment, the at least one nozzle bar  04  comprises at least two rows of print heads  08 . The at least two rows of print heads  08  are each arranged with respect to one another at an angle of at least 1° (one degree), preferably of at least 3° (three degrees), more preferably of 4° (four degrees). This is in particular the case when a curved and/or cylindrical printing substrate guide element  02  is situated opposite the at least one nozzle bar  04 . Preferably, the at least two rows of print heads  08  are each arranged with respect to one another at an angle of at least 1° (one degree), preferably of at least 3° (three degrees), more preferably of 4° (four degrees), in relation to a normal vector of the respective exit surfaces  09 . 
     A surface of the cleaning element  31 , which comprises the at least one fluid input  38  and the at least one fluid discharge  39  and the at least one fluid extraction  41 , preferably the plane of the surface of the respective cleaning area  37 , is in each case preferably arranged parallel to the at least one exit surface  09  of the at least one print head  08  that is assigned to this surface and/or this cleaning area  37 . More preferably, this surface and/or this cleaning area  37  is directed at this at least one exit surface  09 . The normal vectors of at least two surfaces of the cleaning element  31 , which each comprise at least one fluid input  38  and at least one fluid discharge  39  and at least one fluid extraction  41 , preferably the surfaces of the at least two cleaning areas  37  of the cleaning element  31 , preferably have an angle of at least 1° (one degree), preferably of at least 3° (three degrees), more preferably of 4° (four degrees), with respect to one another. 
     Preferably, at least one regulator is arranged in the fluid input  38 , in particular in a channel of the fluid input  38 . The at least one regulator is preferably configured to regulate the supply of cleaning agent to the at least one fluid supply opening  38 , in particular as a function of the angular position and/or oblique position of the respective cleaning area  37 . 
     For example, in addition or as an alternative, the at least two cleaning areas  37  of a cleaning element  31  are arranged offset from one another in the cleaning direction G. Preferably, they thereby represent an offset of the present rows of the print heads  08  with respect to one another. 
     The at least one cleaning element  31  preferably additionally comprises the at least one wiper  52  in the cleaning direction G downstream from the at least one cleaning area  37 . The at least one wiper  52  is preferably configured as a wiping lip, for example made of rubber. The at least one wiper  52  preferably extends in the x direction across the entire length of the exit surface  09  of the at least one assigned print head  08  in this direction. 
     The at least one nozzle bar  04  is preferably at least temporarily arranged in the depot position, this being the third service position. 
     The at least one printing unit  01  preferably comprises the at least one sealing element  56 . The at least one sealing element  56  is preferably configured as a rubber lip. The at least one nozzle bar  04  preferably comprises the at least two print heads  08 , more preferably at least four print heads  08 , more preferably at least eight print heads  08 , each including at least one exit surface  09 . The at least two print heads  08 , preferably the at least four print heads  08 , more preferably the at least eight print heads  08 , are preferably arranged in at least one row of print heads  08  along the longest side of the at least one nozzle bar  04 , preferably in the y direction and/or transverse direction A. The at least one sealing element  56  is preferably arranged so as to be at least temporarily in direct contact with the at least two print heads  08 , preferably the at least four print heads  08 , more preferably the at least eight print heads  08 , and/or at least temporarily makes direct contact. The at least one sealing element  56  is preferably arranged so as to be at least temporarily in direct contact with all print heads  08  of the at least one row along the longest side of the at least one nozzle bar  04 , preferably in the y direction and/or transverse direction A. 
     The at least one sealing element  56  is preferably functionally connected to the at least one print head  08 , in particular its exit surface  09 , preferably the at least two print heads  08 , more preferably the at least four print heads  08 , when the at least one nozzle bar  04  is arranged in its depot position, and the at least one cleaning device  18  is arranged its usage position, and, preferably additionally, the at least one cleaning element  31  is arranged in its supply position. 
     The at least one sealing element  56  is preferably attached to at least one supporting surface  57  and/or is fixedly connected thereto. The at least one supporting surface  57  and/or the at least one sealing element  56  preferably each have a longitudinal direction, which is oriented along their longest extension. The longitudinal direction of the at least one sealing element  56  and/or the longitudinal direction of the at least one supporting surface  57  are preferably oriented parallel to the longest side of the at least one nozzle bar  04 , in particular parallel to the transverse direction A and/or parallel to the y direction. The length of the at least one sealing element  56  along its longitudinal direction and/or the length of the at least one supporting surface  57  are preferably greater than the length of the at least one exit surface  09 , more preferably of the at least two exit surfaces  09 , more preferably of the at least four exit surfaces  09 , more preferably of all exit surfaces  09  of the print heads  08  of the at least one nozzle bar  04  that are arranged next to one another. 
     The at least one printing unit  01  preferably comprises at least two sealing elements  56 . Preferably, one of the at least two sealing elements  56  is in each case arranged in the x direction upstream from the at least one exit surface  09 . Preferably, one of the at least two sealing elements  56  is in each case arranged in the x direction downstream from the at least one exit surface  09 . Preferably, a sealing element  56  is in each case at least temporarily in direct contact with, that is, preferably directly touching, the at least one bearing surface  11  of the at least one print head  08  of the at least two print heads  08 , preferably with all bearing surfaces  11  of the print heads  08  arranged next to one another, the bearing surfaces being arranged next to one another in the y direction and/or transverse direction A. The at least one exit surface  09 , preferably the at least two exit surfaces  09 , preferably all exit surfaces  09  of the print heads  08  arranged next to one another are thus preferably delimited and/or enclosed by at least one respective sealing element  56 , at least in and counter to the x direction. Preferably, the two sealing elements  56  are in each case arranged opposite one another and spaced apart from one another at the at least one supporting surface  57  in the x direction. For example, the at least two sealing elements  56  situated opposite one another each comprise two connecting pieces. Preferably, a respective connecting piece is arranged in the y direction at the front end of the nozzle bar  04 , and a respective connecting piece is arranged in the y direction at the rear end of the nozzle bar  04 , so as to connect the two opposing sealing elements  56 . 
     Preferably, the at least two sealing elements  56  and the at least two print heads  08 , preferably the at least four print heads  08 , preferably all print heads  08  of a nozzle bar  04  that are arranged next to one another, form a preferably at least partially self-contained spatial area when they are functionally connected to one another. More preferably, the at least two sealing elements  56  and the two connecting pieces and the at least two print heads  08 , preferably the at least four print heads  08 , preferably all print heads  08  of a nozzle bar  04  that are arranged next to one another, form a preferably at least partially closed spatial area when they are functionally connected to one another. The at least partially self-contained spatial area is preferably configured as a conservation area. The at least two sealing elements  56  preferably delimit the at least one conservation area with the at least two print heads  08 , more preferably additionally with the two connecting pieces. More preferably, the at least two sealing elements  56  and the at least two print heads  08  and the at least one supporting surface  57  form the at least one conservation area. Preferably, the nozzle bar  04  includes exactly one conservation area per row of print heads  08  that are arranged next to one another in the y direction and/or transverse direction A. More preferably, the exactly one conservation area, per row of print heads  08 , encompasses all exit surfaces  09  of all print heads  08  of this row. The conservation area preferably has an atmosphere that includes at least one conservation medium. The at least one conservation medium preferably comprises at least air enriched with water and/or air enriched with printing fluid. For example, the conservation area is rinsed and/or flooded with at least one fluid, for example with air and/or with air enriched, for example, with water, and/or with cleaning agent and/or with printing fluid. This atmosphere is preferably configured to protect the at least one exit surface  09 , and prevents the printing fluid of the at least two print heads  08  from drying out. Preferably, the at least one conservation area is thus configured to at least temporarily seal the at least one exit surface  09  of the at least two print heads  08 , preferably the at least two exit surfaces  09  that are preferably arranged next to one another in the y direction, more preferably the at least four exit surfaces  09  that are preferably arranged next to one another in the y direction, in each case with respect to their surrounding area, and/or the at least one conservation area is preferably configured to conserve printing fluid of the at least two print heads  08 , preferably of the at least four print heads  08 . The at least one sealing element  56  is preferably configured to seal and/or seals at least two exit surfaces  09  of at least two print heads  08  of at least one row of print heads  08  of the at least one nozzle bar  04 . 
     The at least one sealing element  56  is preferably arranged in the at least one crossbar  22 . The at least two print heads  08 , preferably the at least four print heads  08 , are preferably arranged in or at the at least one crossbar  22  during the direct contact with the at least one sealing element  56 . As a result, the depot position is preferably established by the position of the at least one crossbar  22 . For conservation, the at least one sealing element  56 , preferably the at least two sealing elements  56  that are preferably situated opposite one another, are preferably brought in contact with the at least two print heads  08 , preferably the at least four print heads  08 . Preferably, the at least one sealing element  56  is, preferably the at least two sealing elements  56  that are preferably situated opposite one another are, configured to be displaced and/or displaceable relative to the at least two print heads  08  into or out of the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . Preferably, the at least one sealing element  56  is, preferably the at least two sealing elements  56  that are preferably situated opposite one another are, configured to be displaced and/or displaceable relative to the at least two print heads  08  in a direction orthogonal to the longest side of the at least one nozzle bar  04 , preferably orthogonal to the y direction, and/or parallel to the at least one transport path of the at least one printing substrate  03 . The at least one crossbar  22  preferably comprises at least four sealing elements  56 , which are configured to delimit at least two different conservation areas. Preferably, two sealing elements  56  are in each case situated opposite one another in the crossbar  22 , the at least four sealing elements  56  in the crossbar  22  thereby being configured to delimit at least two different conservation areas. Preferably in addition or as an alternative, at least two crossbars  22 , preferably each including at least four sealing elements  56  are configured to be displaced and/or be displaceable jointly. In this way, at least one sealing element  56  is, preferably two sealing elements  56  are, preferably assigned to each row of print heads  08 , for example two rows of print heads  08  of the at least one nozzle bar  04 , for example four nozzle bars  04 , of the printing unit  01 . 
     In a preferred embodiment, the at least one cleaning device  18  comprises the at least one sealing element  56 , preferably the at least two sealing elements  56 . The at least one cleaning device  18  preferably in each case comprises two sealing elements  56  per row of print heads  08  that are arranged next to one another in the y direction, for example at least two rows, preferably exactly two rows. Preferably, the cleaning device  18  comprises the at least one supporting surface  57 , preferably the at least two supporting surfaces  57 , more preferably at least one respective supporting surface  57  for two sealing elements  56  situated opposite one another. More preferably, the at least one supporting surface  57  and/or the at least one sealing element  56  are arranged in the at least one crossbar  22  configured as a collecting trough  22 . The at least one collecting trough  22  preferably at least partially encloses the at least one supporting surface  57 . The at least one cleaning device  18  preferably comprises the at least one cleaning element  31 . The at least one cleaning element  31  is preferably arranged in the supply position when the at least one sealing element  56  is arranged in the direct contact with the at least one print head  08 . The at least one cleaning element  31  is preferably arranged in the supply position when the at least one sealing element  56  is arranged in the at least temporary direct contact with the at least one print head  08 . 
     The at least one crossbar  22 , which is in particular configured as a collecting trough  22 , is preferably configured to collect fluid, for example printing fluid, and/or dirt. In particular, the at least one collecting trough  22  is configured to collect printing fluid, which is ejected by the at least one print head  08  in the depot position. Preferably, the at least one collecting trough is connected to a repository of fluid, for example for recycling or reuse, and/or to a drain, to which the collected fluid and/or dirt are conducted. 
     The at least one cleaning device  18  is preferably at least temporarily arranged in the usage position. The at least one nozzle bar  04  is then preferably selectively arranged at least in the cleaning position or in the depot position. The at least one cleaning device  18  is preferably configured to at least partially clean the nozzle bar  04  arranged in the cleaning position. The at least one sealing element  56  is, preferably the at least two sealing elements  56  are, preferably arranged so as to be in direct contact with the at least one print head  08 , preferably the at least two print heads  08 , more preferably the at least four print heads  08 , of the nozzle bar  04  arranged in the depot position. The at least one nozzle bar  04  is preferably arranged in the idle position or the first service position, before being arranged in the depot position. The at least one nozzle bar  04  is preferably lowered onto the at least one sealing element  56 , preferably onto the at least two sealing elements  56 , for conservation purposes. In particular, while the at least one nozzle bar  04  is being lowered into the depot position, the at least one sealing element  56 , preferably the at least two sealing elements  56 , and/or the at least one crossbar  22  are preferably situated in a position that corresponds to the usage position of the at least one cleaning device  18 . When the at least one cleaning device  18  is preferably arranged in the usage position, the at least one nozzle bar  04  is preferably selectively arranged at least in the first service position, preferably the cleaning position, or in the third service position, preferably the depot position. Preferably, the at least one cleaning device  18  is configured to at least partially clean the nozzle bar  04  that is arranged in the first service position, this being the cleaning position. Preferably, the at least one sealing element  56  is arranged so as to be in direct contact with the at least one print head  08  of the nozzle bar  04  that is arranged in the third service position, this being the depot position. The at least one cleaning device  18  is preferably being arranged and/or is arranged in the usage position. Preferably, the at least one nozzle bar  04  is selectively being arranged and/or is arranged at least in the first service position or in the third service position. Preferably, the at least one cleaning device  18  at least partially cleans the nozzle bar  04  that is arranged in the first service position, or the at least one sealing element  56  preferably makes direct contact with the at least one print head  08  of the nozzle bar  04  that is arranged in the third service position. 
     The at least one printing unit  01  preferably comprises at least one cleaning system  61 . The at least one cleaning system  61  is preferably assigned to at least one nozzle bar  04  of the printing unit  01 . For example, the cleaning system  61  is assigned to at least two, preferably all, nozzle bars  04  of the printing unit  01 . 
     The at least one cleaning system  61  preferably comprises the at least one removal unit  63  including the at least one contact element  64 . The at least one cleaning system  61  preferably comprises the at least one removal unit  63 . More preferably, the cleaning system  61  comprises at least two, preferably at least four, removal units  63 . More preferably, the cleaning system  61  comprises at least as many removal units  63  as the printing unit  01  comprises nozzle bars  04 . More preferably, at least one removal unit  63  is in each case assigned to each row of print heads  08  of the at least one nozzle bar  04 , in particular of all nozzle bars  04  of the printing unit  01 , and/or each row at least temporarily makes contact with at least one removal unit  63 . 
     The at least one cleaning system  61  preferably comprises the at least one carrier  76 . Preferably, the at least one removal unit  63  is arranged on the at least one carrier  76  and/or connected to the at least one carrier  76 . Preferably, at least two removal units  63  are arranged on the at least one carrier  76 , in particular on at least one shared carrier  76 , and/or are connected thereto. Preferably, exactly as many removal units  63  are arranged on the at least one, in particular shared, carrier  76  as the at least one printing unit  01  comprises nozzle bars  04 . Preferably, at least one removal unit  63  that is arranged on the at least one carrier  76  is assigned to each nozzle bar  04 , and/or at least temporarily enters into a functional connection therewith. 
     The at least one cleaning system  61  preferably comprises the at least one guide element  62  and the at least one removal unit  63 . The cleaning system  61  preferably comprises at least two removal units  63 , preferably at least four removal units  63 , more preferably as many removal units  63  as nozzle bars  04  are present in the relevant printing unit  01 . Preferably, the at least one removal unit  63  is configured to move in and/or counter to the cleaning direction G, in particular along the at least one guide element  62 . Preferably in addition or as an alternative, the at least one guide element  62  is preferably configured to move the at least one removal unit  63  in and/or counter to the cleaning direction G. 
     The at least one removal unit  63  preferably comprises the at least one contact element  64 . More preferably, the at least one removal unit  63  comprises exactly one contact element  64 . The at least one contact element  64  is preferably at least temporarily in direct contact with the at least one print head  08 , in at least one contact zone. More preferably, the at least one contact element  64  is preferably at least temporarily in direct contact with the at least one print head  08  of the at least one nozzle bar  04  that is arranged in the second service position. Preferably, the at least one removal unit  63 , in particular the at least one contact element  64 , includes the at least one contact zone with the at least one print head  08 , in which the at least one contact element  64  and the at least one print head  08  are at least temporarily in direct contact with one another. More preferably, the at least one removal unit  63 , in particular the at least one contact element  64 , has exactly one contact zone with the at least one print head  08 . The at least one exit surface  09  of the at least one print head  08  is preferably at least temporarily arranged within the contact zone of the at least one contact element  64  with the at least one print head  08 . The at least one contact element  64  is preferably configured to clean the at least one print head  08 , more preferably the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07 , under at least temporary direct contact. 
     The cleaning system  61  preferably comprises the at least two removal units  63 . The at least two removal units  63  are preferably arranged jointly on the at least one carrier  76 . The at least two removal units  63  preferably have an angle of inclination with respect to the z direction which corresponds to an inclination with respect to the z direction of the at least one nozzle bar  04  and/or of at least one print head  08  of the nozzle bar  04 . The inclination preferably corresponds to the inclination of the assigned nozzle bar  04  and/or its print head  08 . For example, in the case where the transport path of the printing substrate  03  within the printing unit  01  is curved, and the at least two nozzle bars  04  thus preferably have an inclination with respect to the z direction, the at least two removal units  63  have an inclination, preferably with respect to the z direction, which corresponds to the inclination of the nozzle bar  04  assigned thereto and/or its at least one print head  08 . For example, in the case of a planar, for example horizontal transport path, the at least two nozzle bars  04  and/or the at least two removal units  63  are preferably aligned and/or positioned in a planar, preferably horizontal, manner. This preferably allows the at least one contact element  64  to be optimally placed against the at least one print head  08  and/or for it to be cleaned. 
     In a preferred embodiment, the at least one contact element  64  is preferably configured as a wiping element  64 , more preferably as a wiping cloth  64 . For example, the at least one contact element  64  is configured as a wiping cloth  64  having a length of at least 50 cm (fifty centimeters), preferably of at least 1 m (one meter), more preferably of at least 1.5 m (one point five meters). More preferably, the at least one contact element  64  has a length that is greater than the extension of the nozzle bar  04  in the transverse direction A. The at least one wiping cloth  64  is preferably lint-free. The cloth quality, in particular the roughness, of the at least one wiping cloth  64  preferably differs in accordance with the degree of soiling to be cleaned. For example, the at least one wiping cloth  64  has a first roughness in the case of little soiling, and a second roughness in the case of high soiling, wherein the second roughness is higher than the first roughness. The at least one wiping cloth  64  is preferably replaceable and/or adaptable and/or is replaced and/or is adapted in accordance with the degree of soiling. 
     Preferably, in particular when the at least one contact element  64  is configured as a wiping element  64 , the at least one cleaning system  61  is configured as a wiping device  61 . Preferably, in particular when the at least one contact element  64  is configured as a wiping element  64 , the at least one removal unit  63  is configured as a wiping unit  63 . 
     The at least one removal unit  63  preferably comprises at least one pressing element  66 , which is preferably configured as at least one pressing roller  66 . The at least one pressing element  66  is preferably configured to at least temporarily press the at least one contact element  64 , which is in particular configured as a wiping cloth  64 , against the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07  of the at least one print head  08 . The at least one pressing element  66  is preferably resiliently mounted. The at least one resiliently mounted pressing element  66  is preferably configured so as to be set and/or settable with respect to its position in the z direction. Preferably in addition or as an alternative, a contact pressure of the at least one pressing element  66  against the at least one print head  08  is preferably configured to be set and/or settable. In particular, a contact pressure of the at least one pressing element  66 , with which the at least one contact element  64  is pressed against the at least one exit surface  09  and/or the at least one bearing surface  11  and/or the at least one positioning gap  07 , is preferably set and/or settable via the resilient mounting, for example the rigidity of the mounting and/or the position of the mounting in the z direction. 
     The at least one removal unit  63  preferably comprises at least one reservoir  67  of the contact element  64 , which is preferably configured as an unwinding device  67 . For example, unused contact element  64 , which is in particular configured as wiping cloth  64 , is collected at the reservoir  67 , which is output, preferably unwound and/or can be unwound, as needed. The at least one contact element  64 , which is arranged and/or collected at the reservoir  67 , is preferably configured as a roll, for example as a supply roll. The at least one reservoir  67  is preferably arranged in at least one housing  74 . For example, clean contact element  64  is thus protected against dirt and/or other external influences. The at least one reservoir  67  preferably comprises at least one element generating a braking force. For example, the at least one element generating a braking force is configured as at least one spring and/or at least one pressure element. For example, the at least one housing  74  is configured as the at least one element generating a braking force. The at least one reservoir  67  is preferably configured to set and/or introduce the tension of the at least one contact element  64 , which is in particular configured as a wiping cloth  64 , along its guide path, preferably by way of the at least one element generating a braking force. The braking force preferably counteracts a transport movement of the at least one contact element  64 . 
     The at least one removal unit  63  preferably comprises at least one storage device  68  of the at least one contact element  64 , which is preferably configured as a winding device  68 . The at least one storage device  68  is preferably driven and/or connected to at least one drive. For example, at the storage device  68 , contact element  64  is collected and/or can be collected, which was preferably previously used and/or can be used for cleaning at least one print head  08  and/or at least one exit surface  09  and/or at least one bearing surface  11  and/or at least one positioning gap  07 . The at least one storage device  68  is preferably configured to wind contact element  64  and/or contact element  64  can be wound in the at least one storage device  68 . The at least one contact element  64 , which is preferably configured as a wiping cloth  64  and which is arranged and/or collected at the storage device  68 , is preferably configured as a roll, for example as a storage roll. 
     The at least one contact element  64  is preferably configured to be guided and/or guidable from the at least one reservoir  67 , by way of the at least one pressing element  66 , to the at least one storage device  68 . Above and below, this stretch is referred to as the guide path of the contact element  64 . 
     The at least one cleaning system  61  preferably comprises the at least one drive. The at least one storage device  68  is preferably driven and/or connected to the at least one drive. The at least one drive is preferably configured to change the at least one contact element  64  with respect to the contact zone with the at least one print head  08 . The at least one contact element  64  is preferably configured to change at least its surface within the at least one contact zone. The at least one contact element  64  preferably changes at least its surface located within the at least one contact zone. The at least one drive is preferably configured to wind the at least one contact element  64  onto the at least one storage device  68  and/or to unwind it from the at least one reservoir  67 . Preferably in addition or as an alternative, the at least one drive is configured to be pneumatic. This advantageously increases the resistance of the at least one removal unit  63  to fluids and/or environmental influences. For example, as an alternative, the at least one drive is configured as an electric motor. 
     The velocity with which the at least one contact element  64  is changed in terms of the contact zone with the at least one print head  08  is preferably adapted and/or adaptable to a movement of the at least one removal unit  63  in the cleaning direction G and/or to the number of print heads  08  to be cleaned in a cleaning step. The at least one contact element  64  is preferably configured to change its surface within the at least one contact zone. For example, the at least one contact element  64  is configured to continuously change its surface within the at least one contact zone. Preferably as an alternative, the at least one contact element  64  is configured to change at least its surface within the at least one contact zone in a clocked and/or incremental manner. For example, the at least one removal unit  63  has a clock pulse period. 
     The at least one removal unit  63  preferably comprises at least one clock generator  78 . The at least one clock generator  78  is preferably the at least one drive or is connected to the at least one drive, for example by way of at least one line  73  configured as a drive line  73 . The at least one clock generator  78  is preferably configured as a linearly guided element, more preferably as at least one piston and/or at least one pneumatic cylinder. The at least one drive is preferably configured to pneumatically drive the at least one clock generator  78  configured as a linearly guided element. 
     The at least one removal unit  63  preferably comprises at least one sensing element  77 . The at least one clock generator  78  is preferably configured to transmit at least one movement to the at least one pick-up element  77 . The at least one pick-up element  77  is preferably configured as a gear wheel and/or as a ratchet wheel. The at least one pick-up element  77  is preferably functionally connected to the at least one contact element  64 , and the at least one pick-up element  77  is preferably configured to drive the at least one contact element  64 . The at least one pick-up element  77  is preferably configured to drive the at least one storage device  68 . The at least one storage device  68  is preferably in particular configured to wind the at least one contact element  64  using its drive. 
     The at least one clock generator  78  is preferably configured to drive the at least one pick-up element  77 . The at least one pick-up element  77  is preferably configured to drive the at least one storage device  68 . The at least one storage device  68  is preferably configured to transmit at least one movement onto the at least one contact element  64 . Preferably, the at least one clock generator  78  is configured to transmit at least one movement, for example by way of at least one pulse, to the at least one pick-up element  77 , which is configured to transmit this at least one movement to the at least one storage device  68 , and thus to the at least one contact element  64 . The at least one clock generator  78  preferably makes contact with the at least one pick-up element  77  in a linear stroke movement, that is, forward and/or backward, and is configured to thereby move this at least one pick-up element  77  by at least a portion of its circumference. The at least one clock generator  78  is preferably configured to cause the at least one pick-up element  77  to move along a first direction of rotation at least twenty times, preferably thirty times, more preferably at least forty times, before the pick-up element has completed a full revolution of 360° (three hundred sixty degrees). For example, every single pulse that causes the at least one pick-up element  77  to move is referred to as individual clock. 
     The at least one removal unit  63  preferably comprises at least one blocking element  79 , for example an anti-reversing lock. The at least one blocking element  79  is preferably permanently in contact with the at least one pick-up element  77 . The at least one blocking element  79  is preferably configured to preferably selectively block the at least one pick-up element  77  in its movement. More preferably, the blocking element  79  is configured to only allow the first direction of rotation of the at least one pick-up element  77 . The at least one blocking element  79  is preferably configured to block a rotation of the at least one pick-up element  77  counter to the first direction of rotation. 
     The at least one pick-up element  77  and/or the at least one clock generator  78  and/or the at least one blocking element  79  are preferably arranged within the at least one housing  74 . 
     For example, the at least one removal unit  63  comprises at least one deflection means  69 . Preferably, the at least one deflection means  69  is preferably arranged along the guide path of the contact element  64  between the at least one reservoir  67  and the at least one pressing element  66 . For example, in particular when the at least one contact element  64  is configured as a wiping cloth  64 , the wiping cloth  64 , proceeding from the at least one reservoir  67 , is deflected and/or deflectable along its guide path about the at least one deflection means  69  with respect to its transport direction T. In this way, preferably direct contact of the contact element  64  with the at least one print head  08  is only ensured in the at least one contact zone, that is, at the at least one pressing element  66 . For example, in addition or as an alternative to the at least one element generating a braking force, the tension of the at least one contact element  64 , which is in particular configured as a wiping cloth  64 , along its guide path can preferably be set and/or is set by the at least one deflection means  69 . 
     The at least one removal unit  63  preferably comprises at least one nozzle  71 . Preferably, the at least one nozzle  71  is preferably arranged along the guide path of the at least one contact element  64  between the at least one reservoir  67  and the at least one pressing element  66 , and more preferably, it is directed at the guide path of the contact element  64  and/or at the at least one contact element  64 . The at least one nozzle  71  is preferably configured to spray fluid onto the at least one contact element  64  along the guide path of the at least one contact element  64  upstream from the at least one contact zone. The at least one deflection means  69  preferably comprises the at least one nozzle  71 . The at least one deflection means  69  preferably comprises at least two nozzles  71 , more preferably a multiplicity of nozzles  71 . The at least one nozzle  71  is preferably arranged at the circumference of the at least one deflection means  69  and is directed at the guide path of the at least one contact element  64 . For example, at least two nozzles  71  are arranged next to one another along the circumference of the at least one deflection means  69 . 
     The at least one nozzle  71  is preferably connected via at least one supply line  72  to a source of cleaning agent. Preferably, the at least one nozzle  71  is configured to spray fluid, preferably cleaning agent, for example unpigmented printing fluid, onto the at least one contact element  64 , preferably along the guide path of the at least one contact element  64  upstream from the at least one pressing element  66  and/or preferably upstream from the at least one contact zone. For example, in particular when the at least one removal unit  63  has an inclination with respect to a horizontal plane, preferably so that the at least one deflection means  69  with its longitudinal axis has an inclination with respect to the horizontal plane, a first part of nozzles  71  of the at least two nozzles  71  can in each case be activated, which is positioned higher than a second part of nozzles  71  of the at least two nozzles  71 . For example, the at least one supply line  72  is then configured to transport cleaning agent at least to the part of nozzles  71  which is positioned higher than the respective at least one further part of nozzles  71 . This advantageously takes advantage of the gravity of the cleaning agent. Preferably, the cleaning agent then preferably distributes independently among all nozzles  71 . 
     The at least one contact element  64  is preferably dry when arranged at the at least one reservoir  67 . The at least one contact element  64  is preferably moistened and/or is converted into a moist or wet state by spraying on the cleaning agent from the at least one nozzle  71 . For example, the cleaning agent is embodied as ink that does not include any pigments. For example, in an alternative embodiment, a wet contact element  64  can be used and/or is used, which is already configured to be moist or wet, for example saturated with cleaning agent, when it is arranged at the at least one reservoir  67 . For example, in a further alternative embodiment, the contact element  64  is dry when making direct contact with the at least one print head  08 . Preferably, cleaning agent is not sprayed onto the contact element  64  by the at least one nozzle  71  in the process. For example, a combination of one of the embodiments of the at least one contact element  64  as described above is possible so that, for example, first a moist or wet contact is generated in a first cleaning step, and a dry contact is generated in a second cleaning step, between the at least one wiping cloth  64  and the at least one print head  08 . 
     The at least one contact element  63  cleans the at least one print head  08 , in particular its exit surface  09  and/or the at least one bearing surface  11 , preferably by direct contact. The at least one removal unit  63  is preferably moved into the at least one operating position for this purpose. The at least one nozzle bar  04  is preferably lowered onto the at least one contact element  64  and is preferably thereby arranged in the second service position. The removal unit  63  preferably has a relative movement with respect to the at least one print head  08 . The at least one removal unit  63  is preferably moved in the cleaning direction G, for example alternatively counter to the cleaning direction G. The at least one contact element  64  preferably consecutively makes contact with the at least two print heads  08  arranged in one row. For example, the at least one contact element  64  wipes the at least one exit surface  09 , preferably the at least two exit surfaces  09 , and/or the at least one bearing surface  11 , preferably the at least two bearing surfaces  11 . During the movement of the at least one removal unit  63  in or counter to the cleaning direction G, the surface of the at least one contact element  64  is preferably changed. The contact element  64  is preferably unwound and/or wound in the process. With each forward movement in or counter to the cleaning direction G, a different area of the contact element  64  thus makes direct contact with the at least one print head  08 . The change of the surface of the at least one contact element  64  is preferably prompted by way of the at least one clock generator  78  and/or by way of the at least one pick-up element  77 . For example, the at least one contact element  64  is only configured to clean the at least one print head  08  during a movement in the cleaning direction G. For example, as an alternative, the at least one contact element  64  is configured to clean the at least one print head  08  during a movement in the cleaning direction G and during a movement counter to the cleaning direction G. 
     The at least one printing unit  01  preferably comprises the at least one cleaning device  18  and the at least one cleaning system  61 . The at least one cleaning device  18  and the at least one cleaning system  61  can preferably be moved independently of one another. 
     Preferably, the at least one print head  08  of the at least one nozzle bar  04 , preferably the at least one print head  08  of the at least one nozzle bar  04  arranged in the at least one service position, is configured to selectively make contact with the at least one cleaning device  18  and/or contact with the at least one cleaning system  61 . Preferably, the at least one cleaning device  18  and/or the at least one cleaning system  61  selectively make contact with the at least one print head  08 . Preferably in addition or as an alternative, the at least one cleaning device  18  and/or the at least one cleaning system  61  are selectively displaced at least temporarily into the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . Preferably in addition or as an alternative, the at least one cleaning device  18  and/or the at least one cleaning system  61  are selectively displaced into the area between the at least one nozzle bar  04  and the transport path of the at least one printing substrate  03 . More preferably, the at least one cleaning device  18  and/or the at least one cleaning system  61  are displaced independently of one another into the area between the at least one nozzle bar  04  and the transport path of the printing substrate  03 . Preferably in addition or as an alternative, the at least one cleaning device  18  and/or the at least one cleaning system  61  are selectively arranged in the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . 
     Preferably, in a first arrangement of the selective arrangement, the at least one cleaning device  18 , preferably the at least one cleaning element  31 , is arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . The at least one cleaning system  61 , preferably at least the at least one removal unit  63 , is then preferably arranged outside the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . The at least one nozzle bar  04  is preferably arranged in the at least one service position, preferably in the first service position or, for example, in the third service position. In the first arrangement, the at least one cleaning device  18  is preferably configured to clean the at least one print head  08  or, for example, to seal the at least one print head  08  by means of the at least one sealing element  56 . In the first arrangement, the at least one removal unit  63  is preferably arranged in the at least one supply position. 
     Preferably in addition or as an alternative, preferably in a second arrangement of the selective arrangement, the at least one cleaning system  61 , preferably the at least one removal unit  63 , is arranged within the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . The at least one cleaning device  18 , preferably at least the at least one cleaning element  31 , is then preferably arranged outside the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . The at least one nozzle bar  04  is preferably arranged in the at least one service position, preferably in the second service position. In the second arrangement, the at least one cleaning system  61 , preferably the at least one removal unit  63 , is preferably configured to clean the at least one print head  08 . In the second arrangement, the at least one cleaning device  18  is preferably arranged in the at least one storage position. In the second arrangement, the at least one cleaning element  31  is preferably arranged in the at least one supply position. 
     Preferably in addition or as an alternative, preferably in a third arrangement of the selective arrangement, both the at least one cleaning device  18 , preferably at least the at least one cleaning element  31 , and the at least one cleaning system  61 , preferably at least the at least one removal unit  63 , are arranged outside the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 . In the third arrangement, the at least one cleaning device  18  is preferably arranged in the at least one storage position. In the third arrangement, the at least one cleaning element  31  is preferably arranged in the at least one supply position. In the third arrangement, the at least one removal unit  63  is preferably arranged in the at least one supply position. In the third arrangement, the at least one nozzle bar  04  is preferably arranged in the printing position. 
     More preferably, the at least one nozzle bar  04  is first displaced from the at least one printing position into the at least one idle position. The at least one nozzle bar  04  is then preferably displaced from the at least one idle position into the at least one service position. Preferably, the at least one cleaning device  18  and/or the at least one cleaning system  61  are selectively displaced into the area between the at least one nozzle bar  04  and the transport path when the at least one nozzle bar  04  is arranged in the at least one idle position. Preferably in addition or as an alternative, the at least one nozzle bar  04  is selectively lowered onto the at least one cleaning device  18  or onto the at least one cleaning system  61 . The at least one nozzle bar  04  is preferably arranged in the at least one service position at least as a result of being lowered. 
     Preferably, the at least one cleaning device  18  and/or the at least one cleaning system  61  at least temporarily clean the at least one print head  08 . 
     In a preferred embodiment, the at least one sealing element  56 , preferably the at least two sealing elements  56 , and/or the at least one cleaning device  18  and/or the at least one cleaning system  61  are selectively arranged in contact with the at least one nozzle bar  04 . The at least one print head  08  of the at least one nozzle bar  04  is preferably configured to selectively make contact and/or makes contact with the at least one cleaning device  18  and/or with the at least one cleaning system  61  and/or with the at least one sealing element  56 , preferably the at least two sealing elements  56 . The at least one print head  08  of the at least one nozzle bar  04  arranged in the at least one service position is preferably configured to selectively make contact and/or makes contact with the at least one cleaning device  18  and/or with the at least one cleaning system  61  and/or with the at least one sealing element  56 , preferably the at least two sealing elements  56 . The at least one cleaning device  18  is preferably configured to move and/or be movable along the at least one guide element  53  and/or the at least one removal unit  63  is preferably configured to move and/or be movable along the at least one guide element  62 . The at least one print head  08  is preferably selectively cleaned by the at least one cleaning device  18  and/or is cleaned by the at least one cleaning system  61  and/or is conserved and/or is sealed with respect to the surrounding area of the print head  08  by the at least one sealing element  56 , preferably the at least two sealing elements  56 . Preferably, the at least one cleaning device  18  and/or the at least one cleaning system  61  selectively clean the at least one print head  08 , preferably the at least two print heads  08 , more preferably the at least two print heads  08  of a row, of the at least one nozzle bar  04 , preferably of the at least one nozzle bar  04  of the at least four nozzle bars  04 . 
     Above and below, the term “selectively” preferably describes that at least two operating modes to be distinguished from one another, for example at least three operating modes, are present. The at least two operating modes can be assumed as a function of operating specifications or further conditions, preferably independently of one another. If a first element and/or a second element selectively make contact with a third element, this preferably describes that either the first element or the second element or both elements make contact with the third element as a function of operating specifications or other conditions. For this purpose, the press comprises the first element, and the second element, and the third element. 
     The at least one cleaning device  18  is preferably configured to make the selective contact with the at least one print head  08  and/or makes the contact when the at least one nozzle bar  04  previously had a printing operating mode for at least one hour, preferably for at least two hours, and/or when the at least one nozzle bar  04  previously or thereafter had or will have a non-printing operating mode for at least one hour, preferably for at least two hours. The at least one cleaning device  18  is preferably configured to selectively clean and/or selectively cleans the at least one print head  08  when the at least one nozzle bar  04  previously had a printing operating mode for at least one hour, preferably for at least two hours, and/or when the at least one nozzle bar  04  previously or thereafter had or will have a non-printing operating mode for at least one hour, preferably for at least two hours. The at least one cleaning device  18  is preferably selectively arranged in the area between the at least one nozzle bar  04  and the transport path of printing substrate  03  when the at least one nozzle bar  04  previously had a printing operating mode for at least one hour, preferably for at least two hours, and/or when the at least one nozzle bar  04  previously or thereafter had or will have a non-printing operating mode for at least one hour, preferably for at least two hours. 
     The at least one cleaning system  61  is preferably configured to make the selective contact with and/or makes the contact with and/or preferably cleans the at least one print head  08 , and/or is preferably selectively arranged in the area between the at least one nozzle bar  04  and the transport path of printing substrate  03 , when the at least one nozzle bar  04  previously had a printing operating mode for at least six hours, preferably for at least eight hours, that is, printing fluid was transferred onto at least one printing substrate  03 , and/or when the at least one nozzle bar  04  previously or thereafter had or will have a non-printing operating mode for at least four hours, preferably for at least five hours, more preferably for at least six hours. In addition or as an alternative, when the at least one nozzle bar  04  includes printing fluid that has a viscosity, preferably a dynamic viscosity, of at least 3 mPa*s (three millipascal seconds), preferably at least 4.5 mPa*S (four point five millipascal seconds), and/or that has a viscosity of no more than 6 mPa*s (six millipascal seconds), preferably no more than 5.5 mPa*s (five point five millipascal seconds). The preceding viscosity values preferably refer to the viscosity between 20° C. (twenty degrees Celsius) and 40° C. (forty degrees Celsius), preferably of at least 25° C. (twenty-five degrees Celsius) and/or no more than 35° C. (thirty-five degrees Celsius), and/or were preferably determined according to DIN EN ISO 2884-1:2006-09. In addition or as an alternative, when the at least one nozzle bar  04  includes printing fluid having a pigment content of the printing fluid of at least 1%, preferably of at least 2%, more preferably of at least 3%, more preferably of at least 4%, and/or preferably having a pigment content of the printing fluid of no more than 18%, preferably of no more than 14%, more preferably of no more than 10%, more preferably of no more than 7%. In addition or as an alternative, when the at least one printing substrate  03  is configured as paper and/or cardboard and/or corrugated cardboard and/or paperboard, for example since its processing places a particular burden on the printing press. In addition or as an alternative, when the at least one printing substrate  03  includes a pigment coating of at least 5%, preferably at least 8%, more preferably at least 10% of the total weight of the at least one printing substrate  03  and/or when the at least one printing substrate  03  includes a pigment coating no more than 30%, preferably no more than 25%, more preferably no more than 20% of the total weight of the at least one printing substrate  03 . In addition or as an alternative, when the printing fluid is configured for package printing and/or for printing a packaging material. 
     The at least one sealing element  56 , preferably the at least two sealing elements  56  are preferably configured to selectively make contact, and/or make contact, with the at least one print head  08 , preferably the at least two print heads  08 , more preferably the at least four print heads  08 , when the at least one nozzle bar  04  has a non-printing operating mode for at least thirty minutes, preferably for at least sixty minutes. During the at least thirty minutes of the non-printing operating mode, the at least one sealing element  56  preferably makes the selective contact with the at least one print head  08 , preferably upstream or downstream from the at least one cleaning device  18  and/or upstream or downstream from the at least one cleaning system  61 . 
     For example in addition or as an alternative, the at least one bearing surface  11  is cleaned independently of the at least one exit surface  09 . For example, the at least one bearing surface  11  is cleaned by at least one further, second cleaning head, which differs, for example, from the cleaning element  31  described above and preferably configured as a first cleaning head  31 , in terms of the type of cleaning of the cleaning device  18  to be carried out and/or is configured to exclusively clean the at least one bearing surface  11 . For example, the at least one second cleaning head, in addition or as an alternative to the first cleaning head  31 , is arranged in the at least one cleaning unit  26 . For example, the at least one second cleaning head can be removed from or inserted into the at least one cleaning unit  26 . The at least one second cleaning head is preferably attached by way of a locking mechanism, preferably a plug system, in the at least one cleaning unit  26 . In particular, the first cleaning head  31 , which is thus arranged in the at least one cleaning unit  26 , can be at least temporarily exchanged for and/or replaced by the second cleaning head, or vice versa, for example during intensive cleaning of the at least one bearing surface  11 . 
     Although the disclosure herein has been described in language specific to examples of structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described in the examples. Rather, the specific features and acts are disclosed merely as example forms of implementing the claims.