Patent Publication Number: US-11639066-B2

Title: Printing press with charging device

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is the US national phase, under 35 USC § 371, of PCT/EP2021/065113, filed on Jun. 7, 2021, published as WO 2022/028751 A1 on Feb. 10, 2022, and claiming priority to DE 10 2020 120 882.0, filed Aug. 7, 2020, the disclosures of which are expressly incorporated by reference herein in their entireties. 
     TECHNICAL FIELD 
     Examples herein relate to a printing press including at least one circulatingly movable support element that includes a circulatingly movable contact surface intended for contact with a printing substrate. The printing press further includes at least one first print head configured as an ink jet print head, with at least one ejection opening is arranged so as to be directed at the at least one support element. Additionally, the printing press includes at least one first charging device that includes at least one charging electrode, which is arranged so as to be directed at the contact surface. Further, the at least one first charging device includes at least one counter-electrode, and the movable contact surface is at least partially arranged between the at least one charging electrode and the at least one counter-electrode of the at least one first charging device. 
     BACKGROUND 
     A sheet-fed printing press is known from US 2017/0326890 A1, which comprises a curved conveyor belt for sheet travel, wherein a roller is provided for charging, which is in contact with the conveyor belt or a sheet. 
     A device for printing onto sheets is known from EP 2 371 561 A2, which comprises a charging device arranged beneath a conveyor belt. 
     A sheet-fed printing press is known from US 2005/0212871 A1, which comprises a charging device acting from above only on sheets or, alternatively, a charging device acting from beneath on a conveyor belt. 
     A printing press comprising a circulatingly movable support element and an ink jet print head is known from U.S. Pat. No. 10,343,420 B2, comprising a charging device including a charging electrode and a neutralizing device including a grounded electrode. The charging electrode is arranged so as to be in contact with the substrate or close to the substrate. 
     A device for reducing electrical charging in an ink jet printing press is known from US 2014/0 267 501 A1. 
     A device for treating substrate surfaces by means of corona discharge is known from DE 199 23 655 A1. 
     A device is known from US 2002/0 027 588 A1, which can be used to monitor whether substrate sheets tacked to a conveyor belt as a result of an electrical charge detach properly from this conveyor belt again. 
     An ink jet printing press is known from US 2014/0184712 A1, comprising a charging device that includes two rollers forming a nip. In addition, a discharging device is provided. 
     SUMMARY 
     It is an object herein to provide a printing press comprising a charging device. 
     This object is achieved in some examples of a printing press including at least the first charging device in which a smallest distance between at least one charging electrode of the first charging device and the movable contact surface is greater than a smallest distance between an ejection opening of the at least one first print head and the contact surface. In some examples, the smallest distance between the at least one charging electrode of the first charging device and the contact surface is at least 50 mm. 
     An ink jet printing press comprises at least one circulatingly movable support element, which includes a circulatingly movable contact surface intended for contact with a printing substrate. The printing press comprises at least one first ink jet print head, whose at least one ejection opening is arranged so as to be directed at the at least one support element and, in particular, at the contact surface. The printing press comprises at least one first charging device, in particular for electrostatically charging printing substrate. The at least one first charging device comprises at least one, in particular upper, charging electrode, which is in particular arranged so as to be directed from above at the contact surface. The at least one first charging device comprises at least one, in particular lower, counter-electrode. The contact surface is at least partially arranged between the at least one charging electrode and the at least one counter-electrode of the at least one first charging device. A smallest distance between the at least one charging electrode, and preferably each charging electrode, of the first charging device and the contact surface is greater than a smallest distance between an ejection opening, and preferably each ejection opening, of the at least one first print head and the contact surface. An advantage of such a printing press is in particular that printing substrate, in particular sheets, can be fixed at the contact surface, without coming in contact with the surface of the printing substrate that is to be printed or has already been printed. In this way, it is possible to create a high-quality print image, while at the same time protecting the printing substrate. In particular in the case of multiple print heads, which are arranged spaced apart from one another in succession along a transport path intended for a transport of printing substrate, it can be ensured that register-accurate printing without smearing can be achieved. Moreover, it is possible, at least in the region of the at least one print head, to transport the printing substrate with at least reduced vacuum pressure, or without vacuum pressure, so that a respective trajectory of ink droplets is not negatively influenced by air flows. Additionally, wear of a conveyor belt can be reduced by using vacuum pressure that is at least reduced. 
     The smallest distance between the at least one charging electrode, and preferably each charging electrode, of the first charging device is at least 50 mm. In a refinement, the printing press is preferably characterized in that the smallest distance between the at least one charging electrode, and preferably each charging electrode, of the first charging device and the contact surface is at least 60 mm, more preferably at least 65 mm, and still more preferably at least 70 mm. This successfully ensures a particularly reliable transport of the printing substrate. In addition, a high electric field strength and/or high charging can be generated, and nonetheless an electrical breakdown can be avoided. 
     In an alternative or additional refinement, the printing press is preferably characterized in that at least one first position sensor is provided, by means of which a height of a printing substrate relative to the contact surface can be ascertained. In this way, an automated emergency-off function and/or control of the charge are made possible. In an alternative or additional refinement, the printing press is preferably characterized in that first the at least one first charging device, and thereafter the at least one first print head, are arranged along a transport path intended for a transport of printing substrate. In this way, it is ensured that the printing substrate does not damage the print head since the printing substrate rests against the contact surface. In an alternative or additional refinement, the printing press is preferably characterized in that at least one detection zone of the at least one first position sensor is arranged along the transport path intended for a transport of printing substrate, downstream from the at least one first print head. In this way, control of the charge can take place in a particularly favorable manner since a satisfactory measurement result downstream from the print head allows an at least satisfactory condition to be inferred in the region of the print head. 
     In an alternative or additional refinement, the printing press is preferably characterized in that at least one second charging device is arranged along the transport path intended for a transport of printing substrate, downstream from the at least one first print head and/or downstream from the at least one detection zone of the at least one first position sensor, and at least one second print head is arranged thereafter. 
     In an alternative or additional refinement, the printing press is preferably characterized in that a voltage of at least 25 kV, more preferably at least 30 kV, and still more preferably at least 35 kV, and independently thereof preferably no more than 45 kV, and more preferably no more than 40 kV, is present between the at least one charging electrode and the at least one counter-electrode of the first charging device. 
     In an alternative or additional refinement, the printing press is preferably characterized in that a transport path intended for a transport of printing substrate extends between the at least one circulating contact surface and the at least one charging electrode of the at least one first charging device. In this way, an alignment of the field lines of the electrical field in the area of the boundary between the contact surface and the printing substrate is optimized. 
     In an alternative or additional refinement, the printing press is preferably characterized in that the at least one first charging device is configured as a DC charging device. In this way, particularly efficient and uniform charging is achieved. 
     In an alternative or additional refinement, the printing press is preferably characterized in that at least one first field strength sensor for measuring an electric field strength is arranged in particular along the transport path intended for the transport of printing substrate, downstream from the at least one first charging device and/or downstream from the at least one first print head. 
     In an alternative or additional refinement, the printing press is preferably characterized in that a transport path intended for the transport of printing substrate extends in a substantially flat manner, at least from the charging electrode of the first charging device to the at least one second print head. This also allows thick printing substrates, for example corrugated cardboard sheets, to be transported. 
     In an alternative or additional refinement, the printing press is preferably characterized in that the at least one circulatingly movable support element is configured as a conveyor belt and/or as a suction conveyor belt. In an alternative or additional refinement, the printing press is preferably characterized in that the printing press comprises at least one bracing device, which includes a sliding surface that braces the at least one conveyor belt and, more preferably, is at least partially metallic, and that the at least one bracing device is arranged so as to act as the at least one counter-electrode. 
     In an alternative or additional refinement, the printing press is preferably characterized in that the printing press is configured as a sheet-fed printing press and/or comprises at least one sheet feeder for sheet-format printing substrate, which more preferably comprises a singulating device arranged beneath a piling region intended for a sheet pile, in particular for singulating sheet-format printing substrate from at least one pile of sheets from beneath. 
     In an alternative or additional refinement, the printing press is preferably characterized in that the printing press is configured as a web-fed printing press and/or comprises at least one roll unwinding device for web-format printing substrate. 
     In an alternative or additional refinement, the printing press is preferably characterized in that the at least one circulatingly movable support element is configured as a central cylinder. 
    
    
     
       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 illustration of an area of a printing unit comprising print heads and charging devices; 
         FIG.  2    a schematic illustration of a sheet-fed printing press comprising a conveyor belt as a support element; 
         FIG.  3    a schematic illustration of a printing unit comprising print heads, charging devices and suction boxes; 
         FIG.  4    a schematic illustration of a web-fed printing press comprising a central cylinder as support element; and 
         FIG.  5    a schematic illustration of electrodes of a charging device between which a voltage is present. 
     
    
    
     DETAILED DESCRIPTION 
     A printing press  01  is preferably configured as an ink jet printing press  01 . The printing press  01  is in particular used to print onto printing substrate  02 . The printing press  01  is, for example, configured as a sheet-fed printing press  01 , that is, as a printing press  01  for sheet-format printing substrate  02 . The printing press  01  is, for example, configured as a corrugated cardboard sheet-fed printing press  01 , that is, as a printing press  01  for printing onto sheets  02  made of corrugated cardboard. As an alternative, the printing press  01  is configured as a web-fed printing press  01 . To the extent that, above and below, features are described based on an embodiment as a sheet-fed printing press  01 , these also apply to a general printing press  01 , in particular also for a web-fed printing press  01 , provided this does not result in any contradictions. 
     Preferably, a transport path for a transport of printing substrate  02  through the printing press  01  is provided. The transport path intended for the transport of printing substrate  02  is in particular the spatial area that the printing substrate  02 , if present, regularly takes up and/or would take up, optionally at least temporarily. In the case of a curved transport path, a transport direction T is preferably in each case the direction T that runs tangential to a segment and/or point of the intended transport path closest to a respective reference point and that is provided for the transport of the printing substrate  02  at this segment and/or point. This respective reference point is preferably situated at the point and/or at the component that is being related to the transport direction T. The transport direction T thus preferably in each case extends along the transport path intended for printing substrate  02 . A transverse direction A is preferably a direction A that extends orthogonally to the transport direction T and horizontally. A working width of the printing press  01  is preferably a dimension that preferably extends in the transverse direction A. The working width of the printing press  01  preferably corresponds to a maximum width that a printing substrate  02  is permitted to have for the printing press  01  to still be able to be print it, that is, in particular a maximum sheet width and/or web width and/or width of the printing substrate  02  that the printing press  01  is able to process. The width of a printing substrate  02  shall, in particular, be understood to mean its dimension in the transverse direction A. The working width of the printing press  01  is, for example, at least 20 cm, preferably at least 50 cm, more preferably at least 100 cm, still more preferably at least 150 cm, still more preferably at least 200 cm, and still more preferably at least 250 cm. 
     The printing press  01  comprises at least one circulatingly movable support element  07 , which includes a circulatingly movable contact surface  08  intended for contact with a printing substrate  02 . Depending on the configuration of the printing press  01 , the at least one support element  07  is, for example, configured to be flexible, in particular as a conveyor belt  18 , or rigid, in particular as a cylinder  29 , in particular a central cylinder  29 . The printing press  01  comprises at least one first print head  09 , which is in particular configured as an ink jet print head  09 . The at least one first print head  09  preferably includes at least one ejection opening  12 , which is in particular used to eject ink droplets in a targeted manner. The at least one first print head  09  is preferably configured as a print head  09  operating according to the drop-on-demand principle. Preferably, the at least one ejection opening  12  of the at least one first print head  09  is arranged so as to be directed at the at least one support element  07 , and in particular at the contact surface  08  of this at least one support element  07 . The at least one support element  07  is in particular used to hold the printing substrate  02  in a defined position while the ink is being applied thereto. Preferably, the contact surface  08  is a contact surface  08  that can be moved relative to the at least one first print head  09 . Preferably, the contact surface  08  is a contact surface  08  that is circulatingly movable together with the printing substrate  02 . 
     The printing press  01  preferably comprises at least one charging device  03 ;  13 , in particular for electrostatically charging printing substrate  02 . More preferably, the printing press  01  comprises at least one first charging device  03 , and still more preferably additionally at least one second charging device  13 . The respective at least one charging device  03 ;  13  is in particular used to fix printing substrate  02  relative to the at least one support element  07 . 
     The at least one first charging device  03  comprises at least one charging electrode  04 , which is arranged so as to be directed at the contact surface  08 . Preferably, the at least one first charging electrode  04  is at least partially arranged above the contact surface  08  and/or arranged so as to be directed from above at the contact surface  08 . The at least one first charging device  03  preferably comprises at least one counter-electrode  06 . The at least one counter-electrode  06  is preferably arranged beneath the at least one contact surface  08  and/or at least beneath parts of the at least one support element  07 . Preferably, the transport path intended for a transport of printing substrate  02  extends between the at least one circulatingly movable contact surface  08  and the at least one charging electrode  04  of the at least one first charging device  03 . Preferably, the contact surface  08  is at least partially arranged between the at least one charging electrode  04  and the at least one counter-electrode  06  of the at least one first charging device  03 . 
     Preferably, the at least one first charging device  03  is configured such that at least one side of the printing substrate  02 , and more preferably the entire printing substrate  02 , can be electrostatically charged without contact with the first charging device  03 . In this way, the corresponding surface of the printing substrate  02  can be treated gently, in particular in the case of an interposed charging process. Preferably, a smallest distance a between the at least one charging electrode  04  of the at least one first charging device  03  and the contact surface  08  is greater than a smallest distance b between an ejection opening  12 , and preferably each ejection opening  12 , of the at least one first print head  09  and the contact surface  08 . More preferably, the smallest distance a between the at least one charging electrode  04 , and preferably each charging electrode  04 , of the at least one first charging device  03  and the contact surface  08  is at least 50 mm, still more preferably at least 60 mm, still more preferably at least 65 mm, and still more preferably at least 70 mm. 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one first position sensor  17  is provided, by means of which a height position of a printing substrate  02  relative to the contact surface  08  can be ascertained. The at least one first position sensor  17  is preferably configured as a laser measuring device  17 , in particular for triangulation measurement. 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that first the at least one first charging device  03 , and thereafter the at least one first print head  09 , are arranged along a transport path intended for a transport of printing substrate  02 . In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one detection zone of the at least one first position sensor  17  and/or the at least one first position sensor  17  are arranged along the transport path intended for the transport of printing substrate  02 , downstream from the at least one first print head  09 . 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that the at least one first charging device  03  is configured as a DC charging device  03 . This means in particular that a sign of the voltage present at the particular charging electrode  04  does not change during operation. Preferably, a voltage of at least 25 kV, preferably at least 30 kV, and more preferably at least 35 kV, and independently thereof preferably of no more than 45 kV, and more preferably no more than 40 kV, is present between the at least one charging electrode  04  and the at least one counter-electrode  06  of the first charging device  03 , at least in one operating mode of the printing press  01 . In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one first field strength sensor  27  for measuring an electric field strength is arranged in particular along the transport path intended for the transport of printing substrate  02 , downstream from the at least one first charging device  03  and/or downstream from the at least one first print head  09 . This at least one first field strength sensor  27  is preferably connected by circuitry to the at least one first charging device  03  such that they form a control loop, in particular for controlling the electric field strength and/or the voltage present at the at least one charging electrode  04  and/or a vacuum pressure of the conveyor belt  18  prevailing in the area of the at least one second print head  11 . Preferably, alternatively or additionally, the at least one first position sensor  17  is connected by circuitry to the at least one first charging device  03  such that they are part of a control loop, in particular for controlling the electric field strength and/or the voltage present at the at least one charging electrode  04  and/or a vacuum pressure of the conveyor belt  18  prevailing in the area of the at least one second print head  11 . In this way, optimized charging can take place. As an alternative or in addition, the at least one first position sensor  17  is connected by circuitry to a preferably automated emergency-off function for terminating a transport of printing substrate. In this way, damage to, for example, the at least one first print head  09  can preferably be prevented. 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one second charging device  13  is arranged along the transport path intended for a transport of printing substrate  02 , downstream from the at least one first print head  09  and/or downstream from the at least one detection zone of the at least one first position sensor  17 , and at least one second print head  11  is arranged thereafter. 
     The at least one second charging device  14  comprises at least one charging electrode  14 , which is arranged so as to be directed at the contact surface  08 . Preferably, the at least one second charging electrode  14  is at least partially arranged above the contact surface  08  and/or arranged so as to be directed from above at the contact surface  08 . The at least one second charging device  13  preferably comprises at least one counter-electrode  16 . The at least one counter-electrode  16  is preferably arranged beneath the at least one contact surface  08  and/or at least beneath parts of the at least one support element  07 . Preferably, the transport path intended for a transport of printing substrate  02  extends between the at least one circulatingly movable contact surface  08  and the at least one charging electrode  14  of the at least one second charging device  13 . Preferably, the contact surface  08  is at least partially arranged between the at least one charging electrode  14  and the at least one counter-electrode  16  of the at least one second charging device  13 . 
     Preferably, the at least one second charging device  13  is configured such that at least one side of the printing substrate  02 , and more preferably the entire printing substrate  02 , can be electrostatically charged without contact with the second charging device  13 . In this way, the corresponding surface of the printing substrate  02  can be treated gently, in particular in the case of an interposed charging process. Preferably, a smallest distance a between the at least one charging electrode  14  of the at least one second charging device  13  and the contact surface  08  is greater than a smallest distance b between an ejection opening  12 , and preferably each ejection opening  12 , of the at least one second print head  11  and the contact surface  08 . More preferably, the smallest distance a between the at least one charging electrode  14 , and in particular each charging electrode  14 , of the at least one second charging device  13  and the contact surface  08  is at least 50 mm, more preferably at least 60 mm, still more preferably at least 65 mm, and still more preferably at least 70 mm. 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one second position sensor  34  is provided, by means of which a height position of a printing substrate  02  relative to the contact surface  08  can be ascertained. The at least one second position sensor  34  is preferably configured as a laser measuring device  34 , in particular for triangulation measurement. 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that first the at least one second charging device  13 , and thereafter the at least one second print head  11 , are arranged along a transport path intended for a transport of printing substrate  02 . In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one detection zone of the at least one second position sensor  34  and/or the at least one second position sensor  34  are arranged along the transport path intended for the transport of printing substrate  02 , downstream from the at least one second print head  11 . 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that the at least one second charging device  13  is configured as a DC charging device  13 . This means in particular that a sign of the voltage present at the particular charging electrode  14  does not change during operation. Preferably, a voltage of at least 25 kV, more preferably at least 30 kV, and still more preferably at least 35 kV, and independently thereof preferably of no more than 45 kV, and more preferably no more than 40 kV, is present between the at least one charging electrode  14  and the at least one counter-electrode  16  of the second charging device  13 , at least in one operating mode of the printing press  01 . In an alternative or additional refinement, the printing press  01  is preferably characterized in that at least one second field strength sensor  36  for measuring an electric field strength is arranged in particular along the transport path intended for the transport of printing substrate  02 , downstream from the at least one second charging device  13  and/or downstream from the at least one second print head  11 . This at least one second field strength sensor  36  is preferably connected by circuitry to the at least one second charging device  13  such that they form a control loop, in particular for controlling the electric field strength and/or the voltage present at the at least one charging electrode  14  and/or a vacuum pressure of the conveyor belt  18  prevailing in the area of the at least one second print head  11 . Preferably, alternatively or additionally, the at least one second position sensor  34  is connected by circuitry to the at least one second charging device  13  such that they form a control loop, in particular for controlling the electric field strength and/or the voltage present at the at least one charging electrode  14  and/or a vacuum pressure of the conveyor belt  18  prevailing in the area of the at least one second print head  11 . In this way, optimized charging can take place. As an alternative or in addition, the at least one second position sensor  34  is connected by circuitry to a preferably automated emergency-off function for terminating a transport of printing substrate. In this way, damage to, for example, the at least one second print head  11  can preferably be prevented. 
     In one exemplary embodiment, the at least one circulatingly movable support element  07  is configured as a conveyor belt  18 . Preferably, the transport path intended for the transport of printing substrate  02  extends in a substantially flat manner, and still more preferably in a completely flat manner, at least from the charging electrode  04  of the first charging device  03  to the at least one first print head  09 . A substantially flat section of a transport path intended for printing substrate  02  in this context shall be understood to mean a section that has a minimum radius of curvature of at least 2 meters, more preferably at least 5 meters, and still more preferably at least 10 meters, and still more preferably at least 50 meters. A completely flat section has an infinitely large radius of curvature and is thus likewise substantially flat and therefore likewise has a minimum radius of curvature of at least 2 meters. More preferably, the printing press  01  comprises at least one second charging device  13  along the transport path intended for the transport of printing substrate  02 , downstream from the at least one first print head  09 , and thereafter at least one second print head  11 . Preferably, the transport path intended for the transport of printing substrate  02  extends in a substantially flat manner, and still more preferably in a completely flat manner, at least from the charging electrode  04  of the first charging device  03  to the at least one second print head  11 . 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that the printing press  01  comprises at least one bracing device  26 , which includes a sliding surface  28  that braces the at least one conveyor belt  18  and preferably is metallic, and that the at least one bracing device  26  is arranged so as to act as the at least one counter-electrode  06 . This bracing device  28  extends, for example, at least in the region of the at least one first charging electrode  03  along the transport path intended for the transport of printing substrate  02 . In at least one other region of the transport path intended for the transport of printing substrate  02 , for example, an in particular electrically neutral or grounded bracing device  31  that is separate therefrom is provided. Alternatively, the bracing device  28  acting as the counter-electrode  06  extends along the transport path intended for the transport of printing substrate  02  beyond the region of the at least one charging electrode  03 ;  13 . 
     In an alternative or additional refinement, the printing press  01  is preferably characterized in that the at least one conveyor belt  18  is configured, at least in areas, as a suction conveyor belt  18 . A suction conveyor belt  18  shall be understood to mean a conveyor belt  18  that has openings and is guided via at least one suction box  32 . The at least one suction box  32  is preferably connected to a vacuum source  33 , for example a pump  33 . The vacuum pressure is then passed on through the openings in the suction conveyor belt  18  and is used to hold the printing substrate  02  on the contact surface  08 . Preferably, the conveyor belt  18 , along the transport path intended for the transport of printing substrate  02 , is arranged so as to be exclusively guided by guide elements that are fixed with respect to rotary movements, at least between the first charging device  03  and the at least one first print head  09 , and more preferably the at least one second print head  11 . In particular, no supporting rolls are preferably arranged in this area. 
     For example, no vacuum pressure that acts from beneath on the conveyor belt  18  is provided in at least one idle region around the at least one print head  09  and/or around the at least one second print head  11 , even if the conveyor belt  18  is configured and/or operated in other locations as a suction conveyor belt  18 . Preferably, at least one first such idle region extends, proceeding from the at least one first print head  09 , counter to the transport path intended for the transport of printing substrate  02 , over at least 5 cm, more preferably at least 8 cm, and still more preferably at least 10 cm, and independently thereof, proceeding from the at least one first print head  09 , along the transport path intended for the transport of printing substrate  02 , over at least 5 cm, more preferably at least 8 cm, and still more preferably at least 10 cm. Preferably, at least one second such idle region extends, proceeding from the at least one second print head  11 , counter to the transport path intended for the transport of printing substrate  02 , over at least 5 cm, more preferably at least 8 cm, and still more preferably at least 10 cm, and independently thereof, proceeding from the at least one second print head  11 , along the transport path intended for the transport of printing substrate  02 , over at least 5 cm, more preferably at least 8 cm, and still more preferably at least 10 cm. 
     Preferably, the printing press  01  is configured as a sheet-fed printing press  01  and/or the printing press  01  comprises at least one sheet feeder  19  for sheet-format printing substrate  02 , which more preferably comprises a singulating device  23  that is arranged beneath a piling region  22  intended for a sheet pile  21 , in particular for singulating sheet-format printing substrate  02  from at least one sheet pile  21  from beneath. Such a sheet-fed printing press  01  comprises, for example, a sheet feeder  19 , at least one printing unit  37 , in particular a non-impact printing unit  37 , and at least one delivery  38 . The at least one printing press  37  preferably comprises the at least one first print head  09 , and more preferably also the at least one second print head  11 . Preferably, at least one priming unit  39  is arranged along the transport path intended for the transport of printing substrate  02 , upstream from the at least one printing unit  37 , and is configured, for example, as a flexographic printing unit  39 . Preferably, at least one coating unit  41  is arranged along the transport path intended for the transport of printing substrate  02 , downstream from the at least one printing unit  37 , and is configured, for example, as a flexographic printing unit  41 . (This is also depicted schematically in  FIGS.  2  and  3    by way of example.) 
     The embodiment of the printing press  01  comprising a conveyor belt  18 , however, can also be utilized as a web-fed printing press  01  with appropriate feeding and/or removal of the printing substrate  02 . 
     In another exemplary embodiment, the at least one circulatingly movable support element  07  is configured as a cylinder  29 , in particular as a central cylinder  29 . Preferably, the at least one first print head  09 , and more preferably also the at least one second print head  11 , are then in particular arranged so as to be directed radially at the cylinder  29  or central cylinder  20 . The at least one first charging device  03  then preferably comprises the at least one first charging electrode  04 , which, as viewed in the radial direction, is arranged outside the cylinder  29  or central cylinder  29 . The at least one first charging device  03  then preferably comprises at least one counter-electrode  06 , which is arranged radially within the cylinder  29  or central cylinder  29 . For example, the printing press  01  is then configured as a web-fed printing press  01  and/or the printing press  01  then comprises at least one roll unwinding device  24  for web-format printing substrate  02 , which is configured, for example, as a reel changer  24  for a flying reel change. The printing press  01  preferably comprises a substrate output device  42 , which is configured, for example, as a winding device  42  and/or a cutting device  42  and/or a folding device  42 . Web-format printing substrate  02  can, for example, be transported by means of diverting, actively or passively driven rollers and/or cylinders and/or fixed guide elements and/or conveyor belts and/or suction systems. (This is also depicted schematically in  FIG.  4    by way of example.) 
     The embodiment comprising a cylinder  29  can also preferably be utilized as a sheet-fed printing press  01  with appropriate feeding and/or removal of the printing substrate  02 , and optionally further holding elements. 
     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.