Patent Publication Number: US-2022234360-A1

Title: Modular printing bar for an inkjet printing device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to German Patent Application No. 102021101307.0, filed Jan. 22, 2021, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Field 
     The disclosure relates to a modular print bar for an inkjet printing device, having at least one first print head module and at least one second print head module, wherein each print head module comprises a base plate with which at least one print head can be connected. 
     Related Art 
     Print bars for inkjet printing systems are typically constructed for a predetermined number of print heads, in particular for five, ten, or fifteen print heads. Given a variation of the number and/or the type of the print heads, a new print bar must normally be constructed. 
     From the document U.S. Pat. No. 6,637,858 B2, an inkjet printing unit is known in which a plurality of printing modules can be combined with one another, wherein each printing module comprises a plurality of print heads, so that a certain flexibility is achieved in the design of the print bar. However, how the supplying of the print heads with ink within the printing modules takes place is not known from the cited prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the embodiments of the present disclosure and, together with the description, further serve to explain the principles of the embodiments and to enable a person skilled in the pertinent art to make and use the embodiments. 
         FIG. 1  a schematic plan view of a print bar having two print head modules according to a first embodiment, 
         FIG. 2  a schematic side view of the print bar according to  FIG. 1 , 
         FIG. 3  a schematic plan view of a print bar having two print head modules according to a second embodiment, 
         FIG. 4  a first schematic front view of the print bar according to  FIG. 3 , 
         FIG. 5  a second schematic side view of the print bar according to  FIG. 3 , 
         FIG. 6  a schematic plan view of a print bar having two print head modules according to a third embodiment, 
         FIG. 7  a schematic side view of the print bar according to  FIG. 6 , 
         FIG. 8  a schematic plan view of a print bar having two print head modules according to a fourth embodiment, 
         FIG. 9  a schematic side view of the print bar according to  FIG. 8 , 
         FIG. 10  a schematic plan view of a print bar having two print head modules according to a fifth embodiment, 
         FIG. 11  a bottom schematic view of the print bar according to  FIG. 10 , 
         FIG. 12  a bottom schematic view of a print bar having five print head modules arranged with an offset according to a sixth embodiment, and 
         FIG. 13  a seventh embodiment in which the print bar according to  FIG. 1  is introduced into a rail. 
     
    
    
     The exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. Elements, features and components that are identical, functionally identical and have the same effect are—insofar as is not stated otherwise—respectively provided with the same reference character. 
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it will be apparent to those skilled in the art that the embodiments, including structures, systems, and methods, may be practiced without these specific details. The description and representation herein are the common means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring embodiments of the disclosure. The connections shown in the figures between functional units or other elements can also be implemented as indirect connections, wherein a connection can be wireless or wired. Functional units can be implemented as hardware, software or a combination of hardware and software. 
     It is the object of the disclosure to specify a modular print bar that has an especially compact and flexible design and ensures a simple supplying of the print heads with ink. 
     In an exemplary embodiment, the first print head module and the second print head module respectively comprise at least one first ink supply line running in the base plate to supply ink to the respective print head. The first print head module and the second print head module can be firmly connected to the print bar such that a connection can be established between the first ink supply line of the first print head module and the first ink supply line of the second print head module. An especially compact design of the print bar is thereby achieved. 
     In an exemplary embodiment, the first print head module comprises a first carrier element and the second print head module comprises a second carrier element. The center planes of the carrier elements are respectively arranged at an angle to the center planes of the respective base plate, wherein the angle is preferably 90°. In the first carrier element and in the second carrier element, a first ink supply line respectively runs for supplying ink to the respective print head. The first print head module and the second print head module can be firmly connected to the print bar such that a connection can be established between the first ink supply line of the first print head module and the first ink supply line of the second print head module. An especially simple and stable design of the print bar is thereby achieved. 
     In the achievements known from the prior art, the ink to be supplied to the print jobs is pre-tempered in a heat exchanger and/or with the aid of a heating element so that it exhibits desired properties during the printing process, for example a predetermined viscosity. The temperature of the print heads in the print bar must also be regulated, since dissipation loss in the form of heat is generated and emitted during the processing of the print data. In the achievements known from the prior art, the cooling of the heads and the tempering of the ink take place independently of one another. 
     In one or more exemplary embodiments, coolant supply lines travel closely and/or parallel to the ink supply lines, such that the ink supplied in the ink supply lines can be tempered with the aid of coolant directed in the coolant supply lines. It is thereby achieved that the ink and the print heads are tempered in an especially simple manner. 
       FIG. 1  shows a schematic plan view of a print bar  10  having a first print head module  100  and having a second print head module  200 , according to a first embodiment. The first print head module  100  and the second print head module  200  are firmly connected with one another via a material bond, in particular an adhesive bond. Each print head module  100 ,  200  comprises a base plate  102 ,  202  that is respectively connected with a print head  104 ,  204 . The connection of the base plates  102 ,  202  with the respective print head  104 ,  204  takes place with the aid of a mount (not shown) in which the respective print head  104 ,  204  is accommodated so as to be swappable. 
     An ink supply line  106 ,  206  for supplying ink to the respective print heads  104 ,  204  is respectively integrated into the base plates  102 ,  202 . The ink supply lines  106 ,  206  travel in cutouts of the base plates  102 ,  202 . The cutouts may in particular be produced via bores. The ink supply line  106  travels between a first opening  110  of the base plate  102  and a second opening  112  of the base plate  102 . The ink supply line  206  travels between a first opening  210  of the base plate  202  and a second opening  212  of the base plate  202 . 
     A hose fitting  111  is arranged at the first opening  110  of the base plate  102 , in particular is glued or screwed to the base plate  102 . The ink supply line  106  is connected to an external ink supply line  14  via the hose fitting  111 . The ink supply line  106  supplies ink in the arrow direction  16  from an ink supply unit  12 , via the external ink supply line  14 . Via a connector  108  of the first print head module  100 , ink is conveyed from an ink outlet opening of the ink supply line  106  into a connecting hose  114  that is connected with a connector  116  of the print head  104  accommodated in the first print head module  100 , so that ink is supplied in the arrow direction  18  from the ink supply line  106  to the first print head  104 . 
     The second opening  112  of the base plate  102  of the first print head module  100  adjoins the first opening  210  of the base plate  202  of the second print head module  200 . Via the openings  112 ,  210 , a connection is established between the ink supply line  106  of the first print head module  100  and the ink supply line  206  of the second print head module  200 . The two base plates  102 ,  202  are connected with one another such that the ink supply lines  106 ,  206  form a continuous ink supply line. By connecting the two ink supply lines  106 ,  206 , ink is supplied in the arrow direction  16  from the ink supply line  106  of the first print head module  100  to the ink supply line  206  of the second print head module  200 . 
     Via a connector  208  of the second print head module  200 , ink is conveyed from an ink outlet opening of the ink supply line  206  into a connecting hose  214  that is connected with a connector  216  of the print head  204  accommodated in the second print head module  200 , such that ink is supplied in the arrow direction  18  from the ink supply line  206  to the second print head  204 . In an exemplary embodiment, the connectors  108 ,  116 ,  208 ,  216  are executed as hose fittings for the connection of a connecting line  114 ,  214 , wherein the hose fittings in the base plate  102 ,  202  are screwed in, inserted, welded onto the base plate  102 ,  202 , or soldered onto the base plate  102 ,  202 . The connecting line  114 ,  214  may in particular be executed as a connecting hose. In the described first exemplary embodiment, the ink supply line  206  is closed with a closure element  213  at the second opening  212 . 
       FIG. 2  shows a schematic side view of the print bar  10  according to  FIG. 1 . Elements having the same design or the same function have the same reference character. The first print head  104  and the second print head  204  respectively comprise a print nozzle region  120 ,  220  and a supply region  122 ,  222 . A respective ink chamber (not shown) is arranged in the supply region  122 ,  222 , which ink chamber is filled with ink or refilled with fresh ink via the connecting hose  114 ,  214 . In the print nozzle region  120 ,  220 , print nozzles are arranged which comprise nozzle channels via which ink is ejected in the form of ink droplets. A respective actuator is arranged in the ink chamber or in the nozzle channel of the print head  104 ,  204  to generate an ink droplet. The actuator is controlled by an actuator controller, depending on print data, with a control signal having a predetermined waveform to output an ink droplet, such that an ink droplet is ejected in the arrow direction  21  and a print dot is generated on a recording medium  22 . 
     In the first embodiment, the print nozzle region  120 ,  220  respectively extends along the entire width of the respective print head modules  100 ,  200  and protrudes from the base plate  102 ,  202  in the arrow direction  21 . The supply region  122 ,  222  of the print heads  104 ,  204  respectively has a smaller width than the respective print head module  100 ,  200 . A first region  124 ,  224  of the supply region  122 ,  222  is accommodated in the respective base plate  102 ,  220 ; a second region  126 ,  226  of the supply region  122 ,  222  protrudes from the respective print head module  100 ,  200  in the direction opposite the arrow direction  21 . The print nozzle regions  120 ,  220  are immediately adjoining one another. The adjacent print nozzles of the print nozzle region  120  and of the print nozzle region  220  are in particular aligned such that they are aligned in the print raster of the raster images to be printed. 
       FIG. 3  shows a schematic plan view of a print bar  20  having two print head modules  100 ′,  200 ′ according to a second embodiment. Elements having the same design or the same function have the same reference characters. The first print head module  100 ′ comprises a first carrier element  130 , the second print head module  200 ′ comprises a second carrier element  230 . In contrast to the first embodiment, the ink supply line  106  does not run in the base plate  102  but rather in a cutout of the first carrier element  130 . The ink supply line  206  accordingly also does not run in the base plate  202  but rather in a cutout of the second carrier element  230 . An especially good stability of the print head modules  100 ′,  200 ′ is achieved with the aid of the carrier elements  130 ,  230 . The carrier elements  130 ,  230  are connected among one another in the same manner as the base plates  102 ,  202 , in particular are glued with one another. 
       FIG. 4  shows a schematic front view of the print bar  20  according to  FIG. 3 , from a first side. The carrier elements  130 ,  230  are respectively arranged such that the middle lines M 2  of the carrier elements  130 ,  230  and the middle lines M 1  of the base plates  102 ,  202  form a 90° angle, so that the carrier elements  130 ,  230  and the base plates  102 ,  202  form the shape of an L profile. In the exemplary embodiment according to  FIG. 4 , the carrier elements  130 ,  230  and the respective base plates  102 ,  202  are formed as a single piece. Given alternative embodiments, the carrier elements  130 ,  230  and the respective base plates  102 ,  202  are separate components firmly connected with one another. In further embodiments, the carrier elements  130 ,  230  together with the base plates  102 ,  202  form a T-shaped cross section. 
       FIG. 5  shows a further schematic side view of the print bar  20  according to  FIG. 3 , from a second side. 
       FIG. 6  shows a schematic plan view of a print bar  30  having two print head modules  100 ″,  200 ″ according to a third embodiment. The print head modules  100 ″,  200 ″ differ from the print head modules  100 ,  200  of the first embodiment in that, in addition to the ink supply lines  106 ,  206  for supplying ink to the respective print heads  104 ″,  204 ″, a respective additional ink supply line  107 ,  207  for discharging ink from the respective print heads  104 ″,  204 ″ is integrated into the base plates  102 ″,  202 ″. The ink supply lines  106 ,  206  are referred to in the following as first ink supply lines; the ink supply lines  107 ,  207  are referred to in the following as second ink supply lines. 
     The supplying of the print heads  104 ′,  204 ′ with ink takes place in the same manner as is described in conjunction with  FIG. 1 . The first ink supply line  206  is, however, not closed at the second opening  212 . A hose fitting  221  is arranged at the second opening  212 , in particular is glued or screwed to the base plate  202 ′, which connects the first ink supply line  206  with a first end of a hose connection element  215 . 
     The base plates  102 ″,  202 ″ respectively comprise a third opening  113 ,  213  and a fourth opening  117 ,  217 , wherein the second ink supply line  107  for discharging ink travels between the third opening  113  and the fourth opening  117  of the base plate  102 ″ of the first print head module  100 ″, and the second ink supply line  207  for discharging ink travels between the third opening  213  and the fourth opening  217  of the second print head module  200 ″. A hose fitting  223  is arranged at the fourth opening  217  of the second print head module  200 ″, in particular is glued or screwed to the base plate  102 ″, which hose fitting  223  connects the second ink supply line  217  with a second end of the hose connection element  215 . In other embodiments, the second opening  212  and the fourth opening  217  are respectively closed by a closure element. 
     In addition to the connector  216 , which is a first connector  216  of the print head  204 ″, the print head  204 ″ comprises a second connector  217 . In addition to the connector  208 , which is a first connector  208  of the print head module  200 ″, the second print head module  200 ″ also comprises a second connector  209 . Via the second connector  217  of the print head  204 ″, ink is conveyed in a connecting hose  219  that is connected with the second connector  209  of the print head module  200 ″ so that ink may flow in the arrow direction  19  from the print head  204 ″ into the second ink supply line  207  via an ink inlet opening. 
     The third opening  213  of the base plate  202  of the second print head module  200 ″ adjoins the fourth opening  117  of the base plate  101  of the first print head module  100 ″. A connection between the second ink supply line  207  of the second print head module  200 ″ and the second ink supply line  107  of the first print head module  100 ″ is established via the openings  213 ,  117 . In an exemplary embodiment, the base plates  102 ″,  202 ″ are glued to one another so that the ink supply lines  107 ,  207  form a continuous ink supply line. Ink is thus supplied in the arrow direction  17  from the second ink supply line  207  of the second print head module  200 ″ to the second ink supply line  107  of the first print head module  100 ″. 
     In addition to the connector  116 , which is a first connector  116  of the print head  104 ″, the print head  104 ″ comprises a second connector  117 . In addition to the connector  108 , which is a first connector  108  of the first print head module  100 ″, the first print head module  100 ″ also comprises a second connector  109 . Via the second connector  117  of the print head  104 ″, ink is conveyed in a connecting hose  119  that is connected with the second connector  109  of the print head module  100 ″ so that ink from the print head  104 ′ is directed in the arrow direction into the second ink supply line  107  via an ink inlet opening. 
     A hose fitting  131  is arranged at the third opening  113  of the first print head module  100 ″, in particular is glued or screwed to the base plate  102 ″, which hose fitting  131  is connected at a first end with the second ink supply line  107  and at a second end with an external ink supply line  15  which connects the print head module  100 ″ with the ink supply unit  12 . The ink conveyed from the print heads  104 ″ and  204 ″ is supplied back in the arrow direction  17  into the ink supply unit  12  via the ink supply line  15 . Given the described third embodiment, a closed ink circuit is thus formed that ensures the supply of the print heads  104 ″,  204 ″ with fresh ink and the discharge of excess ink from the print heads  104 ″,  204 ″. 
       FIG. 7  shows a schematic side view of the print bar  30  according to  FIG. 6 . The first ink supply lines  106 ,  206  travel in the base plates  102 ″,  202 ″, respectively parallel to the second ink supply lines  107 ,  207 . 
       FIG. 8  shows a schematic plan view of a print bar  40  having two print head modules  100 ′″,  200 ′″ according to a fourth embodiment. Elements having the same design or the same function have the same reference characters. The supply of the ink to the print heads  104 ′″,  204 ′″ and the discharge of the ink from the print heads  104 ′″,  204 ′″ takes place in the manner described in the third embodiment. In the fourth embodiment, a respective first coolant supply line  156 ,  256  for supplying coolant to the respective print head  104 ′″,  204 ′″ travels in the base plate  102 ′″ of the first print head module  100 ′″ and in the base plate  202 ′″ of the second print head module  200 ′″. A respective second coolant supply line  156 ,  256  for discharging coolant from the respective print head  104 ′″,  204 ′″ also travels in the base plate  102 ′″ of the first print head module  100 ′″ and in the base plate  202 ′″ of the second print head module  200 ′″. 
     The first coolant supply line  156  of the first print head module  100 ′″ travels between a fifth opening  150  and a sixth opening  162  in the base plate  102 ′″. A hose fitting  151  is arranged at the fifth opening  150 , in particular is glued or screwed to the base plate  102 ′″, which hose fitting  151  connects the first coolant supply line  156  with an external coolant supply line  24 . Coolant is supplied in the arrow direction  16  from a coolant supply unit  23  to the first coolant supply line  156  via the external coolant supply line  24 . Via a third connector  158  of the first print head module  100 ′″, coolant is conveyed from a coolant outlet opening of the first coolant supply line  156  into a connecting hose  164  that is connected with a third connector  166  of the print head  104 ′″ so that coolant may flow in the arrow direction  18  into the print head  104 ′″. 
     The sixth opening  162  of the first print head module  100 ′″ adjoins the fifth opening  250  of the second print head module  200 ′″. A connection between the first coolant supply line  156  of the first print head module  100 ′″ and the first coolant supply line  256  of the second print head module  200 ′″ is established via the openings  162 ,  250 . In an exemplary embodiment, the two base plates  102 ′″,  202 ′″ are glued to one another so that the coolant supply lines  156 ,  256  form a continuous coolant supply line. Via the connection of the two coolant supply lines  156 ,  256 , coolant is conducted in the arrow direction  16  from the first coolant supply line  156  of the first print head module  100 ′″ into the first coolant supply line  256  of the second print head module  200 ′″. 
     Via a third connector  258  of the second print head module  200 ′″, coolant is conveyed from a coolant outlet opening into a connecting hose  264 , which is connected with a third connector  266  of the print head  204 ′″ so that coolant is supplied in the arrow direction  18  to the print head  204 ′″. 
     The first coolant supply line  256  travels between the fifth opening  250  and a sixth opening  262  of the second print head module  200 ′″. Arranged at the sixth opening  262  is a hose fitting  271  that connects the first coolant supply line  256  with a first end of a hose connection element  265 . 
     The base plates  102 ′″ and  202 ′″ respectively comprise a seventh opening  163 ,  263  and an eighth opening  167 ,  267 . The second coolant supply lines  157 ,  257  respectively run between the seventh opening  163 ,  263  and the eighth opening  167 ,  267 . Arranged at the eighth opening  267  of the second print head module  200 ′″ is a hose fitting  273  that connects the hose connection element  265  with the second coolant supply line  257  of the second print head module  200 ′″. 
     The print head  204 ′″ comprises a fourth connector  267  with the aid of which coolant is conveyed from the print head  204 ′″ into a connecting hose  269 . The connecting hose  269  is connected with a fourth connector  259  of the second print head module  200 ′″ so that coolant may flow in the arrow direction  19  from the print head  204 ′″ into the coolant supply line  257  via an ink inlet opening. 
     The seventh opening  263  of the second print head module  200 ′″ adjoins the eighth opening  167  of the first print head module  100 ′″. A connection between the second coolant supply lines  157 ,  257  is established via the openings  167 ,  263 . In an exemplary embodiment, with the base plates  102 ′″,  202 ′″ being glued to one another, the coolant supply lines  157 ,  257  form a continuous coolant supply line. Via this connection, coolant is supplied in the arrow direction  17  from the second coolant supply line  257  of the second print head module  200 ′″ into the second coolant supply line  157  of the first print head module  100 ′″. 
     The print head  204 ′″ comprises a fourth connector  167  with the aid of which coolant is conveyed from the print head  104 ′″ into a connecting hose  169 . The connecting hose  169  is connected with a fourth connector  159  of the first print head module  100 ′″ so that coolant may flow in the arrow direction  19  from the print head  104 ′″ into the coolant supply line  157  via a coolant inlet opening. 
     A hose fitting  181  is arranged at the seventh opening  163  of the first print head module  100 ′″, in particular is glued or screwed to the base plate  102 ′″, which hose fitting  181  connects the second coolant supply line  157  with an external coolant supply line  25  that connects the print head module  100 ′″ with a coolant supply unit  23 . A closed coolant circuit is thus formed in the described fourth exemplary embodiment. 
     The first coolant supply lines  156 ,  157  respectively have a smaller clearance from the ink supply lines  106 ,  206 ,  107 ,  207 , in a range between 1 mm and 2 cm, preferably between 2 mm and 5 mm. The ink within the print bar  100 ′″,  200 ′″ is thereby tempered such that the ink directed in the ink supply lines  106 ,  206 ,  107 ,  207  exhibits a temperature in a range between 29° C. and 32° C. 
       FIG. 9  shows a schematic side view of the print bar  40  according to  FIG. 8 . The ink supply lines  106 ,  206 ,  107 ,  207  travel in the base plates  102 ′″,  202 ′″, respectively parallel to coolant supply lines  156 ,  157 ,  256 ,  257 . 
       FIG. 10  shows a schematic plan view of a print bar  50  having two print head modules  300 ,  400  according to a fifth embodiment. Elements having the same design or the same function have the same reference characters. The base plates  302 ,  402  are respectively connected with two print heads  304 ,  304 ′,  404 ,  404 ′. The print head modules  300 ,  400  also respectively comprise a carrier element  330 ,  430  that is arranged centrally with respect to the respective print heads  304 ,  304 ′,  404 ,  404 ′. The middle plane M 2  of the carrier elements  330 ,  430  is respectively arranged at a 90° angle to the middle plane M 1  of the base plates  302 ,  402 , so that the carrier elements  330 ,  430 , with the base plates  302 ,  402 , form the shape of a T-profile. 
     The first ink supply lines  106 ,  206  for supplying ink to the print heads  304 ,  304 ′,  404 ,  404 ′, and the second ink supply lines  107 ,  207  for discharging ink from the print heads, respectively run in cutouts of the carrier elements  330 ,  430 . The supplying of the print heads  304 ,  304 ′,  404 ,  404 ′ with ink, and the discharging of in from the print heads  304 ,  304 ′,  404 ,  404 ′, take place in the manner described in conjunction with the third embodiment, with the difference that the ink supply lines  106 ,  206 ,  107 ,  207  run in the carrier elements  330 ,  430  and supply four print heads  304 ,  304 ′,  404 ,  404 ′. In each print head module  300 ,  400 , two respective connectors  108 ,  108 ′,  208 ,  208 ′ are thus provided for discharging ink from the ink supply line  106 ,  206 , and two respective connectors  109 ,  109 ′,  209 ,  209 ′ are provided for supplying ink into the ink supply line  206 ,  207 . The connectors  108 ,  108 ′,  208 ,  208 ′,  109 ,  109 ′,  209 ,  209 ′ are connected via connecting hoses  114 ,  114 ′,  214 ,  214 ′,  119 ,  119 ′,  219 ,  219 ′ with a respective corresponding connector  116 ,  116 ,  117 ,  117 ′,  216 ,  216 ′,  217 ,  217 ′ of the print heads  304 ,  304 ′,  404 ,  404 ′. 
     In an alternative embodiment, the coolant supply lines  156 ,  157 ,  256 ,  257  also run in the carrier elements  330 ,  430 . In a further alternative embodiment, the ink supply lines  106 ,  206 ,  107 ,  207  run in the base plates  302 ,  402  and the coolant supply lines  156 ,  157 ,  256 ,  257  run in the carrier elements  330 ,  430 . In a further alternative embodiment, the coolant supply lines  156 ,  157 ,  256 ,  257  run in the base plates  302 ,  402  and the ink supply lines  106 ,  206 ,  107 ,  207  run in the carrier elements  330 ,  430 . 
       FIG. 11  shows a schematic view of a print bar  50  according to  FIG. 10 , from below. Elements having the same design or the same function have the same reference characters. The print nozzle regions  120 ,  120 ′,  220 ,  220 ′ respectively extend over the entire width B of the print head modules  300 ,  400 . The print nozzles of the print heads  304 ,  304 ′,  404 ,  404 ′ of a print head module  300 ,  400  respectively print the same color. A doubled printing speed is thereby achieved relative to a printing with one print head per print head module. In alternative embodiments, the print heads  304 ,  304 ′,  404 ,  404 ′ of a print head module  300 ,  400  may respectively print different colors. Additional ink supply lines must be correspondingly provided for this. 
       FIG. 12  shows a schematic view of a print bar  60  having five print head modules  500 ,  600 ,  700 ,  800 ,  900 . Elements having the same design or the same function have the same reference characters. Accommodated in each print head module  500 ,  600 ,  700 ,  800 ,  900  is a respective print head  504 ,  604 ,  704 ,  804 ,  904  whose print nozzle region  520 ,  620 ,  720 ,  820 ,  920  extends over a partial region of the respective base plate  502 ,  602 ,  702 ,  802 ,  902 . The print head modules  500 ,  600 ,  700 ,  800 ,  900  are connected such that the print head modules  500 ,  600 ,  700  are arranged in a first row R 1  and the print head modules  800 ,  900  are arranged in a second row R 2 . The print nozzle regions  520 ,  620 ,  720 ,  820 ,  920  are thereby arranged within a row R 1 , R 2 , respectively spaced apart from one another. The print nozzle regions  520 ,  620 ,  720  of the first row R 1  are arranged with an offset from the print nozzle regions  820 ,  920  of the second row, such that a respective overlap region U 1  to U 4  is formed in which the print nozzles of two print heads  504 ,  604 ,  704 ,  804 ,  904 . 
     In an alternative embodiment, retaining elements may be provided for stabilizing the print bar  50 , which retaining elements in particular stabilize the border regions of the second row R 2 . 
       FIG. 13  shows a seventh embodiment in which the print bar  10  is introduced into a rail S. The print head modules  100 ,  102  introduced into the rail S may be connected, in particular materially connected, with the rail S. 
     In further alternative embodiments, more than two print head modules  100  to  100 ′″,  200  to  200 ′″,  300  to  900 , in particular five, fifteen, or twenty print head modules  100  to  100 ′″,  200  to  200 ′″,  300  to  900 , are connected to a print bar. 
     To enable those skilled in the art to better understand the solution of the present disclosure, the technical solution in the embodiments of the present disclosure is described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the embodiments described are only some, not all, of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art on the basis of the embodiments in the present disclosure without any creative effort should fall within the scope of protection of the present disclosure. 
     It should be noted that the terms “first”, “second”, etc. in the description, claims and abovementioned drawings of the present disclosure are used to distinguish between similar objects, but not necessarily used to describe a specific order or sequence. It should be understood that data used in this way can be interchanged as appropriate so that the embodiments of the present disclosure described here can be implemented in an order other than those shown or described here. In addition, the terms “comprise” and “have” and any variants thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or equipment comprising a series of steps or modules or units is not necessarily limited to those steps or modules or units which are clearly listed, but may comprise other steps or modules or units which are not clearly listed or are intrinsic to such processes, methods, products or equipment. 
     References in the specification to “one embodiment,” “an embodiment,” “an exemplary embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     The exemplary embodiments described herein are provided for illustrative purposes, and are not limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments. Therefore, the specification is not meant to limit the disclosure. Rather, the scope of the disclosure is defined only in accordance with the following claims and their equivalents. 
     Embodiments may be implemented in hardware (e.g., circuits), firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact results from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc. Further, any of the implementation variations may be carried out by a general-purpose computer. 
     For the purposes of this discussion, the term “processing circuitry” shall be understood to be circuit(s) or processor(s), or a combination thereof. A circuit includes an analog circuit, a digital circuit, data processing circuit, other structural electronic hardware, or a combination thereof. A processor includes a microprocessor, a digital signal processor (DSP), central processor (CPU), application-specific instruction set processor (ASIP), graphics and/or image processor, multi-core processor, or other hardware processor. The processor may be “hard-coded” with instructions to perform corresponding function(s) according to aspects described herein. Alternatively, the processor may access an internal and/or external memory to retrieve instructions stored in the memory, which when executed by the processor, perform the corresponding function(s) associated with the processor, and/or one or more functions and/or operations related to the operation of a component having the processor included therein. 
     In one or more of the exemplary embodiments described herein, the memory is any well-known volatile and/or non-volatile memory, including, for example, read-only memory (ROM), random access memory (RAM), flash memory, a magnetic storage media, an optical disc, erasable programmable read only memory (EPROM), and programmable read only memory (PROM). The memory can be non-removable, removable, or a combination of both. 
     REFERENCE LIST 
     
         
         print bar  10 ,  20 ,  30 ,  40 ,  50   
         print head module  100 ,  100 ′,  100 ″,  100 ′″,  200 ,  200 ′,  200 ″,  200 ′″,  300 ,  400 ,  500 ,  600 ,  700 ,  800 ,  900   
         base plate  102 ,  102 ′,  102 ″,  102 ′″,  202 ,  202 ′,  202 ″,  202 ′″,  302 ,  402 ,  502 ,  602 ,  702 ,  802 ,  902   
         print head  104 ,  104 ′,  104 ″,  104 ′″,  204 ,  204 ′,  204 ″,  204 ′″,  304 ,  404 ,  504 ,  604 ,  704   804 ,  904   
         ink supply line  14 ,  15 ,  106 ,  107 ,  206 ,  207   
         opening  110 ,  112 ,  113 ,  117 ,  150 ,  162 ,  163 ,  167 ,  210 ,  212 ,  213 ,  217 ,  250 ,  262 ,  263 ,  267   
         hose fitting  111 ,  151 ,  181 ,  221 ,  223 ,  271 ,  273 , 
         hose connection element  215 ,  265   
         connecting hose  114 ,  114 ′,  119 ,  119 ′,  164 ,  169 ,  214 ,  214 ′,  219 ,  219 ′,  264 ,  269 , 
         coolant supply line  24 ,  25 ,  156 ,  157 ,  256 ,  257   
         coolant supply unit  23   
         connector  108 ,  109 ,  109 ′,  108 ′,  116 ,  116 ′,  117 ′,  158 ,  166 ,  167 ,  208 ,  208 ′,  209 ,  209 ′,  216 ,  216 ′,  217 ,  217 ′,  209 ,  258 ,  266 ,  267 ,  259   
         closure element  213   
         supply region  122 ,  222   
         print nozzle region  120 ,  220 ,  520 ,  620 ,  720 ,  820 ,  920   
         carrier element  130 ,  230 ,  330 ,  430   
         arrow direction  16 ,  17 ,  18 ,  19 ,  21   
         width B 
         overlap region U 1  to U 4   
         row R 1 , R 2   
         middle plane M 1 , M 2   
         angle A 
         rails S