Patent Publication Number: US-11654699-B2

Title: Dryer system with exhaust gas purification

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to German Patent Application No. 10 2020 112 042.7, filed May 5, 2020, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Field 
     The disclosure relates to a dryer system for drying a recording medium that has been printed to, in particular for use in an inkjet printing device. 
     Inkjet printing devices may be used to print to recording media, for example paper. For this purpose, one or more nozzles are used in order to fire ink droplets onto the recording medium, and thus to generate a desired print image on the recording medium. 
     An inkjet printing device may comprise one or more dryer systems in order to dry the recording medium after application of the print image, and to thereby fix the applied ink on the recording medium. A dryer system may have a drying route with a plurality of dryers. The individual dryers may be configured to blow a heated, gaseous drying medium, in particular air, onto the surface of the recording medium in order to dry said recording medium. The dryers may thereby be arranged along the drying route such that the recording medium does not come into contact with the dryers and floats through the dryer system. 
     Within the scope of the drying of a recording medium, the other substances, in particular solvents, in addition to water are extracted from the recording medium. It is thereby typically to be ensured that no flammable gases accumulate in the housing of the dryer systems, such that a dryer system for the most part has a relatively high air mass flow, which leads to a relatively high power consumption. 
    
    
     
       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    a block diagram of an inkjet printer having a dryer or fixer according to an exemplary embodiment. 
         FIG.  1   b    a block diagram of a dryer system for an inkjet printer according to an exemplary embodiment. 
         FIG.  1   c    a block diagram of a dryer for a dryer system according to an exemplary embodiment. 
         FIG.  2   a    an example of a dryer system having a wet scrubber according to an exemplary embodiment. 
         FIG.  2   b    an example of a dryer system having a wet scrubber and a recirculation of gaseous drying medium according to an exemplary embodiment. 
         FIG.  3    a wet scrubber according to an exemplary embodiment. 
         FIG.  4    a flowchart of a method for drying a recording medium according to an exemplary embodiment. 
     
    
    
     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. 
     The present document deals with the technical object of providing an energy-efficient, safe, and environmentally friendly dryer system for a reliable drying of a recording medium. 
     According to one aspect of the disclosure, a dryer system is described for drying a recording medium that has been printed to. The dryer system comprises a housing having at least one dryer that is configured to apply thermal energy to the recording medium in order to extract moisture from said recording medium. The dryer system also comprises a ventilator that is configured to direct an exhaust gas with the moisture out of the housing, to a wet scrubber. Furthermore, the dryer system comprises the wet scrubber that is configured to purify the exhaust gas. 
     According to a further aspect of the disclosure, a method is described for drying a recording medium that has been printed to. The method includes the application of thermal energy to the recording medium in a housing of a dryer system in order to extract moisture from said recording medium. Furthermore, the method includes directing an exhaust gas with the moisture out of the housing, to a wet scrubber, and the purification of the exhaust gas using the wet scrubber. 
     The printing device (printer)  100  depicted in  FIG.  1   a    is configured to print to a recording medium  120  in the form of a sheet or page or plate or belt. The recording medium  120  may be produced from paper, paperboard, cardboard, metal, plastic, textiles, a combination thereof, and/or other materials that are suitable and can be printed to. The recording medium  120  is directed along the transport direction  1 , represented by an arrow, through the print group  140  of the printing device  100 . 
     In the depicted example, the print group  140  of the printing device  100  comprises two print bars  102 , wherein each print bar  102  may be used for printing with ink of a defined color, for example black, cyan, magenta, and/or yellow, and if applicable MICR ink. Furthermore, the printing device  100  comprises at least one fixing or dryer system  150  that is configured to fix a print image printed onto the recording medium  120 . 
     A print bar  102  may comprise one or more print heads  103  that, if applicable, are arranged side by side in a plurality of rows in order to print the dots of different columns  31 ,  32  of a print image onto the recording medium  120 . In the example depicted in  FIG.  1   a   , a print bar  102  comprises five print heads  103 , wherein each print head  103  prints the dots of a group of columns  31 ,  32  of a print image onto the recording medium  120 . 
     In the embodiment depicted in  FIG.  1   a   , each print head  103  of the print group  140  comprises a plurality of nozzles  21 ,  22 , wherein each nozzle  21 ,  22  is configured to fire or eject ink droplets onto the recording medium  120 . A print head  103  of the print group  140  may, for example, comprise multiple thousands of effectively utilized nozzles  21 ,  22  that are arranged along a plurality of rows transverse to the transport direction  1  of the recording medium  120 . By the nozzles  21 ,  22  of a print head  103  of the print group  140 , dots of a line of a print image may be printed onto the recording medium  120  transverse to the transport direction  1 , meaning along the width of the recording medium  120 . 
     The printing device  100  also comprises a controller  101 , for example an activation hardware and/or a controller, that is configured to activate the actuators of the individual nozzles  21 ,  22  of the individual print heads  103  of the print group  140  in order to apply the print image onto the recording medium  120  depending on print data. In an exemplary embodiment, the controller  101  includes processing circuitry that is configured to perform one or more functions and/or operations of the controller  101 . 
     The print group  140  of the printing device  100  thus comprises at least one print bar  102  having K nozzles  21 ,  22  that may be activated with a defined line timing in order to print a line traveling transverse to the transport direction  1  of the recording medium  120  with K pixels or K columns  31 ,  32  of a print image onto the recording medium  120 , for example with K&gt;1000. In the depicted example, the nozzles  21 ,  22  are immobile or permanently installed in the printing device  100 , and the recording medium  120  is directed past the stationary nozzles  21 ,  22  with a defined transport velocity. 
     As presented above, the printing device  100  may comprise a dryer system  150  that is configured to dry the recording medium  120  after application of the ink via the one or more print bars  102 , and therewith to fix the applied print image on the recording medium  120 . For this purpose, the dryer system  150  may be controlled by a controller  101  of the printing device  100 . For example, the drying may take place depending on the quantity of applied ink and/or depending on a type of the recording medium  120 . For example, the temperature and/or the volumetric flow of the gaseous drying medium may be adapted depending on the quantity of applied ink and/or depending on a type of the recording medium  120 . 
     The dryer system  150  depicted in  FIG.  1   b    comprises a plurality of dryers  160  that are arranged on both sides of the recording medium  120  (typically in the form of a belt) along a drying route, and that are respectively configured to blow a gaseous drying medium, typically heated air, onto the surface of the recording medium  120 . The drying route with the dryers  160  is thereby arranged in a housing  155  of the dryer system  150 . By blowing with a gaseous drying medium, the print image on a recording medium  120  may be gently and reliably dried along the drying route of the dryer system  150 . 
       FIG.  1   c    shows a block diagram with examples of components of a dryer  160 . The dryer  160  depicted in  FIG.  1   c    comprises a blower  165  with which a gaseous medium, in particular air, may be directed past one or more heaters  162 . Alternative or additional measures for generating a heated drying medium  164  are possible (for example the use of a gas burner). The drying medium  164  heated by the heaters  162  is then blown via one or more openings or nozzles  163  onto the surface of the recording medium  120 . The one or more nozzles  163  may respectively be round-hole spinnerets, whereby a particularly good thermal transfer from the heated drying medium  164  to the recording medium  120  may be produced. The discharge rate of the blower  165  and/or the heating capacity of the one or more heaters  162  may be controlled or regulated via a controller  161  of the dryer  160 , wherein the controller  161  may, if applicable, be part of the controller  101  of the dryer  160  or of the printing device  100 . In an exemplary embodiment, the controller  161  includes processing circuitry that is configured to perform one or more functions and/or operations of the controller  161 . In particular, the temperature in the environment of the recording medium  120  may be detected using a temperature sensor  166 . The controller  161  may be configured to control or regulate the blower  165  and/or the one or more heaters depending on sensor data of the temperature sensor  166 . For example, a defined temperature may thus be set in the environment of the recording medium  120 . 
     A contactless float drying using forced convection may thus be used to dry a recording medium  120 . As depicted in  FIG.  1   b   , for this purpose the individual dryers  160  are arranged alternating on the front side and the back side of the recording medium  120  along the drying route. The recording medium  120  may then be pushed and/or pulled, floating past the dryers  160 , through the dryer system  150 . 
     During the drying, water vapor and solvent vapor escape from the recording medium  120 . A gas mixture of water vapor and solvent vapor is thus created in the housing  155  of the dryer system  150 . The gas mixture may be conveyed out of the housing  155  with a ventilator in order to avoid a flammable gas mixture forming inside said housing  155 , and in order to remove the moisture from the housing  155  of the dryer system  150 . In this document, the gas mixture is also referred to as exhaust gas. 
       FIGS.  2   a  and  2   b    respectively show a dryer system  150  having a wet scrubber  210  that is configured to purify the gas mixture extracted from the housing  155  of the dryer system  150 . The gas mixture  208  may be extracted from the housing  155  of the dryer system  150  using a ventilator  203 . The gas mixture  205  purified by the wet scrubber  210  may be discharged into the environment, as depicted in  FIG.  2   a   , or be resupplied as a gaseous drying medium  164  to the one or more dryers  160 , as depicted in  FIG.  2   b   . For this purpose, a ventilator  207  may be used that directs the purified gas mixture  205  to the one or more dryers  160  in the housing  155  of the dryer system  150 . 
     The dryer system  150  may comprise a heat exchanger  202  that is configured to heat the gaseous drying medium  164  before reaching the one or more dryers  160 . In the wet scrubber  210 , the thermal energy may thereby be extracted from the gas mixture  208  from the housing  155  of the dryer system  150  and be supplied to the gaseous drying medium  164  in the heat exchanger  202 . For this purpose, one or more conduits  206  may be arranged between the wet scrubber  210  and the heat exchanger  202 . The energy efficiency of the dryer system  150  may be increased via the use of a heat exchanger  202 . 
       FIG.  3    shows an example of a wet scrubber  210 . The wet scrubber  210  may comprise a washing chamber in which is formed a curtain of droplets  304  of a cleaning fluid. The curtain of cleaning fluid droplets  304  may be generated by one or more porous conduits  303 , for example, that are arranged on the top side and/or on the underside of the washing chamber  302 , for example, and through which the cleaning fluid is pumped from a supply conduit  309  into the washing chamber  302 . 
     The gas mixture  208  to be purified is directed through the washing chamber  302 , wherein solvent from the gas mixture  208  is captured by the cleaning fluid droplets  304  and thus is removed from the gas mixture  208 . The washing chamber  302  has on the floor a capture basin  305  in which the cleaning fluid  301  with the solvent (for example ethylene glycol) is collected. The captured cleaning fluid  301  is thereby warmed by the heated gas mixture  208  and may be directed via the conduit  206  to the heat exchanger  202  in order to transfer thermal energy from the gas mixture  208  to the gaseous drying medium  164 . 
     The gas mixture  208  may be filtered via a filter  308 , if applicable on the top side of the washing chamber  302 , in order to further purify the gas mixture  208 . The gas mixture  208  may also be directed to a fluid separator  306  that, for example, operates according to the cyclone principle in order to remove fluid  307 , in particular water, from the gas mixture  208 . The purified gas mixture  205  may then be provided at the output of the fluid separator  306 . The fluid  307  extracted from the gas mixture  208  may be used as cleaning fluid in the wet scrubber  210 . 
     A dryer system  150  is thus described having a wet scrubber  210  for exhaust air treatment. The reduction of the solvent content in the exhaust air, i.e. in the gas mixture  208  to be purified or in the exhaust gases  208 , may thereby be produced via the use of a wet scrubber  210 . 
     Furthermore, a reduction in the concentration of solvent in the dryer housing  155  may be produced in order to ensure a safer operation of the dryer system  150  and in order to continuously maintain a high drying effect. 
     Thermal energy may be extracted from the exhaust air  208  via use of a heat exchanger, in particular of an air-water heat exchanger. The wet scrubber  210  may thereby be used as a heat exchanger. A media separation between the exhaust air  208  and the cleaning fluid  301  to be captured is thereby typically unnecessary, since water vapor is already contained in the exhaust air  208 , and a certain content of solvent, which has a higher boiling point than water, typically does not interfere with the cooling and condensation process in the washing chamber  302 . The effectiveness of the heat transfer, and therefore the condensation performance, improves due to omitting the separating wall of the heat exchanger. 
     In the purification of exhaust air, the washing solution at the fluid distributor should have an optimally low temperature. The productive capacity of the exhaust gas purification may be adjusted via the droplet size of the droplets  304  and via the residence time of the exhaust air  208  in the washing chamber  302  or washing column. The substance having the higher boiling point, i.e. the solvent, for instance ethylene glycol having a boiling point of 197° C., preferentially condenses on the droplets  304 . The smaller the droplets  304 , the larger the surface area available for condensation. Given a droplet size of 110 μm, for example, 1 liter of water has a surface area of 5.45 m 2 ; given a droplet size of 12 μm, 1 liter of water already has a surface area of 50.2 m 2 . The purification effect may thus be increased via the use of relatively small droplets  304 . 
     The possible entrainment of washing solution, i.e. cleaning fluid, in the exhaust air flow may be prevented by a cyclone separator and/or a different droplet separator  306 , for example. The cooling of the washing solution may take place via a water/water heat exchanger or via a water/air heat exchanger. In the latter instance, the exhaust air  205  of the heat exchanger may be used as a supply air of the dryer system  150 , so that the total energy demand of the dryer system  150  may be further reduced. 
     As depicted in  FIG.  2   b   , a wet scrubber  210  may be directly integrated into the air circuit of the dryer system  150 . In this instance as well, heat recovery is possible in the cooling of the washing solution and may lead to a reduction of the total energy demand of the dryer system  150 . 
     Furthermore, a combination of the arrangements shown in  FIGS.  2   a  and  2   b    into a common wet scrubber  210  is possible. 
       FIG.  4    shows a waveform diagram of an example of a method  400  for drying a recording medium  120  that has been printed to. The method  400  includes the introduction or application  401  of thermal energy to the recording medium  120  in the housing  155  of a dryer system  150  in order to extract moisture from said recording medium  120 , and in order to thereby dry the recording medium  120  or the print image on the recording medium  120 . The thermal energy may, for example, be applied via application of a heated, gaseous drying medium  164  at the recording medium  120 . 
     Within the scope of the drying, exhaust gases  208  are typically created that, for example as water vapor, comprise the moisture that was extracted from the recording medium  120 . Moreover, the exhaust gases  208  may comprise contaminants, in particular solvent vapor. The method  400  also comprises the conducting  402  of the exhaust gas  208  with the moisture from the housing  155  to a wet scrubber  210 . Moreover, the method  400  comprises the purification  403  of the exhaust gas  208  in the wet scrubber  210 . 
     Within the scope of the purification of the typically warm exhaust gases  208 , thermal energy may be extracted from said exhaust gases  208 . In particular, thermal energy may be transferred from the exhaust gases  208  to the cleaning fluid  301  of the wet scrubber  210 . The thermal energy may then in turn be used to dry the recording medium  120  or to dry a subsequently recording medium  120 . An environmentally friendly and energy-efficient drying of a recording medium  120  may thus be produced. 
     A dryer system  150  for drying a recording medium  120  that has been printed to is thus described. The dryer system  150  may be part of an inkjet printing device  100 . 
     The dryer system  150  comprises a housing  155  having at least one dryer  160  that is configured to introduce or apply thermal energy to the recording medium  120  in order to extract moisture from the recording medium  120 . A great deal of moisture may thereby be extracted from the recording medium  120 , and in particular the print image on the recording medium  120 , such that said recording medium  120  is dried at the output of the housing  155  of the dryer system  150 . 
     The dryer system  150  may comprise a plurality of dryers  160  within the housing  155  that are arranged on different sides of the recording medium  120  such that a drying route is formed by the dryers  160 , along which drying route the recording medium  120  is directed without contact past the dryers  160 . The individual dryers  160  may thereby be configured to respectively blow a heated, gaseous drying medium  164  onto the recording medium  120  in order to extract moisture from said recording medium  120 . The dryer system  150  may thus be configured for a float drying of the recording medium  120 . A particularly gentle drying of the recording medium  120  may thus be produced. 
     The dryer system  150  also comprises a ventilator  203  that is configured to direct an exhaust gas  208  with the moisture extracted from the recording medium  120  out of the housing  155 , to a wet scrubber  210 . Due to the drying of the recording medium  120 , exhaust gases  208  may form inside the housing  155  of the dryer system  150 , which exhaust gases  208  may be guided by the ventilator  203  out of the housing  155 , to a wet scrubber  210 . In addition to the moisture, meaning in addition to water vapor, the exhaust gases  208  thereby typically also comprise contaminants, in particular solvents. 
     The wet scrubber  210  of the dryer system  150  is configured to purify the exhaust gas or exhaust gases  208  from the housing  155  of the dryer system  150 . The purified exhaust gases  205  may then be directed into the environment, or may possibly be directed at least in part back into the housing  155  of the dryer system  150 . A particularly environmentally safe drying of a recording medium  120  may be produced via the provision of wet scrubber  210 . 
     The wet scrubber  210  may be configured to extract thermal energy from the exhaust gas  208  from the housing  155  of the dryer system  150  and supply it to the dryer  160 . For this purpose, the wet scrubber  210  may be configured as a heat exchanger, in particular as a gas-fluid heat exchanger, between the exhaust gases  208  and the cleaning fluid  301  of the wet scrubber  210 . Furthermore, the dryer system  150  may comprise a heat exchanger  202 , in particular a fluid-gas heat exchanger, which is configured to heat the gaseous drying medium  164  using thermal energy that has been extracted from the exhaust gas  208  by the wet scrubber  210 . 
     The wet scrubber  210  may thus be used to recuperate thermal energy from the exhaust gases  208 , and to dry the recording medium  120  or a subsequent recording medium  120 . A particularly energy-efficient drying may thus be enabled. 
     A dryer system  150  is thus described that is configured to purify, using a wet scrubber  210 , exhaust gases  208  created in the drying of a recording medium  120  that has been printed to. Moreover, thermal energy may be extracted from the exhaust gases  208  in the wet scrubber  210 , which thermal energy is used in turn to dry the recording medium  120 . An environmentally safe and energy-efficient drying may thus be enabled. 
     The wet scrubber  210  may comprise a washing chamber  302 . Furthermore, the wet scrubber  210  may be configured to form a plurality of droplets  304  from cleaning fluid in the washing chamber  302 . The wet scrubber  210  may also be configured to direct the exhaust gas  208  from the housing  155  of the dry  150  through the washing chamber  302 , past the plurality of droplets  304  of cleaning fluid, in order to have the effect that contaminants, in particular solvents, are removed from the exhaust gas  208  via droplets  304  of cleaning fluid, in particular in order to have the effect that contaminants, in particular solvents, condense out of the exhaust gas  208  onto droplets  304  of cleaning fluid. A reliable purification of the exhaust gases  208  may thus be produced. 
     Moreover, the wet scrubber  210  may be configured such that, in the washing chamber  302 , thermal energy transfers from the exhaust gas  208  to the cleaning fluid  301 . This may be produced in particular via the condensation of the contaminant on the droplets  304  of cleaning fluid. The heat exchanger  202  of the dryer system  150  may then be configured to extract thermal energy from the cleaning fluid  301  heated by the exhaust gas  208 , which cleaning fluid  301  typically also contains the contaminants from the exhaust gases  208 , and to supply said thermal energy to the at least one dryer  160 , in particular to the gaseous tempering medium  164 . A particularly energy-efficient operation of the dryer system  150  may thus be enabled. 
     The dryer system  150  may be configured to supply exhaust gases  205  purified by the wet scrubber  210  from the housing  155  of the dryer system  150  to the at least one dryer  160  as a heated, gaseous drying medium  164  to dry the recording medium  120 . The energy efficiency of the drying may be further increased via the recirculation of the purified exhaust gases  205 . 
     The wet scrubber  210  may a comprise filter  308  that is configured to filter the exhaust gases  208  from the housing  155  of the dryer system  150  after traversing the washing chamber  302  of the wet scrubber  210 . The filter  308  may comprise a lamella separator and/or a wire mesh separator. Alternatively or additionally, the wet scrubber  210  may comprise a fluid separator  306  that is configured to remove fluid from the exhaust gases  208  after the exhaust gases  208  have traversed the washing chamber  302  of the wet scrubber  210 . A particularly reliable purification of the exhaust gases  208  may thus be produced. 
     In this document, an inkjet printing device  100  is also described that comprises a print group  140  that is configured to print a print image on a recording medium  120 . The printing device  100  comprises the dryer system  150  described in this document, which dryer system  150  is configured to dry the print image on the recording medium  120 . 
     The effectiveness in the removal of flammable and/or ecologically harmful solvents from the drying process may be increased via the use of a wet scrubber  210 . In particular, the effectiveness of the condensation of solvents may be significantly increased via the use of a relatively large interface between gas and fluid in a wet scrubber  210 , in particular in comparison to the use of heat exchangers with a separation between air and water. The thermal energy transferred via the condensation heat to the cleaning fluid  301  may be used by an air-water heat exchanger  202  for preheating the gaseous drying medium  164 . 
     The necessary air throughput of a dryer system  150  may be reduced via an improved condensation of the flammable solvent from the gas mixture  208  to be purified. This leads to a reduced energy requirement, since a reduced quantity of air (i.e. of drying medium  164 ) needs to be heated to process temperature. Additionally, the heat exchanger surface in a wet scrubber  210  cannot be contaminated, since this surface is continuously reformed via the droplet formation. 
     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 
     
         
           1  transport direction 
           21 ,  22  nozzle (print image) 
           31 ,  32  column (of the print image) 
           100  printing device (printer) 
           101  controller 
           102  print bar 
           103  print head 
           120  recording medium 
           140  print group 
           150  fixer or dryer system 
           160  dryer 
           161  controller 
           162  heating element (heater) 
           163  nozzle 
           164  tempered drying medium (air) 
           165  blower 
           166  temperature sensor 
           202  heat exchanger 
           203  blower 
           205  purified exhaust gases 
           206  conduit 
           207  ventilator 
           208  exhaust gases to be purified 
           210  wet scrubber 
           301  heated and contaminated cleaning fluid 
           302  washing chamber 
           303  porous conduit 
           304  droplets of cleaning fluid 
           305  capture basin 
           306  fluid separator 
           307  separated fluid 
           308  filter 
           309  supply line for cleaning fluid 
           400  method for drying a recording medium 
           401 - 403  method steps