Patent Publication Number: US-9840073-B2

Title: Drying device, system comprising a drying device and method for operating a drying device for drying between inking units of a printing machine

Description:
RELATED APPLICATIONS 
     This application is a National Phase of PCT Patent Application No. PCT/EP2013/072645 having International filing date of Oct. 29, 2013, which claims the benefit of priority of German Patent Application No. 10 2013 101 350.3 filed on Feb. 12, 2013. The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety. 
     FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to a drying device for a drying between inking units of a printing machine and a system with said drying device. Further, the invention relates to a method for operating said drying devices. 
     It is known from the state of the art to intend drying devices between the inking units of a printing machine in order to dry the colouring agent applied to the substrate. Further, it is known that the drying capacity of the drying device is adjusted by an operator. In one possible embodiment the drying device can be equipped with a blower, which supplies air into the direction of the substrate during drying. From the state of the art it is known that the operator can adjust the blow air speed and/or blow air temperature individually. With solvent based colouring agents the air supply used for drying is also used for discharging/diluting of solvent vapours. High requirements are made during the printing process of the printing machine to the adjustment of differently constructed drying devices. Already during adjusting of the printing machine the operator has to carry out adjustments at the drying device in order to be able to produce the required quality at a particularly small amount of time and number of waste runs. An adjustment of the drying capacity chosen too high requires not only a high energy consumption but hereby, disadvantageously, also the printing process can be negatively influenced. An adjustment of the drying capacity chosen too low has to be avoided since otherwise the risk of spreading the recently printed substrate is created during the transport over the rotating cylinder. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to avoid the previously described disadvantages, particularly to establish a drying device, a system with a drying device and a method for operating a drying device so that significant energy savings are achievable during the operation of the drying process and at the same time a high printing quality is ensured. 
     Said object is solved by a drying device with all features of claim  1 . Preferred embodiments of the invention are indicated in the dependent claims. Further, the invention is solved by a system with all features of claim  5 . In the dependent claims  6  to  9 , and  11  preferred embodiments of the system according to the invention are intended. Further, the object is solved by a method according to all features of claim  12 . In the dependent claims possible embodiments are described. 
     According to the invention a drying device is intended for a drying between inking units of a printing machine, by which a substrate is transportable via rotating cylinders and printable with colouring agents, wherein the drying device comprises an air supply unit for supplying of air in the direction of a substrate in order to cause a drying of the colouring agent. Further, the drying device according to the invention comprises a suction unit for discharging of air, wherein according to the invention a control unit is intended, which controls and/or regulates the air supply unit in dependence of operating parameters in a way that alterable drying areas are adjustable at the substrate. It is particularly preferable that the control unit can adjust or alter the arising drying areas individually from the printing image at the substrate. Between each inking unit of the printing machine preferably a drying device is intended. It is possible that diverse alterable drying areas occur between the inking units since each inking unit individually applies its own printing images to the substrate, which differ from the printing images of the remaining inking units. The operating parameters can be quantities, which are already saved within the printing machine particularly the drying device. Likewise the invention comprises operating parameters, which are determined and/or measured and/or calculated during the operation of the printing machine particularly the drying device. Likewise a combination of said operating parameters is possible. The printing machine can also involve for example a flexographic printing machine, with which according of the invention the energy consumption can be significantly reduced via the automatic adjustment of the drying areas, wherein at the same time the solvents in the colouring agent, like for example ethanol, etc. can be effectively extracted from the substrate. The handle for the operator is further significantly facilitated since the drying device automatically adjusts the drying capacity in dependence from the printing image, which is defined by the colouring agent on the substrate. Therewith an intelligent drying control can be established, which automatically adjusts different drying areas between each inking unit of the printing machine. Via the operating parameters the air supply unit and/or the suction unit is controlled and/or regulated intelligently so that an adjustment of the drying capacity is almost excluded, which was chosen too high or too low, wherein the energy input of the drying device according to the invention can be optimized during the drying or during the operation of the printing machine. 
     Advantageously the air supply unit can comprise movably flaps, wherein an alterable flow direction is achievable for the discharge of air from the air supply unit. For example it is possible that the width of the air supply unit mainly corresponds to the width of the substrate. 
     Likewise it can be intended that the width of the air supply unit is individually adjustable corresponding to the width of the to be transported substrate. This applies for the suction unit accordingly, which can be assembled together with the air supply unit in a common component. The flaps can for example be regulated and/or controlled via the control unit, wherein one or multiple flaps can be completely closed so that at these positions no air can flow from the drying device in the direction of the substrate. According to the position of the flaps the flow direction of the air can be individually adjusted, wherein different drying areas adjust between the substrate and the drying device, particularly the air supply unit and/or the suction unit. 
     Advantageously multiple modules can be intended, which each comprise an air supply unit and a suction unit, wherein the modules are individually controllable by the control unit particularly that the volume flow and/or the temperature and/or the flow direction of the discharging air in the direction of the substrate of each module is individually adjustable. It is possible that in the centre an air supply unit is intended within the drying device, which serves for a sufficiently great volume flow of air in the direction of the substrate. The air supply unit can comprise a supply channel, through which the air flows in the direction of the substrate. This supply channel can be opened, closed and/or partly opened by one or multiple flaps. The suction unit can comprise one or multiple suction channels, through which the air can be sucked, which is enriched with solvent. For example it is possible that in the centre a supply channel is intended in the drying device, wherein two suction channels are intended in the drying device between which the supply channel proceeds. 
     Likewise the invention involves that the distance between the substrate and the drying device is adjustable, which can be determined via said operating parameters. 
     Said object is further solved by a system with all features of the independent claim  5 . In the dependent system related claims possible embodiments are described. 
     According to the invention a system with a drying device is proposed for drying between inking units of a printing machine, by which a substrate is transportable via a rotating cylinder and is printable with colouring agents, wherein a printing image can be applied to the substrate by the colouring agents. The system comprises an air supply unit for supplying air in the direction of the substrate in order to effect a drying of the colouring agent. Further, the system comprises a suction unit for suctioning of air and a measuring unit, with which at least a part of operating parameters can be determined during the operation of the printing machine and/or the drying device. According to the invention a control unit is intended, which controls and/or regulates the air supply unit and/or the suction unit in dependence of the operation parameters in a way that the altering drying areas are adjustable at the substrate. It is particularly an advantage that an optimized drying of the colouring agent is achievable between the inking units, wherein at the same time the energy consumption of the system can be reduced since the drying device can be controlled and/or regulated individually for each inking unit, wherein the operating parameters determine the drying capacity according to each inking unit. The advantages of the previously described drying device are at this point likewise applicable within the scope of the system according to the invention. 
     Advantageously, the measuring unit can comprise an optical sensor, whose measuring range is directed to the substrate and/or at least a cylinder, wherein particularly the optical sensor is a camera unit and/or a sensor for the acquisition of the gloss level of the applied colouring agent. One or multiple operating parameters are measurable or can be determined by the optical sensor, wherein between the inking units the drying area and/or the drying areas are adjustable. The optical sensor can for example be a line scan camera. The optical sensor can using information about the printing image on the substrate, determine the size of the printed area of the substrate. Further, it is likewise possible that the printing degree of the printing image can be determined by the optical sensor, wherein the printing degree is determined over the density of the existing pattern points on the printing image. Hereby, it is possible that the printing image comprises a rough or a precise pattern, wherein the colour of the printing image is adjustable. The definition of the printing degree is for example comparable with the pixel resolution of a monitor. The optical sensor can be directed directly to the substrate in order to receive direct information according to the printing image wherein these information serves as an operating parameter for the adjustment of the drying area. Likewise it can be intended that the optical sensor is directed to one of the cylinders, for example a format cylinder and/or an anilox roller of the printing machine so that also with this embodiment information according to the printing image is deducible at the substrate, which in turn serves as operating parameters for the control unit in order to individually adjust drying zones at the substrate. 
     Likewise it is possible that at least one paint container is assigned to the printing machine in which the colouring agent can be inserted, wherein the paint container comprises an identification unit, from which a colour formulation code can be read out, which serves as an operating parameter for the control unit, particularly that the identification unit comprises a RFID chip, in which the colour formulation code is saved. Alternatively and/or additionally the identification unit can be intended for the substrate, which is particularly assembled at a carrier of the substrate or which is assembled in or at the substrate, wherein a substrate code can be read out from the identification unit. Beneath the colour formulation likewise the substrate as such can be a great influence factor for the adjustment of the drying capacity. The colour formulation code and the substrate code can be automatically read out during the operation of the printing machine and can be transferred to the drying device according to the invention, which subsequently carries out an automatic adjustment of the drying capacity. 
     Advantageously, the measuring unit can be assembled in the suction unit whereby the to be sucked air from the substrate can be analysed. The measuring unit can measure the air according to the solvent, wherein subsequently it can be indicative for the colour formulation, which is an operating parameter for the control unit. For example it is possible that a gas chromatograph determines the solvent contained in the air. 
     According to the invention it is intended that the printing machine comprises multiple inking units, wherein a drying device is assigned to each inking unit. Each drying device can be configured from different modules, which each for itself can in turn comprise an air supply unit and a suction unit. Therewith the printing machine can be configured with a drying system with a plurality of drying devices, which each configure the drying process of the substrate applied to the colouring agent between two inking units. 
     It can be further advantageous to integrate a heat exchanger within the system, which provides resulting waste heat of the printing machine to the drying device. This waste heat can be provided for the air supply unit, from which a defined volume flow with a corresponding temperature is produced, which flows in the direction of the substrate for the drying process. 
     A further advantage of the invention results when a heat exchanger is intended, which provides resulting waste heat to the printing machine of the drying device, particularly the air supply unit. By a corresponding increase of the temperature an increase of the heat supply into the air occurs, which is blown in the direction of the substrate through the air supply unit, wherein the drying is accelerated. By the use of a heat exchanger the energy input of the system according to the invention can be further optimized. 
     The previously mentioned object is further solved by a method for the operation of a drying device according to all features of the independent claim  12 . Hereby, a method is intended for the drying between inking units of the printing machine, by which a substrate is transported via rotating cylinders and is printed with colouring agents. According to the invention the drying device comprises an air supply unit for supplying air towards the substrate in order to effect a drying of the colouring agent. Further, the drying device comprises a suction unit for suctioning of the air and a measuring unit, with which at least a part of the operating parameters is determined during the operation of the printing machine. Further, according to the invention, a control unit is intended, which controls and/or regulates the air supply unit in dependence of the operating parameters in a way that altering drying areas are adjustable at the substrate. It is particularly advantageous that each drying device, which is assembled between two inking units, creates a drying area at the substrate in order to selectively achieve a drying of the printing image or the colouring agent on the substrate, wherein solvents evaporate during the drying process and are removed by the suction unit. Hereby, the energy input for operating the drying device can be selectively kept minimal since in dependence of the operating parameters the control unit can control the drying capacity. This means further that each drying device can be operated with different drying capacities since each inking unit uses different colouring agents and different printing images, different sizes of the printing images, different layer thicknesses during the colouring agent application and/or creates different printing degrees, which are considered via operating parameters in order to be able to adjust optimal drying areas at the substrate between each inking unit. Likewise here the advantages apply, which are already described for the system according to the invention or for the drying device according to the invention. 
     Advantageously the drying device can be controlled in dependence of the colouring agent supplied on the substrate, particularly the air supply unit and/or the suction unit can be controlled. Advantageously, the measuring unit can determine for example the thickness of the colour application of colouring agent and/or the printed area of the colouring agent and/or the printing degree, which influence the operating parameters in order to adjust the drying area at the substrate and finally determine the drying capacity of the drying device between each inking unit. 
     Likewise it is possible that at least a part of the operating parameters is transferred via an interface of the drying device and/or the printing machine. For example it is possible that the colour formulation code and/or the substrate code or data about the printing motive as operating parameters are read in via so called interface of the drying devices and/or the printing machine. The printing motive, which is for example assembled at the format cylinder particularly at the cliché of the format cylinder, can be evaluated in form of an image data, which have influence on the operating parameter in order to adjust individual drying areas at the substrate. The mentioned image data can already be available in digital form and can be transferred via the interface of the drying device and/or the printing machine. 
     Alternatively it is possible that the measuring unit determines the printing motive at the format cylinder and/or at the cliché of the format cylinder and out of this generates digital data, which is used as operating parameters for the control of the drying device. 
     Advantageously the operating parameters can be at least one of the following parameters:
         place and size of the colouring agent application at the substrate and/or at the cylinder;   drying speed of the colouring agent;   layer thickness of the colour application at the substrate;   printing degree;   colour formulation of the colouring agent and/or material of the substrate;   gloss degree of the colour agent application at the cylinder and/or at the substrate;   solvent amount in the air of the suction unit;   transport speed of the substrate;   temperature of the air in the suction unit and/or the air supply unit.       

     Said operating parameters can be determined or measured for example directly via the measuring unit according to the invention during the operation of the printing machine. Likewise the possibility occurs that via the measurement of defined parameters a part of said operating parameters can be calculated or determined via data bases, which are saved in the system according to the invention with the help of measuring units. The control unit can control and/or regulate the air supply unit and the suction unit via the operating parameters, this means that among others the volume flow of the air, which is responsible for the drying process, is adjusted accordingly wherein at the same time the air tempering regulation can be included in order to achieve a satisfying drying of the colouring agent. In case the drying capacity however is not sufficient in order to dry a given printing image with the adjusted transport speed of the substrate, the control unit can be configured in a way that the transport speed is reduced to a defined speed by which the printing image is just dried before it reaches the next inking unit particularly. 
     Further, the method according to the invention can be configured in a way that the drying device is operated in a circulating air procedure or in a circulation air procedure with a connectable fresh air procedure. Advantageously it has been shown that satisfying drying results can be achieved by air temperatures between 60° and 90°, wherein these do not lead to damages at the substrate material. Hereby, it has to be respected that different substrate materials are used, like for example paper, film from plastic, etc. in dependence of the substrate material, which as an operating parameter influences the calculation of the drying capacity, beneath the adjustment of the volume flow a corresponding temperature regulation can occur for the respective drying area. 
     Further, it can be an advantage that at the substrate and/or at the format cylinder and/or at an anilox roller of the inking unit of the printing machine the position and size of the colour agent application and/or the gloss degree and/or the drying speed can be determined, wherein particularly the position and the size of the colour application and/or the drying device is determined via the reflection of light at the surface of the format cylinder and/or the anilox roller. The degree of gloss can for example be measured by an optical sensor. For example the optical sensor can determine the degree of gloss by a reflection of light at the colouring agent surface of the anilox roller and/or at the format cylinder. This means that the areas of the anilox roller, by which no colour is applied to the format cylinder, comprise a different degree of gloss as the areas, by which a colour transfer to the format cylinder occurs. Therewith, the position and the size of the colour agent application to the substrate or the printing image can be implied. Likewise it is possible that an estimation of the drying speed can occur by measuring of the reflection of light at the colouring agent surface of the anilox roller and/or at the format cylinder wherein for example identification numbers or identification lines are already stored in a kind of data base within the system according to the invention. Via measuring points, which are a function of the reflection of light at the colouring agent surface and the time, the therefore assigned drying speed can be concluded. The drying speed in turn represents an operating parameter, which determines the drying capacity of the drying device, which means that within the drying speed of the drying device the volume flow, the temperature of the air is accordingly adjusted, which leaves the air supply unit in the direction of the substrate and is in turn discharged by the suction unit. 
     According to the invention the drying device can be used in a simple circulating air procedure. Likewise it is possible that the drying device is used in a circulating air procedure with a shiftable fresh air procedure. Hereby, it has to be considered that in a pure circulating air procedure the air can be continuously enriched with solvent during the drying, wherein with an increased percentage of solvent in the air the removal of the solvent from the colouring agent decreases wherein the actual drying speed of the substrate is reduced. Therewith, it can be meaningful to add a defined proportion of fresh air in order to decrease the concentration of the solvent in the circulating air. It can be a disadvantage that according to the temperature of the fresh air the circulating air is in turn heated up in order to achieve the desired drying capacity at the substrate. Advantageously, the drying device comprises a temperature sensor and a measuring unit, which can determine the percentage of solvent in the air. 
     Likewise it is possible that for the calculation of the necessary drying capacity of the single drying devices different methods are used, which can be summarized to a set value concerning the to be achieved drying capacities from different methods. Hereby, measurement errors can be reduced in the single methods. If for example the printed area and/or the printing degree can be measured with the sensor and also from an image data the method according to the invention, particularly the intelligent control unit for controlling and regulation of the single drying devices, can use the weighted means of the measured and determined values according to the printed area and/or the printing degree. For example the value of the printed area can be summarized to a determined value of approximately 60% from a measured value and approximately 40% from the image data. 
     According to the invention the area of the substrate, which is dried by the drying device can be limited to the area of the drying, which is printed in the previous inking unit or the previous inking units. If for example in the previous inking unit or previously inking units only the right and the left edge of the substrate is printed, the air supply unit of the subsequent drying device can only be active at the right and left edge. According to the complexity of the printing image it can also be an advantage that during the passing of the printing image at the drying device to open or close the nozzles or flaps in order to selectively direct an air flow to the areas of the substrate, which are equipped with the printing image. A measuring unit can be therefore intended, which previously determines and informs the control unit about the size and the position of the printing image at the substrate. 
     According to the invention image data of the cliché of the format cylinder can serve as operating parameters, particularly in order to determine the position and the size particularly the printing image at the substrate, which occurred by a colouring agent application. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Further advantages, features and details of the invention result from the subsequent description, in which possible embodiments of the invention are described in detail in relation to the drawings. Thereby the features mentioned in the claims and the description can be essential for the invention each single for themselves or in any combination. It is shown: 
         FIG. 1.1  a schematic drawing of the system according to the invention with the printing machine, which is configured with the printing unit between the inking units, 
         FIG. 1.2  a further alternative of the system shown in  FIG. 1.1 , 
         FIG. 1.3  a further embodiment of the system according to the invention according to  FIG. 1.1 , 
         FIG. 2  a schematic drawing of the drying device, which is assembled behind a printing unit of a printing machine, 
         FIG. 3  a schematic drawing of a drying device, which is configured with an air supply unit and a suction unit, 
         FIG. 4  a further drawing of a drying device according to the invention with an air supply unit and a suction unit, 
         FIG. 5  a further embodiment of the system according to the invention with a drying device and a measuring unit, which is assigned to the anilox roller, 
         FIG. 6  a diagram from which the estimation of the drying speed can be evaluated, 
         FIG. 7  a further schematic drawing of a system according to the invention with a drying device, which is in data communication with a control unit and a measuring unit, 
         FIG. 8  a further view of a drying device shown in  FIG. 7  and 
         FIG. 9  a schematic drawing of a method according to the invention for the determination of an optimal drying capacity, which is assigned to each inking unit. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
     In  FIGS. 1.1 to 1.3  a printing machine  1  according to the invention is shown respectively, which is configured from a plurality of inking units  7 . In the shown figures five inking units  7 . 1  to  7 . 5  are shown exemplarily, wherein the amount of inking units  7  can vary, which does not affect the substantial matter of the invention. 
     Between the inking units  7  a drying device  10  according to the invention is assembled respectively. The printing machine  1  transports a substrate  2 , which can for example be a paper material, a paper sheet or a plastic film, etc., via rotating cylinders  3 . 1 ,  3 . 2 ,  3 . 3 , wherein the inking units  7  apply a printing image on the surface of the substrate  2 . Hereby, a colouring agent  4  is applied to the surface of the substrate  2  via rotating cylinders  3 . 1 ,  3 . 2 ,  3 . 3 . In the shown embodiments each inking unit  7  is composed of an anilox roller  3 . 1  and a format cylinder  3 . 2 , wherein the anilox roller  3 . 1  comprises the colouring agent  4  from the paint container  31 . The printing machine  1  can however comprise further constructive embodiments concerning the type of rotating cylinder, the amount of cylinder, etc. The substantial matter of all embodiments according to the invention is however, that a drying device  10  according to the invention is assembled between the inking units  7 , which is in dependence of the operating parameters controlled in a way that the altering drying areas  13  like they are shown for example in  FIG. 8  are adjusted at the substrate  2 , which is subsequently described in detail. 
     Like it is explicitly shown in  FIG. 2 ,  FIG. 3 ,  FIG. 7  and  FIG. 8  the drying device  10  comprises an air supply unit  11  and a suction unit  12 , which are integrated in an assembly unit in the present embodiment. The air supply unit  11  effects a supply of air  5  in the direction of the substrate  2  in order to achieve a selective drying of the inking unit  4  on the substrate  2 . The air supply unit  11  comprises a supply channel  15 , which proceeds in the centre towards the suction unit  12 , which is responsible to discharge air  5 . The air supply unit  11  comprises a supply channel  15  and the suction unit  12  in turn is configured with two spaced apart suction channels  16 , wherein the supply channel  15  proceeds between the suction channels  16 . During drying an evaporation arises of the solvents contained in the printing image. The air  5  is enriched with solvents, which are removed by the suction unit  12 . A special feature of the invention is that the drying device  10  comprises a control unit  20 , which in dependence of operating parameter B controls and/or regulates the air supply unit  11  and/or the suction unit  12  in a way that concerning the applied printing image corresponding drying areas  13  are established according to each inking unit  7  in order to achieve an optimized and selective drying at the substrate  2  between the respective inking units  7 . Hereby, the energy requirement is significantly reduced during the operation of the printing machine  1  particularly because blank areas at the substrate  2  receive no or little drying by the drying device  10 . 
     In order to however effect an optimal drying between the inking units  7  a plurality of operating parameters B has to be taken into account, which are necessary for the determination of the optimal drying capacity L, which is subsequently described. 
     According to  FIG. 2 ,  FIG. 4  and  FIG. 8  the air supply unit  11  and the suction unit  12  is oriented transversely to the transport direction of the substrate  2 . In the present embodiment the drying device  10 , which is assembled from an air supply  11  and a suction unit  12 , is configured rod-like. The width of the transport device  10  can be greater than the width of the substrate  2 , which is shown in detail in  FIG. 2 . 
     According to  FIG. 4  it can be recognized that the air supply unit  11  comprises movable flaps  14 , wherein different drying areas  13  are adjustable via the respective position of the flaps  14 . Like it is schematically shown in  FIG. 4  the drying device  10  comprises multiple modules  30 . 1 ,  30 . 2 ,  30 . 3 , which each comprise an air supply unit  11  and a suction unit  12 . The modules  30 . 1 ,  30 . 2 ,  30 . 3  can be individually controllable so that the volume flow and/or the temperature and/or the flow direction of the discharging air  5  is adjustable in the direction of the substrate  2  of each module  30 . 1 ,  30 . 2 ,  30 . 3 . 
     The flaps  14  can be assembled on the side of the drying device  10  facing the substrate  2  alternatively and/or additionally the flaps  14  can be assembled on the side of the drying device  10  facing away from the substrate  2 . If the flaps  14  of a module  30  are in their closed position no discharging air occurs from the module  30 . Via this flap control an efficient inking unit drying can be performed selectively over the width of the substrate  2  (see  FIG. 8 ). Using operating parameters B the control unit  20  of the drying device  10  determines the drying capacity L of the drying device  10 , which is shown schematically in  FIG. 9 . In order to perform an efficient drying between the inking units  7  it is initially required to provide the necessary operating parameters B, which are visualized in the reference sign  60 . The following operating parameters B influence the drying or the adjustment of the drying capacity of the drying device  10 :
         position and size of the colouring agent application at the substrate  2  and/or at the cylinder;   drying speed of the colouring agent  4 ;   layer thickness of the colour application at the substrate  2 ;   printing degree,   colour formulation of the colouring agent  4  and/or material of the substrate  2 ;   degree of gloss of the colouring agent application at the cylinder  3 . 1  and/or at the substrate  2 ;   solvent amount of the air  5  in the suction unit  12 ;   transport speed of the substrate  2 ;   temperature of the air  5  in the suction unit  12  and/or in the air supply unit  11 .       

     For example it is possible that a part of said operating parameters B are determined via a measurement according to the reference sign  50  ( FIG. 9 ). Therefore a measuring unit  40  can be intended, which is for example configured with an optical sensor  41 . The measuring unit  40  is according to  FIG. 1.1  directed to the substrate  2  between the two inking units  7  respectively. The measuring unit  40  can determine the position and the size of the colour agent application at the substrate  2 , which is shown schematically in  FIG. 7 . Subsequently this information is transferred to the control unit  20 , which thereupon adjusts the drying device  10  according to the drying capacity L. At the same time it is possible that in dependence from other parameters the temperature of the air  5  flowing in the direction of the substrate  2  is adjusted and/or regulated within the drying device  10 . According to  FIG. 8  it is schematically shown that the system according to the invention is configured with a heat exchanger  35 , which provides the resulting heat waste of the drying device  10  or the air supply unit  11  in the printing machine  1 . 
     Alternatively the measuring unit  40  can optically review the surface of the format cylinder  3 . 2  and/or the surface of the anilox roller  3 . 1 , which is shown in  FIG. 1.2 or 1.3 . Via the recognized image data conclusions to the position and size of the printing image can be drawn between the inking units  7  so that the control unit  20  performs a corresponding control and regulation of the drying device  10 . 
     In a further embodiment according to  FIG. 6  it is possible to determine the drying speed of the colouring agent  4  using a measurement of reflection of light at the colour surface of the anilox roller  3 . 1  and/or the format cylinder  3 . 2 . The measuring unit  40  according to  FIG. 1.2  or  FIG. 1.3  determines the reflection of light wherein different drying speeds can be estimated by the control unit  20  using already existing measurement curves. In  FIG. 6  three measuring points lying mainly on top of each other are shown exemplarily. The upper measuring point is on a drying function, which is associated with a slow drying speed. The middle drying function constitutes a normal drying speed. The lower drying function constitutes a high drying speed. Since the operating parameter of the drying speed is likewise a significant size for the influence of the adjusting drying capacity of the drying device  10  it can be meaningful to involve operating parameters according to the invention with a selective energy supply for the drying process. 
     Via the measuring unit  40  further the printing degree, the gloss degree and/or the layer thickness of the colour application of the colouring agent  4  at the substrate  2  can be determined, which can be essential operating parameters B for the determination of the drying capacity L like just described. Likewise a solvent amount of the air  5  can be determined in the suction unit  12  via the measuring unit  40 , wherein for example the drying speed and/or the necessary drying capacity L of the drying device  10  can be determined. 
     Concerning  FIG. 9  it is likewise possible that the operating parameters B at least partially are already available at the system according to the invention (see reference sign  51 ). For example it is possible that each paint container  31  of each inking unit  7  comprises an identification unit  32 , which can be read out from a colour formulation code, which serves as an operating parameter B for the control unit  20 . Hereby, the identification unit  32  can comprise a RFID chip, in which the colour formulation code is saved. Via the colour formulation code a corresponding consideration concerning the drying capacity L can occur. Likewise for the substrate  2  an identification unit can be intended in the system according to the invention, like for example at a carrier of the substrate  2  particularly at its wrap. The identification unit can further be assembled directly in or at the substrate  2 , wherein a substrate code can be read out from the identification unit, which a control unit  20  comprises for the consideration of the drying capacity L. 
     According to  FIG. 1.2  it is possible that the measuring unit  40 , which is assigned to the format cylinder  3 . 2  is movable and/or rotatable so that at another position the measuring unit  40  can also be directed to the substrate  2  and therewith to the printing image or can adapt a position, which can be optically analysed and/or monitored in the anilox roller  3 . 2 . 
     The colour formulation code can be read out via the identification unit  32  and can be transferred to the control unit  20 . 
     The acquisition of the necessary operating parameters (reference sign  60 ) can therewith occur according to the described methods  50 ,  51 ,  52  from  FIG. 9 . The input of operating parameters (reference sign  52 ) can for example occur by a not explicitly shown interface by the operator of the printing machine  1 . Subsequently an optimal adjustment of the respective drying device  10  occurs by the control unit  20  in order to selectively and in an energy optimized manner dry the substrate  2  via the altering drying areas  13 . 
     In  FIG. 5  mainly the embodiment according to  FIG. 1.3  is shown, by which the drying device  10  is directed to a substrate  2  and at the same time the measuring unit  40  analyses the surface of the anilox roller  3 . 1 , like already described. The optical verification of the surface of the anilox roller  3 . 1  can occur via a reflection sensor, gloss sensor or via a camera unit, particularly a line scan camera. 
     Like it is schematically shown in  FIG. 9  for each drying device  10  an individual determination of the drying capacity L occurs so that between the inking units  7  different drying areas  13  occur. This means that within the drying device  10  in dependence from the moving substrate  2  the drying areas  13  can vary according to  FIG. 8 , this means that the amount of the drying areas can increase or can decrease or the size of the drying areas can vary likewise. This is dependent from the previously mentioned operating parameters particularly from the position and size of the colouring agent application, the layer thickness of the colour application, the printing degree, the colour formulation of the colouring agent  4 , the material of the substrate  2 , the solvent amount of the colouring agent  4 , the transport speed of the substrate  2  etc. 
     According to the determined size of the drying capacity L, which has to be adjusted for each drying device  10 , it can be necessary to additionally adjust the temperature of the air  5  in the air supply unit  11  and/or also to accordingly adjust the transport speed of the substrate  2 . 
     In a not explicitly shown embodiment it can be likewise intended that the control unit  20  is assembled central in and/or at the printing machine or in a drying device  10 , which determines the necessary drying capacity L for all drying devices  10 . Likewise it is possible that the measuring unit  40  and the drying device  10  are integrated in a common component. 
     REFERENCE SIGN 
     
         
           1  Printing machine 
           2  Substrate 
           3 . 1  Cylinder, anilox roller 
           3 . 2  Format cylinder 
           3 . 3  Pressure cylinder 
           4  Colouring agent 
           5  Air 
           7  Inking unit 
           7 . 1  Inking unit 
           7 . 2  Inking unit 
           7 . 3  Inking unit 
           7 . 4  Inking unit 
           7 . 5  Inking unit 
           10  Drying device 
           11  Air supply unit 
           12  Suction unit 
           13 . 1  Drying area 
           13 . 2  Drying area 
           13 . 3  Drying area 
           14  Flap 
           15  Supply channel 
           17  Suction channel 
           20  Control unit 
           30 . 1  Module 
           30 . 2  Module 
           30 . 3  Module 
           31  Paint container 
           32  Identification unit 
           35  Heat exchanger 
           40  Measuring unit 
           41  Optical sensor, camera 
           50  Measurement of operating parameters 
           51  Presence of operating parameters 
           52  Input of operating parameters 
           60  Acquisition of operating parameters 
           70  Determination of the drying capacity L 
         B Operating parameter 
         L Drying capacity