Method for maximizing the printing speed and minimizing the power consumption of a printing machine

Abstract

Disclosed is a method for controlling all the printing units of a press given the performance of each of its dryers. In particular, the system computes the maximum speed at which it can produce given the ink and paper characteristics and the print coverage of each color separation and chooses a printing speed compatible with each dryer given what each dryer has to dry. In practice, this is about printing at the maximum speed of the slowest dryer. Once the print speed is set each dryer is optimized to use less power, by reducing the speed of the fan in the dryers and by recirculating as much air as possible in in the dryer while keeping the solvent concentration at a safe level.

Description

FIELD OF THE INVENTION

[0001] The present invention pertains to a method for configuring a printing machine's settings with the aim of minimizing its power consumption. This method applies particularly to rotary in-line printing machines, where each printing or coating unit is succeeded by a drying unit responsible for drying the ink before the next printing unit applies fresh ink. Additionally, the invention is applicable to a coating machine, where the coating material is effectively "printed" onto a substrate using a coating unit. It's worth noting that we will employ the same vocabulary and treat the coating machine as if it were "printing" the coating material. In this context, a coating unit is managed similarly to a printing unit, albeit with distinct parameter values and operational guidelines.TECHNICAL BACKGROUND

[0002] The power consumption of a printing (or coating) machine is mainly affected by the printing speed and the ventilation power of the drying unit. The power consumption tends to be reduced at high speed, while the maximum printing speed tends to be limited by the maximum drying capacity of the drying unit. The printing speed is limited mainly by the drying unit capacity given the substrate type, ink and print coverage.

[0003] The essential measure of drying unit capacity is its ability to evaporate solvent within a specific timeframe. This capacity is influenced by various factors, including the solvent type, ink or coating material type, substrate type, and its thickness. Furthermore, it hinges on the drying unit's airflow, which is determined by the drying unit fan(s). The quantity of solvent that must be evaporated per unit of surface area is determined by both the ink's grammage and its dry percentage. Consequently, when considering the surface area, the amount of solvent to be evaporated is contingent upon the substrate's width, printing speed, and print coverage, in addition to the grammage and dry percentage of the ink.SUMMARY OF THE INVENTION

[0004] To determine the maximum printing speed of a complete printing or coating machine, we need to determine the maximum speed of each printing unit and choose the speed according to the slowest printing unit. The maximum printing speed may differ between units due to varying print jobs, due to the presence of a coating unit, due to varying ink amounts for different pattern colors (each unit prints a single color), and due to some units having a drying unit with a larger capacity for faster drying. Typically, some printing machines have a stronger drying unit in the last printing unit to print a white background with full ink coverage.

[0005] It is an object of the invention to provide a method that controls a printing or coating machine. The machine has several printing or coating units, each having a drying unit with a controllable fan and an air recirculation circuit. The method comprises the following steps: a) Selecting a set of global printing or coating parameters of the printing or coating unit. The set of parameters includes: a type, width, and thickness of a substrate to be printed, a type of ink or coating material, a type of solvent, a grammage, and dry percentage b) Computing, for each printing unit, a maximum printing speed according to a maximum drying capacity of its drying unit, the global printing parameters, and the print coverage of the color separation assigned to said printing unit - called the unit-specific print coverage, c) Setting a global printing speed as the speed of the slowest printing unit. In other words, setting the global printing speed as the minimum value of said printing speed maxima, and adding it to the global printing parameters, d) Then, for each printing unit, computing a unit-specific drying parameters comprising the fan speed, the temperature of the drying unit, and optionally the air recirculation rate, according to (1) a global printing parameters, (2) and a print coverage of the color separation assigned to said unit, by using a predetermined formula and / or a lookup table. For example, if the printing unit does not have much solvent to evaporate, we can afford to drive the dryer fan at a low speed, thus gaining power consumption, e) And afterwards processing the substrate with the printing or coating unit according to said global printing parameters and unit-specific drying parameters.

[0006] By solvent we mean the solvent used for the ink or coating material. The grammage is the grammage of the ink or coating material per unit surface on the substrate. The dry percentage is the dry percentage of the ink or coating material.

[0007] While the air recirculation rate has less direct influence on drying capacity compared to fan speed or temperature, it plays a critical role in ensuring safety (by reducing explosion risk) and supporting sustainability. Thus, after the global printing parameters of the printer have been selected and before the substrate has been processed, the maximum speed for each printing unit is calculated. Based on the calculation result, the global printing speed of multiple printing units is set. Based on the global printing speed, the corresponding fan speed, optionally the air recirculation rate, and the temperature of the drying unit are calculated for each drying unit by a formula and are set based on the results of a formula. The formula calculated, for example, the amount of solvent to be removed from the substrate per unit of time is calculated, which depends on the type of solvent used. The unit-specific drying parameters are thus set in advance, before the substrate is processed by the printing or coating unit, and adjusted to the previously set global printing or coating parameters.

[0008] The maximum printing speed of each printing or coating unit is calculated based on the maximum drying capacity of the corresponding drying unit. In this way, the speed of the printing or coating units is adapted to the speed of the drying unit and an individually set of unit-specific drying parameters is computed for each printing or coating unit.

[0009] At least one parameter among the unit-specific drying parameters depends on the global printing parameters and / or on the unit-specific print coverage. Thus, the unit-specific drying parameter is a parameter of the drying unit.

[0010] The invention also addresses a method to compute or improve said predetermined formula or lookup table and it is defined in the claims section of this disclosure.BRIEF DESCRIPTION OF THE FIGURES

[0011] Embodiments of the present invention are illustrated by way of example in the accompanying drawings in which reference numbers indicate the same or similar elements and in which: Figure 1 shows an example of a printing or coating machine connected to a remote computer, where the winder, the unwinder and the elements for controlling the substrate speed and tension are illustrated, Figure 2 shows an example of a printing machine with several printing units, where the method according to the invention can be applied, Figure 3 shows an example of a printing or coating unit with its drying unit, according to the invention, Figure 4 shows a method for computing the printing speed of the printing or coating machine, Figure 5 shows a method for setting the unit-specific drying parameters in each printing or coating unit, Figure 6 shows the overall method for setting the printing or coating machine parameters, Figure 7 shows an example of possible printing speeds for a given ink and substrate in relation to the drying temperature. DETAILED DESCRIPTION OF THE INVENTION AND OF SOME OF ITS EMBODIMENTS

[0012] A printing machine 1 comprises several printing units 2. The printing machine 1 could also be a coating machine 1 with one or several coating units 2. The method disclosed here for a printing machine may also be applied to a coating machine. A substrate 4 runs from one printing or coating unit 2 to the next. Each printing or coating unit 2 is associated with a drying unit 6 located downstream from the printing or coating unit 2 when following the path of the substrate 4. The printing speed 8 is the same for all the printing or coating units 2.

[0013] To minimize the power consumption of the printing machine 1 we compute the maximum printing speed 108 of each printing or coating unit 2. The printing speed is limited by the drying unit 6 capacity.Setting the unit-specific drying parameters given the printing speed

[0014] The drying unit 6 has an internal air recirculation circuit 10 powered by a controllable fan 12. The air is circulated in the circuit 10 by being pushed by the fan 12 and heated by a heater 14. The temperature 15 is measured in the circuit by a thermometer. The air flows toward the substrate 4 and causes an evaporation of the solvent, which is mixed with ink on the substrate. The air and solvent mixture 18 then reach a damper 22 that recirculates a proportion of the air and solvent mixture 18, removes some of the mixture 18 from the circuit 10, and replaces the missing mixture with fresh air from outside. The proportion of solvent in the mixture is measured by a sensor 20, which is preferably located on the circuit 10, between the substrate 4 and the damper 22. The speed 13 of the fan 12 can be set by the machine's control unit 9. Its maximum speed defines the maximum drying capacity of the drying unit 6. The temperature 15 must be kept within a range: it must be hot enough to have a good drying capacity, and cold enough to prevent an explosion. The damper 22 determines the proportion of air that loops in the air recirculation circuit 10, and the proportion that gets replaced by fresh air. Thus, by setting the damper 22 position, we set the air recirculation rate 23. Some of the air must be replaced by fresh air to avoid saturating the air in the circuit with solvent. The maximum amount of solvent allowed is given by the safety specification of the setup. Too much solvent might cause an explosion but recycling the solvent (outside of the drying unit) is only doable if the solvent concentration is high enough. Also, fresh air must be heated before reaching the circuit, thus consuming more energy. Consequently, there is an optimal recirculation proportion to be set. This optimum is reached by setting the solvent concentration to its maximum allowable level. When referring to the 'maximum allowable level,' we are specifying a threshold that is assured not to exceed the limit defined by the safety specification. This consideration takes into account the natural variability in this value stemming from the inherent inaccuracies present in all components contributing to the setting (the damper, the sensor, and the reactivity of the system in time). The proposition of solvent in the air recirculation circuit 10 is measured by a sensor 20. The set of parameters comprising the temperature 15 measured by the sensor 20, and the fan speed 13 constitutes the core of the unit-specific drying parameters 40. Preferably, the air recirculation rate 23 may also be part of the core of the unit-specific drying parameters 40, because it is generally set with the fan speed and temperature, but it is particular in the sense that it does not directly impact the quality of the print. It impacts safety and sustainability.

[0015] To set the temperature, we can use the data in Figure 7. The temperature must be kept between two boundaries: it is lower bounded by an ink curve, and upper bounded by a substrate curve. Being above the ink curve ensures that the solvent (or water) is evaporated from the ink, and being under the substrate curve ensures that the substrate doesn't get damaged by an excessive temperature. Type A substrates are rigid substrates while type D substrates are extendable substrates. Type B and C are substrates whose properties lie in-between. Examples of inks and substrate types are given in Table 1: Table 1: categorization of inks and substratesSubstrate AAluminium, paperSubstrate BPETSubstrate CBOPP, BOPA, CPPSubstrate DPVC, PETG, OPS, PE, PVDCInk ANU-PC, NCInk BPVBInk CWater-based inks

[0016] Within the margin given by the two curves, one may decide for a high temperature to reduce the risk of not drying the print correctly, or for a low temperature to reduce the risk of deforming the substrate while saving some energy. Thus, the input temperature could be specified as which risk to emphasize, with a default value that lies in the middle of the two curves.

[0017] To set the fan speed 13, i.e. a unit-specific drying parameter, the method computes the amount of solvent to be removed from the substrate per unit of time. This amount is given by the amount of ink that crosses the drying unit multiplied by the percentage of solvent in the ink (i.e., one minus the dry percentage). The amount of ink is given by multiplying the grammage by the print coverage and the printing speed 8. Then, from the amount of solvent per unit of time, the unit-specific drying parameters 40 are set depending on the type of solvent used. These last parameters are given by the solvent manufacturers and / or determined on an empirical basis.

[0018] In practice, we can compute an empirical dryer capacity index K, which is equal to the percentage of solvent (or water) in the ink divided by the percentage of solid material in the ink multiplied by the grammage of the ink, i.e. the amount of ink per unit surface of the substrate. The result is then multiplied by the printing speed (i.e. the running speed of the substrate) divided by the dryer hood length: K is expressed in kg / (m 2< · hours) K_solv is a parameter which depends on the solvent. For a standard solvent, K_solv = 1. If the solvent is water, in other words, if we use water-based inks, we use K_solv = 3 to obtain K. K is an estimator of the drying goodness, the lower the value the better the drying. Let's call K_dry the value of K at which the print is well-dried. The parameter K_dry tends to depend on the press. On our machines K_dry = 36.

[0019] For a given printing unit, if the value ok K is smaller than K_dry, we may consider reducing the fan speed. For example we may set the fan speed, in percentage to its nominal speed with the formula: fan_speed = (K / K_dry)^0.33 *100 [%]. For example, if K is about half of K_dry, we set the fan speed to 80% of its nominal speed, and thereby gain 50% of the power consumption of the fan. We may lowerbound this percentage to avoid reaching a value close to 0 where this rough estimate would be too approximate (the formula of drying goodness using value K is a rough estimate of the real drying process). To compute the parameter K_dry for any presses, we need to know under which conditions the job can be printed and dried. These conditions are given for a particular combination of ink and substrate by the press manufacturer or can be measured using the first successfully printed job. We then compute parameter K under these conditions for the most critical drying unit, which results in the value K_dry. Equivalently, we may compute the K value for each drying unit and set K_dry as the maximum of these values.

[0020] Thus, once the printing speed 8 is given, the drying unit sets unit-specific drying parameters 40, i.e. the fan speed 13, the air recirculation rate 23, or the temperature 15 of the drying unit, to a value that depends on said printing speed 8 and minimizes the power consumption.

[0021] In practice, if the drying unit is new in a product line, or if the substrate or ink is not well known, the drying unit may be operated in only two modes: a FULL mode, with the fan speed set at its maximum value, and an ECO mode, where the fan speed is set to 80% of its maximum speed, which reduced its power consumption by half (there is a cubic relationship between fan speed and power consumption). ECO mode is selected in each printing unit where K / K_dry is smaller or equal to 50%. Simplifying to just FULL mode and ECO mode offers the benefit of ease and clarity, making it easier to pinpoint issues if the print drying deviates from specifications. Once enough data is collected about the drying unit and substrate and ink combination, the fan speed can be determined more in a more precise way, for example using the fan_speed formulaComputing the maximum substrate speed allowed by the drying unit

[0022] The maximum allowable printing speed 108 of a printing or coating unit 2 is limited by the maximum speed of the printing rollers and the maximum speed allowed by the drying unit, which is most of the time the limiting factor. To compute the maximum allowable printing speed 108 from the drying unit's perspective, the fan 12 of the drying unit 6 is set to its maximum (recommended) value, while the heater 14 and the damper 22 at set to a value to maximize the solvent evaporation while staying within the safety specification. Most of the time, this is achieved by opening the damper 22 to replace the air with fresh air and setting the heater 14 to reach the maximum allowable temperature. This gives the amount of solvent that can be removed from the substrate per unit of time. Since this amount is equal to the amount of ink that crosses the drying unit multiplied by the percentage of solvent in the ink, we can compute the maximum allowable printing speed 108. Alternatively, If the printer is already well-characterized, we can compute the maximum print speed (i.e. the maximum printing speed allowed by the dryer) by setting K / K_dry = 100% and solving for the printing speed.Fine-tuning the drying unit parametric model

[0023] To improve the efficiency of the unit-specific drying parameters 40, the drying unit 6 needs to precisely estimate the influence that each of the settable unit-specific drying parameters 40 has on the drying process. In this way, it can set the unit-specific drying parameters 40 to successfully run the drying process while minimizing power consumption. To improve the model that estimates the effect of each parameter on the drying process, i.e. Table 1, the fan_speed formula and figure 7, the machine is connected to a remote computer 7, and thanks to a feedback process, the precision of the model can be improved. The method works as follows: For a predefined drying unit model, an operator sets the unit-specific drying parameters 40 (including the fan speed 13, the air recirculation rate 23 and the temperature 15), with the aim of producing at maximum speed and / or consuming little power (i.e. trying to set the minimal fan speed 13, a low temperature 15 and a high air recirculation rate 23). Alternatively, the initial parameter set is proposed by the remote computer based on a predefined parametric model of the printer. The printer is running, and the operator checks the print quality and checks that the solvent concentration remains under the explosion safety limit. The operator "plays" with the parameters until the quality is good. Then, the operator accepts the settings, and the job is run.

[0024] When the settings are accepted, the printing machine records the unit-specific drying parameters 40, the printing parameters 30, and the make and model of the drying unit. It then measures the power consumption of the drying unit 6 and sends this complete set of parameters 30,40 to the remote computer 7. The remote computer creates an entry in a database 79 and builds a lookup table for each drying unit model. In other words, the remote computer builds a correspondence between the set of global printing parameters 30, unit-specific drying parameters 40, and power consumption. For example, we may compute a K_solv value for each ink-solvent combination and a K_dry value for each type of printing unit. If enough data is available, we may select all the print jobs with the same printing unit configuration, the same ink and the same solvent and interpolate or choose between the set of parameters that led to successful jobs.

[0025] The remote computer is preferably connected to several printing machines throughout the world. Thus, when a printing machine starts a new job, if it does not have the required data or knowledge to set up the printing and / or drying parameters 30, 40, the printer may send a request to the remote computer. The computation is a two-step process that runs in the remote computer: first, it determines the maximum printing speed 108 of every printing or coating unit 2, then chooses a compatible printing speed 8---which is preferably the maximum printing speed 108 of the slowest printing unit---and then, given that printing speed 8, it determines the unit-specific drying parameters 40 for every printing unit with the aim to minimize power consumption. Thus, the remote computer searches the database 79 for that printer / drying unit model and given, The type, width, and thickness of a substrate to be printed 32, The type of ink or type of coating material 34, The type of solvent 36, The print coverage, grammage, and dry percentage 38 (i.e., the global printing parameters 30 excluding the printing speed 8) and computes the maximum printing speed 108 for every printing unit.

[0026] Then it chooses a printing speed 8 compatible with every printing or coating unit 2, and adds it to the global printing parameters 30. Thus, from The type, width, and thickness of a substrate to be printed 32, The type of ink or type of coating material 34, The type of solvent 36, The print coverage, grammage, and dry percentage 38 The printing speed 8

[0027] The remote computer 7 computes the unit-specific drying parameters 40 for every printing or coating unit 2 that will consume the least possible energy. It then sends the unit-specific drying parameters 40 for each printing unit and the (global) printing speed 8 back to the printing machine 1.

[0028] In practice, once the remote computer 7 has collected enough data for a given drying unit model, it may build a parametric model to compute the drying parameters from the global printing parameters 30 including the printing speed 8 (shown in Figures 5 and 6) and another model that computes the maximum printing speed 108 given the global printing parameters 30 excluding the printing speed 8, shown in Figure 4. This model may be computed by interpolating between the set of global printing parameters 30 and unit-specific drying parameters 40, by statistical data fitting, or by machine learning techniques.

[0029] When data is missing, for example, if the substrate is now, the remote computer works by analogy: it finds the known material with the most similar properties and sets up the printer according to the parameters linked to said material. For example, if a new plastic substrate is used, then the remote computer finds another plastic in the list. If a new metal substrate is used, then the remote computer uses the parameters of another metal substrate in the list. Also, when setting the tension-related parameters for a new material, the remote computer will use the data of a substrate having a similar young modulus. These parameters are provided as initial parameters that will be corrected by the operator if the result does not produce a print according to specifications.

[0030] Over time, the printing machines may send information about the drying parameters, the printing or coating parameters, the make and model of the drying unit, and a quality tag whenever quality control is performed and validated. The quality tag specifies if the print was within- or out of- specifications. Please note that the printing machine may send this information even when the quality is deemed out of specification. This information, once collected over time improves the precision of the global printing parameter 30 and unit-specific drying parameter 40 set determination.

[0031] Preferably, the parametric model of the printer or drying unit is learnt based on an empirical model of the printer to which a correction is added. Thus, the system learns the difference to apply to the parameters set given a predetermined parametric model. The predetermined parametric model is based on empirical and historical knowledge of the printer.Setting up the printer parameters

[0032] Once the printing speed 8 is determined, the control unit 9 of the printing machine 1 sets some side parameters of the printer which control the substrate speed and tension and sets the parameters in each of the printer units.

[0033] The substrate is stored on a reel 50, and unwound by the unwinder 60. Then follows an unwinder draw group 62 that controls the tension of the substrate. The substrate is then processed by the set of printing units, goes through a rewinder draw group 72, which is also used to control the substrate tension and is finally rewound in a rewinder 70 to finish in the processed substrate reel 51. In practice, the unwinder tension 61 and speed 66, the unwinder group tension 63 and speed 68, the rewinder tension 71 and speed 76 and the rewinder group tension 73 and speed 78. These parameters may be added to the global printing parameters. Adding these parameters to the global printing parameters allows for a more complete model of the printer control, and thus allows the collection of a whole set of parameters that are producing prints according to specification.Setting up the printing unit

[0034] In each printing unit, the control system of the printer sets the unit Nip pressure 82, the Doctor Blade pressure 84, the doctor blade oscillating speed 86, the ink pump speed pressure 88, the ink roll speed 90 (according to the speed of the substrate) and the ink roll pressure 92. These parameters may be added to the global printing parameters. Adding these parameters to the global printing parameters allows for a more complete model of the printing unit control, and thus allows the collection of a whole set of parameters that are producing prints according to specification.

Claims

1. A method for controlling a printing or a coating machine (1) having several printing or coating units (2) each having a drying unit (6), each drying unit (6) comprising a controllable fan (12) and an air recirculation circuit (10), the method comprising f) Selecting a set of global printing parameters (30) of the printing or coating unit (2), defined as a set of printing parameters (30) comprising - a type, width, and thickness of a substrate (4) to be printed (32), - a type of ink or coating material (34), - a type of solvent (36) of the ink or coating material (34), - a grammage of the ink or coating material (34) on the substrate (4) to be printed (32), and dry percentage (38) of the ink or coating material (34); g) Computing, for each printing or coating unit (2), a maximum printing speed (108) according to a maximum drying capacity of its drying unit (6), the global printing parameters (30), and a print coverage of a color separation assigned to said printing or coating unit (2) - called the unit-specific print coverage; h) Setting a printing speed (8) as a minimum value of said printing speed maxima (108), and adding it to the global printing parameters (30); i) Then, for each printing or coating unit (2), computing a set of unit-specific drying parameters (40) comprising a fan speed (13) and a temperature (15) of the drying unit according to (1) the global printing parameters (30), (2) and the print coverage of the color separation assigned to said unit, by using a predetermined formula and / or a lookup table, j) And afterwards processing the substrate (4) with the printing or coating unit (2) according to said global printing parameters (30) and unit-specific drying parameters (40).

2. The method according to claim 1, wherein the fan speed (13) and the temperature (15) depend on the printing speed (8) and the print coverage of a color separation assigned to each printing or coating unit (2).

3. The method according to claim 2, wherein the air recirculation rate (23) depends on the printing speed (8) and the print coverage of a color separation assigned to each printing or coating unit (2).

4. The method according to claims 1, 2 or 3, for a printing or a coating machine (1) connected to a remote computer (7), wherein the printing or coating machine (1) collects global printing parameters (30), and sends a request to the remote computer (7) with said parameters, along with a printer and dryer model (39), the remote computer (7) computes for each printing unit (2), the unit-specific drying parameters (40) by using a predetermined formula and / or a lookup table, and sends said unit-specific drying parameters (40) back to the printing or coating machine (1), the printing or coating machine (1) processes the substrate (4) with the printing or coating unit (2) according to said global printing parameters (30) and unit-specific drying parameters (40).

5. The method according to claim 4, for a printing or a coating machine (1) connected to the remote computer (7), wherein a quality of the output of the printing or coating unit is inspected, and the quality of the print is evaluated and tagged with a tag as within specification or out of specification, resulting in a quality tag that is entered into a machine interface, and the machine collects the global printing parameters (30) along with the quality tag and the machine / dryer model (39) and sends a message to the remote computer (7).

6. The method according to claims 4 or 5, wherein the global printing parameters (30) further comprise an unwinder tension (61), an unwinder group tension (63), a rewinder tension (71) and a rewinder group tension (73) of an unwinder or a rewinder of the printing or coating machine (1).

7. A printing or a coating machine (1) comprising at least two printing or coating units (2) each having a drying unit (6), each drying unit (6) comprising a controllable fan (12) and an air recirculation circuit (10), a central control unit (9), connectable to a remote computer (7), wherein the central control unit (9) is configured to a) Select a set of global printing parameters (30) of the printing or coating unit, defined as a set of parameters comprising: - a type, width, and thickness of a substrate (4) to be printed (32), - a type of ink or coating material (34), - a type of solvent (36) of the ink or coating material (34), - a grammage of the ink or coating material (34) on the substrate (4) to be printed (32), and dry percentage (38) of the ink or coating material (34); b) Compute, for each printing unit, a maximum printing speed (108) according to a maximum drying capacity of its drying unit (6), the global printing parameters (30), and a print coverage of the color separation assigned to said printing unit - called a unit-specific print coverage; c) Setting a printing speed (8) as a minimum value of said printing speed maxima (108), and adding it to the global printing parameters (30); d) Then, for each printing unit, computing a set of unit-specific drying parameters (40) comprising a fan speed (13) and a temperature (15) of the drying unit according to (1) the global printing parameters (30), (2) and the print coverage of the color plane assigned to said unit, by using a predetermined formula and / or a lookup table. e) And processing the substrate (4) with the printing or coating unit (2) according to said global printing parameters (30) and unit-specific drying parameters (40).

8. The printing or a coating machine (1) according to claim 7, wherein the step (d) of computing the set of unit-specific drying parameters (4) comprises computing an air recirculation rate (23) as part of the unit-specific drying parameters (40).

9. The printing or a coating machine (1) according to claim 7 or 8, further comprising a connection (77) to a remote computer (7), wherein the central control unit (9) is configured to send the global printing parameters (30) of the printing or coating unit to the remote computer through said connection and receive in return the unit-specific drying parameters (40) for each printing unit

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