Device for printing a printing substrate and method for controlling a device

Abstract

A device (1) for printing on a printing substrate is provided. The device (1) comprises a printhead (2) for printing on a printing substrate with a printing medium, a first reservoir (3) for receiving the printing medium, a second reservoir (4) for receiving the printing medium, a first pressure setting unit (5), a second pressure setting unit (6), a first sensor (7), a second sensor (8), and a control unit. The first reservoir (3) is fluidically connected to an inlet of the printhead (2), and the second reservoir (4) is fluidically connected to an outlet (10) of the printhead (2), so that printing medium can flow from the first reservoir (3) through the printhead (2) into the second reservoir (4).The first sensor (7) is configured to detect a property of the printing medium as the printing medium flows from the first reservoir (3) to the printhead (2), and the second sensor (8) is configured to detect a property of the printing medium as the printing medium flows from the printhead (2) to the second reservoir (4). The first pressure setting unit (5) is configured to set a first pressure on or in the first reservoir (3), and the second pressure setting unit (6) is configured to set a second pressure on or in the second reservoir (4). The control unit is configured to control the first pressure setting unit (5) and / or the second pressure setting unit (6) based on the property detected by the first sensor (7) and / or the second sensor (8), preferably the property detected by the first sensor (7) and / or the second sensor (8) being the pressure of the printing medium.Furthermore, a method for controlling a device for printing on a printing substrate has been created.

Description

[0001] The invention relates to a device for printing on a printing substrate. The invention also relates to a method for controlling such a device. background

[0002] Inkjet printers are frequently used to print onto a substrate with a printing medium, such as ink. These printers can print on the substrate using either drop-on-demand or continuous jet printing. In drop-on-demand printing, individual droplets are selectively ejected from a printhead. For example, in a bubble jet process, a heating element generates a vapor bubble, the pressure of which forces the droplet out of the printhead nozzle. Alternatively, a piezoelectric element can generate pressure that forces a droplet out of the printhead nozzle.

[0003] To achieve good print quality, precise control of the ink flow rate to and through the printhead is essential. Furthermore, precise control of the ink meniscus pressure within the printhead, nozzle, or nozzle line can be desirable to prevent, for example, unwanted ink leakage from the printhead.

[0004] With known devices and methods, the flow rate, the pressure at the inlet and outlet of the printhead, and / or the meniscus pressure are often difficult to control and / or regulate. Frequently, the fill level in a tank fluidically connected to the printhead, from which the printing medium can be supplied to the printhead, is measured in order to determine a hydrostatic pressure based on the fill level, the height of the tank, and other factors. Such determination of the flow rate and pressures is comparatively difficult and inaccurate, since, on the one hand, inaccurate level sensors can lead to comparatively high measurement inaccuracies, and on the other hand, the pipe routing can also have an influence. Consequently, the control and / or regulation of the flow rate, the pressure at the inlet and outlet of the printhead, and / or the meniscus pressure is comparatively inaccurate.

[0005] Such a device and method are known from EP 2 875 956 A1. Pressure medium is supplied from a first tank to a printhead. Pressure medium not ejected through the printhead nozzle is fed from the printhead into a second tank. Level sensors measure the fill level of the respective tanks, and based on these measurements, a recirculation pump is activated to return pressure medium from the second tank to the first tank. The first and second tanks are arranged above the printhead. Pressure medium is drawn to the printhead by applying a vacuum. However, no properties of the pressure medium are measured, in particular no pressure measurement, when pressure medium flows from the tank to the printhead or from the printhead to the tank.

[0006] A device is known from EP 2 769 847 A2. In this device, a pressure sensor and a temperature sensor are provided in a supply line, through which the printing medium is supplied to a printhead, and a return line, through which the printing medium is discharged from the printhead. The sensors are combined in a flow-through sensor block. The printing medium is drawn from a tank by a circulation pump, passed through a heating element, heated, passed through the sensor block in front of the printhead, and supplied to the printhead. Printing medium not ejected through the printhead nozzle is drawn from the printhead through the sensor block and then back into the tank. The circulation pump is fluidically arranged between the tank and the heating element. The sensors serve to detect blockages, e.g., of a filter or a line. If overpressure occurs on the pressure side of the circulation pump, e.g.,Due to a clogged filter or other obstruction in one of the lines or the printhead, pressurized fluid is diverted back to the recirculating tank via a bypass line. In this case, the pressure measured by the sensors drops below a minimum threshold, triggering an alarm signal that is sent to a control system. The system is shut down until the overpressure event is resolved.

[0007] Even this well-known device cannot control and / or regulate the flow rate, the pressure at the inlet and outlet of the printhead, and / or the meniscus pressure accurately enough. Summary

[0008] It is therefore an object of the present invention to provide a device for printing on a printing substrate and a method for controlling such a device that overcome these disadvantages. The device and method according to the invention enable precise control and / or regulation of a delivery rate and / or flow rate to and / or through the printhead.

[0009] This problem is solved by a device having the features of claim 1, and a method having the features of claim 13. The dependent claims relate to advantageous embodiments.

[0010] According to one aspect, a device for printing on a substrate is provided, wherein the device comprises a printhead for printing on the substrate with a printing medium, a first container for receiving the printing medium, and a second container for receiving the printing medium. The first container is fluidically connected to an inlet of the printhead, and the second container is fluidically connected to an outlet of the printhead, such that printing medium can flow from the first container through the printhead into the second container. The device includes a first sensor and a second sensor, wherein the first sensor is configured to detect a property of the printing medium when printing medium flows from the first container to the printhead, and the second sensor is configured to detect a property of the printing medium when printing medium flows from the printhead to the second container.The device comprises a first pressure setting unit and a second pressure setting unit, the first pressure setting unit being configured to set a first pressure on or in the first container and the second pressure setting unit being configured to set a second pressure on or in the second container. The device comprises a control unit configured to control the first pressure setting unit and / or the second pressure setting unit based on the characteristic detected by the first sensor and / or the second sensor.

[0011] According to another aspect, a method for controlling a device for printing on a printing substrate is provided, comprising the steps of: detecting a property of a pressure medium flowing from a first container of the device to a printhead of the device with a first sensor; detecting a property of a pressure medium flowing from the printhead to a second container of the device with a second sensor; controlling, based on the properties of the pressure medium detected by the first and / or the second sensor, a first pressure setting unit of the device, wherein the first pressure setting unit sets a first pressure on or in the first container based on the properties detected by the first and / or the second sensor;and controls, based on the properties of the pressure medium detected by the first and / or the second sensor, a second pressure setting unit of the device, wherein the second pressure setting unit sets a second pressure on or in the second container based on the properties detected by the first and / or the second sensor.

[0012] Because the first pressure setting unit can set a first pressure in the first container, and the second pressure setting unit can set a second pressure in the second container, the flow rate of pressure medium to and / or through the printhead can be set, controlled, and / or regulated with high accuracy. The first pressure can be higher than the second pressure.

[0013] Since the first sensor can detect a property of the fluid flowing from the first container to the printhead, and the second sensor can detect a property of the fluid flowing from the printhead to the second container, the first and / or the second pressure setting unit can be controlled in such a way that a predetermined pressure can be achieved with high accuracy fluidically upstream and / or downstream of the printhead, and / or can be adjusted, controlled, and / or regulated accordingly with high accuracy. In some embodiments, the meniscus pressure of the printhead can be precisely set and / or controlled. The flow rate can be determined accordingly simply and easily from the properties detected by the first and second sensors, for example, based on the pressures of the printing medium measured by the sensors.

[0014] The first sensor can be located outside the first container and / or the second container. The second sensor can also be located outside the first container and / or the second container. This can result in higher measurement accuracy compared to sensors located inside the containers.

[0015] The device can be or include a printer. For example, the device can be or include an inkjet printer, e.g., a bubble jet printer and / or a piezo printer, and / or an inkjet printer. The printing medium can be liquid. The printing medium can be, for example, ink.

[0016] The property of the pressure medium detected by the first sensor can be a state variable of the pressure medium. The property of the pressure medium detected by the second sensor can also be a state variable of the pressure medium. The state variable and / or property can, for example, be or include temperature. The state variable and / or property can, for example, be or include pressure.

[0017] The first pressure setting unit can be controlled in such a way that the pressure set by the first pressure setting unit in the first container can be controlled. The second pressure setting unit can be controlled in such a way that the pressure set by the second pressure setting unit in the second container can be controlled.

[0018] The first pressure setting unit can be fluidically connected to the first container. The first pressure setting unit can be configured to exert the first pressure on the pressure medium contained in the first container when pressure medium is contained in the first container. The second pressure setting unit can be fluidically connected to the second container. The second pressure setting unit can be configured to exert the second pressure on the pressure medium contained in the second container when pressure medium is contained in the second container. In some embodiments, the first pressure setting unit can be arranged above the first container. In some embodiments, the second pressure setting unit can be arranged above the second container.

[0019] The first pressure control unit can be or include a proportional valve and / or a gas pump. The second pressure control unit can also be or include a proportional valve and / or a gas pump. The first pressure control unit can be connected to a positive pressure line and a negative pressure line. The second pressure control unit can also be connected to a positive pressure line and a negative pressure line. In some embodiments, the first pressure control unit and / or the second pressure control unit can adjust the pressure via a corresponding valve opening and / or valve position. In a first valve position, the pressure can correspond to the pressure specified by the positive pressure line. In a second valve position, the pressure can correspond to the pressure specified by the negative pressure line. Depending on the valve position, a selected pressure between these two extreme values ​​can be set.The valve can be continuously adjustable. In some embodiments, the pressure specified by the overpressure line can be from 0 to 6 bar, for example, 4 to 5 bar. In some embodiments, the pressure specified by the underpressure line can be or include a vacuum pressure. For example, the underpressure, relative to a reference external pressure, such as ambient pressure, can be between 0 and -1 bar, for example, between -0.1 and 1 bar. Underpressure can refer to a pressure lower than the reference pressure, ambient pressure, or standard pressure, e.g., lower than 1 bar. Overpressure can refer to a pressure higher than the reference pressure, ambient pressure, or standard pressure, e.g., higher than 1 bar. Underpressure can refer to a vacuum.

[0020] It may be provided that a fluid, for example a gas and / or a gas mixture, can be introduced from, through, or with the first pressure control unit into the first container, so that the pressure of the fluid introduced into the first container, e.g., due to gas pressure, can establish the first pressure in the container, and / or the fluid, e.g., the gas and / or gas mixture, can exert pressure on the pressure medium contained in the first container. It may also be provided that a fluid, for example a gas and / or a gas mixture, can be introduced from, through, or with the second pressure control unit into the second container, so that the pressure of the fluid introduced into the second container, e.g., due to gas pressure, can establish the second pressure in the container, and / or the fluid, e.g., the gas and / or gas mixture, can exert pressure on the pressure medium contained in the second container.

[0021] The first container can be fluidically connected to the printhead via a line. The first container can be fluidically connected to the printhead inlet via a line.

[0022] The first sensor can be located on, near, or in a line between the first reservoir and the printhead. It can be arranged that the first sensor is located on, near, and / or above the printhead. The first sensor can be located on, near, and / or above the printhead inlet. In some embodiments, the first sensor can be located as close as possible to the printhead and / or its inlet.

[0023] The second container can be fluidically connected to the printhead via a line. The second container can also be fluidically connected to the printhead outlet via a line.

[0024] The second sensor can be located on, near, or in a line between the second container and the printhead. It is possible for the second sensor to be located on, near, and / or above the printhead. The second sensor can also be located on, near, and / or above the printhead outlet. In In some embodiments, the second sensor can be positioned as close as possible to the printhead and / or its outlet. This allows for accurate determination of the flow rate of printing material into and / or through the printhead.

[0025] The first reservoir can be positioned at a first height above the printhead, and the second reservoir can be positioned at a second height above the printhead. The first height and / or the second height can be different. The first height and / or the second height can be defined, determined, and / or measured in the direction of gravity. The first height and / or the second height can correspond to a geodetic height above the printhead. Thus, the first height and / or the second height can correspond to a height difference between the liquid level of the ink in the reservoir and the printhead. Alternatively, the first height and / or the second height can correspond to the height difference between the outlet of the ink reservoir and the inlet of the printhead, measured in the direction of gravity.If the first height and the second height are different, a flow of pressurized medium to and / or through the printhead may be promoted and / or facilitated. In In some embodiments, a flow of pressure medium to and / or through the printhead can occur due to the difference in the first and second heights, gravity, and / or the pressure in the first container 3 and / or the second container 4. In other embodiments, one or more conveying means can be provided alternatively or additionally.

[0026] The first height and the second height can be chosen such that the meniscus pressure of the printhead can be between -50 mbar and 500 mbar.

[0027] The device may be designed so that the first height and / or the second height can be adjusted and / or varied. In some embodiments, the device may include a height adjustment unit. The height adjustment unit may be configured to set and / or vary the first height and / or the second height.

[0028] In some embodiments, the control unit can actuate and / or regulate the height adjustment unit, for example, depending on a predetermined meniscus pressure and / or depending on values ​​detected by one or more sensors. It may be provided that the control unit can actuate and / or regulate the first height and / or the second height.

[0029] The control unit can be configured to actuate the first and second pressure setting units such that the printhead meniscus pressure is between -50 mbar and 500 mbar, for example, between -50 and 250 mbar or between 5 mbar and 250 mbar. The first and second pressure setting units can be actuated to set and / or control the printhead meniscus pressure, for example, between -50 mbar and 500 mbar, or between -50 mbar and 250 mbar or between 20 mbar and 250 mbar. The meniscus pressure can be defined and / or measured on the underside of the printhead. The meniscus pressure can correspond to a vacuum on the underside of the printhead, for example, in a nozzle channel of the printhead.

[0030] The first pressure can be an overpressure. The second pressure can be a vacuum. The first pressure can be greater than the second pressure. The first pressure and / or the second pressure can be gas pressure.

[0031] The first sensor can be a pressure sensor. Alternatively or additionally, the first sensor can be a temperature sensor. The property detected by the first sensor can be the pressure and / or temperature of the pressure medium.

[0032] The second sensor can be a pressure sensor. Alternatively or additionally, the second sensor can be a temperature sensor. The property detected by the second sensor can be the pressure and / or temperature of the pressure medium.

[0033] The first and second sensors can be configured to detect the pressure of the pressure medium. The control unit can be configured to determine the pressure difference between the pressures detected by the first and second sensors and to control the first and / or second pressure setting unit based on this pressure difference. Alternatively or additionally, the control unit can be configured to determine an average of the pressures detected by the first and second sensors and to control the first and / or second pressure setting unit based on this average. In some embodiments, it can alternatively or additionally be provided that the first and / or second pressure setting unit is controlled based on the pressures detected by the first and / or second sensors.

[0034] In some embodiments, the first and second sensors may be configured to detect the temperature of the pressure medium. The control unit may be configured to detect temperature deviations from a setpoint. The device may include a temperature control unit. The temperature control unit may, for example, be a heating unit and / or a cooling unit. The temperature may be regulated within the setpoint range. The control unit may control and / or regulate the temperature control unit. In some embodiments, the temperature control unit may be configured to set the temperature of the pressure medium and / or to heat and / or cool the pressure medium. The temperature control unit may be located in the reservoir and / or a second reservoir. Description of exemplary implementations

[0035] The following section explains an exemplary embodiment in more detail with reference to a figure in a drawing. This shows: Fig. 1 is a schematic representation of a device according to the invention.

[0036] Fig. 1 Figure 1 shows a schematic representation of a device 1 according to the invention. The device 1 has a printhead 2. The printhead 2 can be used to print printing medium onto or into a printing substrate. The printhead 2 can have one or more nozzles from which printing medium, for example ink, can be or will be ejected.

[0037] The device 1 can be or comprise a printer, e.g., an inkjet printer. The printing substrate can be or comprise a substrate to be printed, a surface to be printed, a body to be printed, and / or the like. The printing substrate can be, for example, paper, cardboard, or the like. The printing substrate can be or comprise a laminate and / or a plastic object. However, the printing substrate is not limited to these examples. "Printing" can mean that printing media can be printed onto the printing substrate and / or that printing media can be printed into the printing substrate.

[0038] The printhead 2 may be configured to print the substrate using a piezoelectric method. In some embodiments, the substrate may be printed using drop-on-demand technology. Alternatively or additionally, other printing methods, such as bubble jet printing, are also possible. The device 1 and / or the printhead 2 may be a piezoelectric inkjet printer, or a component thereof. In some embodiments, the device 1 and / or the printhead 2 may alternatively or additionally be a mechanical inkjet printer, or a component thereof.

[0039] The device 1 comprises a first container 3 and a second container 4. The first container 3 and the second container 4 can be configured to receive, store, and / or hold pressure medium. The first container 3 is fluidically connected to the printhead 2, allowing pressure medium to flow from the first container 3 into the printhead 2. For example, the first container 3 can be fluidically connected to an inlet 9 of the printhead 2. The first container 3 can also be fluidically connected to the printhead 2 via a line 12.

[0040] The second container 4 is fluidically connected to the printhead 2, allowing pressure medium to flow from the printhead 2 into the second container 4. For example, an outlet 10 of the printhead 2 can be fluidically connected to the second container 4. The printhead 2 can also be fluidically connected to the second container 4 via a line 13.

[0041] The first container 3 can have a volume between 10 ml and 100 ml, preferably between 10 ml and 50 ml. The first container 3 can have a volume less than 50 ml. The second container 4 can have a volume between 10 ml and 100 ml, preferably between 10 ml and 50 ml. The second container 4 can have a volume less than 50 ml. The volume of the first container 3 can differ from the volume of the second container 4, for example, it can be smaller or larger. Alternatively, the volumes of the first container 3 and the second container 4 can be the same.

[0042] The line 12, 13 can be or comprise a hose. For example, the hose can be made of a plastic and / or plastic material. The line 12, 13 and / or the hose can be coated. The coating can, for example, be or comprise an ETFE coating. An ETFE coating can be provided, for example, if the printing medium is a solvent-based ink and / or if the printing medium is a UV ink. In some embodiments, the inner diameter of the line 12, 13, and / or the hose can be between 2 mm and 6 mm, preferably between 5 mm and 6 mm. In some embodiments, the outer diameter of the line 12, 13, and / or the hose can be between 4 mm and 10 mm, preferably between 8 mm and 10 mm.

[0043] In some embodiments, a filter (not shown in the figures) may be arranged in line 12 and / or line 13, and / or fluidically between printhead 2 and second container 4, and / or between printhead 2 and first container 3. Alternatively, it may be provided that no filter is arranged in line 12 and / or line 13, and / or that no filter is fluidly arranged between printhead 2 and second container 4.

[0044] It may be provided that a shut-off valve is arranged in line 12 and / or line 13, and / or that line 12 and / or line 13 has a shut-off valve. The shut-off valve may be configured to prevent and / or block the flow of pressure medium through the respective line 12 and / or line 13. This allows, for example, when the device 1 and / or the method is in a standstill state, the flow of pressure medium from the first container 3 and / or the second container 4 to the pressure head 2, and / or from the pressure head 2 to the respective containers 3 and 4, to be prevented and / or blocked. With the flow of pressure medium blocked, refilling of pressure medium and / or pressure regulation in the first container 3 and / or the second container 4 may be facilitated, or alternatively, or additionally.Furthermore, leakage of ink through the printhead in standby mode can be prevented or made possible.

[0045] It may be provided that the first container 3 and the second container 4 are or can be combined to form a container unit 26. It may be provided that the container unit 26 is designed such that it can form a first container 3 and / or a second container 4. The first container 3 may be fluidically separated from the second container 4.

[0046] It may be provided that the first container 3 is or can be a pressurized container, and / or can have an overpressure. In some embodiments, the first pressure can be an overpressure.

[0047] It may be provided that the second container 4 is or can be a vacuum container, and / or can have a negative pressure and / or a vacuum. In some embodiments, the second pressure can be a negative pressure and / or a vacuum.

[0048] The first container 3 and / or the second container 4 can be arranged above and / or located above the printhead 2. The first container 3 and / or the second container 4 can, for example, be arranged in a plane that is vertically and / or perpendicularly spaced from a plane in which the printhead 2 may be located. The first container 3 and / or the second container 4 can be arranged at a height that is above the height at which the printhead 2 is located.

[0049] The first container 3 can be arranged at a first height above the printhead 2. The second container 4 can be arranged at a second height above the printhead 2. The first height can differ from the second height. The first height can be greater than the second height, and / or the first container 3 can be arranged at a higher height than the second container 4 above the printhead 2. Alternatively, the second height can be greater than the first height, and / or the second container 4 can be arranged at a higher height than the first container 3 above the printhead 2. It can also be arranged that the first height is the same as the second height, and / or that the first container 3 can be arranged at the same height as the second container 4 above the printhead 2.

[0050] It may be provided that the respective heights above printhead 2 can be determined, defined, and / or measured in the direction of gravity. The first height and / or the second height can correspond to a geodetic height above printhead 2, i.e., the height difference between the liquid level of the ink in the reservoir and the printhead, or the height difference between the outlet of the ink reservoir and the inlet of the printhead, measured in the direction of gravity.

[0051] If the first container 3 and the second container 4 are arranged at different heights, a flow of pressure medium to the printhead 2, and / or a flow of pressure medium through the printhead 2, may be facilitated or made easier due to the height difference, and / or a corresponding flow may occur.

[0052] InIn some embodiments, valves may be provided to prevent and / or block an unwanted flow of printing medium to the printhead 2, and / or a flow of printing medium through the printhead 2. For example, such a flow may be blocked when no printing is taking place and / or the process is not being carried out.

[0053] In In some embodiments, the height of the first container 3 and / or the second container 4 above the printhead 2 may be adjustable and / or variable. For example, a suitable height adjustment mechanism may be provided for this purpose. The device may include a height adjustment unit that can be configured to adjust and / or vary the height of the first container 3 and / or the second container 4 above the printhead 2.

[0054] It may be provided that the relative height and / or height difference of the first container 3 and the second container 4 can be set and / or varied. For example, it may be provided that the height of the first container 3 and / or the second container 4 above the printhead 2 can be set and / or varied depending on one or more of the following: predetermined and / or desired meniscus pressure, fill level of printing medium in the first container 3 and / or the second container 4, and / or during printing and / or during the execution of the process.

[0055] The distance between a liquid column and the underside of the printhead 2 can be between -1000 and 1000 mm, preferably between 150 mm and 500 mm. The liquid column can contain a level of pressure medium in the first container 3 and / or the second container 4. Alternatively or additionally, the liquid column can comprise pressure medium present in the line 12, 13 connecting the respective containers 3, 4 to the printhead 2.

[0056] The distance of the liquid column can be defined, determined, and / or measured from a surface of the liquid column, e.g., the surface of the pressure medium in a corresponding container 3, 4, to the underside of the printhead 2. Alternatively or additionally, the distance of the liquid column can be defined, determined, and / or measured from a bottom surface of the first container 3 and / or the second container 4 to the underside of the printhead 2.

[0057] In some embodiments, the distance can be defined, determined and / or measured in the direction of gravity. In In some embodiments, the distance can alternatively or additionally comprise a length of one of the lines 12, 13.

[0058] It can be provided that the first container 3 and / or the second container 4 is or will be filled with pressure medium such that the respective liquid column, fill level, and / or fill height has a predetermined value and / or lies within a predetermined interval. For example, filling can be achieved by refilling the first container 3 and / or the second container 4 with pressure medium. Alternatively or additionally, filling can involve a flow of pressure medium through a return line 11.

[0059] The first height and / or the second height can be selected depending on a predetermined distance between a liquid column and the underside of the printhead 2, for example depending on a predetermined interval of a respective liquid column, a predetermined interval of a respective fill level and / or a predetermined interval of a respective fill level.

[0060] It may be provided that the first height and / or the second height are selected such that a vacuum is or becomes established in the first reservoir 3 and the second reservoir 4, and / or may be necessary, so that ink can flow through the printhead. The first height and / or the second height may be selected or become established such that the ink can flow through the printhead 2 with a predetermined meniscus pressure in the printhead 2, and / or on a lower surface of the printhead 2.

[0061] In some embodiments, the first height and / or the second height can be selected such that the meniscus pressure can be between -50 mbar and 500 mbar, preferably between 20 mbar and 250 mbar, and particularly preferably between 20 mbar and 250 mbar.

[0062] To print on a substrate, printing medium from the first reservoir 3 can be supplied to the printhead 2. At least a portion of the supplied printing medium can be ejected through nozzles of the printhead 2 to print on the substrate. The portion of the printing medium that is not ejected can be conveyed from the printhead 2 to the second reservoir 4.

[0063] The printing medium can be a liquid or contain ink. For example, the printing medium can be ink or contain solvents.

[0064] The first container 3 can provide the printing medium used for printing, e.g. ink, and the second container 4 can receive excess and / or too much printing medium.

[0065] To achieve good print quality, precise adjustment of the meniscus pressure of the printhead 2 may be necessary. Meniscus pressure can refer to a vacuum on the underside of the printhead 2 in a nozzle and / or nozzle channel. The meniscus pressure can retain printing medium, such as ink, to prevent leakage from the printhead. For example, in a drop-on-demand process, it may be necessary to retain printing medium between intended droplets to prevent unintended release of printing medium from the nozzle. Alternatively or additionally, the meniscus pressure may be used to tension the surface of the printing medium in the nozzle and / or nozzle channel after a droplet has been dispensed, thus preventing or at least reducing the escape of satellite droplets after dispensing.

[0066] In some embodiments, the meniscus pressure can be precisely set, controlled, and / or regulated. This can improve print quality. In some embodiments, the meniscus pressure can be set, controlled, or regulated between -50 and 500 mbar, or between -50 and 250 mbar, or between 20 and 250 mbar. In some embodiments, deviations of ± 5 mbar or less can be achieved.

[0067] The device 1 comprises a first sensor 7 and a second sensor 8. The first sensor 7 is configured to detect a property of the pressure medium as it flows from the first container 3 to the printhead 2. The second sensor 8 is configured to detect a property of the pressure medium as it flows from the printhead 2 to the second container 4. The property of the pressure medium can be a state variable of the pressure medium. The property and / or state variable of the pressure medium can be a pressure and / or a temperature of the pressure medium. The first sensor 7 can be arranged on, at, or in the line 12 through which the pressure medium can flow from the first container 3 to the printhead 2. The second sensor 8 can be arranged on, at, or in the line 13 through which the pressure medium can flow from the printhead 2 to the second container 4.

[0068] The first sensor 7 can be or comprise a pressure sensor and / or a temperature sensor. The second sensor 8 can be or comprise a pressure sensor and / or a temperature sensor. In some embodiments, the first sensor 7 and / or the second sensor 8 can be or comprise a combined pressure and temperature sensor and / or be configured to detect both the temperature and pressure of the pressure medium.

[0069] The first sensor 7 and / or the second sensor 8 may be arranged on or near the printhead 2. In some embodiments, the first sensor 7 and / or the second sensor 8 may be arranged close to the printhead 2. In some embodiments, the first sensor 7 may be arranged on and / or at, or at least near, the inlet 9 of the printhead 2. In some embodiments, the second sensor 8 may be arranged on and / or at, or at least near, the outlet 10 of the printhead 2. The property detected by the first sensor 7 may correspond to the corresponding local value of the pressure medium at the inlet 9 of the printhead 2. The property detected by the second sensor 8 may correspond to the corresponding local value of the pressure medium at the outlet 10 of the printhead 2.

[0070] For example, if the first sensor 7 is located close to the inlet 9, a measured pressure may correspond to the pressure of the pressure medium at or in the inlet 9. Similarly, if the second sensor 8 is located close to the outlet 10, a measured pressure may correspond to the pressure of the pressure medium at or in the outlet 10.

[0071] The device 1 comprises a first pressure setting unit 5 and a second pressure setting unit 6. The first pressure setting unit 5 is configured to set a first pressure in the first container 3. The second pressure setting unit 6 is configured to set a second pressure in the second container 4.

[0072] In some embodiments, the first pressure setting unit 5 and / or the second pressure setting unit 6 may be or include a proportional valve. For example, the first pressure setting unit 5 and / or the second pressure setting unit 6 may be equipped with a (not shown in the image) Figure 1 (shown) overpressure line and / or a (not in Figure 1 The vacuum line shown is or will be fluidically connected.

[0073] In some embodiments, the first pressure setting unit 5 can set the first pressure depending on a valve position. The second pressure setting unit 6 can, for example, set the second pressure depending on a valve position. In a first valve position, the first pressure and / or second pressure can correspond to the pressure provided by the overpressure line. In a second valve position, the first and / or second pressure can correspond to the pressure provided by the vacuum line. Depending on the valve position between the first and second valve positions, the first and / or second pressure can lie between these pressures. It may be provided that the first pressure and / or second pressure can be set, controlled, regulated, and / or selected by controlling the respective valve position and / or the first pressure setting unit 5 and / or the second pressure setting unit 6.

[0074] In some embodiments, the pressure relief line can provide a pressure of 0 to 6 bar. In some embodiments, the vacuum relief line can provide a pressure of 0 to -1 bar.

[0075] Alternatively or additionally, the first pressure setting unit 5 and / or the second pressure setting unit 6 can be or include a gas pump. A corresponding gas pump can be configured to adjust, control, or regulate the first and / or the second pressure accordingly.

[0076] It may be provided that a fluid, for example a gas and / or a gas mixture, can be introduced from, through or with the first pressure setting unit 5 into the first container 3, so that the first pressure in the first container 3 can be set due to the pressure of the fluid introduced into the first container 3, e.g. due to a gas pressure, and / or the fluid, e.g. the gas and / or gas mixture, can exert a pressure on the pressure medium received in the first container 3.

[0077] The initial pressure in the first container 3 can be or be a gas pressure. The initial pressure can act on pressure medium held and / or absorbed in the first container 3.

[0078] It may be provided that a fluid, for example a gas and / or a gas mixture, can be introduced from, through or with the second pressure setting unit 6 into the second container 4, so that the second pressure in the second container 4 can be set due to the pressure of the fluid introduced into the second container 4, e.g. due to a gas pressure, and / or the fluid, e.g. the gas and / or gas mixture, can exert a pressure on the pressure medium contained in the second container 4.

[0079] The second pressure in the second container 4 can be or be a gas pressure. The second pressure can act on pressure medium held and / or absorbed in the second container 4.

[0080] The first pressure setting unit 5 can be located outside the first container 3. The first pressure setting unit 5 can be located above the first container 3. For example, the first pressure setting unit 5 can be located at a height above the first container 3. The first pressure setting unit 5 can be fluidically connected to the first container 3 via a line 16.

[0081] The second pressure setting unit 6 can be located outside the second container 4. The second pressure setting unit 6 can be located above the second container 4. For example, the second pressure setting unit 6 can be located at a height above the height of the second container 4. The second pressure setting unit 6 can be fluidically connected to the second container 4 via a line 17.

[0082] Device 1 has a (not in Figure 1The control unit shown can be connected to the first sensor 7 and / or the second sensor 8, and / or receive values ​​detected by the first sensor 7 and / or the second sensor 8. The control unit can be connected to the first pressure setting unit 5 and / or the second pressure setting unit 6 to control and / or regulate them.

[0083] The control unit can be or include a microcontroller. The control unit can include an FPGA, an integrated circuit, a logic circuit, a computer unit, and / or a microprocessor.

[0084] In some embodiments, the first sensor 7 and the second sensor 8 may each detect a pressure of the pressure medium. The control unit may be configured to calculate an average value and / or a pressure differential from the pressures detected by the first sensor 7 and the second sensor 8. Based on the calculated average value and / or the pressure differential, the control unit may be configured to control and / or regulate the first pressure setting unit 5 and / or the second pressure setting unit 6. Alternatively or additionally, in some embodiments, the control unit may be able to control and / or regulate the first pressure setting unit 5 and / or the second pressure setting unit 6 based on the pressure detected by the first sensor 7 and / or the second sensor 8.

[0085] The control and / or regulation of the first pressure setting unit 5 and / or the second pressure setting unit 6 can be continuous. The measurement of the pressure of the pressure medium can be continuous.

[0086] The device 1 and / or the method may comprise an operating state and a rest state. The rest state may be a standby state. The device 1 and / or the method may be switched off in the rest state.

[0087] It may be provided that the control and / or regulation of the first pressure setting unit 5 and / or the second pressure setting unit 6, and / or the measurement of the pressure of the pressure medium, can take place, preferably continuously, when the device 1 and / or the method is in the operating state. It may be provided that the control and / or regulation of the first pressure setting unit 5 and / or the second pressure setting unit 6, and / or the measurement of the pressure of the pressure medium, does not take place when the device 1 and / or the method is at rest.

[0088] It may be provided that, in the resting state, no pressure medium can flow through the printhead 2 and / or between the first container 3 and the second container 4 and / or circulate. For example, if a filter is arranged in line 13, this can prevent or at least reduce dilution of the pressure medium.

[0089] The pressure differential can, for example, correspond to the pressure difference between inlet 9 and outlet 10 of printhead 2. This pressure differential can thus determine and / or represent the flow rate of the printing medium through printhead 2. The pressure differential can, for example, represent or correspond to the flow rate of the printing medium to and / or through the printhead. This allows for simple and straightforward control and / or regulation of the flow rate and / or the flow velocity.

[0090] The average pressure value can, for example, correspond to, approximate, and / or represent the meniscal pressure. This allows for simple and straightforward control and / or regulation of the meniscal pressure.

[0091] Alternatively or additionally, it may be provided that the control unit can control and / or regulate the first pressure setting unit 5 and / or the second pressure setting unit 6 based on the temperature detected by the first sensor 7 and / or the second sensor 8. In In some embodiments, an average value and / or a difference of the temperature detected by the first sensor 7 and / or the second sensor 8 can be calculated, and based on the average value and / or the difference, and / or based on an absolute value of one or both temperature values, a temperature control unit of the device 1, for example a heating unit and / or a cooling unit of the temperature control unit, can be controlled and / or regulated.

[0092] InIn some embodiments, the first sensor 7 and / or the second sensor 8 may be configured to detect and / or measure the pressure of the pressure medium with an accuracy of ± 2 mbar or less. In some embodiments, the first sensor 7 and / or the second sensor 8 may be configured to detect and / or measure the temperature of the pressure medium with an accuracy of ± 1 K or less.

[0093] In In some embodiments, the device 1 can be (not in Figure 1The temperature control unit shown may be a heating unit and / or a cooling unit. The temperature control unit may be configured to heat and / or cool hydraulic fluid, bring it to a predetermined temperature, and / or supply hydraulic fluid at a predetermined temperature. The control unit may be connected to and control and / or regulate the temperature control unit. The control unit may be capable of setting or specifying the predetermined temperature. In In some embodiments, the control unit can control and / or regulate the temperature control unit in such a way that a temperature detected by the first sensor 7 and / or the second sensor 8 can deviate by less than ± 1 K from a temperature setpoint.

[0094] The temperature control unit, and / or a heating unit and / or a cooling unit, can be arranged on, in or near a container, for example on, in or near the first container 3 and / or the second container 4.

[0095] The heating unit may comprise one or more heating mats arranged in the first container 3 and / or the second container 4. The heating unit may also comprise one or more heating coils or heating filaments.

[0096] The cooling unit may include a water cooling system. In some embodiments, the cooling unit, and / or the water cooling system, may include a proportional valve, which may be located, for example, at or near an inlet to the first container 3 and / or the second container 4, such as an inlet in the area of ​​a recirculation line or a return line 14. The proportional valve may control and / or regulate the flow rate of cooling water, thus controlling and / or regulating the cooling process.

[0097] It may be provided that, depending on the properties detected by the first sensor 7 and / or the second sensor 8, e.g., pressure and / or temperature, the first pressure in the container 3 and / or the second pressure in the container 4 can be set, controlled, regulated, and / or selected. It may also be provided that, depending on the properties detected by the first sensor 7 and / or the second sensor 8, e.g., pressure and / or temperature, the first pressure setting unit 5 and / or the second pressure setting unit 6 can be set, controlled, regulated, and / or selected.

[0098] It may be provided that by controlling and / or regulating the first pressure setting unit 5 and / or the second pressure setting unit 6, and / or the first pressure in the first container 3 and / or the second pressure in the second container 4, the delivery rate and / or the meniscus pressure of the printhead 2 can be controlled and / or regulated.

[0099] It may be provided that the meniscus pressure can be controlled and / or regulated with a deviation of less than ± 5 mbar, e.g., compared to a predetermined and / or adjustable meniscus pressure. For example, the first pressure setting unit 5 and / or the second pressure setting unit 6, and / or the first pressure in the first container 3 and / or the second pressure in the second container 4, can control and / or regulate the meniscus pressure with a deviation of less than ± 5 mbar, e.g., compared to a predetermined and / or adjustable meniscus pressure.

[0100] It may be provided that the pressure differential can be controlled and / or regulated with a deviation of less than ± 5 mbar, e.g., compared to a predetermined and / or adjustable pressure differential. For example, the pressure differential can be controlled and / or regulated with a deviation of less than ± 5 mbar by the first pressure setting unit 5 and / or the second pressure setting unit 6, and / or by the first pressure in the first container 3 and / or the second pressure in the second container 4, e.g., compared to a predetermined and / or adjustable pressure differential.

[0101] In some embodiments, the device 1 may include a third sensor 20. The third sensor 20 may, for example, be a velocity sensor capable of detecting the flow velocity of the pressure medium. Alternatively or additionally, the third sensor 20 may, for example, be a flow sensor capable of detecting the volumetric flow rate of the pressure medium. Alternatively or additionally, the third sensor 20 may be a viscosity sensor and / or detect the viscosity of the pressure medium. Alternatively or additionally, the third sensor 20 may be a temperature sensor and / or detect the temperature of the pressure medium. The control unit may be connected to the third sensor 20 and receive values ​​detected by it. It may be provided that, when adjusting the pressure and / or temperature in the first container 3 and / or the second container 4, the control unit can take into account the values ​​detected by the third sensor 20.

[0102] Alternatively or additionally, the device 1 can have a further sensor (not shown in the figures) which can be arranged on, in, or near the first container 3 and / or the second container 4. In some embodiments, a further sensor can be arranged in both the first container 3 and the second container 4. The further sensor can be configured to detect the pressure in the respective container 3, 4. The further sensor can be connected to the control unit and / or exchange data with the control unit. It can be provided that, when adjusting the pressure in a respective container 3, 4, the control unit can take into account the values ​​detected by the further sensor.

[0103] In some embodiments, it may be provided that a (not in Figure 1The filter shown may be provided between the first container 3 and printhead 2, and / or printhead 2 and the second container 4. A corresponding filter may, for example, be provided and / or arranged on and / or in line 12 and / or line 13. The filter may be configured to be or be subjected to flow by the printing medium. The filter may be configured to draw and / or remove undissolved air from the printing medium, e.g., ink. The filter may be configured to filter out foreign bodies, impurities, flakes, clumps, agglomerates, or the like from the printing medium.

[0104] In some embodiments, the first container 3 may have a level sensor 19, and / or a level sensor 19 may be arranged on, in, and / or near the first container 3. Alternatively or additionally, the second container 4 may have a level sensor 19, and / or a level sensor 19 may be arranged on, in, and / or near the second container 4. The level sensor 19 may be configured to detect a fill level, in particular of pressure medium, in the respective container. It may be provided that the control unit can be connected to the level sensor 19 in order to receive values ​​detected by the level sensor 19, in particular a fill level.

[0105] Alternatively or additionally, the first container 3 and / or the second container 4 may have a sight glass, and / or a side wall of the first container 3 and / or the second container 4 may be at least partially transparent. This allows for visual monitoring of the fill level of the first container 3 and / or the second container 4. Visual monitoring may be advantageous and / or more reliable than, for example, a float or other sensor, as the float may, in some cases, become stuck to the container rim. Alternatively or additionally, it may be possible to use visual monitoring to check whether the pressurizing medium in the respective container 3, 4 is foaming.

[0106] Lighting may be provided, which may facilitate and / or improve visual inspection depending on the type of visual inspection and / or the environment. The lighting may be located on, at, or in the first container 3 and / or the second container 4, and / or the sight glass.

[0107] Alternatively or additionally, the fill level can be measured using at least one capacitive sensor. Alternatively or additionally, the fill level can be determined based on the pressure difference, and / or using the pressure difference.

[0108] The device 1 can include a return line 11 for returning hydraulic fluid from the second container 4 to the first container 3. For example, the second container 4 can be fluidically connected to the first container 3 via a return line 14. The return line 11 can include the return line 14. The device 1 and / or the return line 11 can include a pump 24 for conveying and / or returning hydraulic fluid from the second container 4 to the first container 3. The pump 24 can be located on or in the return line 14, and / or fluidically between the first container 3 and the second container 4. Alternatively or additionally, the pump 24 can be located in the first container 3 and / or the second container 4, and / or be integrated into the first container 3 and / or the second container 4.For example, if the pump 24 is located in, and / or integrated into, the first tank 3 and / or the second tank 4, space savings, and / or easier maintenance and / or accessibility may result. The pump 24 can be low-vibration and / or generate only minimal vibration during operation, thus enabling its location and / or integration within the first tank 3 and / or the second tank 4. The pump 24 can, for example, be a micro gear pump, which can be low-vibration and / or essentially pulse-free during flow. This can result, for example, in the placement and / or integration within a tank 3 or 4, in a pressure setting and / or flow of hydraulic fluid to and / or from the pressure head 2 that is essentially undisturbed by the pump 24.

[0109] The device 1 and / or the return line 11 may include a filter 23 that filters the pressure medium returned from the second container 4 to the first container 3. For example, the filter 23 may be located in the return line 14 and / or be or be subjected to a flow of pressure medium during the return process. The filter 23 may be configured to be or be subjected to a flow of pressure medium. The filter 23 may be configured to draw out and / or remove undissolved air from the pressure medium, e.g., ink. The filter 23 may be configured to filter out foreign bodies, impurities, flakes, lumps, or the like from the pressure medium.

[0110] In some embodiments, the control unit can be connected to the pump 24 and / or control and / or regulate the pump 24. In some embodiments, the control unit can be configured to control the pump 24 based on the fill level at the ends of the first container 3 and / or the second container 4. In some embodiments, the pressure medium can be recirculated or returned in such a way that the fill level of the first container 3 substantially corresponds to, and / or differs from, the fill level of the second container 4.

[0111] In some embodiments, it may alternatively be provided that the device 1 does not have a return of pressure medium, in particular no return line 14, no filter 23 and / or no pump 24.

[0112] In some embodiments, the first container 3 and / or the second container 4 may have a temperature sensor 21, and / or a temperature sensor 21 may be arranged on, in, and / or near the first container 3 and / or the second container 4. The temperature sensor 21 may be configured to detect the temperature of the pressurizing medium contained in the first container 3 and / or the second container 4. The temperature sensor 21 may be connected to the control unit, and the control unit may receive values ​​detected by the temperature sensor 21.

[0113] In some embodiments, the device 1 may have a reservoir 25. The reservoir 25 may hold and / or receive pressure medium. The reservoir 25 may serve to replenish pressure medium, for example, when pressure medium is used or has been used for printing. The reservoir 25 may be fluidically connected to the first container 3. The reservoir 25 may be connected to the first container 3 via a supply line 15. The device 1 may have a supply pump 24. The supply pump 27 may be used and / or configured to supply and / or deliver pressure medium from the reservoir 25 to the first container 3. The control unit may be connected to the supply pump 27 and / or be able to control and / or regulate the supply pump 27.In some embodiments, it may be provided that if the fill level in the first container 3 falls below a minimum level, the feed pump 27 can be controlled such that pressure medium can flow from the reservoir 25 into the first container 3. The feed pump 27 may be a micro gear pump.

[0114] In some embodiments, a filter 23 may be provided that filters the printing medium supplied to the first container 3 from the reservoir 25. For example, the filter 23 may be arranged on and / or in the supply line 15. The filter 23 may be configured to be or be subjected to flow through the printing medium. The filter 23 may be configured to draw out and / or remove undissolved air from the printing medium, e.g., ink. The filter 23 may be configured to filter out foreign bodies, impurities, flakes, lumps, or the like from the printing medium.

[0115] In some embodiments, it may alternatively or additionally be provided that pressure medium from reservoir 25 can be supplied to the second container 4. It may also be provided that pressure medium from reservoir 25 can be supplied to both the first container 3 and the second container 4.

[0116] The device 1 can have at least one sealing valve 22. In some embodiments, the sealing valve 22 can be associated with the first container 3 and / or configured to seal and / or calibrate the first container 3. It can be provided that the sealing valve 22 is fluidically arranged between the first container 3 and the first pressure setting unit 5 and / or can fluidly calibrate the first container 3 against the first pressure setting unit 5. InIn some embodiments, the sealing valve 22 can be arranged on or in the line 16. It can be provided that the control unit can be connected to the sealing valve 22 and / or control and / or regulate the sealing valve 22.

[0117] In some embodiments, the sealing valve 22 may be associated with the second container 4 and / or configured to seal and / or calibrate the second container 4. The sealing valve 22 may be arranged fluidically between the second container 4 and the second pressure control unit 6 and / or fluidically calibrate the second container 4 against the second pressure control unit 6. In some embodiments, the sealing valve 22 may be arranged on or in the line 17. The control unit may be connected to the sealing valve 22 and / or control and / or regulate the sealing valve 22.

[0118] In some embodiments, a sealing valve 22 can be assigned to the first container 3 and another sealing valve 22 can be assigned to the second container 4, and / or seal and / or close the respective containers.

[0119] The sealing valve 22 can, in particular when the device 1 and / or the inkjet printer is in a standby state and / or is being moved into a standby state, seal and / or close the first container 3 and / or the second container 4. This ensures that no printing medium can escape from the printhead 2 in the standby state, e.g., it cannot drip out.

[0120] The features disclosed in the foregoing description, the claims and the drawing may be essential for the realization of the invention, both individually and in any combination. Reference symbol list

[0121] 1 Device 2 Printhead 3 First tank 4 Second tank 5 First pressure setting unit 6 Second pressure setting unit 7 First sensor 8 Second sensor 9 Inlet 10 Outlet 11 Return 12 Line 13 Line 14 Return line 15 Feed line 16 Line 17 Line 18 Bottom 19 Level sensor 20 Third sensor 21 Temperature sensor 22 Valve seal 23 Filter 24 Pump 25 Reservoir 26 Tank unit 27 Feed pump

Claims

1. Device (1) for printing on a printing substrate, comprising: - a printhead (2) for printing on a printing substrate with a printing medium, - a first container (3) for receiving the printing medium, - a second container (4) for receiving the printing medium, - a first pressure setting unit (5), - a second pressure setting unit (6), - a first sensor (7), - a second sensor (8), and - a control unit, wherein the first container (3) is fluidically connected to an inlet of the printhead (2) and the second container (4) is fluidically connected to an outlet (10) of the printhead (2), such that printing medium can flow from the first container (3) through the printhead (2) into the second container (4), wherein the first sensor (7) is configured to detect a property of the printing medium when printing medium flows from the first container (3) to the printhead (2), and the second sensor (8) is configured to detect a property of the printing medium when printing medium flows from the first container (3) to the printhead (2). capture,when pressure medium flows from the printhead (2) to the second container (4), wherein the first pressure setting unit (5) is configured to set a first pressure on or in the first container (3) and the second pressure setting unit (6) is configured to set a second pressure on or in the second container (4), wherein the control unit is configured to control the first pressure setting unit (5) and / or the second pressure setting unit (6) based on the property detected by the first sensor (7) and / or the second sensor (8), wherein preferably the property detected by the first sensor (7) and / or the second sensor (8) is a pressure of the pressure medium.

2. Device (1) according to claim 1, wherein the control unit is configured to control the first pressure setting unit (5) and the second pressure setting unit (6) such that a meniscus pressure of the printhead (2) is between -50 mbar and 500 mbar, preferably between -50 mbar and 250 mbar, particularly preferably between 20 mbar and 250 mbar.

3. Device (1) according to one of the preceding claims, wherein the control unit is configured to control, based on the property detected by the first sensor (7) and / or the second sensor (8), the pressure set by the first pressure setting unit (5) in the first container (3) and / or the pressure set by the second pressure setting unit (6) in the second container (4).

4. Device (1) according to one of the preceding claims, wherein the first sensor (7) and the second sensor (8) are configured to detect a pressure of the pressure medium, and the control unit is configured to determine a pressure difference of the pressures detected by the first sensor (7) and the second sensor (8) and to control the first pressure setting unit (5) and / or the second pressure setting unit (6) based on the pressure difference.

5. Device (1) according to one of the preceding claims, wherein the first sensor (7) and the second sensor (8) are configured to detect a pressure of the pressure medium, and the control unit is configured to determine an average of the pressures detected by the first sensor (7) and the second sensor (8) and to control the first pressure setting unit (5) and / or the second pressure setting unit (6) based on the average.

6. Device (1) according to one of the preceding claims, wherein the first pressure setting unit (5) is fluidically connected to the first container (3), and / or wherein the second pressure setting unit (6) is fluidically connected to the second container (4).

7. Device (1) according to one of the preceding claims, wherein the pressure setting unit (5) is configured to exert the first pressure on pressure medium received in the first container (3) when pressure medium is received in the first container (3), and / or wherein the second pressure setting unit (6) is configured to exert the second pressure on pressure medium received in the second container (4) when pressure medium is received in the second container (4).

8. Device (1) according to any of the preceding claims, wherein the first pressure setting unit (5) and / or the second pressure setting unit (6) is or comprises a proportional valve and / or a gas pump.

9. Device (1) according to one of the preceding claims, wherein the first pressure setting unit (5) and / or the second pressure setting unit (6) are connected to an overpressure line and a vacuum line, wherein preferably the first pressure is an overpressure and / or a vacuum, and / or preferably the second pressure is a vacuum and / or an overpressure.

10. Device (1) according to one of the preceding claims, wherein the first sensor (7) is arranged on, at or in a line (12) between first container and printhead (2), and / or the second sensor (8) is arranged on, at or in a line (13) between printhead (2) and second container, and / or wherein the first sensor (7) and / or second sensor (8) is arranged on, at, and / or above the printhead (2).

11. Device according to one of the preceding claims, wherein the first container (3) is arranged at a first height above the printhead (2) and the second container (4) is arranged at a second height above the printhead (2), preferably the first height being different from the second height.

12. Device (1) according to claim 11, wherein the first height and the second height are selected such that the meniscus pressure of the print head (2) is between -50 mbar and 500 mbar.

13. Method for controlling a device (1) for printing on a printing substrate, comprising the steps of: - detecting a property of a pressure medium flowing from a first container (3) of the device (1) to a printhead (2) of the device (1) with a first sensor (7); - detecting a property of a pressure medium flowing from the printhead (2) to a second container (4) of the device (1) with a second sensor (8); - controlling, based on the properties of the pressure medium detected by the first and second sensors (8), a first pressure setting unit (5) of the device (1), wherein the first pressure setting unit (5) sets a first pressure on or in the first container (3) based on the properties detected by the first and second sensors (8);and - control, based on the properties of the pressure medium detected by the first and second sensors (8), a second pressure setting unit (6) of the device (1), wherein the second pressure setting unit (6) sets a second pressure on or in the first container (3) based on the properties detected by the first and second sensors (8).

14. Method according to claim 13, wherein the first pressure setting unit (5) and the second pressure setting unit (6) are controlled such that a meniscus pressure of the printhead (2) is between -50 mbar and 500 mbar, preferably between -50 mbar and 250 mbar, and particularly preferably between 20 mbar and 250 mbar.

15. Method according to claim 13 or 14, wherein the first sensor (7) and the second sensor (8) measure a pressure, a pressure difference and / or an average of the pressures detected by the first sensor (7) and the second sensor (8) is determined, and the first pressure setting unit (5) and the second pressure setting unit (6) are controlled based on the pressure difference and / or the average.

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