阅读说明：本技术 用于以油墨印刷的设备 (Device for printing with ink ) 是由 J-A·菲舍尔 于 2021-03-01 设计创作，主要内容包括：本发明涉及一种用于以油墨进行印刷的设备,包括用于油墨(2)的存储容器(4)以及包括由多个彼此相同的且产生油墨滴(3)的印刷元件(6)、例如印刷头所构成的组件(5),所述印刷元件由共同的第一管路(10)并行地供应油墨,其特征在于,与所述印刷元件(6)不同的并且关于其油墨流量可控制或可调节的构件(7)、例如泵并行于所述印刷元件由所述第一管路(10)供应油墨(2)。本发明能够以有利的方式实现,最大程度上或者甚至完全降低油墨中的动液和/或静液压力的不希望的变化。(The invention relates to a device for printing with ink, comprising a storage container (4) for ink (2) and an assembly (5) consisting of a plurality of printing elements (6), for example printing heads, identical to one another and generating ink drops (3), which are supplied with ink in parallel by a common first line (10), characterized in that a component (7), for example a pump, which is distinct from the printing elements (6) and controllable or adjustable with respect to its ink flow rate supplies ink (2) in parallel to the printing elements by the first line (10). The invention can be implemented in an advantageous manner, minimizing or even completely reducing undesired variations in the hydrodynamic and/or hydrostatic pressure in the ink.)

1. An apparatus for printing with ink, comprising:

-a storage container (4) for ink (2), and

-an assembly (5) made up of a plurality of printing elements (6) identical to each other and generating ink drops (3), said printing elements being supplied with ink in parallel by a common first duct (10),

it is characterized in that the preparation method is characterized in that,

means (7) distinct from the printing element (6) are provided, said means being controllable or adjustable with respect to the ink flow rate thereof, said means being supplied with ink (2) by the first conduit (10) in parallel with respect to the printing element.

2. The apparatus as set forth in claim 1, wherein,

it is characterized in that the preparation method is characterized in that,

the component (7) is controlled or regulated in a manner complementary to the total ink consumption of the printing element (6) or to the total ink flow through the printing element (6).

3. The apparatus as set forth in claim 2, wherein,

it is characterized in that the preparation method is characterized in that,

the component (7) is controlled or regulated in a compensating manner with reference to the total ink consumption of the printing element (6) or with reference to the total ink flow through the printing element (6).

4. The apparatus according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the apparatus (1) comprises a common second line (20), and

the second line leads to the printing element (6), whereas it leads the unprinted ink (2) back to the storage container (4).

5. The apparatus as set forth in claim 4, wherein,

it is characterized in that the preparation method is characterized in that,

the printing element (6) and the member (7) are connected in parallel to each other between the two conduits (10, 20).

6. The apparatus according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the member (7) is a member (7) different from: a printing nozzle, a set of printing nozzles, a one-dimensional array of printing nozzles, a two-dimensional area of printing nozzles, a printing head, a set of printing heads, or a printing beam, or

The member (7) does not generate ink droplets.

7. The apparatus as set forth in claim 6, wherein,

it is characterized in that the preparation method is characterized in that,

the component (7) is a controllable or adjustable or dynamically adjustable pump (7) or micropump (7), or an assembly (5) of a plurality of such pumps (7) or micropumps (7).

8. The apparatus as set forth in claim 7, wherein,

it is characterized in that the preparation method is characterized in that,

the pump (7) or micropump (7) is a bidirectional pump (7).

9. The apparatus according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

a bypass (8), i.e. a bypass line (8) for the ink (2), is provided in parallel with the component (7).

10. The device according to one of the preceding claims 4 to 9,

it is characterized in that the preparation method is characterized in that,

the first line (10) comprises a feed pump (11), and/or

The second line (20) comprises a return pump (21).

11. The apparatus as set forth in claim 10, wherein,

it is characterized in that the preparation method is characterized in that,

the feed pump (11) comprises a feed regulator (12) for regulating the ink volume flow in the feed and/or

The return pump (12) includes a return regulator (12) for regulating the volume flow of ink during return.

12. The device according to one of the preceding claims 7 to 11,

it is characterized in that the preparation method is characterized in that,

the pump (7) or micropump (7) is a pump (7) of the type: the maximum pump power of the pump is smaller than the maximum pump power of the feed pump (11) and/or the return pump (21).

13. The device according to one of the preceding claims 7 to 12,

it is characterized in that the preparation method is characterized in that,

the pump (7) or micropump (7) is such a pump (7); the pump power of the pump can be changed more rapidly than the pump power of the feed pump (11) and/or the return pump (21).

14. The device according to one of the preceding claims 7 to 13,

it is characterized in that the preparation method is characterized in that,

the pump (7) or the micropump (7) is a pump (7) whose pump power can be controlled or regulated more rapidly than the pump power of the feed forward pump (11) and/or the return pump (21).

15. The device according to one of the preceding claims 4 to 14,

it is characterized in that the preparation method is characterized in that,

the first line (10) or a first ink distributor (13) of the first line comprises a first ink pressure sensor (15), and/or

The second line (20) or a second ink distributor (23) of the second line comprises a second ink pressure sensor (25).

16. The apparatus according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the printing element (6) is the following:

-a printing nozzle (6), or

-at least one set of printing nozzles (6), or

-at least one-dimensional printing nozzle arrangement (6), or

-at least one two-dimensional printing nozzle zone (6), or

-a print head (6) comprising a printing nozzle, or

-a plurality of sets (6) of print heads comprising printing nozzles, or

-a print beam (6) comprising a print head.

17. The apparatus according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the device (1) comprises a computer (50) or a regulator (50) for controlling or regulating the component (7), or

The device (1) is connected to a computer (50) or a controller (50) for controlling or regulating the component (7).

18. The device according to one of the preceding claims 2, 3, 11, 14 or 17 or according to one of the claims referring back to the preceding claims 2, 3, 11, 14 or 17,

it is characterized in that the preparation method is characterized in that,

the control or regulation is carried out in such a way that the meniscus pressure of the ink (2) in at least one respective ink outlet opening (9) of the printing element (6) corresponds to a predetermined value.

Technical Field

The invention relates to a device having the features of the preamble of claim 1.

The invention is in the technical field of the graphic industry and is used in particular in the field of ink printing (ink jet) on flat substrates in an industrial manner (i.e. with high productivity), i.e. extremely fine droplets of liquid ink are applied to a sheet-type, web-type, film-type or label-type printing material, preferably made of paper, cardboard, felt, plastic, metal or composite material, according to an image. The invention here relates in particular to: the sub-fields of liquid ink storage, the sub-fields of the print head which supplies the drops of ink with liquid ink circulation, and the sub-fields of the control/regulation of the hydrostatic (hydro statischen) or hydrodynamic (hydro dynamischen) pressure of the liquid ink.

Background

It is known to cyclically supply ink to the print head of an industrial inkjet printer. The ink supply of such machines generally comprises a storage container for the ink, a feed line for the print head, and a return line leading back to the storage container.

During printing, undesirable changes in the hydrodynamic pressure in the ink can occur, since the ink flow (volume of ink per time unit) is dependent on the image information to be printed and variable in time of the printed image. At the beginning of printing of a printed image (requiring a large amount of ink), the hydrodynamic pressure in the ink drops strongly and at the end rises strongly. Thus, the preset hydrostatic pressure (so-called meniscus pressure) in the ink may be undesirably changed.

The hydrostatic pressure can be set by the height arrangement of the involved components and/or by the arrangement of the involved circulation pumps in the feed line and the return line.

This change is undesirable because ink may escape from the print head uncontrollably, or air may enter the print head; the quality of the printed product produced can be greatly impaired.

Such disturbing variations of the hydrodynamic forces in the ink should therefore be avoided.

One known measure is for example to install a pressure peak damper in the ink circuit. Another measure is the regulation or pre-control of the pump line of the circulation pump. However, these measures are often inadequate, for example the circulation pump cannot usually be adjusted quickly enough.

Disclosure of Invention

The object of the present invention is therefore to provide an improved solution in relation to the prior art, which in particular makes it possible to minimize or even completely reduce undesirable changes in the hydrodynamic and/or hydrostatic pressure (hydrostatic drive) in the ink.

According to the invention, this object is achieved by a device according to claim 1.

Advantageous and therefore preferred embodiments of the invention emerge from the dependent claims and from the description and the drawings.

The invention relates to a device for printing with ink, comprising a reservoir for ink and an assembly (Anordnung) of a plurality of printing elements that are identical to one another and produce ink drops, said printing elements being supplied with ink in parallel by a common first line, characterized in that a component that is different from the printing elements and is controllable or adjustable with respect to its ink flow rate is supplied with ink in parallel to the printing elements by the first line.

The invention advantageously makes it possible to minimize or even completely reduce undesirable variations in the hydrodynamic and/or hydrostatic pressure in the ink.

In addition to the above-described printing elements (e.g. print heads), the invention advantageously uses a further component. This further component is different from the printing element described above, i.e. not a print head, but a pump, for example; furthermore, the further member is controllable or adjustable with respect to its ink flow rate, e.g. the pump power (ink volume per time unit) can be controlled or adjusted; and the other member is supplied with ink parallel to the printing element, for example the pump may be connected to the same conduit or to the same ink dispenser of the conduit.

Undesirable (because of interfering) pressure fluctuations or pressure peaks can be reduced or compensated to a maximum extent or even completely. For this purpose, the component can be controlled or regulated (in particular in a compensating manner). The above-described control or regulation can advantageously be carried out in addition to the control or regulation of possible circulation pumps in the ink feed and/or ink return (i.e. in a possible ink circuit).

This component can be controlled or adjustably designed in an advantageous manner more quickly than another pump (for example a feed pump or a return pump). As a result, the component can reduce or compensate for undesirable (because of interfering) pressure fluctuations or pressure peaks more quickly to the maximum or even completely.

The component can advantageously be controlled or regulated in a phase-reversed manner (gegenphasig), complementary and/or compensated manner relative to the printing element. When these printing elements print more/less ink, then less/more ink may flow through the member, for example, a pump may be used as the member to deliver less/more ink. Thus, the component may be considered as a type of "Dummy" (Dummy) printing element, for example a "Dummy" print head or a "Dummy" printing nozzle inside a print head.

This means preferably produces a volume flow (volume of ink per time unit) which can be changed fast enough (compared to the volume flow of the printing element to be compensated) and which is continuously complementary in this way. Preferably, the compensation is performed substantially in real time.

A simple embodiment of the invention preferably comprises two larger (higher pump power and/or higher delivery volume) and slower (time constant Tau: 40ms to 100ms) pumps for feed/return and in comparison smaller (lower pump power and/or lower delivery volume) and faster (time constant Tau: < 10ms) pumps for compensation. The compensation pump preferably operates at a lower rotational speed than the circulation pump, i.e. it changes its operating point to a lower rotational speed level, whereas the circulation pump changes its operating point to a higher rotational speed level.

The preferred embodiment of the invention (extension) is described below.

An embodiment can be characterized in that the component is controlled or regulated in a manner complementary to the total ink consumption of the printing elements or to the total ink flow through the printing elements.

A further development can be characterized in that the component is controlled or regulated in a manner complementary to the total ink consumption of the printing elements with reference to a predefined ink flow rate of the device.

A further development can be characterized in that the component is controlled or regulated in a manner complementary to the total ink flow through the printing elements with reference to a predefined total ink flow of the device.

An embodiment can be characterized in that the component is controlled or regulated with reference to the total ink consumption of the printing elements or with reference to the total ink flow through the printing elements.

In a further development, the device comprises a common second line which leads to the printing elements and then leads the unprinted ink back to the storage container.

A further development can be characterized by the fact that the ink circulates in a system in which: the system includes at least a storage vessel, a first conduit, a printing element, and a second conduit.

An embodiment can be characterized in that the printing elements and the component are connected in parallel to one another between the two lines.

A further embodiment can be characterized in that the printing elements and the component are connected parallel to one another in such a way that the connection points for feeding ink into the printing elements follow one another on a first line and the connection points for returning ink from the printing elements follow one another on a second line.

A further development can be characterized in that the connecting points for the component are arranged downstream of the connecting points for the printing elements in the direction of flow of the ink.

A further development can be characterized by the fact that a bypass (i.e. a bypass line for the ink) is present between the two lines.

A further embodiment can be characterized in that the connection point for the component is connected to a bypass.

An embodiment can be characterized in that the component is a different component from the following: a print nozzle, a set of print nozzles, a one-dimensional array of print nozzles, a two-dimensional print nozzle area, a print head, a set of print heads, or a print beam, or the member does not produce ink droplets.

An embodiment can be characterized in that the component is a controllable or adjustable or dynamically adjustable pump or micropump or an assembly of a plurality of such pumps or micropumps.

Preferably, such a pump or micropump produces only a compensating ink volume flow, but no ink circulation flow. Thus, such a pump or micropump can be designed or reduced "less" with respect to its pump power, compared to a circulation pump (feed forward pump and/or return pump).

Such a pump or micropump is preferably attached tightly (with a shorter line compared to the feed line and/or return line) or even directly to the ink dispenser of the feed line to the printing element.

Such a pump may be a pump that acts as a pushing action or a pumping action (with respect to the flow direction of the ink in the ink circuit and/or with respect to the connection point of the ink circuit).

An embodiment can be characterized in that the pump or micropump is a bidirectional pump (bidirectional pump).

A further development can be characterized in that the pump or micropump is a hose pump or a gear pump.

An embodiment can be characterized in that a Bypass (Bypass) is provided parallel to the component, i.e. a Bypass line for the ink.

A further embodiment can be characterized in that the pump or the micropump pumps the ink back into the storage container.

A further development can be characterized in that the pump or micropump pumps the ink back into the storage container via a third line.

An embodiment can be characterized in that the first line comprises a feed pump (Vorlaufpumpe) and/or the second line comprises a return pump (rucklaufpumpe).

An embodiment can be characterized in that the feed pump comprises a feed regulator (vorlaufreegler) for regulating the ink volume flow in the feed and/or the return pump comprises a return regulator (rucklaufreegler) for regulating the ink volume flow in the return.

In one embodiment, the pump or micropump is a pump: the maximum pump power of the pump is less than the maximum pump power of the feed pump and/or the return pump.

In one embodiment, the pump or micropump is a pump: the pump power of the pump may be changed more quickly than the pump power of the feed pump and/or the return pump.

In one embodiment, the pump or micropump is a pump: the pump power of the pump can be controlled or regulated more quickly than the pump power of the feed pump and/or the return pump, in particular 5 times to 10 times as fast or 50 times to 100 times as fast.

A further development can be characterized in that the first line comprises a first ink distributor for the printing element and/or the second line comprises a second ink distributor for the printing element.

In a further development, the first line or the first ink dispenser comprises a first ink pressure sensor and/or the second line or the second ink dispenser comprises a second ink pressure sensor.

In one embodiment, the printing element can be characterized in that it comprises the following components: a print nozzle, or at least one set of print nozzles, or at least one-dimensional array of print nozzles, or at least one two-dimensional print nozzle zone, or a print head comprising print nozzles, or a set of print heads comprising print nozzles, or a print beam comprising a print head.

This component (e.g. a pump or a micro-pump) may be integrated into the print beam, e.g. similar to another print head.

The invention can be implemented using printing nozzles or at least one set of printing nozzles or at least one-dimensional printing nozzle arrangement or at least one two-dimensional printing nozzle zone as printing elements in that at least one printing head is provided with printing nozzles according to the invention or with the mentioned alternatives. This solution is preferably implemented by the manufacturer of the print head. The solution with a print head comprising printing nozzles or a set of print heads comprising printing nozzles or a printing beam comprising a print head as printing element according to the invention is preferably implemented by the machine manufacturer of the graphics industry and the print heads or the mentioned alternatives are integrated into the machine here.

The embodiment according to the invention of an additional printing nozzle (compensation nozzle) as the component parallel to each printing nozzle can be realized in that the additional printing nozzle is controlled by means of an inverted control signal (invertsen stepersignal) compared to the associated printing nozzle. Such compensation may then be optimal.

If a plurality of printing nozzles are compensated in combination, that control signal for the compensating nozzle can be weighted by the image information to be printed. Furthermore, such compensation nozzles can be larger than the printing nozzles to be compensated, i.e. for example, more ink is ejected, so that the compensation can be summed over all printing nozzles.

Instead of using the printing nozzle as a compensating component, it is also possible to provide a line: the conduit has a valve that is controllable similarly to the printing nozzle. Such a conduit preferably directs ink back into the ink circuit. In this way, it is not necessary to actually eject ink for compensation.

If larger units are compensated (i.e. for example a set of printing nozzles, or at least one-dimensional array of printing nozzles, or at least one two-dimensional area of printing nozzles, or a printing head comprising printing nozzles, or a plurality of sets of printing heads comprising printing nozzles, or a printing beam comprising a printing head), the components that play a role in the compensation (for example a pump) are dimensioned correspondingly larger.

A further development can be characterized in that the device comprises an ink heater and/or an ink deaerator. Additionally, a filter and/or a device for charging the ink can also be provided.

A further development can be characterized in that the first ink pressure sensor is connected to the feed regulator and/or the second ink pressure sensor is connected to the return regulator.

A further embodiment can be characterized in that the device comprises or is connected to a computer or a controller which controls or regulates the component.

A further development can be characterized in that the first ink pressure sensor and/or the second ink pressure sensor is connected to the computer or the controller.

A further development can be characterized in that the computer or the controller controls or controls the feed pump and/or the return pump, or that the computer or the controller is connected to the feed controller for the feed pump and/or the return controller for the return pump.

A further development can be characterized in that a feed line is present between the pump or micropump and its corresponding connection point.

A further development can be characterized in that the pressure of the ink in the supply line is measured by means of an ink pressure sensor connected to the computer or the controller or by means of two ink pressure sensors connected to the computer or the controller.

A further development can be characterized in that the control or regulation is carried out in such a way that the meniscus pressure (meniskusdrive) of the ink in at least one respective ink outlet opening of the printing elements corresponds to a predefined value.

The features and feature combinations (in any combination with one another) disclosed in the technical field, inventive content and developments of the above paragraphs and in the examples of the following paragraphs are further advantageous developments of the invention.

Drawings

Fig. 1 to 5 show preferred embodiments and further embodiments of the invention. Features that correspond to each other are provided with the same reference numerals in the figures. For the sake of clarity, reference numerals that are repeated in the drawings are partially omitted.

Detailed Description

Fig. 1 shows a preferred embodiment of the device according to the invention.

The device 1 according to the invention is preferably used for supplying ink 2 to an ink printer for producing ink droplets 3 in accordance with a printed image.

The device 1 comprises a storage container 4 for storing ink 2, and an assembly 5 of a plurality of printing elements 6, which in this example are configured as print heads 6, for ejecting ink droplets 3 from ink discharge openings 9, preferably from individually controllable nozzles. These print heads can be arranged in an array, for example, and form a print beam.

The device 1 comprises a member 7, in this example the member 7 is configured as a pump 7.

The device 1 comprises a first line 10, the first line 10 having a feed pump 11, the feed pump 11 being used to convey the ink 2 from the storage container 4 to the printing element 6. The first line 10 comprises a first ink distributor 13 for distributing the ink 2 in parallel to the printing elements 6 (or to the connection points 14 of the printing elements 6).

The apparatus 1 comprises a second line 20, said second line 20 having a return pump 21, said return pump 21 being used to transport unprinted ink 2 from these printing elements 6 back to the storage container 4. The second line 20 comprises a second ink distributor 23, which second ink distributor 23 has a connection 24 for the printing element 6.

The apparatus 1 comprises a third line 30, which third line 30 has a feed line 31 (or a fourth line) leading to the component 7. The third line 30 is connected to the first line 10 and preferably to the ink distributor 13 of this first line 10 and preferably leads back to the storage container 4.

The member 7 is connected in parallel to the printing elements 6 and is supplied with ink 2 in parallel to the printing elements 6.

The device 1 comprises a (digital) computer 50. The computer 50 preferably controls or regulates the component 7 (i.e. for example the pump 7). This type of control or regulation is described in detail in the other embodiments of fig. 2 to 4. In the example of fig. 1, the computer 50 actuates the component 7 (i.e. for example a pump) in such a way that the ink flow rate through the component 7 is preferably substantially complementary to the ink flow rate through the printing elements 6 (i.e. preferably to the total printing ink volume). In other words: when these printing elements 6 print a large quantity of ink 2, then correspondingly little ink 2 flows through the component 7; when these printing elements 6 print little ink 2, then correspondingly much ink 2 flows through the member 7. The complementary ink volumes are preferably determined such that the ink volumes delivered by the pumps 11 and 21 do not need to be changed or need to be changed only slightly in order to avoid interfering pressure peaks or pressure fluctuations in the hydrodynamic pressure of the ink.

Fig. 1 also shows a (circulation) system 40 and a flow direction 60 of the ink in the system 40 and a print substrate 70 for manufacturing a printed product to be printed with ink droplets 3, the system 40 comprising at least: a storage container 4, a first conduit 10, a printing element 6 and a second conduit 20.

Fig. 2 shows another preferred embodiment of the device according to the invention.

The illustrated device 1 comprises all the features illustrated in fig. 1 and others described below.

The apparatus 1 comprises in the first ink line, for example, an ink heater 34 and, for example, an ink deaerator 35 and, for example, further components (for example, valves). In the first circuit 10, these components are shown generally as hydraulic impedances 80.

The device 1 comprises a first pressure sensor 15 and a second pressure sensor 25. The first pressure sensor 15 is preferably arranged on the first ink dispenser 13. A second pressure sensor 25 is preferably provided on the second ink dispenser 23.

The apparatus 1 comprises a feed-forward regulator 12 and a return-feed regulator 22. The input end of the feed forward regulator 12 is connected with a first pressure sensor 15; and the output is connected to the feed forward pump 11. The input of the foldback regulator 22 is connected to a second pressure sensor 25; and the output is connected to the return pump 21.

The first pressure sensor 15 measures pressure P _1 and the second pressure sensor 25 measures pressure P _ 2. These measured values are transmitted as actual values to the regulators 12 and 22. The feed regulator 12 and the return regulator 22 regulate the ink pressure in the ink cycle. Preferably, the setpoint values of the regulators are predefined such that an acceptable meniscus pressure is formed on the printing elements 6, i.e. such that no ink can escape in an uncontrolled manner and no air can enter.

In this state (when not printing), it is preferable to form a volume flow of ink flowing in and a volume flow of ink flowing out which are identical in their value.

When these printing elements 6 print, ink (in the form of ink droplets 3 or a corresponding printing volume flow) is extracted from the system 40. If the present invention is not employed. Printing the volume flow 3 may correspondingly increase the volume flow in the line 10 and correspondingly decrease the volume flow in the line 20.

The figure shows exemplary further hydraulic resistances 81, 82 and 83. These hydraulic impedances 81, 82 and 83 should be present as corresponding hydraulic impedances of the above-mentioned lines.

The hydraulic impedances 81 and 82 form a hydraulic grade divider (hydraulischen druckpegeltailer) which can simulate the meniscus pressure of the printing elements 6. A preferably complementary printing volume flow (with respect to the printing volume flow via the printing elements 6) is generated by means of the component 7 from the exit point between these two impedances.

The magnitude of this complementary printing volume flow corresponds in the inoperative state (i.e. when not printing) to the maximum printing volume flow via the printing elements 6. This flow can be measured as a pressure drop over the hydraulic resistance 83 and can be set by means of the member 7. This ink fraction is preferably returned to the storage tank 4 via a third line 30.

During printing, the printing volume flow through these printing elements 6 increases. Here, the meniscus pressure can undesirably vary strongly if the present invention is not used. Slight changes that have occurred can be registered by these sensors 15 and 25 (or 32). The computer/regulator 50 preferably actuates the component 7 in such a way that the complementary printing volume flow (ink flow) is reduced. In this case, the regulator 50 (as a compensation regulator) regulates two values: i.e. to regulate the complementary printing volume flow in the inoperative state (Ruhezustand) and during printing. The regulator 50 is designed such that the regulator 50 initially stabilizes the meniscus and, when the meniscus is stabilized (deviation is zero), adjusts the complementary printing volume flows to their predefined target values (maximum values).

Fig. 3 shows another preferred embodiment of the device according to the invention.

The illustrated device 1 comprises all the features illustrated in fig. 1 and others described below.

This embodiment is preferred in practice with respect to the embodiment of fig. 2.

The complementary printing volume flows (ink flow rates) are generated in total by two components connected in parallel to one another: a hydraulic resistance 83 (e.g. a bypass 33, such as an ink line) and a bidirectional member 7 (e.g. a pump 7) which can generate a printing volume flow in one direction or in the other.

The hydraulic resistance 83 is dimensioned such that preferably substantially half of the maximum printing volume flow flows through the hydraulic resistance 83.

The component 7 can contribute a positive or negative component of the volume flow. Such a complementary printing volume flow can therefore be combined from partial flows of two components connected in parallel to one another, and can always assume either a zero value or a (predefined) value of the maximum printing volume flow.

The regulator 50 uses the measurements of these sensors 15 and 25 for calculating the meniscus pressure, and the regulator 50 regulates the member 7. In the case of a meniscus pressure deviation, the regulator 50 regulates the component 7 accordingly.

Examples of values are given below by way of example:

a circulating volumetric flow (in the case of the deactivated component 7 and the deactivated hydraulic resistance 83) of 800 ml/min;

printing volume flow (sum of these printing elements 6) 400 ml/min;

a circulating volume flow (in the case of an active hydraulic resistance 83) of 800ml/min +200ml/min of 1000 ml/min;

a supplementary printing volume flow or ink flow (sum of the components 7 activated and the hydraulic resistances 83 activated) of 400 ml/min;

complementary printing volume flows (via activated hydraulic resistance 83) of 200 ml/min;

when printing, the complementary printing volume flow (via activated member 7) is +200mL/min, and when not printing, the complementary printing volume flow is-200 mL/min.

Fig. 4 shows a preferred embodiment of the device according to the invention.

The illustrated device 1 comprises all the features shown in fig. 1 and others described below.

This embodiment is preferred in practice compared to the embodiment of fig. 2 and 3. In practice, the hydraulic resistance 83 (connected in parallel) may be dispensed with and the bidirectional member 7 may operate "alone" (i.e. without the hydraulic resistance 83 connected in parallel or without the bypass 33).

The regulator 50 (as a compensation regulator) can process the respective measured values of the two sensors 15 and 25 into actual values for the meniscus pressure on the printing elements 6. The regulator 50 can take into account, in particular, the geodetic height between the ink dispensers 13 and 23 and the ink outlet openings 9 of the printing elements 6

For example, the difference between a predefined setpoint value of the meniscus pressure on the printing elements 6 and the actual value of the meniscus pressure on the printing elements 6 can be fed to the regulator 50 (preferably as a proportional regulator). The regulator 50 can regulate the ink flow (e.g. the pump power of the member 7) based on these values.

The feed-forward regulator 12 and the return-feed regulator 22 are preferably set such that they also regulate the meniscus pressure on these printing elements 6, but significantly slower than the regulator 50. The respective technical solution according to fig. 2 or fig. 3 is thereby advantageously converted from a purely complementary compensation of the printing volume flow into a dynamic complementary compensation of the printing volume flow.

In this case, the printing volume flow via the printing elements 6 is preferably compensated for instantaneously (or in real time) by the complementary printing volume flow (ink flow) via the component 7. The regulator 50 by means of the member 7 is fast in its reaction (compared to the regulators 12 and 22 by means of the pumps 11 and 21).

Examples of values are given below by way of example:

- ("slow") circulation pumps 11 and 21: the time constant Tau is 100 ms;

- ("fast") compensation pump 7: the time constant Taus is 1 ms;

-a circulating volumetric flow (in the case of non-activated member 7) of 900ml/min (or 15 ml/s);

printing volume flow (via the sum of the printing elements 6) of 600ml/min (or 10 ml/s);

-the printing elements are printed for 10 seconds;

-the printing element does not print for 20 seconds;

-complementary printing volume flows or ink flow rates +/-300ml/min (or +/-6 ml/s);

the ink supply system takes about 10 to 20 seconds to reach the working point;

about 60ml/min through the bypass.

Fig. 5 shows a diagram.

The diagram 90 shows the course of two curves 91 and 92. The abscissa gives the time t (e.g. in ms) and the ordinate gives the volume flow (e.g. in m)³In units of/s).

The curve 91 corresponds to the ink volume flow in the first ink dispenser 13 (the so-called "feed" flow supplied to the printing elements 6) and shows a significant increase after the initial shaking phase (for example in a time period between 30ms and 40ms or between 60ms and 70 ms). These periods correspond to the printing phase.

Curve 92 corresponds to a complementary volume flow or ink flow rate (or: compensation volume flow) through component 7. This complementary volume flow shows the time profile: so that the sum of the "feed" flow and the compensation volume flow has a substantially constant course.

List of reference numerals

1 apparatus

2 ink/printing volume flow

3 ink drops

4 storage container

5 Assembly

6 printing elements, e.g. print heads

7 members, e.g. pumps

8 bypass

9 ink discharge opening

10 first pipeline

11 front feeding pump

12 feed forward regulator

13 first ink distributor

14 attachment site

15 first ink pressure sensor

20 second pipeline

21 return pump

22 return regulator

23 second ink Dispenser

24 attachment site

25 second ink pressure sensor

30 third pipeline

31 supply line or fourth line

32 ink pressure sensor

33 bypass

34 ink heater

35 printing ink deaerator

40 System

50 computer or regulator

60 direction of flow

70 printing material

80-83 Hydraulic impedance (hydraulischer Widerstand)

90 diagram

91 first curve

92 second curve