DE102014217795A1 - Printing device and a method for applying a coating agent on at least one substrate - Google Patents

Abstract

The invention relates to a printing device which has at least one ink jet print head, wherein the printing device has at least one suction device and wherein at least one nozzle for ejecting exclusively at least one fluid other than the coating agent is arranged, and a method for applying a coating agent to at least one printing material by means of at least one Inkjet printhead of a printing device, and wherein coating agent drops are applied to the at least one substrate and wherein in a contact region of the printing device upon impact of the coating agent drops on the at least one substrate a coating agent mist is formed and wherein at least one nozzle orifice of at least one nozzle exclusively at least one fluid is ejected and wherein the coating agent mist is sucked off by means of at least one suction device.

Description

The invention relates to a printing device according to the preamble of claim 1 and a method for applying a coating agent to at least one printing substrate.

Printing devices, such as ink jet printing devices, especially continuous ink jet printing devices, have been used industrially for many years for marking a variety of products. An underlying principle of operation consists, for example, in that a coating material to be printed, for example an ink from a reservoir, is conveyed via pumps with overpressure into a pressure chamber in the actual print head which has a print head nozzle. The printhead nozzle has, for example, an opening diameter in the range of 30 microns to 200 microns. For a continuous ink jet printing device, a jet of coating material first emerges from the printhead nozzle as a continuous stream, which is impractical for a label since, for example, characters to be generated are preferably composed of individual dots or individual coating agent drops. In order to separate the jet into individual homogeneous coating agent droplets and thus into a jet of coating agent droplets, a modulating element is preferably attached to the pressure chamber which generates pressure fluctuations in the outgoing jet so that it breaks up into individual similar coating agent droplets after exiting the printhead nozzle ,

Shortly before the tearing off of the coating agent drops, they are preferably provided with an individual electrical charge or not, the height of the charge depending on the desired impact position on the printing material or product to be labeled. To ensure this, the coating agent preferably has a corresponding electrical conductivity. On their initially straightforward flight, the optionally electrically charged coating agent drops preferably enter the electrostatic field of a plate capacitor and, depending on their individual charge, are more or less deflected from their rectilinear motion and optionally fly at a respective charge-dependent angle to theirs after leaving the electrostatic field original trajectory continues. With this principle, different impact positions can be selected on a surface to be labeled with individual coating agent drops, which takes place, for example, only in one deflection direction.

To hide individual drops from the typeface or when not to be printed, the coating agent drops preferably receive a certain charge or remain uncharged, so that they meet after exiting the electrostatic field of the plate capacitor in a collection tube, from where they pumped back, for example, in the ink tank become. Often, the print head has a housing which at least partially encloses the print head nozzle, the plate capacitor and the collection tube and which has a housing opening of the print head, through which the drops provided for coating a printing material can emerge.

For example, at high printing speeds, it may happen because of corresponding short distances between the individual coating agent droplets, that coating agent drops hit at locations on a substrate on which coating agent has already been applied, which, however, has not dried sufficiently. As a result, coating agents can be whirled up and form a coating agent mist, which deposits on surfaces located in the environment. As a result, for example, coating agent can build up on the printhead nozzle and / or on the housing opening of the printhead provided for the outlet of coating agent drops, which prevents unhindered escape of coating agent droplets from the printhead nozzle and / or from the printhead and thus to a relatively poor print image or to a complete print image Failure of the printhead can result. As a result, a print job must be interrupted to perform cleaning. This leads to increased costs, on the one hand by downtime of the printing device and on the other hand by resulting wastepaper. In particular, in print jobs such as markings of cables of large lengths, there is a need to be able to perform a complete printing process of a substrate in one piece, without interruptions for cleaning work.

By the EP 0 166 925 A1 For example, a printing device is known that has at least one inkjet printhead. This is used to attach markings to insulated cables.

The invention has for its object to provide a printing device and a method for applying a coating agent on at least one substrate.

The object is achieved by the features of claim 1 and the features of claim 10.

The advantages that can be achieved with the invention are, in particular, that a coating agent mist occurring during a coating process, for example, can be transported away from a region between a print head and a printing substrate, in particular can be sucked off and thus contamination of the print head can be reduced or prevented without adversely affecting a printed image. As a result, at least fewer or no interruptions of a printing process are necessary, so that costs can be kept low, for example, those for waste or caused by machine downtime.

A coating agent mist is to be understood in particular as meaning a plurality of coating agent drops, so-called secondary coating agent drops, which arise in the event of a collision of tropics produced directly by a print head, so-called primary coating agent drops, with the printing substrate and / or with already applied coating agent or other objects. Typically, the coating agent droplet secondary drops in size and mass are significantly smaller than the primary coating agent drops.

Another advantage is that, especially when coating cables, long print jobs, high-quality fast printing and fast substrate transport are made possible, and at most very little waste is produced.

In contrast to a method wherein deposition of dried remnants of coating agent in the printhead nozzle and / or in the housing opening of the printhead is effected by introducing slight overpressure into the printhead and discharging compressed air along with the coating agent drops from a printhead nozzle and / or a housing opening of the printhead is to be prevented in the preferred method, an advantage in particular that, however, the trajectory of the coating agent drops and thus the quality of the pressure is not adversely affected by a gas flow resulting from the pressure.

A further advantage is that the preferred use of a nozzle for at least one fluid other than the coating agent and / or a jet pump does not pose the risk of contaminating or clogging a moving part of a suction pump. Another advantage is that a particularly high explosion protection is possible because it can be dispensed with electrically driven pumps. Thus, even coating agent mist can be removed from such coating compositions containing flammable solvents in a particularly secure manner.

A further advantage is that at least one suction device can be positioned in different positions relative to the at least one print head, for example by slots in the at least one guide element, which allow different attachment positions of fastening screws. As a result, it is possible to respond to particular conditions, for example different substrates. For example, in the case of very narrow printing substrates such as cables or pipes, the suction device can be arranged on a side of the printing material arranged opposite the print head, while an arrangement of the printing head and the suction device can be realized on a same side of the printing substrate in the case of flat, for example sheet-like substrates. Furthermore, for example, a geometric configuration of a region around an inlet opening of a guide element of the suction device to the respective printing substrate and / or respective spatial conditions can be adapted.

Another advantage is that an effect of the suction device is less sensitive to different settings of pressures and / or flow rates of at least one fluid, as would be the case when generating an overpressure in the print head. This is due in particular to the fact that the fluid preferably does not coincide with a jet of coating agent drops before they impact the printing material. Thus, even with relatively coarse deviations from ideal settings of pressure and / or pressure flow rate of the fluid, a high quality when applying the printing material can be achieved. The at least one fluid is preferably a driving fluid.

Another advantage is, for example, that by mixing and turbulence of constituents of a substance mixture to be sucked off, for example of ambient air and coating mist especially within the at least one guide element drying of the coating agent mist forming coating agent drops within the substance mixture to be sucked off and collected these dried coating agent drops as a powder and can be disposed of. This facilitates cleaning, for example because less coating agent sticks to surfaces of the printhead. As an alternative or in addition to the ambient air, at least one inert gas can also be used. At least one collecting device, for example a collecting container or a sponge, is preferably arranged, by means of which the powder, in particular dried to powder, is arranged Coating agent mist collected and can be removed specifically. Alternatively or additionally, the printing device is thus preferably characterized in that at least one collecting device is connected downstream of the at least one guide element.

Suitable coating agents are, in particular, inks or paints of a similar structure. Depending on the composition, printing inks can also be used. Inks and printing inks are preferably solutions or dispersions of at least one colorant in at least one solvent. Suitable solvents include, for example, water and / or organic solvents. Inks preferably have no binder or relatively little binder, while printing inks preferably contain a relatively large amount of binder and more preferably further auxiliaries. Colorants may be pigments and / or dyes, pigments being insoluble in the application medium, while dyes are soluble in the application medium. Nonetheless, colorless paints are also meant below when mention is made of coating compositions and / or inks and / or printing inks. The expressions used in the foregoing and / or below inkjet printhead and / or inkjet printing machine are not intended to exclude the use of other coating materials, which are, for example, paints or printing inks.

The printing device is designed for example as an inkjet printing device and has at least one inkjet print head. The printing device preferably has at least one suction device, in particular at least for excess coating agent and / or coating agent mist. Preferably, at least one nozzle is arranged for ejecting at least one fluid other than the coating agent. Preferably, the at least one nozzle for ejecting only the at least one fluid other than the coating agent is a component of the at least one suction device. The at least one suction device therefore preferably has at least one nozzle for ejecting at least one fluid other than the coating agent, the at least one suction device preferably comprising at least one guide element designed in particular as an elongate hollow body for the common removal of a mixture of at least one coating agent mist consisting in particular of secondary coating agent drops on the one hand and at least parts of the at least one fluid on the other hand. More preferably, not only parts of the at least one fluid are removed, but the entire at least one fluid. In addition to the coating agent mist, preferably at least one ambient gas is removed, for example ambient air and / or at least one protective gas. The coating agent on the one hand and the at least one ambient gas and / or the at least one protective gas on the other hand preferably form the substance mixture to be sucked off. Preferably, the at least one nozzle and the at least one guide element are formed as components of at least one jet pump. The at least one nozzle for ejecting only the at least one fluid other than the coating agent is for example also referred to as a drive nozzle.

At least one intended trajectory is preferably defined by the at least one inkjet printhead for, for example, primary coating agent drops ejected in particular by the at least one printhead. Preferably, any intended trajectory and / or trajectory defined by the at least one inkjet printhead is ejected from the ink droplet head directly, especially primary and / or different from the coating agent mist, especially up to a contact area provided for impinging the coating agent droplets on at least one substrate completely outside a whole by the at least one nozzle and / or the at least one guide element fixed flow path or region of the flow path of the particular driving fluid.

The at least one guide element preferably has at least one inlet opening or suction opening and at least one outlet opening and more preferably at least one cavity extending from the at least one inlet opening or suction opening to the at least one outlet opening. As a result, a flow path is preferably clearly defined. Alternatively or additionally, the printing device is thus preferably characterized in that a flow path defined by the at least one guide element or at least a portion of the entire flow path of a particular internal flow path of the at least one guide element from the at least one inlet opening or suction opening to the at least one outlet opening corresponds to a guide element.

Alternatively or additionally, the printing device is preferably characterized in that a flow path defined by the at least one nozzle or drive nozzle or at least a portion of the entire flow path lies within a spatial region defined by a rotary cone whose tip is located at a nozzle opening of the at least one nozzle and having an opening angle of at least 10 ° and at most 170 ° and the axis in a has mean outflow direction of the at least one nozzle.

Alternatively or additionally, the printing device is preferably characterized in that the at least one nozzle is a component that is structurally and spatially separated from the at least one print head. This results in particular the advantage that the nozzle moves relative to the printhead and can be adjusted in particular in their relative position, for example, to respond to different substrates and / or coating means and / or pressure parameters. Alternatively or additionally, the printing apparatus is preferably characterized in that the at least one nozzle is spaced from a printhead nozzle of the at least one printhead and / or from a housing opening of the at least one printhead provided to the outlet of coating agent drop and / or from an interior of the at least one printhead of at least 8 mm. This results in particular preferably the advantage that influences of primary coating agent drops are largely or preferably completely avoided.

Alternatively or additionally, there is a printing device, in particular inkjet printing device having at least one inkjet printhead, the at least one inkjet printhead with respect to its ejection direction on at least one intended transport path for at least one substrate and / or provided for an impact of coating agent drops on at least one substrate contact area , in particular contact region of the printing device is aligned and wherein the printing device has at least one suction device in particular for excess coating agent and / or coating agent mist and wherein the at least one suction device has at least one, for example formed as an elongated hollow body guide element, the at least one inlet opening or suction opening and at least one outlet opening and preferably at least one of the at least one inlet opening or Ansa Within the at least one guide element, the at least one nozzle or drive nozzle is arranged in particular for ejecting at least one fluid other than the coating agent whose nozzle opening defines a mean outflow direction parallel to at least one component a, in particular, the internal flow path of the guide element runs through the guide element from the at least one inlet opening or suction opening to the at least one outlet opening.

Alternatively or additionally, the printing device is preferably characterized in that the at least one inlet opening or suction opening is aligned at least on the contact area and / or the contact area is arranged within the at least one guide element and preferably within the cavity of the at least one guide element. This results in particular the advantage that an extraction of the coating agent mist can be carried out particularly effectively.

Alternatively or additionally, the printing device is preferably distinguished by the fact that at least one intended trajectory is ejected by the at least one inkjet printhead for, for example, ejected by the at least one printhead, and the at least one inkjet printhead is mounted on at least one intended transport path with respect to its ejection direction at least one printing substrate and / or on the intended for impingement of coating agent drops on the at least one substrate contact area, in particular contact region of the printing device is aligned. Alternatively or additionally, the printing device is preferably characterized in that the contact region includes intersections of the at least one intended trajectory for coating agent drops with the at least one intended transport path for the at least one printing material, for example exclusively those intersections and / or all such intersections.

Alternatively or additionally, the printing apparatus is preferably characterized in that a shortest distance between a printhead nozzle of the at least one printhead and / or a housing opening of the at least one printhead provided for the outlet of coating agent drops and, on the other hand, a transport path of between 0.5 mm provided for the printing substrate and 5 cm, and / or that a shortest distance between a printhead nozzle of the at least one printhead and / or housing opening of the at least one printhead provided to the outlet of coating agent droplet on the one hand and a border of at least one inlet opening or suction opening of the at least one guide element between 0, 3 mm and 3 cm. Alternatively or additionally, the printing device is preferably characterized in that the at least one nozzle is connected to a compressed air source and / or connectable. This results in particular the advantage that a particularly simple and inexpensive extraction is possible.

Alternatively or additionally, the printing device is preferably characterized in that a the border delimiting at least one inlet opening or suction opening extends in three mutually orthogonal directions and / or has at least one partial section which surrounds the transport path provided for the printing substrate and / or the printing substrate from three sides. Alternatively or additionally, the printing device is preferably characterized in that the at least one inlet opening or suction opening on the at least one print head and / or on at least one provided for outlet of coating agent drop housing opening of the at least one print head and / or at least one print head nozzle of the at least one print head and / or that each rectilinear extension of any trajectory provided by the at least one inkjet printhead for, for example, primary coating agent drops ejected beyond the contact region by the at least one printhead passes through the at least one inlet or suction opening of the at least one guide element. This preferably results in particular in the advantage that, adapted to geometric conditions and / or dimensions of the printing substrate, the contact region can be enclosed to a particularly large extent by the at least one guide element and therefore extraction of the coating agent mist can be effected particularly effectively.

A method for applying a coating agent to at least one printing substrate by means of at least one inkjet printhead of a printing device, in particular an inkjet printing device in which preferably the at least one printing material is moved along a transport path of the printing substrate is preferably characterized in that coating agent drops are applied to the at least one printing substrate be and that in a contact region of the printing device at a hitting the coating agent droplets on the at least one printing material, a coating agent mist is formed, for example, consists of secondary coating agent drops. Preferably, only the at least one fluid is expelled from at least one nozzle opening of the at least one nozzle, and the coating agent mist is suctioned off by means of the at least one suction device.

Alternatively or additionally, the method is preferably characterized by the fact that the at least one ejected fluid causes a gas flow which, in addition to the fluid, also has at least parts of a gas or gas mixture located at least temporarily in the contact region and wherein the gas stream entrains the coating agent mist. Alternatively or additionally, the method is preferably characterized in that the coating agent mist is extracted by means of at least one jet pump. Preferably, the at least one jet pump is operated with compressed air as a driving fluid.

Alternatively or additionally, the method is preferably characterized in that in a contact region of the printing device when the coating agent drops on the at least one printing material, a coating agent mist arises, which consists for example of secondary coating agent drops and that at least one of at least one nozzle opening at least one in particular of ink nozzles the at least one inkjet printhead different, also known as a nozzle nozzle exiting, in particular different from the coating fluid causes a gas flow having at least in addition to the fluid parts of at least temporarily located in the contact area gas or gas mixture. The gas or gas mixture contains, for example, ambient air and / or at least one protective gas. Preferably, the gas stream entrains the coating agent mist with it. The transport path of the coating agent mist preferably extends exclusively outside the at least one nozzle. Preferably, an entire flow path of the fluid on the one hand and any trajectory of ejected directly from the ink jet printhead, for example, primary, preferably different from the coating agent mist coating agent drops in particular up to an intended for impact of the coating agent droplets on at least one substrate contact area on the other hand separately to each other. This avoids, for example, that primary coating agent drops are impaired in their trajectory.

Alternatively or additionally, the method is preferably characterized in that, when the coating agent droplets strike the coating agent mist formed by at least one printing substrate, at least one suction device is sucked off by means of at least one tubular or tubular guide element and a gas flow within the at least one tubular guide element is directed through a directed Outlet of at least one particular driving fluid from at least one nozzle opening of the at least one also referred to as a drive nozzle nozzle is generated. The directed outlet is preferably a discharge running parallel to and / or tangent to at least one component of a flow path predetermined by the at least one guide element. Preferably, the method is characterized additionally or in an asterisk fashion in that the at least one nozzle opening of the at least one nozzle runs along an internal flow path of the at least one guide element which in particular passes through the line element is arranged between an inlet opening or suction opening and an outlet opening of the at least one guide element.

Alternatively or additionally, the method is preferably characterized in that the at least one printing material has a first dimension, a second dimension and a third dimension, which are oriented in pairs orthogonal to each other and in that the first dimension is a smallest dimension of the printing material and that the second dimension is a smallest orthogonal to the first dimension oriented dimension of the printing substrate and that the second dimension of the printing material is at most five times the first dimension of the printing substrate. This is the case, for example, in the case of a substrate formed as a cable.

Alternatively or additionally, the method is preferably characterized in that the amount of fluid expelled from the at least one nozzle and / or the pressure prevailing in the at least one nozzle is controlled and / or regulated. Such a control and / or regulation is preferably carried out taking into account signals, in particular control signals, which originate from a machine control of the print head and / or come from a machine control, which also sends signals to the at least one print head. In this way, for example, only a relevant amount of fluid can be expelled whenever it is needed for a gas stream to carry away coating agent mist. During printing breaks, this avoids unnecessary consumption of fluid. Such printing pauses may be present if no substrate is to be printed in general or if, for example, print images are to be applied to the printing material only at certain intervals. For example, in the case of printing on cables, corresponding markings are usually not applied continuously, but at a distance of, for example, a few centimeters or a few decimetres. Preferably, the ejection of fluid is effected offset in time for the ejection of coating agent. As a result, a flow of abzusaugendem mixture is already present despite inertia when coating agent mist arises. Preferably, a valve which can be controlled pneumatically and / or electrically, in particular by the machine control, is arranged in a supply line to the at least one nozzle and / or in the at least one nozzle itself.

An embodiment of the invention is illustrated in the drawing and will be described in more detail below.

Show it:

1 a schematic representation of a section through a printing device with a suction device;

2 a schematic perspective wireframe representation of the suction from 1 ;

3 a schematic perspective view of a view of the suction from 2 ,

A printing device 01 , especially as an inkjet printing device 01 is formed, has at least one inkjet printhead 02 or short printhead 02 on. The at least one inkjet printhead 02 is preferred as at least one of a continuous inkjet printhead 02 designed, in particular as an ink jet print head 02 in which coating agent droplets are continuously produced and, depending on the electrical charge, fed to a collecting container or else out of the printing head 02 be ejected. Alternatively, the at least one printhead 02 at least one drop-on-demand printhead 02 , In the drop-on-demand process, coating agent drops are generated and ejected only upon request. The at least one print head 02 preferably has at least one printhead nozzle. The at least one printhead nozzle is preferably an opening separating a first area from a second area, the first area for storing and / or transporting coating agent within a conduit system of the printhead 02 is provided and / or is used and wherein the second area is provided for free flight of coating agent drops and / or is used. The at least one print head 02 has, for example, at least one housing opening of the print head provided for the outlet of coating agent drops 02 on. The at least one housing opening provided for the outlet of coating agent drops is preferably an opening which forms an interior of the at least one print head 02 connects with an environment. This environment has, for example, a designated transport path for printing material 04 and / or a designated contact area 13 between printing material 04 and coating agent drops.

Preferably, the printing device 01 at least one intended transport path for the at least one printing substrate 04 on. The at least one transport path preferably runs opposite the at least one print head nozzle and / or with respect to the at least one housing opening of the at least one print head provided for the outlet of coating agent drops 02 , It is preferred by the at least one Inkjet printhead 02 at least one intended trajectory 03 especially for the at least one printhead 02 ejected, in particular primary coating agent drops set. The at least one trajectory 03 is, for example, a respective electrical charge of the corresponding coating agent drops and an electrical voltage of a traversed by the coating agent droplets plate capacitor of the at least one printhead 02 established. Associated with a respective one, preferably all of the at least one printhead 02 ejected in particular primary coating agent drops same airspeed and a respective, preferably all of the at least one printhead 02 ejected in particular primary substrate drops same mass and preferably all of the at least one print head 02 ejected in particular primary Bedruckstofftropfen same original ejection direction result from this preferably unique trajectories or trajectories 03 that of the at least one printhead 02 ejected in particular primary printing material drops.

The contact area 13 is preferably one for an impact of the coating agent drops on the at least one printing substrate 04 intended contact area 13 , Preferably, the at least one inkjet printhead 02 with respect to its ejection direction on the at least one intended transport path for the at least one printing substrate 04 and / or to the impact of coating agent drops on at least one printing substrate 04 provided contact area 13 the printing device 01 aligned. Preferably, the contact area comprises 13 Intersections of the at least one intended trajectory 03 for coating agent drops with the at least one intended transport path for the at least one printing substrate 04 , More preferably, the contact area comprises 13 excluding intersections of the at least one intended trajectory 03 for coating agent drops with the at least one intended transport path for the at least one printing substrate 04 and / or includes the contact area 13 all intersections of the at least one intended trajectory 03 for coating agent drops with the at least one intended transport path for the at least one printing substrate 04 , In particular, the contact area 13 no part of the substrate 04 but a through the geometry of the printing device 01 determined, in particular flat space area.

The printing device 01 is preferably used to apply at least one coating agent to the at least one printing substrate 04 , The at least one printing material 04 preferably has a first dimension, a second dimension and a third dimension, which are each oriented in pairs orthogonal to each other. The first dimension is preferably a smallest dimension of the printing material 04 , For example, a first diameter of a cable. The second dimension is preferably a smallest orthogonal to the first dimension oriented dimension of the printing material 04 For example, a second diameter of a cable oriented orthogonal to the first diameter is equal in magnitude to the first diameter in the case of a circular cross-sectional area. The third dimension is preferably orthogonal to both the first dimension and the second dimension of the substrate 04 For example, a length of a cable.

The at least one printing material 04 is for example as at least one strand-shaped substrate 04 educated. Under a strand-shaped substrate 04 is preferably a printing material 04 to understand where the second dimension of the substrate 04 preferably at most ten times, more preferably at most five times and even more preferably at most twice the first dimension of the printing substrate 04 is. More preferably, the second dimension is in the case of a strand-shaped substrate 04 essentially the same size as the first dimension of the substrate 04 , Preferably, the third dimension of the printing material in the case of a strand-shaped printing material 04 at least twenty times the first dimension of the substrate 04 , more preferably at least that Fifty times and even more preferably at least thousand times. For example, the at least one printing material 04 as at least one cable and / or at least one tube and / or at least one tube formed. Preferably, the at least one printing material 04 a diameter and / or a first dimension which is between 0.1 cm and 5 cm, more preferably between 0.2 cm and 3 cm.

Alternatively, the at least one printing material is designed as at least one web-shaped printing material. Under a web-shaped substrate 04 is preferably a printing material 04 to understand where the second dimension of the substrate 04 preferably more than ten times, more preferably at least twenty times and even more preferably at least fifty times the first dimension of the printing substrate 04 is. More preferably, the second dimension is in the case of a web-shaped substrate 04 less than one tenth, more preferably less than one twentieth and even more preferably less than one fiftieth of the third dimension of the substrate 04 , The third dimension of the printing substrate is preferably in the case of a web-shaped printing substrate 04 at least twenty times the first dimension of the substrate 04 , more preferably at least fifty times, and even more preferably at least thousand times. For example, the at least one printing material 04 as at least one paper web or at least one plastic web or plastic film or at least one metal sheet or metal foil formed. Web-shaped substrates are used, for example, in roll-fed printing machines.

Preferably, the printing device 01 at least one suction device 06 in particular at least one suction device 06 for excess coating agent and / or coating agent mist and / or secondary coating agent drops. Preferred primary coating agent drops are those coating agent drops which are directly from the at least one print head 02 , In particular, were ejected from the at least one printhead nozzle and since then exclusively freely and without contact with components of the printing device 01 or a substrate 04 have moved. In particular, primary printing substance drops are preferably those substrate drops which are used to produce image dots on the printing substrate 04 are provided. As secondary coating agent drops, preference is given to those coating agent drops which are not directly from the at least one print head 02 but at a hitting at least one primary coating agent drop on the at least one substrate 04 and / or in particular on a not yet dried pixel on the at least one printing substrate 04 arise. Such fluidized secondary coating agent drops preferably form the coating agent mist. Usually, secondary coating agent drops are significantly smaller in diameter and / or mass than primary coating agent drops.

The at least one suction device 06 preferably has at least one example as a drive nozzle 11 designated nozzle 11 on. The at least one nozzle 11 is preferably a structural and spatial of the at least one print head 02 separate component 12 , The at least one nozzle 11 serves to eject at least one fluid, in particular at least one driving fluid. If in the foregoing and / or below of a fluid is mentioned, it is always to be understood as a driving fluid, unless otherwise indicated. Preferably, the at least one nozzle 11 at least one nozzle 11 for discharging only at least one fluid other than the coating agent. The at least one fluid is in particular to be distinguished from a substance mixture to be sucked off. The at least one fluid is preferably at least one gas or gas mixture, for example air, in particular compressed air. It is also possible to use substances or mixtures other than fluid, for example liquids or vapors. However, especially for cost reasons, compressed air is to be preferred as the fluid. The at least one fluid preferably has within one of the at least one nozzle 11 upstream supply line 17 an overpressure relative to an ambient pressure, in particular one the at least one suction device 06 surrounding ambient pressure. This overpressure is preferably between 0.1 bar and 10 bar, more preferably between 0.5 bar and 5 bar and even more preferably between 1 bar and 2 bar. The at least one nozzle 11 is preferred as at least one tubular nozzle 11 formed, which is further preferably at least partially enclosed by at least one intended flow path for at least one substance to be sucked off. An inner diameter of at least one example, as a drive nozzle 11 designated nozzle 11 is preferably between 0.2 mm and 2.0 mm, more preferably between 0.6 mm and 1.0 mm. The at least one nozzle 11 may alternatively or additionally as at least one annular nozzle 11 be formed, which at least partially encloses at least one intended flow path for at least one substance mixture to be sucked.

The at least one substance mixture to be sucked off is preferably a mixture to be removed from at least one gas and secondary coating agent drops or coating agent mist. The at least one substance mixture to be sucked off preferably comprises at least parts of the coating agent mist. The at least one substance mixture to be sucked off has at least parts of the secondary coating agent drops. The at least one substance mixture to be sucked off preferably has parts of an ambient atmosphere, in particular ambient air and / or at least one protective gas. Preferably, the at least one substance mixture to be sucked off is a mixture of the ambient atmosphere, in particular ambient air and the coating agent mist.

The at least one suction device 06 preferably has at least one guide element 09 on, which is more preferred than at least one guide element 09 for the common removal of a mixture of at least one in particular from secondary coating agent drop existing coating agent mist on the one hand and at least the at least one fluid on the other hand is formed. This is preferably at least one guide element 09 formed as at least one elongated hollow body, for example as at least one tubular guide element 09 and / or as at least one tubular guide element 09 , Under a tubular component is preferably a component to understand, which usually has a length which is greater than its average cross section and / or consists of a relatively stable material. A tubular component is preferably understood to mean a component which usually has a length which is greater than its average cross section and / or which consists of a relatively flexible material.

This preferably has at least one guide element 09 at least one inlet opening 07 on, which also has suction opening 07 is called. This preferably has at least one guide element 09 at least one outlet opening 08 on. More preferably, the at least one guide element 09 at least one of the at least one inlet opening 07 or suction port 07 to the at least one outlet opening 08 extending cavity 14 on. This preferably has the at least one guide element 09 a flow path on. A flow path is, in particular, a delimited volume, which by means of its limitations restricts flow processes occurring therein to certain and preferably a flow path. This flow path preferably extends from the at least one inlet opening 07 or suction port 07 of the at least one guide element 09 to the at least one outlet opening 08 of the at least one guide element 09 , In a preferred rectilinear or linear course of the at least one cavity 14 of the at least one guide element 09 Preferably, the flow path is also rectilinear or linear. In an alternative curved course of the at least one cavity 14 of the at least one guide element 09 the flow path preferably follows the curvature of the at least one cavity 14 of the at least one guide element 09 ,

An intended flow path for the substance mixture to be sucked off is a volume through which the mixture of substances to be sucked off in a proper operation of the at least one suction device 06 moves, in particular at a predetermined average speed and predetermined mean flow direction. The mean velocity is an average over all components of the substance mixture to be sucked off, which takes into account that different molecules can have different speeds at least at times. The mean flow direction is an average over all constituents of the substance mixture to be sucked, which takes into account that different molecules can have different directions of movement at least at times. The at least one intended flow path for the at least one substance mixture to be sucked off preferably extends at least from the at least one inlet opening 07 or suction port 07 to the at least one outlet opening 08 of the at least one guide element 09 and more preferably through the at least one cavity 14 of the at least one guide element 09 ,

An intended flow path for the particular driving fluid is in particular a volume through which the fluid in a proper operation of the at least one suction device 06 moves, in particular at a predetermined average speed and predetermined mean flow direction. The mean velocity is an average over all constituents of the fluid, which takes into account that different molecules can have different velocities at least at times. The mean flow direction is an average over all constituents of the fluid, which takes into account that different molecules can have different directions of movement at least temporarily. The at least one intended flow path for the at least one fluid preferably extends at least from at least one nozzle opening 12 the at least one nozzle 11 starting and preferably passes through at least part of the at least one guide element 09 , in particular by at least a part of the at least one cavity 14 of the at least one guide element 09 and more preferably through the at least one outlet opening 08 of the at least one guide element 09 , In a preferred embodiment, the at least one intended flow path for the at least one fluid bypasses the at least one inlet opening 07 or suction port 07 of the at least one guide element 09 , This is the case in particular if, as preferred within the at least one guide element 09 the at least one nozzle 11 is arranged in particular for ejecting only the at least one fluid other than the coating agent.

Preferably, the nozzle opening sets 12 the at least one nozzle 11 a central outflow direction fixed with at least one component parallel to a the guide element 09 from the at least one inlet opening 07 or suction port 07 to the at least one outlet opening 08 passing through in particular internal flow path of the guide element 09 runs. In the case of a curved course of this flow path, the mean outflow direction preferably has at least one component which is tangential to this flow path at the location of the nozzle opening 12 the at least one nozzle 11 runs.

Preferably, the at least one nozzle 11 and that at least one guiding element 09 formed as components of at least one jet pump. A jet pump is preferably a pump in which the pumping action is generated by the driven and / or ejected fluid, wherein the fluid is preferably formed as a gas or gas mixture. By pulse exchange with the largely defined in its direction of movement driven and / or ejected fluid is the in particular sucked in and / or accelerated and / or set in motion at least one gas or gas mixture containing absorbent mixture and transported away in this way. Preferably, a jet pump itself has no moving components, but only stationary components. The jet pump preferably has the at least one in particular as a drive nozzle 11 designated nozzle 11 , at least one inlet opening 07 or suction port 07 , at least one guiding element 09 and at least one exit opening 08 on. The inlet opening or suction opening 07 is preferably used exclusively for the transport of abzusaugendem mixture. The nozzle 11 is preferably used exclusively for the transport of fluid. The outlet opening 08 is preferably used in particular simultaneous transport of the fluid and the substance mixture to be sucked off. The jet pump and in particular its nozzle 11 For example, it is connected to a compressed air source, wherein the compressed air serves as a fluid, in particular as a driving fluid.

Preferably, any particular provided by the at least one ink jet printhead 02 fixed trajectory 03 from directly from the inkjet printhead 02 ejected, in particular primary and / or different from the coating agent mist coating agent droplets completely outside a whole by the at least one nozzle 11 and / or the at least one guide element 09 fixed area of the flow path of the fluid. This preferably applies in particular up to one for impact of the coating agent drops on at least one printing substrate 04 provided contact area 13 ,

Preferably lies through the at least one nozzle 11 fixed flow path or at least portion of the entire flow path of the at least one fluid and / or the at least one substance mixture to be sucked within a space defined by a rotary cone, the tip of which at a nozzle opening 12 the at least one nozzle 11 and having an opening angle of preferably at least 10 ° and at most 170 °, more preferably at least 15 ° and at most 150 ° and its axis in a mean outflow direction of the at least one nozzle 11 has. A rotary cone is a spatial area that can be described by rotation of a right triangle around one of its two catheters. Its opening angle is twice an angle between a generatrix and the axis of the turntable. Preferably corresponds to a through the at least one guide element 09 fixed flow path or at least portion of the entire flow path of the at least one fluid and / or the at least one substance mixture to be sucked off the at least one guide element 09 from the at least one inlet opening 07 or suction port 07 to the at least one outlet opening 08 passing, in particular internal flow path of the at least one guide element 09 ,

Preferably, the at least one nozzle 11 from the at least one printhead nozzle of the at least one printhead 02 and / or from a housing opening of the at least one print head provided for the outlet of coating agent drops 02 and / or from an interior of the at least one print head 02 a distance of at least 8 mm.

In particular, in order to be able to ensure optimum removal of the coating agent mist, it is preferable for the coating agent drops to strike at least one printing substrate 04 provided contact area 13 so relative to the entrance opening 07 or suction port 07 arranged that one in this entrance opening 07 or suction port 07 flowing substance mixture to be sucked off not only consists of ambient air and / or protective gas, but also entrains as large amounts of the coating agent mist as possible. For this purpose, the at least one inlet opening is preferred 07 or suction port 07 at least on the contact area 13 aligned and / or is preferably the contact area 13 within the at least one guide element 09 arranged, more preferably within the cavity 14 of the at least one guide element 09 , In particular, for example, depending on a shape of the at least one inlet opening 07 or suction port 07 bordering different shapes possible, the overall a more or less flowing transition between a pure orientation of the inlet opening 07 or suction port 07 at least on the contact area 13 on the one hand and a pure arrangement of the contact area 13 within the at least one guide element 09 represent. For example, one extends the at least one inlet opening 07 or suction port 07 delimiting border in three mutually orthogonal directions and / or has the at least one inlet opening 07 or suction port 07 delimiting border on at least a section on which the for the substrate 04 provided transport path and / or the substrate 04 surrounded by three sides. For example, the at least one border is formed as a closed line, which is formed substantially planar and at least one or preferably two recesses 16 has, in particular U-shaped recesses 16 which extends with at least one component parallel to a surface normal of the plane containing the rest of the border. Such a particular U-shaped recess preferably represents the said section.

For example, the border apart from the U-shaped recesses 16 essentially the shape of a rectangle. For example, a first side length of this rectangle is between 5 mm and 30 mm, preferably between 10 mm and 20 mm. For example, a second side length of this rectangle is between 10 mm and 50 mm, preferably between 20 mm and 30 mm. Depending on the geometric conditions, the physical properties of the coating agent and the transport speed of the printing substrate 04 other dimensions possible. However, the border may also have other forms, in particular, apart from possibly existing recesses and be formed, for example, as a circle or as an oval or as a square. Inner dimensions of the at least one guide element 09 preferably correspond substantially, ie with a tolerance of beispielswiese not more than 10% of the dimensions of the border of the at least one inlet opening 07 or suction port 07 ,

Preferably, the at least one inlet opening 07 or suction port 07 on the at least one print head 02 and / or at least one housing opening of the at least one print head provided for the outlet of coating agent drops 02 and / or at least one printhead nozzle of the at least one printhead 02 aligned. Preferably, at least one and more preferably each rectilinear extension of each passes through the at least one ink jet printhead 02 intended trajectory 03 especially for the at least one printhead 02 ejected, for example, primary coating agent drops beyond the contact area through the at least one inlet opening 07 or suction port 07 of the at least one guide element 09 ,

For example, one is on a surface of the entrance opening 07 or suction port 07 relative center of gravity relative to the at least one provided to the outlet of coating agent drop housing opening of the at least one print head 02 arranged offset, in particular with a direction parallel to a designated transport direction of the printing substrate 04 , In this way, the fact is preferably taken into account that ambient air and thereby also coating agent mist optionally with the moving substrate 04 being carried away.

A shortest distance between the printhead nozzle of the at least one printhead 02 and / or a housing opening of the at least one print head provided for the outlet of coating agent drops 02 on the one hand and for the substrate 04 provided transport route on the other hand is preferably between 0.5 mm and 5 cm, more preferably between 1 mm and 1 cm and even more preferably between 3 mm and 7 mm. The transport path of the printing substrate preferably proceeds 04 through two U-shaped recesses 16 of the at least one guide element 09 and more preferably such that not the U-shaped recesses 16 belonging parts of the border of the at least one inlet opening 07 or suction port 07 the housing of the printhead 02 are closer than the substrate 04 itself. This will make the contact area 13 particularly well shielded from the environment and there are particularly advantageous flow conditions with respect to the substance to be sucked mixture belonging gas or gas mixture, in particular the ambient air and / or the protective gas. A shortest distance, measured in the intended direction of flight of the primary coating agent drops, between the print head nozzle of the at least one print head 02 and / or a housing opening of the at least one print head provided for the outlet of coating agent drops 02 on the one hand and the border of the at least one inlet opening 07 or suction port 07 of the at least one guide element 09 On the other hand, it is preferably between 0.3 mm and 3 cm, more preferably between 1 mm and 1 cm and even more preferably between 2 mm and 5 mm. A largest dimension of the at least one in particular U-shaped recess 16 depends preferably on the dimensions of the substrate to be printed 04 and is for example between 5 mm and 25 mm, preferably between 8 mm and 12 mm.

This preferably has at least one guide element 09 at least one example slot-shaped mounting opening 18 on, the attachment of the guide element 09 serves. Due to the elongated shape of the at least attachment opening 18 can the guide element 09 at different distances to the print head 02 to be assembled. The at least one attachment opening 18 is preferred before starting the suction device 06 closed, for example by a surface on which the at least one guide element 09 is attached. Preferably, this surface has corresponding threaded bores into which fastening means, for example screws, are screwed, which screw the at least one fastening opening 18 penetrate. For example, with respect to the at least one attachment opening 18 at least one mounting hole 19 arranged, which serves to allow access to the at least one fastening means, for example the at least one screw. Also, the at least one mounting hole 19 is preferred prior to commissioning of the at least one suction device 06 closed, for example by means of at least one lid.

For example, by means of the described printing device 01 , especially The inkjet printing apparatus 01 can be a method for applying a coating agent to a substrate 04 by means of at least one inkjet printhead 02 this printing device 01 carry out. Preference is given to the substrate 04 along the transport path of the at least one printing substrate 04 emotional. In this case, coating agent drops on the at least one printing substrate are preferred 04 applied. Preferably arises in the contact area 13 the printing device 01 upon impact of the coating agent drops on the at least one printing substrate 04 a coating agent mist, in particular a coating agent mist, which consists of secondary coating agent drops.

Preferably, the coating agent mist is sucked by means of the jet pump. Preferably, at least one causes at least one nozzle opening 12 at least one in particular of printhead nozzles of the at least one inkjet printhead 02 different, in particular as a drive nozzle 11 designated nozzle 11 emerging, in particular from the coating agent different fluid a gas stream. In addition to the fluid, the gas stream preferably also has at least parts of it at least temporarily in the contact region 13 located gas or gas mixture. This gas or gas mixture is preferably ambient air and / or an inert gas. The gas stream preferably entrains the coating agent mist with it. The transport path of the coating agent mist preferably extends exclusively outside the at least one nozzle 11 , This will cause contamination of this nozzle 11 prevented by the coating agent mist. Preferably, an entire flow path of the fluid on the one hand and any trajectory of directly from the ink jet printhead 02 on the other hand separately ejected, in particular primary and / or different from the coating agent mist coating agent drops. Separately here means, in particular, free of discrimination.

Preference is given to the impact of the coating agent drops on the substrate 04 resulting coating agent mist by means of at least one example meadow tubular or tubular guide element 09 the at least one suction device 06 aspirated. The gas flow within the at least one tubular guide element is preferred 09 by a directed exit of the at least one fluid from the at least one nozzle opening 12 the at least one nozzle 11 generated. In this case, the at least one nozzle opening is preferred 12 the at least one nozzle 11 along the preferred the conduit element 09 passing through the internal flow path of the at least one guide element 09 between the at least one inlet opening 07 or suction port 07 and the at least one outlet opening 08 of the at least one guide element 09 arranged.

LIST OF REFERENCE NUMBERS

01

 Printing device, inkjet printing device

02

 Printhead, inkjet printhead

03

 trajectory

04

 substrate

05

06

 suction

07

 Inlet opening, suction opening

08

 outlet opening

09

 vane

10

11

 Nozzle, drive nozzle, component

12

Nozzle opening ( 11 )

13

 contact area

14

Cavity ( 09 )

15

16

 recess

17

 supply

18

 fastening opening

19

 mounting hole

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0166925 A1 [0006]

Claims (15)

Printing device ( 01 ), the printing device ( 01 ) at least one inkjet printhead ( 02 ), characterized in that the printing device ( 01 ) at least one suction device ( 06 ) and that at least one nozzle ( 11 ) is arranged for ejecting exclusively at least one fluid other than the coating agent. Printing device according to claim 1, characterized in that the at least one nozzle ( 11 ) for ejecting exclusively at least one fluid that is different from the coating agent is a component of the at least one suction device ( 06 ). Printing device according to claim 1 and / or 2, characterized in that the at least one suction device ( 06 ) at least one guiding element ( 09 ) for the common removal of a mixture of at least one coating agent mist on the one hand and at least parts of the at least one fluid on the other hand. Printing device according to claim 1 and / or 2 and / or 3, characterized in that by the at least one ink jet print head ( 02 ) at least one intended trajectory ( 03 ) is determined for coating agent drops and that any of the at least one ink jet print head ( 02 ) fixed trajectory ( 03 ) from directly from the ink jet print head ( 02 ) up to one for an impact of the coating agent drops on at least one printing substrate ( 04 ) provided contact area ( 13 ) completely outside a whole through the at least one nozzle ( 11 ) and / or the at least one guiding element ( 09 ) fixed flow path of the fluid is located. Printing device according to claim 3 and / or 4, characterized in that the at least one nozzle ( 11 ) and the at least one guiding element ( 09 ) are formed as components of at least one jet pump. Printing device according to claim 3 and / or 4 and / or 5, characterized in that the at least one ink jet print head ( 02 ) with respect to its ejection direction to one for an impact of coating agent drops on at least one printing substrate ( 04 ) provided contact area ( 13 ) and that within the at least one guide element ( 09 ) the at least one nozzle ( 11 ) is arranged, the nozzle opening ( 12 ) defines a mean outflow direction, which with at least one component parallel to a the guide element ( 09 ) of the at least one inlet opening ( 07 ) to the at least one outlet opening ( 08 ) passing through the flow path of the guide element ( 09 ) and that the at least one inlet opening ( 07 ) at least to the contact area ( 13 ) and / or the contact area ( 13 ) within the at least one guiding element ( 09 ) is arranged. Printing device according to claim 1 and / or 2 and / or 3 and / or 4 and / or 5 and / or 6, characterized in that by the at least one ink jet print head ( 02 ) at least one intended trajectory ( 03 ) is set for coating agent drops and that the at least one ink jet print head ( 02 ) with respect to its ejection direction to one for an impact of coating agent drops on at least one printing substrate ( 04 ) provided contact area ( 13 ) is aligned and that the at least one inlet opening ( 07 ) at least to the contact area ( 13 ) and / or the contact area ( 13 ) within the at least one guiding element ( 09 ) is arranged. Printing device according to claim 3 and / or 4 and / or 5 and / or 6 and / or 7, characterized in that a at least one inlet opening ( 07 ) of the at least one guiding element ( 09 ) bounding border extends in three mutually orthogonal directions and / or has at least one subsection that the for the substrate ( 04 ) provided transport path and / or the substrate ( 04 ) from three sides. Printing device according to claim 3 and / or 4 and / or 5 and / or 6 and / or 7 and / or 8, characterized in that at least one inlet opening ( 07 ) of the at least one guiding element ( 09 ) on the at least one print head ( 02 ) and / or on at least one housing opening of the at least one print head provided for the outlet of coating agent drops ( 02 ) and / or on at least one printhead nozzle of the at least one printhead ( 02 ) and / or that each rectilinear extension of any one of the at least one inkjet printhead ( 02 ) provided trajectory ( 03 ) for coating agent drops over the contact area ( 13 ) through the at least one inlet opening ( 07 ) or suction opening ( 07 ) of the at least one guiding element ( 09 ) runs. Method for applying a coating agent to at least one printing substrate ( 04 ) by means of at least one inkjet printhead ( 02 ) a printing device ( 01 ), wherein coating agent drops on the at least one printing substrate ( 04 ) and wherein in a contact area ( 13 ) of the printing device ( 01 ) when the coating agent drops hit the at least one printing substrate ( 04 ) a coating agent mist is produced and wherein at least one nozzle opening ( 12 ) at least one nozzle ( 11 ) Only at least one fluid is ejected and wherein the coating agent mist by means of at least one suction device ( 06 ) is sucked off. A method according to claim 10, characterized in that the at least one ejected fluid causes a gas flow, in addition to the fluid at least parts of a at least temporarily in the contact area ( 13 ) gas and gas mixture and wherein the gas stream tears the coating agent mist with it. A method according to claim 10 and / or 11, characterized in that a transport path of the coating agent mist exclusively outside the at least one nozzle ( 11 ) runs. Method according to claim 10 and / or 11 and / or 12, characterized in that an entire flow path of the fluid on the one hand and any trajectory ( 03 ) from directly from the ink jet print head ( 02 ) up to one for an impact of the coating agent drops on at least one printing substrate ( 04 ) provided contact area ( 13 ) run separately on the other hand. A method according to claim 10 and / or 11 and / or 12 and / or 13, characterized in that the coating agent mist by means of at least one designed as a jet pump suction device ( 06 ) is sucked off. A method according to claim 10 and / or 11 and / or 12 and / or 13 and / or 14, characterized in that the coating agent mist by means of at least one guide element ( 09 ) of the at least one suction device ( 06 ) is sucked off and that a gas stream within the at least one guide element ( 09 ) by a directed exit of the at least one fluid from at least one nozzle opening ( 12 ) of the at least one nozzle ( 11 ) is generated and that the at least one nozzle opening ( 12 ) of the at least one nozzle ( 11 ) along an internal flow path of the at least one guide element ( 09 ) between an inlet opening ( 07 ) and an exit opening ( 08 ) of the at least one guiding element ( 09 ) is arranged.

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