EP2011655B1 - Method and device for producing and deflecting ink drops - Google Patents

Abstract

The method involves emitting a continuous and cohesive stream from a nozzle (6) of an ink chamber, where sonic pulses act transversely on ink stream (9) at spacing from one another along dispersion direction of the ink stream, which is partially cohesive or in form of drops. Ink drops are separated from the ink stream by the effect of each of the spaced sonic pulses on the ink stream from original dispersion direction of the ink stream such that a group of ink drop streams is produced in parallel to ink drop streams. An independent claim is also included for an apparatus for producing and deflecting ink drops from ink stream.

Description

The invention relates to a method for producing and deflecting ink droplets of a continuous ink jet printer in which a continuous coherent ink jet emerges from a nozzle of a pressure chamber. The invention further relates to an apparatus for generating and deflecting drops of ink from an at least partially contiguous or teardrop-shaped ink jet comprising a pressure chamber with a nozzle for generating a continuously emerging contiguous ink jet.

Continuous inkjet printers have been used industrially for many years to label a variety of products. The previous operating principle of this inkjet printer works so that an ink to be printed from a reservoir via pumps with positive pressure is conveyed into a located in the actual print head pressure chamber, which has a nozzle on the side facing the material to be printed.

The nozzle in this case has an opening diameter in the range of e.g. 30μ to 200μm. From the nozzle now the ink jet initially emerges as a continuous ink jet, which is impractical for a label, since the characters generated here are constructed in this type of labeling of individual dots or individual ink droplets.

In order to disassemble the ink jet into individual similar drops of ink, a modulation element is attached to the pressure chamber, which pressure fluctuations generated in the exiting ink jet, so that after leaving the nozzle after a short time at a defined distance breaks up into individual similar drops of ink. The size of the ink drops depends on the applied modulation frequency, the nozzle diameter and the pressure generated by the pump, and can be set within the limits set by the combination of said parameters for the system. A variation of the droplet size of successive ink droplets is not possible.

Shortly before the tearing off of the ink drops from the leaked ink jet, the ink droplets are each provided with an individual electrical charge, the height of the charge depending on the desired impact position on the product to be labeled. To ensure electrical charging, the ink has a low electrical conductivity.

During the charging process, the ink droplet has not yet broken off from the ink jet emanating from the nozzle of the ink jet printer, so that due to electrical influence free charge carriers in the ink are moved towards or away from the charging electrode, depending on the polarity and magnitude of an external charging voltage Ink chamber and thus the ink reservoir, for example, electrically held at ground potential. The charging electrode has no mechanical contact with the ink jet.

If the ink droplet now tears off the ink jet while it is in the field region of the charging electrode, then the electrical charges migrated through the influence in the droplets remain in the drop volume and this appears to be electrically charged even after the demolition. For example, if the charging electrode is positively charged, as the ink jet enters the electric field of the charging electrode, the negative free carriers in the ink migrate into the field, whereas the positively charged ones free charge carriers in the ink are forced out of the electric field.

As a result, a charge separation takes place immediately prior to the demolition of the droplet at the leading edge of the ink jet, and the charge imbalance thus created in the tearing droplet is retained and the droplet leaves the field region of the charging electrode negatively charged in this example.

Since the ink droplet tears off due to the design and principle during the influence of the charging voltage on the droplet, as described on the detached ink droplet, a charge back whose size at a constant electrical conductivity of the ink according to the height of the applied charging voltage and thus with a change in the charging voltage Also, the amount of charge on each drop can be changed.

On their initially straightforward flight, the electrically charged ink droplets subsequently enter the electrostatic field of a plate capacitor and, depending on their individual charge, are more or less deflected from their rectilinear trajectory and, upon leaving the electrostatic field, fly at a certain angle dependent on their charge continue to their original trajectory.

With this principle, different impact positions can be selected on a surface to be labeled with individual ink droplets, which in this embodiment takes place only in a deflection direction. To hide individual drops from the typeface or when not to print, the ink drops receive a certain fixed charge or remain uncharged, so that they meet after exiting the electrostatic field of the plate capacitor in a collection tube, from where they via a pump system in the ink tank be pumped back. This circulates the unprinted ink in a circle, which has led to the designation of continuous ink jet printers.

A disadvantage of the described conventional design is that due to the systemic deflection of the ink droplets, the ink itself must have a low electrical conductivity, albeit low, so that the individual charge amount required for the electrostatic deflection can be applied to each individual ink droplet.

This limits the number of usable inks because it is not possible or convenient for any desired ink composition to provide these by themselves or via additives with an electrical conductivity. By way of example, this may be an ink which has magnetic properties. Such an ink could, for example, be made electrically conductive by means of an additive, but the trajectories of the respective ink droplets can not be controlled due to the induction phenomena that occur and the associated different additional deflection forces.

The DE 103 07 055 in contrast, describes a method for deflecting ink drops, which deflects the ink drops generated in the usual way by pressure modulation in the ink by means of an ultrasonic wave depending on the applied sound energy to different degrees.

An advantage of this type of deflection is that the inks to be printed no longer need to have electrical conductivity, which allows the use of a large number of different inks with very different properties.

Disadvantageous in the DE 103 07 055 described type is that on the one hand must be a precise synchronization between the drop generation and the droplet deflection, which also the finite The propagation speed of the sound waves at the location of the deflection must be taken into account as a function of the locally prevailing environmental conditions in order to allow a precise deflection of an ink drop to the desired position. A further disadvantage is that when using a simple sound generator due to the size of the sound-generating surface, the acting sound energy acts not only exclusively on the ink drops to be deflected, but at least partially on vorausfliegende and subsequent drops, whereby a precise deflection of the ink drops is only partially possible.

A further disadvantage is that the deflected ink drops all have the same size due to their production, whereby a typeface with different weights only by an overlay of several ink droplets can be generated and thus only in stages can be generated.

Another disadvantage is that the deflected ink droplets are deflected fan-shaped, so that forms a different font size depending on the distance of the printing material to the print head.

The document US 4,190,844 Furthermore, a device is sorted out of the droplet jet by means of droplets which are separated from an already existing jet of separated ink droplets and pass into a collecting device.

The object of the invention is therefore to provide a method and a device with which it is possible to eliminate the disadvantages mentioned and to selectively generate by means of sound energy ink droplets of a certain size and to divert targeted in a particular direction. The object of the invention is furthermore to provide a method and a device with which it is possible to produce different sized ink droplets within a label to be applied and to divert them into a desired direction of flight.

The object is achieved according to the invention in that, in contrast to the known technique, the generation of individual ink droplets from a continuous and contiguous ink jet after leaving the ink jet from the nozzle of the pressure chamber is effected by the fact that laterally on an at least partially contiguous or droplet-shaped ink jet in the direction of propagation of the ink jet acted upon acoustic pulses, wherein the action of each of the spaced sound pulses on the ink jet, an ink droplet from the ink jet dissolved and in particular deflected by the same angular amount from the original propagation direction of the ink jet, so that a family of parallel ink droplets in particular is produced.

The object is further achieved by a device of the type mentioned, in which along the propagation direction next to an at least partially contiguous or droplet-shaped ink jet multiple spaced sound generators are arranged with which spaced each directed to the ink jet sound pulses can be generated, wherein by the action of each spaced apart sound pulses on the ink jet, an ink droplet is detachable from the ink jet and in particular by the same angular amount from the original direction of propagation of the ink jet is deflectable, so that a family of parallel ink droplets in particular can be generated.

The solution is based on the core idea according to the invention that by means of at least one sound pulse, preferably a bundled ultrasonic pulse or hypersonic pulse, a certain portion of the at least partially contiguous ink jet or a drop of an already existing drop-shaped ink jet is released from this and this deviates from the original trajectory Trajectory is distracted. This can be achieved by arranging for each of the particles to be generated transversely to the ink jet, preferably at a 90 ° angle spaced sound pulses per a sound generator or a sound generator for generating a plurality of spaced sound pulses is arranged, which are controlled by a suitable electrical control via a higher-level control and in particular can send out short sound pulses. It may further be inventively provided to focus the sound pulses, for example, characterized in that between a respective sound generator and the ink jet, a focusing device for the sound waves is arranged, with softer emitted from the spaced sound generators equally spaced sound pulses into a plurality of selectively addressable focal points along the propagation direction of the inkjet can be focused.

It may preferably be provided according to the invention that the ink jet passes through the respective focal points or that the focal points can be focused on the ink jet, so that the sound energy of the sound pulses can act in the best possible way on the ink jet.

If, for example, the still at least partially coherent ink jet is hit by at least one sound pulse at a focal point of the sound generator, a certain portion of the ink jet is released by means of the energy transmitted to the ink jet via the sound pulse and the associated transmitted sound pulse, whereby the ink jet is interrupted. As a motion pulse is transmitted transversely to its original trajectory on the detached portion of the ink jet on the sound pulse at the same time, the detached portion leaves the original trajectory of the ink jet and flies at a certain angle to the original Fugbahn on.

Along its further path, this ink jet-released portion forms into an ink drop due to the cohesive forces of the ink. Depending on the nature of the at least one sound pulse and their temporal sequence, it is possible according to the invention, for example with the Extracting a portion of the ink jet at the same time to transmit a certain required momentum for a certain change in direction transverse to the original trajectory, whereby the resulting ink droplet drops takes a new trajectory inclined to the original trajectory.

Are along the original trajectory now according to the invention several e.g. arranged by means of a sound generator arrangement of several sound generators along the original trajectory at several positions ink droplets from the contiguous ink jet or contiguous sections of the ink jet or drops of ink from an already generated ink droplet jet.

So it is possible, e.g. produce similar ink droplets and divert with a preferred respectively identical deflection angle in a new trajectory. As a result, trajectories of the generated and / or deflected drops of ink parallel to each other result in each case at identical deflection angles, which result in a pressure line when hitting a surface to be marked.

The distance of the pressure points thus generated and thus the distance of the parallel trajectories is determined by the distances of the arranged along the original trajectory drop generating positions and the transmitted to the ink droplets pulse transverse to the original trajectory.

The advantage here is that the distance of the ink droplets or the trajectories of the ink drops always remains constant and not continuously increased as in conventional deflection. This ensures in an advantageous manner that a label always independent of the distance of the substrate to the inkjet printhead always with the same font size takes place, whereby it is possible in a simple manner also to label structured surfaces with high quality.

If no same deflection angles are realized, then a crowd of ink droplets may result, which do not necessarily run parallel to one another.

According to the invention, it may be provided in a first embodiment that the sound energy, the sound pulse and the pulse shape at all intended generating positions is substantially equal, whereby a generation of similar ink droplets is made possible with a respective same deflection pulse.

By varying, for example, the time profile of the sound pulses and / or the intensity of the sound pulses and / or the frequency spectrum of the sound pulses and / or focusing, it is thus possible according to the invention to separate ink droplets of different sizes from an at least partially continuous and contiguous ink jet and / or to transmit different deflecting pulses to these detached ink drops, resulting in different deflection angle.

If, in a first embodiment according to the invention, changes for generation and deflection at all generating positions in which the spaced acoustic pulses impinge transversely on the ink jet are carried out in a similar manner, then a family of parallel deflection directions results, whereby for example different font sizes can be generated.

Those areas of the ink jet, which are not needed for a printing line to be built up and which accordingly do not experience any deflection, can pass into the collecting opening of a catching pipe in the usual way and are transported back into the ink circulation, for example by means of a pump.

It can be provided according to the invention in a second embodiment that the respective sound energy, the sound pulse and the pulse shape can be adapted to the intended production positions so that it is possible to dissolve ink droplets of different sizes from the at least partially contiguous ink jet, wherein the respective transmitted deflection pulses is adapted to the respective drop size that result in the same deflection angle and thus parallel to each other extending deflection directions.

It may be provided in a third embodiment according to the invention, in addition to a sound generator arrangement for generating adjacent sound pulses and for deflecting individual ink droplets to provide an upstream second sound generator, which essentially serves to produce individual ink drops from a continuous and contiguous ink jet. The adjacent sound pulses then do not hit an at least partially contiguous ink jet and generate drops that distract them at the same time, but an ink jet is first generated upstream of the contiguous ink jet with the same sound principle, consisting only of ink droplets, then the adjacent sound pulses can act.

In this case, for example, by means of a series of sound pulses of the same energy, intensity, duration and frequency composition from the continuous and contiguous ink jet individual ink droplets of substantially the same size dissolved out, which are deflected in a certain angle to the original direction of flight in a second direction of flight of the second sound generator ,

The ink drops thus produced are then passing through the foci of the first sounder assembly for generating the plurality of adjacent sound pulses along their direction of flight at different positions, respectively deflected that the respective deflection directions generates a family of ink droplets, which preferably run parallel.

It may be expedient here, by means of the second upstream sound generator in a further embodiment, to produce only those ink droplets from the continuous and contiguous ink jet which are actually required in a print image to be written, or in a further embodiment by means of the second sound generator a continuous sequence in particular to produce equidistant drops of ink and in each case deflect only the ink droplets required for a printed image by means of the first sound generator arrangement, so that in each case only a single catching device for the unneeded portions of the ink can be present.

As a sound generator for generating individual drops of ink and / or their diversion, for example, all known methods for generating sound can be used such as electrodynamic transducers, piezoelectric transducers, electrostrictive transducers, magnetostrictive transducers, electrostatic transducers, plasma generators, etc. according to the invention at least a portion of their generated sound waves in be focused on a focus or in a variety of focal points.

For this purpose, for example, an acoustic lens, a reflector material or a combination thereof can be used. According to the invention, it is also possible to design the sound generator and in particular a sound-generating surface in such a way that it acts, for example, as a Fourier-transformed at least one substantially punctiform sound event and thus bundles in its reverse operation sound waves which emanate from this surface substantially in at least one focal point. For this purpose, the sound-generating surface in a simple case, for example, as a Fresnel zone plate be executed, wherein the sound-generating surface is divided into individual individually electrically controllable concentric areas.

By appropriate electrical control of the respective areas in terms of amplitude, phase, time course and frequency spectrum, it is possible without additional acoustic lenses or reflectors to generate a corresponding sound pulse and to focus this in at least one focal point. It is also possible, with a corresponding configuration of the sound-shaped surface and a corresponding electrical control of the respective regions, to generate a plurality of foci which are arranged one behind the other and can be controlled independently of one another, whereby different successive deflection positions can be achieved.

Figur 1:

eine Anordnung zur Erzeugung von Tintentropfen und deren Ablenkung gemäß des Standes der Technik

Figur 2:

eine erste erfindungsgemäße Ausführung zur Erzeugung von gleichartigen Tintentropfen und deren gleichartige Ablenkung mit einer ersten Schallerzeugeranordnung

Figur 3:

eine zweite erfindungsgemäße Ausführung zur Erzeugung von unterschiedlichen Tintentropfen und deren gleichartige Ablenkung mit einer ersten Schallerzeugeranordnung

Figur 4:

eine dritte erfindungsgemäße Ausführung zur Erzeugung von Tintentropfen und deren Ablenkung mit einer ersten fouriertransformierten Schallerzeugeranordnung

Figur 5:

eine vierte erfindungsgemäße Ausführung mit zwei voneinander unabhängigen Schallerzeugeranordnungen mit kontinuierlicher Tropfenerzeugung

Figur 6:

eine fünfte erfindungsgemäße Ausführung mit zwei voneinander unabhängigen Schallerzeugeranordnungen mit wahlweiser Tropfenerzeugung

Figur 7:

eine sechste erfindungsgemäße Ausführung mit drei voneinander unabhängigen Schallerzeugeranordnungen

Embodiments of the invention and the prior art show the following figures. Show it:

FIG. 1:

an arrangement for the production of ink drops and their deflection according to the prior art

FIG. 2:

a first embodiment according to the invention for the production of similar drops of ink and their similar deflection with a first sound generator arrangement

FIG. 3:

a second embodiment of the invention for generating different ink droplets and their similar deflection with a first sound generator assembly

FIG. 4:

A third embodiment according to the invention for generating ink droplets and their deflection with a first Fourier-transformed sound generator arrangement

FIG. 5:

a fourth embodiment of the invention with two independent sound generator arrangements with continuous droplet generation

FIG. 6:

a fifth embodiment of the invention with two independent sound generator arrangements with optional droplet generation

FIG. 7:

a sixth embodiment of the invention with three independent sound generator arrangements

FIG. 1 shows for comparison with the invention by way of example a printhead of the known type of continuous ink jet printer. The ink 1 is first pumped from a reservoir 2 by means of a pump 3 via leads 4a into the pressure chamber 5, at one end of which a nozzle 6 is introduced. By means of additionally mounted on the pressure chamber modulation means 7, the pressure in the pressure chamber 5 is modulated so that the emerging from the nozzle 6 ink jet breaks 9 at a short distance after its exit into individual ink droplets 11 of substantially the same size. Shortly before breaking up, the individual ink droplets 11 are provided with an individual electrical charge via a charging electrode 8.

Along their trajectory 100, the ink drops 11 now enter an electric field 21, which is formed by means of the electrodes 20a and 20b of the plate capacitor 20. Depending on the charge quantity and the polarity of the charges on the ink droplets 11 and the polarity and strength of the electric field 21 in the field space of the plate capacitor 20, the individual ink droplets are deflected into different spatial directions 101, 102 shown by way of example.

The total number of possible deflection angles depends only on the control of the charging electrode and is not limited in principle. The individual plates 20a and 20b of the plate capacitor 20 can thereby be inclined towards each other, as in FIG. 1 shown. However, it is also possible to use plates arranged parallel to one another without restriction of generality.

The polarity and strength of the electric field 21 is expediently kept substantially constant in this embodiment, since a change in the field strength to a plurality of drops, which are located in the field space of the plate capacitor at this time, simultaneously affects and thus an influence of a single drop is impossible.

After leaving the field space 21 of the plate capacitor 20 no more electrostatic force acts on the ink drops 11 and they maintain their new trajectories 101, 102 at. This results in a fan-shaped array of trajectories. For example, ink drops 11, which have not been charged or only slightly charged because they must be discarded from the typeface, experience no or only a slight deflection in the electrostatic field 21 of the plate capacitor 20 and strike into an opening 19 of a catch tube 18 for ink return. The ink thus collected is returned to the ink container 2 through leads 4b and returned to the ink circuit.

It is easy to see that this principle works only with inks which have an electrical conductivity, since otherwise an electrostatic charging of the ink drops can not take place.

FIG. 2 shows a first embodiment according to the invention for the generation and deflection of ink drops of a not necessarily electrically conductive ink and in particular an electrically non-conductive ink. The ink 1 is for this purpose pumped from a reservoir 2 by means of a pump 3 via leads 4a in a pressure chamber 5, at one end of which a nozzle 6 is located.

Due to the substantially static pressure generated by the pump 3 in the pressure chamber 5, the ink 1 exits the pressure chamber 5 via the nozzle 6 as a continuous and contiguous ink jet 9 along a propagation direction 100 and after a certain distance enters the area of the sound generating arrangement 400, which comprises, for example, a number of sound generators 40, 41, 42,..., 47 arranged one after the other along the direction 100. Each of the sound generator systems 40, 41, 42,..., 47 comprises, for example, a sound generator 40a, 41a, 42a,..., 47a located in a holder 40d, 41d, 42d, Inkjet 9 facing side has a respective focusing device 40b, 41b, 42b, ..., 47b.

The distance of the sound generator systems 40, 41, 42,..., 47 to the ink jet 9 and in particular the configuration of the focusing devices 40b, 41b, 42b,..., 47b is determined such that the focal points of the focusing devices 40b, 41b, 42b, ..., 47b on which along the propagation direction 100 moving ink jet 9 fall. Thereby, the sound pulses 140, 141, 142, ..., 147 emitted from the sound generators 40a, 41a, 42a, ..., 47a are concentrated in a small area on the ink jet 9 so as to be incident on the ink jet 9 in the respective ones Foci 40c, 41c, 42c, ..., 47c a certain sound energy and a certain sound pulse is transmitted to a specific area of the ink jet 9. By means of the first sound generator 40a, it is possible to extract a certain section of the still continuous and coherent ink jet 9. After a first release of a drop, the following sound generators then act only on the at least partially contiguous ink jet.

Depending on the respectively used pulse duration, pulse shape, frequency composition and the sound energy in the sound generators 40a, 41a, 42a, ..., 47a converted sound energy is in each case more or less sound energy and each a more or less large sound impulse on the transmit respective extracted route section, so that the respective sections of the route can experience certain deflection and thus it is possible by a corresponding control of the sound generator systems 40, 41, 42, ..., 47 by means of a higher-level control, not shown, selectively generate individual sections and thus for example, to address a print line.

After a short time due to the cohesive forces prevailing in the interior of the ink, the sections thus removed form individual ink droplets 13 along their respective further deflection directions 101, 102, which ink droplets 13 can be used in a known manner for labeling or marking.

Because the ink droplets 13 required for printing are produced along the propagation direction 100 at different positions with the same deflection angle, the new directions of flight 101, 102 of the ink droplets 13 form a parallell to each other, whereby the same is independent of the distance of the printing material to the print head Font size results. The size of the font depends essentially on the original speed of the ink jet in the direction 100, the distance of the sound generator systems 40, 41, 42, ..., 47 to each other and each transmitted transversely to the direction of deflection.

Aspects of the ink jet that are not required for a typeface and thus need to be discarded are not distracted by the sonic generator systems 40, 41, 42, ..., 47, so that they fly undistracted along their original propagation direction 100 and into a collection port 19 of a Catch pipe 18 reach and 4b transported in a known manner via return lines in the ink circulation.

FIG. 3 shows a second embodiment of the invention for generating ink droplets and their deflection, in which it is possible by a respective different control of the deflection systems 40, 41, 42, ... to produce 47 different droplet sizes, wherein the respective deflection angle can be kept constant. For this purpose, for example, the respective pulse durations and / or amplitudes and or pulse counts and / or focussing of the respective sound generator systems 40, 41, 42; ..., 47 adapted so that different lengths of track sections can be dissolved out of the ink jet, which form due to the internal cohesive forces after a short time to ink droplets.

FIG. 4 shows a third embodiment according to the invention for the generation of ink drops and their deflection, in this embodiment, the sound generator assembly 500 is designed so that they can be operated in particular areas 50, 51, 52, ... 57 as respective Fourier transform each having a preferably punctiform sound event ,

This makes it possible to operate such a sound generator arrangement 500 without focussing device, since the sound waves 150, 151, 152,... 157, with a corresponding activation of the respective sound-generating elements combined into a certain number of areas 50, 51, 52, Segments 500a may be bundled by superimposing the respective amplitudes and phases into respective common foci 50c, 51c, 52c, ... 57c, whereby, in a similar manner as described, individual path portions may be extracted and deflected from the ink jet 9.

As a result, it is also possible, for example, to carry the respective focal point 50c, 51c, 52c,... 57c at least for a certain distance during the sound pulse with the respective ink droplet to be deflected, whereby a particularly effective transmission of the sound energy to the droplet can take place. By the summary of a certain number of Sound generating segments 500a to a respective area, it is also possible to selectively generate a different number of areas and thus a different number of deflected ink jet directions 101, 102nd

FIG. 5 shows a fourth embodiment of the invention for generating ink droplets and their deflection, in this embodiment, a second upstream sound generator system 60 is provided, which is arranged between the pressure chamber 5 and the first sound generator assembly 400.

By a corresponding control of the sound generator system 60 by means of a higher-level control, not shown, it is possible to disassemble the emerging from the nozzle 6 continuous and contiguous ink jet 9 in a first step, for example, in a series of the same, in particular equidistant ink drops 11, for example, with a certain frequency of sound pulses of substantially the same time course, the same amplitude and phase and the same frequency spectrum and / or focusing on the ink jet 9 can be acted upon.

For this purpose, the sound generator system 60, for example, a recording device 60d for receiving a sound generator element 60a, and a focusing device 60b, with which the sound waves generated by the sounder element 60a 160 are focused into a focal point 60c, which lies at a certain point of the propagation direction 100 of the ink jet , This makes it possible to disassemble the ink jet 9 by means of a suitable sequence of sound pulses into a series of substantially identical drops of ink which are deflected into a first new deflection direction 100a due to a deflection pulse transmitted thereto simultaneously.

The subsequently arranged first sound generator arrangement 400 is in this case arranged along the new deflection direction 100a such that the focal points 40c, 41c, 42c,..., 47c of the respective sound generator systems 40, 41, 42,..., 47 lie in the propagation direction 100a , This makes it possible to deflect individual ink drops previously generated by the sound generator system 60 by means of a synchronized sound pulse from their propagation direction 100a into a new second deflection direction 101, 102.

The synchronization between the generation of the ink droplets by means of the sound generator system 60 and the respective deflection by one of the sound generator systems 40, 41, 42,..., 47 can take place, for example, electronically or by means of sensors, not shown, along the flight path 100a, whereby the position and / or the frequency of the drops can be determined. Unintentional ink droplets meet in the usual way in a collecting opening 19 of a catching pipe 18 and are transported back via return lines 4b in the ink circulation.

FIG. 6 shows a fifth embodiment of the invention for generating ink droplets and their deflection, in this embodiment as in the already described fourth embodiment of the invention, a second sound generator system 60 is provided, which is arranged between the pressure chamber 5 and a first sound generator assembly 500 used in this embodiment, which works as a "Fourier transformed" sound generator system.

Due to the fact that the focal points 50c, 51c, 52c,... 57c of the sound waves can be generated by a corresponding activation of the associated sound-generating segments 50a, 51a, 52a,... 57a, it is also possible, for example, a different number of times Focal points 50c, 51c, 52c, ... to be generated by grouping more or less segments 500a into respective segment groups and by a corresponding control Focus 50c, 51c, 52c, ... form. As a result, it is also possible, for example, to carry the respective focal point at least for a certain distance during the sound pulse with the respective ink droplet to be deflected, whereby a particularly effective transmission of the sound energy to the droplet can take place.

FIG. 7 shows a sixth embodiment according to the invention for the generation of ink droplets, and their deflection, in this embodiment, as already described, a second sound generator system 60 is provided for the production of ink droplets. With the sound generator system 60, however, only those ink droplets are generated from the contiguous ink jet 9, which are used for printing. Unnecessary sections of the ink jet 9 arrive in this embodiment in the collecting opening 19 of a catch tube 18, which is located immediately after the sound generator system 60 in the propagation direction 100 of the ink jet. It goes without saying that instead of the sound generator arrangement shown by way of example for deflecting the ink jets, it is also possible to use a sound generator arrangement 500 which acts as a Fourier transform.

In particular, it is also possible, in particular, to produce ink droplets of different sizes from the continuous ink jet by means of the second sound generator system, wherein their corresponding deflection by means of the first sound generator arrangement can be synchronized with the respective size of the droplets and the desired deflection direction.

Claims (26)

1. Method for producing and deflecting ink drops of a continuously operating inkjet printer, in which a continuous cohesive ink jet emerges from a nozzle of a printing chamber, wherein spaced sound pulses (140, 150) act laterally on an at least partly cohesive or drop-like ink jet (9, 11, 12) in the direction of propagation of the ink jet (100, 100a), wherein an ink drop (11, 13) is detached from the ink jet (9, 11, 12) by the action of each of the spaced sound pulses (140, 150) and is deflected in particular by the same angle from the original direction of propagation (100, 100a) of the ink jet (9, 11, 12), so that a family of in particular parallel ink drop jets (13) is produced.
2. Method according to Claim 1, characterized in that the spaced sound pulses (140, 150) meet the at least partly cohesive ink jet (9, 12) laterally with a respect to the direction of propagation (100) and a section of the ink jet (9, 12), on which one of the spaced sound pulses (140, 150) acts, is detached from the at least partly cohesive ink jet (9, 12) and deflected from its original direction of propagation (100), the detached section forming an ink drop (13) as a result of cohesive forces during the flight.
3. Method according to Claim 1, characterized in that sound pulses (160) acting at a point of the cohesive ink jet (9), laterally on the ink jet (9), in a time sequence and locally before the spaced sound pulses (140, 150) each detach a section of the ink jet (9), on which such a sound pulse (160) acts, from the cohesive ink jet (9) and deflect it from its original direction of propagation (100), the detached section forming an ink drop (11) by cohesive forces during the flight, so that a deflected drop-like ink jet (11) is produced, along the direction of propagation (100a) of which the spaced sound pulses (140, 150) act in each case on the ink drops (11).
4. Method according to any of the preceding claims, characterized in that sound generators (40,...47, 60) which are actuatable in a pulsed manner and in each case are present outside the printing chamber (5) and are arranged along the direction of propagation (100, 100a) of the at least partly continuous and cohesive (9, 12) and/or drop-like (11) ink jet (9, 11, 12) are used for producing the sound pulses (140, 150, 160), in each case sound pulses (140, 150, 160) which are directed laterally, in particular at a right angle to the respective ink jet (9, 11, 12), being produced by a sound generator (40,...47, 60).
5. Method according to any of the preceding claims, characterized in that optionally ink drops (11, 13) are detached from the at least partly cohesive or drop-like ink jet (9, 11, 12) by sound pulses (140, 150, 160) acting on the ink jet (9, 11, 12) transversely to the direction of propagation (100, 100a) of the ink jet.
6. Method according to any of the preceding Claims 3 to 5, characterized in that the cohesive ink jet (9) is treated with successive sound pulses (160) transversely to the direction of propagation (100) of the ink jet (9) in such a way that ink jet sections deflected (11) from the original direction of propagation (100) and undeflected ink jet sections form, undeflected sections entering a collecting device (18, 19) arranged in the original direction of propagation (100) and being transported back into the ink circulation, and the deflected sections (11) forming a drop-like ink jet (11) on which the spaced sound pulses (140, 150) act along the direction of propagation (100a).
7. Method according to any of the preceding Claims 3 to 5, characterized in that the cohesive ink jet (9) is treated with successive sound pulses (160) transversely to the direction of propagation (100) of the ink jet (9) in such a way that only ink jet sections (11) which are deflected from the original direction of propagation (100) form, which ink jet sections (11) form a drop-like ink jet (11) with substantially equidistant ink drops (11), on which the spaced sound pulses (140), 150) act along the direction of propagation (100a).
8. Method according to any of the preceding claims, characterized in that the detached sections form drops (11, 13) having substantially the same size.
9. Method according to any of the preceding claims, characterized in that the detached sections form ink drops (11, 13) having a different size.
10. Method according to any of the preceding claims, characterized in that ink drops (13) of different sizes are deflected in directions (102) parallel to one another from the ink jet (9, 11) by a plurality of spaced sound pulses (140, 150) independent of one another and acting on the ink jet transversely to the direction of propagation (100, 100a) of the at least partly cohesive ink jet (9, 12).
11. Method according to any of the preceding claims, characterized in that the drops (11) not deflected from an ink jet (9, 11, 12) or at least partly cohesive sections (12) enter a collecting device (18, 19) and are transported back into the ink circulation.
12. Method according to any of the preceding claims, characterized in that the sound pulses (140, 150, 160) are focused onto the at least partly cohesive or drop-like ink jet (9, 11, 12).
13. Method according to Claim 12, characterized in that the sound pulses (140, 150, 160) are focused by means of a focusing device (40b,...47b, 60b) onto a section of the at least partly cohesive ink jet (9, 12) or an ink drop (11).
14. Method according to any of the preceding claims, characterized in that the sound pulses (140, 150, 160) are produced by means of at least one electrodynamic, electrostatic, magnetodynamic, magnetostatic or piezoelectric transducer (40a,...47a, 50, 60a).
15. Method according to any of the preceding claims, characterized in that a sound pulse (150) is produced by means of a sound generator (50), whose shape and/or arrangement of sound-producing elements (500a) corresponds to the Fourier transformation of at least one substantially point-like sound pulse at a distance form the ink jet (9, 11, 12), so that at least one sound pulse (150) which is focused without additional focusing elements onto the ink jet (9, 11, 12) forms as a result of an actuation of the sound generator (50).
16. Method according to any of the preceding claims, characterized in that the focus (50c) of the sound pulse (150) follows the movement of the ink jet (9, 11, 12) during the duration of said sound pulse (150).
17. Method according to Claim 15 or 16, characterized in that the number of focal points (50c) is optionally variable by a logical combination of different sound-producing elements/segments (500a) to give different ranges.
18. Method according to any of the preceding claims, characterized in that the extent of the deflection of a section or drop (11) depends on and/or is controlled by the energy and/or the momentum and/or the focusing of a sound pulse (140, 150, 160).
19. Device for producing and deflecting ink drops, comprising a printing chamber having a nozzle for producing a continuously emerging cohesive ink jet, wherein a plurality of spaced sound generators (40,...47, 50, 60) by means of which spaced sound pulses (140, 150) directed in each case at the ink jet (9, 11, 12) can be produced are arranged along the direction of propagation (100, 100a), adjacent to an at least partly cohesive or drop-like ink jet (9, 11, 12), wherein an ink drop (13) can be detached from the ink jet (9, 12) by the action of each of the spaced sound pulses (140, 150) on the ink jet (9, 12) and in particular can be deflected by the same angle from the original direction of propagation (100) of the ink jet (9, 12), so that a family of in particular parallel ink drop jets (13) can be produced.
20. Device according to Claim 19, characterized in that optionally ink drops (11, 13) can be detached from the at least partly cohesive or drop-like ink jet (9, 11, 12).
21. Device according to either of the preceding Claims 19 and 20, characterized in that the device comprises a collecting device (18, 19) and an ink circulation, the undetached regions of the ink jet entering the collecting device (18, 19) and being transported back into the ink circulation.
22. Device according to any of the preceding Claims 19 to 21, characterized in that a sound generator (40,...47, 50, 60) is in the form of an electrodynamic and/or electrostatic and/or magnetodynamic and/or magnetostatic and/or piezoelectric transducer.
23. Device according to any of the preceding Claims 19 to 22, characterized in that it has at least one focusing device (40b,...47b, 60b) for focusing sound pulses (140, 160) onto a section of the at least partly cohesive or drop-like ink jet (9, 11, 12).
24. Device according to any of the preceding Claims 19 to 22, characterized in that a sound generator (50) has a shape and/or arrangement of sound-producing elements (500a) which corresponds to the Fourier transformation of at least one substantially point-like sound pulse at a distance form the ink jet, so that at least one sound pulse (150) which is focused without additional focusing elements onto the ink jet (9, 11, 12) can be produced by an actuation of the sound generator (50).
25. Device according to Claim 24, characterized in that the number of focal points (50c) is optionally variable by a logical combination of different sound-producing elements (500a) to give different ranges.
26. Device according to either of the preceding claims 24 and 25, characterized in that the respective focal points (50c) are capable of following the movement of the ink jet (9, 11, 12) during the respective duration of the respective sound pulses (150).

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