EP2977212B1 - Direct printing machine with an ink supply system - Google Patents

Description

The present invention describes a direct printing machine for printing on containers, such as bottles and a corresponding printing method.

State of the art

From the prior art direct printing machines are known for printing.
For example, from the US 8,418,608 a direct printing machine is known, which has an ink supply, which is arranged in a stationary part of the direct printing machine. This ink supply system includes a main tank in the stationary part of the machine. From this, for example, rotary distributor transfers ink to one or more printing modules. The printing modules are located in the rotating part of the printing press. The pressure modules can also be assigned auxiliary tanks.

The EP 2605909 B1 shows a direct printing machine with a plurality of printing modules, which are each arranged with a container recording on the carousel and allow printing of a container at different heights. The print modules each require separate ink feeds.

The US 2012/0255450 A1 The closest prior art in particular shows a direct printing machine according to the preamble of claim 1.

However, the previous direct printing machines are very complicated in terms of ink supply, which can often lead to machine failures or leaks.

task

Starting from the prior art, the object to be solved of the invention is to provide a direct printing machine comprising an improved ink supply system.

solution

This object is achieved by the direct printing machine according to claim 1 and the method for printing containers according to claim 11. Advantageous developments of the invention are covered in the subclaims.

According to the invention, an ink supply system comprising at least one ink tank and at least one supply line capable of supplying ink from the ink tank to at least one of the printing stations is arranged with the carousel rotating on the direct printing machine. By the arrangement of the ink supply system running on the carousel, the ink supply to the individual printing stations is facilitated. On structurally complicated Drehverteilungssysteme can be dispensed with. The machine is tintendrehverteilerlos formed.

The ink tank and the entire ink supply system are arranged on the rotating part of the direct printing machine. This means that the tank and / or the entire ink supply system rotates with the carousel / rotating part of the machine, if this is in operation. This means that no stationary, ie in the stationary part of the machine is provided relative to this stationary arranged tank and that the ink supply system is formed without rotary distributor.

According to the invention, a stationary tank is provided which can only be connected to it at standstill of the direct printing press, wherein the stationary tank can be connected to the ink tank via a refill port connected to the ink tank, which is arranged at the circumference of the carousel.

In one embodiment, each printing station comprises a printing segment, which contains at least one printing module and is detachably connected to the station, wherein in the installed state there is a connection of the printing module to a supply line. An exchange of pressure segments can be easily ensured.

Each printing station on the carousel or each printing segment comprises as an embodiment of the printing module in particular at least one digitally controlled inkjet printhead.

In a development of this embodiment, it is provided that each printing station comprises a container receptacle, wherein the container receptacle and the printing segment are formed as separate components or as a component. The replacement of the pressure segments can be facilitated because the container recordings do not need to be replaced at the same time.

It can be provided that the printing segment comprises a plurality of printing modules, which are arranged concentrically around the longitudinal axis of a container located in the printing station. The concentric arrangement allows a simple ink supply via corresponding supply lines, for example from above.

The direct printing machine according to the invention can be characterized in that each printing module is associated with a shield, which can be moved between a rest position and a shielding position in which the shield shields pressure nozzles of the printing module. The shielding of the individual printing modules protects the printing nozzles from contamination by ink from other printing modules in the environment and can be used, for example, in the application of UV light to cure ink on the container to prevent the ink from drying on the printing nozzles.

In another embodiment, the direct printing machine is characterized in that the ink supply system further comprises at least one controllable flow pump for pumping ink from the ink tank to the printing stations and at least one return pump for pumping ink from the printing stations into the ink tank. In this embodiment it can be ensured that there is always a negative pressure applied to the printing nozzles of each printing station, so that a dripping of printing ink can not happen unintentionally, provided that the print head is inactive.

Furthermore, the supply line can comprise at least one main line for transporting ink from the ink tank, which extends along at least part of the circumference of the carousel, one or more secondary lines lead from the main line to the printing stations and at least one discharge line from the printing stations to the main line lead, wherein ink via a first connection of the main line to the ink tank discharged from the ink tank and can be introduced via a second connection of the main line in the ink tank. With this embodiment, the number of pumps required can be reduced since it suffices if a corresponding pressure is produced in the intended main line. Furthermore, ink can be saved as unused ink can be pumped back into the ink tank.

In a further embodiment it is provided that a plurality of ink tanks are provided, wherein each ink tank are assigned separate supply lines, wherein the ink tanks are arranged either concentrically about an axis of rotation of the carousel or one above the other parallel to the axis of rotation of the carousel or not concentric distributed. By a plurality of ink tanks, on the one hand, more complex print images can be produced (for example multicolored) and, on the other hand, it is possible to prevent downtimes of the machine due to an empty ink tank. In the case of several ink tanks, each tank is preferably assigned to a specific ink color. The inks available in the tanks may have different colors in pairs, but several tanks or a subset of the tanks may contain the same color.

The ink supply system may be arranged in the carousel. The arrangement of the ink supply system directly in the carousel has the advantage that the supply paths can be chosen as short as possible.

Furthermore, it is advantageous if the refill connection is arranged between two adjacent printing stations. Refilling the ink tanks or the ink tank can be done by stopping the direct printing machine in a manner suitable for the operator Position to reach the refill port are guaranteed. In particular, the refill port can be arranged at a height between 0.1 and 2.5 m and preferably between 0.5 and 2 m above the ground on which the machine is installed.

In particular, when using multiple tanks, multiple refill ports may also be present, each of which is associated with a tank. The individual refill connections can be arranged at the same position in the circumferential direction of the machine, for example at different heights, or alternatively between respectively different stations at the same height. The arrangement at the same position in the circumferential direction means that the refill connections are all arranged between exactly two adjacent printing stations. The refill connections can be arranged, for example, as "bundles" between the printing stations or, for example, be arranged on a straight line parallel to the rotational axis of the carousel at a distance from one another.

In particular, each printing segment or each printing station comprises a rotary drive, which is coupled to the receptacle of the container. With the drive, the containers are rotated during printing relative to the carousel, in particular about its longitudinal axis, to produce a relative movement of the print head to the container.

Particularly preferably, the machine runs continuously during operation. In certain cases, however, it can also be operated intermittently.

In an advantageous embodiment, only one color is provided in a machine and a plurality of similar machines in the transport direction of the container are successively set up to successively apply different colors to the container.

The stationary tank is provided with a connection which according to the invention can be connected to it only when the machine is at a standstill. This can be designed so that it has a coupling which can be automatically docked via drives to the refill or the connections. Still in the stationary part can be provided for this purpose, a pump which is activated for refilling.

The machine rotates in one embodiment about a vertically oriented axis of rotation which intersects the center of the earth.

It can also be provided (per color) an additional auxiliary tank on the rotating part of the machine, which is constantly fed by a co-rotating main tank, in which the invention is refilled. The auxiliary tank can be at a certain height and its level can always be kept constant by a control using a sensor. From the auxiliary tank, the ink passes in particular to the previously mentioned flow pump.

The method according to the invention for printing on containers such as bottles is characterized in that the containers are received and printed by printing stations on a rotating carousel, wherein an ink supply system rotating with the carousel supplies ink from an ink tank to at least one of the printing stations via a feed line Direct printing machine tintendrehverteilerlos is formed.

According to the invention, a stationary tank is provided with a connection which is connected to it only when the direct printing press is at a standstill, the stationary tank being connected to the ink tank via a refill connection connected to the ink tank, which is arranged on the circumference of the carousel, for refilling the ink tank ,

This method allows a much more direct supply of ink to the printing stations, whereby long transport paths of the printing ink can be minimized.

In one embodiment, the method is characterized in that ink is pumped from the ink tank into the supply line via a controllable feed pump and pumped back into the ink tank via a return pump ink, wherein the pumping capacity of the return pump is higher than the pumping line of the flow pump at any time so that a negative pressure is applied to printing nozzles of the printing station.

In a further development of this embodiment, the pumping capacity of the feed pump is controlled as a function of the fill level of the ink tank and / or as a function of the rotational speed of the carousel. A desired level of pressure in the lines for printing can thus be set at any time as a function of the operating parameters.

The refill port may be located between two adjacent printing stations.

In particular, when refilling of the ink tank is necessary, the carousel can be stopped to a standstill in which the refill port is accessible from outside the direct printing machine. Downtime for refilling ink can be minimized and the total throughput or overall performance of the machine can be increased. In particular, the machine comprises at least one conveyor which inserts the containers into the machine and one which ejects the printed containers from the machine. When the machine is at a standstill, the rotational position is selected so that the refill port stops at a different position in the circumferential direction than the two conveyors.

In an advantageous embodiment, ink is removed from the ink tank along a main conduit transported and supplied via secondary lines to individual printing stations and passed via discharges from the printing stations to the main line, the ink via a first port The main line from the ink tank is piped into the main line and routed via a second connection of the main line from the main line into the ink tank. For this embodiment, only one flow and one return pump are required, which produce a desired pressure level in the main line, wherein the supply of ink to the individual pressure stations via the secondary lines, which allows a targeted pressure supply.

In particular, a level sensor is arranged in each tank of the machine, with which the level of the tank is measured. In particular, with the use of this sensor, the operator can be displayed (for example, on a touch screen of the machine), how much ink is still in the tank, or how long the machine can still be operated with the current filling at its current performance. With a certain remaining production time, a warning signal can be issued that the operator can prepare for refilling the tank. In order not to eject unprinted containers, the machine may automatically stop when the tank becomes empty.

The containers to be printed are in particular PET bottles.

Also provided is a method of cleaning the ink supply (tanks, lines and possibly the printheads). For this purpose, residues of ink from the tank or tanks are first removed via a drain connection (and possibly reused after cleaning) and then filled into the refill connection or into the refill connections a cleaning agent, which of the already existing pumps (flow pump and return pump For example) is passed through the ink supply system over a period of time. After cleaning, the particular liquid cleaning agent is removed via a or the drain port and refilled ink. In particular, cleaning may be performed at regular intervals or, for example, when an operator refills a wrong ink color in a tank. To avoid the latter, a system may be present at the refill ports which avoids incorrect refilling. For example, it is possible to provide adapters on the refill connection and respectively refill cartridges adapted to the color per color, which are adapted to one another via an individual geometry of the connection opening or the spout openings of the cartridges. The method of cleaning and / or the system at the refill ports may additionally be provided on the machine, but it may also be an independent invention as described above.

Brief description of the figures

Fig. 1

Schematic representation of a container treatment machine according to an embodiment.

Fig. 2a + b

Schematic representation of several embodiments of the leads.

Fig. 3

Schematic representation of an embodiment of the pressure segment.

Fig. 4

Further schematic representation of an embodiment of the pressure segment.

Fig. 5

Schematic representation of an embodiment of the container treatment machine with refill.

Fig. 6a + b

Schematic representation of possible shielding devices of pressure segments and / or containers.

Detailed description

Fig. 1 shows a direct printing machine 100 according to an embodiment of the invention. In this embodiment, the direct printing machine is designed as a rotary machine with a carousel 101. The carousel 101 is disposed on a fixed portion 120 of the container handling machine and includes one or more printing stations 110 around the circumference of the entire carousel that can print on a container. For this purpose, the printing stations comprise at least one printing segment 111, in which one or more printing modules can be arranged. In principle, the spatial arrangement of the printing modules in the printing segment is arbitrary. The printing modules can be arranged at a constant distance around an introduced into the printing station bottle or container 130 introduced, for example, on a semicircle. Alternatively, a plurality of printing modules may be arranged one above the other in planes extending parallel to the axis of rotation. Also combinations of it are possible.

In order to ensure a supply of ink to the printing modules, an ink supply system 103 is provided. This ink supply system is arranged with the carousel 101 co-rotating, which need not necessarily be located directly in the carousel. The ink supply system comprises at least one ink tank 102 in which the ink necessary for printing the containers is held, and one or more supply lines 131 to 13n, each of which is connected to a respective print segment or print module of a print segment. It can also be provided that more than one ink tank is provided. In particular, when multi-color printing is intended, it is advantageous to separate each other Provide ink tanks, for example, one above the other, can be arranged concentrically parallel to the axis of rotation or with the carousel co-rotating non-concentric distributed. In the latter case, the ink tanks are preferably mounted directly on the carousel, so that no additional space in the standing part 120 of the printing machine 100 must be kept free to allow rotation of the ink tanks. In particular, the tanks may be designed as ring lines.

Alternatively, it can also be provided that a plurality of rotary machines or carousels are provided, each of which can realize a monochrome printing. The containers can then be transferred from one carousel to the next and in each carousel a corresponding monochrome print image can be applied. For this purpose, a central carousel be provided, which allows both the feeding of the container and the removal of the containers to and from the respective carousels. The individual carousels carrying out the printing then have an ink tank and a corresponding ink supply system and can be used according to the method described in US Pat Fig. 1 be shown carousel. Alternatively, several carousels, which in each case completely outfit the containers with all the colors, can be supplied by a central distributor.

Fig. 2a + b show plan views of a direct printing machine 100 according to the invention, wherein the lines to the individual pressure segments or pressure modules 211-218 are also shown. In the in Fig. 2a illustrated embodiment, a central tank 102 is provided, which is arranged concentrically around the rotation axis R. It is understood that the statements according to Fig. 2a and 2b also to a plurality of tanks, which are either one above the other, parallel to the axis of rotation concentrically arranged or distributed non-concentrically on the carousel, can be transmitted. The shape of the ink tank is in principle arbitrary. Thus, as shown, cylindrical, concentric with the axis of rotation R of the carousel arranged tanks are provided. But even angular or irregular shaped tanks are possible. The shape of the ink tanks can also be adapted to the rest of the structure of the carousel to leave enough space for other assemblies, such as control or cooling. It can also be provided that more than one ink tank per color is provided. For example, auxiliary tanks may be provided co-rotating in the rotating part of the direct printing machine with the carousel. These can provide a temporary supply of ink if the main tanks are empty or nearly empty to reduce downtime.

According to the in Fig. 2a In the embodiment shown, a main line 205 is provided, through which ink can be conveyed out of the ink tank 102. This is at least one flow pump 281 and a return pump 282 are provided. The advance pump 281 pumps ink from the tank 102 and carries it with a certain pressure through the main line 205. The return pump 282, however, sucks the ink from the main line and leads them back in the illustrated arrow direction in the ink tank 102. On the main line 205th one or more sub-lines 251-258 are arranged leading from the main line to the pressure segments 211-218. Through these secondary lines, for example, by opening a corresponding valve or two valves of the secondary line, ink is diverted from the main line and passed into the pressure segment. As shown by the direction of the arrow, ink can be diverted from the main line and routed to the print modules 211-218 by the sub-lines 251-258, but also ink can be conveyed from the print modules back to the main line. It is understood that for this purpose each secondary line comprises two separate lines, not shown, from which an ink from the main line leads to the printing module and the other ink from the printing module leads back into the main line. The secondary lines may have different diameters, so that friction losses (= pressure reduction) can be compensated. Thus, the first line 257 passed through in the series may have a larger diameter than the last line 256. In the case of a separate supply and return secondary line, in particular the main line is broken at this point and leads directly to the print head - in other words not the secondary lines, but the main line leads directly to the printheads.

It may also be appropriate, as the case may be, that there is no provision for an entire main line leading around the entire carousel as described in US Pat Fig. 2a but that two or more main lines 250 and 260 are provided, which can supply a certain angular section of the carousel 101 or arranged in this area printing stations or printing segments with printing ink from the ink tank. The structure of the individual main lines and secondary lines 250 and 251-253 or 260 and 261-263 is analogous to those in Fig. 2a have been described. However, a shorter choice of main lines may favor the creation of certain pressure conditions in the lines. For this purpose, a respective flow pump 281 or 283 and a return pump 282 or 284 are respectively provided on the respective main lines 250 and 260.

Contrary to the comments on Fig. 2a and 2b shows Fig. 1 an embodiment in which lead separate leads from the ink tank to each individual printing segment of a printing station. In this embodiment, it is necessary that a flow and a return pump are attached to the respective supply lines, so that on the "way out" ink can be conveyed from the ink tank to the respective printing station and on the "return" ink from the printing station or the respective printing module or printing segment can be transported back into the ink tank.

However, all embodiments have in common that it is advantageous if a pressure difference between the flow pump and the return pump exists such that at least a slight negative pressure is applied to the pressure nozzles of each pressure module. This is achieved by the pump power of the return pump or the return pumps is higher than the pumping line of the flow pumps at any time. Thus, unwanted dripping of ink from the individual printing nozzles, which could lead to sticking of the printing nozzles, can be avoided. It is also advantageous if the pump power of the flow pump is adjustable, for example, to ensure a constant pressure in the main and secondary lines. For this purpose, the pumping power of the flow pump can be adjusted so that it can be set as a function of, for example, the rotational speed of the carousel and / or in dependence on the fill level of the respective ink tank.

While the main lines in the Fig. 1 and 2a It is particularly advantageous if the line leading from the ink tank engages the underside of the ink tank and the line leading back into the ink tank is arranged on the top side of the ink tank. The underside of the ink tank is the side that is closer to the center of the earth or to the surface or the floor on which the direct printing press is placed.

In order to keep the resulting ink paths as low as possible, which considerably facilitates the maintenance of a certain pressure level in the lines, it is provided according to an embodiment that the entire ink supply system is arranged directly in the carousel.

Fig. 3 shows an embodiment of a printing station 110 of the direct printing machine 100, as shown in FIG Fig. 1 is shown. In this embodiment, four printing modules 331-334 are associated with each printing segment. In this case, the printing segment 330 and the corresponding printing modules 331-334 may be formed to print the container surface in different colors. This means that the individual printing modules are each connected via lines 311-314 with pairs of different ink tanks, so that each printing module applies a different color from the other printing modules on the surface of the container. However, this is not absolutely necessary. Thus, each printing module can apply the same color, for example black or blue, to the surface of the container. In this case, each printing module for the application of the printing ink in a different area from the rest of the printing module be provided or each printing module can cause the application of a specific motif. Additionally is in Fig. 3 a centering device is provided which comprises a centering bell 371 and a stand or turntable 372 associated with this centering bell. By means of this centering device, the container shown in dashed lines can be clamped and fixed and optionally rotated about its longitudinal axis or, for example, moved up and down parallel to its longitudinal axis. The rotary drive can also be moved into the centering bell 371 to dispense with the turntable 372 and the lower receptacle and to receive the container suspended in the centering (for example, via a mounted on the centering bracket, which at a further part of the mouth region of Container (eg support ring) attacks).

It is preferred if the arrangement of the pressure segment 330 of the individual printing modules 331-334 is provided independently of the centering device, so that these are two separate assemblies. In a corresponding embodiment, it is particularly preferred if the printing segment 330 as a whole or each of the printing modules 331-334 is removably provided in the printing station 110. In particular, quick-change connections to the lines 311-314 can facilitate uncomplicated replacement or removal and insertion of printing modules 331-334. In particular, for this purpose, self-sealing couplings can be provided on each line, which self-close upon release, so that no ink can run out.

Fig. 4 shows another embodiment of a printing segment 430. In this embodiment, the printing segment 430 is provided as a kind of frame on which the printing modules 431-433 are arranged. This frame can be a frame in which the printing modules can be clicked or screwed, for example. Preferably, the entire pressure segment via connections 481 and 482, such as plug or screw, connected to the carousel 101, so that it can be removed as a whole from the carousel. An additional expansion of individual printing modules 431-433 is advantageous.

The individual printing modules 431-433 are connected to the ink tank 102 via the respective leads 411-413. In this embodiment, it is provided that the ink tank is subdivided into three separate individual tanks 421-423 which are each connected to only one supply line 411-413. In the supply lines, a derivative can be integrated - depending on whether a vacuum on the printhead 411-413 is needed. Incidentally, this applies to all embodiments. The ink tanks are arranged concentrically in this embodiment, one above the other parallel to the rotational axis of the carousel. While they seemingly similar in the presentation Having sizes, of course, depending on the necessary ink requirements for the individual printing modules, a respectively adapted ink tank can be used with a corresponding filling volume.

While the printing modules 431-433 are arranged closer to the rotation axis R of the carousel at the pressure segment 430 than the container 490 clamped in the centering device, in another embodiment it is also conceivable that the pressure modules on the opposite side of the container 490, ie further away from the rotational axis of the carousel than the clamped container. As a result, more space is gained in the direction of rotation of the carousel for the individual printing modules and supply lines, so that, for example, more printing modules can be arranged in each individual printing segment.

Fig. 5 shows a further embodiment of a direct printing machine 500 according to the invention. Again, the ink tanks 502 and 503 are arranged concentrically and one above the other with respect to the rotational axis R of the carousel. However, if the fill level of the ink tanks is eventually exhausted, it is necessary to refill them. Since an expansion and replacement of the ink tanks would be cumbersome, it is advantageous if 500 refill connections are arranged on the outer periphery of the direct printing machine. This Nachfüllanschlüsse can be arranged for example in the stationary part of the direct printing machine and lead via a corresponding line and a rotary distributor up to the mitbewegten ink tanks. This would make it possible to fill ink tanks 502 and 503 even when the direct printing machine is in operation. However, this is not recommended for reasons of safety at work. In addition, there is the problem of connection via the rotary distributor and optionally long transport paths for the refilled ink. It is therefore envisaged that according to the in Fig. 5 illustrated embodiment, one or more refill ports 520 and 530 between two adjacent printing stations 110 and 110 'are arranged. These Nachfüllanschlüsse are accordingly mitdrehend connected to the carousel and lead via co-rotating lines 521 and 531 in the respective tanks 502 and 503. Here, the lines 521 and 531 need not be directly connected to the corresponding ink tanks 502 and 503, but can, for example, with a main, as in the Fig. 2a and / or 2b. In such a case, due to the vacuum applied according to the invention, due to the higher pumping capacity of the return pump compared with the supply pump, direct transport of the ink from the replenishment connections into the tanks 502 and 503 would take place. However, if the refill ports 520 and 530 are connected directly to the tanks 502 and 503 via the lines 521 and 531, it may be advantageous if a corresponding pump is arranged in the lines, the pumping direction of which runs in the direction of the tanks.

In the Fig. 5 illustrated embodiment shows two refill ports 520 and 530, which are arranged together between the two printing stations 110 and 110 '. It is of course also conceivable that more than one refill port is provided for one and the same ink tank, for example 502 or 503, the corresponding refill connections then being able to be evenly distributed on the circumference of the carousel of the direct printing machine 500, for example. Since such machines are usually not accessible from all sides, it can be ensured that at least one of the ports can be reached at refill of the direct printing machine after only a slight rotation (if any) of the carousel for refilling. For example, it can be provided that at least one of the refill connections comes to a stop in the region of an opening of a panel of the direct printing machine 100, so that an operator can refill the ink tanks through this opening. In particular, the ports 520 and 521 are provided as couplings in which a hose or a cartridge with matching counterpart can be docked. In the simplest case, however, they are funnel-shaped connections into which the ink can be poured from above (not shown).

Fig. 6a and 6b show further advantageous embodiments of the individual printing stations or printing segments. In the execution according to Fig. 6a a pressure module of a pressure segment is shown. The printing module 111 comprises a plurality of printing nozzles 611, which can print on a container 130. If several printing modules are used in a printing segment of a printing station, there is a risk that despite the applied negative pressure by the return pump, as in Fig. 2a and 2b described unintentionally when printing the container 130 drops of ink or resulting mist on opposite or adjacent pressure modules meet, for example by the wind during rapid rotation of the carousel. This can lead to contamination of the printing nozzles, which at worst can significantly affect the quality of the printed image, as mixed, for example, different inks. Even with the provision of a curing device such as a UV lamp in the printing segment (as an additional module), the printing modules can be adversely affected because, for example, ink can stick or dry on the printing nozzles. To avoid this problem, shields 690 can be provided for each printing module, which can be moved in front of the relevant printing module 111 and in particular in front of the printing nozzles 611 when the printing module is not in operation. The method of the shield 690 can be carried out laterally from the printing module 111 to the printing nozzles 611 (in particular in the horizontal direction) or the shield 690 can be positioned in the non-shielding state above or below the printing module and then moved in front of the printing nozzles 611. The latter embodiment has the advantage that no space is left for the shielding in the printing plane must be so that several printing modules can be arranged side by side.

Fig. 6b shows an alternative embodiment, wherein here no separate shield for each printing module is provided but the container is inserted into a shield 695. This shield may, for example, as shown, be designed as a cylinder and should be rotatable at least about an axis parallel to the longitudinal axis L of the container 130. The shield 695 includes an opening 696 that is at least large enough for ink jets of a print module 111 'to fully penetrate the opening and apply a print image to the container. For this purpose, when the printing module 111 'is to print on the container, the shield 695 is rotated so that the opening 696 points in the direction of the printing nozzles 611. Since the shield 695 must be larger than the container 130, so the splash of ink drops, which could possibly meet other printing modules 111, can be avoided. In addition, a UV light source placed in the same plane is shielded. This effect can be further supported by the fact that the printing module 111 'is moved closer to the opening 690 and thus to the container surface during the printing process, so that optionally the pressure nozzle row is even within the imaginary full cylinder jacket of the shield 695, whereby accidental spraying of Ink can be completely or almost completely suppressed on other printing modules.

Claims (15)

1. Direct printing machine (100) for printing on containers (130) such as bottles, comprising a carousel (101) with a plurality of printing stations (110) which can receive and print on a container, wherein an ink supply system (103) comprising at least one ink tank (102) and at least one supply line (131-13n) which can supply ink from the ink tank (102) to at least one of the printing stations (110) is arranged on the direct printing machine (100) to co-rotate with the carousel (101), wherein the machine is designed without an ink rotary distributor, characterized in that a stationary tank is provided with a port which can only be connected to the direct printing machine at a standstill of the direct printing machine, wherein the stationary tank can be connected to the ink tank (102) via a refill port (520, 530) which is connected to the ink tank (102) and is arranged on the circumference of the carousel.
2. Direct printing machine (100) according to claim 1, characterized in that each printing station (110) comprises a printing segment (330) which contains at least one printing module (331-334) and is detachably connected to the printing station (110), wherein a connection of the printing module (331-334) to a supply line (311-314) exists in the installed state.
3. Direct printing machine according to claim 2, characterized in that each printing station (110) comprises a container receptacle, wherein the container receptacle and the printing segment (330) are designed as separate components or as one component.
4. Direct printing machine according to claim 2 or 3, characterized in that the printing segment (330) comprises a plurality of printing modules (331-334) arranged concentrically about the longitudinal axis of a container located in the printing station (110).
5. Direct printing machine according to any of claims 1 to 4, characterized in that each printing module (111) is associated with a shield (690) which can be moved between a rest position and a shield position in which the shield (690) shields printing nozzles (611) of the printing module (111).
6. Direct printing machine according to any of claims 1 to 5, characterized in that the ink supply system further comprises at least one controllable feed pump (281) for pumping ink from the ink tank (102) to the printing stations and at least one return pump (282) for pumping ink from the printing stations into the ink tank (102).
7. Direct printing machine according to any of claims 1 to 6, characterized in that the supply line comprises at least one main line (205) for transporting ink from the ink tank (102), the line extending along at least a part of the circumference of the carousel (101), wherein one or more secondary lines (251-258) lead from the main line (205) to the printing stations (251-258) and at least one discharge line leads from each of the printing stations to the main line (205), wherein ink can be discharged from the ink tank (102) via a first port of the main line (205) to the ink tank (102) and can be introduced into the ink tank (102) via a second port of the main line (205).
8. Direct printing machine according to any of claims 1 to 7, characterized in that a plurality of ink tanks are provided, wherein separate supply lines are assigned to each ink tank, wherein the ink tanks are arranged either concentrically about an axis of rotation of the carousel or one above the other parallel to the axis of rotation of the carousel or not concentrically distributed.
9. Direct printing machine according to any of claims 1 to 8, characterized in that the ink supply system is arranged in the carousel.
10. Direct printing machine according to any of claims 1 to 9, characterized in that the refill port (520, 530) is arranged between two adjacent printing stations (110, 110').
11. Method for printing on containers such as bottles by means of a direct printing machine (100), wherein the containers are received and printed on by printing stations (110) on a rotating carousel (101), wherein an ink supply system (103) co-rotating with the carousel supplies ink from an ink tank (102) to at least one of the printing stations (110) via a supply line (131-13n), wherein the direct printing machine is a direct printing machine designed without an ink rotary distributor, characterized in that a stationary tank is provided with a port which is connected to the direct printing machine only at a standstill of the direct printing machine, wherein the stationary tank is connected to the ink tank (102) via a refill port (520, 530), which is connected to the ink tank (102) and is arranged on the circumference of the carousel, for refilling the ink tank (102).
12. Method according to claim 11, characterized in that ink is pumped from the ink tank (102) into the supply line via a controllable feed pump (281) and ink is pumped back into the ink tank via a return pump (282), wherein the pumping capacity of the return pump is higher than the pumping capacity of the feed pump at all times, so that a negative pressure is applied to printing nozzles of the printing station.
13. Method according to claim 12, characterized in that the pumping capacity of the feed pump is controlled as a function of the filling level of the ink tank (102) and/or as a function of the rotational speed of the carousel (101).
14. Method according to any of claims 11 to 13, characterized in that ink can be supplied to the ink tank (502, 503) via the refill port (520, 530), wherein the refill port (520, 530) is arranged between two adjacent printing stations (110, 110') and, when refilling of the ink tank is necessary, the carousel is brought to a standstill in a position in which the refill port is accessible from outside the direct printing machine.
15. Method according to any one of claims 11 to 14, characterized in that ink is transported from the ink tank (102) along a main line (205) and is supplied to individual printing stations (251-258) via secondary lines (251-258) and is passed from the printing stations into the main line via discharge lines, wherein the ink is passed from the ink tank (102) into the main line (205) via a first port of the main line (205) and is passed from the main line (205) into the ink tank (102) via a second port of the main line (205).

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