Title of Invention	DEVICE AND METHOD FOR PRINTING CONTAINERS
Abstract	The invention relates to a device and a method for printing containers, especially in multiple colours, on at least one outer surface of the container, using a print formed by at least one printed image, at least one printing group provided with print heads operating according to the ink jet printing principle, for producing partial printed images of the printed image to be applied to the outer surface of the container in at least one printing step, and a transport element for moving the container during the printing in a transport direction. The printing groups are moved with the transport element at least one printing step.

Title of Invention

DEVICE AND METHOD FOR PRINTING CONTAINERS

Abstract

The invention relates to a device and a method for printing containers, especially in multiple colours, on at least one outer surface of the container, using a print formed by at least one printed image, at least one printing group provided with print heads operating according to the ink jet printing principle, for producing partial printed images of the printed image to be applied to the outer surface of the container in at least one printing step, and a transport element for moving the container during the printing in a transport direction. The printing groups are moved with the transport element at least one printing step.

Full Text	Device and method for printing containers The invention relates to a device in accordance with the preamble of Claim 1, 30 or 31 and to a method in accordance with the preamble of Claim 41, 57 or 59 and in this case especially to a device or respectively a method for applying a print, preferably in multiple colours, directly onto the outer surfaces of containers. Containers in terms of the invention are, in particular, packaging means, in the form of containers, for the most varied types of liquid products and in this case, in particular, also bottles or bottle-type containers or cans or can-like containers. Printing inks in terms of the invention are those colours or inks, in particular, in lightly viscous liquid form that can be processed with print heads that are digitally actuatable and operate according to the ink jet print head principle. Consequently, print heads in terms of the invention are, in particular, print heads that have a plurality of print nozzles for discharging the printing ink, for example in at least one row, and that are individually actuatable for discharging the printing ink and, for this purpose, have a print generating element at the respective nozzle opening, for example in the form of an electrode of a piezo element. Devices for printing containers by using print heads that operate according to the ink jet print head principle and with relative movement between the print heads and the respective containers are known. In the case of a known device (WO 2004/009360), during the printing process the containers are each positioned on a mandrel in the form of a container support. A plurality of print heads are provided distributed about the mandrel, with which print heads, when the mandrel is rotated, a coloured printed image, consisting of a plurality of colour sets, is applied to the respective container. The mandrels are provided on a rotatably driven transport element, with which, during the printing, the containers are moved on a transport section formed between a container inlet and a container outlet. It is the object of the invention to provide a device with which, at high output, it is possible to print containers with a high-quality print formed by at least one printed image. A device according to Claim 1, 30 or 31 is realized to achieve this object. A method for printing containers is the object of Claim 41, 57 or 59. In the case of the invention, the containers are printed on their outside surfaces by applying the printing ink with the print heads directly onto the outer surface of the container or with a transfer print method by using transfer elements or transfer pads onto which the respective printed image is applied with the print heads and is then transferred onto the containers. Further developments, advantages and application possibilities of the invention are produced from the following description of exemplary embodiments and from the Figures. In this case, all described and/all graphically represented features, individually on their own or in arbitrary combination, are in principle objects of the invention, independent of their summary in the claims or their dependency. The content of the claims is also made part of the description. The invention is described in more detail below by way of the Figures of examples of devices for printing containers in multiple colours on an outer surface of the container that is realized in a rotationally-symmetrical manner about a container axis, for example on an outer surface of a container that is cone-like or in the shape of a circular cylinder, in which, in detail: Figures 1 and 2 show a schematic, perspective representation and a top view of the device according to the invention; Figure 3 shows a partial representation of a top view of a rotor of the device in Figures 1 and 2, said rotor being rotatably driveable about a vertical machine axis; Figures 4-6 show representations as in Figures 1 - 3 of an additional specific embodiment of the invention; Figures 7 and 8 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figure 9 shows a top view of a part representation of the transport system of the device in Figures 7 and 8 with the printing groups; Figures 10 and 11 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figure 12 shows a part representation and top view of the rotor, in different positions, together with a printing unit that includes a plurality of print head elements in different operating states, said rotor being rotatably driveable about the vertical machine axis; Figure 13 and 14 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figure 15 shows a part representation of the conveyor in Figures 13 and 14, in different positions, together with a printing unit that includes a plurality of print head elements in various operating states; Figures 16 and 17 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figures 18 and 19 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figures 20 and 21 show a schematic, perspective representation and top view of another specific embodiment of the device according to the invention; Figure 22 shows, shows a schematic representation and part representation in each case, of different operating states of the device in Figures 20 and 21, in various positions. In Figures 1 - 3 the reference 1 is given to a device for printing containers 2 in multiple colours on their outer or outside surface and, in this case, preferably on a region of the container outside surface that is realized in a rotationally- symmetrical manner with reference to the container axis, for example on a circular cylindrically shaped or frustum-shaped or substantially circular cylindrically shaped or frustum-shaped region of the outer surface of the container. The containers 2 are supplied to the device 1 by means of a conveyor, identified schematically in the Figures by the reference 3, standing upright, i.e. oriented with their container axes in the vertical direction and in a single-track container flow in the direction of transport specified by the arrow T and after they pass a corona tunnel 4 and a separating screw 5 they reach a rotor 7 of the device 1. At the periphery of the rotor 7, which is rotatably driveable about a vertical machine axis MA in the direction of the arrow R, printing stations 8 are formed at regular angular spacings offset about said machine axis, said printing stations comprising in each case substantially a container support 9, in the form of a turntable that is rotatable in a controlled manner about an axis parallel to the machine axis, a printing group 10 and a device 11 for drying and/or setting the printing ink. Each printing group 10, in the specific embodiment represented, includes four print heads. 10.1 - 10.4 for generating various colour sets of a multiple colour print or printed image and another print head 10.5 for flat printing or applying a transparent sealing or protective coating, for example a covering finish onto the printed image generated with the print heads 10.1 - 10.4. The print heads 10.1 - 10.4 are digitally actuatable print heads of the ink jet print head type, for example print heads that can be obtained commercially under the reference "XAAR" or "Xaar500". The print heads 10.1 - 10.5 each comprise, correspondingly, a housing with a plurality of individually actuatable print nozzles for discharging the printing ink in the distribution and quantity corresponding to the respective printed image or colour set on the background to be printed on , i.e. in the present case onto the outer surface of the container to be printed on. The print nozzles, oriented with their axes horizontally or substantially horizontally, are positioned on each print head 10.2 -10.5 in at least one row parallel or substantially parallel to the vertical machine axis MA. The discharging of the printing ink is achieved, for example, through corresponding actuation of electrodes or of piezo elements in the print heads 10.1 -10.5, for example at an actuating frequency of up to 50 kHz and a relative movement between the respective print head and the surface to be printed of 560 mm/second. The number of print nozzles per print head is, for example, in the range of 500 with a print width of approximately 70 mm. The print heads 10.1 - 10.4 include colour printing ink in different colours, namely in yellow, magenta, cyan and black. As shown in Figures 1 - 3, the print heads 10.1 - 10.5 of all the printing stations 8 are positioned on a common circular line surrounding the machine axis MA in such a manner that the print heads of all the printing groups 10 entrained with the rotating rotor 7 are situated, with reference to the machine axis MA, inside a circular path on which the container supports 9 move. The print nozzles of all the print heads 10.1 - 10.5, consequently, with reference to the machine axis MA, are aligned with their axes constantly radially outwards such that the discharging of the printing ink onto the containers 2 is supported by the centrifugal force when the rotor 7 is rotating. The printing group 10 of each printing station 8, as detailed, is realized in a rotating manner with the rotor 7, however, for the print head change, is at the same time pivotable about the machine axis MA in a successive manner or is switchable further in the direction of rotation of the rotor and in opposition to said direction of rotation such that when a container 2 is being printed, each print head 10.1 -10.5 can be moved at least once into a printing position in which the relevant print head with its print nozzles is directly adjacent the container 2 standing upright on the container support 9 with a small distance in between (e.g. less than 1 mm). The device 11, which performs the drying of the printing ink through an application of energy or heat and/or UV radiation, is provided about the axis of the respective container support 9 offset by approximately 90° relative to the printing group 10. With the device 1, the devices 11 are positioned on a common circular line surrounding the machine axis MA, the radius of said circular line being identical or substantially identical to the distance between the axes of the container supports 9 and said machine axis MA, in such a manner that in the direction of rotation R of the rotor the respective device 11 is ahead of the associated container support 9. For the printing, the containers 2 are transferred in each case individually via the transport star 6 to a printing station 8, at which, with a controlled rotational movement of the container support 9 and consequently with a controlled rotational movement of the containers 2 about their container axes, one after the other the colour sets forming the colour print are printed with the print heads 10.1 - 10.4 and then the protective coating is applied with the print head 10.5. In detail, the printing of each container is effected such that, after the transfer to a printing station 8, the colour set corresponding to the print head or the final protective coating are printed onto the outer surface of the container with the print heads 10.1 - 10.5 each switched into the printing position, and during the printing of each colour set and possibly also even during the switching further of the printing group 10 by a print head spacing or by a print head, the drying of the applied printing ink is performed by means of the device 11. During each printing step, i.e. during the printing of the respective colour set or the applying of the protective coating and the drying of the printing ink or of the protective coating, each container 2 is rotated by 360°. Each printing step with the drying is effected for example on an angular region of the rotational movement of the rotor 7 of ca. 50° such that the printing of the containers 2 is completed reliably before the containers 2 reach a container outlet at which they are discharged via a transport star 12 on a conveyor 13. The resetting of the printing groups 10 into the initial position is effected in the angular region of the rotational movement of the rotor 7 between the transport stars 12 and 6. An improved or sharper printed image is achieved through the treatment in the corona tunnel by charging the containers 2 electrostatically on their outer surface. An optoelectric control system 14 is provided in the direction of rotation R of the rotor directly before the transport star 12, by means of which control system the print on the containers 2, which are moved past said system and are rotated further about the container axis, is checked so that containers with a faulty print can be discharged on the conveyor 13. Figures 4-6 show, in the form of another specific embodiment, a device 1a which only differs substantially from the device 1 in that at the individual printing stations 8 instead of the printing groups 10, printing groups 10a are provided that have the print heads 10.1 - 10.5 at a support 15, which can be switched further for the print head change by rotating about an axis parallel to the machine axis MA. The print heads 10.1 - 10.5 are provided distributed at regular angular distances on the periphery of the support 15. The supports 15 are situated, in their turn, inside the path of movement of the container supports 9 such that each print head moved into the printing position, i.e. positioned directly adjacent the container 2 to be printed,- is aligned with its print nozzles radially outwards with reference to the machine axis MA. The printing of the containers 2 is effected, in the case of the device 1 a, once again onto the angular region of the rotational movement of the rotor 7 between the transport star 6 and the control system 14, the corresponding print head being switched into the printing position for each colour set and for the sealing or protective coating. The printing ink or the sealing or protective coating is dried by means of the device 11 during the printing. The respective container 2 is rotated by 360° during the printing steps (applying the colour sets, the sealing or protective coating and the drying). Figures 7 and 8 show, in the form of another embodiment, a device 1b which only differs substantially from the device 1 in that instead of the rotor 7, there is provided a transport system 16, which on at least one transport element, which forms a closed loop and is driveable in an endlessly circulating manner, has a plurality of printing stations 8 at regular spacings, each with a container support 9, a printing group 10 and a device for drying the printing ink. The containers 2 are supplied to the device 1a once again via the transport star 3 with the corona tunnel 4 and are transferred in each case individually via the transport start 6 to a printing station 8, with which the respective container 2 is then moved during the printing in the direction of transport TS on the transport section 17 of the transport system 16. The printed containers 2 are forwarded to the conveyor 13 with the transport star 12 that forms a container outlet. The printing of the containers 2 with the individual printing inks or colour sets of the multi-coloured print and the applying of the sealing or protective coating is effected analogously to the description given in conjunction with the device 1. For this purpose, the printing groups 10, entrained with the transport system 16 or their print heads 10.1 - 10.5 are moveable or switchable for the print head change relative to the transport system 16 in the direction of transport TS and in opposition to said direction of transport and are situated on the inside of the loop formed by the transport system 16. The devices 11 of all the printing stations 8 are positioned on a common loop line which also intersects the vertical axes of rotation of the container supports 9, the container supports 9 being ahead of the associated device 11 in each case in the direction of transport TS. In detail, the printing of the containers 2 is effected once again in such a manner that by switching further the print heads 10.1 - 10.5, the respective colour set or the sealing or protective coating are applied, and during the printing process, possibly also still during the switching further of the print heads, the drying of the printing ink and the sealing or protective coating is effected by means of the associated device 11, the respective container with the container support 9 being rotated by 360°. Figures 10-12 also show, in the form of another embodiment of the invention, a device 1c for printing containers 2 in multiple colours. The device 1c differs from the device 1 in that a plurality of container supports 9 is provided on the periphery of the rotor 7 at regular angular spacings about the vertical machine axis MA, however, said container supports 9 are not components of the printing stations each with independent printing groups. In the case of the device 1c, one single printing group or unit 18 is in fact provided with a plurality of print head units 18.1 - 18.5, each unit of which having a plurality of print heads 19, in the specific embodiment represented two print heads in each case. The print heads 19 are realized in the same manner as the print heads 10.1 - 10.5. Each print head unit 18.1 - 18.5 or its print heads 19 serve in the manner described in more detail below for simultaneously discharging the colour sets of a colour associated with the respective print head unit or the sealing or protective coating onto a number of containers 2 corresponding to the number of print heads 19, i.e. in the case of the specific embodiment represented for simultaneously discharging onto two containers 2. The print head units 18.1 - 18.5 are also each realized with two devices 20 that can be switched on or off for drying the respective print or the printing ink, for example by the application of energy, e.g. by heating and/or UV light, in each case one device 20 being associated with one print head 19. The print head units 18.1 - 18.5 with their print heads 19 and their devices 20 are positioned on a common support 21, which can be moved or pivoted back and forth about the machine axis MA by a stroke that corresponds to a machine spacing, as is indicated in particular in Figure 12 with the arrows TR1 and TR2. The print unit 18 formed by the print head units 18.1 - 18.5 and the support 21 is therefore floating. It is situated, with reference to the machine axis MA, inside the path of movement on which the container supports 9 move when the rotor 7 rotates. In addition, the individual print heads 19 are positioned such that they point radially outwards with their print nozzles, each positioned in a row parallel or substantially parallel to the machine axis MA, with reference to said machine axis, such that the discharging of the printing ink is once again supported by the centrifugal force when the rotor 7 is rotating. The arrangement is also such that the spacing between the print heads 19 on each print head unit 18.1 - 18.5, but also the spacing between adjacent print heads 19 on print head units 18.1 -18.5 following one another in the circumferential direction of the rotor 7 is identical to the angular spacing between two adjacent container supports 9. In addition, the devices 20 in the activated or switched-on state, seen in a top view of the rotor 7, are offset by 90° relative to the print heads and are positioned on a circular line that surrounds the machine axis MA and also intersects the axes of rotation of the container supports in the direction of rotation R of the rotor ahead of the adjacent container support or the container 2 standing upright on said container support in each case. Each print head unit 18.1 - 18.4 has associated therewith in each case a colour set or a colour, namely yellow, magenta, cyan or black. The print head unit 18.5 or its print heads 19 serve for discharging or printing the sealing or protective coating. The print head units 18.1 - 18.5 are provided following one another in the direction of rotation R of the rotor in order of their reference numbers, i.e. in the direction of rotation R of the rotor the print head unit 18.1 forms the first print head unit of the printing unit 18 and the print head unit 18.5 forms the last print head unit of the printing unit 18. The multi-coloured printing of each container 2 is effected once again in several chronological printing steps in which the printing, i.e. discharging the relevant colour set or the sealing or protective coating and the drying is effected with the containers 2 rotating about the container axes, for example rotating about 360°. The individual printing steps are executed at each container chronologically one after the other by the print head units 18.1 - 18.5, with each print head unit 18.1 - 18.5 at two containers simultaneously in each case. During each printing step, the printing unit 18 is entrained in the same direction and in a synchronous manner with the rotor 7 (arrow TR1). The devices 20, in this case, are delivered and activated so that the drying of the generated colour sets is also effected during each printing step. After the completion of each printing step and before the introduction of a new printing step, the printing unit 18 is pivoted back, with devices 20 retracted, in opposition to the direction of rotation R of the rotor by the machine spacing into the initial position (arrowTR2), in which then, on account of the rotational movement of the rotor 7, an unprinted container 2 in each case is adjacent the print heads 19 of the print head unit 18.1 and a container 2 in each case that has already been printed in a previous printing step by the print heads 18.1 - 18.4 is adjacent the print heads 19 of the print head units 18.2-18.5 for another printing step. In the next printing step, the floating printing unit 18 is then entrained again in the same direction and in a synchronous manner with the rotational movement of the rotor 7 by the machine spacing (arrow TR1) and after completion of this printing step is pivoted back by the machine spacing into the original position (arrow TR2). The machine spacing, in this case, is twice the spacing between two container supports 9. The printing of the containers 2 in multiple colours is completed before said containers 2 reach the transport star 12 that forms the container outlet, so that, also in the case of the device 1c, a control system 14, for example an optoelectric control system is provided in the direction of rotation R of the rotor before the transport star 12 for checking the respective print on the containers 2 moved past said system and being rotated at the same time so that containers 2 with missing or faulty print can subsequently be discharged onto the conveyor 13. Figures 13-15 show, in the form of another embodiment, a device 1 d which differs in the first instance from the device 1c in that instead of the rotor 7 a transport system 16 is provided that forms a closed loop and is driven in an endlessly circulating manner. The container supports 9 are provided on said transport system 16. In addition, at the transport section 17 of the transport system 16 on which the printing of the containers 2 in multiple colours is effected, there is provided a printing unit 18a, which comprises a plurality of print head units, namely a total of six print head units 18.1 - 18.6, three of which print head units 18.1 - 18.3 or 18.4 - 18.6 are positioned in each case on each side of the transport section 17. The transport system 16 has the container supports 9 at regular spacings. The print head units 18.1 - 18.6 are realized in the identical manner as described for the device 1c for the print head units 18.1 -18.5 used there, i.e. each print head unit 18.1 - 18.6 has two print heads 19 spaced apart by half the machine spacing and two devices 20 also spaced apart by half the machine spacing. In addition, the print heads 19 and devices 20 of print head units 18.1 - 18.3 or 18.4 - 18.6 adjacent one side of the transport section 17 are each spaced apart by half the machine spacing. The printing unit 18a or the print head units 18.1 - 18.6 positioned on a support (not shown) are moveable by a drive (not shown) in a synchronous manner and in the same direction with the movement of the transport system 16 out of an initial position in the direction of transport TS by the machine spacing and in opposition to the direction of transport TS back into the initial position, said floating movement also being synchronized with the movement of the transport system 16 in such a manner that after the movement back into the initial position, each print head 19 with its printing nozzles is once again situated directly opposite a container support 9 or a container 2 at that location. The containers 2 to be printed are supplied to the device 1d by means of the conveyor 3 with the corona tunnel 4 and are transferred in each case individually to a container support 9 by means of the transport star 6. Once the containers 2 have been printed on the transport section 17, the printed containers are removed from the container supports 9 by means of the transport star 12 and are forwarded to the conveyor 13. The printing of the containers 2 is once again executed in several chronological printing steps, in each printing step a number of containers 2 that corresponds to the number of print heads 19 of the print head units 18.1 - 18.6, i.e. in the case of the device 1d in each case two containers 2 being printed simultaneously with the two different colours associated with the print head units (at the print head units 18.1/18.4, 18.2/18.5) or with the finish that forms the sealing or protective coating and a printing ink (at the print head units 18.3/18.6). During each printing step the print heads 19 of the print head units 18.1 - 18.6 are adjacent a container 2. The printing is carried out by rotating the containers 2, for example, by 360° with the devices 20 activated such that the printing ink applied with one print head 19 is dried by the device 20 following said print head in the direction of rotation of the respective container 2 before a printing ink or finish is applied once again in the same printing step by the other print head 19. During each printing step the printing unit 18a is entrained in the same direction and in a synchronous manner with the transport unit. At the end of the printing step the printing unit 18a is moved back into the initial position so that in another printing step a print application can then be effected with the print head units 18.1 and 18.4 onto still unprinted containers 2 in each case and a print application can be effected with the print head units 18.2, 18.3 and 18.5, 18.6 onto such containers 2 that have already been printed in a previous printing step with the print head units 18.1, 18.4 or 18.2, 18.5. Whereas, in the case of the abovementioned devices 1 - 1 d, the printing of the containers 2 in multiple colours on their container outer surface is effected directly with the printing groups or their print heads, Figures 16 and 17 show a device 1e for printing containers 2 in multiple colours in a transfer print. The printing in multiple colours is once again effected on the container outer surface or container outside surface and in this case preferably, with regard to the container axis, on a rotationally symmetrically realized region of the container outer surface, for example on a circular cylindrical-shaped or frustum-shaped region of the container outer surface. By means of a conveyor, which is schematically represented in Figures 16 and 17 and identified with the reference 30, the containers 2 are supplied to the device 1e in the direction of transport specified by the arrow T, standing upright and in a single-track container flow, and having passed a corona tunnel 31 provided on the conveyor 30 and a separating screw 32 they reach a rotor or turntable 34 of the device 1e by means of a transport star 33. At the rotor 34 the containers 2 are retained so as to be rotatable about their container axes at container supports provided at that location (not shown) and are moved during the printing with the rotor 34 on a circular transport section. The printed containers are removed from the rotor 34 by a transport star 35 and are forwarded to a conveyor 36. The printing of the containers 2 in multiple colours is effected by using transfer pads 37, which are provided on the periphery of a transfer drum 38, which is rotatably driveable about the machine axis MA in the direction of rotation R of the rotor but at a speed that is increased compared to the rotational speed of the rotor 34. The transfer pads 37 are provided at the transfer drum 38 so as to be adjustable radially relative to the machine axis MA between a switched-on position located radially further outside and a switched-back position located radially further inside. In addition, the transfer pads 37 are positioned such that they move with their outer face, curved in an arcuate manner about the machine axis MA, inside the circular path of movement of the containers 2 or of the container supports between the transport stars 33 and 35. A printing group 39 is provided in the direction of rotation R of the rotor 34 or of the transfer drum 38 upstream of the transport star 33, with which printing group the printed image to be discharged onto the container 2 is applied to the outer face of the transfer pad 37. The printing group 39 comprises a plurality of print heads 39.1 - 39.4 following one another in the direction of rotation R of the rotor for different colours, for example for yellow, magenta, cyan and black or for generating the various colour sets. The print heads 31.1 - 31.4 are digitally controllable print heads of the ink jet print head type, for example print heads that are commercially available under the name "XAAR" or "Xaar500". The print heads 31.1 - 31.4 each comprise accordingly a housing with a plurality of individually actuatable print nozzles or nozzle openings for discharging printing ink in the distribution and quantity corresponding to the respective printed image or colour print onto the background to be printed, i.e. in the present case onto the outside surface to be printed of each transfer pad moved past the printing group 39. The printing nozzles positioned with their axes horizontally or substantially horizontally are positioned at each print head 39.1 - 39.4 in at least one row parallel or substantially parallel to the vertical machine axis MA. The discharging of the printing ink is achieved through corresponding actuation of electrodes or of piezo elements or actuators in the print heads, for example at an actuating frequency up to 50 kHz and a relative movement between the respective print head and the surface of a transfer pad to be printed of ca. 560 mm/second. The number of print nozzles per print head, for example, is in the range of 500 with a print width of 70 mm. The print heads 39.1 - 39.4 include printing inks each in different colours, namely yellow, magenta, cyan and black. In the direction of rotation R of the rotor upstream of the printing group 39 there is a cleaning station 40, for example in the form of a cleaning roller, by means of which any printing ink or ink residue is removed from the print or transfer pad 37 before a new printed image is applied. At the region of the rotor 34 utilized for printing the containers 2, said region in the specific embodiment represented corresponding to an angular region of approximately 180°, following the inlet star 33 there is provided a device 41 for applying a finish forming a sealing or protective coating on the respective container print, connecting thereto in the direction of rotation R of the rotor a device 42 for drying the container print, including the sealing and protective coating, for example by application of energy, for example heating or UV light and connecting thereto directly in front of the outlet star 35 an optoelectric control system 43, by means of which the printed containers are checked with regard to the quality of the print whilst rotating about their vertical axes so that wrongly printed containers 2 can then be discharged on the conveyor 36. In detail, the printing of the containers 2 is effected with the device 1e in such a manner that the containers 2 transferred individually in each case with the inlet star 33 to the rotor 34 or to the container supports at that location are rolled over by the switched-on transfer pads, provided with the printed images on the outer surface, by reason of the transfer drum 38 that rotates somewhat faster compared to the rotor 34, the containers therefore roll off the transfer pads by rotating about their vertical container axes and consequently the printed image is transferred from the respective transfer pad onto a container 2. As the respective transfer pad 37 is still rolling off, that is still inside the transfer region, the containers 2 are moved past the device 41, by means of which the finish that forms the sealing or protective coating is applied to the respective container, rotating about the container axis in a continuous manner, onto the part of the container print already generated by rolling off the transfer pad 37 on the outer surface of the container. The devices 41 and 42 and the control system 43 are situated with the rotor 34 in a non-entraining manner on the periphery of the path of movement of the containers 2. After the completed transfer of the printed image from the transfer pad 37 onto the outer surface of the relevant container 2 or after the completed rolling off of said container on the relevant transfer pad 37 and after the completed applying of the sealing or protective coating, the relevant transfer pad 37 is switched back and the respective container 2, continuing to be rotated about its container axis, is moved past the device 42 for drying the print and past the control system 43 and finally is discharged with the transport star 35 onto the conveyor 36. After passing the transport star 35, the transfer pads 37 are switched-on once again, i.e. moved radially outwards for the cleaning process at the cleaning station 40 and for the application of a new printed image at the printing group 39. The treatment of the containers 2 in the corona tunnel 31 and the electrostatic charging of the containers 2 at that location produce a substantial improvement in the multi-colour print that is generated with the transfer print onto the outer surfaces of the containers. In a very schematic representation, Figures 18 and 19 show a device 1 f that is once again realized for a transfer print in multiple colours on the outer surfaces of containers 2. In the case of this device, the printing of the containers 2 is effected on a transport system 44 that forms a closed loop and is driven in an endlessly circulating manner or respectively on a substantially linear transport section 45 of said system. Container supports 46 are provided at regular spacings on the transport system 44. The containers 2 to be printed are supplied to the transport section 45 via the conveyor 30 with the corona tunnel 31 and are transferred individually in each case via the transport star 33 to a container support 46, with which the relevant container 2, retained so as to be rotatable about its container axis, is moved during the printing in the direction of transport TS to the transport star 35, by means of which the printed containers 2 are removed from the transport system 44 and forwarded to the conveyor 36. For printing the containers 2 in multiple colours, there is a print device 47 provided at the transport section 45 that includes a plurality of transfer elements or transfer pads 48, which are provided at an auxiliary conveyor 49 so as to be rotating with said auxiliary conveyor, said auxiliary conveyor forming a closed loop. The auxiliary conveyor 49 having the transfer pads 48 forms a vertical loop that is provided with its upper horizontally extending loop length 49.1 parallel to the transport section 45 and directly adjacent to said transport section on one side. In their initial position, the transfer pads 48, which, for example, are substantially rectangular and with their longitudinal extension are oriented in the circumferential direction or in the direction of movement of the auxiliary conveyor 49, are positioned with their surface sides in planes perpendicular to the loop plane of the auxiliary conveyor 49. The auxiliary conveyor 49 is driven in such a manner that its upper length 49.1 moves in the direction of transport TS of the transport section 45, however at a greater speed than the transport section 45. At the upper length 49.1, following one another in the direction of transport TS there is provided a cleaning station 50 in the form of a cleaning roller for removing printing ink residue on the transfer pads 48 and then a printing group 51. The printing group 51 comprises a plurality of print heads 51.1 - 51.5 following one another in the direction of transport TS, said print heads being realized, for example, in an identical manner to the print heads 39.1 - 39.5, however being positioned in such a manner that the print nozzles of said print heads are oriented with their axes in the vertical direction and the rows on each print head formed by the print nozzles are oriented in the horizontal direction perpendicularly or at right angles to the direction of transport TS. The printing group 51, positioned above the path of movement of the transfer pad 48, executes the printing of each transfer pad 46 moved past on the top side positioned in a horizontal plane. After the printing each transfer pad 48 is set up such that with its side that has the printed image, it is positioned in a vertical plane parallel to the direction of transport TS such that the respective container 2 to be printed, being rotated about its container axis, rolls off a transfer pad 48 and in so doing the printed image is transferred from the transfer pad 48 to the outer surface of the container. At the same time a device 52 applies the sealing or protective coating and a device 53 dries the print. The device 1f also offers, among other things, the advantage of it being possible to position the print heads of the print group 51 that operate according to the ink jet print head principle in a position that is optimum for the method of operation, namely with their print nozzles above the path of movement of the transfer pads 48 and with the axes of the print nozzles oriented downwards in the vertical direction. Once the printed image has been transferred, the relevant transfer pad 48 is pivoted back again into its initial position. In a very schematic manner, Figures 20 - 22 show a device 1g that is realized similar to the devices 1, 1a - 1d for printing containers 2 in multiple colours on their outer surfaces by applying the printing ink directly onto the outer surface of the container. In the case of this device, the printing is executed on a transport element in the form of a rotor 54, which is rotatably driven about the vertical machine axis (arrow R) and on which are provided container supports 55, offset from one another at regular angular spacings about the vertical machine axis, for the containers 2 standing upright, i.e. with their container axes oriented in the vertical direction. A ring-shaped print head support 56, which is positioned in an axially identical manner to the machine axis, is provided inside the path of movement of the container supports 55, on said print head support in the same spacing or at the same angular spacing that is between the container supports 55, print heads 57.1 - 57.4 are provided for printing inks in the various colours, namely in yellow (print head 57.1), in magenta (print head 57.2), in cyan (print head 57.3) and black (print head 57.4) along with other print heads 57.5 for applying the coating or protective finish. The print heads 57.1 - 57.5 are each provided in groups on the print head support 56 in such a manner that each group has the print heads 57.1 - 57.5 once and the print heads 57.1 - 57.5 in each group have the same sequence, i.e. for example are provided following one another in the order of their reference numbers in the circumferential direction of the print head support 56, for example in opposition to the direction of rotation R of the rotor 54. The arrangement of the print heads 57.1 - 57.5 is additionally such that in each printing stage (e.g. positions a and c in Figure 22) one print head 57.1 - 57.5 is always situated directly opposite a container 2 or its outside surface in the printing position. In this specific embodiment, the print heads 57.1 - 57.5 together with the print head support 56 form the printing group 57. For printing, the containers 2 are once again supplied to the inlet or transport star 6 via the corona tunnel 4 and the separating screw 5 (arrow T) and are transferred in each case individually from said inlet or transport star to a printing station formed by a container support 55. The printed containers 2 are removed at the outlet or transport star 12 and supplied via the conveyor 13 to another use (arrow T). The container 2 is printed in multiple colours during the transport with the rotor 54 between the inlet star 6 and the outlet star 12. The colour sets forming the respective multi-colour print and the connecting protective coating are applied in each case one after the other with the print heads 57.1 - 57.4 or with the print head 57.5 with the containers 2 being rotated or pivoted in a controlled manner about the container axes with the container supports 55, for example with a controlled rotational movement in each case about 360°. In detail, the printing of each container 2 is executed such that, after being transferred from the inlet star 6 the container 2 is situated opposite a container support 55 in a first angular region of the rotational movement of the rotor 54, i.e. in a first printing stage it is situated opposite a print head for generating a first colour set, for example the print head 57.1 (Figure 22, position a). During this printing stage the print head support 56 is entrained in the same direction and in a synchronous manner with the rotor 54. When the colour set is applied, the container 2 is rotated in a controlled manner about its vertical container axis by 360° and at the same time the printing ink applied in each case is dried by means of a suitable device 58 that is associated with each print head 57.1 - 57.5. The printing stage for applying another colour set or for applying the protective coating that follows the first or in each case another printing stage is introduced by the container support 55 or all the print heads 57.1 - 57.5 being stopped for a short time or being moved by a spacing in opposition to the rotational movement so that the containers "overtake" the print heads 57.1 - 57.5 by a spacing (distance between the print heads) (Figure 22, position b) and thus another print head is situated opposite each container 2 in a printing position, for example, after the print head 57.1 the print head 57.2, after the print head 57.2 the print head 57.3, after the print head 57.3 the print head 57.4 or after the print head 57.4 the print head 57.5. It is obvious that in each printing stage following a previous printing stage that is effected once again on an angular region of the rotational movement of the rotor 54, the print head support 56 or the print heads 57.2 - 57.5 are also entrained with the rotor 54 in a synchronous manner at the identical speed and in the same direction. With rotor 54 the printed containers 2 are moved past a hardening or curing station 59 for complete hardening of the printing ink and of the protective coating and then, connected thereto, before reaching the outlet star 12, are moved past a control station or a control system 14, by means of which the print on the container moved past said system and also rotated about its vertical container axis is checked so that any containers with a faulty print can be discharged on the conveyor 13. In the case of the device 1 g, the number of container supports 55 on the rotor 54 is an integer multiple of the number of print heads 57.1 - 57. 5 in each print head group. Accordingly, the angular spacing or spacing between container support 55 in the case of the device 1g is equal to 3607(n1 x n2), wherein n1 = number of print heads 57.1 - 57. 5 per print head group, namely for example five n2 = number of print head groups on the print head support 56. It has been assumed above that the print head change between two printing stages following one after the other is effected by slowing down the print head support 56 briefly so that the print heads 57.1 - 57.5 are "overtaken" by the containers 2. In principle, a print head change is also obviously possible in the reverse manner by briefly accelerating the print head support 56 in each case so that the container supports 55 or the containers 2 are "overtaken" by the print heads 57.1 - 57.5 during the print head change. In each case, however, the print head support 56 in the printing stage after the print head change and before a new print head change is driven in the same direction and in a synchronous manner with the rotor 54. For reasons of simplicity, the print head support 56 is represented as a ring in Figures 20 - 22. In the embodiment of the device 1g in practice, it is possible for said support to have any arbitrary embodiment that can be used for the function. Thus it is possible, in particular, to realize the print head support 56, for example, in two parts at least, comprising at least one first element that is entrained with the rotor 54 and at least one other guided element, which is provided at said first element and is switchable further for the respective print head change relative to the first element about the vertical machine axis through stepwise rotation by a spacing (distance between the print heads 57.1 - 57.5), for example in opposition to the direction of rotation R of the rotor 54 or in said direction of rotation. The device 1g has, among other things, the advantage that at least the larger part of the angle of the rotational movement of the rotor 54 is available for the printing process, the number of print heads 57.1 - 57.5 can nevertheless be kept relatively small such that the total number of print heads 57.1 - 57.5, for example, is equal to the number of container supports 55, and the respective print head change can be effected through short movement strokes. In the case of the device 1g also, the print heads 57.1 - 57.2 are positioned once again inside the path of movement of the containers 2 on the rotor 54 so that the applying of the printed images or of their colour sets is supported by the centrifugal force of the rotating rotor 54 and print head support 56. The invention has been described above by way of exemplary embodiments. It is obvious that numerous changes and variations are possible without departing from the inventive concept underlying the invention. Thus it has been assumed above that during the printing the containers 2 stand with their container bottom on a container support or on a surface of a rotor or of a transport system. Obviously embodiments are also possible where the containers 2 are retained in another manner during the printing, for example suspended at a container or neck flange provided in the region of the container mouth. It has also been assumed above that the drying of the respective colour set is effected during the printing. In principle, however, it is also possible for the drying not to be effected until the respective colour set has been applied to the outer surface of the container. WE CLAIM 1. Device for printing, in particular for printing containers (2) in multiple colours on at least one outer surface of the container, said device including a print that is formed by at least one printed image, at least one printing group (10, 10a, 18, 18a, 57) with at least two print heads (10.1- 10.5, 18.1-18.6, 19, 19, 57.1-57.5) that operate according to the ink jet print head principle for generating part printed images of the printed image that is to be applied to the outer surface of the container in at least one printing step, and a transport element (7, 16, 54) by means of which the containers (2) are moved in a direction of transport (R, TS) during the printing, wherein the printing groups (10, 10a, 18, 18a, 57) or their print heads (10.1-10.5, 18.1-18.6, 19, 19, 57.1-57.5) are moved, at least during part of the at least one printing step, by means of the transport element (7, 16, 54), characterized in that the print heads (10.1-10.5, 18.1-18.6, 19, 57.1-57.5) are switchable on and switchable off for a print head change or part print change in such a manner that a print head (10.1-10.5, 18.1-18.6, 19, 57.1-57.5) situated in a printing position at the relevant container (2) is movable out of the printing position and another print head (10.1-10.5, 18.1-18.6, 19, 57.1-57.5) is movable into the printing position. 2. Device according to Claim 1, characterized by means (9) for rotating the containers (2) about their container axes during the printing. 3. Device according to Claim 1 or 2, characterized in that for printing part printed images, the print heads (10.1-10.5, 18.1-18.6, 19, 57.1 -57.5) are realized in the form of different colour sets of a multicoloured printed image. 4. Device according to one of the preceding claims, characterized in that the transport element (7, 16, 54) forms a transport section (17) between a container inlet (6) and a container outlet (12), the containers (2) being moved on said transport section during the printing. 5. Device according to one of the preceding claims, characterized in that a plurality of printing stations (8, 55) for one container (2) in each case is provided on the transport element (7, 16, 54). 6. Device according to Claim 5, characterized in that each printing station (8) provided on the transport element (7, 16, 54) has at least one container support (9) for the receiving of one container (2). 7. Device according to one of the preceding claims, characterized in that a device (11, 20) for drying the printing ink applied onto the container surface or the relevant part printed image is associated with each print head (10.1-10.5, 18.1-18.6, 19, 57.1-57.5) or with a group of print heads. 8. Device according to one of the preceding claims, characterized in that an independent printing group (10, 10a) with a plurality of print heads (10.1- 10.5) is associated with each printing station (8) on the transport element (7, 16), and in that the print heads (10.1-10.5) are provided on the transport element so as to be adjustable or switchable further for the part print change. 9. Device according to Claim 8, characterized in that the print heads (10.1- 10.5) are adjustable or switchable on the transport element (7, 16) in the direction of transport (R, TS) and in opposition to the direction of transport (R, TS). 10. Device according to one of the preceding claims, characterized in that the print heads (10.1-10.5) of each printing station (8) are provided on the transport element (7) so as to be pivotable for the part print change, preferably about an axis that is offset relative to the axis of the respective container. 11. Device according to one of the preceding Claims, characterized in that where there is an endlessly rotatingly driveable transport element (7, 16, 54) the printing groups (10, 10a, 18, 18a, 57) are positioned such that at least at the print heads (10.1 - 16.1; 19) located in the print position the discharging of the printing ink is supported by centrifugal forces generated by the movement of the transport element (7, 16, 54). 12. Device according to Claim 11, characterized in that the print heads (10.1 — 10.5, 18.1 - 18.6, 19, 57.1 - 57.5) located in the printing position are positioned with their print nozzles that create the print within the path of movement of the containers (2). 13. Device according to one of the preceding Claims, characterized in that an independent device (11) for drying the printing ink that has been applied onto the outer surface of the container is provided for each printing station (8, 55). 14. Device according to one of the preceding Claims, characterized in that where there is a plurality of container supports (9) provided on the transport element (7, 16) or of printing stations (8) formed by said container supports, at least one printing unit or printing group (18, 18a) common to all the printing stations is provided, past which the containers (2) are moved and which has at least two print heads (19) for generating different part printed images and, in a synchronous manner with the movement of the transport element (7, 16), is entrainable with the transport element in a floating manner in one operating stroke (TR1) out of an initial position and is movable back into the initial position in one return stroke (TR2) in opposition to the direction of transport (R, TS) of the transport element (7, 16) so that in each operating stroke at least one container (2) located at a printing station is printed with the associated part image. 15. Device according to Claim 14, characterized in that the distance between the at least two print heads (21) is identical to the distance between the printing stations (8) or container supports (9) on the transport element (7, 16). 16. Device according to Claim 14 or 15, characterized in that the printing group (18, 18a) for each part printed image has at least one print head unit (18.1-18.6) with at least two print heads (19) for the simultaneous printing of at least two containers (2). 17. Device according to Claim 16, characterized in that the distance between the print heads (19) at the printing group (18, 18a) in the direction of transport (R, TS) of the transport element (7, 16) is identical to the distance between the printing stations (8) or container supports (9) on the transport element (7, 16). 18. Device according to one of Claims 14-17, characterized in that the at least one printing group (18, 18a) is pivotable by a stroke that corresponds to a machine spacing out of the initial position into the end position and out of said end position back into the initial position, and in that the machine spacing is identical to the distance between axes or the angular separation of two adjacent printing stations (8) or container supports (9) on the transport element (7, 16) multiplied by the number of print heads (19) on each print head unit (18.1 - 18.6). 19. Device according to one of Claims 14-18, characterized in that a device (20) for drying or setting the printing ink is provided for each print head (19) of the print head units (18.1 - 18.6). 20. Device according to Claim 19, characterized in that the devices (20) for drying the printing ink are switchable on and switchable off. 21. Device according to one of the preceding claims, characterized in that the at least one floating printing unit or printing group (18) is provided inside and/or outside the rotatably driveable transport element (7, 16). 22. Device according to one of the preceding claims, characterized in that where there is a plurality of container supports (55) provided on the transport element (54) or printing stations formed by said container supports, at least one common printing group or printing unit (57) is provided for all the printing stations, said printing group or printing unit having at least two print head groups, each with at least two print heads (57.1 - 57.5) per print head group for generating different part printed images and, during the printing stage for generating each part printed image, being entrained in the same direction and in a synchronous manner with the movement of the transport element (54), such that in each printing stage at least one print head (57.1 -57.5) of each print head group is situated in a printing position at a container (2), and in that for the print head change, the movement of the printing unit (57) or of the print heads (57.1 -57.5) can be slowed down or accelerated in such a manner and after the print head change can be synchronised again in such a manner with the movement of the transport element (54) that after the print head change a print head (57.1 -57.5) of each print head group is once again situated in a printing position with the respective container (2). 23. Device according to Claim 22, characterized in that the transport element (54) is a rotating transport element, preferably a rotor (54). 24. Device according to Claim 22 or 23, characterized in that the print heads (57.1 - 57.5) of the printing unit (57) are moveable in a circulating manner on a movement path that is closed per se. 25. Device according to one of Claims 22 - 24, characterized in that the print heads (57.1 -57.5) are provided on a rotatably driveable print head support (56). 26. Device according to one of Claims 22 - 25, characterized in that the distance between the print heads (57.1 - 57.5) in the direction of movement of the printing unit (57) or of the print heads (57.1 -57.5) corresponds to the reciprocal distance between the container supports (55) or between the printing stations formed by said container supports in such a manner that during each printing stage, each print head (57.1 -57.5) is situated in the printing position with reference to a printing station or with reference to a container (2) positioned at that location. 27. Device according to one of Claims 22 - 26, characterized in that the number of print heads (57.1 - 57.5) is identical to the number of container supports (55) or of the printing stations formed by said container supports. 28. Device according to one of Claims 22 - 27, characterized in that the number of printing stations (57.1 - 57.5) is an integer multiple of the number of container supports (55) or of the printing stations formed by said container supports on the transport element (54). 29. Device according to one of Claims 22 - 28, characterized in that the number of container supports (55) or of the print stations formed by said container supports on the transport element (54) is an integer multiple of the print heads (57.1 - 57.5) of the printing unit (57). 30. Device for printing, preferably for printing containers (2) in multiple colours by means of a transfer print, said device including at least one printing group (39, 51) with at least two print heads (39.1 -39.5; 51.1 — 51. 5) that operate according to the ink jet print head principle for generating printed images, each consisting of at least two part printed images, onto transfer pads (37, 48) which are moved past the printing group (39, 51), said printed images being transferred onto the containers (2) by rolling off the respective containers (2) at a transfer region, a container conveyor (34, 44) by means of which the containers (2) are moved in a direction of transport (R, TS) during the printing and an auxiliary conveyor (38, 49) with a plurality of transfer pads (37, 48) that are moved with the auxiliary conveyor (38, 39) on a path of movement that is closed per se, characterized in that the container conveyor (34, 44) is a rotor (34) that is rotatably driven about a vertical machine axis (MA) and the auxiliary conveyor is a wheel-shaped or drum-shaped element (38) that is rotatably driveable about the machine axis (MA). 31. Device for printing, preferably for printing containers (2) in multiple colours by means of a transfer print, said device including at least one printing group (39, 51) with at least two print heads (39.1 -39.5; 51.1 - 51. 5) that operate according to the ink jet print head principle for generating printed images, each consisting of at least two part printed images, onto transfer surfaces of transfer pads (37, 48) which are moved past the printing group (39, 51), said printed images being transferred onto the containers (2) by rolling off the containers (2) at a transfer region, a container transport element (34, 44) by means of which the containers (2) are moved in a direction of transport (R, TS) during the printing and an auxiliary conveyor (38, 49) with a plurality of transfer pads (37, 48) that are moved with the auxiliary conveyor (38, 49) on a path of movement that is closed per se, characterized in that the transfer pads (37, 48) are provided so as to be controllable or pivotable on the auxiliary conveyor (38, 49) in such a manner that they are oriented with their transfer surface in a horizontal or substantially horizontal manner when passing the printing group (39, 51) and abut against the outside surface of the upright containers (2) with their transfer surface at the printing position. 32. Device according to Claim 31, characterized in that when passing the printing group (51), the transfer pads (48) are positioned below the printing group or the print heads (51.1 - 51.5). 33. Device according to one of Claims 30 - 32, characterized in that a cleaning station (40, 50) for the transfer pads (37, 48) is provided on the circumferential path of the auxiliary conveyor (38, 49) upstream of the printing group (39, 51). 34. Device according to one of Claims 23 - 25, characterized in that the auxiliary conveyor (49) is a transport element rotating about at least one horizontal axis, for example a transport wheel or a transport element forming at least one vertical or substantially vertical loop. 35. Device according to one of Claims 30 - 34, characterized in that the auxiliary conveyor (38, 49) is driven such that the transfer pads (37, 48) move parallel to the direction of transport (R, TS) of the container conveyor (34, 44) at the transfer region, but at a speed that deviates from the transport speed of the container transport element (34, 44) with regard to direction and/or magnitude. 36. Device according to one of Claims 31 - 35, characterized in that the container transport element is a rotor (7) that is rotatably driveable about a vertical machine axis or a turntable or a transport system (16) with at least one transport element that forms a closed loop. 37. Device according to one of the preceding claims, characterized in that at least one print head (10.5, 19) is used for applying a sealing or protective coating onto the respective printed image. 38. Device according to one of the preceding claims, characterized in that in the direction of transport (R, TS) following the transfer region on the periphery of the container transport element (34, 44) but not being entrained by said container transport element, there is provided at least one device (41, 52) for applying a sealing or protective coating onto the respective printed image and/or a device (42, 53) for drying the respective printed image and/or the sealing and protective coating, in each case with the container (2) rotated about the container axis. 39. Device according to one of the preceding claims, characterized in that a control system (14, 43) for checking the respective container print is provided at the container transport element (7, 16, 34, 44) upstream of the container outlet (12, 35). 40. Device according to one of the preceding claims, characterized by a conveyor (3, 30) that includes a corona tunnel (4, 31) for supplying the containers (2) to the container inlet (6, 33) of the device (1, 1a — 1f). 41. Method for printing, in particular for printing containers in multiple colours on their container outer surface with a print that is formed by at least one printed image, by using at least one printing group (10, 10a, 18, 18a, 57) with at least two print heads (10.1 - 10.5, 18.1 - 18.6, 19, 57.1 - 57.5) that operate according to the ink jet print head principle for generating part printed images of the printed image to be applied to the outer surface of the container in at least one printing step, wherein the containers (2) are moved on a transport element (7, 16, 54) in a direction of transport (R, TS) during the printing and the printing groups (10, 10a, 18, 18a, 57) are entrained with the transport element (7, 16, 54) at least during part of the at least one printing step, characterized in that after printing a part image and before printing another part image a print head change is carried out in such a manner that a print head (10.1 - 10.5, 18.1 - 18.6, 19, 57.1 - 57.5) that is situated in a printing position at the relevant container (2) is moved out of the printing position and another print head (10.1 -10.5, 18.1 -18.6, 19, 57.1 -57.5) is moved into the printing position. 42. Method according to Claim 41, characterized in that during the printing the containers are rotated about their container axes, for example by an angle of 360°. 43. Method according to Claim 41 or 42, characterized in that during the printing steps, part printed images are applied in the form of different colour sets of a multi-coloured printed image and/or in the form of at least one sealing or protective coating covering the printed image. 44. Method according to one of the preceding claims, characterized in that the printing of the containers (2) is effected in each case at a printing station that is provided with a plurality of printing stations (8) of a similar type on the transport element (7, 16), wherein an independent printing group (10, 10a) with a plurality of print heads (10.1 - 10.5) is associated with each printing station (8), and in that for the respective part print change or print head change, the print heads (10.1 - 10.5) are moved relative to the printing station or to its printing position in the direction of transport (R, TS) and in opposition to the direction of transport (R, TS) and/or are pivoted or rotated about an axis, for example about an axis that is offset relative to the axis of the respective container (2). 45. Method according to one of the preceding claims, characterized in that the print heads (10.1 - 10.5, 18.1 - 18.6, 19, 57.1 - 57.5) are each positioned during the printing of the part printed images such that the applying of the printing ink and/or the sealing or protective coating are supported by centrifugal forces that are generated by the movement of the transport element (7). 46. Method according to one of the preceding claims, characterized in that the respective part printed image and/or the sealing or protective coating are dried directly after generation. 47. Method according to one of the preceding claims, characterized in that the printing ink forming the respective part printed image or a compound forming the sealing or protective coating is continuously dried as it is being discharged. 48. Method according to Claim 46 or 47, characterized in that the drying is effected by application of energy, for example by heating and/or by UV light. 49. Method according to one of the preceding claims, characterized in that where there is a plurality of printing positions formed on the transport element (7, 16), the printing of the containers (2) is effected with at least one printing unit (18, 18a) that is common to all printing positions, the containers to be printed being moved past said printing unit, which has at least two print heads (19), and in that the printing unit (18, 18a), for generating in each case a part image with the print heads, is entrained with the transport element (7, 16) out of an initial position in one operating stroke (TR1) and in one return stroke (TR) is moved back into the initial position in opposition to the direction of transport (RTS) of the transport element (7, 16). 50. Method according to Claim 49, characterized in that the printing unit (18, 18a) is moved back into the initial position after each operating stroke (TR1) in such a manner that a container (2) is located at a print head (19) that is situated in the printing position. 51. Method according to Claim 49 or 50, characterized in that at least two containers (2) are printed with different part printed images after each operating stroke (TR1). 52. Method according to one of Claims 50 - 51, characterized in that in each operating stroke, in each case at least two container groups, each comprising at least two containers (2), are printed with different part printed images. 53. Method according to one of Claims 49 - 52, characterized in that in each operating stroke, a first part printed image is applied with at least one print head (19) on at least one container not yet printed with the printing unit or printing group (18, 18a), and another part printed image is applied with at least one second print head on at least one container that is already provided with a part printed image, and in that after each operating stroke (TR1), the printing unit (18, 18a) is moved back into the initial position in such a manner that at the at least one first print head (19) in each case a container (2) not yet printed with the printing unit or printing group (18, 18a) is situated in the printing position and at the at least one other print head (19) a container (2) already printed with the printing unit or printing group (18, 18a) is situated in the printing position. 54. Method according to one of Claims 49 - 53, characterized in that the printing unit or printing group (18, 18a) in each operating stroke (TR1) or return stroke (TR2) is pivoted by a stroke that is identical to the distance between axes or to the angular separation between two printing positions (9) on the transport element (16, 17) or an integer multiple thereof. 55. Method according to one of the preceding claims, characterized in that where there is a plurality of container supports (55) provided on the transport element (54) or of print stations formed by said container supports, at least one printing group or printing unit (57) common to all printing stations is used that has at least two print head groups, each with at least two print heads (57.1 - 57.5) per print head group for generating different part printed images, in that printing unit (57) during each printing stage for generating each part printed image is entrained in the same direction and in a synchronous manner with the movement of the transport element (54) such that in each printing stage at least one print head (57.1 -57.5) of each print head group is situated in a printing position at a container (2), and in that for the print head change, the movement of the printing unit (57) or of the printing heads (57.1 - 57.5) is slowed down or accelerated in such a manner and after the print head change is once again synchronized with the movement of the transport element (54) in such a manner that, after the print head change, a print head (57.1 - 57.5) of each print head group is once again situated in a printing position with the respective container (2). 56. Method according to Claim 55, characterized in that the slowing down or accelerating is effected by temporarily superposing the movement of the printing unit (57) or of the print heads (57.1 - 57.5) that is synchronous with the transport element (54), with another movement component in opposition to or in the direction of transport (R) of the transport element (54). 57. Method according to Claim 55 or 56, characterized in that the print heads (57.1 - 57.5) of the printing unit (57) are moved in a rotating manner on a path of movement that is closed per se. 58. Method for printing, preferably for printing containers (2) in multiple colours by means of a transfer print by using a printing group (39, 51) with at least two print heads (39.1 -39.5; 51.1 - 51. 5) that operate according to the ink jet print head principle, with which print heads the printed images, consisting of at least two part printed images, are applied to transfer pads (37, 48) that are moved past the printing group (39, 51), said printed images then being transferred onto the containers (2) by rolling off the containers (2) at the transfer pads, wherein during the printing the containers (2) are moved on a container transport element (34, 44) and the transfer pads are moved with an auxiliary conveyor (38, 49), characterized in that the containers (2) are moved with the container conveyor (34, 44) and also the transfer pads (37, 48) with the auxiliary conveyor (38, 49) on a circular path about a vertical axis. 59. Method according to Claim 58, characterized in that the transfer pads are moved on a circular path of movement within the circular path of movement of the containers (2). 60. Method for printing, preferably for multiple printing, preferably for multiple printing of containers (2) by means of a transfer print by using at least one printing group (39, 41) with at least two print heads (39.1 -39.5; 51.1 - 51. 5) that operate according to the ink jet print head principle, with which print heads the printed images, consisting of at least two part printed images, are applied to transfer pads (37, 48) that are moved past the printing group (39, 51), said printed images then being transferred onto the containers (2) by rolling off the containers (2) at the transfer pads, characterized in that the printing of the transfer pads (37, 48) is effected in a printing position in which the transfer surface of the respective transfer pad (37, 48) is positioned in a horizontal or substantially horizontal plane, and in that, before the transfer of the respective printed image, the transfer pads (37, 48) are pivoted into a transfer position in which the respective transfer surface abuts against the outside surface of the upright containers (2). 61. Method according to Claim 60, characterized in that during the printing, the containers (2) are moved on a container transport element (34, 44) and the transfer pads are moved with an auxiliary conveyor (38, 49). 62. Method according to Claim 60 or 61, characterized in that, before the transfer of the respective printed image, the transfer pads (37, 48) are pivoted into a horizontal or substantially horizontal transfer position. 63. Method according to one of Claims 60 - 62, characterized in that the printing of the transfer pads (37, 48) is effected with print heads (51.1 - 51.5) positioned above the respective transfer surface. 64. Method according to one of Claims 60 - 63, characterized in that the pivoting of the transfer pads (37, 48) is effected about at least one axis parallel or substantially parallel to the direction of their movement. 65. Method according to one of Claims 58 - 64, characterized in that the transfer pads (37, 48) for the transferring of the printed images are moved parallel to the direction of transport (R, TS) of the containers (2), but at a speed that deviates from the transport speed of the containers (2) with regard to direction and/or magnitude. 66. Method according to one of the preceding Claims 41 - 65, characterized in that the containers (2) are treated in a corona tunnel (4, 31) before the printing. The invention relates to a device and a method for printing containers, especially in multiple colours, on at least one outer surface of the container, using a print formed by at least one printed image, at least one printing group provided with print heads operating according to the ink jet printing principle, for producing partial printed images of the printed image to be applied to the outer surface of the container in at least one printing step, and a transport element for moving the container during the printing in a transport direction. The printing groups are moved with the transport element at least one printing step.

Full Text

Device and method for printing containers
The invention relates to a device in accordance with the preamble of Claim 1, 30
or 31 and to a method in accordance with the preamble of Claim 41, 57 or 59 and
in this case especially to a device or respectively a method for applying a print,
preferably in multiple colours, directly onto the outer surfaces of containers.
Containers in terms of the invention are, in particular, packaging means, in the
form of containers, for the most varied types of liquid products and in this case, in
particular, also bottles or bottle-type containers or cans or can-like containers.
Printing inks in terms of the invention are those colours or inks, in particular, in
lightly viscous liquid form that can be processed with print heads that are digitally
actuatable and operate according to the ink jet print head principle.
Consequently, print heads in terms of the invention are, in particular, print heads
that have a plurality of print nozzles for discharging the printing ink, for example
in at least one row, and that are individually actuatable for discharging the
printing ink and, for this purpose, have a print generating element at the
respective nozzle opening, for example in the form of an electrode of a piezo
element.
Devices for printing containers by using print heads that operate according to the
ink jet print head principle and with relative movement between the print heads
and the respective containers are known. In the case of a known device (WO
2004/009360), during the printing process the containers are each positioned on
a mandrel in the form of a container support. A plurality of print heads are
provided distributed about the mandrel, with which print heads, when the mandrel
is rotated, a coloured printed image, consisting of a plurality of colour sets, is
applied to the respective container. The mandrels are provided on a rotatably
driven transport element, with which, during the printing, the containers are
moved on a transport section formed between a container inlet and a container
outlet.
It is the object of the invention to provide a device with which, at high output, it is
possible to print containers with a high-quality print formed by at least one printed
image. A device according to Claim 1, 30 or 31 is realized to achieve this object.
A method for printing containers is the object of Claim 41, 57 or 59.
In the case of the invention, the containers are printed on their outside surfaces
by applying the printing ink with the print heads directly onto the outer surface of
the container or with a transfer print method by using transfer elements or
transfer pads onto which the respective printed image is applied with the print
heads and is then transferred onto the containers.
Further developments, advantages and application possibilities of the invention
are produced from the following description of exemplary embodiments and from
the Figures. In this case, all described and/all graphically represented features,
individually on their own or in arbitrary combination, are in principle objects of the
invention, independent of their summary in the claims or their dependency. The
content of the claims is also made part of the description.
The invention is described in more detail below by way of the Figures of
examples of devices for printing containers in multiple colours on an outer
surface of the container that is realized in a rotationally-symmetrical manner
about a container axis, for example on an outer surface of a container that is
cone-like or in the shape of a circular cylinder, in which, in detail:
Figures 1 and 2 show a schematic, perspective representation and a top view of
the device according to the invention;
Figure 3 shows a partial representation of a top view of a rotor of the device
in Figures 1 and 2, said rotor being rotatably driveable about a vertical machine
axis;
Figures 4-6 show representations as in Figures 1 - 3 of an additional specific
embodiment of the invention;
Figures 7 and 8 show a schematic, perspective representation and top view
of another specific embodiment of the device according to the invention;
Figure 9 shows a top view of a part representation of the transport system of
the device in Figures 7 and 8 with the printing groups;
Figures 10 and 11 show a schematic, perspective representation and top view of
another specific embodiment of the device according to the invention;
Figure 12 shows a part representation and top view of the rotor, in different
positions, together with a printing unit that includes a plurality of print head
elements in different operating states, said rotor being rotatably driveable about
the vertical machine axis;
Figure 13 and 14 show a schematic, perspective representation and top view of
another specific embodiment of the device according to the invention;
Figure 15 shows a part representation of the conveyor in Figures 13 and 14,
in different positions, together with a printing unit that includes a plurality of print
head elements in various operating states;
Figures 16 and 17 show a schematic, perspective representation and top view of
another specific embodiment of the device according to the invention;
Figures 18 and 19 show a schematic, perspective representation and top view of
another specific embodiment of the device according to the invention;
Figures 20 and 21 show a schematic, perspective representation and top view of
another specific embodiment of the device according to the invention;
Figure 22 shows, shows a schematic representation and part representation in
each case, of different operating states of the device in Figures 20 and 21, in
various positions.
In Figures 1 - 3 the reference 1 is given to a device for printing containers 2 in
multiple colours on their outer or outside surface and, in this case, preferably on
a region of the container outside surface that is realized in a rotationally-
symmetrical manner with reference to the container axis, for example on a
circular cylindrically shaped or frustum-shaped or substantially circular
cylindrically shaped or frustum-shaped region of the outer surface of the
container.
The containers 2 are supplied to the device 1 by means of a conveyor, identified
schematically in the Figures by the reference 3, standing upright, i.e. oriented
with their container axes in the vertical direction and in a single-track container
flow in the direction of transport specified by the arrow T and after they pass a
corona tunnel 4 and a separating screw 5 they reach a rotor 7 of the device 1. At
the periphery of the rotor 7, which is rotatably driveable about a vertical machine
axis MA in the direction of the arrow R, printing stations 8 are formed at regular
angular spacings offset about said machine axis, said printing stations
comprising in each case substantially a container support 9, in the form of a
turntable that is rotatable in a controlled manner about an axis parallel to the
machine axis, a printing group 10 and a device 11 for drying and/or setting the
printing ink. Each printing group 10, in the specific embodiment represented,
includes four print heads. 10.1 - 10.4 for generating various colour sets of a
multiple colour print or printed image and another print head 10.5 for flat printing
or applying a transparent sealing or protective coating, for example a covering
finish onto the printed image generated with the print heads 10.1 - 10.4.
The print heads 10.1 - 10.4 are digitally actuatable print heads of the ink jet print
head type, for example print heads that can be obtained commercially under the
reference "XAAR" or "Xaar500". The print heads 10.1 - 10.5 each comprise,
correspondingly, a housing with a plurality of individually actuatable print nozzles
for discharging the printing ink in the distribution and quantity corresponding to
the respective printed image or colour set on the background to be printed on ,
i.e. in the present case onto the outer surface of the container to be printed on.
The print nozzles, oriented with their axes horizontally or substantially
horizontally, are positioned on each print head 10.2 -10.5 in at least one row
parallel or substantially parallel to the vertical machine axis MA. The discharging
of the printing ink is achieved, for example, through corresponding actuation of
electrodes or of piezo elements in the print heads 10.1 -10.5, for example at an
actuating frequency of up to 50 kHz and a relative movement between the
respective print head and the surface to be printed of 560 mm/second. The
number of print nozzles per print head is, for example, in the range of 500 with a
print width of approximately 70 mm. The print heads 10.1 - 10.4 include colour
printing ink in different colours, namely in yellow, magenta, cyan and black.
As shown in Figures 1 - 3, the print heads 10.1 - 10.5 of all the printing stations
8 are positioned on a common circular line surrounding the machine axis MA in
such a manner that the print heads of all the printing groups 10 entrained with the
rotating rotor 7 are situated, with reference to the machine axis MA, inside a
circular path on which the container supports 9 move. The print nozzles of all the
print heads 10.1 - 10.5, consequently, with reference to the machine axis MA,
are aligned with their axes constantly radially outwards such that the discharging
of the printing ink onto the containers 2 is supported by the centrifugal force
when the rotor 7 is rotating.
The printing group 10 of each printing station 8, as detailed, is realized in a
rotating manner with the rotor 7, however, for the print head change, is at the
same time pivotable about the machine axis MA in a successive manner or is
switchable further in the direction of rotation of the rotor and in opposition to said
direction of rotation such that when a container 2 is being printed, each print
head 10.1 -10.5 can be moved at least once into a printing position in which the
relevant print head with its print nozzles is directly adjacent the container 2
standing upright on the container support 9 with a small distance in between (e.g.
less than 1 mm). The device 11, which performs the drying of the printing ink
through an application of energy or heat and/or UV radiation, is provided about
the axis of the respective container support 9 offset by approximately 90° relative
to the printing group 10. With the device 1, the devices 11 are positioned on a
common circular line surrounding the machine axis MA, the radius of said circular
line being identical or substantially identical to the distance between the axes of
the container supports 9 and said machine axis MA, in such a manner that in the
direction of rotation R of the rotor the respective device 11 is ahead of the
associated container support 9.
For the printing, the containers 2 are transferred in each case individually via the
transport star 6 to a printing station 8, at which, with a controlled rotational
movement of the container support 9 and consequently with a controlled
rotational movement of the containers 2 about their container axes, one after the
other the colour sets forming the colour print are printed with the print heads 10.1
- 10.4 and then the protective coating is applied with the print head 10.5.
In detail, the printing of each container is effected such that, after the transfer to a
printing station 8, the colour set corresponding to the print head or the final
protective coating are printed onto the outer surface of the container with the
print heads 10.1 - 10.5 each switched into the printing position, and during the
printing of each colour set and possibly also even during the switching further of
the printing group 10 by a print head spacing or by a print head, the drying of the
applied printing ink is performed by means of the device 11. During each printing
step, i.e. during the printing of the respective colour set or the applying of the
protective coating and the drying of the printing ink or of the protective coating,
each container 2 is rotated by 360°. Each printing step with the drying is effected
for example on an angular region of the rotational movement of the rotor 7 of ca.
50° such that the printing of the containers 2 is completed reliably before the
containers 2 reach a container outlet at which they are discharged via a transport
star 12 on a conveyor 13. The resetting of the printing groups 10 into the initial
position is effected in the angular region of the rotational movement of the rotor 7
between the transport stars 12 and 6. An improved or sharper printed image is
achieved through the treatment in the corona tunnel by charging the containers 2
electrostatically on their outer surface.
An optoelectric control system 14 is provided in the direction of rotation R of the
rotor directly before the transport star 12, by means of which control system the
print on the containers 2, which are moved past said system and are rotated
further about the container axis, is checked so that containers with a faulty print
can be discharged on the conveyor 13.
Figures 4-6 show, in the form of another specific embodiment, a device 1a
which only differs substantially from the device 1 in that at the individual printing
stations 8 instead of the printing groups 10, printing groups 10a are provided that
have the print heads 10.1 - 10.5 at a support 15, which can be switched further
for the print head change by rotating about an axis parallel to the machine axis
MA. The print heads 10.1 - 10.5 are provided distributed at regular angular
distances on the periphery of the support 15. The supports 15 are situated, in
their turn, inside the path of movement of the container supports 9 such that each
print head moved into the printing position, i.e. positioned directly adjacent the
container 2 to be printed,- is aligned with its print nozzles radially outwards with
reference to the machine axis MA. The printing of the containers 2 is effected, in
the case of the device 1 a, once again onto the angular region of the rotational
movement of the rotor 7 between the transport star 6 and the control system 14,
the corresponding print head being switched into the printing position for each
colour set and for the sealing or protective coating. The printing ink or the
sealing or protective coating is dried by means of the device 11 during the
printing. The respective container 2 is rotated by 360° during the printing steps
(applying the colour sets, the sealing or protective coating and the drying).
Figures 7 and 8 show, in the form of another embodiment, a device 1b which
only differs substantially from the device 1 in that instead of the rotor 7, there is
provided a transport system 16, which on at least one transport element, which
forms a closed loop and is driveable in an endlessly circulating manner, has a
plurality of printing stations 8 at regular spacings, each with a container support
9, a printing group 10 and a device for drying the printing ink.
The containers 2 are supplied to the device 1a once again via the transport star 3
with the corona tunnel 4 and are transferred in each case individually via the
transport start 6 to a printing station 8, with which the respective container 2 is
then moved during the printing in the direction of transport TS on the transport
section 17 of the transport system 16. The printed containers 2 are forwarded to
the conveyor 13 with the transport star 12 that forms a container outlet.
The printing of the containers 2 with the individual printing inks or colour sets of
the multi-coloured print and the applying of the sealing or protective coating is
effected analogously to the description given in conjunction with the device 1.
For this purpose, the printing groups 10, entrained with the transport system 16
or their print heads 10.1 - 10.5 are moveable or switchable for the print head
change relative to the transport system 16 in the direction of transport TS and in
opposition to said direction of transport and are situated on the inside of the loop
formed by the transport system 16. The devices 11 of all the printing stations 8
are positioned on a common loop line which also intersects the vertical axes of
rotation of the container supports 9, the container supports 9 being ahead of the
associated device 11 in each case in the direction of transport TS.
In detail, the printing of the containers 2 is effected once again in such a manner
that by switching further the print heads 10.1 - 10.5, the respective colour set or
the sealing or protective coating are applied, and during the printing process,
possibly also still during the switching further of the print heads, the drying of the
printing ink and the sealing or protective coating is effected by means of the
associated device 11, the respective container with the container support 9 being
rotated by 360°.
Figures 10-12 also show, in the form of another embodiment of the invention, a
device 1c for printing containers 2 in multiple colours. The device 1c differs from
the device 1 in that a plurality of container supports 9 is provided on the
periphery of the rotor 7 at regular angular spacings about the vertical machine
axis MA, however, said container supports 9 are not components of the printing
stations each with independent printing groups.
In the case of the device 1c, one single printing group or unit 18 is in fact
provided with a plurality of print head units 18.1 - 18.5, each unit of which having
a plurality of print heads 19, in the specific embodiment represented two print
heads in each case. The print heads 19 are realized in the same manner as the
print heads 10.1 - 10.5. Each print head unit 18.1 - 18.5 or its print heads 19
serve in the manner described in more detail below for simultaneously
discharging the colour sets of a colour associated with the respective print head
unit or the sealing or protective coating onto a number of containers 2
corresponding to the number of print heads 19, i.e. in the case of the specific
embodiment represented for simultaneously discharging onto two containers 2.
The print head units 18.1 - 18.5 are also each realized with two devices 20 that
can be switched on or off for drying the respective print or the printing ink, for
example by the application of energy, e.g. by heating and/or UV light, in each
case one device 20 being associated with one print head 19. The print head
units 18.1 - 18.5 with their print heads 19 and their devices 20 are positioned on
a common support 21, which can be moved or pivoted back and forth about the
machine axis MA by a stroke that corresponds to a machine spacing, as is
indicated in particular in Figure 12 with the arrows TR1 and TR2. The print unit
18 formed by the print head units 18.1 - 18.5 and the support 21 is therefore
floating. It is situated, with reference to the machine axis MA, inside the path of
movement on which the container supports 9 move when the rotor 7 rotates. In
addition, the individual print heads 19 are positioned such that they point radially
outwards with their print nozzles, each positioned in a row parallel or
substantially parallel to the machine axis MA, with reference to said machine
axis, such that the discharging of the printing ink is once again supported by the
centrifugal force when the rotor 7 is rotating.
The arrangement is also such that the spacing between the print heads 19 on
each print head unit 18.1 - 18.5, but also the spacing between adjacent print
heads 19 on print head units 18.1 -18.5 following one another in the
circumferential direction of the rotor 7 is identical to the angular spacing between
two adjacent container supports 9. In addition, the devices 20 in the activated or
switched-on state, seen in a top view of the rotor 7, are offset by 90° relative to
the print heads and are positioned on a circular line that surrounds the machine
axis MA and also intersects the axes of rotation of the container supports in the
direction of rotation R of the rotor ahead of the adjacent container support or the
container 2 standing upright on said container support in each case. Each print
head unit 18.1 - 18.4 has associated therewith in each case a colour set or a
colour, namely yellow, magenta, cyan or black. The print head unit 18.5 or its
print heads 19 serve for discharging or printing the sealing or protective coating.
The print head units 18.1 - 18.5 are provided following one another in the
direction of rotation R of the rotor in order of their reference numbers, i.e. in the
direction of rotation R of the rotor the print head unit 18.1 forms the first print
head unit of the printing unit 18 and the print head unit 18.5 forms the last print
head unit of the printing unit 18.
The multi-coloured printing of each container 2 is effected once again in several
chronological printing steps in which the printing, i.e. discharging the relevant
colour set or the sealing or protective coating and the drying is effected with the
containers 2 rotating about the container axes, for example rotating about 360°.
The individual printing steps are executed at each container chronologically one
after the other by the print head units 18.1 - 18.5, with each print head unit 18.1
- 18.5 at two containers simultaneously in each case. During each printing step,
the printing unit 18 is entrained in the same direction and in a synchronous
manner with the rotor 7 (arrow TR1). The devices 20, in this case, are delivered
and activated so that the drying of the generated colour sets is also effected
during each printing step.
After the completion of each printing step and before the introduction of a new
printing step, the printing unit 18 is pivoted back, with devices 20 retracted, in
opposition to the direction of rotation R of the rotor by the machine spacing into
the initial position (arrowTR2), in which then, on account of the rotational
movement of the rotor 7, an unprinted container 2 in each case is adjacent the
print heads 19 of the print head unit 18.1 and a container 2 in each case that has
already been printed in a previous printing step by the print heads 18.1 - 18.4 is
adjacent the print heads 19 of the print head units 18.2-18.5 for another printing
step. In the next printing step, the floating printing unit 18 is then entrained again
in the same direction and in a synchronous manner with the rotational movement
of the rotor 7 by the machine spacing (arrow TR1) and after completion of this
printing step is pivoted back by the machine spacing into the original position
(arrow TR2). The machine spacing, in this case, is twice the spacing between
two container supports 9.
The printing of the containers 2 in multiple colours is completed before said
containers 2 reach the transport star 12 that forms the container outlet, so that,
also in the case of the device 1c, a control system 14, for example an
optoelectric control system is provided in the direction of rotation R of the rotor
before the transport star 12 for checking the respective print on the containers 2
moved past said system and being rotated at the same time so that containers 2
with missing or faulty print can subsequently be discharged onto the conveyor
13.
Figures 13-15 show, in the form of another embodiment, a device 1 d which
differs in the first instance from the device 1c in that instead of the rotor 7 a
transport system 16 is provided that forms a closed loop and is driven in an
endlessly circulating manner. The container supports 9 are provided on said
transport system 16. In addition, at the transport section 17 of the transport
system 16 on which the printing of the containers 2 in multiple colours is effected,
there is provided a printing unit 18a, which comprises a plurality of print head
units, namely a total of six print head units 18.1 - 18.6, three of which print head
units 18.1 - 18.3 or 18.4 - 18.6 are positioned in each case on each side of the
transport section 17. The transport system 16 has the container supports 9 at
regular spacings.
The print head units 18.1 - 18.6 are realized in the identical manner as described
for the device 1c for the print head units 18.1 -18.5 used there, i.e. each print
head unit 18.1 - 18.6 has two print heads 19 spaced apart by half the machine
spacing and two devices 20 also spaced apart by half the machine spacing. In
addition, the print heads 19 and devices 20 of print head units 18.1 - 18.3 or 18.4
- 18.6 adjacent one side of the transport section 17 are each spaced apart by
half the machine spacing.
The printing unit 18a or the print head units 18.1 - 18.6 positioned on a support
(not shown) are moveable by a drive (not shown) in a synchronous manner and
in the same direction with the movement of the transport system 16 out of an
initial position in the direction of transport TS by the machine spacing and in
opposition to the direction of transport TS back into the initial position, said
floating movement also being synchronized with the movement of the transport
system 16 in such a manner that after the movement back into the initial position,
each print head 19 with its printing nozzles is once again situated directly
opposite a container support 9 or a container 2 at that location.
The containers 2 to be printed are supplied to the device 1d by means of the
conveyor 3 with the corona tunnel 4 and are transferred in each case individually
to a container support 9 by means of the transport star 6. Once the containers 2
have been printed on the transport section 17, the printed containers are
removed from the container supports 9 by means of the transport star 12 and are
forwarded to the conveyor 13.
The printing of the containers 2 is once again executed in several chronological
printing steps, in each printing step a number of containers 2 that corresponds to
the number of print heads 19 of the print head units 18.1 - 18.6, i.e. in the case
of the device 1d in each case two containers 2 being printed simultaneously with
the two different colours associated with the print head units (at the print head
units 18.1/18.4, 18.2/18.5) or with the finish that forms the sealing or protective
coating and a printing ink (at the print head units 18.3/18.6). During each printing
step the print heads 19 of the print head units 18.1 - 18.6 are adjacent a
container 2. The printing is carried out by rotating the containers 2, for example,
by 360° with the devices 20 activated such that the printing ink applied with one
print head 19 is dried by the device 20 following said print head in the direction of
rotation of the respective container 2 before a printing ink or finish is applied once
again in the same printing step by the other print head 19. During each printing
step the printing unit 18a is entrained in the same direction and in a synchronous
manner with the transport unit. At the end of the printing step the printing unit
18a is moved back into the initial position so that in another printing step a print
application can then be effected with the print head units 18.1 and 18.4 onto still
unprinted containers 2 in each case and a print application can be effected with
the print head units 18.2, 18.3 and 18.5, 18.6 onto such containers 2 that have
already been printed in a previous printing step with the print head units 18.1,
18.4 or 18.2, 18.5.
Whereas, in the case of the abovementioned devices 1 - 1 d, the printing of the
containers 2 in multiple colours on their container outer surface is effected
directly with the printing groups or their print heads, Figures 16 and 17 show a
device 1e for printing containers 2 in multiple colours in a transfer print. The
printing in multiple colours is once again effected on the container outer surface
or container outside surface and in this case preferably, with regard to the
container axis, on a rotationally symmetrically realized region of the container
outer surface, for example on a circular cylindrical-shaped or frustum-shaped
region of the container outer surface.
By means of a conveyor, which is schematically represented in Figures 16 and
17 and identified with the reference 30, the containers 2 are supplied to the
device 1e in the direction of transport specified by the arrow T, standing upright
and in a single-track container flow, and having passed a corona tunnel 31
provided on the conveyor 30 and a separating screw 32 they reach a rotor or
turntable 34 of the device 1e by means of a transport star 33. At the rotor 34 the
containers 2 are retained so as to be rotatable about their container axes at
container supports provided at that location (not shown) and are moved during
the printing with the rotor 34 on a circular transport section. The printed
containers are removed from the rotor 34 by a transport star 35 and are
forwarded to a conveyor 36.
The printing of the containers 2 in multiple colours is effected by using transfer
pads 37, which are provided on the periphery of a transfer drum 38, which is
rotatably driveable about the machine axis MA in the direction of rotation R of the
rotor but at a speed that is increased compared to the rotational speed of the
rotor 34. The transfer pads 37 are provided at the transfer drum 38 so as to be
adjustable radially relative to the machine axis MA between a switched-on
position located radially further outside and a switched-back position located
radially further inside. In addition, the transfer pads 37 are positioned such that
they move with their outer face, curved in an arcuate manner about the machine
axis MA, inside the circular path of movement of the containers 2 or of the
container supports between the transport stars 33 and 35.
A printing group 39 is provided in the direction of rotation R of the rotor 34 or of
the transfer drum 38 upstream of the transport star 33, with which printing group
the printed image to be discharged onto the container 2 is applied to the outer
face of the transfer pad 37. The printing group 39 comprises a plurality of print
heads 39.1 - 39.4 following one another in the direction of rotation R of the rotor
for different colours, for example for yellow, magenta, cyan and black or for
generating the various colour sets.
The print heads 31.1 - 31.4 are digitally controllable print heads of the ink jet
print head type, for example print heads that are commercially available under
the name "XAAR" or "Xaar500". The print heads 31.1 - 31.4 each comprise
accordingly a housing with a plurality of individually actuatable print nozzles or
nozzle openings for discharging printing ink in the distribution and quantity
corresponding to the respective printed image or colour print onto the
background to be printed, i.e. in the present case onto the outside surface to be
printed of each transfer pad moved past the printing group 39. The printing
nozzles positioned with their axes horizontally or substantially horizontally are
positioned at each print head 39.1 - 39.4 in at least one row parallel or
substantially parallel to the vertical machine axis MA. The discharging of the
printing ink is achieved through corresponding actuation of electrodes or of piezo
elements or actuators in the print heads, for example at an actuating frequency
up to 50 kHz and a relative movement between the respective print head and the
surface of a transfer pad to be printed of ca. 560 mm/second. The number of
print nozzles per print head, for example, is in the range of 500 with a print width
of 70 mm. The print heads 39.1 - 39.4 include printing inks each in different
colours, namely yellow, magenta, cyan and black.
In the direction of rotation R of the rotor upstream of the printing group 39 there is
a cleaning station 40, for example in the form of a cleaning roller, by means of
which any printing ink or ink residue is removed from the print or transfer pad 37
before a new printed image is applied.
At the region of the rotor 34 utilized for printing the containers 2, said region in
the specific embodiment represented corresponding to an angular region of
approximately 180°, following the inlet star 33 there is provided a device 41 for
applying a finish forming a sealing or protective coating on the respective
container print, connecting thereto in the direction of rotation R of the rotor a
device 42 for drying the container print, including the sealing and protective
coating, for example by application of energy, for example heating or UV light
and connecting thereto directly in front of the outlet star 35 an optoelectric control
system 43, by means of which the printed containers are checked with regard to
the quality of the print whilst rotating about their vertical axes so that wrongly
printed containers 2 can then be discharged on the conveyor 36.
In detail, the printing of the containers 2 is effected with the device 1e in such a
manner that the containers 2 transferred individually in each case with the inlet
star 33 to the rotor 34 or to the container supports at that location are rolled over
by the switched-on transfer pads, provided with the printed images on the outer
surface, by reason of the transfer drum 38 that rotates somewhat faster
compared to the rotor 34, the containers therefore roll off the transfer pads by
rotating about their vertical container axes and consequently the printed image is
transferred from the respective transfer pad onto a container 2. As the
respective transfer pad 37 is still rolling off, that is still inside the transfer region,
the containers 2 are moved past the device 41, by means of which the finish that
forms the sealing or protective coating is applied to the respective container,
rotating about the container axis in a continuous manner, onto the part of the
container print already generated by rolling off the transfer pad 37 on the outer
surface of the container.
The devices 41 and 42 and the control system 43 are situated with the rotor 34 in
a non-entraining manner on the periphery of the path of movement of the
containers 2.
After the completed transfer of the printed image from the transfer pad 37 onto
the outer surface of the relevant container 2 or after the completed rolling off of
said container on the relevant transfer pad 37 and after the completed applying
of the sealing or protective coating, the relevant transfer pad 37 is switched back
and the respective container 2, continuing to be rotated about its container axis,
is moved past the device 42 for drying the print and past the control system 43
and finally is discharged with the transport star 35 onto the conveyor 36.
After passing the transport star 35, the transfer pads 37 are switched-on once
again, i.e. moved radially outwards for the cleaning process at the cleaning
station 40 and for the application of a new printed image at the printing group 39.
The treatment of the containers 2 in the corona tunnel 31 and the electrostatic
charging of the containers 2 at that location produce a substantial improvement
in the multi-colour print that is generated with the transfer print onto the outer
surfaces of the containers.
In a very schematic representation, Figures 18 and 19 show a device 1 f that is
once again realized for a transfer print in multiple colours on the outer surfaces of
containers 2. In the case of this device, the printing of the containers 2 is
effected on a transport system 44 that forms a closed loop and is driven in an
endlessly circulating manner or respectively on a substantially linear transport
section 45 of said system. Container supports 46 are provided at regular
spacings on the transport system 44. The containers 2 to be printed are supplied
to the transport section 45 via the conveyor 30 with the corona tunnel 31 and are
transferred individually in each case via the transport star 33 to a container
support 46, with which the relevant container 2, retained so as to be rotatable
about its container axis, is moved during the printing in the direction of transport
TS to the transport star 35, by means of which the printed containers 2 are
removed from the transport system 44 and forwarded to the conveyor 36.
For printing the containers 2 in multiple colours, there is a print device 47
provided at the transport section 45 that includes a plurality of transfer elements
or transfer pads 48, which are provided at an auxiliary conveyor 49 so as to be
rotating with said auxiliary conveyor, said auxiliary conveyor forming a closed
loop. The auxiliary conveyor 49 having the transfer pads 48 forms a vertical loop
that is provided with its upper horizontally extending loop length 49.1 parallel to
the transport section 45 and directly adjacent to said transport section on one
side. In their initial position, the transfer pads 48, which, for example, are
substantially rectangular and with their longitudinal extension are oriented in the
circumferential direction or in the direction of movement of the auxiliary conveyor
49, are positioned with their surface sides in planes perpendicular to the loop
plane of the auxiliary conveyor 49.
The auxiliary conveyor 49 is driven in such a manner that its upper length 49.1
moves in the direction of transport TS of the transport section 45, however at a
greater speed than the transport section 45.
At the upper length 49.1, following one another in the direction of transport TS
there is provided a cleaning station 50 in the form of a cleaning roller for
removing printing ink residue on the transfer pads 48 and then a printing group
51. The printing group 51 comprises a plurality of print heads 51.1 - 51.5
following one another in the direction of transport TS, said print heads being
realized, for example, in an identical manner to the print heads 39.1 - 39.5,
however being positioned in such a manner that the print nozzles of said print
heads are oriented with their axes in the vertical direction and the rows on each
print head formed by the print nozzles are oriented in the horizontal direction
perpendicularly or at right angles to the direction of transport TS. The printing
group 51, positioned above the path of movement of the transfer pad 48,
executes the printing of each transfer pad 46 moved past on the top side
positioned in a horizontal plane. After the printing each transfer pad 48 is set up
such that with its side that has the printed image, it is positioned in a vertical
plane parallel to the direction of transport TS such that the respective container 2
to be printed, being rotated about its container axis, rolls off a transfer pad 48
and in so doing the printed image is transferred from the transfer pad 48 to the
outer surface of the container. At the same time a device 52 applies the sealing
or protective coating and a device 53 dries the print.
The device 1f also offers, among other things, the advantage of it being possible
to position the print heads of the print group 51 that operate according to the ink
jet print head principle in a position that is optimum for the method of operation,
namely with their print nozzles above the path of movement of the transfer pads
48 and with the axes of the print nozzles oriented downwards in the vertical
direction.
Once the printed image has been transferred, the relevant transfer pad 48 is
pivoted back again into its initial position.
In a very schematic manner, Figures 20 - 22 show a device 1g that is realized
similar to the devices 1, 1a - 1d for printing containers 2 in multiple colours on
their outer surfaces by applying the printing ink
directly onto the outer surface of the container. In the case of this device, the
printing is executed on a transport element in the form of a rotor 54, which is
rotatably driven about the vertical machine axis (arrow R) and on which are
provided container supports 55, offset from one another at regular angular
spacings about the vertical machine axis, for the containers 2 standing upright,
i.e. with their container axes oriented in the vertical direction. A ring-shaped print
head support 56, which is positioned in an axially identical manner to the
machine axis, is provided inside the path of movement of the container supports
55, on said print head support in the same spacing or at the same angular
spacing that is between the container supports 55, print heads 57.1 - 57.4 are
provided for printing inks in the various colours, namely in yellow (print head
57.1), in magenta (print head 57.2), in cyan (print head 57.3) and black (print
head 57.4) along with other print heads 57.5 for applying the coating or protective
finish. The print heads 57.1 - 57.5 are each provided in groups on the print
head support 56 in such a manner that each group has the print heads 57.1 -
57.5 once and the print heads 57.1 - 57.5 in each group have the same
sequence, i.e. for example are provided following one another in the order of
their reference numbers in the circumferential direction of the print head support
56, for example in opposition to the direction of rotation R of the rotor 54. The
arrangement of the print heads 57.1 - 57.5 is additionally such that in each
printing stage (e.g. positions a and c in Figure 22) one print head 57.1 - 57.5 is
always situated directly opposite a container 2 or its outside surface in the
printing position. In this specific embodiment, the print heads 57.1 - 57.5
together with the print head support 56 form the printing group 57.
For printing, the containers 2 are once again supplied to the inlet or transport star
6 via the corona tunnel 4 and the separating screw 5 (arrow T) and are
transferred in each case individually from said inlet or transport star to a printing
station formed by a container support 55. The printed containers 2 are removed
at the outlet or transport star 12 and supplied via the conveyor 13 to another use
(arrow T).
The container 2 is printed in multiple colours during the transport with the rotor 54
between the inlet star 6 and the outlet star 12. The colour sets forming the
respective multi-colour print and the connecting protective coating are applied in
each case one after the other with the print heads 57.1 - 57.4 or with the print
head 57.5 with the containers 2 being rotated or pivoted in a controlled manner
about the container axes with the container supports 55, for example with a
controlled rotational movement in each case about 360°.
In detail, the printing of each container 2 is executed such that, after being
transferred from the inlet star 6 the container 2 is situated opposite a container
support 55 in a first angular region of the rotational movement of the rotor 54, i.e.
in a first printing stage it is situated opposite a print head for generating a first
colour set, for example the print head 57.1 (Figure 22, position a). During this
printing stage the print head support 56 is entrained in the same direction and in
a synchronous manner with the rotor 54. When the colour set is applied, the
container 2 is rotated in a controlled manner about its vertical container axis by
360° and at the same time the printing ink applied in each case is dried by means
of a suitable device 58 that is associated with each print head 57.1 - 57.5.
The printing stage for applying another colour set or for applying the protective
coating that follows the first or in each case another printing stage is introduced
by the container support 55 or all the print heads 57.1 - 57.5 being stopped for a
short time or being moved by a spacing in opposition to the rotational movement
so that the containers "overtake" the print heads 57.1 - 57.5 by a spacing
(distance between the print heads) (Figure 22, position b) and thus another print
head is situated opposite each container 2 in a printing position, for example,
after the print head 57.1 the print head 57.2, after the print head 57.2 the print
head 57.3, after the print head 57.3 the print head 57.4 or after the print head
57.4 the print head 57.5. It is obvious that in each printing stage following a
previous printing stage that is effected once again on an angular region of the
rotational movement of the rotor 54, the print head support 56 or the print heads
57.2 - 57.5 are also entrained with the rotor 54 in a synchronous manner at the
identical speed and in the same direction.
With rotor 54 the printed containers 2 are moved past a hardening or curing
station 59 for complete hardening of the printing ink and of the protective coating
and then, connected thereto, before reaching the outlet star 12, are moved past a
control station or a control system 14, by means of which the print on the
container moved past said system and also rotated about its vertical container
axis is checked so that any containers with a faulty print can be discharged on
the conveyor 13.
In the case of the device 1 g, the number of container supports 55 on the rotor 54
is an integer multiple of the number of print heads 57.1 - 57. 5 in each print head
group. Accordingly, the angular spacing or spacing between container support
55 in the case of the device 1g is equal to 3607(n1 x n2), wherein
n1 = number of print heads 57.1 - 57. 5 per print head group, namely for
example five
n2 = number of print head groups on the print head support 56.
It has been assumed above that the print head change between two printing
stages following one after the other is effected by slowing down the print head
support 56 briefly so that the print heads 57.1 - 57.5 are "overtaken" by the
containers 2. In principle, a print head change is also obviously possible in the
reverse manner by briefly accelerating the print head support 56 in each case so
that the container supports 55 or the containers 2 are "overtaken" by the print
heads 57.1 - 57.5 during the print head change. In each case, however, the
print head support 56 in the printing stage after the print head change and before
a new print head change is driven in the same direction and in a synchronous
manner with the rotor 54.
For reasons of simplicity, the print head support 56 is represented as a ring in
Figures 20 - 22. In the embodiment of the device 1g in practice, it is possible for
said support to have any arbitrary embodiment that can be used for the function.
Thus it is possible, in particular, to realize the print head support 56, for example,
in two parts at least, comprising at least one first element that is entrained with
the rotor 54 and at least one other guided element, which is provided at said first
element and is switchable further for the respective print head change relative to
the first element about the vertical machine axis through stepwise rotation by a
spacing (distance between the print heads 57.1 - 57.5), for example in
opposition to the direction of rotation R of the rotor 54 or in said direction of
rotation.
The device 1g has, among other things, the advantage that at least the larger
part of the angle of the rotational movement of the rotor 54 is available for the
printing process, the number of print heads 57.1 - 57.5 can nevertheless be kept
relatively small such that the total number of print heads 57.1 - 57.5, for
example, is equal to the number of container supports 55, and the respective
print head change can be effected through short movement strokes.
In the case of the device 1g also, the print heads 57.1 - 57.2 are positioned once
again inside the path of movement of the containers 2 on the rotor 54 so that the
applying of the printed images or of their colour sets is supported by the
centrifugal force of the rotating rotor 54 and print head support 56.
The invention has been described above by way of exemplary embodiments. It
is obvious that numerous changes and variations are possible without departing
from the inventive concept underlying the invention.
Thus it has been assumed above that during the printing the containers 2 stand
with their container bottom on a container support or on a surface of a rotor or of
a transport system. Obviously embodiments are also possible where the
containers 2 are retained in another manner during the printing, for example
suspended at a container or neck flange provided in the region of the container
mouth.
It has also been assumed above that the drying of the respective colour set is
effected during the printing. In principle, however, it is also possible for the
drying not to be effected until the respective colour set has been applied to the
outer surface of the container.
WE CLAIM
1. Device for printing, in particular for printing containers (2) in multiple
colours on at least one outer surface of the container, said device
including a print that is formed by at least one printed image, at least one
printing group (10, 10a, 18, 18a, 57) with at least two print heads (10.1-
10.5, 18.1-18.6, 19, 19, 57.1-57.5) that operate according to the ink jet
print head principle for generating part printed images of the printed image
that is to be applied to the outer surface of the container in at least one
printing step, and a transport element (7, 16, 54) by means of which the
containers (2) are moved in a direction of transport (R, TS) during the
printing, wherein the printing groups (10, 10a, 18, 18a, 57) or their print
heads (10.1-10.5, 18.1-18.6, 19, 19, 57.1-57.5) are moved, at least during
part of the at least one printing step, by means of the transport element (7,
16, 54), characterized in that the print heads (10.1-10.5, 18.1-18.6, 19,
57.1-57.5) are switchable on and switchable off for a print head change or
part print change in such a manner that a print head (10.1-10.5, 18.1-18.6,
19, 57.1-57.5) situated in a printing position at the relevant container (2) is
movable out of the printing position and another print head (10.1-10.5,
18.1-18.6, 19, 57.1-57.5) is movable into the printing position.
2. Device according to Claim 1, characterized by means (9) for rotating the
containers (2) about their container axes during the printing.
3. Device according to Claim 1 or 2, characterized in that for printing part
printed images, the print heads (10.1-10.5, 18.1-18.6, 19, 57.1 -57.5) are
realized in the form of different colour sets of a multicoloured printed
image.
4. Device according to one of the preceding claims, characterized in that the
transport element (7, 16, 54) forms a transport section (17) between a
container inlet (6) and a container outlet (12), the containers (2) being
moved on said transport section during the printing.
5. Device according to one of the preceding claims, characterized in that a
plurality of printing stations (8, 55) for one container (2) in each case is
provided on the transport element (7, 16, 54).
6. Device according to Claim 5, characterized in that each printing station (8)
provided on the transport element (7, 16, 54) has at least one container
support (9) for the receiving of one container (2).
7. Device according to one of the preceding claims, characterized in that a
device (11, 20) for drying the printing ink applied onto the container
surface or the relevant part printed image is associated with each print
head (10.1-10.5, 18.1-18.6, 19, 57.1-57.5) or with a group of print heads.
8. Device according to one of the preceding claims, characterized in that an
independent printing group (10, 10a) with a plurality of print heads (10.1-
10.5) is associated with each printing station (8) on the transport element
(7, 16), and in that the print heads (10.1-10.5) are provided on the
transport element so as to be adjustable or switchable further for the part
print change.
9. Device according to Claim 8, characterized in that the print heads (10.1-
10.5) are adjustable or switchable on the transport element (7, 16) in the
direction of transport (R, TS) and in opposition to the direction of transport
(R, TS).
10. Device according to one of the preceding claims, characterized in that the
print heads (10.1-10.5) of each printing station (8) are provided on the
transport element (7) so as to be pivotable for the part print change,
preferably about an axis that is offset relative to the axis of the respective
container.
11. Device according to one of the preceding Claims, characterized in that
where there is an endlessly rotatingly driveable transport element (7, 16,
54) the printing groups (10, 10a, 18, 18a, 57) are positioned such that at
least at the print heads (10.1 - 16.1; 19) located in the print position the
discharging of the printing ink is supported by centrifugal forces generated
by the movement of the transport element (7, 16, 54).
12. Device according to Claim 11, characterized in that the print heads (10.1 —
10.5, 18.1 - 18.6, 19, 57.1 - 57.5) located in the printing position are
positioned with their print nozzles that create the print within the path of
movement of the containers (2).
13. Device according to one of the preceding Claims, characterized in that an
independent device (11) for drying the printing ink that has been applied
onto the outer surface of the container is provided for each printing station
(8, 55).
14. Device according to one of the preceding Claims, characterized in that
where there is a plurality of container supports (9) provided on the
transport element (7, 16) or of printing stations (8) formed by said
container supports, at least one printing unit or printing group (18, 18a)
common to all the printing stations is provided, past which the containers
(2) are moved and which has at least two print heads (19) for generating
different part printed images and, in a synchronous manner with the
movement of the transport element (7, 16), is entrainable with the
transport element in a floating manner in one operating stroke (TR1) out of
an initial position and is movable back into the initial position in one return
stroke (TR2) in opposition to the direction of transport (R, TS) of the
transport element (7, 16) so that in each operating stroke at least one
container (2) located at a printing station is printed with the associated part
image.
15. Device according to Claim 14, characterized in that the distance
between the at least two print heads (21) is identical to the distance
between the printing stations (8) or container supports (9) on the
transport element (7, 16).
16. Device according to Claim 14 or 15, characterized in that the printing
group (18, 18a) for each part printed image has at least one print head
unit (18.1-18.6) with at least two print heads (19) for the simultaneous
printing of at least two containers (2).
17. Device according to Claim 16, characterized in that the distance
between the print heads (19) at the printing group (18, 18a) in the
direction of transport (R, TS) of the transport element (7, 16) is
identical to the distance between the printing stations (8) or container
supports (9) on the transport element (7, 16).
18. Device according to one of Claims 14-17, characterized in that the at
least one printing group (18, 18a) is pivotable by a stroke that
corresponds to a machine spacing out of the initial position into the end
position and out of said end position back into the initial position, and in
that the machine spacing is identical to the distance between axes or
the angular separation of two adjacent printing stations (8) or container
supports (9) on the transport element (7, 16) multiplied by the number
of print heads (19) on each print head unit (18.1 - 18.6).
19. Device according to one of Claims 14-18, characterized in that a
device (20) for drying or setting the printing ink is provided for each
print head (19) of the print head units (18.1 - 18.6).
20. Device according to Claim 19, characterized in that the devices (20) for
drying the printing ink are switchable on and switchable off.
21. Device according to one of the preceding claims, characterized in that
the at least one floating printing unit or printing group (18) is provided
inside and/or outside the rotatably driveable transport element (7, 16).
22. Device according to one of the preceding claims, characterized in that
where there is a plurality of container supports (55) provided on the
transport element (54) or printing stations formed by said container
supports, at least one common printing group or printing unit (57) is
provided for all the printing stations, said printing group or printing unit
having at least two print head groups, each with at least two print
heads (57.1 - 57.5) per print head group for generating different part
printed images and, during the printing stage for generating each part
printed image, being entrained in the same direction and in a
synchronous manner with the movement of the transport element (54),
such that in each printing stage at least one print head (57.1 -57.5) of
each print head group is situated in a printing position at a container
(2), and in that for the print head change, the movement of the printing
unit (57) or of the print heads (57.1 -57.5) can be slowed down or
accelerated in such a manner and after the print head change can be
synchronised again in such a manner with the movement of the
transport element (54) that after the print head change a print head
(57.1 -57.5) of each print head group is once again situated in a
printing position with the respective container (2).
23. Device according to Claim 22, characterized in that the transport
element (54) is a rotating transport element, preferably a rotor (54).
24. Device according to Claim 22 or 23, characterized in that the print
heads (57.1 - 57.5) of the printing unit (57) are moveable in a
circulating manner on a movement path that is closed per se.
25. Device according to one of Claims 22 - 24, characterized in that the
print heads (57.1 -57.5) are provided on a rotatably driveable print
head support (56).
26. Device according to one of Claims 22 - 25, characterized in that the
distance between the print heads (57.1 - 57.5) in the direction of
movement of the printing unit (57) or of the print heads (57.1 -57.5)
corresponds to the reciprocal distance between the container supports
(55) or between the printing stations formed by said container supports
in such a manner that during each printing stage, each print head (57.1
-57.5) is situated in the printing position with reference to a printing
station or with reference to a container (2) positioned at that location.
27. Device according to one of Claims 22 - 26, characterized in that the
number of print heads (57.1 - 57.5) is identical to the number of
container supports (55) or of the printing stations formed by said
container supports.
28. Device according to one of Claims 22 - 27, characterized in that the
number of printing stations (57.1 - 57.5) is an integer multiple of the
number of container supports (55) or of the printing stations formed by
said container supports on the transport element (54).
29. Device according to one of Claims 22 - 28, characterized in that the
number of container supports (55) or of the print stations formed by said
container supports on the transport element (54) is an integer multiple of
the print heads (57.1 - 57.5) of the printing unit (57).
30. Device for printing, preferably for printing containers (2) in multiple
colours by means of a transfer print, said device including at least one
printing group (39, 51) with at least two print heads (39.1 -39.5; 51.1 —
51. 5) that operate according to the ink jet print head principle for
generating printed images, each consisting of at least two part printed
images, onto transfer pads (37, 48) which are moved past the printing
group (39, 51), said printed images being transferred onto the containers
(2) by rolling off the respective containers (2) at a transfer region, a
container conveyor (34, 44) by means of which the containers (2) are
moved in a direction of transport (R, TS) during the printing and an
auxiliary conveyor (38, 49) with a plurality of transfer pads (37, 48) that
are moved with the auxiliary conveyor (38, 39) on a path of movement
that is closed per se, characterized in that the container conveyor (34,
44) is a rotor (34) that is rotatably driven about a vertical machine axis
(MA) and the auxiliary conveyor is a wheel-shaped or drum-shaped
element (38) that is rotatably driveable about the machine axis (MA).
31. Device for printing, preferably for printing containers (2) in multiple
colours by means of a transfer print, said device including at least one
printing group (39, 51) with at least two print heads (39.1 -39.5; 51.1 -
51. 5) that operate according to the ink jet print head principle for
generating printed images, each consisting of at least two part printed
images, onto transfer surfaces of transfer pads (37, 48) which are moved
past the printing group (39, 51), said printed images being transferred
onto the containers (2) by rolling off the containers (2) at a transfer
region, a container transport element (34, 44) by means of which the
containers (2) are moved in a direction of transport (R, TS) during the
printing and an auxiliary conveyor (38, 49) with a plurality of transfer
pads (37, 48) that are moved with the auxiliary conveyor (38, 49) on a
path of movement that is closed per se, characterized in that the transfer
pads (37, 48) are provided so as to be controllable or pivotable on the
auxiliary conveyor (38, 49) in such a manner that they are oriented with
their transfer surface in a horizontal or substantially horizontal manner
when passing the printing group (39, 51) and abut against the outside
surface of the upright containers (2) with their transfer surface at the
printing position.
32. Device according to Claim 31, characterized in that when passing the
printing group (51), the transfer pads (48) are positioned below the
printing group or the print heads (51.1 - 51.5).
33. Device according to one of Claims 30 - 32, characterized in that a
cleaning station (40, 50) for the transfer pads (37, 48) is provided on the
circumferential path of the auxiliary conveyor (38, 49) upstream of the
printing group (39, 51).
34. Device according to one of Claims 23 - 25, characterized in that the
auxiliary conveyor (49) is a transport element rotating about at least one
horizontal axis, for example a transport wheel or a transport element
forming at least one vertical or substantially vertical loop.
35. Device according to one of Claims 30 - 34, characterized in that the
auxiliary conveyor (38, 49) is driven such that the transfer pads (37, 48)
move parallel to the direction of transport (R, TS) of the container
conveyor (34, 44) at the transfer region, but at a speed that deviates
from the transport speed of the container transport element (34, 44) with
regard to direction and/or magnitude.
36. Device according to one of Claims 31 - 35, characterized in that the
container transport element is a rotor (7) that is rotatably driveable about
a vertical machine axis or a turntable or a transport system (16) with at
least one transport element that forms a closed loop.
37. Device according to one of the preceding claims, characterized in that at
least one print head (10.5, 19) is used for applying a sealing or
protective coating onto the respective printed image.
38. Device according to one of the preceding claims, characterized in that in
the direction of transport (R, TS) following the transfer region on the
periphery of the container transport element (34, 44) but not being
entrained by said container transport element, there is provided at least
one device (41, 52) for applying a sealing or protective coating onto the
respective printed image and/or a device (42, 53) for drying the
respective printed image and/or the sealing and protective coating, in
each case with the container (2) rotated about the container axis.
39. Device according to one of the preceding claims, characterized in that a
control system (14, 43) for checking the respective container print is
provided at the container transport element (7, 16, 34, 44) upstream of
the container outlet (12, 35).
40. Device according to one of the preceding claims, characterized by a
conveyor (3, 30) that includes a corona tunnel (4, 31) for supplying the
containers (2) to the container inlet (6, 33) of the device (1, 1a — 1f).
41. Method for printing, in particular for printing containers in multiple colours
on their container outer surface with a print that is formed by at least one
printed image, by using at least one printing group (10, 10a, 18, 18a, 57)
with at least two print heads (10.1 - 10.5, 18.1 - 18.6, 19, 57.1 - 57.5)
that operate according to the ink jet print head principle for generating
part printed images of the printed image to be applied to the outer
surface of the container in at least one printing step, wherein the
containers (2) are moved on a transport element (7, 16, 54) in a direction
of transport (R, TS) during the printing and the printing groups (10, 10a,
18, 18a, 57) are entrained with the transport element (7, 16, 54) at least
during part of the at least one printing step, characterized in that after
printing a part image and before printing another part image a print head
change is carried out in such a manner that a print head (10.1 - 10.5,
18.1 - 18.6, 19, 57.1 - 57.5) that is situated in a printing position at the
relevant container (2) is moved out of the printing position and another
print head (10.1 -10.5, 18.1 -18.6, 19, 57.1 -57.5) is moved into the
printing position.
42. Method according to Claim 41, characterized in that during the printing
the containers are rotated about their container axes, for example by an
angle of 360°.
43. Method according to Claim 41 or 42, characterized in that during the
printing steps, part printed images are applied in the form of different
colour sets of a multi-coloured printed image and/or in the form of at
least one sealing or protective coating covering the printed image.
44. Method according to one of the preceding claims, characterized in that
the printing of the containers (2) is effected in each case at a printing
station that is provided with a plurality of printing stations (8) of a similar
type on the transport element (7, 16), wherein an independent printing
group (10, 10a) with a plurality of print heads (10.1 - 10.5) is associated
with each printing station (8), and in that for the respective part print
change or print head change, the print heads (10.1 - 10.5) are moved
relative to the printing station or to its printing position in the direction of
transport (R, TS) and in opposition to the direction of transport (R, TS)
and/or are pivoted or rotated about an axis, for example about an axis
that is offset relative to the axis of the respective container (2).
45. Method according to one of the preceding claims, characterized in that
the print heads (10.1 - 10.5, 18.1 - 18.6, 19, 57.1 - 57.5) are each
positioned during the printing of the part printed images such that the
applying of the printing ink and/or the sealing or protective coating are
supported by centrifugal forces that are generated by the movement of
the transport element (7).
46. Method according to one of the preceding claims, characterized in that
the respective part printed image and/or the sealing or protective coating
are dried directly after generation.
47. Method according to one of the preceding claims, characterized in that
the printing ink forming the respective part printed image or a compound
forming the sealing or protective coating is continuously dried as it is
being discharged.
48. Method according to Claim 46 or 47, characterized in that the drying is
effected by application of energy, for example by heating and/or by UV
light.
49. Method according to one of the preceding claims, characterized in that
where there is a plurality of printing positions formed on the transport
element (7, 16), the printing of the containers (2) is effected with at least
one printing unit (18, 18a) that is common to all printing positions, the
containers to be printed being moved past said printing unit, which has
at least two print heads (19), and in that the printing unit (18, 18a), for
generating in each case a part image with the print heads, is entrained
with the transport element (7, 16) out of an initial position in one
operating stroke (TR1) and in one return stroke (TR) is moved back into
the initial position in opposition to the direction of transport (RTS) of the
transport element (7, 16).
50. Method according to Claim 49, characterized in that the printing unit (18,
18a) is moved back into the initial position after each operating stroke
(TR1) in such a manner that a container (2) is located at a print head
(19) that is situated in the printing position.
51. Method according to Claim 49 or 50, characterized in that at least two
containers (2) are printed with different part printed images after each
operating stroke (TR1).
52. Method according to one of Claims 50 - 51, characterized in that in each
operating stroke, in each case at least two container groups, each
comprising at least two containers (2), are printed with different part
printed images.
53. Method according to one of Claims 49 - 52, characterized in that in each
operating stroke, a first part printed image is applied with at least one
print head (19) on at least one container not yet printed with the printing
unit or printing group (18, 18a), and another part printed image is applied
with at least one second print head on at least one container that is
already provided with a part printed image, and in that after each
operating stroke (TR1), the printing unit (18, 18a) is moved back into the
initial position in such a manner that at the at least one first print head
(19) in each case a container (2) not yet printed with the printing unit or
printing group (18, 18a) is situated in the printing position and at the at
least one other print head (19) a container (2) already printed with the
printing unit or printing group (18, 18a) is situated in the printing position.
54. Method according to one of Claims 49 - 53, characterized in that the
printing unit or printing group (18, 18a) in each operating stroke (TR1) or
return stroke (TR2) is pivoted by a stroke that is identical to the distance
between axes or to the angular separation between two printing
positions (9) on the transport element (16, 17) or an integer multiple
thereof.
55. Method according to one of the preceding claims, characterized in that
where there is a plurality of container supports (55) provided on the
transport element (54) or of print stations formed by said container
supports, at least one printing group or printing unit (57) common to all
printing stations is used that has at least two print head groups, each
with at least two print heads (57.1 - 57.5) per print head group for
generating different part printed images, in that printing unit (57) during
each printing stage for generating each part printed image is entrained in
the same direction and in a synchronous manner with the movement of
the transport element (54) such that in each printing stage at least one
print head (57.1 -57.5) of each print head group is situated in a printing
position at a container (2), and in that for the print head change, the
movement of the printing unit (57) or of the printing heads (57.1 - 57.5)
is slowed down or accelerated in such a manner and after the print head
change is once again synchronized with the movement of the transport
element (54) in such a manner that, after the print head change, a print
head (57.1 - 57.5) of each print head group is once again situated in a
printing position with the respective container (2).
56. Method according to Claim 55, characterized in that the slowing down or
accelerating is effected by temporarily superposing the movement of the
printing unit (57) or of the print heads (57.1 - 57.5) that is synchronous
with the transport element (54), with another movement component in
opposition to or in the direction of transport (R) of the transport element
(54).
57. Method according to Claim 55 or 56, characterized in that the print
heads (57.1 - 57.5) of the printing unit (57) are moved in a rotating
manner on a path of movement that is closed per se.
58. Method for printing, preferably for printing containers (2) in multiple
colours by means of a transfer print by using a printing group (39, 51)
with at least two print heads (39.1 -39.5; 51.1 - 51. 5) that operate
according to the ink jet print head principle, with which print heads the
printed images, consisting of at least two part printed images, are
applied to transfer pads (37, 48) that are moved past the printing group
(39, 51), said printed images then being transferred onto the containers
(2) by rolling off the containers (2) at the transfer pads, wherein during
the printing the containers (2) are moved on a container transport
element (34, 44) and the transfer pads are moved with an auxiliary
conveyor (38, 49), characterized in that the containers (2) are moved
with the container conveyor (34, 44) and also the transfer pads (37, 48)
with the auxiliary conveyor (38, 49) on a circular path about a vertical
axis.
59. Method according to Claim 58, characterized in that the transfer pads
are moved on a circular path of movement within the circular path of
movement of the containers (2).
60. Method for printing, preferably for multiple printing, preferably for multiple
printing of containers (2) by means of a transfer print by using at least
one printing group (39, 41) with at least two print heads (39.1 -39.5; 51.1
- 51. 5) that operate according to the ink jet print head principle, with
which print heads the printed images, consisting of at least two part
printed images, are applied to transfer pads (37, 48) that are moved past
the printing group (39, 51), said printed images then being transferred
onto the containers (2) by rolling off the containers (2) at the transfer
pads, characterized in that the printing of the transfer pads (37, 48) is
effected in a printing position in which the transfer surface of the
respective transfer pad (37, 48) is positioned in a horizontal or
substantially horizontal plane, and in that, before the transfer of the
respective printed image, the transfer pads (37, 48) are pivoted into a
transfer position in which the respective transfer surface abuts against
the outside surface of the upright containers (2).
61. Method according to Claim 60, characterized in that during the printing,
the containers (2) are moved on a container transport element (34, 44)
and the transfer pads are moved with an auxiliary conveyor (38, 49).
62. Method according to Claim 60 or 61, characterized in that, before the
transfer of the respective printed image, the transfer pads (37, 48) are
pivoted into a horizontal or substantially horizontal transfer position.
63. Method according to one of Claims 60 - 62, characterized in that the
printing of the transfer pads (37, 48) is effected with print heads (51.1 -
51.5) positioned above the respective transfer surface.
64. Method according to one of Claims 60 - 63, characterized in that the
pivoting of the transfer pads (37, 48) is effected about at least one axis
parallel or substantially parallel to the direction of their movement.
65. Method according to one of Claims 58 - 64, characterized in that the
transfer pads (37, 48) for the transferring of the printed images are
moved parallel to the direction of transport (R, TS) of the containers (2),
but at a speed that deviates from the transport speed of the containers
(2) with regard to direction and/or magnitude.
66. Method according to one of the preceding Claims 41 - 65, characterized
in that the containers (2) are treated in a corona tunnel (4, 31) before the
printing.

The invention relates to a device and a method for printing
containers, especially in multiple colours, on at least one
outer surface of the container, using a print formed by at least
one printed image, at least one printing group provided with
print heads operating according to the ink jet printing
principle, for producing partial printed images of the printed
image to be applied to the outer surface of the container in at
least one printing step, and a transport element for moving
the container during the printing in a transport direction.
The printing groups are moved with the transport element at
least one printing step.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=f69pV/0Uq1Y6dqjlawOROQ==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

272897

Indian Patent Application Number

112/KOLNP/2010

PG Journal Number

19/2016

Publication Date

06-May-2016

Grant Date

02-May-2016

Date of Filing

11-Jan-2010

Name of Patentee

KHS GMBH

Applicant Address

JUCHOSTRASSE 20, 44143 DORTMUND, GERMANY

Inventors:

#	Inventor's Name	Inventor's Address
1	SCHACH, MARTIN	STEINKUHLSTRASSE 15, 44799 BOCHUM

PCT International Classification Number

B41J 3/407

PCT International Application Number

PCT/EP2008/005711

PCT International Filing date

2008-07-12

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102007036752.1	2007-08-03	Germany