EP2250026B2 - Printing apparatus for printing bottles or similar containers - Google Patents

Abstract

The invention relates to a printing apparatus for printing bottles or similar containers, having several printing positions on a transport element, which can be driven in rotation, by which the printing positions and/or the containers are moved on a closed path of movement between at least one container take-up and at least one container drop, having rotating print heads for applying at least one print image, preferably multi-color, onto a region to be printed on the external container surface of the containers, in the event of relative movement of the external container surface and at least one print head, wherein at least one enclosure is present, into which each of the containers, which are provided at a print position, is housed during the printing process with at least the region to be printed thereof.

Description

The invention relates to a printing device according to the preamble of claim 1 and in particular to a printing device for printing on containers using at least one electronically or digitally controllable printhead.

The printing and in particular direct printing of containers is basically known, especially in the form that the applied to the respective container preferably multicolored printed image, for example, similar to a conventional label forms an essential element of the equipment of each container. In many cases electrostatic printheads, such as e.g. Ink jet printheads or printheads, known as "Tonejet", ie, printheads that operate on the ink jet printing or Tonejet principle and each having a plurality of individual nozzles, which on an active printhead side in a printhead longitudinal axis in at least one row arranged following each other and are individually controllable for dispensing ink, printing ink and / or, for example, coatings and protective coatings. For the purposes of the invention, "ink", "printing ink" or the like is generally to be understood as a resource with which the respective print image with different quality features is produced using the print head.

A particular problem, in particular in printing devices for printing on containers using printheads, which operate on the inkjet printing or Tonejet principle, is that during the printing process each part of the ink does not reach the area to be printed on the container outer surface, but in the surrounding air is sprayed and forms an aerosol of finely divided ink or ink particles. These sprayed ink or ink particles then undesirably deposit, i.a. on elements of the respective printing device and thereby cause contamination, which can be removed again only with a high cleaning effort.

It is also problematic in known printing devices that especially at high powers, the containers are moved during printing at high transport speeds, with the result of strong air turbulence or turbulence on the containers, resulting in blurring of the ink and errors or quality losses Printing leads.

The object of the invention is to provide a printing device which avoids such disadvantages and without the risk of contamination of the printing device by printing ink ensures high quality printed images. To solve this problem, a printing device according to the patent claim 1 is formed.

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination are fundamentally the subject of the invention, regardless of their summary in the claims or their dependency. Also, the content of the claims is made an integral part of the description.

Fig. 1

In vereinfachter Darstellung und in Draufsicht eine Druckvorrichtung zum direkten Bedrucken von Behältern, beispielsweise mit nach dem Tinten- strahldruck- oder Tonejet-Prinzip arbeitenden Druckköpfen;

Fig. 2

in vereinfachter perspektivischer Darstellung mehrere der am Umfang ei- nes Rotors vorgesehenen Druckpositionen;

Fig. 3

in vergrößerter perspektivischer Darstellung mehrere der am Umfang des Rotors vorgesehenen Druckpositionen;

Fig. 4

in vergrößerter Teildarstellung und in Draufsicht zwei der am Umfang des Rotors vorgesehenen Druckpositionen;

Fig. 5

Eine Darstellung ähnlich Fig. 2 bei einer weiteren Ausführungsform der Erfindung.

The invention will be explained below with reference to the figures of embodiments. This shows:

Fig. 1

In a simplified representation and in plan view of a printing device for direct printing of containers, for example, with working according to the ink jet printing or Tonejet principle printheads;

Fig. 2

in a simplified perspective view of several provided on the circumference of a rotor printing positions;

Fig. 3

in an enlarged perspective view of several provided on the circumference of the rotor printing positions;

Fig. 4

in an enlarged partial view and in plan view of two provided on the circumference of the rotor printing positions;

Fig. 5

A representation similar Fig. 2 in a further embodiment of the invention.

The in the Figures 1-4 generally designated 1 printing device is used for direct printing of containers, which are in the illustrated embodiment bottles and in particular PET bottles 2.

The printing device 1 comprises u. a. a pressure gyro or rotor 3, which can be driven around a vertical machine axis Z (arrow A) and has a plurality of treatment or printing positions 4 distributed around its circumference at uniform angular intervals about the machine axis Z.

The bottles 2 to be printed will stand upright to a container inlet of the printing apparatus 1 having an inlet star 5 via an outer conveyor 6, i.e., an outer feed 6. Oriented with their bottle axis in the vertical direction and supplied in the conveying direction B of the conveyor 6 consecutively and arrive via the inlet level 5 to a respective printing position 4. The printed bottles 2 are taken from the respective printing position 4 on a discharge star 7 having a container outlet and an outer Transporter 8 fed in its conveying direction C for further use.

Each printing position essentially comprises a container carrier, which in the illustrated Embodiment of a bottle or container plate 9 is formed and controlled about its container plate axis Y, which is oriented parallel to the machine axis Z, rotatable or pivotable (arrow D). Furthermore, each printing position 4 comprises a stamp 10, with which the respective bottle 2 is secured against overturning after the transfer to the printing position 4, by clamping between the container plate 9 and the stamp 10. Each stamp 10 is for securing and releasing the respective bottle 2 controlled in turntable axis Y and can be moved up.

The printing position 4 further comprise in each case a sleeve-like housing or protective sleeve 11 which is formed in each case in three parts in the printing device 1 and in the closed state, the bottle 2 provided at the relevant printing position 4 encloses and receives at its entire height at a distance. Each protective sleeve 11 comprises a housing or protective sleeve element 11.1, which, for example, rotationally fixed, i. not rotatably provided with the respective container plate 9 on the rotor 3 and with the axis of curvature of its partially circular cylindrical inner and outer surface is arranged coaxially with the container axis Y of the associated container plate, and offset relative to the machine axis Z relative to the associated container plate axis Y radially inward. At the upper edge of each protective sleeve element 11.1 is connected to a circular disk-shaped housing or protective sleeve element 11.2, which is arranged coaxially with the container plate axis Y arranged part of the punch 10 or is connected thereto.

Each protective sleeve 11 further comprises a housing or protective sleeve element 11.3, which is offset relative to the machine axis Z opposite container plate axis Y radially outward and controlled to close and open the respective protective sleeve 11 in an axial direction parallel to the machine axis Z and can be moved up, this in the FIG. 2 indicated by the arrows E and F.

At each printing position 4 are in the inner sleeve member 11.1 in the direction of rotation D of the container plate 9 successively a printhead 12 for generating a multi-color print image on a provided for applying this print image area of the outer surface of the respective bottle 2 and on this printhead 12 following a means 13 for fixing provided the printing ink. The printhead 12 consists of a plurality of individual printheads, each of which can be controlled digitally or electronically, e.g. operate on the Tonejet principle or method, i. Each individual print head has a plurality of nozzle openings for discharging the respective printing ink, which are arranged in at least one row parallel or substantially parallel to the container plate axis Y and individually controllable for discharging the ink. The print head 12 is arranged so that the printing direction of the print head 12, d. H. the direction in which the ink is ejected from the print head 12 or the individual print heads, is oriented radially or substantially radially to the machine axis Z, so that the application of the ink to the respective bottle 2 is supported by the centrifugal forces generated in rotating rotor 3 ,

To produce the different color separations, the individual print heads contain printing inks of different colors, for example red, blue, yellow and black. The respective print image or its individual color sets are generated by driving the print head 12 or the individual print heads according to an electronically stored in a computer print template, namely on the respective container plate 3 to the container plate axis Y and thus controlled to the bottle axis bottle 2 rotated.

In particular, the printing of the bottles 2 is carried out e.g. such that each bottle 2 with open protective sleeve 11, d. H. is passed to the relevant printing position 4 in accordance with raised protective sleeve element 11.3. Immediately upon this handover, i. then, if the respective bottle 2 is still held in the inlet star 5, by lowering the punch 10, the securing of the bottle 2 against falling as well as the centering of the bottle 2 in the form that the bottle axis coaxially with the container plate axis Y of the corresponding container dish. 9 is arranged. On a first, subsequent to the container inlet angular ranges rotational movement of the rotor 3 is then carried out closing the respective protective sleeve 11 by controlled lowering of the protective sleeve element 11.3. On a further angular range of rotation of the rotor 3 success with closed protective sleeve 11, the printing of the respective bottle 2, for example in the form that at each full revolution of the bottle 2 about its axis a bottle color set of the print image with the push button 12 and applied to the color set associated single print head and this color set is then fixed with the device 13, for example by drying or a corresponding energy input in the form of heat energy, eg hot air or infrared radiation, UV radiation, microwave energy, etc. Thereafter, in another rotation of the bottle 2 about its bottle axis, the application of the next color set to the print head 12 and the subsequent fixing of this color set to the device 13, etc ,

In principle, other methods of applying the individual color sets of the multicolored printed image are also possible, for example in such a way that in a single printing process the multicolor print image is already printed with one or more printhead-oriented printheads, known as wet in wet printing. is generated and then fixed to the device 13.

Regardless of the type of printing process, a part of the ink does not reach the respective surface of the bottles 2 to be printed, but forms part of it the air surrounding the bottle 2 contains an aerosol which sprays the ink and would lead to severe contamination of the printing device 1 with printing ink. In order to avoid this, the printing of each bottle 2 takes place when the protective sleeve 11 is closed. For aspirating sprayed ink, a suction device is provided which, in the illustrated embodiment, comprises a plurality of suction tubes 14 opening into the interior of the respective protective sleeve 11 on the upper protective sleeve element 11.2. These are each connected via manifolds or - lines 15 with a common for all printing positions 4 suction device. In order to facilitate the suction of the sprayed ink, each protective sleeve 11 is formed so that at the bottom of the closed protective sleeve a slot-shaped opening for an air flow (supply air) remains in the protective sleeve interior.

By sucking off the sprayed into the interior of the protective sleeve 11 printing ink is in particular also prevents ink particles accumulate uncontrollably on the outer surface of the respective bottle 2 and thus may affect the visual appearance of the bottle 2.

In order to reduce the proportion of sprayed ink and to increase the quality or sharpness of the printed image at least one example, rod-shaped electrode 16 is provided on the inside of each protective sleeve member 11.1 in the direction of rotation D of the container plate 9 in front of the print head 12, at least before the beginning of the each printing operation and during the printing process with an increased DC voltage is applied, for example, with a DC voltage of up to 30 kV. By this high voltage, a static charge of the respective bottle 2 takes place at its area to be printed, so that with opposite polarity of the print head 12 and the individual print heads, for example at ground potential, the ink particles in the electrostatic field between the print head and the bottle targeted to the local pressure range accelerated. Furthermore, an ion cloud is generated by the voltage at the at least one electrode s 16, are charged and removed by the floating ink particles.

By housing the bottles 2 within the protective sleeves 11 during printing but not only contamination of the printing device 1 is avoided by sprayed ink, but by the housing and the quality of the respective print image impairing air turbulence on the bottles 2 are avoided. It should be noted that, in particular when the printing device 1 is operated at high power (high number of printed bottles 2 per unit of time), the rotor 3 rotates at high speed about the machine axis Z. This results in each printing position 4 a considerable flow of air, as in the FIG. 4 indicated by the arrows 17. Due to the closed protective sleeve 11, the bottles 2 or pressure areas are protected during printing against this air flow 17. This prevents a deflection of the fired ink drop from its trajectory, thus achieving the desired drop placement and achieving the quality of the given print image. The ratio of drop speed to printing speed specified by the printhead manufacturer is thus not adversely affected by externally acting air streams 17.

It was assumed above that when the respective bottle 2 is transferred from the inlet star 5 to a printing position or when the printed bottle 2 is taken from a printing position 4 on the outlet star 7 (in each case with the protective sleeve 11 open) the respective stamp 10 is lowered or is raised. In principle, there is also the possibility that in the case of non-movable punches 10 the bottles 2 are raised and pressed on the infeed star 5 and lowered on the delivery star 7 by the punches 10, in each case with the container plate 9 and with the protective sleeve 11 open.

It has also been assumed above that the protective sleeve element 11.3 is lowered or raised in a controlled manner for opening and closing the respective protective sleeve 11. Other designs are conceivable. For example, it is possible for the respective protective sleeve element 11.3. to lower the protective sleeve 11 and raise it to close the protective sleeve 11 and / or pivotally provide for opening and closing the protective sleeve 11. Furthermore, it is also possible to lower the respective protective sleeve 11 in total for Einhausen the respective bottle 2 for printing and for releasing the bottle 2 after printing and raise.

The FIG. 5 shows in a representation similar FIG. 2 a printing device 1a, which differs from the printing device 1 essentially only in that for the enclosure during printing in each case a closed, designed as a hollow cylinder with a hollow cylindrical inner and outer surface protective sleeve 11a is provided. At the container inlet or inlet star 5 then each transferred to a container plate 9 bottle 2 is introduced by controlled lifting of the container plate 9 from below into the relevant protective sleeve 11a. At the container outlet or at the outlet star 7 each printed bottle 2 is moved out by controlled lowering of the associated container plate 9 down from the protective sleeve 11 a, so that they can then be taken over by the starter 7 and forwarded to the outer conveyor 8.

The protective sleeve 11 and in particular their protective sleeve elements 11.1 and 11.3 and the protective sleeve 11a are made for example of plastic or cardboard or cardboard, as disposable elements that are replaced by fresh protective sleeve elements 11 and 11a at high pollution by sprayed or sprayed ink ,

It was assumed above that a gap is formed at the lower edge of the respective protective sleeve 11 or 11a, through which supply air can flow into the protective sleeve interior during the aspiration of the sprayed or sprayed printing ink. In addition to or instead of this, other openings for the supply air may be formed, in particular also openings in the side wall or in the jacket of the respective protective sleeve 11 or 11a. In this case, it is possible, in particular, to make the protective sleeves 11 and 11a double-walled, at least in some areas, with a perforated wall on the inside, so that the supply air required for aspiration does not pass through a gap at the lower edge of the respective protective sleeve 11 or 11a flows into the protective sleeve interior, but over the gap between the outer and inner wall member and the openings provided in the inner wall member.

The invention has been described above by means of exemplary embodiments. It is understood that numerous changes and modifications are possible without thereby departing from the inventive concept underlying the invention.

LIST OF REFERENCE NUMBERS

1, 1a

Printing device for printing on containers

2

bottle

3

rotor

4

print position

5

feed star

6

external transporter

7

outlet star

8th

external transporter

9

Bottle or container dish

10

stamp

11, 11a

protective sleeve

11.1, 11.2, 11.3

sleeve elements

12

printhead

13

Device for fixing the printing ink

14

suction tube

15

manifold

16

rod-shaped electrode

17

airflow

A

Direction of rotation of the rotor 3

B, C

Transport direction of the outer conveyor 6 and 8 respectively

D

Direction of rotation of the container dish 9

e

Lowering pit of the protective sleeve element 11.3

F

Opening pit of the protective sleeve element 11.3

G, H

Movement stroke of the respective container dish 9

Y

Container plate axis

Z

machine axis

Claims (7)

1. Printing apparatus for printing bottles or similar containers (2), having a plurality of printing positions (4) on a transport element (3), which can be driven in rotation, by which the printing positions (4) and the containers (2) are moved on a closed path of movement between at least one container take-up (5) and at least one container drop (7), having print heads (12) for applying at least one print image, preferably multi-colour, onto a region to be printed on the external container surface of the containers (2), namely during relative movement of the respective external container surface and at least one print head (12), characterised in that each printing position (4) is assigned a separate enclosure (11, 11a) in which each container (2) provided at a printing position (4) is housed during the printing process with at least the region to be printed thereof.
2. Printing apparatus according to claim 1, characterised by means for sucking sprayed and/or injected printing ink out of the enclosure (11, 11a).
3. Printing apparatus according to claim 1 or 2, characterised in that the print heads (12) are electronic or digital print heads, preferably print heads operating according to the inkjet printing principle or tonejet principle.
4. Printing apparatus according to any one of the preceding claims, characterised in that a container support, for example in the form of a container or bottle plate (9), is provided at each printing position (4), and in that the container support (9) and/or the at least one print head (12) can be rotated or swivelled in a controlled manner about a container support axis (Y) in order to generate the relative movement during printing.
5. Printing apparatus according to any one of the preceding claims, characterised in that the enclosure (11, 11a) or at least one sub-element (11.3) of the enclosure (11) is designed to be movable, for example for a controlled raising or lowering and/or rotation and/or swivelling, in order to house and release the respective container (2).
6. Printing apparatus according to any one of the preceding claims, characterised in that the at least one enclosure (11, 11a) is made from cardboard or paperboard or plastic.
7. Printing apparatus according to any one of the preceding claims, characterised in that the at least one enclosure (11, 11a) is of double-walled design at least in a sub-region, for example with an inner wall having multiple perforations.

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