EP2459385B1 - Equipment for printing on containers - Google Patents

Description

The invention relates to a system for printing on containers, such as bottles, with a printed image (font and / or image pattern) on at least one printing machine with at least one print head, as well as to a thus executed method.

It is known that labels such as bottles and packages are labeled so that consumer information can be displayed. It is also known that with inkjet printers markings or other information are applied to the packaging, which allow an individualization that does not allow the label printing. Such printing systems work monochrome and are limited to a few printing dots / lines.

It is also known that printing processes and systems are used which allow printing heads of different manufacturers to print widths of up to 174 mm per print head. These printheads work in a single color, with several colors, several printheads one after the other and offset accordingly to arrange so that depending on the number of colors, an always uniform distance between the individual pressure points is achieved. This is possible with an adjustment to a machine with several printheads arranged one after the other. The packaging material is guided past the print heads at a constant speed. The performance of such a machine is therefore dependent on the printing speed of a respective printhead. This is indeed practical for absorbent packaging materials. For other materials, such as metals, glass or plastic, the paint must either be dried by heat or cured by UV or electron beam crosslinking. This process is after printing apply to any ink, increasing the length of such machines. If you want to increase the power, so either multiple printing systems to switch in parallel or to choose a different arrangement.

There is already a proposal to arrange on a carousel a plurality of holders for packaging material to be printed circular and to rotate the individual packaging on the individual station during the rotation of the carousel itself and thus to pass the surface of the package at several disposed at each station and aligned printheads , The disadvantage here is that with surfaces that require the use of UV-curing or by electron beam to be cured inks, no intermediate drying or crosslinking of the individual printing inks is possible.

Therefore, there is still the proposal to apply each color on individual, successively arranged in series carousels, the drying / crosslinking can be done on the transfer between the carousels. Provided in this embodiment, the container or the packaging on a belt in each case on the belt in a division, which is equal to the pitch of the machine to fix, clamp independent transport unit and thus centered successively to drive through the various successively arranged carousels , This holder would be designed as a pivot bearing, so that drive the container on the carousels and thus be passed to the individual print head of the respective color with the entire surface.

From the US 2006/0144261 A1 For example, there is known a linear printing apparatus for containers in which the containers are fixed and linearly transported between a head holder and a bottom holder, which are then moved downstream past a local printing unit. It is proposed, by means of a sensor, the distance between the printheads of To determine printing unit to the container surface, or to control the movement of the printheads perpendicular to the surface of the container to be printed.

It has also been proposed to clamp containers in individual holders, each holder rotatably receiving the container and having a mark for the 0 degree angle. The containers are thus clamped Individually transported and received in nachelnandergeschalteten printing machines with the holder. The holder and the receptacle is designed so that a centering of the holder in the machine is so accurate that the container is aligned to match the print image of the corresponding printhead and by the 0 degree mark accordingly in the axis of rotation. However, the requirements for centering and the accuracy of the guide, so that a high-quality print image is achieved, it is high and complex, since when pulling and braking different tensile forces act on the belt and also temperature fluctuations could occur, both of which lead to exceeding tolerances, the are not compensable. It should also be kept in mind that if the container is a bottle, it is usually difficult, since printing normally takes place after filling. The mass of the holder itself is added to this weight. The genuineness of the centering requirement becomes clear when you know that with standard 600 dpi print quality the pressure points are 0.042 mm apart and the heavy bottle holder must therefore be permanently aligned to 1/100 mm , With processing quantities of, for example, 36,000 bottles / h in the beverage industry, more than 200 million bottles per year thus pass through such a machine. The wear is enormous and affects the print quality considerably.
Object of the present invention is to propose a system of the type mentioned, with the help of which a high pressure performance can be achieved with reliable function and high print quality.

This object is achieved by the plant of claim 1.

In this way it is ensured that with little time a perfect print image can be applied to the container.

In the system according to the invention, at least one further printing press of the previously indicated type for printing with the same and different color of the first printing machine will be arranged downstream, so that differently colored printed images can be produced with the same advantage.

The at least two printing presses work together in terms of control technology in order to apply the multicolored printed image to the container.

To further improve the accuracy of the printed image is also proposed that in the at least one printing press on the respective container a mark is printed, by means of which a positioning and / or alignment of the print head of at least one further printing machine.

The marking may be in addition to the printed image, for example, as an irregular polygon, in particular isosceles triangle, may be provided, but a part of the printed image may also serve as a marker itself.

Hereby, the marking may be transmitted via a camera or e.g. Sensors having image processing device are detected, which outputs a corresponding output signal to the printhead to position it correctly.

Advantageously, with the help of the data obtained from the marking, for example, the print head of a downstream printing press for printing with the same or a further color on the print image of a previous printing press, for example by means of stepper or servo motors according to altitude, container spacing and / or tilt set.

In a practical embodiment of the system according to the invention, the container to be printed, for example, is e.g. by means of an inlet star made of e.g. linear conveyor introduced into a station of a carousel (ie a rotary treatment machine), centered in a clamping device and rotated for printing in rotation.

In this case, with the help of the data obtained from the marking, the angle of rotation of the container can be determined at which the printing begins.

Advantageously, during a revolution of the carousel, the respective container undergoes a revolution in its station while being printed on its surface.

Thereafter, the respective printed container can be transported out of the carousel by means of an outlet star and, if necessary, the applied color, e.g. in a UV tunnel, before being optionally in another and possibly similar trained printing machine for further printing, for. is introduced in the same way.

Accordingly, the invention can also be carried out on linear machines.

Other objects, features, advantages and applications of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. All described and / or illustrated features, alone or in any combination form the subject matter of the invention, regardless of their summary in individual claims and / or their dependency.

Fig. 1a bis 1d

die prinzipiellen Positioniermöglichkeiten des Druckkopfes der Druckmaschine einer erfindungsgemäßen Anlage relativ zu einem, im dargestellten Fall als Flasche ausgebildeten, Behälter,

Fig. 2

eine mögliche Anordnung von beispielsweise drei Druckmaschinen in einer erfindungsgemäßen Anlage hintereinander,

Fig. 3a und 3b

eine zentrierende Klemmeinrichtung für zwei Behälter unterschiedlicher Größe in der Station zum Bedrucken einer erfindungsgemäßen Anlage,

Fig. 4a und 4b

einen möglichen Aufbau einer Einrichtung zum Verstellen des Druckkopfes in verschiedenen Achsen im Schnitt und in Draufsicht,

Fig. 5a und 5b

Beispiele möglicher Markierungen auf dem Behälter zur Bestimmung der Positionierung des Druckkopfes, und

Fig. 6a und 6b

ein Vergleich der Abwicklung eines Druckbildes einer ersten Druckmaschine auf einem Behältnis in einer senkrechten Achslage und auf einer zweiten Druckmaschine bei einer sich dort beim Einspannen zufällig ergebenden Schieflage.

Show it:

Fig. 1a to 1d

the basic positioning possibilities of the print head of the printing press of a system according to the invention relative to a container, in the case illustrated as a bottle, container,

Fig. 2

a possible arrangement of, for example, three printing presses in a system according to the invention in succession,

Fig. 3a and 3b

a centering clamping device for two containers of different sizes in the station for printing a system according to the invention,

Fig. 4a and 4b

a possible structure of a device for adjusting the print head in different axes in section and in plan view,

Fig. 5a and 5b

Examples of possible markings on the container for determining the positioning of the print head, and

Fig. 6a and 6b

a comparison of the processing of a printed image of a first printing machine on a container in a vertical axis position and on a second printing machine at a randomly there during clamping resulting skew.

Fig. 1 shows where in principle, for example, a bottle-shaped container B can be printed by a print head 1, ie in particular on the stomach (print image area F _B ) and the neck (print image area F _H ). The container B is during printing, for example, on a turntable 2 (see. Fig. 3a and 3b ) and is rotated there during the printing process. The printed image D is by means of nozzles 10 (see. Fig. 4a and 4b ) of the print head 1 exiting paint in the area of the print image area F _B and / or F _H applied to the surface of the container B. The position of the print head 1 according to location coordinates and angular position is automatically determined by the shape and position of the container B, which detects with the aid of a camera or an image processing device, which in turn emits corresponding Ausrichtsignale via a control device to the print head 1. The print image area F of the container B may be at different levels from the turntable 2, so that the print head 1 in its height position (z-axis) is adjustable. The distance (x-axis) of the print head 1 from the container axis A is also adjustable, as is the angular position of the print head 1 as a function of the container shape and the orientation of the container. For example, in a bottle, the bottoms and bottoms of the bottle may not be in the vertical or same position as in the previous press. Also, therefore, an alignment in the angles α ₁ and α _{2 is} provided (see Fig. 1 d) ,

Fig. 2 illustrates a system according to the invention for printing on containers B with three consecutively connected rotary treatment machines (carousels) 3, each with multiple stations 13. The unprinted container B are first brought from a linear conveyor line by means of an infeed star 4 in the first carousel 3 and there on each one the stations 13 on a turntable 2 (see Fig. 3a and 3b ) centered clamped. During printing, the containers B rotate about their axis A such that they undergo one revolution during one revolution of the carousel 3. The printed container B are then transported by means of an outlet star 5 back into the conveyor line and reach after drying or curing of the color, for example in a UV tunnel 6 to a second carousel 3 having printing machine for the application of the next color. A container B from the fourth station 13 of the first printing press can arrive, for example, on the fifth station 13 of the second or the seventh station 13 of the then following third printing press. Since a printing process including container orientation takes about 2 seconds, the carousels at 10 containers / sec = 36,000 containers / h, ie about 8 to 9 stations 13 including entry / exit. It is impossible to align the tolerances of six printing presses with six-color printing and 9 stations each, ie 72 stations in total, in such a way that all containers can accurately record the print image D at 1/100 mm. Therefore, it is important that the distance of the print head 1 from the turntable center (in the x direction) is adjustable.

The Fig. 3a and 3b illustrate the entrapment of different containers B between a lower turntable 2 and an adjustable centering counter-holder 7. One then differentiates an adjustment in the x-axis and the z-axis and the angle α ₁ and α ₂ when switching to another container B or another position of the print image in height and a fine adjustment during the printing process to compensate for unwanted tolerance violations. The first adjustment essentially occurs when printing on different containers. The travels are possibly long between the position of the printed image area, for example in a short bottle and a high bottle or a thin bottle with a small diameter and a thick bottle with a large diameter. The fine adjustment, which takes place during printing, usually requires only a few tenths of a millimeter adjustment.

The Fig. 4a and 4b illustrate a possible structure for the adjustment of the print head 1 in the different axes. In Fig. 4a the guide of the z-axis and the spindle drive for height adjustment is not shown. Fig. 4b shows the same arrangement in plan view.

Fig. 5a shows as marker M for the positioning of the print head 1 for location coordinates and / or angular position an isosceles triangle. The triangle points can be outside or inside the print image area F. Among other things, they serve to calculate the inclination of the container B and the height of the printed image surface F above the turntable 2. When two such triangles have been applied offset by 90 ° on the container B, the angles α ₁ and α ₂ (see. Fig. 1d as well as 4a and 4b).

Fig. 5b illustrates an example in which individual points of the print image D itself are used as a marker to determine the positioning of the print head 1 relative to the container B and to deliver a corresponding adjustment signal to the print head 1.

Since, for example, to be printed containers such as bottles can be out of round and eccentric state of the container, such as a bottle on the turntable 2, whereby the container does not rotate about its own axis but about the turntable, it is possible according to the distance between Print head 1 and to be printed surface to change during a revolution of the container, since the print image D according to Fig. 6a on a subsequent printing station as an image according to Fig. 6b represents.

According to the invention, it is further proposed to constantly measure the distance between the print head 1 and the container surface by means of sensors in order to readjust the distance value in the x-axis and the angles α ₁ and α ₂ during the rotation of the container. This is always an equal distance to the surface to be printed, even if, for example, non-round bottles or oval bottles are to be printed.

LIST OF REFERENCE NUMBERS

1

printhead

2

turntable

3

carousel

4

feed star

5

outlet star

6

Drying / curing (UV tunnel)

7

backstop

8th

rack

9

Carriage (x-axis)

10

jet

11

Guide for z-axis

12

Spindle nut for z-axis

13

station

A

container axis

B

container

D

print image

F _B

Printed image of the abdomen

F _H

Printed image of the neck

M

mark

α ₁

tilt angle

α ₂

tilt angle

Claims (11)

1. Equipment for printing on containers (B), such as bottles, having a printed design (D) on at least one printing machine having a plurality of stations (13) and having one or two print heads (1) per station (13), wherein the at least one print head (1) is automatically adjustable by means of a preferably electrical controller and an adjustment value from the controller moves the print head (1) according to spatial coordinates and/or an angular position into a position that is determined or calculated by means of a measuring device having sensors from the surface contour and the position relative to the print head (1) of the container (B) to be printed upon, characterised in that
   the first printing machine is followed by at least one further printing machine of the aforementioned type for printing with the same or different colour and these are rotary printing machines,
   which operate interlinked to each other by control, and wherein the sensors are arranged on the printing machine such that the distance between print head (1) and container surface can be continually measured.
2. Equipment according to claim 1, characterised in that, in at least one printing machine, a marking (M) can be printed upon the container (B), said marking enabling the positioning and/or alignment of the print head (1) in at least of one further printing machine.
3. Equipment according to any one of the preceding claims, characterised in that it comprises an infeed starwheel by means of which the respective container to be printed upon can be introduced e.g. from a linear conveying device into the station (13) of a carousel (3), where, in a clamping device (2, 7), it can be centred and placed into rotation.
4. Equipment according to any of claims 1 to 3, characterised in that the respective container (B), during a revolution of the carousel (3), can be rotated at least by one rotation in its station (13), while its surface is being printed upon.
5. Equipment according to any one of claims 1 to 4, characterised in that the respective printed container (B) can, by means of an outfeed starwheel (5), be transported out of the carousel (3) and the ink applied can be cured e.g. in a UV tunnel (6), and the container can then be introduced into a further and, if required, similarly designed printing machine for further printing.
6. Method for printing on containers, characterised in that equipment according to any one of claims 1 to 5 is used, and wherein, in at least one printing machine, a marking (M) is printed upon the container (B), with the print head (1) in at least one further printing machine being positioned and/or aligned using said marking.
7. Method according to claim 6, characterised in that the marking (M) is an irregular polygon, in particular an isosceles triangle, printed in addition to the printed design (D), or a part of the printed design (D) itself serves as a marking (M).
8. Method according to claim 6 or 7, characterised in that the marking (M) is captured by means of a camera, or an image processing device having sensors, which passes a corresponding output signal to the print head (1).
9. Method according to any one of claims 6 to 8, characterised in that, during printing, the distance between print head (1) and container surface is continually measured by means of sensors and the distance value in the x axis and the inclination angles (α₁, α₂) of the container surface are readjusted during the rotation of the container.
10. Method according to any one of claims 6 to 9, characterised in that, using the data derived from the marking (M), the print head (1) of a downstream printing machine is adjusted for printing with the same or a further colour on the printed design (D) of a preceding printing machine e.g. by means of step motors or servo motors according to elevation, distance of the container (B) and/or inclination of the container (B).
11. Method according to any one of claims 6 to 10, characterised in that, in case of at least one rotation of the container (B) for full printing or in case of a rotation by few angular degrees in order to fulfill the printing after alignment of the container (B) in case of an outer circumferential surface to be only partially printed upon using the data derived from the marking (M), the rotation angle of the container (B) is determined at which the printing begins or ends.

Images