Method and device for printing onto containers made of glass

Abstract

A method and a device for printing onto containers, in particular bottles, made of glass are described. Containers that have been heated and coated by hot end coating are received from a transport section and transferred to a printing machine. The containers are cooled to a printing temperature in the region of the transport section and/or of the printing machine are provided with a printed image in the printing maching by direct printing. This allows for high-quality direct printing with sufficient resistance to mechanical stresses without cold end coating of the containers prior to the direct printing and/or without the resulting effort of improving the adhesive action of the print or of removing the cold end coating in the print region at least in part.

Claims

1. Method for printing onto containers made of glass in which said containers in a state heated by hot end coating are transferred to a transport section and are transported thereon to a printing machine, and where said containers are cooled down to a printing temperature in the region of said transport section and/or of said printing machine and are then provided with a printed image in said printing machine by direct printing.

2. Method according to claim 1, where said containers are transported separated and at a distance throughout from one another from an infeed region of said transport section to the direct printing.

3. Method according to claim 1, where said containers are guided and/or held on said transport section, while leaving a lateral wall region free that is provided for said printed image.

4. Method according to claim 1, where said containers have at least one rubbing edge formed from glass which keeps lateral wall regions of said containers for receiving said printed image at a distance from one another when said containers contact each other, or a rubbing edge corresponding functionally in this regard is applied by the direct printing.

5. Method according to a claim 1, where said containers are cooled substantially to said print temperature in a cooling tunnel.

6. Method according to claim 1, where the direct printing comprises the application of a primer layer onto a hot end coating layer produced by the hot end coating.

7. Method according to claim 1, where said printed image is produced by way of inkjet printing.

8. Method according to claim 6, where the direct printing comprises the application of a transparent protective layer onto said printed image.

9. Method according to claim 1, where said containers transported separated are combined by machine downstream of the direct printing to form packs and/or by palletizing for multiple transport.

10. Method for producing containers made of glass for bottling beverages, comprising melt-forming said containers, their hot end coating immediately downstream and the immediately downstream execution of the method according to claim 1.

11. Container made of glass comprising: a container body made of silicate glass, a hot end coating layer formed thereon, and a printed image applied thereonto in direct printing directly or by way of an adhesion layer, including according to the method according to claim 1.

12. Device for direct printing onto containers made of glass following their hot end coating, comprising: a printing machine for direct printing onto said containers; at least one transport section for separated transport of said hot-end-coated containers from an outfeed region of a hot end coating unit to said printing machine; and a cooling tunnel arranged in the region of said transport section for cooling down said containers, heated as a result of the hot end coating, to a printing temperature for direct printing.

13. Device according to claim 12, furthermore comprising a pretreatment unit arranged in the region of said transport section and/or said of printing machine for preparing a coating layer produced on said containers with hot end coating by way of plasma treatment and/or flame treatment and/or for spraying on an adhesion layer for the respective subsequent direct printing.

14. Device according to claim 12, where said transport section comprises grippers that are movable in the direction of transport for a neck finish portion and/or base portion of said containers, including while leaving free a wall region of said containers that is intended for said printed image.

15. Device for the production of containers made of glass comprising said device according to claim 12 and upstream thereof a glass machine for melt-forming said containers and a downstream hot end coating unit for producing a hot end coating layer on said containers.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0046] Preferred embodiments of the invention shall be illustrated by way of drawings, where:

[0047] FIG. 1 shows a schematic top view onto an embodiment of the device;

[0048] FIG. 2 shows a schematic side view of a container on the transport section;

[0049] FIG. 3 shows a schematic illustration of the method with direct printing based on UV-curing printing colors; and

[0050] FIG. 4 shows a schematic illustration of the method with direct printing based on solvent-based printing colors.

DETAILED DESCRIPTION

[0051] As can be seen in FIG. 1, device 1 for direct printing onto containers 2 made of a silicate glass following their hot end coating comprises a printing machine 3 for direct printing of a printed image 4 (shown by way of example in FIG. 2) (in the sense of a label) onto containers 2 by way of an ink jet, a transport section 5 for separated transport of hot-end-coated containers 2 to printing machine 3, and a cooling tunnel 6 arranged in the region of transport section 5 for cooling down containers 2, which have been heated to an initial temperature TA as a result of hot end coating, substantially to a printing temperature TD for direct printing, for example, to room temperature.

[0052] Transport section 5 is configured for the separated transport of containers 2 at distances 7 from one another or corresponding gaps therebetween, respectively. This prevents that containers 2 collide with one another in the wall regions provided for printed image 4 and can be mechanically damaged during transport.

[0053] Transport section 5 receives containers 2 from a hot end coating unit 8 (only indicated schematically) which is arranged in the outfeed region of a glass machine 9 for forming containers 2. Glass machine 9 can operate in a manner known in principle for the production of hollow glass using the blow-blow or press-blow method. It is also indicated schematically that glass machine 9 can be configured as a rotary machine.

[0054] Containers 2 are preferably bottles and are made of silicate glass. Its hot end coating is a method that is known in principle and is therefore not explained in detail.

[0055] The decisive factor for the invention is that containers 2 are transported in a suitable manner, in particular separated, to printing machine 3 immediately after their hot end coating and, on the way there, are cooled down from their initial temperature TA (defined in the outfeed of hot end coating unit 8 and/or in an infeed region 5a of transport section 5) to printing temperature TD. In principle, it would also be conceivable that an additional temperature correction to printing temperature TD is carried out immediately prior to the first printing step in the region of printing machine 3.

[0056] As can be seen from FIG. 2, transport section 5 in the simplest case comprises a conveyor belt 5b on which containers 2 preferably stand upright at a distance 7 from one another. As an alternative or in addition, endlessly circulating transport mechanisms with grippers 5c, corresponding long-stator systems, or similar transport mechanisms are also conceivable. Direction of transport 5d of transport section 5 is furthermore shown.

[0057] Bottom-free transport or transport in which containers 2 are only held at a neck region 2a and/or a base/heel region 2b would therefore also be possible in order to free a wall region 2c of containers 2 provided for printed image 4 or to keep it free from contact with grippers 5c, respectively. This is also indicated schematically in FIG. 2.

[0058] It is also shown there, not to scale, that containers 2 preferably each comprise at least one rubbing edge (scuffing edge) 2d which can be made of glass, for example, as part of the container body (shown) or can be printed on by direct printing by printing machine 3 (not shown).

[0059] FIG. 1 shows, by way of example, that printing machine 3 can comprise several printing units 10 for applying printing colors/inks, intermediate curing units 11 for the printing colors/inks, and a final curing unit 12 for the printing colors/inks.

[0060] In the case of inkjet printing using UV-curing printing colors/inks, intermediate curing units 11 are configured as so-called UV pinning units and final curing unit 12 as UV radiators, which is known in principle.

[0061] In the case of ink jet printing using solvent-based printing colors/inks, intermediate curing units 11 and final curing unit 12 are preferably configured for heat drying on the basis of radiant heaters.

[0062] Printing units 10 can be configured, for example, to print white ink and chromatic colors, such as CMYK, successively in the direction of transport (arrow). Intermediate curing units 11 are then used for the respective partial curing of the printing color/ink applied immediately beforehand and promote their spreading to a suitable degree.

[0063] At least a pretreatment unit 13, for example, for flame pretreatment or plasma pretreatment of containers 2 and/or a priming unit 14 for applying a functional primer (base coat) in the sense of a bonding agent or the like can optionally be arranged in the region of transport section 5 (not shown) and/or of printing machine 3 (shown).

[0064] Printing machine 3 can furthermore have a printing unit 15 for applying a transparent protective layer (for example a protective lacquer) onto printed image 4.

[0065] It is also indicated schematically in FIG. 1 that a drying tunnel 16 can be present downstream of printing machine 3 and in particular immediately adjoining for drying printed image 4 on containers 2 in a suitable manner, in particular as a result of direct printing using solvent-based printing colors/inks. Their complete drying/curing can be promoted or accelerated in this manner. This is particularly advantageous if the drying/final curing of such printing colors/inks with final curing unit 12 (by way of a radiant heater) in the region of printing machine 3 is not possible or only insufficiently possible.

[0066] A packing machine 17 can be present downstream of printing machine 3 for combining the previously still separated containers 2 to form packs 18 and/or on pallets 19 and to thus supply them to multiple transport.

[0067] Steps of the method according to the invention are shown schematically in FIG. 3 according to a first embodiment.

[0068] According thereto, method 21 according to the first embodiment comprises a first step 22 in which hot-end-coated containers 2 are cooled down from initial temperature TA to printing temperature TD, preferably during the ongoing transport and while maintaining an individual transport at a distance 7 from one another.

[0069] The containers can thereafter be pretreated in an optional step 23, for example, by flame pretreatment and/or plasma pretreatment.

[0070] Alternatively or additionally, containers 2 can be coated in an optional step 24 with a functional primer in the sense of a bonding agent.

[0071] Printed image 4 is then printed directly, first in a step 25, in that the basic color white is printed on and intermediately cured/cured in part by way of UV pinning.

[0072] The direct print of printed image 4 is thereafter continued in that the printing colors of a color model, such as CMYK, and optionally so-called spot colors are respectively printed and intermediately cured by way of UV pinning. Chromatic colors applied in this manner can have a mechanical protective function for the later transport and use of containers 2 against scratching, abrasion, or the like.

[0073] If the chromatic colors do not have such a protective function or if such a protective function is to be reinforced, then a transparent protective layer (protective lacquer) can be printed on in an optional step 27. The protective layer is then preferably also UV-curing.

[0074] In a step 28, the final UV curing of the print layers (printed image 4 and optionally protective layer) takes place thereafter.

[0075] As an alternative to step 27, an organic protective layer could be subsequently applied in the sense of a cold end coating in step 29 in order to increase the mechanical resistance of containers 2 and of printed image 4.

[0076] FIG. 4 shows a corresponding sequence of method 31 according to a second embodiment based on printing colors/inks that cure by evaporating a solvent such as water.

[0077] In this case, steps 32, 33, and 34 correspond to steps 22, 23 and 24 of first embodiment 21, so that no further explanation is presently required.

[0078] Steps 35 and 36 also correspond substantially to steps 25 and 26 of first embodiment 21 with regard to the color design of printed image 4. However, the intermediate curing that is obligatory in UV direct printing is replaced by optional heat drying of the respective printing colors/inks by way of infrared radiation (radiant heaters), likewise the final curing of the printing colors/inks.

[0079] Alternatively, it would also be conceivable in the case of solvent-based printing colors/inks to set the printing temperature TD to a value that is suitably raised above room temperature so that additional heat drying after the individual printing steps could be dispensed with.

[0080] A transparent protective layer (protective lacquer) is applied in step 37.

[0081] Printed image 4 and/or the protective layer applied immediately beforehand is finally cured in step 38. This can take place, for example, in a heat tunnel (not shown).

[0082] As an alternative to step 37, an organic protective layer could be applied in the sense of a cold end coating in step 39 for increasing the mechanical resistance of containers 2 and of printed image 4.

[0083] After all printed layers (printed image 4 and optionally protective layer) have cured, the then sufficiently mechanically protected containers 2 can be transferred from separated transport to multiple transport in a step 30 (first embodiment 21) or 40 (second embodiment 31). This is done, for example, by combining containers 2 to form packs 18 and/or on pallets 19.

[0084] Methods 21, 31 described represent a considerable simplification compared to printing methods in which direct printing takes place onto containers after their cold end coating. Accordingly, raw materials can be saved and the number of method steps can be reduced. This leads to savings in production time, material, and energy costs.