Method and device for treating containers

Abstract

A method for treating containers in which, at a treatment station, the containers are provided on container outer surfaces thereof with a print that including a colorant. The colorant can be dye or ink. The method includes, at a treatment station, processing the colorant by irradiating the containers with non-thermal energy radiation. Processing the colorant includes drying or curing it. The method also includes decontaminating a region of the containers with the same radiation, either by disinfecting or sterilizing it. The region includes either or both a container opening and a container inner surface.

Claims

1. A method comprising treating a container that has had an image digitally printed on an outer surface thereof, said image comprising a colorant, said colorant comprising at least one of printing dye and printing ink, wherein treating comprises simultaneously processing said colorant and decontaminating a region of said container using the same radiation, said radiation being non-thermal energy radiation, wherein processing comprises at least one of drying and curing, wherein decontaminating comprises at least one of sterilizing and disinfecting, and wherein said region comprises said container's inner surface.

2. The method of claim 1, wherein using the same radiation comprises using electron radiation.

3. The method of claim 1, further comprising causing a common treatment module to receive said container from a last printing module of a plurality of printing modules in a treatment section, each of said printing modules being separate and distinct from said treatment module and from each other, said treatment module and said printing modules comprising identical base units, each of which has a housing upon whose top is a rotor that can be driven to rotate about a vertical machine axis, wherein said rotor of said treatment module comprises a periphery that carries treatment stations to which bottles are transferred through a container inlet of said treatment module, wherein said container moves through said treatment section in a meandering path that comprises multiple curved paths, each of which corresponds to one of said modules.

4. The method of claim 1, further comprising pre-curing said colorant before said processing and said decontaminating.

5. The method of claim 1, further comprising pre-drying said colorant before said processing and said decontaminating.

6. The method of claim 1, further comprising pretreating said outer surface of said container using said radiation.

7. The method of claim 1, further comprising forming a silica layer on said outer surface.

8. The method of claim 1, further comprising receiving said container at a treatment module that is one of plural modules along a transport section through which said container moves along a meandering transport path, said plural modules comprising plural printing modules, wherein said modules are separate and distinct from each other, wherein each of said modules comprises a rotor.

9. The method of claim 1, further comprising at least one of charging and purging said container with a shielding gas while concurrently processing said colorant and decontaminating said region of said container, said shielding gas being at a temperature below that of said container.

10. The method of claim 1, wherein concurrently processing said colorant and decontaminating said region of said container using the same radiation is carried out in an atmosphere having an oxygen partial-pressure of between 0.5% and 0.1% of total pressure.

11. The method of claim 1, further comprising, causing a centering-and-holding element to carry a vertically-oriented container, causing said centering-and-holding element, with said vertically-oriented container, to move along a plurality of meandering transport paths from one module to a subsequent module of a treatment section, thereby bringing said container into and out of treatment modules that follow one another along a transport direction, and swiveling said container about a container axis thereof while processing and decontaminating, wherein said centering-and-holding element remains with said container while said container is outside any module.

12. The method of claim 1, further comprising, prior to said container having been formed from a preform, using said radiation to sterilize a centering-and-holding element and causing said centering-and-holding element to return to a module to pick up said preform, to hold said preform in a vertical orientation, and to bring said preform toward another module at which said concurrent decontaminating and processing take place.

13. The method of claim 1, further comprising holding said container with a centering-and-holding element during said processing and decontaminating, causing said centering-and-holding element to release said container, after said centering-and-holding element has released said container, uncoupling said centering-and-holding element from a transport system, and returning said centering-and-holding element, as an independent unit, to an entrance of a treatment section through which containers move along a meandering transport path into and out of plural treatment modules.

14. The method of claim 1, wherein said radiation is microwave radiation.

15. The method of claim 1, wherein said decontaminating comprises causing said radiation to propagate through free space outside said container in a direction towards said region, wherein said radiation originates at a source that is outside said container.

16. The method of claim 1, wherein said decontaminating comprises causing radiation to propagate through free space from a source of said radiation towards said region, wherein said source lies directly above an opening of said container.

17. The method of claim 1, further comprising splitting oxygen molecules above said outer surface prior to printing on said outer surface.

18. The method of claim 1, further comprising, causing a centering-and-holding element to carry a vertically-oriented container, causing said centering-and-holding element, with said vertically-oriented container, to moves along a plurality of meandering transport paths from one module to a subsequent module of a treatment section, thereby bringing said container into and out of treatment modules that follow one another along a transport direction, and causing said container to experience vertical relative motion while processing and decontaminating.

19. The method of claim 1, wherein said container stands on a turntable that rotates said container about a vertical axis thereof.

20. The method of claim 1, further comprising selecting said radiation to have a wavelength that is absorbed by oxygen gas.

21. The method of claim 1, further comprising selecting said radiation to have a wavelength that is sufficiently small to split oxygen molecules.

22. The method of claim 1, further comprising suppressing diffusion of oxygen into said container.

23. An apparatus comprising a treatment or transport section for a container, said treatment or transport section comprising a printing module for digitally printing on an outer surface of said container using a colorant and a treatment module for simultaneously processing said colorant and decontaminating an inner surface of said container using the same radiation, wherein said colorant comprises at least one of printing dye and printing ink, wherein processing said colorant comprises at least one of drying said colorant and curing said colorant, and wherein decontaminating said container comprises at least one of disinfecting and sterilizing said container.

24. The apparatus of claim 23, further comprising a pre-treatment module for pre-processing said colorant, wherein said pre-treatment module is separate and distinct from said printing module and said treatment module, wherein pre-processing comprises at least one of pre-drying said colorant, pre-curing said colorant, and pre-treating said container on a region of said outer surface.

25. The apparatus of claim 23, further comprising a pre-treatment module upstream of said treatment module, said pre-treatment module being configured to cause a silica layer to adhere to said outer surface.

26. The apparatus of claim 23, wherein said radiation comprises ultraviolet radiation.

27. The apparatus of claim 26, wherein said ultraviolet radiation has a wavelength between 170 nanometers and 280 nanometers.

28. The apparatus of claim 23, wherein there exist first and second UV sources, wherein said first UV source is directed downward onto a region of an opening of said container and said second UV source is directed towards a side of said container.

29. The apparatus of claim 23, wherein said treatment module is maintained at positive pressure during operation thereof and wherein gas from inside said treatment module flows out of said treatment module.

30. An apparatus for treating a container, said apparatus comprising means for transporting and treating said container, said means for transporting and treating comprising means for digitally printing on an outer surface of said container using a colorant and means for simultaneously decontaminating an interior surface of said container and processing said colorant with non-thermal radiation.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is explained in detail below through the use of embodiment examples with reference to the figures. In the figures:

(2) FIG. 1 shows a simplified perspective depiction of an installation for the treatment of containers in the form of bottles (PET bottles in this case) in simplified perspective depiction;

(3) FIG. 2 shows a schematic depiction of the transport path of the respective container through the installation of FIG. 1;

(4) FIG. 3 shows a perspective depiction of one of the treatment modules of the installation of FIG. 1, in this case for example for the simultaneous curing of the print applied to the respective bottle and for sterilizing the bottles in the region of at least their bottle mouth;

(5) FIG. 4 shows a schematic, perspective depiction of one of the treatment positions of the treatment module of FIG. 3;

(6) FIG. 5 shows a depiction similar to FIG. 4 but in another embodiment of the treatment module;

(7) FIG. 6 shows a simplified depiction in plan view of an installation for producing the containers in the form of plastic bottles, for example in the form of PET bottles by stretch or blow molding, and also for the subsequent treating of the produced containers;

(8) FIGS. 7 and 8 show a centering and holding element for use with the device of FIG. 6 with a preform and/or a partially depicted bottle.

DETAILED DESCRIPTION

(9) FIG. 1 shows a treatment section 1 that is used for treating containers in the form of bottles 2. A first conveyor 3 provides the treatment section 1 with hanging bottles 2. These bottles 2 hang from, or are suspended by, a flange or neck ring 2.2 formed below the bottle's opening 2.1, as can be seen in FIG. 4.

(10) As shown in FIG. 2, the bottles 2 move along a transport direction A through the treatment section 1 along a meandering transport path 4. Treated bottles 2 leave the treatment section 1 at a container outlet again suspended from a second conveyor 5. The second conveyor 5 conveys bottles 2 to a further use, for example to a filling machine.

(11) The bottles 2 are produced from preforms by stretch or blow molding in a blow-molding machine 6. The method is of course not confined to PET bottles but can also be used for other plastic bottles, such as those made from PE, PP, PLA or PHB.

(12) In the illustrated embodiment, the treatment section 1 is a modular treatment section having first through eighth treatment modules 7.1-7.8 that follow one another along the transport direction A according to the sequence defined by their reference numbers. As a result, n.sup.th treatment module 7.n passes bottles 2 to (n+1).sup.th treatment module 7. (n+1) along the transport path 4.

(13) The treatment modules 7.1-7.8 have identical base units. Each base unit has a lower module housing or machine housing 8 upon whose top is provided a rotor 9 that can be driven to rotate about a vertical machine axis. The periphery of the rotor 9 carries treatment stations 10 to which bottles 2 are transferred through a container inlet of the treatment module 7.1-7.8.

(14) The treatment stations 10 treat bottles as the rotor 9 carries them along an angular range of its rotary motion. Bottles are then individually passed on to a treatment station 10 of a subsequent treatment module 7.2-7.8 or to the second conveyor 5.

(15) A controller drives the rotors 9 of the treatment modules 7.1-7.8 that succeed one another in the transport direction A. It does so by driving them synchronously and with the same rotary or angular speed, but in opposite directions B, C, as shown in FIG. 1.

(16) The treatment stations 10 of treatment modules 7.1-7.8 are matched to the respective treatment by corresponding units and/or functional elements provided on the base unit.

(17) In the case of the embodiment depicted in FIG. 1, the treatment stations 10 of the first treatment module 7.1 are configured for a pretreatment of bottles 2.

(18) The treatment stations 10 of the second through seventh treatment modules 7.2-7.7 act as print modules for the printing, preferably digital printing, of bottles 2 on their outer surfaces. Printing includes applying polychrome printed images to outer surfaces of the bottles 2, and preferably in different regions of that outer surface. Accordingly the treatment stations 10 of the second through seventh treatment modules 7.2-7.7 have inkjet printing heads.

(19) The eighth treatment module 7.8 acts as a drying and sterilization module for the drying or curing of the printed images while concurrently sterilizing the bottles 2, at least on a region thereof on which such sterilizing is necessary because of the production of bottles 2, the source materials used for their production, and/or the handling of bottles 2 after their production.

(20) In the illustrated embodiment, UV radiation both cures the print and sterilizes the bottles. The UV spectrum is optimized for curing the printing dye and for killing bacteria. A useful UV spectrum includes clearly pronounced peak at a wavelength of approximately 270 nanometers.

(21) FIG. 3 shows the eighth treatment module 7.8 in detail. Each treatment station 10, shown in close-up in FIG. 4, has a fork-like or gripper-like container carrier 11 that suspends a bottle 2 by its neck ring 2.2. Each treatment station 10 also has a first UV source 12 and a second UV source 13.

(22) The first UV source 12 is located above the container carrier 11, and hence above opening 2.1 of the bottle 2 present at treatment station 10. The first UV source 12 has a UV lamp that is directed downwards onto the region of the bottle opening 2.1.

(23) The second UV source 13 lies radially on the inside relative to a machine axis of the eighth treatment module 7.8. The second UV source 13 emits light onto surface of bottle 2. This second UV source 13 cures and dries the printing dye. There The bottle 2 rests on a turntable 14 that can be rotated bout a vertical axis thereof to rotate the bottle 2.

(24) The container carrier 11, the first and second UV sources 12, 13 and the turntable 14 are provided on a housing 15 on which the container carrier 11 and the first UV source 12 can be moved vertically up and down along a vertical direction D. The housing 15 accommodates components needed to operate and/or cool the UV lamps of the first and second UV sources 12, 13. The container carrier 11, the first and second UV sources 12, 13, the turntable 14, and the housing 15 collectively define an assembly unit 16 that is provided on the rotor 9. The assembly unit 16 forms one of the treatment stations 10 of the eighth treatment module 7.8.

(25) To promote smooth acceptance and delivery of a bottle 2 at the transfer region between the seventh and eighth treatment modules 7.7, 7.8 and at the transfer region between the eighth treatment module 7.8 and the second conveyor 5, the container carrier 11 and the first UV source 12 are each raised and, during the treatment, lowered such that the bottle 2 stands upright on the turntable 14 with its base. The turntable 14 then rotates the bottle about the vertical turntable axis. This rotation permits the second UV source 13 to treat the entire periphery of the bottle 2. During this procedure, the container carrier 11 steadies the upright bottle 2 so that it does not fall over.

(26) In the preceding embodiment, the container carrier 11 and the first UV source 12 move up and down. However, it is also possible to instead move the turntable 14 vertically up and down to facilitate, in the manner mentioned above, smooth transfer and delivery of bottles 2 to and from respective treatment stations 10 on the one hand and on the other the rotation of bottles 2 about their vertical bottle axis during the treatment.

(27) In some embodiments, the treatment stations 10 only UV-sterilize bottles 2 the region of their bottle mouth opening 2.1. As a result, either the bottles 2 should be substantially sterile after they have been manufactured or the bottles 2 should be formed from sterile preforms. In either case, further handling on the transport path to a treatment section 1 or within a treatment section 1 should contaminate bottles 2 only in the region of their bottle mouth 2.1.

(28) In an alternative embodiment shown in FIG. 5, a treatment station 10a has a first UV source 12a above a container carrier 11 that is configured to emit UV radiation for sterilizing at least of the entire inner surface of a bottle 2. In this embodiment, during treatment, a UV lamp or light guide 17 extends through bottle opening 2.1 and into the interior of bottle 2. As was the case with the first embodiment, this embodiment also sterilizes bottles 2 and cures or dries a printed image 2.3 within the same treatment station 10a of the eighth treatment module 7.8, and preferably simultaneously.

(29) The treatment station 10a is particularly useful because, even transparent bottles 2 absorbs so much UV radiation that UV radiation cannot pass through the wall of the bottle and adequately sterilize the interior in any commercially viable way. In particular, the UV power and the time required to achieve adequate sterilization by a source outside the bottle 2 would be prohibitive.

(30) In some embodiments, the treatment module 10a is configured to sterilize both a bottle's inner surface its outer surface, particularly in the region of bottle opening 2.1 through the use of UV radiation.

(31) In some embodiments, lowering the container carrier 11 or raising the turntable 14 uncouples the 2 the bottle from the container carrier 11, thereby allowing it to be rotated about its bottle axis during the treatment. However, it is possible to uncouple the bottle in other ways. For example, the container carrier 11 can be configured to release a bottle 2 during treatment to permit the bottle to be rotated about its bottle axis. In other embodiments, the container carrier 11 is configured to actually bring about bottle's rotation during treatment.

(32) The first treatment module 7.1 is configured for a pretreatment of a bottle 2 so that the printing dye adheres better to the bottle's surface. This pretreatment is effected by irradiating surfaces that are to be subsequently printed with UV radiation.

(33) The improvement in the adhesion of the printing dye arises in part because UV radiation, and in particular, UV radiation having a wavelength of less than 240 nm, splits oxygen molecules close to the treated surfaces. This forms ozone that, together with the oxygen, absorbs UV quanta that have wavelengths below 240 nm. This process forms many radicals, such as COO*, *OH, CO*, and COOH*. It also forms radicals on the plastic chains of the material from which the bottles 2 are made. This bring about localized changes to the symmetry of the molecular structure. An effect of these localized changes is that of increasing the surface energy and improving the adhesion strength and wettability of the surfaces that are to be printed with printing dye. This pretreatment of bottles 2 with the UV radiation is preferably accompanied by a sterilization or disinfection of the outer surface of bottles 2.

(34) To achieve this pretreatment, the first treatment module 7.1 has treatment stations 10, 10a similar to those of the eighth treatment module 7.8 but with the omission of the first UV sources 12, 12a.

(35) Other treatment methods and appropriately configured treatment stations for improving the adhesion strength and wettability of the printed surfaces of bottles 2 are also possible for the first treatment module 7.1. In some embodiments, the first treatment module 7.1 has treatment stations 10 that carry out surface silicatizing of the bottles' surfaces by pyrolysis, for example flame pyrolysis. This generates a thin but very dense and firmly adhering silica layer with high surface energy. This silica layer provides high adhesion strength for a printing dye on the outer surface of respective bottle 2. In some embodiments, such a treatment station carries out flame treatment of bottles 2 using a suitable gas, for example propane and/or butane in the presence of an organic silicon compound, such as silane.

(36) Some embodiments of the first and eighth treatment stations 7.1, 7.8 achieve especially beneficial results by irradiating the bottles 2 with UV radiation in a low-oxygen, sterile inert gas atmosphere. Suitable inert gases include nitrogen, carbon dioxide, and any of the noble gases. This advantage arises because atmospheric oxygen inhibits the cross linking reaction and/or curing of common polymer printing dyes. The use of a low-oxygen inert gas atmosphere thus improves curing or drying times and the hard-drying of the printing dye.

(37) Another advantage of irradiating with a low-oxygen atmosphere is that when there is very little oxygen, there will also be very little ozone. This is of particular importance because the optimal wavelengths for UV sterilization are significantly below 240 nanometers. These wavelengths have a propensity for forming ozone.

(38) An oxygen-lean atmosphere thus makes it possible to use very short-wave UV radiation for a rapid and high quality UV sterilization. In particular, it becomes possible to use UV radiation having wavelengths between 170 and 280 nanometers, and in particular, those having wavelengths in a preferred range of between 170 and 220 nanometers. It would not be practical to use such short wavelengths in the presence of significant oxygen because UV radiation in the 170-200 nm range can only effectively propagate through an oxygen-rich atmosphere for 1 to 10 millimeters at best. In the case of UV radiation having a wavelength of 200 nm, the oxygen's partial pressure in the shielding gas atmosphere or inert gas atmosphere should be at most 0.5%, and preferably only 0.1% of total pressure.

(39) When a low-oxygen shielding gas or sterile gas atmosphere is used during UV sterilization and UV curing, the treatment stations 10 and 10a are disposed in an enclosure filled with the shielding or inert gas at a positive pressure sufficient to ensure that, at the inlet and outlet of the enclosure, inert gas flows out of the housing and into the surrounding area. This prevents ingress of oxygen into the enclosure.

(40) Some embodiments expose the surface and/or interior of the bottles 2 to a cooled process gas or inert gas during UV sterilization and UV curing. Among other things, such exposure reduces the thermal burden on bottles 2 during UV sterilization and UV curing and reduces emission of infrared radiation from bottles 2.

(41) Some embodiments introduce a cool process gas into the bottle 2. This process gas is cooler than the bottle 2. In this case, the process gas in the bottle 2 begins with a higher density. As it heats up in the bottle, it expands. In so doing, some of it begins to flow out of bottle 2. This prevents ingress of oxygen into the bottle 2.

(42) In the preceding embodiments, UV sterilization and/or curing occurs in an eighth treatment module 7.8 of a treatment section 1 that precedes a filling machine. However, it is also possible to incorporate UV sterilization and/or UV curing in a treatment station of a filling machine. In such embodiments, it is possible to sterilize filling material introduced into a bottle 2 in at least one treatment station. This can be carried out, for example, when bottling mineral waters or table waters.

(43) In the preceding embodiments, pretreatment, printing, and UV sterilization and UV curing are described has taking place in separate processing modules 7.1-7.8. However, it is possible for a single processing module to perform more than one of these tasks.

(44) In other embodiments, particularly in the case of polychrome printing, it is possible to pre-dry a first printing dye before applying a second printing dye and to do so in one or more additional work steps.

(45) In the embodiments described thus far, bottles 2 conveyed through the treatment section 1 stand upright, i.e. with their bottle opening 2.1 pointing up and their bottle axis vertically oriented. Thus, UV treatment in the eighth treatment module 7.8 also takes place in this position. However, embodiments also include those in which the bottles 2 are in a different attitude. These include embodiments in which the bottle is upside-down, so that the bottle opening 2.1 faces downward.

(46) FIG. 6 shows an installation 18 for blow-molding bottles 2 and for the subsequently printing a printed image on the bottles and using UV radiation to sterilize the bottles and cure the printed image. The installation 18 comprises among other things a rotary blow-molding machine 19 having a plurality of blow molds 21. The blow-molding machine 19 includes a rotor 20 that can be driven to rotate about a vertical machine axis. The blow molds 21 are disposed on the side or top of the rotor 20.

(47) During normal operation, the heated preforms are fed to the blow molds 21 over a transport section that includes a preheating section 22. The transport section includes a third conveyor 23 and first and second transport star wheels 24, 25.

(48) A third transport star wheel 26 transfers bottles 2 produced by the blow-molding machine 19 to a treatment section 27. In some embodiments, the treatment section 27 is the same as treatment section 1. The bottles 2 traverse the treatment section 27 to undergo treatment steps already described. After leaving the eighth treatment section 7.8, the bottles 2 are fed via a fourth star wheel 28 and a fourth conveyor 29 to a filling machine.

(49) The transport of bottles 2 from the blow-molding machine 19 to the treatment section 27, through the treatment section or through the various treatment modules or workstations of this treatment section as well as the transport on the fourth star wheel 28 takes place with the bottle upside-down.

(50) A basic difference between the treatment section 27 shown in FIG. 6 and the treatment section 1 shown in FIG. 1 is that in the treatment section 1 shown in FIG. 1, each container carrier 11 is a permanent part of the treatment stations 10, 10a of an individual treatment module 7.1-7.8.

(51) In contrast, in the installation 18 shown in FIG. 6, the same gripper or centering and holding element 30, best seen in FIGS. 7 and 8, is used throughout the process.

(52) In particular, FIG. 7 shows a preform 31 after having been transferred from the third conveyor 23 onto a centering and holding element. FIG. 8 shows the preform after having been transformed into a bottle 2 by blow-molding. As is apparent, the bottle 2 is already held centered. The centering and holding element 30 carries the bottles 2 all the way down the treatment section 27 to the eighth treatment module 7.8, where UV sterilizing of the bottle 2 takes place.

(53) It is only after the bottle 2 has passed through the eighth treatment module 7.8 to the fourth star wheel 28 that bottle 2 is released from centering and holding element 30. Having been sterilized in the eighth treatment module 7.8, the centering and holding element 30 is then returned to the blow-molding machine 19 or to the first star wheel 24 by traversing a return path 32, 33, 34, 35, 36 to pick up a further preform 31.

(54) An advantage of the embodiment shown in FIG. 6 is therefore that the same centering and holding element 30, which has already been sterilized and disinfected, holds the preform 31 and the resulting bottle 2.

(55) Each centering and holding element 30 is configured so as to enable the bottle 2 to swivel or rotated during its treatment, and in particular, during UV sterilizing or UV curing. To achieve this, each centering and holding element 30 either has its own actuator drive or a coupling to enable it to be swiveled or rotated by a drive of a particular treatment station 7.1-7.8.

(56) In some embodiments, the centering and holding elements 30 are configured to hold a bottle 2 in the region of its bottle mouth 2.1, for example by clamping and/or with clamping jaws.

(57) The invention has been described hereinbefore by reference to embodiments. It goes without saying that numerous variations as well as modifications are possible without departing from the inventive concept underlying the invention.