Device for printing containers and method for inspecting containers in a printing device

Abstract

An apparatus for printing on containers includes a transporter transports containers that are to be printed upon along a transport track to a container inlet of a printing station. An inspector inspects containers upstream of where transfer of the containers to the container inlet occurs. The inspector includes a light and camera that face each other. The light illuminates a first side of a container and the camera views an opposed second side thereof. Illumination of the first side scatters light from the container, thereby rendering its material distribution visible to the camera. The camera collects data that represents this distribution as different brightness values or gray scale values. A controller uses this data to identify a defective container, the defective container having brightness values or gray scale values that differ from standard values thereof.

Claims

1-20. (canceled)

21. An apparatus for printing on containers, said apparatus comprising a transporter, a controller, and an inspector, wherein said inspector comprises a camera and a light, wherein said transporter transports containers that are to be printed upon along a transport track to a container inlet of a printing station, wherein said inspector is allocated to said transporter and disposed to inspect containers upstream of where transfer of said containers to said container inlet occurs, wherein said light and said camera are disposed along an axis of said inspector facing each other such that said light illuminates a first side of a container and said camera is disposed to view a second side of said container that is opposite said first side, wherein illumination of said first side causes light to be scattered from said container, thereby rendering a characteristic material distribution of said container to be visible to said camera and enabling said camera to collect data that represents said characteristic material distribution using different brightness values or gray scale values, and wherein said controller, which receives data from said inspector, is configured to identify a defective container, said defective container having brightness values or gray scale values that differ from standard values thereof.

22. The apparatus of claim 21, further comprising an upstream removal unit that is disposed upstream of said container inlet, wherein said defective container is defective prior to entering said printing station and wherein, in response to instructions from said controller, said first removal unit removes said defective container, thereby preventing said defective container from entering said printing station.

23. The apparatus of claim 21, further comprising a downstream removal unit that is disposed downstream of a container outlet of said printing station, wherein said defective container is discovered to be defective after said container has passed through said printing station, wherein, in response to instructions from said controller, said downstream removal unit removes said defective container from a container flow downstream of said printing station.

24. The apparatus of claim 21, wherein said defective container is found to be defective after having been printed upon in said printing station, wherein inspector is configured to identify a device that was used for printing upon said defective container and to render said device inactive, wherein said device is selected from the group consisting of a printing unit and a printing head.

25. The apparatus of claim 21, further comprising a removal unit disposed to intercept a defective container, wherein said removal unit is a lock-type unit.

26. The apparatus of claim 21, wherein said controller further comprises a memory in which is stored a characteristic material distribution of a base of said container as captured by said camera.

27. The apparatus of claim 21, wherein said transporter comprises a container receiver that secures said camera.

28. The apparatus of claim 21, wherein said transporter comprises a container receiver that is configured to hold containers at a location selected from the group consisting of a container neck, a neck ring, and a flange of said container.

29. The apparatus of claim 21, wherein said transporter is configured to transport containers along a linear path.

30. The apparatus of claim 21, wherein said transporter is configured to transport containers along a circular path.

31. A method comprising identifying a defective plastic container that is being transported by a transporter toward an inlet of a printing machine, said method comprising, causing said container to enter an inspector that is allocated to said transporter and disposed to inspect containers upstream of said inlet, wherein said inspector comprises a light and camera that are disposed along an axis of said inspector facing each other such that said light illuminates a first side of a container being inspected and said camera is disposed to view a second side of said container being inspected, said second side being opposite said first side, using said light to illuminate said first side, thereby causing light scattered from said container to render visible to said camera a characteristic material distribution of said container, using said camera, collecting data that represents said characteristic material distribution, said data comprising brightness values or gray scale values, causing a controller connected to said inspector to receive said data, and causing said controller to identify a defective container, said defective container having brightness values or gray scale values that differ from standard values thereof.

32. The method of claim 31, further comprising causing said camera to collect light scattered from said container's base.

33. The method of claim 31, further comprising storing said characteristic material distribution of said container base as captured by said camera in a memory connected to said controller.

34. The method of claim 31, further comprising storing images of said container base in a memory connected to said controller.

35. The method of claim 31, further comprising defining said standard values using stored images of container bases.

36. The method of claim 31, further comprising using a removal unit to remove said defective container, thereby preventing said defective container from entering said printing station.

37. The method of claim 31, further comprising identifying a container as defective after said container has passed through said printing station and removing said container from a container flow downstream of said printing station.

38. The method of claim 31, further comprising identifying a container as defective after said container has passed through said printing station, identifying a device used to print on said container, and disabling said device, wherein said device is selected from the group consisting of a printing unit and a print head.

39. The method of claim 31, further comprising suspending said container while transporting said container along a transport track towards said printing station.

40. The method of claim 31, further comprising obtaining reference values of a position and symmetry of a base seam of said container and using said reference values to identify said defective container.

Description

DESCRIPTION OF THE DRAWINGS

[0032] The invention is explained in greater detail hereinafter on the basis of the figures and relating to exemplary embodiments. The figures show:

[0033] FIG. 1 shows an apparatus for printing on containers.

[0034] FIG. 2 shows details of an inspector associated with the apparatus of FIG. 1;

[0035] FIG. 3 is a perspective view of an inspector associated with the apparatus shown in FIGS. 1 and 2;

[0036] FIGS. 4-6 show embodiments having one or more base bodies with cut-out openings for accommodating one or more components.

[0037] Identical reference numbers are used in the Figures for elements of the invention which are the same or have the same effect. Moreover, for easier overview, only reference numbers are represented in the individual Figures which are required for the description of the respective Figure.

DETAILED DESCRIPTION

[0038] FIG. 1 shows a view from above onto a device 1 for the printing on containers 2, such as bottles, and in particular, PET bottles.

[0039] The device 1 includes first and second transporters 3, 5 that are upstream and downstream, respectively, of at least one printing station 8 having a container inlet 6 and a container outlet 7. The first transporter 3 transports the containers 2 along a transport track T to the container inlet 6 of the printing station 8. The second transporter 5 receives containers 2 from the container outlet 7.

[0040] The printing station 8 includes at least one printing unit 8.1 having at least one printing head 8.2. Each printing unit 8.1 is an ink-jet printer that prints directly on a container 2.

[0041] The first transporter 3 includes an inspector 10 disposed upstream of where containers 2 are transferred into the container inlet 6, details of which are shown in FIG. 2.

[0042] Referring now to FIG. 2, the inspector 10 comprises a light 12 and a camera 14. The light shines light LR along an axis A and illuminates a first side S1 of a container 2 that is to be inspected. The camera 14 lies opposite the light 12 facing a second side S2 of the container 2. In the illustrated embodiment, the first side S1 is on the container's base 2.3 and the second side S1 is at the container's mouth 2.4. In this configuration, the camera 14 captures brightness and gray-scale values that are indicative of a characteristic material distribution.

[0043] Also shown in FIG. 2 is a container receiver 4 of the first transporter 3. The container receiver 4 secures both the camera 4 and the container 2. In a preferred embodiment, the container receiver 4 secures the container at its container neck 2.1 or at a flange or neck ring 2.2. This results in the containers 2 being suspended as they are transporter.

[0044] Referring back to FIG. 1, the inspector 10 connects to a controller 20 that both controls the inspector 10 and evaluates data provided by the inspector 10. In doing so, the controller 20 determines whether the gray-scale or brightness values deviate from a standard. In some embodiments, the controller 20 is remote from the inspector 10 and connects to it using either a wired or wireless communication link. In other embodiments, the controller 20 is integral with the inspector 10.

[0045] The controller 20 includes an associated memory SE for storing a characteristic material distribution of the container base 2.3. This can be derived by saved images B of the container base 2.3. The standard value is likewise stored in the memory SE and serves as a reference image.

[0046] The device 1 further includes first and second removal units 16, 17.

[0047] The first removal unit 16, which lies just upstream of the container inlet 6, removes containers 2 that have failed inspection by the inspector 10. Such containers 2 have gray scale and brightness values that deviate excessively from the standard value.

[0048] The second removal unit 17, which lies downstream of the printing station 8, also removes containers 2 that have gray scale and brightness values that deviate excessively from the standard value. In addition, the printing unit 8.1 and/or printing heads 8.2 responsible for printing on that container 2 is switched off.

[0049] As a result of the foregoing configuration, it is possible for containers 2 to be checked for correctness of shape and/or dimensions rapidly and easily before the actual printing thereon. As a result, container that have been deformed, for example by not being correctly stretched, and containers that have otherwise been damaged, are barred from entering the printing station 8 and printing units 8.1 that have proven troublesome are barred from printing on containers 2.

[0050] The camera's field-of-view encompasses the mouth 2.4 and is thus able to inspect the distribution of gray scale or brightness values over the entire container base 2.3. A white container base 2.3 on an image B is a telltale sign of deformation or damage. Such a container 2 is therefore excluded from the printing station 8. This avoids damage or destruction of various components of the printing station 8. This results in lower maintenance cost.

[0051] FIG. 3 shows a perspective view of the inspector 10 allocated to the first transporter 3, according to FIGS. 1 and 2. As is apparent, the inspector 10 is secured to a carrying-and-holding device 9 having one of many possible forms. As a result, it is a simple matter to retrofit existing printing stations 8 to include an inspector 10. The embodiment shown in FIG. 4 shows a modular base 50 having cut-out openings 52. In this embodiment, the various components, namely the first and second transporters 3, 5 and the printing station 8 are secured at corresponding cut-out openings 52. In some embodiments, the container inlet 16 and the container outlet 17 are likewise secured to corresponding cut-out openings 52.

[0052] FIG. 5 shows an embodiment similar to that shown in FIG. 4 but with two modular base bodies 50.

[0053] FIG. 6 shows a further embodiment in which only the first transporter 3, the printing station 8, and the second transporter 5 are arranged in other cut-out openings 52 of the modular base body 50.

[0054] As a result, no limits are set for the invention as far as the arrangement of the individual components 1 on one or more modular base bodies 50 is concerned.

[0055] The invention has been described heretofore on the basis of exemplary embodiments. It is understood that a large number of modifications or derivations are possible without thereby departing from the scope of protection of the invention as defined by the claims.