EP3426495B1 - Device for printing closures of closed containers - Google Patents

Description

The invention relates to a device and a method for printing the closures of closed containers.

State of the art

It is known from the prior art to provide the closures of containers with printed images.

With regard to labeled containers, it's from the DE 10 2006 019 441 A1 known to apply the imprint on the closure based on the random orientation (rotation) of the label attached to the container. The position of the containers, which are transported in a transport star, for example, is known at all times and only their rotational position or the position of the label relative to the print head that is to apply the image to the closure needs to be determined for each container.

Furthermore, from the WO 2015/011663 A1 known to print the closures of containers taking into account the distance between the containers in a transport device. For this purpose, the entry of each container into the corresponding printing station is determined by a light barrier and the printing unit is caused to print on the closure of the container in accordance with this position.

The known methods and devices have in common that they always determine the position of the container as a whole and thus also the position of the closure based on the determination of the position of a label or a part of the container and, depending on this, the pressure device is controlled to close the To print on the container.

Particularly in the case of containers made of glass that are provided with a crown cap, for example, there may be slight deviations in the shape of the actual container from the ideal shape due to the manufacturing process of the glass bottles, so that the containers produced are not rotationally symmetrical. As a result, the printing of the closure can be highly error-prone.

Corresponding problems can also arise with containers made of plastic, in particular PET.

The document JP H04 216989 A discloses a method of printing an image at a specific position on the lid of a beverage can that is conveyed on a belt. For this purpose, the position and orientation of the closure in the lid of the beverage can is recorded with the aid of an image sensor.

task

On the basis of the known prior art, the object to be solved consists in specifying a method and a device for printing closures of closed containers which enable reliable and correct printing of the closure.

solution

This object is achieved by the device for printing closures on closed containers according to claim 1 and a corresponding method according to claim 7. Advantageous further developments of the invention are covered in the subclaims.

The containers can in particular be bottles, here preferably bottles made of glass or plastic, in particular PET. Coated containers can also be printed with the device. The coated containers can also be bottles made from the materials mentioned or from other materials. In particular, containers provided with labels can be printed on.

In principle, all containers that are provided with a detachable closure (crown cap, cork or screw cap or the like) can be printed with the device, ie the closure can be printed. The closures can be metal or plastic closures. Closures that include both metallic components and components made of plastic such as PET are also conceivable. Furthermore, the device can also be used to print on containers that are closed with a closure made of natural, in particular organic materials, or with a closure that encompasses them. Also closures that are additionally provided with a seal, label or a metal foil, as is usual for example with sparkling wine bottles, wine bottles or beer bottles, can be printed. Larger closures, such as screw closures on yoghurt pots, can also be printed.

Since the position of the closure is determined at least transversely to the transport direction for each container to control the printing unit, slight deviations in the shape of the container are compensated and the closure can be correctly printed. Furthermore, since the deviations of each container from the ideal shape can be different from any other container, reliable printing of each container is ensured by determining this position for each individual container.

In one embodiment, the control unit is designed for the purpose of controlling the application of the printing ink, software-based adapting a print image for the closure stored in a memory to the position in order to obtain a print image to be applied and to assign the printing unit to the application of the printing ink based on the print image to be applied Taxes.

Ultimately, this means that the print image to be applied is initially adapted to the position digitally, that is to say based on software, with the aid of the control unit, which can be designed as a computer or the like, for example. This relates in particular to the position at which the print image is applied by the printing unit using printing ink. For this purpose, the stored print image or information pertaining to it, which is transferred to the printing unit and causes the individual nozzles of the printing unit to be controlled, can be changed so that the position at which the printing ink forming the print image is applied from the printing unit is the position of the closure on the container.

With this embodiment, the printing unit can be designed to be stationary, i.e. immovable with respect to the transport path, and yet reliable printing of the print images on the closures can be ensured. Since the software-based modification of the print image can take place more quickly than a displacement of the printing unit relative to the transport path, this embodiment can simultaneously increase the throughput with which the closures of the containers can be printed.

In a further embodiment it is provided that the printing unit is a digital printing unit and comprises a print head with a printing area whose width transversely to the transport direction is greater than the diameter of a closure to be printed and is at most equal to the width of the transport path. So practically any deviations of the container compensated for by their ideal shape and the closures are correctly printed without the need for any means for moving the printing unit.

Furthermore, the printing unit can be designed to be stationary.

It is provided according to the invention that the detection unit comprises optics for taking an image, a lighting device for illuminating at least part of a container transported in the transport path and an optical body assigned to the optics for redirecting beams of the lighting device reflected by the container into the optics .

Information about the container that is necessary for printing the closure of the container can thus also be taken into account.

In a further development of this embodiment, the lighting device can emit light in the visible range and the optical body has a refractive index greater than 1 or consists of reflective material. Characteristics of the container that are visible to the end user can thus be used when determining the print image to be applied to the closure. This can increase the acceptance of the product.

The optical body can be arranged concentrically to the optics and have an opening, the center of which lies on the optical axis of the optics. On the one hand, information relevant to the printing of the closure can be forwarded via the container to the optics and at the same time the position of the actual closure can be made through the opening without any disruptive optical effects.

It is also provided according to the invention that the control unit is designed to rotate a print image stored in a memory for the closure in a software-based manner, depending on the reflected light, in order to generate a print image to be applied depending on the position of a label on the container and the printing unit based on the print image to be applied to control the application of the printing ink. The device can thus not only ensure that the closure is completely provided with a print image, but that this print image is also correctly aligned relative to the label.

In the method according to the invention for printing closures on closed containers, the containers are transported along a transport path and a detection unit determines the position of the closure transversely to the transport direction for each container, as is defined in detail in claim 7.

In one embodiment, the detection unit determines the position optically.

Furthermore, it can be provided that the containers are transported in a random manner, at least with regard to their position transversely to the transport path. Since the position of the closure is determined transversely to the transport path anyway in order to print the closure, devices that ensure the most exact possible movement of the containers transversely to the transport direction can be dispensed with and the throughput of containers may be increased.

It can further be provided that, in order to control the application of the printing ink, a print image for the closure stored in a memory is adapted to the position in a software-based manner in order to obtain a print image to be applied and the printing unit is controlled based on the print image to be applied for the application of the printing ink. The software-based manipulation of the print image can sometimes be faster than changing the position of the printing unit itself with mechanical means, so that even with high throughput or high speed of the containers to be printed, it is possible to individually adjust the output of the printing ink for each container.

According to the invention, it is provided that the closed containers to be printed have a label and a lighting device illuminates the containers at least in an area which has at least part of the label and light reflected from the area is fed through an optical body of an optical system of the detection unit. Thus, not only the position of the closure, but also additional features of the container, in particular the position of the label, can be used to determine the print image to be applied to the closure.

In a further development of this embodiment, the printing unit is controlled by the control unit on the basis of the reflected light supplied to the detection unit for ejecting the printing ink. The print image or design can thus be applied to the container as a function of the label, here in particular the content of the label.

Brief description of the figures

Figure 1

shows a schematic representation of a device for printing closures according to an embodiment,

Figure 2a + b

show schematic representations of the shape of a closed container compared to the ideal shape,

Figure 3

shows a schematic representation of an embodiment of the method for printing the closure,

Figure 4

shows a schematic representation of a device for printing closures according to a further embodiment,

Figure 5

shows a schematic representation of a further embodiment of the method for printing the closure.

Detailed description

Figure 1 shows a device 100 for printing closures 131 of closed containers 130. The device comprises a transport path 101 in which the closed containers 130 are transported along a transport direction (arrow). The transport path thus defines a transport direction for the containers 130. The transport path can be designed as a conveyor belt. Other embodiments, for example a transport of the containers on standing plates, is also conceivable. The transport path does not have to be linear, but can also be provided as part of a machine designed as a rotary machine with several container receptacles.

The device 100 can be part of a container treatment system for treating containers. In addition to the device 100, the container treatment system can have further container treatment machines, in particular a filler, a closer and a labeling machine include. These container treatment machines can all be arranged upstream of the device 100. However, one or more can also be provided downstream of the device. If the device is integrated into such a container treatment system, it is preferred if not only the closer but also a labeling machine or printing machine for labeling / printing the container are arranged upstream of the device.

A detection unit 102 is arranged in the area of the transport path 101. This detection unit is arranged in such a way that it can determine at least the position of the closure 131 of each container 130 transversely to the transport direction. The detection unit 102 can for example be designed as a 2D, 3D or line camera and be arranged above the transport path 101, the optics of the camera pointing in the direction of the transport path. The distance between the detection unit and the transport path is selected so that closed containers 130 can be transported in the transport path 101 through under the camera. The detection unit does not have to be designed as a camera, but is in any case designed in such a way that it can determine the position of the closure transversely to the direction of transport. This means that the detection unit can determine how the closure is positioned on the container relative to a reference, for example the center of the transport path 101.

In the transport direction after the detection unit 102, a printing unit 103 is arranged which can print on the closure 131 of a container 130 transported in the transport path 101. For this purpose, the printing unit 103 can be designed, for example, as a digital print head, in particular as an inkjet print head, and can apply printing ink to the closure 131. All digitally controllable, contactless printing methods, in particular drop-on-demand methods and corresponding print heads, are preferred.

The printing ink is applied in such a way that a predetermined print image is created on the closure 131. It goes without saying that further printing units can be provided one after the other in the transport direction. In particular, each printing unit can be designed to output printing ink with a different color, so that a multicolored image can be generated by using a plurality of printing units.

A control unit 105 is assigned to the detection unit 102 and the printing unit 103. This control unit receives, on the one hand, a signal from the detection unit 102, which is indicative of the position of a closure 131 transversely and also along or parallel to the transport direction. This signal can be indicative of the distance between the center of the closure and the center of the transport path 101, for example. This signal is used by the control unit 105, in order to control the printing unit 103 in such a way that it ejects printing ink as a function of the signal, so that the printing ink is applied to the closure 131 and a print image is generated on the closure.

It is particularly preferred if the printing unit 103 is designed as a digital printing unit for this purpose and is furthermore arranged in a stationary manner in relation to the transport path 101. So that closures 131 can be provided with a print image, the position of which is different with respect to the center of the transport path 101 or any other reference, the printing unit can comprise a print head with a print area that extends transversely to the transport direction in an area that is larger is than the diameter of the clasp. It is particularly preferred if the printing area transversely to the transport direction is just as wide as the transport path 101. Not only can deviations in the shape of the container and thus the position of the closure from the ideal shape be taken into account, but also in the case of disordered transport of the containers in the transport path , also deviations in the position of the containers themselves.

Furthermore, a further detection unit 104 can be arranged along the transport path 101, which determines the position of the containers in the transport direction. This can also be used advantageously in combination with the detection unit 102 in order to determine the position of the closure more precisely not only transversely to the transport direction but also in the transport direction, in particular in relation to the container. The further detection unit 104 can be designed, for example, as a light barrier that detects the passage of a specific point on the transport path through a container. This further detection unit 104 can also be connected to the control unit 105 and transmit to it a signal indicative of the position of the containers along the transport route. In addition to the signal of the detection unit 102 used to control the printing unit 103, the control unit 105 can also use this signal.

In order to improve the quality of the printed image applied to the closure, it can be provided that a treatment unit for treating the container or at least the closure is arranged upstream of the device or at least upstream of the printing unit 103. This treatment unit can be designed as a pyrolysis device, plasma coating device or corona treatment device. The closures can also be treated with such a treatment unit before the closures are applied to the container, so that the treatment unit can be provided in a closure device which is arranged upstream of the device 100. With the treatment, the surface of the Closure is preferably treated so that it can be wetted better with the printing ink than the untreated surface of the closure. The adhesion of the printing ink to the surface should also be improved by treating the surface compared to the untreated surface. This can be achieved, for example, by treating the closure to reduce or increase the surface tension of the surface to be printed on to a certain value.

If the device 100 is integrated into a container treatment system that includes a labeling machine, the treatment unit is preferably arranged downstream of the labeling machine and upstream of the device 100.

Furthermore, a drying or aftertreatment device, which dries or treats the applied printing ink on the closure, can be arranged downstream of the device 100 or at least downstream of the printing unit 103. For this purpose, a UV tunnel or infrared tunnel with one or more corresponding radiation sources can be provided. Alternatively, individual of these radiation sources can also be arranged after the printing unit 103 in the area of the transport path.

The transport of the containers in the treatment unit does not have to take place in one lane. A transport device that guides the containers along or through the treatment unit can also be designed as a mass transporter.

Figures 2a and 2 B show in an exaggerated manner the deviation of an actual, to be printed and sealed container 130 compared to an ideal shape 230. In FIG Figure 2a a side view of a corresponding container 130 in the transport path 101 is shown for this purpose. In the ideal case, which cannot always be achieved during production, the container 230 is a body that is essentially rotationally symmetrical about an axis L. Embodiments of the containers as bottles, in particular glass bottles or PET bottles, should be considered here, for example. It should be mentioned that non-rotationally symmetrical containers can also have a shape that deviates from an imaginary ideal shape. For the following discussion, however, a container is assumed whose ideal shape is rotationally symmetrical with respect to the L axis. All the methods and devices that are described here can, however, also be applied to containers whose associated ideal shape is not rotationally symmetrical.

In addition, the process opens up the possibility of conveying the containers freely on the belt without the need for guide elements such as railings to guide the containers with millimeter precision must be or pairs of belts must take over the centering of the container to the print head. This has the advantage that changeover work when changing production from one container shape to another can be largely avoided.

With the ideal shape of the container 230, the axis L and the center of the closure 231 coincide. With ideal transport of the container 230 in the transport path 103, the center line of the transport path with the axis L also forms a plane which is perpendicular to the transport path. This ideal case relates to transport routes whose transport surface on which the containers are positioned during transport is exactly horizontal. In the case of the horizontally inclined transport surfaces, however, the above statements can be directly applied to the ideal transport of the containers provided. The angle that the axis L forms with the horizontal or the horizontal should be mentioned in particular. With ideal transport of ideal containers along a sloping transport path, the axis L of each container always encloses the same angle with the horizontal or vertical.

However, since the materials are exposed to stresses during the manufacture of the containers, especially in the case of glass bottles and PET bottles (uneven cooling, deformation, solidification, crystallization, filling, sealing, manufacturing tolerances and the like), not every container will have the ideal shape 230, so that During transport along the transport route, the closure 131 of the container 130 usually has a position which deviates from the ideal position 231. A common manufacturing tolerance of a 0.71 bottle made of PET or glass is usually around 1.8mm in diameter. In the case of a closure with a diameter of 30mm, this results in a corresponding requirement with regard to accuracy in the x and y directions. If the containers are also transported with play within the transport path 103, the entire position of the container can continue to deviate from the ideal position 230.

The deviation of the actual position of the shutter 131 compared to the ideal position 231 is in FIG Figure 2b shown. The position of the closure 131 of the container 130 in the transport path 101 is shown here with reference to the detection unit 102, which determines the position of the closure 131. It is in the Figure 2b a top view of the transport path and the container 130 located therein through the detection unit 102. It can be assumed to a good approximation that the position of the closure or the container on the conveyor belt 131 does not differ between the detection unit 102 and the printing unit 103 changed so that the detection unit 102 determined position of the shutter 131 can be used to control the printing unit. The print head is preferably located in the immediate vicinity of the detection unit on the same section of tape, but not further than 1 m away. It can be advantageous if the belt section between the detection unit and the printing unit runs in a straight line and the containers do not experience any acceleration, at least in this belt section. This prevents the containers from moving from the detection unit to the printing unit, ie from slipping on the conveyor belt

To do this shows Figure 3 a corresponding procedure. The case s = 0 should first be discussed. In this case, the position of the shutter 131 corresponds to that with reference to FIG Figures 2a and 2 B described ideal position of the shutter. For this ideal position, the control unit can contain a print image 250 in a memory assigned to it. This print image, which can be stored in a file, for example, is assigned further information that enables the printing unit to be activated for the purpose of applying the printing ink. This additional information relates in particular to position details of the print image to be applied to the closure in relation to the printing unit 103. This also includes information that enables the individual nozzles of a printing unit, for example designed as a digital printing unit, to be controlled. Given the ideal position of the shutter (s = 0), the print image 250 stored in the memory can be used by the control unit together with the additional information in order to control the printing unit 103. The stored print image corresponds here to the print image 260 to be applied to the containers with regard to its intended position.

In the case s ≠ 0, which usually occurs during production, the application of the printed image 250 to be applied would be in accordance with Fig. 2a mean a qualitatively poorer print image that is incorrectly positioned with respect to the center of the closure, for example, or that would not be completely printed on the container. On the basis of the signal output by the detection unit, which is indicative of the actual position of the closure 131 transversely to the transport direction and thus of the deviation s from the ideal position, the control unit can modify the print image 250 stored in the memory and a print image to be applied to the closure 131 251 generate. This is preferably done completely software-based. This means that the original print image 250 is only digitally modified using, for example, a computer or a processor or similar devices. In particular, the information which is also assigned to the print image and which enables the printing unit and, in particular, individual printing nozzles to be controlled, is changed based on the signal received from the detection unit. The thus obtained, The print image to be applied is then used to control the printing unit 103, which applies the print image 261 to the closure of the container instead of the print image 260. If a 3-D camera is used, z information can also be transmitted to the print head in order to compensate for container height differences such as those that occur when processing reusable PET. The use of the depth information is particularly advantageous if the closures to be printed have indentations or elevations, for example a relief.

Instead of mechanically changing the position of the printing unit or a printing head, the control of the printing unit is changed digitally in such a way that the print image or printing ink is applied as a function of the actual position of the closure 131. This can be done much faster than a mechanical change in position of the printing unit, so that the throughput of containers can be very high.

The change in the position of the print image that is output by the printing unit 103 and is ultimately defined by the print image to be applied or the data file 251 representative of this for controlling the printing unit can also be based on the position of the closure in the direction of the transport path take place on a corresponding signal of the detection unit 102, but also of the detection unit 104. For this purpose, a two-dimensional or three-dimensional coordinate system can be used within the control unit 105, in particular a Cartesian coordinate system. Transformations of the print image for generating / maintaining the print image to be applied can then take place in this coordinate system by coordinate transformation of the image points of the print image. The same coordinate system or a coordinate system linked to the coordinate system by a known transformation can be used to control the printing unit or the printing nozzles of this printing unit.

The x, y, z rotational positions or contour information can be transmitted via a rotary encoder and a controlled or tracked transfer of coordinates to the printing module.

The embodiment as described with reference to Figure 3 has been described, allows the print image or printing ink applied by the printing unit to be adapted to translational changes in the position of the print image. This means that the actual position of the shutter 131 results from a shift in the ideal position of the shutter, as shown in FIG Figures 2a and 2 B has been described.

In some applications, however, it may be necessary to take into account not only this displacement, but also rotations of the container with respect to its ideal alignment along the transport route.

This embodiment is described with reference to Figures 4 and 5 described. In the Figure 4 a container 130 is shown in the transport path 101, which in addition to the closure 131 also includes a label 431. This label may be applied to at least a portion of the outer surface of the container 130. With the in the Figures 4 and 5 described embodiment, not only a print image corresponding to the position of the closure relative to the ideal position is applied, but at the same time a print image that is correctly oriented with respect to the label. For this purpose, at least one lighting device 421 and / or 422 is also provided in the device, which can illuminate the container 130 at least in an area that includes the label 431. For this purpose, the lighting device can, for example, emit light in the visible range (441 and 442). This light is reflected from the surface of the container and from the label, in the dashed directions 451 and 452, respectively, shown by the arrow.

In this embodiment, it is further provided that the detection unit 402, which includes appropriate optics for picking up light and can be designed as a camera, for example, is assigned an optical body 423. The optical body 423 is arranged in such a way that at least part of the light 451 and 452 reflected by the container passes through it or penetrates into it. Furthermore, the optical body is designed in such a way that it redirects this light by reflection and / or refraction of the light 451 or 452 in such a way that it strikes the optics of the detection unit and can be detected there. The position of the label on the container and thus its relative orientation in the transport path 101 can then be determined on the basis of the detected, reflected light 451 or 452. For example, this relative orientation can be determined with reference to a reference variable. The reference variable can be selected so that the center of the label on an ideally positioned container lies in a plane running perpendicular to the transport path and passing through the center line of the transport path. Furthermore, this reference variable can correspond to the case in which the label points in the transport direction of the container.

In order to avoid influencing the determination of the position of the shutter 131 by optical effects of the optical body 423, the optical body can include an opening or recess 424, the center or longitudinal axis of which lies on the optical axis of the optics of the detection unit. The opening can be dimensioned so that all possible Occurring displacements of the closure 131 transversely to the transport direction can be detected by the optics through the opening. For example, the opening can have a diameter of 4 cm. Other diameters are also conceivable here. The edge of the optical body which delimits the recess 424 can be used in an advantageous manner, for example, to support the reflection or refraction of the light reflected by the container into the optics.

While this embodiment has been described with reference to a label applied to the container, other applications are also conceivable. In principle, this embodiment is suitable for printing the closure with regard to any orientation predetermined by a feature of the container and / or closure. For example, the print image can also be applied to the closure as a function of a geometric feature of the container or the closure and its orientation in relation to a reference orientation or ideal orientation. Geometric features include, for example, certain shapes such as edges of the closure or bulges or notches in the container at a certain point on the container. Basically, these features are symmetry breaking features that define a certain preferred direction.

While in the above and the following description reference is made to a specific orientation given by the label, all embodiments can also be applied to other features of the container or the closure if these features require a specific orientation of the printed image on the closure.

Analogous to the in Figure 3 In this embodiment, the printing unit can also be controlled as a function of the position and orientation of the container or closure determined by the detection unit.

This is schematically shown in Figure 5 shown. First, the case s = 0 and α = 0 is discussed. In this case, α corresponds to the angle by which the label is rotated with respect to any fixed reference. This is like turning the container with the label to this reference. In the in Figure 5 The illustrated embodiment, the center line of the transport route is used as a reference. A match between the reference and the orientation of the container means here that the center of the label lies on the center line of the transport path and the label points in the direction of transport of the container. If, on the other hand, an imaginary line of the axis of rotation of the container closes through the center of the label, this line running parallel to the plane in which the containers are transported, a line different from zero Angle α with the center line, the alignment of the container does not match the reference. Any other reference variable can also serve as a reference.

In the event that the container 130 with the label is aligned or rotated exactly as provided by the ideal position, the control unit can use the print image 550 stored in the memory as the print image 560 to be applied. The information stored in addition to the print image with regard to the control of the printing unit 103, in particular the print nozzles, can be used to ultimately output printing ink in such a way that the print image 560 at the in Figure 5 position shown on the closure 131 is applied.

In the event that a = 0 and s ≠ 0, ie the container is not rotated with respect to the reference but the closure is displaced, the method according to FIG Figure 3 can be used to take the position of the shutter into account when controlling the printing unit.

In the general case that α 0 and s ≠ 0, the print image stored in the memory of the control unit is on the one hand analogous to Figure 3 modified to control the printing unit depending on the displacement of the shutter 131 with respect to the reference position. On the other hand, the print image stored in the memory is modified as a function of the angle α by which the label 431 is rotated with respect to the reference position. For this purpose, the print image is rotated digitally or using software so that the alignment of the print image corresponds to the alignment of the label on the container to be printed. If the angle α is, for example, 25 °, the print image stored in the memory is also rotated by 25 ° in the same direction. The two transformations of the print image stored in the memory can be carried out simultaneously or one after the other on the print image in order to determine the print image to be applied. In particular, the known laws for affine transformation can be applied in two dimensions.

In general, for the software-based adaptation of the print image in the memory with the closure displaced with respect to the ideal position and simultaneous rotation of the container, any point is located x of the print image to be applied from the coordinates of the original point p according to
x = A p + s
where A is the rotation matrix in two-dimensional Cartesian space (using the angle of rotation a by which the container is rotated with respect to the reference) and s is the displacement vector corresponding to the displacement s. It is assumed, without loss of generality, that the center point of the coordinate system used here is in The center of the print image lies (central affine image). If only the displacement of the closure transverse to the transport direction is taken into account for the determination of the print image to be printed, then the component of the vector parallel to the transport direction of the container is used s always 0.

This calculation can be carried out for each original image point of the print image stored in the memory and thus the print image to be applied can be determined for a closure or container that is arbitrarily shifted and rotated with respect to the ideal position. This transformation can be carried out even more effectively, for example, by a processor of the control unit that is optimized for parallel computing (for example a graphics processor). However, the processors in control units that are generally used for control can also be used for this purpose, since they are ultimately floating point numbers.

In the Fig. 4 The embodiment described is also suitable for printing closures of containers that have already been supplied to a distribution center in a container treatment plant. In such a distribution center there can be many, even different, containers. Since the device according to the in Fig. 4 described embodiment can ultimately recognize not only the position but also the content of the label, the printing unit can not only be controlled in such a way that the position and orientation of the print image to be applied to the closure is adapted to the position of the closure, but also the print image itself software-based selection based on the information received about the orientation, content and size of the label.

Claims (11)

1. Device (100) for printing closures (131) of closed containers (130), comprising a transport section (101) for transporting the containers, wherein a detection unit (102) and a printing unit (103) for printing the closure of a container are arranged one behind the other in transport direction, wherein the detection unit can individually determine the position of the closure transversely with respect to the transport direction for each container and can transmit a signal indicative of the position to a control unit (105) which is assigned to the detection unit and the printing unit, wherein the control unit is configured to control the printing unit to apply printing ink to the closure in order to print the closure, depending on the position, wherein the detection unit (402) comprises an optical unit for taking an image, an illumination device (421, 422) for illuminating at least a part of a container (130) transported in the transport section and an optical body (423) assigned to the optical unit for diverting rays (451, 452) of the illumination device reflected from the container into the optical unit, characterized in that the control unit is configured to rotate a print image stored in a memory for the closure on the basis of software, depending on the reflected light, to produce a print image (551) to be applied depending on the position of a label on the container and to control the printing unit (103) on the basis of the print image to be applied for the ejection of the printing ink.
2. Device (100) according to claim 1, wherein the control unit (105) for controlling the ejection of the printing ink is configured to adapt a print image stored in a memory for the closure on the basis of software to the position to obtain a print image (251) to be applied and to control the printing unit (103) based on the print image to be applied for the ejection of the printing ink.
3. Device (100) according to claim 1 or 2, wherein the printing unit (103) is a digital printing unit and comprises a printing area whose width transverse to the transport direction is greater than the diameter of a closure (131) to be printed and at most equal to the width of the transport section (101).
4. Device (100) according to any one of claims 1 to 3, wherein the printing unit (103) is arranged in a stationary manner.
5. Device (100) according to claim 1 to 4, wherein the illumination device (421, 422) can emit light in the visible range and the optical body (423) has a refractive index greater than 1 or consists of reflective material.
6. Device (100) according to any one of claims 1 to 5, wherein the optical body (423) is arranged concentrically to the optical unit and comprises an aperture (424) whose center point lies on the optical axis of the optical unit.
7. Method for printing closures (131) of closed containers (130), wherein the containers are transported along a transport section (101) and a detection unit (102) determines the position of the closure transversely with respect to the transport direction for each container and a printing unit (103) applies printing ink for producing a print image to the closure, wherein the ejection of the printing ink is controlled by a control unit (105) on the basis of a signal which is output by the detection unit (102) and is indicative of the position of the closure transversely with respect to the transport direction, wherein the closed containers (130) to be printed comprise a label (431) and an illumination device (421, 422) illuminates the containers at least in an area which comprises at least a part of the label and light reflected from the area is supplied through an optical body (424) to an optical unit of the detection unit (102), characterized in that a print image for the closure (131) which is stored in a memory is rotated software-based, depending on the reflected light, to produce a print image (551) to be applied depending on the position of the label (431) on the container, and the printing unit (103) is controlled based on the print image to be applied for the ejection of the printing ink.
8. Method according to claim 7, wherein the position is optically determined by the detection unit (102).
9. Method according to claim 7 or 8, wherein the containers are transported in a disordered manner at least with respect to their position transversely to the transport section.
10. Method according to any one of claims 7 to 9, wherein for the control of the ejection of the printing ink a print image stored in a memory for the closure is adapted on the basis of software to the position to obtain a print image (251) to be applied and the printing unit (103) is controlled on the basis of the print image to be applied for the ejection of the printing ink.
11. Method according to claim 7 to 10, wherein the detection unit (103) is controlled by the control unit (105) on the basis of the reflected light supplied to the detection unit (102) for the ejection of the printing ink.

Images