EP0287018A2 - Labelling device using print checking means - Google Patents

Abstract

The invention relates to a labeling device with a pallet rotor (2) which has pallet surfaces (4). The labeling device also has a label magazine (6) for delivering labels to the pallet rotor and a gripper cylinder (5) which removes the labels removed from the label magazine by the pallet rotor from the pallet rotor. There is also a printing unit (8) which creates a print on the labels between the label magazine and the gripper cylinder. In order to be able to determine that the printing unit is working incorrectly, the invention provides for a reading head (10) to be arranged between the printing unit and the gripper cylinder to check the printing.

Description

The invention relates to a labeling device with a pallet rotor that has pallet surfaces, with a label magazine for feeding labels to the pallet rotor, with a gripper cylinder that removes the labels removed from the pallet rotor from the pallet rotor and with a printing unit that is located between the label magazine and the gripper cylinder is arranged to create an imprint on the labels.

Labeling devices of this type are known. Regarding the general state of the art, reference is made to DE-AS 21 41 306 or DE-PS 20 10 652. Such labeling devices are used to remove labels from a label magazine and to convey them further via a gripper cylinder in such a way that they are attached to the bottles, for example when filling bottles. The centerpiece of such labeling devices is a pallet rotor, which has pallet surfaces that are first moved past a glue roller and are thereby covered with a thin film of glue. These glued pallet surfaces then run past a label magazine, where they remove the foremost label. As the pallet surfaces move on, the labels that are then picked up are guided past a printing unit. The printing unit puts a code or a date, for example the date of filling, on the labels. The labels are transported from the printing unit to a gripper cylinder, which removes the labels from the Pallet areas decreases and then rotated on the transport path of the containers to be labeled, such as bottles.

If errors occur in the printing unit with such devices, for example due to dried ink, the labels are guided past the printing unit without the filling date being printed on. Bottles for which the bottling date is missing, however, may in some cases not be allowed to be sold abroad in accordance with legal regulations. If one takes into account in this context that modern labeling devices of the type described work with up to 21 labeling processes per second, it is clear that even if the system continues to malfunction even briefly, considerable damage occurs, since that with the bottles with defective labels cannot be placed on the market.

The invention has for its object to provide a labeling device of the type mentioned, in which the occurrence of errors in the printing unit can be determined.

This object is achieved in a labeling device of the type mentioned in that a reading head for checking the printing is arranged between the printing unit and the gripper cylinder. With the arrangement of a reading head between the printing unit and the gripper cylinder, the possibility is thus created of being able to check the printing which has been applied to the label by the printing unit immediately beforehand, or to determine whether or not there is any printing at all. The read head can be connected to a device that, for example, shuts down the system if there are several labels without one another Imprint appear. However, the signal from the reading head can also be used, for example if it does not occur continuously, but only occasionally, so that the bottle provided with this label is subsequently ejected. By arranging the read head between the printing unit and the gripper cylinder, the errors in the printing unit can be determined very reliably, because the reading conditions for the reading head itself are best in the area of the pallet carousel. Since the pallet surfaces run with high precision (with deviations of a maximum of 100th of a mm), the assignment of the pallet surfaces to the reading head can be maintained very precisely. The reading head can therefore be adjusted accordingly and then always detects the individual labels at the same point, namely in the area in which the print should be applied. If the inspection were carried out at the bottle table, this would lead to difficult reading conditions due to inaccuracies due to bottle and position tolerances. In addition, if bottles of different shapes are to be labeled, corresponding adjustments to the reading head or the distances between bottles and reading head would be necessary. In addition, if the imprint is to be applied to the label in different positions, different adapted table curves would have to be used. After all, there is a risk that if the bottle breaks, the reading head itself would be damaged by broken glass or liquid.

Any reading head suitable for this purpose can be used as the reading head. So it is possible to use electro-optical read heads or magnetic read heads. Simple diffuse sensors (in the manner of light barriers) can be used as the electro-optical read head. With such simple reflex light scanners it can be determined whether a print is available or Not. However, a more complex solution can also be to use an optical camera as a reading head, which can then not only determine the presence or absence of the print, but is also able to read the print.

As printing units, i.a. Type wheel printers, laser dating, laser printers, inkjet dating, heated stamps can be used.

In principle, the invention can be used for all labeling devices of the type mentioned, the pallet surfaces either being mounted on a rotary cylinder, but it can also be used for labeling devices in which the pallet rotor has upright individual pallet shafts, each of which carries at least one circular-shaped removal pallet and which have a control curve leading the outer surfaces of the individual removal pallets past the reading head.

In particular, the invention can also be used in labeling devices in which the radius of curvature of the removal pallets is smaller than the radius of curvature of the pallet orbit, the control curve then being designed in such a way that it controls the removal pallets in an oscillating movement. In the case of such a labeling device, the control curve is advantageously designed in such a way that the center of curvature of the individual pallets swings in a circular path around the eye of the reading head. This solution is preferably used when the read head allows only small tolerances in its distance from the imprint to be read, ie when the read head is sensitive to depth of field. This type of control of the individual pallets ensures that the part of the print that the eye is reading when the print moves past is always at a constant distance from the eye or the focal point of the read head, so that the read head can be focused on the distance and then enables precise observation. Another embodiment of the control curve can provide that the center of curvature of the individual pallets is stationary on the connecting line between the pallet rotor axis and the eye when the outer surface is pivoted past the reading head. This solution has the advantage that the eye always looks vertically at the respective part of the print that has just moved past, so that regardless of the length of the print it can be observed exactly with reflected light. However, this solution requires a rapid swiveling movement of the individual pallets in the case of the rapid rotary movements of the pallet rotors of this type, which entails correspondingly higher forces.

A currently preferred embodiment therefore provides that the print is applied symmetrically to the central axis of the circular cut-out removal pallet on the labels and that the control curve is designed such that the central axis of the circular cut-out removal pallet when the leading edge of the print runs in before the eye of the reading head in the radial direction of the pallet rotor and remains aligned in the radial direction of the pallet rotor until the trailing edge of the print has passed the eye of the reading head. The individual pallets are held in this solution after taking the aligned position, in which the central axis of the removal pallets and thus also the print center is aligned with the radial direction, and then moved past the reading head in the fixed position. This results in low forces for controlling the Individual pallets, on the other hand, a slight restriction in the width of the imprint is accepted, since the reflected light beam can only be detected by the reading head in a certain angular range.

• Figur 1 zeigt in einer schematisierten Darstellung die Draufsicht auf ein erfindungsgemäßes Etikettiergerät,
• Figur 2 zeigt eine schematische Prinzipskizze einer ersten Ausführungsform, bei der die Entnahmepalette beim Vorbeischwenken am Lesekopf mit ihrem Krümmungsmittelpunkt in einer Kreisbahn um das optische Auge des Lesekopfs herumgeführt wird,
• Figur 3 zeigt ein Ausführungsbeispiel, bei dem der Krümmungsmittelpunkt der Entnahmepaletten beim Vorbeischwenken am Lesekopf auf der Verbindungsachse zwischen Lesekopf und Drehmittelpunkt des Palettenrotors festgehalten wird,
• Figur 4 zeigt ein Ausführungsbeispiel, bei dem die Entnahmepaletten mit ihrer Mittelachse während des Vorbeischwenkens am Lesekopf zum Mittelpunkt des Palettenrotors weisen.

The invention is further explained below with reference to the drawing.

• FIG. 1 shows a schematic representation of the top view of a labeling device according to the invention,
• FIG. 2 shows a schematic basic sketch of a first embodiment, in which the removal pallet is guided with its center of curvature in a circular path around the optical eye of the reading head when pivoting past the reading head,
• FIG. 3 shows an exemplary embodiment in which the center of curvature of the removal pallets is held in place on the connection axis between the reading head and the center of rotation of the pallet rotor when it swings past the reading head.
• FIG. 4 shows an exemplary embodiment in which the removal pallets point with their central axis to the center of the pallet rotor while swiveling past the reading head.

The plan view of the labeling device according to the invention is shown schematically in FIG. 1, the labeling device overall being designated by reference number 1. The core of the labeling device is the Pallet rotor 2, which has removal pallets 4 lying at equal angular intervals from one another, eight removal pallets are shown in the exemplary embodiment shown. The removal pallets sit on pallet shafts 11 which are acted upon by control cams which are not shown in detail in such a way that the pallet surfaces 3 of the removal pallets are pivoted back and forth during a revolution in accordance with a movement path predetermined by a control curve. For further details in this connection, reference can be made, for example, to DE-PS 20 10 652.

The pallet rotor 2, which carries the individual pivoting about the pallet shafts 11 removal pallets 4, rotates in the direction of arrow P₁ at high speed during operation. When the pallet rotor 2 rotates, the individual removal pallets 4 are guided past a glue roller 7 one after the other. The glue roller 7 carries a thin film of glue onto the pallet surfaces 3 which are curved in the form of a circular section. The glued pallet surfaces 3 then run past the front surface of the label magazine 6, where they remove the label lying in front. The label adhering to a pallet surface is then guided past a printing unit 8. The printing unit 8 prints the filling date at a predetermined location on the label. Finally, the label then arrives at the gripper cylinder 5, which pulls the label off the pallet surface and then passes it on to the objects to be labeled, for example bottles, in a known manner. The processes described so far are known.

The invention now provides that between the printing unit 8 and the gripper cylinder 5 a reading head 10 is arranged, which checks the imprint applied by the printing unit 8. Depending on what type of read head is used, the reading head can either determine whether a print has taken place at the examined location or, for example, if the read head 10 consists of a camera, it can also recognize which print has been applied. The arrangement of the reading head 10 in the area of the pallet rotor enables an exact check of the point at which the date imprint should be attached, since the removal pallets in the pallet rotor and thus also the removed labels pass through a highly precise path. The reading head 10 can thus reliably determine whether the printing unit 8 is working correctly. If the reading head 10 determines that no printing has taken place at the location provided for the printing, it can emit a corresponding signal via the signal line 9, which signal can then be used for further control of the system. For example, an optical or acoustic alarm signal can be generated from a signal on signal line 9. It is also possible, if a non-existent imprint is found only once, that the corresponding bottle with the defective label is subsequently automatically excreted or that the entire system is shut down if several labels are found by the read head 10 without imprint. The removal pallets 4 must be guided past the reading head 10 in such a way that it can reliably carry out the overprint check. Depending on the type of reading head used, different paths of movement of the removal pallets past the reading head are conceivable or suitable.

Some of the possible movements are shown in Figures 2 to 4 and are explained in more detail below.

The embodiment shown in Figure 2 explained a case in which a read head 10 is used which is sensitive to depth of field, ie which allows only a small tolerance with regard to the distance to the object to be read for precise work. As in the other exemplary embodiments, the reading head 10 is oriented such that its optical axis points to the center point M _{P of} the pallet rotor (axis of rotation of the pallet rotor). The position of the read head 10 at which the read head detects the signal is referred to in the text as "eye of the read head" and is indicated by 12 in FIG. 2. This can be, for example, the focal point of a taking lens which is arranged in the front of the reading head.

In all of the exemplary embodiments, the radius of curvature r _{u of} the orbit of the pallets is greater than the radius of curvature r _{E of} the individual removal pallets 4. The radius of curvature of the orbit of the pallets is understood to mean the radius r _u shown in FIG. 4, ie the radius of the circumference around the pallets in the middle position. The pivot axis, ie the axis of the pallet waves is shown in Figures 2 through 4 designated by S _E and passes through the web B₂.

So that the reading head 10 in the embodiment shown in FIG. 2 can observe at a constant distance a from its optical eye 12, the center of curvature K _{E of} the pallet surfaces 3 of the removal pallets is guided around a circular path B 1 around the optical eye 12 in this embodiment. In this way it is achieved that the printing on a label adhering to the pallet surface always takes a constant distance a from the reading head as it is passed, that is to say the reading head can then read exactly with the depth of field set accordingly. The The removal pallet is pivoted in the direction of the arrow P₂. A second possibility of moving the removal pallet 4 past the reading head 10 is shown in FIG. This solution offers advantages when working with a reading head working with reflected light and the reading head should be able to recognize the imprint at any position on the label (for example, imprints offset to the right or left of the center axis of the removal pallets 4). In the solution described in FIG. 3, the illuminating light B _L emitted by the reading head 10 is reflected at a constant angle, ie the reflected light beam R _L does not change its point of impact in the reading head 10 during the movement of the removal pallets past the reading head 10. This is achieved by holding the center of curvature K _{E of} the removal pallets for the time that a removal pallet swings past on the connecting axis V _A , which connects the optical eye of the reading head 10 to the center M _{P of} the pallet rotor. The center of curvature migrates radially inwardly toward the center M _P of the pallet rotor in the position that is shown with K 'and _E again before then continues back to the position K _E. The pivoting movement of the removal pallet is in this case in the same direction as in the example shown in Figure 2 and in Figure 3 with the arrow P₃.

In the solution shown in FIG. 3, however, relatively high forces occur since the removal pallet has to perform a very rapid swiveling movement in order to carry out the movement sequence explained.

A currently preferred exemplary embodiment is now explained below with reference to FIG. 4. In this solution it is initially provided that the imprint 13 on the Labels are applied symmetrically to the central axis of the pallet surfaces 3.

Shown in Figure 4 are now three layers L₁, L₂, L₃, which are run through in this order by the individual removal pallets 4. The position L 1 shows the removal pallet moving towards the reading head 10, its central axis M _A pointing away from the center M _{P of} the pallet rotor. The control curve is now designed so that the removal pallet from this position L₁ is first pivoted back in the direction of the arrow P₄ until the central axis M _{A points} to the center M _{P of} the pallet rotor. This position is taken up by the removal pallet at the latest when the leading edge 14 of the print runs into the reading area of the reading head 10. Now the removal pallet is not pivoted forward or backward after reaching this position (position L₂), rather the center of curvature K _{E is} guided on a circular path B₃ around the center point M _{P of} the pallet rotor, ie the removal pallet is moved further together with the rotor, without its central axis M _A performing a pivoting movement with respect to the radial direction of the rotor. This holding of the removal pallets continues until the subsequent edge 15 of the imprint 13 has run out of the reading area of the reading head 10.

The movement sequence described with reference to FIG. 4 has the advantage that the acting forces are very low because the removal pallets are not pivoted. However, the distance with which the reading head 10 reads the imprint changes during the reading process, the reading distance being greatest at the leading and trailing edges and smallest at the center of the imprint. It will then come up with this solution Read head 10 used, the tolerance with respect to the permissible depth of field is greater than or equal to this reading distance change.

The invention is not limited to pallet rotors that work with individual removal pallets whose radii of curvature are smaller than the radii of curvature r _{u of} the pallet orbit. The invention can also be used in the same way for pallet rotors that work with removal pallets in which the radii of curvature are of the same size and can also be used for those pallet rotors that consist of rotating cylinders and have pallet surfaces on the outer circumference. The term “reading head” is also to be understood in the broadest sense, in particular magnetic reading heads are also intended to be included, which can be used when the printer is working with magnetizable ink liquid. In addition to the simpler reflection light reading heads mentioned, cameras can also be used as optical reading heads. It is also conceivable to use the end of an optical light guide as the reading head, which then leads the light to a detection point further away.

Claims (8)

1. Labeling device with a pallet rotor that has pallet surfaces, with a label magazine for feeding labels to the pallet rotor, with a gripper cylinder that removes the labels removed from the pallet rotor from the label magazine from the pallet rotor, and with a printing unit that is between the label magazine and the gripper cylinder Creating an imprint on the labels is arranged
characterized by
that between the printing unit (8) and the gripper cylinder (5) a reading head (10) is arranged to check the imprint. 2. Labeling device according to claim 1,
characterized by
that the reading head (10) is designed as an optical reading head. 3. Labeling device according to claim 1,
characterized by
that the read head (10) is designed as a magnetic read head. 4. Labeling device according to one of the preceding claims,
characterized by
that the pallet rotor (2) has upright, individual pallet shafts (11) which each carry at least one removal pallet (4) and that the removal pallets (4) are controlled so that the pallet surfaces (3) of the individual removal pallets are guided past the reading head (10). 5. Labeling device according to claim 4,
characterized by
that the radius of curvature (r _E ) of the pallet surfaces (3) is smaller than the radius of curvature (r _U ) of the pallet orbit and that the removal pallets are controlled in an oscillating movement by means of a control curve. 6. Labeling device according to claim 5,
characterized by
that the control curve is designed so that the center of curvature (K _E ) of the removal pallets (4) around the eye (12) of the reading head (10) in a circular path (B₁) pivots. 7. Labeling device according to claim 5,
characterized by
that the control curve is designed so that the center of curvature (K _E ) of the removal pallets (4) when pivoting past the pallet surfaces (3) on the reading head (10) stationary on the connecting axis (V _A ) between the center point (M _P ) of the pallet rotor and the Eye (12) of the reading head (10) is. 8. Labeling device according to claim 5,
characterized by
that the imprint (13) is applied symmetrically to the central axis (M _A ) of the circular-section-shaped pallet surfaces (3) on the labels and that the control curve is designed so that the central axis (M _A ) of the removal pallets (4) when the leading edge enters (14) of the imprint (13) in front of the eye of the reading head (10) in the radial direction of the pallet rotor (2) and remains aligned in the radial direction of the pallet rotor until the trailing edge (15) of the imprint (13) on the eye of the Read head (10) has passed.

Images