Abstract:
By providing projections extending outwardly from the base of a wet tamping face of a tamping labeler, which projections maintain at least a substantial portion of a label at a stand off from said base, the surface tension between the label and tamping face is reduced. This reduction in surface tension helps ensure that when a label is tamped against a product, it remains there. The tamping face may be provided with a regular, or irregular, pattern of projections, or with a texture that results in the projections.

Description:
BACKGROUND OF INVENTION  
       [0001]     This invention relates to a tamping labeler and to a labeling apparatus having tamping labelers.  
         [0002]     Products to be sold are commonly labelled. In this regard, automatic labelling apparatus may be employed where the products are smaller and processed in large volumes. One approach in this regard is to wipe a label onto each product as its passes a labelling head. This approach, however, is only well suited for labelling products of uniform dimensions. Where products have irregular dimensions, such that the distance between a given product and the labelling head will vary, tamping labellers are typically used. U.S. Pat. No. 5,829,351 to Anderson discloses such a labeller. In Anderson, a turret carries a number of flexible pneumatic bellows about its periphery. The turret has a vacuum plenum and a positive pressure plenum. The turret rotates each bellows, consecutively, to a labelling station. A bellows normally communicates with the vacuum plenum which keeps it in a retracted position; also, due to end perforations in the bellows, the negative pressure holds a label at the end of the bellows. However, when the bellows reaches the labelling station, it is coupled to the positive pressure plenum which causes a one-way valve to block the perforations and causes the bellows to rapidly extend until it tamps a product below. The force of the tamping forms an adhesive bond between the pressure sensitive adhesive of the label and the product. Labels are fed to each bellows from a label cassette with a label web comprising serially arranged labels on a release tape.  
         [0003]     A tamping labeler is suited to the labeling of produce, given the irregular dimensions of produce. However, if the produce is wet, the tamping face of the bellows will also become wet. This can result in the surface tension between the bellows and a label being stronger than the tack adhesion between the produce and the label when the label is tamped against the produce. Should this occur, the label may remain on the bellows. This event may be repeated, such that the bellows may become clogged with a plurality of labels, thereby requiring operator intervention. Even if a bellows does not become clogged, the effectiveness of the labeler is diminished if some labels do not adhere to the produce.  
         [0004]     This invention seeks to address this problem.  
       SUMMARY OF INVENTION  
       [0005]     By providing projections extending outwardly from the base of a wet tamping face of a tamping labeler, which projections maintain at least a substantial portion of a label at a stand off from said base, the surface tension between the label and tamping face is reduced. This reduction in surface tension helps ensure that when a label is tamped against a product, it remains there. The tamping face may be provided with a regular, or irregular, pattern of projections, or with a texture that results in the projections.  
         [0006]     According to the present invention, there is provided a tamping labeler for use in a labeling apparatus, comprising: a tamping face having a base and projections projecting outwardly from said base for maintaining at least a substantial portion of a label at a stand off from said base.  
         [0007]     According to another aspect of the present invention, there is provided a bellows for use in a labeling apparatus, comprising: a tamping face having a base and projections projecting outwardly from said base for maintaining a label at a stand off from said base.  
         [0008]     According to a further aspect of the present invention, there is prvoded a bellows for use in a labeling apparatus, comprising: a tamping face having projections for reducing surface tension between a label held by vacuum to said tamping face and said tamping face when said tamping face is wet.  
         [0009]     According to another aspect of the present invention, there is provided a product labeling apparatus, comprising: an indexing turret carrying a plurality of tamping labelers, each tamping labeler having a tamping face with a base and projections projecting outwardly from said base for maintaining at least a substantial portion of a label at a stand off from said base; a vacuum chamber in fluid communication with each tamping labeler other than at a labeling station; a positive pressure chamber in fluid communication with a tamping labeler at said labeling station; a label supply for supplying a label to a tamping face of a tamping labeler at a label supply station spaced from said labeling station.  
         [0010]     Other aspects and features of the invention will become apparent by reference to the following description in conjunction with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0011]     In the figures which illustrate example embodiments of the invention,  
         [0012]      FIG. 1  is a perspective view of a labeling apparatus made in accordance with this invention,  
         [0013]      FIG. 2  is a plan view of a tamping face of a tamping labeler of the apparatus of  FIG. 1 ,  
         [0014]      FIG. 3  is a fragmentary view of a tamping face of a tamping labeler of the apparatus of  FIG. 1 ,  
         [0015]      FIGS. 4 and 5  are schematic side views of the turret of the labeling apparatus of  FIG. 1 , illustrating operation of the labeling apparatus,  
         [0016]      FIG. 6  is a plan view of an alternate tamping face for a tamping labeler which may be used with the apparatus of  FIG. 1 , and  
         [0017]      FIG. 7  is a plan view of a further tamping face for a tamping labeler which may be used with the apparatus of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0018]     Referencing  FIG. 1 , a labeling apparatus  10  comprises a rotatably mounted turret  40  connected to a stepper motor  44  by a belt drive  42 . A label web  56  comprises a release tape carrying a plurality of labels  60  ( FIG. 4 ) backed with a pressure sensitive adhesive. The label web extends along a U-channel member  68  to a label pick-up station  70 . The label web  56  is advanced by a gear  94  that is intermittently driven by stepper motor  44  through a pin wheel  46 .  
         [0019]     The turret carries a plurality of bellows  160 . Each bellows is fabricated of a flexible material, such as rubber or silicone. The tamping face  162  of each bellows is perforated with holes  164 . A one-way valve  166  ( FIG. 4 ) is disposed inside each bellows proximate holes  164 .  
         [0020]     Turret  40  has a stationary core  110  with a port  112  for connection to a vacuum source (not shown) and a port  114  for connection to a source of positive pressure (not shown). The internal configuration of core  110  is such that each bellows is fluidly coupled to port  112  through most of its rotation about core  110  but is instead fluidly coupled to port  114  when a bellows is at the label applying station  128 .  
         [0021]     Further details of the construction of the labeling apparatus  10  as described so far may be found in WO 02/102669 to Neilsen and Sleiman, published Dec. 27, 2002, the contents of which are incorporated herein by reference.  
         [0022]     Turning to  FIGS. 2 and 3 , a plurality of projections in the nature of domes  170  extend outwardly from a base  172  of the tamping face  162 . The domes are patterned across the face  162  of the bellows  160  and are arranged such that each hole  164  is partially surrounded by domes. By way of example, the domes may have a height of about 5 thousandths of an inch (125 microns) above the base  172  of the tamping face  162  and a diameter of about 50 thousandths of an inch (1.25 mm).  
         [0023]     With reference to  FIG. 4 , a bellows  160  and a label  60  are advanced to the label supply station  70  whereat the label  60  is sucked onto the tamping face  162  of the bellows by a vacuum communicated from port  112  ( FIG. 1 ) to the bellows and through to the tamping face by holes  164  ( FIG. 2 ) through the tamping face. However, the domes  170  maintain the label  60  at a stand off from the base  172  of the tamping face. In this way, all bellows upstream of the label applying station  128  are loaded with labels  60 .  
         [0024]     The turret  40  is indexed (in direction T) past the label applying station  128  at a time when a product, such as item of produce  180  (being conveyed in direction C), is at the label applying station. As the bellows passes through the label applying station, it is coupled to a source of positive pressure through port  114  ( FIG. 1 ), which causes the bellows to extend to tamp the product. This operation is illustrated in  FIG. 5 . During the extension, the one-way valve  166  in the bellows blocks holes  164  so that the label is not blown off the tamping face  162  of the bellows. The pressure sensitive adhesive then adheres the label to the product as the bellows rotates past the label applying station and is retracted due to again being coupled to a vacuum source.  
         [0025]     If the products are wet, the tamping face of the bellows will become wet as-well. In consequence, water will be interposed between fresh labels taken up by the bellows and the tamping face of the bellows. The resulting surface tension must be overcome by the strength of the adhesive bond between the product and the label at the label applying station in order for the label to remain on the product and not on the bellows. The domes  170 , by providing a stand-off between the label and the (wet) base  172  of the tamping face  162  of the bellows, reduce this surface tension so that the labels will remain adhered to products. It will be apparent that, if necessary, the height of the domes could be increased to ensure this result.  
         [0026]     It may be possible to provide a (regular or irregular) pattern of domes such that only a substantial portion of a label was maintained at a stand-off from the base of a tamping face of a bellows. In such instance, the surface tension between the label and bellows would be increased, but provided it were insufficient to overcome the tack adhesion of the label to the product, this would not be problematic.  
         [0027]     With reference to  FIG. 6 , in place of a pattern of domes across the tamping face of a bellows, the face  262  of a bellows  260  may be provided with a pattern of concentric ridges  270 . The spacing of these ridges would be chosen to at least substantially maintain a label at a stand-off from the base  272  of the tamping face  262 .  
         [0028]     With reference to  FIG. 7 , as a further alternative, a circular ridge  370   a  could surround each hole  164  in a bellows  360 . Further, a pattern of linear ridges  370   b  could extend across other portions of the tamping face  362  of the bellows  360 . Again, the spacing of these ridges would be chosen to at least substantially maintain a label at a stand-off from the base of the tamping face  362 .  
         [0029]     As a further alternative, the tamping face may textured such that the texture results in the projections.  
         [0030]     While the tamping labeler described in conjunction with the invention is a bellows, it will be appreciated that the teachings of this invention may be applied to any other type of tamping labeler that is used in a wet environment. For example, this invention has application to a tamping labeler which is in the nature of a spring biased piston, as described in U.S. Pat. No. 5,645,680 to Rietheimer. In Rietheimer, the piston is released by a cam so that it extends under the force of the spring to tamp a product at a label applying station.  
         [0031]     Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.