Label adhesive application assembly

Information

  • Patent Grant
  • 6235345
  • Patent Number
    6,235,345
  • Date Filed
    Thursday, April 29, 1999
    25 years ago
  • Date Issued
    Tuesday, May 22, 2001
    23 years ago
Abstract
An improved adhesive application assembly (70) for a labeling machine (2) includes an adhesive sprayer (76) which directs heated adhesive (88) towards labels (60) passing the adhesive application station (70). A moving heated adhesive shield (80) includes one or more windows (84), through which the adhesive is sprayed, surrounded by a heated overspray-intercepting surface (90). The intercepted adhesive is collected for reuse.
Description




BACKGROUND OF THE INVENTION




Labeling machines are used to apply labels to all types of containers, both cylindrical containers and non-cylindrical containers, such as regular and irregular shaped polygons. One type of conventional label is a self-stick label, also called a pressure-sensitive label, which is carried by a backing strip. Self-stick labels are expensive and create a large amount of waste. Self-stick labels typically used with high-density polyethylene (HDPE) containers, such as milk jugs and juice bottles, are commonly a paper/propylene/adhesive laminate. When such self-stick labels are applied to conventional HDPE containers, the label must be cut out, often by hand, before the container can be recycled. Therefore, a tremendous amount of waste is created by the use of conventional laminated, self-stick labels on the estimated eight to ten billion one-gallon and half-gallon HDPE containers used in the U.S. annually.




Another type of commonly used labels is cut from continuous label material wound onto a roll. Labels made from continuous label material are more economical than self-stick labels and are often made from thin, stretchable film. To reduce the cost, the film keeps being made thinner. This stretchiness can make it difficult to ensure that the labels are properly cut.




Conventional labeling machines remove the continuous label material from the roll and feed the label material to a cutting system. The continuous label material is then cut into labels which are transferred face down onto the circumferential surface of a vacuum drum where they are held in place by vacuum. As the drum rotates the labels pass a glue roller which applies adhesive to the back (outer) surface of the label, typically at its leading and trailing edges. The label, with the adhesive applied thereto, is released from the drum as it comes into contact with and is applied to a container.




SUMMARY OF THE INVENTION




The present invention provides an efficient and cost-effective method for applying adhesive to labels.




A label adhesive application assembly includes an adhesive sprayer which directs heated adhesive towards labels passing along the label path. A movable heated adhesive shield is used to control the spray of the heated adhesive to the proper region of the label. The adhesive shield includes a moving window, through which the adhesive is sprayed, surrounded by a heated overspray-intercepting surface. The intercepted adhesive is collected by the surface and drains into an adhesive collector for recycling.




The label adhesive station can be used with different types of labeling machines. For example, one type passes a continuous length of label material along the outer surface of a label supporting and cutting assembly. The outer surface preferably has a number of slots through which blades pass to cut the length of label material into cut labels. Another type of labeling machine cuts the label from continuous label material using a rotary anvil, around which the label material passes, and a rotary die registered with the rotary anvil. The rotary die has a blade which cuts the label material resting on the rotary anvil. The waste material surrounding the die-cut label is then removed and preferably recycled.




A primary advantage of the invention is that it is especially useful for running rolls of uncut label material made of polystyrene and/or polyethylene and/or other plastic material. The invention is especially useful for applying shaped labels, typically made of polystyrene, polypropylene or other plastic materials, to rectangular HDPE containers used in the dairy and allied industries. With the invention the cost of labels can be reduced and the ease of recycling is greatly enhanced. Other recyclable label material can also be used. The costs of using the present invention are expected to be reduced by about 30 to 50 percent over the cost of self-stick labels conventionally used with HDPE containers.











Other features and advantages of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings.




BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a somewhat simplified plan view of a first embodiment of a labeling machine made according to the invention;





FIG. 2

is a front elevational view of the labeling machine of

FIG. 1

;





FIG. 3

illustrates a portion of the rotary cutting drum of

FIG. 1

showing a blade assembly and label shifting groove together with air holes positioned along the label supporting surface and within the label shifting groove;





FIG. 4

is a side view of the apparatus of

FIG. 3

illustrating the path of the tip of the blade;





FIG. 5

is a schematic top plan view identifying the rotary regions at which the air holes in the rotating label supporting surface of

FIGS. 3 and 4

are supplied with vacuum, to secure label material to the surface, and with pressurized air, to help dislodge the cut label from the surface as the label is adhered to the container;





FIG. 6

is similar to

FIG. 3

but with label material adhered to the label supporting surface and with the blade at the upper end of its stroke creating a cut label;





FIG. 7

is a simplified overall view of an adhesive shield and an adhesive collector of

FIG. 1

;





FIG. 7A

is a partially schematic illustration showing a crank arm assembly used to oscillate the adhesive shield of

FIG. 7

;





FIG. 8

is a simplified plan view of a second embodiment of a labeling machine made according to the invention;





FIG. 9

is an enlarged view of the rotary anvil roller and rotary die cutter roller of

FIG. 8

;





FIG. 10

illustrates a cut label and label scrap created by the rollers of

FIG. 9

;





FIGS. 11 and 12

are simplified plan and side views of a third embodiment of an adhesive station made according to the invention.











DESCRIPTION OF THE SPECIFIC EMBODIMENTS





FIGS. 1 and 2

illustrate a labeling machine


2


made according to certain aspects of the present invention. Labeling machine


2


includes a stand


4


to which the various components are mounted. Labeling machine


2


is used adjacent to a conveyor


6


along which various containers


8


to be labeled are driven. Label material


10


is supplied as a continuous length of material from a label material roll


12


supported by stand


4


. Label material


10


passes along a label path


14


from roll


12


to a label application station


16


as is discussed in more detail below.




The initial portion of label path


14


is defined by a label material feed assembly


18


. Label material feed assembly is generally conventional and includes a driven label feed roller


20


which drives label material


10


between the roller and pinch roller


22


. Label material feed assembly


18


also includes a label tensioning roller


24


and several idler rollers


26


to ensure the proper tension is maintained on label material


10


.




Label material


10


advances to a label supporting and cutting assembly


28


. Assembly


28


includes a rotating drum


30


. In the preferred embodiment there are eight equally spaced blade assemblies


32


positioned at the periphery of drum


30


, that is adjacent to the label supporting surface


34


of drum


30


. See also

FIGS. 3-5

. Situated between each blade assembly


32


is a label shifting groove


64


formed in label supporting surface


34


. Label material


10


is adhered to label supporting surface


34


through the use of various air holes


38


formed in surface


34


. Air holes


38


are coupled, through correspondingly located air ports


39


, to a vacuum source, a pressurized air source or neither depending upon the rotary orientation of drum


30


. Each air port


39


typically supplies air or vacuum to one, two, or three columns of air holes


38


. As shown in

FIG. 5

, a vacuum is applied to air holes


38


over rotary regions


40


and


42


while air holes


38


are connected to a pressurized air source over rotary region


44


and neither a vacuum nor a pressurized air source over the remainder rotary region. The application of this vacuum over rotary regions


40


,


42


adheres label material


10


to surface


34


. The vacuum applied over region


40


is less than that applied over region


42


to accommodate proper registration of label material


10


on surface


34


, discussed below.




Each blade assembly


32


includes a reciprocating blade


48


which passes through a blade slot


50


formed in label supporting surface


34


. Each blade is driven along blade slot


50


when that blade assembly


32


reaches a cutting position


52


shown in FIG.


5


. Blade


48


is driven upwardly so that the tip of blade


48


passes along an angled path


56


by a pneumatic blade reciprocator


58


. The result of this movement is shown in

FIG. 6

which illustrates a cut label


60


to the left and the next label to be cut to the right with their opposed, newly cut edges


62


abutting one another.




Because nothing is ever perfect, cut label


60


from label material


10


will, sooner or later, stop being registered, that is properly centered, between each blade slot


50


. Registration of label material


10


is achieved in a simple manner. Each blade slot


50


is positioned so that the distance between adjacent blade slots is slightly smaller, such as 0.005 inch (0.13 mm) smaller than the nominal width of each label. This means that the off-center positioning of the labels will only be in one direction. When it is determined, typically using conventional optical sensing of registration marks along the edge of a label, that the labels have been shifted by a predetermined amount, such as 0.1 inch (0.25 mm), then a vacuum is applied to air holes


68


in a label shifting groove


64


through an air port


65


when groove


64


is at a position


66


; position


66


is adjacent where label material


10


first contacts surface


34


. Doing so pulls a little extra label material


10


into groove


64


. This application of a vacuum to air holes


68


formed in label shifting groove


64


at position


66


typically occurs for two or three successive label shifting grooves to shift the label a predetermined amount, such as 0.2 inch (0.5 mm). Positioning shifting position


66


close to where label material


10


first contacts surface


34


of drum


30


helps to prevent the stretching of the label material which could otherwise occur.




Cut labels


60


then proceed to an adhesive station


70


. An adhesive application assembly


72


includes a hot melt unit


74


, see

FIGS. 1 and 2

, coupled to a heated adhesive sprayer


76


by a line


78


. Assembly


72


also includes a heated adhesive shield


80


, see

FIGS. 1

,


5


,


7


and


7


A, which is mounted for oscillatory movement about the center


81


of drum


30


by support arm


82


. Shield


80


includes a window


84


.




During operation drum


30


rotates in a clockwise direction in

FIGS. 1 and 5

so that as a cut label


60


approaches adhesive station


70


, shield


80


pivots in a counterclockwise direction a short distance, such as 2 inches (5 cm), using a crank arm assembly


83


(shown only in FIG.


7


A). The timing of the oscillation of shield


80


is chosen so that once blade slot


50


, and thus opposed cut edges


62


of labels


60


are centered on window


84


, adhesive shield


80


is pivoted in a clockwise direction at generally the same rate of speed as drum


30


.




It has been found that certain adhesives tend to string between adjacent labels. Therefore, in some situations it may be necessary to use a thin divider, such as a vertical divider (not shown) bisecting window


84


. Using a divider helps shield opposed cut edges


62


from heated adhesive


88


sprayed from sprayer


76


as shown in FIG.


5


. For example, for a label


60


having a width of 9.375 inches (23.8 cm) and a height of 4 inches (10 cm), window


84


has a width of 1 inch (2.5 cm) and a height of 3.875 inches (9.8 cm); a vertically-extending divider 0.25 inch (0.63 cm) wide is centered within window


84


. Window


84


is sized to provide a strip of adhesive adjacent to cut edges


62


. However, divider


86


helps prevent a buildup of adhesive at cut edges


62


. The need for divider may be eliminated depending on the characteristics of the particular adhesive used. Also, the need to oscillate adhesive shield


80


may be unnecessary depending on the circumstances. However, at higher rates of speed, an oscillating heat shield is often desired for proper adhesive application.




Adhesive shield


80


includes a heated surface


90


surrounding window


84


which intercepts adhesive overspray. Surface


90


is heated to the temperature of adhesive


88


to keep it flowable. Adhesive


88


which does not pass through window


84


but contacts surface


90


is directed down surface


90


into a heated adhesive collector


92


. Adhesive collector


92


is coupled to hot melt unit


74


by a line


94


so that collected overspray adhesive can be recycled so that the overspray is not wasted.




Cut labels


60


, with adhesive


88


applied thereto, are then applied to containers


8


at label application station


16


. Label application station


16


is generally conventional and includes an infeed star


96


which removes containers


8


one at a time from conveyor


6


and transfers these containers to a transfer star wheel


98


which passes the containers to a roll-down pad


100


. The containers are captured between roll-down pad


100


and cut label


60


so that the container rolls along the surface of roll-down pad


100


and cut label


60


. Label


60


, with an adhesive applied thereto, is applied to container


8


in a conventional manner. Labeled containers


102


then exit from label application station


16


and continue along conveyor


6


.




In use, label material


10


moves along label path


14


, that is through feed assembly


18


and onto vacuum surface


34


of drum


30


. The vacuum applied to air holes


38


along rotary regions


40


,


42


pulls label material


10


against surface


34


. Any label material registration is accomplished by providing vacuum to air holes


68


at label shifting grooves


64


. Label material


10


is cut into cut labels


60


at cutting position


52


by blades


48


. Adhesive


88


is sprayed onto the trailing edge of one label and the leading edge of the adjacent label


60


using adhesive application assembly


72


. Cut label


60


, now with adhesive


88


applied along the leading and trailing cut edges


62


, are then applied to containers


8


at label application station


16


. Labeled containers


102


are then discharged into conveyor


6


. The various operations of machine


2


are controlled in a conventional manner by a commercial controller, such as that made by EMP of New York, using a control panel


104


.





FIG. 8

illustrates a labeling machine


106


which uses an adhesive application assembly


72




a,


similar to assembly


72


of

FIGS. 1-7

, with like elements referred to by like reference numerals. In the preferred embodiment label material


10




a


is a material compatible with and suitable for recycling with HDPE containers


8




a,


such as polystyrene. Label material


10




a


passes idler rollers


26




a,


between label feed roller


20




a


and pinch roller


22




a,


and into contact with a rotary anvil roller


106


, shown best in FIG.


9


. Rotary anvil roller


106


has a generally smooth outer surface


108


but with numerous air holes


110


formed therein. Air holes


110


are connected to a vacuum source, a pressurized air source or neither through air ports


111


in roller


106


according to the rotary orientation of roller


106


. After contacting surface


108


of roller


106


, label material


10




a


passes into a nip


112


created between roller


106


and a rotary die cutter roller


114


. Rotary die cutter roller


114


has a number of relatively short, radially outwardly extending circumferential knife blades


116


each outlining the circumference of a label to be cut from label material


10




a.


In the preferred embodiment knife blades


116


are about 0.0625 inch (1.6 mm) high. The proper spacing between rollers


106


,


114


is maintained by positioning rollers


106


,


118


so that their respective annular end surfaces


118


,


120


touch.




Passing label material


10




a


between rollers


106


,


114


creates cut labels


60




a


and label scrap


122


as suggested in FIG.


10


. Cut label


60




a


remains adhered to surface


108


of roller


106


by virtue of the vacuum applied to holes


110


. Only when cut label


60




a


has reached a position opposite where the label is to be transferred to a label transfer surface


136


described below is the vacuum applied to holes


110


released; at that point a pressurized air supply is coupled to holes


110


through corresponding ports


111


to help direct cut label


60




a


towards the label transfer surface.




To effectively remove label scrap


122


, roller


114


has air holes


124


formed in its surface in the region surrounding knife blades


116


. Vacuum, pressurized air or neither is provided to air holes


124


through corresponding ports


125


in roller


114


. The provision of vacuum to air holes


124


causes label scrap


122


to be pulled away from cut label


60




a


and roller


106


and be temporarily adhered to roller


114


. The vacuum applied to holes


124


is released and the holes are then connected to a pressurized air source to help release label scrap


122


into the inlet


126


of a vacuum line


128


connected to a vacuum scrap recovery container


130


.




Cut labels


60


are released from anvil roller


106


to a label transfer turret


132


. Label transfer turret


132


has, in this embodiment, eight radially-extending arms


134


. Each arm


134


has a label transfer surface


136


having perforations which are fluidly coupled to a vacuum source, a source of pressurized air or neither according to the rotary position of surface


136


. Each surface


136


has a radius of curvature with the center at the center of turret


132


. Cut labels


60




a


are transferred from roller


106


to arcuate surface


136


as surface


136


passes adjacent surface


108


of roller


106


. During this time pressurized air is applied to holes


110


which are covered by the particular cut label


60




a


to be transferred while the holes in surface


136


are connected to a vacuum to cause cut labels


68


to adhere to transfer surface


136


.




When a label


60




a


mounted to label transfer surface


136


reaches adhesive station


70




a,


heated adhesive


88




a


is sprayed through a window in heated adhesive shield


80




a.


If the entire surface is to have adhesive


88




a


applied to it, the window in heated adhesive shield


80




a


is generally the same size as cut label


60




a.


Alternatively, the window in shield


80




a


could be smaller to apply adhesive to particular regions of cut labels


60




a,


such as the leading and trailing edges. For simply-shaped labels, such as that shown in

FIG. 10



a


as cut label


60




a,


shield


80




a


can generally be stationary. However, for other shapes or for different types of adhesive application patterns it may be desired or necessary to have shield


80




a


oscillate to achieve the desired adhesive pattern.




Label


60




a,


with adhesive


88




a


applied thereto, is then applied to container


8




a


as the container passes label application station


16




a.


As surface


136


passes label application station


16




a


the holes in the surface may be temporarily connected to a source of pressurized air so to dislodge any label which may have, for whatever reason, not been transferred from surface


136


.




In use, label material


10




a


is unrolled from label material roll


12




a


by label feed roller


20




a


and directed onto surface


108


of anvil roller


106


. Label material


10




a


on surface


108


is then engaged by knife blades


116


carried by rotary die cutter roller


114


to cut out individual labels


60




a.


Label scrap


122


is collected into a vacuum scrap recoveryb container


130


and labels


60




a


are transferred to surfaces


136


of the passing arms


134


of turret


132


. Adhesive


88




a


is then applied to cut labels


60




a


by adhesive application assembly


72




a.


A label


60




a,


with adhesive


88




a


applied thereto, is then adhered to the surface of a container


8




a


at station


16




a.


Containers


8




a


are properly driven along label application station


16




a


by a feed screw


138


. The now-labeled container then continues down conveyor


6




a.







FIGS. 11 and 12

illustrate an adhesive application assembly


72




b


and a label transfer turret


132




b


similar to the embodiments of

FIGS. 1 and 8

with like elements referred to by like reference numerals. Label transfer turret


132




b


has a number, in this embodiment eight, radially outwardly extending arms


134




b.


Each arm


134




b


has a label transfer surface


136




b


having numerous perforations coupled to a vacuum source, a source of pressurized air or neither according to the rotational position of surfaces


136




b.


Cut labels


60




b


are transferred to surfaces


136




b


in an appropriate manner, such as that illustrated in FIG.


8


. Adhesive application assembly


72




b


includes a rotating, heated shield


80




b


having four windows


84




b


formed therein. As arms


134




b


reach adhesive application station


70




b,


adhesive


88




b


is applied to label


60




b


by sprayer


76




b


spraying adhesive through a window


84




b.


Windows


84




b


are sized and shaped according to the size and shape of label


60




b


and the desired adhesive spray pattern.




Rotating heated shield


80




b


thus acts a continuously moving, heated adhesive shield. The rotation of shield


80




b


is timed to accurately match the movement and position of each label


60




b


carried at the end of each arm


134




b


as label


60




b


reaches adhesive application station


70




b.


By the accurate registration of windows


84




b


with label


60




b


as well as the appropriate sizing of the window, permits adhesive


88




b


to be applied very accurately, including to the edge of the labels, without any appreciable overspray escaping from adhesive shield


80




b


resulting in a higher quality label. The label with adhesive applied thereto is applied to the container at label application station


16




b.


A vacuum is applied to surfaces


136




b


from a label pick-up station


140


until just before label application station


16




b.


Upon reaching label application station


16




b,


positive air pressure as applied to the holes in surface


136




b


to help transfer label


60




b


from its arm


134




b


to the container. The transfer to the container can be done in a number of ways, including that shown in FIG.


8


. From station


16




b


to just before station


140


, neither pressurized air nor partial vacuum is applied to surface


136




b.







FIG. 12

illustrates the shape of one surface


136




b


having 5 sides. The shape of surface


136




b


can, but need not, correspond to the shape of the label


60




b.



FIG. 12

also shows how sprayer


76




b


is supported at a stationary position within rotating adhesive shield


80




b


by an L shaped support


142


. Oversprayed adhesive is collected by the heated inner surface


144


of rotating, heated adhesive shield


80




b


where it flows downwardly onto conical surface


146


and through central discharge opening


148


for collection and reuse. As suggested in

FIG. 12

, the shape of windows


84




b


may correspond generally to the shape of label transfer surface


136




b


and of label


60




b.






Other modifications and variations can be made to the disclosed embodiments without departing from the subject invention as defined in the following claims. For example, collector


92


could be incorporated into shield


80


. Labels may be transferred to the adhesive application station by other than a turret, such as by a moving belt or a rotary drum. The labels can be of any number of different regular or irregular shapes. The moving heated shield could be replaced by other types of moving heated shields, such as a moving belt or rotary disk having one or more windows.



Claims
  • 1. A method for applying adhesive to a label comprising the following steps:moving a label past an adhesive station along a label path; moving an adhesive shield, comprising a moving window surrounded by a heated overspray-intercepting surface, between a heated adhesive sprayer and the label path; spraying heated adhesive through the moving window and onto the label by the adhesive sprayer; intercepting adhesive overspray by the heated overspray-intercepting surface; and collecting said adhesive overspray from the adhesive shield.
  • 2. The method according to claim 1 wherein said label moving step comprises the step of continuously moving the label past the adhesive station.
  • 3. The method according to claim 1 further comprising the steps of:removing a length of label material from a source of label material; and forming a series of labels from the length of label material.
  • 4. The method according to claim 1 wherein said adhesive shield encircles said heated adhesive sprayer and said step of spraying comprises spraying said heated adhesive outwardly through said moving window.
  • 5. The method according to claim 3 wherein the removing step is carried out using a roll of label material as the source of label material.
  • 6. The method according to claim 3 wherein the forming step is carried out using a rotary die cutter element and an opposed rotary anvil.
  • 7. The method according to claim 6 further comprising the step of removing scrap label material following the forming step.
  • 8. The method according to claim 6 wherein the scrap material removing step comprises the step of temporarily applying a vacuum to portions of said rotary die cutter element so to pull said scrap label material away from said labels.
  • 9. The method according to claim 3 wherein the forming step is carried out by directing said label material against a label material-supporting surface and moving a blade along said label material-supporting surface so to cut said label material into labels.
CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 09/024,886, filed Feb. 17, 1998, now U.S. Pat. No. 6,045,616, titled “Adhesive Station and Labeling Machine”, which claims the benefit of the following Provisional Patent Applications: application Ser. No. 60/039,555, filed Feb. 25, 1997, titled “Labeling Machine”; application Ser. No. 60/040,544, filed Mar. 12, 1997, titled “Labeling Machine with Label Transport Turret”; and application Ser. No. 60/046,699, filed May 14, 1997, titled “Labeling Machine and Method”. The disclosure of each is incorporated by reference.

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Provisional Applications (3)
Number Date Country
60/039555 Feb 1997 US
60/040544 Mar 1997 US
60/046699 May 1997 US
Continuation in Parts (1)
Number Date Country
Parent 09/024886 Feb 1998 US
Child 09/301955 US